Impedance-Based Liquid Detection for Infusion Device Leakage
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Solution Overview
Problem
External infusion devices for diabetes management face challenges in reliably detecting leaks, which can lead to unpredictable device behavior or failure, especially during activities that expose the device to water or humidity.
Innovation Solution
A liquid detection system within the infusion device case uses a set of electrodes and an impedance measurement circuit to determine if liquid is present, with a microprocessor triggering an alarm when impedance values fall below a threshold, and includes features to differentiate between liquid and humidity, and dynamically adjust thresholds based on environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional leak detection methods are used, then device simplicity is maintained, but detection reliability deteriorates due to inability to distinguish liquid from humidity
Solution Approach 1:
The patent replaces mechanical or simple physical leak detection methods with an electrical impedance-based detection system. Electrodes measure impedance changes to detect liquid presence, substituting complex mechanical sensing with electrical measurement that can reliably distinguish liquid from humidity through impedance characteristics
Solution Approach 2:
The system monitors impedance parameter changes over time and compares them against threshold values. By tracking parameter variations and using threshold-based detection, the system achieves reliable leak detection while maintaining manageable complexity through quantitative measurement rather than complex qualitative analysis
2Measurement precision
If impedance measurement is used to detect liquid, then detection accuracy is improved, but false alarms from humidity increase
Solution Approach 1:
The system dynamically adjusts impedance thresholds based on environmental conditions and historical data. By making the detection criteria adaptive rather than static, the system maintains high detection accuracy while reducing false alarms from humidity, as thresholds evolve to account for normal environmental variations
Solution Approach 2:
The system incorporates feedback mechanisms that monitor impedance measurements over time and adjust detection parameters accordingly. This feedback loop allows the system to learn from false alarm patterns and refine its detection algorithm, improving precision while minimizing harmful false positives
3Reliability
If continuous monitoring is implemented, then leak detection reliability is improved, but energy consumption increases
Solution Approach 1:
The system implements periodic impedance measurements rather than truly continuous monitoring. By sampling at optimized intervals and using event-triggered measurements (e.g., when impedance changes exceed a threshold), the system maintains reliable leak detection while significantly reducing average power consumption compared to constant monitoring
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 effectively detects liquid ingress, reducing the risk of device failure and allowing users to confidently use their infusion devices in various conditions without compromising reliability, enabling timely troubleshooting and minimizing malfunctions.
Implementation Method 1
an impedance measurement circuit coupled to the first electrode set to determine impedance values between the first positive electrode and the first negative electrode
Data Source
AI summary
A medical therapy system including liquid detection is disclosed. A medical therapy includes a case with an interior and an exterior. Within the interior of the case is the liquid detection system that includes a first electrode set with a first positive electrode and a first negative electrode. The liquid detection system further includes an impedance measurement circuit coupled to the first electrode set to determine impedance values between the first positive electrode and the first negative electrode. A threshold detector compares impedance values between the first electrode set to a first threshold impedance. A microprocessor is programmed to initiate an alarm when measured impedance from the first electrode set is below the first threshold impedance.