Liquid nitrogen rapid cooling device for vacuum oxygen-free heating furnace

Abstract

The utility model provides a kind of liquid nitrogen rapid cooling device for vacuum oxygen-free heating furnace, it includes the discharge cooling zone being communicated or cut off with the heating area of vacuum oxygen-free heating furnace by having airtight isolation door, when heating area and discharge cooling zone are communicated, material piece can be transported from heating area to discharge cooling zone;Heating area and discharge cooling zone are respectively correspondingly provided with vacuum system that can make heating area and discharge cooling zone be in vacuum oxygen-free environment;Discharge cooling zone is also provided with liquid nitrogen cooling system, when discharge cooling zone is in vacuum oxygen-free environment state, liquid nitrogen cooling system can cool the material piece transported to discharge cooling zone.The utility model provides a kind of liquid nitrogen rapid cooling device for vacuum oxygen-free heating furnace, can be in the process of discharging material piece fast and evenly cooling while eliminating scale, subsequent will not wear and tear hairiness mould, can greatly improve mould service life;In addition, without again throwing shot to remove scale, can effectively shorten construction period, improve material piece quality.

Description

Technical Field

[0001] This utility model belongs to the field of hot stamping forming technology, and in particular relates to a liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace. Background Technology

[0002] Currently, the application of liquid nitrogen cooling technology in the automotive thermoforming industry still faces significant technological gaps and is largely in the exploratory research stage. Although this technology has unique advantages in rapid cooling and oxidation protection, its industrial application still faces the following key challenges:

[0003] 1. The challenge of matching cooling processes with material properties

[0004] Existing technologies have not yet effectively solved the compatibility problem between liquid nitrogen ultra-rapid cooling (-196℃) and the phase transformation characteristics of high-strength steel materials. Extreme cooling rates may lead to uneven stress distribution inside the material, affecting the mechanical properties and dimensional stability of the final product.

[0005] 2. Insufficient uniformity of spraying and inadequate process controllability

[0006] Current liquid nitrogen spraying systems struggle to ensure uniform cooling when used on large sheet metal components (such as car doors and B-pillars). The lack of intelligent dynamic control methods prevents precise cooling of different areas.

[0007] 3. Bottlenecks in safety protection and process integration

[0008] Maintaining a stable inert gas protective atmosphere in an open production environment to prevent secondary oxidation of high-temperature boards during transportation remains a technical challenge to be solved. Utility Model Content

[0009] In view of the problems existing in the prior art, the main purpose of this utility model is to provide a liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace. The provided liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace can quickly and uniformly cool the material during the discharge process while preventing the generation of oxide scale. It will not wear and scratch the mold in the future, and can greatly improve the service life of the mold. In addition, there is no need to remove oxide scale by shot blasting, which can effectively shorten the construction period and improve the quality of the material.

[0010] The objective of this utility model is achieved through the following technical solution:

[0011] This utility model provides a liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace includes a discharge cooling zone that can be connected to or separated from the heating zone of the vacuum oxygen-free heating furnace through an airtight isolation door. When the heating zone and the discharge cooling zone are connected, the material can be transported from the heating zone to the discharge cooling zone.

[0012] The heating zone and the discharge cooling zone are respectively equipped with vacuum systems that enable the heating zone and the discharge cooling zone to be in a vacuum oxygen-free environment;

[0013] The discharge cooling zone is also equipped with a liquid nitrogen cooling system. When the discharge cooling zone is in a vacuum oxygen-free environment, the liquid nitrogen cooling system can cool the materials transported to the discharge cooling zone.

[0014] As a further description of the above technical solution, the liquid nitrogen cooling system includes an explosion-proof valve located at the top of the discharge cooling zone and a spray assembly for spraying liquid nitrogen onto the material; wherein,

[0015] The explosion-proof valve is opened before the spraying assembly starts spraying operations; the explosion-proof valve is closed after the spraying assembly completes spraying operations.

[0016] As a further description of the above technical solution, the spray assembly includes multiple main pipes for conveying liquid nitrogen and multiple branch pipes connected to the main pipes. Each branch pipe is provided with a liquid nitrogen valve between it and the main pipe, and a nozzle is also provided at one end of the branch pipe that enters the discharge cooling zone.

[0017] As a further description of the above technical solution, at least the outer walls of the main pipe and branch pipes exposed outside the discharge cooling zone are provided with a heat insulation layer.

[0018] As a further description of the above technical solution, the main pipe and the branch pipe are connected by a vacuum flange.

