Pitot-Static Airspeed Sensing With a Sealed Barrier Chamber
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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 indications.
Innovation Solution
A pitot system with a hermetically sealed chamber and a movable barrier that detects stagnation pressure through deflection, reducing the risk of blockage and malfunction by using impact pressure to deflect the barrier, which is monitored by sensors to determine airspeed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pitot tube with conduit is used to detect stagnation pressure, then the structure is simple and easy to manufacture, but the inlet port and conduit are susceptible to blockage by foreign object debris (FOD) or ice formation, leading to malfunction
Solution Approach 1:
The patent removes the conduit component from the pitot tube design. Instead of having a conduit that extends from the chamber to the sensor device, the sensor device is positioned directly in the chamber to detect stagnation pressure. This extraction of the conduit eliminates the blockage vulnerability while maintaining the essential pressure detection function.
Solution Approach 2:
The patent introduces a movable barrier as an intermediary element between the inlet port and the sensor device. This barrier is positioned in the chamber and deflects in response to stagnation pressure, providing mechanical coupling between the pressure field and the sensor while preventing direct exposure of the sensor to FOD and ice particles.
2Measurement precision
If the inlet port is positioned directly into the fluid flow to detect stagnation pressure, then the pressure detection is accurate, but the inlet port is exposed to foreign object debris (FOD) and ice particles that can cause blockage
Solution Approach 1:
The movable barrier serves as a protective intermediary that allows accurate stagnation pressure detection while shielding the sensor device from harmful FOD and ice particles. The barrier deflects in response to pressure changes, transmitting the pressure signal to the sensor without exposing it to contaminants.
Solution Approach 2:
The movable barrier is implemented as a flexible diaphragm or thin-walled structure that can deflect elastically in response to stagnation pressure changes. This flexible structure maintains pressure coupling accuracy while providing a sealed barrier against particle ingress.
3Reliability
If a hermetically sealed chamber with movable barrier is used to detect stagnation pressure, then the likelihood of malfunction is reduced by orders of magnitude, but the device complexity increases
Solution Approach 1:
The patent combines the chamber, movable barrier, and sensor device into an integrated assembly where the sensor is positioned directly in the hermetically sealed chamber. This merging eliminates the need for separate conduits and external connections, reducing potential failure points while maintaining the protective sealing.
Solution Approach 2:
The hermetically sealed chamber with movable barrier creates a self-contained pressure detection system that does not require external conduits or connections. The system serves itself by using the barrier's deflection to directly indicate pressure changes, eliminating vulnerabilities associated with external piping and connections.
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 significantly reduces the likelihood of malfunction by orders of magnitude, maintaining accurate airspeed measurements even when FOD enters the inlet port, and provides redundancy with conventional pitot tubes for enhanced pilot situational awareness.
Implementation Method 1
deflection of the movable barrier due to impact pressure exerted against the movable barrier by fluid in the body
Data Source
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.