Patent ID: 8506263
Filing Date: 2013-08-13
Classification: F04B,F04C

Abstract:
1. A vacuum pump comprising: a pumping mechanism; a drive shaft for driving the pumping mechanism; a gear box connected to the drive shaft for rotating the drive shaft; and pressure control means defining a path to allow fluid to flow from a swept volume of the pumping mechanism into the gear box and vice versa to reduce the pressure difference therebetween, wherein a part of the path is defined by a first conduit extending between the pumping mechanism and the gear box and being separate from and other than a fluid passage along the drive shaft, and, located in said path, a reservoir for collecting oil passing via the fluid passage along the drive shaft from the gear box towards the pumping mechanism so that, in use, pressurised fluid flowing from the pumping mechanism towards the gear box urges oil collected in the reservoir towards the gear box via a second conduit separate from and other than the fluid passage along the drive shaft.