Electromagnetic Hot Rolling Gauge for Tube Diameter and Wall Thickness
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Solution Overview
Problem
Existing methods for measuring the transverse size of metal profiles during hot rolling, such as steel bars or tubes, face challenges including deviations in thickness due to mandrel eccentricity and localized thickness variations, and are hindered by high costs, safety concerns, and sensitivity to material conductivity and temperature in non-ferrous metals.
Innovation Solution
A method using a sinusoidal current with multiple frequencies to power a transmission element generating an electromagnetic field with a specific profile, allowing for precise measurement of diameter and thickness through a reception element positioned optimally to detect electromagnetic field variations, independent of the metal profile's position, conductivity, and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radioactive sources and radiation detectors are used to measure thickness, then measurement capability is provided, but high costs and safety problems arise
Solution Approach 1:
The patent replaces the radioactive measurement system with an electromagnetic induction system using transmission and reception coils. This substitution eliminates the harmful effects of radioactive materials while maintaining the ability to measure thickness through electromagnetic field interaction with the metal profile
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary between the measurement device and the metal profile. The transmission coil generates an electromagnetic field that induces currents in the profile, and the reception coil detects these currents to determine thickness, providing a safe and cost-effective measurement method
2Measurement precision
If ultrasonic laser technology is used with angular scan to measure thickness, then measurement capability is provided, but device complexity and maintenance difficulty increase
Solution Approach 1:
The patent extracts the essential measurement function from the complex ultrasonic laser system with angular scan mechanisms. By using simple transmission and reception coils positioned on opposite sides of the profile, it achieves thickness measurement without requiring complex mechanical scanning or rotation systems
Solution Approach 2:
The patent replaces the mechanical angular scan system with a stationary electromagnetic field system. The coils remain fixed in position while the metal profile moves through the measurement zone, eliminating the need for complex mechanical movement and rotation mechanisms
3Measurement precision
If electromagnetic devices with parasitic currents are used, then measurement capability is provided, but measurement accuracy deteriorates due to dependence on material conductivity and temperature
Solution Approach 1:
The patent divides the electromagnetic measurement system into separate transmission and reception coils. This segmentation allows the transmission coil to generate the electromagnetic field while the reception coil independently detects the induced currents, enabling differential measurement that compensates for variations in material conductivity and temperature
Solution Approach 2:
The patent implements a measurement system where the reception coil detects changes in electromagnetic field caused by the metal profile's position and dimensions. The system uses this feedback to calculate transverse size while compensating for material property variations through the differential measurement approach
4Measurement precision
If single-frequency electromagnetic measurement is used, then measurement capability is provided, but measurement precision deteriorates for hot metal profiles
Solution Approach 1:
The patent uses periodic alternating current at multiple frequencies to excite the transmission coil. This periodic action at different frequencies allows the system to distinguish between signals caused by the metal profile's dimensions and those caused by temperature-induced conductivity changes, improving measurement precision for hot profiles
Solution Approach 2:
The patent changes the frequency parameter of the electromagnetic excitation to optimize measurement for hot metal profiles. By using multiple frequencies, the system can select the optimal frequency range that minimizes the impact of temperature on measurement accuracy
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 reliable, precise, and simultaneous measurement of external diameter and mean/local thicknesses of metal profiles, independent of alignment and material properties, improving the quality and performance of metal profiles by correcting for eccentricity and thickness deviations.
Implementation Method 1
power with a sinusoidal current having at least two frequencies, a transmission element having at least two sections distinct and spatially separated from each other... and generating with the transmission element an electromagnetic field with a desired profile of the force lines
Implementation Method 2
detect a signal relating to the variations of the electromagnetic field induced by the passage of the metal profile through the sections of the transmission element by means of a reception element
Data Source
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AI summary
Method and device for the hot measuring, during rolling, of a transverse size of a metal profile (12) such as a tube or a solid bar, to obtain at least the measurement of a diameter (D) and/or an mean thickness (SI) of said metal profile (12). The method provides to power with a sinusoidal current (20) having at least two frequencies (F1, F2), a transmission element (14) having at least two sections (14a, 14b, 14c, 14d) distinct and spatially separated from each other and disposed along a nominal axis of feed (Z) of the metal profile (12), generating with said transmission element (14) an electromagnetic field with a desired profile of the force lines, and detecting a signal (22) relating to the variations of said electromagnetic field due to the passage of said metal profile (12) through said sections (14a, 14b, 14c, 14d) of said transmission element (14) by means of a reception element (18) having one or more sections (18a, 18b) distinct and spatially separated from each other and disposed along said nominal axis (Z) in a position comprised in the overall longitudinal bulk of said transmission element (14).