A screening method for pressure locking and thermal binding of gate valves
- VECTRA Technologies, Inc., San Ramon, CA (United States)
A screening method is described to evaluate the potential for valves failing to open due to disc binding. Binding of the valve disc in the closed position due to high pressure water trapped in the bonnet cavity (pressure locking) or differential thermal expansion (thermal binding) represents a potential mechanism that can prevent safety-related systems from functioning when called upon. The method applies simple-to-use criteria to a given valve design, component geometry, materials, and operational transients to determine the susceptibility of the valve to fail due to disc binding. The method is illustrated for a gave valve in a high temperature steam line and parameters are defined for quantitative evaluation of relative significance of the mechanisms that may contribute to valve failure due to disc binding. The paper is organized into four parts. First part discusses the physical mechanisms that cause disc binding. Second part describes the mathematical equations. Third part illustrates the methodology for a flexible wedge gate valve gate valve. Fourth part discusses the conclusions.
- OSTI ID:
- 78297
- Report Number(s):
- CONF-941007-; ISBN 0-7918-1385-1; TRN: IM9531%%348
- Resource Relation:
- Conference: 1994 international joint power generation conference, Phoenix, AZ (United States), 2-6 Oct 1994; Other Information: PBD: 1994; Related Information: Is Part Of Heat exchange equipment and valve design and operability improvement. NE-Volume 14; Singh, K.P [ed.] [Holtec International, Cherry Hill, NJ (United States)]; Niyogi, K.K. [ed.]; PB: 92 p.
- Country of Publication:
- United States
- Language:
- English
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