With the development of social economy, the use of corrugated pipe valves, steam valves, thermal oil valves, pneumatic valves and other valves is becoming increasingly widespread. There are various types of valves used in pipelines, with different structures, and they are the most easily damaged pipeline accessories. The maintenance of each type of valve should be carried out according to the specific structure.
1. Bellows gate valves, bellows globe valves, steam valves, thermal oil valves, and ordinary valves. The valve body and valve cover are the outermost closed shell of the valve, which is used 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 valve cover require a certain level of strength and stiffness, and their damage is mainly caused by local defects caused by medium corrosion, erosion, and mechanical damage. When wall thinning is caused by corrosion or erosion, which affects their strength and stiffness, they cannot be repaired and should be replaced.
During maintenance, the valve body and valve cover should first undergo a hydraulic strength test, and then be tested for tightness using water, compressed air, kerosene, or other media The defects of the valve body and valve cover are generally repaired by welding, and corresponding welding rods and welding processes are selected according to different materials Before welding repair, the defective metal should be cleaned thoroughly, and after welding repair, inspection and repair should be carried out to eliminate stress.
2. Bellows gate valves, bellows globe valves, steam valves, thermal oil valves, and ordinary valve packing chambers. The maintenance of the packing chamber includes packing replacement and inspection and repair of the packing box. When selecting packing, the use conditions and medium conditions must be considered. Generally, oil impregnated asbestos packing is suitable for 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 graphite asbestos packing with steel wires can withstand better pressure. High temperature and frequently changing media can use asbestos and lead packing. Strong corrosive media can use PTFE asbestos packing or PTFE weaving.