A Laval nozzle device for uniform powder output

Abstract

The invention discloses a Laval nozzle device for uniform powder output, and relates to the technical field of nozzle devices. The nozzle device comprises a nozzle, an anti-blocking box is installed on one side of the nozzle, a mixing box is installed on one side of the anti-blocking box, a powder outlet is installed on one side of the mixing box, and an air inlet 1 and an air inlet 2 are installed on one side of the mixing box. The nozzle device can ensure uniform spraying of powder material through the nozzle, prevent powder from being blocked inside the nozzle through the anti-blocking box, and uniformly mix gas and powder through the mixing box to ensure consistency and uniformity of powder output. The design of the two air inlets enables the nozzle device to introduce an appropriate amount of air when working, so as to help the powder to be evenly dispersed. The nozzle device of the invention can effectively solve the shortcomings of traditional nozzle devices in powder output uniformity, and greatly improve the working efficiency of the nozzle device and the uniformity of spraying.

Description

Technical Field

[0001] The invention relates to the technical field of nozzle devices, in particular to a Laval nozzle device for uniformly discharging powder. Background Art

[0002] At present, with the rapid development of surface thin film deposition technology, AD spraying technology (Aerosol Deposition Method) is unique among them. AD ​​spraying refers to a surface deposition technology that uses high-speed airflow to float, atomize and accelerate ultra-fine spray powder particles at room temperature or low vacuum environment, and then deposits them on the clean substrate surface at high speed to form a coating. The main devices of AD spraying equipment are composed of gas source, flow meter, atomization generator, Laval nozzle, low vacuum deposition chamber and vacuum pump body. The most important process parameters include deposition chamber pressure, nozzle design, spray powder particle spray uniformity and spray temperature. The design of Laval nozzle plays a vital role in deposition quality.

[0003] The Laval nozzle is specially designed, i.e. the gradually contracting shape inside the nozzle, so that the high-pressure gas drives the deposited powder particles to accelerate rapidly at a supersonic speed when flowing in the nozzle. This acceleration greatly improves the injection efficiency and enables the powder particles to generate greater kinetic energy during spraying. Although the Laval nozzle can increase the injection speed of the powder particles, a series of complex fluid mechanics phenomena will be formed when the incoming airflow and the main injection airflow intersect, leading to the formation of vortex phenomena and uneven powder discharge of the powder particles, which affects the spraying quality; and when passing through the nozzle, due to the increase in speed and the decrease in pressure, a certain amount of energy loss will be generated. Under certain circumstances, this energy loss may be more obvious. Studies have found that controlling the temperature of the powder particles at the nozzle outlet is also positively correlated with the fluidity of the powder particle injection airflow and the uniform distribution of the powder. The quality of the AD spray coating has a direct impact on the uniformity of the spray powder outlet, and the development and commissioning costs of the uniform powder delivery air pipeline and the heating air pipeline are relatively high.

[0004] In summary, a Laval nozzle device with uniform powder output is in urgent need of development.

[0005] Although the prior art has disclosed an atomizing nozzle and method for producing powder, there are still some shortcomings. Specifically, in the actual production operation process, the nozzle device lacks a corresponding mixing device before spraying, resulting in uneven spraying of the sprayed powder, affecting the spraying quality. In addition, the powder outlet end of the nozzle device lacks a corresponding anti-blocking device, which will cause congestion of the nozzle during long-term use, affecting the spraying quality. Summary of the invention

[0006] The object of the present invention is to provide a Laval nozzle device for uniform powder discharge, so as to solve the problems raised in the prior art.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a Laval nozzle device for uniform powder discharge, the nozzle device comprising a nozzle, an anti-blocking box installed on one side of the nozzle, a mixing box installed on one side of the anti-blocking box, and a powder outlet, air inlet 1 and air inlet 2 installed on one side of the mixing box. The nozzle adopts a Laval shape, which can form a low-pressure area under the action of high-speed airflow, thereby effectively sucking in the powder and accelerating the injection. The structure inside the anti-blocking box prevents the powder from accumulating and clogging in the box through vibration. The structure inside the mixing box continuously mixes and stirs the gas and powder to achieve a uniform mixing effect. The air inlet 1 and the air inlet 2 are respectively connected to independent air sources. By accurately controlling the air intake volume and air intake speed, the dead angle in the process of gas entry can be effectively reduced, the contact area between the gas and the powder can be increased, and the mixing uniformity can be improved.

