Cooling device and method for cooling elements passing through said device

Abstract

The invention relates to a cooling device (100) for cooling at least one element (150, 151) passing through said device, comprising a metal block (115), having a first side and a second side, and comprising a cooling channel (130) for cyrogenic gas. The at least one element (150, 151) can be guided along the sides of the first side of the metal block (115), the cooling channel (130) is at least partially in heat conductive connection with the second side of the metal block (115), and the cooling channel (130) has an attachment (131) on a first end for the entry of cryogenic gas and an attachment on a second end for the exit of cryogenic gas. The invention also comprises a hardening device having such a cooling device (100) and a method for cooling at least one element (150, 151) passing through said device.

Claims

1. A cooling device (100) for cooling at least one element (150, 151) passing through said cooling device, said cooling device comprising: a metal plate (115) with a first side and a second side and a cooling channel (130) for a cryogenic gas, wherein the first side of the metal plate (115) is adapted to permit at least one element (150, 151) to be guided along the first side of the metal plate (115) in thermally conductive contact with the first side of the metal plate (115), wherein the cooling channel (130) is at least sectionally connected to the metal plate (115) in a thermally conductive manner, and wherein the cooling channel (130) comprises a first connection (131) on a first end thereof for introducing a cryogenic gas, and a second connection (132) on a second end thereof for discharging the cryogenic gas.

2. The cooling device (100) according to claim 1, further comprising a gas line (135), which branches off from the cooling channel (130) at a second end thereof, for conveying cryogenic gas from the cooling channel (130) into a region above the first side of the metal plate (115).

3. The cooling device (100) according to claim 2, wherein the region above the first side of the metal plate (115) comprises an entry region for introducing the at least one element (150, 151) into the cooling device (100) and/or an exit region for withdrawing the at least one element (150, 151) from the cooling device (100).

4. The cooling device (100) according to claim 1, further comprising at least one metal cover plate (120) which is arranged above the metal plate (115) in such a way that a channel for the at least one element (150, 151) is formed between the metal plate (115) and the metal cover plate (120).

5. The cooling device (100) according to claim 1, wherein the cooling channel (130) at least sectionally extends from an exit side of the at least one element (150, 151) to an entry side of the at least one element (150, 151) in a winding manner.

6. The cooling device (100) according to claim 1, wherein the cooling channel (130) comprises a pipeline, or is machined into the metal plate (115), or is machined into an additional metal plate, which is connected to the metal plate (115) in a thermally conductive manner.

7. The cooling device (100) according to claim 1, wherein the at least one element (150, 151) comprises a strip or a wire.

8. The cooling device (100) according to claim 1, wherein the cryogenic gas comprises liquid and/or gaseous nitrogen.

9. The cooling device (100) according to claim 1, further comprising an external housing (160, 161), in which the metal plate (115) and the cooling channel (130) are arranged, wherein the metal plate (115) and the cooling channel (130) are surrounded by an insulation housing (170, 171) of thermally insulating material, and wherein the insulation housing (170, 171) is only connected to the external housing (160, 161) at discrete locations.

10. The cooling device according to claim 9, wherein the external housing (160, 161) and the insulation housing (170, 171) respectively comprise a bottom part (160, 170) and a cover (161, 171), wherein the bottom part of the external housing and the bottom part of the insulation housing are connected to one another, and wherein the cover of the housing and the cover of the insulation housing are connected to one another.

11. A hardening device (200) for at least one element (150) passing through said hardening device, said hardening device comprising: a cooling device (100) according to claim 1 a furnace (201) and a control valve (273), wherein the furnace (201) is arranged upstream of the cooling device (100) referred to the moving direction of the at least one element (150), wherein a gas line (210) for cryogenic gas is provided and makes it possible to convey cryogenic gas being discharged from the cooling channel (130) of the cooling device (100) into the furnace (201), and wherein the control valve (273) is arranged downstream of a discharge point of the cryogenic gas from the cooling channel (130) and can be used for controlling a flow of cryogenic gas through the cooling channel (130) and/or at least one temperature in the cooling device (100).

12. A method for cooling at least one passing element (150) using a cooling device (100) according to claim 1, wherein the at least one element (150, 151) is guided along a first side of the metal plate (115) and is in thermally conductive contact with the first side of the metal plate (115), and wherein the metal plate (115) is cooled by conveying cryogenic gas through a cooling channel (130), which is connected to the metal plate (115) in a thermally conductive manner, in order to indirectly cool the passing element (150).

