Differential/Air Check valves are placed on the outlet side of a meter system and work in conjunction with the system’s air/vapor eliminator to stop the flow of product through the meter until the air/vapor is eliminated. In order to do this, the air/vapor eliminator and the valve are piped together at installation.
Differential/Air Check valves are normally closed, but when the pump starts and pushes product into the system, the valve spring will give way to the flow pressure. In order to keep the valve closed when air/vapor is being expelled from the air/vapor eliminator, the air/vapor from the air/vapor eliminator is routed through the piping to the back side of the valve spring. The combined force of the expelled air/vapor and the strength of the spring keep the valve closed until the air/vapor is eliminated.
Materials of Construction
- Standard 2" aluminum valve is spring loaded and designed to fail closed.
- Provides a constant 15 PSI differential pressure and controls flow when vapor is sensed.
- The 511-series differential valve is available with an adjustable differential pressure setting of 5 to 16 PSI.
- Available in ductile iron or cast steel in sizes of 2", 3", 4" or 6" flanges.
- Typically used with our MS-series meters and accessories.