The safety valve opens before reaching the set pressure
Thread Content
The set pressure of the safety valve on the outlet pipeline of the liquid oxygen pump in our facility is 80 barg, but during operation the pressure at the pump’s outlet is around 60 barg. The safety valve often triggers before the pressure reaches 80 barg, resulting in a difference of 20 barg. What could be the cause of this issue? Thank you.
The safety valve often activates before the pressure reaches 80 barg – the spring has weakened
The spring pressure setting is not satisfactory. It is recommended to replace it with a pilot-operated safety valve.
Has this situation persisted after using it for some time, or did it happen right after it was installed? It shouldn’t differ by so much though. If it’s a quality issue, then it shouldn’t fail testing at a specialized inspection facility
Have you confirmed that the pressure hasn’t exceeded the set value? Liquid oxygen will vaporize at pressures much higher than those used in the liquid phase.
When the equipment is old or the pressure set at manufacture is 60 barg
It is recommended to go to a testing facility to re-verify the set pressure of the safety valve.
Reperform the calibration, or monitor for any sudden spikes in pressure followed by a drop
It is difficult to adjust the spring pressure properly; generally, it is adjusted manually, resulting in large errors. . . . . . . . .