cashco 123-1+6+S Installation, Operation & Maintenance Manual

ISO Registered Company
MODEL 123-1+6+S DIFFERENTIAL
I. DESCRIPTION AND SCOPE
The Model 123-1+6+S Differential is designed for high pressure liquid or gas applications to Cashco drawing nos.
32934 (NACE construction) and 32935 (Non-NACE construction). It is used to control differential upstream (inlet or
P ) pressure and a loading (P
1
25, and 40).
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. NOT FOR STEAM SERVICE. NOT FOR OXYGEN SERVICE.
II. INSTALLATION
This unit was designed and is used almost exclusively on compressor and turbo expander seal systems. REFER
TO COM PRES SOR/EXPANDER MANUFACTURER'S MANUAL FOR DE TAILED INSTALLATION, START-UP
AND SHUTDOWN OF THIS UNIT. Install regulator with Inlet (P
in accordance with the directional flow arrow cast on body (1).
IIl. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations reg is ter
on the diaphragm (3). The registering pressure is
the inlet (P ) or upstream pressure which reg is ters
1
on the "un der neath" side of the diaphragm (3). The
second pressure registered is the loading (P
pressure in the spring chamber (2) "above" the
diaphragm (3). The range spring (18) determines
the differential pres sure setpoint (P
∆ P = P - P
SIZING 1 2
P > P
1 LOAD
P = P + P
1 LOAD SET
∆ P = P - P
DIFFERENTIAL 1 LOAD
INLET
@ P
1
OUTLET @ P
Model 123-1+6+S Differential Schematic
INSTALLATION, OPERATION & MAIN TE NANCE MANUAL (IOM)
BACK PRESSURE / RELIEF REGULATOR
) pressure to a rotating shaft seal. Sizes are 1/2", 3/4", 1", and 1-1/2" (DN15, 20,
Load
). As inlet
SET
RANGE SPRING:
SETTING @ P
SET
LOADING FLUID
@ P
LOAD
DIA PHRAGM
(Optional)
INLET
@ P
1
2
SECTION I
CAUTION
SECTION II
) pressure coming in the side body (1) connection
1
SECTION III
(P ) pressure drops, the range spring (18) pushes
1
the diaphragm (3) down, clos ing the port; as
inlet (P
pushes up and the port opens. As the loading
(P
LOAD
tends to follow. An increase in (P
inlet (P
)
a decrease in (P
LOAD
pres sure.
2. A complete diaphragm (3) failure will cause the
fluids to mix in the spring chamber (2) or loading
pressure piping. Reg u la tor action will "fail close"
under a di a phragm (3) failure.
3. Under normal operating conditions, the inlet (P
pressure should be greater than the loading
(P
LOAD
setpoint.
Limit any field hydrostatic test to 1-1/2 times the
Maximum Pressure Rat ing (See Ta ble 1). En sure
that the test pressure is applied uniformly to the
body inlet, body outlet, and spring chamber.
) pressure increases, the diaphragm (3)
1
) pressure varies, the inlet (P
) pressure by nearly an equal amount ;
1
) will decrease the inlet (P
LOAD
) pressure by the range spring (P
CAUTION
IOM-123 1+6+S
DIFF
02-16
) pressure
1
) will increase
LOAD
)
1
)
1
)
SET