Variable-Volume Dispensing Chamber for Precise Wearable Drug Flow
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Solution Overview
Problem
Existing fluid delivery systems for therapeutic compounds face challenges such as poor absorption, hepatic metabolism, and the need for frequent administration, which can be addressed by developing a wearable device for controlled release of drugs, but these devices are often bulky, costly, and prone to malfunctions.
Innovation Solution
A method and device for dispensing fluid using a resilient variable-volume dispensing chamber with a finite fluid impedance, where fluid is pumped into the chamber and the volume is measured acoustically to control the flow, ensuring precise delivery through a control loop and a patch-sized housing with a pump and sensor system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If portable devices are designed for controlled release of therapeutics, then the need for frequent administration is reduced, but the device size, weight, and cost increase
Solution Approach 1:
The device is divided into two main segments: a reusable controller and disposable cartridges. The cartridge contains the reservoir and pumping mechanism, while the controller handles control electronics. This segmentation allows the heavy components to be replaced periodically rather than carrying the entire device weight continuously.
Solution Approach 2:
The patent employs a compliant chamber that changes volume dynamically during operation. The chamber expands during fluid intake and contracts during delivery, utilizing elastic deformation to store and release mechanical energy, thereby reducing the need for heavy power sources and motors.
2Duration of action of moving object
If portable devices are designed for controlled release of therapeutics, then the need for frequent administration is reduced, but the device complexity increases leading to higher malfunction rates
Solution Approach 1:
The compliant chamber serves multiple functions automatically: it acts as a fluid reservoir, a pump mechanism through its expansion and contraction, and a volume sensor through pressure transduction. This self-service capability reduces the need for separate mechanical pumps, valves, and sensors, thereby simplifying the overall device architecture.
Solution Approach 2:
The patent introduces a compliant chamber as an intermediary element between the fluid source and the delivery mechanism. This chamber mediates the transfer of fluid while providing inherent feedback through pressure changes, simplifying the control system and reducing the need for complex electronic sensors and actuators.
3Measurement precision
If accurate fluid volume measurement is implemented, then precise fluid delivery is achieved, but the device size and cost increase
Solution Approach 1:
The compliant chamber acts as an intermediary that converts fluid volume changes into pressure changes, which are then measured by a compact pressure sensor. This indirect measurement approach enables precise volume monitoring without requiring bulky displacement sensors or complex measurement systems.
Solution Approach 2:
The patent replaces traditional mechanical volume measurement mechanisms (such as piston displacement or graduated cylinders) with a pressure-based sensing system. The compliant chamber's elastic deformation under pressure provides a direct mechanical-to-pressure transduction that can be measured by small, low-cost pressure sensors.
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 enables a portable, efficient, and accurate delivery of therapeutic fluids, reducing the need for frequent administration and addressing the malfunctions of existing devices by providing a compact, cost-effective, and reliable system for controlled release.
Implementation Method 1
The pump is capable of pressurizing the dispensing chamber to force fluid through a high-impedance flow path
Implementation Method 2
repeatedly measuring a parameter related to volume of the dispensing chamber over time... acoustically exciting gas in an acoustically contiguous region to produce an acoustic response therein
Data Source
AI summary
A method of dispensing fluid includes three processes. A first one of these processes includes pumping fluid into a resilient variable-volume dispensing chamber. The dispensing chamber is in series with a normally present finite fluid impedance and an output. The impedance is sufficient so as to cause expansion of the dispensing chamber as it receives pumped fluid even while some fluid flows through the output. Another one of these processes includes repeatedly measuring a parameter related to volume of the dispensing chamber over time. A third one of these processes includes controlling the pumping of fluid based on repeated measurements of the parameter to produce a desired fluid flow through the output. A corresponding system for dispensing fluid implements these processes.