摘要 |
<p>The present invention relates to a scroll pump (10) which comprises two scrolls (20, 22) which are co-operable for pumping fluid from an inlet to an outlet on relative orbiting motion of the scrolls. Each scroll (20, 22) comprises a scroll base (30, 36) from which a scroll wall (28, 34) extends generally axially towards the base of the opposing scroll. A gas conduit (38) having an inlet (40) at a first location of the pumping channel (32) and an outlet (42) at a second location of the pumping channel allows over-compression at the first location of the pumping channel to be exhausted to the second location of the pumping channel. A one-way valve (44) located in the gas conduit (38) allows the passage of gas through the conduit from the conduit inlet (40) to the conduit outlet (42) only when a predetermined pressure differential between the first and second locations of the pumping channel is generated during roughing when the scroll inlet is at or close to atmosphere.</p> |