GB699797A - Improvements in or relating to closed feed systems for steam power plants - Google Patents

Abstract

699,797. Feedwater supply systems for steam boilers. WEIR, Ltd., G. & J., and HILLIER, H. May 11, 1950, No. 11757/50. Class 123 (ii) A closed feedwater supply system for a steam power plant including a boiler and turbine, not shown, comprises, in series, a steam condenser 1, a condensate extraction pump 3 discharging through pipes 4, 17 to a deaerator 16, and a de-aerator extraction pump 28 discharging through a pipe 14 to the boiler feed pump 11. Both the pumps 3, 28 have recirculation connection 6, 7, 9 and 31 respectively to the condenser 1 and de-earator 16, the flows through the pipes 9, 31 being regulated by valves 8, 32 which are controlled by floats 10, 33 in the condenser well 2 and de-aerator tank 25 and are opened and closed at predetermined low and high water levels in said well and tank. The pipe 17 is also provided with a valve 18 controlled by a float 19 in the de-aerator tank 25, so that the flow from the condenser pump to the de-aerator is reduced when the level in the said tank rises, and vice versa; if desired, the valves 18 and the valve 32 may be operated by a common float. The system is completed by an elevated feed tank 5, which is in free connection by the pipe 6 with the condenser pump discharge pipe 4, and by a by-pass pipe 13 with non-return valve 12 between said pipe 4 and the supply pipe 14 of the feed pump 11. The capacities of the pumps 3, 28 are greater than that of the pump 11 so that in normal operation there is a recirculation of water through both the condenser and the de-aerator, and, should either of these pumps fail, then the pump 11 may draw water from the tank 5. Two or more such systems may be operated in parallel, the discharges 4A, 14A respectively from the condenser and de-aerator pumps in a second system being shown. A modified system with a low feed tank is also described.