Pitot-Static Sensing With a Movable Barrier Against Ice Blockage
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Solution Overview
Problem
Aircraft pitot-static instruments are susceptible to malfunction due to blockage of inlet ports and conduits by foreign object debris (FOD) or ice formation, leading to inaccurate airspeed readings.
Innovation Solution
A pitot system with a hermetically sealed chamber and a movable barrier that determines stagnation pressure through deflection, reducing the likelihood of blockage and malfunction by using impact pressure to deflect the barrier, which is monitored by sensors to calculate airspeed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pitot tube with conduit is used to measure stagnation pressure, then the instrument can detect airspeed, but the inlet port and conduit are susceptible to blockage by FOD or ice formation causing malfunction
Solution Approach 1:
The patent extracts the vulnerable conduit component from the stagnation pressure measurement system and replaces it with a diaphragm that directly presents the inlet port to the airflow. This eliminates the enclosed conduit space where FOD and ice could accumulate and cause blockages, while still allowing pressure detection through the flexible diaphragm element.
Solution Approach 2:
The patent introduces a diaphragm as an intermediary element between the inlet port and the pressure sensing mechanism. The diaphragm transmits the stagnation pressure from the airflow while its flexible nature and direct exposure design prevent FOD and ice from creating complete blockages, maintaining measurement capability under contaminated conditions.
2Measurement precision
If the inlet port is positioned directly into the fluid flow to detect stagnation pressure, then airspeed measurement is enabled, but the inlet port is exposed to FOD entry causing blockage
Solution Approach 1:
The patent removes the protective conduit that previously enclosed the pressure sensing path and replaces it with an exposed diaphragm design. This extraction eliminates the hidden spaces where FOD could lodge and block pressure transmission, while the diaphragm's flexibility allows it to maintain measurement precision even with partial FOD contact.
3Reliability
If a hermetically sealed chamber with movable barrier is used, then blockage resistance is improved, but the device complexity increases
Solution Approach 1:
The patent employs a flexible diaphragm as the movable barrier in the hermetically sealed chamber. This thin film element provides effective blockage resistance by sealing the chamber while its flexibility allows it to respond to pressure changes and accommodate minor FOD contact without complete failure, achieving high reliability with relatively simple construction.
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 system maintains accurate airspeed measurements even with FOD or ice entry, as the movable barrier deflects proportionally to stagnation pressure, reducing the risk of instrument failure and enhancing pilot situational awareness with redundant systems.
Implementation Method 1
impact pressure exerted against the movable barrier by fluid in the body
Implementation Method 2
hermetically sealed chamber positioned in the body
Data Source
Figure 1
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AI summary
A pitot system includes a body including an inlet port and a hermetically sealed chamber positioned in the body. The hermetically sealed chamber includes a movable barrier in fluid communication with the inlet port. The pitot system also includes one or more first sensors configured to provide first signals, to a computer, based on deflection of the movable barrier due to impact pressure exerted against the movable barrier by fluid in the body. The first signals correspond to a stagnation pressure of fluid that entered the body via the inlet port.