[0008] The nozzle mainly includes a regional particle uniformity zone, a particle entry zone, a particle acceleration zone, a particle emission zone, a heating system and a cooling system. The particle uniformity zone includes a particle uniformity port and a particle uniformity cavity. The particle uniformity port is fixed inside the nozzle. The particle uniformity port is a structure with a conical top opening. The particle uniformity cavity is located on one side of the particle uniformity port. The particle entry zone includes a convergent pipe, which is located at the narrow mouth of the nozzle. The particle acceleration zone includes a narrow mouth and an expansion pipe, which is located on one side of the convergent pipe, and the expansion pipe is located on one side of the narrow mouth. The particle emission zone includes an outlet, and the particle uniformity cavity, the narrow mouth, and the outlet are located inside the nozzle. The particle uniformity port is used to ensure that the particles can be preliminarily homogenized before entering the nozzle, which helps the particles to be more evenly distributed when passing through. The particle uniformity cavity is used to further accelerate the particles to achieve the required injection speed. The convergent pipe is used to further concentrate the particles to improve the accuracy and efficiency of the injection. The narrow mouth is used to further control the shape and direction of the particle flow to ensure the stability and consistency of the particle flow during injection. The outlet is used to ensure the smooth output of the particle flow.

[0009] The cooling system includes a coolant inlet pipe, a coolant chamber, and a coolant outlet pipe. The coolant chamber is located inside the nozzle, the coolant inlet pipe is located away from the expansion pipe, the coolant outlet pipe is located close to the expansion pipe, and the coolant inlet pipe, the coolant outlet pipe and the coolant chamber are connected. The coolant enters the pipe coolant chamber from the coolant inlet and is discharged from the coolant outlet pipe. The coolant chamber cools the nozzle shell to reduce the size change of the nozzle caused by thermal expansion.

[0010] The heating system of the nozzle is located in the high-speed particle emission area, and the heating system includes a heating coil. An annular groove is opened inside the nozzle, and the annular groove is located inside the coolant chamber. A heating coil is installed in the groove, and the heating coil is a spiral structure. The heating coil heats the internal particles by transferring heat to the tube wall through the heating resistance wire, and preheats the outlet powder particles, which is more helpful to increase the temperature and kinetic energy of the particles, thereby enhancing the spraying uniformity performance and efficiency of the nozzle.

[0011] The anti-blocking box is provided with a cylindrical groove inside, protrusions are provided on both sides of the anti-blocking box, a sleeve is installed in the groove, the sleeve is fixed on the inner wall of the groove of the anti-blocking box, a vibrating cylinder is sleeved inside the sleeve, and multiple groups of inclined fences are provided on the inner wall of the vibrating cylinder, a protrusion is provided on one side of the vibrating cylinder, and springs 1 and 2 are provided on both sides of the sleeve, the spring 1 is located on the nozzle side, and the spring 2 is located on the mixing box side. The groove structure is used to fix and support the internal components, the protrusion increases the stability of the structure, and provides support for springs 1 and 2. When the vibrating cylinder is working, it vibrates under the drive of gas and powder, which helps to prevent material blockage. Springs 1 and 2 are used to provide buffering for the vibrating cylinder when it is under pressure.

[0012] A mixing chamber is provided inside the mixing box, a rotating shaft is provided inside the mixing chamber, the rotating shaft is rotatably connected to the inner wall of the mixing box, a fixing ring 1 and two fixing rings 2 are installed on the rotating shaft, the fixing ring 1 is located in the middle of the rotating shaft, baffles 1 are installed on both sides of the fixing ring 1, a scraper 1 is installed on one side of the baffle 1, fixing rings 2 are installed on both sides of the rotating shaft, baffles 2 are installed on both sides of the fixing ring 2, and scraper 2 is installed on one side of the baffle 2. The mixing chamber is used to contain and mix gas and powder, the rotating shaft provides support for the mixing component, the function of baffles 1 and 2 is to drive the rotating shaft to rotate under the blowing of gas and powder, and also to stir the mixed gas and powder, scrapers 1 and 2 scrape the powder on the inner wall of the mixing chamber, improve the mixing efficiency, and ensure that the gas and powder can be fully mixed.

