Fig. 71. Mirlees-Diesels at Dundalk.
(66) Willans-Diesel Engines.
The Willans-Diesel engines built by the Willans and Robinson Company of Rugby, England, are in sizes up to 400 brake horsepower, and run at speeds up to 250 revolutions per minute. They are all of the four stroke cycle type and are applied principally to the driving of electric generators. The cut shows one of the four, 280 horse-power units supplied to the Alranza Company and the Rosario Nitrate Works in South America.
Fig. 72. Willans Vertical Diesel Engine.
Unlike the Mirlees engine, the Willans has an individual frame for each cylinder as in steam engine practice. Like the steam engine frame, the bottom is left open for the inspection of the connecting rod ends and the main bearings which is a most desirable feature. The air compressor and pumps are arranged in a most compact form at the left end of the crank-shaft from which the pipes may be seen issuing to the four cylinders. The valves and over head gear are of the conventional type, which, with the exception of a few minor details are the same as those on the recently developed Sulzer-Diesel. The individual grouping of the cylinder units has many desirable features and should, we believe, be more extensively copied.
(67) Installation and Consumption of Diesel Plant.
An English gas-electric station was completed at Egham, England, that is a good example of the changes that have been made recently in the electricity supply abroad, with Diesel power.
The generating plant comprises two 94 K. W. Diesel engines built by Mirrlees, Bickerton and Day, direct connected to single phase alternators generating at 2,000 volts. The exciters are direct connected to the main shaft, and the plant is capable of generating an overload of 10 per cent for two hours. Space has been left for the installation of two more units of a larger size.
The following fuel consumption was guaranteed for a load of unity power factor, and the official tests show slightly better figures than the guarantee.