All About Engines

Steam Turbines 175 feet wide, large enough for a crowd of men or a motor- car to pass through with ease. This condenser has a surface of 39,300 square feet, and is built of steel plates, with all the stiffen- ing girders on the outside in order to avoid inter- rupting the free flow of steam. The tubes are 1 inch in external diameter. This is rather larger than is usual, but there is less danger of them becoming choked by deposit than with smaller tubes. They are arranged in two “ nests,” one in the upper part and one in the lower part of the casing. The circulating water enters the lower compartment through a rectangular opening, 5 feet 9 inches by 2 feet 2 inches, and after passing through both compartments flows out through a tube 4 feet in diameter. Exhaust, Reducing, and Back-pressure Turbines So much for high-pressure turbines. An addi- tional merit of this form of prime mover lies in the fact that it is very efficient with a low pressure of steam. There are no narrow ports as in the ordinary reciprocating engine, except at the point where steam is admitted, and the steam passes through open- ings of gradually increasing size on its way to the condenser. The power that is obtained by increasing the vacuum in the condenser from 28 inches to 29 inches is greater than that obtained between 27 inches and 28 inches. Consequently, with a good air pump