Safety valve calculation
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The maximum discharge pressure Pf of the safety valve is, in the old version of GB150, defined as the design pressure plus 0.1 plus the overpressure limit. In the new version of 150, section B.2.4 specifies that the maximum discharge pressure refers to the highest pressure at the inlet of the discharge device during the pressure relief process; according to the SW6-2024 software, Pf equals the set pressure plus 0.1 plus the overpressure limit. The new version of 150 does not provide details regarding the calculation method for Pf, so any insights are welcome.
The new version of GB150 does not specify a precise formula for calculating the maximum discharge pressure Pf of safety valves. However, in general engineering practice, the maximum discharge pressure is usually determined as the set pressure plus the allowable overpressure limit. That is: Maximum discharge pressure Pf = Set pressure + Allowable overpressure limit. The allowable overpressure limit is typically 10% of the set pressure or 0.1 MPa, whichever is greater. The calculation method used by SW6-2024 software (set pressure + 0.1 + overpressure limit) is a relatively conservative approach; in actual engineering applications, the value can be determined based on specific operating conditions and design requirements. .
For the new version SW6-2024, is the excess limit 0.1 of the design pressure or 0.1 of the set pressure?
According to Table B.1 (page 25) of GB/T 150.1-2024, it is the 10% design pressure, not the 10% set pressure? If the design pressure and the set pressure are different, for example, if the design pressure is 1.6 MPa while the set pressure is 1.5 MPa, how do people proceed in such cases? Please share your opinions; thank you.