Terahertz Strand Wall Thickness Measurement
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Solution Overview
Problem
Existing ultrasonic and terahertz measuring devices face challenges in accurately measuring the wall thickness and diameter of cylindrical strands due to dependencies on contact mediums, temperature, and complexities in handling variable diameters and multiple reflections, particularly for foamed or partially foamed products and transparent strands.
Innovation Solution
A terahertz measurement device with a guide mechanism that aligns the terahertz radiation perpendicular to the strand's longitudinal axis, utilizing a reflector to separate and amplify measurement signals, and an evaluation device that determines transit times to calculate wall thickness and diameter independently of material properties, allowing for reliable measurements without adjustments for different diameters or material compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic measuring devices are used to measure wall thickness, then measurement can be performed on strand-like goods, but the strand must be in contact with a contact medium (usually water) whose density, temperature and quality strongly influence the measurement result
Solution Approach 1:
The patent uses air as an intermediary medium instead of water, eliminating the need for complex contact medium control systems. The terahertz radiation propagates through air to measure the wall thickness, removing dependencies on water density, temperature, and quality while maintaining measurement capability.
Solution Approach 2:
The patent replaces the mechanical contact-based ultrasonic measurement system with a non-contact terahertz radiation system. This substitution eliminates the need for physical contact with the measured object and removes all associated requirements for contact mediums, temperature control, and quality management.
2Measurement precision
If known terahertz measuring devices are used to measure flat products, then distance or wall thickness measurement is comparatively simple, but for cylindrical strand products the sensor would have to be tracked for optimal focusing on the surface of the strand
Solution Approach 1:
The patent adapts the measurement system for cylindrical geometry by using a curved reflector that matches the curvature of the strand. This allows the terahertz radiation to be properly focused on the cylindrical surface without requiring complex sensor tracking mechanisms, as the curved reflector automatically compensates for the geometry.
Solution Approach 2:
The patent pre-configures the reflector with the appropriate curvature before measurement begins. This preliminary setup eliminates the need for real-time sensor tracking and adjustment during measurement, as the geometric configuration is already optimized for cylindrical strands.
3Measurement precision
If terahertz radiation is used to measure transparent strands, then measurement is possible, but algorithms for evaluating the measurement signals have to be readjusted for each radius of curvature and multiple reflections complicate the evaluation
Solution Approach 1:
The patent uses a curved reflector that matches the strand's radius of curvature, which geometrically corrects the measurement paths of terahertz radiation. This eliminates the need to readjust algorithms for different curvatures, as the curved reflector automatically adapts to any radius of curvature of the strand being measured.
Solution Approach 2:
The patent extracts and separates the multiple reflection components using the curved reflector geometry, which directs reflected rays in predictable patterns. This allows the evaluation algorithm to clearly distinguish between direct transmission signals and multiple reflections, simplifying the evaluation process for transparent strands.
4Measurement precision
If ultrasonic measuring devices are used, then wall thickness can be measured, but measurement results are dependent on the temperature of the strand, in particular the wall thickness to be measured
Solution Approach 1:
The patent replaces the ultrasonic measurement system with a terahertz radiation system that does not depend on the mechanical properties of the material being measured. Terahertz radiation measurements are not influenced by the temperature of the strand, eliminating the temperature dependency problem inherent in ultrasonic methods.
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 solution enables precise and efficient measurement of wall thickness and diameter of circular cylindrical strands with reduced influence from external parameters, minimizing errors and maintaining accuracy across varying diameters and unknown material compositions.
Implementation Method 1
The at least one transmitter emits terahertz radiation, which is correspondingly received by the at least one receiver
Implementation Method 2
a reflector for the terahertz radiation is arranged opposite at least one transmitter in the radiation direction of the terahertz radiation emitted by the transmitter behind the strand
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a device for measuring the diameter and/or the wall thickness of a strand, which is substantially circular in cross-section and which is guided through the device in the direction of the longitudinal axis of the strand by means of guiding means, comprising at least one transmitter for emitting terahertz radiation, wherein at least one radiation optical unit is provided, which conducts terahertz radiation emitted by the transmitter to a strand guided through the device, wherein a reflector for the terahertz radiation is arranged opposite at least one transmitter and is arranged behind the strand in the radiation direction of the terahertz radiation emitted by the at least one transmitter, and also comprising at least one receiver for receiving the tetahertz radiation emitted by the at least one transmitter and reflected on the strand and/or on the reflector, and comprising an evaluating apparatus, which is designed to determine the diameter and/or the wall thickness of the strand on the basis of the measurement signals received by the at least one receiver. The invention further relates to a corresponding method.