Gas replacement system for atmosphere bell-type furnace

Abstract

The utility model discloses a gas replacement system for an atmosphere bell jar furnace. The gas replacement system comprises a furnace body, a hearth and an in-furnace atmosphere control system, the in-furnace atmosphere control system comprises a gas mixing pipeline penetrating through the side wall of the top of the furnace body, a nitrogen pipeline, a hydrogen pipeline, an air pipeline, a humidifying pipeline connected with the gas mixing pipeline in parallel, and an air inlet pipeline connected with the humidifying pipeline, wherein the nitrogen pipeline, the hydrogen pipeline and the air pipeline are arranged outside the furnace body and communicated with the gas mixing pipeline; the gas inlet pipelines are communicated with the gas mixing pipeline and are longitudinally inserted into an inner cavity of the hearth from the top of the hearth; a plurality of air inlet holes which are uniformly distributed from top to bottom are formed in the pipe wall of the inner side of the air inlet pipeline, a pressure sensor is arranged on the inner side wall of the furnace body, and an MFC gas flow controller is arranged on each of the nitrogen pipeline, the hydrogen pipeline and the air pipeline; the device can prevent impurities at the bottom in the furnace from being raised to pollute products during vacuum breaking, and simultaneously realizes accurate control of gas flow under vacuum degrees at all stages, namely, to-be-sintered products are not blown away, and gas replacement time is shortened.

Description

Technical Field

[0001] The utility model belongs to the field of electronic component production equipment, in particular to a gas replacement system for an atmosphere bell furnace. Background Art

[0002] Base metal inner electrode MLCC products require the use of an atmosphere bell furnace during the sintering process. In the initial stage of operation, the atmosphere bell furnace needs to replace the gas in the furnace to achieve a stable and controllable atmosphere in the furnace. One of the commonly used methods is to evacuate and break the vacuum in the furnace to complete the atmosphere replacement. The current design is to open the furnace bricks at the bottom of the furnace bed as a gas channel for evacuating and breaking the vacuum. However, with the use of the equipment, the loose structure of the furnace bricks is prone to produce fiber powder that falls near the gas channel. At the same time, the rust produced by the rust on the inner wall of the carbon steel shell of the sintering furnace will also fall and accumulate in the gas channel. The above two impurities will be lifted and blown to the surface of the product when the vacuum is broken, and react with the product during the high-temperature sintering process to cause fatal defects.

[0003] If the gas vacuum breaking pipeline is simply placed at the air inlet during normal operation, the air inlet will blow directly into the product. In the early stage of vacuum breaking, when the vacuum degree is high, the gas flow rate is high, which can easily blow the product away. If the gas flow rate is simply reduced, the vacuum breaking time will increase. Summary of the invention

[0004] The utility model aims to provide a gas replacement system for an atmosphere bell furnace, which can prevent impurities at the bottom of the furnace from being lifted up and contaminating products when the vacuum is broken, and at the same time, the vacuum degree in the furnace is identified by a pressure sensor, and combined with MFC gas flow controllers on nitrogen pipelines, hydrogen pipelines and air pipelines, the gas flow rate can be accurately controlled under the vacuum degree of each stage, so as to achieve the purpose of not blowing away the products to be sintered and reducing the gas replacement time.

[0005] The technical solution of the utility model is: a gas replacement system for an atmosphere bell furnace, comprising a furnace body, a furnace chamber arranged inside the furnace body, and a furnace atmosphere control system passing through the top side wall of the furnace body and connected with the interior of the furnace chamber; the furnace atmosphere control system comprises a gas mixing pipeline passing through the top side wall of the furnace body, a nitrogen pipeline, a hydrogen pipeline and an air pipeline placed outside the furnace body and connected with the gas mixing pipeline, a humidification pipeline connected in parallel with the gas mixing pipeline, and a plurality of air intake pipelines connected with the gas mixing pipeline and longitudinally inserted into the internal cavity of the furnace chamber from the top; a plurality of air intake holes evenly arranged from top to bottom are arranged on the inner tube wall of the air intake pipeline, a pressure sensor is arranged on the inner wall of the furnace body, and an MFC gas flow controller is respectively arranged on the nitrogen pipeline, the hydrogen pipeline and the air pipeline.

[0006] As a preferred technical solution, a first control valve and a second control valve connected in series are arranged on the gas mixing pipeline, and a third control valve and a humidification water tank connected in series are arranged on the humidification pipeline, and the third control valve and the humidification water tank are connected in series with the first control valve.

