Selection of safety valve

Time：2022/2/10 22:44:18 Category：TECHNICAL ARTICLE Source： Click：

The nominal pressure of the safety valve is determined by the operating pressure, the operating temperature range of the safety valve is determined by the operating temperature, the constant pressure range of the spring or lever is determined by the calculated constant pressure value of the safety valve, and the material and Structure type, and then calculate the throat diameter of the safety valve according to the discharge volume of the safety valve. The following are general rules for safety valve selection.

(l) Hot water boilers generally use non-closed slightly open safety valves with wrenches.

(2) Steam boilers or steam pipelines generally use non-closed full-opening safety valves with wrenches.

(3) For liquid incompressible media such as water, a closed micro-opening safety valve or a safety relief valve is generally used.

(4) High-pressure feedwater generally uses closed full-open safety valves, such as high-pressure feedwater heaters, heat exchangers, etc.

(5) Compressible media such as gas generally use closed full-open safety valves, such as gas storage tanks, gas pipelines, etc.

(6) Class E steam boilers generally use dead-weight safety valves.

(7) Pulse-type safety valves are generally used in large-diameter, large-displacement and high-pressure systems, such as temperature reduction and pressure reduction devices, power station boilers, etc., as shown in Figure 8.

(8) The built-in safety valve is generally used in train tankers, automobile tankers, and storage tanks that transport liquefied gas, as shown in Figure 4.

(9) Hydraulic safety valve is generally used on the top of the oil tank, which needs to be used in conjunction with the breathing valve.

(10) Pilot-operated safety valves are generally used for underground drainage or natural gas pipelines, as shown in Figure 6.

(11) A safety return valve is generally used on the liquid phase return pipeline at the outlet of the tank pump in the LPG station.

(12) Vacuum negative pressure safety valves are generally used in systems that may generate negative pressure or negative pressure during operation.

(13) Bellows safety valves are generally used for containers or pipeline systems with large fluctuations in back pressure and toxic and flammable.

(14) For systems with a lower freezing point of the medium, an insulation jacketed safety valve is generally used, as shown in Figure 7.