Shoreham

SPCC Logo
SPCC Brand.

Location:

Clinker manufacture operational: 1883-04/1991

Approximate clinker production: 16.6 million tonnes (27th)

Raw materials:

Ownership:

The Beeding Portland Cement Co. was founded by Richard Ballard in 1878, but there is no indication that cement was made (at least at this site) until 1883. Six Johnson chamber kilns were in operation by 1890: output 144 t/week. The plant was taken over by the Sussex company in 1897, and was considerably extended, with 8 Michele chamber kilns, 2 Schneider kilns to burn the excess dried slurry of the Michele kilns, and finally two rotary kilns were ordered in 1899. The latter was the first example of an “off-the-peg” kiln package supplied by FLS, and was one of several that pre-empted APCM's abortive attempt to monopolize rotary kiln technology. The kilns started up in 1901, and appear to have run successfully from the outset. This state of the plant is particularly well documented because of a newspaper article published in October 1902. An account of the cosmopolitan early workforce is also given below.

The date of the rotary kiln start-up is of interest because in the article, the company (SPCC) claimed it was the first (apart from a few much earlier failed experiments) in Britain. FLS say the rotary kiln was unknown in Europe before they introduced it, and imply that the Shoreham kilns were the first to operate in Britain. However, the same claim is made for other plants (see article). The actual date of light-up is not known. The FLS date (1899) is clearly of the receipt of the order. Cook gives 1902; presumably the date of the newspaper article, although the latter implies that the kilns had been operating for some time. Francis puts it “after” the Swanscombe kilns of 1901-2. Jackson says 1902. However, Spackman gives a chemical analysis of the rotary kiln clinker dated 1901. It is fair to assume that the light-up occurred very early in 1901. The kilns were numbers 3 and 4 in Smidth’s order list. Numbers 1 and 2 (of almost identical design) were installed at Rørdal (Aalborg), Denmark, and lit up in 1899.

Power for these kilns was by site-generated DC electricity: another first.

The chamber kilns were as follows:

The Schneider kilns were at 519833,108637 and 519835,108644. They started up in February 1900. Their combined output was limited by the amount of surplus dried slurry, and was around 230 t/week when all the Michele kilns were running. Heat consumption was around 4.1 MJ/kg.

After the installation of A3 in 1911, operation of the chamber and Schneider kilns was only during periods of high demand. Plant output was 184 t/d from the rotary kilns, plus 600 t/week from the static kilns. The plant was described in detail in the BPCM 1924 schedule. Chamber kilns 1-10 were removed in 1924, and kilns 11-14 and the Schneider kilns were removed in 1927. Rotary kilns A1 and A2 were removed in 1930 prior to replacement of A3.

It’s not clear why A3 was replaced with the similarly-sized second-hand B1, made up from bits from the kilns at Peters and West Kent. The tyre positions were adjusted to fit on the old kiln’s piers. The rest of the plant site was cleared and a new, minimal plant arrangement was installed. The plant ran intermittently during WWII, finally re-starting in early 1946.

The plant was completely rebuilt, mainly in the chalk quarry, in 1948-1950, and kilns C1 and C2 were two of a set of six ordered from Vickers Armstrongs. Because of the very slow construction, the four kilns supplied to Tolteca and Lichtenburg were up and running in 1949. Many more kilns of the same design were subsequently installed by Blue Circle around the world. The plant re-build was regarded as state-of-the-art at the time by Blue Circle, and a detailed description was given in an article published in various journals. Kiln B1 (renamed C3) was kept in use as top-up capacity, and was modified in 1955/6 by addition of a Berz preheater (a design originally used on lime kilns) fed with filter-cake, “nodulized” by extrusion. This had moisture content 18-20%, compared with the typical slurry moisture of 42.5%. The 1959 Engineer article describes the pressing arrangements after a few years' operation - see below. The system was technically successful (unlike the UK Davis preheater installations – see Wilmington, Bevans, Dunstable) but was separately manned, and the presses were labour intensive, so the operating cost was higher than that of the wet kilns, and it was shut down in the recession of 1967. The plant was used as a pilot for firing with domestic refuse during 1975-1977, before full implementation at Westbury Kilns C1 and C2 were converted for filter cake feed (with no preheater) in 1983. One 20 m3 filter press for each kiln was installed in the quarry. The system proved to be limited by high dust loss loads, and failed to make economic production rates. The plant shut in 1991. Although clay was moved by barge in the early days, rail was used for all other purposes. The plant was on the LB&SC Horsham branch. This closed for all other traffic in 1965, with the section from Shoreham to the plant kept open. However, cement was all-road by 1970, coal supply was made tributary to Northfleet in 1974, and gypsum was last delivered by rail in 1980. The tracks were removed in 1988. Much of the plant including the kilns remain, in a state of increasing dilapidation.

Power Supply

The plant was originally directly driven by steam engines. In 1899, gas engines were installed to operate the rotary kiln coal plant and the new washmills, supplied by a central gas plant. Generators driven by the main steam engines produced electricity to run the rotary kilns. For the 1911 kiln, turbo-generators were added, but seem to have been later replaced with a generating plant driven by two 550 B.H.P. Robey Uniflow steam engines. With the 1933 rationalisation of the plant, it became all-electric, and purchased power from the grid.

Rawmills

Six rotary kilns were installed in three phases:

Kiln A1

Supplier: FLS
Operated: 2/1901-1912, ?1919-?1922
Process: Wet
Location: Hot end 519827,108575: Cold end 519845,108574: completely enclosed.
Dimensions: Metric 18.00×1.500
Rotation (viewed from firing end): anti-clockwise.
Slope: 1/16 (3.583°)
Speed: ?
Drive: 2.24 kW
Kiln profile: 0×1500: 18000×1500: tyres at 2100, 8400, 15900: turning gear at 9375
Cooler: Cooler “vault”, elevator and vertical 3 m i.d. × 4.5 m high drum cooler shared with A2: shared rotary cooler (5.8×1.35) subsequently (1907?) added after drum cooler
Fuel: Coal
Coal mill: indirect: FLS Kominor and tube mill
Exhaust: direct to stack
Typical Output: 25 t/d
Typical Heat Consumption: 9.3 MJ/kg

Kiln A2

Operated: 2/1901-1912, ?1919-?1922
Location: Hot end 519807,108564: Cold end 519856,108560: completely enclosed.
In all other respects identical to A1

Kiln A3

Supplier: Krupp
Operated: 1911-1931
Process: Wet
Location: Hot end 519807,108564: Cold end 519856,108560: completely enclosed.
Dimensions: metric 50.10×2.400
Rotation (viewed from firing end): anti-clockwise
Slope: 1/16.67 (3.440°)
Speed: 0.26-0.52 rpm from DC variable-speed motor
Drive: 30 kW
Kiln profile: 0×2400: 50100×2400: tyres at 2000, 18000, 33000, 47000: turning gear at 31000
Cooler: Rotary Metric 19.75×1.710 beneath kiln
Fuel: Coal
Coal mill: indirect: Krupp combination mill
Exhaust: via drop-out box to stack.
Typical Output: 1911-1914 108 t/d: 1919-1931 134 t/d
Typical Heat Consumption: 1911-1914 9.5 MJ/kg: 1919-1931 8.2 MJ/kg

Kiln B1 (=C3)

Supplier: made up using the rear of Peters A2 (originally FLS) and a new burning zone (by Vickers Armstrong).
Operated: 10/10/1933-12/01/1967
Process: 1933-1955 Wet: 1955-1967 Semi-wet: filter cake from three 4.96 m3 0.8 MPa filter presses fed via an extruder to a Berz preheater. See description.
Location: Hot end 519807,108564: Cold end 519856,108560: completely enclosed.
Dimensions:

Rotation (viewed from firing end): clockwise.
Slope: 1/16.67 (3.440°)
Speed: 0.5-1.4 rpm
Drive: 45 kW
Kiln profile: 0×2070: 1524×2070: 3721×2759: 15265×2759: 16866×2400: 49755×2400: tyres at 2038, 17913, 32868, 46825: turning gear at 30968
Cooler: Rotary 69’8⅞”×7’0” (metric 21.26×2.134) beneath kiln
Cooler profile : 0×2134, 21257×2134: tyres at 4578, 15618. In addition to the 3' grid outlet, the cooler also had a 1'6" perforated (1.5") section between 20190 and 20647.
Fuel: Coal
Coal mill: ?probably direct: Atritor
Exhaust: via ID fan to stack.
Typical Output: 1933-1943 178 t/d: 1944-1954 207 t/d: 1955-1967 235 t/d
Typical Heat Consumption: 1933-1943 7.53 MJ/kg: 1944-1954 7.96 MJ/kg: 1955-1967 4.86 MJ/kg.

Kiln C1

Supplier: Vickers Armstrong
Operated: 1/1951-2/1991
Process:

Location: Hot end 519974,108624: Cold end 520080,108629: completely enclosed.
Dimensions: 350’0”× 11’6”B/10’0¼“CD (metric 106.68×3.505/3.054)
Rotation (viewed from firing end): anti-clockwise.
Slope: 1/24 (2.388°)
Speed: 0.52-1.33 rpm: from 1983, 2 rpm max
Drive: 127 kW
Kiln profile: 0×3048: 3810×3048: 6248×3505: 25870×3505: 28308×3054: 105156×3054: 105765×2121: 106680×2121: tyres at 2743, 21031, 40538, 60045, 79553, 99060: turning gear at 44196
Cooler: Newells Rotary 89’6”×9’0¾” (metric 27.28×2.762) beneath kiln. The coolers were originally 87'6" (+2'6" grid) but were extended by 2' in 8/1954 to cope with excessive oversize.
Cooler profile: 0×2254: 1981×2762: 27280×2762: tyres at 4572, 20422: turning gear at 18136.
Fuel: Coal
Coal mill: direct: two 112 kW No18 Atritors: from late 1980s, second-hand PHI roller mill
Exhaust: via electrostatic precipitator to ID fan then to stack.
Typical Output: 1951-1969 557 t/d: 1970-1983 490 t/d: 1983-1991 434 t/d
Typical Heat Consumption: 1951-1969 7.30 MJ/kg: 1970-1983 7.13 MJ/kg: 1983-1991 5.39 MJ/kg

Kiln C2

Operated: 2/1951 to 4/1991
Location: Hot end 519973,108635: Cold end 520080,108640: completely enclosed.
Typical Output: 1951-1969 555 t/d: 1970-1983 480 t/d: 1983-1991 448 t/d
Typical Heat Consumption: 1951-1969 7.39 MJ/kg: 1970-1983 7.12 MJ/kg: 1983-1991 5.42 MJ/kg
In all other respects identical to C1


Sources:

1902 Newspaper Article

This was an article published in the Sussex Daily News on Wednesday 15th October 1902, as part of a weekly series which also included: Reason's Electrical, Brighton; Tamplin's Brewery, Brighton; the Burgess Hill Brick and Terracotta Works; Rope-making at Hailsham; Dolphin Soap Works, Kingston and Regent Ironworks, Brighton - all, incidentally, extinct in 1991. The article was re-printed as a publicity pamphlet by SPCC around 1911. A number of footnotes mentioned changes since 1902, and these are given in italics.

SUSSEX INDUSTRIES

No.2 - CEMENT MAKING: Sussex Portland Cement Company

The manufacture of Portland cement is a process with the details of which the public generally are probably quite unfamiliar. As a rule the idea of the uninitiated is that it has some relation to chalk, and perhaps one or two other substances. That the process of manufacture is on quite an elaborate scale, requiring complicated and perfectly adjusted machinery, many processes needing the most careful supervision, a great number of delicate chemical tests, and the employment of a considerable amount of skilled labour, is occasion for surprise to the majority of people. Yet this industry is one which should be of particular interest to Sussex, for it is this county which possesses two cement works of importance, where the process of manufacture is carried on by the aid of the very latest improvements. The history of Portland cement is in itself of much interest, but it is sufficient here to say that it is made, to use general terms, by the grinding together and calcining of chalk and clay. The name "Portland" was applied to it in consequence of the resemblance which the cement bore to the limestone found near Portland in England.

FORMATION OF THE SUSSEX COMPANY

The Sussex Portland Cement Company was formed, and the construction of the Newhaven Works started in 1884 by Mr A. E. Carey, the then resident engineer of the Newhaven Harbour Works, and Mr A. J. Jack, another engineer, connected with the same works. The Newhaven works were erected at Heighton on a portion of the estate of the late Viscount Hampden, who took great personal interest in the undertaking and materially assisted by his influence and support in the early development of the Company's business. Valuable help was also rendered at the starting of the concern by the late Mr. George A. Wallis (then agent to the Duke of Devonshire), who was a director of the company up to the time of his death. These works, as originally constructed, were designed for an output of 300 tons per week. They were, however, increased from time to time, and are now turning out some 600 tons per week. At the close of 1897 the works of the old Shoreham Cement Company, situate at Beeding, were acquired, the output of these works at that time being about 100 tons per week. These works have been practically reconstructed since the Sussex Portland Cement Company took them over, and they are now capable of an output of 800 tons per week, making the total output of both works 72,800 tons per annum. The number of men employed on the two works is over 300, a large proportion of these men being housed in the Company's own cottages, erected adjacent to the works. The members of the present Board of Directors, viz:- The Hon. A. G. Brand, M.P., Mr. Edward Eagar, Mr. F. G. Courthope, Mr. A. J. Jack, and Mr. J. F. Plaister, have been associated with the management of the Company since it commenced active operations in 1886, and they are all resident in Sussex. Mr. Jack was appointed General Manager in 1887, which post he continued to hold until 1891, when he resigned and joined the Board, continuing to act as Consulting Engineer to the Company. Mr. Plaister, the present Managing Director (who had assisted in the management since the commencement of 1887), then assumed the control. A representative of the "Sussex Daily News" recently visited the Company's works both at Newhaven and Shoreham, and was shewn the processes adopted from first to last, beginning with the procuring of the raw material and ending with the despatch of the finished article.