[0013] The powder outlet is located at the center of one side of the mixing box, the powder outlet is connected to the mixing chamber, the air inlet 1 and the air inlet 2 are located on one side of the powder outlet, and the air inlet 1 and the air inlet 2 are connected to the mixing chamber. The oxygen-free copper powder enters the mixing chamber from the powder outlet, and the air inlet 1 and the air inlet 2 transport nitrogen into the mixing chamber from different directions, which reduces the dead angle of gas and powder mixing, improves the mixing efficiency, and ensures uniform airflow distribution during the mixing process.

[0014] The nozzle is made of stainless steel 304 or stainless steel 316L, and the roughness Ra of the inner wall of the nozzle is controlled at 0.08-0.15μm. The inner wall treatment not only helps to reduce the friction of the fluid inside the nozzle, thereby improving the uniformity and accuracy of the injection, but also effectively prolongs the service life of the nozzle, ensuring reliability and stability in various industrial applications.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The Laval nozzle of the present invention is designed with a powder particle uniform zone structure and a heating element to preheat the powder particles at the outlet, which is more helpful to increase the temperature and kinetic energy of the particles, thereby enhancing the spray uniformity performance and efficiency of the nozzle; wherein the powder particle uniform zone is designed for a specific application scenario, and the powder particle agglomeration phenomenon caused by the Coulomb force and the turbulence phenomenon generated by the high-speed airflow in the particle uniform zone are used to uniformly distribute the particles, thereby achieving the effect of uniformly dispersing the particles before acceleration. And a reasonable heating design can optimize the flow characteristics of the particles and improve the injection speed and uniformity of the nozzle; when the heated particles pass through the Laval nozzle, it is easier to reach the sonic or supersonic state, thereby enhancing the Laval effect. This helps to further improve the injection efficiency and thrust performance of the nozzle; and the integrated design with its own powder uniformity function can effectively reduce the equipment cost and facilitate the control of the distribution uniformity of the particle injection outlet.

[0017] 2. The present invention adopts an anti-blocking structure, through which high-pressure and high-speed gas and powder extrude the vibration cylinder, and cooperates with two springs above and below the vibration cylinder to produce a continuous vibration effect, thereby effectively preventing the blockage of the nozzle caused by oxygen-free copper powder due to long-term use of the nozzle. Under the premise of not affecting the spraying effect, it not only solves the problem of nozzle blockage and significantly extends the service life of the nozzle, but also further improves the stability and reliability of the spraying process.

[0018] 3. The present invention adopts a mixing structure, in which high-speed gas is blown into the air inlet to drive the baffle to rotate, and the baffle drives the scraper to continuously scrape off the oxygen-free copper powder on the inner wall and bottom of the mixing chamber, so that the powder in the mixing chamber is always evenly distributed, avoiding the accumulation and agglomeration of powder in the chamber, enhancing the mixing effect of powder and gas, and thus ensuring the uniform output of powder during the spraying process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A perspective view of the present invention;

[0020] Figure 2 is a cross-sectional view of a nozzle of the present invention;

[0021] Figure 3 It is a cross-sectional view of a mixing box and a vibration box of the present invention;

[0022] Figure 4 A three-dimensional diagram of the internal structure of the mixing box of the present invention;

[0023] Figure 5 It is a cross-sectional view of the internal structure of the vibration box of the present invention.

