Symmetric Thermal Flow Sensing for Small Sterile Conduits
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Solution Overview
Problem
Existing fluid flow measurement technologies struggle to accurately measure small fluid flows in conduits, particularly in medical applications like intravenous tubing, often requiring contact with the fluid and are non-sterile or single-use.
Innovation Solution
A fluid flow measuring apparatus with a housing containing a thermal source and symmetrically positioned upstream and downstream sensors, which measure temperature changes to calculate flow rate without contacting the fluid, using a controller to analyze thermal signatures and symmetrical relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing fluid flow measurement technologies are used, then fluid flow can be measured, but measurement precision is poor for small flows and the device requires contact with fluid making it non-sterile or single-use
Solution Approach 1:
The patent introduces an intermediary thermal sensor system that measures fluid flow indirectly through thermal conductivity changes in the conduit wall, rather than direct contact with the fluid. The thermal sensor detects temperature differences caused by fluid flow across the conduit wall, maintaining sterility while enabling precise measurement of small flows.
Solution Approach 2:
The patent replaces traditional mechanical flow measurement methods with a thermal-based detection system. Instead of using mechanical elements that contact the fluid, the system uses thermal sensors to detect flow-induced temperature changes through the conduit wall, achieving both non-contact measurement and sterility.
2Measurement precision
If thermal sensors are positioned close to the thermal source, then measurement sensitivity increases, but thermal interference from the source affects sensor accuracy
Solution Approach 1:
The patent positions thermal sensors asymmetrically relative to the thermal source, placing them at specific distances and angles that optimize the detection of flow-induced thermal patterns while minimizing direct exposure to the source's thermal radiation. This asymmetric arrangement allows sensors to detect flow-related temperature differences without being overwhelmed by source thermal interference.
Solution Approach 2:
The patent creates different thermal environments for different sensors, with each sensor positioned to detect specific thermal patterns. The thermal source is configured to create localized thermal zones that allow sensors to measure flow characteristics at different positions along the conduit, with each sensor experiencing optimized thermal conditions for its specific measurement function.
3Measurement precision
If the apparatus is designed for high precision measurement of small flows, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent designs a universal thermal sensor apparatus that can measure various fluid flow rates and types through a single integrated system. The thermal source and sensor array are configured to detect flow-induced thermal patterns across different flow conditions, eliminating the need for multiple specialized devices while maintaining high measurement accuracy.
Solution Approach 2:
The patent combines multiple thermal sensors and the thermal source into a single integrated housing that interfaces with the conduit. This merged design consolidates what could be separate complex components into one unified apparatus, reducing overall system complexity while achieving precise flow measurement through the coordinated operation of integrated elements.
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
Accurately measures small fluid flows in conduits with high precision, ensuring sterility and reusability, suitable for low flow rates, and adaptable to different tubing types.
Implementation Method 1
A thermal source can be located in the housing and adjacent the throughway... causing the thermal source to pulse one of heating and cooling energy to the outer surface of the conduit
Implementation Method 2
measuring temperature at the upstream sensor to determine a change in temperature over time at the upstream sensor; and measuring temperature at the downstream sensor to determine a change in temperature over time at the downstream sensor
Data Source
AI summary
A fluid flow measuring apparatus and method can be configured to measure fluid flow in a conduit when the conduit is located in the fluid flow measuring apparatus. The apparatus can include a housing including a throughway configured to accept the conduit through which fluid flows, and a thermal source (either cooling or heating source) located in the housing and adjacent the throughway. A plurality of sensors can be positioned adjacent the throughway and spaced from the thermal source in upstream and downstream directions such that the thermal source is located between the sensors which are symmetrically located about the thermal source. A controller can be connected to sensors and configured to calculate flow rate of the fluid passing through the conduit, wherein flow rate calculation is dependent on the symmetrical relationship between the sensors about the thermal source.