Cement Kilns

Chinnor

Location:

  • Grid reference: SP7544700085
  • x=475447
  • y=200085
  • 51°41'40"N; 0°54'30"W
  • Civil Parish: Chinnor, Oxfordshire

Clinker manufacture operational: 1921 - January 1999

Approximate total clinker production: 10.7 million tonnes (39th)

Raw materials:

  • Middle Chalk (Holywell Nodular Chalk Formation: 92-94 Ma) and Grey Chalk (Zig-zag Chalk Formation: 94-97 Ma) from 475800,199800
  • Chalk Marl (West Melbury Marly Chalk Formation: 97-100 Ma) from 475500,199900

Ownership:

  • 1919-1963: Chinnor Cement and Lime Ltd
  • 1963-1979: Chinnor Industries
  • 1979-1/1999: Rugby Group

Hydraulic lime was made here from 1908, using five beehive kilns and an open kiln, and cement production began in 1921 using four chamber kilns (127 t/week): a further block of three (95 t/week) was added shortly afterwards.

Various sources say 1919, but production began in 1921: RC15/5/2, p 2. Some sources call the kilns “flare kilns” or “tunnel kilns”, but reliable contemporary sources and photographs show that they were Batchelor kilns.

The lime kilns were replaced with six shaft kilns (240 t/week) in 1938 and lime production continued until 1974. The chamber kilns continued in use intermittently after the first rotary kiln was installed, and were last used in 1931. Kiln A1 was modified by addition of what was claimed to be the first calcinator in 1934, and continued as such until it was replaced with B1. The other kilns were all Vickers desiccators, with minimal additional heat exchange. Until the 1960s, the plant was an independent company, and increased capacity gradually, with small units. The lack of sufficient raw material to justify a major re-build led to its closure during the late-1990s downturn.

The plant used the Watlington branch of the GWR for transportation: this remained open solely for plant freight after 1961, and closed in 1989, after which only road transport was used. The site has been demolished, the No 3 stack being finally felled in January 2008. One of the bottle kilns (No 3) has been restored. The quarries are un-restored and partially flooded.

Please contact me with any relevant information or corrections. I am particularly interested in firmer dates and statistics.

Rawmills

  • The original rotary kiln installation had a 75 kW washmill with three Allen rotary separators returning oversize to the washmill. The whole system was run from a common 93 kW drive.
  • These were replaced on installation of kiln 2 in 1937 with a Vickers 168 kW washmill and a 150 kW tube mill for re-grinding separated material.
  • With installation of kiln 3, a second similar parallel set of equipment was added, complete with crushers and feeders. The regrind mills were operated in closed circuit using Dorr Oliver sieve bends.

Four rotary kilns were installed:

Kiln A1

Supplier:Edgar Allen
Operated: 9/1928-1961
Process: Wet: with calcinator from 1934
Location: Hot end (cooler ports) 475471,200101: Cold end 475441,200061
Dimensions (from cooler outlet port): 164’8”× 9’0”B / 7’6”CD (metric 50.19 × 2.743 / 2.286): the overall length was 185’0”.
Rotation (viewed from firing end): anticlockwise
Slope: 1/24 (2.388°)
Speed: 1.2 rpm
Drive: 30 kW
Kiln profile: -6350×2286: 2210×2286: 3835×2743: 12421×2743: 14046×2286: 50038×2286: tyres at 5156, 1194, 15062, 30150, 45237: turning gear at 27711
Cooler: none – extended nose section with lifters, and from 1934 parallel cooler tubes 6 × 3.962 × 0.800
Fuel: Coal
Coal mill: initially indirect: 149 kW Edgar Allen "combination" mill. From 1954, direct: No16 Atritor
Exhaust: initially via dry drop-out chamber and ID fan to stack. In 1934 the calcinator was built on top of the drop-out chamber, and the calcinator exhaust passed through cyclones followed by the ID fan.
Typical Output: 1928-1933 125 t/d : 1934-1942 165 t/d: 1947-1961 151 t/d
Typical Heat Consumption: 1928-1933 7.6 MJ/kg: 1934-1942 6.5 MJ/kg 1947-1961 7.0 MJ/kg


Kiln A2

Supplier: Vickers Armstrong
Operated: 7/1937 -1/1999
Process: Wet
Location: Hot end (cooler ports) 475469,200111: Cold end 475432,200063
Dimensions (from cooler ports): 201’4½”× 9’0”BC / 12’6”D (metric 61.38 × 2.743 / 3.810)
Rotation (viewed from firing end): anticlockwise
Slope: ?
Speed: ?
Drive: 45 kW
Kiln profile (from cooler ports): -495×2134: 1029×2134: 3162×2743: 49949×2743: 53607×3810: 60312×3810: 60922×2019: 61379×2019: tyres at 6972, 22212, 39281, 54674: turning gear at 36843.
Cooler: Reflex “Recuperator” planetary 10 × 15’6” × 3’6” (metric 4.72 × 1.067)
Fuel: Coal, replaced with up to 70% Petcoke in the 1990s.
Coal mill: Indirect: ball mill. From 1954, direct: No16 Atritor
Exhaust: Initially via eight parallel cyclones and ID fan to stack. In 1976 cyclones removed and electrostatic precipitator added after the ID fan.
Typical Output: 1937-1948 187 t/d: 1949-1956 199 t/d: 1957-1967 197 t/d: 1968-1980 191 t/d: 1981-1999 205 t/d
Typical Heat Consumption: 1937-1956 8.0 MJ/kg: 1957-1967 7.75 MJ/kg: 1968-1980 8.19 MJ/kg: 1981-1999 8.40 MJ/kg


