Low-temperature furnace for carbon fiber production and carbon fiber production method

Abstract

The embodiment of the invention provides a low-temperature furnace for carbon fiber production and a carbon fiber production method, and relates to the technical field of carbon fiber production equipment. The invention discloses a low-temperature furnace for carbon fiber production. The low-temperature furnace comprises a furnace body, two connecting seat groups arranged on two opposite inner walls of the furnace body, a plurality of bayonet sockets, a plurality of double-plug electric heating tubes and a bracket, each connecting seat group comprises a plurality of connecting seats, the plurality of connecting seats are distributed along the length direction of the inner walls of the furnace body, and the plurality of connecting seats on the two opposite inner walls are arranged in a one-to-one correspondence manner; mounting holes which are communicated with each other are formed in each connecting seat and the side wall of the furnace body, and a bayonet socket is arranged in each mounting hole; each electric heating tube is inserted into the corresponding bayonet socket; the bracket is arranged in the furnace body, and a plurality of arc-shaped grooves are formed in the length direction of the bracket; each double-plug-in electric heating tube is composed of two electric heating short tubes, and the plug-in position of the two electric heating short tubes is arranged in one arc-shaped groove in a supported mode. According to the low-temperature furnace provided by the invention, the electric heating tube is convenient to disassemble and assemble, and axial and radial limiting can be realized.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber production equipment technology, and more specifically, to a low-temperature furnace for carbon fiber production and a carbon fiber production method. Background Technology

[0002] The heating element of the low-temperature furnace used in carbon fiber production is the core component for furnace temperature control. Its connection and sealing effect directly affects the temperature stability inside the furnace, as well as the efficiency and cost of equipment operation and maintenance. Existing technologies have several shortcomings, including: insufficient installation limits; the heating element is simply connected to the furnace wall via a sleeve without a precise axial limit structure, making it prone to displacement due to thermal expansion and contraction; lack of radial support, leading to wobbling and uneven heating over long-term use; inadequate insulation and sealing; the heating element is only wrapped with a single layer of rock wool, resulting in poor insulation and inadequate sealing, allowing heat loss and cold air infiltration; lack of a dedicated high-temperature sealing structure at the furnace wall connection, causing gas leaks and atmospheric fluctuations; difficult replacement; traditional heating elements are welded or bonded to the furnace wall, requiring cutting or prying for disassembly, taking up to 4 hours and easily damaging the furnace wall structure; weak tar resistance; tar is easily generated during low-temperature furnace operation, seeping into the heating element and corroding it; the furnace wall needs to be cleaned of particulate matter and tar every 24 hours, requiring maintenance every 3 months on average, and a batch of heating elements needs to be replaced every 6 months, resulting in short service life and low production efficiency.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The present invention aims to provide a low-temperature furnace for carbon fiber production and a carbon fiber production method, thereby improving at least one of the problems mentioned in the background art.

[0005] The embodiments of the present invention can be implemented as follows: In a first aspect, the present invention provides a low-temperature furnace for carbon fiber production, comprising a furnace body, two sets of connecting seats disposed on opposite inner walls of the furnace body, multiple plug-in seats, multiple double plug-in heating tubes, and a support. Each set of connecting seats includes multiple connecting seats, which are distributed along the length of the inner wall of the furnace. The multiple connecting seats in the connecting seat set correspond one-to-one with the multiple connecting seats in the opposite connecting seat set. Each connector and the side wall of the furnace body have interconnected mounting holes, and each mounting hole contains a plug-in connector. Each double-ended heating element is inserted into the sockets on opposite sides of the furnace body at its two ends. The support is set inside the furnace body and connected to the middle of the bottom wall of the furnace body. The length direction of the support is parallel to the inner wall of the furnace body where the connecting seat is set. On the side of the support away from the bottom wall of the furnace body, multiple arc-shaped grooves are opened along the length direction of the support. Each double-plug heating element consists of two short heating tubes with their ends plugged into each other, and the plug joint of the two short heating tubes is supported in an arc-shaped groove.

