| 摘要 |
<p>A double acting liquid pump has a main piston reciprocating in a casing which has entry and delivery holes in its base for a hydraulic piston in the base connected to the main piston, and has a pneumatic slide valve housed in the top. This slide valve moves between two positions so that in one position drive fluid is fed to the main piston so that it is directed to a small aea face of the piston, and so that in the further position of the main valve, the slide valve is switched to the second position and the fluid is directed to a large area face of the main piston.</p> |
