Patent ID: 9513007
Filing Date: 2016-12-06
CPC Classification: A62C,F23N,G08B

Claim Text:
1. An electrical isolation device for isolating the electrical supply of a fuel burning appliance in response to an audio alarm, the device comprising: a microphone circuit operable to detect audio signals; a lock-in amplifier connected to an output of the microphone circuit and operable to lock on to an alarm frequency and recover a modulated signal pattern of a potential alarm signal within the audio signals detected by the microphone circuit; a processing unit operable to monitor an output of the lock-in amplifier for valid output signals through comparison of the potential alarm signal with a stored reference to determine whether the potential alarm signal is an alarm signal and output an alarm indication in response thereto; and a switch operable in response to said alarm indication to disconnect the electrical supply of the fuel burning apparatus.