Magnetic "flap" valves

[TMD]

I'm looking for a source of relief valves to control air flow at low pressures. I've seen valves that have a flap that is held closed magnetically and opens at very low pressures, 4-6" of water. Anybody have any suggestions?

 

[mc5w]

Gast Manufacturing in Michigan, U.S.A. has some vacuum and pressure relief valve that can be adjusted for your application. Look in their regenerative blowers catalogs.

Website is:

http://www.gastmfg.com

A magnet would introduce to much hyteresis between the opening and closing pressure.

Mike Cole, mc5w@earthlink.net