Boiswood, a specialist distributor of components for gas and liquid control, is now supplying the CTE excess flow valve (EFV) for high pressure lines.

In the event of a line or fitting failure, excess flow enters the EFV and is directed through a right angle to the outlet port across the nose of a magnetic piston. The piston is held in position by an adjusting screw magnet. When the pressure differential created by flow across the piston is great enough, the piston slides to a seat at the outlet port. An external adjusting screw can be used to change the flow rate at which the piston actuates.

The piston creates a bubble-tight seal when it makes contact with the seat. The valve is re-opened by turning a balancing valve handle, which ports the upstream pipeline to the downstream pipeline. It resets when the pressure is equalised on each side. Normal operation is resumed by closing the balancing valve.