摘要 |
A plunger pump includes a pump housing and a plunger extending into a pumping chamber of the pump housing. A sleeve valve is mounted only on the plunger for reciprocation therewith and also for displacement longitudinally of the plunger and subdivides the pumping chamber, when in its closed position, into a suction space without, and pressure space within, the sleeve valve. An inlet communicates with the suction space, and an outlet with the pressure space, the latter having a one-way valve therein which opens during the pumping stroke of the plunger. A flexible diaphragm ring extends across a spacing between the pump housing and the sleeve valve and is sealingly connected to these components. The diaphragm ring is flexible and urges the sleeve valve toward its closed position. A liquid seal may be accommodated in a compartment separated from the suction space by the diaphragm ring.
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