| 摘要 |
A scroll pump has two intermeshing scrolls arranged so that on relative orbital movement of the scrolls gas is pumped from an inlet 38 to an outlet 36. The scrolls have a plurality of successive scroll wraps I, II, III, IV, V, VI between the inlet and the outlet. There is a single-start condition in which fluid is pumped from the inlet to the outlet along a single flow path extending through each of the scroll wraps in succession and a multi-start condition in which fluid is pumped from the inlet along a plurality of flow paths which extend in parallel through radially adjacent scroll wraps and converge to a single flow path prior to the outlet. In another arrangement the pump has two different multi-start configurations. A valve arrangement 56 is operable for switching the scroll pump between the configurations. |
