RIG PUTS PRESSURE ON RELIEF VALVES
September 1st 2005

An independently vetted test rig from Portasilo is used to evaluate the effectiveness of pneumatic pressure relief valves used in pressurised tanker filling from silos.

The rig has confirmed the effectiveness of the Portasilo PRV350 combined pressure and vacuum relief valve in avoiding over- and under-pressurisation during powder filling and emptying.

An HSE guide identified that a significant air surge could occur at the end of the filling operation. It could reach 13 000m3/h for a 2bar tanker. Portasilo constructed a test rig capable of generating such air flows in order to validate the calculated figure and to test some of the available pressure relief valves.

Tests confirmed peak air flows slightly in excess of those predicted and, according to Dennis Cook, Portasilo’s technical manager, valve after valve failed to handle the surge.

Portasilo’s PRV350 handles such air flows with minimal pressure accumulation, making it possible to maximise the set pressure and so reduce the chance of atmospheric pollution through dust release. It is available with a wide range of set pressures.

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