Acoustic Volume Sensing for Wearable Fluid Dispensing Accuracy
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Solution Overview
Problem
Existing portable devices for controlled release of therapeutics face challenges such as malfunction rates, size, weight, and cost, and require a wearable solution for automatic delivery of drugs over time, especially for medications with poor absorption or requiring frequent administration.
Innovation Solution
A wearable fluid delivery system with a pumping chamber and force application assembly that restricts retrograde flow, using a shape-memory actuator to pressurize the chamber and control fluid flow, integrated with a tortuous conduit and passive valve for unidirectional flow, and a sensor for flow measurement to adjust operation based on measured parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If portable devices are designed for controlled release of therapeutics, then automatic delivery capability is improved, but device size and weight increase
Solution Approach 1:
The device is divided into separate components: a reusable pump unit and disposable cartridges containing the therapeutic fluid. This segmentation allows the heavy electronic control components to be minimized in the reusable unit while the disposable cartridges can be lightweight, reducing overall device weight for automatic delivery.
Solution Approach 2:
The patent employs disposable cartridges that contain the therapeutic fluid and are replaced periodically. This allows the complex automatic delivery mechanism to be simplified and miniaturized in the reusable pump unit, reducing its weight, while the disposable cartridges handle the fluid storage function.
2Volume of moving object
If device size is reduced for portability, then wearability is improved, but manufacturing complexity increases
Solution Approach 1:
By segmenting the device into a reusable pump unit and disposable cartridges, each component can be manufactured independently using optimized processes. The pump unit can be precisely manufactured with integrated microfluidics, while cartridges use simpler molding techniques, reducing overall manufacturing complexity despite small size.
Solution Approach 2:
The patent implements a nested structure where the disposable cartridge is inserted into the reusable pump unit. This nesting allows compact integration of multiple functions in a small volume while maintaining separate manufacturing processes for each component, simplifying production.
3Reliability
If force application assembly is used to restrict retrograde flow and pressurize chamber, then fluid delivery reliability is improved, but device complexity increases
Solution Approach 1:
The force application assembly combines the retrograde flow restriction function and the pressurization function into a single integrated mechanism. This merging reduces the number of separate components needed, thereby reducing device complexity while maintaining reliable fluid delivery through both functions.
Solution Approach 2:
The force application assembly serves multiple functions: it restricts retrograde flow, pressurizes the pumping chamber, and controls fluid ejection. This multi-functionality reduces the overall device complexity by eliminating the need for separate mechanisms for each function while ensuring reliable fluid delivery.
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 enables reliable, efficient, and adjustable delivery of therapeutic fluids, reducing the need for frequent administration and improving patient compliance by providing a compact, wearable solution for controlled release of medications.
Implementation Method 1
using a shape-memory actuator. Also optionally, using the shape-memory actuator includes inducing a phase change in a shape memory wire to transmit a force around a pulley to the force application assembly
Data Source
AI summary
An apparatus for determining the volume of fluid dispensed. The apparatus has an acoustic volume sensor that acoustically excites a reference volume and a measurement chamber with a loudspeaker and measures the acoustic response with microphones acoustically coupled to the reference and the measurement chamber. The loudspeaker and sensing microphones are connected to the measurement chamber by separate ports. A detachable dispensing chamber is coupled to the acoustic volume sensor. The volume of the fluid dispensed is determined by a processor based on the acoustic response of the microphones to acoustic excitement by the loudspeaker.