Adjusting needle valve

Adjusting needle valveInstallation precautions:

1) The installation position, height, and inlet/outlet direction must meet the design requirements. Attention should be paid to the direction of medium flow, which should be consistent with the arrow direction marked on the valve body. The connection should be firm and tight.

2) Before installing the regulating needle valve, a visual inspection must be carried out, and the valve nameplate should comply with the current national standard "General Valve Marking" GB 12220. For valves with a working pressure greater than 1.0 MPa and a shut-off function on the main pipeline, strength and tightness tests should be conducted before installation, and they can only be used after passing the tests. During the strength test, the test pressure shall be 1.5 times the nominal pressure, and the duration shall not be less than 5 minutes. The valve shell and packing shall be qualified if there is no leakage. During the tightness test, the test pressure is 1.1 times the nominal pressure; The duration of the experiment meets the requirements of GB 50243.

Selection principle:

1. Low temperature needle valves with valve covers should be selected for pipeline systems and devices for low-temperature media.

2. On the pipeline system of the catalytic cracking unit in the refining unit, a lifting rod needle valve can be selected.

3. In the equipment and pipeline systems of corrosive media such as acid and alkali in chemical systems, it is advisable to use all stainless steel needle valves made of austenitic stainless steel with polytetrafluoroethylene as the valve seat sealing ring.

4. Metal to metal sealed needle valves can be used on pipeline systems or devices for high-temperature media in metallurgical systems, power systems, petrochemical plants, and urban heating systems.

5. When flow regulation is required, worm gear transmission, pneumatic or electric with V-shaped opening can be selected. 6. For the main pipelines of oil and natural gas transportation, those that need to be cleaned and buried underground, needle valves with full bore and fully welded structures should be selected; For ball valves buried on the ground, choose full bore welded connections or flange connections.

7. Flange connected needle valves are used for the transportation pipelines and storage equipment of finished oil products.

8. On the pipelines of urban gas and natural gas, needle valves with flange connections and internal thread connections are selected.

9. In the oxygen pipeline system of the metallurgical system, it is advisable to use needle valves that have undergone strict degreasing treatment and are connected by flanges.