Gas Heated Deposition Furnace and System

Abstract

The present invention discloses a gas-heated deposition furnace and system, including a furnace body and a heating device for heating an object to be densified in the furnace body, wherein an air outlet penetrating into the inner cavity of the furnace body is arranged at the upper part of the furnace body, and the heating device includes at least one radiation tube extending into the furnace body for heat dissipation and a burner for heating the radiation tube by burning the tail gas in the air outlet pipe. The heating method of the deposition furnace is changed to a gas-heated radiation tube form, and the fuel is mainly the tail gas of the deposition furnace and supplemented by natural gas, which not only saves a lot of electric energy, but also uses the tail gas of the deposition furnace as a heat source to heat the deposition furnace, and at the same time, the combustion flue gas from the gas-heated radiation tube preheats the carbon source gas, truly achieving energy saving and environmental protection of the deposition furnace system.

Description

Technical Field

[0001] The invention relates to the field of chemical vapor deposition preparation, and in particular to a gas-heated deposition furnace and a system. Background Art

[0002] With the rapid development of electronics, semiconductors, solar energy and aerospace technology, the demand for C / C composite materials with excellent high temperature resistance and thermal shock resistance has also increased rapidly. C / C composite materials are products that have been graphitized and enhanced on the basis of carbon fibers, and the gas-heated deposition furnace (CVI) is the core equipment for manufacturing high-performance carbon-carbon composite materials. However, the existing deposition furnaces on the market are not very perfect, mainly manifested in: the uneven temperature distribution in the furnace leads to low and uneven deposition rate, the calorific value of the waste gas after the carbon source gas passes through the deposition furnace is very high, and the waste gas must be incinerated for environmental reasons. The heat recovery efficiency of the waste gas incineration is low, and the heat source of the deposition furnace still uses electric heating, which consumes a lot of electricity, which not only increases the equipment cost (electric heating requires a large transformer), but also increases the carbon emissions of the system production. Summary of the invention

[0003] The purpose of the present invention is to provide a gas-heated deposition furnace and system, in which the heating method of the deposition furnace is changed to a gas-heated radiation tube form, and the fuel is mainly the tail gas of the deposition furnace, supplemented by natural gas. This not only saves a lot of electric energy, but also uses the tail gas of the deposition furnace as a heat source to heat the deposition furnace. At the same time, the combustion flue gas coming out of the gas-heated radiation tube preheats the carbon source gas, truly achieving energy saving and environmental protection of the deposition furnace system.

[0004] A gas-heated deposition furnace comprises a furnace body and a heating device for heating the object to be densified in the furnace body, wherein the heating device comprises at least one radiation tube extending into the furnace body for heat dissipation and a burner for heating the radiation tube by burning the exhaust gas in the exhaust pipe.

[0005] Furthermore, one end of the radiation tube is a closed end placed in the inner cavity of the furnace body, and the other end is an open end penetrating the furnace body; the burner is a burner connected to the open end, and the burner extends into the radiation tube through the open end.

[0006] Furthermore, the burner includes an inner gas tube, an outer air tube sleeved outside the inner gas tube, and a burner channel. The inner gas tube is used to communicate with the air outlet pipe, and the burner channel is respectively connected with the air outlet of the outer air tube and the inner gas tube and extends into the radiation tube.

[0007] Furthermore, the burner channel includes a columnar portion, one end of which is connected to the air outer pipe, and the other end of which is a conical protrusion forming a conical portion for mixing fuel gas and air.

[0008] Furthermore, a smoke pipe is installed between the outer air pipe and the open end, a smoke outlet is arranged on the smoke pipe, and the outer air pipe is connected to the top of the smoke pipe, and the bottom of the smoke pipe and the open end are connected via flanges respectively.

[0009] Furthermore, a sleeve is provided in the radiation tube, a through combustion channel is formed in the sleeve, and the combustion channel is connected with the burner channel.

[0010] Furthermore, a first annular gap is formed between the smoke pipe and the columnar portion, a second annular gap is formed between the radiation tube and the sleeve, and the first annular gap is communicated with the second annular gap.

