Roller hearth furnace

Abstract

The present invention relates to a roller hearth furnace, comprising a furnace body and a gas inlet assembly arranged at the inner bottom of the furnace body. The gas inlet assembly comprises gas channels in at least two layers arranged in the height direction of the furnace body, and is used for preheating a gas introduced into the furnace body via the gas channels; the gas channel in each layer comprises at least two gas channel pathways, the gas channel pathways being arranged to snake in the plane of the corresponding layer; the gas channel pathways of the gas channels in adjacent layers correspond to each other on an one-to-one basis; each gas channel pathway comprise a gas inlet and a gas outlet, the gas outlet of a gas channel pathway located at a lower layer leading to the gas inlet of the corresponding gas channel pathway located at an upper layer thereof. When the gas is introduced into the bottom of the roller hearth furnace of the present invention, the gas is preheated by means of the gas channels in the gas inlet assembly and then enters the furnace, so that the temperature difference between the temperature of the gas and the temperature in a hearth can be reduced as much as possible, effectively ensuing the uniformity of the temperature in the hearth and thus ensuring the sintering quality.

Description

Roller furnace

[0001] This invention claims priority to Chinese Patent Application No. 2024114951881, filed with the Chinese Patent Office on October 24, 2024, entitled "Roller Furnace", the entire contents of which are incorporated herein by reference.

[0002] This invention claims priority to Chinese Patent Application No. 2024225796527, filed with the Chinese Patent Office on October 24, 2024, entitled "Roller Furnace", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of roller furnace technology, specifically to a roller furnace. Background Technology

[0004] A roller furnace is an industrial heating device widely used in industries such as new energy, lithium batteries, and building materials. Its basic structure typically includes a feeding system, roller conveyor, heating zone, cooling zone, discharging system, and control system. The roller conveyor consists of multiple rollers that support and transport workpieces. Heat is supplied inside the furnace via burners or electric heating elements, ensuring the workpieces reach the required temperature during movement to achieve sintering and other process requirements.

[0005] Lithium iron phosphate (LFP) is a commonly used raw material for lithium batteries and requires sintering in a roller furnace. During sintering, LFP is typically placed in a sagger for sintering. Sintering is one of the core processes in lithium battery manufacturing, and the uniformity of temperature within the furnace is a key factor in the sintering result. Poor temperature uniformity and large temperature fluctuations lead to significant batch-to-batch variations in the sintered LFP, resulting in unstable material structure and performance. Therefore, controlling the stability and uniformity of the furnace temperature during sintering is crucial. To improve the sintering efficiency of LFP, multiple rows and layers of saggers may be placed simultaneously within the furnace, which places even higher demands on the uniformity of the furnace temperature.

[0006] In existing technologies, roller furnaces use bottom air intake, either through air intake pipes or by directly blowing air into the furnace through pre-existing air ducts in the bottom bricks. This method results in cold air, which enters the furnace directly from the bottom, causing the atmosphere in the lower half of the furnace to be colder than that in the upper half. This is especially problematic when the furnace needs to accommodate multiple rows and layers of crucibles, requiring strict control of temperature uniformity.

[0007] Therefore, it is necessary to provide a roller furnace to address the aforementioned technical problems. Summary of the Invention

[0008] The purpose of this invention is to provide a roller furnace that can solve the problem mentioned above where low-temperature cold air enters the furnace directly from the bottom of the furnace body, resulting in inconsistent temperatures in the saggers at different locations and affecting the sintering quality of the materials.

[0009] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0010] A roller furnace includes a furnace body and an air inlet assembly disposed at the bottom of the furnace body. The air inlet assembly includes at least two layers of air passages disposed along the height direction of the furnace body. The air inlet assembly is used to preheat gas introduced into the furnace body through the air passages.

[0011] Each layer of the airway includes at least two airway passages, which are arranged in a spiral pattern in the plane of the corresponding layer. The airway passages of adjacent layers correspond one-to-one. Each airway passage includes an air inlet and an air outlet. The air outlet of the airway passage located in the lower layer is connected to the air inlet of the corresponding airway passage located in the upper layer.

[0012] In one or more embodiments of the present invention, at least one of the airway passages includes a plurality of alternating straight sections and bends, two straight sections connected to the same bend are perpendicular to each other, and non-common straight sections of two adjacent bends are parallel to each other.

