Cashco SA4 - Manual (Page 6)

IOM-CA4/SA4 6
DO NOT HIGH STATIC PRESSURE TEST
THE BODY WITH OUT LOADING CHAMBER
PRES SUR IZED. NOT ADHERING WILL DO
PHYSICAL DAMAGE TO INTERNALS THAT
COULD REN DER THE UNIT INOPERABLE.
2. Seat Leakage Test.
a. Release all loading pressure from loading
chamber.
b. Pressurize inlet to 50 psig (3.5 Barg) with
UHP grade GN2.
c. Tube outlet to a beaker of water to ob-
serve number of escaping gas bubbles.
A steady fl ow of gas bubbles (e.g., 20
bub bles / minute or greater) is ex ces sive
leakage.
3. Excessive leakage will require disassembly,
examination of sealing elements, correction of
problem, reassembly and retesting. Leakage
path may be via plug/seat or dynamic side
seal.
NOTE: If disassembly and re-testing is
required, the metal C-ring seal (28) MUST
be re placed for each disassembly/re as-
sem bly.
5. Units with CTFE or VTFE seat ring (21): Due to
the relative "hardness" of the CTFE and VTFE
material, to obtain the best possible shutoff
it is nec es sary to generate a "coined" seating
chamfer.
6. To coin the seat ring:
a. Close-off the outlet connection.
b. The level of seat leakage can be quan ti-
fi ed at the internal sensing passage.
c. Pressurize the regulator's inlet with
50–100 psig (3.5–6.9 Barg) of UHP grade
GN2.
d. Place a thin, fl exible membrane that more
than covers the diaphragm fl ange cavity
of the body (23).
e. Using a soft-headed mallet (rubber,
leath er), sharply rap the thin membrane
over the top,center end of the piston-guide
bear ing (13). (Note: Gas will escape as
the plug (20) is momentarily forced off
the seat ring (21). Allow suf fi cient time
for leak age pres sure on outlet side to
bleed-off.) The ham mer rap should be
strong enough to "bounce" the plug (20)
into the seat ring (21), leav ing a "coined"
seating chamfer. Repeat a minimum of
2 times. Check after each rap to see if
re quired shut off is obtained.
f. After "coining" is complete, remove UHP
grade GN2 pres sure source, membrane
and open out let.
7. To Install Diaphragm(s):
a. Install a new metal C-ring seal (28) into
the body (23) diaphragm fl ange groove.
b. Center diaphragm(s) (9) onto body's (23)
diaphragm fl ange.
8. Aligning matchmarks and bolt holes, place
loading chamber (4) on body (23).
9. Install all fl ange bolts (12) and nuts (11) with
nameplate (99) located under one bolt head.
Hand-tighten nuts (11).
10. Evenly tighten body bolting (11,12) using an
alternating cross pattern in one revolution
increments. Tighten to the following torque
value: All body sizes: 30-35 Ft-lbs (41-47 Nm).
G. Pressure Testing:
1. If a high static pressure test is performed,
pres sure must be applied to all three, the
loading chamber, the inlet and the outlet of
body at the same level.