GB632435A - Improvements relating to the regulation of the supply of feed water in a steam generator - Google Patents

Abstract

632,435. Feedwater supply systems for steam boilers. SULZER FRERES SOC. ANON. Nov. 4, 1946, No. 32662. Convention date, Nov. 23, 1945. [Class 123(ii)] [Also in Group XXIX] A forced-circulation steam boiler, comprising essentially a steam-and-water collecting vessel 11, a tubular evaporator 13 with circulating pump 13a, and a superheater 17, is supplied with feed water by passing a greater part, say 80-90 per cent, of the water, regulated primarily in dependence upon the rate of steam consumption, to the vessel 11 through a pipe 7, controlled by a valve 20, an evaporating pre-heater 9 and pipe 10, the lesser part of the water being fed direct to the vessel 11 through pipes 5, 12 with an interposed valve 47 which is subjected to the control of a float 43 in the said vessel. As shown, the valve 20 is regulated by a servomotor piston 21 controlled by a valve 28 which is influenced' not only by the steam flow in the outlet pipe 19 but, preferably, also by the water flow through the pipe 7 and the steam pressure or temperature within the vessel 11, through pipes 36, 36a, and 40 respectively. Further the lever 48 through which the valve 47 is actuated by the float 43 is associated with a second valve 49 located in the boiler blow-down or drain pipe 15, 15a in such a manner that when the valve 47 is closed by the float any further level rise in the vessel 11 will effect opening of said drain pipe,' and, preferably, the drain valve 49 is fitted with a byepass 53 including a hand valve 52. The invention is also described in connection with a boiler in which the evaporator 13 is dispensed with, the vessel 11 being heated by direct or indirect contact with steam from the superheater 17 or by the circulation of an external medium through a heating coil disposed therein. Reference has been directed by the Comptroller to Specification 603,588.