[0006] In an optional embodiment, the low-temperature furnace for carbon fiber production also includes two support brackets. The two support brackets are triangular prisms and are respectively arranged on opposite sides of the support brackets, splicing with the support brackets to form a trapezoidal cross-section.

[0007] In an optional implementation, the support is made of corundum mullite; Optionally, the support material is a lightweight, heat-insulating, and fire-resistant material.

[0008] In an optional embodiment, the plug-in socket is wrapped with a thermal insulation and fireproof layer, which consists of a rock wool layer, a fireproof board layer, and an aluminum silicate board layer from the inside out. Optionally, the rock wool layer is 50mm thick, the fireproof board layer is 50mm thick, and the aluminum silicate board layer is 30mm thick.

[0009] In an optional embodiment, the low-temperature furnace for carbon fiber production further includes at least one outer cover, with mounting holes penetrating through the side wall of the furnace body, and at least one outer cover covering the outer wall of the furnace body to completely cover all the mounting holes. A high-temperature resistant sealing ring is installed between the outer wall of the furnace body and the edge of the outer cover.

[0010] In an optional implementation, the high-temperature resistant sealing ring is made of fluororubber; Optionally, the outer cover is fixed to the outer wall of the furnace body with screws.

[0011] In an optional implementation, an arc-shaped buffer layer is attached to the wall of each arc-shaped groove.

[0012] In an optional implementation, the material of the arc-shaped buffer layer is aluminum silicate fiber cotton; Optionally, the thickness of the aluminum silicate fiber cotton is 2mm.

[0013] In an optional implementation, the connector is made of stainless steel with a thickness of 10mm; Optionally, each socket has a diameter of 8mm and a length of 50mm; Secondly, the present invention provides a carbon fiber production method, which is carried out using a low-temperature furnace for carbon fiber production as described in any of the foregoing embodiments.

[0014] The beneficial effects of the low-temperature furnace and production method for carbon fiber production provided in this invention include: The low-temperature furnace for carbon fiber production provided in this embodiment of the invention, through the specific arrangement of the connecting base group, plug-in base, double plug-in heating tube and support, can facilitate the disassembly and assembly of the heating tube, and can achieve axial positioning and radial limiting during installation, and the heating tube is not prone to displacement during use. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the low-temperature furnace for carbon fiber production provided in this embodiment; Figure 2 A schematic diagram of the structure of the low-temperature furnace for carbon fiber production provided in this embodiment, where the internal and external structures are visible on part of the outer wall of the hidden furnace body. Figure 3 Figure 2 Sectional view at point AA; Figure 4 for Figure 3 Enlarged view at point D; Figure 5 A top view of a structure consisting of a bracket and a bracket support joined together; Figure 6 for Figure 5 Sectional view at point BB.

[0017] Icons: 100-Low-temperature furnace for carbon fiber production; 110-Furnace body; 111-Furnace wall; 120-Connecting seat; 130-Plug-in seat; 140-Double plug-in electric heating tube; 141-Electric heating short tube; 142-Insulation and fireproof layer; 142a-Rock wool layer; 142b-Fireproof board layer; 142c-Alumina silicate board layer; 143-Pin sleeve; 144-Pin; 150-Support; 151-Arc groove; 152-Arc buffer layer; 160-Support support; 171-Mounting hole; 180-Outer cover; 191-High-temperature resistant sealing ring; 192-Screw. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0022] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0023] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0024] like Figures 1 to 3 As shown, an embodiment of the present invention provides a low-temperature furnace 100 for carbon fiber production, including a furnace body 110, two sets of connecting seats disposed on opposite inner walls of the furnace body 110, multiple plug-in seats 130, multiple double plug-in electric heating tubes 140, and a support 150. Each group of connecting seats includes multiple connecting seats 120. The multiple connecting seats 120 are distributed along the length of the inner wall of the furnace body 110. The multiple connecting seats 120 in the connecting seat group are set in a one-to-one correspondence with the multiple connecting seats 120 in the opposite connecting seat group. Each connecting seat 120 and the side wall of the furnace body 110 are provided with interconnecting mounting holes 171, and each mounting hole 171 is provided with a plug-in seat 130. Each double-ended heating element 140 has its opposite ends inserted into the plug sockets 130 on the opposite side walls of the furnace body 110. The support 150 is disposed inside the furnace body 110 and connected to the middle of the bottom wall of the furnace body 110. The length direction of the support 150 is parallel to the inner wall of the furnace body 110 where the connecting seat 120 is provided. On the side of the support 150 away from the bottom wall of the furnace body 110, a plurality of arc-shaped grooves 151 are formed along the length direction of the support 150. Each double-plug electric heating tube 140 consists of two electric heating short tubes 141 with their ends plugged into each other, and the plug joint of the two electric heating short tubes 141 is supported in an arc-shaped groove 151.

