Air Data Probe Heater Using Low Melting Point Metal

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Solution Overview

Problem

Traditional air data probes with heating elements face challenges in achieving uniform heat distribution due to complex manufacturing processes, leading to cold spots and reduced lifespan, and are costly and time-intensive to produce.

Innovation Solution

Incorporating a low melting point metal within a cavity between the probe body and housing, which transitions to a liquid state when the heater element is engaged, providing improved thermal conductivity and eliminating the need for precise shaping and brazing of the heater cable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a heating wire is disposed within or close to the probe wall with molten metal applied to surround the wire, then heat transfer characteristics between the heater wire and the probe wall are improved, but the manufacturing process becomes complex and time-intensive

Engineering Contradiction:
Improveheat transfer characteristicsVSAvoidmanufacturing efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent changes the physical state parameter of the metal from solid to liquid during manufacturing, allowing it to flow and conform to the heater wire and probe wall geometry, then solidifies it to create optimal thermal contact. This parameter change enables improved heat transfer without complex brazing or shaping operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The molten metal acts as an intermediary material between the heater wire and the probe wall, filling the cavity and creating intimate thermal contact. This intermediary substance facilitates efficient heat transfer from the wire to the wall without requiring direct mechanical or metallurgical bonding.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If complex manufacturing processes with precise shaping and brazing of heater cable are used, then heat distribution uniformity is improved, but production costs increase and manufacturing time increases

Engineering Contradiction:
Improveheat distribution uniformityVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The molten metal self-adjusts and self-distributes within the cavity, naturally conforming to the heater wire and probe wall surfaces. This self-service behavior eliminates the need for precise manual shaping and positioning, achieving uniform heat distribution through the metal's inherent fluidity and thermal conductivity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical processes (shaping, brazing, precise positioning) with a thermal-fluid process. The molten metal's flow and solidification replace mechanical assembly operations, achieving comparable or superior manufacturing precision with simpler, less costly processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If heater cable is precisely shaped and brazed to housing, then thermal stress on heater element is reduced, but device complexity increases

Engineering Contradiction:
Improveheater element lifespanVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent separates the thermal contact function from the structural bonding function. The molten metal provides thermal contact without requiring metallurgical bonding (brazing), dividing the manufacturing steps into simpler, independent operations that reduce overall device complexity while maintaining reliability.

Inventive Principle:
Principle #1Segmentation

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

This solution enhances heat distribution, reduces thermal stress on the heater element, and simplifies the manufacturing process, resulting in better de-icing and icing prevention with fewer cold spots and reduced production costs.

Implementation Method 1

engaging the heater element causes at least a portion of the low melting point metal to transition from a solid state to a liquid state

Methodology Applied
Scientific EffectPhase change (solid to liquid): Phase Change

Implementation Method 2

low melting point metal disposed within the cavity between the probe body and the housing, wherein engaging the heater element causes at least a portion of the low melting point metal to transition from a solid state to a liquid state

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

heater element disposed within the cavity between the probe body and the housing

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3159700B1Air data probe heater utilizing low melting point metal
Publication Date: 2018.02.14 HONEYWELL INTERNATIONAL INC
  • EP3159700B1 patent drawingFigure 1
  • EP3159700B1 patent drawingFigure 2
  • EP3159700B1 patent drawingFigure 3

AI summary

An air data probe includes a probe body. The air data probe also includes a housing surrounding the probe body, wherein a cavity is defined between the probe body and the housing. The air data probe also includes a heater element disposed within the cavity between the probe body and the housing. The air data probe also includes a low melting point metal disposed within the cavity between the probe body and the housing, wherein engaging the heater element causes at least a portion of the low melting point metal to transition from a solid state to a liquid state.