Rolling Mill Cooling Section with Variable-Speed Pump Flow Control
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Solution Overview
Problem
Current cooling systems in rolling mills face inefficiencies due to pressure shocks, slow switching times, flow losses, and high energy consumption, particularly with on-off and control valves, which hinder precise temperature control and lead to increased wear and maintenance needs.
Innovation Solution
A cooling system utilizing variable-speed pumps controlled by a frequency converter, eliminating the need for valves and enabling rapid and precise adjustment of coolant flow, with optional shutoff devices and return lines to manage flow rates, and incorporating check valves to prevent pump dry-running.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If control valves are used to adjust coolant flow, then flow quantity can be continuously adjusted, but switching time is slow and pressure shocks occur
Solution Approach 1:
The patent removes valves entirely from the coolant supply system and extracts only the necessary function of flow control, which is achieved by independently controlling multiple pumps to deliver precise flow quantities without requiring any valve components.
Solution Approach 2:
The system uses dynamically controllable pumps with variable speed drives that can rapidly adjust their rotation speeds to change coolant flow quantities instantly, eliminating the slow mechanical adjustment of traditional control valves and achieving switching times under 0.2 seconds.
2Ease of operation
If on-off valves are used to control coolant flow, then flow can be switched, but switching time exceeds 1 second and pressure shocks occur
Solution Approach 1:
The patent eliminates on-off valves from the system and extracts only the essential function of flow on/off control, achieving this by simply stopping or starting the respective pumps, which eliminates mechanical valve components and reduces switching time to under 0.2 seconds.
Solution Approach 2:
The patent replaces the mechanical valve opening/closing mechanism with an electrical control system that directly actuates the pumps, substituting mechanical motion with electrical control signals to achieve faster and shock-free flow switching.
3Device complexity
If control flaps are used to adjust coolant flow, then flow can be controlled with simple structure, but cavitation occurs at pressure differences above 1 bar
Solution Approach 1:
The patent removes control flaps and all valve components from the system, extracting only the necessary flow control function which is achieved by independently controlling multiple pumps, thereby eliminating cavitation-prone mechanical components entirely.
Solution Approach 2:
The system uses hydraulic pumps with variable speed drives to control coolant flow, replacing the pneumatic/control flap mechanism with a hydraulic system that can handle high pressure differences without cavitation by directly controlling pump output rather than restricting flow through orifices.
4Measurement precision
If ball valves are used to control coolant flow, then hysteresis is eliminated, but valve cost increases significantly
Solution Approach 1:
The patent eliminates ball valves and all valve components from the system, extracting only the necessary flow control function through independent pump control, thereby achieving precise flow adjustment without the high cost of ball valves.
Solution Approach 2:
The patent replaces expensive mechanical ball valves with an electrical control system using variable speed pump drives, substituting mechanical flow restriction with electrical control of pump output, achieving the same precision at lower cost.
5Adaptability or versatility
If valves are used to adjust coolant flow, then flow control is achieved, but flow losses and energy consumption increase
Solution Approach 1:
The patent removes valves from the system and extracts only the necessary flow control function, achieving it by adjusting pump output directly rather than restricting flow through valves, thereby eliminating the energy losses associated with valve pressure drops.
Solution Approach 2:
The system changes the operating parameters of the pumps (rotation speed, flow rate, pressure) to match the actual cooling requirements in real-time, avoiding the energy waste of maintaining high pressure and then restricting flow through valves, and delivering coolant at the optimal pressure and flow rate needed.
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 solution allows for rapid adjustment of coolant flow, reducing switching times to under 0.2 seconds, improving accuracy to 0.1%, minimizing energy consumption, and extending pump service life, while reducing maintenance and operational costs.
Implementation Method 1
A cooling system utilizing variable-speed pumps controlled by a frequency converter, eliminating the need for valves and enabling rapid and precise adjustment of coolant flow
Implementation Method 2
a respective pump (10) assigned to each supply line (8), wherein the pump (10) delivers an actual flow (F) of the liquid coolant (7)
Implementation Method 3
the actual flow (F) of the liquid coolant (7) applied to the hot-rolled product (1) by means of the application device (6)
Data Source
AI summary
A cooling section arranged within, upstream of, or downstream of a rolling train is provided. A hot-rolled product made of metal is cooled by the cooling section. Application devices of the cooling section are supplied with an actual current of a water-based liquid coolant via a supply line and a pump. The actual current of the coolant is applied to the hot-rolled product by means of the application device. The hot-rolled product is transported within the cooling section in a horizontal transport direction during the application of the coolant. A controller of the cooling section dynamically ascertains a target actuation state for each pump on the basis of a target current of the coolant to be applied onto the hot-rolled product by the application device and controls the pump in a corresponding manner such that the actual current delivered by each pump approximates the target current as much as possible.