[0025] The low-temperature furnace 100 for carbon fiber production provided in this embodiment of the invention, through the design of a connecting base group, a plug-in base 130, a double plug-in heating element 140, and a support 150, enables convenient disassembly and assembly of the heating element. The specific disassembly and assembly method is as follows: During assembly, the plug-in base 130 is installed in the mounting holes 171 provided on the furnace wall 111 and the connecting base 120. Then, the end of a section of electric heating short tube 141 is inserted into the plug-in base 130. The other section of electric heating short tube 141 is inserted into the other side of the furnace wall 111 in the same manner. The two sections of electric heating short tube 141 that are respectively inserted on the furnace wall 111 are connected to each other to complete the axial positioning of the electric heating tube. The insertion position is adjusted so that it is exactly in the arc groove 151 to complete the radial limiting of the electric heating tube. During disassembly, move the two short heating tubes 141 away from each other to disconnect them. Then, simply pull the short heating tubes 141 out of the corresponding sockets 130 to complete the disassembly of the heating tubes.

[0026] Therefore, the low-temperature furnace 100 for carbon fiber production provided in this embodiment of the invention has the characteristics of easy disassembly and assembly, easy replacement of heating tubes, and easy to avoid damaging the furnace wall 111 structure during disassembly and assembly.

[0027] like Figure 4 As shown, optionally, the specific structure of each double-plug electric heating tube 140 is as follows: it includes two electric heating short tubes 141, one of which has at least two plug sleeves 143 on its end face, and the other electric heating short tube 141 has a plug 144 on its end face corresponding to the number and position of the plug sleeves. The two electric heating short tubes 141 are plugged in by inserting the plug 144 into the plug sleeves 143 one by one.

[0028] like Figure 1 , Figure 3 , Figure 5 and Figure 6 As shown, optionally, the low-temperature furnace 100 for carbon fiber production also includes two support brackets 160. The two support brackets 160 are triangular prisms and are respectively arranged on opposite sides of the support bracket 150, splicing with the support bracket 150 to form a trapezoidal cross-section.

[0029] The aforementioned support 160 configuration improves the stability of the support 150 when supporting the heating element.

[0030] Optionally, the support 150 and / or the connector 130 are made of corundum mullite. This material has good fire resistance and good strength. Preferably, the corundum mullite contains 85% Al2O3.

[0031] Optionally, the support 160 is made of lightweight thermal insulation and refractory material. Specific examples of lightweight thermal insulation and refractory material include mullite lightweight bricks; porosity 40-50%; alumina content 50%–80%; density 0.7–1.0 g / cm³.

[0032] like Figure 3 As shown, optionally, the socket 130 is wrapped with a thermal insulation and fireproof layer 142 inside the mounting hole 171. The thermal insulation and fireproof layer 142 consists of a rock wool layer 142a, a fireproof board layer 142b, and an aluminum silicate board layer 142c from the inside to the outside.

[0033] The rock wool layer fills the gaps, the fireproof board layer blocks tar, and the aluminum silicate board enhances the insulation. The specific design of the insulation and fireproof layer 142 can prevent heat loss from the furnace through the joint between the heating tube and the plug-in socket 130, thereby improving the insulation performance of the low-temperature furnace.

[0034] Optionally, the rock wool layer 142a has a thickness of 50mm, the fireproof board layer 142b has a thickness of 50mm, and the aluminum silicate board layer 142c has a thickness of 30mm.

