LNG shut-off valve maintenance process requirements

As we all know, the main purpose of the LNG shut-off valve is to shut off. It can also be used to roughly adjust the flow rate, but it cannot be used as a throttle valve. Its applications in power plants are very wide, especially in the smaller passages.

The LNG shut-off valve should be regularly overhauled during use to prevent accidents. The maintenance process requirements are as follows:

1. Check the valve seat and valve head sealing surface. They should be smooth and free from erosion, groove marks, pitting and other defects. If any, they should be ground or repaired according to the degree of defect.

2. Check the valve stem, and there should be no defects such as bending, abrasion, erosion, etc. The seal with the packing should be smooth and free of defects such as groove marks, and the thread on the valve stem should be free from damage, and should fit well with the nut and rotate freely, otherwise it should be repaired. The valve stem is bent within 0.1 mm, and the depth of wear corrosion pits should not exceed 0.1 to 0.2 mm.

3. Check the connection thread between the bracket and the valve seat. There should be no damage and good cooperation.

4. Check the wear condition of the transmission mechanism, the worm wheel, and the worm. The wear should not exceed one third of the tooth thickness, and there should be no cracks and poor meshing in the meshing part. Check the bearing for wear and inflexible rotation, the manual and automatic switching is flexible and reliable, and the transmission performance is good.

The above is the overhaul process requirements for the LNG shut-off valve.