Furnace door nitrogen sealing device of heating furnace and heating furnace

Abstract

A furnace door nitrogen sealing device of a heating furnace and the heating furnace relate to the field of heat treatment. The furnace door nitrogen sealing device of the heating furnace comprises a furnace door refractory material layer connected to the inner wall of one end of the heating furnace, at least one pair of nitrogen spray pipes extending in the width direction of the heating furnace and nitrogen supply pipes connected with the nitrogen spray pipes correspondingly, and each pair of nitrogen spray pipes penetrate through the top and the bottom of the furnace door refractory material layer correspondingly. Each pair of nitrogen spraying pipes is provided with a plurality of nitrogen spraying and sweeping holes communicating with the top wall and the bottom wall in the fire-resistant material layer of the furnace door, the corresponding nitrogen spraying and sweeping holes in the two nitrogen spraying pipes are configured to spray nitrogen so as to form a sealed air curtain when a steel billet enters and exits from the hearth, and a nitrogen supply valve is arranged on the nitrogen supply pipe. According to the heating furnace door nitrogen sealing device and the heating furnace, sealing air curtains can be formed at the top and the bottom of the heating piece of the heating furnace to isolate atmosphere inside and outside the furnace, oxygen outside the furnace is prevented from being sucked into a hearth, and steel billet oxidation burning loss in the furnace is reduced.

Description

Technical Field

[0001] This application relates to the field of heat treatment, and more specifically, to a nitrogen sealing device for a furnace door and a heating furnace. Background Technology

[0002] A heating furnace is a device that heats materials or workpieces (usually metals) to rolling and forging temperatures. Currently, furnace doors are typically made of castings and refractory materials, ensuring rigidity while being able to operate in high-temperature environments for extended periods.

[0003] Utility model patent CN204535410U discloses a heating furnace door, including a door frame and a furnace door body slidably mounted along the vertical direction. The furnace door body is connected to a lifting device that drives its vertical movement. The lifting device includes a winch and a guide wheel mounted on the door frame. A wire rope on the winch passes around the guide wheel and is connected to the furnace door body. The winch is located on one side of the furnace door body, and a balancing mechanism is located on the other side. The balancing mechanism includes a pull rod slidably mounted on the furnace door body, which is fixedly connected to the wire rope. A load seat is fixedly mounted on the door frame, and a spring load rod is slidably mounted on the load seat. A spring is mounted on the spring load rod, which is hinged to the pull rod via a connecting rod. The winch on one side of the furnace door body winds up and unwinds the wire rope, while the balancing mechanism on the other side maintains the smoothness of the furnace door body during lifting and lowering. During lifting, the springs on the two load seats are compressed, and the spring elasticity maintains the balance of the furnace door body.

[0004] The above technical solution has the following defects: due to the entry and exit of materials in the furnace, there will inevitably be a large gap between the furnace door and the materials when the furnace door is opened. The furnace temperature at the discharge end of the heating furnace is usually above 1200℃. Near the negative pressure zone of the flue gas outlet of the heating furnace, the oxygen drawn into the furnace will aggravate the oxidation and burning loss of the steel billet in the furnace. The oxidation and burning loss rate of the steel billet in the heating furnace is usually above 2%. Utility Model Content

[0005] The purpose of this application is to provide a nitrogen sealing device for the furnace door of a heating furnace and a heating furnace, which forms a nitrogen sealing curtain by injecting nitrogen gas into the inner side of the furnace door at the end of the heating furnace to isolate the atmosphere inside and outside the furnace, thereby preventing oxygen from outside the furnace from being drawn into the furnace and reducing the oxidation and burning loss of steel billets inside the furnace.

[0006] This application is implemented as follows:

[0007] This application provides a nitrogen sealing device for a furnace door of a heating furnace, which includes a furnace door refractory material layer connected to the inner wall of one end of the heating furnace, at least one pair of nitrogen nozzles extending along the width direction of the heating furnace, and nitrogen supply pipes respectively connected to each nitrogen nozzle. Each pair of nitrogen nozzles penetrates the top and bottom of the furnace door refractory material layer. Each pair of nitrogen nozzles is provided with multiple nitrogen spray holes that connect the inner top and bottom walls of the furnace door refractory material layer. The corresponding nitrogen spray holes on the two nitrogen nozzles are configured to spray nitrogen to form a sealing air curtain at the top and bottom of the heating element passing through the heating furnace. A nitrogen supply valve is provided on the nitrogen supply pipe.

[0008] In some alternative implementations, an exhaust valve is provided at the end of the nitrogen nozzle away from the nitrogen supply pipe.

