Danger detector with a non-contact heat radiation sensor for establishing an ambient temperature

• US 9,858,786 B2
• Filed: 02/10/2014
• Issued: 01/02/2018
• Est. Priority Date: 03/06/2013
• Status: Active Grant

• Current Assignee: Siemens Schweiz AG (Siemens AG)
• Original Assignee: Siemens Schweiz AG (Siemens AG)
• Inventors: Fischer, Martin, Foelmli, Claudio, Liechti, Christian
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Maupin, Hugh H
• Application Number:
  US14/768,129
• Publication Number:
  US 20150379847A1
• Time in Patent Office: 1,422 Days
• CPC Class Codes: G01J 5/0014 for sensing the radiation from gases, flames
• CPC Class Codes: G01J 5/025 Interfacing a pyrometer to an external device or network; User interface
• CPC Class Codes: G01J 5/041 Mountings in enclosures or in a particular environment
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors
• CPC Class Codes: G01J 5/0821 Optical fibres
• CPC Class Codes: G01J 5/0887 Integrating cavities mimicking black bodies, wherein the heat propagation between the black body and the measuring element does not occur within a solid; Use of bodies placed inside the fluid stream for measurement of the temperature of gases; Use of the reemission from a surface, e.g. reflective surface; Emissivity enhancement by multiple reflections
• CPC Class Codes: G01J 5/12 using thermoelectric elements, e.g. thermocouples
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: G01J 5/58 using absorption; using extinction effect
• CPC Class Codes: G01J 5/602 using selective, monochromatic or bandpass filtering
• CPC Class Codes: G08B 17/12 Actuation by presence of radiation or particles, e.g. of infrared radiation or of ions

Abstract

A danger detector configured as a point detector includes an alarm housing with an alarm cover, a non-contact heat radiation sensor that is sensitive to heat radiation in the infrared range, and a treatment unit configured to determine and emit a temperature value derived from the detected heat radiation for the ambient temperature in the surroundings of the danger detector and/or an alarm, in the event that the currently determined temperature value exceeds a predetermined temperature comparison value. The heat radiation sensor is arranged in the alarm housing and is configured to optically detect the ambient temperature on the inner side of the alarm cover. The heat radiation sensor may be a thermopile designed as an SMD component.

Claims

1. A danger detector embodied as a point-type detector, the danger detector comprising:

an alarm housing with an alarm cover having a light-impermeable opaque area configured to receive environmental heat radiation via an open air ambient environment outside of the alarm cover and emit heat radiation from an inner side of the light-impermeable opaque area of the alarm cover as a function of heating of the alarm cover by the environmental heat radiation,

a non-contact heat radiation sensor disposed in the alarm housing and aligned optically with the inner side of the light-impermeable opaque area of the alarm cover, and configured to generate a sensor signal corresponding to heat radiation in the infrared range emitted by the inner side of the light-impermeable opaque area as a function of the heating of the alarm cover by the environmental heat radiation of the ambient environment outside the alarm cover,

a processing unit, and

computer instructions stored in non-transitory memory and executable by the processing unit to;

determine an ambient temperature value for an ambient temperature in the open air environment outside the alarm housing of the danger detector based on the sensor signal generated by the non-contact heat radiation sensor, and

based on the determined ambient temperature value, visibly or audibly output at least one of;

the determined ambient temperature value, or

an alarm message in response to the determined ambient temperature value exceeding a predetermined temperature comparison value.

2. The danger detector of claim 1, wherein the inner side of the alarm cover is configured as a measurement surface for non-contact acquisition of the heat radiation and wherein the measurement surface lies optically in an acquisition area of the heat radiation sensor.

3. The danger detector of claim 2, wherein the measurement surface is located at a central position of the alarm cover to provide largely direction-independent acquisition of the ambient temperature.

4. The danger detector of claim 2, wherein the measurement surface of the alarm cover comprises at least one of (a) a treated or untreated material with a predetermined surface property or (b) a material with a coating with a degree of emission for heat radiation in an infrared range of the measurement surface of at least 0.75.

5. The danger detector of claim 4, wherein the computer instructions are executable by the processing unit to determine the ambient temperature value based on the sensor signal generated by the heat radiation sensor and a stored value for the degree of emission of the measurement surface.

