< 4. Piping >
4-13
IM 11M12D01-01E
4.2.7 Piping to Introduce Purge Gas When a Process Gas Alarm Occurs
When a process gas alarm (an input contact signal of unburnt gas detection) occurs, the averaging
converter will cut off the power supply to the heater of the detector, and at the same time it will send a
contact output to activate a solenoid valve for introducing a purge gas to the detector.
The piping for purging in a system to perform automatic calibration is the same as the one in the
system using flow setting units for manual calibration. As instructed in Subsection 4.1.7, this piping
also requires that a check valve be installed on the calibration gas inlet of the detector. A typical piping
diagram for purging is shown in Figure 4.13.
It is recommended that each instrument be installed to allow for minimum piping between the solenoid
valve for introducing the calibration gases and the check valve, and between the solenoid valve for
introducing the purge gas and the check valve.
To reference gas flow setting
flowmeter and needle valve.
Check valve
Check valve
Calibration
gas line
Reference
gas line
To calibration gas flow setting
needle valve and flowmeter.
To reference gas flow setting
flowmeter and needle valve.
To calibration gas flow setting
needle valve and flowmeter.
Averaging converter (AV550G)
Heater
Signal
Contact
output
Purge gas cylinder
Flowmeter
Pressure reducing
valve
Needle valve
Reference gas line
Calibration
gas line
Solenoid valve
Solenoid valve
Detector
Power supply
Contact input
Contact output
Analog output
(Averaged and
individual outputs)
Stop valve
* : If optional 24 V outputs are specified for solenoid valve (MS Code "/24"), no external power supply for solenoid valves is required.
The solenoid valves are powered from the AV550G Averaging Converter. Never connect external power sources in the wiring for
solenoid valves.
*
*
F4-13E.ai
Calibration
contact outputs
Figure 4.13 Typical Piping for Purging
Содержание av550g
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