1. Seat pressure: The disc is in contact with the valve again after discharge. That is, an inlet pressure of zero opening height.
2. Opening and closing pressure difference: the difference between opening and closing pressure and round pressure, usually expressed as a percentage of opening and closing pressure, and expressed in MPa only when the opening and closing pressure is very low.
3. Back pressure: the outlet pressure of the safety valve.
4. Rated discharge pressure: The standard specifies the upper limit of the discharge pressure.
5. Seal test pressure: the inlet pressure for the seal test to measure the leakage rate through the closed sealing surface.
6. Swing height: End the actual lift at the flap closed position.
7. Flow channel area: used to calculate the minimum cross-sectional area of the flow channel between the valve inlet and the coating surface, and the theoretical displacement without resistance.
8. Runner diameter: the diameter corresponding to the runner area.
9. Curtain area: the cylindrical or conical channel area formed between the sealing surfaces when the disc is on the valve.
10. Discharge area: The minimum cross-sectional area of the fluid passage when the valve is discharged, and for a fully actuated safety valve, the discharge area is equal to the flow passage area. For the safety valve in the United States, the discharge area is equal to the curtain area.
