A mixer for mixing granular substances having a large difference in density

Abstract

The utility model relates to a kind of mixing machine for mixing granular material with big density difference, belong to mixing machine technical field, to solve the low uniformity of traditional equipment mixing, poor efficiency, dead angle and difficult dispersion lump problem etc. The mixing machine includes mixing cavity, main shaft, agitator, wall scraper and pneumatic auxiliary device, agitator has adopted the first and second agitator combination of different size, axial stagger and circumferential uniform arrangement, forms multiple intensity flow field, effectively suppresses the material layering caused by density difference;Agitator paddle adopts the multilayer variable-angle design of different size, improves mixing intensity and efficiency;Wall scraper is set at the both ends of main shaft, can continuously remove cavity wall attachment, eliminate mixing dead angle;Main shaft is integrated with air path inside, through micro-hole intermittent air injection, dispersed material is scattered by mechanical force. The utility model can be used for mixing powder or granular material with big density difference.

Description

Technical Field

[0001] This application relates to the field of mixer technology, and more specifically to a mixer for mixing particulate materials with large density differences. Background Technology

[0002] In existing technologies, processes for mixing particulate materials typically rely on conventional mixing machines. The core component of these machines is a single-structure mixing shaft equipped with standard impeller blades or a spiral ribbon. While they perform well when handling single or similarly composed materials, these conventional mixers reveal the following key problems when dealing with particulate materials composed of multiple components with significantly different densities (such as rare earth flame retardant raw materials):

[0003] 1. Limited Mixing Uniformity: When mixers process raw materials containing both light and heavy components, the design of conventional stirring elements often leads to severe material stratification. Heavy components tend to accumulate at the bottom and periphery of the mixing container, while light components tend to float to the center or top. This physical stratification reduces mixing uniformity, thus affecting the performance consistency of the final flame retardant product.

[0004] 2. Low mixing efficiency: Due to the single structure of the stirring element, it cannot flexibly adjust the mixing intensity and mode according to the density characteristics of the materials. This means that when processing materials with large density differences, either the stirring element applies excessively high intensity to all materials, leading to energy waste and equipment wear, or the force is insufficient to overcome the centrifugal tendency of heavy materials, resulting in incomplete mixing.

[0005] 3. Mixing dead zone problem: In the design of traditional mixers, it is very common for materials to accumulate in certain corners, especially when there are large density differences between material components. This not only limits the mixing efficiency, but may also lead to the presence of unmixed lumps or strips in the mixture, causing trouble for subsequent processing.

[0006] 4. Difficult to handle materials that are prone to clumping: For some light and fine powders that are easy to adsorb and clump together, traditional mechanical mixing methods often fail to achieve the desired dispersion effect. Even if the mixing time is extended, these clumps cannot be effectively broken up, which seriously affects the mixing quality.

[0007] In summary, existing mixers suffer from low mixing uniformity, low efficiency, dead zones, and difficulty in fully dispersing easily agglomerated materials when processing particulate materials with large density differences. To address these challenges, a novel mixer is needed that can provide differentiated mixing strategies for materials of varying densities, while also eliminating dead zones and effectively dispersing small clumps. This invention addresses this need by employing innovative spindle and stirring element designs to provide a more efficient and uniform mixing solution. Utility Model Content

[0008] Based on the above analysis, the present invention aims to provide a mixer for mixing particulate materials with large density differences, in order to solve one of the problems of low mixing uniformity, low mixing efficiency, dead corners, and difficulty in fully dispersing easily agglomerated materials when mixing particulate materials with large density differences in the prior art.

[0009] The objective of this utility model is mainly achieved through the following technical solutions:

[0010] A mixer for mixing particulate materials with large density differences includes: a mixing chamber, a main shaft, an agitator, and a wall scraper;

[0011] Both the agitator and the scraper are enclosed within the mixing chamber and are fixed to the main shaft and rotate with it.

[0012] The agitator is a paddle agitator, including a first agitator and a second agitator, wherein the length of the second agitator along the radial direction of the main shaft is 0.5-0.8 times the length of the first agitator along the radial direction of the main shaft;

[0013] The number of the first stirrers is not less than 4, two of which are located at the left and right ends of the main shaft and are arranged opposite each other at a 180-degree angle, and the rest are evenly staggered in the middle part of the main shaft. All the first stirrers are evenly staggered in the circumference of the main shaft.

