Container type furnace bar frame

Abstract

The utility model discloses a container type furnace fence frame, which belongs to the technical field of heat treatment appliances, a bottom plate and a limiting plate are connected through a plurality of vertical rods, and the container type furnace fence frame is integrally of a latticed rectangular fence frame structure and is used for containing a plurality of workpieces and keeping the workpieces arranged at equal intervals in the heat treatment process. The bottom plate is provided with a permeable source structure for permeability of the workpiece and a positioning part for fixing the vertical rod, and the positioning part adopts an embedded structure to ensure stable installation of the vertical rod. Limiting holes are evenly distributed in the limiting plate and used for inserting workpieces and achieving accurate limiting, and stable installation is formed through cooperation of the positioning structure and the vertical rods. The bottom end and the middle section of the vertical rod are provided with embedded matching structures which are firmly connected with the bottom plate and the limiting plate, and stable supporting is provided. The connecting rods are connected with the two rows of vertical rods in the middle, the overall rigidity of the frame structure is further enhanced, and detachable constraint on the limiting plates is formed. The fence frame facilitates orderly loading and accurate positioning of workpieces, effectively avoids collision or dislocation of the workpieces in the furnace loading process, and improves uniformity and quality of heat treatment.

Description

TECHNICAL FIELD

[0001] The utility model belongs to a technical scheme in the technical field of heat treatment appliance, specifically, the utility model relates to a furnace fence frame capable of containing multiple workpieces and loading into a furnace, in particular to a containerized furnace fence frame allowing workpieces to be arranged at equal intervals. BACKGROUND

[0002] The piston matched with the mine impactor is usually made of low alloy structural steel, and after finishing, the performance optimization of the final product needs to be completed through a heat treatment process. The heat treatment process includes steps such as carburizing, quenching, and tempering, aiming to improve the hardness, wear resistance, and service life of the piston. However, in the prior art, the heat treatment is generally carried out by loading the workpieces in bulk into the furnace. This loading method is simple to operate, has high loading efficiency, and is suitable for batch production, but it also has the following outstanding problems:

[0003] Under the bulk stacking state, the contact between the workpieces inevitably causes surface scratches and scratches, resulting in appearance defects of the piston. Such defects not only affect the product quality, but also may lead to the complication of subsequent process flow and the increase of production cost.

[0004] The bulk stacked workpieces are arranged in disorder, and there may be overlapping areas between adjacent workpieces, resulting in insufficient carburization effect in these areas and affecting the consistency of the piston surface hardness. This problem directly weakens the overall performance of the product, especially the wear resistance and fatigue resistance.

[0005] The disordered arrangement of bulk workpieces in the furnace easily causes uneven heat flow distribution, further causing the difference in heating conditions of the workpieces, thereby affecting the consistency of the heat treatment effect. Such defects may lead to unstable performance of batch products, increasing the difficulty of quality control.

[0006] Although the existing patent technology such as CN102703908A proposes a heat treatment method for impact pistons, covering processes such as carburizing, quenching, and tempering, it does not provide specific solutions for the design of furnace frames, so it cannot effectively solve the problems of surface scratches and uneven carburization during the loading of bulk workpieces into the furnace.

[0007] In view of the above problems, the industry has been exploring effective solutions to optimize the loading method to reduce workpiece damage, improve carburization uniformity, and improve the consistency of heat treatment quality. Therefore, an innovative containerized furnace fence frame design is proposed to arrange workpieces in order, optimize loading efficiency and heat treatment effect, thereby overcoming the shortcomings of the prior art, which is particularly necessary and urgent. CONTENT OF THE UTILITY MODEL

[0008] The utility model mainly aims at the problem of disorderly stacking work of prior art, workpiece surface is easily damaged, carburizing effect is uneven, heat treatment consistency is poor and leads to heat treatment quality difference, proposes a kind of structure simple, workpiece arrangement order, charge efficiency is high, unloading is easy, and heat treatment quality consistency good container type furnace fence frame.

