阅读说明：本技术 基材镀膜系统 (Substrate coating system ) 是由 来华杭 俞峰 鲁天豪 娄国明 周海龙 于 2020-05-26 设计创作，主要内容包括：本申请公开了一种基材镀膜系统,包括供气机构、反应炉以及抽气机构,所述反应炉包括第一炉体,以及位于所述第一炉体内的第二炉体,所述第一炉体与所述第二炉体之间为中间腔,所述第一炉体开设有排气口,所述第二炉体具有进气口与出气口；所述供气机构通过工艺气路与所述进气口相连通；所述抽气机构通过抽气管与所述排气口相连通,所述第二炉体连接有出气管,所述出气管的一端与所述出气口相连通,另一端穿过排气口并延伸至所述抽气管,且所述出气管与所述抽气管之间呈间隙配合,该间隙开放于所述中间腔,该方案相对于现有技术,抽气机构将第二炉体内的工艺气体抽出时,能够避免工艺气体对中间腔污染。(The application discloses a substrate coating system, which comprises a gas supply mechanism, a reaction furnace and a gas exhaust mechanism, wherein the reaction furnace comprises a first furnace body and a second furnace body positioned in the first furnace body, an intermediate cavity is arranged between the first furnace body and the second furnace body, the first furnace body is provided with a gas exhaust port, and the second furnace body is provided with a gas inlet and a gas outlet; the gas supply mechanism is communicated with the gas inlet through a process gas path; the gas exhaust mechanism is communicated with the gas exhaust port through the gas exhaust pipe, the second furnace body is connected with the gas outlet pipe, one end of the gas outlet pipe is communicated with the gas outlet, the other end of the gas outlet pipe penetrates through the gas exhaust port and extends to the gas exhaust pipe, the gas outlet pipe and the gas exhaust pipe are in clearance fit, and the clearance is opened in the middle cavity.)

1. The substrate coating system comprises a gas supply mechanism, a reaction furnace and a gas exhaust mechanism, and is characterized in that,

the reaction furnace comprises a first furnace body and a second furnace body positioned in the first furnace body, an intermediate cavity is arranged between the first furnace body and the second furnace body, the first furnace body is provided with an exhaust port, and the second furnace body is provided with an air inlet and an air outlet;

the gas supply mechanism is communicated with the gas inlet through a process gas path;

the air exhaust mechanism is communicated with the exhaust port through an exhaust pipe, the second furnace body is connected with an air outlet pipe, one end of the air outlet pipe is communicated with the air outlet, the other end of the air outlet pipe penetrates through the exhaust port and extends to the exhaust pipe, the air outlet pipe and the exhaust pipe are in clearance fit, and the clearance is opened in the middle cavity.

2. The substrate coating system of claim 1, wherein the gas supply mechanism comprises a material tank and a mixing device communicated with the material tank through a pipeline, one end of the process gas path is communicated with the mixing device, and the other end of the process gas path is communicated with the gas inlet through the second furnace body.

3. The substrate coating system of claim 2, wherein the mixing device comprises a first mixing chamber and a second mixing chamber in communication with the first mixing chamber, the first mixing chamber is in communication with the feedstock tank, and the second mixing chamber is in communication with the process gas path;

the second mixing bin is provided with a temperature control device for adjusting the temperature of the second mixing bin.

4. The substrate coating system of claim 1, wherein a retainer is disposed between the outlet tube and the first furnace body, the retainer being configured to maintain a relative position between the outlet tube and the pumping tube.

5. The substrate coating system of claim 4, wherein the holder comprises:

the mounting ring is mounted on the inner wall of the first furnace body and surrounds the exhaust port;

and the fixing strips are connected between the circumferential direction of the outer wall of the air outlet pipe and the mounting ring.

6. The substrate coating system of claim 1, wherein the pumping mechanism comprises:

the cooling tank is communicated with the exhaust port through the exhaust pipe;

the filter tank is communicated with the cooling tank through a pipeline;

and the pump set is communicated with the filter tank through a process air exhaust branch.

7. The system for coating a substrate according to claim 1 or 6, wherein a heating layer is disposed outside the exhaust tube.

8. The substrate coating system of claim 6, wherein the process pumping branch comprises a main branch and a secondary branch, and the main branch and the secondary branch are respectively communicated with the pump set and the filter tank;

the main branch and/or the auxiliary branch are/is provided with a valve.