[0014] The number of second stirrers is twice the number of first stirrers, and they are evenly arranged on the main shaft along the axial direction and are all staggered from the axial direction of the first stirrers. All the second stirrers are evenly staggered along the circumference of the main shaft.

[0015] The scraper is used to remove material adhering to the end wall and peripheral wall of the mixing chamber.

[0016] Furthermore, the first agitator includes a first support base, a first support shaft, a first inner layer blade, and a first outer layer blade. The first support base is fixedly connected to the main shaft, and the first support shaft and the first support base are threadedly connected. There are three first inner layer blades, which are sequentially fixedly connected to the first support shaft along the axial direction of the first support shaft. The first outer layer blade is fixedly connected to the outer end of the first support shaft.

[0017] Furthermore, the angles between the three first inner blades and the first support shaft, as well as the angle between the first outer blade and the first support shaft, are all different; the sizes of the first inner blades and the first outer blades are also different, with the blades on the outermost side being larger in the radial direction along the main shaft.

[0018] Furthermore, the second agitator includes a second support base, a second support shaft, a second inner layer blade, and a second outer layer blade. The second support base is fixedly connected to the main shaft, and the second support shaft and the second support base are threadedly connected. There are three second inner layer blades, which are sequentially fixedly connected to the second support shaft along the axial direction of the second support shaft. The second outer layer blade is fixedly connected to the outer end of the second support shaft.

[0019] Furthermore, the angles between the three second inner blades and the second support shaft, and the angles between the second outer blades and the second support shaft are all different.

[0020] Furthermore, the second inner blade and the second outer blade are also different in size, with the outermost blade being larger in size along the radial direction of the main shaft.

[0021] Furthermore, there are two scrapers, which are respectively located at the left and right ends of the main shaft, and the two scrapers located at the left and right ends of the main shaft are arranged 180 degrees opposite each other.

[0022] Furthermore, the wall scraper includes a scraper support rod and a scraper. The scraper support rod is perpendicular to the axis of the main shaft and is fixedly connected to the main shaft. The scraper is detachably and fixedly connected to the scraper arm support rod.

[0023] Furthermore, the scraper has a planar structure, with a straight edge near the end of the mixing chamber and a rounded edge near the peripheral wall of the mixing chamber. The straight edge of the scraper is 5-8 mm away from the inner wall of the end of the mixing chamber, and the outermost edge of the rounded edge of the scraper is 5-8 mm away from the peripheral wall of the mixing chamber.

[0024] Furthermore, the mixer also includes a pneumatically assisted mixing device. The main shaft is a hollow structure, and an auxiliary airflow channel is provided inside the main shaft. Microholes communicating with the auxiliary airflow channel are opened on the side wall of the main shaft. One end of the main shaft is connected to a controllable air source. The auxiliary airflow channel, the microholes, and the controllable air source together constitute the pneumatically assisted mixing device.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] 1. It effectively suppresses material stratification and achieves three-dimensional uniform mixing.

[0027] The large-sized primary agitator mainly operates in the periphery and bottom of the mixing chamber, generating strong radial and axial flows that effectively move and lift denser materials, preventing their sedimentation. The number of smaller secondary agitators is multiplied and densely distributed along the main shaft, primarily enhancing material exchange in the central region and between layers, preventing lighter materials from floating and agglomerating. This arrangement creates strong convection, shearing, and diffusion effects, forcing significantly different density components (light and heavy) to continuously exchange positions throughout the chamber, fundamentally overcoming material stratification caused by density differences and significantly improving mixing uniformity.

[0028] 2. The multi-stage, variable-angle blade design ensures appropriate mixing intensity and doubles efficiency in the mixing process.

[0029] Both the first and second agitators employ a multi-layered blade structure (inner blade + outer blade), with each layer of blades having a different angle with the support shaft. The blades closer to the main shaft on the radially outer side are larger. This design allows a single agitator to simultaneously apply a combination of forces in different directions (such as deflection, diversion, lifting, and shearing) to the material during rotation, achieving high-intensity and high-efficiency mixing without increasing the main shaft speed. Compared to traditional single-structure agitators, this invention achieves the preset mixing uniformity standard in a shorter time, thereby reducing energy consumption and increasing equipment processing capacity.

