The causes and solutions of internal leakage in forged steel ball valves are as follows:

I. Causes of Internal leakage

1. Executive agency issues:

The zero position setting of the actuator is inaccurate and the valve is not completely closed.

The torque force of the actuator is insufficient to overcome the driving force of the medium, resulting in the valve not closing properly.

The limit error of the actuator causes the valve to fail to close properly.

2. Manufacturing quality issues:

During the valve manufacturing process, the control of material, processing technology and assembly technology was not strict, resulting in unqualified grinding of the sealing surface, with defects such as pitting and sand holes.

The valve was not subjected to drying treatment and anti-corrosion treatment when leaving the factory, resulting in rusting of the sealing surface.

3. Control part issues:

Traditional control methods (such as valve limit switches and over-torque switches) are affected by environmental temperature, pressure and humidity, resulting in inaccurate valve positioning.

The action position of the limit switch is relatively fixed. During operation, the erosion and wear of the medium on the valve result in the valve not closing tightly.

4. Debugging issues:

Improper stroke adjustment during debugging led to the valve not closing tightly or not opening electrically.

Internal leakage caused unconsciously during the debugging process, such as excessive stroke adjustment leading to the over-torque switch protection action.

5. Incorrect selection:

Improper valve selection led to cavitation corrosion and caused internal leakage.

6. Medium scouring and aging:

After long-term operation of the valve, the medium erosion causes wear on the valve core and valve seat, as well as aging of the internal components.

The aging of the sealing ring leads to poor sealing.

7. Construction legacy issues:

Unreasonable transportation and hoisting caused overall damage to the valve.

The construction site was not properly protected, and impurities such as rainwater and sand entered the valve seat.

During installation, grease was not injected into the valve seat, or internal leakage was caused by burns during electric welding.

Welding slag and other construction residues cause scratches on the sealing surface.

8. Operation and maintenance issues:

The operation is unreasonable or the maintenance is not carried out in accordance with the maintenance procedures.

Long-term failure to maintain or move the valve can cause the valve seat and the ball to seize up.

If the valve is not opened or closed properly, any ball valve tilting by 2° to 3° may cause leakage.

Long-term rusting of the actuator limit, hardening of the lubricating grease or loosening of the limit bolts lead to inaccurate limit.

Ii. Solutions

1. Adjust the actuator:

Manually close the valve and confirm that it is completely closed. Then, gently twist it with force and adjust the limit.

Replace the actuator with a large thrust or the balance valve core to reduce the unbalanced force of the medium.

2. Reprocess the sealing surface:

For valves with unqualified grinding or defects on the sealing surface, reprocess the sealing surface.

3. Optimization Control Section:

Readjust the upper limit or limit position to ensure the valve is accurately positioned.

Consider adopting more advanced control methods to reduce the influence of environmental factors on valve control.

4. Improve the debugging method

When debugging the electric control valve, manually shake the electric control valve to the bottom, then swing it in the open direction, set the lower limit switch position of the electric door, then open the electric ball valve to the fully open position and set the upper limit switch position.

Regularly readjust the limit switches to adapt to the erosion and wear of the valve by the medium.

5. Strengthen maintenance and upkeep

Regularly inject grease and clean the valve seat flow channels to prevent the accumulation of impurities.

Regularly check the opening and closing status and sealing performance of the valve, and promptly detect and handle internal leakage problems.

6. Reasonable selection:

Select the electric control valve reasonably according to the system process flow to avoid problems such as cavitation corrosion caused by incorrect selection.