9. The system for coating a substrate according to claim 8, wherein the two ends of the secondary branch are respectively connected to the primary branch;

and the valve is arranged on the main branch and is positioned between the two joints of the auxiliary branch and the main branch.

10. The substrate coating system of claim 1, wherein the reaction furnace further comprises:

the temperature adjusting device is arranged in the middle cavity;

the object placing table is arranged in the second furnace body and used for bearing the substrate;

and the driving device is connected with the object placing table and used for driving the object placing table to lift and rotate.

Technical Field

The application relates to the field of coating equipment, in particular to a substrate coating system.

Background

The coating system comprises an air supply mechanism, a reaction furnace and an air exhaust mechanism, wherein the reaction furnace comprises a first furnace body and a second furnace body positioned in the first furnace body. When the base material is coated, the base material is placed in the second furnace body, the space between the first furnace body and the second furnace body is exhausted through the air exhaust mechanism, the first furnace body is heated to a set temperature, the process gas is conveyed into the second furnace body through the air supply mechanism, after the base material is coated, the process gas in the second furnace body needs to be completely exhausted, and after the base material is cooled, the pump is stopped, the cavity is opened, and the product is taken out.

In the coating system, the first furnace body and the second furnace body need to be exhausted by independent air exhausting mechanisms respectively, so that the coating system is complex in structure and the manufacturing cost is increased.

Disclosure of Invention

The application provides a pair of substrate coating system for it need bleed to first furnace body and second furnace body respectively to need independent bleed mechanism among the solution prior art, causes coating system structure complicacy, increases manufacturing cost's technical problem.

The application provides a substrate coating system, which comprises a gas supply mechanism, a reaction furnace and a gas exhaust mechanism;

the reaction furnace comprises a first furnace body and a second furnace body positioned in the first furnace body, an intermediate cavity is arranged between the first furnace body and the second furnace body, the first furnace body is provided with an exhaust port, and the second furnace body is provided with an air inlet and an air outlet;

the gas supply mechanism is communicated with the gas inlet through a process gas path;

the air exhaust mechanism is communicated with the exhaust port through an exhaust pipe, the second furnace body is connected with an air outlet pipe, one end of the air outlet pipe is communicated with the air outlet, the other end of the air outlet pipe penetrates through the exhaust port and extends to the exhaust pipe, the air outlet pipe and the exhaust pipe are in clearance fit, and the clearance is opened in the middle cavity.

Several alternatives are provided below, but not as an additional limitation to the above general solution, but merely as a further addition or preference, each alternative being combinable individually for the above general solution or among several alternatives without technical or logical contradictions.

Optionally, the air feed mechanism includes the head tank, and with the mixing arrangement that the head tank is linked together through the pipeline, the one end of technology gas circuit with the mixing arrangement is linked together, and the other end wears to establish the second furnace body with the air inlet is linked together.

Optionally, the mixing device includes a first mixing bin and a second mixing bin communicated with the first mixing bin, the first mixing bin is communicated with the raw material tank, and the second mixing bin is communicated with the process gas circuit;

the second mixing bin is provided with a temperature control device for adjusting the temperature of the second mixing bin.

Optionally, a retainer is arranged between the air outlet pipe and the first furnace body, and the retainer is used for maintaining the relative position between the air outlet pipe and the air exhaust pipe.

Optionally, the holder includes:

the mounting ring is mounted on the inner wall of the first furnace body and surrounds the exhaust port;

and the fixing strips are connected between the circumferential direction of the outer wall of the air outlet pipe and the mounting ring.

Optionally, the air suction mechanism includes:

the cooling tank is communicated with the exhaust port through the exhaust pipe;

the filter tank is communicated with the cooling tank through a pipeline;

and the pump set is communicated with the filter tank through a process air exhaust branch.

Optionally, a heating layer is arranged outside the exhaust pipe.

Optionally, the process air exhaust branch comprises a main branch and an auxiliary branch, and the main branch and the auxiliary branch are respectively communicated with the pump set and the filter tank;

the main branch and/or the auxiliary branch are/is provided with a valve.

Optionally, two ends of the secondary branch are respectively communicated with the primary branch;

and the valve is arranged on the main branch and is positioned between the two joints of the auxiliary branch and the main branch.

