Very comprehensive knowledge of valve installation, which should be collected by pipeline construction units and valve practitioners

The quality of valve installation will directly affect the use of the valve in the future. Therefore, valve installation construction units and users should attach great importance to the valve installation quality. Pay attention to the following points during installation:

1. The installation of the valve should be carried out by installing the valve instruction manual and relevant regulations. During the construction process, certification and inspection are required, and the construction must be carried out carefully. Before the valve is installed, the installation should be carried out after the pressure is qualified. Check carefully whether the specifications and models of the valve are consistent with the pipeline design drawings, check whether the valve parts are intact, whether the valve opens and closes flexibly, and whether the sealing surface is damaged, etc., confirm The valve can be installed only after it is correct.

2. When the valve is installed, the valve operating mechanism is most suitable to be about 1.2 meters from the operating ground, which is flush with the chest. When the center of the valve and the hand wheel are more than 1.8 meters away from the operating ground, an operating platform should be set for the valves and safety valves that operate more frequently. For pipelines with many valves, the valves should be concentrated on the platform as much as possible to facilitate on-site operation.

3. For a single valve that exceeds 1.8 meters and is not frequently operated, sprocket, extension rod, movable platform, movable ladder and other facilities can be used. When the valve is installed below the operating surface, an extension rod should be provided, and the ground valve should be provided with a ground well. For safety reasons, the ground well shall be covered.

4. The valve stem of the valve on the horizontal pipeline should preferably be vertically upward. It is not advisable to install the valve stem downward. The valve stem is installed downwards, which is inconvenient to operate and repair, and it is easy to corrode the valve and cause accidents. Do not install the floor valve at an angle to avoid inconvenient operation.

5. Valves on side-by-side pipelines should have spaces for operation, maintenance, disassembly and assembly, and the valve handwheel spacing should not be less than 100mm. If the pipe spacing is narrow, the valves should be staggered.

Valves installed in the pump room

6. For valves with large opening force, low strength, high brittleness and heavier weight, a valve frame should be installed to support the valve to reduce the starting stress.

7. When installing the valve, use a pipe wrench for the pipe close to the valve, while an ordinary wrench is used for the valve in this province. At the same time, during installation, the valve should be in a semi-closed state to prevent the valve from rotating and deforming.

8. The correct installation of the valve should make the internal structure conform to the flow direction of the medium, and the installation form conforms to the special requirements and operating requirements of the valve structure. In particular, pay attention to valves with medium flow direction requirements should be installed in accordance with the requirements of the process piping. The layout of the valve should be convenient and reasonable, and the operator can easily access the valve. For the lift stem type valve, leave an operating space. The stem of all valves should be installed as upward and perpendicular to the pipeline as possible.

Valves installed in gas pipelines

9. For valves with threaded connection at the installation end, the depth of the threaded valve should be appropriate. Screwing too deep will compress the valve seat; screwing too shallow will affect the sealing reliability of the joint and easily cause leakage. At the same time, the thread sealing material should be tetrafluoroethylene raw material tape or sealant, and be careful not to bring the sealing material into the valve cavity.

10. For valves with flange end connections, first find the connection surface of the flange, the cover is perpendicular to the pipeline, and the bolt holes should be aligned. The valve flange should be parallel to the pipe flange, and the flange gap should be moderate, and there should be no misalignment or inclination. The gasket between the flanges should be placed in the center, not skewed, and the bolts should be symmetrically and evenly tightened. To prevent the forced connection and tightening of bolts during valve installation, resulting in an additional residual stress.

11. Before installation, thoroughly remove the dirt on the inner wall of the pipe and the external thread; remove burrs and foreign objects that hinder the flow of the medium and may affect the operation of the equipment, and blow off the dirt, residue and other debris in the pipe before connecting the pipe . Prevent damage to the sealing surface of the valve or block the valve.

12. To install the valve with the welding end connection, you should first assemble the welding ports at both ends of the valve after spot welding, open the valve, and then apply the welding seam according to the welding process. After welding, check the appearance of the weld and the quality of the internal weld. To ensure that there are no defects such as pores, slag inclusions, cracks, etc., the welds should be inspected by radiography or ultrasound when necessary.

13. When installing a heavier valve, use lifting tools or equipment. The lifting rope should be tied to the valve flange or bracket, and should not be tied to the valve handle or stem to avoid damage to the valve.

14. In addition to the above installation requirements, you should also consult the valve manufacturer# manufacturer