Cashco SA4 User Manual
INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)
IOM-CA4/SA4
MODEL CA4/SA4
CA4 and SA4 - ULTRA HIGH PURITY, PRESSURE LOADED
PRESSURE REDUCING REGULATORS
SECTION I
I. DESCRIPTION AND SCOPE
Models CA4/SA4 are pressure reducing regulators used to control downstream (outlet or P2) pressure. Sizes are
3/4" (DN20), 1" (DN25), 1-1/2" (DN40), and 2" (DN50). With proper trim uti li za tion, the unit is suitable for liquid or
gaseous service. (NOTE: This product was formerly identifi ed as a Model C4 or S4; a Model CA4/SA4 and C4/S4
are one and the same product.)
SECTION II
11-13
II. REFERENCES
Refer to Technical Bulletin CA4/SA4-TB for tech ni-
cal specifi cations of a Model CA4/SA4 reg u la tor.
SECTION III
CAUTION
Installation of adequate overpressure pro tec tion
is recommended to pro tect the reg u la tor and all
downstream equip ment from dam age in the event
of reg u la tor failure.
III. INSTALLATION
1. Install per direction of fl ow arrow indicated on
body, or "IN" and "OUT" markings.
2. Regulator may be rotated around pipe axis 360
degrees. For ease of maintenance, the rec om mend ed orientation is with the loading chamber
(4) upwards.
ABBREVIATIONS
CCW – Counter Clockwise
CW – Clockwise
ITA – Inner Trim Assembly
CAUTION
DO NOT HYDROSTATIC TEST THROUGH AN
IN STALLED UNIT; ISOLATE REGULATOR FROM
TEST. The "Outlet" rating as printed on the
nameplate is the rec om mend ed “upper op er at ing limit” for the sens ing di a phragm. Higher
pres sures could cause internal dam age. In ad di tion, note on the nameplate that the Inlet and
Outlet pres sure and temperature ratings are at
different levels.
3. Provide space below, above, and around reg u la tor
for removal of parts during maintenance.
4. Install block valves and pressure gauges to pro vide means for adjustment, operation, bypass, or
removal of the regulator. A UHP fi lter is rec om-
mend ed before inlet to remove typical pipe line
debris from entering valve and damaging internal
“soft goods”, primarily the dynamic seal and valve
seat.
Recommended Piping Schematic
for Pressure Reducing Station
SECTION IV
IV. PRINCIPLE OF OPERATION
1. When a loading pressure – P
the top side of a diaphragm, the outlet controlled
pressure – P2 – will balance at approximately
.90 – .98 of the loading pressure - PL. (NOTE:
Fluc tu a tions in P1 – Inlet Pressure will cause a
deviation in P2 – Outlet Pressure due to inverse
sym pa thet ic ratio effect.) See Section VIII.
2. Movement occurs as pressure variations register
on the diaphragm. The registering pressure is the
outlet, P2, or downstream pressure. The loading
– is applied to
Load
V. STARTUP
1 Start with the block valves closed.
2. Adjust the loading system pressure control de vice
so that main regulator is trying to be con trolled at
0 psig pressure.
3. If it is a “hot” piping system, and equipped with
a bypass valve, slowly open the bypass valve
to preheat the system piping and to allow slow
ex pan sion of the piping. Closely monitor outlet
(down stream) pressure via gauge to ensure not
over-pressurizing. NOTE: If no bypass valve is
in stalled, extra caution should be used in start ing
up a cold system; i.e. do everything slowly.
CAUTION
Do not walk away and leave a bypassed reg u la tor unattended!
pressure fl uid op pos es di a phragm move ment.
As outlet pres sure drops, the loading pressure
push es the di a phragm down, opening the port; as
outlet pres sure increases, the diaphragm pushes
up and the port opening closes.
3. A diaphragm failure will tend to cause the reg u la tor
to fall below setpoint. A loss of loading pres sure
while inlet pressure is imposed will cause the
regulator to fail close. A com plete diaphragm failure
will cause the inlet process fl uid to mix with the
loading fl uid.
SECTION V
tor is fl owing. If not, slowly increase the loading
pressure into the cover dome until fl ow be gins.
6. Continue to slowly open the inlet (upstream) block
valve until fully open.
7. Continue to slowly open the outlet (downstream)
block valve, especially when the downstream piping system isn’t pressurized. If the outlet (down stream) pressure exceeds the desired pres sure,
close the inlet block valve and go to Step 2. Close
bypass valve approximately 25%, and re peat
pro ce dure.
