RELIEF AND UNLOADING VALVES

摘要

1349676 Valves GREER HYDRAULICS Inc 19 April 1971 [17 Feb 1970] 22382/71 Heading F2V A pressure relief valve has a closure member 46 biased on to seat 48 by gas pressure within bladder 13 whose end wall is moulded around the head 42 of the closure member. The opposite end of the bladder is anchored by plate 23 incorporating a gas admission valve. The closure member responds at 47 to system pressure and controls flow from system line 35 to exhaust at 36. The space around the bladder is vented via passage 20 and porous fitting 201. In the modification of Fig. 3, when the pressure of fluid flowing from inlet 99 to outlet 101 exceeds the loading pressure within bladder 77, the latter uncovers exhaust port 74 to which the fluid flows via perforated support screen 75. In a further modification (Fig. 2, not shown) an unloading valve similar to Fig. 1 has a closure member which is responsive at its free end (60) to accumulator pressure and has a reduced intermediate section (52) controlling communication between a pump outlet (371) and an exhaust port (361).