[0007] As a preferred technical solution, the gas replacement system also includes a vacuum channel arranged on a side wall of the bottom of the furnace, a vacuum pipeline arranged on a side wall of the bottom of the furnace body and corresponding to the vacuum channel, and a vacuum pump connected to the vacuum pipeline.

[0008] As a preferred technical solution, the gas replacement system also includes a main controller electrically connected to the pressure sensor, the MFC gas flow controller, and the vacuum pump and having a touch screen.

[0009] As a preferred technical solution, the furnace body adopts a carbon steel furnace shell with a hollow structure inside.

[0010] As a preferred technical solution, a high-temperature refractory material layer is provided on the inner wall of the furnace, and the high-temperature refractory material layer is formed by splicing a plurality of high-temperature refractory furnace bricks, and adjacent high-temperature refractory furnace bricks are squeezed against each other to form a sealed whole.

[0011] As a preferred technical solution, the nitrogen pipeline, the hydrogen pipeline and the air pipeline are respectively connected to a nitrogen source, a hydrogen source and an air source.

[0012] The advantages of the utility model are:

[0013] 1. The utility model is used for the gas replacement system of the atmosphere bell furnace, which can prevent the impurities at the bottom of the furnace from being lifted up and contaminating the products when the vacuum is broken. At the same time, the vacuum degree in the furnace is identified by the pressure sensor, and the MFC gas flow controllers on the nitrogen pipeline, hydrogen pipeline and air pipeline are combined to realize the precise control of the gas flow at each stage of vacuum degree, so as to achieve the purpose of not blowing away the products to be sintered and reducing the gas replacement time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. The drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0016] Figure 1 It is a structural schematic diagram of the utility model;

[0017] Wherein: 1 furnace body, 2 furnace, 3 gas mixing pipeline, 4 nitrogen pipeline, 5 hydrogen pipeline, 6 air pipeline, 7 humidification pipeline, 8 air inlet pipeline, 9 air inlet hole, 10 pressure sensor, 11 MFC gas flow controller, 12 first control valve, 13 second control valve, 14 third control valve, 15 humidification water tank, 16 vacuum channel, 17 vacuum pipeline, 18 vacuum pump. DETAILED DESCRIPTION

[0018] The above scheme is further described below in conjunction with specific examples. It should be understood that these examples are used to illustrate the utility model and are not limited to the scope of the utility model. The implementation conditions used in the examples can be further adjusted according to the conditions of the specific manufacturer, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0019] Example: Refer to Figure 1 As shown, a gas replacement system for an atmosphere bell furnace comprises a furnace body 1, a furnace chamber 2 arranged inside the furnace body 1, and a furnace atmosphere control system passing through the top side wall of the furnace body 1 and connected with the interior of the furnace chamber 2; wherein the furnace atmosphere control system comprises a gas mixing pipeline 3 passing through the top side wall of the furnace body 1, a nitrogen pipeline 4, a hydrogen pipeline 5 and an air pipeline 6 arranged outside the furnace body 1 and connected with the gas mixing pipeline 3, a humidification pipeline 7 connected in parallel with the gas mixing pipeline 3, and a plurality of air inlet pipelines 8 connected with the gas mixing pipeline 3 and inserted longitudinally from the top of the furnace chamber 2 into the internal cavity thereof; a plurality of air inlet holes 9 evenly arranged from top to bottom are arranged on the inner wall of the air inlet pipeline 8, a pressure sensor 10 is arranged on the inner wall of the furnace body 1, and an MFC gas flow controller 11 is respectively arranged on the nitrogen pipeline 4, the hydrogen pipeline 5 and the air pipeline 6.

[0020] In this embodiment, a first control valve 12 and a second control valve 13 connected in series are arranged on the gas mixing pipeline 3, and a third control valve 14 and a humidification water tank 15 connected in series are arranged on the humidification pipeline 7. At the same time, the third control valve 14 and the humidification water tank 15 are connected in parallel with the first control valve 12. The ratio of wet gas to dry gas is controlled by the humidification water tank 15 to achieve the purpose of flexibly adjusting the water content in the furnace.

[0021] In this embodiment, the gas replacement system also includes a vacuum channel 16 arranged on a side wall of the bottom of the furnace 2, a vacuum pipeline 17 arranged on a side wall of the bottom of the furnace body 1 and corresponding to the vacuum channel 16, and a vacuum pump 18 connected to the vacuum pipeline 17. The furnace is evacuated by the vacuum pump 18, the vacuum pipeline 17, and the vacuum channel 16.

