Rolling Mill Work Roll Synchronization via Vertical Thrust
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Solution Overview
Problem
Rolling mills face frequent downtime and reduced productivity due to the need for frequent changes of work rolls, especially in multi-roll stands like 18-High, where maintaining contact and controlling rotation without slippage is challenging, leading to wear, cracking, and surface damage, particularly with stainless steel and high elastic limit materials.
Innovation Solution
A device that applies vertical thrust forces using elevator modules with rollers or pads to synchronize the rotation speed of work rolls with the moving strip, ensuring controlled docking and rotation without slippage, and allowing for on-the-fly roll changes in multi-stand rolling mills.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If work rolls are frequently changed to maintain rolling quality, then product quality is improved, but productivity deteriorates due to repeated stopping and starting of the rolling operation
Solution Approach 1:
The device prepares the standby work roll in advance by pre-synchronizing its rotational speed with the moving strip speed before the actual roll change. This preliminary preparation ensures that when the roll change occurs, the standby roll is already ready to immediately take over without causing stopping or speed variations, thus maintaining both quality and productivity
2Measurement precision
If the working roll is accelerated or decelerated to match strip speed during roll change, then docking precision is improved, but slippage occurs between the intermediate cylinder and working roll
Solution Approach 1:
The device applies a vertical thrust force through the thrust means that counteracts the frictional forces between the intermediate cylinder and working roll during speed adjustment. This additional force prevents slippage by ensuring sufficient contact pressure is maintained even when the working roll is being accelerated or decelerated to match the strip speed, thus achieving both precise docking and reliable rotation control
Solution Approach 2:
The thrust means utilizes pneumatic or hydraulic mechanisms to generate and apply vertical thrust forces to the working roll. This allows precise control of the contact force between the intermediate cylinder and working roll during speed synchronization, enabling reliable rotation control while achieving accurate docking with the moving strip
3Adaptability or versatility
If the working roll diameter is reduced to handle thin strip materials, then adaptability is improved, but the roll cannot withstand sufficient rolling torques under high elastic limit materials
Solution Approach 1:
The device employs a multi-roll configuration where smaller diameter working rolls are nested within a system that includes intermediate rolls and support rolls. The smaller working rolls can handle thin strip materials effectively, while the larger intermediate and support rolls provide the necessary structural strength and torque transmission capability, thus achieving both adaptability to thin materials and sufficient rolling torque capacity
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 solution enables continuous rolling operations within tight tolerances, minimizing slippage and surface defects, thereby improving productivity and product quality by maintaining consistent rolling conditions and reducing the need for frequent stops during roll changes.
Implementation Method 1
a lower intermediate roll (IRI) driving in rotation by surface contact and friction a lower work roll (WRI)
Data Source
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AI summary
The device has a set of lower laminating rolls comprising a lower intermediate roll (IRI) rotating a lower working roll (WRI) by surface and frictional contact. Upper laminating rolls include an upper intermediate roll (IRS) rotating an upper working roll (WRS) by the contact. The working rolls are in contact with a lower or an upper face of a strip (B) to be rolled. A vertical push unit formed by rollers or pulleys (R1i, R2i), support pads and arms (EI, EI') exerts force downward on the lower working roll before the lower working roll contacts the strip for active rolling positions. An independent claim is also included for a method for changing working rolls arranged in stands of a rolling mill.