US 11,698,340 B2
Fire detection apparatus
Manabu Dohi, Shinagawa-ku (JP); Tomohiko Shimadzu, Shinagawa-ku (JP); and Keisuke Washizu, Shinagawa-ku (JP)
Assigned to Hochiki Corporation, Tokyo (JP)
Filed by HOCHIKI Corporation, Shinagawa-ku (JP)
Filed on Sep. 26, 2020, as Appl. No. 17/33,721.
Application 17/033,721 is a continuation in part of application No. PCT/JP2019/012774, filed on Mar. 26, 2019.
Claims priority of application No. 2018-062683 (JP), filed on Mar. 28, 2018.
Prior Publication US 2021/0088442 A1, Mar. 25, 2021
Int. Cl. G01N 21/53 (2006.01)
CPC G01N 21/53 (2013.01) 7 Claims
OG exemplary drawing
 
1. A fire detection apparatus for detecting and reporting a fire in a monitored area, the fire detection apparatus comprising:
a substrate including,
a first light emitting unit configured to irradiate a detection space located inside or outside the fire detection apparatus with a first detection light, the first light emitting unit having at least one light emitting element that is a light emitting diode;
a second light emitting unit configured to irradiate the detection space with a second detection light having a different wavelength from a wavelength of the first detection light, the second light emitting unit having at least one light emitting element that is a light emitting diode;
a light receiving unit configured to receive scattered light of the first detection light irradiated from the first light emitting unit due to smoke, to output a first light receiving signal according to the received scattered light, to receive scattered light of the second detection light irradiated from the second light emitting unit with respect to smoke, and to output a second light receiving signal according to the received scattered light, the light receiving unit having at least one light receiving element that is a photodiode;
a memory storing program instructions, and
a processor,
wherein the program instructions are executable by the processor to configure an identification unit that is configured to identify a type of smoke present in the detection space,
wherein the type of smoke is set for each of a plurality of ranges identified by a correspondence between a first large/small relationship and a second large/small relationship,
the first large/small relationship is a relationship between an output ratio of an output value of the first light-receiving signal to an output value of the second light-receiving signal output from the light receiving unit and a plurality of first threshold values,
the second large/small relationship is a relationship between a rising rate of the output value of the first light-receiving signal or the second light-receiving signal and a plurality of second threshold values which are different from the plurality of the first threshold values,
the identification unit is configured to identify 1) the first large/small relationship between the output ratio and the plurality of the first threshold values, 2) the second large/small relationship between the rising rate and the plurality of the second threshold values, 3) a range of the plurality of ranges based on the correspondence between the identified first large/small relationship and the identified second large/small relationship, and 4) the type of smoke corresponding to the identified range of the plurality of ranges, and
wherein the rising rate is either one of
(an output value of most recently acquired first light receiving signal)/(output value of first light receiving signal acquired first)−1, or
(an output value of most recently acquired second light receiving signal)/(output value of second light receiving signal acquired first)−1.