| 摘要 |
PCT No. PCT/GB92/00531 Sec. 371 Date Oct. 28, 1993 Sec. 102(e) Date Oct. 28, 1993 PCT Filed Mar. 23, 1992 PCT Pub. No. WO92/16749 PCT Pub. Date Oct. 1, 1992.A reciprocating vacuum pump has a disc shaped piston (22, 122) having a peripheral elastomeric seal (52, 152) with oppositely directed, radially outwardly extending skirt portions (54,56); the piston is driven axially by a rod (34, 134) reciprocal in a lubricated bearing (42, 142) and a lubrication flowpath (50,48; 150,148) is defined between the bearing (42, 142) and the side of the piston (22, 122) opposite thereto.
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