GB540026A - Improvements in and relating to reducing valves - Google Patents

Abstract

540,026. Pressure-regulating valves. GRAHAM, J., GRAHAM, D. A., and AULD & SONS, Ltd., D. April 22, 1940, Nos. 7252/40 and 4913/41. [Class 135] A pressure regulating valve of the kind controlled by a relay valve has the relay valve arranged to control the admission of high pressure fluid to the underside of a main actuating diaphragm or the like, the upper face of the diaphragm being subject to either low pressure or high pressure. In the form shown in the Fig. 1 high pressure fluid from the inlet 2 acts on the underside of the main valve 8 and passes through a port 5 to a chamber 4 where it acts on the upper face of a diaphragm. This diaphragm is clamped centrally between members 12, 13 on the valve spindle 9 and peripherally between a flange on the lower part of the main casing and a detachable dome-shaped cover 17. The relay valve 24 is actuated by a spring-loaded diaphragm 29 and controls the passage of high pressure fluid from the chamber 4 through passages 19, 19a, 39, 20a, 20, 21 to a chamber 171 in the cover 17 beneath the diaphragm. Fluid escapes from this chamber through passages 21, 20, 20a, 36, 38 and pipe 40 to the low pressure side of the main valve under the control of an adjustable throttle 37. In a modification high pressure acts on the upper side of the main valve and is admitted directly to the chamber above the relay valve. In this form the upper side of the main diaphragm is subject to low pressure.