49Mv22/72 - Baker Hughes Consolidated 4900 Series Instruction Manual

XVII. Pilot Valve Part Inspection (Cont.)
9. Spring Washer(s): Galling at the spherical
bearing surface. Check for any corrosion or
pitting.
10. Pilot Base: Check for any corrosion or pitting.
Also, check for galling of threads.
11. Spring: Check for any corrosion or pitting.
12. Modulator Stop: Top seating surface for cuts
or deformities. The surface can be lapped if the
distance from the seat to the outside shoulder
does not reduce to less than .086" (2.18 mm).
13. O-Ring Retainer: Seating surface for cuts or
deformities. The surface can be lapped if the
overall height of the part does not reduce to less
than .160" (4.06 mm). Also, check the outside
diameter for any scratches that might prevent the
O-Ring (Modulator Seat) from sealing.
14. Modulator Piston Bottom: Galling or
excessive wear on the outside diameter that
rubs against the Modulator Base. Make sure that
the lip holding the O-Ring (Modulator Seat) is
not deformed. Also, check the outside diameter
of the O-Ring groove for scratches that might
cause the O-Ring (Modulator Seat) not to seal.
Check for any corrosion or pitting.
15. Modulator Base: Galling or excessive wear on
any inside diameter. Any corrosion or pitting.
C. 49MV22/72
1. Main Piston: Galling or excessive wear on the
diameter where the Spring Seal (Main Piston)
engages or on the spherical bearing surface.
Any corrosion or pitting that appears detrimental
to the function of the valve. The part can be
polished as long as the outside diameter of
where the Spring Seal (Main Piston) rides must
be .970"±.001" (24.64±0.03 mm) on 49MV22
model or .812"±.001" (20.63±0.03 mm) on
49MV72. A surface finish of 8 RMS must be
maintained for proper sealing on these surfaces.
2. Piston Nose: Galling or excessive wear on the
diameter where the spring seals engage. Any
corrosion or pitting that appears detrimental
to the function of the valve. The part can be
polished as long as the outside diameter of the
stem remains at .243"±.001" (6.17±0.03 mm).
The stem itself must have a T.I.R of .001" (0.03
mm) along its length.
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Baker Hughes
3. Insert Top: Galling or excessive wear on the
inside diameter that guides the Main Piston.
Check for any corrosion or pitting. Also, check
for galling of threads.
4. Insert Bottom: Galling or excessive wear on
the inside diameter that guides the Main Piston.
Check for any corrosion or pitting.
5. Adjuster Top: Galling or excessive wear on
the inside diameter that guides the Main Piston.
Check for any corrosion or pitting. Also, check
for galling of threads.
6. Adjuster Bottom: Galling or excessive wear on
the inside diameter that guides the Main Piston.
Check for any corrosion or pitting. Also, check
for galling of threads.
7. Balance Seal Adaptor: Check for any
corrosion or pitting.
8. Top Plate: Galling or excessive wear on the
inside diameter that guides the Main Piston.
Check for any corrosion or pitting. Also, check
for galling of threads.
9. Bonnet: Check for any corrosion or pitting.
Also, check for galling of threads for the
compression screw and where it attaches to the
Pilot Base.
10. Compression Screw: Galling at the spherical
bearing surface or in the thread. Check for any
corrosion or pitting.
11. Spring Washer(s): Galling at the spherical
bearing surface. Check for any corrosion or
pitting.
12. Pilot Base: Check for any corrosion or pitting.
Also, check for galling of threads.
13. Spring: Check for any corrosion or pitting.
If any damage listed above is present, the part
should be replaced or repaired per instruction.
Other valve parts may be acceptable with light
corrosion, pitting, or minor damage of other types
if it can be determined that it will not affect product
performance. All O-Rings and spring seals should
be replaced each time the valve is disassembled.
Refer to Tables 12 and 13 for O-Ring/Spring Seal
repair kits. Recommended spare parts are listed in
Table 10.
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