Roller furnace

Abstract

The roller bed furnace comprises a furnace body and a gas inlet assembly arranged at the bottom in the furnace body, the gas inlet assembly comprises at least two layers of gas channels arranged in the height direction of the furnace body, and the gas inlet assembly is used for preheating gas introduced into the furnace body through the gas channels; each layer of air passages comprises at least two air passage passages, the air passage passages are arranged in the plane of the corresponding layer in a coiling manner, the air passage passages of the adjacent layers of air passages are in one-to-one correspondence, and each air passage passage comprises an air inlet and an air outlet; and the air outlet of the air passage on the lower layer is communicated with the air inlet of the corresponding air passage on the upper layer. When gas enters the bottom of the roller bed furnace, the gas is preheated through the gas channel in the gas inlet assembly and then enters the furnace, so that the temperature difference between the gas temperature and the temperature in the hearth can be reduced as much as possible, the uniformity of the temperature in the hearth is effectively ensured, and the sintering quality is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of roller hearth furnaces, and in particular relates to a roller hearth furnace. Background Art

[0002] Roller furnace is an industrial heating equipment, widely used in new energy, lithium battery, building materials and other industries. Its basic structure usually includes feeding system, roller, heating zone, cooling zone, discharging system and control system. The roller is composed of multiple rollers, which can support and transport the workpiece. The furnace provides heat through burners or electric heating elements, so that the workpiece reaches the required temperature during the movement to achieve sintering and other process requirements.

[0003] Lithium iron phosphate is a common raw material for lithium batteries and needs to be sintered in a roller furnace. During the sintering process, lithium iron phosphate is usually placed in a sagger for sintering. The sintering process is one of the core processes in lithium battery manufacturing, and the temperature uniformity in the furnace is a key factor in the sintering results of the material. If the temperature uniformity is poor and the temperature fluctuates greatly, the batches of lithium iron phosphate fired will vary greatly, and the material structure and performance will be unstable. Therefore, it is crucial to control the temperature stability and uniformity in the furnace during the sintering process. In order to improve the sintering efficiency of lithium iron phosphate, multiple rows and layers of saggers may be placed in the furnace at one time, which puts higher requirements on the uniformity of the temperature in the furnace.

[0004] In the prior art, the bottom air intake method used in roller hearth furnaces is to use an air intake pipeline or an air duct reserved by the bottom bricks to blow air directly into the furnace. This air intake method causes cold air with lower temperature to enter the furnace directly from the bottom of the furnace body, making the atmosphere in the lower part of the furnace lower in temperature than that in the upper part. In particular, when multiple rows and multiple layers of saggers need to be accommodated in the furnace, strict control of temperature uniformity is required.

[0005] Therefore, in view of the above technical problems, it is necessary to provide a roller furnace. Summary of the invention

[0006] The object of the present invention is to provide a roller furnace which can solve the problem that the lower temperature cold air directly enters the furnace from the lower part of the furnace body, resulting in inconsistent temperatures of saggers at different positions and affecting the sintering quality of materials.

[0007] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0008] A roller furnace, comprising a furnace body, an air intake assembly arranged at the bottom of the furnace body, the air intake assembly comprising at least two layers of air ducts arranged along the height direction of the furnace body, the air intake assembly being used to preheat the gas introduced into the furnace body through the air ducts;

[0009] Each layer of the airway includes at least two airway passages, and the airway passages are coiled in the plane of the corresponding layer. The airway passages of the airways in adjacent layers correspond to each other one by one. The airway passages include an air inlet and an air outlet, and 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.

[0010] In one or more embodiments of the present invention, at least one of the airway passages comprises a plurality of straight segments and curved segments arranged alternately, two straight segments connected to the same curved segment are perpendicular to each other, and non-common straight segments of two adjacent curved segments are parallel to each other;

[0011] The airway passage comprises a first straight section and a second straight section adjacent to each other, wherein the gas flow directions in the two straight sections adjacent to the first straight section are the same, and the gas flow directions in the two straight sections adjacent to the second straight section are opposite.

