Here are the common faults and solutions in the use of the ball valve.
When we install or use the
ball valve, internal water leakage of the ball valve is possible. Due to frequent use of the switch, or not satisfying the requirements of the installation and other reasons, it will result in the ball valve can not work normally. We will explain the causes of ball valve internal leakage and treatment methods as follows.
Reasons for valve internal leakage during the construction period
(1) Improper transportation and hoisting cause overall damage to the
valve, resulting in internal leakage of the valve.
(2)When leaving the factory, the hydraulic pressure is not dried and anticorrosive treatment of the valve, which results in corrosion of the sealing surface to form internal leakage.
(3) Construction site protection is not in place. The two ends of the valve are not installed with blind plates, rain, sand and other impurities into the seat, causing leakage.
(4) When installing, no grease is injected into the valve seat, causing impurities to enter the back of the valve seat, or internal leakage caused by welding burns.
(5) The valve is not installed in the fully open position, causing damage to the ball. In the process of welding, if the valve is not fully open, the welding splash will cause damage to the ball. When the ball with the welding splash in the switch will further cause damage to the seat, resulting in internal leakage.
(6)The welding slag and other construction remnants caused by sealing surface scratches.
(7) Factory or installation time is not accurate resulting in leakage. If the stem drive sleeve or other accessories with the assembly angle dislocate, the valve will leak.
Reasons for internal leakage of the valve during operation
(1) The most common reason is that the operation manager does not maintain the valve considering the more expensive maintenance costs. The lack of scientific valve management and maintenance methods does not carry out preventive maintenance on the valve, resulting in the failure of equipment in advance.
(2) Internal leakage is caused by improper operation or failure to maintain according to maintenance procedures.
(3) In normal operation, construction debris scratches the sealing surface, which causes internal leakage.
(4) Improper pigging causes damage to the sealing surface resulting in internal leakage.
(5) Long-term maintenance or inactive valve result in valve seat and ball locked. When the valve is switched on and off to form internal leakage, resulting in sealing damage.
(6) The valve switch is not in place resulting in internal leakage. Whether any ball valve opens or close, generally tilting 2° to 3° may cause leakage.
(7) Many large-diameter ball valves have the stem stop block. If used for a long time, it will accumulate rust, dust, paint and other sundries due to corrosion and other reasons between the stem. These sundries will cause the valve can not rotate in place and cause leakage. If the valve is buried, lengthening the valve stem will produce and drop more rust and impurities to prevent the valve ball from rotating in place. Finally, it will cause valve leakage.
(8) The general actuator is also limited. If long-term corrosion, grease hardening, or limited bolt loosening will make the limit inaccurate, resulting in internal leakage.
(9) The valve position of the electric actuator is set to the front, which causes internal leakage.
Procedures for handling internal leakage of the ball valve
(1) Check the limit of the valve to see whether the internal leakage of the valve can be solved by adjusting the limit.
(2) Inject a certain amount of grease to see whether it can stop leakage, then the injection speed must be slow. Observe the change of the grease gun outlet pressure gauge pointer to determine the internal leakage of the valve.
(3) If the leakage can not be stopped, it may be the early injection of sealing grease hardening or sealing surface damage caused by internal leakage. It is recommended to inject a valve-cleaning solution at this time to clean the sealing surface of the valve and the valve seat. Generally, soak at least half an hour. If necessary, it can soak for a few hours or even a few days until the cured substance is all dissolved before doing the next step. It is best to open and close the movable valve several times during this process.
(4) Re-inject grease, intermittently open and close the valve, and discharge the impurities from the chamber and sealing surface of the seat.
(5) Check at the full close position, if there is still leakage, it should be injected into the strengthening seal fat. At the same time, open the valve cavity for cavitation, which can produce a large pressure difference, which can help to seal. Under normal circumstances, injecting the strengthening seal fat leakage can be eliminated.
If there is still internal leakage, it is necessary to repair or replace the valve.
