CVD (Chemical Vapor Deposition) vertical reaction furnace

Abstract

The utility model relates to the technical field of brake pad manufacturing, and particularly discloses a CVD vertical reacting furnace which comprises a furnace body and a gas mixing tank, the gas mixing tank communicates with the furnace body through a pipeline, a plurality of gas inlet pipes are arranged on one side of the gas mixing tank and communicate with the interior of the gas mixing tank, and the gas inlet pipes are arranged in the tangential direction of the inner wall of the gas mixing tank; a plurality of gases can be simultaneously introduced into the gas mixing tank, the gases enter along the tangential direction of the inner wall of the gas mixing tank and can rotate in the gas mixing tank to be mixed with each other, the inner wall of one side, far away from the gas inlet pipe, of the gas mixing tank is folded towards the middle and is provided with a gas outlet pipe, the gas outlet pipe is communicated with the furnace body, a rotating shaft is arranged in the gas mixing tank along the axis direction, and stirring blades are arranged on the rotating shaft. The motor is used for driving the rotating shaft to drive the blades to rotate so as to further mix the mixed gas, the blades can enable the mixed gas to flow towards the gas outlet pipe, the mixed gas gathers from the periphery to the middle when flowing to the gas outlet pipe, the gas enters the furnace body after being mixed more uniformly, and full reaction of the gas is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of brake pad manufacturing technology, specifically a CVD vertical reactor. Background Technology

[0002] CVD is short for Chemical Vapor Deposition. This technology mainly uses one or more gaseous compounds or elements containing thin film elements to chemically react on the surface of a substrate to form a thin film. It is a process that uses gaseous substances to produce chemical and transport reactions on a solid to generate solid deposits. It generally includes three steps: forming volatile substances; transferring volatile substances to the deposition area; and producing chemical reactions on the solid to generate solid substances.

[0003] Using CVD (Chemical Vapor Deposition) technology, ceramic coatings such as silicon carbide, silicon nitride, or diamond-like carbon can be deposited on the surface of brake pad preforms. This significantly improves the friction coefficient and high-temperature resistance of the brake pads, and reduces thermal fade. During brake pad processing, different types of carbon source gases or inert gas mixtures, such as hydrocarbons or nitrogen, are typically introduced into the CVD reactor. The carbon source gas is heated to a certain temperature, decomposes, and diffuses into the porous preform. Some of the pyrolytic carbon is deposited around the preform and in the voids, bringing the preform density to the required level, forming a carbon brake pad. Since the carbon source gas may be a mixture, and different molecular weights of carbon source gases have different densities, directly introducing the gas into the reactor can lead to poor gas uniformity and incomplete reaction. The mixing rate decreases. To address this, patent CN212800532U discloses a stirring device for gas mixing in a chemical vapor deposition (CVD) furnace. The device includes a mixing tank and a stirring assembly disposed inside the tank. One end of the mixing tank has an air inlet, and the other end is connected to the CVD furnace body. The stirring assembly includes a shaft and at least three blades evenly arranged along the shaft's axial direction. Carbon source gas enters the mixing tank through the air inlet, with the airflow direction perpendicular to the vertical plane of the shaft. The airflow acts on the stirring assembly, causing the blades to rotate, which in turn drives the gas in the mixing tank to flow rapidly. However, this solution has the following drawbacks: the air inlet pipe is parallel to the shaft, and the blades are driven by the airflow of the mixed gas, resulting in uncontrollable blade rotation speed and poor mixing effect. Utility Model Content

[0004] To address the shortcomings of existing technologies, the present invention provides a CVD vertical reactor that solves the problem of poor mixing effect in the mixing tank of existing CVD reactors.

[0005] To solve the above problems, the technical solution adopted by this utility model is: a CVD vertical reactor, including a furnace body and a mixing tank. The mixing tank is connected to the furnace body through a pipe. Multiple air inlet pipes are provided on one side of the mixing tank and are connected to the inside of the mixing tank. The air inlet pipes are arranged along the tangential direction of the inner wall of the mixing tank. The inner wall of the mixing tank away from the air inlet pipes converges towards the middle and is provided with an air outlet pipe. The air outlet pipe is connected to the furnace body. A rotating shaft is provided inside the mixing tank along the axial direction. Stirring blades are provided on the rotating shaft. A motor is used to drive the rotating shaft to drive the blades to rotate.

[0006] Furthermore, the number of air intake pipes is three or four, and they are evenly distributed on the mixing tank.

[0007] Furthermore, the motor is installed on the outside of the mixing tank, and the motor output shaft is connected to the rotating shaft for transmission.

[0008] Furthermore, the intake pipe is provided with a cap, which is threaded into the intake pipe and has a sealing ring.

[0009] Furthermore, the number of stirring blades is three and they are evenly distributed on the rotating shaft.

[0010] Furthermore, the stirring blades are made of plastic, resin, or PVC.

