Bellows seal arrangement
US4889350A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 1, 1988 |
| Grant date | Dec 26, 1989 |
| Priority date | — |
| Expiry date | Jun 1, 2008 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16J15/363
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A bellows seal arrangement (50) seals a rotating shaft (30) passing through a housing wall (32). The seal uses two bellows (56, 58) of different effective diameters (B, C) that are connected in series by a coupling member (60). The series-connected bellows (56, 58) are fixed to the housing at one end and carry a seal insert (54) at the other providing a seal interface with a seal face member (38) rotating with shaft (30). The coupling member has bridging portions (62, 64) extending parallel to the bellows and spaced from respective stop surfaces (66, 68). Both bellows are responsive to the external pressure (P2) and to the internal (shaft side) pressure (P.sub.1). An excess of either pressure causes the larger effective diameter bellows (56) to expand or contract whereby one of the bridging portions (62, 64) abuts its stop surface (66, 68) to render one or other bellows inactive. By selection of the effective diameters (B, C) of the bellows (56, 58) relative to the internal and external diameter (A, D) of the seal interface the seal interface can be doubly-balanced to any desired degree with respect to both the internal (P1) and external (P2) pressures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.