The pneumatic emergency shut-off valve leaks and does not close properly – how to deal with it?
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In manual mode, it can be closed tightly; in automatic mode, it stops closing 1-2 notches short. Since the pipeline carries natural gas, internal leaks are not allowed. I would also like to ask the experts how to adjust and what the function of the four screws shown in the diagram is. Thank you!
The two screws on the valve body are used for adjusting the limits, preventing the switch from going beyond its limits and thus avoiding internal leakage caused by excessive movement of the ball valve. The two screws on the cylinder are likely used to connect to the five-way control valve. The issue you mentioned of poor sealing is likely due to insufficient cylinder power, as well as inadequate compressed air pressure. There should be no problem with the five-way valve
If there are no issues with the wind pressure or solenoid valves, there is an adjustment screw on the cylinder side, usually accompanied by a locknut, which is used to adjust or limit the rotation angle of the shaft. An adjustment within 0-5 degrees is possible; it’s a simple fix that will resolve the problem easily.
The actuator’s stroke is insufficient; adjust it
The two screws on the valve body are used for adjusting the limits, preventing the switch from going beyond its specified range; by making slight adjustments to the closing position, the performance might improve. Carefully observe the position of the valve stem to determine whether it is actually in place
Since it can be shut off manually but not automatically, the most likely reason is insufficient pressure in the gas supply; try adjusting the pressure regulator to set the gas supply pressure at its maximum level.