[0013] The airway passage includes a first radial section and a second radial section that are adjacent to each other. The gas flow direction is the same in the two radial sections adjacent to the first radial section and the gas flow direction is opposite in the two radial sections adjacent to the second radial section.

[0014] In one or more embodiments of the present invention, at least one of the airway passages includes a plurality of alternating straight segments and bends, two straight segments connected to the same bend are perpendicular to each other, and two non-common straight segments of two adjacent bends are parallel to each other.

[0015] Among them, the gas flow directions are opposite in two adjacent radial sections.

[0016] In one or more embodiments of the present invention, the airway passage has a concave corner and a convex corner at the coiling point, and the concave corner and / or convex corner is chamfered;

[0017] And / or, the air outlets of the uppermost air passage are distributed on the target central axis of the furnace body;

[0018] And / or, the air outlets and inlets of the air passages not located at the topmost level are all distributed on the side of the furnace body;

[0019] And / or, the air intake assembly is constructed of brickwork, with ceramic plates laid on the side of the brickwork facing the air passage.

[0020] In one or more embodiments of the present invention, the top of the furnace body is provided with a plurality of independent exhaust chimneys, the exhaust chimneys including a first exhaust pipe communicating with the furnace body, a second exhaust pipe not collinear with the axis of the first exhaust pipe, and a third exhaust pipe communicating with the first exhaust pipe and the second exhaust pipe, the second exhaust pipe being provided with a gate valve.

[0021] In one or more embodiments of the present invention, an inspection port is provided at the end of the third exhaust pipe away from the first exhaust pipe, and the third exhaust pipe has an inclined angle that allows dust to flow toward the inspection port.

[0022] In one or more embodiments of the present invention, the roller furnace further includes a side heating element whose temperature can be independently controlled, and the side wall of the furnace body is provided with a mounting groove, wherein the side heating element is detachably installed in the mounting groove.

[0023] In one or more embodiments of the present invention, a plurality of side heating elements are provided, and the installation position of the side heating elements is consistent with the height position of the bottom of each odd-numbered layer of saggers located in the furnace body.

[0024] In one or more embodiments of the present invention, a glass plate is fixed to the side of the mounting groove near the interior of the furnace body to isolate the side heating element from the dust inside the furnace body;

[0025] And / or, a support structure is provided above or below the mounting groove on the side wall of the furnace body.

[0026] In one or more embodiments of the present invention, the furnace body is provided with a support mechanism for supporting at least two layers of saggers;

[0027] And / or, the furnace body is provided with a support mechanism for supporting at least two rows of saggers.

[0028] Compared with existing technologies, in this invention, when the roller furnace is fed from the bottom, the gas is preheated through the gas channels within the gas inlet assembly before entering the furnace. This minimizes the temperature difference between the gas and the furnace interior, effectively ensuring temperature uniformity within the furnace and thus guaranteeing sintering quality. Furthermore, the number of gas channel layers and the coiled arrangement of each channel passage extend the gas's residence time within the channels, ensuring thorough preheating and maintaining temperature uniformity within the furnace. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 is a front view of a roller furnace in one embodiment of the present invention;

[0031] Figure 2 is a side view of a roller furnace according to an embodiment of the present invention;

[0032] Figure 3 is a schematic diagram of the structure of the bottom air passage in the air intake assembly according to an embodiment of the present invention;

[0033] Figure 4 is a schematic diagram of the structure of the top air passage inside the air intake assembly in one embodiment of the present invention;

[0034] Figure 5 is an enlarged view of point A in Figure 1;

[0035] Figure 6 is an enlarged view of point B in Figure 2;

[0036] Figure 7 is a schematic diagram of the structure of the side heating element in one embodiment of the present invention.

[0037] Explanation of key figure labels:

[0038] 1. Furnace body; 11. Mounting slot; 2. Upper heating element; 3. Lower heating element; 4. Supporting mechanism; 5. Air intake assembly; 51. Air passage; 511. Straight section; 512. Bend section; 6. Exhaust chimney; 61. First exhaust pipe; 62. Second exhaust pipe; 63. Third exhaust pipe; 64. Gate valve; 65. Inspection port; 7. Side heating element; 8. Glass plate; 9. Support structure. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0040] Referring to Figures 1 and 2, a roller furnace in one embodiment of the present invention includes a furnace body 1, an upper heating element 2 and a lower heating element 3 installed within the furnace body 1, and a support mechanism 4 disposed between the upper heating element 2 and the lower heating element 3. The support mechanism 4 includes multiple conveying rollers for conveying saggers containing lithium iron phosphate. The support mechanism 4 allows the saggers to pass through different temperature zones within the furnace body 1 to complete the sintering of lithium iron phosphate.

