Swing check valves
AVK offers swing check valves in DN50-600 with lever and weight, lever and spring or with closed bushings. AVK swing check valves feature very easy access to maintenance and can be installed in horisontal or vertical position.
What is a swing check valve?
A swing check valve is mounted with a disc that swings on a hinge or shaft. The disc swings off the seat to allow forward flow, and when the flow is stopped, it automatically closes against the seat to block reverse flow. Shut-off characteristics depend on the weight of the disc and the return flow.
Swing check valves with lever and weight or lever and spring
To ensure optimal performance, swing check valves are often equipped with a lever and either a weight or a spring. Swing check valves with lever and weight are appropriate for installations with an increased risk of water hammer at standard velocities. Swing check valves with lever and spring are suitable for high-pressure scenarios, insufficient back pressure or high flow velocities.
Often a lever is mounted to enable visual inspection, making swing check valves especially suitable for installation with regular personnel presence. Also, swing check valves are not completely maintenance free as they require periodic cleaning of the disc to maintain maximum performance.
Advantages of AVK swing check valves
AVK swing check valves are designed to allow for easy maintenance. The bonnet assembly, including the hinge and disc, can be removed from the body by loosening a few bolts.
Unique disc design
The light-weight disc of EPDM rubber with lip sealing and steel insert requires minimal force to open or close the valve. It is mounted within a nylon bushing, enabling slight horisontal and vertical movement to ensure a tight seal, even if minor impurities are present. The seat is placed at a 20° angle providing tightness even at low backpressure. For increased durability, the hinge of acid-resistant stainless steel is firmly tightened around the shaft with bolts to eliminate play. Additionally, the hinge can be reversed for applications with limited space.
Preventing water hammer
When mounted with lever and weight, swing check valves in small dimensions offer the possibility of priming by manually moving the lever. The weight on the lever can be adjusted to achieve a soft close against the seat as well as optimal closing speed, effectively reducing water hammer. For enhanced safety, a guard covering the lever and weight to prevent injuries is available as an optional extra. The guard can be equipped with limit switches for remote monitoring.
AVK swing check valves are available in resilient seated design in DN50-300 and in metal seated design in DN350-600.
Main features of AVK swing check valves
- Bonnet/disc design gives easy access to maintenance
- Disc with steel insert is fully vulcanized with EPDM rubber (up to DN300) ensuring optimum sealing ability
- Lip sealing on the disc ensures tightness
- Light-weight disc requires a minimum of force to open and close the valve
- The disc can move slightly horisontally and vertically for complete tightness
- Hinge tightened around the shaft with bolts to eliminate play and thus ensure durability
- Full bore ensures low head loss
- Ductile iron with epoxy coating in compliance with DIN 3476 part 1 and EN 14901
