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Throttle valve calculation, safety valve calculation, pressure before the valve in Mpa: 0.7. 1: Concepts 1. Sealing pressure: The inlet pressure when the valve is in a closed state and there is no leakage between the sealing surfaces. P depends on the design requirements of the pipeline or equipment. Pressure behind the valve: 0.62 Mpa. Opening pressure: that is, the set pressure, which is the inlet pressure at which the valve disc of the safety valve begins to rise under operating conditions. P0: Natural gas flow rate – 104 Nm3/d. Working pressure of the pipeline or equipment (gauge pressure), in Mpa; Pressure at which the safety valve opens (gauge pressure), in Mpa; Design pressure, in Mpa. For P0, this value is 0.7, with a maximum of 1.0. Sealing pressure = 0.05 × P0. For P00, the specific gravity of natural gas is 0.8; in such cases, the pressure is 1.05 times the sealing pressure. For P00.735, it’s 1.10 times the sealing pressure. For P00.77, the compressibility factor of natural gas applies. 13. Discharge pressure: This is the pressure at the valve inlet when the valve disc is fully open and the rated discharge volume is achieved. 14. Liquid: p1 = 0.90, 0.882, 0.924. Temperature before the valve: 0 K to 363 K. P1 = P0 + Pa. Accumulated pressure: For liquids, Pa = 0.2 × P0; for gases, Pa = 0.1 × P0. Gas: p1 = 0.825, 0.8085, 0.847. Diameter, in mm: 24.25, 50.14. 14. Flow area: This refers to the minimum cross-sectional area of the flow path from the valve inlet to the sealing surface of the closing element, and it is used to calculate the theoretical discharge volume without any resistance. 5. Channel diameter: The diameter corresponding to the channel area. 6. Curtain area: The area of the cylindrical or conical passage formed between the sealing surfaces when the valve disc rises above the valve seat. 7. Discharge area: The minimum area through which the fluid passes when the safety valve discharges; for fully open valves, it equals the flow channel area, and for slightly open valves, it equals the curtain area. 8. Back pressure: The pressure at the valve outlet, denoted as P2. 9. Discharge volume: The volume discharged by the safety valve at the discharge pressure. Oilfield equipment (excluding steam boilers) and pipelines, based on the total amount of material that enters as a result of the accidental closure of the outlet valves. II: Calculation of the nozzle area for fully open safety valves 1. Liquid medium: 2. Gas medium Liquid flow rate Q, in m3/h: 50 Critical flow pressure ratio: 0.054143 Liquid density correction factor Km: 1.5; 1.0–1.6 Critical flow pressure Px, in MPa: 0.044668, 0.043775, 0.045859 Liquid viscosity correction factor Kr: 1; 0.75–1.0 a) When P2