[0019] As a further description of the above technical solution, the multiple main pipes are arranged along the length direction of the discharge cooling zone, and the multiple branch pipes are arranged along the width direction of the discharge cooling zone; or,

[0020] The multiple main pipes are arranged along the width direction of the discharge cooling zone, and the multiple branch pipes are arranged along the length direction of the discharge cooling zone.

[0021] As a further description of the above technical solution, the outlet of the discharge cooling zone has an airtight discharge furnace door, which is in the open state when the liquid nitrogen cooling system cools the material transported to the discharge cooling zone.

[0022] As a further description of the above technical solution, the discharge cooling zone is also equipped with an infrared thermal imager to detect the temperature of the material, and the infrared thermal imager is communicatively connected to the liquid nitrogen cooling system.

[0023] As a further description of the above technical solution, the vacuum degree of the discharge cooling zone is 0.1pa-1000pa.

[0024] As a further description of the above technical solution, the discharge cooling zone is equipped with a vacuum gauge for monitoring the vacuum level, and the vacuum gauge is communicatively connected to the vacuum system.

[0025] Based on the above technical solutions, the outstanding effects of this utility model are as follows:

[0026] The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace provided by this utility model includes a discharge cooling zone that can be connected to or separated from the heating zone of the vacuum oxygen-free heating furnace through an airtight isolation door. After the material is heated in the heating zone of the vacuum oxygen-free heating furnace, the airtight isolation door between the heating zone and the discharge cooling zone is opened to connect the two, so that the material can be transported from the heating zone to the discharge cooling zone for cooling and removal from the furnace. The heating zone and the discharge cooling zone are respectively equipped with vacuum systems that keep the heating zone and the discharge cooling zone in a vacuum oxygen-free environment. This allows the heating zone to heat the material in a vacuum oxygen-free environment, and the discharge cooling zone to maintain a vacuum oxygen-free environment when the material is transported to the discharge cooling zone. This ensures that no oxide scale is generated in the material during heating and subsequent transportation, and that the subsequent wear and tear on the drawing die is prevented, which can significantly improve the service life of the die. In addition, there is no need to remove the oxide scale by shot blasting, and there is no need to consider the deformation or cracking of the material caused by shot blasting. The discharge cooling zone is also equipped with a liquid nitrogen cooling system. When the discharge cooling zone is in a vacuum oxygen-free environment, the liquid nitrogen cooling system can use liquid nitrogen to rapidly cool the parts transported to the discharge cooling zone to the process set temperature, while meeting the automated production cycle. Therefore, using this vacuum oxygen-free heating furnace to produce material racks effectively solves problems such as oxide scale, mold wear, and cumbersome shot blasting processes in traditional hot stamping processes, while improving product quality and production efficiency. Attached Figure Description

[0027] Figure 1 This is an axonometric view of the discharge cooling zone of the liquid nitrogen rapid cooling device for the vacuum oxygen-free heating furnace in this embodiment of the present invention;

[0028] Figure 2 This is a cross-sectional view of the discharge cooling zone of the liquid nitrogen rapid cooling device for the vacuum oxygen-free heating furnace in this embodiment of the present invention.

[0029] Figure 3 This is a front view of the discharge cooling zone of the liquid nitrogen rapid cooling device for the vacuum oxygen-free heating furnace in this embodiment of the present invention;

[0030] Figure 4 This is a top view of the discharge cooling zone of the liquid nitrogen rapid cooling device for the vacuum oxygen-free heating furnace in this embodiment of the present invention;

[0031] Figure 5 This is an isometric view of a spray assembly for one branch in an embodiment of this utility model.

[0032] Explanation of icon numbers:

[0033] 1. Material; 2. Isolation door; 3. Discharge cooling zone; 4. Explosion-proof valve; 5. Main pipe; 6. Branch pipe; 7. Liquid nitrogen valve; 8. Nozzle; 9. Discharge furnace door; 10. Ceramic roller assembly. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0035] In the description of this utility model, it should be noted that the terms "upper," "middle," "lower," "inner," "outer," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The implementation methods of this utility model will now be described based on its overall structure.

[0036] Please see Figures 1 to 5 This utility model discloses a liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace includes a discharge cooling zone 3 that can be connected to or separated from the heating zone of the vacuum oxygen-free heating furnace through an airtight isolation door 2. When the heating zone and the discharge cooling zone 3 are connected, the material 1 can be transported from the heating zone to the discharge cooling zone 3.

