Velan, Inc. Dual-plate Check Valves

Retainerless dual-plate check valves for a broad range of applications. Features and benefits • BODY SURFACE WITH UNINTERRUPTED GASKET SURFACE: Proquip dual plate check valves use an internal retention method which does not encroach on the gasket sealing surface. Other retainerless designs have an internal retention method incorporating a special key and retaining screws. These components encroach on the serrated sealing face area restricting the kind of gasket that can be used. Furthermore, the screws can corrode making maintenance difficult. • INTRINSICALLY FIRE SAFE: With no drilling through the body wall, the Proquip dual plate check valve is intrinsically fire safe. • LAPPED BODY & DISC SEATS: The heart of each valve is the seat/seal interface. Proquip valves are manufactured using the most updated machining methods and equipment to achieve maximum flatness with a fine lapped finish. The end result is valves that easily meet and exceed test requirements of API 598 for metal-seated check valves. • RETAINERLESS BODY DESIGN: The Proquip dual plate check valve's body is essentially a short, heavy wall cylinder with no holes through the body wall. There is no need for retainers and leakage to the outside is impossible. Conventional dual plate check valves require holes through the body wall to facilitate the installation of the hinge and stop pins. These holes are sealed by threaded pipe plugs calledr etainers. After being in service for a period oftime, these plugs often leak due to temperature cycling, vibration and other causes. • SHOCK BUMPERS: The Proquip design utilizes heavy duty "shock bumpers"on the back of each disc. These bumpers meet when the valve is in the full open position thus preventing the discs from striking the stop pin. This arrangement reduces the shock force on the hinges, ensuring internal components have an extended cycle life with minimal wear under the most severe service conditions. • HIGH TORSION SPRING: For potentially severe applications, a high torsion spring ensures the valve closes as quickly as possible. • SUPERIOR HINGE DESIGN: In order to eliminate seat wear during the opening cycle, all dual plate check valves incorporate clearance between the hinge pin and holders, or hinge pin and disc bore. This clearance allows the disc assembly to lift off the seat prior to disc rotation preventing the heel of each disc from scraping across the body seat. Conventional designs have an oversize bore in the discs or bearings, allowing constant side to side movement of discs and increased chance of premature failure. The patented Proquip hinge pin slot allows movement in only one axis preventing premature wear. The discs, therefore, last longer and the useful life of the valve is extended.