Optionally, the reaction furnace further comprises:

the temperature adjusting device is arranged in the middle cavity;

the object placing table is arranged in the second furnace body and used for bearing the substrate;

and the driving device is connected with the object placing table and used for driving the object placing table to lift and rotate.

The application provides a substrate coating system, air exhaust mechanism can extract the gas in first furnace body and the second furnace body simultaneously to simplify coating system's structure. Meanwhile, when the process gas in the second furnace body is pumped out, the pollution of the process gas to the middle cavity can be avoided.

Drawings

FIG. 1 is a schematic view of a substrate coating system according to one embodiment of the present disclosure;

FIG. 2 is a schematic view of a substrate coating system according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of the gas supply mechanism of FIG. 1;

FIG. 4 is a schematic view of the suction mechanism of FIG. 1;

FIG. 5 is a schematic view of the structure of the reaction furnace of FIG. 1;

FIG. 6 is a schematic structural view of the reactor of FIG. 5 without the first cover plate;

FIG. 7 is a schematic structural view of the reactor of FIG. 5 without the first cover plate;

FIG. 8 is a schematic structural view of the reactor of FIG. 6 without a second cover plate;

FIG. 9 is a schematic structural view of the reactor of FIG. 8 without a gas distribution plate;

FIG. 10 is an enlarged view of portion A of FIG. 9;

fig. 11 is a schematic structural diagram of the driving device in fig. 9.

The reference numerals in the figures are illustrated as follows:

100. a substrate coating system;

10. a reaction furnace; 11. a first furnace body; 111. a first cylinder; 112. a first cover plate; 113. an exhaust port; 114. a guide rail; 115. a vertical axis; 116. buckling; 12. a second furnace body; 122. an air outlet; 123. a second cylinder; 124. a second cover plate; 125. a gas distribution plate; 126. an air outlet pipe; 127. a holder; 1271. a mounting ring; 1272. a fixing strip; 128. a pulley; 15. a placing table; 16. a drive device; 161. a first motor; 162. a rotating drum; 163. a second motor; 164. a push rod; 165. a chassis; 166. a guide bar; 167. spokes; 168. a gear set; 1681. a wheel carrier; 1682. a driving gear; 1683. a driven gear;

20. an air supply mechanism; 21. a process gas circuit; 22. a raw material tank; 23. a mixing device; 231. a first mixing bin; 232. a second mixing bin;

30. an air extraction mechanism; 31. an air exhaust pipe; 32. a cooling tank; 33. a filter tank; 34. a process air exhaust branch; 341. a main branch; 342. a secondary branch; 343. a valve; 35. and a pump group.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In one embodiment, as shown in fig. 1 to 11, the present application provides a substrate coating system 100 for depositing a silicon carbide film on a graphite substrate, the substrate coating system 100 includes a gas supply mechanism 20, a reaction furnace 10 and a gas exhaust mechanism 30;

the reaction furnace 10 includes a first furnace body 11 and a second furnace body 12 located in the first furnace body 11, an intermediate cavity is formed between the first furnace body 11 and the second furnace body 12, and the second furnace body 12 has an air inlet and an air outlet 122.

The air supply mechanism 20 is communicated with the air inlet through the process air path 21, and the air exhaust mechanism 30 is communicated with the air outlet 122 through the air exhaust pipe 31.

Further, the first furnace body 11 is provided with an exhaust port 113, the air exhaust mechanism 30 is communicated with the exhaust port 113 through an exhaust pipe 31, the second furnace body 12 is connected with an air outlet pipe 126, one end of the air outlet pipe 126 is communicated with the air outlet 122, the other end of the air outlet pipe 126 penetrates through the exhaust port 113 and extends to the exhaust pipe 31, the air outlet pipe 126 and the exhaust pipe 31 are in clearance fit, and the clearance is opened in the middle cavity.

The air-extracting mechanism 30 can extract the air in the first furnace body 11 and the second furnace body 12 at the same time, so as to simplify the structure of the coating system 100. Meanwhile, when the process gas in the second furnace body 12 is pumped out, the pollution of the process gas to the middle cavity can be avoided.