THE NEWHAVEN WORKS

Newhaven 1902

When the works at Newhaven were started in September, 1884, the downs sloped gently to the roadway. Since that time, no fewer than eight acres of chalk soil have been cleared, and where the hill side formerly declined gradually to the valley of the Ouse, it is now perfectly level ground. On the top of the hill, a tumulus once existed, and an old Roman brooch (now in the museum at Lewes) was found near this spot. The chalk, of course, is here in abundance and the other portion of the raw material, gault clay, is obtained by the Company from a pit at Glynde, the railway affording every facility for transit. There is an extensive face of chalk at Newhaven, the hill in one place having been cut right through. No less than 98 per cent of carbonate of lime is contained in the chalk here, and this a great advantage in view of the purpose for which the chalk is required. In order that night may not interfere with the cutting away of the hill side, a travelling electric light, capable of journeying along the whole face of the cliff, is used, its rays being directed upon any spot where work is going on. The proportion of chalk to clay is, speaking roughly, three to one. The chalk is brought whence it is cut to the washmill in trucks which run along a small railway. These trucks work on a hinge, so that the load is easily tipped, and the contents emptied into the mill's mouth. A similar course is followed with the clay. Inside the mill a process, quite terrifying in appearance, goes on. The mixture is churned and ground and stirred by harrows, while a small stream of water constantly flows in. The effect of the washing is to get an intimate compound, and to reject the useless matter, such as flints, which are not required. When the washing process has been duly accomplished the stuff is passed through a fine grating which stops the flints, &c., and allows the passage only of the washed chalk and clay, which from this point is technically called slurry. The latter then goes into a "mixer", where are left behind those small flints which have not previously been eliminated. From the "mixer" the slurry is "elevated" by a series of buckets on a wheel, and every bit is ground as small as possible between mill stones. In fact one of the most important stages in the manufacture of the cement is to get this stuff ground fine enough, though up to recent years this part of the process was considerably neglected in most of the English Works. The slurry has now to pass through a 180-sieve, which is a sieve containing 32,000 meshes to the square inch; and it is important that the residue should not exceed five per cent. As a matter of fact, the Company grind their residue to three per cent. Constant tests are made in order that this fineness should be secured. By means of powerful pumps the slurry is now conveyed to the drying floors, which are fitted with flues in order that the waste heat from the kilns, which adjoin them, shall pass over and under them, drying the slurry and converting it into what is technically designated "slip". As the slip dries, it is broken up and wheeled into the kilns, where it is deposited with alternate layers of coke.

TWENTY THOUSAND TONS OF COKE

The consumption of fuel by this method is about half a ton of coke to a ton of cement, and the quantity of coke consumed per annum is 20,000 tons. The fumes and moisture from the kilns are carried off from the drying floors by means of high chimneys. When the kilns are lighted, they are sealed up in front and at the bottom, and a fresh quantity of slurry is run on to the drying floors. Thus, while the kilns are burning, they are at the same time drying other floors of slurry. There is a range of 21 kilns, and the time a kiln takes to burn through and dry a floor is four or five days. The burning process, too, is most important, for it is necessary that the contents of the kiln should be burnt thoroughly, but neither over nor under burnt. If they are over burnt they are of no value at all, while under burnt material is of inferior quality, and likely to do harm in the work for which it is used. In consequence of this the kilns require very careful attention. After the stuff is burnt, the change in its composition has a corresponding change in name, and what was slurry now becomes clinker, the effect of the burning being to drive out the carbonic acid gas and to bring about chemical combinations of the lime and clay. All partly burnt stuff has to be carefully removed, and a special staff of men is engaged for this purpose.

Pamphlet footnote: Since the above was written, a Rotary Kiln plant of the latest type has been installed at the Newhaven Works.

Trucks are run right into the mouth of the kilns, where they are filled, then they are taken by a tramway over a weighing bridge, where they are weighed and the weights registered. The clinker is then passed through two large crushers into a "hopper", which feeds the ball mills, consisting of drums half full of heavy steel balls, and the revolutions of which grind the clinker down to a certain degree of fineness. From the ball mills the stuff is passed through a sieve into a hopper, and thence into the tube mills, which finish this process by grinding the clinker into an impalpable powder. The last grinding is, of course, most essential and complete; and when the process is ended the cement will pass through a sieve, having 5776 meshes to the square inch, leaving a residue of no more than five per cent. This is the result of ordinary grinding, but the machinery now is so excellent that the cement can be ground to nearly any degree of fineness; indeed, the Company have a special specification, where it has to pass through a sieve with 32,000 meshes to the square inch, leaving a residue not exceeding ten per cent.

The pamphlet changed this to 15%! In modern cements, this quantity is essentially zero.

Formerly this grinding was done by mill stones.

A STORE FOR 8,000 TONS

After passing through the tube mills the cement is elevated into an automatic weigher; thence into a conveying screw, which takes it the whole length of the store; and it is then dropped into bins, the object of which is to aerate it thoroughly before it is despatched. Bins are kept for various customers. The whole of the cement in each of these bins is tested daily as manufactured until the bin is full; and it is again tested as it is sent out. One advantage of this store (which is lighted by electricity), is that all the work therein is done under cover; and it is so large that there is no necessity to bag the material up until it is actually wanted. This again gives the cement the additional benefit of aeration. On either side of the store are lines of rails, and the trucks run up them under cover. As each truck is filled it is covered with a sheet. After this the trucks leave the works, and their contents are not touched until they reach their destination, every precaution being taken to ensure their arrival at the consumer's in a perfectly dry state. There is space for twenty trucks on each side of the store, and their total contents when full equal 200 tons of cement. With an efficient staff of men this quantity can be loaded in an hour. The storage capacity is 8,000 tons. The bulk of the Company's trade being home trade, the principal part of the packing is done in sacks, and there is a store in which the sacks are kept, but a certain amount is done in casks, and the Company have their own cooperage, where their casks are made.

THE MACHINERY

The engine house contains two compound condensing engines, one of 400 h.p. which drives the dry mill, and a 200 h.p. engine, which drives the wet plant. Adjoining there is an electric installation for the lighting of the whole of the works, and the driving of some of the machinery. The wear and tear of the machinery in all of the departments of cement manufacture is very heavy, and it is therefore most important that it should be maintained in first-class order and every little defect immediately remedied. In order that this shall be effected without delay of the gear being sent away the Company have their own staff of fitters and a large fitting shop, containing all necessary lathes, shaping machines, etc. This machinery is driven by electricity. The fitting shop is built entirely of concrete, and adjoining is the smith's shop. Before the company did away with the mill stones in favour of new dry grinding machinery they decided to put up an additional mill, on the most modern lines. The new mill is driven by a compound condensing engine of 250 h.p. of the marine type. The mills are all on one floor, and instead of feeding into a crusher, trucks are brought direct from the kilns into the elevator and are emptied direct into the ball mill. What follows then is practically the same as before, but afterwards the cement is brought into a belt conveyor, which has the double advantage of conveying the cement with the expenditure of less horse power than that necessitated by the screw conveyor, and of being open to the atmosphere, and thus aerating the cement as it is carried along to be dropped on to the screw which delivers it into the bins. A book is kept in each mill for recording the testing of the grinding, which is done every half-hour, sieves being specially provided for the purpose. This is quite independent of the ordinary testing in the testing rooms, each man being responsible for his own department. An automatic weighing machine is also used to see that the proper quantity is being sent through the mills, and the results are duly booked, so that there is little chance of a slip.

AN ELABORATE TESTING SYSTEM

The careful testing of the finished cement and the materials in the various stages of manufacture is imperative, and for this purpose a laboratory and testing room are provided where tests of every possible description are carried on daily by an efficient staff of chemists and assistants. In the laboratory the raw materials, viz., chalk, clay, coal, coke, etc., are constantly tested, and the chemists are also occupied in research work with the view of bringing about further improvements. Nothing is passed into the kilns until it is absolutely certain that the chemical combination is correct. Besides testing the fineness of the grinding of the chalk and clay as passed through the wet mill, a process is adopted to ascertain the carbonate of lime in the slurry; this is done half-hourly or hourly as may be required by means of a chemical apparatus called a calcimeter. These Sussex Works were about the first English Works to adopt this instrument, although its use has since become almost universal in the cement trade. This, like many other scientific processes, is copied from the Germans, whose methods the Sussex Portland Cement Company have been at pains to consider and where advantageous, adopt. After the cement is ground, daily samples of the manufacture are brought into the testing room for chemical examination, and are tested for fineness, setting time, specific gravity, weight per bushel, and breaking strain, also for soundness. The tests for breaking strain are of considerable interest. The cement is mixed with a certain quantity of water and forced into moulds, where it remains for twenty-four hours until thoroughly set. The briquettes thus formed are taken out of the moulds and are placed under water, and allowed to remain there for periods extending over two, six and 27 days, three months, six months, and twelve months. At the end of each of these periods the briquettes are taken out, and broken in the testing machine. The usual requirements of engineers at the present time are a breaking strain of 400 to 450 lbs per square inch after seven days. Of the briquettes, which our representative saw tested, one gave a breaking strain of 590 lbs after seven days, and another, after three months, failed to break at 1000 lbs.

THE MAKING OF BRIQUETTES

For practical purposes, it is the finely ground cement which is of the greatest value. To prove the value of the fineness of the cement it is made up into sand briquettes, the proportion being three of sand to one of cement, and it is very important that the consumer should see that he buys a cement that will give him a good breaking strain with sand briquettes. The breaking strain of a sand briquette required by the average engineer is 200 lbs per square inch after 28 days. The sand briquettes which have remained that time and which our representative saw broken gave breaking strains of 390 lbs and 470 lbs.

These values correspond to modern EN 196 compressive strength values of 18 and 23 MPa. The engineer would apparently accept 7 MPa. The British Standard for cement had not yet been published. Modern 28-day strengths are around 60 MPa.

More importance is attached to this test than to the neat cement test, but these sand briquettes require very careful making; as the comparative results obtained would be useless unless precisely the same conditions were observed for making each briquette, this necessitates the employment of special apparatus and an expert tester. Different times of setting are, of course, required for different purposes. For instance, drainage and sea works require fairly quickly setting cement, while for general work, the time required is longer; and the company naturally make a special point of suiting the requirements of their customers, their system being so perfect that they can prepare their cement to set in any time from twenty minutes to twenty-four hours. Circular pats of cement are tested for the initial and final set by means of a pointed instrument pressed downward by a 2 lb weight, the power which the point has of penetrating the pat giving the extent to which it has set. As a test for soundness, the pat is put on a piece of glass, placed under water, and watched for any signs of cracking, or of coming away from the glass. This test is carried out in fresh water, but there are other tests by means of sea water and boiling. From first to last the results of all the tests are registered. Every process is kept recorded and has been for years past, the results forming quite a library. If a consumer wishes to know the result of the test of any particular supply it can be furnished at once, the tests being registered with the name of the consumer opposite them. A series of tested briquettes is also kept, which can be referred to if necessary, and the Company also have a sample pat of every day' s manufacture since the works were started.

THE SHOREHAM WORKS

Shoreham 1902

In the reconstruction of the Shoreham Works, which are situated at Beeding, the Company were able to allow for many improvements which it was found impossible to adopt at Newhaven, and here the processes are carried out upon what are recognised as absolutely the most modern lines. An exceptional advantage of the Shoreham works is that they are situated on the banks of the river Adur. The result of this is that the Company are able to despatch their cement and receive coal, coke, and other supplies in their own barges by water. The clay for use in the works is brought by barge from the Company's own freehold clay-pit at Horton, about three miles from the works. The unloading is effected by means of a steam crane. One of the cement stores is built on the wharf so that the cement can be loaded into the barges direct from the store. There is a considerably larger face of chalk here, but it is cut out and conveyed to the works on a tramway in exactly the same way as at Newhaven. There is a gas-making plant for driving the gas engines; and on the side of the cliff from which the chalk is being cleared a new washing plant and wet mill, which will be driven by a 250 h.p. gas engine is in course of erection. The process followed as to the chalk and clay is similar to that at Newhaven, but the washing and mixing plant is more elaborate owing to the more modern methods of burning, which require different methods of washing to achieve the same chemical result. At Shoreham there are two washmills and two mixers instead of one of each, so that if one breaks down the other is ready to go on. The new wet plant which is being put up will also be duplicated. The present plant is not sufficient to deal with the larger burning plant without working night and day, and it is the Company's intention to avoid this if possible.

THE GERMAN SCHNEIDER KILN

The drying process is practically the same as at Newhaven, but it was found that so much heat was being wasted in the kilns, that another drying floor was constructed over the top of the kilns on which stuff can be dried to feed German Schneider continuous kilns. This kiln was invented by a German, from whom it takes its name, and is not only economical in the matter of fuel consumption, but also burns more regularly and efficiently than the old type. The slip is taken off the top of the chamber kilns by tramway and fed into the Schneider with layers of coke in a similar way to that adopted in the chamber kilns; only in this instance the quantity of coke required is much less and the kiln is never stopped for drawing, for as fast as fresh stuff is put in to burn the finished material is being removed. There are altogether fourteen chamber kilns and two Schneider kilns. Each Schneider kiln turns out 100 tons of clinker per week, whereas the ordinary chamber kiln only deals with from 25 to 30 tons per week. The process at Shoreham is completely automatic from first to last, the stuff being handled as little as possible.

