Definition of the discharge pressure of a safety valve
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This post was last edited by will_lin on 2017-7-18 07:25. I would like to ask the experts here: API RP520 specifies that the discharge pressure of a safety valve equals the set pressure plus the overpressure plus atmospheric pressure. So the question is, the set pressure plus overpressure is easy to understand, but why is atmospheric pressure also added? Is it to convert it to gauge pressure? Are there other reasons? Isn’t gauge pressure used in design work?
I’ve checked the standards GB150 and GB/T12241, but I couldn’t find any clear definition; could it be that the versions I had weren’t the authentic ones?
Gauge pressure..........
In simple terms: the discharge pressure is the inlet pressure that allows the valve disc of the safety valve to reach its rated opening height (discharge volume) once the safety valve opens.
Since the discharge volume is calculated using absolute pressure, this is the absolute pressure