[0024] In the figure: 1. nozzle; 2. anti-blocking box; 3. mixing box; 4. powder outlet; 5. air inlet 1; 6. air inlet 2; 7. particle uniformity port; 8. particle uniformity chamber; 9. convergence pipe; 10. narrow mouth; 11. expansion pipe; 12. coolant chamber; 13. coolant inlet pipe; 14. coolant outlet pipe; 15. heating coil; 16. outlet; 17. protrusion; 18. sleeve; 19. vibrating cylinder; 20. spring 1; 21. spring 2; 22. baffle; 23. mixing chamber; 24. rotating shaft; 25. fixing ring 1; 26. fixing ring 2; 27. baffle 1; 28. scraper 1; 29. ​​baffle 2; 30. scraper 2. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1-Figure 5 The present invention provides a technical solution: a Laval nozzle device for uniform powder discharge, the nozzle device comprises a nozzle 1, an anti-blocking box 2 is installed on one side of the nozzle 1, a mixing box 3 is installed on one side of the anti-blocking box 2, and a powder outlet 4, an air inlet 1 5 and an air inlet 2 6 are installed on one side of the mixing box 3. The nozzle 1 adopts a Laval shape, which can form a low-pressure area under the action of high-speed airflow, so as to effectively suck in the powder and accelerate the injection. The structure inside the anti-blocking box 2 prevents the powder from accumulating and clogging in the box through vibration. The structure inside the mixing box 3 continuously mixes and stirs the gas and the powder to achieve a uniform mixing effect. The air inlet 1 5 and the air inlet 2 6 are respectively connected to independent gas sources. By accurately controlling the air intake volume and air intake speed, the dead angle in the process of gas entry can be effectively reduced, the contact area between the gas and the powder can be increased, and the mixing uniformity can be improved.

[0027] The nozzle 1 mainly includes a regional particle uniformity zone, a particle entry zone, a particle acceleration zone, a particle emission zone, a heating system and a cooling system. The particle uniformity zone includes a particle uniformity port 7 and a particle uniformity cavity 8. The particle uniformity port 7 is fixed inside the nozzle 1. The particle uniformity cavity 8 is located on one side of the particle uniformity port 7. The particle entry zone includes a convergence pipe 9. The convergence pipe 9 is located at the narrow mouth of the nozzle 1. The particle acceleration zone includes a narrow mouth 10 and an expansion pipe 11. The narrow mouth 10 is located on one side of the convergence pipe 9. The expansion pipe 11 is located on one side of the narrow mouth 10. The particle uniformity cavity 8, the narrow mouth 10 and the outlet 16 are located inside the nozzle 1. The particle uniformity port 7 is used to ensure that the particles can be preliminarily uniformly treated before entering the nozzle 1, which helps the particles to be more evenly distributed when passing through. The particle uniformity cavity 8 is used to further accelerate the particles to achieve the required injection speed. The convergence pipe 9 is used to further concentrate the particles to improve the accuracy and efficiency of the injection. The narrow mouth 10 is used to further control the shape and direction of the particle flow to ensure the stability and consistency of the particle flow during injection. The outlet 16 is used to ensure the smooth output of the particle flow.

[0028] The cooling system includes a coolant inlet pipe 13, a coolant chamber 12, and a coolant outlet pipe 14. The coolant chamber 12 is located inside the nozzle 1. The coolant inlet pipe 13 is located away from the expansion pipe 11, and the coolant outlet pipe 14 is located close to the expansion pipe 11. The coolant inlet pipe 13 and the coolant outlet pipe 14 are connected to the coolant chamber 12. The coolant enters the coolant chamber 12 from the coolant inlet pipe 13 and is discharged from the coolant outlet pipe 14. The coolant chamber 12 cools the outer shell of the nozzle 1 to reduce the size change of the nozzle 1 caused by thermal expansion.

[0029] The heating system is located in the emission area of ​​high-speed particles, and the heating system includes a heating coil 15. An annular groove is opened inside the nozzle 1, and the annular groove is located inside the coolant chamber 12. The heating coil 15 is installed in the annular groove, and the heating coil 15 is a spiral structure. The heating coil 15 heats the internal particles by transferring heat to the tube wall through the heating resistance wire, and preheats the powder particles at the outlet 16, which is more helpful to increase the temperature and kinetic energy of the particles, thereby enhancing the spraying uniformity performance and efficiency of the nozzle 1.

[0030] A cylindrical groove is provided inside the anti-blocking box 2, protrusions 17 are provided on both sides of the anti-blocking box 2, a sleeve 18 is installed in the groove, the sleeve 18 is fixed on the inner wall of the groove of the anti-blocking box 2, a vibration cylinder 19 is sleeved inside the sleeve 18, and multiple groups of inclined fences 22 are provided on the inner wall of the vibration cylinder 19, a protrusion is provided on one side of the vibration cylinder 19, and springs 1 20 and 21 are provided on both sides of the sleeve 18, the spring 1 20 is located on the side of the nozzle 1, and the spring 21 is located on the side of the mixing box 3. The groove structure is used to fix and support the internal components, the protrusion 17 increases the stability of the structure, and provides support for the spring 1 20 and the spring 2 21. When the vibration cylinder 19 is working, it vibrates under the drive of gas and powder, which helps to prevent material blockage. The spring 1 20 and the spring 2 21 are used to provide buffering for the vibration cylinder 19 when it is under pressure.

