Adjust needle valve

Adjust needle valve

Precautions for adjusting the needle valve installation: 1) The installation position, height, and inlet and outlet direction must meet the design requirements. Note that the direction of the medium flow should be consistent with the direction of the arrow marked on the valve body, and the connection should be firm and tight. 2) Adjust the needle valve before the installation of the valve must be visual inspection, the nameplate of the valve should comply with the current standard "General Valve Mark" GB 12220. For valves with a working pressure greater than 1.0 MPa and a shut-off function on the main pipe, the strength and tight performance tests shall be carried out before installation, and shall be used after passing the test. In the strength test, the test pressure is the nominal pressure.

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Precautions for adjusting the needle valve installation:
1) Installation position, height, import and export direction must Meet the design requirements, pay attention to the direction of the medium flow should be consistent with the direction of the arrow marked by the valve body, the connection should be firm and tight. 2) Adjust the needle valve before the installation of the visual inspection must be carried out, the nameplate of the valve should comply with the current standard "General Valve Mark" GB 12220. For valves with a working pressure greater than 1.0 MPa and a shut-off function on the main pipe, the strength and tight performance tests shall be carried out before installation, and shall be used after passing the test. In the strength test, the test pressure is 1.5 times the nominal pressure, the duration is not less than 5 min, and the valve casing and the packing should be free of leakage. In the rigorous test, the test pressure is 1.1 times the nominal pressure; the duration of the test complies with the requirements of GB 50243. Selection principle: 1. In the piping system and device of low temperature medium, the low temperature needle valve with bonnet should be selected. 2. On the pipeline system of the catalytic cracking unit of the refinery, a lifter type needle valve can be selected. 3. In the equipment and piping system of corrosive medium such as acid and alkali in chemical system, it is preferable to use all-stainless steel needle valve made of austenitic stainless steel and polytetrafluoroethylene as valve seat sealing ring. 4. Metal-to-metal sealed needle valve may be used on the piping system or device of the high-temperature medium in the metallurgical system, power system, petrochemical plant, and urban heating system. 5. When the flow adjustment is required, the worm gear-driven, pneumatic or electric V-shaped opening can be selected. 6. The main line for the transportation of oil and natural gas, the pipe that needs to be cleaned, and the underground pipe, the needle valve with full diameter and all welded structure is selected; if it is buried on the ground, the full-diameter welded connection or flange connection is selected. Ball valve. 7. The conveying pipeline and storage equipment of the refined oil are selected from the flanged needle valve. 8. On the pipelines of city gas and natural gas, needle valves with flange connection and internal thread connection are selected. 9. In the oxygen pipeline system in the metallurgical system, a needle valve that has undergone strict degreasing treatment and flange connection should be used.

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