[0011] A gas-heated deposition furnace system includes a gas-heated deposition furnace, an exhaust gas circulation pipe, and an exhaust gas purification device arranged on the exhaust gas circulation pipe. One end of the exhaust gas circulation pipe is connected to the gas outlet of the furnace body, and the other end is connected to the gas inlet of the gas inner pipe. The exhaust gas is used to recycle the exhaust gas after the chemical vapor deposition reaction in the furnace body. The exhaust gas purification device includes a first-level exhaust gas purification device for removing corrosive gases and cooling in the exhaust gas; and a second-level exhaust gas purification device for removing dust and oil mist in the exhaust gas.

[0012] Furthermore, it also includes a flue gas preheating pipe and a preheating device arranged on the flue gas preheating pipe, which is used to preheat the chemical gas that will enter the furnace body. One end of the preheating device is connected to the flue gas outlet of the flue gas pipe, and the other end is used for flue gas discharge.

[0013] Furthermore, the exhaust gas circulation pipe is also connected to a fuel gas supply pipe, and an exhaust gas shut-off valve is provided on the exhaust gas circulation pipe to control the on-off of the exhaust gas purified by the exhaust gas purification device after the chemical vapor deposition reaction. The fuel gas supply pipe is provided with a fuel gas shut-off valve to control the on-off of the fuel gas.

[0014] The present invention has the beneficial effects:

[0015] The gas-heated deposition furnace and system of the present invention is a closed-cycle reaction system, which has an exhaust gas purification device and a preheating device. The on-off of the circulating exhaust gas is controlled by adjusting the exhaust gas cut-off valve of the exhaust gas purification device. When the circulating exhaust gas is insufficient, the low-pressure gas switch on the exhaust gas circulation pipe is actuated, and the flow rate and proportion of the added fresh gas are controlled by adjusting the on-off of the natural gas by adjusting the gas cut-off valve provided on the gas supply pipe. By using the exhaust gas discharged from the deposition furnace as heating fuel gas, electric energy is saved, the utilization rate of the exhaust gas is improved, and the problem of exhaust gas emission is solved at the same time.

[0016] 2. Replace the original electric heating device with gas radiation tube heating, use the exhaust gas discharged from the deposition furnace as one of the gas sources, mix with air, and then realize chemical vapor deposition reaction on the object to be densified in the deposition furnace. When the gas and air are heated in the combustion channel of the gas radiation tube, the combustion exhaust gas dissipates part of the heat through its surface, and the high-temperature flue gas is discharged from the annular gap between the gas radiation tube and the burner (in the process of flowing through the annular gap, the high-temperature flue gas transfers part of the heat to the combustion air of the radiation tube burner through the radiation tube burner, the temperature of the high-temperature exhaust gas decreases, and the temperature of the combustion air of the burner increases, thereby And realize the self-preheating of the burner combustion air, realize the first waste heat recovery of the combustion exhaust gas), and form the combustion exhaust gas of the radiation tube system; at the same time, in this system, a carbon source gas preheater is configured for each deposition furnace, and all the high-temperature exhaust gases of the radiation tubes of a single deposition furnace are collected together, and then introduced into the carbon source gas preheater, most of the heat is transferred to the carbon source gas, and the self-temperature is reduced and then discharged into the atmosphere through the chimney. The carbon source gas required by the deposition furnace is heated after passing through the carbon source gas preheater, and then introduced into the deposition furnace. The carbon source gas is preheated and then introduced into the deposition furnace, which effectively increases the temperature of the bottom of the deposition furnace and promotes the uniformity of the temperature at the bottom of the deposition furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the prior art structure of the present invention;

[0018] Figure 2 It is a schematic diagram of the structure of the gas-fired heating deposition furnace system of the present invention;

[0019] Figure 3 It is a schematic diagram of the enlarged structure of the burner part of the present invention;

