Importance

Loading Importance Indicators...

Abstract

An optical fire detection system that uses cosmic radiation or a radioactive source to test whether the ultraviolet light detector tube operates properly and includes self test logic to independently verify that the detector electronics are functioning properly. A high voltage is applied across the ultraviolet light detector tube to produce pulses of current when radiation is present. A pulse rate discriminator circuit measures the current pulses and outputs a fire signal if the pulse rate is equal to or greater than the pulse rate produced by ultraviolet radiation from a fire. A background count circuit also measures the current pulses from the ultraviolet light detector tube to test whether the ultraviolet light detector tube is operational. At least one current pulse should be detected within a specified time because the detector tube senses cosmic radiation or radiation from the radioactive source. If no current pulse is received by the background detector circuit within the specified time, the background count circuit signals that the detector tube or high voltage supply is defective.

Loading the Abstract Image...

First Claim