Cooling Bank Control for Stable Hot Rolling Temperature Patterns
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Solution Overview
Problem
In the context of hot rolling, the existing cooling pattern control methods, particularly in the second embodiment of PTL 1, fail to maintain the desired cooling pattern when feedforward control is performed in water-cooling banks located at the downstream side, leading to instability in temperature control and material quality.
Innovation Solution
A control device for a cooling apparatus that manages water injection amounts in multiple cooling banks, performing preset, feedforward, and feedback calculations to maintain the cooling pattern by allocating feedback banks downstream and feedforward banks upstream, with recalculation positions set to compensate for delays and adjust water injection based on actual and predicted temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If feedforward control is performed in water-cooling banks located at the downstream side, then temperature control responsiveness is improved, but the cooling pattern cannot be maintained
Solution Approach 1:
The cooling banks are segmented into two functional groups: feedforward control banks (upstream) and feedback control banks (downstream). This segmentation allows different control strategies to be applied to different sections, maintaining the overall cooling pattern while enabling responsive temperature control where needed.
Solution Approach 2:
Different control qualities are applied to different locations: feedforward control is applied upstream where the cooling pattern should be maintained, while feedback control is applied downstream where responsive temperature adjustment is prioritized. This local differentiation resolves the contradiction between pattern stability and control responsiveness.
2Measurement precision
If feedback control is performed in water-cooling banks, then temperature accuracy is improved, but response delay occurs due to conveyance time
Solution Approach 1:
Feedforward control performs preliminary temperature adjustment upstream before the material reaches the feedback control section. This preliminary action compensates for predicted temperature deviations, reducing the burden on feedback control and minimizing the effective response delay.
Solution Approach 2:
The feedforward control banks act as an intermediary between the cooling pattern requirement and the feedback control system. They pre-adjust the material temperature based on predicted deviations, serving as a buffer that reduces the impact of conveyance delay on the overall temperature control accuracy.
3Adaptability or versatility
If water injection amounts are changed to compensate for speed deviation, then temperature control flexibility is improved, but the cooling pattern becomes unstable
Solution Approach 1:
The control system is segmented into feedforward banks that maintain the cooling pattern and feedback banks that provide flexible temperature adjustment. This segmentation allows water injection amounts to be changed for speed compensation in the feedback section without destabilizing the overall cooling pattern established by the feedforward section.
Solution Approach 2:
Different control flexibilities are applied locally: the feedforward section maintains a stable, predetermined cooling pattern, while the feedback section provides flexible, adaptive temperature control. This local differentiation enables overall system flexibility without compromising pattern stability.
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 stabilizes temperature control across varying rolling speeds, maintains the cooling pattern, and ensures the material reaches the target temperature at the delivery side, enhancing the quality of the rolled material.
Implementation Method 1
a plurality of cooling banks 12 that cool the material to be rolled M
Implementation Method 2
water injection amounts in the plurality of cooling banks
Data Source
AI summary
In preset calculation, a plurality of cooling banks are set to be feedforward or feedback banks, and each of water injection amounts in these banks is calculated. In cooling history management, a recalculation position for re-executing the feedback calculation is set. In feedback calculation, a temperature correction value for compensating a delay due to a conveyance time period from a position of the feedback bank to a position of a delivery side pyrometer, and a response delay of the feedback bank is calculated, when a segment reaches the recalculation position. In the feedback calculation, each of water injection amounts in the feedback banks that is calculated in the preset calculation is changed for each of segments based on a delivery side temperature target value, a delivery side temperature actual value calculated for each of the segments, a delivery side temperature prediction value that is recalculated, and the temperature correction value.