Powder feeder capable of uniformly dispersing multiple powders

Abstract

The utility model relates to the technical field of metal powder conveying devices, and discloses a multi-powder uniform dispersion powder feeder, which comprises a plurality of powder containers which are mutually independent and powder feeding channels which are matched with the powder containers, the tail ends of the powder feeding channels intersect and communicate with a turbulent flow generation mechanism, the turbulent flow generation mechanism comprises a turbulent flow generation channel and a tangential airflow channel communicating with one side of the turbulent flow generation channel in a penetrating mode, and the included angle alpha between the tangential airflow channel and the turbulent flow generation channel is an acute angle. A spiral structure is arranged at the rear end of the position, connected with the tangential airflow channel, in the turbulent flow generation channel, a powder feeding needle is arranged at the tail end of the turbulent flow generation channel, and a filtering type deflation valve is arranged on the turbulent flow generation channel. According to the plasma spraying device, various problems such as macroscopic layering and microscopic segregation caused by different physical properties and uneven mixing of various metal powders in plasma spraying can be effectively avoided.

Description

Technical Field

[0001] This utility model relates to the technical field of metal powder conveying devices, and in particular to a multi-powder uniform dispersion feeder. Background Technology

[0002] Plasma spraying is a spraying method that uses high-temperature plasma to melt powder materials and then spray them onto the surface of a substrate to form a coating. It has the advantages of strong material applicability, high coating quality and deposition efficiency, and is commonly used in hydrogen production electrode grids to produce porous Raney nickel catalysts.

[0003] The traditional electrode mesh spraying process involves mixing nickel powder, aluminum powder, and other powders using a double-cone mixer or a three-dimensional mixer → drying to remove moisture and increase fluidity → plasma spraying. The melting points, densities, and thermal conductivity of metals such as nickel and aluminum differ significantly, leading to macroscopic stratification and microscopic segregation during mixing, drying, transporting, powder feeding, and spraying. ① Compositional segregation and uneven coating: Uneven distribution of nickel and aluminum in the coating, with localized areas rich in nickel or aluminum, affects coating performance (e.g., corrosion resistance, bonding strength). ② Mismatched melting states: Aluminum powder melts or vaporizes prematurely, while nickel powder does not completely melt, resulting in high coating porosity or poor adhesion. ③ Aluminum powder surface oxidation generates Al2O3 inclusions, reducing coating density and bonding strength. These factors combined lead to thermal stress and cracking, affecting product performance, lifespan, and stability.

[0004] Traditional improvement methods include (1) using mechanical coating to combine nickel and aluminum together to form nickel-coated aluminum or aluminum-coated nickel. However, this reduces fluidity and results in poor coating uniformity; (2) using metallurgical smelting to make alloy powder to prevent segregation, but in the strong alkaline and high-temperature environment of the hydrogen production electrode network, the catalytic performance is not significantly improved, the cost is high, and the presence of aluminum affects the long-term stability of the electrode; (3) adding binders to improve segregation, but this introduces impurities, contaminates the coating, and causes uncontrollable consequences. Utility Model Content

[0005] Purpose of the utility model: In view of the problems existing in the prior art, this utility model provides a multi-powder uniform dispersion powder feeder. This utility model can effectively avoid various problems such as macroscopic layering and microscopic segregation that occur in plasma spraying due to the different physical properties of various metal powders and uneven mixing.

[0006] Technical Solution: This utility model provides a multi-powder uniform dispersion feeder, comprising: several independent powder containers and powder feeding channels configured in conjunction with each powder container; the ends of each powder feeding channel converge and are connected to a turbulence generating mechanism; the turbulence generating mechanism includes a turbulence generating channel and a tangential airflow channel that penetrates and communicates with one side of the turbulence generating channel; the included angle α between the tangential airflow channel and the turbulence generating channel is an acute angle; a spiral structure is provided at the rear end of the turbulence generating channel where it connects to the tangential airflow channel; a powder feeding needle is provided at the end of the turbulence generating channel; and a filter-type venting valve is provided on the turbulence generating channel.

