Cement Kilns

Barnstone

Barnstone cement logo

Barnstone Cement Co. Ltd logo. See what they're doing there? The village was actually called Barnston, but the name was officially changed in the 1920s to agree with the rebus. This logo appeared on jute bags: the colour scheme of the "official" logo is unknown. If you know the correct colours, please contact me.

Location:

  • Grid reference: SK73713505
  • x=473710
  • y=335050
  • 52°54'28"N; 0°54'14"W
  • Civil Parish: Langar cum Barnstone, Nottinghamshire

Clinker manufacture operational: 1886 to 1969

Approximate total clinker production: 3.7 million tonnes

Raw materials:

  • Blue Lias Limestone and shale (Blue Lias Formation, Barnstone Member: 197-200 Ma) from quarries at 474000,335000 and 473150,334650
  • After hand-picking of limestone ceased (early 1920s?), sweetener Inferior Oolite (Lower Lincolnshire Limestone Member: 168-172 Ma) from:
    • Waltham on the Wolds, Leicestershire 481300,325200 (13 km)
    • Sproxton, Leicestershire 486300,325100 (17 km)
    • Stroxton, Kesteven 488900,330600 (16 km)
  • After Portland cement manufacture ceased, only off-site materials were used.

Ownership:

  • 1875-1878 T & R Marshall
  • 1878-1896 Barnstone Blue Lias Lime Co.
  • 1896-1914 Barnstone Blue Lias Lime and Cement Co. Ltd
  • 1914-1942 Barnstone Cement Co. Ltd
  • 1942-2001 APCM (Blue Circle)
  • 2001-2006 Lafarge

Initially the plant made Blue Lias lime with sixteen bottle kilns. The first attempt to make Portland cement was in 1885, when a Ransome rotary kiln was installed. As with the others, it was ineffective, failing to reach clinkering temperature. An attempt to increase the temperature by recycling hot air from the cooler pit blocked the firing pipe and destroyed the gas producer. Actual manufacture began in 1886, using eight of the bottle kilns (output 125 t/week) in dry process mode. A Schneider kiln was installed in 1899 (output 60 t/week). Another pair of Schneider kilns was added before 1906. Davis (1907) rated the three at 200 t/week . An 18-chamber Hoffman ring was installed around 1908. It was decommissioned (although it remained in place) when rotary kiln A2 was installed. The Schneider kilns remained in intermittent use until 1937, and remained in place until the 1970s. The plant was reconstructed on a new site in 1927, and kiln A2 was subsequently (1937) moved to the new site and lengthened as B2. The plant was served from the outset by a 0.7 km spur from the Nottingham-Melton Mowbray branch railway. The plant ceased Portland production in 1969, but remained in use (with B2 only) until May 2006 as an experimental plant and to make non-Portland special clinkers and cements – predominantly sulfoaluminates.

Rawmills

For the rotary kiln plant there were two 224 kW 6'× 32’6” (1.829× 9.906) Edgar Allen "combination" mills.

Four distinct rotary kilns were installed:

Kiln A1

Supplier: Ransome
Operated: installed 1885 – never produced commercially
Process: “Long” Dry
Location: ? : entirely enclosed
Dimensions: 21’0”× 3’6” (metric 6.40 × 1.067)
Rotation (viewed from firing end): ?
Slope: 1/17 (3.372°)
Speed: ?
Drive: worm drive from steam engine: power draw not known but probably around 150 W
Kiln profile: 0×1067: 6401×1067
Cooler: none
Fuel: Producer gas
Typical Output: 3 t/d (calculated - did not produce)
Typical Heat Consumption: 13.2 MJ/kg (calculated)


Kiln A2

Supplier: Edgar Allen
Operated: 1914-1936 (then moved and extended as B2)
Process: Wet
Location: Hot end 473645,335164: Cold end 473615,335140 : entirely enclosed
Dimensions: 125’0”× 7’0” (metric 38.10 × 2.134)
Rotation (viewed from firing end): ?
Slope: ?
Speed: ?
Drive: ?
Kiln profile: 0×2134: 38100×2134: Tyres at 3353, 16916, 31090
Cooler: rotary (Dimensions? not the same cooler used on B2) beneath kiln
Cooler profile: ?
Fuel: Coal
Coal mill: ?
Typical Output: 77 t/d
Typical Heat Consumption: 8.5 MJ/kg


