Commonwealth Edison Company pressure locking test report
Pressure Locking is a phenomena which can cause the unseating thrust for a gate valve to increase dramatically from its typical static unseating thrust. This can result in the valve actuator having insufficient capability to open the valve. In addition, this can result in valve damage in cases where the actuator capability exceeds the valve structural limits. For these reasons, a proper understanding of the conditions which may cause pressure locking and thermal binding, as well as a methodology for predicting the unseating thrust for a pressure locked or thermally bound valve, are necessary. This report discusses the primary mechanisms which cause pressure locking. These include sudden depressurization of piping adjacent to the valve and pressurization of fluid trapped in the valve bonnet due to heat transfer. This report provides a methodology for calculating the unseating thrust for a valve which is pressure locked. This report provides test data which demonstrates the accuracy of the calculation methodology.
- Research Organization:
- American Society of Mechanical Engineers, New York, NY (United States)
- OSTI ID:
- 402019
- Report Number(s):
- NUREG/CP--0152; CONF-9607103--; ON: TI96013645
- Country of Publication:
- United States
- Language:
- English
Similar Records
Pressure locking test results
Results of pressure locking and thermal binding tests of gate valves