| 摘要 |
<p>A vacuum pump is provided with at least one cylinder having a cylinder liner (22) and a piston (35) mounted for reciprocating movement within the cylinder liner. The piston is connected to a crankshaft (54) for reciprocating the piston and the piston is provided with a piston head having a flat surface. A valve plate (62) is biased into engagement with the end of the cylinder liner whereby during upward movement of the piston the flat face of the piston contacts the valve plate. The piston is provided with two annular lip seals.</p> |
