Encapsulated Air Data Probe Heater for Corrosion Resistance

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Solution Overview

Problem

Pitot probes in aircraft are susceptible to heater failure due to environmental corrosion, as the heaters are exposed to contamination, leading to reduced functionality and frequent replacements.

Innovation Solution

A probe head design that encapsulates the heater within a sealed structure by brazing an insert with a wound heater to an outer shell, ensuring complete sealing and protection from external contaminants, while maintaining effective heat transfer and ice prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the heater is exposed to the external environment in traditional pitot probes, then the heater can be easily accessed and installed, but the heater is susceptible to corrosion from environmental contamination

Engineering Contradiction:

Improveheater installationVSAvoidheater corrosion resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The heater is nested within a sealed cavity formed by the insert and outer shell, creating a protected environment that isolates the heater from external contaminants while maintaining thermal functionality for ice prevention

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The insert acts as an intermediary structure that provides a sealed mounting environment for the heater, separating the heater from direct exposure to external contaminants while allowing thermal energy transfer to the probe exterior

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the heater is sealed within the probe head, then the heater is protected from corrosion, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveheater corrosion resistanceVSAvoidprobe head structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The probe head is segmented into distinct components (insert, outer shell, heater) that can be manufactured separately and then assembled through brazing, allowing for simplified individual part fabrication while achieving a complex sealed structure through modular construction

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heater is nested within the sealed cavity formed by the insert and outer shell, creating a protected environment that isolates the heater from external contaminants while maintaining thermal functionality for ice prevention

Inventive Principle:

Principle #7Nested doll (Nesting)

3Duration of action of stationary object

If the heater is fully encapsulated, then the lifespan of the heater is extended, but the thermal transfer efficiency may be reduced

Engineering Contradiction:

Improveheater lifespanVSAvoidthermal transfer efficiency

Core Design Contradiction:

Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

The insert and outer shell are designed with specific thermal properties and geometric features that optimize heat transfer pathways from the encapsulated heater to the probe exterior, ensuring efficient thermal energy transmission while maintaining the sealed protective environment

Inventive Principle:

Principle #3Local quality

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 enhances the durability and thermal control of pitot probes, reducing corrosion risks and extending the lifespan of the heater by keeping it sealed from environmental contamination, thus improving operational reliability and reducing maintenance needs.

Implementation Method 1

heaters are positioned within pitot probes to ensure the pitot probes function properly in rain and icing environments

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

maintaining effective heat transfer and ice prevention

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

brazing an insert with a wound heater to an outer shell

Methodology Applied

Scientific EffectBrazing: Brazing

Data Source

PatentEP3715859B1Air data probe with fully-encapsulated heater

Publication Date: 2023.05.03 ROSEMOUNT AEROSPACE INC

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Figure 2A

AI summary

A probe head (12) of an air data probe includes an insert (20), a portion of a heater, an outer shell, a tip weld, and a braze. The insert includes a tip portion making up a tip of the air data probe, an end portion (38), and a body portion extending between the tip portion and the end portion. The body portion includes a groove (46). The portion of the heater is positioned within the groove. The outer shell surrounds the body portion of the insert and the portion of the heater. The tip weld is located between the tip portion of the insert and a first end of the outer shell, and the braze is located between the end portion of the insert and a second end of the outer shell. The portion of the heater is hermetically sealed between the insert and the outer shell.