Causes of ball valve internal leakage, causes of valve internal leakage during construction:

(1) improper transportation and hoisting cause the overall damage of the valve, resulting in valve leakage;

(2) When leaving the factory, the water pressure is not dried and anticorrosive treatment of the valve, resulting in corrosion of the sealing surface and internal leakage;

(3) the construction site protection is not in place, the valve ends are not equipped with blind plates, rain water, sand and other impurities into the valve seat, resulting in leakage;

(4) when installing, there is no grease injected into the valve seat, resulting in impurities into the back of the valve seat, or welding burn caused by internal leakage;

(5) The valve is not installed in the full open position, causing damage to the ball, in the 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 in the switch will further cause damage to the valve seat, resulting in internal leakage;

(6) welding slag and other construction relics caused by the sealing surface scratch;

The factory or installation time limit is not accurate caused by leakage, if the stem drive sleeve or other accessories and the assembly Angle dislocation, 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 considering the relatively expensive maintenance cost, or does not carry out preventive maintenance on the valve due to the lack of scientific valve management and maintenance methods, resulting in equipment failure in advance;

(2) Internal leakage caused by improper operation or failure to maintain in accordance with maintenance procedures;

(3) During normal operation, construction relics scratch the sealing surface, resulting in internal leakage;

(4) improper pigging caused damage to the sealing surface resulting in internal leakage;

(5) long-term maintenance or inactivity of the valve, resulting in the valve seat and the ball locked, when opening and closing the valve caused sealing damage to form internal leakage;

(6) The valve switch is not in place to cause internal leakage, any ball valve whether open or closed, generally tilt 2° ~ 3° may cause leakage;

(7) many large diameter ball valve mostly stem stop block, if the use of a long time, due to rust and other reasons in the stem and stem stop block will accumulate rust, dust, paint and other sundries, these sundries will cause the valve can not be rotated in place and cause leakage — if the valve is buried, Lengthening the stem will create and drop more rust and impurities that prevent the valve ball from rotating in place and cause valve leakage.

(8) The general actuator is also limited, if the long-term cause corrosion, grease hardening or limit bolt loosening will make the limit is not accurate, resulting in leakage;

(9) The valve position of the electric actuator is set in the front, and it is not in place to cause internal leakage; Attendees lack of periodic maintenance and maintenance, resulting in dry and hard sealing fat, dry sealing fat accumulation in the elastic valve seat, hinder the movement of the valve seat, resulting in sealing failure.

Ball valve leakage treatment procedures 

(1) First check the limit of the valve to see if the internal leakage of the valve can be solved by adjusting the limit.

(2) First inject a certain amount of grease to see if it can stop leakage, then the injection speed must be slow, and observe the change of the pressure gauge pointer at the grease gun outlet to determine the leakage of the valve.

(3) if the leakage can not be stopped, it is possible that the early injection of sealing fat hardened or sealing surface damage caused by leakage. It is recommended that the valve cleaning fluid be injected at this time to clean the sealing surface of the valve and the valve seat. Generally soaked for at least half an hour, if necessary, can soak for a few hours or even a few days, to be cured after all dissolved and then do the next step of treatment. It is desirable to open and close the movable valve several times during this process.

(4) re-inject the grease, intermittently open and close the valve, and discharge the impurities from the seat back chamber and sealing surface.

(5) check in the full closed position, if there is still leakage, should be injected to strengthen the level of sealing grease, while opening the valve chamber for venting, which can produce a large pressure difference, help seal, under normal circumstances, through the injection of strengthening the level of sealing grease leakage can be eliminated.

If there are still leaks, repair or replace the valve.