| 摘要 |
<p>1465123 Reciprocating pumps WANNER ENG Inc 4 Oct 1974 [5 Oct 1973] 43121/74 Heading F1A An hydraulically-actuated diaphragm pump comprises a diaphragm 44 separating a pumping chamber 50, with inlet and outlet valves 51, 52, from an actuating chamber 25, a piston 10 being reciprocable in chamber 25 and acting through a liquid column on diaphragm 44, entry of make-up liquid into the column from reservoir 39 being controlled by a check-valve 35 and a slide valve constituted by ports 38 and 29 in telescoping sleeves 26, 30 attached to piston 10 and diaphragm 44, respectively, so that entry of make-up liquid only takes place when the actuating chamber pressure is less than the reservoir pressure and the piston and diaphragm have moved towards one another sufficiently for port 38 to communicate with port 29. A spring 31 biases diaphragm 44 towards piston 10 to prevent cavitation in chamber 25. Piston 10 is reciprocated by a swash-plate 21. In Fig. 2 (not shown), the checkvalve is provided in passage 40.</p> |
