Baker Hughes Large Mass Flow Energy Management Control Valves 72000 Series

- For Models that use a conical spring design, always inspect the body bore surface adjacent to where the conical spring (14) is seated. If this surface has been deformed or if there is a groove where the seal seats, the surface should be cleaned and honed prior to reassembling the valve.

- If the refinishing procedure is unsuccessful, the factory should be consulted for further instructions.;

Gasket seating surfaces must be free of dents, scratches, corrosion, or other types of damage. Clean mating surfaces as required and replace any non-conforming parts. Spiral wound gaskets (Items 25, 26 & 27) must always be replaced after disassembly.;

- Prior to reassembly, examine parts carefully for any scratches, unusual wear, or other damage.; Guiding surfaces of the cage, valve plug, guide bushing, plug stem, and auxiliary pilot plug must be checked. If there are only slight wear indications, then gently use a light abrasive, such as Scotchbrite® or fine grit sandpaper, to smooth out guiding surfaces. Parts with significant damage or wear on the guiding surfaces must be replaced.;

For the two piece bonnet configurations: - Prior to reassembly, the metal seal (6) should be inspected for cracks or signs of wear. The metal seal can be reused if it is free from scratches, erosion, corrosion, or any other type of damage.

- If slight wear exists on the metal seal, a new layer of coating should be re-applied to the original condition by the factory or a Masoneilan Authorized Repair Center (MARC'). For emergency repairs in the field, the metal seal may be coated with a molybdenum disulfide based spray on lubricant such as MolyKote®.

- Prior to reassembly of the valve, inspect the inside of the valve body around the area where the metal seal seats. It is common to find slight ridges or depressions from where the seal was originally seated. During initial assembly these depressions aid in the sealing of the valve, however these areas can become leak paths during reassembly if the surface is not restored to its original finish as described below.

- To prevent this potential leakage, machine the seating angle of the bonnet at 40 degrees by approximately 0.1 inches (2.5 mm) deep, thus causing the metal seal to seat further down inside the valve body (on a new undeformed surface). Refer to Figure 7 for details.;

- Tight sealing within the packing box is obtained by compression of the packing (19).; Compression must be achieved by evenly tightening the packing flange nuts (16) on the packing flange (17).; Periodic re-tightening of the packing flange nuts may be required to maintain proper sealing.

- Be careful not to over tighten the packing as this could prevent proper operation of the valve.; If leakage persists after maximum packing compression, then the packing needs to be changed.;