Azbil AUR450C, Руководство пользователя

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3-10
Chapter 3. OPERATION
„
Example of instrumentation for the Model AUR450C with an intermittent pilot
Air pressure lower limit
interlock
Gas pressure lower limit
interlock
Gas pressure upper limit
interlock
Ignition
transformer
Air
Gas
MV1 MV2
PV1 PV2
T/C T/C
L
L
H
UV
Controller
Overtemperature limit Vibration
detection limit
Combustion
chamber
Combustion
equipment
Exhaust damper
interlock
Flue
duct
B.C. (AUR450C)
for main burner
B.C. (AUR450C)
for pilot burner
PS
PS
IG
PS
TIC
TIA
UV flame detector
for pilot burner
Exhaust
gas
Vibration
detector
Limit/Interlock
UV flame
detector
for main burner
„
Precautions for instrumentation and circuit configuration with an intermittent pilot
A fundamental rule for intermittent pilots is that a separate monitoring system
is required for the pilot and main burners.
In instrumentation and circuit configuration of the device with an intermittent pilot
valve, note the following:
•
For safety control and operation circuits, devise a safety plan based on risk
assessment.
•
Install separate combustion monitoring equipment (flame detector and burner
controller) for the main burner and pilot burner.
•
Install the flame detector for the main burner in a location where it does not de-
tect the pilot burner flame.
•
Be sure to connect the limit contacts and interlock contacts to the interlock input
terminals of the burner controllers for both the pilot and main burners in such
a way that the circuit can directly disconnect loads (ignition transformer, pilot
safety shutoff valves, main safety shutoff valves, etc.).
•
When configuring the start circuit, be sure to connect the pilot ignition signal
output from the burner controller for the pilot burner to the interlock input ter-
minal and start input terminal on the burner controller for the main burner.
•
Design a circuit that shuts down all the burners when a ignition failure or a flame
failure of the pilot or main burner occurs.
•
Install all the interrupt contacts on the high potential (non-ground) side of the
power supply. As needed, take preventive measures against electrical leakage,
such as using an electrical leakage breaker or a double pole contact system.
•
Do not configure a circuit that turns off the interlock input (terminals 17–18)
using the alarm output contacts (terminals 11–12). With such a circuit, if a false
flame, UV alarm, ignition failure, or flame failure occurs, the interlock alarm may
be displayed.