[0007] Furthermore, the powder container includes a frame and a powder barrel mounted on the frame. A powder feeding mechanism is provided between the powder outlet at the lower end of the powder barrel and the frame. The powder feeding mechanism includes a powder feeding screw assembly and a powder feeding motor. One end of the powder feeding screw assembly is connected to the powder feeding motor, and the other end of the powder feeding screw assembly is provided with a powder outlet that extends into the powder feeding channel.

[0008] Furthermore, a drive motor is provided on the powder container, and a stirring mechanism is provided inside the powder container, with the top end of the stirring mechanism connected to the drive end of the drive motor.

[0009] Furthermore, a gas mass flow meter is installed on the tangential airflow channel.

[0010] Furthermore, a pressure sensor is also installed on the turbulence generation channel.

[0011] Preferably, the pitch of the spiral structure is 2-4 mm.

[0012] Preferably, the filter-type venting valve is a nickel felt filter-type venting valve. The nickel felt filter-type venting valve can discharge excess carrier gas. In conjunction with a pressure sensor, the nickel felt filter-type venting valve can adjust the carrier gas flow rate according to the characteristics of the mixed powder and plasma, so that the powder outlet velocity matches the plasma.

[0013] Beneficial effects: Compared with the prior art, this invention can effectively prevent problems such as macroscopic powder stratification and microscopic segregation during the production of hydrogen evolution electrode mesh. Specific beneficial effects are as follows:

[0014] (1) This utility model designs an independent powder container to transport various metal powders that need to be mixed to the turbulence generating mechanism, so that they are mixed in the turbulence generating mechanism, thus avoiding segregation caused by traditional metal powder premixing;

[0015] (2) In this invention, a tangential airflow channel is provided through one side of the turbulence generation channel. The tangential airflow channel introduces tangential airflow, which fluidizes the layered powder conveyed by each powder conveying channel, thereby keeping the powder in a suspended state and reducing stratification caused by gravity settling; at the same time, it increases the flow rate of the powder conveying carrier gas, which increases the power for the subsequent spiral powder conveying.

[0016] (3) The present invention is designed with a spiral structure in the turbulence generation channel to convey the mixed powder in a spiral manner, forming a swirling flow field, which further forces the mixed powder to be evenly dispersed. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the powder container in Embodiment 1 of the present invention;

[0018] Figure 2 This is a schematic diagram of the powder feeding channel and turbulence generation mechanism in Embodiment 1 of the present invention;

[0019] Figure 3 This is a detailed structural diagram of the turbulence generating mechanism in Embodiment 1 of the present invention;

[0020] Figure 4 This is a schematic diagram of the powder feeding channel and turbulence generation mechanism in Embodiment 2 of the present invention;

[0021] Figure 5 Electron micrographs of the electrode mesh (b) obtained by spraying using the apparatus of Embodiment 1 of the present invention and the electrode mesh (a) obtained by spraying using conventional methods are shown.

[0022] Illustrations: 1. Powder container; 101. Frame; 102. Powder hopper; 103. Powder feeding mechanism; 1031. Powder feeding screw assembly; 1032. Powder feeding motor; 1033. Powder outlet; 104. Drive motor; 105. Stirring mechanism; 2. Powder feeding channel; 3. Turbulence generating mechanism; 301. Turbulence generating channel; 302. Tangential airflow channel; 303. Spiral structure; 304. Powder feeding needle; 305. Filter-type vent valve; 306. Pressure sensor; 307. Gas mass flow meter. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the embodiments.

