| 摘要 |
<p>The piston pump assembly has an inlet valve (6a) which, in the closed setting, is closer to the working zone (4) than when in the open position. The valve surfaces towards the working zone (4) at the entry (6a) and/or outlet (6b) valves move into the inner surface of the working zone (4) when they are closed, without a shoulder.</p> |
