Precautions when installing pipeline valves

1、 Be sure to check before installation

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

2. Check whether the valve stem and disc can be opened flexibly and whether there is jamming and skew.

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

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

5. Check whether the valve gasket, packing and fasteners (bolts) are suitable for the requirements of working medium properties.

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

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

2、 Pay attention to the general regulations for 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 appearance shall be considered.

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

3. The arrangement is symmetrical, neat and beautiful; For the valve on the riser, if the process permits, the valve handwheel is most suitable for operation at chest height, generally 1.0-1.2m from the ground, and the valve stem must be installed along the direction of the operator.

4. Parallel the valves on the riser. The elevation of the center line should be the same, and the clear distance between the hand wheels should not be less than 100mm; Valves on side-by-side horizontal pipes shall be installed staggered to reduce pipe spacing.

5. When installing heavy valves on water pumps, heat exchangers and other equipment, valve supports shall be set; When the valve is operated frequently and installed more than 1.8m away from the operating surface, a fixed operating platform shall be set.

6. If there is an arrow mark on the valve body of the valve, the direction of the arrow is the flow direction of the medium. When installing the valve, pay attention to make the arrow point to the same direction as the medium flow in the pipeline.

7. When installing flange valves, ensure that the end faces of the two flanges are parallel and concentric with each other, and double gaskets shall not be used.

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

3、 Pay attention to the following small details

1. The valve body of the valve 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 hand; When lifting and hoisting the valve, the rope shall be tied to the valve body and shall not be tied to the hand wheel, valve rod and flange bolt hole.

3. The valve shall be installed in the most convenient place for operation, maintenance and overhaul, and it is strictly prohibited to be buried underground. Inspection chambers shall be set for valves on pipes directly buried and in trenches to facilitate opening, closing and adjustment of valves.

4. Ensure that the thread is intact, and wrap hemp, lead oil or PTFE raw material belt 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 the force shall be even when screwing, so as to prevent the gasket from deviation or deformation and damage of the valve body.

6. The valve shall be kept closed during installation. For threaded valves close to the wall, the valve stem, disc and hand wheel often need to be removed before they can be screwed. During disassembly, the hand wheel shall be turned to keep the valve open before disassembly.