Explosion-proof thermal imaging system

Patent metadata

Field	Value
Publication number	US-10999536-B2
Application number	US-201514755094-A
Country	US
Kind code	B2
Filing date	Jun 30, 2015
Priority date	Jun 30, 2015
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

An explosion-proof thermal imaging system is provided. The system include an explosion-proof housing having a window that is configured to allow thermal radiation therethrough. An infrared camera is positioned within the explosion-proof housing and is disposed to receive and image thermal radiation that passes through the window. An emissivity target is disposed within a field of view of the infrared camera, but on an opposite side of the window from the infrared camera. A temperature sensor is operably coupled to the infrared camera and is configured to provide an indication of temperature proximate the emissivity target.

First claim

What is claimed is:

1. An explosion-proof thermal imaging system comprising:
an explosion-proof housing having a window that is configured to allow thermal radiation therethrough wherein the window is partially obscured by accumulated contaminate;
a guard disposed in front of the window;
an emissivity target disposed within the guard;
an infrared camera positioned within the explosion-proof housing and configured to capture an image of the emissivity target and generate an image-based temperature thereof;
a temperature sensor mounted to the guard and configured to sense a temperature proximate the emissivity target;
a controller, operably coupled to the temperature sensor, configured to determine a level of contamination on the window indicative of the accumulated contaminate based on a comparison of the image-based temperature of the emissivity target with the sensed temperature from the temperature sensor, and generate calibration information based on the comparison of the image-based temperature with the sensed temperature and provide subsequent calibrated thermal imaging based on the calibration information; and
wherein the controller is further configured to generate an output indicative of the level of contamination on the window based on the comparison of the image-based temperature with the sensed temperature.

2. The explosion-proof thermal imaging system of claim 1 , wherein the window is formed of a material that is susceptible to damage from impacts.

3. The explosion-proof thermal imaging system of claim 1 , wherein the temperature sensor is mounted to a collar that mounts the guard to the explosion-proof housing.

4. The explosion-proof thermal imaging system of claim 1 , wherein the guard is a net guard formed of crisscrossing wires.

5. The explosion-proof thermal imaging system of claim 1 , wherein the temperature sensor is operably coupled to measurement circuitry of the infrared camera.

6. The explosion-proof thermal imaging system of claim 5 , wherein the temperature sensor is wirelessly coupled to the infrared camera.

7. The explosion-proof thermal imaging system of claim 1 , wherein the infrared camera is configured to wireless communicate image data to a remote device.

8. The explosion-proof thermal imaging system of claim 7 , wherein the wireless communication is in accordance with a wireless process industry standard protocol.

9. The explosion-proof thermal imaging system of claim 1 , wherein the infrared camera includes a microbolometer.

10. The explosion-proof thermal imaging system of claim 1 , wherein the controller is configured to engage a heater of the housing based on the indication of temperature proximate the emissivity target.

11. The explosion-proof thermal imaging system of claim 1 , wherein the housing complies with an explosion-proof rating.

12. The explosion-proof thermal imaging system of claim 1 , wherein the emissivity target and the temperature sensor constitute an integral unit.

13. The explosion-proof thermal imaging system of claim 1 , wherein the temperature sensor is mounted to the emissivity target.

14. A method of operating a thermal imaging system in a hazardous environment, the method comprising:
placing an infrared camera in an explosion-proof housing having an impact guard disposed in front of a window and orienting the infrared camera to view through the window of the housing;
causing the infrared camera to image an emissivity target, disposed within the impact guard in front of the window and protected from contamination, and determine an optically-derived value of the emissivity target based on the image;
sensing a temperature proximate the emissivity target using a temperature sensor;
determining a level of contamination on the window indicative of accumulated contaminate based on a comparison of the optically-derived value of the emissivity target with the sensed temperature from the temperature sensor;
generating calibration information based on the comparison of the optically-derived value with the sensed temperature;
generating an output indicative of the level of contamination on the window based on the comparison of the optically-derived value with the sensed temperature; and
providing subsequent calibrated thermal images based on the calibration information.

15. An explosion-proof thermal imaging system comprising:
an explosion-proof housing having a window disposed adjacent an impact guard, the window being configured to allow thermal radiation therethrough wherein the window is partially damaged from a physical impact;
an infrared camera positioned within the explosion-proof housing and disposed to receive and image thermal radiation that passes through the window;
an emissivity target disposed on the impact guard on an opposite side of the window from the infrared camera, but within a field of view of the infrared camera;
wherein the infrared camera is configured to image the emissivity target and determine an image-based temperature of the emissivity target based on the image, and wherein the system is configured to provide a diagnostic indication, relative to a level of damage of the window, based on a comparison of the image-based temperature to a sensed temperature from a temperature sensor located on the impact guard; and
wherein the system is further configured to generate an output indicative of the level of damage of the window based on the comparison of the image-based temperature with the sensed temperature.

16. The explosion-proof thermal imaging system of claim 15 , wherein the system is configured to provide an indication relative to the window based on uniformity across the net guard.

Assignees

• Rosemount Inc

Inventors

• Rud Jason H
• Kitzman Andrew J
• Kienitz Sascha Ulrich

Classifications

• H04N23/555

  for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes · CPC title

• H04N23/51 Primary

  Housings · CPC title

• H04N23/50

  Constructional details · CPC title

• G01J5/70

  Passive compensation of pyrometer measurements, e.g. using ambient temperature sensing or sensing of temperature within housing · CPC title

• H04N23/23

  from thermal infrared radiation · CPC title