8. When fl ow is established steady enough that the
outlet (downstream) block valve is fully open, begin
to slowly close the bypass valve if installed.
9. Develop system fl ow to a level near its expected
normal rate, and reset the regulator set point by
increasing the loading pressure to increase outlet
pressure, or decreasing the loading pressure to
reduce outlet pres sure.
4. Crack open the outlet (downstream) block valve
to approximately 10% full open.
5. Slowly open the inlet (upstream) block valve to
about 25% open, observing the outlet (down stream) pres sure gauge. Determine if the reg u la-
VI. SHUTDOWN
1. Shutoff auxiliary loading pressure source. Close
inlet block valve.
2
10. Reduce system fl ow to a minimum level and ob-
serve pressure set point. Outlet pressure will rise
from the set point of Step 9. The maximum rise
in outlet pressure on decreasing fl ow should not
exceed the stated upper limit of the range spring
by greater than 10%. If it does, consult factory.
SECTION VI
2. Allow suffi cient time for the line pressure down-
stream of the inlet block valve to bleed down.
IOM-CA4/SA4
3. Shutoff the outlet block valve.
4. Relieve the trapped upstream and down stream
pres sure and loading pres sure.
VII. MAINTENANCE
5. The regulator may now be disassembled for
inspection and pre ven ta tive main te nance while
in-line.
SECTION VII
A. General:
WARNING
SYSTEM UNDER PRESSURE. Prior to per form ing
any maintenance, isolate the reg u la tor from the
sys tem and relieve all pressure. Failure to do so
could result in personal injury.
1. The regulator may be serviced without re mov ing the regulator from pipeline. The reg u la tor
is designed with quick-change trim to simplify
maintenance.
2. Record the nameplate information to req ui si tion spare parts for the regulator. The in for ma tion should include: Size, Product Code,
and Serial Number.
3. Refer to Section IX for recommended spare
parts. Only use original equipment parts sup plied by Cashco/KM for re build ing or re pair ing
regulators.
4. Owner should refer to owner's procedures for
removal, handling, cleaning and disposal of
nonreuseable parts, i.e. seals, etc.
27
13
19
15
*
27.3
*
16
20
Type UC - U-Cup
Dynamic Seal
*
13
19
15
*
27.1
*
27.2
*
16
20
Type CP - Cap
Dynamic Seal
5. The Inner Trim is re moved and replaced in the
body (23) as an assemblage of parts. The
Inner Trim Assembly, here in af ter called ITA,
consists of the fol low ing parts:
Item Dynamic
No. Seal Type Part Description
13 ..................... All ..........................Piston-Guide Bearing
15 .....................All ................................ Cage O-ring Seal
16..................... UC.................................................Shim
19 ..................... All ................................................... Cage
20 ..................... All ...........................................Valve Plug
21 ..................... All ............................................ Seat Ring
27 .....................All ............................. Dynamic Side Seal
27.1 .............. CP............................................. Cap Seal
27.2 .............. CP..........................O-ring Energizer/Seal
27.3 .............. UC .......... U-Cup Seal w/Metal Energizer
6. A detailed view of the dynamic side seal parts
is shown in Figure 1; an assembled ITA in
Figure 2; and a cross-sectional drawing of
the entire regulator is shown in Figure 3.
IOM-CA4/SA4
Figure 1: Dynamic Side Seals
B. Main Regulator Disassembly:
1. Shut down system in accordance Section VI.
2. Disconnect loading pressure supply line from
loading chamber. Loosen the diaphragm
fl ange bolts (12) and nuts (11) uniformly.
Remove all bolting and nuts.
3. Place matchmarks on body (23) and loading
chamber (4) fl anges. Remove the loading
cham ber by lifting vertically. NOTE: Seal (28)
may fall out of loading chamber recess.
4. Remove diaphragm(s) (9) and examine to
de ter mine if failed. If diaphragms failed, de ter mine if op er at ing con di tions are ex ceed ing
designed pressure or tem per a ture limits.
5. Evenly loosen the three cage cap screws (18)
3
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 pistonguide 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.
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.
Figure 2: Assembled ITA, with
"UC" Dynamic Side Seal
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.
16
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);
D. Inspection of Parts:
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).
4
IOM-CA4/SA4
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