Abstract: The present disclosure relates to a rotary vane vacuum pump 300 (300?) comprising a gas ballast assembly 330. The gas ballast assembly 330 comprises a gas ballast passage fluidly connected to a stator chamber 212 of the pump 300, a gas ballast valve 334 configured to selectively open and close the gas ballast passage depending on the relative gas pressure across the valve 334, and a gas ballast buffer chamber 360 fluidly connected to the gas ballast passage upstream of the gas ballast valve 343, which is in selective fluid communication with the exterior of the pump 300 (300?). The present disclosure also provides a related method of communicating ballast gas to a rotary vane vacuum pump 300 (300?).

Abstract: The present disclosure relates to a two-stage rotary vane vacuum pump casing 200 that comprises an exterior surface 202 and a first plurality of cooling fins 204 (214) protruding from the exterior surface 202, wherein each cooling fin 204 (214) extends along the exterior surface 202 between a first and second cooling fin end 201a, 201b, and is a non-planar element that forms an at least partially enclosed cooling channel 206 (216) between the first and second ends 201a, 201b of the cooling fin 204 (214b). The present disclosure also provides a method of making a two-stage rotary vane vacuum pump casing 200 using extrusion and providing a removable end plate for a two-stage rotary vane vacuum pump casing 200.