GB770954A - Improvements in or relating to boiler feed regulator valve mechanisms - Google Patents

Abstract

770,954. Fluid-pressure servomotor control systems. VICKERS-ARMSTRONGS (ENGINEERS), Ltd. March 10, 1955 [April 2, 1954], No. 9706/54. Class 135. A feed water-regulator valve for steam boilers is connected at 5 to the feed water pump and at 3 to the boiler and encloses a slidable valve member consisting of a closure element 7 coacting with a seat 4a and a piston 8 above which is a pressure chamber 2a in which a variable control pressure dependent upon the liquid level in the boiler and set up by the operation of a gear motor 11 and gear pump 12 is effective on the piston 8. The gear motor 11 is fed from the inlet to the regulator through a pipe 15, an adjustable valve 14, and conduit 13 and it discharges through a passage 17 leading to the outlet 3. The pump 12, which is directly driven by the motor 11, has an inlet 18 connected to the boiler at the liquid working level and a restricted outlet 19 to the outlet space 9 of the motor. The arrangement is such that when the liquid level in the boiler is below the working level steam is pumped by the pump 12 resulting in a comparatively low pressure drop across the motor 11 with consequent low pressure above the piston 8 allowing the valve to be opened by inlet pressure. When the water level in the boiler is above the working level and the pump 12 is pumping water, putting a greater load on the motor 11, the pressure drop across the motor is greater resulting in sufficient pressure in the chamber 2a to close the regulator.