The substrate is placed in the second furnace body 12, the middle cavity is pumped through the air pumping mechanism 30, the first furnace body 11 is heated to a set temperature, the process gas is conveyed into the second furnace body 12 through the air supply mechanism 20, after the substrate coating is finished, the process gas is completely discharged through air pumping circulation for several times, and after cooling, the pump is stopped, the cavity is opened, and a product is taken out.

The middle cavity is a vacuum cavity, and the vacuum cavity can be vacuum or close to vacuum, so that the middle cavity is not easy to pollute, and heat is not easy to quickly dissipate.

In another embodiment, as shown in fig. 9 and 10, a retainer 127 is disposed between the outlet tube 126 and the exhaust tube 31, and the retainer 127 is used to maintain the relative position between the outlet tube and the exhaust tube 31.

Preferably, the cage 127 comprises:

a mounting ring 1271 mounted on the inner wall of the first furnace body 11 and surrounding the exhaust port 113;

and a plurality of fixing strips 1272 connected between the outer wall of the air outlet pipe 126 and the mounting ring 1271 in the circumferential direction.

In another embodiment, as shown in fig. 3, the gas supply mechanism 20 includes a material tank 22, and a mixing device 23 connected to the material tank 22 through a pipeline, one end of the process gas path 21 is connected to the mixing device 23, and the other end thereof penetrates through the second furnace body 12 and is connected to the gas inlet. The first furnace body 11 is provided with a joint for communicating the process gas path 21 with the gas inlet, the raw material tank 22 is used for storing process gas, the bottom of the raw material tank 22 conveys the process gas into the mixing device 23 through a pipeline for mixing, and then the process gas is conveyed into the second furnace body 12 through the process gas path 21 to perform a process reaction with the substrate.

In another embodiment, the mixing device 23 includes a first mixing bin 231 and a second mixing bin 232 communicated with the first mixing bin 231, the first mixing bin 231 is communicated with the raw material tank 22, and the second mixing bin 232 is communicated with the process gas circuit 21.

Head tank 22, first mixed storehouse 231 and second mix storehouse 232 and set up for the components of a whole that can function independently, can place and quantity according to the nimble adjustment of place and customer's demand, satisfy different technology demands. The process gases are mixed in the first mixing bin 231 and then mixed in the second mixing bin 232. The mixing by the first mixing silo 231 reduces the equipment investment and reaction time for preparing the process gas.

Further, the second mixing bin 232 is provided with a temperature control device for adjusting the temperature of the second mixing bin 232. The temperature control device wraps the outer side wall of the second mixing bin 232 and electrically heats the second mixing bin 232.

The process gas is liquid at normal temperature, so that the process gas is required to be heated to be in a gas state, the temperature control device can heat the second mixing bin 232, the process gas can be effectively protected from being liquefied at the normal temperature, the process gas has a storage function, and temperature control from-5 ℃ to 100 ℃ can be realized by matching with a constant temperature machine, so that the process gas is suitable for gases under different processes.

In another embodiment, as shown in FIG. 4, the suction mechanism 30 includes:

a cooling tank 32, wherein the cooling tank 32 is communicated with the exhaust port 113 through an exhaust pipe 31;

a filter tank 33, the filter tank 33 is communicated with the cooling tank 32 through a pipeline;

a pump set 35 in communication with the canister 33 through a process pump down branch 34.

The process gas reacts in the second furnace body 12 to generate chlorosilane, the chlorosilane reacts with water to generate solid particles to destroy the pump unit 35, so that the chlorosilane can be liquefied after being cooled to 60 ℃ according to the physical characteristics of the chlorosilane, and the chlorosilane component in the gas is cooled in the cooling tank 32 to avoid the damage to the pump caused by the chlorosilane component entering the pump unit 35.

The filter tank 33 is used for filtering micro-particle substances, protecting the pump unit 35 and avoiding the occurrence of the situation that the pump unit 35 is blocked due to accumulation of particles.

The pump unit 35 comprises a first-stage pump, a second-stage pump and a third-stage pump, wherein the first-stage pump is a liquid ring pump, the second-stage pump is a gas-cooled roots pump, the third-stage pump is a roots pump, and an anti-corrosion coating needs to be plated in the pump unit 35 due to the fact that hydrogen and corrosive gas exist in tail gas, and liquid in a gas-liquid separation barrel of the liquid ring pump is subjected to acid-base balance, so that corrosion of the liquid ring pump is reduced. The second-stage pump adopts air-cooled roots, so that the pressure difference between the first-stage pump and the third-stage pump can be increased, and the condition that the common roots pump is overheated due to large pressure difference is avoided. Meanwhile, in some special processes, only the first-stage pump and the second-stage pump are needed to be started, and a third-stage pump is not needed to be started, so that the processes are not explained.