[0020] Figure numerals: 1-furnace body, 2-electric heating component, 3-carbon fiber radiation cover, 4-support plate, 5-object to be carburized, 6-deposition furnace cover, 7-process waste gas discharge port, 8-tar condenser, 9-filter, 10-first pump, 11-waste gas incinerator, 12-heat recovery device, 13-chimney, 14-carbon source gas uniformity plate, 15-gas collecting device, 16-oil outlet, 17-second pump, 18-tail gas Shut-off valve, 19-gas shut-off valve, 20-gas low-pressure switch, 21-gas pipeline system before burner, 22-burner, 23-combustion-supporting air pipeline system before burner, 24-preheating device, 25-radiant tube, 26-combustion-supporting fan, 221-gas inner tube, 222-air outer tube, 223-smoke pipe, 224-burner channel, 224a-columnar part, 224b-conical part, 27-sleeve. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0022] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inside", "outside", "front", "back", "top", "bottom" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0023] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed", "opened", "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] Example 1

[0025] A gas-heated deposition furnace comprises a furnace body 1 and a heating device for heating the object to be densified in the furnace body 1. The upper part of the furnace body 1 is provided with an outlet penetrating into the inner cavity of the furnace body 1. The heating device comprises at least one radiation tube 25 extending into the interior of the furnace body 1 for heat dissipation and a burner for heating the radiation tube 25 by burning the exhaust gas in the outlet pipe.

[0026] In one embodiment, one end of the radiation tube 25 is a closed end placed in the inner cavity of the furnace body 1, and the other end is an open end penetrating the furnace body 1; the burner is a burner 22 connected to the open end, and the burner 22 extends into the radiation tube 25 through the open end.

[0027] Specifically, the burner 22 includes an inner gas tube 221, an outer air tube 222 sleeved outside the inner gas tube 221, and a burner channel 224. The inner gas tube 221 is used to communicate with the air outlet pipe, and the burner channel 224 is respectively connected to the air outlet of the outer air tube 222 and the inner gas tube 221 and extends into the radiation tube 25.

[0028] Specifically, the burner channel 224 includes a columnar portion 224a, one end of which is connected to the air outer tube 222, and the other end of which is a conical protrusion formed with a conical portion 224b for mixing gas and air.

[0029] Specifically, a nozzle is provided on the end of the inner gas tube 221 located inside the outer air tube 222 .

[0030] Specifically, the central axes of the outer air tube 222 , the inner gas tube 221 , and the burner channel 224 coincide with each other.

[0031] In one embodiment, a sleeve 27 is disposed in the radiation tube 25 , and a through combustion channel is formed in the sleeve 27 , and the combustion channel is connected to the burner channel 224 .

[0032] In one embodiment, the sleeve 27 is provided with at least one connector, and a reduced diameter section is provided at the lower portion of the connector.

[0033] Specifically, the sleeve 27 is a ceramic flame-resistant sleeve 27 .

[0034] In one embodiment, a smoke pipe 223 is installed between the outer air pipe 222 and the open end, and a smoke outlet is provided on the smoke pipe 223. The outer air pipe 222 and the top of the smoke pipe 223, and the bottom of the smoke pipe 223 and the open end are connected by flanges respectively.

[0035] Specifically, a first annular gap is formed between the smoke pipe 223 and the columnar portion 224 a , and a second annular gap is formed between the radiation tube 25 and the sleeve 27 , and the first annular gap is communicated with the second annular gap.

[0036] Specifically, a first connecting flange is disposed at the bottom of the outer air pipe 222, and an upper connecting flange is disposed at the top of the smoke pipe 223. The outer air pipe 222 and the smoke pipe 223 are connected via the first connecting flange and the upper connecting flange.

[0037] Specifically, a lower connecting flange is provided at the bottom of the flue gas pipe 223, and a second connecting flange is provided at the open end. The flue gas pipe 223 and the open end are connected via the lower connecting flange and the second sleeve 27 connecting flange.

