Looper-Less Long Product Rolling With Laser Speed Control

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Solution Overview

Problem

Long product mills face challenges in maintaining precise speed control between rolling mill stands due to inherent tension and compression issues, which are not fully addressed by existing minimum tension control systems and loopers, leading to inefficiencies and increased costs.

Innovation Solution

A looper-less rolling mill system utilizing laser velocimetry and camera arrangements to measure actual product speed and adjust rolling mill stand speeds, eliminating the need for mechanical loopers and associated control systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If loopers are utilized to control tension and speed differentials between rolling mill stands, then speed control stability is improved, but device complexity and equipment cost increase due to additional mechanical and electrical equipment

Engineering Contradiction:
Improvespeed control stabilityVSAvoidequipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the looper mechanism from the rolling mill system. Instead of using a physical looper to absorb speed differentials, the invention directly measures and controls the speed of each rolling stand independently, removing the need for the looper buffer zone and its associated mechanical and electrical equipment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical looper system with an optical measurement and electronic control system. Laser velocimeters measure the actual speed of the rolled material at each stand, and electronic controllers adjust motor speeds accordingly, substituting mechanical buffer zones with precision measurement and control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If loopers are used to compensate for speed errors between rolling mill stands, then process stability is improved, but manufacturing cost increases due to added equipment and increased mill length

Engineering Contradiction:
Improveprocess stabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent removes the looper infrastructure from the rolling mill design. By directly measuring material speed with laser velocimeters and controlling each stand's motor independently, the system eliminates the need for looper buffers, reducing both equipment costs and mill length while maintaining process stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system enables each rolling stand to self-regulate its speed based on real-time feedback from laser velocimeters. The electronic controllers continuously monitor actual material speed and automatically adjust motor speeds to maintain optimal processing conditions, eliminating the need for passive mechanical buffers.

Inventive Principle:
Principle #25Self-service

3Force

If minimum tension control systems are used to manage speed adjustments, then tension control is improved, but measurement precision of actual material speed deteriorates due to reliance on theoretical calculations

Engineering Contradiction:
Improvetension controlVSAvoidspeed measurement accuracy
Core Design Contradiction:
ForceVSMeasurement precision

Solution Approach 1:

The patent replaces theoretical speed calculations with direct optical measurement using laser velocimeters. The laser system measures the actual speed of the rolled material by detecting the velocity of reflected light, providing precise real-time speed data without relying on theoretical models or mechanical sensors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from theoretical calculation based on roll diameter and motor speed to direct optical measurement of material velocity. This parameter change enables accurate measurement of actual material speed, including any variations due to material spread, roll wear, or slip, providing true feedback for tension control.

Inventive Principle:
Principle #35Parameter changes

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

This approach improves speed control accuracy, reduces equipment costs, and enhances product quality by directly measuring and adjusting speed differentials between rolling mill stands, allowing for more precise control and reduced metallic yield loss.

Implementation Method 1

A looper is replaced with a simple laser velocimetry system and/or camera arrangement where one laser is positioned in-between each individual rolling mill stand

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 2

A looper is replaced with a simple laser velocimetry system and/or camera arrangement where one laser is positioned in-between each individual rolling mill stand

Methodology Applied
Scientific EffectPhotography: Photography

Data Source

PatentEP3720622B1Looper-less smart rolling in long product mills
Publication Date: 2023.03.22 PRIMETALS TECHNOLOGIES USA LLC
  • EP3720622B1 patent drawingFigure 1
  • EP3720622B1 patent drawingFigure 2

AI summary

A rolling mill for producing rolling mill product is provided. The rolling mill includes a rolling mill line that moves the rolling mill product. A plurality of rolling mill stands are coupled to the rolling mill line that receives the rolling mill product and rolls the rolling mill product. A plurality of speed measuring devices that are positioned in close proximity to each rolling mill stand, where each speed measuring device measures the speed of the rolling mill product as it passes the speed measuring devices. A control device receives information associated with the speed measuring devices and adjusts the speed of the rolling mill product for any speed differential that might exist between any of the rolling mill stands.