Rolling Mill Conveyor Speed Control for Coil Stability
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Solution Overview
Problem
Conventional rolling mills face issues with coil distortion and reduced mill utilization due to the need to temporarily accumulate product above the reforming chamber and maintain a 5-second gap between billets, leading to unstable coils and lost production time.
Innovation Solution
The conveyor system is subdivided into sections with adjustable speeds to manage the flow of rings, allowing for a controlled time gap between billet lengths by varying the speed of ring transport along different sections, enabling efficient delivery to the reforming station without temporary accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rings are temporarily accumulated above the reforming chamber to clear completed coils, then coil formation can be completed, but coil distortion occurs and mill utilization time is lost
Solution Approach 1:
The conveyor system uses variable speed control across different sections to dynamically adjust ring transport rates. The first conveyor section operates at a first speed while succeeding sections operate at a second speed, creating a controlled time gap that eliminates the need for temporary accumulation and prevents coil distortion while maintaining continuous operation
Solution Approach 2:
The conveyor system is divided into multiple independently controlled sections with different speed settings. This segmentation allows different parts of the ring stream to be processed at different rates, enabling the tail end of one billet to clear the first section while the head of the next billet is already positioned, eliminating idle time
2Ease of operation
If a 5 second gap is maintained between billets, then reforming chamber clearing is possible, but mill utilization decreases by up to 10%
Solution Approach 1:
The system prepares the next billet for processing by positioning it on the conveyor while the previous billet is still being cleared from the reforming chamber. The variable speed control allows the head of the next billet to advance to the ready position before the reforming chamber is fully cleared, eliminating the 5-second gap and increasing mill utilization by up to 10%
3Productivity
If rings are dropped into the reforming chamber at the beginning of each coil forming cycle, then continuous production is maintained, but the coil base is distorted resulting in unstable coils
Solution Approach 1:
By dynamically controlling the speed of different conveyor sections, the system delivers rings to the reforming chamber at a controlled rate that matches the coil formation process. This prevents the harmful effect of dropping rings at the beginning of each cycle while maintaining continuous production flow
Data Source
AI summary
In a rolling mill in which hot rolled product is formed into rings by a laying head and the rings are transported in an overlapping pattern to a reforming station where the rings are gathered into coils, a method of increasing the time gap between billet lengths of product delivered to the reforming station by advancing the rings of a front end of one billet along said conveyor at a one speed while advancing the rings of a tail end of a preceding billet at another speed greater than said one speed.