| 摘要 |
908,212. Valves. OIL CENTER TOOL CO. Oct. 4, 1960 [Dec. 28, 1959], No. 33971/60. Class 135. A relief valve for controlling fluid comprises a housing 11 having inlet and outlet passages 34, 32, a valve closure member 62 urged by a spring 82 into contact with a seat 40, the closure member being moved out of contact with the seat by a piston 54, detent means 132, 134 for preventing the piston from moving the closure member, and detent release means 102, 106 responsive to inlet pressure and adapted to release the detent means from the piston when the inlet pressure rises above a predetermined level. As shown, the piston 54 forms an integral part of a slidable member 50 which is loaded by the spring 82 thereby normally maintaining the valve 62 in contact with the seat 40. A pilot piston member 100 is mounted within the member 50 and is loaded by a spring 110. The detents, which comprise rollers 132 connected by links 134, are mounted in the member 50 and, in the closed position of the valve shown, the rollers co-operate with an annular groove 24 in the housing wall and with the cylindrical end 102 above the piston 100. In operation, when an increase in pressure builds up in the inlet 34, the pressure acts on the piston 100 via passages 94, 96 in the member 50 which moves upwardly thereby releasing the detent from the groove 24 and thus allows the member 50 to lift against the action of the spring 82 and open the valve 62. When the member 50 reaches its limit of travel, a spring- loaded detent 152, 154 engages with a groove 140 formed on the member 50 and thereby retains the valve in the open position. |