[0041] To improve the sintering efficiency of lithium iron phosphate, a support mechanism 4 for supporting at least two layers of saggers is provided inside the furnace body 1; and / or, a support mechanism 4 for supporting at least two rows of saggers is provided inside the furnace body 1. In this embodiment, the support mechanism 4 is provided with multiple rows and multiple layers of saggers, which can sinter multiple lithium iron phosphates simultaneously. The saggers on the support mechanism 4 can be 6 rows and 2 layers, or 6 rows and 3 layers, or 6 layers and multiple rows, etc.

[0042] Referring to Figures 1 and 3, the roller furnace in this embodiment also includes an air intake assembly 5 disposed at the bottom of the furnace body 1. The air intake assembly 5 includes at least two layers of air passages disposed along the height direction of the furnace body 1. The air intake assembly 5 is used to preheat the gas introduced into the furnace body 1 through the air passages. Each layer of air passages includes at least two air passages 51. The air passages 51 are arranged in a coiled manner in the plane of the corresponding layer. The air passages 51 of adjacent layers correspond one-to-one. The air passages 51 include an air inlet and an air outlet. The air outlet of the lower layer of air passage 51 is connected to the air inlet of the corresponding air passage 51 of the upper layer.

[0043] During operation of the roller furnace, the gas entering through the bottom inlet of the furnace body 1 is preheated through the gas passage within the inlet assembly 5 before entering the furnace chamber. Because the gas passage 51 is coiled and has at least two layers along its height, direct gas entry into the furnace chamber is prevented. Furthermore, the number of gas passage layers and the number of gas channels extend the gas's residence time within the passages, ensuring that the temperature of the gas exiting the outlet does not differ significantly from the temperature inside the furnace. This guarantees temperature uniformity within the furnace and thus ensures sintering quality.

[0044] Referring to Figures 3 and 4, this embodiment illustrates the invention by setting up two airway layers, with each airway layer having three airway passages 51. This does not represent a limitation on the number of airway layers and the number of airway passages 51 in the invention.

[0045] Specifically, referring to Figure 3, at least one airway passage 51 includes a plurality of alternating straight sections 511 and bends 512, with two straight sections 511 connected to the same bend 512 being perpendicular to each other, and the non-common straight sections 511 of two adjacent bends 512 being parallel to each other.

[0046] The airway passage 51 includes a first straight section and a second straight section that are adjacent to each other. The gas flow direction in the two straight sections 511 adjacent to the first straight section is the same, and the gas flow direction in the two straight sections 511 adjacent to the second straight section is opposite.

[0047] Referring to FIG4, at least one airway passage 51 includes a plurality of alternating straight sections 511 and bends 512, two straight sections 511 connected to the same bend 512 are perpendicular to each other, and two non-common straight sections 511 of two adjacent bends 512 are parallel to each other; wherein the gas flow direction in two straight sections 511 adjacent to the same straight section 511 is opposite.

[0048] By combining the straight section 511 and the bent section 512, the air passage forms a coiled structure, thus making full use of the internal space of the intake assembly 5. This ensures that the gas travels as far as possible within each air passage 51, thereby guaranteeing the preheating effect of the gas.

[0049] Referring to Figures 3 and 4, the gas passage 51 has concave and convex corners at the coiling point, and the concave and / or convex corners are chamfered. In this embodiment, the coiling point is the connection between the straight section 511 and the bend section 512. By chamfering the concave and / or convex corners, the pressure loss of the gas flow when passing through the bend section 512 of the gas passage can be reduced, thereby ensuring that the gas can enter the furnace with sufficient pressure.

[0050] Referring to Figure 4, the outlets of the uppermost gas passage 51 are distributed along the target central axis of the furnace body 1. By reasonably setting the position of the outlets of the uppermost gas passage 51, the impact of the gas entering the furnace on the original gas inside can be further reduced.

[0051] Referring to Figure 3, the air outlet and air inlet of the non-topmost air passage 51 are both located on the side of the furnace body 1, in order to extend the residence time of the gas in the air passage 51, thereby enhancing the preheating effect of the gas.

