Chamber-less smoke sensor

Patent metadata

Field	Value
Publication number	US-9652958-B2
Application number	US-201514743350-A
Country	US
Kind code	B2
Filing date	Jun 18, 2015
Priority date	Jun 19, 2014
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A method for detecting smoke via a chamber-less smoke sensor includes applying one or more filters to eliminate a flooding of ambient light upon the smoke sensor and emitting, by a source, light. At least one detector detects at least a portion of the emitted light and a processor processes the detected light to signal an alarm condition when one or more threshold levels are reached. A chamber-less smoke sensor includes a light source configured to emit light and at least one detector configured to detect at least a portion of the emitted light. An electronic filter and/or a processor is configured to apply one or more filters to eliminate a flooding of ambient light upon the smoke sensor and process the detected light to signal an alarm condition when a threshold level is reached.

First claim

What is claimed is:

1. A method for detecting smoke via a chamber-less smoke sensor, comprising:
applying, one or more filters to eliminate a flooding of ambient light upon the smoke sensor;
emitting, by a source, light;
detecting, by at least one detector, at least a portion of the emitted light; and

processing, by a processor, the detected light to signal an alarm condition when one or more threshold levels are reached;
wherein the emitted light comprises a plurality of different wavelengths; and
wherein the detected light comprises the emitted light obscured by one or more particles located in the smoke sensor, and wherein the threshold level is based on a difference in the detected light as a function of the plurality of different wavelengths.

2. The method of claim 1 , wherein a first of the wavelengths comprises a first wavelength in an optical spectrum, and wherein a second of the wavelengths comprises a second wavelength in the optical spectrum.

3. The method of claim 1 , wherein the detected light comprises scattered light that is scattered by one or more particles located in the smoke sensor, and wherein the threshold levels are based on a difference or a ratio of scattered light associated with a first of the wavelengths and scattered light associated with a second of the wavelengths.

4. The method of claim 3 , wherein the processing of the detected light comprises obtaining a distribution of the one or more particles in terms of a size of the one or more particles.

5. The method claim 1 , further comprising:
providing an offset adjustment to account for a sensitivity of the at least one detector to light of the different wavelengths.

6. The method of claim 1 , further comprising:
coupling a first filter to the source to obtain a reference electrical field orientation for at least one field associated with the light emitted by the source; and
coupling a second filter to at least one detector to detect change in a distribution of electrical field orientations of the at least one field relative to the reference electrical field orientation.

7. The method of claim 1 , further comprising:
coupling a mechanical baffle to the at least one detector to prevent stray light within the smoke sensor from reaching at least one detector.

8. A chamber-less smoke sensor comprising:
a light source configured to emit light;
at least one detector configured to detect at least a portion of the emitted light; and
an electronic filter and/or a processor configured to:
apply one or more filters to eliminate a flooding of ambient light upon the smoke sensor; and
process the detected light to signal an alarm condition when a threshold level is reached;

wherein the emitted light comprises a plurality of different wavelengths; and
wherein the detected light comprises the emitted light obscured by one or more particles located in the smoke sensor, and wherein the threshold levels are based on a difference in the detected light as a function of the plurality of different wavelengths.

9. The smoke sensor of claim 8 , wherein a first of the wavelengths comprises a first wavelength in an optical spectrum, and wherein a second of the wavelengths comprises a second wavelength in the optical spectrum.

10. The smoke sensor of claim 8 , wherein the detected light comprises scattered light that is scattered by one or more particles located in the smoke sensor, and wherein the threshold level is based on a difference or a ratio of scattered light associated with a first of the wavelengths and scattered light associated with a second of the wavelengths.

11. The smoke sensor of claim 10 , wherein the processor is configured to obtain a distribution of the one or more particles in terms of a size of the one or more particles based on the processing of the detected light.

12. The smoke sensor of claim 8 , wherein the processor is configured to provide an offset adjustment to account for a sensitivity of at least one detector to light of the different wavelengths.

13. The smoke sensor of claim 8 , further comprising:
a mechanical baffle coupled to the at least one detector to prevent stray light within the smoke sensor from reaching the at least one detector.

14. A smoke sensor, comprising:
a light source configured to emit light;
at least one detector configured to detect at least a portion of the emitted light;
an electronic filter and/or a processor configured to:
apply one or more filters to eliminate a flooding of ambient light upon the smoke sensor; and
process the detected light to signal an alarm condition when a threshold level is reached;

a first polarizer coupled to the light source, wherein the first polarizer is configured to obtain a reference electrical field orientation for at least one field associated with the light emitted by the source; and
a second polarizer coupled to the at least one detector, wherein the second polarizer and the at least one detector are configured to detect a change in a distribution of orientations of the at least one electrical field relative to the reference orientation,
wherein the threshold level is based on the distribution of electrical field orientations.

Assignees

• Carrier Corp

Inventors

• Zribi Anis
• Silver Travis
• Fasen Ken
• Santistevan Anthony Joseph
• Ratzlaff Larry R
• Miagkov Valeriy
• Burnette Stanley D
• Patel Vipul
• Murphy Jr Charles Edmund

Classifications

• G08B17/107 Primary

  for detecting light-scattering due to smoke · CPC title