AN IDEA FROM AMERICA

Having found out what were the methods employed on the continent the Company turned their attention to America, where they found the rotary kiln system in vogue. By this system, which the Company adopted, it is possible to dry and burn the cement and completely manufacture it in 2½ hours, whereas by the old system it takes from ten days to a fortnight. The rotary kiln is fed with the slurry by long pipes leading from tanks, the feed being controlled by one man. The kiln itself is a long inclined cylinder lined with fire bricks, which is made to revolve slowly. The slurry is fed into one end, and as it travels to the further end it gradually dries and burns, eventually dropping out of the lower end of the tube in the form of clinker; but instead of being in large lumps it is in small lumps the size of beans. This kiln ensures perfect burning of the clinker, and there is little or no half-burnt stuff. The burning is done with finely powdered coal, which is blown into the kiln by means of a fan and ignited immediately it enters the kiln. As the clinker falls from the kiln it is taken up in an elevator and dropped into a cooler, whence it is conveyed automatically to the mill to be ground. Coal fuel, being used instead of coke, enables the manufacturer to be more independent, as the coke market is subject to more heavy fluctuations than the coal market, besides which the supply of coke locally, owing to the introduction of water gas, is not nearly so large as it was formerly.

GAS AND ELECTRIC POWER

The whole of this plant is driven by electricity, and it is so admirably arranged that it requires only two men to look after it, one man for each kiln. The Sussex works were the first in England to adopt this system and make it a practical success. Since the plant was started at the Shoreham works it has been running continuously with scarcely a hitch. To start the plant the Company had an advantage over other English cement makers in securing the services of men from Denmark, who had been working a similar plant in that country, which was then practically the only place where lengthy experience of drying and burning slurry with rotary kilns could be gained.

Pamphlet footnote: Since the above was written, a further rotary kiln plant has been installed, capable of an output of 1000 tons per week.

In the works is a 100 h.p. gas engine which drives the coal grinding drying plant for the rotary kilns, in itself quite an elaborate process. The main engine which drives both the wet and dry mills is of 400 h.p.; and the electric plant is driven by a 60 h.p. Parson's steam turbine, and two compound condensing engines. One of the cement stores is similar to that at Newhaven, and there is an additional store nearing completion. When completed the two stores will have accommodation for 9,000 tons. It is possible, in the two stores, with an efficient staff working simultaneously, to load 260 tons per hour, all the work being done under cover. A similar arrangement to that at Newhaven is effected in regard to the trucks, which are brought under cover alongside the bins. As at Newhaven a fitting shop, laboratory, testing room, and competent staff of chemists are provided. There is also a staff of draughtsmen kept, the Company designing all their own works, mills, etc. Both the Newhaven and Shoreham Works are connected by sidings with the London, Brighton and South Coast Railway, which affords every facility for the rapid dispatch of the cement by rail and also for shipment by the Railway Company's wharves at both ports.

SOME GREAT UNDERTAKINGS

The important works supplied by the Company bear ample testimony to the high quality of their cement. To the Newhaven Harbour Works over 17,000 tons were supplied during the construction of the breakwater, which is a fine example of monolithic construction and considerable additional quantities have since been supplied to the Harbour for minor works and repairs. The Company's cement has always proved eminently reliable and suitable for sea works, and has been used for large concrete groynes at Brighton and Hove, also for the Marine Parades and Sea Walls at Brighton, Hove, Bognor and other South Coast watering places, the most recently completed work of the class being the important Sea Defence Works at Seaford and Newhaven. Supplies have also been made to important Dock and Canal Works such as the Manchester Ship Canal, Tilbury and Southampton Docks, and the Alexandra Dock at Newport, Mon. The British Admiralty, when obtaining supplies of cement, specify particularly to tensile strain, fineness, specific gravity, and chemical analysis, and provide for the inspection of the cement at various stages. The Company have supplied the dockyards at Portsmouth, Devonport, and Pembroke Dock; also the Admiralty Works at Portland and Guernsey, and have given every satisfaction. The large blocks of Naval and Military Barracks constructed at Portsmouth during recent years have taken over 6,000 tons. Railway Works also account for large supplies of cement, and the Company has held the annual contract to the L. B. and S. C. Railway for 13 years. The modern application of concrete to drainage foundations, and flooring, has caused an increasing consumption of cement in every locality. Such buildings as the Hôtel Métropole (sic), Brighton (for which 2,000 tons were supplied), large Retort houses and Gas Holder Tanks at important towns, together with Drainage Works and Sewer Outfalls take a considerable portion of the Company's output. The Company has held the important annual contract of the Brighton Corporation for 14 years, and also those of Eastbourne, Folkestone, Torquay, Lewes, Plymouth, and other towns for varying periods. For the Manchester main drainage they supplied over 5,000 tons, and this year they are sending thousands of tons to the same Corporation for important Sewerage Works. Other important jobs now being supplied are the new East Sussex County Lunatic Asylum at Hellingly, the Glasgow main drainage, and the contract, extending over six years, for barracks at Tidworth, Salisbury Plain. This last is one of the largest and most important building contracts ever given out in this country, and the Company have arranged to supply the whole of the cement required.

THE COMPANY AND THEIR EMPLOYEES

One necessary outcome of the situation of the works at Newhaven and at Shoreham has been the springing up of miniature towns in both neighbourhoods. In both cases the works are practically isolated, and it has been with the object of having the bulk of their working population on the spot that the Company have erected rows of cottages for their occupation. Besides the cottages there are houses at both works for the works managers, the latter overlooking the works and thus commanding the whole situation. Some years ago a Sick and Provident Fund was started by which the men receive 12s. a week during illness and doctor's attendance when required; funeral allowances are paid to the widow or other relatives on the death of a workman, and to a man on the death of his wife. Near the Newhaven Works is a commodious Recreation and Reading Room with stage at one end. This stage can be used when entertainments are organised, and at other times can be partitioned off to form Committee rooms. Non-alcoholic refreshments and tobacco are supplied; there are billiard and bagatelle tables, and illustrated newspapers are provided without any expense to the men. During the winter months, entertainments are arranged by a committee elected entirely among the employees, and these are held in this Recreation Room. Moreover, the Company have at their own expense laid out a recreation ground for cricket and football. At the Shoreham works a mess room is provided for those men who come considerable distances. It will thus be seen that the Company have continued the enterprise and forethought they have displayed in prompting their business schemes to the people who work for them, and who benefit accordingly, and it is very probable that this consideration for their workmen has not been the least of those influences which have helped the works to attain their present position.

Pamphlet footnote: Since the foregoing article was written the company have acquired the old established Works of Messrs. Hooper and Company at Southampton, and the total combined output the works are now capable of is 125,000 tons per annum.

The 1911 Plan of Shoreham

Shoreham 1911 plan View HD image in a new window.

There remains a plan prepared around the time of the installation of the third rotary kiln around 1911. I present a version of this. The plan was prepared by the Sussex Portland Cement Company Ltd. It passed into the hands of BPCM when SPCC was absorbed into that combine. After WWII, it was in the hands of Blue Circle's Southern Area Engineering Office, and remained (along with many other wonderful historic plans) in the Shoreham drawing office. I found it there and took photographic images of it around 1990. The whereabouts of the original drawing is unknown to me - it may be out of sight in the local museum, or it may have been destroyed. The plan as reproduced here is my own drawing based on my observations in 1990. The plan and the subsections of it are all my own copyright, as of 11 July 2018.

The original purpose of the plan was to show the layout of pipework around the plant - showing slurry, gas, water and drainage lines. For clarity, I have retained only the slurry lines.

The Shoreham plant started with static batch kilns, and its evolution into a rotary kiln plant (as with other independent - i.e. non-Blue Circle - plants) was compressed into a fairly short period. Because its evolution consisted of multiple sporadic, spur-of-the-moment developments, and took place in a rather cramped site between the road and the river, the plant layout was decidedly chaotic, and was not entirely rationalised until the 1950 re-build. Five distinct blocks of plant, each with its own alignment, can be discerned.

The Chamber Kiln block

Shoreham chamber kiln block

The numbering of the chamber kilns reflects their construction sequence. The plan indicates that by 1911, kilns 1 and 2 were already abandoned. The plan shows the slurry feed lines to the chambers, originating from the washmills via a pipeline running under the road in a shallow accessible trench. Before 1898, slurry came from a washmill on the river wharf. As was common on early chamber kiln plants, in the original setup, whenever a slurry chamber needed filling, the washmill was started up and unblended slurry was pumped up, using a "safe" chalk/clay ratio.

The Schneider kilns were placed so that dry feed could be carried a short distance from the drying chambers, by overhead gantries and platforms. A hoist on the opposite side of the feed platform brought coke from the rail delivery area.

The Finish Mill block

Shoreham chamber kiln block

This and the chamber kilns constituted the original plant. Again, the numbering of the cement bins reflects the sequence of construction. The earliest part was the rectangular building in the centre containing three cement bins and two sets of ball-and-tube mills. There was also a jaw crusher, which was essential for chamber kiln clinker. The main steam engine provided power via lay-shafts. In the drawings, belt-drives are shown schematically in red. Individual items of plant were started and stopped by means of fast-and-loose pulleys. On the opposite side of the engine room was the boiler house - originally just the bottom-right part.

Until 1898, the original washmill was located where the extension (right-hand) boiler was later placed and was powered from the main lay-shaft. Chalk was brought to it by 3 ft gauge tramway running under the main road. The clay was unloaded from barges by steam crane on the wharf.

The grouping of all the plant requiring power around a central power house was a typical arrangement on pre-electric plants. It is likely that the mill house originally contained flat-stone mills, since tube mills did not become available until the mid-1890s. The progressive expansion of the plant required addition of a second mill room with another two mill sets (one under construction) to the left, and five more cement bins. It will be noticed that the bin space expanded much more rapidly than the plant capacity, as it dawned on them that their fiery product needed long aeration (several months!) before being despatched. To meet added power requirements, an extra larger boiler was added on the site of the old washmill, which was by now severely undersized, and electricity generation was added in 1899 for various items in the rotary kiln plant.

The four ball-and-tube mill sets, turned by the central steam engine, remained the finish mill process for the plant until 1933, when the plant was connected to the local power grid, and a single electrically-powered 300 kW combination mill was installed adjacent to the rotary kiln house, as can be seen in the 1934 photograph above.

The Washmill block

Shoreham washmill block

With the expansion of the plant, the single washmill near the wharf was inadequate, and new washmills were installed in 1901. It was logical to place this in the quarry, since slurry could easily be pumped across the road, and the old quarry floor provided unlimited space for longer trains and mixers. For the same reasons, it was convenient to install the new gas plant there. The new washmill was driven by a gas engine, and the coal mills for the rotary kilns were also driven by gas engine.

The gas plant was a combined producer/water gas plant as was installed on many plants - particularly FLS projects - around this period. It looks as though it was extended, perhaps for the rotary kiln project.

The gas engine as depicted appears to be as supplied by Davey, Paxman & Co., Ltd of Colchester, as pictured in a catalogue:

gas engine

It had twin opposed cylinders - a design capable of high power, but later abandoned because of excessive longitudinal vibration.

The first pair of washmills was that on the left. The second pair was added in 1911 with the installation of No 3 rotary kiln. The slurry wheel was used as a means of lifting the slurry, but also acted as a means of separating grit, which dropped out in the sump. Shoreham chalk contains about 5% flint which had to be separated at the washmills. The mixers were 20' diameter sumps below ground level with rotating paddles and had a capacity around 80 m3 each, equivalent to 73 tonnes of dry raw material, or 46 tonnes of clinker, so for flat-out production, they held enough for 18 hours' run. They fed a single 3-throw pump transferring slurry across the road The triple mixer was part of the 1911 extension and had capacity 426 m3 (389 tonnes DRM, 250 tonnes clinker - two days' run for the new kiln).

The Rotary Kiln block

Shoreham rotary kiln block

The two small rotary kilns were FLS's first UK installation, and may have been the first rotary kilns to operate effectively in the UK, in early 1901. Based on an American Lathbury & Spackman design that avoided the standard Hurry & Seaman design used elsewhere, they had somewhat eccentric cooling arrangements, and FLS changed designs radically later in the decade. Coal was ground by a standard FLS Kominor/tube mill set and stored before injecting into a high-pressure firing pipe.

Shoreham Kilns 1 & 2 Kilns 1 & 2: picture courtesy of Chris Down

The kilns were driven by electric motors near the back end, through a train of belts that allowed the speed to be adjusted. A dual paddle mixer was provided, and slurry was delivered to the kilns by constant-flow positive displacement pumps, the feed-rate being controlled by a hand valve diverting part of the slurry back to the mixer.

The new kiln 3 was supplied by Krupp, and was of what became the standard design. The kiln was raised high on four masonry piers, and a simple rotary cooler was threaded through the first and second piers under the kiln. Clinker discharged into a shaker conveyor which in turn discharged into an elevator, then two belt conveyors took it over a gantry to the finish mill feed hoppers. A large covered coal store was provided, and coal was supplied (by hand?) to a double-surface rotary drier - probably Coles - then through a Krupp tube mill, which discharged into an elevator lifting the fine coal into a large hopper over the firing platform.

A new, relatively high stack was constructed for the kiln, constructed with an octagonal design from precast concrete sections grouted onto vertical reinforcement bars.

