Weld-Sealed Air Data Probe Insert for Corrosion-Protected Heating
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Solution Overview
Problem
Pitot probes in aircraft are prone to heater failure due to corrosion from environmental contamination, as the heater is exposed to moisture and contaminants, leading to reduced functionality and frequent replacements.
Innovation Solution
A probe head design that includes an insert with a heater positioned within a groove, surrounded by an outer shell, and sealed via a tip weld, which prevents direct exposure to moisture and contaminants, enhancing heat transfer and reducing corrosion by hermetically encapsulating the heater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater is exposed to the environment for heating the probe, then the heating function is effective, but the heater is susceptible to corrosion from moisture and contaminants
Solution Approach 1:
The probe head is divided into separate components: an insert containing the heater and an outer shell. This segmentation allows the heater to be isolated from the external environment while maintaining its heating function, resolving the contradiction between effectiveness and corrosion resistance.
Solution Approach 2:
The outer shell acts as an intermediary barrier between the heater and the external environment. It protects the heater from moisture and contaminants while allowing thermal energy to pass through, enabling the heater to function reliably without direct exposure to harmful factors.
2Reliability
If the heater is sealed from the environment, then corrosion is reduced, but heat transfer to the external environment may be impaired
Solution Approach 1:
The outer shell is designed as a thin-walled structure that provides hermetic sealing against environmental contaminants while maintaining adequate thermal conductivity. This allows the shell to protect the heater from corrosion while still enabling effective heat transfer to the external environment.
3Reliability
If a hermetic seal is created around the heater, then corrosion is prevented, but manufacturing complexity increases
Solution Approach 1:
The probe head is segmented into an insert and an outer shell, with the heater contained within the insert. This segmentation creates a simple hermetic seal interface between the insert and outer shell, protecting the heater from contaminants while avoiding complex sealing mechanisms.
Solution Approach 2:
The heater is pre-positioned within the insert and the seal is formed during assembly before the probe is put into service. This preliminary action ensures hermetic sealing is achieved during manufacturing, preventing corrosion without requiring complex operational sealing systems.
4Reliability
If the heater is enclosed in an insert and outer shell, then corrosion is reduced, but device complexity increases
Solution Approach 1:
The probe head is divided into an insert containing the heater and an outer shell. This segmentation provides effective protection while keeping each component relatively simple in design, balancing protection needs with manufacturing simplicity.
Solution Approach 2:
The insert and outer shell are combined through welding to form a unified protective structure around the heater. This merging creates a robust enclosure that protects the heater from corrosion while maintaining a relatively simple overall device structure.
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 design effectively seals the heater from external contaminants, reducing corrosion and improving heat transfer, thereby enhancing the reliability and longevity of air data probes in adverse environmental conditions.
Implementation Method 1
The tip weld is connected to the first end of the insert and the first end of the outer shell
Implementation Method 2
A braze connects the second end of the insert and a second end of the outer shell
Implementation Method 3
heaters are positioned within pitot probes to ensure the pitot probes function properly in rain and icing environments
Data Source
Figure 1A
Figure 1B
Figure 2
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 first end, a second end opposite the first end, and a body portion extending between the first end and the second end. The body portion includes a groove. The portion of the heater is positioned within the groove. The outer shell surrounds the insert and the portion of the heater. The outer shell (24) includes a tip portion defining a first end of the outer shell and a body portion extending from the tip portion defining a second end of the outer shell. The tip weld (30) is between the outer shell and the first end of the insert, and the braze (26) is between the insert and the second end of the outer shell adjacent a second end of the insert. The portion of the heater is hermetically sealed between the insert and the outer shell.