EFV Series Adjustable Excess Flow Valve

EFV series: adjustable safety against excess flow

The EFV adjustable excess flow valve acts as a reliable guardian of your gas or liquid flow. Because technicians can adjust the shut-off point externally via an adjusting screw, this valve offers huge flexibility for systems with variable process conditions. The valve is also available with different reset options, so it fits seamlessly with your safety protocol.

Why the EFV series is unique

Thanks to the combination of adjustability and a robust mechanical design, engineers use the EFV adjustable excess flow valve in the most challenging environments. The key features are:

• Field-adjustable: easily change the switch point from the outside without opening the line.
• Automatic reset: the "controlled bleed" model resets itself as soon as the pressure is equalised.
• Positive shut-off: choose an elastomer seat for a completely gas-tight (bubble-tight) shut-off.
• Optional switching: extend the valve with a reed switch for direct signalling to your PLC.
• High-grade materials: available in brass or 316 stainless steel for maximum durability.

Operation and adjustment

The operating principle of the EFV series is based on magnetic attraction and pressure difference:

1. Magnetic balance: an internal magnetic piston is held in place by an external adjusting screw magnet.
2. Actuation: as soon as the pressure difference across the piston becomes too large due to excessive flow, the flow overcomes the magnetic force.
3. Shut-off: the piston shoots to the seat and immediately blocks the outlet port. This immediately stops the uncontrolled outflow.
4. Adjustability: turning the screw changes the distance between the magnets and thus the flow level at which the valve intervenes.

Technical specifications EFV series

Fields of application

Engineers often integrate the EFV adjustable excess flow valve into systems where the safety of people and the environment comes first:

• Gas analysers: protection against leakage of toxic or flammable gases.
• Hydraulic systems: prevention of oil loss in case of hose rupture.
• Fitting and regulator protection: immediate stop in case of component failure.
• Process chemistry: automatic shut-off in case of uncontrolled reactions or leaks.

Want to know which model best suits your specific flow rate and medium? Our specialists are happy to help you with the right sizing. Visit the ChemTec website for more information.