Powder mixing and conveying device

Abstract

The invention relates to the field of mixing machines, and particularly discloses a powder mixing and conveying device which comprises a base, a powder premixing mechanism, a powder mixing mechanism and a bidirectional stirring mechanism, and the powder premixing mechanism is arranged on the base and used for premixing multiple kinds of powder; the powder mixing mechanism is arranged on the base and connected to the discharging end of the powder premixing mechanism, the powder mixing mechanism comprises a cylindrical mixing tank which is rotationally arranged, the axis of the mixing tank is obliquely arranged, and the rotating axis of the mixing tank is horizontally arranged; the two-way stirring mechanism comprises two stirring paddles rotationally arranged in the mixing tank, the two stirring paddles are coaxially arranged, the rotating directions of the two stirring paddles are opposite, and the rotating axes of the stirring paddles are collinear with the axis of the mixing tank. The mixing tank and the stirring paddle rotate synchronously, and the rotating axes of the mixing tank and the stirring paddle are not collinear, so that uniform mixing of the powder is facilitated, and synchronous mixing and conveying of the powder can be realized.

Description

Technical Field

[0001] The present application relates to the field of mixers, and in particular to a powder mixing and conveying device. Background Art

[0002] Laser cladding, an advanced surface modification technology, forms a metallurgically bonded, high-performance coating on a substrate through the interaction of a high-energy laser beam and synchronously conveyed metal powder. It has important applications in aerospace, mold repair, and other fields. Uniform mixing and stable delivery of multi-component powders are key process steps that influence the uniformity of the cladding layer's structure, interfacial bonding strength, and defect control.

[0003] Existing technologies typically combine pre-mixing with separate conveying. This involves pre-mixing the powders in a mechanical mixing tank or drum-type mixing equipment, and then transferring the mixed powders to the cladding nozzle via a pneumatic conveying system. This separation of mixing and conveying results in a large equipment footprint and long process cycles, making it difficult to adapt to continuous production requirements. Furthermore, during the mixing process, powders of varying densities and particle sizes segregate due to gravity settling, which can affect the performance of the cladding layer. Summary of the Invention

[0004] In view of the shortcomings of the existing technology that combines pre-mixing with split-type conveying, the present application provides a powder mixing and conveying device.

[0005] The present application provides a powder mixing and conveying device that adopts the following technical solution: A powder mixing and conveying device, comprising: base; A powder premixing mechanism is provided on the base and is used for premixing a plurality of powders; a powder mixing mechanism, disposed on the base and connected to the discharge end of the powder premixing mechanism, the powder mixing mechanism comprising a rotatably arranged mixing tank, the mixing tank being cylindrical, with its axis being inclined and its rotation axis being horizontally arranged; The bidirectional stirring mechanism includes two stirring paddles rotatably arranged in the mixing tank, the two stirring paddles are coaxially arranged and rotate in opposite directions, and the rotation axis of the stirring paddles is collinear with the axis of the mixing tank.

[0006] In conventional drum-type mixing devices, the axis of the drum coincides with the axis of rotation, and both are vertical or horizontal. The powder's motion trajectory in the drum is simple, and it only moves in a circular motion. In the present application, the mixing tank is tilted and rotates around a horizontal axis. The tilted drum wall causes the powder to be simultaneously subjected to the coupling effects of the tangential component of gravity and the radial component of centrifugal force. The motion trajectory of the powder in the tank is more complex, that is, it moves in both the axial and radial directions of the mixing tank, thereby increasing the uniformity of the mixing. The shearing and mixing effects of the bidirectional stirring mechanism further promote uniform mixing of the powder, especially for powders of different densities or particle sizes, to prevent stratification.

[0007] Furthermore, a feed end fixing seat is fixedly provided on the base, a feed port is provided on the feed end fixing seat, and the feed port is connected to the discharge end of the powder premixing mechanism; a feed pipe is rotatably provided on the feed end fixing seat, one end of the feed pipe is connected to the feed port, and the other end is located in the mixing tank.

[0008] Furthermore, the feed pipe is fixedly connected to the mixing tank, and the axis of the feed pipe is collinear with the rotation axis of the mixing tank.

[0009] The powder mixed by the powder premixing mechanism passes through the feed port and the feed pipe in sequence and is fed into the mixing tank for further mixing.

[0010] Furthermore, the discharge end of the mixing tank is provided with an annular feeding pipe, which is fixedly connected to the inner wall of the mixing tank and is coaxial with the mixing tank; the annular feeding pipe is provided with multiple feeding holes on the side facing the feed end of the mixing tank.

