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1. Constant pressure of safety valve
When the static pressure at the inlet of the safety valve reaches this value, the safety valve will act immediately. 2. Maximum allowable working pressure It refers to the maximum pressure that the top of the container can bear at the designed temperature. This pressure value is determined according to the normal thickness, metal corrosion margin, load and pressure in the equipment calculation. The maximum allowable working pressure is the basis of setting the safety valve pressure and protecting the equipment. The maximum allowable working pressure is usually greater than the design pressure, but when the maximum allowable working pressure cannot be determined, the maximum allowable working pressure must be equal to the design pressure. 3. Accumulation It refers to the pressure which exceeds the maximum allowable working pressure of the container during the discharge process of safety valve, expressed by pressure unit or percentage of the maximum allowable working pressure or design pressure. 4. Overpressure The pressure exceeding the set pressure of the safety valve is expressed by the unit of pressure or the percentage of the set pressure. When the maximum allowable working pressure of the pressure vessel is equal to the set pressure of the safety valve, the overpressure and accumulation value are the same. 5. Maximum allowable accumulation of pressure The system is the sum of maximum allowable working pressure and maximum allowable accumulation of safety valve. 6. Back pressure It is the pressure existing at the exit of the safety valve due to the pressure of the discharge system, and the back pressure can be fixed or changeable. Back pressure is the sum of additional back pressure and accumulated back pressure. 7. Additional back pressure When the safety valve is not started, the static pressure existing in the safety outlet due to the discharge of other valves may be fixed or changeable. 8. Accumulation back pressure When the safety valve is opened, the pressure in the main pipe is increased due to the emission. 9. Back seat pressure The difference between the set pressure and the closing pressure of the safety valve is expressed as the percentage of the set pressure or the unit of pressure. 10. Operating pressure The pressure of the container during normal operation. Pressure vessels are usually designed with maximum allowable working pressure. It provides appropriate margin for operating pressure to prevent the safety valve from opening unconditionally. 11. Discharge condition Used to indicate the inlet pressure temperature when the safety valve overpressure. The discharge pressure is equal to the set pressure of the safety valve plus overpressure. The discharge temperature is the fluid temperature under the discharge condition, which may be higher than or lower than the operation temperature. |
