Cashco 123-1+6+S - Manual

IIl. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations reg is ter
on the diaphragm (3). The registering pressure is
the inlet (P
1
) or upstream pressure which reg is ters
on the "un der neath" side of the diaphragm (3).
The second pressure registered is the loading
(P
LOAD
) pressure in the spring chamber (2) "above"
the diaphragm (3). The range spring (18) deter-
mines the differential pres sure setpoint (P
SET
). As
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
1
) pressure and a loading (P
Load
) pressure to a rotating shaft seal. Sizes are 1/2", 3/4", 1", and 1-1/2" (DN15, 20,
25, and 40).
SECTION III
IOM-123 1+6+S
DIFF
12-13
MODEL 123-1+6+S DIFFERENTIAL
BACK PRESSURE / RELIEF REGULATOR
INSTALLATION, OPERATION & MAIN TE NANCE MANUAL (IOM)
SECTION I
SECTION II
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
1
) pressure coming in the side body (1) connection
in accordance with the directional fl ow arrow cast on body (1).
∆ P
SIZING
= P
1
- P
2
P
1
> P
LOAD
P
1
= P
LOAD
+ P
SET
∆ P
DIFFERENTIAL
= P
1
- P
LOAD
LOADING FLUID
@ P
LOAD
DIA PHRAGM
RANGE SPRING:
SETTING @ P
SET
(Optional)
INLET
@ P
1
OUTLET @ P
2
Model 123-1+6+S Differential Schematic
inlet (P
1
) pressure drops, the range spring (18)
pushes the diaphragm (3) down, clos ing the port;
as inlet (P
1
) pressure increases, the diaphragm
(3) pushes up and the port opens. As the load-
ing (P
LOAD
) pressure varies, the inlet (P
1
) pressure
tends to follow. An increase in (P
LOAD
) will increase
inlet (P
1
) pressure by nearly an equal amount ;
a decrease in (P
LOAD
) will decrease the inlet (P
1
)
pres sure.
2. A complete diaphragm (3) failure will cause the
fl uids 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
1
)
pressure should be greater than the loading
(P
LOAD
) pressure by the range spring (P
SET
) set-
point.
INLET
@ P
1
Limit any fi eld 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.
CAUTION B
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.
CAUTION A