Is the safety valve calibrated before undergoing a leak test along with the pressure vessel?
Thread Content
1. Is the safety valve calibrated before undergoing a gas-tightness test along with the pressure vessel? 2. Is re-calibration required if the operating pressure of a safety valve is adjusted after it has been calibrated?
1. Required； 2. Not required ；
Thank you! Regarding Article 2, if the operating pressure of a safety valve is adjusted after it has been calibrated, this essentially means that the calibration is no longer valid; then why is recalibration not required?
1. Under normal circumstances, when pressurizing a pressure vessel, a blind flange is installed in front of the safety valve inlet valve. 2. If it’s a state-owned enterprise, calibration can be done again (state-owned enterprises have plenty of money); if it’s a private enterprise, no calibration is necessary. 3. The re-seating of the safety valve after it opens does not affect the opening pressure.
Theoretically, it isn’t necessary, as pressure testing is carried out without using the safety valve. However, quality supervision agencies usually check whether the safety valve is still within its inspection period, so it still needs to be verified
Can your safety valve activate when airtight?
When testing pressure vessels for airtightness, safety valves must be installed in accordance with the requirements of relevant regulations; the setting pressure of these safety valves should be determined based on the vessel’s maximum allowable operating pressure. During testing, the safety valve must not activate; otherwise, how can the activation test be carried out?
A safety valve is not a rupture disc; its activation and reseating are normal operations, and it will not get damaged
When the container is subjected to a gas-tightness test with safety accessories, the opening pressure of the safety valve needs to be increased in order to ensure that it does not open during the test. The safety valve is installed at its designed pressure; in my opinion, after the gas-tightness test is successful, the opening pressure of the safety valve should be reduced back to the designed value. Therefore, I would like to ask whether recalibration is necessary
A gas-tightness test is carried out with a safety valve; the maximum allowable operating pressure must be indicated in the diagram. The setting pressure of the safety valve should be between the design pressure and the maximum allowable operating pressure. By doing this, there is no need to adjust the safety valve again for the purpose of ensuring gas-tightness (of course, it is not appropriate to have the manufacturer perform such adjustments). If it is necessary to restore the setting pressure to the design value, then re-testing is required.