With the development of society and economy, the use of valves is becoming more and more extensive. There are many kinds of valves used in pipelines with different structures, and they are the most vulnerable pipeline accessories. The maintenance of each valve should be based on the specific There are many kinds of valves used in pipelines with different structures, and they are also the most easily damaged pipeline accessories. The maintenance of each valve is necessary.

1. Maintenance of valve body and bonnet The valve body and bonnet are the outermost closed shell of the valve, which are used to withstand the pressure of the medium, the additional force during operation, the weight of other parts of the valve, and the tightness of the flange or thread at the connection. force. The valve body and bonnet require a certain strength and rigidity. Their damages are mainly local defects caused by medium corrosion, erosion and mechanical damage. When the wall is thinned due to corrosion or erosion, their strength and rigidity are affected. , it cannot be repaired and should be replaced.

When overhauling, the valve body and bonnet should be tested for hydraulic strength first, and then the tightness should be checked with water, compressed air, kerosene or other media. Defects of the valve body and bonnet are generally repaired by welding, and the selection is based on different materials. Corresponding electrodes and welding process. Defective metal should be cleaned before welding repair, and inspection and trimming should be carried out after repair welding, and stress should be relieved.

2. Overhaul of the stuffing room The overhaul of the stuffing room includes the replacement of the stuffing and the inspection and repair of the stuffing box. When selecting fillers, use conditions and media must be considered. Generally speaking, oil-invaded 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 wire has better pressure resistance, high temperature and frequently changing medium can use asbestos plus lead packing, strong corrosive medium can use PTFE asbestos Packing or teflon braid.