When using the valve, there are frequently some annoying issues, including the valve not being closed all the way. What should I do? The control valve has a variety of internal leakage sources because of its type of valve’s rather complex structure. Today, we’ll discuss the seven different forms of internal control valve leaks and the analysis and fixes for each.

1. The valve has not closed to its fullest extent and the actuator’s zero position setting is inaccurate.

Solution:

1) Manually close the valve (certain that it is completely closed);

2) Reopen the valve manually, provided that a little force cannot be applied to turn it;

3) Turn the valve half a turn in the opposite direction;

4) Next, alter the upper limit.

2. The actuator’s thrust is insufficient.

The actuator’s thrust is insufficient because the valve is of the push-down closing variety. When there is no pressure, it is simple to get to the fully closed position, but when there is pressure, the upward surge of the liquid cannot be countered, making it impossible to close completely.

Solution: replace the high-thrust actuator, or change to a balanced spool to reduce the unbalanced force of the medium

3. Internal leakage brought on by poor electric control valve construction quality

Because valve manufacturers do not rigorously control the valve material, processing technology, assembly technology, etc. during the production process, the sealing surface is not ground to a high standard and flaws like pitting and trachoma are not completely removed, leading to internal leakage of the electric control valve.

Solution: Reprocess the sealing surface

4. The electric control valve’s control portion has an impact on the valve’s internal leakage.

Mechanical control methods, including valve limit switches and over torque switches, are the traditional way to operate an electric control valve. The valve location is imprecise, the spring is worn out, and the coefficient of thermal expansion is uneven because these control elements are impacted by the surrounding temperature, pressure, and humidity. and other external circumstances, which are to blame for the electric control valve’s internal leak.

Solution: readjust the limit.

5. Internal leakage brought on by issues with the electric control valve’s troubleshooting

It is typical for electric control valves to fail to open after being manually closed, which is caused by the processing and assembly processes. The action position of the upper and lower limit switches can be used to adjust the stroke of the electric control valve. If the stroke is adjusted smaller, the electric control valve will not close tightly or open; if the stroke is adjusted larger, it will cause excessive the torque switch’s protective mechanism;

If the over-torque switch’s action value is increased, there will be an accident that could harm the valve or the reduction transmission mechanism, or even burn the motor. Typically, after the electric control valve has been debugged, the lower limit switch position of the electric door is set by manually shaking the electric control valve to the bottom, followed by shaking it in the opening direction, and the upper limit is set by manually shaking the electric control valve to the fully open position.

Thus, the electric control valve won’t be prevented from opening after being tightly closed by hand, allowing the electric door to open and close freely, but it will essentially result in internal leaking of the electric door. Even if the electric control valve is perfectly set, since the limit switch’s action position is mostly fixed, the medium it controls will continuously wash and wear the valve while it is in use, which will also result in internal leakage from the valve’s slack closure.

Solution: readjust the limit.

6. Cavitation The internal leaking of the electric control valve is caused by corrosion of the valve brought on by the incorrect type selection.

Cavitation and pressure differential are connected. Cavitation will happen if the actual pressure difference P of the valve is higher than the critical pressure difference Pc for cavitation. A significant amount of energy is produced during the cavitation process when the bubble bursts, which has an impact on the valve seat and the valve core. The general valve operates in cavitation conditions for three months or less, meaning the valve suffers from severe cavitation corrosion, resulting in leakage of the valve seat up to 30% of the rated flow. Throttling components have a significant destructive effect. This damage cannot be fixed.

Therefore, the specific technical requirements for electric valves vary depending on their intended use. It is crucial to select electric control valves intelligently in accordance with the system procedure.

Solution: To improve the process, choose a multi-stage step-down or sleeve regulating valve.

7. Internal leakage resulting from medium deterioration and aging of the electric control valve

After the electric control valve has been adjusted, after a certain amount of operation, the electric control valve will be closed because the stroke is too large as a result of the valve cavitating, the medium eroding, the valve core and seat wearing out, and the aging of internal components. The increase in the electric control valve’s leakage is a result of the laxness phenomena. The electric control valve’s internal leak will progressively get worse over time.

Solution: readjust the actuator and perform regular maintenance and calibration.