Valve maintenance skills

With the development of social economy, valves are used more and more widely. The valves used in the pipeline are various in types and structures, and are the most vulnerable pipeline accessories. The maintenance of each valve should be carried out according to the specific structure. The valves used in the pipeline are various in types and structures, and are the most vulnerable pipeline accessories. The maintenance of each valve should be carried out.
1. Maintenance of valve body and bonnet The valve body and bonnet are the outermost closed 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 tightening force of the flange or thread at the connection The valve body and bonnet are required to have certain strength and rigidity. Their damage is mainly local defects caused by medium corrosion, erosion and mechanical damage. When the wall is thinned due to corrosion or erosion, which affects their strength and rigidity, they cannot be repaired and should be replaced
During maintenance, the valve body and bonnet shall be subject to hydraulic strength test first, and then tested for tightness with water, compressed air, kerosene or other media The defects of valve body and bonnet are generally repaired by welding, and corresponding welding rod and welding process are selected according to different materials The defective metal shall be cleaned before repair welding, and shall be inspected and repaired after repair welding, and the stress shall be removed
2. Maintenance of packing chamber Maintenance of packing chamber includes packing replacement and inspection and repair of packing box parts. When selecting packing, service conditions and medium conditions must be considered. Generally speaking, oil-impregnated asbestos packing is applicable to air, steam, water and heavy oil products at a certain temperature. Graphite asbestos packing can be used under high temperature and high pressure conditions, Especially the graphite asbestos packing with steel wire is more resistant to pressure. The asbestos plus lead packing can be used in the medium with high temperature and constant temperature change. The strong corrosive medium can be used in the PTFE asbestos packing or PTFE woven