Non-Invasive Temperature Sensor with Reference Compensation
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Solution Overview
Problem
Invasive temperature measuring devices in industrial settings suffer from flow energy losses, abrasion, and reduced measurement accuracy due to thermal interactions with both the surface and ambient environment, leading to inaccurate medium temperature readings.
Innovation Solution
A non-invasive temperature measuring device with a measuring sensor and a reference sensor thermally connected to a common conductive element, arranged on the same thermal path between the medium and the processing unit, allowing for improved dynamic measurement accuracy by tapping into the thermal conduction path as a voltage divider.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a surface temperature sensor is used to measure medium temperature non-invasively, then flow energy losses and abrasion are avoided, but the sensor measures a mixed temperature between the medium and ambient temperature instead of the actual medium temperature
Solution Approach 1:
The patent introduces a reference temperature sensor as an intermediary element that measures the ambient temperature. This reference measurement is then used in a calculation algorithm to compensate for the thermal mixing effect and derive the actual medium temperature from the surface temperature sensor reading, thereby resolving the measurement inaccuracy without requiring invasive measurement.
Solution Approach 2:
The system uses feedback by continuously monitoring the ambient temperature through the reference sensor and using this information to adjust the calculation of medium temperature. The measured surface temperature and ambient temperature are fed into a calculation algorithm that compensates for thermal influences and provides the accurate medium temperature reading.
2Ease of manufacture
If the reference temperature sensor is mounted far away from the process in the transmitter head, then explosion protection is simplified, but the reference sensor reaches its thermal equilibrium value extremely slowly causing delays of several minutes
Solution Approach 1:
The patent applies dynamics by positioning the reference temperature sensor at an optimized distance from the process - close enough to quickly reach thermal equilibrium and respond rapidly to temperature changes, but far enough to maintain explosion protection. This dynamic positioning resolves the contradiction between response time and safety requirements.
3Measurement precision
If thermal insulation is provided for the mechanical connection between sensor and transmitter head, then measurement accuracy is improved, but the actual effect of the insulation is usually not known
Solution Approach 1:
The system uses self-service by employing the reference temperature sensor to automatically measure and characterize the thermal conditions at the sensor location. This eliminates the need for separate insulation characterization, as the reference sensor provides real-time data about the actual thermal state, allowing the system to self-adjust and compensate for insulation effects.
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 configuration enhances response to temperature changes, reduces measurement noise, and provides accurate medium temperature readings with minimal deviation from actual surface temperatures, even under rapid changes, while allowing for compact and robust designs suitable for high-temperature industrial applications.
Implementation Method 1
the at least one measuring sensor and the at least one reference sensor having a common measured value processing means, which has the ambient temperature, are connected. According to the invention, the at least one measuring sensor and the at least one reference sensor are thermally connected at different distances to the same thermally conductive element
Implementation Method 2
If the temperature sensor is designed as an electrical thermocouple, for example, the temperature of the sensor and thus the temperature of the medium can be determined by measuring the thermal voltage
Data Source
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AI summary
The invention relates to a temperature measuring device and a method for determining a medium temperature by means of the temperature of a surface enclosing the medium. According to the invention, at least one measuring sensor (11) and at least one reference sensor (12) are arranged along a main thermal connection path between the surface enclosing the medium and the surroundings, wherein at least one measuring sensor (11) is arranged near the measuring point and the thermal resistance (R1) between a measuring sensor (11) and a reference sensor (12) is smaller than the thermal resistance (R2) between the relevant reference sensor (12) and the surroundings.