4.
MAINTENANCE
4.1
General
Good operating procedure requires periodic observation
to ensure that the valve is functioning well. The frequency
of observation will depend on the application. Routine
maintenance consists of tightening the hex nuts (item 18
in
Figure 8
) periodically to compensate for stem seal wear.
Stem nut torque should be about 350 in.-lb.
Overhaul maintenance consists of replacing seats and
seals. A standard repair kit consisting of these parts may be
obtained through your authorized Metso Distributor.
NOTE:
Repair kits include thrust bearings (70), secondary
stem seal (71), seats (7), body seal (65) and stem seals (69).
Refer to the Repair Kit chart (see
Table 1
).
WARNING
FOR YOUR SAFETY IT IS IMPORTANT THE FOLLOWING PRECAUTIONS
BE TAKEN PRIOR TO REMOVAL OF THE VALVE FROM THE TANK CAR
OR BEFORE ANY DISASSEMBLY:
1.
WEAR ANY PROTECTIVE CLOTHING OR EQUIPMENT NORMALLY
REQUIRED WHEN WORKING WITH THE FLUID INVOLVED.
2.
DEPRESSURIZE THE TANK CAR AND CYCLE THE VALVE AS
FOLLOWS:
A. PLACE THE VALVE IN THE OPEN POSITION AND DRAIN THE
TANK CAR.
B. CYCLE THE VALVE TO RELIEVE RESIDUAL PRESSURE IN THE
BODY CAVITY BEFORE REMOVAL FROM THE TANK CAR.
C. AFTER REMOVAL AND BEFORE ANY DISASSEMBLY, CYCLE
THE VALVE AGAIN SEVERAL TIMES.
4.2
Disassembly
NOTE:
lf complete disassembly becomes necessary; it is
recommended to replace all seats and seals. Refer to the
Repair Kit chart (see
Table 1
).
NOTE:
Always use original OEM parts to make sure that the
valve functions properly.
1. Follow the steps in all the
WARNING
sections above
before performing any work on the valve.
2. Open and close the valve and leave in the closed
position. Valve needs to be raised above the working
surface slightly because the ball protrudes slightly from
either end of the valve when in the closed position.
3. Remove handle pin (35), handle (31) from top of stem;
if present.
4. Remove the retaining ring (34) and hex nuts (18).
5. Remove the disc springs (76), flat washers (77), indicator
stop (32), stop bushings (39), compression plate (10)
and compression ring (9).
6. Compress the insert (2), using a maximum load of
18,600 lbs., to relieve tension from the socket head cap
screws (73). The load must be evenly distributed around
the flange of the insert. Ensure that the socket head cap
screws (73) are not obscured.
7. Remove the six socket head cap screws (73). Slowly
relieve the load on the insert (2). Remove insert (2) from
the body (1) by tightening the set screws (72) evenly
and alternately until the insert (2) can be removed.
Should the insert (2) remain jammed in the valve, place
the ball in the partially open position. Using a wooden
or plastic rod and mallet, tap the insert from inside the
valve. Do not use a metal rod or hammer on any valve
component.
BE CAREFUL NOT TO SCRATCH THE BALL
.
NOTE:
In the event that a socket head cap screw (73) breaks;
break the shape edges. Beware of handling the valve as
sheared components may have sharp edges. Reduce the
remnant of the cap screw to a level flush with the surface.
Be careful not to damage any sealing surfaces.
WARNING
THE SOCKET HEAD CAP SCREWS (73) ARE USED FOR ASSEMBLY
PURPOSES ONLY. THE SCREWS ARE NOT CONSIDERED PRESSURE
RETAINING. A MINIMUM OF TWO SOCKET HEAD CAP SCREWS
(73) OPPOSITE EACH OTHER ARE REQUIRED TO ASSURE PROPER
ALIGNMENT AND SECURE THE INSERT (2).
8. Remove the body seal (65) and the seat (7), if the seat
did not come out with the insert from the insert (2).
9. If the ball (3) does not swing free from the body, with
the ball in the fully closed position, use a piece of wood
or some other soft material to gently tap the ball (from
the end opposite the body cap). This should loosen the
ball so that it can be pivoted free of the stem (5).
10. Carefully remove the bottom seat (7) out of the body,
BEING CAREFUL NOT TO SCRATCH THE BODY
SEALING SURFACE BEHIND THE SEAT.
NOTE:
If the valve has Barrier seats, (see
Section 4.6.1
) for
Barrier seat disassembly.
11. Press the stem (5) from the top into the valve body and
remove it through the insert end of the body.
12. Remove and discard the lower stem seals (70), and
secondary stem seal (71),
BEING CAREFUL NOT TO
SCRATCH ANY SEALING SURFACES INTHE BODY.
13. Remove the packing (69),
BEING CAREFUL NOT TO
SCRATCH ANY SEALING SURFACE INSIDE THE STEM
BORE.
4.3
Checking Parts
NOTE:
For detailed instructions on visual inspection of
critical components, refer to IMO-R26.
1. Clean all disassembled parts.
2. Check the stem (5) and ball (3) for damage. Pay particular
attention to the sealing areas.
3. Check all sealing and gasket surfaces of the body (1)
and insert (2).
4. Replace any damaged parts.
IMO
4/19
IMO-R20 EN
5
