Valtek MK1 Rebuild

Valtek MK1 Rebuild

PSA Valve Rebuild in pictures3” valve with Kalrez packing, soft seat and PTFE seat and bonnet gaskets

Valtek MK1 Control Valve

• Valtek valve mounted in vise for rebuild. Spray all fasteners and mating pieces with Kroil for ease of removal.

Preparing for Rebuild

• Center punch valve components for removal so that they go back the way they were taken apart.

Removing stored energy

• The actuator spring’s stored energy must be removed. This is accomplished by removing the bolt on top of the actuator.

Actuator Bolting

• Begin disassembly of actuator from valve body by removing fasteners from packing follower and actuator clamp.

Removing the Actuator Clamp

• A punch or wedge may be required to knock loose the actuator clamp.

Actuator Tubing Removal

• Disassemble tubing from actuator and positioner and set aside.

Separating plug from Actuator on a Fail Closed Valtek Valve

• Apply a little air to the bottom of the actuator to lift the plug off the seat.

Unthreading Plug/Stem

• Loosen the stem clamp and locknut and unthread the valve plug/stem while lifted off the seat. This prevents damage to the seating surfaces of the plug and seat.

Removing Stem Locknut

• The locknut on the stem must be removed before the packing follower can be removed. Apply enough air to actuator to remove locknut being careful nut to place fingers in a position to pinch.

Actuator removal

• After removing the packing follower, the actuator is free to be removed.

Actuator

• Place actuator in another vise or set aside to work on after valve body rebuild is complete. Place all removed components on workbench for clean up and ease of reassembly.

Loosening Bonnet Nuts

• Using an impact gun or combination wrench, loosen nuts on bonnet for removal.

Removing Bonnet Assembly

• With bonnet nuts removed, lift off the bonnet retainer collar and set aside. Pull bonnet assembly from valve body and set on workbench. Seat retainer can now be removed.

Seat Retainer

• The word “UP” is casted into the seat retainer. Make sure that during reassembly the retainer is in the correct position.

3 Piece Soft Seat, Seat Ring

• Remove seat ring from valve body. This may require the use of a bearing puller inserted under the seat to assist in its removal.

3 Piece Seat Ring

Valve Bonnet

• Bead blast the valve bonnet being careful to not bead blast the packing cavity. Apply some paint to the exterior of the valve bonnet and clean the packing area.

Valve Components for Rebuild

• Laying out all restored and new valve components speeds the rebuild process and provides an orderly rebuild along with a neat work area.

Kalrez Packing Rings

• Apply a little bit of Krytox to the Kalrez chevron packing rings. Use nitrile gloves when handling Krytox.

Stem Cleaning

• Clean off stem residue and polish stem with diamond polish with stem in lathe using a cloth.

Body Reassembly

Seat Ring, Seat Retainer, Plug/Stem and Bonnet reinstalled. Don’t forget the Bonnet Gasket!

Valve Repack

• Repack valve, install bonnet flange and loosely install bonnet nuts. Do not tighten bonnet nuts at this time.

Actuator Repair

• With the actuator stored energy removed by removing the bolt on top of the actuator, remove the lock ring at the base of the actuator.

Actuator Top Removed

• Actuator without the actuator top in place. Note the position of the spring, spring retainer and piston spacer.

Actuator Top

• Before and after pictures of actuator top. Check inside finish with finger tips to make sure there are no obstructions that may damage new piston o-ring. Replace with a new top if there are deep wear points.

Actuator Base and Yoke

• Note O-Ring residue on actuator base and condition of actuator stem o-ring and guide bushings.

Actuator Reassembly

• Replace all O-Rings and lube with o-ring lubricant. Reassemble actuator components.

Finishing Actuator Rebuild

• Reinstall actuator lock ring at base of actuator. Lube actuator bolt and reinstall bolt being careful to line up spring retainer hole on the spring retainer plate.

Actuator Reinstalled

• Reinstall actuator on valve. Placing actuator over stem, place packing follower over stem, thread on stem locknut. Orient actuator shaft with slits toward yokes so stem clamp will work properly.

Complete

• Calibrate positoner, and feedback sensor. Check stroke during calibration.