Fire-safe valve actuator
USRE33928E · kind E · reissue
Assignee
Inventors
Key dates
| Filing date | Aug 28, 1990 |
| Grant date | May 19, 1992 |
| Priority date | — |
| Expiry date | Aug 28, 2010 |
Classification
- Technology area (CPC —)General
Abstract
A fire-safe valve actuator which cooperates with a bolted bonnet type valve to define a bolt chamber with an exterior shroud supporting the actuator housing and providing a substantially imperfect barrier to prevent an external fire from coming into direct contact with the bolts or studs and nuts that connect the bonnet to the valve body. The bolt chamber may also be filled with an insulation material. The actuator may have a return spring connected to the actuator stem through a bearing so that the winding and unwinding of the spring does not result in any substantial torque being applied to the actuator stem. Similiarly, any diaphragm in the actuator can be connected to the actuator stem by a bearing so that rotation of the stem will not impart torque to the diaphragm. Furthermore, a stop can be provided limiting outward movement of the stem under the influence of the spring and by further providing a suitable sliding engagement between the diaphragm-actuator housing and the stem, the actuator housing and diaphragm can be readily removed from the balance of the actuator without bleeding the line pressure down.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.