Device for cooling strip-shaped workpieces
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Solution Overview
Problem
Existing cooling devices for strip-shaped workpieces face issues such as oxide layer formation with water-based cooling, high cooling medium consumption with gas-based cooling, and pressure fluctuations due to evaporation, leading to inefficient heat transfer and increased gas usage.
Innovation Solution
A cooling device with a subcooling mechanism using a heat exchanger surface in the supply line, where cold-liquefied gas is subcooled before entering the cooling channel, reducing evaporation and pressure fluctuations, and a nozzle arrangement to inert the cooling surface, ensuring uniform heat transfer and precise gas metering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water or water/oil emulsion is used to cool strip-shaped workpieces, then cooling efficiency is improved, but oxide layers and scale form on the workpiece surface requiring laborious cleaning
Solution Approach 1:
The patent uses nitrogen gas to create an inert atmosphere during the cooling process. The workpiece is cooled while surrounded by nitrogen, which prevents oxidation and scale formation on the workpiece surface, eliminating the need for subsequent cleaning operations.
Solution Approach 2:
The patent introduces nitrogen gas as an intermediary medium between the workpiece and the cooling environment. This intermediary prevents direct contact between the workpiece surface and oxygen, thereby preventing oxide layer formation while still allowing efficient heat transfer.
2Object-generated harmful factors
If cold-liquefied gas is sprayed to cool strip-shaped workpieces, then oxide layer formation is prevented, but cooling medium consumption increases
Solution Approach 1:
The patent implements continuous cooling by guiding the workpiece through a cooling chamber where cold-liquefied nitrogen is continuously supplied. This continuous process ensures consistent cooling and inert atmosphere protection throughout the workpiece, eliminating the need for repeated spraying cycles and reducing overall gas consumption.
Solution Approach 2:
The cooling system is designed to utilize the workpiece's own movement through the cooling chamber as the driving mechanism. The workpiece passes through the cooling zone where nitrogen is supplied, and the continuous flow of workpieces through the system maintains the inert atmosphere and cooling process without requiring additional active control or high gas consumption.
3Power
If cold-liquefied gas evaporates completely in the cooling channel, then cooling capacity is increased, but pressure fluctuations occur leading to heat transfer instability
Solution Approach 1:
The patent carefully controls the parameters of the cold-liquefied nitrogen, specifically its temperature and pressure, before it enters the cooling channel. By adjusting these parameters, the system achieves optimal evaporation rate that provides sufficient cooling capacity while maintaining stable pressure conditions, preventing heat transfer fluctuations.
Solution Approach 2:
The system incorporates pressure monitoring and control mechanisms that detect pressure changes in the cooling channel and adjust the supply of cold-liquefied nitrogen accordingly. This feedback control ensures that evaporation occurs at a rate that maintains stable pressure and consistent heat transfer throughout the cooling process.
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
The solution provides efficient and uniform heat transfer with reduced cooling medium consumption and minimal pressure fluctuations, allowing for precise cooling and inerting of strip-shaped workpieces without laborious cleaning or high gas usage.
Implementation Method 1
a cooling element made of a thermally highly conductive material, which cooling element has a cooling surface along which a strip-shaped workpiece can be guided and brought into thermal contact with this
Implementation Method 2
which evaporates in the container upon thermal contact with the cold-liquefied gas fed through the heat exchanger surface
Implementation Method 3
the evaporation of the cooling medium in the cooling channel can lead to strong pressure fluctuations and thus also to fluctuations in the heat transfer
Data Source
Figure 1
AI summary
A device for cooling strip-shaped workpieces is equipped with a cooling element made of a thermally conductive material. The workpiece to be cooled is continuously guided along this element. Cooling is achieved via a cooling channel thermally connected to the cooling element, through which a cryogenic cooling medium flows. To ensure uniform heat transfer, the cooling medium is supercooled before being fed into the cooling channel. This supercooling is accomplished by thermal contact with a partial flow of the same cooling medium, but at a lower pressure. This subcooled medium evaporates upon thermal contact with the cooling medium flowing into the cooling channel. The evaporated cooling medium is then used to inert the cooling element.