Cashco DA4 - Manual (Page 11)

IOM-DA4 11
a. Body (23) is specially machined with a
shelf to capture a lower diaphragm sup-
port ring (35).
b. Cover dome (25) is specially machined to
provide a surface for the upper di a phragm
(9) support. Lower diaphragm support ring
(35) is captured by its location. Upon re-
moval of cover dome (25) and di a phragm
(9), the lower diaphragm support ring (35)
can be lifted upwards and out of the body
(23) cavity.
c. Reinstallation is a reversal of Step b.
above.
DO NOT HYDROSTATICALLY TEST WITH-
OUT COVER DOME PRESSURIZED. NOT
AD HER ING WILL DO PHYSICAL DAMAGE
TO INTERNALS THAT COULD REN DER
THE UNIT IN OP ER A BLE.
2. Inboard Leakage Test.
a. Release all loading pressure in cover
dome.
b. Pressurize inlet to 30 psig (2.1 Barg) with
air, GN
2
.
c. Tube outlet to a beaker of water to ob serve
number of escaping gas bubbles.
Inboard leakage path may be via plug/seat or
dynamic side seal.
3. Pressure Containment Test.
a. Pressurize inlet to 200 psig (13.8 Barg)
and outlet and cover dome to 150 psig
(10.3 Barg) with air or GN
2
.
b. Spray liquid lead detector and check all
ex ter nal leak points; i.e. plugged con nec-
tions, di a phragm fl ange and di a phragm
bolting.
4. Excessive leakage will require disassembly,
examination of sealing elements, correction
of problem, reassembly and retesting.
Figure 5: Opt-81 — Composition Diaphragm
Con struc tion, 2" (DN50) and Smaller
H. Converting Internal/External Sensing:
1. Disassemble the regulator and remove the
diaphragm(s) (9) according to Steps 1-12 in
Part B – Main Regulator Disassembly.
2. To convert from internal to external sensing,
remove the drilled pipe plug (32) and install a
solid pipe plug. Reverse this step for convert-
ing from external to internal sensing.
3. Reassemble the regulator according to Part
F – Main Regulator Reassembly.
I. Pressure Testing:
1. If a hydrostatic pressure test is performed,
pressure must be applied to all three of cover
dome (25), inlet and outlet of body at the same
level.
Figure 6: Location of Auxiliary Ports