WO2023148771A1

WO2023148771A1 - Apparatus for cooling of hot rolled sheet coils

Info

Publication number: WO2023148771A1
Application number: PCT/IN2023/050104
Authority: WO
Inventors: Gautam WAGLE
Original assignee: Hindalco Industries Limited
Priority date: 2022-02-03
Filing date: 2023-02-03
Publication date: 2023-08-10

Abstract

Provided herein is a hot rolled coil cooling apparatus comprises of: an upender assembly including a L-deck capable of tilting about an axis, comprising a first deck and second deck, having a first side and second side, said upender. The first deck comprises of a gap having a circumference, extending downwardly from first side to second side, for air flow. The cooling platform comprises of a plurality of fluid channels disposed on first side of said first deck, for engaging with coil whose axis is vertical. The cooling pad comprises of thermal pad disposed therein. The apparatus further comprises of a means for generating air disposed on second side of first deck; and an elongate baffle plate disposed on first side of said second deck so as to be parallel with the axis of a coil.

Description

APPARATUS FOR COOLING OF HOT ROLLED SHEET COILS

FIELD OF THE INVENTION

[1] The present invention relates to an apparatus for cooling of hot rolled sheet coils, in particular relates to an apparatus for cooling aluminium sheet coils.

BACKGROUND OF THE INVENTION

[1] In metal-rolling processes, a metal ingot at high temperature is rolled under speed under the pressure, so as to reduce the thickness of metal ingot into thin metal sheets. Due to high metal deformation, there is heat generated which is transferred in the interface of sheet metal and roll. Since the sheet rolling process occur under extremely high pressure, high velocity, and high heat flux, controlling the sheet temperatures possess challenges.

[2] Conventionally the rolled strip cooled by various water jets as well as the ambient air along a runout table. Several other methods of cooling rolled metal strips were reported earlier.

[3] A method for cooling pressed rolling strips are known in EP-A-0343103 which recites that water mist is generated by means of spray nozzles.

[4] EP-A-0695590 describes a method and a device for cooling known from hot-rolled plates and strips made of an aluminum alloy, being cut strips continuously a cooling station run through and directly charged with water via flat jet nozzles become. Immediately after it exits the flat fan nozzle the waterjet periodically by means of air or water jets distracted that the water jet hitting the plate or belt surface performs a wiping motion. With the use of flat jet nozzles arises when the waterjet hits the plate or belt surface a narrow impact surface with high heat transfer.

[5] U.S. Pat. No. 5,701,775 provides a process and apparatus of cooling horizontally- advancing metal strips by applying upward jets of liquid coolant only to the lower surface of the strip and then removing the coolant from the lower surface by directing liquid knives against the lower surface of the strip.

[6] Use of cooling medium such as water can reduce cooling times but can lead to staining. Use of medium such as oil which is used for cold rolled coils between passes can cause fumes and/or fire hazards due to higher temperatures. An alternative coolant is liquid nitrogen (LN2). This cannot be recycled. But, on a large scale it is sufficiently inexpensive. In certain materials or alloys, cooling of rolled strip in between rolling is not advisable due to metallurgical considerations until final rolling is complete and the sheet is coiled up.

[7] In case of aluminium, hot rolled aluminium coils exit the hot rolling mill at temperatures above 300°C. Before subsequent cold rolling of these coils to lower thicknesses in a cold rolling mill, these hot rolled coils need to be cooled to metal temperature less than 50°C.

[8] The effective thermal conductivity in a strip coil is much lower in the radial direction through coil layers than in the axial direction, therefore, the most effective way of heating or cooling of the coil through the side surface of the coils.

[9] Therefore, in industrial practice, such hot rolled aluminium rolls are cooled using forced convection through axial blowers or fans directing the flow to the side wall of the coil for better heat transfer. Forced convective heat transfer typically requires 24 hours to 40 hours of cooling time depending on size of the coils and ambient air temperature. Improved air flow using ducting and channels or cooler air leads to marginal improvement in the rate of convective heat transfer.

SUMMARY OF THE INVENTION

[10] It is therefore an object of the invention to cool rolled aluminium coils by a combination of conduction and forced convection.

[11] An object of the invention is to provide an apparatus for cooling rolled aluminium coils.

[12] For achieving the above object, the invention provides a hot rolled coil cooling apparatus comprises of: an upender assembly including a L-deck capable of tilting about an axis, comprising a first deck and second deck, having a first side and second side, said upender, said first deck comprising of a gap having a circumference, extending downwardly from first side to second side, for air flow, a cooling platform comprises of a plurality of fluid channels disposed on first side of said first deck, for engaging with coil whose axis is vertical, said cooling pad comprises of thermal pad disposed therein, a means for generating air disposed on second side of first deck; and an elongate baffle plate disposed on first side of said second deck so as to be parallel with the axis of a coil.

DESCRIPTION OF THE DRAWINGS

[13] The foregoing summary, as well as the following detailed description of the invention will be better understood when read in conjunction with the appended drawings. For the purpose of assisting in the explanation of the invention, the details are shown in the drawings embodiments which are presently preferred and considered illustrative. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown therein. In the drawings:

[14] Figure 1 is hot rolled coil cooling apparatus of the present application without a hot rolled coil.

