A vane pump is disclosed that includes a plurality of vanes and radial slots configured to provide a gap between the vane and the radial slot such that the vane has a different angular position relative to the direction of rotation in a radially extended position compared to an angular position in a radially-retracted position. The different angular positions provide different orientation of the arcuate surface of the vane tip portion with respect to the cam body inner surface, thus providing different fluid stop points on the vane tip portion arcuate surface.

A vane pump is disclosed that includes a plurality of vanes and radial slots configured to provide a gap between the vane and the radial slot such that the vane has a different angular position relative to the direction of rotation in a radially extended position compared to an angular position in a radially-retracted position. The different angular positions provide different orientation of the arcuate surface of the vane tip portion with respect to the cam body inner surface, thus providing different fluid stop points on the vane tip portion arcuate surface.

A vane pump is disclosed that includes a plurality of vanes and radial slots configured to provide a gap between the vane and the radial slot such that the vane has a different angular position relative to the direction of rotation in a radially extended position compared to an angular position in a radially-retracted position. The different angular positions provide different orientation of the arcuate surface of the vane tip portion with respect to the cam body inner surface, thus providing different fluid stop points on the vane tip portion arcuate surface.

A multi-stage vacuum pump may include first and second half-shell components defining a plurality of pumping chambers and for assembly together along respective longitudinal extending faces; first and second end stator components for assembly at respective longitudinal seals for sealing between the first and second half-shell stator components when assembled together at the longitudinally extending faces; and annular seals for sealing between the first and second end stator components and the first and second half-shell stator components when assembled; wherein the longitudinal seals have end portions which abut against the annular seals for sealing therebetween and the first and second half-shell stator components have formations for resisting movement of the end portions away from the annular seals when the end portions are compressed between the first and second half-shell stator components.