[0030] 3. The special scraper design ensures the cleanliness of the mixing chamber end walls and peripheral walls, completely eliminating mixing dead zones.

[0031] The scrapers, positioned at both ends of the main shaft and arranged 180 degrees apart, precisely match the straight and curved edges of their scrapers to the end and peripheral walls of the mixing chamber, maintaining a constant gap of 5-8mm. As the main shaft rotates, the scrapers continuously remove material adhering to the walls, allowing it to re-enter the main mixing zone for further circulation. This active cleaning mechanism effectively prevents material accumulation and retention in corners, ensuring that all materials, especially lightweight fine powders prone to sticking to the walls, are thoroughly mixed.

[0032] 4. The combination of mechanical stirring and pneumatic assistance can effectively break up soft lumps and internally compacted lumps formed by light and fine powders, achieving efficient dispersion of lumps through the synergy of mechanical and pneumatic forces.

[0033] On the one hand, the strong shearing and turbulence generated by the multi-layered variable-angle blades break up most of the clumps. On the other hand, the innovative pneumatic-assisted mixing device intermittently injects airflow into the material pile through airflow channels and micropores within the main shaft. This airflow is flexible and penetrating, able to penetrate into the interior of the material that is difficult for mechanical agitation to reach, "blowing away" or "loosening" the clumps from the inside. This "rigid-flexible" mixing method is particularly suitable for solving the technical problem of easy adsorption and agglomeration of lightweight, fine components in granular raw materials, achieving a more thorough dispersion effect.

[0034] In summary, this invention, through the synergistic effect of a differentially arranged composite agitator, multi-layered variable-angle blades, an active wall scraping mechanism, and a pneumatically assisted dispersion device, forms a three-dimensional, multi-mechanism mixing solution. It not only significantly improves the mixing uniformity and efficiency of complex materials such as rare earth flame retardants with large density differences and a tendency to agglomerate, but also effectively eliminates mixing dead zones, ensuring batch-to-batch consistency and stability, demonstrating outstanding practicality and technological advancement.

[0035] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing this invention. The objectives and other advantages of this invention can be realized and obtained through the details specifically pointed out in the text and accompanying drawings. Attached Figure Description

[0036] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0037] Figure 1 This is a schematic diagram of the main shaft, agitator, and wall scraper of a mixer for mixing granular materials with large density differences, according to a specific embodiment.

[0038] Figure label:

[0039] 1-Main shaft; 2-Agitator; 21-First agitator; 211-First support base; 212-First support shaft; 213-First inner layer blade; 214-First outer layer blade; 22-Second agitator; 221-Second support base; 222-Second support shaft; 223-Second inner layer blade; 224-Second outer layer blade; 3-Wall scraper; 31-Scraper support rod; 32-Scraper; 321-Straight edge of scraper; 322-Rounded edge of scraper. Detailed Implementation

[0040] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0041] A specific embodiment of this utility model discloses a mixer for mixing particulate materials with large density differences. For example... Figure 1 As shown, the mixer includes a mixing chamber, a main shaft 1, a stirrer 2, a wall scraper 3, and a pneumatic auxiliary mixing device.

[0042] Furthermore, the mixer also includes a motor drive unit, which serves as the power source for the mixer and drives the main shaft 1 to rotate. The upper part of the mixing chamber is semi-cylindrical, and its bottom is ω-shaped or conical, with a discharge valve located at the center of the bottom. This structure facilitates the full flow and complete discharge of materials. The agitator 2 and the scraper 3 are both fixedly connected to the main shaft 1 and move within the mixing chamber as the main shaft 1 rotates.

[0043] The agitator 2 includes a first agitator 21 and a second agitator 22. The maximum radial length of the first agitator 21 along the main shaft 1 is 0.8-0.9 times the radius of the upper semi-cylinder of the mixing chamber. The maximum radial length of the second agitator 22 along the main shaft 1 is 0.5-0.8 times the maximum radial length of the first agitator 21 along the main shaft 1. There are at least four first agitators 21, with two located at the left and right ends of the main shaft 1, facing each other at a 180-degree angle. The remaining first agitators 21 are located in the middle of the main shaft 1 and are evenly staggered along the axial direction of the main shaft 1. Furthermore, all first agitators 21 are staggered circumferentially along the main shaft 1, and the angle between adjacent first agitators 21 is the same, ranging from 90 to 180 degrees. The number of second agitators 22 is twice the number of first agitators 21. They are evenly arranged on the main shaft 1 and staggered from the first agitators 21 along the axial direction of the main shaft 1. All the second stirrers 22 are also staggered around the main shaft 1, and the angle between two adjacent second stirrers 22 is the same, which is a certain angle value between 90 degrees and 180 degrees.