Whereas Kilns 1 and 2 had been somewhat experimental and intermittent in operation, supplying at most a quarter of the plant's clinker, Kiln 3 represented a commitment to rotary production, and the static kilns became only back-up capacity.

The Despatch block

Shoreham despatch block

The limited cement storage in the finish mill block was supplemented with a separate store in 1902. This was of the FLS "basilica" design, with central bins fed from a central overhead conveyor. Along each side were wide covered aisles on which cement was extracted from the bins - initially by hand - and shovelled into bags which were then loaded directly into covered rail cars. Later a semi-automatic bag filler with screw extractor was put on each bin, and this remained the filling and loading system of the plant until the 1950 re-build.

At the same time a coal reception area was installed to supply the rotary kilns.

Beeding Tied Houses

Between 1898 and 1903, the Sussex Portland Cement Co Ltd built 45 houses for their workforce just north of the Shoreham plant. The census returns for 1901 and 1911 show the development of these, and give an interesting insight into the nature of the workforce.

The fact that most of the houses were crammed with people - often with two households in a house, and numerous "boarders" and "lodgers" - is not surprising. It is typical of the housing in new industrial areas at the time. What is more striking is the cosmopolitan nature of the community, with workers drawn in from all over Britain.

The occupations listed indicate the nature of the workforce at a plant that at the time was still predominantly based on static kiln production. Many of those labelled simply as labourer probably had more specialised jobs than this implies. By far the most common specialised occupation mentioned is "kiln loader", digging dried slurry from the chambers of chamber kilns, and transferring it to the kiln for burning. In the 1911 census, there were also a number of contractors, working on the Kiln 3 installation, who had been billeted in the company housing.

The 1901 census took place on 31st March, and finds the development partially built, with 17 houses in occupation, and a further ten under construction. Many who subsequently moved in were at this time living in the surrounding villages. Svend Caspersen, one of two Danes supplied by F L Smidth, was staying with his wife in the same house as the chief engineer. These two came for the construction and commissioning of the first two rotary kilns, and stayed, on and off, for nearly ten years.

There were at this stage in total 92 people - 61 male and 31 female, the sex ratio indicating the large number of single male immigrants. There were 5.4 people per house on average minimum 2, maximum 8).

AddressNameAgeOccupationBirthplaceBirth County
Cliff HouseThomas Don32ForemanPlaistowLondon
1 Dacre GardensJames C Woolson29Kiln LoaderWarminghurstSussex
1 Dacre GardensWilliam F Kneller21TimekeeperBroughtonHants
1 Dacre GardensAlbert Double24ForemanSouthwickSussex
2 Dacre GardensHenry Masterson43Cement MillerIslingtonLondon
2 Dacre GardensAlfred Salmon29Fitter's MateBures St MarySuffolk
2 Dacre GardensEdwin Richards24Kiln LoaderShorehamSussex
2 Dacre GardensArthur Plumb22Kiln LoaderSudburySuffolk
2 Dacre GardensWilliam Snelling21FitterSouthwickSussex
2 Dacre GardensCharles Gibbs20Fitter's MateSnodlandKent
3 Dacre GardensJames Roberts38QuarrymanSteyningSussex
3 Dacre GardensWilliam G Cherriman22LabourerWest GrinsteadSussex
3 Dacre GardensCharles Cherriman19LabourerUpper BeedingSussex
4 Dacre GardensWalter Moase37Kiln LoaderParhamSussex
4 Dacre GardensThomas Clarke37Kiln LoaderBostonLincs
4 Dacre GardensEdward Hayles24BricklayerFindonSussex
5 Dacre GardensErnest J Chalcraft28Kiln LoaderSteyningSussex
5 Dacre GardensWilliam Avis38Engine FitterLambethLondon
6 Dacre GardensAlbert Elliott39LabourerStorringtonSussex
6 Dacre GardensLeonard Elliott16LabourerBotolphsSussex
6 Dacre GardensAbraham Hunt19LabourerBoxgroveSussex
6 Dacre GardensJoseph Kenyon32LabourerBurnleyLancs
7 Dacre GardensAlfred E House22LabourerBuckland NewtonDorset
7 Dacre GardensNelson House21Kiln LoaderBuckland NewtonDorset
7 Dacre GardensThomas House15Kiln LoaderBuckland NewtonDorset
7 Dacre GardensFrederick Woolen38WeighmanDevizesWilts
8 Dacre GardensRichard Nulley42StokerBrightonSussex
8 Dacre GardensFrederick Truegrow40LabourerHenfieldSussex
8 Dacre GardensJohn Brown49LabourerHastingsSussex
8 Dacre GardensHenry Gibbins50LabourerHastingsSussex
9 Dacre GardensEdward Terry45StorekeeperWindsorBerks
9 Dacre GardensEdward W Terry13Trolley boyHastingsSussex
9 Dacre GardensWilliam S Parker24LabourerBrightonSussex
10 Dacre GardensJoseph Holder23SlurrymanBrightonSussex
10 Dacre GardensHugh Campbell22Chemical AnalystCrieffPerth
11 Dacre GardensEdmund Packham45Engineering ForemanPimlicoLondon
11 Dacre GardensSvend Caspersen27Cement ExpertDenmark
12 Dacre GardensJohn O Brand28Engine FitterWickham MarketSuffolk
19 Dacre GardensGeorge Dick17LabourerFinsburyLondon
19 Dacre GardensJames Holder20LabourerHenfieldSussex
19 Dacre GardensThomas Woolgar18LabourerHenfieldSussex
20 Dacre GardensJoseph Mallinson30FitterLongwoodWest Yorks
21 Dacre GardensFrederick Hall46CarpenterLondonLondon
22 Dacre GardensAlfred Simmons25BricklayerBrightonSussex

The 1911 census took place on 2nd April, and by now occupancy was reaching a mature stage. There are many names among the residents that were familiar throughout the subsequent history of the plant.

There were at this stage in total 287 people - 163 male and 124 female. There were 6.4 people per house on average (minimum 3, maximum 12).

AddressNameAgeOccupationBirthplaceBirth County
Cliff HouseAlbert Double34ManagerSouthwickSussex
1 Dacre VillasAlfred S Shelbourne34Foreman FitterHitchinHerts
2 Dacre VillasWilliam Ollerenshaw50Electrical EngineerClayton-le-moorsLancs
2 Dacre VillasJames Keith Campbell26Chemical AnalystCrieffPerth
1 Dacre GardensJoseph Holder33MillerBrightonSussex
1 Dacre GardensBenjamin Brear32Civil EngineerAddinghamWest Yorks
1 Dacre GardensJoseph Brear18CarpenterAddinghamWest Yorks
2 Dacre GardensHedley Early41Engine FitterWantageBerks
2 Dacre GardensHarry Early16Electrician's MateWorthingSussex
2 Dacre GardensAlfred Salmon39Stationary Engine DriverBures St MarySuffolk
3 Dacre GardensWilliam George Brown41Kiln DrawerPoplarLondon
4 Dacre GardensWalter Moase47Rotary Kiln BurnerParhamSussex
4 Dacre GardensGeorge Moase17Laboratory AssistantBramberSussex
4 Dacre GardensThomas Clarke48Schneider Kiln BurnerBostonLincs
5 Dacre GardensErnest J Chalcraft39Kiln LoaderSteyningSussex
5 Dacre GardensHenry Thompson32LabourerBournemouthHants
6 Dacre GardensFrederick Carr29LabourerNutleySussex
7 Dacre GardensWilliam M Scott32Fitter's MateGlasgowLanark
7 Dacre GardensCharles Gladman36LabourerAngmeringSussex
7 Dacre GardensGeorge Gladman15LabourerAngmeringSussex
8 Dacre GardensJames Fieldwick37LabourerFletchingSussex
8 Dacre GardensFrank Pierce26LabourerWokingSurrey
8 Dacre GardensWilliam Skinner21LabourerBrightonSussex
9 Dacre GardensEdward Terry55StorekeeperWindsorBerks
10 Dacre GardensWilliam Langley35Stationary Engine AttendantHenfieldSussex
11 Dacre GardensJohn H May42Gas Plant OperatorBrightonSussex
12 Dacre GardensWalter T Dalton52Cement MillerDarenthKent
19 Dacre GardensAlfred Simmons35BricklayerBrightonSussex
20 Dacre GardensThomas Searle61LabourerStorringtonSussex
20 Dacre GardensThomas Searle31LabourerSteyningSussex
20 Dacre GardensErnest Searle23Engineer's LabourerSteyningSussex
20 Dacre GardensArthur Searle21Engineer's LabourerSteyningSussex
21 Dacre GardensJohn Silver44Cement MillerBethnal GreenLondon
21 Dacre GardensCharles French20LabourerLewesSussex
21 Dacre GardensWilliam Hipps19LabourerTollard RoyalWilts
21 Dacre GardensFrancis O Nellis23LabourerBethnal GreenLondon
21 Dacre GardensFrederick Douglas46LabourerBrightonSussex
22 Dacre GardensJohn Pearce47LabourerStroodKent
23 Dacre GardensEdward H Soughton31LabourerSeafordSussex
23 Dacre GardensArthur Williamson44Fitter's MateManchesterLancs
24 Dacre GardensGeorge F Champion28Crane DriverSwinefleetWest Yorks
24 Dacre GardensCharles J Fuller39LabourerHastingsSussex
25 Dacre GardensAlfred H Groves28Gas Engine AttendantUpper BeedingSussex
26 Dacre GardensAlfred H Thompson29ClerkBrightonSussex
26 Dacre GardensHarry A Jeffery34MillerSouthwickSussex
26 Dacre GardensHenry Masterson50Cement MillerIslingtonLondon
26 Dacre GardensGeorge Parker32LabourerArundelSussex
27 Dacre GardensCharles W Keywood26Kiln LoaderBramberSussex
27 Dacre GardensHenry Ashdown54LabourerTonbridgeKent
28 Dacre GardensWilliam A Waghorn40BlacksmithTunbridge WellsKent
29 Dacre GardensHarry Denyer26Gas Plant StokerShorehamSussex
29 Dacre GardensCecil E Thomas19Fitter's ApprenticeSouthamptonHants
30 Dacre GardensStuart Balding32BargeeTunbridge WellsKent
31 Dacre GardensCharles Cherriman29Kiln LoaderHenfieldSussex
31 Dacre GardensRichard Stillaway25Slurry ManShorehamSussex
32 Dacre GardensWalter J Hilder47LabourerWadhurstSussex
32 Dacre GardensWalter H T Hilder25LabourerWadhurstSussex
32 Dacre GardensGeorge J Hilder16LabourerPaddock WoodKent
33 Dacre GardensCharles Dance40PlatelayerSouthamptonHants
33 Dacre GardensRichard Sawyer33Kiln LoaderMaidstoneKent
34 Dacre GardensEdward Ransom28LabourerNewhavenSussex
35 Dacre GardensAlbert Newman36Coal MillerRomseyHants
36 Dacre GardensSydney H Thomas44LabourerWinchesterHants
36 Dacre GardensHerbert S Thomas15LabourerSouthamptonHants
36 Dacre GardensThomas E Gunn37ShunterBrightonSussex
37 Dacre GardensJohn Peachey35Gas Engine AttendantStratford St MarySuffolk
37 Dacre GardensMartin F Budgen23BricklayerBrightonSussex
38 Dacre GardensGeorge Goldsmith38FitterShorehamSussex
39 Dacre GardensJames F J Bridger34Foreman Cement LoaderWorthingSussex
40 Dacre GardensCharles W Upcott56CarpenterTopshamDevon
41 Dacre GardensCharles Boyce48Locomotive DriverBrightonSussex
42 Dacre GardensWilliam Parker40Rotary Kiln BurnerArundelSussex
43 Dacre GardensThomas R Barber35QuarrymanNewhavenSussex
43 Dacre GardensCharles Floyd20Laboratory AssistantActonLondon
44 Dacre GardensRichard F Akehurst37QuarrymanNewhavenSussex
44 Dacre GardensWalter Pepper28Contractor Pile DriverEssex
44 Dacre GardensJames W Parker26Contractor Pile Driver?
44 Dacre GardensGeorge Downey40LabourerExeterDevon
44 Dacre GardensWilliam G Holdbrook31Engine FitterLondonLondon
45 Dacre GardensJ Shepherd40StokerBristolGloucs
45 Dacre GardensI Parkinson29Contractors Clerk of WorksLittle LeverLancs
45 Dacre GardensG Apted50LabourerBrightonSussex
45 Dacre GardensH Linton29LabourerBrightonSussex
46 Dacre GardensGeorge A Akehurst38QuarrymanHeightonSussex
46 Dacre GardensCharles Comber25LabourerPortsladeSussex
47 Dacre GardensG W Lewis34Crane DriverAngmeringSussex
47 Dacre GardensWilliam Kinchell42LabourerSteyningSussex
48 Dacre GardensAlec Bailey36LabourerShorehamSussex
48 Dacre GardensFrederick Wood36LabourerCopthorneSussex

Blue Circle Press Release July 1951

Blue Circle produced a press release on 2/7/1951 to proclaim the successful commissioning of the renovated Shoreham plant. Articles were subsequently produced on 27/7/1951 by various publications, including Cement & Lime Manufacture, The Engineer and Engineering, all more-or-less identical, with various degrees of editing. The following is the transcript of a typescript kept by Southern Area Office. It formed the basis of handouts used in the frequent plant tours offered to schools and the general public. Blue Circle produced this meticulous description in order to represent what they maintained was a state-of-art cement plant of the period. My own annotations attempt to place the details described in their historical context.