In another embodiment, in order to prevent the exhaust gas entering the exhaust pipe 31 from changing, a heating layer is disposed outside the exhaust pipe 31.

In another embodiment, the process pumping branch 34 comprises a main branch 341 and a sub-branch 342, and the main branch 341 and the sub-branch 342 are respectively communicated with the pump set 35 and the filter tank 33;

the primary branch 341 and/or the secondary branch 342 are provided with a valve 343.

When the substrate is coated, the air suction amount is not required to be so much, and at this time, the air amount is adjusted by adjusting the valve 343 (closing the main branch 341 or the sub-branch 342, or adjusting the flow rate of the main branch 341 or the sub-branch 342), so that the air suction amount under different processes is adapted.

Further, in order to simplify the structure of the process pumping branch 34, two ends of the secondary branch 342 are respectively communicated with the primary branch 341;

the valve 343 is disposed on the main branch 341 and is located between two junctions of the sub-branch 342 and the main branch 341.

In another embodiment, as shown in fig. 5 to 11, a placing table 15 disposed in the second furnace body 12 for supporting the substrate, a temperature adjusting device disposed in the intermediate chamber, and a driving device 16 connected to the placing table 15 for driving the placing table 15 to move up and down and rotate.

The reaction furnace 10 is designed by adopting a conventional horizontal type circular cavity conventional pressure container, can work in positive pressure and negative pressure environments, can meet the requirements of various processes, reduces the manufacturing cost and is convenient to maintain. The object placing table 15 can realize all-dimensional covering of the substrate coating through rotation, so that the coating is uniform, and meanwhile, the object placing table 15 can lift to ensure uniform covering of the substrate in the vertical direction.

In another embodiment, the first furnace body 11 includes a first cylinder 111 and two first cover plates 112 respectively fastened to two ends of the first cylinder 111, and the second furnace body 12 can enter the first furnace body 11 through one end of the first cylinder 111.

Each first cover plate 112 is hinged to the first cylinder 111 through a vertical shaft 115, and each first cover plate 112 can be fixed to the first cylinder 111 through a buckle 116. The end surface of each first cover plate 112 is attached to the end surface of the corresponding end of the first cylinder 111, so that the space in the first furnace 11 is sealed.

In another embodiment, the second furnace body 12 includes a second cylinder 123 and two second cover plates 124 respectively fastened to two ends of the second cylinder 123, one of the two second cover plates 124 is provided with an air inlet, and the other is provided with an air outlet 122.

Each second cover plate 124 is detachably fixed to the second cylinder 123 through bolts, and an end surface of each second cover plate 124 is attached to an end surface of a corresponding end of the second cylinder 123, so that the space in the second furnace body 12 is sealed.

In another embodiment, in order to make the process gas entering the second furnace body 12 flow uniformly, at least two gas distribution disks 125 are further provided in the second furnace body 12, and the periphery of each gas distribution disk 125 is connected with the inner wall of the second furnace body 12 and is respectively arranged opposite to the two second cover plates 124.

In order to facilitate the installation of the gas distribution plate 125 in the second furnace body 12, a hem is provided at the periphery of each gas distribution plate 125, and the hem is attached to the inner wall of the second furnace body 12.

In the present embodiment, the number of the air distribution disks 125 is two, wherein one air distribution disk 125 is disposed opposite to the second cover plate 124 provided with the air inlet, and the other air distribution disk 125 is disposed opposite to the second cover plate 124 provided with the air outlet 122. Of course, in other embodiments, the number of the air distribution plates 125 can be adjusted according to actual needs, and is not illustrated here.

In another embodiment, the driving device 16 includes a first motor 161 installed on an outer sidewall of the first furnace body 11, a drum 162 linked with the motor, a second motor 163 installed on the drum 162, and a push rod 164 located inside the drum 162;

the drum 162 sequentially passes through the first furnace body 11 and the second furnace body 12; the push rod 164 rotates with the drum 162 and is driven by the second motor 163 to move along the axial direction of the drum 162, and the push rod 164 is connected with the object placing table 15.

