Rolling Mill Cooling Pressure Control for Target Flow at Minimum Pressure
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Solution Overview
Problem
Conventional cooling devices for hot metal rolling stock often operate at higher energy consumption due to constant high working pressures, which can be inefficient and costly, while still requiring precise control to maintain target coolant flows.
Innovation Solution
An operating method for a cooling device that determines individual working pressures for each control valve and adjusts the pump arrangement to maintain the lowest possible final working pressure, ensuring target coolant flows are met with reduced energy consumption by optimizing the control state of the pump arrangement and valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant high working pressure is used in the cooling device, then the coolant flow to application devices is maintained, but energy consumption increases significantly
Solution Approach 1:
The pump arrangement operates dynamically by switching between multiple operational states (first state with higher pressure for filling, second state with lower pressure for maintenance) based on the actual cooling needs and manifold pressure levels, rather than maintaining constant high pressure throughout operation
Solution Approach 2:
The system changes the operating pressure parameter over time by transitioning between different pump operational states, adjusting the pressure according to the filling phase and maintenance phase requirements, thereby reducing energy consumption while maintaining cooling effectiveness
2Reliability
If the pump arrangement operates at high pressure continuously, then coolant delivery is ensured, but wear and mechanical stress on pumps and control valves increase
Solution Approach 1:
The control device dynamically adjusts pump operational states based on manifold pressure feedback, reducing the duration of high-stress operation and allowing components to operate at lower stresses during maintenance phases, thereby extending component lifespan
Solution Approach 2:
The system employs periodic switching between filling operations (high pressure) and maintenance operations (low pressure), creating a cyclical operation pattern that reduces cumulative mechanical stress and wear on pumps and control valves
3Manufacturing precision
If high working pressure is maintained in the manifold, then target coolant flows are achieved, but energy efficiency decreases
Solution Approach 1:
The control device monitors manifold pressure and uses this feedback to determine when to switch between pump operational states, ensuring high pressure is maintained only when necessary for filling, and transitioning to low pressure when target flows are achieved, thereby improving energy efficiency
Solution Approach 2:
The system changes the pressure parameter dynamically based on operational phase and feedback signals, maintaining high pressure only during filling operations and reducing to low pressure during maintenance operations, optimizing the balance between flow accuracy and energy efficiency
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 reduces energy consumption by up to 80% compared to constant pressure operation, maintaining efficient cooling without adverse effects on the rolling stock, while protecting the mechanics of control valves and pumps by operating them at lower speeds and higher openness.
Implementation Method 1
a pump arrangement (5) by means of which the liquid coolant (6) is fed into the manifold (4)
Implementation Method 2
a control valve (11a to 11d) is arranged in each of the branch lines (9a to 9d)
Implementation Method 3
a cooling device for cooling a hot rolled metal product
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A liquid coolant (6) is fed into a manifold (4) via a pump assembly (5). Branch lines (9a to 9d), in which control valves (11a to 11d) are arranged, extend from the manifold (4) to application devices (10a to 10d). The coolant (6) is applied to a hot rolled metal workpiece (2) by means of the application devices (10a to 10d), thus cooling the workpiece (2). A control unit (12) of the cooling unit (3) determines, based on the target flow rates (Ka* to Kd) of the application devices (10a to 10d) and the limit values (kLim) of the control valves (11a to 11d), individual operating pressures (pAa to pAd) that must prevail in the manifold (4) so that the target flow rates (Ka* to Kd*) flow in the branch lines (9a to 9d).It then determines a preliminary control state (Z) of the pump arrangement (5) such that the sum of the target flows (Ka* to Kd*) is supplied to the manifold (4) and simultaneously a preliminary operating pressure (pAv) prevails in the manifold (4) that corresponds at least to the highest individual operating pressure (pAa to pAd). Using the preliminary control state (Z), it determines a final control state (Z') of the pump arrangement (5) such that the total flow (K) is supplied to the manifold (4) and simultaneously a final operating pressure (pAe) prevails in the manifold (4). It then determines, using the final operating pressure (pAe), control values (Aa to Ad) of the control valves (11a to 11d) so that the target flows (Ka* to Kd*) flow in the branch lines (9a to 9d). It controls the pump arrangement (5) and the control valves (11a to 11d) accordingly.