New Cement Works at Shoreham - 1951

Capacity 350,000 tons a year

For over 80 years cement has been manufactured at Beeding, near Shoreham-by-Sea, on the South Downs of Sussex, on a site lying between the Shoreham-Steyning road and the river Adur. After the second World War (Note 1), the British Portland Cement Manufacturers, Limited, who operate the Shoreham Works, decided to increase the scale of their activities in this area.

The new works at this site started production early this year, and is now in full operation. The works cost about £2,500,000, and has taken four years to build. It is one of the most up-to-date in the world, and care has been taken in its architectural design to ensure that it is not unsightly. The layout and many of the constructional details of the plant have been designed by the Company's engineering department to ensure easy operation, economy in labour, easy maintenance and reliability of the equipment so that the kilns can be kept running continuously for at least 95% of the year (Note 2), which is essential for the economic production of cement. The new works is highly mechanised, with an elaborate system of conveyors, the main contractors for the mechanical-handling plant being the Mitchell Engineering Company, Limited. Cleanliness has not always been a feature of cement works in the past, but at this works much care has been taken in this respect (Note 3). About £130,000 has been spent on dust-collecting equipment (Note 4), and the plant is almost free of dust. In this respect, as well as in the efficiency of the general layout, the new works is far in advance of older installations.

The main works is built on both sides of a public road, the production section being in the quarry formed by the chalk excavations of old cement works used during the past fifty years. The quarry extends on the opposite side of the road from the old works, over an area some 1,000' long by 800' wide, and of roughly elliptical shape. The chalk cliffs surrounding the quarry are about 180' high at the highest point. The packing plant, rail sidings, coal unloading plant and a block of office buildings are on the site of the old works on the other side of the road and between the road and the river Adur. The two parts of the works are connected by a bridge carrying the cement and coal conveyors. The main span of the bridge is about 130', this span being necessary to allow for future widening of the road (Note 5). A tunnel under the road provides road and rail connection between the two parts.

The kiln building is steel framed, but contains extensive reinforced concrete work. In fact, the structural design of the works was of considerable complexity, involving a wide variety of conditions of loading and of structural shapes, depending on the element under consideration. Each of the main units had its own structural problems - the washmills carry heavy live loads and the mixing tanks a considerable liquid head. Temperature variations are important in the case of the structure of the electrostatic precipitators. The kilns themselves are carried on substantial H-shaped piers of reinforced concrete, which are some 33 ft in height at the higher end of the kiln, giving a pleasing and impressive appearance in the interior of the kiln house. The main stores and bunkers associated with the kiln house have necessitated substantial reinforced concrete work, including retaining walls up to some 30 ft in height. The packing building and office block are both of reinforced concrete. Asbestos cement sheeting has been extensively employed as a cladding in the works, and various sorts of concrete blocks have also been employed; the laboratory and office building is faced with "Tylolean Cullamix", a decorative finish applied with a cement gun.

As the main part of the works is in a quarry, it is screened from view on three sides except for the chimney. In the quarry the works is on solid chalk with a safe bearing pressure of 6 tons per square foot, but on the other side of the road the chalk dips rapidly and in some places it was necessary to drive piles between 15' and 73' long through alluvial silt to chalk.

Briefly, the process of making cement consists of calcining, at approximately 2,650°F, a mixture of finely divided chalk and clay, in the ratio of about 3.8 to 1. To the resulting clinker a small proportion of gypsum is added, which has the effect of retarding the setting time of the cement, which would otherwise be too short. The clinker is then finely ground, to a greater fineness than that specified by British Standard 12: 1947, which requires that, for ordinary cement 90%, and for rapid-hardening cement 95% must pass through a 170-mesh sieve (Note 6). In this country it is usual to use the wet process for mixing the raw materials, as it is considered that a more consistent mixture is obtained for a smaller power consumption, and the dust problem is less of a nuisance.

The works, which has an output of 350,000 tons of cement a year (Note 7), comprises essentially three separate sections, namely, (1) A clay plant at Horton, about 2½ miles distant from the works, at which the clay is dug, made into slurry, and pumped to the works: (2) The chalk quarry, which is at present adjacent to and well above the main works level: and (3) the main works.

Clay Plant

The clay plant is self-contained for the production of clay slurry, and has its own substation. Power is taken from the grid at 11,000 V and transformed to 3000 V and 415 V for motors, 240 V for lighting, and 110 V for portable tools. The clay is dug by a Stothert & Pitt multi-bucket excavator with a capacity of 70 tons per hour, and delivered to a series of 24" band-conveyors. The excavator digs to a depth of 40' to 45' in a dry hole; it weighs about 70 tons, and is mounted on two 4-wheeled bogies moving on an 8' 6" gauge track. The band-conveyors are the ordinary semi-portable surface type, and are moved forward as the cut is extended. The conveyors deliver clay to a 25' diameter Vickers- Armstrongs clay washmill, which is driven by a 200-h.p. motor. The mill has a final drive of crown-wheel and pinion, but in principle it is similar to the mills at the main works for washing chalk. The clay slurry, containing about 70% of water (Note 8), passes through screens around the washmill, and flows to the storage tank. Stones or other material larger than the screen size are retained in the bottom of the mill, and are removed by opening a door in the floor of the mill and allowing the stones to fall into trucks in a tunnel below. The reinforced concrete slurry storage tank is 52' diameter by 10' deep. It has a central "dumpling" on which is a pivoted boom to which stirrers are attached and stir the whole contents of the tank as they rotate.

From the storage tank the clay slurry passes to three adjacent high-pressure three-throw pumps supplied by Messrs. Ernest Newell & Co., Ltd., and then through 2½ miles of 8" pipeline laid underground to the slurry storage tank at the works. The slurry pumps are designed for dealing with slurries at a working pressure of 300 psi. They are of the plunger type, having pistons 10½" diameter with 20" stroke. They operate at 11½ rpm, and are driven by 75-h.p. motors through worm-reduction gears. The 8" pipelines are of mild steel 1" thick, with sleeve-welded joints. Two lines are installed to provide a stand-by and also to allow water to be pumped back from the main works when required; the pumping back of water also serves to wash out the pipeline and prevent an excessive accumulation of adhering clay. The pipes were subjected to a test pressure of 600 psi, and are protected against external electrolytic corrosion by bitumastic and asbestos sheeting. The water supply for washing is taken from a lake formed in an old clay pit (Note 9) adjacent to the new workings, which is replenished with back-flush water from the main works.

Chalk Quarry

The old chalk quarry, in which the new works are laid out, was worked as a single face. The new quarry is at present about 250' above the level of the works. It is intended to work in separate cuts or benches of 30' to 40' over the whole area, so that seven cuts will be made before works level is reached; it is likely to be forty or fifty years before this stage is reached. The chalk is dug by a 3½ cu. yd. Ransome-Rapier electric shovel, and loaded into 9 cu. yd. Aveling-Barford dumpers, holding about 12 to 13 tons of chalk, which carry the chalk to the crusher house. As the working is now in top chalk, which is relatively soft, the shovel is able to dig without assistance, but in lower cuts blasting may be necessary (Note 10).

The crusher is at about 120' above works level. This arrangement gives fairly easy down-grades of working roads from the quarry face, and will be satisfactory for 15 to 20 years when it will be necessary to lower the crusher or to provide a new one at a lower level (Note 11). The crusher (by Messrs. Edgar Allen & Co., Ltd.) is built on to the solid chalk on the face of the old quarry supported on reinforced-concrete foundations. It is a twin-roll claw crusher (kibbling roll), having a capacity of 300 tons per hour of chalk down to 10" cube. It is driven by 100-h.p. motor, with vee-rope drive and spur gearing to 8.44 rpm From the crusher a gravity chute, with chain controls, delivers the chalk to a stockpile of about 2000 tons, or one day's supply, at works level adjacent to the chalk-washing plant.

The Main Works

Clay Slurry

The clay slurry is stored at the works in a reinforced concrete tank 66' diameter and 14' 8" deep, with central dumpling on which a rotating girder is mounted (Note 12). This girder carries an air compressor, and air pipes extending to within 3" of the bottom of the tank provide air to agitate the whole contents. Compressed air is a more efficient means of agitation than the paddles employed at Horton, but it was not economic to install a compressed-air plant there. From the storage tank the slurry is passed to a break-head tank which maintains a constant head above two 6" Wilfley centrifugal sand pumps, either of which is used to pump the slurry to a twin-spoon feeder-box which measures the slurry to the chalk washmill. The spoon-feeder is started through a relay system operated by an Adequate weigher mounted at the delivery end of the 30" chalk band-conveyor to the washmills. The weigher integrates the weight of chalk delivered, and after each 10 tons, a relay system operates, starting the clay spoon-feeder to deliver a burst of slurry for a predetermined period, which can be adjusted by the works chemist to achieve the desired chemical composition of the finished slurry.

Chalk Washmills

From the pile below the crusher the chalk is lifted by a 11½-tons Carruthers electric grabbing crane situated on a reinforced-concrete platform, and put on vibrating feeders which deliver it to 30" band-conveyors feeding the chalk washmills. These reduce the chalk/clay mixture to a fine slurry and remove flint and sand.

There are two rough washmills for chalk, one secondary washmill and three screening washmills. The mills are arranged at different levels so that there is gravity flow between the various stages. The rough mills are used alternately and consist of reinforced concrete tanks, 35' diameter, in which arms revolving about a fixed king-post carry harrows that break down the chalk. The floors of the mills are lined with granite setts, and the walls below the screens are protected by short lengths of bullhead rails laid as bricks, in courses, keyed and bonded. Around the periphery of the rough mills the slurry passes through vertical grids with 1" and ¾" gaps, and thence along troughs to the secondary mill. This mill is similar in design to the rough mills, but has 4-mm by 1½ mm mesh sieves around its periphery. Slurry passing through these sieves is carried by troughs to the screening mills, which are the same diameter but lighter than the rough mills with splasher-plates instead of harrows mounted on the rotating arms. In these mills 32-mesh woven-wire screens are arranged around the periphery. In the secondary and screening mills, the full circumference is used for screening the slurry, but in the rough mills only 85% is used, solid plating being provided below the entry chute to prevent the slurry from being washed out immediately. The greater part of the breaking down of the chalk is done in the rough and secondary mills; the screening mills do some breaking down but their purpose is to screen the slurry to the required fineness.

All these mills, which are of very strong construction, were supplied by Messrs. Head, Wrightson & Co., Ltd. The drive comprises a motor and totally enclosed reduction gear mounted on a steel bridge over the mill, with a final drive of spur-wheel and pinion. The drives were supplied by Messrs. David Brown & Co., Ltd. The rough mills and the secondary mill are driven by 350-h.p. Metropolitan-Vickers slip-ring motors operating from a 3-kV supply; the 100-h.p. motors for the screening mills operate from a 415-V alternating-current supply. In all cases the speed of the mills is 10 rpm.

In earlier mills, the practice was to install the driving motor at some distance from the mill and to transmit the drive through a long counter-shaft and machine-moulded bevel gearing, which caused vibrations and consequent wear and tear. In each of the present machines, the driving motor is mounted on an upper bridge spanning the mill, and is connected to a combined helical and bevel double-reduction gearbox. The vertical output shaft of the gearbox is coupled to the pinion shaft of the final reduction gears, which are machine-cut spur gears. The pinion-shaft bearing is mounted on the lower bridge across the mill, which also carries the top location for the king post of the washmills. The use of two bridges serves to insulate the motor and gearbox from any vibrations generated in the mill. The first reduction gears are totally enclosed and are lubricated by an oil spray. The spur wheel is mounted on the rotating-harrow frame, which consists of a braced cruciform structure of rolled-steel joists from which the harrows are suspended by chains. Hand-operated overhead travelling cranes are provided above each level for maintenance work.

Removal of Flints

The chalk contains about 5% of flint varying in size from 6" ring to fine sand, which is removed during the washing process. From the rough mills the flints are periodically discharged, through a door in the floor, into a concrete hopper under each mill. From these hoppers the flints are delivered by jigger-feeders on to sloping belt conveyors which carry them up to a chute feeding a rotary washer, 24' long by 4' 6" diameter and 5° slope, of the contra-flow type; the flints enter at the low end and the wash-water flows in the opposite direction. The flints are carried up through the water by helical lifters, and any chalk adhering to the stones is removed. At the top end of the washer a screen plate separates the flints into those over and under 2", each size being discharged on to a separate band-conveyor. The larger flints are suitable for use in potteries, and are taken directly to rail wagons or to a stockpile. The under-size material is taken to another storage area, for use as rubble.

From the secondary mill the smaller flints ("beach") which have escaped from the rough mills are discharged continuously through a duct in the floor to an elevator delivering to a rotating screen with ¾" diameter holes. The flints larger than ¾" may be returned to the mill, and the smaller material is washed in a washing-screw before passing to the storage bins. The larger flints are returned to the secondary mill to help in breaking down the very hard chalk; that is they act as grinding media. From the screening mills the fine sand (Note 13) passes continuously through ducts in the floors of the mills to small sumps. Here extra water is added, and a 2" Wilfley centrifugal sand-pump delivers the resulting slurry to a Dorr-Oliver bowl-and-rake classifier. This machine extracts all grit larger than 100 mesh, this being discharged to dump. The fine material, which is mainly chalk, is delivered separately as a thin slurry, and is pumped to a Dorr-Oliver thickening tank, which also receives the wash water from the flint and "beach" washers. The thickened slurry is pumped back into the rough mills, and the clear water from the top of the thickener is re-circulated for use in the washers and the screening-mill sandpits. About 6 tons of thickened slurry are returned to the tank for every 100 tons of chalk passing the wash-mills. This plant may seem to be rather complicated and expensive, but it produces clean flint which is a saleable material with a minimum of waste and sand residue, and all usable material is kept in the production circuit. Without this plant it would be difficult and costly to dispose of the sludge from the flint and grit washing plant, and it is possible to wash down the whole area of the washmill plant without the risk of blocking the storm-water drains.

