SAW Temperature Sensor Wireless Measurement in High-Temperature Furnaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional temperature measurement methods using thermocouples face challenges in large or high-speed furnaces, where the heat resistance limitations of wireless units and storage devices hinder accurate temperature sensing, especially when the temperature exceeds the operational limits of batteries or storage devices.
Innovation Solution
A temperature sensor and measurement apparatus utilizing surface acoustic waves (SAW) on piezoelectric substrates, with comb-shaped electrodes and temperature detection reflectors, that wirelessly transmit and receive signals to calculate temperature changes without a power supply, using a composite piezoelectric body to deform and alter the surface acoustic wave path length based on an electromotive force, enabling accurate temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermocouple is connected to a wireless unit and introduced into a large furnace or high-speed furnace, then temperature measurement is enabled, but the battery serving as drive power source exceeds its heat resistance temperature and cannot be used
Solution Approach 1:
The patent extracts and removes the battery from the temperature sensor system, creating a passive SAW sensor that operates without power supply. The sensor uses only piezoelectric substrates, comb electrodes, and reflectors that function passively through acoustic wave propagation, eliminating the heat resistance limitation of batteries in high-temperature furnace environments
Solution Approach 2:
The patent replaces the electronic power supply system (battery) with a passive acoustic wave-based measurement system. The SAW sensor uses mechanical surface acoustic waves propagating on piezoelectric substrates to sense temperature, substituting the need for active electronic components and power sources with passive mechanical wave propagation that is inherently suitable for high-temperature environments
2Loss of information
If a data storage device is equipped in the wireless unit to store temperature information, then temperature data can be extracted after removal from furnace, but the storage device itself cannot withstand high temperatures
Solution Approach 1:
The patent removes the data storage device from the sensor system, creating a passive SAW sensor that measures and transmits temperature information through acoustic wave characteristics directly, without needing to store data in electronic memory that would fail at high temperatures
Solution Approach 2:
The patent replaces electronic data storage with passive acoustic wave-based information encoding. Temperature information is encoded in the characteristics of surface acoustic waves (frequency, propagation time) that can be measured directly, eliminating the need for electronic storage devices that cannot withstand furnace temperatures
3Measurement precision
If a thermocouple is used in a furnace with shutter present in conveyance path, then temperature measurement is attempted, but it is difficult to measure temperature in state where thermocouple is connected to measurer outside furnace
Solution Approach 1:
The patent merges the temperature sensor with the object being measured by forming the SAW sensor directly on or attached to the workpiece. The sensor travels with the workpiece through the entire furnace process including shutter operations, eliminating the need for separate measurement connections and enabling continuous temperature monitoring throughout the manufacturing process
Solution Approach 2:
The patent uses surface acoustic waves as an intermediary to transmit temperature information from the workpiece through the furnace environment to external measurement equipment. The acoustic waves propagate along the workpiece surface, passing through shutters and complex furnace geometries without requiring direct line-of-sight or physical connections to external measurers
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
Enables accurate temperature measurement of thermocouples in challenging environments by analyzing frequency characteristics and propagation time changes of surface acoustic waves, allowing for wireless and power-free temperature sensing, even in high-temperature conditions.
Implementation Method 1
a first piezoelectric substrate that propagates a surface acoustic wave
Implementation Method 2
a piezoelectric body that is joined to a back surface of a surface of the second piezoelectric substrate on which the second surface acoustic wave propagates, the piezoelectric body being configured to be deformed by an electromotive force of a thermocouple to change a path length of a propagation path of the second surface acoustic wave
Implementation Method 3
the piezoelectric body being configured to be deformed by an electromotive force of a thermocouple
Data Source
AI summary
As a temperature measurement apparatus using a surface acoustic wave of a piezoelectric substrate that performs temperature measurement wirelessly and without power supply, the temperature measurement apparatus accurately measures the temperature of the thermocouple tip end by analyzing the frequency characteristics of the surface acoustic wave propagating on the piezoelectric substrate and including temperature information of the piezoelectric substrate, and detecting change in propagation time of the surface acoustic wave of the piezoelectric substrate that is changed by the electromotive force of the thermocouple.