The ball valve may leak internally during use or installation. Due to frequent switching during use, or failure to install according to requirements and other reasons, the ball valve cannot work properly. The following will explain the reasons for the internal leakage of the ball valve and how to deal with it.
Causes of internal leakage of ball valves
Causes of internal leakage of valves during construction
①Improper transportation and hoisting cause overall damage to the valve, resulting in internal leakage of the valve;
②When leaving the factory, the valve is not dried and treated with anti-corrosion after water pressure is applied, resulting in rust on the sealing surface and internal leakage;
③The construction site is not properly protected, and blind plates are not installed at both ends of the valve, causing rainwater, sand and other impurities to enter the valve seat, causing leakage;
④During installation, grease is not injected into the valve seat, causing impurities to enter the back of the valve seat, or burning during welding causes internal leakage;
⑤The valve is not installed in the full open position, causing damage to the ball. During welding, if the valve is not in the full open position, welding spatter will cause damage to the ball. When the ball with welding spatter is switched, it will further cause damage to the valve seat, resulting in internal leakage;
⑥Welding slag and other construction residues cause scratches on the sealing surface;
⑦Inaccurate limit at the time of leaving the factory or installation causes leakage. If the valve stem drive sleeve or other accessories are misaligned with the assembly angle, the valve will leak.
Causes of valve internal leakage during operation
① The most common reason is that the operation manager does not maintain the valve due to the relatively expensive maintenance costs, or lacks scientific valve management and maintenance methods to prevent valve maintenance, causing equipment failure in advance;
② Improper operation or failure to perform maintenance according to the maintenance procedures causes internal leakage;
③ During normal operation, construction residues scratch the sealing surface, causing internal leakage;
④ Improper cleaning causes sealing surface damage and causes internal leakage;
⑤ Long-term non-maintenance or inactivity of the valve causes the valve seat and the ball to lock, causing sealing damage and internal leakage when the valve is opened and closed;
⑥ Internal leakage caused by inadequate valve opening and closing. Any ball valve, regardless of the open or closed position, generally tilts 2° to 3° and may cause leakage;
⑦ Many large Most ball valves of different diameters have stem stops. If they are used for a long time, rust, dust, paint and other debris will accumulate between the stem and the stem stop due to corrosion and other reasons. These debris will cause the valve to be unable to rotate into place and cause leakage. If the valve is buried, the extended stem will produce and drop more rust and impurities to prevent the valve ball from rotating into place, causing valve leakage;
⑧General actuators also have limits. If they are corroded for a long time, the grease will harden or the limit bolts will loosen, which will make the limit inaccurate and cause internal leakage;
⑨The valve position of the electric actuator is set forward and is not closed in place, causing internal leakage; ⑩Lack of periodic maintenance and care causes the sealing grease to dry and harden. The dried sealing grease accumulates behind the elastic valve seat, hindering the movement of the valve seat and causing sealing failure.
Processing procedures for ball valve internal leakage
①First check the limit of the valve to see if the internal leakage of the valve can be solved by adjusting the limit.
②First, inject a certain amount of grease to see if it can stop the leakage. At this time, the injection speed must be slow, and at the same time, observe the changes in the pointer of the pressure gauge at the outlet of the grease gun to determine the internal leakage of the valve.
③If the leakage cannot be stopped, it may be that the sealing grease injected earlier has hardened or the sealing surface is damaged, causing internal leakage. It is recommended to inject valve cleaning fluid at this time to clean the sealing surface and valve seat of the valve. Generally, soak for at least half an hour. If necessary, soak for several hours or even several days. Wait until the solidified material is completely dissolved before proceeding to the next step. It is best to open and close the movable valve several times during this process.
④Re-inject grease, open and close the valve intermittently, and discharge impurities from the back cavity of the valve seat and the sealing surface.
⑤Check in the fully closed position. If there is still leakage, inject enhanced sealing grease and open the valve cavity for venting. This can generate a large pressure difference and help seal. Under normal circumstances, internal leakage can be eliminated by injecting enhanced sealing grease.
⑥If there is still internal leakage, the valve must be repaired or replaced.