| 摘要 |
1,242,851. Reciprocating pumps. FLETCHER SUTCLIFFE WILD Ltd. Aug.15, 1968 [Aug.24, 1967], No.39104/67. Heading F1A. In a hydraulic pump whose pistons 2 are reciprocated by rotating eccentrics on a shaft 5 in a casing 6, lubricant at a predetermined pressure is supplied to the casing by a pump (27) Fig. 3, (not shown) and a drain groove 24 in each cylinder 1 communicates with an inlet manifold 12A to suck therein the leakage pumped fluid. The cylinders 1 may be arranged in groups, each having one such manifold 12A connecting the inlets of all the cylinders in that group, and each cylinder has separate inlet and outlet valves 13, 16 respectively. The output of any one cylinder may be made substantially zero by a control device comprising a piston 31 and tappet 21 which, when supplied with pressure through a control port 20, holds the inlet valve 13 open throughout the pumping stroke. A pressure relief valve (19) Fig.3 (not shown) connects the outlets of all the cylinders, combined in a manifold 4A, to the source of pumped fluid and a relief valve is provided for relieving excess pressure of lubricant in the casing 6, from which leakage to the cylinders is limited by a sealing ring 26 provided at the junction of each cylinder with the casing. |