Mixing Tanks

From the screening mills the slurry is pumped by one of two 6" Wilfley centrifugal sand-pumps to any one of four reinforced concrete preliminary mixing tanks with diameter tapering from 24' to 23' 7" and 54' 6" high with conical bottoms. In them the slurry is thoroughly mixed by blowing air into each tank in turn from a central air pipe; electrically-operated sequence valves control the distribution of air to each tank. Each tank fills in four hours; hourly tests on the incoming slurry provide information to adjust the clay dosage rate at the washmills so that the filled tank has composition close to the target value. It is the practice to fill one mixer completely with slurry and, when it is full, to alter slightly the proportions of chalk and clay entering the washmills so that a slurry of high-carbonate content alternates with one of low-carbonate content. From the preliminary tanks the slurry is pumped by 8" Wilfley centrifugal pumps, protected by break-head tanks, to the final mixers, taking calculated amounts of slurry from a pair of preliminary tanks, one of which is slightly above composition target, and one slightly below. This allows control of the composition of the final slurry with a high degree of accuracy (Note 14). A final composition check is made before the slurry is allowed to flow by gravity to the storage tanks. The final mixing tanks are similar in design to the preliminary mixing tanks, but are 27' 6" to 27'1" diameter and 76' high. Beneath these tanks are the kiln-feed slurry-pumps. Pneumatically-operated depth indicators are fitted to each tank to give an accurate and visual indication of the depth of slurry in the tank (Note 15).

Slurry Storage Tanks

The three storage tanks for the finished slurry are similar to the clay-slurry storage tank previously described. From these tanks the slurry is pumped to a tank over the kilns, at a rate in excess of that used by the kilns, the excess returning by gravity to one of the storage tanks. Three Edgar Allen slurry-pumps are provided for this purpose, one being a standby. These pumps are of the three-throw plunger type, with 12-in, plungers and 15" stroke, and have a working pressure of 150 lb. per square inch.

Kilns

The slurry is calcined in two Vickers Armstrongs rotary kilns, housed in a steel-framed building 500' long, 67' wide, and 65' high at the eaves. The kilns are each 350' long by 10' diameter (Note 16) with an enlarged burning zone 11' 6" diameter, rotate anti-clockwise when viewed from the lower end, slope at 1 in 24. Slurry is dried in the upper third of the kiln, after which the feed temperature rises rapidly, reaching a peak 2,650°F (Note 17) in the burning zone where clinker is formed. The residence time of the feed in the kiln is about 3½ hours. Each was designed to produce 23 tons per hour of clinker at a fuel consumption of not more than 23% standard coal (12,600 B.Th.U. per pound - Note 18) and to operate continuously for 95 to 96% of the year.

The kilns are constructed of 1" steel plates over a length of 110' at the lower end (except for the 1¼" renewable nose ring), the rest of the kiln plates being ⅞" thick. The diameter at the burning zone is increased to 11' 6"; the nose-ring castings are of heat-resisting steel. The kilns were constructed in sections at Messrs. Vickers Armstrong's works, with plate joints welded by the Union-melt process, the kiln sections being connected at the site by riveted butt straps (Note 19). They are lined with high-alumina bricks.

The kilns are supported on six tyres of 45-ton alloy steel, each running on two large rollers, the spindles of which run in water-cooled self-aligning bearings fitted with integral oil lifters for distributing oil on to the bearing surfaces. The bearings are supported on cast-iron bedplates and the side thrust of the rollers is resisted by steel castings, retained by long steel tie-bolts passing through the bedplate. The reinforced-concrete kiln piers supporting the bed-plates each carry a vertical load of 200 tons, and are of H-section to resist heavy longitudinal and transverse forces from the kiln.

An improved arrangement for resisting the down-ward thrust of the kilns (as the result of the slope) has been used at Shoreham. Hitherto it has been customary to take the thrust partly on a roller mounted on a vertical spindle and engaging with the side of one of the tyres, and partly by "cutting" the rollers which support the tyres, i.e., by inclining the axis of the rollers to the axis of the kiln, so that the rollers tend to force the kiln uphill. This practice resulted in undue wear on the rings and rollers, as their faces were not in contact over their full width and, further, it was difficult to ensure the same amount of cutting on every roller. To overcome this difficulty, a further thrust roller has been introduced on an adjacent bedplate, but to compensate for the expansion of the kiln shell—which amounts to about 10¾" (Note 20) for the whole kiln—this second thrust roller is mounted on a counterbalanced slide, so that the roller follows the movement of the kiln and takes its fair share of the thrust at all times. Under certain conditions, there is a tendency for the kiln to creep uphill, and to limit this movement another fixed thrust roller is provided and arranged to operate on the uphill side of a tyre—in the case of Shoreham, No. 5 tyre. The total weight of each kiln, with refractory lining and material passing through, is about 1000 tons.

Each kiln is driven by a 150-h.p. variable-speed motor, with a speed range of 592 to 230 rpm, operating on a 3-kV supply, through a V-rope drive to a reduction gear, and then through further reduction gears fitted in the drive bed of the kiln, and through a girth gear, which is attached to the kiln by tangent plates. The kilns rotate at from 0.67 to 1.33 rpm.

The slurry from the feed pumps is received in a distribution box at the top of the kiln house, whence it divides to two variable-speed spoon feeders which deliver it into the upper end of the kilns. The slurry flows down the kilns and the hot gases, produced by burning pulverised coal at the lower end, flow upwards. At the upper end of the kiln, curtain chains act as heat exchangers between the hot gases and the slurry, and catch much of the dust that would otherwise escape from the kiln (Note 21); the flow of slurry down the kilns is assisted by festoon chains.

From the lower end of the kilns, the clinker is discharged to rotary coolers (supplied by Messrs. Ernest Newell & Co., Ltd.), 90' long by 9' diameter (Note 22), arranged under the kilns and supported on two tyres with one fixed-position thrust-roller resisting all down thrust. The coolers slope at 1 in 20. The upper half, i.e., the hot part of the cooler shell, is lined with firebrick and, except for the first quarter of the length, lifters are arranged around the inside periphery so that the clinker may be lifted up and cascaded down through the cooling air. The first two rows of lifters are of heat-resisting cast steel, the next five of heat-resisting cast iron, and the remainder of mild steel. This system provides an equally distributed curtain of falling clinker in order to obtain efficient cooling from the incoming air; the air is heated by this for use as secondary combustion air in the kiln; thus the heat in the clinker is largely reclaimed to improve the efficiency of the kiln. The clinker enters the cooler at about 2000°F and has a temperature of about 230°F (Note 23) when it is discharged. The coolers rotate at 1½ rpm, and are driven by fixed-speed 50-h.p. motors operating from a 415-V supply, the drive arrangement being similar to, but smaller than, the kiln drive.

The air passing up the coolers provides secondary air for the combustion of the pulverised coal. The combustion gases and steam and CO2 driven off from the slurry pass up the kilns and are exhausted through flues to two Sturtevant electrostatic precipitators which extract the fine particles from the gas (Note 24). Each has three electrode chambers, which are arranged so that any one chamber can be shut down for cleaning and maintenance while the other two are in operation, this arrangement being made to ensure that the precipitators operate during the full kiln working time, as it is not necessary to wait for a kiln shut-down before the precipitators are overhauled. The flue gases are passed upwards through vertical receiving electrode tubes, through the centre of each of which runs a wire discharge electrode. The potential difference between the discharge and receiving electrodes is about 50 kV, the high-tension supply to the discharge electrodes being provided by mechanical rectifiers. The dust collected on the receiving electrodes is removed by rapping rods, operated by heavy spring-loaded hammers driven by a camshaft; it is discharged through a hopper and removed by a screw-conveyor. By this means, the dust content of the gases passing out of the chimney is restricted to less than 0.4 grains per cubic foot (Note 25). The dust that is collected is returned to the kiln (Note 26). A by-pass is also provided whereby the kiln gases can be taken direct to the fan. To reduce the expansion of the reinforced-concrete structures in which the precipitators are housed, under the high temperature of the exhaust gases (400 deg. F.), the walls are lined with brickwork and a 1" air cavity is provided between this lining and the concrete. For the same reason, the roofs of the chambers and flues are lined with hollow tiles. A steel platform, for giving access to the dust-testing points on the exit flues, spans between the precipitator housing and the steel framework of the kiln house. To allow free expansion of the precipitators, the support points on the precipitator are provided with steel roller bearings in grease-filled boxes.

The gases are drawn through the precipitators by 100" damper-controlled Keith Blackman induced-draught fans (one to each kiln), which discharge into a common chimney 300' high. The fans are driven by two-speed Metropolitan Vickers 170/52 h.p. motors operating from the 3-kV supply. The fans have been developed to suit cement works practice and for easy servicing and removal of the impellers, quickly-detachable fan doors and panels are provided for the rapid cleaning or changing of the impeller, which can be done without interfering with adjacent flues. The impeller itself is attached by bolts to a flange on the shaft.

The chimney is of reinforced concrete, and tapers from 23' 1" outside diameter and 9" thick at the base to 13' diameter and 5" thick at the top. It is lined throughout with 4½" of brickwork, with a 4" air-space between the concrete and the lining. The top 15' is built entirely of brickwork, because experience has shown that kiln gases damage the top of reinforced concrete chimneys fairly rapidly while brickwork is not affected so badly, and it is much easier to renew brickwork if this should be necessary.

The kilns are fired with pulverised coal, which is ground in four No. 18 Atritor machines supplied by Messrs. Alfred Herbert, Ltd. Each machine is driven by a 150-h.p. English Electric Company motor operating on a 3-kV supply. Each is fed from a coal bunker in the kiln house. It is possible to operate each kiln at a reduced rate on the output from one machine so that it is not necessary to stop the kiln if one of the Atritors needs attention. The hot air for drying coal in the Atritors is drawn from the kiln-hoods through cyclones, which remove any clinker dust in the air stream The Atritors are under the floor at the firing end of the kiln. The two Atritors supplying No. 1 kiln are fed through 5-cwt. batch weighers, to keep a check on the coal consumption. Hot air for drying the coal in the Atritors is drawn from the kiln hoods, through cyclones which remove any clinker dust arising from the discharge of hot clinker down the chute to the coolers. Over-size coal rejected by the Atritors travels by an underground screw conveyor and an elevator to the coal store.

The kiln control and indicator panel is supplied by Contactor Switchgear, Ltd. It is over 18' long and is mounted on "Silentbloc" pads; it controls the following main motors: 170 h.p. kiln drives, 170 h.p. two-speed induced draught fans, 150 h.p. coal pulverisers, 50 h.p. coolers, auxiliary d.c. motors for the slurry spoon feeders and Atritor feeds. All plant connected with the kilns, coolers and coal mills is controlled from this panel; on it also are temperature indicators and recorders, draught indicators, slurry-feed indicators, and all other controls and information required by the burner. Flashing lights are mounted on the top of the board and are duplicated at the back end of the kiln to indicate that the cement slurry is being delivered to the kilns. In the event of a failure of supply, alarm is given by a hooter.

Mention should be made of the contactor switchgear controlling the two-speed, 170/52 h.p. induced draught fan motor. Provision is made for ensuring that the motor is started on the low-speed winding, and a time delay relay further ensures that the low-speed contactor remains for an adjustable starting period of 40-60 seconds, whilst another timing relay, adjustable from 0-30 seconds, is incorporated for the change from low to high-speed running.

Above the firing floor are the coal-storage hoppers for the Atritors. These are of reinforced concrete and provide storage for about 700 tons of coal. Above these hoppers are the coal conveyors and the coal crushing and screening plant. Also over these hoppers there are the main water-storage tanks with a capacity of 51,200 gallons.

Transport of Clinker

From the coolers the clinker is discharged on to either one of two 32" Edgar Allen shaker-conveyors. The lowest 2' 6" of the cooler consists of a 6" mesh grid which discharges the oversize clinker to a hopper-bottomed chute, from which it is periodically removed as necessary and taken to the clinker crusher pit. The clinker passing through the cooler grids is carried along the shaker-conveyors, which near the discharge end are double-decked The upper deck, acting as a screen, separates the material larger than 1¼" and passes it to the crusher pit. The material smaller than 1¼" is passed to a 24" band-conveyor; if the band-conveyor is under repair all the clinker from the coolers can be taken to the pit in the clinker store.

The band-conveyor system is arranged so that the small clinker can be discharged into the main clinker store or conveyed directly into any one of the grinding mill hoppers. It delivers on to a travelling shuttle belt conveyor, running on rails, which can deliver clinker to the store bunkers through cylindrical chutes arranged at intervals along the floor of the conveyor annexe. Dust extractors are provided over each chute (Note 27). In its most forward position, the belt conveyor can deliver clinker on to another conveyor going off at 90° and discharging through a small chute and a Redler conveyor directly to the store hoppers feeding the grinding mills, which are in a building at right angles to the store building. By using the Redler conveyors to discharge the clinker into the feed hoppers, it is possible to enclose that part of the hoppers which is inside the mill house and thus prevent a dust nuisance. Clinker from the store can be fed to the hoppers by an overhead grab crane (Note 28).

