Fluid Warmer Outlet Temperature Correction for Accurate Heating Control
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Solution Overview
Problem
Existing fluid warming devices for extracorporeal blood treatment apparatuses face challenges in accurately measuring fluid temperature at the outlet, particularly due to the limitations of contact temperature sensors like thermistors and thermocouples.
Innovation Solution
The implementation of a correction model for temperature measurement errors, derived from empirical data sets, to improve the accuracy of fluid temperature measurement at the outlet of the fluid warming device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact temperature sensors (thermistors or thermocouples) are used at the outlet of the fluid warming device, then the device structure remains simple and cost-effective, but the temperature measurement accuracy deteriorates
Solution Approach 1:
The patent replaces the direct contact mechanical measurement system with an optical measurement system. Specifically, it uses the reflection characteristics of the fluid outlet region to determine temperature, substituting physical contact sensors with optical field interactions. This is achieved by measuring reflected light properties that correlate with temperature without requiring sensor contact with the fluid or outlet surface.
Solution Approach 2:
The patent utilizes changes in optical reflection characteristics (analogous to color changes) of the fluid outlet region as a function of temperature. By detecting variations in reflected light properties that correspond to temperature-dependent surface or fluid optical property changes, the system determines temperature non-contactly. This approach converts temperature information into optical signal variations for measurement.
2Reliability
If contact temperature sensors are used at the outlet, then the device remains structurally simple, but the reliability of temperature measurement deteriorates
Solution Approach 1:
The patent replaces the direct contact mechanical measurement system with an optical measurement system. Specifically, it uses the reflection characteristics of the fluid outlet region to determine temperature, substituting physical contact sensors with optical field interactions. This is achieved by measuring reflected light properties that correlate with temperature without requiring sensor contact with the fluid or outlet surface.
3Measurement precision
If complex insulation design is implemented to improve temperature measurement accuracy, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces the direct contact mechanical measurement system with an optical measurement system. Specifically, it uses the reflection characteristics of the fluid outlet region to determine temperature, substituting physical contact sensors with optical field interactions. This is achieved by measuring reflected light properties that correlate with temperature without requiring sensor contact with the fluid or outlet surface.
Solution Approach 2:
The patent introduces light as an intermediary medium between the temperature measurement function and the fluid outlet. Instead of direct sensor contact, optical signals interact with the fluid or outlet surface, and the reflected light carries temperature information. This intermediary approach enables non-contact measurement without requiring complex thermal insulation or contact sensor protection structures.
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
This approach enhances the reliability and accuracy of fluid temperature measurement, ensuring effective temperature control for extracorporeal blood treatment, while maintaining a structurally simple, cost-effective, and non-complex insulation design.
Implementation Method 1
contact temperature sensors, like thermistors or thermocouples
Implementation Method 2
heating elements operatively active in the heating zone to heat the fluid warming path
Data Source
AI summary
A fluid warming device for an extracorporeal blood treatment apparatus, comprises: an outlet temperature sensor (31) operatively active at an outlet (22) of a fluid warming path (23) to detect a measured outlet temperature (To) of a fluid leaving the fluid warming device (18); an electronic control unit (29) operatively connected to the outlet temperature sensor (31). The electronic control unit (29) is configured to perform the following procedure: receiving, from the outlet temperature sensor (31) a signal correlated to a measured outlet temperature (To); correcting the measured outlet temperature (To) through a correction model to obtain an actual fluid outlet temperature (Tout); adjusting a heating power (Ph) of heating elements to keep the actual fluid outlet temperature (Tout) at a set reference temperature value (Tset). The correction model is an empirical model of a measurement error (E) derived from a plurality of experimental data sets, the measurement error (E) being a difference between the measured outlet temperature (To) and the actual fluid outlet temperature (Tout).