The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 26, 1989
Filed:
Jun. 01, 1988
Brian R Tranter, High Wycombe, GB;
EG&G Limited, High Wycomb, GB;
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.