[0031] A mixing chamber 23 is provided inside the mixing box 3, and a rotating shaft 24 is provided inside the mixing chamber 23. The rotating shaft 24 is rotatably connected to the inner wall of the mixing box 3. A fixing ring 1 25 and two fixing rings 2 26 are installed on the rotating shaft 24. The fixing ring 1 25 is located in the middle of the rotating shaft 24. Baffles 1 27 are installed on both sides of the fixing ring 1 25, and a scraper 1 28 is installed on one side of the baffle 1 27. Fixing rings 26 are installed on both sides of the rotating shaft 24, baffles 29 are installed on both sides of the fixing ring 26, and a scraper 2 30 is installed on one side of the baffle 29. The mixing chamber 23 is used to contain and mix gas and powder. The rotating shaft 24 provides support for the mixing components. The function of baffles 1 27 and baffles 2 29 is to drive the rotating shaft 24 to rotate under the blowing of gas and powder, and also to play the role of stirring the mixed gas and powder. Scrapers 1 28 and scrapers 2 30 scrape the powder on the inner wall of the mixing chamber 23, improve the mixing efficiency, and ensure that the gas and powder can be fully mixed.

[0032] The powder outlet 4 is located at the center of one side of the mixing box 3, and the powder outlet 4 is connected to the mixing chamber 23. The air inlet 1 5 and the air inlet 2 6 are located on one side of the powder outlet 4, and the air inlet 1 5 and the air inlet 2 6 are connected to the mixing chamber 23. The oxygen-free copper powder enters the mixing chamber 23 from the powder outlet 4, and the air inlet 1 5 and the air inlet 2 6 transport nitrogen into the mixing chamber 23 from different directions, which reduces the dead angle of gas and powder mixing, improves the mixing efficiency, and ensures uniform airflow distribution during the mixing process.

[0033] The nozzle 1 is made of stainless steel 304 or stainless steel 316L, and the roughness Ra of the inner wall of the nozzle 1 is controlled at 0.08-0.15μm. The inner wall treatment not only helps to reduce the friction of the fluid inside the nozzle 1, thereby improving the uniformity and accuracy of the injection, but also effectively prolongs the service life of the nozzle 1, ensuring reliability and stability in various industrial applications.

[0034] Hereinafter, the present invention will be specifically described based on examples.

[0035] Example 1

[0036] A Laval nozzle device for uniform powder output

[0037] The AD spraying nozzle 1 used in this embodiment 1 is as follows Figure 2 The uniform powder discharging Laval nozzle device shown is made of stainless steel 316L material as a whole, and the inner wall surface roughness Ra of the particle uniform cavity 8, the convergent pipe 9, the narrow mouth 10, the expansion pipe 11, and the outlet 16 is 0.15μm, wherein the space area surrounded by the inner wall of the particle uniform port 7, the convergent pipe 9 and the expansion pipe 11 is roughly conical, the particle uniform cavity 8 has an inner diameter of 20mm and is connected to the convergent pipe 9, the length from the particle uniform cavity 8 to the narrow mouth 10 is 50mm, the inner diameters of the particle uniform port 7 and the narrow mouth 10 are both 3mm, the expansion pipe 11 is connected to the outlet 16, the inner diameter of the outlet 16 is 20mm, the connection length from the narrow mouth 10 to the outlet 16 is 120mm, and the overall wall thickness of the nozzle is 10mm; the coolant outlet pipe 14 and the coolant inlet pipe 13 are 5mm high, 3mm inner diameter, 2mm wall thickness, and communicate with the coolant chamber 12, and the heating coil 15 is made of Cr20Ni35.