[0044] The first agitator 21 has the following specific structure: it includes a first support base 211 fixedly connected to the main shaft 1, a first support shaft 212 threadedly connected to the first support base 211, and a first blade assembly mounted on the first support shaft 212. The first blade assembly includes three first inner blades 213 arranged sequentially along the axial direction of the first support shaft 212 and one first outer blade 214 located at the outer end of the first support shaft 212. The angles between these four blades and the first support shaft 212 are all different. The sizes of the first inner blades 213 and the first outer blades 214 are also different. The blades further out in the radial direction along the main shaft 1 are larger, and the first outer blade 214 is the largest because it is the outermost. All the first inner blades 213 and the first outer blades 214 are detachably fixed to the first support shaft 212 (e.g., by bolt connection) for easy individual replacement or maintenance.

[0045] The second agitator 22 has the same structure as the first agitator 21, including a second support base 221 fixedly connected to the main shaft 1, a second support shaft 222 threadedly connected to the second support base 221, and a second blade assembly mounted on the second support shaft 222. The second blade assembly includes three second inner blades 223 arranged sequentially along the axial direction of the second support shaft 222 and one second outer blade 224 located at the outer end of the second support shaft 222. The angles between these four blades and the second support shaft 222 are all different. The second inner blades 223 and the second outer blades 224 are also different in size; the blades further out in the radial direction along the main shaft 1 are larger, with the second outer blade 224 being the largest because it is the outermost. The three second inner blades 223 and the one second outer blade 224 are also detachably fixed to the second support shaft 222 (e.g., by bolts) for easy replacement or maintenance.

[0046] During operation, the first agitator 21, with its larger outer diameter, primarily applies a strong centrifugal force to the material, throwing the heavier material against the chamber wall and promoting its upward movement. Meanwhile, the second agitator 22, with its smaller outer diameter, primarily generates a strong axial circulating flow, carrying the lighter material from the upper part to the lower part. The synergistic effect of these two mixing force fields of different intensities and modes of action forces materials of different densities to interpenetrate, thereby achieving uniform mixing.

[0047] There are two scrapers 3, respectively located at the left and right ends of the main shaft 1 and facing each other at 180 degrees. Each scraper 3 includes a scraper support rod 31 that is axially and vertically fixed to the main shaft 1, and a scraper 32 that is detachably fixed to the scraper support rod 31. The scraper 32 has a straight edge 321 near the end wall of the mixing chamber and an arc edge 322 near the peripheral wall of the mixing chamber. The straight edge 321 is 5-8 mm away from the inner wall of the end of the mixing chamber, and the outermost edge of the arc edge 322 is 5-8 mm away from the peripheral wall of the mixing chamber, which is used to effectively scrape off the material adhering to the chamber wall.

[0048] Furthermore, the main shaft 1 is a hollow structure, with an auxiliary airflow channel inside, and micropores communicating with this channel are formed on its side wall. One end of the main shaft 1 is connected to a controllable air source. Thus, the controllable air source, the auxiliary airflow channel, and the micropores together constitute the pneumatic assisted mixing device. This device can introduce a controllable pulsed airflow into the material, generating a local fluidization effect and disturbance, which helps to break up material clumps, especially improving the dispersibility of light fine powders, effectively complementing mechanical stirring.

[0049] In summary, this embodiment, by setting up first and second agitators with specific size ratios and spatial layouts on the main shaft, forms a non-uniform composite mixing force field, effectively suppressing stratification caused by density differences. The modular and detachable design of the agitator blades significantly improves the maintainability of the equipment. Combined with the wall scraping cleaning function and pulsed airflow-assisted mixing, this mixer is particularly suitable for the uniform mixing of materials with large density differences and agglomeration, such as rare earth flame retardants. It has a reasonable structure and high mixing efficiency.