[0037] The heating zone and the discharge cooling zone 3 are respectively equipped with a vacuum system that enables the heating zone and the discharge cooling zone 3 to be in a vacuum oxygen-free environment;

[0038] The discharge cooling zone 3 is also equipped with a liquid nitrogen cooling system. When the discharge cooling zone 3 is in a vacuum oxygen-free environment, the liquid nitrogen cooling system can cool the material 1 that is transported to the discharge cooling zone 3.

[0039] In the above-described configuration, the liquid nitrogen rapid cooling device for the vacuum oxygen-free heating furnace includes a discharge cooling zone 3 that can be connected to or separated from the heating zone of the vacuum oxygen-free heating furnace through an airtight isolation door 2. After the material 1 is heated in the heating zone, the airtight isolation door 2 located between the heating zone and the discharge cooling zone 3 will open to connect the two, so that the material 1 can be transported from the heating zone to the discharge cooling zone 3 for unloading. The heating zone and the discharge cooling zone 3 are respectively equipped with vacuum systems that enable the heating zone and the discharge cooling zone 3 to be in a vacuum oxygen-free environment. This allows the heating zone to heat the material 1 in a vacuum oxygen-free environment, and when the material 1 is transported to the discharge cooling zone 3, the discharge cooling zone 3 is also kept in a vacuum oxygen-free environment. This ensures that the material 1 will not generate oxide scale during heating and subsequent transportation, and will not wear down the drawing die, thus significantly improving the die's service life. In addition, there is no need to remove the oxide scale by shot blasting, and there is no need to consider the deformation or cracking of the material 1 caused by shot blasting. The discharge cooling zone 3 is also equipped with a liquid nitrogen cooling system. When the discharge cooling zone 3 is in a vacuum oxygen-free environment, the liquid nitrogen cooling system can use liquid nitrogen to rapidly cool the material 1 transported to the discharge cooling zone 3 to the process set temperature, while meeting the automated production cycle. Therefore, using this vacuum oxygen-free heating furnace 2 to produce material racks effectively solves problems such as oxide scale, mold wear, and cumbersome shot blasting processes in traditional hot stamping processes, while improving product quality and production efficiency.

[0040] Please see Figures 1 to 5 Specifically, in this embodiment, the liquid nitrogen cooling system includes an explosion-proof valve 4 located at the top of the discharge cooling zone 3 and a spray assembly for spraying liquid nitrogen onto the material 1. The explosion-proof valve 4 is opened before the spray assembly begins spraying and closed after the spray assembly completes spraying, thereby achieving rapid cooling of the material 1 by utilizing the latent heat of phase change of liquid nitrogen vaporization. The reason for setting the explosion-proof valve 4 and limiting its opening and closing points is that the material 1 transported from the heating zone to the discharge cooling zone 3 is at a very high temperature. When the sprayed liquid nitrogen comes into contact with it, it absorbs a large amount of heat and expands rapidly (approximately 700 times), causing the air pressure in the discharge cooling zone 3 to rise rapidly in a short time, posing a significant safety hazard.

[0041] Specifically, in this embodiment, the spray assembly includes 10 main pipes 5 and 40 branch pipes 6 connected to the main pipes 5 (each group of 4 branch pipes 6 is connected to one main pipe 5). Each branch pipe 6 is equipped with a liquid nitrogen valve 7 between it and the corresponding main pipe 5. A nozzle 8 is also provided at the end of each branch pipe 6 that enters the discharge cooling zone 3. When the liquid nitrogen valve 7 between the branch pipe 6 and the main pipe 5 is opened, liquid nitrogen flows from the main pipe 5 into the branch pipe 6, and finally sprays onto the material 1 transported to the discharge cooling zone 3 from the nozzle 8 at the end of the branch pipe 6 that enters the discharge cooling zone 3. It should be understood that each liquid nitrogen valve 7 can be selected to open or close depending on the size of the material 1, the local temperature, and the flow rate of liquid nitrogen after opening, thereby ensuring that the material 1 can be uniformly cooled. The liquid nitrogen valve 7 can be, for example, a manual vacuum ball valve. Of course, in other embodiments, the number of main pipes 5 and branch pipes 6 can be set to other quantities according to actual production needs, and the distance between the nozzle 8 and the material 1 can also be set according to the spray test results, so as to ensure that the spray surface of liquid nitrogen can uniformly cover the material 1 to be sprayed and achieve the purpose of rapid cooling. According to uncertainty testing, the liquid nitrogen cooling system in this embodiment can cool the material 1 to 580±20℃ within 1-3s, thereby ensuring the temperature uniformity of the material sheet and meeting the cycle time of automated production.

