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Technical Information Fig No. 163

Valve Pic

The Type ‘MF’ Relief Valve is hydraulically operated, single seated, piston actuated, diaphragm pilot controlled and spring regulated.

Automatically relieves over-pressure in systems and diverts to holding tank, process, pump suction or atmosphere.

The diaphragm pilot control opens when the upstream pressure reaches the nominated relief setting, releasing pressure from piston chamber thereby opening main valve.  When upstream pressure falls below setting the pilot closes.  Pressure then builds up in piston chamber via internal restricting port, closing valve.

A fine mesh screen fitted to the internal port protects the restricting orifice and pilot valve from foreign particles.


End Connections 32mm, 40mm, 50mm, BSP
Working Pressure Up to 2100 kPa maximum
Adjustable Ranges 20-700 kPa
Medoum Water, oil, gas
Temp. Range 80C maximum


Body, Bonnet and Cap Bronze, AS 1565/836B
Spring Stainless Steel
Valve Carrier Brass
'O' Ring Seals Buna-N
Piston 'U' Seal Neoprene
Pilot Valve Brass
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