[15] Figure 2 is hot rolled coil cooling apparatus of the present application with a hot rolled coil mounted.

[16] Figure 3 is the upender assembly of hot rolled coil cooling apparatus of the present application.

[17] Figure 4 is the cooling platform of hot rolled coil cooling apparatus of the present application.

[18] Figure 5 is the thermal pad of hot rolled coil cooling apparatus of the present application.

[19] Figure 6 is the baffle plate of hot rolled coil cooling apparatus of the present application.

BRIEF DESCRIPTION OF THE INVENTION [20] In describing and claiming the invention, the following terminology will be used in accordance with the definitions set forth below. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. As used herein, each of the following terms has the meaning associated with it in this section. Specific and preferred values listed below for individual process parameters, substituents, and ranges are for illustration only; they do not exclude other defined values or other values falling within the preferred defined ranges.

[21] As used herein, the singular forms fl " "an," and "the" include plural reference unless the context clearly dictates otherwise.

[22] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the ssaammee or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention

[23] As used herein, the terms “comprising” “including,” “having, «” 6 “4,containing,” “involving,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to.

[24] Referring to figure 1, the hot rolled coil cooling apparatus comprises of an upender assembly including a L-deck capable of tilting about an axis. The L-deck comprises of a first deck and second deck, having a first side and second side each. Said first deck comprises of an elongated gap having a circumference, extending downwardly from first side to second side, throughout the thickness of first deck. [25] The apparatus comprises of a means for generating air, disposed on said second side of first deck. In an embodiment, said means for generating air is an axial fan. Said axial fan is disposed in such a way that, the air generated will be directed through said elongated gap in first deck. The apparatus comprises of a thermal pad disposed on first side of said first deck, for engaging with coil whose axis is vertical.

[26] The thermal pad comprises of a cooling platform disposed therein. The cooling platform comprises of a plurality of fluid channels for carrying a fluid, preferably water. An elongated baffle plate disposed on first side of said second deck so as to be parallel with the axis of a coil.

[27] The method of cooling a hot rolled coil using the present apparatus direct conductive heat transfer between the side wall of a hot rolled coil and an internally cooled thermally conductive plate material is utilized to improve heat transfer mechanism for heat extraction from the side wall of the coil. It was observed that, surprisingly, a good thermal contact between two surfaces, that is, coil side wall and the thermal pad, established by compressive forces due to the coil’s self-weight acting on thermal conductive gasket integrated with the apparatus, leads to a significant decrease in cooling time and enhancement in heat flux.

[28] The water channels circulate water inside the thermal pad, thereby preventing direct contact of water with surface of hot rolled coil to avoid staining. The internal circulation of water will ensure that the heat conducted from hot rolled coil is carried away by the water and the apparatus is maintained at a uniform temperature. The internal water channel is designed to have the best heat transfer between the coil side wall. A water inlet and outlet is configured to ensure maximum rate of heat transfer away from the cooling platform. The axial fan is provided to increase the cooling efficiency.

[29] The gap in first deck allows for improved forced convective heat transfer to the hot rolled coil. The surface of the opening is designed to allow the cold platform to reduce the temperature of the air thereby increasing the heat transfer for the same heat transfer coefficient. A baffle plate provided at second deck ensure the air is directed along the opposite face and improve the cooling efficiency through forced convection from the other face.

[30] The apparatus allows for safe loading of hot rolled coils in the eye-to-wall configuration from a typical eye-to-wall configuration exit from the coiler at the end of the hot rolling process in a hot mill using conventional coil handling systems such as overhead crane or forklift. The apparatus is fabricated on the side of upender which then becomes the cooling base once the coil is tilted on the upender. A fixture to fix/remove the baffle plate in upended after loading the coil will allow for the entire design to be integrated as a batch cooler for hot rolled coil.

[31] The apparatus of the present application achieves a cooling effect, which reduces energy consumption and delivers better product quality through higher surface temperature uniformity.

Claims

1 ) A hot rolled coil cooling apparatus comprises of: an upender assembly including a L-deck capable of tilting about an axis, comprising a first deck and second deck, having a first side and second side, said upender, said first deck comprising of a gap having a circumference, extending downwardly from first side to second side, for air flow, a cooling platform comprises of a plurality of fluid channels disposed on first side of said first deck, for engaging with coil whose axis is vertical, said cooling pad comprises of thermal pad disposed therein, a means for generating air disposed on second side of first deck; and an elongate baffle plate disposed on first side of said second deck so as to be parallel with the axis of a coil.

2) The apparatus as claimed in claim 1, wherein said thermal pad is a sheet of thermally conductive material, preferably silicone rubber.

3) The apparatus as claimed in claim 1, wherein said thermal pad comprises of heat conducting material to fill the air gap for enhancing heat transfer.

4) The apparatus as claimed in claim 1, wherein said fluid channels of cooling platform comprises of heat transfer fluids, preferably water or glycol.

5) The apparatus as claimed in claim 4, wherein said cooling platform comprises of a plurality of gap for air flow.

6) The apparatus as claimed in claim 1 , wherein said means for generating air is an axial air blower.