Optical fiber sensor system for detecting temperature changes in an aircraft

• US 10,260,964 B2
• Filed: 06/25/2014
• Issued: 04/16/2019
• Est. Priority Date: 06/25/2014
• Status: Active Grant

• Current Assignee: Saab AB
• Original Assignee: Saab AB
• Inventors: Fisk, Fredrik, Andersson, Bjorn-Erik
• Primary Examiner(s): Jagan, Mirellys
• Application Number:
  US15/322,369
• Publication Number:
  US 20170138802A1
• Time in Patent Office: 1,756 Days
• Field of Search: 374161, 374131, 374141, 374137
• CPC Class Codes: G01K 11/3206 at discrete locations in the fibre, e.g. using Bragg scattering
• CPC Class Codes: G01K 13/00 Thermometers specially adapted for specific purposes

Abstract

The present disclosure relates to an optical fiber sensor system (10) arranged to detect a temperature change in a zone (2, 3, 4) in an aircraft (1) having at least one zone (2, 3, 4). The optical fiber sensor system (10) comprises at least one optical fiber (11, 21, 31, 41) comprising a plurality of Fiber Bragg Gratings (20, 30, 40) for detecting a temperature change. Each of the Fiber Bragg Gratings (20, 30, 40) is reflecting radiation within a predetermined wavelength range. A radiation source unit (13) is arranged to emit radiation into the at least one optical fiber (11, 21, 31, 41). A radiation detector unit (14) is arranged to receive radiation from the at least one optical fiber (11, 21, 31, 41). A processing unit (15) is configured to identify a spectral response (22, 32, 42) of the received radiation and to determine a temperature change from the spectral response (22, 32, 42) of the received radiation in a predetermined wavelength range. Each of the at least one zone (2, 3, 4) solely has Fiber Bragg Gratings (20, 30, 40) which are reflecting radiation within the same predetermined wavelength range. The disclosure further relates to method for detecting a temperature change in a zone in an aircraft having at least one zone, by means of the optical fiber sensor system. Yet further the disclosure relates to an aircraft (1) comprising the optical fiber sensor system (10).

Claims

1. An optical fibre sensor system arranged to detect a temperature change in a zone in an aircraft having at least one zone, the optical fibre sensor system comprising:

at least one optical fibre comprising a plurality of Fibre Bragg Gratings for detecting a temperature change, wherein each of the Fibre Bragg Gratings is reflecting radiation within a predetermined wavelength range;

a radiation source unit arranged to emit radiation into the at least one optical fibre;

a radiation detector unit arranged to receive radiation from the at least one optical fibre;

the processing unit configured to identify a spectral response of the received radiation and to determine a temperature change from the spectral response of the received radiation in a predetermined wavelength range;

wherein each of the at least one zone solely has Fibre Bragg Gratings which are reflecting radiation within the same predetermined wavelength range; and

each of at least one Bragg wavelength of the spectral response is determined by identifying a rising or falling edge of the spectral response.

2. The optical fibre sensor system according to claim 1, wherein Fibre Bragg Gratings of each of the other zones are reflecting radiation within a different predetermined wavelength.

3. The optical fibre sensor system according to claim 1, wherein the processing unit is configured to monitor the temperature in each zone separately.

4. The optical fibre sensor system according to claim 1, wherein the aircraft comprises an alarm unit coupled to the optical fibre sensor system which indicates in which zone the temperature passes a temperature threshold.

5. The optical fibre sensor system according to claim 1, wherein each of the Fibre Bragg Gratings in each of the at least one zone has a unique spectral response within that corresponding predetermined wavelength range.

6. The optical fibre sensor system according to claim 1, wherein each of the at least one zone comprises at least four Fibre Bragg Gratings.

7. The optical fibre sensor system according to claim 1, wherein one of the at least one optical fibre extends along a plurality of the zones.

8. The optical fibre sensor system according to claim 1, wherein the processing unit is further configured to determine at least one Bragg wavelength of the spectral response and to match the at least one Bragg wavelength to the zone which solely has Fibre Bragg Gratings which are reflecting radiation within the corresponding predetermined wavelength range.

9. The optical fibre sensor system according to claim 8, wherein the processing unit is further configured to analyse analyze how the temperature in each of the zones changes by analyzing the speed at which each of the Bragg wavelengths of the spectral response moves.

10. An aircraft comprising an optical fibre sensor system according to claim 1.

11. Use of the optical fibre sensor system arranged to detect a temperature change in a zone in an aircraft according to claim 1, wherein the optical fibre sensor system detects a hot air leakage in the zone from a pipe comprising hot air.

12. Use of the optical fibre sensor system arranged to detect a temperature change in a zone in an aircraft according to claim 1, wherein the optical fibre sensor system detects a temperature change in a fuel tank in the zone.

13. A method for detecting a temperature change in a zone in an aircraft having at least one zone, by means of an optical fibre sensor system, the optical fibre sensor system comprising at least one optical fibre comprising a plurality of Fibre Bragg Gratings for detecting a temperature change, wherein each of the Fibre Bragg Gratings is reflecting radiation within a predetermined wavelength range, the method comprising the steps of;

emitting, from a radiation source unit, radiation into the at least one optical fibre;

receiving, by a radiation detector unit, radiation from the at least one optical fibre;

identifying, by a processing unit, a spectral response of the received radiation;

determining, by a processing unit, a temperature change from the spectral response of the received radiation in a predetermined wavelength range;

wherein each of the at least one zone solely has Fibre Bragg Gratings which are reflecting radiation within the same predetermined wavelength range; and

determining each of at least one Bragg wavelength of the spectral response by identifying a rising or falling edge of the spectral response.

14. The method according to claim 13, wherein Fibre Bragg Gratings of each of the other zones are reflecting radiation within a different predetermined wavelength.

15. The method according to claim 13, wherein the method further comprises the steps of:

determining at least one Bragg wavelength of the spectral response; and

matching the at least one Bragg wavelength to the zone which solely has Fibre Bragg Gratings which are reflecting radiation within the corresponding predetermined wavelength range.