Steam Boiler Safety Valve Selection principle 1. Steam Boiler Safety Valves, generally open full-open spring safety valves 0490 series; 2. Safety valves for liquid media are generally of the 0485 series of micro-open spring safety valves. 3. Safety valves for air or other gaseous media are…
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Steam Boiler Safety Valve
Selection principle
1. Steam Boiler Safety Valves, generally open full-open spring safety valves 0490 series;
2. Safety valves for liquid media are generally of the 0485 series of micro-open spring safety valves.
3. Safety valves for air or other gaseous media are usually full-open spring safety valves.
4. Safety valves for liquefied petroleum gas trucks or liquefied petroleum gas Railway Tankers generally use full-open internal safety valves.
5. Pilot safety valve is generally used for the exit of oil production wells.
6. High-pressure bypass safety valves for steam power generation equipment are generally selected as pilot safety valves with dual functions of safety and control.
7. If regular opening test is required, the safety valve with lifting wrench should be selected. When the medium pressure reaches 75% of the opening pressure, the lifting wrench can be used to lift the disc slightly from the seat to check the flexibility of the safety valve opening.
8. If the medium temperature is high, in order to reduce the temperature of the spring chamber, the safety valve with radiator should be selected when the temperature of the closed safety valve exceeds 300 ~C and that of the open safety valve exceeds 350 ~C.
9. If the back pressure at the outlet of the relief valve is variable and the change exceeds 10% of the opening pressure, the bellows relief valve should be selected.
10. If the medium is corrosive, the bellows safety valve should be selected to prevent the failure of important parts due to the corrosion of the medium.
11. Safety valve installation and maintenance should pay attention to the following matters: construction, installation points 1), installation location, height, import and export direction must meet the design requirements, pay attention to the direction of medium flow should be consistent with the direction of arrow marked by the valve body, and the connection should be firm and close. 2) Appearance inspection must be carried out before the valve is installed. The nameplate of the valve should conform to the current national standard “General Valve Mark” GB 12220. For valves with working pressure greater than 1.0 MPa and cutting off effect on main pipe, strength and tightness test should be carried out before installation, and the valves can be used only after they are qualified. In the strength test, the test pressure is 1.5 times of the nominal pressure, and the duration is not less than 5 minutes. The valve shell and packing should be qualified without leakage. The test pressure is 1.1 times of nominal pressure in tightness test, and the test duration meets the requirements of GB 50243. 1. All kinds of safety valves should be installed vertically.
12. There should be no resistance at the exit of safety valve to avoid pressure.
13. Safety valve shall be specially tested before installation and its sealing shall be checked.
14. Safety valves in use should be inspected regularly.