1. Leakage under pressure in packing of power plant valves
There are also many methods for dealing with external leakages of power station valves. Among them, the one with relatively good safety is the injection type under pressure, which has been concluded in detail. This method uses special fixtures and hydraulic injection tools to inject the sealant into the sealed cavity formed by the fixture and part of the outer surface of the leaking part. This treatment for dealing with leakages is more effective and takes less time. When the pressure of the injection agent exceeds the pressure of the leaking medium, the leakage will be forced to stop, and the injection agent will be transformed from a plastic body to an elastomer. At this time, the sealing structure has a certain elasticity, and there is also a certain working sealing pressure. The secondary seal is finally formed, which makes the sealing better. The following two types of sealants are used and promoted in China today:
There are also many methods for dealing with external leakages of power station valves. Among them, the one with relatively good safety is the injection type under pressure, which has been concluded in detail. This method uses special fixtures and hydraulic injection tools to inject the sealant into the sealed cavity formed by the fixture and part of the outer surface of the leaking part. This treatment for dealing with leakages is more effective and takes less time. When the pressure of the injection agent exceeds the pressure of the leaking medium, the leakage will be forced to stop, and the injection agent will be transformed from a plastic body to an elastomer. At this time, the sealing structure has a certain elasticity, and there is also a certain working sealing pressure. The secondary seal is finally formed, which makes the sealing better. The following two types of sealants are used and promoted in China today:
(1) Heat-curing sealants
The use of this sealant needs to meet certain conditions, that is, the temperature. When the temperature reaches a certain level, the sealant is an elastomer, and it is generally solid.
(2) Non-thermal curing sealants
They have a wide application and can be operated under various temperatures. It can also be installed in high-pressure injection guns. The injection and filling properties are relatively good, and the opening and closing of the valve can also be well preserved. When the wall thickness of the valve stuffing box is more than 8 mm, using injection under pressure to solve the leakage can directly set the injection hole on the wall of the valve stuffing box. The sealing cavity is the valve stuffing box itself, and the sealant can play the role of packing. Find a drill bit with a diameter of 10.5 mm or 8.7 mm in the outer wall of the valve stuffing box. It should be emphasized that this hole should not be drilled through. The reserved distance should be between 1 to 3 mm. Pull out the drill bit and tap with an M12 or MIO tap. When this work is completed, tighten the special plug valve for injecting the sealant. The valve should be in an open state. The next step is to choose a long rod drill bit, the diameter should be 3mm. The purpose is to drill through the remaining valve stuffing box wall, and the leakage will be ejected along the direction of the drill bit. There will be certain dangers when drilling, mainly because the temperature or pressure is too high, or the ejection of toxic substances will cause certain injuries to the staff, and even threaten people's life. Therefore, this cannot be ignored. It is a good control method to use a baffle before drilling.
2. Copper wire for leakages of power plant valve flanges
This method in the situation where a gap between the two flanges is small, and the pressure of the leakage medium is low. The special injection joints for bolts are placed on the removed bolts. The two are the lowest and should be greater than two. When installing the injection joint, do not tighten all the nuts, but loosen one. After installing the injection joint, tighten the nut immediately and install other injection joints. It should be emphasized here that the required joint nuts should not be loosened at the same time, because the specific pressure of the gasket will be reduced; the leakage will increase, and the leakage will blow away the gasket in severe cases. If this happens, it is difficult to take remedial measures, and the loss is incalculable.
3. Leakages of valve bodies in power plants
3.1 Bonding
If it is the pressure medium and the sand hole part with a little leakage, you can first grind the metal around the leakage point till there is metal luster, then use a taper pin to align the leakage point, and drive in with appropriate force, mainly to reduce leakage or temporarily sealing. Adhesive solidifies relatively fast, and this feature can be used to spread the adhesive around the pins to form a new solid seal structure, which can be used to prevent leaks to a certain extent. If the medium's pressure is high and the leakage is great, the sealing can be carried out. The top pressure tool is used. During the operation, the top pressure mechanism is fixed on one side of the valve, and the screw is pressed at a high speed, so that the axial direction of the top pressure screw is facing the leak point. Rotate the top pressure screw, and use the rivet at the end of the top pressure screw to well press the leaking part, which is also an effective way to prevent leakages. If the top of the rivet is smaller than the area of the leakage point, a soft metal sheet can be placed under the rivet. When the leakage stops, the metal surface around the leakage point should be cleaned in time.
