Cashco 123 User Manual
INSTALLATION, OPERATION & MAIN TE NANCE MANUAL (IOM)
IOM-123-BASIC
MODEL 123 — BASIC
BACK PRESSURE / RELIEF REGULATOR
SECTION I
I. DESCRIPTION AND SCOPE
The Model 123 is a back pressure relief regulator used to control upstream (inlet or P1) pressure. Sizes are 1/2",
3/4", 1", 1-1/2" and 2" (DN15, 20, 25, 40 and 50). With proper trim utilization, the unit is suitable for liquid, gaseous,
or steam service. Refer to Technical Bulletin 123-TB for design conditions and se lec tion recommendations.
CAUTION A
This is not a safety device and must not be sub sti tut ed for a code approved
pres sure safety relief valve or rupture disc.
SECTION II
12-13
II. INSTALLATION
CAUTION B
For welded installations, all internal trim parts, seals
and diaphragm(s) must be removed from reg u la tor
body prior to welding into pipeline. The heat of
fusion welding will dam age non-metallic parts if
not re moved. NOTE: This does not apply to units
equipped with extended pipe nip ples.
1. An inlet block valve should always be in stalled.
2. If service application is continuous such that
shut down is not readily accomplished, it is rec om mended that an inlet block valve, outlet block
valve, and a manual bypass valve be in stalled.
3. Pipe unions should be installed to allow removal
from piping.
4. An inlet pressure gauge should be lo cated ap proxi mately ten pipe diameters upstream and within
sight. An outlet pres sure gauge is optional.
5. All installations should include an upstream relief
de vice if the inlet pressure could exceed the pressure rating of any equipment or the maximum inlet
pressure rating of the unit.
CAUTION C
Supply @ P
P
1
System
Demand
SRV
1
Discharge
Model 123-33
BP/Relief
Regulator
P
2
Bypass
Recommended Piping Schematic for
Back Pressure/Relief Station
6. Clean the piping of all foreign material in clud ing
chips, welding scale, oil, grease and dirt before in stall ing the valve. Strain ers are rec om mended.
7. In placing thread sealant on pipe ends prior to
en gage ment, ensure that excess material is re moved and not allowed to enter the regulator upon
startup.
8. Flow Direction: Install so the fl ow direction match-
es the arrow cast on the body. The body has an
angle con fi g u ra tion with a side inlet and bottom
outlet.
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.
9. Regulator may be installed in a vertical or hor i zon tal pipe. If it is a steam system, ensure the
piping is properly trapped and oriented.
10.A. Basic Regulator- (See Figure 1): Regulator may be
rotated around the pipe axis 360°. Rec om mend ed
po si tions are with spring cham ber ver ti cal upwards,
or hori zon tal. Orient such that the spring chamber
vent hole does not collect rain wa ter or debris.
10.B. Cryogenic Regulator -
Option-5 or -36 (See Fig ure 2):
a. Recommended installation is with spring cham-
ber hang ing vertical downward below the body.
This method allows water to drain; i.e. rain water.
b. Recommend inert purge gas to spring cham ber
through vent hole and out drain hole.
III. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations reg is ter on
the diaphragm. The registering pressure is the inlet,
P
or upstream pressure. The range spring opposes
1
dia phragm move ment. As inlet pressure drops, the
WARNING 1
The maximum inlet pressure is equal to 1.5 times the
larger number of the stated range spring on the name plate, and is the recommended “upper operative limit” for
the sensing diaphragm. Higher pressures could dam age
the diaphragm. (Field hydro static tests fre quent ly de stroy
diaphragms. DO NOT HYDRO STATIC TEST THROUGH AN
IN STALLED UNIT; ISO LATE FROM TEST.)
11. Regulators are not to be direct buried un der ground.
12. For insulated piping systems, rec om men da tion is to
not in su late reg u la tor.
SECTION III
range spring pushes the dia phragm down, closing
the port; as inlet pressure in creases, the dia phragm
pushes up and the port opens.
2. A complete diaphragm failure may cause the regulator to fail closed.
IV. STARTUP
1. Start with the block valves closed. A bypass valve
may be used to maintain inlet pressure in the
up stream system without chang ing the following
steps.
2. Relax the range spring by turning the adjusting
screw counterclockwise (CCW) a minimum of three
(3) full revo lu tions. This reduces the inlet (upstream)
pres sure setpoint.
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. Ensure proper steam trap operation
if in stalled. Closely mon i tor inlet (up stream) pres sure, via gauge, to assure not over-pres sur iz ing.
NOTE: If no bypass valve is in stalled, extra caution
should be used in starting up a cold system; i.e. do
ev ery thing slowly.
4. Crack open the inlet (upstream) block valve.
5. Slowly open the outlet (downstream) block valve
ob serv ing the inlet (upstream) pressure gauge. De ter mine if the regulator is fl owing. If not, slowly ro-
tate the regulator adjusting screw counter clock wise
(CCW) until fl ow be gins.
6. Continue to slowly open the outlet (down stream)
block valve until fully open.
