Membrane Nebulizer Fluid Detection Using Drive Signal Phase Shift
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Solution Overview
Problem
Existing aerosol delivery devices struggle to efficiently and reliably detect the presence of fluid or liquid for aerosolization, which can lead to incomplete dosage delivery, inaccurate dosing, and inefficient power usage, particularly in inhalation nebulizers with membrane generators.
Innovation Solution
An aerosol delivery device with a vibratable membrane and a vibrator, equipped with a phase detector and evaluation unit, detects the presence of fluid by monitoring phase shifts in the drive signal due to temperature changes in the vibrator, allowing continuous operation without frequency variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing detection methods are used to detect fluid presence, then device complexity is reduced, but measurement precision and reliability of fluid presence detection deteriorate
Solution Approach 1:
The vibrator serves dual functions: it vibrates the membrane for aerosol generation and simultaneously acts as the detection element by monitoring its own impedance changes. This self-service approach eliminates the need for separate detection hardware, achieving high measurement precision while avoiding increased device complexity.
Solution Approach 2:
The patent replaces complex mechanical or optical detection systems with an electrical impedance-based detection method. By monitoring the electrical impedance of the vibrator, which changes in response to temperature variations caused by fluid presence, the system achieves accurate fluid detection without mechanical sensors or complex optical setups.
2Measurement precision
If frequency variations are used to detect fluid presence, then measurement precision improves, but productivity and continuous operation capability deteriorate
Solution Approach 1:
Instead of changing the vibration frequency to detect fluid presence, the patent monitors impedance changes at a constant operating frequency. The impedance varies with temperature, which changes when fluid is present or depleted. This allows continuous monitoring without frequency modulation, maintaining both high measurement precision and uninterrupted aerosol generation productivity.
Solution Approach 2:
The detection method enables continuous aerosol generation without interruptions for frequency sweeping or mode switching. The vibrator operates continuously at its optimal frequency for aerosol generation while simultaneously providing detection information through impedance monitoring, ensuring uninterrupted therapeutic action and maximum productivity.
3Loss of time
If fluid presence is not accurately detected, then device complexity remains low, but loss of time due to incomplete dosage delivery increases
Solution Approach 1:
The system implements real-time feedback monitoring of the vibrator's impedance, which changes as fluid is depleted. This feedback mechanism allows the device to detect fluid presence accurately and provide timely alerts or automatic shutdown, preventing incomplete dosage delivery and ensuring the full therapeutic dose is administered without unnecessary delays.
4Use of energy by moving object
If continuous operation without detection is used, then productivity is maintained, but loss of energy due to prolonged operation after fluid depletion increases
Solution Approach 1:
The impedance-based detection system provides real-time feedback on fluid presence, enabling the control system to shut down the vibrator automatically when fluid is depleted. This prevents continued operation and unnecessary energy consumption while maintaining full productivity during the actual aerosol generation period. The feedback mechanism ensures energy is only consumed when it produces useful therapeutic output.
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
This method enables efficient and accurate detection of fluid presence, ensuring complete aerosolization and reducing power consumption by avoiding interruptions, thus improving device efficiency and reliability.
Implementation Method 1
a phase detector which is configured to detect a phase shift of the drive signal
Implementation Method 2
an electronic temperature limiting circuit that compares a temperature-dependent electric signal occurring at the piezocrystal
Implementation Method 3
a vibrator configured to vibrate a fluid and to aerosolise the fluid by the membrane
Implementation Method 4
heat, such as Joule heat, generated by the vibrator
Data Source
AI summary
The invention relates to an aerosol delivery device (A, B) comprising an aerosol generator for generating an aerosol in the aerosol delivery device (A, B). The aerosol generator comprises a membrane (1) and a vibrator (7) which is configured to vibrate a fluid (3) and to aerosolise the fluid (3) by the membrane (1). The aerosol delivery device (A, B) further comprises a fluid reservoir (2) for receiving the fluid (3) to be aerosolised, wherein the fluid reservoir (2) is arranged in fluid communication with the membrane (1). Moreover, the aerosol delivery device (A, B) comprises a controller (10) which is configured to operate the vibrator (7), by supplying an electrical drive signal to the vibrator (7), so as to vibrate the fluid (3), a phase detector (13) which is configured to detect a phase shift of the drive signal, and an evaluation unit (13a) which is configured to detect the presence of fluid (3) in contact with the membrane (1) and/or in the fluid reservoir (2) on the basis of the phase shift detected by the phase detector (13). Further, the invention relates to a method of operating such an aerosol delivery device (A, B).