Ascending Efficiency: Rising Stem Valves in Critical Process Control
Nov 21,2023Read More
Valve internal leakage or a small amount of leakage, the first job is to tighten and fix the pressure plate of the valve body, and by increasing the bolt to strengthen the pressure plate and wedge-shaped sealing ring preload strength, which can help the plastic deformation of the sealing ring, so as to better reduce the gap between the valve body, pressure plate and sealing ring size, to avoid leakage of the valve self-sealing phenomenon. If the leakage does not change significantly when tightening and fixing the bolts, the tightening measures should be stopped immediately and other processing measures should be taken instead.
When the general purpose valve has a small internal leakage, the sealing surface or packing can be greased through the grease injection hole to temporarily alleviate the valve leakage. When it is easy to repair and maintain, the valve can be disassembled and returned to the factory for repair.
The valve self-sealing leaks need to do a good job of dismantling the valve handwheel and the valve frame, first of all, we must cooperate with the staff to grasp and adjust the site conditions, and then the valve all open, and then dismantle the bolts fixed on the valve bracket, rotate the valve frame clearly after the stem does not rise and fall changes, then start to dismantle the valve frame. After disassembling the valve frame, the valve body should be exposed in the pressure plate part of the valve, and the gap between the pressure plate and the valve body should be sealed and welded, for the consideration of sealing the leakage position after the valve frame back to the installation process, the size of the welded gap should be between five millimeters and eight millimeters, and the welding angle and the position of the pressure plate is forty-five degree angle state, and according to the actual assembly situation for grinding.
The actuator zero position is not set accurately and the full closing position of the valve is not reached. Make sure the actuator can open or close the valve fully accurately by manually opening and closing the valve fully and then adjusting the actuator zero position.
When the valve body leakage, can be repaired by the valve manufacturer to repair the valve body defects, or return to the factory to repair and replace the valve body. First of all, the existence of defects in the valve body to determine the presence of penetrating cracks, penetrating defects and more than a certain area of shrinkage is not allowed to repair, in this case, only to return to the factory to replace the valve body. For the valve body defects that can be welded, to develop a suitable welding process to determine the welding method, welding rod material, post-welding stress relief, and suitable non-destructive testing of the welding position to ensure that the repair meets the requirements.
Analysis of valve leakage causes and treatment measures can be taken to improve the bolt preload, online pressure sealing and injection of sealant treatment measures to alleviate or eliminate valve leakage. Pressure blocking should be operated by staff with solid professional foundation, and the leakage accident can be better avoided by welding and reinforcing the gap between blocking valve body end face, stuffing box and pressure plate and injecting sealant, thus bringing reference and guidance for solving similar valve leakage problems.
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