Common faults and troubleshooting methods of valves--fisher valves

The valve may leak during use or installation, due to frequent opening and closing during use, or not installed as required and other reasons, resulting in the valve can not work normally, the following small valve will explain the cause of valve leakage and treatment methods for you

Causes of valve 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 valve is not dried and anti-corrosion treated after the water pressure is filled, resulting in internal leakage caused by corrosion of the sealing surface;

(3) The construction site protection is not in place, the two ends of the valve are not equipped with blind plates, and impurities such as rainwater and sand enter the valve seat, resulting in leakage;

(4) During installation, no grease was injected into the valve seat, causing impurities to enter the rear of the valve seat, or internal leakage caused by burns during welding;

(5) The valve is not installed in the fully open position, resulting in ball damage, during welding, if the valve is not in the full open position, the welding spatter will cause ball damage, and when the ball with welding spatter is connected to the switch, it will further cause valve seat damage, resulting in internal leakage;

(6) Welding slag and other construction residues cause scratches on the sealing surface;

(7) Leakage caused by inaccurate factory or installation time limit, if the valve stem drive sleeve or other accessories are misaligned with its assembly angle, the valve will leak.

Causes of valve leakage during operation:

(1) The common reason is that the operation manager does not maintain the valve considering the more expensive maintenance costs, or does not carry out preventive maintenance on the valve due to the lack of scientific valve management and maintenance methods, resulting in the failure of the equipment in advance;

(2) Improper operation or failure to maintain in accordance with the maintenance procedures caused by internal leakage;

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

(4) Improper pigging causes damage to the sealing surface and causes internal leakage;

(5) Long-term non-maintenance or inactivity of the valve, resulting in the locking of the valve seat and ball, and the sealing damage and internal leakage when opening and closing the valve;

(6) The valve switch is not in place to cause internal leakage, and any ball valve may cause leakage regardless of the opening and closing position, generally tilted 2°-3°

(7) Many large-diameter ball valves mostly have valve stem stop blocks, if used for a long time, due to rust and other reasons, rust, dust, paint and other debris will accumulate between the valve stem and the valve stem stop block, these sundries will cause the valve to be unable to rotate in place and cause leakage - if the valve is buried, the extended valve stem will produce and fall more rust and impurities to prevent the valve ball from rotating in place, causing valve leakage,

(8) The general actuator is also limited, if it causes corrosion for a long time, grease hardening or loose limit bolts will make the limit inaccurate, resulting in internal leakage;

(9) The valve position of the electric actuator is set forward, and it is not closed in place, resulting in internal leakage; (10) Lack of periodic maintenance and maintenance, resulting in the sealing grease drying and hardening, and the dried sealing grease accumulates behind the elastic valve seat, hindering the movement of the valve seat and causing the seal to fail.

Procedures for handling valve leakage

(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) Inject a certain amount of grease first to see if the leakage can be stopped, then the injection speed must be slow, and at the same time observe the change of the pressure gauge pointer at the outlet of the grease injection gun to determine the internal leakage of the valve.

(3) If the leakage cannot be stopped, it may be caused by the hardening of the sealing grease injected in the early stage or the damage of the sealing surface. It is recommended to inject valve cleaning solution at this time to clean the sealing surface and seat of the valve. Generally, soak for half an hour less, if necessary, you can soak for a few hours or even a few days, and then do the next step after the solidified material is all dissolved. During this process, it is good to open and close the movable valve several times.

(4) Re-inject grease, open and close the valve intermittently, and discharge impurities out of the rear cavity of the valve seat and the sealing surface.

(5) Check in the full shutdown position, if there is still leakage, the reinforced sealing grease should be injected, and the valve cavity should be opened at the same time for venting, which can produce a large pressure difference and help sealing.

(6) If there is still internal leakage, the valve should be repaired or replaced.

Common faults and troubleshooting methods of valves--fisher valves

Common faults and troubleshooting methods of valves--fisher valves

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