Common faults of ball valves and troubleshooting methods Ball valves may have internal leakage during use or installation. Due to frequent switching during use, or failure to install as required, the ball valve cannot work normally.
The reasons for the internal leakage of the ball valve are mainly divided into two categories: the reasons for the internal leakage of the valve during the construction period:
① Improper transportation and hoisting cause overall damage to the valve and cause internal leakage of the valve;
②When leaving the factory, the valve was not dried and anti-corrosive after the water pressure was applied, causing the sealing surface to rust and form internal leakage;
③The protection of the construction site is not in place, there is no blind plate installed at both ends of the valve, and impurities such as rainwater and sand enter the valve seat, causing leakage;
④During installation, no grease was injected into the valve seat, causing impurities to enter the back of the valve seat, or internal leakage during welding*;
⑤The valve is not installed in the fully open position, causing damage to the ball. During welding, if the valve is not in the fully open position, welding spatter will cause damage to the ball. When the ball with welding spatter is switched on and off, it will further cause damage to the valve seat. , Which leads to internal leakage;
⑥Scratches on the sealing surface caused by welding slag and other construction objects;
⑦The inaccurate limit at the time of delivery or installation causes leakage. If the valve stem drive sleeve or other accessories are misaligned with the assembly angle, the valve will leak.
Reasons for valve internal leakage during operation:
①*The common reason is that the operation manager does not maintain the valve in consideration of the relatively expensive maintenance cost, or the lack of scientific valve management and maintenance methods does not perform preventive maintenance on the valve, which causes the equipment to malfunction in advance;
②Improper operation or failure to follow the maintenance procedures to maintain internal leakage;
③During normal operation, the construction material scratches the sealing surface, causing internal leakage;
④ Improper pigging causes internal leakage due to damage to the sealing surface;
⑤ If the valve is not maintained or moved for a long time, the valve seat and the ball will lock up, and the seal will be damaged when the valve is opened and closed, and internal leakage will be formed;
⑥The valve switch is not in place to cause internal leakage. Any ball valve, regardless of the open or closed position, generally tilts 2°~3° to cause leakage;
⑦Many large-caliber ball valves mostly have stem stoppers. If they are used for a long time, rust, dust, paint and other debris will accumulate between the stem and stem stopper due to rust and other reasons. These debris will cause the valve Failure to rotate in place and cause leakage-if the valve is buried, extending the stem will produce and drop more rust and impurities to prevent the ball from rotating in place, causing the valve to leak;
⑧The general actuator is also limited. If it causes corrosion for a long time, hardening of the grease or loosening of the limit bolts, the limit will be inaccurate and cause internal leakage;
⑨The valve position of the electric actuator is set forward, and it is not closed in place to cause internal leakage;
⑩Lack of periodic maintenance and maintenance, causing the sealing grease to dry and harden, and the dried sealing grease accumulates behind the elastic valve seat, hindering The valve seat moves, causing the seal to fail.
Post time: Mar-12-2021