A kind of air supplement device, hammer mill and its air supplement method

Abstract

The application relates to the technical field of pulverizers, in particular to a wind supplementing device, a hammer mill and a wind supplementing method thereof. The wind supplementing device comprises: a first air inlet structure and a second air inlet structure; the first air inlet structure and the second air inlet structure are installed on the body of the hammer mill and symmetrically arranged on the two sides of the feeding pipe of the hammer mill; the air outlets of the first air inlet structure and the second air inlet structure respectively face the two end regions of the rotor shaft of the hammer mill, airflow enters from the two sides of the rotor and flows to the bottom, the screening effect on high-oil, high-humidity, high-fiber materials or light materials is enhanced, the problems that high-oil, high-humidity, high-fiber materials or light materials are prone to be blocked in the pulverizer and the particle size range of the pulverized materials is unstable are solved, and the material screening efficiency is improved and the rotor wear is reduced.

Description

Technical Field

[0001] This invention relates to the field of crusher technology, specifically to an air supply device, a hammer mill, and an air supply method thereof. Background Technology

[0002] Hammer mills are core equipment for powder processing in industries such as feed, grain, food, and biomass. Their core working principle involves high-speed rotating hammers impacting and shearing materials. The pulverized, qualified particles are discharged through screen openings. Smaller screen openings are crucial for achieving fine pulverization and ensuring uniform particle size in the finished product. However, unstable particle size range and clogging issues have long constrained equipment efficiency. The core causes are threefold: (1) Material circulation layer effect: The material moves in a high-speed circular motion along the screen surface under the action of the hammer blades, forming a stable circulation layer. Under the action of centrifugal force, large particles accumulate on the outer periphery of the circulation layer, directly adhering to the screen surface and blocking the screen holes, while preventing small particles on the inner side from contacting the screen surface. This effect is amplified sharply under the condition of small screen holes, which is the core cause of clogging.

[0003] (2) Severe imbalance of sieving force: The sieving of materials must meet the condition that "system suction force > particle centrifugal force + screen hole friction force". The screen of the traditional crusher is installed on both sides, and the upper and lower halves of the screen are opened with screen holes. A vortex is formed on the outer side of the screen in the upper half of the crushing chamber, which will greatly increase the ventilation resistance of the screen. As a result, the effective suction force of the traditional negative pressure suction system will be greatly reduced, and it will be unable to overcome the centrifugal force of the particles. The qualified fine powder cannot be discharged in time and will be repeatedly impacted and agglomerated in the crushing chamber, further aggravating the bridging and blockage of the screen holes.

[0004] (3) Particle adhesion characteristics: The specific surface area of ​​fine particles of high oil, high moisture, high fiber or light materials increases exponentially as the particle size decreases after crushing. The van der Waals forces and capillary adsorption forces between particles are significantly enhanced, making it easy to form adhesion and agglomeration on the inner wall of the sieve hole. This makes the sieve hole smaller and smaller. As time goes on, the particle size of the crushed material will become finer and finer, and the particle size will be unstable, resulting in unqualified product particle size.

[0005] Traditional air supply devices are usually located on the feeder, not at the inlet. There is almost no air supply in the inlet area, which can cause poor feeding or even blockage of some high-oil, high-moisture, high-fiber or lightweight materials.

[0006] High-oil, high-moisture, high-fiber, or lightweight materials are immediately drawn into a circulating layer by the hammer blades upon entering the crushing chamber. Due to the limited pre-crushing area, the material directly adheres to the screen, making discharge difficult. The airflow within the crushing chamber easily forms vortices on the outer upper half of the screen, increasing screen resistance and promoting material accumulation. This causes the screen openings to gradually shrink, resulting in over-crushing of the material within the crushing chamber. The particle size becomes increasingly fine over time, leading to unstable particle size after crushing and even clogging, creating a fire hazard. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide an air supply device, a hammer mill and an air supply method thereof to solve the problems of easy clogging and unstable particle size range of high oil, high moisture, high fiber or light materials in the mill, and to improve the material screening efficiency and reduce rotor wear.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: The first objective of this invention is to provide an air supply device for a hammer mill, comprising: a first air inlet structure and a second air inlet structure; the first air inlet structure and the second air inlet structure are mounted on the body of the hammer mill and symmetrically arranged on both sides of the feed pipe of the hammer mill; the air outlets of the first air inlet structure and the second air inlet structure are respectively directed toward the axial ends of the rotor of the hammer mill.

[0009] By adopting the above scheme, the airflow distribution inside the crushing chamber is optimized by the air intake structure symmetrically arranged on both sides of the feed pipe and with the air outlet facing the two ends of the rotor axis. The airflow enters from both sides of the rotor and flows to the bottom, which enhances the screening effect on high oil, high moisture, high fiber or light materials, while reducing the accumulation of materials at both ends of the rotor axis and reducing the wear at the rotor ends.

[0010] Furthermore, both the first air inlet structure and the second air inlet structure are L-shaped bends and are arranged symmetrically; the L-shaped bend includes a horizontal section and a vertical section, the end of the horizontal section serves as an air inlet, and the lower end of the vertical section serves as an air outlet and connects to the crushing chamber of the hammer mill.