[0035] like Figure 2 and Figure 3 As shown, optionally, the low-temperature furnace 100 for carbon fiber production also includes at least one outer cover 180, with mounting holes 171 penetrating through the side wall of the furnace body 110, and at least one outer cover 180 covering the outer wall of the furnace body 110, covering all mounting holes 171; a high-temperature resistant sealing ring 191 is provided between the outer wall of the furnace body 110 and the edge of the outer cover 180.

[0036] The high-temperature resistant sealing ring 191 and the outer cover 180 can seal the furnace body 110, preventing external gas from entering the furnace body 110 and also preventing gas leakage from the furnace body 110.

[0037] Furthermore, the number of outer covers 180 can be one or more. When there is only one outer cover 180, it covers all the mounting holes. When there are multiple outer covers, one outer cover can cover one mounting hole, or multiple mounting holes can be covered by one outer cover, such as... Figure 1 The structure shown is an outer cover that covers two mounting holes.

[0038] Optionally, the high-temperature resistant sealing ring 191 is made of fluororubber. This material can withstand temperatures up to 400°C and fits tightly against the edges of the furnace wall 111 and the outer casing 180.

[0039] like Figure 2 and Figure 3 As shown, optionally, the outer cover 180 is fixed to the outer wall of the furnace body 110 by screws 192. When installing the outer cover 180 by screws 192, the high-temperature resistant sealing ring 191 is pressed tightly against the outside of the furnace wall 111.

[0040] Optionally, an arc-shaped buffer layer 152 is attached to the wall of each arc-shaped groove 151. The arc-shaped buffer layer 152 is provided to limit the radial sway of the heating element and to prevent tar from seeping into the gaps.

[0041] Optionally, the curved buffer layer 152 is made of aluminum silicate fiber cotton. Aluminum silicate has high temperature resistance, and choosing aluminum silicate fiber cotton as the buffer layer can ensure the durability of the buffer layer.

[0042] Optionally, the aluminum silicate fiber cotton has a thickness of 2 mm. This thickness of aluminum silicate fiber cotton has a better effect on limiting the radial sway of the heating element.

[0043] Optionally, the furnace wall 111 connecting seat 120 is made of stainless steel with a thickness of 10mm. This material and thickness of the connecting seat 120 provides better strength and high-temperature resistance.

[0044] Optionally, each socket 130 has a diameter of 8 mm and a length of 50 mm.

[0045] Furthermore, the method for installing the parts involved in the low-temperature furnace 100 for carbon fiber production provided by the present invention is as follows: like Figures 1 to 3As shown, the corundum mullite support 150 is fixed inside the furnace body 110. The support 150 is adjusted to match the curvature of the heating tube, so that the length direction of the arc groove is consistent with the length direction of the heating tube. The plug-in socket 130 is installed in the mounting holes 171 on the furnace wall 111 and the connecting seat 120. The ends of the two short heating tubes 141 in the set are respectively inserted into the plug-in socket 130, and the two short heating tubes 141 are interlocked to complete the axial fixation. The plug-in socket is wrapped around the end of the heating tube. The outer periphery of the seat 130 is first wrapped with a rock wool layer 142a (50mm thick), then covered with a fireproof board layer 142b (50mm thick), and the outermost layer is fitted with a prefabricated aluminum silicate tube shell (i.e., aluminum silicate board layer, 30mm thick). A high-temperature sealing ring is installed at the location corresponding to the outer cover 180 on the outside of the furnace wall 111. The outer cover 180 is fixed to the outside of the furnace wall 111 with screws 192. At this time, the outer cover 180 presses the high-temperature sealing ring between the furnace wall 111 and the outer cover 180. The design of "axial pin + radial support 150 limiting" can achieve a displacement of ≤0.3mm for the electric heating tube, solving the problem of thermal expansion and contraction displacement. The three-layer insulation structure (rock wool layer, fireproof board layer, and aluminum silicate board layer) reduces the heat loss rate of the electric heating tube by 25%, achieves zero leakage of the high-temperature sealing ring, and the temperature fluctuation inside the furnace is ±0.8℃. The structure provided by this invention only requires pulling out the heating element and removing the bracket 150 to complete the disassembly, which reduces the traditional disassembly time of 5 hours to 20 minutes, greatly improving efficiency. This invention also isolates and blocks the corrosion path of tar, extending the maintenance cycle of the heating element to 12 months / time, and increasing its service life by at least 5 times.

