| 摘要 |
<p>This invention relates to a vacuumpump. The pump comprises a pump housing (10) having an upper and a lower cylindical, partly liquid filled, compression chamber (11 and 12 resp.) which are separated from each other and in which an upper and a lower part (14, 15) of a piston (12) is movable. The piston has a passage (21) which is provided with a check valve and which is a communication between the upper and the lower chamber (11 and 12 resp.). The upper chamber communicates via an opening (26) which is provided with a check valve with a liquid filled deaeration receptacle (27) whereas the lower chamber (12) during a part of the movement of the piston via an inlet (33) communicates with the space being evacuated. <IMAGE></p> |
