Cashco SA4 - Manual (Page 4)

IOM-CA4/SA4 4
d. Examine the com po nents (27.1, 27.2,
27.3) of the dy nam ic side seal (27) mech a-
nism to de ter mine if sig nifi cant leakage
was oc cur ring. If the dy nam ic side seal
shows signs of sig nifi cant leakage, de ter-
mine if op er at ing con di tions are ex ceed ing
pres sure, pres sure drop, or tem per a ture
lim its.
e. Remove dynamic side seal (27) com po-
nents and discard. Special care should be
taken when using “tools” to remove the
components to ensure that no scratches
are made to any portion of the piston- guide
bearing (13) groove.
f. Remove the shim (16) from within the
cage (19).
g. Remove seat ring (21); examine for signs
of leakage. If seat ring shows signs of
signifi cant leakage, determine if op er at ing
con di tions - pres sure, pressure drop, or
temperature ex ceed ddesign lim its.
2. Clean all metal parts to be reused according
to owner's procedures. NOTE: Regulators are
originally supplied with a level of clean li ness
equal to Cashco cleaning standard #S-1662.
Contact factory for details.
D. Inspection of Parts:
1. Remove and dis card the fol low ing parts:
o-ring (15), diaphragm(s) (9), seals (27, 28),
and seat ring (21). These parts MUST be
re placed with fac to ry supplied new parts.
2. Inspect the metal parts that will be reused. The
parts should be free of surface con tam i nants,
burrs, oxides, and scale. Rework and clean
the parts as necessary. Surface con di tions
that affect the regulator performance are stated
below; re place parts that can not be re worked
or cleaned.
3. QC Requirements:
a. Valve plug (20);
1. 16 rms fi nish on its seating surface
for tight shutoff.
2. No major defects on bottom guide
spin dle.
b. Cage (19);
1. 16 rms fi nish on cylinder bore. No
“ledg es” formed due to wear from
moving dynamic side seal (27) or plug
(20).
C. Disassembly of the ITA:
1. To Disassemble the ITA (See Figure 2):
a. Hold the lower part of the valve plug
(20) in a bench vise; grasp in "smooth
jaws" directly under plug's (20) seating
disc portion on hub "fl ats" provided. Do
not hold on the ma chined sur face in the
plug's (20) spin dle area.
b. Using a special double-posted spanner
wrench fi tting, (to order see NOTE in
Section IX Parts Ordering Information),
turn the pis ton-guide bear ing (13) CCW
to loosen. The piston-guide bear ing (13)
may be re moved by hand after loos en ing.
c. Remove ITA from vise. Pull the valve plug
(20) down and out through the cage's (19)
bottom opening.
Figure 2: Assembled ITA, with
"UC" Dynamic Side Seal
in single revolution increments. The reg u la tor
con tains a lower return spring (22); the ITA
should rise as the cage cap screws (18) are
backed out evenly. A downward holding force
should be ap plied to the top of the piston-guide
bearing (13) to pre vent the ITA from pop ping
up as the last threads of the cage cap screws
(18) are disengaged. Remove washers (17).
6. Remove the ITA by pull ing up on the piston-
guide bearing (13). Set ITA aside.
7. Remove the lower return spring (22) from
within the body (23).
8. Remove the cage o-ring seal (15).
9. Remove metal C-ring seal (28) from body (23)
di a phragm fl ange groove.
10. Clean all metal parts to be reused according to
owner's procedures. NOTE: Regulators are
originally supplied with a level of clean li ness
equal to Cashco cleaning standard #S-1662.
Contact factory for details.
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