[0038] The working process of the gas-heated deposition furnace is as follows: when the tail gas in the deposition furnace enters the heating device, the heating device includes a radiation tube 25 and a burner 22, and the burner 22 includes a burner channel 224, a gas inner tube 221, an air outer tube 222, and a smoke exhaust pipe. The tail gas enters the burner channel 224 through the gas inner tube 221, and the combustion-supporting gas (air) enters the burner channel 224 through the air outer tube 222; in the burner channel 224, the gas and the combustion-supporting gas undergo a combustion chemical reaction, and the smoke generated by the combustion enters the combustion channel of the inner sleeve 27 of the radiation tube 25 from the burner channel 224 outlet. The flue gas exchanges heat with the sleeve 27. One end of the sleeve 27 is connected to the burner 22, so that the fuel gas burns in the sleeve 27. The flue gas after combustion is discharged from the other end of the tube, and enters the second annular gap formed between the inner wall of the flue pipe 223 and the columnar portion 224a through the first annular gap between the outer wall of the sleeve 27 and the inner wall of the radiation tube 25, and preheats the air in the columnar portion 224a. The flue gas flows out through the flue gas outlet of the flue pipe 223 and enters the flue gas preheating pipe, flows through the preheating device 24, and preheats the carbon source gas in the preheating device 24. The preheating device 24 is an existing heat conduction device, such as a heat conduction pipe, the upper end of one side surface of the pipe is fixedly connected to the first outlet, and the lower end of the other side surface of the pipe is fixedly connected to the second outlet, the upper end of the pipe is fixedly connected to the upper connecting pipe, and the lower end of the pipe is fixedly connected to the lower connecting pipe, and the inner condensing pipe connected to the upper connecting pipe and the lower connecting pipe is arranged inside the outer condensing pipe. The upper connecting pipe, the lower connecting pipe and the inner condensing pipe are used to transmit the carbon source gas, and the flue gas is transmitted in the pipe to realize heat transfer.

[0039] Example 2

[0040] A gas-heated deposition furnace system includes a gas-heated deposition furnace, an exhaust gas circulation pipe, and an exhaust gas purification device arranged on the exhaust gas circulation pipe. One end of the exhaust gas circulation pipe is connected to the air outlet of the furnace body 1, and the other end is connected to the air inlet of the gas inner pipe 221, which is used to recycle the exhaust gas after the chemical vapor deposition reaction in the furnace body 1.

[0041] Specifically, it also includes a flue gas preheating pipe and a preheating device 24 arranged on the flue gas preheating pipe, which is used to preheat the chemical gas that will enter the furnace body 1. One end of the preheating device 24 is connected to the outlet of the flue gas pipe 223, and the other end is used for flue gas discharge.

[0042] Specifically, the exhaust gas circulation pipe is also connected to a fuel gas supply pipe, and an exhaust gas shut-off valve 18 is provided on the exhaust gas circulation pipe to control the on-off of the exhaust gas purified by the exhaust gas purification device after the chemical vapor deposition reaction. The fuel gas supply pipe is provided with a fuel gas shut-off valve 19 to control the on-off of the fuel gas.

[0043] Specifically, the exhaust gas purification equipment includes a primary exhaust gas purification equipment for removing corrosive gases and cooling the exhaust gas; and a secondary exhaust gas purification equipment for removing dust and oil mist in the exhaust gas.

[0044] In the prior art, the deposition furnace system mainly includes a furnace body 1, an electric heating component 2, a carbon fiber radiation cover 3, a furnace cover, and a carbon source gas uniformity plate. After the object 5 to be carburized (such as a crucible) is placed on a bracket, it is regularly stacked above the carbon source gas uniformity plate in the furnace. After the carbon source gas enters the furnace, it is pyrolyzed at high temperature and deposited inside the carbon fiber, filling the gaps in the object 5 to be carburized, thereby forming a high-performance carbon-carbon composite material. After the carbon source gas deposits part of the carbon on the object 5 to be carburized through a chemical reaction in the furnace, the remaining tail gas (with a more complex composition, such as H2, N2, tar and some related hydrocarbon substances) is extracted by the first pump 10 through the process waste gas discharge port 7 on the furnace cover. After the tail gas in the deposition furnace is discharged from the process waste gas discharge port 7, it is first cooled by the tar condenser 8 and then enters the first pump 10 through the filter 9 for discharge.

