GB754347A - Improvements in and relating to air pumps - Google Patents

Abstract

754,347. Rotary pumps. ALFA-LAVAL CO., Ltd., and CLARK, T. L. March 8, 1955 [March 8, 1954], No. 6683/54. Class 110(2) A rotary vacuum pump having vanes 6 of carbon sliding in a rotor 1 rotatable in a stator comprising a cylinder 3 and end plates 4 is provided with bearing members. of carbon between the end surfaces of the rotor and the ends of the stator chamber. The rotor shaft 2 extends through the plates 4 and is mounted in ball bearings 5, the rotor being provided at each end with an annular recess housing a rubber ring 7 and a carbon thrust ring 8. The rubber rings 7 are in compression so that the carbon rings 8 are forced into engagement with the end plates 4. In addition, the rings 7 act as a seal against air leakage. These rings 7 may be replaced by metal bellows. Recesses in the plates 4 house the bearings 5, the bearings being held by cover plates 10 against metal thrust rings 12 and compressed felt washers 11 prevent the entrance of grease from the bearings into the pump. Each cover plate 10 has a groove 13 to hold grease for the bearing, and a passage 14 in each plate 4 allows escape of excess grease. The driven end of the shaft 2 is surrounded by a felt washer 15 sealing the bearing on its outer side. In a modification, the carbon rings 8 are replaced by fixed carbon discs held between annular shoulders on the cylinder 3 and the end plates 4 of the stator. Rubber rings compressed between the discs and the plates 4 form a vacuum seal. The pump discharges through a silencer 23 as in Specification 754,333 and its inlet is connected to a pipe line 22 through a T-junction 21, one arm of which is a sump collecting condensed moisture. By removing a plug 20, the sump can be drained and a strainer sleeve 19 be taken out for cleaning purposes. Specification 669,012 also is referred to.