[0011] Furthermore, the annular feeding pipe is fixedly connected to the discharge pipe and the two are connected, the axis of the discharge pipe is colinear with the rotation axis of the mixing tank, and a driving component for driving the discharge pipe to rotate is provided on the base.

[0012] As the mixing tank rotates about its horizontal axis, the annular feed tube rotates synchronously with the mixing tank. When the side of the annular feed tube with the feed hole tilts upward, the powder in the mixing tank enters the annular feed tube through the feed hole under the action of its own gravity and is then discharged through the discharge tube, achieving simultaneous mixing and conveying of the powder. Due to the inclined setting of the annular feed tube, the discharge of the powder is intermittent. With each rotation of the mixing tank, the powder is fully mixed, enters the annular feed tube, and is discharged through the discharge tube.

[0013] Furthermore, the angle between the axis of the mixing tank and its own rotation axis is 15°-30°.

[0014] When the inclination angle is less than 15°, the tangential component of gravity along the tank wall is too small, making it difficult for the powder to break through static friction and form a continuous spiral climb, causing the mixing mode to degenerate into a near-two-dimensional diffusion mode. When the inclination angle is greater than 30°, the normal component of the centrifugal force becomes too large, causing the powder to prematurely break away from the tank wall and form a free fall, disrupting the continuity of the flow field. At an inclination angle of 15°-30°, the axial velocity component and the radial shear rate are optimally matched, causing the powder to undergo a compound motion cycle of spiral climb (axial diffusion), parabolic scattering (radial shear), and impact with the agitator paddles (turbulent breakup), resulting in a better mixing effect.

[0015] Furthermore, the bidirectional stirring mechanism includes an input shaft and a first sleeve and a second sleeve sleeved on the input shaft, the first sleeve is coaxially fixed to the input shaft, the second sleeve is rotatably connected to the input shaft, and the two stirring paddles are respectively fixed to the first sleeve and the second sleeve; the bidirectional stirring mechanism also includes a planetary gear drive assembly for driving the input shaft and the second sleeve to rotate synchronously in opposite directions.

[0016] Furthermore, the planetary gear drive assembly includes a rotatable inner ring gear and a planet carrier, three planetary gears are rotatably arranged on the planet carrier, the three planetary gears are engaged with the inner ring gear, and the three planetary gears are commonly engaged with a sun gear; the sun gear is coaxially fixed to the input shaft, and the inner ring gear is coaxially fixed to the second sleeve; the planetary gear drive assembly also includes a driving member for driving the input shaft to rotate.

[0017] Furthermore, the first sleeve and the second sleeve are respectively located in the mixing tank near the discharge end and the feed end.

[0018] Furthermore, each stirring paddle includes a plurality of spiral-shaped stirring blades, and a stirring fan frame and a blade holder are fixedly connected to the first sleeve and the second sleeve, and two ends of the stirring blade are respectively fixed to the stirring fan frame and the blade holder.

[0019] When the driving member drives the input shaft to rotate, the inner ring gear rotates under the transmission of the sun gear and the planetary gear, and the rotation direction of the input shaft and the inner ring gear is opposite, realizing the synchronous reverse rotation of the first sleeve and the second sleeve. In this way, the two stirring paddles rotate synchronously in the opposite direction, which is beneficial to improve the stirring effect.

[0020] On the other hand, the rotation speed of the sun gear is greater than the rotation speed of the inner ring gear, so that the rotation speed of the first sleeve is greater than the rotation speed of the second sleeve, that is, the rotation speed of the stirring paddle at the discharge end of the mixing tank is greater than the rotation speed of the stirring paddle at the feed end of the mixing tank; the feeding end of the mixing tank stirs at a low speed to reduce the initial kinetic energy of the powder and avoid fine powder dust, while maintaining a sufficient shear rate to achieve coarse mixing; the discharge end of the mixing tank stirs in reverse at a high speed to produce a strong turbulent zone, which effectively breaks up the powder agglomerates at the conveying end, and the pressure pulsation generated by the high-speed stirring and the centrifugal compaction field formed by the rotation of the inclined mixing tank offset each other, thereby suppressing powder stratification; the axial speed difference formed by the speed gradient is used to drive the powder to form a directional migration flow, thereby shortening the mixing cycle.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. This application adopts an inclined mixing tank that rotates around a horizontal axis, which improves the single movement trajectory of powder in conventional drum-type mixing devices and increases mixing uniformity; 2. By adopting a bidirectional stirring mechanism, coarse mixing is achieved at the feeding end of the mixing tank, and powder agglomerates are effectively broken up and powder stratification is suppressed at the discharging end of the mixing tank, further improving the mixing uniformity; 3. The present application can realize the simultaneous mixing and conveying of powder materials, thereby improving the problem in traditional devices where the separation of the mixing and conveying processes results in a large equipment footprint and a long process cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application; Figure 2 It is a schematic diagram mainly used to illustrate the structure of the mixing tank in the embodiment of the present application; Figure 3 It is along Figure 2 Schematic diagram of the cross-sectional structure along line AA; Figure 4 This is a schematic diagram mainly used to illustrate the structure of the annular feeding pipe and the discharging pipe in the embodiment of the present application; Figure 5 This is a schematic diagram of the structure of the bidirectional stirring mechanism in the embodiment of the present application; Figure 6 It is a structural schematic diagram mainly used to show the planetary gear drive assembly in the embodiment of the present application, wherein (a) is an overall view and (b) is a cross-sectional view.