[0045] Since the remaining exhaust gas extracted from the first pump 10 contains H2, tar and some hydrocarbon greenhouse gases, direct discharge will cause environmental pollution and requires environmental protection treatment. For the conventional heating process of deposition furnaces currently prevalent on the market, the treatment of the remaining exhaust gas is basically carried out by high-temperature incineration: the remaining exhaust gas is used as fuel to be incinerated at high temperature in the exhaust gas incinerator 11, and the high-temperature exhaust gas after incineration is discharged into the chimney 13 after passing through the heat recovery device 12. However, it is difficult for relevant manufacturers to find a suitable way to utilize the heat recovered by the heat recovery device 12.

[0046] The deposition furnace heating process of the present invention changes the heat recovery method of the residual tail gas while ensuring that the main process remains basically unchanged, as follows:

[0047] The first pump 10 extracts the remaining tail gas from all deposition furnaces in the workshop and cools it in turn through the tar condenser 8, filters it through the filter 9, and then enters the first pump 10 to be discharged into the collection device, and then passes through the degreasing device to remove most of the liquid grease (such as tar), and then passes through the second pump 17 to pressurize the remaining tail gas after degreasing to a suitable pressure (the pressure value is determined according to the gas pressure required by the subsequent radiation tube 25 burner 22 system), passes through the tail gas shut-off valve 18, and enters the pre-burner gas pipeline system 21 (the gas pipeline system is used to adjust / stabilize the pressure, safely shut off, and adjust the flow of the gas before the burner 22), and then enters the burner 22. The combustion-supporting fan 26 draws a certain amount of fresh air from the atmosphere and pressurizes it, and then passes through the combustion-supporting air pipeline system 23 before the burner (used to adjust the air flow entering the burner 22) and also enters the air outer pipe 222 of the burner 22. The remaining exhaust gas and combustion-supporting air are mixed and ignited in the burner 22, and burn in the linear radiation tube 25, which heats the radiation tube 25 and dissipates a large part of the heat through its surface in the form of radiation heating. The linear radiation tube 25 is installed in the space where the original electric heating device of the deposition furnace is located, so that the heat dissipated from the surface of the radiation tube 25 is equivalent to the heat provided by the original electric heating. After the combustion exhaust gas in the radiation tube 25 dissipates part of the heat through its surface, the high-temperature flue gas is discharged from the annular gap between the radiation tube 25 and the burner 22 (in the process of flowing through the annular gap, the high-temperature flue gas transfers part of the heat to the combustion air of the burner 22 of the radiation tube 25 through the burner 22 of the radiation tube 25, the temperature of the high-temperature exhaust gas is reduced, and the temperature of the combustion air of the burner 22 is increased, thereby realizing the self-preheating of the combustion air of the burner 22 and realizing the first waste heat recovery of the combustion exhaust gas), forming the combustion exhaust gas of the radiation tube 25; at the same time, in this system, a carbon source is configured for each deposition furnace The gas preheating device 24 collects the high-temperature exhaust gases from all the radiation tubes 25 of a single deposition furnace together, and then passes them into the carbon source gas preheating device 24, transferring most of the heat therein to the carbon source gas, which is discharged into the atmosphere through the chimney 13 after its own temperature is reduced. The carbon source gas required by the deposition furnace is heated up after passing through the carbon source gas preheating device 24, and then passed into the deposition furnace. The carbon source gas is preheated before being passed into the deposition furnace, which effectively increases the temperature at the bottom of the deposition furnace. This not only effectively reduces the amount of tar generated by the carbon source gas in the deposition furnace, but also makes the temperature in the deposition furnace more uniform, thereby improving the uniformity of carbon deposition on the surface of the object 5 to be carburized.

