Tension Adjustment Device for Mill Vibration Control
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Solution Overview
Problem
High-speed metal rolling mills experience self-excited third octave vibrations, which can damage the mill and rolled metal, and existing methods to counter these vibrations either cause wear or significantly slow down the rolling process.
Innovation Solution
A system comprising a tension adjustment device, such as a center bridle roll or actuated deflection roll, and a control system that varies the vertical placement of the device in response to inter-stand strip tension disturbances within the frequency range of 90-300 hertz, using hydraulic cylinders and piezoelectric actuators to maintain constant strip tension and prevent self-excited vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rolling speed is reduced to counter self-excited third octave vibration, then vibration damage is reduced, but productivity significantly decreases
Solution Approach 1:
The patent applies dynamics by making the tension adjustment device movable and adjustable in real-time. The device transitions from a static configuration to a dynamic one where the vertical position can be continuously modified during rolling operations to counteract vibrations at different frequencies and amplitudes, thereby maintaining productivity while preventing damage
Solution Approach 2:
The patent changes physical parameters by adjusting the vertical position of the tension adjustment device to modify the tension applied to the metal strip. This parameter change allows the system to counteract self-excited vibrations without reducing rolling speed, thus maintaining productivity while protecting the mill stand
2Reliability
If tension adjustment device is added to control vibrations, then self-excited vibrations are mitigated, but device complexity increases
Solution Approach 1:
The tension adjustment device is designed to perform multiple functions: it adjusts strip tension during rolling operations and simultaneously counteracts self-excited third octave vibrations. This multi-functionality reduces the need for separate dedicated vibration control devices, thereby limiting the increase in overall device complexity
Solution Approach 2:
The patent introduces a tension adjustment device as an intermediary element between the rolling mill stands. This device mediates the interaction between the mill stand and the metal strip by applying controlled tension variations, thereby counteracting vibrations without requiring direct modification of the mill stand structure itself
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
Effectively mitigates self-excited third octave vibrations, reducing damage and allowing for faster, more efficient metal rolling without the need for significant energy or mechanical modifications to the mill.
Implementation Method 1
using hydraulic cylinders and piezoelectric actuators to maintain constant strip tension
Implementation Method 2
using hydraulic cylinders and piezoelectric actuators to maintain constant strip tension
Implementation Method 3
a sensor for measuring tension fluctuations at or above 90 hertz of the metal strip entering the mill stand
Data Source
Figure 1
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AI summary
Control of self-excited third octave vibration in a metal rolling mill can be achieved by adjusting the tension of the metal strip as it enters a stand 102. Self-excited third octave vibration can be detected and/or measured by one or more sensors. A high-speed tension adjustor 144 can rapidly adjust the entry tension of the metal strip (e.g., as the metal strip enters a mill stand) to compensate for the detected self-excited third octave vibration. High-speed tension adjustors can include any combination of hydraulic or piezoelectric actuators coupled to the center roll of a bridle roll to rapidly raise or lower the roll and thus induce rapid tension adjustments in the strip. Other high-speed tension adjustors can be used.