Discharge volume of the steam safety valve

Even when using saturated steam for heating, there is still a risk that pressure may exceed the design value due to system failures or abnormal conditions; therefore, it is necessary to install safety valves. For superheated steam, its higher temperature makes it more prone to overpressure, so installing a safety valve is a very important safety measure. .

Under saturated steam conditions, the pressure can reach at most the saturation pressure; then why does overpressure occur?

I think it is also necessary to take into account the pressure and temperature of the upstream steam main. Generally, pressure regulators are installed on the steam branches used for heating after they branch off from the main pipe, and safety valves are placed on subsequent pipes to prevent failures in the pressure reduction devices from preventing them from performing their function of reducing pressure

Although saturated steam theoretically reaches its maximum pressure, in actual operation, local pressures may rise above the design pressure due to various factors such as system equipment failures, operational errors, valve malfunctions, and pipeline blockages. Furthermore, the steam inside the heat exchanger may experience pressure buildup due to issues such as heat accumulation and poor flow, which can also lead to overpressure conditions. Therefore, even when using saturated steam, a safety valve should be installed for safety reasons to prevent accidents. .

This post was last edited by pzhmotor on 2024-8-30 at 14:50. It is suggested that the original poster look up the definitions of saturated steam and superheated steam. The pressure of steam is independent of its state; multiple safety valves are also installed on low-pressure saturated steam boilers, as there is a risk of overpressure due to fluctuations (decreases) in steam demand and rising bed temperature. In extreme cases, even without turning on the boiler, just applying water pressure can cause the safety valve to activate. “The “saturation pressure” can be 0.4, 0.5, or 0.8 Mpa; the temperature and pressure of saturated steam are related to each other, with different temperatures corresponding to different pressures. The front end of the steam main is connected to the steam generator (boiler); the steam pressure at the boiler’s outlet is relatively high. (Superheated steam must pass through a temperature and pressure reduction device in order to become low-pressure saturated steam.) Under normal operation, the pressure remains relatively stable within a certain flow range. However, when the demand from the users connected to the branch pipes suddenly decreases, it can cause a sharp increase in the pressure throughout the entire steam distribution network. If a safety valve is not installed to allow for timely venting of steam... Similar to pressure air systems, safety valves need to be installed on air compressors, air storage tanks, and the air storage tanks at the user end as well. Safety valves are not installed on steam pipes; they are usually installed on equipment such as split cylinders, steam collectors, and temperature-reducing pressure regulators.

Saturated steam also comes through the pipeline network. If the source is under overpressure, the pipeline network may also be under overpressure. When the pipeline network is under overpressure and adjustments cannot be made in time, the equipment will end up under overpressure.

Indeed, such a safety valve is indispensable