Pitot Tube Capacitance Sensing for Blockage Detection
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Solution Overview
Problem
Pitot tube sensing apparatuses are prone to blockages by foreign objects, leading to erroneous pressure measurements, which is critical in applications like aircraft speed determination where accuracy is essential.
Innovation Solution
A pitot tube sensing apparatus equipped with a capacitor having electrodes on opposing sides of the channel to measure capacitance, allowing detection of foreign objects within the channel based on capacitance changes, with optional electrical shielding and a system to compare parameters against thresholds for reliable determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pitot tube is used to measure pressure for determining fluid flow speed, then the measurement capability is provided, but the channel can be blocked by foreign objects leading to erroneous measurements
Solution Approach 1:
A capacitor is introduced as an intermediary sensing element between the pitot tube channel and the measurement system. The capacitor detects foreign objects through capacitance changes caused by the dielectric properties of potential blockages, providing an early warning mechanism that prevents erroneous pressure measurements before they occur.
Solution Approach 2:
The patent replaces purely mechanical pressure measurement with a hybrid system that incorporates electrical sensing (capacitance measurement). This substitution allows for non-contact detection of foreign objects, eliminating the need for mechanical intervention and enabling earlier detection of blockage conditions.
2Reliability
If capacitance sensing is added to detect foreign objects, then blockage detection capability is improved, but device complexity increases
Solution Approach 1:
The capacitor serves multiple functions: it acts as part of the normal circuitry while simultaneously functioning as a sensing element for foreign object detection. This multi-functionality reduces the need for separate dedicated sensing components, thereby limiting the increase in device complexity while maintaining reliable blockage detection capability.
Solution Approach 2:
The existing electrical components and circuitry in the pitot tube system are utilized to provide the sensing function. The capacitor leverages the existing electrical environment and power supply, eliminating the need for separate power sources or complex processing systems, thus keeping the added complexity minimal.
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
Enhances the reliability of detecting and preventing blockages, ensuring accurate pressure measurements and aircraft speed calculations by generating alerts when foreign objects are present.
Implementation Method 1
a capacitor comprising two electrodes on opposing sides of the channel; and a system configured to: measure a parameter indicative of a capacitance between the two electrodes
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
A pitot tube sensing apparatus and method are disclosed which can determine the presence or absence of a foreign object within the pitot tube sensing apparatus. The pitot tube sensing apparatus includes a pitot tube comprising a channel, a pressure sensor coupled to the channel, a capacitor and a system. The capacitor comprises two electrodes on opposing sides of the channel. The system measures a parameter indicative of a capacitance between the two electrodes and determines the presence or absence of a foreign object within the channel based on the parameter.