The oversize clinker is taken by the store crane to a reinforced concrete hopper, from which it is fed to an Edgar Allen swing-jaw granulator by a Ross chain. The crushed clinker falls into another pit, from which it is taken by the crane to the main clinker store. This arrangement for dealing with over-size clinker has the advantage that it is not moved by a band-conveyor at any stage; the large pieces of clinker retain their heat for a considerable time, and can cause considerable damage to the rubber bands. All the clinker in the store, and going directly to the mill house, is of a suitable size for feeding to the grinding mills.

Store Building

The main store building is 500' long, 75' wide, and from 59' to 62' to the eaves, and provides storage for 15,000 tons of clinker, 1500 tons of gypsum and 5500 tons of coal. These materials are stored in depths of 40', 18', and 16' respectively. The retaining walls are of reinforced concrete, and are formed as cantilever buttresses with walls spanning between them. The roof and crane track are carried on steel stanchions, and there is a clear space between the buttresses of the retaining walls and the steel stanchions in order to avoid deflection of the walls causing distortion of the crane track. Two 10-tons Stothert & Pitt overhead travelling cranes are installed. The store building is parallel to the kiln building, with an annexe about 10' wide between the two buildings. In this annexe are all the distributing conveyors for coal, gypsum, and clinker. The cement conveyors to the packing plant are also in this annexe, together with several Visco dust plants at the transfer points on the various conveyors. At one end of the store building there are four elevated reinforced concrete clinker hoppers each with a capacity of 260 tons, and four 100-tons gypsum hoppers, from which the clinker and gypsum are fed to the four grinding mills. Below the clinker and gypsum hoppers there are band-feeders with weighing and constant-feed control gear supplied by Adequate Weighers, Ltd and the British Thomson-Houston Company, Limited. The weighing mechanism weighs the amount of material passing over a given length of belt and records it in tons per hour. A separate weighbeam, which is provided with a poise weight to balance at the desired feed rate, operates electrical switches which control a ratchet mechanism altering the speed regulation of the feeding-conveyor motor. so that a constant flow of material is fed to the mills.

Grinding Mills

There are four grinding mills, two with 1200-h.p. motors, one 800-h.p., and one 400-h.p. (Note 29) All the mills are centrally driven at their discharge ends. The motors and gear-boxes are in a separate building. Grinding is effected by steel balls of different sizes. The mills are all divided into compartments to separate the different ball sizes, separated by slotted diaphragms. They are fed with clinker and gypsum by scroll-drum feeders. The mill shells are water-cooled.

The two 1200-h.p. mills were supplied by Vickers- Armstrongs, Ltd. They are 8' 4½" diameter by 45' long, divided into four compartments with chambers of about 30%, 20%, 30%, and 20% of the length of the mill. They are fed through a 5 ft 3 in diameter, three-scroll drum feeder. The first two chambers are lined with hard alloy-iron plates, and the third and fourth chambers with hard white cast-iron bars. The charge of these mills is about 76 tons, and they rotate at 20.5 rpm. The 800-h.p. mill was supplied by Messrs. Ernest Newell & Co., Ltd., and is 7' 6" diameter by 40' long. It is divided into three compartments with chambers of about 30%, 40%, and 30% of the length of the mill. It is fed through a 4 ft diameter, two-scroll drum feeder. The first two chambers are lined with hard alloy-iron plates and the third chamber with hard white cast-iron bars. The charge of this mill is about 52 tons, and it rotates at a speed of 21 rpm. The 400-h.p. mill, originally supplied by Ernest Newell & Co., Ltd., is 6' diameter by 29' 4" long, and was transferred from the old works (Note 30). It is divided into three compartments, and rotates at a speed of 25 rpm The mill has been re-conditioned, and converted from a peripheral discharge to a trunnion discharge in order to conform to the arrangement of the new works.

The two 1200-h.p. mills are driven by Metropolitan-Vickers auto-synchronous induction motors through totally enclosed double-helical gear-boxes supplied by Turbine Gears, Ltd., and are equipped with barring gears and motors giving very slow rotation to facilitate maintenance work. They have pressure relay switches on the oil supply system which automatically cut out the main-drive motor if the pressure in the oil supply to the gears falls below 15 lb. per square inch. The 800-h.p. mill is driven by a Metropolitan-Vickers auto-synchronous induction motor through a totally enclosed double-helical gear-box supplied by Messrs. David Brown & Co., Ltd.

Dust Collection

To remove water vapour that may arise from the gypsum and to keep the plant dust-free, air is drawn continuously through the mill and filtered in a dust plant. There are five large Visco dust-collecting plants installed in the grinding-mill house; two deal with the feed and transfer points on the clinker and gypsum conveying system from the hoppers to the inlet end of the grinding mill, and the other three are used for venting the outlet hood of each mill and the cement conveyor system. As there is a good deal of dampness in the air drawn from the outlet end of the mill, these three plants have pre-heated scavenging air equipment in order to keep the filter-stockings clean and dry.

Cement Storage

The cement from the mills is discharged into either of two Redler conveyors, which deliver on to 24" band-conveyors extending to the top of the main storage silos. At the top of these silos a further series of Redler conveyors is used for distribution (Note 31). Twelve reinforced concrete storage silos are provided each having a capacity of 1250 tons. They have an inside diameter of 26' 6" and are 60' high from the base. The silo bottoms are about 10' above ground level; four outlets are provided from each silo to conveyors below. Under the silos there are Redler conveyors which carry the cement through a tunnel under the coal store and deliver it to an inclined band-conveyor in the annexe between the kiln and store buildings. Compressed air is used to extract the cement from the silos. Rubber-diaphragm valves are used to control the supply of cement from the silos to the Redler conveyors. A 30" inclined band-conveyor in the annexe carries the cement up to the bridge, across the road, and discharges it into either of two 900-tons silos at the packing plant, one of which is used for ordinary cement and the other for rapid-hardening cement. These silos are similar in design to those for the main storage, but 45' high.

Packing Plant

The cement is drawn from the packing plant silos as required for the packing machines, which are in a five-story building adjacent to the silos. The extraction chutes from the silos have perforated tubes in the bottom through which air is blown to aerate the cement. These chutes discharge into two 24" screw conveyors, each feeding a slow-running central discharge elevator with a capacity of 125 tons per hour. The elevators were supplied by Messrs. Ernest Newell & Co., Ltd., and the silo extraction gear by Messrs. F. L. Smidth & Co., Ltd. Each elevator discharges to a revolving screen in which any foreign matter, air-set lumps and nibs are removed, and the cement passes to surge hoppers over the Fluxo packing machines. The rate of extraction of cement from the silos is automatically controlled to suit the requirements of the packing machines. There are two twelve-spout Fluxo packing machines supplied by F. L. Smidth and Co., Ltd, each capable of filling 120 tons per hour into 1-cwt. bags. Each machine comprises a central rotating hopper into which the cement is fed from the surge hopper by a pneumatic feeder. Twelve symmetrically-arranged spouts are connected through short lengths of flexible tubing to the hopper; by means of clamps the flexible tubes are used to control the inlet of cement to the spouts. The spouts are supported on cradles suspended on weigh-beams, the fulcrums of which are carried on arms projecting from the rotating hopper. The other ends of the weigh-beams carry adjustable balance weights, which are pre-set to the weight to which the bags are to be filled. The machines are completely automatic except for putting the paper bags on the spouts. The compressed air for cement extraction and packing is supplied by Alley & McLellan compressors. The paper bags are stored on a floor over the loading bays, to which they are elevated from ground level by a slat type elevator.

The machine is controlled by a single operator, who feeds a bag on to a spout as it passes, where it is retained by a clip. As the bag passes away from the operator, a roller on the cradle engages with a fixed cam and releases the clamp on the flexible tube, whereupon cement flows into the bag until the pre-selected charge has been filled. At this point, the weigh-beam drops and trips the clamp on the flexible tube, cutting off the cement flow. When the bag reaches the discharge point, another cam and roller cause the clip retaining the bag on the spout to be released, and the spout, which is hinged, drops the bag on to a discharge turntable and thence to a laminated conveyor, returning immediately to its normal position. If, however, the bag has not at this stage filled sufficiently to drop the weigh-beam, the discharge. roller does not engage with the cam and the bag is carried round for another cycle. A beating mechanism below the feed hopper ensures even filling.

In order to provide the correct weight of cement, it is essential for the head of cement above the spout to be maintained constant. The level of cement in the feed hopper is, therefore, controlled by float-operated solenoids which operate valves shutting off the supply from the feeder. Similar float-operated controls in the surge hoppers shut off the air supply to the packing silos and thus stop the flow of cement when the level in the surge hopper exceeds a certain value. There is inevitably a certain amount of spillage with machines of this type; this is collected in a hopper below the Fluxo machine and conveyed back to the elevator. A fan and air-filtering system on a floor above is also provided for each machine and connected to all points where dust may be produced.

From the laminated conveyor of the Fluxo machines, the filled bags are carried by band-conveyors to either road or rail loading bays. There are three retractable conveyors which can be taken out over lorries and deliver the bags to the place where they are to be stacked. For rail loading the bags are delivered to a turntable on a platform between two rail loading tracks; from this turntable they are removed and stacked in wagons by means of sack barrows. The packing and loading machinery are arranged so that the bags from either packing machine can be delivered to either road or rail loading dock. Both by road and rail an average loading rate of 100 tons per hour has been maintained.

Receiving Coal and Gypsum

Coal and gypsum are delivered by rail and unloaded by a combined wagon-tippler and weighbridge which discharges onto a reciprocating-tray feeder which discharges on to belt conveyors passing through the bridge crossing the road. A magnetic separator removes any "tramp" iron. The capacity of the coal conveyor system is 120 tons per hour. The wagon tippler is enclosed in a building in which a dust-extraction plant is provided to suppress the spread of coal dust. At the top of the gantry, in an annexe above the coal bunkers at the road end of the kiln building, the coal is delivered either directly to the coal store or through a ¾-in screen to a Redler conveyor which discharges into the four coal bunkers in the kiln house; the total capacity of these bunkers is 700 tons. The over-size material from the screen in the kiln house is discharged into the coal crusher, and thence to the same Redler conveyor. A return conveyor, fed by the store crane, is provided to carry coal, when necessary, from the store back to the gantry conveyor for feeding to the coal bunkers in the kiln house. The gypsum follows the same route until it reaches the top of the coal hoppers, where it is transferred to a conveyor running through the annexe and is discharged into the gypsum store. A coal-crushing and screening plant has been installed to deal with coal passing to the store, and no material over ¾" is passed to the coal-grinding machines.

Power Supply

The power supply to the works is afforded by duplicate 33 kV lines of the South-Eastern Electricity Board's network. Two 5 MVA, three-phase, delta/star O.N. cooled outdoor transformers step down the voltage to 3kV. These transformers are fitted with on-load automatic tap-changing equipment, which permit a voltage variation of plus 6% to minus 9% in ten 1.5% steps. Protection on the 33kV line is taken care of by neutral point displacement with overload and earth leakage. Fault-throwing switches are incorporated, which, in the event of a fault, intertrip the 3 kV transformer oil circuit breaker, preventing re-closure whilst the system is unhealthy. The clay quarry being approximately 3 miles from the main works, an 11 kV supply is brought in by means of an overhead line "spurred off " the local S.E.E.B.'s ring main. One 600 kVA, three-phase, delta/star O.N. cooled outdoor transformer steps down the voltage to 3kV. The supply of both works is metered by duplicate integrating watt-hour meters with maximum demand indicators. The total maximum demand when the works are in full production will be of the order of 5500 kW. In the manufacture of cement continuity of supply is extremely important, so that the 3 kV feeder system is split and duplicate supplies are afforded to the various substations, as illustrated in the line diagram below, thus ensuring that under ordinary circumstances a local power failure cannot shut down both kilns.

The whole of the 3 kV switchgear comprises some fifty-two single bus, air insulated, vertical plugging equipments, having a rupturing capacity of 100 MVA. The feeder and transformer oil circuit breakers include spring closing, whilst for the 3 kV motor circuits solenoid operation is employed.

In the main substation there are three switch-boards, comprising one fourteen-panel and two seven-panel boards. It will be noted from the line diagram that the incoming feeds from the two 5 MVA transformers connect to the fourteen-panel switchboard, one on either side of a bus section switch, which, under normal operating conditions, remains closed. From this board outgoing feeders in duplicate afford supply to the two seven-panel kiln switchboards and also to the grinding mill and washmill substations, which have been mentioned earlier.

The transformers affording the L.V. supply (415 V, three-phase, 50 c /s, earthed neutral system) are of 600 kVA capacity and are positioned at the various substations.

The principle of sectionalising the L.V. network to safeguard continuity of supply has been incorporated in all the main switchgear. A seven-panel airbreak truck switchboard of 25MVA rupturing capacity, with H.R.C. air circuit breakers, is positioned in the main sub-station. It controls the incoming feeders from the two 600 kVA step-down transformers, two 2 by 0.22 square inch outgoing feeders to a main switchfuse board, one 2 by 0.25 square inch outgoing feeder to the packing plant, and one 2 by 0.15 square inch out-going feeder to the kiln house, together with one 1200 A bus section switch. The sub-distribution switchgear throughout the works comprises over twenty fuse switchboards, some with off-load isolators of 800/1000A capacity, together with some seventy distribution boards.

About 200 oil-break starters have been supplied for the L.V. motors, which include direct-on-line units for squirrel-cage motors and stator/rotor units for slip-ring motors. The larger motors up to 1200 h.p. have rotor control by means of liquid starters.