[0048] During the heating stage of the deposition furnace, since no deposition exhaust gas is generated, the fuel of the burner 22 is replaced by pure natural gas. The specific method is: the exhaust gas shut-off valve 18 is placed in a closed state, and the gas shut-off valve 19 is opened. The burner 22 burns a certain amount of natural gas to increase the furnace temperature of the deposition furnace to the deposition process temperature. When the deposition exhaust gas is generated, the exhaust gas shut-off valve 18 is opened, and then the gas shut-off valve 19 is slowly closed until it is completely cut off. If during the process operation, the deposition exhaust gas pressure is insufficient, resulting in the operation of the gas low-pressure switch 20 or the heat of the deposition exhaust gas cannot meet the heat demand of the deposition furnace, the gas shut-off valve 19 can be opened to appropriately add a certain amount of natural gas to the deposition exhaust gas.

[0049] Figure 1 FIG. 1 is a schematic diagram of a gas-fired heating deposition system according to an embodiment of the present invention. Figure 1 As shown, the gas-heated deposition system provided in the embodiment of the present invention includes a furnace body 1 of a gas-heated deposition furnace.

[0050] It should be noted that the embodiment of the present invention does not impose any specific restrictions on the furnace body 1 of the deposition furnace, as long as chemical vapor deposition can be achieved. A common deposition furnace mainly includes a furnace body 1, a heating component, a carbon fiber radiation cover 3, a furnace cover, and a carbon source gas uniformity plate.

[0051] Furthermore, the gas-heated deposition system of the embodiment of the present invention further includes:

[0052] An exhaust gas purification device, one end of which is connected to the exhaust port of the furnace body 1 and the other end of which is connected to the gas inlet of the fuel gas inner tube 221 of the burner, for recycling the exhaust gas after the chemical vapor deposition reaction, wherein the exhaust gas purification device includes an exhaust gas purification device and a fuel gas supply device;

[0053] The combustion air pipeline system 23 before the burner is connected to the air inlet of the burner air outer pipe 222, and is used to supply fresh air to the burner;

[0054] In the embodiment of the present invention, the exhaust gas purification device realizes the recycling of exhaust gas through the exhaust gas circulation pipe, one end of which is connected to the exhaust port of the furnace body 1, and the other end of which is connected to the air inlet of the burner gas inner pipe 221, so as to guide the chemical vapor deposition exhaust gas out of the furnace body 1, and return it to the burner after being processed. The pre-burner combustion air pipeline system 23 provides fresh gas to the burner air outer pipe 222 through the fresh gas supply pipe, and the fresh gas supply pipe is connected to the air inlet of the burner air outer pipe 222.

[0055] In the embodiment of the present invention, the purification device is a first purification device, which is arranged on the tail gas circulation pipe and is used to remove corrosive gases in the tail gas and reduce the temperature of the tail gas. The first purification device includes a tar condenser 8 and a filter 9.

[0056] Preferably, the first purification device is connected to the tail gas circulation pipe at the exhaust port of the furnace body 1. After the tail gas of the chemical deposition reaction is extracted from the exhaust port of the furnace body 1, it first enters the first purification device. The tail gas is purified by the first purification device to remove the corrosive gas in the tail gas, and at the same time, it plays a role in reducing the tail gas temperature. The first purification device is connected to the exhaust port of the furnace body 1 to preliminarily purify the tail gas, remove the corrosive gas in the tail gas, prevent the tail gas from corroding the subsequent equipment or pipelines, and extend the service life of the system.

[0057] It should be noted that the embodiment of the present invention does not impose any specific restrictions on the first purification device. The purpose of the first purification device is: on the one hand, to appropriately reduce the gas temperature, and on the other hand, to remove the corrosive gas that may exist after the chemical reaction. The purpose of removing the corrosive gas contained in the tail gas can be achieved by chemical, physical or physical-chemical methods. The gas generated will be different depending on the deposition reaction, and the purification method selected will be different. Therefore, the corresponding purification method can be selected according to the gas component to be removed in the reaction tail gas. Taking chlorine in the tail gas as an example, the alkaline solution (NaOH solution) absorption method can be used to achieve the purpose of removing chlorine.

