Rolling Mill Cooling Lines With Buffer Pressure Flow Control
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Solution Overview
Problem
Existing cooling systems in rolling mills face challenges with precise and dynamic control of coolant flow, leading to inefficiencies and inaccuracies in temperature control due to limitations in valve technology, such as pressure shocks, slow switching times, and inaccuracies in control valve positioning.
Innovation Solution
The implementation of a control device that dynamically adjusts both the control valve and an active device to manage a buffer area's pressure, allowing for a combination of base and additional flows to closely match target cooling currents, enabling rapid and precise control of coolant flow to hot rolling stocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If control valves are used to adjust coolant flow, then continuous adjustment is possible, but pressure shocks and slow switching times occur
Solution Approach 1:
The system segments the coolant flow control into two independent parts: a control valve for continuous base flow adjustment and a switching valve for rapid additional flow activation. This segmentation allows each component to optimize its function without compromising the other.
Solution Approach 2:
The system dynamically switches between base flow mode (control valve only) and additional flow mode (both valves open) based on real-time cooling demands. This dynamic operation enables fast response when rapid cooling is needed while maintaining continuous adjustability during normal operation.
2Speed
If switching valves are used for coolant control, then fast switching is achieved, but only binary control is possible
Solution Approach 1:
The system merges a switching valve (providing fast binary control) with a control valve (providing continuous adjustment) in parallel. The switching valve handles rapid on/off operations while the control valve provides fine-tuned flow modulation, combining the advantages of both valve types.
Solution Approach 2:
The system uses partial action by activating only the switching valve for minor adjustments and both valves together for rapid cooling. The additional flow from the switching valve supplements the base flow, providing enhanced control capability without requiring full binary operation.
3Ease of manufacture
If control flaps are used, then simple and inexpensive operation is achieved, but cavitation damage occurs at high pressure differences
Solution Approach 1:
The switching valve acts as an intermediary that handles the high-pressure differential operations, protecting the control flap from cavitation damage. The control flap continues to operate in its safe pressure range while the switching valve manages the additional flow under higher pressure differences.
Solution Approach 2:
The switching valve is designed to handle the harsh high-pressure conditions that would damage a control flap, effectively sacrificing the more expensive switching valve component protection to preserve the inexpensive control flap. This allows the use of simple, cheap control flaps for continuous adjustment while protecting them from cavitation.
4Stress or pressure
If ball valves are used, then higher pressure differences are tolerated, but hysteresis and cost increase
Solution Approach 1:
The system uses inexpensive control flaps for the continuous adjustment function where high pressure tolerance is not critical, and reserves the more expensive ball valves only for the switching function where high pressure differential is necessary. This selective application reduces overall system cost while maintaining necessary performance.
Solution Approach 2:
The system segments the pressure handling responsibilities: the control flap handles low-pressure differential continuous adjustment, while the ball valve handles high-pressure differential switching. This segmentation allows each component to be optimized for its specific pressure range, reducing overall system complexity and cost.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A cooling section (2) is arranged within a rolling mill or upstream or downstream of the rolling mill. Hot rolled metal stock (1) is cooled in this section. A control unit (13) of the cooling section (2) dynamically determines target control states (S1*) for control valves (10) arranged in supply lines (8) and controls the control valves (10) accordingly. Application units (6) of the cooling section (2) are supplied with base flows (F1) of a liquid, water-based coolant (7) via the supply lines (8) according to the control commands. The supply lines (8) deliver the base flows (F1) to buffer areas (12) of the application units (6). From there, cooling flows (F) of the coolant (7) are applied to the hot rolled metal stock (1). The control unit (13) also dynamically determines target control states (S2*) for active units (16) and controls the active units (16) accordingly.The active devices (16) supply the buffer zones (12) with additional flows (F2) of a further medium (18) via further supply lines (17), according to the control signal. The cooling flows (F) depend on both the base flows (F1) and the additional flows (F2). The additional flows (F2) are positive or negative depending on the control state (S2*) of the active devices (16). The control device (13) adjusts the additional flows (F2) by appropriately controlling the active devices (16) such that the cooling flows (F) are always as close as possible to the target flows (F*) of the coolant (7).