[0009] In some alternative implementations, each nitrogen nozzle is provided with a plurality of nitrogen purging holes extending axially, and the nitrogen purging holes are arranged alternately at an angle of 5-10 degrees along the circumference of the nitrogen nozzle, with each end of each nitrogen purging hole extending beyond two adjacent nitrogen purging holes.

[0010] In some alternative implementations, the nitrogen supply line is provided with an intermediate valve and a solenoid valve, with the solenoid valve located between the intermediate valve and the nitrogen supply valve.

[0011] In some alternative embodiments, a bypass pipe is also included, with each end connected to a nitrogen supply pipe. A bypass valve is provided on the bypass pipe, and an intermediate valve, a solenoid valve, and a nitrogen supply valve are located on the nitrogen supply pipe between the two ends of the bypass pipe.

[0012] In some alternative implementations, the nitrogen supply line is equipped with a pressure gauge for detecting its internal pressure.

[0013] In some optional implementations, a photoelectric switch located below the furnace door and a controller electrically connected to the photoelectric switch and the solenoid valve are also included. The photoelectric switch is used to detect the position of the furnace door at one end of the heating furnace when it is raised and lowered to open or close the heating furnace at one end. The controller is used to control the solenoid valve to open or close when the furnace door is raised and lowered to open or close the heating furnace at one end.

[0014] In some optional embodiments, the system also includes a cooling pipe, a cold water supply pipe, and a cold water discharge pipe respectively fitted onto each nitrogen nozzle. The cold water supply pipe and the cold water discharge pipe are respectively connected to each cooling pipe. The cold water supply pipe and the cold water discharge pipe are respectively equipped with a water supply valve and a drain valve. Each nitrogen spray hole of the nitrogen nozzle is respectively connected to a nozzle that penetrates the cooling pipe and the refractory material layer of the furnace door.

[0015] In some alternative implementations, each cooling pipe is equipped with a temperature sensor for detecting the temperature of the cooling water inside it.

[0016] This application also provides a heating furnace, which includes the aforementioned nitrogen sealing device for the furnace door.

[0017] The beneficial effects of this application are as follows: The nitrogen sealing device for the furnace door and the furnace provided in this application control the opening of the nitrogen supply valve when the furnace door is opened, so that nitrogen is introduced into the nitrogen injection pipe through the nitrogen supply pipe, and the nitrogen is injected from multiple nitrogen injection holes into the top and bottom walls of the refractory material layer of the furnace door to form a nitrogen sealing curtain to isolate the atmosphere inside and outside the furnace, prevent oxygen from outside the furnace from being drawn into the furnace chamber, and thus reduce the oxidation and burning loss of the steel billet inside the furnace. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the nitrogen sealing device for the furnace door of the heating furnace provided in Embodiment 1 of this application;

[0020] Figure 2 This is a partial cross-sectional view of the connection between the refractory material layer of the furnace door and the nitrogen nozzle at one end of the furnace door in the nitrogen sealing device of the furnace door provided in Embodiment 1 of this application.

[0021] Figure 3 for Figure 2 A schematic diagram of a partial cross-sectional view at point AA;

[0022] Figure 4 This is a partial structural diagram of the nitrogen nozzle in the nitrogen sealing device for the furnace door of the heating furnace provided in Embodiment 1 of this application;

[0023] Figure 5 For along Figure 4 A schematic diagram of a partial cross-sectional structure at point BB;

[0024] Figure 6 A schematic diagram of the structure of the nitrogen sealing device for the furnace door of the heating furnace provided in Embodiment 2 of this application.

[0025] Figure 7 This is a partial cross-sectional view of the connection between the furnace door, the refractory material layer of the furnace door, and the nitrogen injection pipe at one end of the furnace in the nitrogen sealing device for the furnace door provided in Embodiment 2 of this application.

[0026] Figure 8 This is a partial cross-sectional view of the connection between the refractory material layer of the furnace door and the nitrogen nozzle at one end of the furnace door in the nitrogen sealing device of the furnace door provided in Embodiment 3 of this application.

[0027] Figure 9 This is a partial cross-sectional view of the structure of the nitrogen sealing device for the furnace door of the heating furnace provided in Embodiment 3 of this application, in which the cooling pipe is sleeved on the nitrogen nozzle.

