Release Check Valves

Release check valves employ a normally closed valve to seal against pump vacuum without leaking. When a compressed air supply is applied, the release valve shifts to open at only 5 psi (0.3 bar) so that a full-flow burst of air can quickly dissipate (blow-off) system vacuum. Once shifted, the valve remains open. When the compressed air source is removed, the valve automatically resets to a closed position. Release check valves should be used for high-flow vacuum release applications such as those involving vacuum reservoirs or larger vacuum pumps.
We also offer a release check valve with a .040 in (1 mm) balancing orifice to meter the air flow when multiple release check valves are supplied air from the same blow-off control valve. Without the balancing orifice in each release check valve, the air would follow the path of least resistance. This would starve some release check valves of air while others would have a flow many times greater than necessary
Competitor products are simply check valves with a 30 – 40 psi (2 – 3 bar) cracking pressure. The high cracking pressure is necessary to insure a tight seal against vacuum developed by the pump. When a compressed air supply is applied to open the valve for blow-off, the internal spring immediately tries to