[0024] Implementation method 1:

[0025] This embodiment provides a powder feeder for uniformly dispersing nickel and aluminum dual powders in an electrode mesh plasma spraying process, as detailed below:

[0026] Includes: powder containers 1 containing nickel powder and aluminum powder respectively, such as... Figure 1As shown, the powder container 1 includes a frame 101 and a powder barrel 102 mounted on the frame 101. A powder feeding mechanism 103 is provided between the powder outlet at the lower end of the powder barrel 102 and the frame 101. The powder feeding mechanism 103 includes a powder feeding screw assembly 1031 and a powder feeding motor 1032. One end of the powder feeding screw assembly 1031 is connected to the powder feeding motor 1032, and the other end of the powder feeding screw assembly 1031 is provided with a powder outlet 1033. A drive motor 104 is provided above the powder container 1. The powder container 1 has a stirring mechanism 105 inside, and the top end of the stirring mechanism 105 is connected to the drive end of the drive motor 104.

[0027] Optionally, based on physical properties, nickel powder and aluminum powder can be designed as spherical powders (good flowability), with nickel powder particle size of 5-80 μm and D50 of 25-45 μm; aluminum powder particle size of 50-150 μm and D50 of 80-100 μm (to reduce the difference in melting points that leads to poor sintering and melting of the powder); then vacuum dried and loaded into powder container 1.

[0028] Optionally, the vacuum drying conditions are: vacuum degree 0.1 Pa, temperature 80-90℃, time 4-5 hours, ensuring that the powder moisture content is ≤0.1%.

[0029] like Figure 2-3 As shown, the powder outlet 1033 below the powder container 1 containing nickel powder extends into the nickel powder feeding channel 2, and the powder outlet 1033 below the powder container 1 containing aluminum powder extends into the aluminum powder feeding channel 2. The ends of the nickel powder feeding channel 2 and the aluminum powder feeding channel 2 converge and are connected to the turbulence generating mechanism 3. The turbulence generating mechanism 3 includes a turbulence generating channel 301 and a tangential airflow channel 302 that is connected to one side of the turbulence generating channel 301. A gas mass flow meter 307 is installed on the tangential airflow channel 302. The angle α between the tangential airflow channel 302 and the turbulence generating channel 301 is an acute angle. A spiral structure 303 is installed at the rear end of the turbulence generating channel 301 where it connects to the tangential airflow channel 302. The pitch of the spiral structure 303 is 2-4 mm. A powder feeding needle 304 is installed at the end of the turbulence generating channel 301. A nickel felt filter-type venting valve 305 and a pressure sensor 306 are installed on the turbulence generating channel 301.

[0030] Optionally, the tangential airflow introduced by the tangential airflow channel 302 has a flow rate of 5-7 L / min and a pressure of 0.3 MPa.

[0031] Optionally, the turbulence generation channel 301 has an inner diameter of 8 mm, a length of 300-500 mm, and is made of 316L stainless steel.

[0032] The working principle of the nickel and aluminum dual-powder uniform dispersion feeder for the electrode mesh plasma spraying process provided in this embodiment is as follows: The drive end of the drive motor of the powder barrel containing nickel powder and aluminum powder respectively drives the stirring mechanism inside the powder barrel to rotate, thereby stirring the nickel powder and aluminum powder filled in the powder barrel respectively. The drive end of the powder feeding motor drives the screw in the powder feeding screw assembly to rotate, thereby sending the stirred nickel powder and aluminum powder into their respective matching powder feeding channels through the powder outlet. The nickel powder in the nickel powder feeding channel and the aluminum powder in the aluminum powder feeding channel meet and mix at the ends of the two channels and enter the turbulence generation channel. The tangential airflow introduced in the tangential airflow channel enters the turbulence generation channel through the through-hole on one side of the turbulence generation channel, fluidizing the metal powder in each powder feeding channel, thereby keeping the powder in a suspended state, pushing the powder into the spiral structure, and spirally conveying the mixed powder to form a swirling flow field, further forcing the mixed powder to be uniformly dispersed. The uniformly dispersed metal powder is sprayed out by the powder feeding needle and sprayed onto the electrode mesh substrate by the flame jet sprayed by the plasma spray gun set below the powder feeding needle.

[0033] Preferably, a gas mass flow meter is installed on the tangential airflow channel to control the flow rate of the tangential airflow introduced into the tangential airflow channel.