[0052] Referring to Figures 3 and 4, in this embodiment, the air intake assembly 5 is constructed of brick, with ceramic plates laid on the side of the brick facing the air passage 51. Because conventional refractory bricks easily pulverize under high temperatures, a large amount of dust will form inside the air passage. This dust, blown into the furnace, will contaminate the furnace atmosphere. Furthermore, the remaining powder deposited inside the air passage may reduce the gas flow rate or even block the passage. Laying ceramic plates around the air passage effectively avoids these phenomena and further reduces friction between the airflow and the air passage, ensuring gas pressure. In other embodiments, the air intake assembly 5 can also be directly configured as a pipe.

[0053] Referring to Figures 1 and 5, the top of the furnace body 1 is provided with multiple independent exhaust chimneys 6. Each exhaust chimney 6 includes a first exhaust pipe 61 connected to the furnace body 1, a second exhaust pipe 62 not collinear with the axis of the first exhaust pipe 61, and a third exhaust pipe 63 connecting the first exhaust pipe 61 and the second exhaust pipe 62. The second exhaust pipe 62 is provided with a gate valve 64.

[0054] Therefore, the third exhaust pipe 63 allows dust mixed in with the gas discharged from the first exhaust pipe 61 to be deposited in the third exhaust pipe 63. At the same time, the positions of the second exhaust pipe 62 and the third exhaust pipe 63 ensure that the gas discharged from the furnace body 1 does not directly impact the slide gate valve 64, thus extending the service life of the slide gate valve 64.

[0055] Referring to Figure 5, a maintenance port 65 is provided at the end of the third exhaust pipe 63 away from the first exhaust pipe 61. The third exhaust pipe 63 has an inclined angle that allows dust to flow towards the maintenance port 65. The maintenance port 65 is provided with a maintenance cover. When the maintenance cover is opened, the dust deposited on the third exhaust pipe 63 flows towards the maintenance port 65, thereby reducing the difficulty of cleaning the deposited dust.

[0056] Referring to Figure 5, in an optional embodiment, an inspection port 65 can also be provided at the end of the first exhaust pipe 61 away from the furnace body 1. In special circumstances, this inspection port 65 can be opened for cleaning and maintenance. Therefore, the structural design of the exhaust chimney 6 of the roller furnace of the present invention makes exhaust more flexible and dust cleaning more convenient, thus enabling it to cope with more complex situations.

[0057] Referring to Figures 6 and 7, the roller furnace of this embodiment also includes a side heating element 7 with independently controllable temperature. The side wall of the furnace body 1 is provided with a mounting groove 11, and the side heating element 7 is detachably installed in the mounting groove 11. Specifically, in this embodiment, the side wall of the furnace body 1 is made of bricks, one of which can have a mounting groove 11 cut into it, and the heating end of the side heating element 7 is located in the mounting groove 11.

[0058] Because the roller furnace has multiple rows and layers of saggers, the space inside the furnace body 1 is also relatively large. Relying on a single upper heating element 2 and lower heating element 3 may result in a large temperature difference in the materials in the same batch of saggers, which may easily lead to a decrease in the yield of sintered materials.

[0059] Therefore, the coordinated arrangement of the side heating element 7, the upper heating element 2, and the lower heating element 3 ensures the uniformity of temperature within the furnace body 1 and improves the adaptability to heating in multi-row, multi-layer roller furnaces. The side heating element 7 is individually controlled and can be adjusted according to the actual temperature, thus preventing excessively high local temperatures on the sides of the furnace body 1.

[0060] Referring to Figure 6, multiple side heating elements 7 are provided, and the installation position of the side heating elements 7 is consistent with the height position of the bottom of each odd-numbered layer of saggers inside the furnace body 1. The position of the side heating elements 7 in Figure 6 is only for illustration. By reasonably setting the number and position of the side heating elements 7, the temperature uniformity of the multiple rows and layers of saggers inside the furnace body 1 can be further ensured.

[0061] Referring to Figure 6, in an optional embodiment, a glass plate 8 is fixed to the side of the mounting groove 11 near the interior of the furnace body 1 to isolate the side heating element 7 from the dust inside the furnace body 1. Since the sintering material of the roller furnace in this invention is lithium iron phosphate, which is corrosive during the sintering process, the glass plate 8 installed in front of the side heating element can prevent dust from entering and corroding the side heating element 7; at the same time, it can prevent the side heating element 7 from directly baking the nearest sagger, thus avoiding excessively high local temperatures in the sagger.