[0023] Figure markings: 1. base; 2. powder premixing mechanism; 21. metal powder storage tank; 22. powder conveying device; 23. first feed pipe; 24. pneumatic conveying premixing device; 25. second feed pipe; 26. third feed pipe; 3. powder mixing mechanism; 31. mixing tank; 32. feed end fixing seat; 321. feed port; 33. feed pipe; 34. annular feed pipe; 341. feed hole; 35. discharge pipe; 36. first motor; 37. reduction gear; 4. two-way stirring mechanism; 41. input shaft; 42. first sleeve; 43. second sleeve; 44. planetary gear drive assembly; 441. inner ring gear; 442. planetary carrier; 443. planetary gear; 444. sun gear; 45. stirring paddle; 451. stirring blade; 452. stirring fan frame; 453. blade retaining frame; 46. second motor. DETAILED DESCRIPTION

[0024] The following is combined with Figure 1-6 This application is described in further detail.

[0025] The embodiment of the present application discloses a powder mixing and conveying device. Figure 1 and Figure 2 The powder mixing and conveying device includes a base 1, a powder premixing mechanism 2, and a powder mixing mechanism 3 mounted on the base 1. The powder premixing mechanism 2 is used to premix multiple powders. The powder mixing mechanism 3 is connected to the discharge end of the powder premixing mechanism 2 and includes a rotating mixing tank 31. The mixing tank 31 is cylindrical, with its axis tilted and its rotation axis horizontal. The angle between the axis of the mixing tank 31 and its own rotation axis is 15°-30°. A bidirectional stirring mechanism 4 is disposed within the mixing tank 31.

[0026] Reference Figure 1 The powder premixing mechanism 2 includes multiple metal powder storage tanks 21, each for storing different types of metal powder. A powder conveying device 22 is mounted at the discharge end of each metal powder storage tank 21. The discharge end of the powder conveying device 22 is connected to a first conveying pipe 23. The multiple first conveying pipes 23 are collectively connected to a second conveying pipe 25. The second conveying pipe 25 is sequentially connected to a pneumatic conveying premixing device 24 and a third conveying pipe 26 along the powder conveying direction.

[0027] Different types of metal powder are output by the corresponding powder conveying device 22, pass through the first conveying pipe 23 and the second conveying pipe 25 in sequence, and enter the pneumatic conveying premixing device 24 for premixing. The premixed powder is conveyed to the mixing tank 31 by the third conveying pipe 26 for further mixing.

[0028] Reference Figure 2 and Figure 3A feed end mounting base 32 is fixedly mounted on the base 1. A feed port 321 is provided on the mounting base 32. The feed port 321 is connected to the discharge end of the powder premixing mechanism 2 (i.e., the third feed pipe 26). A feed pipe 33 is rotatably connected to the mounting base 32 via a bearing. One end of the feed pipe 33 is connected to the feed port 321, and the other end extends into the mixing tank 31. The feed pipe 33 is fixedly connected to the mixing tank 31. The feed pipe 33 is horizontally arranged, with its axis collinear with the rotation axis of the mixing tank 31.

