When installing a control valve, please observe the following:
To change the mounting direction of the actuator, proceed as follows: Apply a pneumatic pressure of approximately 60 kPa (0.6 kgf / cm2) to the diaphragm so that the valve lift is set at a mid-position of its range. Loosen the yoke clamp nut with a wrench Swivel the overall actuator to the correct position, and then securely tighten the yoke clamp nut with a wrench. Release the pneumatic pressure applied to the diaphragm. In case of a control valve that has a bellows seal, how- ever, disconnect the actuator stem from the valve stem and then loosen the yoke clamp nut and swivel the actuator section.
Before starting operating of the control valve, check & confirm the following to ensure all conditions are correct and secure.
Periodically inspect and perform maintenance service to the control valve for the following:
Generally the diaphragm control valve does not require adjustment. However, when it is disassembled and reassembled for overhaul or parts replacement, adjustment should be made as described below:
Connect the air tubing to the diaphragm chamber while the stem connector is disen- gaged to supply compressed air to the chamber.
Push down the valve stem and make the valve plug touch on the valve seat.
Next, apply air pressure up to 5~10% (min. 1%) of the rated lift (check name plate for lift rate) from the reference position of no air in the chamber then fix the pressure at this position. The index on the scale should be set at SHUT at this point.
Connect the actuator stem to the valve stem with the stem connector.
Increase air pressure to the diaphragm chamber and verify the valve lift is more than the rated lift range and the valve seat and plug touch each other. Make sure that this contact takes place while in the SHUT position.
Connect the air tubing to the diaphragm chamber while the stem connector is disen- gaged to supply compressed air to the chamber.
Push down the valve stem and make the valve plug touch on the valve seat. Apply air pressure to the diaphragm chamber until the actuator stem stops.
Next, reduce the pressure in the diaphragm chamber until the lift is 5~10% above the rated lift range (min. 1 mm) then fix the pressure at this position. The index on the scale should be set at SHUT at this point.
Connect the actuator stem to the valve stem with stem connector at this position. Reduce the air pressure to the diaphragm chamber and verify if the valve lift is more than the rated lift range (min. 1 mm) and the valve seat and plug touch each other.
Make sure that this contact takes place while in the SHUT position.
This adjustment must be made after lift adjustment.
Connect air tubing to the diaphragm chamber to supply compressed air.
Apply low end of the pressure as specified on the name plate to the diaphragm chamber, and adjust by tightening the spring to ensure that the index on the scale starts to move below OPEN; and when the higher end pressure is applied to the diaphragm chamber, the index shows SHUT.
Tightening of spring adjuster can be made easily with no air pressure to the diaphragm chamber.
Connect air tubing to the diaphragm chamber to supply compressed air
Apply low end of the pressure as specified on the name plate to the diaphragm chamber, and adjust by tightening the spring to ensure that the index on scale starts to move beyond SHUT, and when higher end pressure is applied to the diaphragm chamber, the index shows OPEN.
Tightening of spring adjuster can be made easily with no air pressure to the diaphragm chamber.
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