| 摘要 |
A pump 10 e.g. a screw pump, includes a main pumping element 12 and a generally parallel auxiliary pumping element 13, 14, and a pump housing 11, the main and auxiliary pumping elements 12, 13, 14 interacting with each other and with an internal wall 27, 28, 29 of an elongate pumping chamber 23 of the housing 11 as they relatively rotate to pump fluid from a first axial inlet end 32 of the elongate chamber 23 towards a second axial outlet end 33 of the elongate chamber 23, and wherein the internal wall 27, 28, 29 of the elongate pumping chamber 23 includes at least one recess 35 which extends along at least a substantial portion of the axial extent of the chamber 23 between the inlet and outlet ends 32, 33 of the chamber 23, an adjacent pumping element 12, 13, 14 being contactable with the chamber wall 27, 28, 29 at discrete contact edges 36 either side of the recess 35. <IMAGE> |