SECTION IV
7. Observing the inlet (upstream) pressure gauge,
ro tate the ad just ing screw clockwise (CW) slowly
until the inlet pressure begins to rise. Rotate CW
until the desired setpoint is reached.
8. Continue to slowly open the inlet (upstream) block
valve. If the inlet (upstream) pressure ex ceeds
the desired set point pressure, rotate the adjusting
screw CCW until the pressure decreases.
9. When fl ow is established steady enough that both
the outlet and inlet block valves are fully open, begin
to slowly close the bypass valve if installed.
10. Develop system fl ow to a level near its expected nor-
mal rate, and reset the regu la tor set point by turning
the ad just ing screw CW to increase inlet pressure,
or CCW to reduce inlet pressure.
11. Reduce system fl ow to a minimum level and observe
set point. Inlet pressure will rise from the setpoint
of Step 9. (Ensure that this rise does not exceed
the stated upper limit of the range spring by greater
than 50%, i.e. 30 - 80 psig (2.1 - 5.5 Barg) range
spring, at maximum fl ow the inlet pressure should
not ex ceed 1.5 x 80 psig (5.6 Barg), or 120 psig (8.3
Barg). If it does, consult factory.)
12. Increase fl ow to maximum level if possible. Inlet
(up stream or P
) pressure should fall off. Readjust
1
setpoint as necessary at the normal fl ow rate.
2
IOM-123-BASIC
V. SHUTDOWN
SECTION V
1. On systems with a bypass valve, and where sys tem pres sure is to be maintained as the regu la tor
is shut down, slowly open the bypass valve while
closing the inlet (upstream) block valve. Fully
close the inlet (up stream) block valve. (When on
bypass, the system pressure must be con stant ly
observed and manually reg u lat ed. Close the outlet (down stream) block valve.
SECTION VI
VI. MAINTENANCE
WARNING 2
SYSTEM UN DER PRES SURE. Prior to performing
any maintenance, isolate the reg u la tor from the system and relieve all pressure. Failure to do so could
result in per son al injury.
A. General:
1. Maintenance procedures hereinafter are
based upon removal of the regulator unit from
the pipe line where installed.
CAUTION D
Do not walk away and leave a bypassed reg u la tor
un at tend ed.
2. If the reg u la tor and system are both to be shut down, slowly close the inlet (upstream) block
valve. Close the outlet (downstream) valve only
if regu la tor re moval is required.
6. Remove diaphragm sub-assembly con sist ing
of the diaphragm(s) (3), pressure plate (2),
lock washer (13), piston (14), piston nut (6)
and pusher plate gasket (5). NOTE: Refer to
the quantity of di a phragms (12) in cor po rated
per the bill of ma te ri als listing. De pend ing
on inlet pressure level, mul tiple metal dia phragms may be “stacked”.
7. Loosen the piston nut (6) and separate all
parts (3, 5, 13, 14 & 20) of the diaphragm
sub-assembly. Clean the pusher plate gasket
(5) sur face if the piston (14) is to be reused.
2. Owner should refer to owner's procedures for
re mov al, handling, cleaning and disposal of
non reuseable parts, i.e. gaskets, etc.
3. Refer to Figure 1 for basic regulator, Figure
2 for cryogenic regulator, and Figure 3 for
blow-up of the com po si tion seat trim.
B. Diaphragm Replacement:
WARNING 3
SPRING UNDER COMPRESSION. Prior to re mov ing spring chamber, relieve spring compression
by removing the ad just ing screw. Failure to do so
may result in fl ying parts that could cause personal
injury.
1. Securely install the body (1) in a vise with the
spring chamber (2) directed upwards.
2. Rotate the adjusting screw (17) CCW until
re moved from the spring cham ber (2).
3. Draw or em bed a match mark on the body (1)
and spring chamber (2) fl anges.
4. Remove diaphragm fl ange nuts (8) and bolts
(7).
5. Remove spring chamber (2), range spring
(18) and spring button (19).
8. Inspect pressure plate (20) for de for ma tion
due to over-pressurization. If de formed, re place.
9. Remove diaphragm gasket (4) for metal di a phragm. NOTE: No diaphragm gasket (4) for
com po si tion dia phragm.
10. Clean body (1) and diaphragm fl ange. NOTE:
On reg u la tors originally supplied as “spe cial
cleaned”, Option-5, -36 or -55, main te nance
must in clude a level of clean li ness equal to
Cash co’s cleaning standard #S-1134. Con tact fac to ry for details.
11. For metal dia phragms (3), place the di a phragm gas ket (4) on the body (1) fl ange.
A light coat of gasket sealant is rec om mend ed.
12. Re as sem ble di a phragm sub-as sem bly by
plac ing pis ton (14) in a vise, post upwards,
grasping on the hexagonal surface. Place
the pusher plate gasket (5), diaphragm(s)
(3), pressure plate (20) and lock washer (13)
over the threaded post. Ensure that the pres sure plate (20) is placed with curved outer rim
down next to the dia phragm (3) surface. Place
a thread seal ant com pound on the threads
of the piston (14) post prior to tight
piston nut (6) to the following torque values:
en ing the
IOM-123-BASIC
3
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