[0062] Referring to Figure 6, in an optional embodiment, a support structure 9 is provided above or / below the mounting groove 11 on the side wall of the furnace body 1. In this embodiment, the support structure 9 can be a silicon carbide square tube, used to support the bricks above the mounting groove 11. Therefore, the bricks in the mounting groove 11 below the support structure 9 are not subjected to force, and thus the bricks can be pulled out to facilitate the disassembly, assembly, and maintenance of the side heating element 7.

[0063] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0064] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A roller furnace, characterized in that, It includes a furnace body (1) and an air intake assembly (5) disposed at the bottom of the furnace body (1). The air intake assembly (5) includes at least two layers of air passages disposed along the height direction of the furnace body (1). The air intake assembly (5) is used to preheat the gas that is introduced into the furnace body (1) through the air passages. Each layer of the airway includes at least two airway passages (51). The airway passages (51) are arranged in a coiled manner in the plane of the corresponding layer. The airway passages (51) of adjacent layers correspond one-to-one. The airway passage (51) includes an air inlet and an air outlet. The air outlet of the airway passage (51) located in the lower layer is connected to the air inlet of the corresponding airway passage (51) located in the upper layer.

2. The roller furnace according to claim 1, characterized in that, At least one of the airway passages (51) includes a plurality of alternating straight segments (511) and bends (512), with two straight segments (511) connected to the same bend (512) being perpendicular to each other, and the non-common straight segments (511) of two adjacent bends (512) being parallel to each other; The airway passage (51) includes a first radial section (511) and a second radial section (511) that are adjacent to each other. The gas flow direction in the two radial sections (511) adjacent to the first radial section (511) is the same, and the gas flow direction in the two radial sections (511) adjacent to the second radial section (511) is opposite.

3. The roller furnace according to claim 1, characterized in that, At least one of the airway passages (51) includes a plurality of alternating straight segments (511) and bends (512), with two straight segments (511) connected to the same bend (512) being perpendicular to each other, and two non-common straight segments (511) of two adjacent bends (512) being parallel to each other; Among them, the gas flow directions in the two adjacent radial sections (511) are opposite.

4. The roller furnace according to claim 1, characterized in that, The airway passage (51) has a concave corner and a convex corner at the coiling point, and the concave corner and / or convex corner are chamfered; And / or, the air outlets of the uppermost air passage (51) are distributed on the target central axis of the furnace body (1); And / or, the air outlet and air inlet of the air passage (51) located in the non-uppermost layer are both distributed on the side of the furnace body (1); And / or, the air intake assembly (5) is constructed of brickwork, with ceramic plates laid on the side of the brickwork facing the air passage (51).

5. The roller furnace according to claim 1, characterized in that, The top of the furnace body (1) is provided with a plurality of independent exhaust chimneys (6). The exhaust chimneys (6) include a first exhaust pipe (61) connected to the furnace body (1), a second exhaust pipe (62) not collinear with the axis of the first exhaust pipe (61), and a third exhaust pipe (63) connecting the first exhaust pipe (61) and the second exhaust pipe (62). The second exhaust pipe (62) is provided with a slide valve (64).

6. The roller furnace according to claim 5, characterized in that, The third exhaust pipe (63) has an inspection port (65) at one end away from the first exhaust pipe (61), and the third exhaust pipe (63) has an inclined angle that allows dust to flow toward the inspection port (65).

7. The roller furnace according to claim 1, characterized in that, It also includes a side heating element (7) with independently controllable temperature. The side wall of the furnace body (1) is provided with a mounting groove (11), and the side heating element (7) is detachably installed in the mounting groove (11).

8. The roller furnace according to claim 7, characterized in that, Multiple side heating elements (7) are provided, and the installation position of the side heating elements (7) is consistent with the height position of the bottom of each odd-numbered layer of saggers located in the furnace body (1).

9. The roller furnace according to claim 7, characterized in that, A glass plate (8) is fixed on the side of the mounting groove (11) near the inside of the furnace body (1) to isolate the side heating element (7) from the dust inside the furnace body (1); And / or, a support structure (9) is provided above or below the mounting groove (11) on the side wall of the furnace body (1).

10. The roller furnace according to any one of claims 1-9, characterized in that, The furnace body (1) is provided with a support mechanism (4) that supports at least two layers of saggers. And / or, the furnace body (1) is provided with a support mechanism (4) for carrying at least two rows of saggers.

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