[0009] In order to solve the above problems, the utility model provides a kind of container type furnace fence frame, including bottom plate and the spacing plate matched with bottom plate, the bottom plate is connected with spacing plate by multiple vertical rods, and the vertical rod is connected with connecting rod between vertical rod;

[0010] The bottom plate, spacing plate, vertical rod and connecting rod are in the overall grid-shaped rectangular fence structure, for containing multiple workpieces and keeping equidistant arrangement in heat treatment process;

[0011] The bottom plate is provided with the source structure for the permeability of workpiece and the positioning part for the fixing of vertical rod, and the positioning part has embedded structure;

[0012] The spacing plate has uniformly distributed spacing holes for inserting workpieces and realizing position limiting, and is installed by cooperating with vertical rod through positioning structure;

[0013] The vertical rod is used to form support between bottom plate and spacing plate, and the bottom end and middle section of vertical rod are provided with embedded matching structure, which is connected with bottom plate and spacing plate to form stable support;

[0014] The connecting rod is used to connect two rows of vertical rods in the middle, thereby forming detachable constraint structure for spacing plate.

[0015] As preferably, the bottom plate and spacing plate are matched rectangular plate and the plane size is equal, through the accurate matching of the size of bottom plate and spacing plate, the stability and strength of the overall structure of furnace fence frame are ensured, so that workpieces can keep uniform spacing arrangement in heat treatment process, thereby avoiding arrangement error and uneven heating of workpieces caused by asymmetric structure, and the quality consistency of heat treatment is significantly improved.

[0016] As preferably, the source structure is uniformly distributed through-hole on the bottom plate surface, the positioning part includes equidistantly arranged counterbore arranged on the four edge frame surface of bottom plate, the female tenon recessed radially in the counterbore, through the through-hole of bottom plate, the spacing hole and process hole of spacing plate and the ordered interval arrangement of vertical rod and workpiece, the positioning installation of workpiece and the permeability and homogeneity in heat treatment process are realized, the through-hole uniformly distributed on bottom plate and the spacing hole and process hole structure on spacing plate greatly improve the permeability of heat flow in furnace, ensure that each workpiece can be heated evenly in heat treatment process, reduce heat treatment time, and improve production efficiency. Through the supporting property of through-hole design and the auxiliary function of process hole, the thermal deformation of workpiece can also be effectively reduced, and product quality is improved.

[0017] As preferably, the limiting plate is spliced by two rectangular plates with same shape and size, the butt joint is arranged at the folding position of the length dimension, the limiting hole is a uniformly distributed circular limiting hole on the plate surface of the limiting plate, the positioning structure is a hollow triangular process hole added on the plate surface between the limiting holes at the edge and a hollow quadrilateral process hole added on the plate surface between the remaining limiting holes, in addition, there are guide holes arranged according to the position of the counterbore of the base plate on the frame surface of the four edges of the limiting plate, the limiting plate is designed by splicing two rectangular plates, which increases the flexibility of assembly and disassembly, reduces the risk of thermal deformation in the heat treatment process, and thus reduces the strength requirement of the limiting plate. In addition, the circular limiting hole, triangular process hole and quadrilateral process hole on the limiting plate jointly optimize the positioning and arrangement of the workpiece, which helps to realize fast operation when loading the furnace, improve the assembly and disassembly efficiency, and further reduce the heat consumption in the heat treatment process.

[0018] As preferably, the vertical rod is a straight rod, the embedded fitting structure is a radial male tenon arranged on the bottom end and the middle section outer wall, the bottom end male tenon of the vertical rod is inserted into the counterbore of the base plate, the uniformly distributed vertical rods form a framework that supports the limiting plate together from the male tenon on the middle section outer wall, the two rows of vertical rods in the middle are connected by connecting rods to form a detachable constraint structure for the two limiting plates, through the embedded fitting structure design of the bottom end and the middle section of the vertical rod, the stable connection between the vertical rod and the base plate and the limiting plate is ensured, and the structural strength and durability of the overall framework are improved. This structure also allows the disassembly and assembly of the limiting plate to be more convenient, which helps daily maintenance and cleaning, improves the service life and working efficiency of the equipment.