[0022] In this embodiment, the gas replacement system also includes a main controller (not shown in the figure) which is electrically connected to the pressure sensor 10, the MFC gas flow controller 11, and the vacuum pump 18 and has a touch screen. The vacuum degree in the furnace is identified by the pressure sensor 10, and the touch screen sets the gas flow rate at each stage of breaking the vacuum. In combination with the MFC gas flow controller 11 on the nitrogen pipeline 4, the hydrogen pipeline 5, and the air pipeline 6, the gas flow rate at each stage of vacuum degree is precisely controlled, thereby achieving the purpose of not blowing away the sintered products and reducing the gas replacement time.

[0023] In this embodiment, the furnace body 1 adopts a carbon steel furnace shell with a hollow structure inside, and a high-temperature refractory material layer is provided on the inner wall of the furnace 2. The high-temperature refractory material layer is formed by splicing a plurality of high-temperature refractory furnace bricks, and adjacent high-temperature refractory furnace bricks are squeezed against each other to form a sealed whole.

[0024] In this embodiment, the nitrogen pipeline 4, the hydrogen pipeline 5 and the air pipeline 6 are connected to the nitrogen source, the hydrogen source and the air source respectively.

[0025] In this embodiment, the gas volume in the furnace is 1500L. When the vacuum is broken in the furnace, at 0-10KPa, the limit flow rate for the product not to be blown away is 30L / min, at 10-40KPa, the limit flow rate for the product not to be blown away is 100L / min, and at 40-101KPa, the limit flow rate for the product not to be blown away is 200L / min. The vacuum breaking gas flow value of each stage can be set accordingly, and the total time is: 1500*(10 / 101) / 30+1500*(30 / 101) / 100+1500*(61 / 101) / 200≈14min.

[0026] Compared with the original existing design, the time it takes should be: 1500 / 30=50min, thus saving 36min and reducing the gas replacement time.

[0027] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A gas replacement system for an atmosphere bell furnace, comprising a furnace body, a furnace chamber arranged inside the furnace body, and a furnace atmosphere control system passing through the top side wall of the furnace body and communicating with the interior of the furnace chamber; characterized in that: The furnace atmosphere control system includes a gas mixing pipeline passing through the top side wall of the furnace body, a nitrogen pipeline, a hydrogen pipeline and an air pipeline placed outside the furnace body and connected to the gas mixing pipeline, a humidification pipeline connected in parallel with the gas mixing pipeline, and a plurality of air intake pipelines connected to the gas mixing pipeline and inserted longitudinally from the top of the furnace into the internal cavity thereof; a plurality of air intake holes evenly arranged from top to bottom are arranged on the inner pipe wall of the air intake pipeline, a pressure sensor is arranged on the inner wall of the furnace body, and an MFC gas flow controller is respectively arranged on the nitrogen pipeline, the hydrogen pipeline and the air pipeline.

2. The gas replacement system for an atmosphere bell furnace according to claim 1, characterized in that: A first control valve and a second control valve connected in series are arranged on the gas mixing pipeline, and a third control valve and a humidification water tank connected in series are arranged on the humidification pipeline. Meanwhile, the third control valve and the humidification water tank are connected in parallel with the first control valve.

3. The gas replacement system for an atmosphere bell furnace according to claim 1, characterized in that: The gas replacement system also includes a vacuum channel arranged on a side wall of the furnace bottom, a vacuum pipeline arranged on a side wall of the furnace bottom and corresponding to the vacuum channel, and a vacuum pump connected to the vacuum pipeline.

4. The gas replacement system for an atmosphere bell furnace according to claim 3, characterized in that: The gas replacement system also includes a main controller which is electrically connected to the pressure sensor, the MFC gas flow controller, and the vacuum pump and has a touch screen.

5. The gas replacement system for an atmosphere bell furnace according to claim 1, characterized in that: The furnace body adopts a carbon steel furnace shell with a hollow structure inside.

6. The gas replacement system for an atmosphere bell furnace according to claim 1, characterized in that: A high-temperature refractory material layer is arranged on the inner wall of the furnace, and the high-temperature refractory material layer is formed by splicing a plurality of high-temperature refractory furnace bricks, and adjacent high-temperature refractory furnace bricks are squeezed against each other to form a sealed whole.

7. The gas replacement system for an atmosphere bell furnace according to claim 1, characterized in that: The nitrogen pipeline, the hydrogen pipeline and the air pipeline are respectively connected to a nitrogen source, a hydrogen source and an air source.

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