Inline Sensor Assembly for Aircraft Probe Heater Monitoring
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Solution Overview
Problem
Aircraft air data probes' resistive heating elements deteriorate due to prolonged usage and frequent switching, leading to incorrect measurements and the need for premature replacement, necessitating effective monitoring to prevent breakdowns.
Innovation Solution
A current sensor assembly with high electromagnetically permeable enclosures and tubes is used to monitor the heater system's input and return wires, sensing current changes and differential currents to detect degradation and alert for maintenance or replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heating element is used for prolonged periods and frequently switched, then the heating element deteriorates and breaks down, but continuous monitoring to detect degradation increases device complexity
Solution Approach 1:
The patent implements a monitoring system that continuously measures the electrical characteristics (resistance, current, voltage) of the heating element and provides feedback to detect degradation. This feedback mechanism enables early warning of heating element failure, allowing maintenance before complete breakdown occurs, thus resolving the contradiction between reliability and monitoring complexity.
Solution Approach 2:
The monitoring system utilizes the existing electrical circuitry and inherent electrical properties of the heating element itself to perform self-diagnosis. By measuring changes in resistance and current characteristics, the system enables the heating element to monitor its own health status without requiring external complex diagnostic equipment.
2Loss of time
If the heating element is monitored continuously to detect degradation, then premature replacement can be prevented, but the monitoring system increases device complexity
Solution Approach 1:
The sensor assembly is designed to perform multiple functions: it monitors heating element current, measures temperature, and detects degradation patterns simultaneously. This multi-functionality reduces the need for separate dedicated sensors for each parameter, thereby reducing overall device complexity while enabling comprehensive monitoring to optimize replacement timing.
Solution Approach 2:
The patent introduces high electromagnetically permeable enclosures and tubes as intermediary components that shield the sensing circuits from induced currents and electromagnetic interference. These intermediary shielding structures enable accurate current measurement without requiring complex filtering or correction circuits, simplifying the overall monitoring system design.
3Measurement precision
If high electromagnetically permeable enclosures and tubes are added to shield circuits from induced current, then measurement accuracy improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The shielding structure is divided into separate modular components: high electromagnetically permeable enclosures for each current sensor module and additional permeable tubes for specific wire pathways. This segmentation allows each shielding component to be manufactured and tested independently, then assembled into the complete sensor assembly, improving manufacturability while maintaining measurement precision.
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 solution allows for timely detection of heating element degradation, preventing failures and reducing the need for premature replacements by monitoring current changes and providing alerts, thus ensuring accurate air data measurements.
Implementation Method 1
The first current sensor module is shielded from magnetic flux in the return wire with a first high electromagnetically permeable enclosure around the first current sensor core
Implementation Method 2
A high electromagnetically permeable tube extends through the first current sensor core and is configured to extend around one of the heater input wire and the heater return wire
Implementation Method 3
Magnetic flux in the input wire is sensed by the first current sensor module to determine input current in the input wire
Implementation Method 4
a resistive heating element is installed in the air data probe which prevents ice formation on the air data probe. An operational voltage is provided through the heating element to provide heating for the air data probe
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A sensor assembly for monitoring a heater system for an aircraft probe sensor includes a current sensor module (36) with a current sensor core (38) and a high electromagnetically permeable enclosure (40) around the current sensor core. An input wire pathway (28) extends through the current sensor core and is configured to receive a heater input wire (22). A return wire pathway (30) extends through the current sensor core and is configured to receive a heater return wire (24). A high electromagnetically permeable tube (52, 54) extends through the current sensor core and is configured to extend around one of the input wire and the heater return wire.