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SERIES FE
LOW-PRESSURE GAS REGULATOR | DESCRIPTION AND OPERATION | REV. 00
EN
Use, maintenance and warning manual
4.6.3 - RELIEF VALVE
The relief valve (A) is a safety device that is used to:
• automatically discharge a gas ow into the atmosphere through the exhaust conveyor (B), when the pressure detect-
ed downstream exceeds a pre-set value and
• to automatically return to closed position when the downstream pressure drops below the opening/discharge value.
The relief valve trips due to:
• thermal expansion of the downstream gas with no ow;
• temporary defective sealing of the plugs in the rst and second regulation stages.
NOTE!
The tripping pressure value of the relief valve is lower than the tripping pressure value of the slam-shut
valve for maximum downstream pressure.
A
B
Fig. 4.5. Relief valve