Passive Heat-Flow Sensor With Multi-Directional Thermistors
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Solution Overview
Problem
Conventional passive heat-flow sensors are unable to accurately measure core body temperature due to their inability to detect heat flow in all directions and are sensitive to ambient temperature changes, leading to potential hypothermia detection issues in medical settings.
Innovation Solution
A passive heat-flow sensor with combined thermistor arrangements that measure both vertical and lateral heat flows, allowing for more precise temperature monitoring by including inner, upper, and lateral thermistors to account for heat flow in multiple directions and reduce sensitivity to environmental changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional passive heat-flow sensor measures only vertical heat flow, then the device complexity is low, but the measurement precision of core body temperature is insufficient
Solution Approach 1:
The sensor divides heat flow measurement into separate directional components using multiple thermistor arrangements. Vertical heat flow is measured by one arrangement while lateral heat flow is measured by another arrangement, allowing independent measurement of different heat flow directions to improve overall temperature measurement precision.
Solution Approach 2:
The invention extends measurement from one dimension (vertical heat flow only) to three dimensions by adding lateral heat flow measurement capability. This dimensional expansion captures heat flow in multiple directions (vertical and lateral), providing a more complete thermal picture for accurate core body temperature determination.
2Measurement precision
If a conventional passive heat-flow sensor is well insulated to measure core body temperature, then the measurement precision improves, but the sensor size increases
Solution Approach 1:
The sensor separates measurement functions into distinct thermistor arrangements oriented in different directions. By segmenting the measurement capability into vertical and lateral components, the sensor achieves comprehensive temperature measurement without requiring extensive insulation, thus maintaining a compact size while improving precision.
3Measurement precision
If a passive heat-flow sensor uses a large contact area, then the sensor can detect heat flow better, but the contact area is rarely thermally uniform leading to measurement errors
Solution Approach 1:
The large contact area is divided into multiple measurement zones with separate thermistor arrangements. Each arrangement measures heat flow in its specific location and direction, allowing the system to account for thermal non-uniformity across the contact surface by combining data from multiple segments rather than treating the area as uniform.
Solution Approach 2:
Different regions of the contact area are equipped with thermistor arrangements optimized for local measurement conditions. Each thermistor arrangement is positioned and oriented to capture heat flow characteristics specific to its location, accommodating variations in thermal properties across the contact surface.
4Ease of operation
If a passive heat-flow sensor is worn by a moving patient, then the ease of operation improves, but poor adhesion or air pockets cause inaccurate measurements
Solution Approach 1:
The sensor uses multiple distributed thermistor arrangements across the contact surface rather than a single centralized measurement point. This segmentation ensures that even if some areas experience poor adhesion or air pockets during patient movement, other arrangements maintain good contact and provide reliable measurements.
Solution Approach 2:
The multiple thermistor arrangements provide redundant measurement paths that can detect and compensate for contact quality variations. By comparing readings from different arrangements, the system can identify and compensate for areas with poor adhesion or air pockets, maintaining measurement accuracy during patient movement.
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 solution enables more accurate core body temperature measurement, reducing the risk of hypothermia detection errors and providing timely intervention in medical situations by incorporating lateral heat flow monitoring, which conventional sensors lack.
Implementation Method 1
measure heat flow between the inner thermistor and the upper thermistor
Implementation Method 2
each comprising an inner thermistor (arranged at an inner face of the sensor) and an upper thermistor (arranged at the upper surface of the sensor)
Data Source
AI summary
The invention describes a passive heat-flow sensor (1) comprising a contact face (11) for placement on a subject (8) during a temperature monitoring procedure; and a plurality of combined thermistor arrangements, wherein a combined thermistor arrangement comprises an inner thermistor (S1) arranged at an inner face of the sensor (1); an upper thermistor (S2) arranged at the upper surface of the sensor (1) and arranged relative to the inner thermistor (S1) to measure a vertical heat flow outward from the subject (8); and a lateral thermistor (S3) arranged relative to the inner thermistor (S1) to measure a horizontal heat flow along the contact face (11). The invention further describes a method of measuring the temperature of a subject (8) using a heat-flow sensor (1); and a temperature sensing arrangement (10) for monitoring the temperature of a subject (8) using a heat-flow sensor (1).