[0011] The beneficial effects of this solution are as follows: Compared with the prior art, the CVD vertical reactor of this utility model is equipped with a mixing tank connected to the furnace body. By setting an inlet pipe along the tangential direction of the inner wall of the mixing tank, multiple gases can be mixed together when they enter the mixing tank. The stirring blades in the mixing tank are electrically driven, so the speed of the stirring blades can be controlled, which can accelerate the mixing and flow of gases. The inner wall of the mixing tank near the outlet pipe narrows towards the middle, so that the mixed gas flows towards the outlet pipe and gathers towards the middle, so that the gas is fully mixed before entering the furnace body for reaction, ensuring a complete reaction. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0013] Figure 2 for Figure 1 Sectional view at point AA;

[0014] In the diagram: 1-furnace body, 2-mixing tank, 3-inlet pipe, 4-outlet pipe, 5-rotating shaft, 6-stirring blade, 7-motor, 8-cover. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0016] Implementation, for example, attached Figures 1 to 2 As shown: A CVD vertical reactor includes a furnace body 1 and a mixing tank 2. The mixing tank 2 is connected to the furnace body 1 via a pipe. Multiple inlet pipes 3 are provided on one side of the mixing tank 2, communicating with the interior of the mixing tank 2. The inlet pipes 3 are arranged tangentially to the inner wall of the mixing tank 2, allowing multiple gases to be simultaneously introduced into the mixing tank 2. These gases, entering tangentially to the inner wall of the mixing tank 2, rotate and mix within the mixing tank 2. The inner wall of the mixing tank 2, away from the inlet pipes 3, tapers towards the center and is provided with an outlet pipe 4, which is connected to the furnace body 1. The mixing tank 2 contains... A rotating shaft 5 is provided along the axial direction, and three stirring blades 6 are provided on the rotating shaft 5. The stirring blades 6 are evenly distributed on the rotating shaft 5. The vibration is small when rotating, which is beneficial to the mixing of gas. A motor 7 is used to drive the rotating shaft 5 to rotate the blades to further mix the gas. The motor 7 is installed on the outside of the mixing tank 2. The output shaft of the motor 7 is connected to the rotating shaft 5 for transmission. The blades can make the mixed gas flow to the gas outlet pipe 4. When the mixed gas flows to the gas outlet pipe 4, it gathers from all sides to the center, so that the gas is more evenly mixed before entering the furnace body 1 to ensure that it reacts fully.

[0017] The air inlet pipe 3 is provided with a cover 8, which is threaded into the air inlet pipe 3 and has a sealing ring. When several types of gas need to be introduced, several covers 8 are opened to prevent gas from flowing out through the air inlet pipe 3. The stirring blade 6 is made of plastic, resin or PVC, which is lightweight and has a smooth surface to facilitate gas flow.

[0018] The specific implementation process is as follows:

[0019] The diagram shows four inlet pipes 3. If the carbon source gas used is methane and the auxiliary gas is nitrogen, the caps 8 of two of the inlet pipes 3 are opened, and gas is introduced into the opened inlet pipes 3. The gas enters the mixing tank 2 and rotates to mix with each other. The motor 7 is started to drive the stirring blades 6 to rotate and stir the gas, and drive the gas to flow to the outlet pipe 4. The mixed gas gathers towards the center at the outlet pipe 4, making the mixing more thorough. After passing through the outlet pipe 4, it enters the furnace body 1 for reaction. After the mixed gas is heated and cracked, the pyrolytic carbon is deposited around the preform and in the gaps, so that the density of the preform reaches the required level, forming carbon brake pads, which improves the friction coefficient and high temperature resistance of the brake pads. The mixing tank 2 of this reactor can make the gas mix thoroughly, ensuring sufficient reaction and reaction rate.

[0020] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A CVD vertical reactor, comprising a furnace body and a mixing tank, wherein the mixing tank is connected to the furnace body via a pipeline, and a plurality of gas inlet pipes are provided on one side of the mixing tank and connected to the interior of the mixing tank, characterized in that: The air inlet pipe is arranged along the tangential direction of the inner wall of the mixing tank. The inner wall of the mixing tank on the side away from the air inlet pipe converges towards the middle and is provided with an air outlet pipe. The air outlet pipe is connected to the furnace body. A rotating shaft is provided in the mixing tank along the axial direction. A stirring blade is provided on the rotating shaft. The rotating shaft is driven by a motor to drive the blade to rotate.

2. The CVD vertical reactor according to claim 1, characterized in that: The number of air intake pipes is three or four, and they are evenly distributed on the mixing tank.

3. The CVD vertical reactor according to claim 1, characterized in that: The motor is installed on the outside of the mixing tank, and the motor output shaft is connected to the rotating shaft for transmission.

4. The CVD vertical reactor according to claim 1, characterized in that: The air intake pipe is equipped with a cap, which is threaded into the air intake pipe and has a sealing ring.

5. The CVD vertical reactor according to claim 1, characterized in that: The number of stirring blades is three, and they are evenly distributed on the rotating shaft.

6. The CVD vertical reactor according to claim 1, characterized in that: The stirring blades are made of plastic, resin, or PVC.

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