GB138951A - Improvements in boiler feed water supply & steam condensing plants - Google Patents

Abstract

138,951. Fothergill, H., and Gunn, J. Sept. 26, 1918. Feed-water, supplying and controlling. - Relates to the de-aeration of feed-water. Vapour is withdrawn from the main condenser 1 by the steam-jet ejector 2 and delivered to the condensing-receiver 3, which is under vacuum. Another steam-ejector 5 withdraws from the receiver 3 and discharges into a surface feed-heater 6, from which the air escapes to atmosphere by the pipe 7. The condensate from the main condenser 1 is delivered by the pump 8 direct to the feedheater 6, and thence to the boiler-feed system by the pipe 9. Any additional steam required for heating the feed-water is admitted to the valve 6<a>. The hot drainage from the heater 6 passes by the pipe 11 to the tank 10, to which make-up water may also be supplied by the pipe 12. The water thus heated passes by the float-controlled valve 16 to the de-aeration chamber 4, into which it is sprayed by the sprayer 14. The water is deaerated under the action of the vacuum and then passes by the pipe 17 to mix with the air-free water from the main condenser 1. The de-aerating chamber may be separately constructed and connected to the chamber 3 by a pipe. To ensure a sufficient supply of water to the pump 8, a pipe 18 may be connected from the feed-pipe 9 to the condenser 1, through a valve 19 such as that described in Specification 135,885, [Class 32, Distilling &c.]. In a modification, the de-aerating chamber may be placed on the discharge side of the heater 6 and may be placed under vacuum by connecting it to the suction side of the ejector 5. The whole of the feed-water is passed through the de-aerating chamber. In another modification, Fig. 3, showing a marine condensing-plant, vapour is drawn from the main condenser 1 by the steam ejector 2 and delivered to the condensing-receiver 3. The vapour and condensate are withdrawn separately by a reciprocating pump 29, 30. The condensate passes to a tank 31. The de-aerating cahmber 30 is placed under vacuum by connecting it to a part of the vacuum system other than the main condenser, e.g. the discharge side of the ejector 2 or the auxiliary vacuum condenser 34. Feedwater is. sprayed into the chamber 20 from the tank 31 under the control of a float valve 35, so that a constant head is maintained on the suction side of the feed-pump 36, which discharges to the boilers through a surface heater 38. The drainage water passes from the heater to the tank 31 by a pipe 39. In another modification, the condensate from the main condenser passes through a small auxiliary surface condenser in which the steam from the ejectors is condensed direct to the feed-pump. The drainage water and condensate from the auxiliary condenser only are passed through the de-aerating chamber.