kunshan haijin machinery co.,ltd , https://www.haijinmachinery.com
Safety valve classification and selection
1. Classification Currently mass-produced safety valve spring and rod two categories. There are also impulse-type safety valve, pilot-operated safety valve, safety switch valve, safety relief valve, static heavy-duty safety valve. Spring-loaded safety valve depends mainly on the force of the spring to work, spring-loaded safety valve has closed and not closed, the general flammable, explosive or toxic media should be used closed, steam or inert gas can choose not closed Type, in the spring-loaded safety valve with wrench and without wrench. The role of the wrench is to check the valve flap flexibility, and sometimes can also be used as a manual emergency relief pressure, as shown in Figure 3. Lever safety valve rely mainly on the leverage of the hammer work, but because of the large size of the lever safety valve often limits the scope of selection. When the temperature is high, select the safety valve with a radiator. The main parameters of the safety valve displacement, the displacement of the valve seat depends on the caliber and the valve opening height, the opening height is different, is divided into two kinds of micro-Kai and full Kai. Micro-Kai refers to the valve opening height of the valve seat throat diameter 1/40 ~ l / 20. Throttle refers to the valve opening height of the valve seat throat diameter 1/4. 2. The selection of safety valve is determined by the operating pressure of the nominal pressure of the safety valve, the operating temperature of the safety valve to determine the temperature range, the calculated value of the safety valve determines the fixed pressure spring or lever range, and then use the media to determine the safety Valve material and structure type, and then calculated according to safety valve relief valve throat diameter. The following general rules for the selection of safety valve. (L) General use of hot water boilers are not closed with micro-valve wrench safety valve. (2) steam boiler or steam pipe is generally not closed with a wrench full safety valve. (3) water and other liquid incompressible media commonly used closed micro-valve, or safety relief valve. (4) high-pressure water supply Generally closed full Kai-type safety valve, such as high-pressure water heaters, heat exchangers. (5) compressible gas and other gases generally use closed-type safety valve, such as gas tanks, gas pipelines. (6) E-class steam boilers generally use heavy-duty safety valve. (7) Large-caliber, large displacement and high pressure systems generally use pulse safety valve, such as temperature and pressure reduction devices, power plant boilers, as shown in Figure 8. (8) Transportation tanker, tank car, storage tank and other general-purpose built-in safety valve for delivering liquefied gas, as shown in FIG. 4. (9) The top of the tank with hydraulic safety valve, need to be used in conjunction with the breathing valve. (10) Downhole drainage or natural gas pipeline generally use pilot-operated safety valve, as shown in Figure 6. (11) liquefied petroleum gas station tank pump outlet liquid return pipe commonly used safety valve. (12) Negative pressure or negative pressure may occur during operation of the system is generally used vacuum negative pressure safety valve. (13) Bellows relief valves are generally used for container or piping systems with large back pressure fluctuations and toxic flammability. (14) medium freezing point lower system generally use insulation jacket safety valve.