Multiple-shaft vacuum pump with gears divided off from pumping space

摘要

Seals within the shaft ducts are each composed of two lips (16,17), one lip to face towards the pumping space (1) whilst the second lip is directed towards the drive or bearing space (9). Thus the lips of those facing the pumping space reach into recesses (20) designed into the pump pistons (2) and the pistons are bevelled (21) over their inside diameter where they face the sealing lip so as to allow condensate or other fluids to drain away from the sealing area. A line (18) brings in block gas between the two seals only to flow over via bushing (19) in both directions towards the two spaces. The blocking gas stands at higher pressure than the pressure in the pumping or bearing spaces. The gas flows continuously over to the spaces as a function of pressure or volume, typically assuming a two shaft vacuum pump, using the drive space for the pump rotation to the pistons via bearing plate doubling up as divider between pumping and bearing spaces.