Centrifugal pumps are well adapted to service in either large or small units. An installation in a manhole at Park Point, Duluth, is shown in Fig. 61. This station is controlled by an automatic electric device which is operated by a float in the suction pit. Such automatic control is an added advantage of the use of electrically driven centrifugal pumps. The Calumet Pumping Station in Chicago, shown in Fig. 49, has a capacity of approximately 1,000 cubic feet per second. The simplicity of the layout of this station is shown in Fig. 62.
Fig. 62.—Interior Arrangement of the Calumet Sewage Pumping Station, Chicago.
Eng. News-Record, Vol. 85, 1920, p. 872.
80. Steam Pumps and Pumping Engines.—The direct-acting steam pump, one type of which is shown in Fig. 63, is adapted to pumping sewage the character of which will not corrode or clog the valves. In this form of pump it is necessary to utilize the steam at full pressure throughout the entire length of the stroke, which results in high steam consumption. A flywheel permits the use of steam expansively during a part of the stroke, thus increasing the economy of operation. Other devices used for the same purpose are known as compensators. They are not in general use.
Steam engines are classified in many different ways, for example; according to the type of valve gear, as, plain slide valve, Corliss, Lentz, etc.; or according to the number of steam expansions, as, simple, compound, triple-expansion, etc.; or according to the efficiency of the machine as low duty or high duty; or as
Fig. 63.—Section of Duplex Piston Steam Pump.
Courtesy, The John H. McGowan Co.
STEAM END
2 Steam cylinder and housing combined. 8 Steam piston head. 9 Steam piston follower. 10 Steam piston inside ring. 11 Steam piston outside ring (2). 12 Steam cylinder head. 14 Steam chest. 16 Steam chest cover. 17 Steam slide valve. 18 Steam valve rod. 20 Steam valve rod, pin and nut. 22 Steam valve rod, collar and set screw. 23 Steam valve rod, stuffing box. 24 Steam valve rod, stuffing box, nut and gland. 38 Piston rod. 47 Piston rod stuffing box. 48 Piston rod, stuffing box, nut and gland. 49 Valve gear stand. 51 Long valve crank and shaft. 52 Short valve crank and shaft.
PUMP END