[0012] In one or more embodiments of the present invention, at least one of the airway passages comprises a plurality of alternating straight segments and bent segments, two straight segments connected to the same bent segment are perpendicular to each other, and two non-common straight segments of two adjacent bent segments are parallel to each other;

[0013] The gas flow directions in two straight sections adjacent to the same straight section are opposite.

[0014] In one or more embodiments of the present invention, the airway passage is formed with a inner corner and a outer corner at the coiling position, and the inner corner and / or the outer corner are chamfered;

[0015] and / or, the gas outlets of the gas passage located at the uppermost layer are distributed on the target central axis of the furnace body;

[0016] And / or, the air outlet and the air inlet of the air passage located at a non-uppermost layer are distributed at the side of the furnace body;

[0017] And / or, the air intake assembly is built with bricks, and a ceramic plate is laid on one side of the bricks facing the airway passage.

[0018] In one or more embodiments of the present invention, a plurality of independent exhaust chimneys are provided on the top of the furnace body, and the exhaust chimney includes a first exhaust pipe connected to the furnace body, a second exhaust pipe which is not colinear with the axis of the first exhaust pipe, and a third exhaust pipe connecting the first exhaust pipe and the second exhaust pipe, and the second exhaust pipe is provided with a gate valve.

[0019] In one or more embodiments of the present invention, an inspection port is provided at one end of the third exhaust pipe away from the first exhaust pipe, and the third exhaust pipe has an inclination angle that allows dust to flow toward the inspection port.

[0020] In one or more embodiments of the present invention, the roller furnace further comprises a side heating element of which the temperature can be independently controlled, and a mounting groove is provided on the side wall of the furnace body, and the side heating element is detachably mounted in the mounting groove.

[0021] In one or more embodiments of the present invention, a plurality of side heating elements are provided, and the installation positions of the side heating elements are consistent with the height positions of the bottoms of each odd-numbered layer of saggers in the furnace body.

[0022] In one or more embodiments of the present invention, a glass plate is fixed to one side of the mounting groove close to the inside of the furnace body, so as to isolate the side heating element from dust in the furnace body;

[0023] And / or, a supporting structure is arranged above or below the mounting groove of the side wall of the furnace body.

[0024] In one or more embodiments of the present invention, a carrying mechanism for carrying at least two layers of saggers is provided in the furnace body;

[0025] And / or, a supporting mechanism for supporting at least two rows of saggers is arranged in the furnace body.

[0026] Compared with the prior art, when the roller furnace of the present invention is inletted at the bottom, the gas is first preheated through the gas channel in the gas inlet assembly before entering the furnace, thereby minimizing the temperature difference between the gas temperature and the temperature in the furnace, effectively ensuring the uniformity of the temperature in the furnace, thereby ensuring the sintering quality. Among them, the number of gas channel layers and the winding arrangement of each gas channel passage can prolong the retention time of the gas in the gas channel to fully preheat the gas and ensure the uniformity of the temperature in the furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A front view of a roller hearth furnace in one embodiment of the present invention;

[0029] Figure 2 A side view of a roller hearth furnace in one embodiment of the present invention;

[0030] Figure 3 It is a schematic diagram of the structure of the bottom airway in the air intake assembly in one embodiment of the present invention;

[0031] Figure 4It is a schematic diagram of the structure of the top air duct in the air intake assembly in one embodiment of the present invention;

[0032] Figure 5 for Figure 1 The enlarged schematic diagram at A in the middle;

[0033] Figure 6 for Figure 2 The enlarged schematic diagram of point B in the middle;

[0034] Figure 7 Schematic diagram of the structure of the middle heating element in one embodiment of the present invention.

[0035] Description of main reference numerals:

[0036] 1. Furnace body; 11. Mounting groove; 2. Upper heating element; 3. Lower heating element; 4. Carrying mechanism; 5. Air intake assembly; 51. Airway 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 DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0038] Reference Figure 1 and Figure 2 The roller furnace in one embodiment of the present invention comprises a furnace body 1, an upper heating element 2 and a lower heating element 3 installed in the furnace body 1, and a supporting mechanism 4 arranged between the upper heating element 2 and the lower heating element 3. The supporting mechanism 4 comprises a plurality of conveying rollers for conveying a sagger filled with lithium iron phosphate. The supporting mechanism 4 allows the sagger to pass through different temperature zones in the furnace body 1 to complete the sintering of the lithium iron phosphate.

