Non-Invasive Flow Rate Measurement Using Heat Pulse Transit Time
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Solution Overview
Problem
Existing non-invasive liquid flow rate measurement devices are complex, expensive, and struggle to provide accurate measurements, especially for low flow rates, which is crucial in applications like medical devices and analytical chemistry.
Innovation Solution
A system with a heat producing element and temperature sensors that create a heat pulse marker in the liquid, allowing for non-invasive measurement of flow rates by calculating the transit time of the marker between the heating and sensing elements, with a second sensor providing a baseline temperature for self-regulation and ambient temperature compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If non-invasive measurement is used to preserve liquid sterility, then liquid contamination is prevented, but measurement accuracy deteriorates
Solution Approach 1:
The patent uses an intermediary substance (acoustic wave or heat marker) that is introduced into the liquid to enable measurement without direct contact. The acoustic wave propagates through the liquid and its velocity is measured to determine flow rate, while the heat marker is introduced upstream and its temperature detected downstream. Both methods use intermediaries that do not contaminate the liquid but enable accurate non-invasive measurement.
Solution Approach 2:
The patent replaces mechanical contact-based measurement systems with acoustic or thermal field-based systems. Instead of using mechanical probes that physically contact the liquid, the invention uses acoustic waves or heat markers that interact with the liquid through field interactions, eliminating mechanical contact and associated contamination risks while maintaining measurement capability.
2Object-affected harmful factors
If existing non-invasive devices are used, then liquid sterility is maintained, but measurement accuracy for low flow rates deteriorates
Solution Approach 1:
The patent employs periodic action by introducing acoustic waves or heat markers at specific intervals upstream of the measurement section. The periodic introduction of these markers enables continuous monitoring of flow rate, including low flow rates, by measuring the time between marker introductions and their detection downstream. This periodic measurement approach improves accuracy for low flow rates while maintaining non-invasive operation.
3Measurement precision
If complex measurement systems are used, then measurement capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and isolates the essential measurement function from complex systems. By focusing solely on introducing an acoustic wave or heat marker and measuring its transit time or velocity, the invention eliminates unnecessary components and complexity found in existing systems. This extraction approach maintains measurement capability while significantly reducing device complexity and cost.
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 offers accurate, non-invasive, and cost-effective liquid flow rate measurement, suitable for low volume flows, maintaining accuracy across varying temperatures and liquid types, and is adaptable to different tube sizes and materials.
Implementation Method 1
a heat producing element and a temperature sensor that is downstream of the heat producing element in the direction of the liquid flow. The heat producing element applies a heat pulse marker to the liquid flowing in a tube placed in the housing
Implementation Method 2
The temperature sensor senses the heat marker in the flowing liquid
Data Source
AI summary
A system and method for measuring the flow rate of a liquid in a tube non-invasively has a heating element that generates energy that is applied to the liquid to produce a heat marker that is detected by a temperature sensor located at a known distance from the heating element and the flow rate is calculated from measuring the travel time of the heat marker from the heating element to the sensor. A second temperature sensor measures the ambient temperature of the liquid before the heat marker is produced and detection of the heat marker is made on the basis of the difference between the ambient temperatures and the temperature of the heat marker.