GB1364854A - Vacuum pump - Google Patents

Abstract

1364854 Rotary vacuum pumps CENCO Inc 23 Aug 1971 39375/71 Heading F1F In a two stage sliding vane vacuum pump in which a pair of rotors 23, 33 are mounted on a shaft 26 to rotate in stators 22, 32 on each side of a centre wall 14 and between end walls 40, 42, lubrication of the second stage and of a centre bearing 27 is achieved by oil drawn from a reservoir in which the pump is immersed flowing around a securing bolt 41 to a recess 70 in the stator 32 and from there into a series of grooves 72, 73, 74, Fig. 4, formed in the centre plate, the groove 73 which is substantially tangential to the shaft 26 being located to be swept by the rotor and vanes 37, 38 and dimensioned to produce a controlled flow of oil. Excess oil from the region of the centre bearing 27 flows along a keyway between the shaft 26 and rotor 33 to a recess 80 in the end wall 40 from where it is led, via a groove (81) Fig. 5 (not shown) to a low-pressure region of the second stage pump. Oil is drawn from the reservoir via a plate 63, Fig. 8 comprising a sheet of material folded and cut to the shape shown and secured to the end wall 40 by the bolt 41 to reduce the possibility of impurities in the oil being drawn into the pump. The oil in groove 72 effects sealing between the inlet and outlet sides of the second stage. Ballast air may be admitted to the second stage via a spring-biased ball valve, Fig. 2 (not shown).