| 摘要 |
A reciprocating pump comprising a cylinder and a plunger reciprocable in the cylinder, a member at one end of the cylinder having an axial passage in which the plunger is axially slidable, and a seal between the member and the plunger. The pump is characterized in having a sleeve for protecting the seal from the effects of relatively high pressure and pressure fluctuations of fluid in the cylinder. The sleeve surrounds the plunger and is fixed in position inwardly of the member and has an axial bore in line with the axial passage in the member. The sleeve blocks communication from within the cylinder to the axial passage in the member except for such communication as there may be through the bore in the sleeve to the axial passage in the member. The plunger is axially slidable in the bore. The sleeve has internal grooving establishing a pressure reducing path for fluid from the inner to the outer end of the sleeve for reducing the pressure and fluctuations in pressure of fluid from the cylinder on the seal.
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