[0029] Reference Figure 3 and Figure 4 The discharge end of the mixing tank 31 is provided with an annular feed pipe 34, which is fixedly connected to the mixing tank 31. The annular feed pipe 34 is arranged at an angle and is coaxial with the mixing tank 31. Furthermore, a plurality of feed holes 341 are formed on the side of the annular feed pipe 34 facing the feed end of the mixing tank 31. The annular feed pipe 34 is connected to a discharge pipe 35 via a hollow pipe, and the annular feed pipe 34 is in communication with the discharge pipe 35. The discharge pipe 35 is arranged horizontally, and its axis is colinear with the rotation axis of the mixing tank 31; the discharge pipe 35 is fixedly connected to the mixing tank 31.

[0030] Reference Figure 4 A driving assembly for driving the discharge pipe 35 to rotate is provided on the base 1. Specifically, the driving assembly includes a first motor 36 fixedly provided on the base 1 and a reduction gear box 37 installed at the output end of the first motor 36. The output end of the reduction gear box 37 is fixedly connected to the discharge pipe 35.

[0031] The discharge pipe 35 is driven to rotate by the first motor 36, and the inclined mixing tank 31 rotates around the horizontal axis. The inclined cylinder wall causes the powder to be simultaneously subjected to the coupling effect of the tangential component of gravity and the radial component of centrifugal force. The movement trajectory of the powder in the tank is more complicated than that of a conventional drum-type mixing device. The powder moves in both the axial and radial directions of the mixing tank 31, thereby increasing the uniformity of mixing.

[0032] During the rotation of the mixing tank 31 around the horizontal axis, the inclined annular feed pipe 34 rotates synchronously with the mixing tank 31. When the side of the annular feed pipe 34 with the feed hole 341 is rotated to face upward, the powder in the mixing tank 31 enters the annular feed pipe 34 through the feed hole 341 under the action of its own gravity and the air pressure of the pneumatic conveying premixing device 24, and is then discharged through the discharge pipe 35, thereby achieving simultaneous mixing and conveying of the powder.

[0033] Reference Figure 5 and Figure 6The bidirectional stirring mechanism 4 includes two stirring paddles 45 rotatably disposed within the mixing tank 31. The two stirring paddles 45 are coaxially disposed and rotate in opposite directions. The rotation axes of the stirring paddles 45 are collinear with the axis of the mixing tank 31. The bidirectional stirring mechanism 4 also includes an input shaft 41, a first sleeve 42, a second sleeve 43, and a planetary gear drive assembly 44. The first sleeve 42 is sleeved on the input shaft 41 and coaxially fixed to the input shaft 41. The second sleeve 43 is sleeved on the input shaft 41 and rotatably connected to the input shaft 41 via a bearing. The two stirring paddles 45 are respectively fixed to the first sleeve 42 and the second sleeve 43. The planetary gear drive assembly 44 is used to drive the input shaft 41 and the second sleeve 43 to rotate synchronously in opposite directions.

[0034] Further, refer to Figure 5 and Figure 6 The planetary gear drive assembly 44 includes a rotatable inner ring gear 441 and a planet carrier 442. Three planetary gears 443 are rotatably mounted on the planet carrier 442. These three planetary gears 443 mesh with the inner ring gear 441, and all three planetary gears 443 mesh with a sun gear 444. Sun gear 444 is coaxially fixed to the input shaft 41, and the inner ring gear 441 is coaxially fixed to the second sleeve 43. The planetary gear drive assembly 44 also includes a driving member for rotating the input shaft 41, which is a second motor 46.

[0035] Reference Figure 2 and Figure 5 The first sleeve 42 and the second sleeve 43 are respectively located in the mixing tank 31 near the discharge end and the feed end.

[0036] Reference Figure 5 Each stirring paddle 45 includes at least three spiral-shaped stirring blades 451. The first sleeve 42 and the second sleeve 43 are fixedly connected to a stirring fan frame 452 and a blade holder 453. The two ends of the stirring blade 451 are respectively fixed to the stirring fan frame 452 and the blade holder 453.

[0037] When the second motor 46 drives the input shaft 41 to rotate, the inner ring gear 441 rotates under the drive of the sun gear 444 and the planetary gear 443, and the rotation direction of the input shaft 41 is opposite to that of the inner ring gear 441, thereby realizing the synchronous reverse rotation of the first sleeve 42 and the second sleeve 43. In this way, the two stirring paddles 45 rotate synchronously in the opposite direction, which is beneficial to improving the stirring effect.

