Receiver, fire detection system, and fire detection method

Patent metadata

Field	Value
Publication number	US-11761891-B2
Application number	US-201917263288-A
Country	US
Kind code	B2
Filing date	Jun 6, 2019
Priority date	Jul 31, 2018
Publication date	Sep 19, 2023
Grant date	Sep 19, 2023

Abstract

A receiver ( 10 ) according to the present disclosure includes: a detection unit ( 11 ) including a sensor configured to receive a first optical signal of a wavelength included in an absorption band of water molecules and a second optical signal of a wavelength included in an absorption band of carbon dioxide molecules, a signal processing unit ( 12 ) configured to calculate a water vapor concentration and a carbon dioxide concentration from changes of intensities of the first and second optical signals, and a determination unit ( 13 ) configured to determine whether or not there is a fire that is caused by alcohol combustion based on the water vapor concentration and the carbon dioxide concentration.

First claim

What is claimed is:

1. A receiver comprising:
at least one memory storing instructions, and
at least one processor configured to execute the instructions to;
receive a first optical signal of a wavelength included in an absorption band of water molecules and a second optical signal of a wavelength included in an absorption band of carbon dioxide molecules;
calculate a water vapor concentration and a carbon dioxide concentration from changes in intensities of the first and second optical signals;
determine whether or not there is a fire that is caused by alcohol combustion based on the water vapor concentration and the carbon dioxide concentration;
receive a third optical signal of a wavelength included in an absorption band of carbon monoxide molecules;
calculate a carbon monoxide concentration from the change in the intensity of the third optical signal and calculates a transmittance of at least one of the first to third optical signals;
determine a sign of a fire based on the carbon monoxide concentration when the calculated transmittance is lower than a predetermined threshold;
receive the first optical signal, the second optical signal, and the third optical signal;
calculate first to third gas concentrations from the respective intensities of the first to third optical signals;
calculate a transmittance from at least one of the intensities of the first to third optical signals; and
determine a progress of a fire based on the first to third gas concentrations and the transmittance.

2. The receiver according to claim 1 , further comprising:
the at least one processor is further configured to execute the instructions to store a feature amount in the event of a fire and a feature amount in the event of a non-fire learned using the first to third gas concentrations and the transmittance as results of learning; and
determine the progress of the fire based on results of performing calculations using patterns of the changes in the first to third gas concentrations and the transmittance and the feature amounts.

3. The receiver according to claim 1 , wherein the at least one processor is further configured to execute the instructions to determine that there is a fire based on the carbon dioxide concentration and the water vapor concentration when the calculated transmittance is higher than a predetermined threshold.

4. A fire detection method executed in a receiver, the fire detection method comprising:
receiving a first optical signal of a wavelength included in an absorption band of water molecules and a second optical signal of a wavelength included in an absorption band of carbon dioxide molecules;
calculating a water vapor concentration and a carbon dioxide concentration from changes in intensities of the first and second optical signals;
determining whether or not there is a fire based on the changes in the water vapor concentration and the carbon dioxide concentration;
receiving a third optical signal of a wavelength included in an absorption band of carbon monoxide molecules;
calculating a carbon monoxide concentration from the change in the intensity of the third optical signal and calculating a transmittance of at least one of the first to third optical signals;
determining a sign of a fire based on a carbon monoxide concentration when the calculated transmittance is lower than a predetermined threshold;
receiving the first to third optical signals;
calculating first to third gas concentrations from the respective intensities of the first to third optical signals;
calculating a transmittance from the intensity of at least one of the first to third optical signals; and
determining a progress of a fire based on the first to third gas concentrations and the transmittance.

5. The fire detection method according to claim 4 , comprising:
storing a feature amount in the event of a fire and a feature amount in the event of a non-fire learned using the first to third gas concentrations and the transmittance as results of learning; and
determining the progress of the fire based on results of performing calculations using patterns of the changes in the first to third gas concentrations and the transmittance and the feature amounts.

Assignees

• Nec Corp

Inventors

• Matsuda Yuma
• Tanaka Akihiro

Classifications

• G01N33/004 Primary

  CO or CO2 · CPC title

• G01N21/534 Primary

  by measuring transmission alone, i.e. determining opacity · CPC title

• G01N33/006

  Avoiding interference of water vapour with the gas to be measured · CPC title

• G08B17/103

  using a light emitting and receiving device · CPC title

• G01N21/31

  Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)} · CPC title