Cashco 964 - Manual (Page 6)

IOM-964 6
Figure 3: Composition Seat Ar range ment
a. Examine stem (3) in critical fi nish zone
where contact is made with the packing
(6). It is desirable to restore the surface
of the stem (3) to a #8 Ra μ-in surface
fi nish; metal removal should not exceed
0.001-inch material. A deeply scratched
or pitted stem (3) should be replaced.
b. Plug head of stem (3) assembly for metal
seated design may be hand lapped us-
ing suitable lapping com pound. If hand
lap ping will not restore surface fi nish to
an ac cept able de gree, the re place ment
of stem (3) as sem bly and seat ring (11)
is rec om mend ed.
c. For composition seated design, the TFE
valve seat (3.4) can be replaced if the
adapt ers (3.3/3.5), cotter pin (3.2) and
castle nut (3.6) are not wear dam aged.
Grip stem (3.1) in vise (using pro tec-
tive cov er ing (directly above (3.3/3.5)
adapter ). Re move cot ter pin (3.2), castle
nut (3.6), adapt er (3.3 or 3.5) and valve
seat (3.4). Insert new valve seat (3.4) and
re as sem ble to desired seat ar range ment.
See Fig ure 3.
18. Examine the inner surface of the bonnet’s
(2) stuffi ng box. It is desirable to restore the
surface of stuffi ng box to a #16 Ra μ-in sur-
face fi nish; metal removal should not exceed
0.001-inch material. A deeply scratched or
pitted bonnet (2) should be replaced.
19. Examine packing follower (5) for corrosion.
Replace if signifi cantly corroded:
a. Remove follower bushing (25) from inside of
packing follower (5) and replace with new.
20. Remove gaskets (12) (13), clean gas ket fac ing
sur fac es and replace with new gas kets (12) (13).
21. For ATO-FC action units, place seat ring (11)
over end of stem (3) in proper ori en ta tion, and
insert the stem (3) until it ap pears thru the top
side of the bonnet (2). See Figure 6.
22. For ATC-FO action units, place seat ring (11)
into the body (1) cavity. Insert the stem (3) until
it ap pears thru the top side of the bonnet (2).
See Figure 7.
23. Lower packing spring (24) into bonnet (2)
pack ing box.
24. Lower packing washer (23) into bonnet (2)
packing box. Ensure that wash er (23) is rest-
ing fl at on the packing spring (24).
Figure 4: Packing Orientation
25. See Figure 4 for proper packing orientation.
a. Carefully place lower adapter (6.3) of
packing ring set (6) over stem’s (3) end,
properly oriented. Using the packing fol-
lower (5), push the lower adapter into the
bonnet’s (2) stuffi ng box.
b. Carefully place a packing ring (6.2) prop-
erly oriented over the stem’s (3) end and
push into the stuffi ng box similar to the
adapter (6.3). Repeat to each of the four
rings (6.2).
c. Carefully place upper adapter (6.1) over
the stem’s (3) end.
26. Slide packing follower (5) with new follower
bushing (25) over end of stem.
27. Place packing fl ange (4) over end of stem (3)
and over packing studs (14).
28. Slide position indicator disc (20) and accessory
plate ((AP)), in installed, over end of stem (3).