The sensing part of the detector consists of two chambers - an open outer chamber and a semi-sealed reference chamber within. Mounted in the reference chamber is a low activity radioactive foil of Americium 241 which enables current to flow between the inner and outer chambers when the detector is powered up.

 

As smoke enters the detector, it causes a reduction of the current flow in the outer chamber and hence an increase in voltage measured at the junction between the two chambers. The voltage increase is monitored by the electronic circuitry which triggers the detector into the alarm state at a preset threshold. An externally visible red LED lights up when in alarm. IP rating = IP23D

 

   

ADVANTAGES

  • Features: Flashing LED; Alarm indication: Red LED; Supply voltage: 9 to 33V

  • Average stand-by current at 24V: 45uA; Average stand-by current at 9V: 21uA

  • Alarm current at 24V: 52mA; Alarm current at 9V: 17mA

  • Ambient temperature: 32 to 158°F; Max wind continuous: 2,000ft/min

  • Remote output (R-) characteristics: Current sink to -ve line, limited to 17mA. Note: when using a remote indicator a current-limiting series resistor may be required.