GB1205698A - Pressure regulating valves - Google Patents

Abstract

1,205,698. Valves. PARKER-HANNIFIN CORP. 8 Nov., 1968, No. 53084/68. Heading F2V. A pressure reducing valve comprises a valve member 29 controlling flow between inlet and outlet passages 11, 12, and responsive to pressure derived from the outlet acting on the diaphragm 47 in a control chamber 57 against a loading spring 53. In order to avoid vibration or hunting, a resultant control pressure is derived by combining two different pressures which enter a pressure combining chamber with a phase difference through separate passage means from the inlet. Pressure is led firstly through relatively unrestricted passage means comprising grooves 24, and an annular chamber 26 round a seat member 34, and secondly from the interior of the seat member through a restricted passage 44, a slit in an insert tube 38, and a slight clearance between a land 23 on the seat member and a bore 15, into the chamber 26 which constitutes the pressure combining chamber. The tube 38 may be used also as a pressure gauge connection, by removing a plug 42. Overpressure at the outlet is vented from the control chamber through a seat 49 carried by the diaphragm. In order to avoid "regulator droop" or drop in pressure between the normal maximum pressure in outlet port 12 and the pressure therein at which flow through the valve is reinstated, a bleed groove (64), Fig. 5 (not shown), is formed in the relief seat 49. This bleed groove may be replaced by a bleed hole to atmosphere directly from the outlet passage 12.