Kiln A3

Supplier: Vickers Armstrong
Operated: 1/1958-1/1999
Process: Wet
Location: Hot end (cooler ports) 475459,200119: Cold end 475411,200056
Dimensions: (from cooler ports) 261’1”× 10’6”B / 9’3”C / 13’6”D (metric 79.58 × 3.200 / 2.819 / 4.115)
Rotation (viewed from firing end): clockwise
Slope: 1/24 (2.388°)
Speed: ?
Drive: 75 kW
Kiln profile (from cooler ports): -1194×2591: -584×3200: 25019×3200: 27153×2819: 67691×2819: 71349×4115: 78511×4115: 79121×2286: 79578×2286: tyres at 6731, 22276, 37821, 54280, 72873: turning gear at 41478.
Cooler: Reflex “Recuperator” planetary 12 × 15’0” × 4’0” (metric 4.57 × 1.219)
Fuel: Coal, replaced with up to 70% Petcoke in the 1990s.
Coal mill: Direct: No18 Atritor
Exhaust: Initially via eight parallel cyclones and ID fan to stack. In 1976 cyclones removed and electrostatic precipitator added after the ID fan.
Typical Output: 1958-1977 284 t/d: 1978-1999 307 t/d
Typical Heat Consumption: 1958-1977 6.97 MJ/kg: 1978-1999 7.32 MJ/kg


Kiln B1

Supplier: Vickers Armstrong
Operated: 9/1962-1/1999
Process: Wet
Location: Hot end 475475,200107: Cold end 475432,200049
Dimensions (from cooler ports): 238’0”× 10’0”B / 9’0”C / 13’6”D (metric 72.54 × 3.048 / 2.743 / 4.115)
Rotation (viewed from firing end): clockwise
Slope: ?
Speed: ?
Drive: 60 kW
Kiln profile (from cooler ports): ?
Cooler: Reflex “Recuperator” planetary 12 × 15’0” × 4’0” (metric 4.57 × 1.219)
Fuel: Coal, replaced with up to 70% Petcoke in the 1990s.
Coal mill: Direct: No18 Atritor
Exhaust: Initially via eight parallel cyclones and ID fan to stack. In 1976 cyclones removed and electrostatic precipitator added after the ID fan.
Typical Output: 1962-1979 246 t/d: 1980-1999 272 t/d
Typical Heat Consumption: 1962-1979 7.02 MJ/kg: 1980-1999 7.17 MJ/kg



Sources: Cook, pp 66, 101, 116: Jackson, pp 218, 276: The Chinnor Cement and Lime Company’s New Cement Factory, Edgar Allen pamphlet, 1928 (Rugby Archive RC15/5/2): “A 40,000 ton a Year Plant”, Cement and Cement Manufacture, 1, June 1928, pp 93-96: “New Oxfordshire Cement Factory”, Cement and Cement Manufacture, 2, June 1929, pp 97-107: “Investigations on a slurry drier or calcinator”, Cement and Cement Manufacture, 9, June 1936, pp 115-128; July 1936, pp 139-154; October 1936, pp 207-220


© Dylan Moore 2011: commenced 07/08/2011: last edit 31/12/2016.

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Old Maps

Detail plans of the plant have been partially completed, but further progress is prevented by lack of information on the layout of the later plant.

Approximate capacity: tonnes per year
Chinnor Capacity

Britain from Above features some of the oldest and most valuable images of the Aerofilms Collection, a unique and important archive of aerial photographs. You can download images, share memories, and add information. By the end of the project in 2014, 95,000 images taken between 1919 and 1953 will be available online.
This was taken on 3/8/1937 and shows the plant from the east. The remains of the chamber kilns, complete with stack, are visible to the left. Kiln 2 was in course of construction and was not working here. To the right of the taller (Kiln 2) stack, the building housing the calcinator on Kiln 1 is visible. At the rear of the site is the original set of lime kilns: at the left hand end of the row are the shaft lime kilns that superceded them. The plant at this stage was using only Lower Chalk. Higher grade chalk was later taken from the toe of the escarpment across the road. Zoom in on the view in High Definition.

Displayed by kind permission of John Frearson. This beautiful image, used on the home page of this website, is dated 1938, and shows the firing floor, looking south-west, at around the time kiln 2 (right) was being commissioned. There is a good view of the shield plate that seals the end of the Vickers "Recuperator" reflex planetary cooler. On kiln 1 to the left, one can see the ends of two of the five "cooling tubes", added as a desperate measure to the Edgar Allen integral cooler section. The hopper and drive wheel at the top is probably kiln 1's fine coal feeder.