13. The method according to claim 12, wherein cryogenic gas being discharged from the cooling channel (130) is made available to at least one other application through which the at least one element (150) passes, in order to form an inert gas atmosphere in the furnace (150).

14. The method according to claim 12, wherein a strip is used as the at least one element (150, 151).

15. The method according to claim 12, wherein hydrogen is used as cryogenic gas, and wherein the hydrogen is introduced into the cooling channel (130) in liquid form and discharged from the cooling channel (130) in gaseous form.

16. A method for cooling at least one passing element (150) using a hardening device (100) according to claim 11, wherein the at least one element (150, 151) is guided along a first side of the metal plate (115) and is in thermally conductive contact with the first side of the metal plate (115), and wherein the metal plate (115) is cooled by conveying cryogenic gas through the cooling channel (130), which is connected to the metal plate (115) in a thermally conductive manner, in order to indirectly cool the passing element (150).

17. The cooling device according to claim 1, wherein the cooling channel (130) is at least sectionally connected to the second side of the metal plate (115) in a thermally conductive manner.

18. The cooling device (100) according to claim 1, wherein the at least one element (150, 151) comprises a metal strip.

19. The cooling device (100) according to claim 9, wherein the thermally insulating material is glass-fiber reinforced plastic.

20. The cooling device (100) according to claim 1, wherein passage of the cryogenic gas through the cooling channel provides for indirect cooling of the metal plate (115) by the cryogenic gas flowing through the cooling channel (130).

21. A cooling device (100) for cooling at least one element (150, 151) passing through said cooling device, said cooling device comprising: a housing (101), a metal plate (115) with a first side and a second side and a cooling channel (130) for a cryogenic gas, and a passage within said housing for passing at least one element (150, 151) to be cooled through the housing and along the first side of the metal plate (115) in thermally conductive contact with the first side of the metal plate (115), wherein the cooling channel (130) is at least sectionally connected to the metal plate (115) in a thermally conductive manner, and wherein the cooling channel (130) comprises a first connection (131) on a first end thereof for introducing a cryogenic gas, and a second connection (132) on a second end thereof for discharging the cryogenic gas.

22. The cooling device (100) according to claim 21, wherein said passage is formed as a channel between a metal cover plate (120), arranged above the metal plate (115), and the metal plate (115).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically shows a preferred embodiment of an inventive cooling device.

(2) FIG. 2 schematically shows a detail of the cooling device according to FIG. 1.

(3) FIG. 3 schematically shows another detail of the cooling device according to FIG. 1.

(4) FIG. 4 schematically shows another preferred embodiment of an inventive cooling device.

(5) FIG. 5 schematically shows a preferred embodiment of an inventive hardening device.

EMBODIMENT OF THE INVENTION

(6) FIG. 1 schematically shows a preferred embodiment of an inventive cooling device 100, in this case in the form of a cross-sectional view, wherein this cooling device is also suitable for carrying out an inventive method. The cooling device 100 presently comprises a housing 101, in which a metal plate 115 made, e.g., of brass is arranged. For example, two metal strips 150, 151 can be guided along the metal plate (perpendicular to the plane of projection) on a first, upper side of the metal plate 115.

(7) This figure furthermore shows an intermediate plate 110 that is made, e.g., of copper and connected to a cooling channel 130 in a thermally conductive manner. In this case, the cooling channel is respectively realized in the form of a pipeline or cooling line. The cooling line 130, which is likewise made, e.g., of copper, comprises a connection 131 for introducing liquid nitrogen or other cryogenic gases. The connection for discharging gaseous nitrogen is not visible in this illustration. With respect to a connection of the cooling device or the cooling line to a nitrogen circuit, we otherwise refer to FIG. 5.

(8) The intermediate plate 110 is furthermore connected to the metal plate 115 in a thermally conductive manner. The cooling line 130 is therefore connected to a second side of the metal plate 115, in this case its lower side, in a thermally conductive manner. In this way, the metal plate 115 and therefore the metal strips 150, 151 being guided along said metal plate are cooled via the intermediate plate 110 when liquid nitrogen or other cryogenic gases flow through the cooling line 130 and evaporate in the process. All in all, this cooling process therefore concerns indirect contact cooling with liquid nitrogen or other cryogenic gases.

