Swing check valves
AVK offers check valves in DN 50-600 with lever and weight, lever and spring and optionally with protection cap. AVK check valves are easy to maintain and can be installed both horizontally and vertically.
What is a swing check valve?
The basic principle of a swing check valve is a disc mounted on a hinge or a shaft. When the pressure in the pipe is high enough, the disc rises and forward flow is possible. The disc returns to its original position when pressure drops or when flow stops in the pipe system to prevent backflow. The weight of the disc and the backflow affect the closing properties of the swing check valve..
Swing check valves with lever and weight or lever and spring
To ensure optimum performance, swing check valves are often equipped with a lever and a weight or a spring. Swing check valves with lever and weight are suitable for installations with an increased risk of water hammer at standard velocities. Swing check valves with lever and external spring are suitable for systems with high pressure, insufficient back pressure and high flow velocities.
A lever is often fitted to allow visual inspection and cleaning, making swing check valves particularly suitable for installations in areas where personnel are present and the swing check valve can be cleaned periodically to maintain maximum performance.
Benefits of AVK swing check valves
AVK swing check valves are designed for easy maintenance. By loosening a few bolts, the bonnet including hinge and disc can be removed from the body and maintenance can be carried out.
Unique disc design
The lightweight disc with steel insert fully vulcanized with EPDM rubber with lip seal requires minimal force to open and close the valve. The disc is mounted in a nylon bushing, allowing slight horizontal and vertical movement to ensure a tight seal even when small impurities are present. The seat is set at a 20° angle to provide a good seal even at low back pressure. For increased durability, the hinge made of acid-resistant stainless steel is firmly bolted around the shaft to eliminate play. In addition, the hinge can be reversed for applications where space is limited.
Preventing water hammer
When mounted with lever and weight, the small size swing check valves offer the possibility to adjust the position of the weight by moving the lever manually. The weight on the lever can be adjusted to achieve a soft closing against the seat as well as an optimum closing speed to prevent water hammer. For additional safety, a protective cover is available that covers the lever and the weight to prevent injuries. The protective cover can be equipped with limit switches for remote monitoring.
AVK swing check valves are available resilient seated design in DN 50-300 and in metal seated design in DN 350-600.
Keyfeatures of AVK swing check valves
- Intelligent bonnet and disc design, easy to maintain
- Disc with steel insert is fully vulcanised with EPDM rubber (up to DN 300) for optimum sealing
- Lip seal on the disc ensures tightness
- Lightweight disc requires minimal force to open and close the valve
- Disc can move slightly both horizontally and vertically for a tight seal
- Hinge firmly bolted around the shaft to eliminate play and thus ensure durability
- Full bore ensures low pressure loss
- Ductile iron with epoxy coating according to DIN 3476 part 1 and EN 14901