[0038] In the embodiment, the above-mentioned Laval nozzle device for uniform powder discharge in the experiment is assembled in the AD spraying device, and the spraying operation is carried out. The operating conditions of the spraying device are as follows: nitrogen is used as the working gas, the working gas pressure of the particle uniformity chamber 8 is 2Mpa, oxygen-free copper powder with a particle size of 1-3μm is used in the raw material powder, the heating coil 15 is working for heating, the outlet temperature monitor monitors the particle outlet temperature of 345-352°C, the powder supply is 180g / min, the vacuum degree of the deposition chamber is 50Pa, and the spraying substrate is a 40*40mm high-purity aluminum plate.

[0039] Comparative Example 1

[0040] This comparative example adopts the nozzle 1 tested in the above-mentioned embodiment 1. While ensuring that the main accelerating structure size of the nozzle 1 is the same, a comparative spraying experiment is conducted. Nitrogen is used as the working gas, the working gas pressure of the particle uniformity chamber 8 is 2Mpa, oxygen-free copper powder with a particle size of 1-3μm is used in the raw material powder, the heating coil 15 is not heated, the outlet temperature monitor monitors the particle outlet temperature at 34-45°C, the powder supply is 180g / min, the vacuum degree of the deposition chamber is 50Pa, and the spraying substrate is a 40*40mm high-purity aluminum plate.

[0041] Performance test comparison:

[0042] Embodiment and Comparative Example After spraying the surface of the substrate aluminum plate, the performance of the film formed on the surface of the substrate was tested. The test comparison table is shown in the following table. It can be seen that the uniform powder discharge Laval nozzle designed by the present invention can effectively improve the quality of the film formed on the spraying surface, and the spraying efficiency is high;

[0043] Test comparison table

[0044] Example 1 Comparative Example 1 Film thickness 20-45μm 34-62μm Surface roughness Ra5.912μm Ra8.515μm Adhesion test No copper powder falling off Copper powder falls off Surface hardness 45-55HV 45-55HV Interface porosity 5-10％ 40-65％

[0045] The working principle of the present invention is as follows: before the nozzle device works, the control system controls the operation of the heating coil 15, and the heating coil 15 uses thermal radiation heat transfer to preheat the outlet 16. The control system controls the powder outlet 4 to input oxygen-free copper powder into the mixing chamber 23, and the air inlet 1 5 and the air inlet 2 6 input high-pressure and high-speed nitrogen into the mixing chamber 23 from different directions. The particle flow in the mixing chamber 23 pushes the baffle 1 27 and the baffle 2 29 to rotate around the rotating shaft 24. The baffle 1 27 and the baffle 2 29 drive the scraper 1 28 and the scraper 2 30 to rotate and scrape off the oxygen-free copper powder on the inner wall of the mixing chamber 23, so that the nitrogen in the mixing chamber 23 is fully mixed with the oxygen-free copper powder, avoiding the accumulation of oxygen-free copper powder at the bottom of the mixing chamber 23 to cause congestion, thereby improving the utilization rate of the material.

[0046] The particle flow enters the vibration cylinder 19 and drives the baffle 22 to move. The baffle 22 drives the vibration cylinder 19 to move toward the particle uniform port 7. The vibration cylinder 19 vibrates continuously under the action of the spring 1 20 and the spring 2 21 to prevent the blockage of the oxygen-free copper powder in the nozzle 1. The high-pressure particle flow is sprayed from the particle uniform port 7 to the particle uniform cavity 8. The turbulent powder particles in the particle uniform cavity 8 are fully dispersed and evenly distributed, and are accelerated into the narrow mouth 10 through the convergent pipe 9, and then sent to the outlet 16 through the expansion pipe 11. The particle flow velocity is relatively normal at the particle uniform cavity 8, and is close to the speed of sound through the convergent pipe 9 and the narrow mouth 10, and then reaches the maximum flow velocity at the expansion pipe 11 through the narrow mouth 10. The heating coil 15 heats the internal particles by transferring heat to the tube wall, and the outer ring coolant chamber 12 cools the outer shell of the nozzle 1. The coolant enters the coolant chamber 12 from the coolant inlet pipe 13 and is discharged from the coolant outlet pipe 14. The high-speed particles heated by the heating coil 15 are sent out from the outlet 16.

[0047] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A Laval nozzle device for uniform powder discharge, characterized in that: The nozzle device comprises a nozzle (1), an anti-blocking box (2) is installed on one side of the nozzle (1), a mixing box (3) is installed on one side of the anti-blocking box (2), and a powder outlet (4), an air inlet 1 (5) and an air inlet 2 (6) are installed on one side of the mixing box (3).