Specifically, the first motor 161 is linked with the drum 162 through a gear set 168, the gear set 168 includes a wheel carrier 1681, a driving gear 1682 and a driven gear 1683 installed in the wheel carrier 1681, the wheel carrier 1681 is installed on the outer side wall of the first furnace body 11, the drum 162 is rotatably installed on the wheel carrier 1681 and extends into the wheel carrier 1681 to be coaxial with the driven gear 1683, an output shaft of the first motor 161 is connected with the driving gear 1682, and the driving gear 1682 is directly or indirectly engaged with the driven gear 1683; the second motor 163 is fixed to the wheel frame 1681, and an output shaft of the second motor 163 is connected to the push rod 164. Wherein the second motor 163 is a push rod 164 motor.

In another embodiment, the driving device 16 further includes a base plate 165 and a guide rod 166, the base plate 165 is fixedly connected to the top end of the drum 162, and the base plate 165 is circumferentially provided with a guide sleeve; one end of the guide rod 166 is connected with the top end of the push rod 164, the other end of the guide rod 166 extends out of the guide sleeve to be connected with the bottom of the object placing table 15, and the guide rod 166 can slide along the guide sleeve; the push rod 164 is linked to the stand 15 by a guide rod 166.

Wherein, the chassis 165 is fixedly connected with the top of the drum 162 by welding or bolts. In order to stabilize the movement of the object placing table 15, the number of the guide rods 166 is at least three, and the guide rods are uniformly distributed at intervals in the circumferential direction of the base plate 165. Of course, in other embodiments, the number of the guide rods 166 can be set according to actual needs, and will not be further described herein.

The guide sleeve has a guide hole that mates with the guide rod 166. In this embodiment, the guide sleeve is provided integrally with the chassis 165. Of course, in other embodiments, the guide sleeve may be provided separately from the chassis 165.

In another embodiment, the guide sleeve is radially outside the drum 162;

the driving device 16 further includes a spoke 167, the spoke 167 is fixed on the top end of the push rod 164 and extends to the outer side of the rotating drum 162 along the radial direction of the push rod 164, the bottom end of the guide rod 166 is fixed on the spoke 167, and an avoiding opening avoiding the spoke 167 is opened on the side wall of the rotating drum 162.

The spokes 167 are fixed to the push rod 164 by bolts, welding, or the like, and the spokes 167 have a width so that the spokes 167 have a certain supporting strength.

In another embodiment, the temperature adjusting device includes a cooling member, a heating member and an insulating layer, the cooling member is disposed on the inner sidewall of the first furnace body 11 and used for cooling the intermediate chamber; the heating element is arranged on the outer side wall of the second furnace body 12 and is used for heating the second furnace body 12; the heat preservation parcel second furnace body 12's lateral wall, the heating member is located between heat preservation and the second furnace body 12.

A cooling interlayer is arranged in the first furnace body 11, and a cooling piece is arranged in the cooling interlayer. The cooling piece is the cooling tube, and the cooling tube leads to the pump and is linked together with outside water source, and the pump carries condenser tube with the cooling water of outside water source, can lower the temperature to the middle chamber.

The second furnace body 12 is provided with a heating interlayer, and the heating element is arranged in the heating interlayer. The number of the heating members is plural, and each heating member extends along the axis of the second cylinder 123 and is uniformly spaced around the outer side wall of the second furnace body 12.

Because of the higher certain heat preservation, leakproofness and the heat resistance of temperature needs during the coating film, the setting up of heat preservation can avoid the high temperature that the heating member produced to melt outside metal, can also prevent the heat loss simultaneously.

In another embodiment, in order to facilitate the second furnace body 12 to enter the first furnace body 11, one of the inner wall of the first furnace body 11 and the outer wall of the second furnace body 12 is provided with a guide rail 114, and the other is provided with a pulley 128 engaged with the guide rail 114.

In the present embodiment, the guide rails 114 are provided on the inner wall of the first furnace body 11, and the pulleys 128 are provided on the outer wall of the second furnace body 12.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features. When technical features in different embodiments are represented in the same drawing, it can be seen that the drawing also discloses a combination of the embodiments concerned.

The above examples only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application.