Cliffe

Location:

Clinker manufacture operational: 7/1914-25/1/1970

Approximate clinker production: 10.5 million tonnes (39th)

Raw materials:

Ownership:

The plant was sometimes known as Thames Works, as was that of Gibbs and Co [see Thames (W Thurrock)]. Alpha called it Thames Works, but confusingly also referred to it as Rochester Works. In common with all the other Alpha plants, after 1934 it was called Alpha Works by the locals. The company was launched by builders’ merchants Broad and Co., as with British Standard, to escape the dictatorship of the Blue Circle monopoly. Although undoubtedly a very shaky operation, it escaped takeover by Red Triangle, but was bought by Alpha, who, as at other plants, installed calcinators which were subsequently removed by Blue Circle. There was for most of the plant's history no rail link, and the plant relied largely on river transport. The plant was originally connected to a wharf on Higham Creek at Cliffe Fort, initially by a 1.59 km ropeway used to send out cement and bring in coal. In 1935 this was replaced by a 2 ft gauge tramway leading to a new deep water wharf adjacent to Cliffe Fort. A substantial part of the plant's output was shipped to Scotland. A short branch rail line was extended to the plant in 1961, with six bulk loading silos, and trains to Uddingston, near Glasgow, began.

Because of the vast reserves of alluvium in the Cliffe marshes, it supplied many of the other Thames plants with this, using water transport. Clay was dug using a floating pontoon carrying a dredge crane and washmill, from which the clay slurry was pumped to a holding tank on the Thames shore. From there, the slurry was carried up river by two purpose-built 500-ton tanker ships - the Claycarrier (launched 6/1937), and the Claytransporter (launched 5/1939). Reception tanks were built on the shore at Bevans, Swanscombe, Johnsons and Kent. Cliffe clay suffered the disadvantage of relatively high salinity, which caused problems for kiln electrostatic precipitators. Following closure, the site was largely cleared, and is now occupied by a Brett Aggregates materials processing facility.

Power Supply

The plant was entirely electrically driven from the outset, using power produced by turbo-generators. From 1936, purchased power from the grid was used.

Washmills

Clay was washmilled at the clay field and the slip was pumped to the plant where it was washmilled with chalk in a coarse and a fine washmill.

Four rotary kilns were installed:

Kiln A1

Supplier: Ernest Newell
Operated: 7/1914-1936
Process: Wet
Location: hot end 572076,175641: cold end 572118,175685: hot end enclosed.
Dimensions: 202’0”× 10’0”B / 8’6”CD (metric 61.57 × 3.048 / 2.591)
Rotation (viewed from firing end): ?
Slope: ?°
Speed: ?
Drive: ?
Kiln profile: 0×2591: 1981×2591: 3429×3048: 15621×3048: 17069×2591: 61570×2591: Tyres at 1372, 17678, 36576, 54102
Cooler: rotary 80’6”× 6’4” (metric 24.54 × 1.930) beneath kiln
Cooler profile: 0×2078: 775×2078: 6039×1930: 24536×1930: Tyres at 3810, 18745
Fuel: Coal
Coal Mill: indirect: Griffin mills serving kilns 1 & 2
Exhaust: direct to stack. A waste-heat boiler was added in the 1920s.
Typical Output: 1914-1920 144 t/d: 1920-1936 163 t/d
Typical Heat Consumption: 1914-1920 8.28 MJ/kg: 1920-1936 8.14 MJ/kg


Kiln A2(=B2)

Supplier: Ernest Newell
Operated: 1924-03/01/1970
Process: Wet: a calcinator was added in 1936 and removed in 1957
Location: hot end 572070,175647: cold end 572113,175690: hot end enclosed.
Dimensions: 200’0”× 9’10”B / 9’0”CD (metric 60.96 × 2.997 / 2.743)
Rotation (viewed from firing end): ?
Slope: ?°
Speed: ?
Drive: ?
Kiln profile: 0×2661: 3226×2661: 5004×2997: 14910×2997: 16129×2743: 60960×2743: Tyres at 2134, 17221, 35204, 53797.
Cooler: rotary 68’0”× 7’5”/ 6’4” (metric 21.16×2.261/1.930) beneath kiln
Cooler profile: 0×1803: 1219×2261: 5182×2261: 6248×1930: 20726×1930: Tyres at 3854, 14675.
Fuel: Coal, except 1961-1968 Oil
Coal Mill: indirect: initially Griffin mills: from 1936, Tirax ball mill, later operated direct.
Exhaust: direct to stack, via a waste-heat boiler. This was removed and a fan and cyclones were added with the calcinator in 1936. Two APCM "Unit" electrostatic precipitators were added after the fan in the 1960s.
Typical Output: 1924-1930 188 t/d: 1930-1936 241 t/d: 1936-1957 232 t/d: 1957-1961 254 t/d: 1961-1968 246 t/d: 1968-1970 222 t/d
Typical Heat Consumption: 1924-1930 8.11 MJ/kg: 1930-1936 7.82 MJ/kg: 1936-1957 7.09 MJ/kg: 1957-1961 8.05 MJ/kg: 1961-1970 8.50 MJ/kg


Kiln B1

Supplier: FLS
Operated: 1938-1969
Process: Wet: originally with calcinator, removed in 1957
Location: hot end 572076,175641: cold end 572118,175685: hot end enclosed.
Dimensions, metric:

Rotation (viewed from firing end): ?
Slope: 1/25 (2.292°)
Speed: ?
Drive: ?
Kiln profile:

Cooler: FLS bucket grate
Fuel: Coal, except 1961-1968 Oil
Coal Mill: indirect: Tirax ball mill, later operated direct.
Exhaust: the calcinator was followed by fan and cyclones. Two APCM "Unit" electrostatic precipitators were added after the fan in the 1960s.
Typical Output: 1938-1957 359 t/d: 1957-1961 318 t/d: 1961-1968 321 t/d: 1968-1969 268 t/d
Typical Heat Consumption: 1938-1957 7.41 MJ/kg: 1957-1961 8.36 MJ/kg: 1961-1968 8.85 MJ/kg: 1968-1969 8.75 MJ/kg


Kiln B3

Supplier: FLS
Operated: 1936-25/01/1970
Process: Wet
Location: hot end 572063,175652: cold end 572133,175724: hot end enclosed.
Dimensions:

Rotation (viewed from firing end): ?
Slope: 1/25 (2.292°)
Speed: ?
Drive: ?
Kiln profile:

Cooler: 1936-9/1953 Unax planetary 11 × 6.30 × 1.200: 9/1953-1970 Fuller 733S grate: 10° slope.
Fuel: Coal, except 1961-1968 Oil
Coal Mill: originally indirect: Tirax ball mill. Replaced in the 1950s with 2 direct firing Atritors.
Exhaust: originally ID fan followed by a Lodge Cotterell electrostatic precipitator. This was replaced with two APCM "Unit" precipitators in the 1960s.
Typical Output: 1936-1953 382 t/d: 1953-1961 407 t/d: 1961-1968 387 t/d: 1968-1970 360 t/d
Typical Heat Consumption: 1936-1953 6.88 MJ/kg: 1953-1961 6.93 MJ/kg: 1961-1968 7.23 MJ/kg: 1968-1970 7.58 MJ/kg



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