[0039] In order to improve the sintering efficiency of lithium iron phosphate, a supporting mechanism 4 for supporting at least two layers of saggers is provided in the furnace body 1; and / or, a supporting mechanism 4 for supporting at least two rows of saggers is provided in the furnace body 1. In this embodiment, multiple rows and multiple layers of saggers are provided on the supporting mechanism 4, and multiple lithium iron phosphates can be sintered at the same time. Among them, the saggers on the supporting mechanism 4 can be 6 rows and 2 layers, or 6 rows and 3 layers, or 6 layers and multiple rows, etc.

[0040] Reference Figure 1 and Figure 3The roller furnace in this embodiment also includes an air intake assembly 5 arranged at the bottom of the furnace body 1, and the air intake assembly 5 includes at least two layers of air ducts arranged 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 duct; each layer of the air duct includes at least two air duct passages 51, and the air duct passages 51 are coiled in the plane of the corresponding layer, and the air duct passages 51 of the adjacent layers of the air duct correspond to each other one by one. The air duct passages 51 include an air inlet and an air outlet, and the air outlet of the air duct passage 51 located in the lower layer is connected to the air inlet of the corresponding air duct passage 51 located in the upper layer.

[0041] When the roller furnace is in operation, the gas entering from the air inlet at the bottom of the furnace body 1 enters the furnace after being preheated through the air duct in the air inlet assembly 5. Since the air duct passage 51 is arranged in a winding manner and has at least two layers in the height direction, the gas can be prevented from directly entering the furnace. The number of layers of the air duct and the number of air passages can extend the retention time of the gas in the air duct, thereby ensuring that the temperature of the gas finally flowing out of the air outlet does not have a significant temperature difference compared to the temperature in the furnace, thereby ensuring the uniformity of the temperature in the furnace, thereby ensuring the sintering quality.

[0042] Reference Figure 3 and Figure 4 In this embodiment, the present invention is explained by taking two layers of airways, each layer of airways being provided with three airway passages 51 as an example, which does not represent a limitation on the number of airway layers and the number of airway passages 51 in the present invention.

[0043] Specifically, refer to Figure 3 , at least one airway passage 51 includes a plurality of straight sections 511 and bent sections 512 arranged alternately, two straight sections 511 connected to the same bent section 512 are perpendicular to each other, and non-common straight sections 511 of two adjacent bent sections 512 are parallel to each other;

[0044] The airway passage 51 includes a first straight section and a second straight section adjacent to each other. The gas flow directions in the two straight sections 511 adjacent to the first straight section are the same, and the gas flow directions in the two straight sections 511 adjacent to the second straight section 511 are opposite.

[0045] Reference Figure 4 At least one airway passage 51 includes a plurality of alternating straight sections 511 and bent sections 512, wherein two straight sections 511 connected to the same bent section 512 are perpendicular to each other, and two non-common straight sections 511 of two adjacent bent sections 512 are parallel to each other; wherein the gas flow directions in two straight sections 511 adjacent to the same straight section 511 are opposite.

[0046] By coordinating the straight section 511 and the bent section 512, the airway forms a coiled structure, so that the internal space of the air intake component 5 can be fully utilized, thereby ensuring that the gas travels as long as possible in each layer of the airway passage 51 to ensure the preheating effect of the gas.

[0047] Reference Figure 3 and Figure 4 The gas passage 51 forms a concave angle and a convex angle at the winding part, and the concave angle and / or the convex angle are chamfered. In this embodiment, the winding part is the connection part between the straight section 511 and the bent section 512. The chamfering at the concave angle and / or the convex angle can reduce the pressure loss of the gas flow when passing through the gas passage bent section 512, thereby ensuring that the gas can enter the furnace with sufficient pressure.

[0048] Reference Figure 4 The gas outlets of the uppermost gas passage 51 are distributed on the target central axis of the furnace body 1. By reasonably setting the gas outlet positions of the uppermost gas passage 51, the influence of the gas entering the furnace on the original gas inside the furnace can be further reduced.

