Do you know the maintenance of the stop valve?
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Release Time：2021-05-21
Repair of external valve leaks. When the packing gland is relatively loose and leaks due to packing wear, the valve can be closed and the packing gland can be tightened again. If the method of pressing the packing gland cannot eliminate the leakage, the packing loses its elasticity and has no compensation ability, and the packing should be replaced completely.
(1) Repair of external leakage of the valve.
When the packing gland is relatively loose and leaks due to packing wear, the valve can be closed and the packing gland can be tightened again. If the method of pressing the packing gland cannot eliminate the leakage, the packing loses its elasticity and has no compensation ability, and the packing should be replaced completely.
When compacting the packing, the gland bolts shall be tightened symmetrically to avoid tilting of the gland and leave a gap for compacting. While pressing the packing, the valve stem should be rotated to make the packing around the valve stem uniform and prevent the pressure from being too dead, so as not to affect the rotation of the valve stem, increase the wear of the packing and shorten the service life.
Stem surface scratches, so that the medium is easy to leak, should be processed to eliminate the stem surface scars before use.
For the external leakage at the flange connection, if the gasket is damaged, it should be replaced; if the gasket material is not properly selected, the material that can meet the use requirements should be selected; if the flange sealing surface is of poor processing quality, the flange sealing surface must be removed and reprocessed until it is qualified.
In addition, the proper tightening of flange bolts, the correct configuration of the pipeline, to avoid excessive additional load at the flange connection, are conducive to preventing leakage at the flange connection.
(2) repair of internal leakage of the valve.
The repair of internal leakage is to eliminate the damage of the sealing surface and the loose root of the sealing ring (when the sealing ring is fixed on the disc or valve seat by pressing method or thread). If the sealing surface is directly processed on the valve body and disc, there is no problem of lax root and leakage.
When the sealing surface is seriously damaged and the sealing surface is formed by the sealing ring, the old ring should be removed and a new sealing ring should be provided. If the sealing surface is directly processed on the valve body, the damaged sealing surface should be first released, and then the new sealing ring or the processed surface should be ground into a new sealing surface.
When the sealing surface scratches, bumps, crush, dents and other defects depth is less than 0.05mm, can be eliminated by grinding.
If there is leakage at the root of the sealing ring, when the sealing ring is fixed by pressing, the PTFE tape or white thick paint can be placed on the bottom of the valve seat or disc sealing ring groove, and then the sealing ring can be pressed in to fill the root of the sealing ring; when the sealing ring is fixed by threads, the PTFE tape or white thick paint should be placed between the threads to prevent fluid leakage from the threads.
(3) Repair of valve corrosion
Under normal circumstances, the body, the valve cover uniform corrosion, and the stem is often pitting. When repairing, the corrosion products should be removed first. The valve stem with pitting pits should be processed on the lathe to eliminate the depression, and the filler containing corrosion inhibitor should be used instead, or the filler should be cleaned with distilled water to remove the ions that corrode the valve stem.
(4) Seal Surface Scratches Repair
Valve use, should try to prevent the sealing surface scratch, close the valve torque can not be too large. If the sealing surface scratches can be eliminated by grinding.
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