How is the steam discharge volume of the boiler’s exhaust valve to the atmosphere determined?

The function of the boiler’s exhaust valve to the atmosphere is to allow for manual opening in cases where the boiler experiences overpressure and the safety valve does not function. Ordinary valves require a person to climb to the top of the boiler to operate them. Electric valves can be opened by pressing the button on the electrical control cabinet. The steam discharge capacity of the boiler’s exhaust valve to the atmosphere should be determined such that the amount of steam passing through it and the exhaust pipe at the boiler’s maximum operating pressure is greater than the boiler’s maximum possible evaporation rate.

There is a calculation method for the discharge volume of the safety valve on the steaming equipment. . I’m not sure if it’s possible to use the calculation method for the exhaust capacity of safety valves to carry out the calculation. . There is a formula for calculating the corresponding saturated steam enthalpy at the highest operating pressure, based on the exhaust area. Calculation of the safety valve discharge volume (Regulations for Safety Inspection of Steam Boilers): 1. Diameter of the safety valve throat, d in cm – determined from the safety valve specifications; for A48Y-16C, DN50, this value is 3.2. 2. Flow area of the safety valve, A in mm² – calculated as πd²/4 = 3.14×32²/4 = 803.8. 3. Number of safety valves, n – determined during design; in this case, it is 1. 4. Rated evaporation capacity of the boiler, D in Kg/h – also determined during design; in this case, it is 1000. 5. Steam pressure at the inlet of the safety valve, Ps in MPa – calculated as 1.04×P; with P=1.0, this value is 1.04. 6. Saturated steam enthalpy at the rated outlet pressure, i in KJ/Kg – obtained by referring to the steam enthalpy values at P=1.0, which is 2779.7. 7. Coefficient for adjusting the specific volume of saturated steam, K – according to Article 134 of the steam boiler regulations, this value is 1.0. 8. Theoretical discharge volume of the safety valve, E in Kg/h – calculated as 0.235A(10.2Ps + 1)K; plugging in the values gives 0.235×803.8×(10.2×1.04 + 1) ≈ 2193. 9. The requirement is that E ≥ D; since 2193 > 1000, the condition is satisfied

The vent valve is generally operated based on the pressure in the steam main and the overall steam load; it is required that the steam pressure be lower than that in the main pipe. If this pressure exceeds the specified level, the operator can activate the vent valve to release excess steam. The vent valve can be electric or pneumatic, and ours is electric