Microwave Probe for Refractory Thickness Measurement
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Solution Overview
Problem
Current methods for evaluating the condition of refractory materials in large furnaces, such as those in the glass and steel industries, face challenges in determining thickness and detecting internal defects due to signal loss and spurious reflections when using microwave radiation, leading to costly and potentially dangerous maintenance shutdowns.
Innovation Solution
A system and method utilizing low-frequency microwave bands with an antenna configuration that creates a time delay between spurious and actual reflections, combined with impedance matching to suppress unwanted signals, allowing for remote evaluation of refractory material thickness and defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If microwave radiation is used to evaluate refractory material thickness, then non-contact measurement capability is improved, but signal loss increases making measurement difficult
Solution Approach 1:
The patent changes the microwave frequency parameter to lower bands (e.g., L-band 1-2 GHz, C-band 4-8 GHz) to reduce signal loss in refractory materials while maintaining non-contact measurement capability. This parameter optimization allows penetration through thick refractory walls with sufficient signal return for accurate thickness measurement.
Solution Approach 2:
The patent introduces an intermediary time delay mechanism through specific antenna configuration that separates the desired reflected signal from spurious reflections. This allows the measurement system to distinguish and process only the relevant signal components, effectively reducing noise and improving measurement accuracy despite signal loss.
2Measurement precision
If system components are placed close to the surface for measurement, then measurement precision is improved, but spurious signal reflections increase complicating signal isolation
Solution Approach 1:
The patent converts the harmful spurious reflections into a manageable problem by using their predictable timing characteristics. Through time delay analysis and signal processing, the system identifies and isolates the first strong reflection (spurious) from the second reflection (desired thickness measurement), effectively using the harmful reflection as a reference point for extracting useful measurement data.
Solution Approach 2:
The patent extracts and isolates the desired reflected signal from the mixture of spurious reflections and useful echoes through signal processing techniques. By separating the second reflection component from the total received signal, the system obtains pure thickness measurement data free from contamination by near-field spurious reflections.
3Reliability
If furnace walls are replaced based on lifetime estimates, then operational safety is improved, but production disruption and cost increase
Solution Approach 1:
The patent replaces mechanical inspection methods (shutdown, physical measurement, visual inspection) with electromagnetic wave-based remote sensing. Microwave radar enables non-contact, non-intrusive thickness measurement through the refractory wall, eliminating the need for production shutdown and providing continuous monitoring capability for timely maintenance scheduling.
Solution Approach 2:
The patent enables the refractory wall to 'self-report' its thickness and condition through microwave reflection characteristics. The measurement system passively receives reflected signals that contain information about wall integrity, eliminating the need for active intervention or shutdown to assess wall condition, thus maintaining continuous production.
4Measurement precision
If high frequency microwave bands are used, then wavelength resolution is improved, but signal penetration and loss characteristics worsen
Solution Approach 1:
The patent optimizes the microwave frequency parameter by selecting lower frequency bands (L-band 1-2 GHz, C-band 4-8 GHz) that provide adequate signal penetration through thick refractory materials. While lower frequencies provide coarser wavelength resolution, the improved penetration and reduced signal loss enable successful measurement through the entire refractory wall thickness, which is the primary measurement challenge.
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 thickness measurement and defect characterization of refractory materials, both in cold and hot states, reducing maintenance costs and ensuring safer operations by isolating the signal of interest and compensating for temperature-dependent dielectric properties.
Implementation Method 1
A plurality of antennae are provided in a probe assembly. The antennae are configured to transmit a microwave signal through the refractory material
Implementation Method 2
the signal processing module is configured to process the reflected signal to determine the thickness of the refractory material
Implementation Method 3
utilizing a system configuration and signal processing techniques that isolate the reflected signal of interest from other spurious antenna reflections, particularly by creating (through the configuration of the antenna assembly) a time delay between such spurious reflections and the actual reflected signal of interest
Implementation Method 4
the antenna assembly is intrinsically matched to the material to be probed, such as by impedance matching the antenna to the particular material (through knowledge of the dielectric and magnetic properties of the material to be evaluated) to even further suppress spurious reflections
Implementation Method 5
through knowledge of the dielectric and magnetic properties of the material to be evaluated
Data Source
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AI summary
A method and system for evaluating the condition of a remote surface of a material, especially a refractory material, including the steps of providing a wide band coherent radar antenna that is selected based upon an impedance match with the material to be evaluated, wherein said antenna is provided a physical configuration adapted to delay receipt of a signal of interest reflected from said remote surface of said material by a time period sufficient to distinguish between said reflected signal of interest and reflected spurious signals from a near surface of said material, placing said antenna adjacent said near surface of said material, irradiating said material with coherent microwave radiation tuned over a frequency range, detecting reflected microwave radiation from said remote surface of said material, and determining the thickness of the material based upon a determined distance traveled by said signal of interest.