CSB400 Series
9
InLET PRESSURE
OUTLET PRESSURE
aTMOSPHERIC PRESSURE
Figure 7.
Type CSB404ET, Externally Registered Regulator and Slam-Shut Operational Schematic
Type CSB400EN Regulator without Relief
MXXXX
May 2008
Type CSB400
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
M1146
PRIMaRY REgULaTOR
TYPE VSX4 SLaM-SHUT MODULE
M1
146
RESET KnOB
VEnT
OPSO SET SPRIng
UPSO SPRIng
UPSO aDjUSTIng SCREW
SEnSE BLOCKIng
SCREW
OPSO aDjUSTIng SCREW
SLaM-SHUT
ORIFICE
REgULaTOR ORIFICE
VaLVE STEM
LEVER
EXTERnaL COnTROL
LInE (SEnSE LInE)
REgULaTOR COnTROL SPRIng
REgULaTOR aDjUSTIng SCREW
TOKEn RELIEF
SPRIng
Principle of Operation
Type CSB400 Base Regulator Operation
Refer to Figure 5. When downstream demand
decreases, the pressure under the regulator
diaphragm increases. This pressure overcomes
the regulator setting (which is set by the regulator
control spring). Through the action of the pusher post
assembly, lever, and valve stem, the valve disk
moves closer to the orifice and reduces gas flow.
If demand downstream increases, pressure under
the regulator diaphragm decreases. Spring force
pushes the pusher post assembly downward, the
valve disk moves away from the orifice, and the gas
flow increases downstream as the regulator opens in
response to the decreased pressure underneath the
regulator diaphragm.
Type numbers with a “T”, for example, Type CSB400IT,
provide a token or low capacity relief. The Token relief
provides relief from minor overpressure caused by
nicks or dents on the orifice or by thermal expansion
of gas in the downstream line. Token relief also
provides a token or signal, in the form of odor, that an
overpressure situation is occurring.
Type CSB403 Integral Monitor Operation
Type CSB403 combines the operation of a
conventional two-regulator wide-open monitor set into
one body, see Figure 6. The Integral True-Monitor™
is installed on the inlet side of the body and serves to
throttle flow and maintain an acceptable downstream
pressure in the case where the primary regulator
ceases to regulate downstream pressure. During
normal operation the Integral Monitor is in a wide-open
state as its setpoint is set higher than the primary
regulator. See Table 6 for guidance regarding the
setpoints of the regulator and associated integral
monitor sets. If the downstream pressure should rise
to the setpoint of the Internal Monitor due to a loss of
pressure control by the primary regulator, the Integral
Monitor will assume control and regulate the flow to
the downstream system. If token relief is present, it
will relieve a small amount of gas to the atmosphere
as an indication that the Integral Monitor is controlling
the downstream pressure.
The Type CSB403 provides the option of internal or
external downstream pressure registration. External
registration requires a downstream sensing line. See
Figure 10 for guidance regarding installation of the
downstream control line. Refer to the Type TM600
Instruction Manual for additional details of integral
monitor operation.
SLaM-SHUT DISK