The diaphragm valve cover
Diaphragm valves in jet filters consist of a body, an aluminium cover, a rubber diaphragm, a spring and a pilot valve. The aluminium filter cover is the cast part that forms the pressure chamber above the diaphragm and carries the pilot valve. Bolted to the body, it clamps the diaphragm edge to form a seal.
Why cast aluminium?
- Light and strong: keeps its shape under compressed air.
- Corrosion-resistant: does not rust from moisture in the compressed air.
- Precise internal form: machined surfaces after casting let the diaphragm seat properly and direct the pilot air correctly.
When does the cover cause problems?
- A crack in the cover or broken bolt holes cause a constant air leak.
- Scratches or dents on the diaphragm seating face stop the valve closing fully.
- Damaged threads at the pilot valve connection let pilot air escape and weaken the valve.
Fitting tips
Before fitting the cover, make sure the diaphragm and spring are correctly in place. Tighten the bolts in a crosswise sequence and evenly; tightening from one side seats the cover at an angle and crushes the diaphragm edge. Check for leaks before putting the valve back into service.
Send us the cover dimensions, bolt pattern or valve make and we will supply the right aluminium cover.
