| 摘要 |
A shaft seal is disclosed comprising a sealing element (2), a rotary sealing part (4) mounted coaxially with the sealing element and forming therewith a contactless primary seal between opposed faces of the sealing element (2) and rotary sealing part (4) to substantially prevent fluid flow across the primary seal from a high-pressure radial side to a low-pressure radial side, a seal housing (8), a pusher sleeve (9) disposed, between the seal housing and the sealing element, coaxially with and in contact with the sealing element (2), biasing means (10) urging the pusher sleeve (9) away from the seal housing (8) and against the sealing element (2) to urge the sealing element axially towards the rotary sealing member (14), and a first sealing member (12) disposed about the pusher sleeve (9) and located, in a channel (14), in communication with the high-pressure radial side to provide a secondary seal for the pusher sleeve (9) between the high-pressure and low-pressure radial sides. An auxiliary sleeve (20) is disposed around the pusher sleeve (9) coaxially therewith and maintained in sealing contact with the pusher sleeve (9) by the first sealing member (12). A tertiary seal (16) is provided in communication with the high-pressure radial side and formed between transverse and faces of the auxiliary sleeve (20) and seal housing (8). The auxiliary sleeve (20) becomes deformed under high operating fluid pressures in a manner conforming with that of the pusher sleeve (9), thereby reducing the risk of the sealing member (12) being blown out.
|
