Magnetic Flow Sensor for Sterile Medical Fluid Delivery
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Solution Overview
Problem
Existing fluid delivery systems for medical instruments face challenges in maintaining consistent fluid flow rates and detecting issues such as empty saline bags, clamped irrigation lines, or pump failures, while ensuring sterility and reducing endotoxin levels.
Innovation Solution
A flow measurement system that includes a magnetically sensitive flow channel with a ferrous body moving within a track, allowing for accurate measurement of fluid flow rates and detection of anomalies, integrated with a peristaltic pump assembly and a fluid manager to monitor and control fluid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow sensor is integrated into the fluid delivery system to monitor flow rates and detect anomalies, then measurement precision is improved, but the risk of endotoxin contamination and loss of sterility increases
Solution Approach 1:
The system divides the fluid delivery pathway into sterile and non-sterile zones. The flow sensor assembly is segmented from the main fluid path, with only a magnetic coupling interface penetrating the sterile barrier. This allows the sensor electronics to remain isolated from the fluid while still measuring flow through magnetic interaction with a ferrous body in the fluid path.
Solution Approach 2:
A magnetic field serves as an intermediary between the non-sterile sensor assembly and the sterile fluid path. The sensor detects flow by measuring changes in magnetic field caused by a ferrous body moving in the fluid, without direct contact between sensor components and fluid. This intermediary approach enables measurement while preserving sterility.
2Reliability
If electronic flow sensing components are placed in direct contact with the fluid path to enable real-time monitoring, then reliability of flow detection is improved, but sterility maintenance deteriorates
Solution Approach 1:
The system replaces direct mechanical contact between electronic sensors and fluid with a magnetic field-based detection mechanism. A ferrous body in the fluid path interacts with a magnetic field generated by the sensor, allowing flow detection through electromagnetic induction without mechanical contact. This substitution maintains reliability while preserving sterility.
3Object-affected harmful factors
If a peristaltic pump is used to maintain sterility by keeping fluid isolated from pump components, then sterility is improved, but the ability to accurately measure flow rate deteriorates
Solution Approach 1:
A magnetic field acts as an intermediary to transfer measurement information from the sterile fluid path to the non-sterile sensor assembly. The ferrous body moves with the fluid through the peristaltic pump, and its motion is detected by the magnetic sensor without breaking the sterile barrier. This enables accurate flow measurement while maintaining the sterility benefits of peristaltic pumping.
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 monitors and maintains desired fluid flow rates, detects potential issues like occlusions or pump failures, and maintains sterility by isolating electronic components from the fluid, ensuring reliable and safe fluid delivery to medical appliances.
Implementation Method 1
a magnetically sensitive flow channel with a ferrous body moving within a track
Implementation Method 2
pumping fluid from a fluid source, such as a bag, through medical tubing via a positive displacement pump, such as a peristaltic pump
Data Source
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AI summary
A flow measurement assembly includes a coupler and a flow channel (40). The coupler maintains a magnet (54) and a sensor (58) spaced from the magnet. The flow channel is positionable between the magnet and the sensor. The flow channel includes a housing having an inlet (42), an outlet (44) spaced from the inlet, and a flow conduit (56) fluidly open to the inlet and the outlet. A ferrous body (58) is movably disposed in the conduit. The sensor is configured to detect a frequency of a change within a magnetic field as the ferrous body travels within the flow conduit between the magnet and the sensor.