Kiln B1

Supplier: Edgar Allen
Operated: 1927-1969: removed 1972
Process: Wet: initially fitted with slurry sprays
Location: Hot end,: Cold end, : entirely enclosed
Dimensions: 150’0”× 8’6”B / 7’6”CD (metric 45.72 × 2.591 / 2.286)
Rotation (viewed from firing end): ?
Slope: ?
Speed: ?
Drive: ?
Kiln profile: 0×2286: 3061×2286: 4699×2591: 12052×2591: 13697×2286: 45720×2286: Tyres at 2134, 14630, 28804, 42977
Cooler: rotary 55’0”× 5’0” (metric 16.76 × 1.524) beneath kiln
Cooler profile: 0×1524: 16764×1524: Tyres at 4267, 12370
Fuel: Coal
Coal mill: Initially semi-indirect with turbo pulveriser. Later, direct: No16 Atritor
Typical Output: 1927-1937 108 t/d: 1937-1953 132 t/d: 1953-1960 149 t/d: 1960-1969 160 t/d
Typical Heat Consumption: 1927-1937 8.08 MJ/kg: 1937-1953 7.39 MJ/kg: 1953-1960 7.65 MJ/kg: 1960-1969 6.87 MJ/kg


Kiln B2

Supplier: Edgar Allen, modified: was A2 extended by 25’ and re-sited
Operated: 1937-1969: non-Portland clinker production 1969-2006.
Process: Wet
Location: Hot end,: Cold end, : entirely enclosed
Dimensions:

  • 1937-1954?: 150’0”× 7’0”BC / 11'0"D (metric 45.72 × 2.134 / 3.353)
  • 1954?-2006: 150’0”× 7’0” (metric 45.72 × 2.134)

Rotation (viewed from firing end): ?
Slope: ?
Speed: ?
Drive: ?
Kiln profile:

  • 1937-1954?: 0×2134: 37795×2134: 39014×3353: 42062×3353: 42367×2134: 45720×2134: Tyres at 3353, 16916, 31090, 43891
  • 1954?-2006: 0×2134: 45720×2134: Tyres at 3353, 16916, 31090, 43891

Cooler: rotary 55’6”× 4’6” (metric 16.92 × 1.372) beneath kiln
Cooler profile: 0×1372: 406×1372: 1143×1676: 7468×1676: 8230×1372: 16916×1372: Tyres at 1543, 12649
Fuel: Coal
Coal mill: Initially semi-indirect with turbo pulveriser. Later, direct: No16 Atritor
Typical Output: 1937-1949 115 t/d: 1949-1955 124 t/d: 1955-1963 131 t/d: 1963-1969 126 t/d
Typical Heat Consumption: 1937-1955 7.45 MJ/kg: 1955-1963 7.48 MJ/kg: 1963-1969 6.72 MJ/kg



Sources: Francis, pp 219-220, 233-234: Jackson, pp 210, 270: Pugh, p 262: Circle 8 (1981) pp 10-11: “Electrical Equipment at the Barnstone Cement Works”, Cement and Cement Manufacture, 2, July 1929, pp 197-201 (Read this). The local website contains some pictures.



Old Maps

A detail plan of the plant has been partially completed, but further progress is prevented by lack of information on the layout of the earlier plant.

Approximate capacity: tonnes per year
Barnstone clinker capacity

This section is still under construction.

The Barnstone cement plant was described in an anonymous article in Cement and Cement Manufacture (II, July 1929, pp 197-201), shortly after it had been substantially re-built. Although the article was primarily concerned with electrical equipment, the process plant was described in reasonable detail. The text is believed to be out of copyright.

Although the Barnstone Cement Co. Ltd. was the 12th largest of 29 firms operating in Britain in 1929, it represented only 1% of national capacity. The investment described represents an attempt to keep up with advancing technology at a time of cut-throat competition. The new equipment was essentially a very modest-sized new plant on a new site. The old kiln was later re-sited alongside the new one.

