Preparing to replace a valve ring
- The valve can remain in the pipelne while the valve ring is being replaced, however, the line must be de-pressurised and emptied beforehand.
- The valve rings can be replaced using simple dismantling and assembly tools.
Dismantling
- Open the valve fully
- Uncrew the bonnet fastening nuts and remove the disk springs
- Turn the handwheel clockwise (the bonnet should rise up and out of the housing)
- Turn the bonnet until the bonnet flange rests against the stud-bolt face
- Turn the handwheel anti-clockwise until the piston is completely free of the top valve ring
- Remove the bonnet with the handwheel and piston assembly, being careful not to damage the polished piston skirt
Changing the valve ring
- Remove the thrust piece and top valve ring using the ring extractor hook (where fitted)
- Remove the lantern from the housing using the lantern bush extractor hook
- Carefully clean the valve ring seat and housing bore
- Remove the bonnet valve rings from the neck of the bonnet (where fitted)
- Mount the top valve ring with the KX mounting tool
- Replace the newly cleaned lantern bush, ensuring that no teeth are on the valve outlet side
- Insert the thrust piece (where applicable)
- Insert the bonnet valve ring into the housing bore using the KX mounting tool (where aplicable)
Assembly & commisioning
- Screw the spindle & piston assembly into the bonnet as far as it will go by turning the handwheel anti-clockwise
- Position the bonnet on the valve housing and tighten the nuts a few threads
- Close the valve completely and then open it again, the bonnet should withdraw into the housing
- Unscrew the hexagon nuts again, mount the disk springs and proceed to tighten the hexagon nuts
- Close the valve fully by turning the handwheel clockwise
- Carefully tighten the hexagon nuts, in an X pattern, to the specified torque
Valve SizeTorque NmDN 105DN 155DN 205DN 256DN 329DN 4013.5DN 5017DN 6530DN 8025DN 10020DN 12545DN 15040DN 20075
