GB362547A - Improvements in or relating to steam power plants - Google Patents

Abstract

362,547. Feedwater supply systems for steam boilers. ROE, R. C., 167, Rockwood Place, Englewood, New Jersey, U.S.A. Sept. 19, 1930, No. 28079. Convention date, Oct. 12, 1929. [Classes 64 (i) and 123 (ii).] Feedwater is heated in stages by direct contact with steam bled from a number of points in a turbine of variable load. The steam power plant comprises a high-pressure steam generator 10, direct contact feedwater heaters 28 .. 32, bleed conduits 33 .. 37 connecting the heaters with points of different pressure in the turbine 12, centrifugal pumps 40, 43, 46, 52, 57 for pumping the feedwater successively through the heaters in the order of increasing pressure, and electric motors 48, 69 for driving the pumps. The flow and pressure characteristics of the pump and turbine are coordinated for different loads. The operations of the pumps and turbine, and of the load and feedwater heating are interrelated. The condensate from condenser flows to a hot-well 38 from which it passes by pipe 39 to pump 40. From here it passes to heater 28 by pipe 41, condenses steam therein, and passes by pipe to the next pump, and so on through the various heaters. The pumps 40, 43, 46 are on one shaft. Tanks 49, 61 and control apparatus are associated with heaters 30, 32. The connections between the pumps and heaters are arranged to provide sufficient head to effect an automatic adjustment between the various pump elements so that one regulator controls the combined units. The levels in the tanks 49, 61 depend upon the amount of steam used in the turbine. Float chambers are associated with the tanks. The floats affect pilot controllers. 68, 71 having electric contacts which control reversible, constantspeed motors 75, 77 to operate rheostats 76, 78 to vary the speed of the pump motors 69, 48. A float regulator may be placed in the hot-well 38. The pump units may be arranged on a single shaft and driven by a single motor. A float in a chamber 55 may be arranged beneath the heater to control a valve 74 in the discharge pipe. Valves opened or closed by oil pressure against the resistance of springs are arranged in the bleed-steam lines, and are closed when the emergency gear operates. Check valves 90 prevent accidental back-now of water through the bleed mains.