Weeping Airspeed Sensor With Passive Moisture Separation
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Solution Overview
Problem
Small unmanned aerial vehicles (sUAVs) face issues with airspeed sensors freezing and clogging due to moisture accumulation, which can reduce flight autonomy and safety.
Innovation Solution
The airspeed sensor design incorporates circulation chambers to separate moisture from incoming airflow, expelling it through drainage ports, and integrates static pressure measurement, eliminating the need for heating elements, thus reducing sensor footprint and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating elements are used to prevent moisture accumulation in airspeed sensors, then reliability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts and removes the heating element from the airspeed sensor design, replacing it with a passive moisture separation system using circulation chambers and drainage ports. This eliminates the need for active heating while maintaining reliability in wet conditions.
Solution Approach 2:
The circulation chamber system operates passively using natural airflow circulation to separate and drain moisture from the sensor. The system serves itself by utilizing the existing air flow dynamics rather than requiring external power for active moisture removal.
2Reliability
If heating elements are used to prevent moisture accumulation in airspeed sensors, then reliability is improved, but weight increases
Solution Approach 1:
The heating element is completely removed from the sensor design, eliminating its weight contribution. The replacement passive moisture separation system uses lightweight circulation chambers and drainage structures that significantly reduce overall sensor weight.
3Measurement precision
If separate Pitot tube and static pressure sensor are used, then measurement accuracy is improved, but device complexity and footprint increase
Solution Approach 1:
The patent combines the total pressure measurement (Pitot tube) and static pressure measurement into a single integrated sensor housing. The circulation chamber system serves both measurement paths, and the drainage infrastructure is shared, reducing overall system complexity while maintaining separate measurement capabilities.
Solution Approach 2:
The circulation chamber and drainage port system serves multiple functions: it separates moisture for both the total pressure and static pressure measurement paths, provides structural support, and enables passive moisture management for the entire integrated sensor assembly.
4Reliability
If circulation chambers are added to separate moisture, then reliability is improved, but device complexity increases
Solution Approach 1:
Instead of using active mechanisms to prevent moisture entry, the patent inverts the approach by allowing moisture entry and then passively separating and draining it through circulation chambers. This reverse engineering approach simplifies the overall system by eliminating complex active prevention mechanisms.
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 separates moisture from airflow, ensuring reliable airspeed measurements in both wet and dry conditions, enhancing flight safety and autonomy without the need for heating elements.
Implementation Method 1
one or more circulation chambers, including a first circulation chamber (i.e., first TP chamber), operatively coupled to the ingress through an elongated tube, wherein the first circulation chamber defines a first volume for retaining the first airflow and separating moisture from the first airflow
Implementation Method 2
the first circulation chamber comprising a first surface, defined in the first volume, with which the first airflow contacts to circulate in the first volume
Implementation Method 3
According to Bernoulli's principle, total pressure is the sum of static pressure and dynamic pressure. Dynamic pressure, as a measure of airspeed, can then be determined as the difference between the two measurements.
Implementation Method 4
at least one drainage port, including a first drainage port, extending from the first volume, wherein the first drainage port is configured to expel liquid of the separated moisture from the first airflow
Data Source
AI summary
An airspeed instrument that employs one or more circulation chambers to receive and circulate incoming airflow to separate moisture from the air that can be then expelled via a drainage port. The exemplary airspeed instrument apparatus can be implemented as a small instrument appropriately sized for small UASs and aircraft. The separation chamber has an angled bottom surface that leads to a sampling port positioned at the top of the chamber, which prevents moisture from entering the sampling port into the measuring electronics. In some embodiments, the exemplary airspeed instrument apparatus is configured with an integrated static port sensor.