[0042] Specifically, in this embodiment, the discharge cooling zone 3 is equipped with an infrared thermal imager (not shown in the figure) to achieve multi-point detection of the temperature of the material 1. The infrared thermal imager is communicatively connected to the liquid nitrogen cooling system to upload the detected data, thereby allowing the setting of the opening and closing of the liquid nitrogen valve 7 and the degree of opening. It should be understood that when producing the same type of material 1, since the thickness, shape, size, and other parameters of the preceding material 1 are set consistently, the heating parameters set in the heating zone are also consistent. Therefore, the temperature parameters detected by the thermal infrared imager multiple times will tend to stabilize, which also facilitates the setting of whether each liquid nitrogen valve 7 is open and the degree of opening based on this.

[0043] Specifically, in this embodiment, at least the outer walls of the main pipe 5 and branch pipe 6 exposed outside the discharge cooling zone 3 are provided with an insulation layer (not shown in the figure). The purpose of providing the insulation layer is as follows: First, without the insulation layer, the outer wall of the liquid nitrogen will be rapidly cooled as it flows through the main pipe 5 and branch pipe 6 before reaching the nozzle 8, and the liquid nitrogen inside the pipe will also vaporize due to heat absorption, so that the final product sprayed from the nozzle 8 is low-temperature nitrogen gas, not liquid nitrogen; Second, if the outer walls of the main pipe 5 and branch pipe 6 are exposed outside the discharge cooling zone 3, direct contact with the air will generate a large amount of condensate, affecting the operation of the equipment; Finally, the outer walls of the main pipe 5 and branch pipe 6 are rapidly cooled, and the liquid nitrogen valve 7 is located between the main pipe 5 and branch pipe 6 and outside the discharge cooling zone 3 to enable real-time opening and closing and flow regulation. If the liquid nitrogen valve 7 is operated manually, there is a safety hazard of operators accidentally touching the pipe and causing it to freeze.

[0044] Specifically, in this embodiment, the main pipe 5 and the branch pipe 6 are connected by a vacuum flange (not shown in the figure).

[0045] Specifically, in this embodiment, 10 main pipes 5 are arranged along the length of the discharge cooling zone 3, and 40 branch pipes 6 are arranged in 10 groups along the width of the discharge cooling zone 3. This ensures that the spray area of ​​all nozzles 8 at the end of each branch pipe 6 that penetrates the discharge cooling zone 3 is equal to the area of ​​the material 1 delivered to the discharge cooling zone 3, thus achieving a uniform cooling effect on the material 1. Of course, in other embodiments, the multiple main pipes 5 can also be arranged along the width of the discharge cooling zone 3, and the multiple branch pipes 6 can be arranged along the length of the discharge cooling zone 3.

[0046] Specifically, in this embodiment, the outlet of the discharge cooling zone 3 has an airtight discharge furnace door 9. When the liquid nitrogen cooling system cools the material 1 delivered to the discharge cooling zone 3, the discharge furnace door 9 is in the open state, so the discharge furnace door 9 will not obstruct the material 1 from continuing to be discharged. During this process, the liquid nitrogen rapidly vaporizes and expands upon contact with the material 1, which also prevents external air from entering the discharge cooling zone 3 through the discharge furnace door 9 to a certain extent. Furthermore, the liquid nitrogen vaporizes into nitrogen gas, which, as an inert gas, also protects the surface of the material 1. Therefore, the opening of the discharge furnace door 9 will not cause the material 1 to generate oxide scale during the cooling process. In addition, in this embodiment, the vacuum degree of the discharge cooling zone 3 is 0.1 Pa-1000 Pa, so cooling the material 1 with liquid nitrogen is equivalent to being carried out in a vacuum oxygen-free environment. Maintaining a vacuum oxygen-free environment allows the internal stress of the material 1 to be evenly distributed even under extreme cooling rates.

[0047] Specifically, in this embodiment, in order to accurately monitor the vacuum level of the discharge cooling zone 3, the discharge cooling zone 3 is also equipped with a vacuum gauge (not shown in the figure) for monitoring the vacuum level, and the vacuum gauge can be connected to the vacuum system in communication to realize the automatic and stable maintenance of the vacuum level of the discharge cooling zone 3.

[0048] Specifically, in this embodiment, a ceramic roller assembly 10 can be used to convey the material 1.

