GB965415A - Improvements in or relating to apparatus for effecting the supply of feed water to steam generators and the like - Google Patents

Abstract

965,415. Feedwater supply systems for steam boilers. HICK HARGREAVES & CO. Ltd., and F. L. DONNISON. Oct. 31, 1961, [Aug. 30, 1960; Sept 2, 1960], Nos. 29832/60 and 30300/60. Heading F4A. In a feed water supply apparatus for steam generators a boiler feed water pump or like device is supplied from a water storage tank disposed between the said pump and one or more deaerating headers adapted to be supplied with steam and water and means are provided whereby a steam space within the storage tank is substantially isolated from pressure fluctuations within the headers. In the form shown, condensate is fed through a pipe 3 to a deaerating header 6 by an extraction pump 2 from a surface condenser 1. Bled steam is fed via the pipes 4, 5 to the deaerating header 6 and also to a baffled storage tank 8 via a non-return valve 13. An outlet pipe 7 from the header 6 leads to below the water level of the storage tank 8 and an outlet 9 from this tank leads through a lowpressure control valve 10 to an additional tank 11 and thence to a feed pump 12. Differential heads H 1 , H 2 vary with the rate of flow of water from the condenser, a decrease in flow causing a rise in pressure in the deaerator 6 and a reduction in the head H 1 ; correspondingly an increase in the flow causes a fall in pressure in the deaerator 6 with the resultant rise in the head H 1 . These variations in head accommodate variations in pressure in the deaerator and ensure that the vessel 8 is under constant pressure conditions. The head H 2 is controlled by the valve 10 so that the head of water above saturation pressure at the pump inlet is automatically varied so as to cause the discharge pressure to be adjusted to a value required by the system.