[0019] As preferably, the female tenon transverse section is a cross-shaped recess, the male tenon transverse section is a cross-shaped protrusion, the female tenon and the male tenon are embedded with each other, the cross-shaped embedded structure provides better anti-sliding and anti-rotation capability than the traditional circular or rectangular section, which significantly improves the stability and impact resistance of the structure. At the same time, this structure also facilitates the rapid assembly and disassembly of the components, reduces the maintenance cost and the complexity of assembly and disassembly operation.

[0020] As preferably, the uniformly distributed through hole on the base plate surface is a polygonal hole, the inscribed circle diameter is at least 10mm smaller than the workpiece outer diameter, to ensure the stable support and permeability of the base plate to the workpiece, by controlling the inscribed circle diameter of the through hole of the base plate to be at least 10mm smaller than the workpiece outer diameter, the stable support of the workpiece on the base plate is ensured, which prevents the workpiece from moving during the heat treatment process, and the safety and heat flow permeability of the heat treatment process are improved, and the heat treatment effect is optimized.

[0021] As preferably, the uniformly distributed limiting holes on the surface of the limiting plate are circular holes, and the inner diameter of the circular holes is at least 2.0 mm larger than the outer diameter of the workpiece, which not only ensures the smoothness of the workpiece during loading and unloading, but also effectively reduces the friction and damage of the workpiece surface and the limiting hole, further improving the appearance quality and service life of the workpiece.

[0022] As preferably, the thickness of the limiting plate is thinner than that of the bottom plate, and the thickness difference is at least 3 times, the limiting plate adopts a thin-walled design, which reduces the thickness of the limiting plate by at least three times compared with the thickness of the bottom plate, which not only reduces the material cost, but also reduces the heat loss of the limiting plate during heat treatment. This structural optimization not only realizes the function, but also further improves the cost-effectiveness and energy utilization.

[0023] Compared with the prior art, the utility model has the beneficial technical effects:

[0024] The utility model discloses a limiting plate is set up, and workpiece can be arranged in order and fixed according to uniform spacing, and the problem of workpiece surface knock and scratch caused by disordered arrangement in the existing bulk storage mode is completely avoided, thereby effectively improving product appearance quality and the reliability of subsequent process.

[0025] The limiting hole on the limiting plate installs workpiece, thereby ensuring that the spacing between workpieces is consistent, avoiding the surface of adjacent workpieces from overlapping, and significantly improving the uniformity in the carburizing process. This improvement directly enhances the consistency of the surface hardness of the piston, optimizes its wear resistance and fatigue resistance, ensures that the workpiece is homogenously heat treated after entering the furnace, thereby improving the overall performance of the product.

[0026] The bottom plate, the limiting plate, the vertical rod and the connecting rod are in the overall grid-shaped rectangular frame structure, the grid design of the furnace frame is optimized, the uniform distribution of the workpiece in the heat treatment furnace is realized, the problem of uneven heat flow distribution is effectively improved, the consistency of the batch workpiece heat treatment effect is significantly improved, and the fluctuation of product quality is reduced.

[0027] The limiting plate adopts a split structure, which is convenient for installation and disassembly, and most importantly, reduces the thermal deformation of the limiting plate, thereby reducing the strength requirement of the limiting plate, thinning the limiting plate, reducing the production cost, and reducing the heat loss during heat treatment.

[0028] The vertical rod, the bottom plate and the limiting plate are firmly connected through the embedded structure, a stable support structure is constructed, the deformation resistance and durability of the furnace frame during long-term use are ensured, the service life of the equipment is prolonged, and the equipment replacement frequency is reduced.

[0029] The bottom plate, the limiting plate, the vertical rod and the connecting rod adopt a modular combination mode, assembly and disassembly are very convenient, cleaning and maintenance are facilitated, the universality and maintenance efficiency of the furnace frame are improved, and the demand of industrialized batch production is met. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structural perspective view of the present application.

[0031] Figure 2 is Figure 1 is a structural perspective view of the base plate shown in

[0032] Figure 3 is Figure 2 is a structural perspective view of the counterbore shown in

[0033] Figure 4 is Figure 1 is a structural perspective view of the limiting plate 2 shown in

[0034] Figure 5 is Figure 1 is a structural perspective view of the vertical rod shown in

[0035] Figure 6 is Figure 1 is a structural perspective view of the connecting rod shown in

[0036] Figure 7 is a structural perspective view of the present application for placing workpieces.