[0049] Reference Figure 3 The gas outlet and the gas inlet of the gas passage 51 located at the non-uppermost layer are distributed at the side of the furnace body 1, so as to prolong the retention time of the gas in the gas passage 51, thereby enhancing the preheating effect of the gas.

[0050] Reference Figure 3 and Figure 4 In this embodiment, the air intake assembly 5 is built with bricks, and a ceramic plate is laid on the side of the bricks facing the airway passage 51. Since conventional refractory bricks are easily powderized under high temperature conditions, a large amount of dust will be formed in the airway. The dust blown into the furnace will pollute the atmosphere in the furnace. The remaining powder deposited inside the airway may reduce the gas flow in the airway or even block the airway. Laying ceramic plates around the airway can effectively avoid the occurrence of the above phenomenon, and at the same time can further reduce the friction between the airflow and the airway to ensure the gas pressure. In other embodiments, the air intake assembly 5 can also be directly set as a pipeline.

[0051] Reference Figure 1 and Figure 5 A plurality of mutually independent exhaust chimneys 6 are arranged on the top of the furnace body 1, and the exhaust chimney 6 includes a first exhaust pipe 61 connected to the furnace body 1, a second exhaust pipe 62 which is not arranged colinearly 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, and the second exhaust pipe 62 is provided with a gate valve 64.

[0052] Therefore, the third exhaust pipe 63 is provided so that the dust contained in the gas exhausted from the first exhaust pipe 61 can 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 are arranged so that the gas exhausted from the furnace body 1 will not directly impact the gate valve 64, thereby extending the service life of the gate valve 64.

[0053] Reference Figure 5 An inspection port 65 is provided at one end of the third exhaust pipe 63 away from the first exhaust pipe 61, and the third exhaust pipe 63 has an inclination angle that allows dust to flow toward the inspection port 65. The inspection port 65 is provided with an inspection cover, and when the inspection cover is opened, the dust deposited in the third exhaust pipe 63 flows toward the inspection port 65, thereby reducing the difficulty of cleaning the deposited dust.

[0054] Reference Figure 5 In an optional embodiment, an inspection port 65 may also be provided at one end of the first exhaust pipe 61 away from the furnace body 1. When a special situation occurs, the inspection port 65 may also 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, so that more complex situations can be handled.

[0055] Reference Figure 6 and Figure 7 The roller furnace of this embodiment further includes a side heating element 7 whose temperature can be independently controlled. The side wall of the furnace body 1 is provided with a mounting groove 11, and the side heating element 7 is detachably mounted in the mounting groove 11. Specifically, in this embodiment, the side wall of the furnace body 1 is formed by stacking bricks, one of which can be provided with a mounting groove 11, and the heating end of the side heating element 7 is located in the mounting groove 11.

[0056] Since multiple rows and multiple layers of saggers are arranged in the roller furnace, the space in the furnace body 1 is correspondingly larger. Relying on a single upper heating element 2 and a lower heating element 3 may result in large temperature differences of materials in the same batch of saggers, which may easily lead to a reduction in the yield of sintered materials.

[0057] Therefore, the coordinated arrangement of the side heating element 7, the upper heating element 2 and the lower heating element 3 can ensure the uniformity of the temperature in the furnace body 1 and improve the adaptability to the heating of the multi-row multi-layer roller furnace. The side heating element 7 is controlled separately and can be adjusted according to the actual temperature, thereby avoiding the situation where the local temperature on the side of the furnace body 1 is too high.

[0058] Reference Figure 6 A plurality of side heating elements 7 are provided, and the installation positions of the side heating elements 7 are consistent with the height positions of the bottoms of each odd-numbered layer of saggers in the furnace body 1 . Figure 6The position of the middle side heating element 7 is only for illustration. By properly setting the number and position of the side heating elements 7, the uniformity of the temperature of the saggers in multiple rows and multiple layers in the furnace body 1 can be further ensured.

