Emerson Fisher 310A-32A-32A Instruction Manual page 4

Type 310A
E0385
InLET PRESSuRE
OuTLET PRESSuRE
ATMOSPhERIC PRESSuRE
LOADIng PRESSuRE
InTERMEDIATE PRESSuRE
PILOT SuPPLY PRESSuRE
Figure 3. Type 310A-32A-32A Working Monitor Regulator Operational Schematic
Monitor Systems
Wide-Open Monitors (Figure 4)
Monitoring regulators serve as overpressure protection
devices to limit system pressure in the event of failure
of working regulators feeding the system. The control
line of a wide-open monitoring regulator may be
connected downstream of the working regulator, so
that during normal operation the wide-open monitoring
regulator is standing wide-open with the pressure
reduction being taken across the working regulator.
Only in case of working regulator failure does the
wide-open monitoring regulator function.
4
PLug
SPACER
PLug
WORKIng PILOT
RESTRICTIOn
MOnITORIng PILOT
Working Monitors (Figure 5)
The Type 310A-32A-32A differs from wide-open
monitors in that it has working monitor capability. This
means that it normally reduces pressure and throttles
while the second-stage regulator is in operation.
Should the second-stage working regulator fail open,
the Type 310A-32A-32A will take over the entire
pressure reduction function.
The working monitor pilots are adaptations of two
Type 32A pilots with special internal parts, due to the
pressure conditions in this piloting system. A spacer
blocks open the differential regulator portion of the
Type 32A monitoring pilot. A plug in both the working
and monitoring pilots makes the internal bleed non-