[0037] In the figure: 1 - base plate, 1.1 - through hole, 1.2 - counterbore, 1.3 - female tenon, 2 - limiting plate, 2.1 - guide hole, 2.2 - limiting hole, 2.3 - triangular process hole, 2.4 - quadrilateral process hole, 3 - vertical rod, 3.1 - male tenon, 4 - connecting rod. DETAILED DESCRIPTION

[0038] The present application will be further explained and described below in conjunction with the drawings and examples.

[0039] Referring to the collection type furnace fence frame shown in Figure 1 , it is composed of a base plate 1, a limiting plate 2, a vertical rod 3 and a connecting rod 4 to form a grid-shaped rectangular fence cabinet, Figure 2 the base plate 1 shown in Figure 4The shown limiting plate 2 is a pair of rectangular plates, the two plates have equal planar size but unequal thickness, and it is specifically required that the thickness of the limiting plate 2 is thinner than the bottom plate 1, and the thickness difference is at least 3 times. The present embodiment is used for the piston carburizing treatment of a 5-ton mine impactor, and the number of integrated placement workpieces is 28 at a time, and the total weight is 15 kg. Since the bottom plate 1 directly bears the workpieces, it must have sufficient structural strength to meet the matching requirements, and the role of the limiting plate 2 in the structure is only to limit the assembly, so the thickness of the limiting plate 2 does not need to be too thick. Based on the above structural design principle, the thickness of the bottom plate 1 in the present embodiment is set to 30 mm, and the thickness of the limiting plate 2 is set to 10 mm. The through holes 1.1 uniformly distributed on the surface of the bottom plate 1 are polygonal holes, and the diameter of the inscribed circle is at least 10 mm smaller than the outer diameter of the workpiece. The outer diameter of the workpiece in the present embodiment is Φ100 mm, and the through hole 1.1 matched with the bottom plate 1 is a hexagonal hole as shown in Figure 2 The inscribed circle of the hole is 490 mm. The purpose of this structural design is to ensure that the bottom plate 1 can stably bear the workpiece, and cannot reduce the permeability of the workpiece at the installation position. The bottom plate 1 is provided with equidistantly arranged counterbores 1.2 on the surface of the four edges of the frame, as shown in Figure 3 The female tenon 1.3 is radially recessed in the counterbores 1.2. There are a total of 8 counterbores 1.2 on the surface of the bottom plate 1 in the present embodiment, and the counterbores 1.2 are used to position and arrange the vertical rods 3. The limiting plate 2 is shown in Figure 4 It is spliced from two rectangular plate blocks with the same shape and size, and the butt joint is located at the fold of the length dimension. The surface of the limiting plate 2 in the present embodiment is uniformly distributed with 28 circular limiting holes 2.2, of which 4 are horizontally arranged and 7 are vertically arranged. From the perspective of facilitating the loading and unloading of the workpiece, it is required in the structure that the inner diameter of the limiting hole 2.2 is at least 2.0 mm larger than the outer diameter of the workpiece, and the inner diameter of the limiting hole 2.2 in the present embodiment is 2.5 mm larger than the outer diameter of the workpiece. In order to further improve the permeability of the limiting plate 2 and reduce thermal deformation and heat loss, process holes are added to the limiting plate 2, triangular process holes 2.3 are added to the surface between the limiting holes 2.2 located at the edge, and quadrilateral process holes 2.4 are added to the surface between the remaining limiting holes 2.2. The guide holes 2.1 are arranged on the surface of the four edges of the frame according to the position of the counterbores 1.2 of the bottom plate 1, and the guide holes 2.1 directly gap-fit with the vertical rods 3 to realize the positioning and installation of the limiting plate 2. The vertical rod 3 is a straight rod as shown in Figure 5 The outer wall of the bottom end and the middle section is provided with a radially protruding male tenon 3.1.

