Hybrid Work Roll Cooling Layout for Flatness and Heat Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing metal rolling processes face challenges with high heat in work rolls leading to undesirable strip flatness, low productivity, and fire risks, particularly due to the limitations of oil-cooled systems and the expense and complexity of water-cooled mills, which can cause surface defects and require costly containment systems.
Innovation Solution
A hybrid cooling system is introduced, where water cooling is applied to the bottom roll on the exit side and oil cooling to the top and bottom rolls on the entry side, with the option to divert excess oil from the bottom roll to the top roll, allowing for efficient heat management without the need for complex water containment systems above the pass line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water cooling is used to cool work rolls, then heat removal capability is improved, but device complexity and cost increase due to containment systems
Solution Approach 1:
The cooling system is segmented into two distinct zones: water cooling is applied only to the bottom work roll at the exit side where high heat removal is needed, while oil cooling is used for the top work roll and entry side. This segmentation allows the system to achieve effective cooling without requiring water containment systems throughout the entire rolling mill, thereby reducing device complexity while maintaining temperature control
Solution Approach 2:
Different cooling methods are applied to different locations based on specific needs: water cooling (high heat removal) is localized to the bottom roll exit side where heat generation is highest, while oil cooling (lower heat removal but lubrication capability) is used for the top roll and entry side. This local quality approach optimizes cooling efficiency without requiring expensive water containment infrastructure throughout the mill
2Productivity
If water cooling is used to cool work rolls, then productivity is improved, but surface defects occur due to water dripping on strips
Solution Approach 1:
The system segments the cooling application zones so that water cooling is restricted to the bottom work roll at the exit side, away from the strip path. The top work roll and entry side use oil cooling. This segmentation prevents water from dripping onto the strip while maintaining high productivity through effective water cooling where needed
Solution Approach 2:
Oil acts as an intermediary cooling and lubricating medium for the top work roll and entry side where the strip passes. It provides sufficient cooling for these zones without the fire risk and surface defect problems associated with water, while water serves as the primary cooling medium for the bottom roll exit side where heat removal is most critical but strip contact is avoided
3Reliability
If oil cooling is used to cool work rolls, then fire risk is reduced, but heat removal capability is insufficient
Solution Approach 1:
The system applies different cooling qualities to different locations: oil cooling (fire-safe but lower heat removal) is used for the top work roll and entry side, while water cooling (high heat removal but flammable) is used for the bottom work roll exit side. This local quality differentiation maintains fire safety where water is not needed while achieving sufficient heat removal where water is applied
Solution Approach 2:
The system merges oil cooling and water cooling into a hybrid system that combines the advantages of both: oil provides fire-safe cooling and lubrication for the top roll and entry side, while water provides high heat removal capability for the bottom roll exit side. This combination achieves both fire safety and effective heat removal that neither system could achieve alone
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 enhances productivity and flatness control, reduces the risk of fires, and lowers costs by leveraging the benefits of water-cooled rolling while eliminating the need for expensive water containment equipment, allowing for efficient cooling and lubrication of both soft and hard metals.
Implementation Method 1
water cooling is applied to the bottom roll on the exit side
Implementation Method 2
oil cooling is applied on the entry side to the top and bottom rolls
Implementation Method 3
During the rolling process, the work rolls are commonly cooled with oil, and can become very hot
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A rolling mill (100) with oil-cooled top and bottom work rolls (102, 104) at the entry side (124) and a water spray header (130) at the exit side (126) of the bottom work roll (104). Water cooling is used below the pass line (128), reducing the heat in the mill (100) substantially without the risk of generating drip-related surface defects during rolling. Water cooling can be used on the bottom work roll (104) and a portion of the oil no longer needed to cool the bottom work (104) roll can be diverted to the top work roll (102). In some cases, the coolant portion of the flatness control can be operated solely through water-cooling the bottom roll (104).