GB1138095A

GB1138095A - Centrifugal and face contact seal

Info

Publication number: GB1138095A
Application number: GB2724467A
Authority: GB
Original assignee: Worthington Corp
Current assignee: Worthington Corp
Priority date: 1966-07-27
Filing date: 1967-06-13
Publication date: 1968-12-27
Also published as: DE1650248A1

Abstract

1,138,095. Shaft seals. WORTHINGTON CORP. 13 June, 1967 [27 July, 1966], No. 27244/67. Heading F2B. Sealing means for the shaft 2 of a centrifugal pump comprises an axially movable stator 26 which, when the shaft is stationary or rotating slowly, is urged by a spring 33 into sealing contact with a rotor 45 on the shaft and, when the shaft speed exceeds a predetermined amount, is moved out of contact with the rotor by the fluid pressure differential across the stator, leakage of fluid pressure along the shaft then being opposed by pressure created by impeller blades 47 on the rotor 45. The stator carries a sealing ring 43 and is slidably sealed by 0-rings 27, 28 in a recess 25 in a stationary element 104 which divides a seal chamber 105 into an inner chamber 106 and an outer chamber 107. Axial passages 35 in the stator connect the inner chamber 106 with a chamber 34 formed between the stator and the bottom of the recess 25. Further rotors 60 and 80 separated by a fixed member 70 are housed in the outer chamber 107, the rotor 60 having segmented blades 66 co-operating with ribs 73 on the member 70 and the rotor 80 having blades 83. Cooled and filtered fluid is supplied from a source (100, Fig. 1) to the chamber 107 via a conduit 96 and passage 95. The rotors 45, 60 and 80 are keyed to the shaft 2 by a key 63. When the shaft is at rest the stator 26 is urged to the left by the static fluid pressure forces acting on its end faces 36 and 37 and by the spring 33 so that the ring 43 is in sealing contact with the rotor 45. When the pump is started the pressure at the eye 49 of the impeller formed by the blades 47 and thus the pressure in the chamber 34 decreases with shaft speed until at a predetermined speed (which is less than the normal running speed) the pressure force acting across the stator is reversed and overcomes the spring 33 so that the stator is moved to the right as shown in Fig. 3. Leakage of fluid through the gap between the ring 43 and the rotor 45 is opposed by fluid pumped by the rotors 60 and 80 from the chamber 107 to the impeller eye 49 and, assisted by the blades 47, to the chamber 106.