Electrical Equipment at the Barnstone Cement Works

The Barnstone Portland Cement Works has been established for many years at Barnstone (Note 1), Nottinghamshire. Recently the Company has installed an entirely new plant with up-to-date machinery and modern labour-saving devices, which is electrically operated throughout. The contract for the supply and erection of the new machinery was carried out by Messrs. Edgar Allen & Co., Ltd., whilst the electrical equipment, including switchboards, motors and motor control gear, was manufactured and supplied by the General Electric Co., Ltd. Some indication of the extent of the electrical equipment may be gathered from the fact that the total normal capacity of the motors is approximately 2,000 h.p., ranging in individual outputs from 5 h.p. to 450 h.p.

The use of electricity for driving cement works machinery offers many important advantages over older types of driving units employed. The fact that the electric motor is so suitable for individual drive permits of the machines used at the various stages of manufacture being grouped to better advantage than if their relative positions were determined by the driving machinery; moreover, the electric motor can often be accommodated in small spaces which otherwise would be wasted. Ease of control is another very important feature of electric driving, while by installing ammeters as part of the control unit the power taken by any machine can readily be ascertained. Frequently the knowledge that a machine is taking more power for driving than it should will enable faults to be detected in an initial stage which otherwise might lead to much more serious trouble, perhaps involving the shutting down of plant for some days.

Electric power is taken from the 11,000-volt mains of the Derbyshire and Nottinghamshire Electric Power Co. It is transformed down in the Power Company's sub-station at the works and fed at 440 volts to a G.E.C. truck cubicle switchboard, consisting of three units. Two of these control the low tension side of transformers, each being equipped with type 4 G.E.C. oil-circuit breakers of maximum breaking capacity of 100,000 kVA, fitted with overload protection, together with isolating links, measuring instruments, instrument transformers, etc. The third truck is an outgoing metering cubicle equipped with maximum-demand watt hour meter, voltmeters, and the necessary instrument transformers. The outgoing cables from this cubicle are led to the truck-cubicle feeder board shown in Fig. 2, which distributes power to the motors driving the machinery via ironclad distribution boards, control pillars, etc., as required. The principal equipment of each of the trucks comprises an oil circuit-breaker of suitable breaking capacity fitted with overload protection, watt hour meter, ammeter, and necessary accessories.

The G.E.C. truck-cubicle board occupies a minimum of floor space; the apparatus is readily accessible for inspection as it is mounted on a truck which can be easily withdrawn from the cubicle providing the oil circuit breaker is open, and due to this provision safety to the operator is ensured, as the truck cannot be withdrawn while the breaker is closed. In addition, the withdrawal of the truck causes a shutter to fall, completely covering the holes through which the movable contact plugs pass in order to engage with the fixed contacts on the busbars. It will thus be seen that live metal is never exposed.

The cement produced in these works is manufactured on the wet process, burning in a rotary kiln. The raw materials mainly consist of blue lias limestone, which is quarried on the site, with the admixture of a certain quality of stone containing a high percentage of calcium carbonate (Note 2). These raw materials are delivered in full-gauge trucks to a large jaw crusher, which reduces it in one operation to about 3 in. and under. The stone is mechanically fed to the crusher by means of a finger feeder, consisting mainly of heavy grid bars with spaces between them and arranged at a slight slope to the horizontal. Some of these bars have a rocking movement backwards and forwards given to them by a driving shaft carrying eccentrics, and by this means the stones move forward towards the crusher jaws. This crusher and feeder is belt-driven by a 125-h.p. "Witton" motor running at 580 revolutions per minute.

The crushed stone falls on to a slightly inclined troughed band conveyor and is fed into a rotary screen, the rejects from the screen passing on to a set of medium-speed crushing rolls, 30 in. in diameter by 20 in. wide, where they are reduced to about 2-in. cube and under. The stone is then elevated by a continuous-bucket elevator and deposited on to a steel-band conveyor over two large reinforced concrete storage silos containing the two qualities of raw stone. These silos are hoppered at the bottom and rotary-table feeders are fitted at the outlets, by which means the raw stone is measured in the proportions required to give the correct chemical composition.

