Rolling Mill Water Header Control for Stable Low-Flow Cooling
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Solution Overview
Problem
Existing cooling-water injection control methods for rolling mills face instability at low flow rates, leading to non-uniform water distribution and temperature variations, causing surface quality issues and rolling instability, due to variations in flow rate characteristics and mechanical deterioration of water injection headers.
Innovation Solution
A cooling-water injection control device and method that prioritize flow rate control for water injection headers, adjusting flow rates between minimum and maximum rates to maintain stable water injection, ensuring uniform cooling and minimizing the influence of header characteristic variations by controlling headers based on priority and transient flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the water injection amount of a water injection header is reduced below the minimum flow rate, then the total cooling capacity is reduced to match small water injection requirements, but the water distribution becomes non-uniform and spray stability is lost
Solution Approach 1:
The system segments the water injection function into multiple independent headers, each capable of being individually controlled. When total water injection requirement is small, only necessary headers are activated, ensuring each active header operates above minimum flow rate while achieving fine total flow control through selective header activation
Solution Approach 2:
The system dynamically selects which water injection headers to activate based on real-time cooling requirements. The control unit determines the minimum number of headers needed and activates them in a rotating sequence, allowing the system to adapt to varying water injection demands while maintaining stable operation of each activated header
2Quantity of substance
If multiple water injection headers are operated simultaneously at low individual flow rates, then the total cooling capacity is sufficient, but unstable phenomena occur due to small flow rates in each header
Solution Approach 1:
Instead of operating all headers simultaneously at low flow rates, the system dynamically activates only the necessary number of headers based on total cooling requirements. Each activated header operates at a stable flow rate above the minimum threshold, while inactive headers are completely shut off, eliminating unstable low-flow phenomena
Solution Approach 2:
The system uses partial action by activating only the minimum necessary number of headers required to meet the total water injection demand. This ensures that each activated header receives sufficient flow to operate stably, rather than distributing insufficient flow across all headers
3Reliability
If a flow rate regulation valve or on-off valve is used to force the flow rate to zero when below minimum flow rate, then spray stability is maintained, but the flow rate becomes non-adjustable and material temperature varies largely
Solution Approach 1:
The system segments the water injection control into discrete header-level on/off decisions rather than continuous flow rate adjustment. By controlling the number of active headers, the system achieves fine-grained control over total water injection amount while each active header maintains stable operation through binary valve control
Solution Approach 2:
The control unit dynamically determines the optimal number of headers to activate based on real-time cooling requirements. This dynamic selection provides fine adjustability in total water injection amount while each header operates in a stable on/off state, eliminating the need for flow rate regulation valves
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 the temperature of the material being rolled by averaging the influence of flow rate variations among multiple headers, reducing temperature fluctuations and maintaining surface quality, while allowing for fine adjustments in water injection amounts.
Implementation Method 1
Each of the water injection headers generally includes a large number of nozzles arranged in a width direction of the material to be rolled. Therefore, the cooling water can be sprayed to uniformly and efficiently cool the material to be rolled.
Data Source
AI summary
A cooling-water injection control device and a cooling-water injection control method for a rolling mill suppress influence by change in flow rate characteristics of water injection headers. The cooling-water injection control device for a rolling mill includes a water injection amount control unit. When a plurality of water injection headers are controlled to make temperature of a material to be rolled on a delivery side of a rolling mill coincident with a target value, in a case where a flow rate of any one of the plurality of water injection headers is less than a transient flow rate between a minimum flow rate and a maximum flow rate, the water injection amount control unit controls a flow rate of any one of the plurality of water injection headers based on priority.