Thermal power plant valves with pressure plugging technology Power plant valves are mainly used to control the operation of fluid media on various equipment and pipelines. Leakage of valves often occurs on packings, flange seals, and valve bodies. Valve leakage can cause long time Erosion of the valve stem and flange sealing surface can eventually make the valve obsolete, plus the medium fluid thermal power plant valve pressure plugging technology power plant valve is mainly used to control the operation of fluid medium on various equipment and pipelines, valves Leakage often occurs on packings, flange seals, and valve bodies. Leakage of the valve for extended periods of time can cause erosion of the valve stem and flange sealing surfaces. Eventually the valve can be scrapped, and loss of fluid in the medium can increase the power plant's consumption. , The cost rises and the economic benefits decline. If the media fluid is toxic, flammable, explosive, corrosive, etc., it will easily cause poisoning, fire, explosion and other casualty accidents and accelerate the corrosion rate of the plant equipment, shorten its service life, seriously pollute the surrounding environment, and destroy power Production damages people's health. The existence of leakage seriously threatened safety production and increased unplanned shutdowns in power plants. The following describes some valve leakage causes and plugging methods as well as methods of maintenance and maintenance of valves for reference.
1. Forms and Factors of Valve Leakage Leakage and Causes of Valve Packing During the operation of the valve, there is relative movement between the valve stem and the packing, which includes rotation and axial movement. With the increase in the number of switches, the number of relative movements also increases, as well as the effects of temperature, pressure, and the characteristics of the fluid medium, and the valve packing is the most likely to leak. It is caused by the gradual weakening of the contact pressure of the filler, the aging of the filler itself, and the loss of elasticity. At this time, the pressure medium will leak outward along the contact gap between the packing and the valve stem, and will blow out part of the packing material for a long time and flush the valve stem out of the groove, thereby expanding the leakage.
2. Flange Leakage The flange seal of the valve is mainly based on the pre-tightening force of the connecting bolt, and the gasket can reach a sufficient sealing specific pressure to prevent the leakage of the sealed pressure fluid medium. There are many reasons for its leakage. The pressing force of the sealing gasket is insufficient, and the roughness of the bonding surface does not meet the requirements. The deformation of the gasket and the mechanical vibration will cause the leakage of the sealing gasket and the joint surface of the flange. . In addition, when the bolts are deformed or extended, the gaskets are aged, the resilience is reduced, cracks, etc., can cause the flange surface to leak tightly. Flange leakage also can not be ignored man-made factors, such as the gasket biased, so that the partial pressure than the pressure less than the excessive force, exceeding the design limit of the gasket, and flange fastening process uneven force or two methods The offset of the centerline of the blue line, which causes false tightening, is prone to leakage.
3, the valve body leakage and reasons The main reason for the leakage of the valve body is due to valve casting production or forging defects caused by, such as trachoma, air holes, cracks, etc., while the fluid medium erosion and cavitation is also caused by the valve body leakage Common factors.
3.1 The principle of pressure plugging The principle of pressure plugging is based on the liquid medium in the dynamic conditions, the solid sealing material sealing mechanism is the basic basis. The method is to install a special equipment at the leakage part, utilize the chamber formed between the sealing part and the special equipment, and inject the sealant into the chamber with a special high-pressure injection glue tool, and fill the entire chamber space to squeeze the sealant. The force balances with the pressure of the leaking medium and establishes a new sealing structure to block the passages of the leaking pores and to block the leakage of the medium.
3.2 The advantages of pressure plugging reduce social and economic losses.
1. Forms and Factors of Valve Leakage Leakage and Causes of Valve Packing During the operation of the valve, there is relative movement between the valve stem and the packing, which includes rotation and axial movement. With the increase in the number of switches, the number of relative movements also increases, as well as the effects of temperature, pressure, and the characteristics of the fluid medium, and the valve packing is the most likely to leak. It is caused by the gradual weakening of the contact pressure of the filler, the aging of the filler itself, and the loss of elasticity. At this time, the pressure medium will leak outward along the contact gap between the packing and the valve stem, and will blow out part of the packing material for a long time and flush the valve stem out of the groove, thereby expanding the leakage.
2. Flange Leakage The flange seal of the valve is mainly based on the pre-tightening force of the connecting bolt, and the gasket can reach a sufficient sealing specific pressure to prevent the leakage of the sealed pressure fluid medium. There are many reasons for its leakage. The pressing force of the sealing gasket is insufficient, and the roughness of the bonding surface does not meet the requirements. The deformation of the gasket and the mechanical vibration will cause the leakage of the sealing gasket and the joint surface of the flange. . In addition, when the bolts are deformed or extended, the gaskets are aged, the resilience is reduced, cracks, etc., can cause the flange surface to leak tightly. Flange leakage also can not be ignored man-made factors, such as the gasket biased, so that the partial pressure than the pressure less than the excessive force, exceeding the design limit of the gasket, and flange fastening process uneven force or two methods The offset of the centerline of the blue line, which causes false tightening, is prone to leakage.
3, the valve body leakage and reasons The main reason for the leakage of the valve body is due to valve casting production or forging defects caused by, such as trachoma, air holes, cracks, etc., while the fluid medium erosion and cavitation is also caused by the valve body leakage Common factors.
3.1 The principle of pressure plugging The principle of pressure plugging is based on the liquid medium in the dynamic conditions, the solid sealing material sealing mechanism is the basic basis. The method is to install a special equipment at the leakage part, utilize the chamber formed between the sealing part and the special equipment, and inject the sealant into the chamber with a special high-pressure injection glue tool, and fill the entire chamber space to squeeze the sealant. The force balances with the pressure of the leaking medium and establishes a new sealing structure to block the passages of the leaking pores and to block the leakage of the medium.
3.2 The advantages of pressure plugging reduce social and economic losses.
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