Baker Hughes Masoneilan 525 Seris, Инструкция по эксплуатации

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3. lnstall and tighten seat rings using fabricated wrench used
for removal.
Do not over-tighten. Do not strike seat ring lugs di-
rectly. This could distort the seat ring resulting in seat
leakage.
4. Apply lapping compound on the plugs at several spots
equally spaced around the seating area.
5. lnsert the stem and plug sub-assembly carefully into the
body until it is seated.
6. Place bonnet (8) on the body and fasten the bonnet to the
body using four body stud nuts (10) spaced equally apart.
Apply slight pressure and tighten evenly.
Donottightennutstofinaltorquespecificationsat
this time. The bonnet is used temporarily for guiding
purposes only.
7. lnsert two or three pieces of packing (16) into the packing
box to assist in guiding the stem and plug during lapping.
8. Screw a drilled and tapped rod with a T-handle onto the plug
stem and secure with a locknut (see Figure 3).
Note: As an alternative, drill a hole through a flat steel
plate and fasten to the plug stem using two locknuts.
9. Apply slight upward pressure on the stem to establish seating
contact, and rotate the stem in short oscillating strokes
(around 8 to 10 times). Repeat this step as necessary.
Note: The plug should be lifted and turned 90° each
time before repeating Step (9). This intermittent lifting
is required to keep the plug and seat rings concentric
during lapping.
10. Avoid over-lapping as this can cause damage to the seating
surface rather than improve leakage performance.
11. After completion of the lapping operation, remove bonnet
and plug. The seating area of the seat ring and the plug
must be cleaned of all lapping compound in preparation for
reassembly. Do not remove seat ring.
7.4 Pinning
Valve plug and stem assemblies are normally furnished as a
complete assembly in which case the installation involves no
further assembly steps. It is only necessary to lap the plug and
seat ring and assemble the valve. If it is necessary to replace the
plug it is recommended that a new stem be used. If the old stem
must be used, it is necessary to determine if the stem will be long
enough since the stem will require cutting. If the stem does not
engage the actuator stem by a minimum of one stem diameter,
the old stem should not be used. If it does engage a minimum of
one stem diameter, proceed as follows.
Note: While pinning is being performed, care must be taken
not to damage the seating surface and plug guides.
A. Using a drift punch, drive out the old pin (8).
Note: If it is necessary to drill out the pin, a drill
somewhat smaller than the pin should be used and the
remainder of the pin driven out.
B. Unscrew the plug from the stem (counter clock-wise).
C. Measure threaded portion of the stem.
D. Cut off the stem directly above the existing pin hole.
E. Rethread the stem to the original amount.
Note: The area of the plug stem marked X in Figure 4
serves as a guide and must be checked to ensure a
close fit in the valve plug.
F. Screw the stem solidly into the plug.
Note: This can be checked by measuring the depth of
the pilot recess in the plug (X in Figure 4), and making a
reference mark on the stem the same distance from the
thread. When properly assembled, the reference mark
should be flush with the end of the guide section.
G. Place the plug guide on a V block and using a suitable size
drill, drill the stem using the hole in the plug as a guide.
H. Remove any burrs from the plug guide by making a slight
counter bore.
I. Select the correct size pin, apply a small amount of grease
on it and press into the hole.
Note: The pin must be recessed approximately 1/16”
below the plug guide surface.
J. After the plug has been pinned it should be placed in a lathe
to ensure it is running true. If it is not, strike the plug with a
soft faced mallet to straighten.
Note: The plug should be placed in a collet with the plug
guide against it and the plug should be struck.
7.5 Packing Box
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 (15) against the packing flange
(13). 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.
Valve must be isolated and the pressure vented be-
fore performing packing box maintenance.
Proceed as follows:
7.5.1 Carbon/PTFE Rings (Standard)
Note: The Carbon/PTFE packing rings have a skive cut
allowing packing replacement without disconnecting the
plug stem from the actuator connector or actuator stem.
A. Loosen and remove packing flange nuts (15).
B. Lift the packing flange (13) and packing follower (12) up the
valve stem.
Note: These parts may be secured using tape or wire to
keep them out of the way before proceeding.