[0028] In the diagram: 100, refractory material layer of furnace door; 101, anchoring nail; 110, nitrogen nozzle; 111, nozzle; 120, nitrogen supply pipe; 130, nitrogen purging hole; 140, nitrogen supply valve; 150, exhaust valve; 160, intermediate valve; 170, solenoid valve; 180, bypass pipe; 190, bypass valve; 200, pressure gauge; 210, controller; 220, photoelectric switch; 230, nitrogen tank outlet valve; 300, cooling pipe; 310, cold water supply pipe; 320, cold water discharge pipe; 330, water supply valve; 340, drain valve; 350, temperature sensor; 400, heating furnace; 410, furnace door. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0035] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0036] The following describes in further detail the nitrogen sealing device for the furnace door of the heating furnace of this application, along with its features and performance, with reference to embodiments.

[0037] Example 1

[0038] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown in the figure, this application provides a nitrogen sealing device for a furnace door of a heating furnace, which includes an annular furnace door refractory material layer 100, a pair of nitrogen nozzles 110 extending along the width direction of the heating furnace, nitrogen supply pipes 120 respectively connected to the two nitrogen nozzles 110, and bypass pipes 180 with both ends connected to the nitrogen supply pipes 120 respectively. The furnace door refractory material layer 100 is connected to the inner wall of the heating furnace 400 near the furnace door 410 by spaced anchoring nails 101. The end of the heating furnace 400 with the furnace door refractory material layer 100 is connected to the furnace door 410, which can be raised and lowered to open and close the heating furnace 400. Each pair of nitrogen nozzles 110 respectively penetrates the top and bottom of the furnace door refractory material layer 100. Two nitrogen nozzles 110 each have five spaced nitrogen purging holes 130 that connect the inner top and bottom walls of the refractory material layer 100 of the furnace door. Each end of the two nitrogen nozzles 110 away from the nitrogen supply pipe 120 is provided with an exhaust valve 150. Each nitrogen purging hole 130 extends along the axial direction of the nitrogen nozzle 110 and is staggered by 10 degrees along the circumference of the nitrogen nozzle 110. Both ends of each nitrogen purging hole 130 extend beyond two adjacent nitrogen purging holes 130. When nitrogen is ejected from the corresponding nitrogen purging holes 130 on the two nitrogen nozzles 110, a sealed air curtain is formed at the top and bottom of the heating element of the heating furnace 400.

[0039] The nitrogen supply pipe 120 is provided with an intermediate valve 160, a solenoid valve 170 and a nitrogen supply valve 140 arranged in sequence, and a bypass valve 190 is provided on the bypass pipe 180. The intermediate valve 160, the solenoid valve 170 and the nitrogen supply valve 140 are located on the nitrogen supply pipe 120 between the two ends of the bypass pipe 180. The nitrogen supply pipe 120 is also provided with a pressure gauge 200 for detecting its internal pressure and a nitrogen tank outlet valve 230.

[0040] The nitrogen sealing device for the furnace door of the heating furnace provided in this embodiment of the application has a nitrogen nozzle 110 extending along the width direction of the heating furnace, which is respectively installed at the top and bottom of the annular furnace door refractory material layer 100 on the inner wall of one end of the heating furnace 400. The two nitrogen nozzles 110 are connected by a nitrogen supply pipe 120. Thus, when the furnace door 410 is raised and the heating furnace 400 is opened, the nitrogen tank outlet valve 230, intermediate valve 160, solenoid valve 170 and nitrogen supply valve 140 are controlled to open, so that nitrogen in the external nitrogen tank is released through the nitrogen supply pipe 120. Two nitrogen nozzles 110 are introduced, allowing nitrogen to be injected through nitrogen spray holes 130 on the nozzles 110 into the top and bottom walls of the refractory material layer 100 inside the furnace door. This forms a sealed air curtain at the top and bottom of the heating elements passing through the heating furnace 400, thereby preventing external air from entering the heating furnace 400 when the furnace door 410 is raised and the heating elements are removed from the furnace, which would cause oxidation and burn-off of the heating elements inside the furnace. This method can reduce the oxidation and burn-off rate of the steel billets in the heating elements of existing heating furnaces to below 1%, which has high economic value.

[0041] Each of the two nitrogen nozzles 110 has an exhaust valve 150 at the end furthest from the nitrogen supply pipe 120. This valve allows nitrogen to be periodically discharged from the furthest end of the nitrogen nozzle 110 by opening the exhaust valve 150, thus using compressed nitrogen to clean the nitrogen nozzle 110 and prevent clogging. Each nitrogen purging hole 130 extends axially along the nitrogen nozzle 110, and the purging holes 130 are arranged alternately at a 10-degree angle along the circumference of the nitrogen nozzle 110. Each nitrogen purging hole 130 extends beyond two adjacent nitrogen purging holes 130, ensuring that the nitrogen flow from each nitrogen purging hole 130 on each nitrogen nozzle 110 is coordinated to form a sealing air curtain at the top and bottom of one end of the heating furnace 400. Thus, the sealing air curtains ejected from each nitrogen purging hole 130 on the two nitrogen nozzles 110 respectively seal the top and bottom of the heating element passing through the heating furnace 400, preventing external air from entering and causing oxidation and burn-out of the heating element.