[0059] Reference Figure 6 In an optional embodiment, a glass plate 8 is fixed on one side of the mounting groove 11 close to the inside of the furnace body 1, which is used to isolate the side heating element 7 from the dust in the furnace body 1. Since the sintering material of the roller furnace in the present invention is lithium iron phosphate, which is corrosive during the sintering process, the glass plate 8 is installed in front of the side heating to prevent dust from invading and corroding the side heating element 7; at the same time, the side heating element 7 is prevented from directly baking the nearest sagger, thereby avoiding excessively high local temperature of the sagger.

[0060] Reference Figure 6 In an optional embodiment, a support structure 9 is provided above or / below the mounting groove 11 of the side wall of the furnace body 1. In this embodiment, the support structure 9 can be a silicon carbide square tube, which is 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, so the bricks can be pulled out, so as to facilitate the disassembly and maintenance of the side heating element 7.

[0061] It will be apparent to those skilled in the art that the 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 the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0062] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A roller hearth furnace, characterized in that: It comprises a furnace body (1), and an air intake assembly (5) arranged at the bottom of the furnace body (1), wherein the air intake assembly (5) comprises at least two layers of air passages arranged along the height direction of the furnace body (1), and the air intake assembly (5) is used to preheat the gas introduced into the furnace body (1) through the air passages; Each layer of the airway comprises at least two airway passages (51), and the airway passages (51) are arranged in a coiled manner within the plane of the corresponding layer. The airway passages (51) of the airways of adjacent layers correspond to each other one by one. The airway passages (51) comprise an air inlet and an air outlet, and 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 hearth furnace according to claim 1, characterized in that: At least one of the airway passages (51) comprises a plurality of straight sections (511) and bent sections (512) arranged alternately, two straight sections (511) connected to the same bent section (512) are perpendicular to each other, and non-common straight sections (511) of two adjacent bent sections (512) are parallel to each other; The airway passage (51) comprises a first straight section (511) and a second straight section (511) adjacent to each other, wherein the gas flow directions in the two straight sections (511) adjacent to the first straight section (511) are the same, and the gas flow directions in the two straight sections (511) adjacent to the second straight section (511) are opposite.

3. The roller hearth furnace according to claim 1, characterized in that: At least one of the airway passages (51) comprises a plurality of alternating straight sections (511) and bent sections (512), two straight sections (511) connected to the same bent section (512) are perpendicular to each other, and two non-common straight sections (511) of two adjacent bent sections (512) are parallel to each other; The gas flow directions in two straight sections (511) adjacent to the same straight section (511) are opposite.

4. The roller hearth furnace according to claim 1, characterized in that: The airway passage (51) is formed with a inner corner and an outer corner at the winding position, and the inner corner and / or the outer corner are chamfered; and / or, the gas outlets of the gas passage (51) located at the uppermost layer are distributed on the target central axis of the furnace body (1); and / or, the air outlet and the air inlet of the air passage (51) located at a non-uppermost layer are both distributed at the side of the furnace body (1); And / or, the air intake assembly (5) is built with bricks, and a ceramic plate is laid on one side of the bricks facing the air passage (51).

5. The roller hearth furnace according to claim 1, characterized in that: A plurality of mutually independent exhaust chimneys (6) are arranged on the top of the furnace body (1), and the exhaust chimney (6) comprises a first exhaust pipe (61) connected to the furnace body (1), a second exhaust pipe (62) arranged not colinearly 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), and the second exhaust pipe (62) is provided with a gate valve (64).

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

7. The roller hearth furnace according to claim 1, characterized in that: It also comprises a side heating element (7) whose temperature can be independently controlled. The side wall of the furnace body (1) is provided with a mounting groove (11), and the side heating element (7) is detachably mounted in the mounting groove (11).

8. The roller hearth furnace according to claim 7, characterized in that: A plurality of the side heating elements (7) are provided, and the installation positions of the side heating elements (7) are consistent with the height positions of the bottoms of each odd-numbered layer of saggers located in the furnace body (1).

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

10. The roller hearth furnace according to any one of claims 1 to 9, characterized in that: A carrying mechanism (4) for carrying at least two layers of saggers is arranged in the furnace body (1); And / or, a supporting mechanism (4) for supporting at least two rows of saggers is arranged in the furnace body (1).

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