[0038] On the other hand, the rotation speed of the sun gear 444 is greater than that of the inner ring gear 441, which causes the rotation speed of the first sleeve 42 to be greater than that of the second sleeve 43. That is, the rotation speed of the stirring paddle 45 at the discharge end of the mixing tank 31 is greater than the rotation speed of the stirring paddle 45 at the feed end of the mixing tank 31. The low-speed stirring at the feed end of the mixing tank 31 reduces the initial kinetic energy of the powder and prevents fine powder from raising dust, while maintaining a sufficient shear rate for coarse mixing. The high-speed reverse stirring at the discharge end of the mixing tank 31 creates a strong turbulent flow zone, effectively breaking up powder agglomerates at the conveying end. The pressure pulsation generated by the high-speed stirring and the centrifugal compaction field formed by the rotation of the tilted mixing tank 31 offset each other, suppressing powder stratification. The axial velocity difference formed by the speed gradient is used to drive the powder into a directional migration flow, shortening the mixing cycle.

[0039] The mixing tank 31 rotates around the horizontal axis and cooperates with the shearing and mixing action of the bidirectional stirring mechanism 4, so that the powder undergoes a compound motion cycle of spiral climbing (axial diffusion), parabolic scattering (radial shearing), and impacting the stirring paddle 45 (turbulent crushing), thereby achieving a better mixing effect.

[0040] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A powder mixing and conveying device, characterized in that: include: base; A powder premixing mechanism is provided on the base and is used for premixing a plurality of powders; a powder mixing mechanism, disposed on the base and connected to the discharge end of the powder premixing mechanism, the powder mixing mechanism comprising a rotatably arranged mixing tank, the mixing tank being cylindrical, with its axis being inclined and its rotation axis being horizontally arranged; The bidirectional stirring mechanism includes two stirring paddles rotatably arranged in the mixing tank, the two stirring paddles are coaxially arranged and rotate in opposite directions, and the rotation axis of the stirring paddles is collinear with the axis of the mixing tank.

2. A powder mixing and conveying device according to claim 1, characterized in that: A feed end fixing seat is fixedly provided on the base, a feed port is provided on the feed end fixing seat, and the feed port is connected to the discharge end of the powder premixing mechanism; a feed pipe is rotatably provided on the feed end fixing seat, one end of the feed pipe is connected to the feed port, and the other end is located in the mixing tank.

3. A powder mixing and conveying device according to claim 2, characterized in that: The feed pipe is fixedly connected to the mixing tank, and the axis of the feed pipe is collinear with the rotation axis of the mixing tank.

4. A powder mixing and conveying device according to claim 3, characterized in that: The discharge end of the mixing tank is provided with an annular feeding pipe, which is fixedly connected to the inner wall of the mixing tank and is coaxial with the mixing tank; a plurality of feeding holes are opened on the side of the annular feeding pipe facing the feed end of the mixing tank.

5. A powder mixing and conveying device according to claim 4, characterized in that: The annular feeding pipe is fixedly connected to the discharge pipe and the two are communicated. The axis of the discharge pipe is colinear with the rotation axis of the mixing tank. A driving component for driving the discharge pipe to rotate is provided on the base.

6. A powder mixing and conveying device according to any one of claims 1 to 5, characterized in that: The angle between the axis of the mixing tank and its own rotation axis is 15°-30°.

7. The powder mixing and conveying device according to claim 1, characterized in that: The bidirectional stirring mechanism includes an input shaft and a first sleeve and a second sleeve sleeved on the input shaft, the first sleeve is coaxially fixed to the input shaft, the second sleeve is rotatably connected to the input shaft, and the two stirring paddles are respectively fixed to the first sleeve and the second sleeve; the bidirectional stirring mechanism also includes a planetary gear drive assembly for driving the input shaft and the second sleeve to rotate synchronously in opposite directions.

8. The powder mixing and conveying device according to claim 7, characterized in that: The planetary gear drive assembly includes a rotatable inner ring gear and a planet carrier, three planetary gears are rotatably mounted on the planet carrier, the three planetary gears are meshed with the inner ring gear, and the three planetary gears are commonly meshed with a sun gear; the sun gear is coaxially fixed to the input shaft, and the inner ring gear is coaxially fixed to the second sleeve; the planetary gear drive assembly also includes a driving member for driving the input shaft to rotate.

9. The powder mixing and conveying device according to claim 8, characterized in that: The first sleeve and the second sleeve are respectively located in the mixing tank near the discharge end and the feed end.

10. The powder mixing and conveying device according to claim 9, characterized in that: Each stirring paddle includes a plurality of spiral-shaped stirring blades. The first sleeve and the second sleeve are both fixedly connected to a stirring fan frame and a blade holder. The two ends of the stirring blade are respectively fixed to the stirring fan frame and the blade holder.

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