IOM-PGR-1
5
3. QC
Requirements:
a. Valve plug (5);
1. 16 rms finish on its seating surface
for tight shutoff.
2. No major defects on bottom guide
spin dle.
b. Cage
(4);
1. 16 rms finish 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-re place-
able):
1. 16 rms finish 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 required.
4. Staging Material for Reassembly.
a. Inspect and clean parts, as necessary,
from the spare parts kit. (See Article VII
A.4. comments for special cleaning.
b. Lay out all the regulator parts and check
against the bill of material.
E. Reassembly of the ITA:
1. Installation of dynamic side seal (15).
a. Type
OR:
1. Stretch o-ring seal (15) over lower
cir cum fer ence of guide bear ing (9),
tak ing care not to “cut” o-ring seal.
Using thumbs, work the o-ring seal
up and into the groove of the guide
bearing.
NOTE:
A very slight amount
of fluid and elas tomer compatible
lu bri cant is rec om mend ed as an
in stal la tion aid.
2.
Position guide bearing (9) over top
of the upper end of cage (4) properly
oriented. Using thumbs, evenly press
guide bearing into the cage, ensur-
ing not to “cut” o-ring seal. Continue
pressing guide bearing into cage until
in ap prox i mate final position.
b. Type
UC:
1. Stretch u-cup seal (15.1) over lower
circumference of guide bear ing (9),
taking care not to “cut” u-cup seal on
the protruding shelf that is part of the
guide bear ing's groove. Ensure that
the u-cup seal is oriented with the
center-open-downwards as shown
in image below, as the u-cup seal
depends upon the P1-Inlet Pres sure
to pressure activate the seal for proper
sealing action.
2. Position guide bearing (9) over top
of the upper end of cage (4) properly
oriented, until the cup seal edge
touches the upper lip of the cage
(4). While gently applying force to
press the guide bearing (9) into the
cage, simultaneously use fingers to
lightly press the edges of the u-cup
seal inwards into the groove of the
guide bearing until the u-cup seal
(15.1) “slips into” the cage (19). DO
NOT USE TOOLS, LUBRICANT, OR
HEAVY FORCE TO ENGAGE THE
U-CUP SEAL INTO THE CAGE .
Type OR
— O-Ring
Dynamic Seal
Type UC
— U-Cup
Dynamic Seal
