Case Study: Zone 1/21 Exhaust Control System
Extronics received an enquiry to build a Zone 1/21 exhaust control system installed in a weighbridge pit, utilising two redundant supplies and dual control circuits.
The request to Extronics was to control 2 exhaust fans, duty and standby, which would keep the weighbridge pit clear of Hazardous atmosphere.
The control panel was to be fed from 2 different supplies and the main objective was to keep the area clear in the event of any or all of the following fault conditions:-
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- Failure/ Shutdown of either incoming power supply
- Failure/ Shutdown of either duty or stand-by fan
- Failure/ Shutdown of either control circuit transformer
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Extronics designed the control circuit that if any or all of the above occurred then the appropriate backup would automatically start and sound an alarm and/ or show a remote indicator, maintaining airflow through the hazardous area.
The finished Control Panel was Zone 1/ 21 ATEX certified for use in a IIB +H2 gas group area and was delivered to the customer complete with wiring schematics.
