Conventional Reverse-Flow Check Valves

This line of valves includes the 1-in [25.4-mm]-OD BF and B-1 valves and the 1 1/2-in [38.1-mm]-OD CF and J-20 valves. These valves each have an elastomeric soft seat and stainless steel hard seat. The initial seal is between the stainless steel check dart and the soft seat. These check valves can withstand 10,000-psi differential pressure and can be converted from velocity check valves to positive check valves by adding a spring.

Reverse-flow check valves require flow to close. As the differential pressure across the check dart of the valve increases, the dart contacts the soft seat and then the hard seat to form a seal and close the check valve.