A band conveyor takes the raw stone to the grinding mill, which is a "Stag" combination ball and tube mill, 6 ft. diameter by 32 ft. 6 in. long, grinding wet, water being fed in with the stone. The mill is of sufficient capacity to prepare the ground slurry for the plant. It is driven by a 300-h.p. "Witton" motor running at 244 r.p.m., direct coupled to the mill countershaft. The motor is housed separately from the mill. The power for supplying this motor is controlled by a G.E.C. draw-out oil-immersed ironclad pillar; the draw-out features embodied in this pillar are similar to those of the truck-type cubicle already described. The motor is operated by a G.E.C. type IV liquid controller.

The slurry as it comes from the mill is elevated by a slurry wheel (Note 3), 28 ft. diameter, carrying buckets on its periphery, and runs by gravity to two triple mixers. The finished slurry runs by gravity into a large storage mixer of the "sun and planet" type, from whence it is pumped by means of three-throw plunger pumps direct to the kiln, which is belt driven by a 30-h.p. "Witton" variable speed motor with a range of 357-715 r.p.m. The coal for the kiln is delivered from trucks direct into a feed hopper, and elevated to a large storage hopper over the pulverisers.

Two turbo pulverisers are installed (Note 4), each driven by an 80-h.p. "Witton" motor, running at 1,450 r.p.m., which is direct coupled to the pulveriser shaft, and carried on the same bedplates as the machine. One pulveriser is of sufficient capacity to provide powdered coal for firing the kiln, the other machine being used as a standby. The coal is pulverised, air separated, and blown into the kiln in one operation, and coal up to 10 per cent. moisture content is used.

The kiln is fitted with the Rigby-Allen patented slurry atomising equipment at the feed end (Note 5), and an induced-draught fan is provided for dealing with the waste gases. The hot clinker as it comes from the kiln passes through a rotary cooler, 5 ft. diameter by 55 ft. long, and is handled from the cooler end by means of an Allen "swing tray" conveyor, which either delivers the clinker to the storage silos or direct to the cement grinding mill.

The cement mill consists of a "Stag" combination tube mill, 6 ft. 6 in. diameter by 36 ft. long, driven by a 450-h.p. three-phase "Witton" motor running at 244 r.p.m., direct coupled in a similar manner to the raw mill. This motor with its liquid starter is shown in Fig. 4, the control being similar to that of the 350-h.p. raw mill motor.

A small plant is provided for crushing and feeding gypsum, and automatic table-feeders are used for regulating the feed of clinker and gypsum to the mill in the right proportion. The ground cement is elevated and conveyed to three large reinforced concrete silos, whence it is extracted and packed mechanically into bags for despatch.

Reference has been made to the control of the 300-h.p. and 450-h.p. tube-mill motors. The other motors are controlled by suitable pillars, or panels, consisting in general of an oil circuit-breaker with starter. In the case of motors from 30 h.p. to 125 h.p. the starter is of the oil-immersed rotor pattern, whilst for the smaller motors auto-transformer starters are employed. The main power wiring consists of paper-insulated lead-covered cables, single-wire armoured, except between rotor starters and rotors where the cable is in flexible tubing.

The extensions described in this article were carried out under the direction of Mr. J. Ward, Managing Director of the Barnstone Cement Co., Ltd., to whom we are indebted for permission to publish the information and photographs.

- o - O - o -

NOTES

Note 1. The name of the township is correctly Barnston, although it was called Barnstone through the nineteenth century. The name was corrected in 1888, and the cement company successfully petitioned to get it changed back in 1905.

Note 2. The Barnstone Lias is two-thirds shale, and the limestone layers overall are rather marginal in carbonate. At this stage, the plant used selected (rumbled) limestone from the Lias, and needed an addition of about 5% sweetener stone, which was Inferior Oolite from Waltham on the Wolds, 13 km away. Later, when the whole of the lias was used, imported stone usage rose to 60%.

Note 3. So Allen were still installing this ancient technology as late as 1928.

Note 4. These are Clarke-Chapman turbo pulverisers, for which Allen had exclusive rights in the cement industry. They were later replaced by Atritors.

Note 5. The Harbury article describes these in detail. They were soon removed and replaced with chain systems.

Original content © Dylan Moore 2011: commenced 10/08/2011: last edit 16/06/2017.

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