Read The Engineer at Grace's Guide.
The following is a transcript of an anonymous article that appeared in The Engineer, 116, 15 August 1913, p 167. It is believed to be out of copyright. It describes the Sundon plant after the installation of the second rotary kiln, which was the largest kiln in Britain at the time of its installation.
Values of imperial units (as of 1918) used in the text (alphabetical order): 1 acre = 0.40468424 Ha: 1 ft = 0.30479947 m: 1 gallon = 4.5460756 dm3: 1 HP (horse-power) = 0.7456998 kW: 1 inch = 25.399956 mm: 1 psi (pound-force per square inch) = 6.89478 kPa: 1 ton = 1.01604684 tonne: 1 yard = 0.91439841 m.
Sundon Cement Works, Harlington, near Dunstable
The works of this firm, which is associated with the British Portland Cement Manufacturers, Limited, are situated at Harlington. about 15 miles from Bedford and 5 miles from Luton.
The works were first constructed with 14 Johnson chamber kilns, but in 1901 Schneider kilns were erected, the flues of the chamber kilns being roofed in and covered with cast iron plates to provide a floor to dry materials for the Schneider kilns. In 1902 (Note 1) an American rotary kiln, 60 ft. by 6 ft., was installed by F. L. Smidth and Co., of Copenhagen, and in 1908 (Note 2) an order was placed with Edgar Allen and Co., of Sheffield, for a rotary kiln 150 ft. long by 7 ft. 6 in. diameter.
The manufacture of cement at these works is carried on progressively in the following order:
From the chalk quarry the materials consisting of chalk and marl (mixed in the necessary proportions determined by chemical analysis) are conveyed to the wash mill by an endless chain hauling gear (Note 3). Here they are fed through rolls into the mills, where they are washed through gratings and elevated to the wet mill. This contains three sets of Clarke's mills, through which the slurry passes into the mixers by gravity. From the mixers it is distributed to the rotary kiln slurry storage tanks by Taylor's three-throw pumps, and then it is pumped direct into the kiln through reducing nozzles. The No.2 kiln, installed by Edgar Allen and Co., Sheffield, is 150 ft. long by 7 ft. 6 in. diameter, with an enlarged burning zone 8 ft. 6 in. diameter (Note 4). The heat given up by the clinker as it passes through the cooler is used to dry the coal (Note 5). The clinker is delivered on to a shaker conveyor and then elevated and conveyed direct to the grinding plant or storage ground. In the grinding plant the clinker, after passing through steel roller crushers, is elevated to storage bins, where it passes by gravity to the Kominor Mills. Here it is prepared for the tube mills, which do the final grinding. It is then elevated and conveyed to a cement warehouse, which consists of a series of bins each of 1000 tons capacity (Note 6). The power plant consists of two twin-cylinder and one single-cylinder gas engines by the National Gas Engine Company, developing 800 brake horsepower. There are seven suction gas plants. There is a well-equipped laboratory and testing-room, where the materials are tested at various stages of manufacture. The number of men employed at these works is about 150.