[0042] The nitrogen supply pipe 120 is equipped with an intermediate valve 160, a solenoid valve 170, and a nitrogen supply valve 140 arranged sequentially. A bypass valve 190 is installed on the bypass pipe 180, with both ends connected to the nitrogen supply pipe 120. The intermediate valve 160, solenoid valve 170, and nitrogen supply valve 140 are located on the nitrogen supply pipe 120 between the two ends of the bypass pipe 180. When the intermediate valve 160, solenoid valve 170, and nitrogen supply valve 140 malfunction and cannot open, the bypass valve 190 is controlled to open, allowing nitrogen to enter the nitrogen supply pipe 120 through the bypass pipe 180 and be delivered to the nitrogen spray holes 130 on the two nitrogen nozzles 110, forming a sealed gas curtain. The nitrogen supply pipe 120 is also equipped with a pressure gauge 200 for detecting its internal pressure, enabling real-time monitoring of the nitrogen delivery within the nitrogen supply pipe 120 and ensuring timely handling of pipe blockages.

[0043] In other alternative embodiments, the number of nitrogen nozzles 110 may be two, three, or more.

[0044] In other alternative embodiments, the angle at which the individual nitrogen spray holes 130 are alternately staggered along the circumference of the nitrogen nozzle 110 can be any angle between 0 and 10 degrees.

[0045] In other alternative embodiments, the number and length of the nitrogen spray holes 130 opened on the nitrogen nozzle 110 can be adjusted according to the width of the heating furnace 400, and the number of nitrogen spray holes 130 can be five or more.

[0046] Example 2

[0047] like Figure 6 and Figure 7As shown, this application also provides a nitrogen sealing device for the furnace door of a heating furnace, which has a structure that is generally the same as the nitrogen sealing device for the furnace door of the heating furnace provided in Embodiment 1. The difference is that in this embodiment, a photoelectric switch 220 is provided below the furnace door 410 and a controller 210 is electrically connected to the photoelectric switch 220 and the solenoid valve 170 respectively. The photoelectric switch 220 is used to detect the position of the furnace door 410 at one end of the heating furnace 400, and the controller 210 is used to control the solenoid valve 170 to connect or disconnect when the furnace door 410 is raised and lowered to open and close the heating furnace 400.

[0048] The nitrogen sealing device for the furnace door of the heating furnace provided in this embodiment detects the position of the furnace door 410 of the heating furnace 400 when it is closed by setting a photoelectric switch 220. The nitrogen tank outlet valve 230, intermediate valve 160 and nitrogen supply valve 140 are pre-connected. When the furnace door 410 is raised and one end of the heating furnace 400 is opened by using a lifting mechanism, the photoelectric switch 220 cannot detect the position of the furnace door 410 and sends a signal to the controller 210. The controller 210 controls the solenoid valve 170 to connect, so that the nitrogen in the nitrogen tank can be transported through the nitrogen supply pipe 120 to the nitrogen spray holes 130 on the two nitrogen spray pipes 110 to form a sealing air curtain. When the furnace door 410 is lowered and one end of the heating furnace 400 is closed by using a lifting mechanism, the photoelectric switch 220 detects the position of the furnace door 410 again and sends a signal to the controller 210. The controller 210 controls the solenoid valve 170 to cut off and stop the supply of nitrogen, thereby saving nitrogen.

[0049] Example 3

[0050] like Figure 8 and Figure 9 As shown, this application embodiment also provides a nitrogen sealing device for the furnace door of a heating furnace, which has a structure that is generally the same as the nitrogen sealing device for the furnace door of the heating furnace provided in Embodiment 1. The difference is that in this embodiment, a cooling pipe 300 is respectively sleeved on two nitrogen nozzles 110. One end of the two cooling pipes 300 is connected to a cold water supply pipe 310, and the other end of the two cooling pipes 300 is connected to a cold water discharge pipe 320. A water supply valve 330 and a drain valve 340 are respectively provided on the cold water supply pipe 310 and the cold water discharge pipe 320. Each cooling pipe 300 is provided with a temperature sensor 350 for detecting the temperature of the cooling water inside it. Each nitrogen spray hole 130 of the nitrogen nozzle 110 is respectively connected to a nozzle 111 that penetrates the cooling pipe 300 and the refractory material layer 100 of the furnace door.

