Cashco DA1 - Manual (Page 7)

7 IOM-DA1
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
“ledges” formed due to wear from
moving dynamic side seal (27) or
wiper seal (16).
c. Lower guide bushing (24) (non-replace-
able):
1. 16
rms fi nish on bore.
2. Max 0.015 inch (0.38 mm) clearance
be tween valve plug (20) spindle and
lower guide bushing (24).
d. Internal sensing drilled plug (32);
1. Ensure that bore is minimum 0.125
inch (3.20 mm). Drill out as re-
quired.
4. Staging Material for Reassembly.
a. Inspect and clean parts, as necessary,
from the spare parts kit. (See Article
VI.A.4. comments concerning cleaning
for ox y gen service.)
b. Lay out all the regulator parts and check
against the bill of material.
E. Reassembly of the ITA:
1. When replacing the optional wiper seal (16),
the replacement wiper seal (16) is “pre-
formed”. It will, however, require re form ing.
Reform the wiper seal (16) by press ing the
temporary assembly parts into the cage (19)
backwards as shown in Figure 4. The wiper
seal (16) is best left in this position overnight,
but a min i mum of two (2) hours prior to re as -
sem bly.
2. After forming the wiper seal, remove parts
(13, 16, 17) from cage (19) and disassemble
the tem po rary assembly of Step 1. above.
3. Installation of dynamic side seal (27) (See
Figure 1):
a. Type
OR:
1. Stretch o-ring seal (27.4) over
lower cir cum fer ence of piston-guide
bearing (13), tak ing care not to “cut”
o-ring seal (27.4). Using thumbs, work
the o-ring seal (27.4) up and into the
groove of the piston-guide bearing
(13). NOTE: A very slight amount
of fl uid and elas tomer compatible
lubricant is rec om mend ed as an
installation aid.
2. For metal diaphragm construction,
insert cam ber adjusting washer (17.2)
into cage (19) and allow to rest in the
bottom of the cage (19).
3. Position piston-guide bearing (13)
over upper end of cage (19) prop-
erly oriented. Using thumbs, evenly
press piston-guide bearing (13) into
the cage (19), ensuring not to “cut”
o-ring seal (27.4). Continue press-
ing pis ton-guide bearing (13) until in
approximate fi nal position.
Figure 4
b. Type CP:
1. Stretch o-ring energizer/seal (27.2)
over low er cir cum fer ence of piston-
guide bear ing (13), tak ing care not
to “cut” o-ring energizer/seal (27.4).
Using thumbs, work the o-ring en-
ergizer/seal (27.4) up and into the
groove of the piston-guide bear ing
(13). NOTE: A very slight amount
of fl uid and elas tomer compatible
lubricant is rec om mend ed as an
installation aid.
2. For metal diaphragm construction,
insert cam ber adjusting washer (17.2)
into cage (19) and allow to rest in the
bottom of the cage (19).
3. Position TFE cap seal (27.1) ring
with rectangular cross-section at
end of pis ton-guide bearing (13).
Stretch cap seal (27.1) over lower
end of piston-guide bear ing (13) using
thumbs to work the cap seal (27.1)
onto the piston-guide bearing (13).
DO NOT USE A TOOL FOR THIS
STEP. Continue pressing cap seal
(27.1) up wards towards the groove
until the cap seal (27.1) “snaps” into
the groove of the piston-guide bearing
(13).
Not supplied. Use any
bolt, washers (2) and
nut of same approximate
hole size.
17
19
16
13