Cashco 521 - Manual (Page 7)

IOM-521 7
The valve body (1) is ma chined after the shell
halves (1.1) have been bolted (1.3, 1.4, 1.5)
around the TFE core (1.2). Dis as sem bly of
the body sub-assembly (1) will cre ate align-
ment problems during reassembly. The
TFE core (1.2) is not replaceable, except
as a body sub-as sem bly (1).
10. Make a visual inspection of the trim portions
still in ter con nect ed to the actuator assembly
(AA) for ob vi ous problems.
11. Hand-grasp the bellows sub-assembly
(8) and rotate CCW (viewed from plug (3)
end) to removal. Do not use any wrench,
vise, etc., for grasping the bellows sub-
assembly (8)! The bellows (8) should only
be hand-tight.
12. Loosen packing gland nut (5) 2-3 revolu-
tions out of the bonnet (2) by rotating CCW
(viewed from stem (9) end).
13. Loosen jam nut (20) 1-2 revolutions.
14. Grasp the valve’s stem sub-assembly (9)
in the lower area (normally surrounded by
the bellows (8.1)) using soft jawed pliers
to pre vent marring stem surface. Place
a wrench on the hex surface of the swivel
lower knuckle (44) and rotate knuckle CW
(viewed from plug (3) end) until lower knuckle
dis-engages from stem (9). Keep track of
the number of full rev o lu tions to dis-engage
and record here. _______________
15. Retract the stem sub-assembly (9) down-
wards thru the bonnet (2) until stopped by
locknut (20). Rotate lock nut (20), CCW until
it is removed.
16. Fully withdraw stem sub-assembly (9).
17. Visually inspect parts for wear, general
cor ro sion, localized corrosion, dirty service
fl uid, uneven alignment, seat leakage wire
draw ing, excess plug-to-seat loading, fl ange
fac ings, looseness of plug-to-bellows con-
nec tion, primary seal at TFE Core (1.2)
-to-bel lows (8.1) joint, secondary seat at
bonnet gasket (11) (See Figure 9), blisters
on TFE sur fac es, etc.
18. Attempt to determine the reason for a failure.
Evaluate if process conditions need cor rec-
tion, if alternate materials are required for
the stem sub-assembly (9), or if effects of
10. Raise the actuator assembly (AA) over stem
(9). Release any ac tu a tor air pressure. Lay
actuator assemby aside on work surface.
D. Body Disassembly:
1. Access to body assembly (BA) internals
may be accomplished with the actuator as-
sembly (AA) intact with the bonnet (2) (i.e.
locknut (15) is still fully tight ened), or with
the body assembly (BA) separated as per
above para graph V.C. Steps 1-10.
2. Maintenance procedures hereinafter are
based upon the actuator assembly (AA) fully
in ter con nect ed with the valve stem assembly
(9) during disassembly.
3. Secure the body in a vise with the actuator
assembly (AA) oriented vertically upwards.
Place matchmarks between the body (1)
bon net fl ange and the bonnet (2) fl ange to
assist in fi nal ori en ta tion when the body is
dis as sem bled and/or the ac tu a tor removed.
4. Secure and rig the actuator assembly (AA)
for a ver ti cal lift using an overhead hoist.
Remove slack from rigging.
5. Loosen all bon net cap screws (14) ap prox i-
mate ly 1/4" (6 mm) by rotating CCW (viewed
from above).
6. Raise actuator assembly (AA) with overhead
hoist approximately 1/8" (3 mm).
7. Continue to loosen and remove bonnet cap
screws (14 and lockwashers (13).
8. Using overhead hoist, lift the actuator as sem-
bly (AA) with the interconnected valve stem
sub-as sem bly (9), bellows sub-assembly
(8), bonnet (2), bonnet spacer (19), locknut
(15), packing gland nut (5), packing rings
(6), Belleville spring washers (7), bonnet
gas ket (11), plug (3) and plug retainer (4).
Lay this as sem bly down on a horizontal work
surface carefully, so as to not damage the
valve’s internals.
9. Make a visual inspection of the body sub-
assembly (1) exterior, which includes two
shell halves (1.1), TFE core (1.2), and four
body cap screws (1.3) with body nuts (1.4)
and lock wash ers (1.5).
NOTE: DO NOT DISASSEMBLE THE PARTS
OF THE BODY SUB-ASSEMBLY (1)!