(9) It should be noted that the cooling channel could also be milled into the intermediate plate 110 or the metal plate 115 and covered instead of providing a cooling line 130.

(10) This figure furthermore shows a metal cover plate 120, which may likewise be made, e.g., of brass and can be arranged above the metal plate 115 in such a way that a channel for the metal strips 150, 151 is formed between the metal plate 115 and the metal cover plate 120. For this purpose, the side of the metal cover plate 120 facing the metal plate 115, in this case its lower side, comprises webs on its lateral ends, by means of which the metal cover plate can be placed onto the metal plate 115.

(11) This figure furthermore shows a gas line 135, e.g., for gaseous nitrogen, wherein said gas line branches off an end of the cooling line 130 on the discharge side and is oriented over a region above the first side of the metal plate 115, i.e. at the strips 150, 151. In this way, the gaseous nitrogen can be at least partially reused after the cooling process, namely for inerting the region above the metal plate 115 or the metal strips 150, 151 in order to prevent icing due to condensation water formed during a cooling process. The gaseous nitrogen does not serve for cooling the metal strips 150, 151. The metal strips are almost completely or at least essentially cooled due to their contact with the cooled metal plate 115.

(12) It should furthermore be noted that insulation material may be provided in the housing 101 of the cooling device 110 in order to insulate the cooled components from the ambient heat and to thereby realize a more efficient cooling process.

(13) FIG. 2 shows the intermediate plate 110 according to FIG. 1 from below (referred to the illustration in FIG. 1). The cooling line 130, which comprises, for example, a few meandering windings, is illustrated in greater detail in this figure. For example, the cooling line may be soldered or welded onto the intermediate plate 110 and/or fixed thereon by means of clamps or the like. This figure also shows the connection 131 for introducing liquid nitrogen or other cryogenic gases into the cooling line 130 and the connection 132 for discharging gaseous nitrogen from the cooling line 130.

(14) This figure furthermore shows the gas line 135, by means of which gaseous nitrogen can be respectively removed from or branched off the cooling line 130 on its discharge side and used for inerting purposes—as already explained above with reference to FIG. 1. It goes without saying that a valve, for example a throttle valve, may also be respectively provided at the branching or in the gas line 135 in this case in order to adjust the desired amount of gas.

(15) FIG. 3 shows the metal plate 115 according to Figure from above (referred to the illustration in FIG. 1). The metal strips 150 and 151 being guided along the metal plate 115 are illustrated in greater detail in this figure. The process flow direction of the metal strips is indicated with an arrow. In this case, the metal plate 115 may have a length, for example, of about 1 m (in the process flow direction).

(16) This figure furthermore shows that the connection 131 for introducing liquid nitrogen or other cryogenic gases is arranged on the exit side of the metal strips and the connection 132 for discharging gaseous nitrogen is arranged on the entry side of the metal strips. In this way, the exit side is cooled more intensely than the entry side such that the passing metal strips are altogether efficiently cooled.

(17) In addition, this figure once again shows the gas line 135, by means of which gaseous nitrogen can be respectively conveyed onto the upper side of the metal plate 115 or onto the metal strips 150, 151 for inerting purposes. It goes without saying that multiple gas outlet openings may also be provided on the gas line 135 and distributed over the length of the metal plate 115 in the process flow direction.

(18) FIG. 4 schematically shows another preferred embodiment of an inventive cooling device 100′. The heat exchanger unit, which in this case comprises the metal plate 110, the intermediate plate 115, the metal cover plate 120 and the cooling channel 130 (in this case without connections), is arranged on a bottom part 170 of an insulation housing by means of supports. A cover 171 of the insulation housing is arranged on the bottom part such that the heat exchanger unit is surrounded by the insulation housing.

(19) The insulation housing may be made, for example, of glass-fiber reinforced plastic (GRP) that acts in a thermally insulating manner. The insulation housing is in turn arranged in an external housing of the cooling device 100′, which comprises a bottom part 160 and a cover 161. In this case, the bottom part 170 of the insulation housing is arranged directly on the bottom part 160 of the external housing whereas the cover 171 of the insulation housing is only connected to the cover 161 of the external housing at individual discrete locations, one of which is as an example identified by the reference symbol 175, such that a gap remains between the covers and losses due to thermal conduction are minimized.

