Flow Rate Sensor With Eddy Current Coils For Drug Delivery Occlusion Detection
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Solution Overview
Problem
Current drug delivery devices lack effective contactless methods for detecting occlusions and contaminations in liquid flow, such as air bubbles, which can affect the accuracy of drug delivery and type identification.
Innovation Solution
A flow rate sensor system utilizing coils arranged around sections of varying diameters of a tube, where the impedance changes due to eddy currents caused by liquid flow are measured, allowing for contactless detection of occlusions and contamination types by analyzing the complex impedance of the coils, enhanced by magnetic guides with air gaps to improve magnetic flux coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contactless flow detection is implemented using coils and eddy currents, then occlusion and contamination detection capability is improved, but device complexity increases due to additional sensor components
Solution Approach 1:
The patent replaces mechanical or invasive flow detection methods with an electromagnetic sensing system. Coils generate magnetic fields that induce eddy currents in the liquid, and impedance changes in these coils provide contactless detection of occlusions and contaminations, eliminating the need for physical contact sensors within the fluid path.
Solution Approach 2:
The patent introduces magnetic guides with air gaps as intermediary elements between the coils and the liquid. These magnetic guides enhance the coupling of magnetic flux to the liquid, improving the eddy current effect and thereby enhancing the sensitivity of the impedance-based detection without requiring direct contact between the sensor and the liquid.
2Measurement precision
If multiple coils with different diameters are used to detect contamination types, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the sensing system into multiple discrete coils, each positioned around sections of the tube with different diameters. Each coil independently measures impedance changes, and by comparing the measurements from multiple coils with known different diameters, the system can identify contamination types based on their differential effects on eddy currents.
Solution Approach 2:
The patent utilizes changes in physical parameters - specifically the diameter of the tube sections where coils are positioned - to enhance contamination detection. By having coils at different diameters, the system creates varied magnetic flux coupling conditions that produce distinctive impedance change patterns for different contamination types, enabling precise identification.
3Power
If magnetic guides with air gaps are introduced to improve magnetic flux coupling, then eddy current strength is improved, but manufacturing complexity increases
Solution Approach 1:
The magnetic guides with air gaps serve as intermediary structures that mediate between the coils and the liquid. The air gaps create optimal magnetic flux coupling by concentrating the magnetic field lines through the liquid while preventing direct contact between the magnetic guide and the fluid, thereby enhancing eddy current strength without compromising sterility or requiring complex sealing arrangements.
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
Enables accurate, contactless detection of flow rate and contamination types, ensuring reliable drug delivery by determining impedance changes related to flow rate and material properties, thereby preventing occlusions and ensuring proper drug delivery.
Implementation Method 1
at least one coil arranged in the vicinity of the tube in such a manner that an eddy current in the liquid due to the liquid's flowing affects an impedance of the coil
Implementation Method 2
an eddy current in the liquid due to the liquid's flowing affects an impedance of the coil
Data Source
Figure 1~2
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Figure 5~6
AI summary
The invention relates to a flow rate sensor (1) for determining a flow rate of a liquid within a tube (2), the flow rate sensor (1) comprising at least one coil (1.1, 1.2) arranged in the vicinity of the tube (2) in such a manner that an eddy current in the liquid due to the liquid's flowing affects an impedance of the coil (1.1, 1.2).