6. The danger detector of claim 1, wherein the danger detector comprises two non-contact heat radiation sensors sensitive for heat radiation in the infrared range, wherein the two heat radiation sensors have different spectral heat radiation sensitivities, and wherein the processing unit is configured to determine the ambient temperature value based on a ratio pyrometry.

7. The danger detector of claim 1, wherein:

the danger detector comprises one non-contact heat radiation sensor sensitive for heat radiation in the infrared range,

a switchable optical filter for two different spectral heat radiation sensitivities is connected upstream of the heat radiation sensor, and

the processing unit is configured to determine the ambient temperature value based on a ratio pyrometry.

8. The danger detector of claim 1, wherein the heat radiation sensor and the processing unit are combined into a single component as a non-contact temperature sensor.

9. The danger detector of claim 2 wherein an alarm cover part corresponding to the measurement surface has a reduced thickness as compared with a remaining part of the alarm cover.

10. The danger detector of claim 1, wherein:

the respective heat radiation sensor has a heat radiation-sensitive sensor surface,

at least one of an optical lens or an optical fiber is disposed between the sensor surface and the inner side of the alarm cover, and

the lens and the optical fiber are transparent for light in a mid-infrared range.

11. The danger detector of claim 1, wherein the heat radiation sensor comprises a thermopile or a bolometer.

12. The danger detector of claim 1, comprising a gas sensor for fire flue gases arranged in the danger detector,

wherein the alarm housing comprises at least one entry opening for fire flue gases.

13. The danger detector of claim 1, comprising a scattered light arrangement disposed in or on the alarm housing for detection of smoke particles.

14. The danger detector of claim 1, wherein:

the non-contact heat radiation sensor comprises a thermopile or bolometer that is sensitive for a mid-range of infrared radiation from 3 μ

m to 20 μ

m; and

a region of the alarm cover opposing the thermopile or bolometer is permeable only for the mid-range of infrared radiation from 3 μ

m to 20 μ

m.

15. A method for determining a temperature value in an open air environment outside an alarm cover of a danger detector embodied as a point-type detector, the method comprising:

receiving, at a light-impermeable opaque area of the alarm cover, environmental heat radiation of an ambient environment outside the alarm cover,

emitting heat radiation by an inner side of the light-impermeable opaque area of the alarm cover as a function of heating of the alarm cover by the environmental heat radiation,

generating, by a non-contact heat radiation sensor, a sensor signal indicating a detected heat radiation emitted by the inner side of the light-impermeable opaque area of the alarm cover,

determining the temperature value for the environment of the danger detector based at least on;

(a) the generated sensor signal, and

(b) a degree of emission for the heat radiation based on at least one of the material of the of the light-impermeable opaque area of the alarm cover or a surface property of the inner side of the light-impermeable opaque area of the alarm cover, and

visibly or audibly outputting at least one of the determined temperature value or a signal indicative of the determined temperature value.

16. The method of claim 15, wherein the non-contact heat radiation sensor comprises a thermopile or a bolometer.

17. A method for determining an ambient temperature value for an open air environment outside an alarm cover of a danger detector embodied as a point-type detector, the method comprising:

emitting heat radiation by an opaque inner side of an alarm cover as a function of heating of the alarm cover by environmental heat radiation of an ambient environment outside of the alarm cover,

generating, by each of two heat radiation sensors, a respective sensor signal indicating a detected heat radiation emitted by the opaque inner side of the alarm cover as a function of the heating of the alarm cover by the environmental heat radiation of the ambient environment outside of the alarm cover,

wherein the two heat radiation sensors have different spectral heat radiation sensitivities, and

determining the ambient temperature value for the environment of the danger detector via a ratio pyrometry of the two sensor signals, and

visibly or audibly outputting at least one of the determined ambient temperature value or a signal indicative of the determined ambient temperature value.

18. The method of claim 17, wherein each of the heat radiation sensors comprises either a thermopile or a bolometer.

19. The method of claim 17, wherein each of the two heat radiation sensors is configured to detect heat radiation emitted from the opaque area of the inner side of the alarm cover.