[0058] In the embodiment of the present invention, the gas supply device is arranged on the tail gas circulation pipe for supplying natural gas. The gas supply device can be arranged after the first purification device on the tail gas circulation pipe. The tail gas after the reaction enters the tail gas circulation pipe after coming out of the exhaust port of the furnace body 1. After passing through the first purification device, part of the natural gas directly enters the tail gas circulation pipe from the gas supply device. The embodiment of the present invention does not impose specific restrictions on the gas supply device. It can only include the gas supply pipe as long as it can achieve the purpose of supplying natural gas. Alternatively, the tail gas supply can be provided with at least one of a natural gas shut-off valve 19, a natural gas pump and a natural gas flow controller, which can be flexibly selected according to needs.

[0059] In an embodiment of the present invention, the exhaust gas purification device also includes a first pump 10 and / or an exhaust gas shut-off valve 18 and / or an exhaust gas flow controller, which are arranged in the exhaust gas circulation pipe and are used to control the circulating gas volume; the pre-burner combustion air pipeline system 23 is arranged on the fresh gas supply pipe. If other fresh reaction gases are required, more flow controllers can be connected in parallel, which are used to control the flow and proportion of fresh ionized gas and fresh reaction gas respectively, and then control the working pressure in the furnace body 1 to ensure that the ionized gas and reaction gas in the furnace body 1 are always in a stable state.

[0060] The embodiment of the present invention does not specifically limit the first pump 10 and the flow controller, which are used to control the flow and pressure of the gas in the exhaust gas circulation pipe. The first pump 10 can also be a mechanical pump; the flow controller can be a mass flow controller or a volume flow controller, preferably a mass flow controller.

[0061] It is a conventional method to control the gas flow and pressure in the pipeline by means of valves, pumps and flow controllers. The equipment used are all mature products of the prior art. Those skilled in the art can freely choose according to their needs, which will not be described in detail here.

[0062] During the operation of the chemical vapor deposition system, the flow rate of natural gas supply, the flow rate of circulating gas, the flow rate of fresh gas and the working pressure of the furnace body 1 can be controlled by adjusting the first pump 10, the tail gas shut-off valve 18 and the fuel gas shut-off valve 19.

[0063] The exhaust gas purification device also includes: a second purification device, which is arranged on the exhaust gas circulation pipe and is used to remove dust and oil mist in the exhaust gas. It should be noted that the embodiment of the present invention does not specifically limit the second purification device. The second purification device can select a dust removal device, such as a cyclone dust collector, an electrostatic dust collector, to preliminarily remove dust and oil mist in the exhaust gas.

[0064] The second purification device is arranged before the gas supply device and after the second purification device. The second purification device includes a gas collecting device 15 and an oil outlet 16.

[0065] Preferably, in the embodiment of the present invention, the second purification device is arranged before the gas supply device, so that dust and oil mist in the tail gas can be removed through further purification, and combustion after purification can reduce environmental pollution.

