GB680677A - Water supply system for forced recirculation steam generator - Google Patents

Abstract

680,677. Forced-flow steam boilers. COMBUSTION ENGINEERING-SUPERHEATER, Inc. Aug. 2, 1950 [Oct. 27, 1949], No. 19277/50. Class 123 (ii) In a forced-flow boiler supplying, for example, heating steam to a train and comprising a number of tubular coils 11, connected in parallel between supply and collecting headers 12, 13, a steam-and-water separating drum 15, a recirculating pump 18, and a feed pump 24, the discharge pipe 27 of the latter is connected to the pipe 19 between said header 13 and drum 15. The feedwater is thus heated before entry to the boiler proper and the liberated gases escape with the steam through the steam outlet 16 of the drum 15. The feed pump 24 is driven by steam from the drum 15 which is led to the pump cylinder 23 through a pipe 21, provided with a control valve 22 regulated by a float in the said drum, and exhausts through a pipe 35 to atmosphere, or to the feedwater tank 26 through a pipe 33, this pipe 33 being fitted with a regulating restriction 36, or a valve 37 regulated by a thermostat in the tank 26, and an eductor 34, the latter receiving, by a pipe 32, cooling water from the gland 30 of the pump 18 which is supplied by a branch 31 of the pipe 27. The recirculation pump 18 returns water from the separating drum 15 to the generating coils 11 through a pipe 20 which is fitted with a strainer 40 and a return pipe 47 to a mud chamber 48 provided at the bottom of said drum and fitted with a blowdown 51, and the pipe 47 has, in effect, an extension 52 returning to the pipe 27 between a check valve 53 in the latter and its connection to the pipe 19: The strainer 40 comprises a casing 41 housing a cylindrical screen 42 the interior of which communicates with the part 20A of the pipe 20, and the screen is fitted with an external member 44 to divide the flow therethrough between the part 20B of the pipe 20 and the return pipe 47.