Gate valve leakage reason analysis and treatment measures

Gate Valve Leakage Causes:In the industrial field, gate valves, as a crucial fluid control equipment, are widely used in many industries such as petroleum, petrochemical, power station, long-distance pipeline and shipbuilding. Gate valves easily switch between open and closed states through the up and down movement of its opening and closing member, the gate, thus realizing the cut-off or connection of the medium in the pipeline. However, once the gate valve leaks, it may bring safety hazards to the entire pipeline system, and even threaten the lives of personnel and equipment safety. Therefore, an in-depth understanding of the structure and operation principle of the gate valve, for the correct operation of the gate valve, timely response to the leakage problem is critical.
Gate valve leakage of the six major reasons
Insufficient precision of the wedge sealing ring: the wedge sealing ring of the gate valve is divided into hard seal (metal wedge ring) and soft seal (composite graphite wedge ring). If its processing accuracy is not enough, it may lead to internal leakage of the gate valve.
Unstable working conditions: In the production process, if the pressure and ambient temperature changes, the sealing ring will be subject to greater impact, scrubbing and deformation, which in turn increases the gap between the valve body, triggering internal leakage.
Inspection quality is not up to standard: in the maintenance process, if the installation of wedge sealing ring is not thoroughly cleaned sealing surface, the residual small particles may scratch the sealing surface, resulting in leakage.
Medium corrosion: after a long time of operation, the medium may corrode the wedge sealing ring, reducing its sealing performance, thus triggering leakage.
Actuator switch is not in place: the switch of the gate valve is controlled by the actuator. If the actuator is not in place to open or close, it will lead to the gate valve can not be completely opened or closed, and then internal leakage occurs.
Valve body defects: casting valve body often exists porosity, slag, cracks and other casting defects. If these defects are not found or repaired in time, it may lead to valve leakage.
Gate valve leakage measures
Fix the valve body pressure plate and strengthen the pre-tensioning: when a small leakage inside the gate valve, should be tightened to fix the valve body pressure plate, and increase the bolt pre-tensioning force to reduce the gap between the valve body, pressure plate and sealing ring to avoid leakage.
Sealant injection: For small internal leakage, sealant can be injected into the sealing surface or packing through the grease injection hole to temporarily alleviate the leakage problem. When conditions permit, then disassemble and repair.
Welding reinforcement: For self-sealing leakage, the valve handwheel and valve frame need to be disassembled, exposing the valve body pressure plate parts, and the gap between the pressure plate and the valve body for sealing and welding reinforcement. The size of the welding gap should be moderate, so as to facilitate the subsequent reinstallation of the valve frame.
Check the zero position of the actuator: Make sure the zero position of the actuator is set accurately, so that it can accurately fully open or fully close the valve to avoid internal leakage.
Valve body patch welding or return to the factory for repair: for external leakage of the valve body, can be repaired by the valve manufacturer for patch welding or return to the factory to replace the valve body. Before welding, the valve body defects need to be judged to ensure that the welding meets the requirements.
Conclusion
Gate valve as the guardian of the industrial field, its leakage problem can not be ignored. Through in-depth analysis of the causes of leakage and take corresponding treatment measures, such as improving the bolt preload, injecting sealant, welding reinforcement, etc., we can effectively alleviate or eliminate the valve leakage problem. These measures not only provide reference and guidance for the solution of similar valve leakage problems, but also ensure the safe and stable operation of industrial systems. In the U.S. industrial environment, this knowledge and skills are important for maintaining the performance of gate valves and extending their service life.