3.2 Welding
If the pressure of the leaking medium of the valve body is low and the leakage is little, a nut with an inner diameter more than twice the leakage point can be used, so that the leaking medium can flow from the nut; the nut is welded on the valve body, and then provide a bolt with the same nut size. Place a rubber pad or asbestos pad at the bottom of the nut, and wrap the tape on the top of the bolt and screw it into the nut, which can effectively reduce leakages. If the medium pressure of the valve body is high and the leakage amount is great, then drainage welding is a better method. First, use a piece of iron plate with a round hole in the middle, and weld an isolation valve with the same diameter as the round hole on the round hole of the iron plate. Open the isolation valve, and align the center hole of the iron plate with the leakage point and attach it to the valve body. Let the leaking medium flow through the center hole of the iron plate and the isolation valve. In the case of a poor bonding surface, you can place rubber or asbestos pads on the bonding surface, and then weld the surrounding of the iron plate with the valve body. Close the isolation valve, so that the sealing effect that can be achieved is better.
4. Conclusion
Through the analysis, we fully understand that the power station valve is prone to external leakages. Once it occurs, if it is not dealt with in time, the loss caused is often incalculable. We must pay attention to its treatment. Relevant staff should realize the importance of their work, have a serious and responsible attitude towards their work, and treat every leak point seriously. In addition, they should also pay attention to accumulating experience in their usual work, and communicate more with their other units in order to improve their business skills. It is also necessary to continue to innovate in technology, continue to explore, and develop more and better processing methods, so that the valve can reach a state of safe operation. It is believed that with the unremitting efforts of the staff, the external leakage of the power station valves will be better dealt with, so that the valve will play a greater role in the operation of the power station.
2. Copper wire for leakages of power plant valve flanges
This method in the situation where a gap between the two flanges is small, and the pressure of the leakage medium is low. The special injection joints for bolts are placed on the removed bolts. The two are the lowest and should be greater than two. When installing the injection joint, do not tighten all the nuts, but loosen one. After installing the injection joint, tighten the nut immediately and install other injection joints. It should be emphasized here that the required joint nuts should not be loosened at the same time, because the specific pressure of the gasket will be reduced; the leakage will increase, and the leakage will blow away the gasket in severe cases. If this happens, it is difficult to take remedial measures, and the loss is incalculable.
3. Leakages of valve bodies in power plants
3.1 Bonding
If it is the pressure medium and the sand hole part with a little leakage, you can first grind the metal around the leakage point till there is metal luster, then use a taper pin to align the leakage point, and drive in with appropriate force, mainly to reduce leakage or temporarily sealing. Adhesive solidifies relatively fast, and this feature can be used to spread the adhesive around the pins to form a new solid seal structure, which can be used to prevent leaks to a certain extent. If the medium's pressure is high and the leakage is great, the sealing can be carried out. The top pressure tool is used. During the operation, the top pressure mechanism is fixed on one side of the valve, and the screw is pressed at a high speed, so that the axial direction of the top pressure screw is facing the leak point. Rotate the top pressure screw, and use the rivet at the end of the top pressure screw to well press the leaking part, which is also an effective way to prevent leakages. If the top of the rivet is smaller than the area of the leakage point, a soft metal sheet can be placed under the rivet. When the leakage stops, the metal surface around the leakage point should be cleaned in time.
3.2 Welding
If the pressure of the leaking medium of the valve body is low and the leakage is little, a nut with an inner diameter more than twice the leakage point can be used, so that the leaking medium can flow from the nut; the nut is welded on the valve body, and then provide a bolt with the same nut size. Place a rubber pad or asbestos pad at the bottom of the nut, and wrap the tape on the top of the bolt and screw it into the nut, which can effectively reduce leakages. If the medium pressure of the valve body is high and the leakage amount is great, then drainage welding is a better method. First, use a piece of iron plate with a round hole in the middle, and weld an isolation valve with the same diameter as the round hole on the round hole of the iron plate. Open the isolation valve, and align the center hole of the iron plate with the leakage point and attach it to the valve body. Let the leaking medium flow through the center hole of the iron plate and the isolation valve. In the case of a poor bonding surface, you can place rubber or asbestos pads on the bonding surface, and then weld the surrounding of the iron plate with the valve body. Close the isolation valve, so that the sealing effect that can be achieved is better.
4. Conclusion
Through the analysis, we fully understand that the power station valve is prone to external leakages. Once it occurs, if it is not dealt with in time, the loss caused is often incalculable. We must pay attention to its treatment. Relevant staff should realize the importance of their work, have a serious and responsible attitude towards their work, and treat every leak point seriously. In addition, they should also pay attention to accumulating experience in their usual work, and communicate more with their other units in order to improve their business skills. It is also necessary to continue to innovate in technology, continue to explore, and develop more and better processing methods, so that the valve can reach a state of safe operation. It is believed that with the unremitting efforts of the staff, the external leakage of the power station valves will be better dealt with, so that the valve will play a greater role in the operation of the power station.