[0040] When the container type furnace fence frame is assembled, first, the bottom tenon of the vertical rod 3 is inserted into the counterbore 1.2 of the bottom plate 1, and in this embodiment, there are 8 vertical rods 3, thereby forming a double-layer frame in which the vertical rods 3 are supported by the tenon on the middle section outer wall and the limiting plate 2. In order to further improve the rigidity and stability of the double-layer frame, the counterbore 1.2 of the bottom plate 1 is provided with a female tenon in a cross-shaped recessed structure, and the tenon on the bottom end and the middle section outer wall of the vertical rod 3 is in a cross-shaped protruding structure, and after installation, the female tenon and the tenon form a matching structure. The connecting rod 4 is directly installed on the two rows of vertical rods 3 in the middle, and the lap joint forms a detachable constraint structure for the two limiting plates 2. In addition, after the connecting rod 4 is installed, the overall rigidity of the container type furnace fence frame is increased, which is beneficial to the furnace loading and unloading operation and improves the heat treatment efficiency. Figure 6

[0041] When the container type furnace fence frame is actually applied, the workpieces are directly inserted into the limiting holes of the limiting plate 2, and as shown in the figure, 28 workpieces are collected. This container type furnace fence frame can realize position positioning when the workpieces are installed in place, and since the workpieces are orderly and arranged between each other, the workpieces are prevented from colliding with each other during furnace loading, and the heat treatment quality is improved. Figure 7

[0042] In order to facilitate the understanding of the above technical scheme of the utility model, the above technical scheme of the utility model is described in detail through a specific use mode.

[0043] ​​The specific assembly and working process are as follows: firstly, the male tenon 3.1 of the embedded fitting structure of the vertical rod 3 is inserted into the counterbore 1.2 of the positioning part of the bottom plate 1, and the male tenon 3.1 is firmly embedded with the female tenon 1.3 of the embedded fitting structure to form a stable support point; then the guide hole 2.1 of the positioning structure of the limiting plate 2 is aligned with the male tenon 3.1 of the middle section of the vertical rod, and the limiting plate 2 is gently pressed down to the middle section of the vertical rod 3, so that the limiting plate 2 uniformly covers all the vertical rods 3, and two splicing plates are used to splice to form a complete limiting plate 2, and the butt joint is ensured to be seamlessly matched; the connecting rod 4 is arranged between the middle two rows of the vertical rod 3, and is fixed to the male tenon part of the vertical rod 3 to increase the rigidity and stability of the overall frame, then the workpieces are inserted into the limiting holes 2.2 of the limiting plate 2, and each workpiece is sequentially loaded into the corresponding hole position, so that the workpieces are arranged in order and the spacing is uniform, and it is checked whether the workpieces are completely inserted into the through holes of the bottom plate and whether the workpieces are shaken in the hole position, so as to avoid position deviation in the heat treatment process due to loosening. Then the assembled grid type furnace fence frame is integrally moved to the heat treatment furnace together with the workpieces, a hoisting device is used to slowly put the furnace fence frame into the specified position in the furnace, so that the frame body is stably placed, and tilting or impact is avoided, the furnace temperature is adjusted according to the process requirement, the heat treatment process (such as carburizing, quenching or tempering) is started, the grid type structure enables the heat flow to uniformly penetrate around the workpieces, so that each workpiece is uniformly heated in the heat treatment process, and the through hole, process hole and other hole type structures of the bottom plate 1 and the limiting plate 2 greatly improve the permeability of the heat flow in the furnace, so as to avoid heat flow stagnation or deflection, the limiting hole fixes the position of the workpiece, prevents the workpieces from colliding with or scratching each other, improves the appearance quality, the equidistant arrangement avoids the overlapping phenomenon between the workpieces, ensures uniform carburizing layer and improves the consistency of surface hardness. After the heat treatment is completed, the hoisting device is used to integrally move the furnace fence frame out of the furnace, and the furnace fence frame is placed on a cooling table or a special area for cooling. In the cooling process, the workpieces are kept in the fixed state in the frame to avoid position deviation or thermal deformation of the workpieces due to rapid cooling.

