As the fluid enters the valve, it flows through the orifice to the outlet. The orifice and tapered piston create a venturi effect, accelerating the flow through the valve. At a preset flow rate, the pressure differential offsets the spring-loading of the piston and shuts off the valve. Fluid can flow through the valve in either direction, however, the flow will be shut off in the direction indicated on the valve. Adjustment is achieved by means of an externally adjustable screw that positions the piston closer or farther away from the orifice. Turning the adjusting screw clockwise to reduce the flow area causes actuation at lower preset flows.
All LPG tank cars and transport trucks are required by law to have excess flow valves installed. In addition, state LPG regulatory bodies require excess flow valves on all LPG storage vessels storing products for domestic delivery and consumption.
- Fuel lines
- Pollution control
- Chemical processing
- Gas and hydraulic lines
- Petroleum and gas installations
