Portable Thermal Sensor Calibration Using Cryogenic Blackbody Target
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Solution Overview
Problem
Existing thermal sensor calibration methods are impractical due to the lack of portable and effective blackbody targets, especially in environments where access to sensors is limited, and current solutions fail to provide a suitable range of temperatures and a large, uniformly heated calibration target.
Innovation Solution
A portable thermal sensor calibration system that includes a shroud with a sensor aperture and a chamber containing a blackbody target, which is cooled or heated using a cryogenic fluid system, allowing for accurate calibration of thermal sensors in various environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If commercially available blackbody targets are used for calibration, then calibration can be performed, but the targets are not portable and have a limited lower scene temperature range of -40°C
Solution Approach 1:
The calibration system is divided into separate functional components: a portable shroud assembly containing the blackbody target, and a separate cryogenic fluid supply system. This segmentation allows the blackbody target to be made portable while maintaining access to extended temperature ranges through the connected fluid system.
Solution Approach 2:
The patent uses cryogenic fluid (liquid nitrogen or other refrigerants) delivered through fluid lines to cool the blackbody target below the traditional -40°C limit. This hydraulic/pneumatic approach enables extended temperature ranges while keeping the physical target compact and portable.
2Reliability
If thermal sensors are installed on buildings, towers, or vehicles, then the sensors are positioned for operational use, but access or removal of such sensors is not feasible
Solution Approach 1:
The calibration system is designed to be brought to the sensor location rather than requiring sensor removal. The portable shroud assembly with integrated blackbody target and cryogenic cooling can be positioned at the sensor site, allowing in-situ calibration without disturbing the installed sensor.
Solution Approach 2:
The portable shroud assembly acts as an intermediary calibration device that can be transported to and positioned at various sensor locations. This mediator enables calibration access without requiring direct sensor removal or complex disassembly of installed systems.
3Ease of operation
If a portable calibration system is created, then ease of operation is improved, but the system complexity increases due to cryogenic fluid requirements
Solution Approach 1:
The shroud assembly is designed as a universal calibration device that can be used with different sensor types and locations. The standardized interface and cryogenic cooling system provide multi-functional capability, reducing the need for multiple specialized calibration devices and thereby managing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system enables accurate and portable thermal sensor calibration across a wide temperature range, reducing the need for laboratory equipment and minimizing the effects of moisture and ice accretion, thus improving calibration accuracy and convenience.
Implementation Method 1
a fluid inlet fluidly coupled to the blackbody target, the fluid inlet to receive heat transfer fluid for calibration of the sensor
Implementation Method 2
providing cryogenic fluid to at least one of the blackbody target or the shroud
Implementation Method 3
a blackbody target disposed within the chamber
Data Source
AI summary
Methods and apparatus to calibrate thermal sensors are disclosed. A disclosed apparatus to calibrate a sensor includes a shroud defining a sensor aperture and a chamber, a blackbody target disposed within the chamber, and a fluid inlet fluidly coupled to the blackbody target, the fluid inlet to receive heat transfer fluid for calibration of the sensor.