US EPA

6908555 

Journal Article 

Packing developments improve valve availability 

Aikin, J 

1994 

No 

Power Engineering
ISSN: 0032-5961 

98 

1 

29 

English 

The limited availability of asbestos packing seals from suppliers has prompted a renewed effort to find alternatives and improve valve stuffing box sealing. The first step toward leak-free valve performance is a thorough valve packing qualification procedure. A proper qualification testing regime might ensure that certain requirements are met, among them: 1. Packing rings will not induce unacceptable valve stem and stuffing box corrosion levels. 2. Packing rings will retain elasticity when exposed to reactor operating conditions. Because of recent valve actuator setup regulations, packing friction is becoming increasingly important to valve maintenance. Packing friction is calculated as the difference between measured stem thrust and the hydraulic force on the stem. Live loading is proving to be an effective way to reduce the risk of fluid loss in critical applications. The normal requirement for elasticity in packing materials can be relaxed for live-loaded packing because elasticity is provided outside the stuffing box. 

Energy; Power plants; Maintenance management; Impacts; Environmental regulations; Component parts; 8340:Electric, water & gas utilities, including waste management industry (seel also 1540); 9190:United States; 5130:Maintenance management; 1540:Pollution control (see also 8340)