Assembly Instructions for KX Valve Rings

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.


  1. Open the valve fully
  2. Uncrew the bonnet fastening nuts and remove the disk springs
  3. Turn the handwheel clockwise (the bonnet should rise up and out of the housing)
  4. Turn the bonnet until the bonnet flange rests against the stud-bolt face
  5. Turn the handwheel anti-clockwise until the piston is completely free of the top valve ring
  6. Remove the bonnet with the handwheel and piston assembly, being careful not to damage the polished piston skirt

Changing the valve ring

  1. Remove the thrust piece and top valve ring using the ring extractor hook (where fitted)
  2. Remove the lantern from the housing using the lantern bush extractor hook
  3. Carefully clean the valve ring seat and housing bore
  4. Remove the bonnet valve rings from the neck of the bonnet (where fitted)
  5. Mount the top valve ring with the KX mounting tool
  6. Replace the newly cleaned lantern bush, ensuring that no teeth are on the valve outlet side
  7. Insert the thrust piece (where applicable)
  8. Insert the bonnet valve ring into the housing bore using the KX mounting tool (where aplicable)

Assembly & commisioning

  1. Screw the spindle & piston assembly into the bonnet as far as it will go by turning the handwheel anti-clockwise
  2. Position the bonnet on the valve housing and tighten the nuts a few threads
  3. Close the valve completely and then open it again, the bonnet should withdraw into the housing
  4. Unscrew the hexagon nuts again, mount the disk springs and proceed to tighten the hexagon nuts
  5. Close the valve fully by turning the handwheel clockwise
  6. Carefully tighten the hexagon nuts, in an X pattern, to the specified torque
    Valve Size
    Torque Nm
    DN 10
    DN 15
    DN 20
    DN 25
    DN 32
    DN 40
    DN 50
    DN 65
    DN 80
    DN 100
    DN 125
    DN 150
    DN 200