[0066] Furthermore, a second pump 17 can be set between the gas supply equipment and the second purification equipment to further provide power for the exhaust gas circulation. The embodiment of the present invention does not make any specific limitation on the second pump 17. A vacuum pump, such as a mechanical pump, can be selected. The first pump 10 can be set as a primary pump, and the second pump 17 can be set as a secondary pump.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. According to the technical essence of the present invention, within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. A gas-fired heating deposition furnace, comprising a furnace body (1) and a heating device for heating an object to be densified in the furnace body (1), characterized in that: The heating device comprises at least one radiation tube (25) extending into the furnace body (1) for heat dissipation and a burner for heating the radiation tube (25) by burning exhaust gas in an exhaust pipe, wherein one end of the radiation tube (25) is a closed end placed in the inner cavity of the furnace body (1) and the other end is an open end penetrating the furnace body (1); the burner is a burner (22) connected to the open end, the burner (22) extending into the radiation tube (25) through the open end, the burner (22) comprising a gas inner tube (221), an air outer tube (222) sleeved outside the gas inner tube (221) and a burner passage (224), and a smoke outlet is also installed between the air outer tube (222) and the open end. The gas pipe (223) is connected to the air inlet of the outer air pipe (222) with a pre-burner combustion air pipeline system (23) for supplying fresh gas to the burner, the smoke outlet of the smoke pipe (223) is connected with a preheating device (24) for preheating the chemical gas to be introduced into the furnace body (1), and the air inlet of the gas inner pipe (221) is connected with a pre-burner gas pipeline system (21) for regulating / stabilizing the pressure, safely cutting off, and regulating the flow of the gas before the burner; the chemical gas is a carbon source gas, and the carbon source gas required by the deposition furnace is heated after passing through the preheating device (24) and then passed into the bottom of the deposition furnace, thereby increasing the temperature of the bottom of the deposition furnace and making the temperature in the deposition furnace more uniform.

2. The gas-fired heating deposition furnace according to claim 1, characterized in that: The inner gas pipe (221) is used to communicate with the air outlet pipe, and the burner channel (224) is respectively communicated with the air outlet of the outer air pipe (222) and the inner gas pipe (221) and extends into the radiation tube (25).

3. The gas-fired heating deposition furnace according to claim 2, characterized in that: The burner channel (224) comprises a columnar portion (224a), one end of the columnar portion (224a) is connected to the air outer tube (222), and the other end is a conical protrusion formed with a conical portion (224b) for mixing fuel gas and air.

4. The gas-fired heating deposition furnace according to claim 3, characterized in that: The smoke pipe (223) is provided with a smoke outlet, and the outer air pipe (222) and the top of the smoke pipe (223), and the bottom and the open end of the smoke pipe (223) are respectively connected via flanges.

5. The gas-fired heating deposition furnace according to claim 1, characterized in that: A sleeve (27) is arranged inside the radiation tube (25), a combustion channel penetrating therein is formed inside the sleeve (27), and the combustion channel is connected to the burner channel (224).

6. The gas-fired heating deposition furnace according to claim 5, characterized in that: A first annular gap is formed between the flue gas pipe (223) and the columnar portion (224a), a second annular gap is formed between the radiation tube (25) and the sleeve (27), and the first annular gap is connected to the second annular gap.

7. Gas-heated deposition furnace system, characterized in that: include: The gas-heated deposition furnace according to any one of claims 1 to 6 further comprises an exhaust gas circulation pipe and an exhaust gas purification device arranged on the exhaust gas circulation pipe, wherein one end of the exhaust gas circulation pipe is connected to the gas outlet of the furnace body (1), and the other end is connected to the gas inlet of the fuel gas inner pipe (221), and is used to recycle the exhaust gas after the chemical vapor deposition reaction in the furnace body (1), and the exhaust gas purification device comprises a primary exhaust gas purification device for removing corrosive gases and cooling the exhaust gas; and a secondary exhaust gas purification device for removing dust and oil mist in the exhaust gas.

8. The gas-fired heating deposition furnace system according to claim 7, characterized in that: It also includes a flue gas preheating pipe and a preheating device (24) arranged on the flue gas preheating pipe, which is used to preheat the chemical gas that will enter the furnace body (1); one end of the preheating device (24) is connected to the flue gas outlet of the flue gas pipe (223), and the other end is used for flue gas discharge.

9. The gas-fired heating deposition furnace system according to claim 8, characterized in that: The exhaust gas circulation pipe is also connected to a fuel gas supply pipe. The exhaust gas circulation pipe is provided with an exhaust gas shut-off valve (18) for controlling the on-off of exhaust gas purified by the exhaust gas purification device after the chemical vapor deposition reaction. The fuel gas supply pipe is provided with a fuel gas shut-off valve (19) for controlling the on-off of fuel gas.

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