Release Check Valves

RC18A

The RC18A employs a normally closed valve to seal against vacuum pumps without leaking. When a compressed air supply is applied, the release valve shifts 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 doesn't try to close but remeains open. Once the compressed air source is removed, it automaticallu resets to a closed position. The RC18A should be used for high-flow vacuum release applications such as those involving vacuum reservoirs or larger vacuum pumps.

Competitive products are simply check valves with a 30-40 psi (2-3 bar) cracking pressure. The high cracking pressure is necessary to ensure 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 close the valve as soon as flow this has the effect of subtracting the valve cracking pressure from the blow-off air pressure. Because of this, these systems normally have to operate above 50 psi (3.3 bar) which wastes compressed air.

Maximum Pressure: 50 psi

Weight: .107 lbs (48.5 g)



RC18-040A

The RC18-040A operates the same as the RC18A but includes a 0.040" (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.

Maximum Pressure: 50 psi

Weight: .107 lbs (48.5 g)