Handheld Probe Vibration Isolation for Acoustic Pulse Reflectometry
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Solution Overview
Problem
The sensitivity of Acoustic Pulse Reflectometry (APR) systems for tube inspection is limited by low Signal to Noise Ratio (SNR), particularly due to nonlinear distortions in loudspeakers at high signal levels and mechanical vibrations, which hinder the detection of small or distant defects.
Innovation Solution
A novel handheld probe configuration that vibration-isolates the acoustic elements and improves the acoustic wave transfer function using materials like rubber and foam to minimize mechanical linkages and nonlinear distortions, enhancing the SNR by optimizing the engagement of electro/acoustic transducers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the intensity of the input signal is increased to improve SNR, then the signal strength increases, but nonlinear distortions in the loudspeaker increase
Solution Approach 1:
The patent introduces a pre-distortion processing stage that acts as an intermediary between the input signal and the loudspeaker. The processor applies inverse nonlinear characteristics to the input signal before it reaches the loudspeaker, compensating for the loudspeaker's nonlinear distortions. This allows the system to operate at higher signal levels for improved SNR while the pre-distortion processing cancels out the resulting nonlinear distortions.
2Power
If the loudspeaker is driven at high levels to improve SNR, then the signal intensity increases, but the distortion increases
Solution Approach 1:
The patent applies preliminary action by processing the input signal in advance through a distortion processing stage that pre-compensates for the expected nonlinear distortions. The processor calculates and applies inverse distortion characteristics before the signal reaches the loudspeaker, ensuring that even when the loudspeaker is driven at high power levels, the output signal maintains high quality with reduced distortions.
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 solution significantly improves the Signal to Noise Ratio, allowing for the detection of faint reflections and enabling the use of higher power transmitters with reduced nonlinear distortions, thereby enhancing the detection of defects in tubes.
Implementation Method 1
loudspeakers used to convert the electronic signal into an acoustic signal
Implementation Method 2
microphone and mounting hardware to be connected to a measured tube
Implementation Method 3
The new configuration improves the transfer function of the acoustic wave from the loudspeaker to the tube and back to the microphone
Data Source
AI summary
Exemplary embodiments of a handheld probe (HHP) of an Acoustic pulse reflectometry (APR) system are disclosed. Embodiments of the HHP can comprise a loudspeaker and microphone that are vibration isolated from each other and from the tube under test. In some embodiments the microphone can be isolated from the housing of the HHP. In other embodiments the housing of the HHP can be isolated from the loudspeaker. In another embodiment the housing of the probe can be isolated from the tube under test. Yet, some embodiments combine all of this isolation options. In such embodiment the loudspeaker is isolated from the housing, the housing is isolated from the tube under test, and the microphone is isolated from the housing, and so on. Isolation can be achieved by using materials that absorb vibration, material such as but not limited to rubber, foam, silicone, etc.