Time：2021-03-17 13:17 Browse：
Ball valve common faults and troubleshooting methods ball valve may appear during the use or installation of internal leakage, due to frequent use of the switch, or not installed as required and other reasons, resulting in the ball valve can not work properly.
The causes of leakage in the ball valve are mainly divided into two categories:
Causes of valve leakage during construction period:
①Improper transportation and lifting cause the overall damage of the valve resulting in valve leakage;
②When leaving the factory, the valve is not dried or corroded by water pressure, resulting in inner leakage.
③The construction site protection is not in place, the valve ends are not installed blind plate, rain, sand and other impurities into the valve seat, resulting in leakage;
④During installation, grease is not injected into the seat, causing impurities to enter the back of the seat or internal leakage caused by burns during welding;
⑤The valve is not installed in the full open position, causing ball damage. During welding, if the valve is not in the full open position, ball damage will be caused by welding spatter.
⑥The sealing surface is scratched by welding slag and other construction residues;
⑦Leakage is caused by inaccurate delivery or installation time. If the valve stem drive sleeve or other accessories are misaligned with the assembly Angle, the valve will leak.
Causes of internal leakage during operation:
①The most common reason is that the operation manager does not maintain the valve in consideration of relatively expensive maintenance costs, or the lack of scientific valve management and maintenance methods do not carry out preventive maintenance on the valve, resulting in equipment failure in advance;
②Improper operation or failure to follow the maintenance procedures resulting in internal leakage;
③In normal operation, construction residue scratches the sealing surface, causing internal leakage;
④Improper pigging causes damage to the sealing surface and causes internal leakage;
⑤Do not maintain or do not move the valve for a long time, resulting in the valve seat and ball locked, in the opening and closing of the valve caused by sealing damage and internal leakage;
⑥The valve switch is not in place to cause internal leakage, any ball valve regardless of open, close position, general tilt 2° ~ 3° may cause leakage;
⑦Many large diameter ball valves have stem mostly stop block, if you use a long time, due to reasons such as corrosion in the stem and stem between stop blocks will accumulate rust, dirt, paint and other sundry, these stuff will leak valve cannot be rotated due, if the valve is buried, elongated stem yield and falling more rust and impurities hinder valve ball spinning in place, cause the valve leakage;
⑧General actuator is also limited, if long-term cause rust, grease hardening or limit bolt loose will make the limit is not accurate, resulting in internal leakage;
⑨The valve position of the electric actuator is set forward, which causes internal leakage if it is not in place.
⑩The lack of periodic maintenance and maintenance causes the seal grease to become dry and hard. The dried seal grease accumulates in the elastic seat, impedes the seat movement and causes the seal failure.
Handling procedures for leakage in the ball valve:
①First check the valve limit to see if internal leakage can be resolved by adjusting the limit.
②First inject a certain amount of grease to see if it can stop the leakage, then the injection speed must be slow, at the same time observe the grease gun outlet pressure gauge pointer changes to determine the valve leakage situation.
③If leakage cannot be checked, it may be caused by early injection of seal grease hardening or seal surface damage. It is recommended that valve cleaning fluid be injected to clean the valve sealing surface and seat. Generally at least half an hour soak, if necessary can soak a few hours or even a few days, to be cured after all the dissolution of the next step. It is best to switch the valve several times during this process.
④Re-inject grease to open and close the valve intermittently to remove impurities from the seat cavity and sealing surface.
⑤If there is still leakage in the inspection at the full close position, the reinforced seal grease should be injected and the valve chamber should be opened for empting, which can produce a large pressure difference and help seal. In general, the leakage in the reinforced seal grease can be eliminated by injecting.
⑥If there is still a leak, the valve should be repaired or replaced.