(20) The cover 171 of the insulation housing is opened simultaneously with opening the cover 161, which is connected to the bottom part 160 of the external housing by means of a hinge 180. In the closed state, the external housing is sealed by means of the seals 181 between the bottom part 160 and the cover 161. In addition, the cover 171 and the bottom part 170 of the insulation housing should be adapted to one another in such a way that the heat exchanger unit is surrounded as completely as possible. It goes without saying that openings for the at least one element have to be provided at the entry and the exit.

(21) In this way, the external housing can be manufactured in a particularly cost-effective manner because its insulation is not as important as in instances, in which no insulation housing is used. The external housing particularly may also be welded such that no moisture can penetrate.

(22) FIG. 5 schematically shows a preferred embodiment of an inventive hardening device 200 in the form of a flow chart, wherein this hardening device is also suitable for carrying out an inventive method. The hardening device comprises a furnace 201, through which the metal strip 150 (in contrast to FIGS. 1 and 3, only one metal strip is illustrated in this figure in order to provide a better overview) initially passes along the process flow direction (indicated with an arrow).

(23) Subsequently, the metal strip 150 passes through a quenching device 202, in which the metal strip 150 is shock-cooled, the cooling device 100 and ultimately a tempering device 203. The cooling device 100 is realized in the form of a cooling device of the type described above with reference to FIGS. 1 to 3. In this respect, we also refer to the corresponding explanations. However, the cooling device 100′ according to FIG. 4 could also be used.

(24) This figure furthermore shows a tank 204 for liquid nitrogen, from which liquid nitrogen can be removed and supplied to the cooling device 100 via a shut-off valve and/or throttle valve 250. This can be realized with a suitable line, preferably an insulated line, which can be connected to the connection 131 illustrated in FIGS. 1 to 3 and therefore to the cooling line 130.

(25) Gaseous nitrogen can now exit the cooling device 110 via a heat exchanger 255. The gas line 135, through which part of the gaseous nitrogen can be removed, is indicated outside the cooling device 100 in this figure in order to provide a better overview.

(26) The gaseous nitrogen remaining downstream of the branching can now be heated in the heat exchanger 255. An electric heating device may also be provided alternatively to the heat exchanger.

(27) Subsequently, the gaseous nitrogen is conveyed through a throttle valve 260 and a control valve 273. In this case, a bypass is provided via the shut-off valve and/or throttle valve 263. The control valve 273 presently comprises a motor-driven actuating drive, which in turn may be activated, for example, by means of a computer unit 280.

(28) The computer unit 280 is furthermore designed for detecting a temperature in the cooling device 100, for example by means of a temperature sensor 180 at the exit of the metal strip 150 in the cooling device 100. This temperature can now be controlled in such a way that a flow-through opening of the control valve 273 is used as manipulated variable. In this way, the temperature in the cooling device can be controlled by adapting the flow of gaseous nitrogen from the cooling line, which also affects the flow of liquid nitrogen. It goes without saying that the temperature at the exit of the metal strip can also be controlled in this way.

(29) Desirable temperatures at the exit of the metal strip lie, for example, at about 140 K to 150 K. In this way, the best retained austenite conversion possible can take place in the metal strip on the one hand and excessive icing can be prevented on the other hand.

(30) The gaseous nitrogen can furthermore be supplied to other consumers via the valves 271 and 261 and, in particular, to the furnace 201 via the gas line 210. In this case, a safety valve or pressure control valve 270, which opens, e.g., starting at a pressure of 13.5 bar, may also be provided.

(31) The supply for the additional consumers or the furnace may also be connected to a supply line from the tank 204 via an evaporator 275 and a valve 274. In this way, a potentially incorrect amount of gaseous nitrogen for the additional consumers or the furnace 201 can be replenished from the tank 204.

(32) In order to ensure a reliable gas flow, the valves 261, 274 and 271 may be designed for only releasing the blackflow starting at pressures of 12 bar, 12.5 bar and 13 bar (in this sequence). It goes without saying that different pressure values may also be used in ascending sequence.

(33) The gaseous nitrogen can now be used for forming an inert gas atmosphere in the furnace 201. In this way, the gaseous nitrogen produced during the course of cooling the metal strip can be reused—in addition to its use for inerting purposes. All in all, a very energy-efficient and environmentally compatible method for cooling metal strips is thereby realized.