Baker Hughes Cage Guided Globe Valve 21009 Series

Packing box maintenance is one of the principle action items of routine servicing. Tightness of the packing is maintained by packing compression. Compression is achieved by evenly tightening the packing flange nuts (3) against the packing flange (4)

Care must be taken not to over tighten as this could prevent smooth operation of the valve. If all compression is used up and the valve leaks, then new packing is required. Braided PTFE with Carbon or aramid Core (Standard)

Note: The Braided PTFE/Carbon or Aramid packing rings have a skive cut allowing packing replacement without discon-necting the plug stem from the actuator connector or actuator stem.

A. Loosen and remove packing flange nuts (3).

B. Lift the packing flange (4) and packing follower (5) up the valve stem.

Note: They may be taped in place to keep them out of the way before proceeding.

C. By means of a hooked instrument , remove packing (6) ensuring not to damage the sealing surfaces of the packing box or plug stem.

Note: On valves equipped with an optional lubricator connection, the lantern ring (7) must also be removed to gain access to lower packing rings.

Plug stem pinning in the field may be required for the following:

• Replacing existing plug and stem, or

If it is necessary to replace the plug, then the plug stem must be replaced at the same time. The original pin hole in an existing stem will not provide the necessary fit , and might seriously impair the strength of the assembly.

A. Reference marking on the Plug Stem Measure the depth of the pilot recess in the plug (Dimension X in Figure 6), and make a reference mark on the plug stem at the same distance from the thread.

• Hold the plug (with vise jaw assembly) in a vise.

Lapping is the process of working the valve plug against the seat ring with an abrasive to produce a close fit . If valve leakage is excessive, lapping becomes necessary.

The plug andseat ring seating surfaces should be free of large scratches orother defects, and the contact surfaces of the seats should be as narrow as possible. This may require dressing both parts in a lathe. The seating surface angle of the plug is 28 degrees and the seat ring is 30 degrees (relative to the centerline axis).

A good grade of fine grinding compound is required for the lapping operation.

The compound should be mixed with a small quantity of lubricant such as graphite. This will slow the cutting rate and prevent tearing of the seating surfaces. The amount of lapping required depends on the materials, condition of seating surfaces, and accuracy of machining.

lf a short period of lapping does not visibly improve seating, there is usually no advantage in continuing as excessive lapping may result in rough seats.

The only remedy is replacement or re-machining of one or both parts. When lapping new plugs and seat rings, begin with a medium fine (240 grit) and finish with a finer grade (600 grit).

1. CIean body gasket surface areas.