[0044] In the description of the present application, it should be explained that the terms "upper", "lower" and the like indicate the position or location relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a specific position, structure and operation, therefore it cannot be understood as a limitation on the present application. Unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] It should be noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one from another entity or action, without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0046] The above description is merely that of the specific embodiments of the present application, and enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A kind of container type furnace fence frame, including bottom plate (1) and with bottom plate matched limiting plate (2), the bottom plate (1) is connected with limiting plate (2) by multiple vertical pole (3), the connecting rod (4) is connected between the vertical pole (3);Its characterized in that, The bottom plate (1), limiting plate (2), vertical pole (3) and connecting rod (4) are in the form of grid-shaped rectangular fence structure as a whole, for containing multiple workpieces and keeping equidistant arrangement in heat treatment process; The bottom plate (1) is provided with a source structure for the permeability of workpiece and a positioning part for vertical pole fixing, the positioning part has embedded structure; The limiting plate (2) has uniformly distributed limiting hole, for inserting and installing workpiece and realizing position limiting, and is installed by cooperating with vertical pole through positioning structure; The vertical pole (3) is used to form support between the bottom plate (1) and the limiting plate (2), and the bottom end and the middle section of the vertical pole (3) are provided with embedded matching structure, which is connected with the bottom plate and the limiting plate to form stable support; The connecting rod (4) is used to connect two rows of vertical poles (3) in the middle, thereby forming detachable constraint structure for the limiting plate (2).

2. The modular fire pit of claim 1, wherein, The bottom plate (1) and the limiting plate (2) are matched rectangular plates and the plane sizes are equal.

3. The modular fire pit of claim 1, wherein, The source structure is the uniformly distributed through hole (1.1) on the plate surface of the bottom plate (1), the positioning part includes the equidistantly arranged counterbores (1.2) provided on the plate surface of the four edge frame of the bottom plate (1), and the female tenon (1.3) is arranged in the radial recess in the counterbores (1.2).

4. The modular fire screen of claim 3, wherein, The limiting plate (2) is spliced from two rectangular plates with the same shape and size, the butt joint is arranged at the length dimension of the fold, the limiting hole is the uniformly distributed circular limiting hole (2.2) on the plate surface of the limiting plate (2), the positioning structure is the hollow triangular process hole (2.3) additionally arranged on the plate surface between the limiting holes (2.2) located at the edge and the hollow quadrilateral process hole (2.4) additionally arranged on the plate surface between the remaining limiting holes (2.2), and in addition, the limiting plate (2) is additionally provided with the guide hole (2.1) on the four edge frame of the plate surface according to the position of the counterbores (1.2) of the bottom plate (1).

5. The modular fire pit of claim 3, wherein, The vertical pole (3) is a straight pole, the embedded matching structure is the radial male tenon (3.1) arranged on the outer wall of the bottom end and the middle section, the bottom end male tenon (3.1) of the vertical pole (3) is inserted into the counterbores (1.2) of the bottom plate (1), the uniformly distributed vertical poles (3) form the frame for supporting the limiting plate (2) from the male tenons on the outer wall of the middle section, the two rows of vertical poles (3) in the middle are connected by the connecting rod (4) to constitute the detachable constraint structure for the two limiting plates (2).

6. The modular fire screen of claim 5, wherein, The female tenon (1.3) is in the form of cross-shaped recess in the transverse section, the male tenon (3.1) is in the form of cross-shaped protrusion in the transverse section, and the female tenon (1.3) and the male tenon (3.1) are embedded with each other.

7. The modular fire pit of claim 1, wherein, The uniformly distributed through hole (1.1) on the plate surface of the bottom plate (1) is polygonal hole, and the diameter of the inscribed circle is at least 10 mm smaller than the outer diameter of the workpiece to ensure the stable support and permeability of the bottom plate for the workpiece.

8. The modular fire pit of claim 1, wherein, The uniformly distributed limiting hole (2.2) on the plate surface of the limiting plate (2) is circular hole, and the inner diameter is at least 2.0 mm larger than the outer diameter of the workpiece to facilitate the loading and unloading of the workpiece.

9. The modular fire pit of claim 1, wherein, The thickness of the limiting plate (2) is thinner than that of the bottom plate (1), and the difference is at least 3 times.

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