2. A Laval nozzle device for uniform powder discharge according to claim 1, characterized in that: The nozzle (1) mainly comprises a particle uniformity zone, a particle entry zone, a particle acceleration zone, a particle emission zone, a heating system and a cooling system. The particle uniformity zone comprises a particle uniformity port (7) and a particle uniformity cavity (8). The particle uniformity port (7) is arranged inside the nozzle (1). The particle uniformity cavity (8) is located on one side of the particle uniformity port (7). The particle entry zone comprises a convergent pipe (9). The convergent pipe (9) is located at the narrow mouth of the nozzle (1). The particle acceleration zone comprises a narrow mouth portion (10) and an expansion pipe (11). The narrow mouth portion (10) is located on one side of the convergent pipe (9). The expansion pipe (11) is located on one side of the narrow mouth portion (10). The particle emission zone comprises an outlet (16). The particle uniformity cavity (8), the narrow mouth portion (10) and the outlet (16) are located inside the nozzle (1).

3. A Laval nozzle device for uniform powder discharge according to claim 2, characterized in that: The cooling system comprises a coolant inlet pipe (13), a coolant chamber (12), and a coolant outlet pipe (14); the coolant chamber (12) is located inside the nozzle (1); the coolant inlet pipe (13) is located away from the expansion pipe (11); the coolant outlet pipe (14) is located close to the expansion pipe (11); and the coolant inlet pipe (13) and the coolant outlet pipe (14) are in communication with the coolant chamber (12).

4. A Laval nozzle device for uniform powder discharge according to claim 3, characterized in that: The heating system is located in the particle emission area, and the heating system comprises a heating coil (15). An annular groove is provided inside the nozzle (1), and the annular groove is located inside the cooling liquid chamber (12). The heating coil (15) is installed in the annular groove, and the heating coil (15) is a spiral structure.

5. A Laval nozzle device for uniform powder discharge according to claim 4, characterized in that: A cylindrical groove is arranged inside the anti-blocking box (2), protrusions (17) are arranged on both sides of the anti-blocking box (2), a sleeve (18) is installed in the groove, the sleeve (18) is fixed to the inner wall of the groove of the anti-blocking box (2), a vibration tube (19) is sleeved inside the sleeve (18), a plurality of groups of inclined baffles (22) are arranged on the inner wall of the vibration tube (19), a protrusion is arranged on one side of the vibration tube (19), a spring 1 (20) and a spring 2 (21) are arranged on both sides of the sleeve (18), the spring 1 (20) is located on one side of the nozzle (1), and the spring 2 (21) is located on one side of the mixing box (3).

6. A Laval nozzle device for uniform powder discharge according to claim 5, characterized in that: A mixing chamber (23) is arranged inside the mixing box (3), and a rotating shaft (24) is arranged inside the mixing chamber (23). The rotating shaft (24) is rotatably connected to the inner wall of the mixing box (3). A fixing ring 1 (25) and two fixing ring 2 (26) are mounted on the rotating shaft (24). The fixing ring 1 (25) is located in the middle of the rotating shaft (24). Baffle 1 (27) is mounted on both sides of the fixing ring 1 (25), and a scraper 1 (28) is mounted on one side of the baffle 1 (27). A fixing ring 2 (26) is mounted on both sides of the rotating shaft (24), and baffle 2 (29) is mounted on both sides of the fixing ring 2 (26), and a scraper 2 (30) is mounted on one side of the baffle 2 (29).

7. A Laval nozzle device for uniform powder discharge according to claim 6, characterized in that: The powder outlet (4) is located at the center of one side of the mixing box (3), and the powder outlet (4) is connected to the mixing chamber (23). The air inlet 1 (5) and the air inlet 2 (6) are located on one side of the powder outlet (4), and the air inlet 1 (5) and the air inlet 2 (6) are connected to the mixing chamber (23).

8. A Laval nozzle device for uniform powder discharge according to claim 7, characterized in that: The nozzle (1) is made of stainless steel 304 or stainless steel 316L, and the roughness Ra of the inner wall of the nozzle (1) is controlled within a range of 0.08-0.15 μm.

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