Dual-Sensor Temperature Measurement Device for Installation Error Correction
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Solution Overview
Problem
Existing temperature measurement devices with contact thermometers in closed measuring tubes suffer from installation errors due to heat flow between the medium and the environment, which are not effectively corrected by prior devices, especially in applications requiring high functional reliability and precision.
Innovation Solution
A device using a resistance-based main sensor and a thermoelectric-based auxiliary sensor, both arranged with a fixed offset within the measuring tube, allows for the correction of installation errors while ensuring high functional reliability by differentially influencing measurement values due to changes in insulation resistance, and compensating for dynamic errors through differing reaction times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a closed measuring tube with a temperature sensor is used to measure medium temperature, then the device structure is simple and robust, but installation errors occur due to heat flow between the medium and environment
Solution Approach 1:
The measuring tube is divided into multiple sections with temperature sensors positioned at different locations (at least two sensors: one at the end facing the medium and another at the process connection end). This segmentation allows detection of temperature gradients and heat flow patterns, enabling correction of installation errors while maintaining the simple closed-tube structure.
Solution Approach 2:
The device uses feedback from multiple temperature sensors to detect heat flow directions and magnitudes. Based on this feedback, the system calculates and corrects installation errors, compensating for thermal influences from the environment without requiring a complex open-tube design.
2Measurement precision
If multiple temperature sensors are arranged offset along the longitudinal axis to correct installation errors, then measurement precision improves, but device complexity increases
Solution Approach 1:
The multiple temperature sensors serve dual functions: they detect both the medium temperature and the heat flow pattern within the measuring tube. This multi-functionality allows a single sensor arrangement to perform both measurement and error correction, reducing overall device complexity despite using multiple sensors.
Solution Approach 2:
The system changes the parameter of sensor positioning from a single location to multiple standardized positions along the longitudinal axis. These positions are optimized to detect characteristic heat flow patterns, enabling error correction through parameter optimization rather than complex sensor configurations.
3Strength
If thick-wall metallic protective tubes are used for the measuring tube, then mechanical strength and protection improve, but thermal transfer from medium to sensor decreases, increasing installation error
Solution Approach 1:
Instead of trying to improve thermal transfer through the thick wall, the solution moves to another dimension by placing sensors at multiple locations along the tube's longitudinal axis. This allows detection of temperature gradients and heat flow patterns that develop along the tube length, enabling mathematical correction of the thermal lag introduced by the thick protective wall.
Solution Approach 2:
The system replaces the mechanical/physical solution of thin-walled tubes with direct thermal contact by using a computational approach: multiple temperature measurements combined with heat flow analysis substitute for direct thermal coupling, achieving accurate measurements while maintaining the protective thick-walled structure.
4Ease of operation
If the process connection is located outside the container to allow access, then ease of installation and maintenance improve, but thermal equilibrium with environment causes heat flow and measurement error
Solution Approach 1:
The device performs preliminary detection of temperature at multiple locations (including at the process connection end) to establish the heat flow pattern before final temperature measurement is taken. This preliminary thermal characterization allows the system to pre-calculate correction factors that compensate for environmental thermal influences at the accessible process connection.
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 device accurately corrects installation errors and maintains high functional reliability by recognizing insulation damage and compensating for dynamic errors, ensuring precise temperature determination in a space-saving and economical manner.
Implementation Method 1
a resistance-based temperature sensor as a main sensor
Implementation Method 2
a thermoelectric-based temperature sensor as auxiliary sensor
Implementation Method 3
the heat flow runs from the base of the measuring tube to the process connection and causes a removal of heat from the temperature sensor
Data Source
AI summary
A device for determining the temperature of a medium in a tube or in a container is disclosed. The device includes a measuring tube protruding into the medium and closed at the end facing the medium by a measuring tube base, a resistance-based temperature sensor as a main sensor, and a thermoelectric voltage-based temperature sensor as an auxiliary sensor, arranged within the measuring tube at a fixed offset relative to the main sensor. The main sensor and the auxiliary sensor transmit measurement values to an analysis/transmitter unit. If the amount of a difference between the measurement values of the main sensor and the auxiliary sensor exceeds a first specified threshold, a fault notification relating to the integrity of the device is generated in the analysis/transmitter unit.