Infrared inspection system for heaters comprised of positive temperature coefficient resistors

Patent metadata

Field	Value
Publication number	US-12146794-B2
Application number	US-202117302959-A
Country	US
Kind code	B2
Filing date	May 17, 2021
Priority date	May 17, 2021
Publication date	Nov 19, 2024
Grant date	Nov 19, 2024

Abstract

An apparatus and method for inspecting articles incorporating positive temperature coefficient resistors. The inspection apparatus includes a computing device, a power source, a housing, a support, and a thermal imager, each mounted within an interior volume of the housing. The inspection method includes receiving a first thermal image of the unpowered article mounted within the support and receiving a second thermal image of the powered article after an optimized time delay. The method further includes outputting a health indication of the positive temperature coefficient resistors based on a comparison of the first thermal image and the second thermal image.

First claim

The invention claimed is:

1. A method of inspecting an article comprising a plurality of positive temperature coefficient resistors, the method comprising:
receiving, by a thermal imager, a first thermal image of the article at a first time;
identifying two or more exterior features of the article based on the first thermal image;
receiving, by the thermal imager, a second thermal image of the article at a second time after the first time;
supplying, using a power source, a target voltage across each of the plurality of positive temperature coefficient resistors after the first time and up to the second time;
identifying a region within the first and second thermal images corresponding to a position of a first positive temperature coefficient resistor among the plurality of positive temperature coefficient resistors based on the two or more exterior features of the article; and
outputting a health indication of the first positive temperature coefficient resistor based on a comparison between the first thermal image and the second thermal image, wherein the health indication represents one of an operative condition, an inoperative condition, and a degraded condition of the first positive temperature coefficient resistor.

2. The method of claim 1 , wherein the comparison between the first and second images includes determining a temperature difference within the region between the first and second thermal images and comparing the temperature difference to a differential temperature criterion.

3. The method of claim 2 , wherein the comparison between the first and second thermal images includes:
determining a first average temperature of the region based on the first thermal image;
determining a second average temperature of the region based on the second thermal image; and
determining the temperature difference within the region based on the first average temperature and the second average temperature.

4. The method of claim 1 , wherein the region has a geometrically similar shape to the first positive temperature coefficient resistor, and wherein an area of the region is smaller than an area of the first positive temperature coefficient resistor.

5. The method of claim 1 , wherein the two or more exterior features of the article are identified based on a model of the article.

6. The method of claim 1 , further comprising:
associating the health indication with a part number and a serial number of the article; and
transmitting, via a communications network, the health indication, the part number, and the serial number to a database.

7. The method of claim 1 , further comprising:
installing the article within a housing bound by walls, each wall having an emissivity greater than 0.8.

8. The method of claim 1 , further comprising:
outputting a plurality of health indications based on the comparison of the first thermal image and the second thermal image, wherein each health indication of the plurality of health indications corresponds to one of the plurality of positive temperature coefficient resistors, and wherein the health indication of the first temperature coefficient resistor is among the plurality of health indications, and wherein each health indication represents one of an operative condition, an inoperative condition, and a degraded condition of respective positive temperature coefficient resistors.

9. An apparatus for inspecting an article that includes a plurality of positive temperature coefficient resistors, the apparatus comprising:
a housing enclosing an interior volume;
a thermal imager mounted within the interior volume;
a support within the interior volume that includes an interface adapted to receive the article;
a power source; and
a computing device comprising a processor and computer-readable memory encoded with instructions that, when executed by the processor, cause the apparatus to:
receive, by the thermal imager, a first thermal image of the article at a first time;
identify two or more exterior features of the article based on the first thermal image;
receive, by the thermal imager, a second thermal image of the article at a second time after the first time;
supply, using the power source, a target voltage across each of the plurality of positive temperature coefficient resistors after the first time and up to the second time;
identify a region within the first and second thermal images corresponding to a position of a first positive temperature coefficient resistor among the plurality of positive temperature coefficient resistors based on the two or more exterior features of the article; and
output a health indication of the first positive temperature coefficient resistor based on a comparison between the first thermal image and the second thermal image, wherein the health indication represents one of an operative condition, an inoperative condition, and a degraded condition of the first positive temperature coefficient resistor.

10. The apparatus of claim 9 , wherein the computing device includes a user interface and communicates to a database via a communications network, and wherein the computing device is encoded with instructions that, when executed by the processor, cause the apparatus to retrieve two or more exterior features of the article from a model of the article based on a part number received by the computing device via the user interface.

11. The apparatus of claim 9 , wherein the computing device is encoded with instructions that, when executed by the processor, cause the apparatus to:
associate the health indication with the part number and a serial number of the article; and
transmitting, via a communications network, the health indication, the part number, and the serial number to a database.

12. The apparatus of claim 9 , wherein the computing device is encoded with instructions that, when executed by the processor, cause the apparatus to determine a temperature difference within the region between the first and second thermal images and compare the temperature difference to a differential temperature criterion.

13. The apparatus of claim 12 , wherein the computing device is encoded with instructions that, when executed by the processor, cause the apparatus to:
determine a first average temperature within the region based on the first thermal image;
determine a second average temperature within the region based on the second thermal image; and
determine the temperature difference within the region based on the first average temperature and the second average temperature.

14. The apparatus of claim 9 , wherein the region has a geometrically similar shape to the first positive temperature coefficient resistor, and wherein an area of the region is smaller than an area of the first positive temperature coefficient resistor.

15. The apparatus of claim 9 , wherein the computing device includes a display, and wherein the computing device is encoded with instructions that, when executed by the processor, cause the apparatus to output the health indication to the display.

16. The apparatus of claim 9 , wherein the computing device is encoded with instructions that, when executed by the processor, cause the apparatus to output a plurality of health indications based on the comparison of the first thermal image and the second thermal image, wherein each health indication of the plurality of health indications corresponds to one of the plurality of positive temperature coefficient resistors, and wherein the health indication of the first temperature coefficient resistor is among the plurality of health indications, and wherein e

Assignees

• Rosemount Aerospace Inc

Inventors

• Hanson Daniel
• Schwartz Richard Alan

Classifications

• H04N23/23

  from thermal infrared radiation · CPC title

• G06T2207/30164

  Workpiece; Machine component · CPC title

• G06T2207/10048

  Infrared image · CPC title

• G06T7/001

  using an image reference approach · CPC title

• G01J2005/0077

  Imaging · CPC title