Can a negative pressure be connected to the outlet side of the safety valve?
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I would like to ask whether a negative pressure system can be connected to the outlet side of the evaporator’s safety valve? The positive pressure of the evaporator is 0.4 MPa, while that of the condenser is -70 KPa. I want the medium to enter the condenser and be condensed after the safety valve opens. Will it work? Does negative pressure have an effect on the set pressure of a safety valve?
Safety valves cannot guarantee absolute leak-free operation; does your safety valve trip frequently? The issue should be addressed from the perspective of process control; if the activation of safety valves is treated as something normal, then an accident is likely to occur soon.
It won’t jump often. It is just to prevent overpressure in the evaporator. The medium in the evaporator is flammable and explosive.
If it must be used in this way, the launch pressure should be reset. Increase the takeoff value relative to the value under normal atmospheric pressure. There is a problem here: such a setting is intended to maintain a constant negative pressure level. If that level is not maintained, overpressure will not be detected, and accidents can occur. Also, if there is no gauge pressure in front of the safety valve, it will also be evacuated. Most importantly, the activation of the safety valve is a means of pressure relief in case of an emergency; it should be activated for a short period of time only, and it should not be used as a pressure reducing valve for an extended duration. If such a requirement exists, it is most reasonable to install a self-acting control valve in front of the safety valve, setting the pressure to be slightly lower than the setting pressure of the safety valve. For reference.
It’s good to be talented and help the company save money, but make sure no problems arise
What potential harms could there be if done this way?
Spend a bit more money on pilot-operated safety valves – this way, the set pressure won’t be affected
Negative pressure should have an effect on safety valves; typically, safety valves rely on springs to set the operating pressure. There are certainly many risks, but more analysis is needed based on the industrial conditions ； What abnormalities will occur in the vacuum system if the safety valve does not return to its normal position after activating under extreme conditions? It is not recommended to do this.