[0049] Specifically, in this embodiment, the process of rapidly cooling the material 1 after heating is as follows:

[0050] First, after the material 1 is heated in the heating zone of the vacuum oxygen-free heating furnace, nitrogen is purged into the heating zone and the discharge cooling zone 3 to make the pressure difference between them similar. Then, the airtight isolation door 2 between the heating zone and the discharge cooling zone 3 is opened to connect the heating zone and the discharge cooling zone 3, and the explosion-proof valve 4 is opened. Then, the ceramic roller group 10 is started to transport the material 1 from the heating zone to the discharge cooling zone 3. During the transportation process, the discharge furnace door 9 is raised and opened, and the liquid nitrogen valve 7 between the main pipe 5 and the branch pipe 6 is opened (the opening of the liquid nitrogen valve 7 is synchronized with the opening of the discharge furnace door 9), so that liquid nitrogen is sprayed from the nozzle 8 to spray onto the material 1 in the transportation state, so that it can be rapidly cooled to the process temperature (cooling the material 1 to 580±20℃ within 1-3 seconds). After the material 1 is transported to the centering platform outside the discharge furnace door 9, it will be further processed. At this point, material 1 has been completely discharged from the vacuum heating furnace. The liquid nitrogen valve 7 can then be closed to end the spraying operation. Next, the isolation door 2 is lowered and closed to isolate the heating zone and the discharge cooling zone 3. Then, the discharge furnace door 9 is lowered and closed to isolate the discharge cooling zone 3 from the outside of the heating furnace. The explosion-proof valve 4 is then closed, allowing the heating zone and discharge cooling zone 3 to be equipped with vacuum systems to evacuate them, creating a vacuum-free, oxygen-free environment for the next cycle.

[0051] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any changes, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace, characterized in that, It includes a discharge cooling zone that can be connected to or separated from the heating zone of a vacuum oxygen-free heating furnace through an airtight isolation door. When the heating zone and the discharge cooling zone are connected, the material can be transported from the heating zone to the discharge cooling zone. The heating zone and the discharge cooling zone are respectively equipped with vacuum systems that enable the heating zone and the discharge cooling zone to be in a vacuum oxygen-free environment; The discharge cooling zone is also equipped with a liquid nitrogen cooling system. When the discharge cooling zone is in a vacuum oxygen-free environment, the liquid nitrogen cooling system can cool the materials transported to the discharge cooling zone.

2. The liquid nitrogen quenching device for a vacuum oxygen-free heating furnace according to claim 1, characterized by The liquid nitrogen cooling system includes an explosion-proof valve located at the top of the discharge cooling zone and a spray assembly for spraying liquid nitrogen onto the material; wherein... The explosion-proof valve is opened before the spraying assembly starts spraying operations; the explosion-proof valve is closed after the spraying assembly completes spraying operations.

3. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace according to claim 2, characterized in that, The spray assembly includes multiple main pipes for conveying liquid nitrogen and multiple branch pipes connected to the main pipes. Each branch pipe is provided with a liquid nitrogen valve between it and the main pipe, and a nozzle is provided at one end of each branch pipe that enters the discharge cooling zone.

4. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace according to claim 3, characterized in that, At least the main pipes and branch pipes exposed outside the discharge cooling zone have an insulation layer on their outer walls.

5. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace according to claim 3, characterized in that, The main pipe and branch pipes are connected by a vacuum flange.

6. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace according to claim 3, characterized in that, The multiple main pipes are arranged along the length of the discharge cooling zone, and the multiple branch pipes are arranged along the width of the discharge cooling zone; or, The multiple main pipes are arranged along the width direction of the discharge cooling zone, and the multiple branch pipes are arranged along the length direction of the discharge cooling zone.

7. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace according to claim 2, characterized in that, The outlet of the discharge cooling zone has an airtight discharge furnace door. When the liquid nitrogen cooling system cools the material delivered to the discharge cooling zone, the discharge furnace door is in the open state.

8. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace according to claim 1, characterized in that, The discharge cooling zone is also equipped with an infrared thermal imager to detect the temperature of the material, and the infrared thermal imager is communicatively connected to the liquid nitrogen cooling system.

9. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace according to claim 1, characterized in that, The vacuum degree of the discharge cooling zone is 0.1 Pa to 1000 Pa.

10. The liquid nitrogen rapid cooling device for a vacuum oxygen-free heating furnace according to claim 1, characterized in that, The discharge cooling zone is equipped with a vacuum gauge for monitoring the vacuum level, and the vacuum gauge is communicatively connected to the vacuum system.

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