Dual diameter valve stem packing
US4570942A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1985 |
| Grant date | Feb 18, 1986 |
| Priority date | — |
| Expiry date | Apr 22, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S277/914
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A "fire-resistant" packing arrangement (30) for use with linear motion or rotary motion shafts (20) characterized by a stepped dual diameter packing chamber provided by successive enlargements of the stem bore (22). A primary packing assembly (31) disposed in the chamber section (20b) of smaller diameter and cross-sectional areas and located nearest the fluid pressure provides for sealing under normal temperature and operating conditions. A secondary packing assembly (32) in the larger diameter chamber section (20c) and fabricated of "high temperature" materials is adapted to maintain sealing effectiveness in the event of abnormally high temperatures. A packing support ring (35) disposed in the larger diameter chamber section (20c) intermediate the two packing assemblies and supportable on the shoulder (62) provided by the stem bore enlargement, supports the secondary packing (32) and in the event of a decomposition of the primary packing (51) induced by extreme temperature conditions permits the secondary "high temperature" packing to maintain a seal. A packing retainer ring (38) located at the outer end of the packing arrangement as an outer packing stop is axially adjustable to …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.