All 3 kV motors are protected against single phasing, overcurrent and earth leakage by thermal relays, together with direct-acting overload trip coils with fuses as back-up protection.

Motors

In order to obtain a satisfactory overall power factor, auto-synchronous induction motors incorporating pedestal mounted cartridge ball and roller bearings have been adopted for driving the large grinding mills. Two are rated at 1200 h.p., 970 kVA, and one 800 h.p., 600 kVA, designed to give a power factor of 0.95 leading.

All the 3 kV motors are of the standard drip-proof pattern.

There are, however, two somewhat special drives associated with the kiln. One is that for the induced draught fan, which is an 8/12-pole machine with an output of 170/52 h.p. at 725/490 r.p.m.; the weight of the impeller is 3700 lb with a radius of gyration of 2.62ft.

The other, the main kiln drive, is a 170/68 h.p. motor with a speed range of 692/230 r.p.m. By means of rotor resistance, close regulation of speed is obtained from normal down to 50% of full load speed against a constant torque equivalent to not less than 150 h.p. at full speed.

The subsoil over the greater part of the works site is hard chalk, except on the west border, where alluvial mud is to be found adjoining the banks of the river, and tests taken showed that this was the only satisfactory position for the siting of the main earthing point. Four 6 in diameter C.I. pipes 10 ft long were therefore driven in the ground at 10 ft spacing, and to provide a duplicate earthing system each pair of electrodes was joined together by copper strip, and connected by lightly insulated cable to the earth bar in the main substation. This arrangement ensures a resistance of less than 1 ohm for each pair of electrodes, thus enabling the necessary periodical tests to be carried out whilst still ensuring adequate earth continuity.

As a safeguard against the predetermined maximum demand (M.D.) being exceeded, "Ideal" load-control meters have been installed. Each meter has an indicator of normal construction registering the actual M.D. and also incorporated is a second M.D. indicator which is driven by a synchronous motor at a speed proportional to the value of the predetermined M.D. Should the actual M.D. exceed that corresponding to the setting of the predetermined load, except within the first three minutes of each (thirty minutes) period, then a contact device closes enabling audible or visual warning to be given to the load controller.

General

Between the kiln building and the washmills there is a long building 50' wide in which are the substation, carpenters' shop, blacksmiths' shop, fitting shop, and general stores. The building has two stories at the substation end, with electricians' shop and offices on the second floor. The shops are so equipped that nearly all the general maintenance work of the factory can be dealt with.

The water supply is from two boreholes, each delivering 12,000 gallons per hour to two 25,600-gallon header tanks, carried on a floor over the coal bunkers, and to a 6" ring main around the works. The water used for cooling purposes is recovered and pumped to the clay plant. The works has also its own sewage plant.

An office building accommodates the laboratories, office, and canteen. On the ground floor are chemical and physical testing laboratories, first-aid room, men's washrooms, and locker rooms. The first floor is used as offices, and the top floor as dining rooms, kitchen, etc. The main dining hall is arranged so that it can readily be used for social functions.

As the incoming and outgoing goods trains will shortly operate only between midnight and 6 a.m., extensive railway sidings have been installed, two 165-h.p. Ruston Diesel locomotives being provided for shunting.

Generally the buildings are of steel-framed construction, the main exceptions being the office block, packing plant, substation, and one end of the kiln and store building which have reinforced concrete frames. The walls of all buildings are either precast concrete blocks or asbestos-cement sheets. Concrete roads have been laid throughout the works, and a storm-water drainage system has been installed to discharge to the river.

Messrs. Oscar Faber & Partners were the consulting engineers for the civil engineering work. Mr. G. A. Jellicoe, supervised the architecture. The main contractors for the civil engineering works were Messrs. John Laing & Co., Ltd. The sub-contractors for the reinforced concrete work were Messrs. Bierrum & Partners, Ltd., and for the structural steelwork Messrs. Redpath, Brown & Co., Ltd. The civil engineering work at the clay plant was done by Messrs. J. L. Kier & Co., Ltd., and the mechanical handling plant at the works by Mitchell Engineering, Ltd.

The arrangement, design and erection of the plant were carried out by the Works Engineering Department of the Associated Portland Cement Manufacturers, Ltd.

Filter Presses on kiln C3

The 1959 Engineer article describes the kiln C3 slurry filtration system as the first in Britain, although the vacuum filtration system at Billingham had been in use for nearly 30 years. It was however certainly the first to use plate-and-frame pressure presses.

The project started in January 1955, and was completed 17 months later, indicating that it was commissioned in June 1956. There were three presses, each with 80 4 ft square plates, operating at 120 psi (827 kPa). Each was said to produce about 10 tons of cake per batch. The moisture content was said to be 18-19%, and 17-18 batches were completed every 24 hours, indicating a mean cycle time of around 82 minutes. Since cake of 18.5% moisture content has a density of around 2053 kg/m3, cakes of effective dimensions 46.5 × 46.5 × 1.75 inches would weigh 127 kg, and 80 of these would yield 10.19 tonnes of cake. The kiln averaged 235 tonnes/day of clinker, and probably made as much as 265 tonnes/day at peak production, requiring 539 tonnes/day of cake. Since the three presses were producing 540 tonnes/day, there was little overtaking capacity, and occasional down-time for filter cloth cleaning and replacement would have limited the kiln production.

Nylon filter cloths had been selected, and these were said to last for about 2000 cycles each, or 3000 cycles after repairs.

NOTES

Note 1. Planning for the new plant actually began before WWII, which explains why much of the technology was that of the 1930s.

Note 2. The best annual runtime was 98.69%, but the median value, affected by market condiotions, was 94.06%. The mode value was 95.6%.

Note 3. A high standard of cleanliness was a noted feature of the plant, at least up to the end of the 1970s. A favourite exhibit was the immaculate aquarium and mirror-like floor in the finish mill motor room. However, this was only achieved with the aid of an army of people sweeping up throughout the day.

Note 4. The enormous expense of dust control equipment, now mandated by the Alkali Inspectorate, was always emphasised in plant descriptions of the time, with cement companies' resentment barely disguised. However, the main source of dust nuisance by far was the intermittent process of moving weathered "outside stock" clinker - never remediated in any way during the life of the plant. However, in comparison with the knee-deep drifts of dust on most plants, Shoreham was always relatively clean.

Note 5. The road was finally widened 30 years later, not long before the bridge was demolished.

Note 6. This fineness standard was antiquated even at the time; British Standards had adopted specific surface as the measure of fineness in 1947.

Note 7. The use of this number - which is obviously a capacity rather than an output - is curious. Two kilns making 23 tons per hour for 95% of a year produce 383,000 tons a year of clinker, or 403,000 tons of cement. The plant regularly exceeded this. Furthermore, the plant was a few years later extended by the recommissioning of the old kiln, adding another 80,000 tons a year.

Note 8. This rather thin slurry was necessary to enable pumping down the.rather convoluted 4.43 km pipeline. It limited the plant's kiln feed moisture to about 42.5%, as shown in the approximate mass balance to make slurry containing 100 tons of dry raw material (DRM):

DRM less flintwaterflinttotal% H2O
Clay21.25.30.026.520.0
Water Added44.2
Clay Slurry21.249.50.070.770.0
Chalk78.817.25.0101.017.0
Water added7.2
Kiln Feed100.073.90.0173.942.5

An inevitable small water addition at the main plant resulted from chute lubrication, flint washing and pump glands.

Note 9. The old clay pit was the one immediately to the west of the washmills, that opened up in 1900 when the plant first started using local clay, and continued in use until 1950.

Note 10. Most of the chalk extracted at Shoreham was from the Lewes Nodular Chalk Formation, whcih contains numerous relatively hard bands. The new quarry commenced in the thin cap of softer Seaford Chalk. Later, blasting was used fairly consistently.

Shoreham Quarry Geology

The map shows the original extent of the Seaford Chalk Formation with a dotted line.

Note 11. To my knowledge, the crusher was never lowered.

Note 12. This is the standard mixer specified by APCM for many years. They held 1309 m3 when filled to 1' from the top (to avoid splashing on the rim track). For clay, this was equivalent to 1608 tonnes of slurry, or 482 tonnes of dry clay, which would make 1403 tonnes clinker (about 30 hours kiln run). It was therefore necessary to run the clay plant 7 days a week when the plant was in full operation. Changes in material dug in the clay pit very quickly manifested themselves in the finished slurry. In the 1980s, clay was brought to the plant by road and processed on site. The use of contract quarrying at the clay field allowed clay to be extracted from blended stockpiles, ironing out the large variations in clay chemistry that characterised the original system.

Note 13. The term "sand" refers to the particle size rather than the composition. Hard chalk paricles escaped the grinding process: the small flint typically contained 10-20% chalk, the secondary mill "beach" around 30-40%, and the screener "sand" 60-70%.

Note 14. Slurry composition was measured by acid/alkali carbonate.determination. This had a precision of about ±0.10% CaCO3 (1s) if done carefully, and the blending system could reduce the real variability of the slurry to below that, if properly metered. However the dosing process was rather hit-and-miss. In the 1980s, the system was entirely automated, removing human error from the process. Wet chemical testing was also replaced with XRF analysis in the 1980s.

Note 15. The depth was calculated by measuring the pressure developed by the slurry column, using a mercury manometer. Mercury regularly got "lost" in the slurry and was continually topped up at great expense. In any case, the technique depended on a constant slurry density (and therefore constant moisture content). The system was replaced with radar sensors in the 1980s.

Note 16. Actrually 10' 0¼"; the external.diameter was 10' 2", with plate of ⅞" thickness. Vickers Armstrongs supplied a large number of kilns of this design: Tolteca (Mexico) kilns 2 & 3 and Lichtenburg (South Africa) kilns 1 & 2 lit up in 1949: the two at Shoreham and Bamberton (Canada) kilns 4 & 5 lit up in 1951: Portland (Australia) kiln 1B (1952): Tolteca kilns 4 & 5 (1954) and Lichtenburg kiln 3 (1955). Hope kiln 5 (1953) was a modified form with satellite coolers. There may have been others, supplied outside Blue Circle.

Note 17. This guess was about 50°F too high.

Note 18. 23% standard coal was equivalent to an energy consumption of 6.47 MJ/kg. In the first 20 years, the average was actually 7.4 MJ/kg.

Note 19. From around 1958, site joints were also welded, but before that date the technology was not available in the UK.

Note 20. This is the "design" expansion - 0.256%. The actual expansion varied greatly with the state of the brickwork and coating.

Note 21. Until well into the 1950s, the Alkali Inspectorate considered that "a good chain system" was adequate dust suppression technology for small kilns. Chains were installed solely as heat exchangers: the suggestion that chains "caught" the dust was solely for Alkali Inspectorate consumption. Chains generated most of the dust.

Note 22. Actually 9’0¾” ID. These coolers accompanied most of the 350' kilns, and were also installed on Kent kilns 1 & 2, to replace the original FLS coolers.The various accounts, and the contemporary plans all say that the length (including the 2'6" outlet grid) was 90'0". However, these (and those at Kent) were subsequently lengthened by 2', perhaps to improve oversize discharge.

Note 23. This temperature (=110°C) was not achieved. Over the first two decades, the average clinker temperature was 387°F (197°C). The identical coolers on Kent kilns 1 & 2 averaged 162°C, but these kilns had output only 64% of that of Shoreham.

Note 24. This still reads like a description of a novelty. In fact, eight previous new kiln installations had been provided with precipitators from the outset - four pre-war and four post-war.

Note 25. Like so much of the data here, this is more a statement of intent than of actuality. 0.4 grains per cubic foot = 915 mg/m3. This was the maximum level for new installations mandated by the Alkali Inspectorate since 1945.

Note 26. This did not last long. The method used consisted of mixing the dust with water in a small ball mill and pumping the resulting slurry to the storage tanks. Interestingly, that "dust should only be returned to kilns in the form of a slurry" was another of the Alkali Inspectorate's mandates at the time. Because of high levels of salts in the dust, this caused the slurry to gel and thicken. From then on, dust was dumped, either in the chalk quarry, or the clay field. The latter dump sterilised a considerable amount of useful clay, and had to be removed in the 1980s to access the available clay reserve.

Note 27. This dust suppression feature appears to have been designed by someone unfamiliar with cement plants. The flimsy steel chutes were rapidly worn through by cascading clinker, and when no longer air-tight, could not gather the dust, which billowed up in an opaque cloud whenever clinker was being put to store.

Note 28. Also fed from the store to the mill clinker hoppers was raw chalk at a rate of 4-5% on clinker. This practice only ceased in the 1970s - throughout the first 15 years it was religiously observed. It had the effect of increasing the reported kiln outputs by 4-5%, while reducing the reported relative fuel consumption accordingly. It should not be imagined that Shoreham was unique in this.

Note 29. The sizing of the mills was designed to meet summer demand. All four mills could consume 80-85 tph of clinker, while the kilns (including No.3) could produce 55-60 tph. It also allowed winter demand to be met by only night-time working, using cheap power.

Note 30. Note that the lining is not mentioned. The mill was briefly recommissioned in a busy summer period in the 1980s, and had the distinction of still possessing its original silex (shaped flint) lining.

Note 31. This was almost (Plymstock had an elevator and belt) the last finish mill system to be installed with drag conveyors and belts. After this, pumps were always used to convey cement. The inclined belts at Shoreham rose 75' in 260' horizontally - an angle of 16°. The cement continually trickled, and occasionally cascaded, off the lower tail end - a defect that was never satisfactorily remedied.

Note 32. .

Note 33. .