Safety Critical Valve Test Bench

The test procedure for this particular valve was complex; the functional test required the system to bring the pressure to a point, hold and ensure the valve is not releasing. It then needed to take the pressure to a point in the mid range of the releasing pressure band, releasing of liquid then needed to be observed. Next, the pressure needed brought up to the valve closing pressure, check that no liquid is releasing and that the valve had closed again and then this needed to be repeated with the same logic in reverse, reducing the pressure back down again.

The pressure needed to be measured in Bar(G) and accuracy was required to two decimal places with the lowest pressure required to be holding within a tolerance of 0.37 – 0.40 bar. The full test sequence in relation to pressure ramping was to be fully automated with pause points to allow operators complete the required visual checks.

Pressure ramping needed to be slow and smooth, which presented a challenge due to the lack of volume in the test valve itself coupled with the fact that liquid was the required test medium, we over came this by designing an air over liquid system which provided extremely smooth and accurate pressure control.

It was also a requirement for the manifold block – which the valve undergoing test would be fixed to inside the main interlocked test complement – was clear to allow operators visually see the liquid entering and leaving the valve. The full system needed need to be compact and designed in such a way so it could be mounted on an existing work station table.