[0046] This invention also provides a carbon fiber production method, which is implemented using the low-temperature furnace 100 for carbon fiber production provided by this invention.

[0047] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-temperature furnace for carbon fiber production, characterized in that, Includes a furnace body, two sets of connecting seats disposed on the two opposite inner walls of the furnace body, multiple plug-in sockets, multiple double plug-in heating tubes, and a support. Each group of connecting seats includes multiple connecting seats, which are distributed along the length of the inner wall of the furnace. The multiple connecting seats in each connecting seat group correspond one-to-one with the multiple connecting seats in the opposite connecting seat group. Each of the connecting seats and the side wall of the furnace body are provided with interconnecting mounting holes, and each of the mounting holes is provided with a plug-in seat; The two ends of each of the double-plug electric heating tubes are respectively inserted into the plug sockets on the opposite side walls of the furnace body; The support is disposed inside the furnace body and connected to the middle of the bottom wall of the furnace body. The length direction of the support is parallel to the inner wall of the furnace body where the connecting seat is disposed. On the side of the support away from the bottom wall of the furnace body, multiple arc-shaped grooves are formed along the length direction of the support. Each of the aforementioned double-plug electric heating tubes consists of two short electric heating tubes whose ends are plugged into each other, and the plug joint of the two short electric heating tubes is supported in an arc-shaped groove.

2. The low-temperature furnace for carbon fiber production according to claim 1, characterized in that, The low-temperature furnace for carbon fiber production also includes two support brackets. The two support brackets are triangular prisms and are respectively arranged on opposite sides of the support brackets, splicing with the support brackets to form a trapezoidal cross-section.

3. The low-temperature furnace for carbon fiber production according to claim 2, characterized in that, The support is made of corundum mullite; Optionally, the support is made of lightweight, heat-insulating, and fire-resistant material.

4. The low-temperature furnace for carbon fiber production according to claim 1, characterized in that, The plug-in socket is wrapped with a heat-insulating and fireproof layer, which consists of a rock wool layer, a fireproof board layer, and an aluminum silicate board layer from the inside to the outside. Optionally, the rock wool layer is 50mm thick, the fireproof board layer is 50mm thick, and the aluminum silicate board layer is 30mm thick.

5. The low-temperature furnace for carbon fiber production according to claim 1, characterized in that, The low-temperature furnace for carbon fiber production also includes at least one outer cover, the mounting holes penetrate through the side wall of the furnace body, and the at least one outer cover covers the outer wall of the furnace body, completely covering all the mounting holes; A high-temperature resistant sealing ring is provided between the outer wall of the furnace body and the edge of the outer cover.

6. The low-temperature furnace for carbon fiber production according to claim 5, characterized in that, The high-temperature resistant sealing ring is made of fluororubber. Optionally, the outer cover is fixed to the outer wall of the furnace body by screws.

7. The low-temperature furnace for carbon fiber production according to claim 1, characterized in that, Each of the arc-shaped grooves has an arc-shaped buffer layer attached to its groove wall.

8. The low-temperature furnace for carbon fiber production according to claim 7, characterized in that, The material of the arc-shaped buffer layer is aluminum silicate fiber cotton; Optionally, the thickness of the aluminum silicate fiber cotton is 2 mm.

9. The low-temperature furnace for carbon fiber production according to claim 1, characterized in that, The connector is made of stainless steel and has a thickness of 10mm. Optionally, each of the said connectors has a diameter of 8 mm and a length of 50 mm.

10. A method for producing carbon fiber, characterized in that, The process is carried out using a low-temperature furnace for carbon fiber production as described in any one of claims 1 to 9.

Images