With the development of social economy, the use of valves is more and more widespread. The valves used in pipelines are various in variety, different in structure, and are the most vulnerable pipeline accessories. The repair of each valve should be carried out according to the specific structure. There are many kinds of valves used in pipelines with different structures, and they are also the most vulnerable pipeline accessories. The repair of each valve should be carried out according to the specific structure.
1. The repair body and cover of the valve are the most external enclosed shell of the valve to withstand the pressure of the medium, the additional force during operation, the weight of other parts of the valve, and the tightness of flanges or threads at the joint. The body and cover require certain strength and stiffness. Their damage is mainly caused by medium corrosion, erosion and mechanical damage. If the wall is thinned by erosion and the strength and stiffness of the wall are affected, it can not be repaired and should be replaced.
When repairing, the valve body and cover should be tested by hydraulic strength test first, and then by water, compressed air, kerosene or other media to check their tightness. Defects of valve body and cover are usually repaired by welding method. Corresponding welding rods and welding technology should be selected according to different materials. Defected metal should be cleaned before welding, and checked and repaired after repairing, and stress should be eliminated.
2. The overhaul of packing chamber includes the replacement of packing and the inspection and repair of packing box parts. When choosing fillers, the use conditions and medium conditions must be considered. Generally speaking, oil-invaded asbestos panels are suitable for air, steam, water and heavy oil products at a certain temperature. Graphite asbestos panels can be used under high temperature and pressure conditions, especially those with steel wires. Graphite asbestos panels have better pressure resistance. Medium with high temperature and constant temperature can be packed with asbestos and lead. Strong corrosive medium can be knitted with polytetrafluoroethylene asbestos or polytetrafluoroethylene.