[0051] The nitrogen sealing device for the furnace door provided in this embodiment of the application uses a cooling pipe 300 fitted onto the nitrogen nozzle 110 and cooling water supplied through a cold water supply pipe 310 to the cooling pipe 300. This allows the annular space between the nitrogen nozzle 110 and the corresponding cooling pipe 300 to be filled with cooling water, providing cooling protection for the nitrogen nozzle 110. This prevents nitrogen leakage caused by high temperatures after prolonged use and damage to the furnace door refractory material layer 100, which could affect the formation of the sealing air curtain. This effectively protects and extends the service life of both the furnace door refractory material layer 100 and the nitrogen nozzle 110. Each cooling pipe 300 is equipped with a temperature sensor 350 to detect the temperature of the cooling water inside. The temperature sensor 350 can detect the temperature of the cooling water in the annular space between the nitrogen nozzle 110 and the corresponding cooling pipe 300 in real time, ensuring stable cooling of the furnace door refractory material layer 100 and the nitrogen nozzle 110 by the cooling water in the cooling pipe 300.

[0052] This application also provides a heating furnace, which includes the above-described nitrogen sealing device for the furnace door.

[0053] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A nitrogen sealing device for a furnace door of a heating furnace, characterized in that, It includes a furnace door refractory material layer connected to the inner wall of one end of the heating furnace, at least one pair of nitrogen nozzles extending along the width direction of the heating furnace, and nitrogen supply pipes respectively connected to each of the nitrogen nozzles. Each pair of nitrogen nozzles penetrates the top and bottom of the furnace door refractory material layer. Each pair of nitrogen nozzles has multiple nitrogen spray holes that connect the inner top and bottom walls of the furnace door refractory material layer. The corresponding nitrogen spray holes on the two nitrogen nozzles are configured to spray nitrogen to form a sealed air curtain at the top and bottom of the heating element passing through the heating furnace. A nitrogen supply valve is provided on the nitrogen supply pipe.

2. The nitrogen sealing device for the furnace door of the heating furnace according to claim 1, characterized in that, An exhaust valve is provided at the end of the nitrogen nozzle away from the nitrogen supply pipe.

3. The nitrogen sealing device for the furnace door of the heating furnace according to claim 1, characterized in that, Each of the nitrogen nozzles has multiple nitrogen spray holes extending axially. The nitrogen spray holes are arranged alternately at an angle of 5-10 degrees around the circumference of the nitrogen nozzle. The two ends of each nitrogen spray hole extend beyond two adjacent nitrogen spray holes.

4. The nitrogen sealing device for the furnace door of the heating furnace according to claim 1, characterized in that, The nitrogen supply pipe is equipped with an intermediate valve and a solenoid valve, with the solenoid valve located between the intermediate valve and the nitrogen supply valve.

5. The nitrogen sealing device for the furnace door of the heating furnace according to claim 4, characterized in that, It also includes a bypass pipe with both ends connected to the nitrogen supply pipe, and a bypass valve is provided on the bypass pipe. The intermediate valve, the solenoid valve and the nitrogen supply valve are located on the nitrogen supply pipe between the two ends of the bypass pipe.

6. The nitrogen sealing device for the furnace door of the heating furnace according to claim 4, characterized in that, The nitrogen supply pipe is equipped with a pressure gauge for detecting its internal pressure.

7. The nitrogen sealing device for the furnace door of the heating furnace according to claim 4, characterized in that, It also includes a photoelectric switch located below the furnace door and a controller electrically connected to the photoelectric switch and the solenoid valve respectively. The photoelectric switch is used to detect the position of the furnace door at one end of the heating furnace when it is raised or lowered to open or close one end of the heating furnace. The controller is used to control the solenoid valve to open or close when the furnace door is raised or lowered to open or close one end of the heating furnace.

8. The nitrogen sealing device for the furnace door of the heating furnace according to claim 1, characterized in that, It also includes a cooling pipe, a cold water supply pipe, and a cold water discharge pipe respectively fitted on each of the nitrogen nozzles. The cold water supply pipe and the cold water discharge pipe are respectively connected to each of the cooling pipes. The cold water supply pipe and the cold water discharge pipe are respectively provided with a water supply valve and a drain valve. Each of the nitrogen spray holes of the nitrogen nozzles is respectively connected to a nozzle that penetrates the cooling pipe and the refractory material layer of the furnace door.

9. The nitrogen sealing device for the furnace door of the heating furnace according to claim 8, characterized in that, Each of the cooling pipes is equipped with a temperature sensor for detecting the temperature of the cooling water inside.

10. A heating furnace, characterized in that, It includes a nitrogen sealing device for the furnace door as described in any one of claims 1 to 9.

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