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I. pay attention to inspection before installation

1. Carefully check whether the valve model and specification meet the drawing requirements.

2. Check whether the valve rod and disc are opened flexibly and whether they are stuck or skewed.

3. Check whether the valve is damaged and whether the thread of threaded valve is correct and complete.

4. Check whether the combination of valve seat and valve body is firm, and whether the connection between valve disc and valve seat, valve cover and valve body, and between valve stem and valve disc.

5. Check whether the valve gasket, packing and fastener (bolt) are suitable for the requirements of working medium property.

6. The old or long-standing pressure reducing valve shall be disassembled, and the dust, sand and other debris shall be cleaned with water.

7. Remove the through port cover and check the sealing degree. The valve disc must be closed tightly.

II. Pay attention to the general provisions of installation

1. The installation position of the valve shall not hinder the operation, disassembly and maintenance of the equipment, pipeline and valve body, and the beauty of the assembly shape shall be considered.

2. For the valve on the horizontal pipeline, the valve stem shall be installed upward or at a certain angle, and the handwheel shall not be installed downward. The valve, stem and hand wheel on the high altitude pipeline can be installed horizontally, and the chain at the vertical low position can be used to remotely control the opening and closing of the valve.

3. The arrangement is symmetrical, neat and beautiful; the valve hand wheel on the riser is the most suitable for operation with chest height, generally 1.0-1.2m from the ground, and the valve rod must be installed along the direction of the operator.

4. The valves on the parallel stand pipe shall have the same elevation of the center line, and the clear distance between the hand wheels shall not be less than 100mm; the valves on the parallel horizontal pipe shall be staggered to reduce the pipe spacing.

5. When heavy valves are installed on water pump, heat exchanger and other equipment, valve support shall be set; when frequent operation and installed on valves more than 1.8m away from the operation surface, fixed operation platform shall be set.

6. If there is an arrow mark on the valve body, the direction of the arrow is the flow direction of the medium. When installing the valve, make sure that the arrow points in the same direction as the medium flow in the pipeline.

7. When installing flange valve, ensure that the two flange end faces are parallel and concentric with each other, and do not use double gasket.

8. When installing threaded valve, in order to facilitate disassembly, one threaded valve shall be equipped with one union. The setting of flexible joint shall consider the convenience of maintenance, generally water flows through the valve first and then through the flexible joint.

III. pay attention to the following details

1. The valve body material is mostly made of cast iron, which is brittle, so it shall not be impacted by heavy objects.

2. When handling the valve, it is not allowed to throw it at will; when lifting and hoisting the valve, the rope shall be tied on the valve body, and it is strictly prohibited to tie it on the hand wheel, valve rod and flange bolt hole.

3. The valve shall be installed in the most convenient place for operation, maintenance and repair, and it is strictly prohibited to be buried underground. Inspection chamber shall be set for the valve on the pipeline directly buried and in the trench to facilitate the opening, closing and adjustment of the valve.

4. Ensure that the thread is intact, and wrap hemp, lead oil or polytetrafluoroethylene raw material tape on the thread. When screwing, use a wrench to clamp the hexagonal valve body screwed into one end of the pipe.

5. When installing the flange valve, pay attention to tighten the connecting bolts along the diagonal direction, and use even force when screwing to prevent the gasket from running off or causing deformation and damage to the valve body.

6. The valve shall be kept closed during installation. For the threaded valve close to the wall, it is often necessary to remove the valve stem disc and hand wheel to screw it. During disassembly, the valve shall be disassembled after turning the hand wheel to keep the valve open.