GB657170A - Improvements in or relating to closed feed systems for boilers - Google Patents

Abstract

657,170. Feedwater supply systems for steam boilers. WEIR, Ltd., G. & J., and HILLIER, H. Feb. 2, 1949, No. 2805. '[Class 123(ii)] [Also in Group XXIX] In a closed feed system for a boiler 12, Fig. 1, comprising a condenser 2 associated with, for example, a turbine 1, a condenser extraction pump 6, and a boiler feed pump 9, the pump 6 being provided with a direct discharge to the pump 9 through an air ejector condenser 7 and feed heater 8, said discharge 'has a return connection 21 to the condenser fitted with an automatic pressure-controlled valve 22 and restriction 23 which former functions to close the said return connection and prevent flow of water therethrough when the boiler requires such water and the pressure between the two pumps falls below a predetermined minimum. As shown, the connection 21 discharges into a steam passage 4 extending from the top of the condenser to the well, 3 thereof. A second connection 16, leading to make-up and overflow valves 14, 15 (see Group XXIX), controlled by a float 13 in the well 3, is also provided, a rise of level in the well causing the valve 15 to open to permit flow of water from the connection 16 through pipes 17, 19 to an external feed tank 18 and a fall of level opening the valve 14 to permit flow from the tank 18 and through a pipe 20 to the condenser. In a modification, a de-aerator, heated by steam bled from the turbine, is fitted in the connection 21. Fig. 5 shows an arrangement with such a de-aerator 37 which may be used when the condenser is out of action, when water can be drawn from the feed tank 18 by a pump 38 and sprayed into said deaerator through a pipe 39 and float valve 40. From the de-aerator the water is discharged by a pump 43 either through a pipe 44 into the suction line'of the pump 9 or into the condenser through a pipe 47 and control valve 48.