[0034] Preferably, a pressure sensor and a nickel felt filter-type vent valve are installed on the turbulence generation channel: on the one hand, the operator can directly control the carrier gas flow rate by adjusting the tangential airflow rate and the vent valve flow rate according to the state of the powder ejected from the powder feeding needle, so as to match the powder outlet velocity with the plasma. Alternatively, the operator can control the carrier gas flow rate by adjusting the tangential airflow rate and the vent valve flow rate according to the value of the pressure sensor, so as to match the powder outlet velocity with the plasma.

[0035] Optionally, the plasma spraying process parameters are as follows:

[0036] Plasma power: 40 kW, main gas (argon) flow rate: 50 L / min, auxiliary gas (hydrogen) flow rate: 10 L / min.

[0037] Substrate: 316L stainless steel mesh (1 mm aperture), preheating temperature 200℃.

[0038] Spraying distance: 120 mm, spraying time: 10 minutes.

[0039] The electrode mesh obtained by spraying using the apparatus of this embodiment and the electrode mesh obtained by conventional spraying were tested, as follows:

[0040] Table 1 shows a comparison of the electrochemical uniformity of the electrode grid:

[0041]

[0042] Implementation Method 2:

[0043] This embodiment is largely the same as embodiment 1, except that, as Figure 4 As shown, this embodiment is a nickel, aluminum, and zinc multi-powder uniform dispersion feeder for the electrode mesh plasma spraying process. Powder containers 1 containing nickel powder, aluminum powder, and zinc powder are respectively provided. The powder outlet 1033 below the powder container 1 containing nickel powder extends into the nickel powder feeding channel 2, the powder outlet 1033 below the powder container 1 containing aluminum powder extends into the aluminum powder feeding channel 2, and the powder outlet 1033 below the powder container 1 containing zinc powder extends into the zinc powder feeding channel 2. The ends of the nickel powder feeding channel 1, the aluminum powder feeding channel 1, and the zinc powder feeding channel 1 converge and are connected to the turbulence generating mechanism 3.

[0044] Apart from the above, this implementation method is exactly the same as implementation method 1, and will not be described again here.

[0045] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent transformations or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A multi-powder uniform dispersion powder feeder, characterized by, Comprising: A plurality of independent powder loading containers and powder feeding channels provided in a matching manner with each of the powder loading containers. The ends of each of the powder feeding channels converge and are connected to a turbulence generating mechanism. The turbulence generating mechanism includes a turbulence generating channel and a tangential air flow channel that penetrates and communicates with one side of the turbulence generating channel. The included angle α between the tangential air flow channel and the turbulence generating channel is an acute angle. A spiral structure is provided at the rear end of the turbulence generating channel at the connection with the tangential air flow channel. A powder feeding needle is provided at the end of the turbulence generating channel. A filter type air release valve is provided on the turbulence generating channel.

2. The multi-powder uniform dispersion powder feeder of claim 1, wherein: The powder loading container includes a frame and a powder barrel provided on the frame. A powder feeding mechanism is provided between the powder outlet at the lower end of the powder barrel and the frame. The powder feeding mechanism includes a powder feeding screw assembly and a powder feeding motor. One end of the powder feeding screw assembly is connected to the powder feeding motor, and a powder outlet is provided at the other end of the powder feeding screw assembly. The powder outlet extends into the powder feeding channel.

3. The multi-powder uniform dispersion powder feeder of claim 2, wherein: A driving motor is provided on the powder loading container, and a stirring mechanism is provided inside the powder loading container. The top end of the stirring mechanism is connected to the driving end of the driving motor.

4. The multi-powder uniform dispersion powder feeder of claim 1, wherein: A gas mass flowmeter is provided on the tangential air flow channel.

5. The multi-powder uniform dispersion powder feeder of claim 1, wherein: A pressure sensor is also provided on the turbulence generating channel.

6. The multi-powder uniform dispersion feeder according to claim 1, characterized in that: The pitch of the spiral structure is 2 - 4 mm.

7. The multi-powder uniform dispersion powder feeder of claim 1, wherein: The filter type air release valve is a nickel felt filter type air release valve.

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