All About Engines

T74 All About Engines twenty-five years ago. This in itself constitutes a record. The whole plant includes a high-pressure and low-pressure “ rotor ” or drum on the same shaft, coupled to a huge electric generator with a small one used as an “ exciter ” at the extreme end. The total length is 76 feet 2 inches, the greatest width is 18 feet, and the depth from base to top is 10 feet. Just below the low-pressure casing is an enormous sur- face condenser reaching 20 feet below the floor level. The shaft is nowhere less than 16 inches in diameter, and is in three lengths of not less than 20 feet. The low-pressure casing alone weighs 150 tons. When working at full power it will require 281,250 lb., or 125J tons, of steam, and about 5,600,000 lb., or 2,500 tons, of condensing water per hour! Steam is generated at 200 lb. per square inch and superheated by 2000 Fahr., making the tem- perature about 6000 Fahr. It enters the steel casing at the high-pressure end, and passes through sixty- four rows of blades in six sets. These blades vary in length from 2| to 6J inches. Thence it passes to the low-pressure turbine, which is of the double- flow pattern, the steam entering at the centre and flowing towards the ends. The pressure is here 25 lb. per square inch absolute, or 10 lb. per square inch above that of the atmosphere. In each half there are twenty-four rows of blades, or forty-eight rows in all, varying in length from 2f to 19 inches. Having done its work, the steam flows to the condenser through a rectangular orifice, 21 feet long and 12