| 摘要 |
A reciprocating pump for dispensing liquids from a container comprises a hollow body in which is slidably fitted a hollow piston. A piston seat is located in the body and provides a segment sized for sealing fit inside the hollow piston, thereby minimizing possible leakage through the pump when it is transported with a liquid filled container. Upper and lower valves are provided in the piston and body respectively. The piston seat is adapted to interact with the upper valve member to hold it open during a portion of an upward stroke of the piston thereby drawing any undispensed liquid back into the pump.
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