[0050] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A mixer for mixing particulate materials with large density differences, characterized in that, include: Mixing chamber, main shaft (1), stirrer (2) and wall scraper (3); The stirrer (2) and the scraper (3) are both enclosed in the mixing chamber and are fixed on the main shaft (1) and rotate with the main shaft (1); The agitator (2) is a paddle agitator, including a first agitator (21) and a second agitator (22). The length of the second agitator (22) along the radial direction of the main shaft (1) is 0.5-0.8 times the length of the first agitator (21) along the radial direction of the main shaft (1). The number of the first stirrers (21) is not less than 4, two of which are located at the left and right ends of the main shaft (1) and are arranged opposite each other at a 180-degree angle, and the rest are evenly staggered in the middle part of the main shaft (1) along the circumference of the main shaft (1). The number of the second stirrers (22) is twice the number of the first stirrers (21), and they are evenly arranged along the axial direction of the main shaft (1) and are all offset from the axial direction of the first stirrers (21). All the second stirrers (22) are evenly offset along the circumference of the main shaft (1). The scraper (3) is used to remove material adhering to the end wall and peripheral wall of the mixing chamber.

2. The mixer for mixing particulate materials with large density differences according to claim 1, characterized in that, The first agitator (21) includes a first support base (211), a first support shaft (212), a first inner blade (213), and a first outer blade (214). The first support base (211) is fixedly connected to the main shaft (1). The first support shaft (212) and the first support base (211) are threadedly connected. There are three first inner blades (213), which are fixedly connected to the first support shaft (212) in sequence along the axial direction of the first support shaft (212). The first outer blade (214) is fixedly connected to the outer end of the first support shaft (212).

3. The mixer for mixing particulate materials with large density differences according to claim 2, characterized in that, The angles between the three first inner blades (213) and the first support shaft (212), and the angles between the first outer blade (214) and the first support shaft (212) are all different; the sizes of the first inner blades (213) and the first outer blades (214) are also different, with the blades on the outermost side being larger in the radial direction along the main shaft (1).

4. The mixer for mixing particulate materials with large density differences according to claim 1, characterized in that, The second stirrer (22) includes a second support base (221), a second support shaft (222), a second inner blade (223), and a second outer blade (224). The second support base (221) is fixedly connected to the main shaft (1). The second support shaft (222) and the second support base (221) are threadedly connected. There are three second inner blades (223), which are fixedly connected to the second support shaft (222) in sequence along the axial direction of the second support shaft (222). The second outer blade (224) is fixedly connected to the outer end of the second support shaft (222).

5. The mixer for mixing particulate materials with large density differences according to claim 4, characterized in that, The angles between the three second inner blades (223) and the second support shaft (222), and the angles between the second outer blade (224) and the second support shaft (222) are all different.

6. The mixer for mixing particulate materials with large density differences according to claim 5, characterized in that, The second inner blade (223) and the second outer blade (224) are also different in size, with the blades on the outer side being larger in the radial direction of the main shaft (1).

7. The mixer for mixing particulate materials with large density differences according to claim 1, characterized in that, There are two scrapers (3), which are respectively located at the left and right ends of the main shaft (1). The two scrapers (3) located at the left and right ends of the main shaft (1) are arranged 180 degrees opposite each other.

8. The mixer for mixing particulate materials with large density differences according to claim 6, characterized in that, The wall scraper (3) includes a scraper support rod (31) and a scraper (32). The scraper support rod (31) is perpendicular to the axis of the main shaft (1) and is fixedly connected to the main shaft (1). The scraper (32) is detachably fixedly connected to the scraper support rod (31).

9. The mixer for mixing particulate materials with large density differences according to claim 8, characterized in that, The scraper (32) has a planar structure, with a straight edge (321) near the end of the mixing chamber and a rounded edge (322) near the periphery of the mixing chamber. The straight edge (321) is 5-8 mm away from the inner wall of the end of the mixing chamber, and the outermost edge (322) is 5-8 mm away from the periphery of the mixing chamber.

10. The mixer for mixing particulate materials with large density differences according to claim 1, characterized in that, The mixer also includes a pneumatic auxiliary mixing device. The main shaft (1) is a hollow structure. An auxiliary airflow channel is provided inside the main shaft (1). A microhole communicating with the auxiliary airflow channel is opened on the side wall of the main shaft (1). One end of the main shaft (1) is connected to a controllable air source. The auxiliary airflow channel, the microhole and the controllable air source together constitute the pneumatic auxiliary mixing device.

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