Differential Force Sensor for Low Flow Rate Measurement
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Solution Overview
Problem
Existing fluid delivery systems for medicinal fluids face challenges in accurately measuring and controlling flow rates, especially at low rates, due to system compliance and the need for costly sterilization or disposal, which can lead to inefficiencies and increased risk in manual administration.
Innovation Solution
A differential force sensor system utilizing two piezoresistive sense die packaged in close proximity, mounted near the patient's entry point, coupled with an onboard communications device and flow controller, to monitor and control fluid flow rates through a fluid line, minimizing system compliance and ensuring precise delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fluid delivery systems use long disposable tubing to deliver medicinal fluids, then the system is easy to manufacture and dispose, but the system compliance is too high to accurately measure dynamic flow at very low flow rates
Solution Approach 1:
The patent extracts the flow measurement function from the distant pump location and places it directly at the patient entry point by mounting the differential force sensor on the catheter near the patient. This eliminates the compliance of long tubing from the measurement system, allowing accurate flow measurement at very low flow rates while maintaining the benefits of disposable tubing.
Solution Approach 2:
The patent introduces a differential force sensor as an intermediary device that measures flow by detecting pressure differential across a known restriction. This sensor acts as a mediator between the fluid flow and the measurement system, providing accurate flow data without being affected by the compliance of long disposable tubing.
2Device complexity
If manual injection procedures are used to administer medicinal fluids, then the system complexity is reduced, but the risk of manual administration errors increases
Solution Approach 1:
The patent implements a feedback system where the differential force sensor continuously monitors flow rate and provides real-time data to a controller. The controller adjusts pump operations based on this feedback to maintain precise flow rates, eliminating manual administration errors while keeping the overall system relatively simple.
Solution Approach 2:
The system incorporates automatic flow rate control that self-regulates based on sensor measurements, eliminating the need for manual flow adjustments by healthcare providers. The system serves itself by automatically maintaining precise flow rates through the differential force sensor and controller combination.
3Ease of manufacture
If disposable tubing is used in fluid delivery systems, then sterilization costs are reduced, but the time required for fluid delivery at low flow rates increases due to system compliance
Solution Approach 1:
The patent extracts the flow measurement point from the pump end of the tubing and places it directly at the patient entry point on the catheter. This removes the compliant disposable tubing from the measurement path, allowing accurate real-time flow monitoring and control without the time delays caused by tubing compliance, while maintaining the cost benefits of disposable tubing.
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 precise control of fluid flow at very low rates, reducing the time for fluid delivery and minimizing patient discomfort, while being cost-effective and reducing the risk of manual administration errors.
Implementation Method 1
The differential force sensor includes the use of two piezoresistive sense die packaged in close proximity to one another
Data Source
AI summary
A fluid delivery system and method for measuring flow at a patient utilizing a differential force sensor in order to precisely control the flow of fluid at very low flow rates. The system includes a fluid line through which a fluid is conveyed to the patient, and a flow controller that selectively varies a rate of flow of the fluid through the fluid line. The differential force sensor can be mounted very close to a point of entry of the fluid into the patient's body. An onboard communications device is controllably coupled to the flow controller and to the force sensor, responds to an output signal, and provides a feedback to the flow controller in a closed-loop process. The system can pump the fluid at a higher frequency until the flow rate is actually reached at the patient and then adjust to the flow rate needed to ensure patient health.