[0011] The above-mentioned design features a relatively high air inlet position, which effectively prevents materials from overflowing from the crushing chamber. The two air inlet structures utilize the negative pressure inside the crusher to achieve natural air replenishment, eliminating the need for an external fan and simplifying the structure.

[0012] Furthermore, it also includes a mounting flange, wherein the first air inlet structure, the second air inlet structure, and the feed pipe are all disposed on the upper part of the mounting flange, and the mounting flange is fixedly connected to the body of the hammer mill. The structure is compact and easy to install, integrating the air supply device and the feed pipe into one unit.

[0013] Furthermore, the air inlets of the first air inlet structure and / or the second air inlet structure are respectively provided with air volume adjustment mechanisms to adjust the opening of the corresponding air inlet. The opening of the make-up air inlet can be flexibly adjusted according to different material characteristics (such as oil content, humidity, fiber content) to adjust the air volume of the make-up air.

[0014] Furthermore, the airflow regulating mechanism includes: a baffle plate, paired mounting plates, and paired adjusting bolts, wherein: A baffle plate is installed at the end of the corresponding air inlet, and bolt holes are opened on both sides of the baffle plate. Pairs of mounting plates are fixed to both sides of the corresponding air inlet, and the mounting plates are provided with vertically arranged oblong holes. Each adjusting bolt passes through the corresponding bolt hole and oblong hole in sequence and is locked with a nut, thereby fixing the baffle plate to the mounting plates on both sides of the air inlet. By adjusting the position of the adjusting bolt in the corresponding oblong hole, the baffle plate moves up and down, changing the opening of the air inlet.

[0015] When adjusting the wind deflector: loosen the nut on the adjusting bolt, move the adjusting bolt to the position in the corresponding oblong hole, so that the wind deflector moves vertically up and down to the target opening; tighten the nut on the adjusting bolt to fix the wind deflector to the mounting plate again, thereby locking the wind deflector in this position and completing the adjustment of the air inlet opening.

[0016] Furthermore, the air inlets of the first air inlet structure and / or the second air inlet structure are equipped with filters to prevent impurities, dust and foreign objects in the outside air from entering the pulverizing chamber.

[0017] Furthermore, the ratio of the cross-sectional area of ​​the vertical section of the L-shaped bend to the cross-sectional area of ​​the feed pipe is 1:5 to 1:10.

[0018] Using the above scheme, since the vertical cross-sectional area of ​​the left and right bends is relatively small compared to the feed pipe, under the negative pressure condition of the crushing chamber, the make-up airflow enters the crushing chamber at a high speed, forming a high-speed airflow path. This high-speed airflow directly washes over the material on the high-speed airflow path, enhancing the screening effect, and on the other hand, it drives the material in the vicinity of the high-speed airflow path to flow, promoting the material to move towards the lower part of the screen and be discharged.

[0019] Furthermore, the heights of both the first and second air inlet structures are lower than the height of the feed pipe, and the height of the feed pipe is preferably between 400 and 600 mm, depending on the process layout.

[0020] The second objective of this invention is to provide a hammer mill, comprising a body, a rotor, a feed pipe, a left screen and a right screen, and the aforementioned air supply device. The air supply device is installed on the mill body; during installation, care must be taken to ensure that the air outlets of the left and right bends are directly opposite the axial ends of the rotor. The left and right screens are symmetrically arranged and installed inside the mill body, concentric with the rotor.

[0021] Using the above scheme, the air supply device utilizes the negative pressure in the crushing chamber to achieve natural air supply. Outside air enters the crushing chamber through the left and right bends. According to Bernoulli's principle, the wind speed is high on both sides and it is discharged from the bottom of the crusher, which is conducive to the material in the area at both ends of the rotor axis passing through the screen plate as soon as possible and reducing the wear at both ends of the rotor axis.

[0022] Furthermore, both the left and right sieve plates include an upper part and a lower part; the upper part of the sieve plate is solid and arc-shaped, with several long teeth on its inner arc surface; the lower part of the sieve plate is arc-shaped and has sieve holes.

[0023] Using the above scheme, the solid arc-shaped structure at the top of the screen plate, combined with the elongated teeth on the inner arc surface, forms a pre-crushing zone. The elongated teeth at the top of the screen plate have a large distribution area, causing the material to undergo multiple impacts and rebounds during the pre-crushing process, thus improving the particle size. The screen plate has no perforations at the top, preventing airflow dispersion and allowing it to pass directly downwards through the perforations at the bottom. This enhances the airflow's effect on high-oil, high-moisture, high-fiber, or lightweight materials, and reduces the vortex phenomenon on the outer side of the upper part of traditional screen plates, improving crushing efficiency. The lower part of the screen plate has large-diameter perforations, reducing material accumulation on the outer side of the screen plate and solving the problem of the crushed material particle size becoming finer over time, thus preventing screen clogging.

[0024] Furthermore, several of the elongated teeth extend along the rotor axis and are evenly distributed in an arc shape on the upper part of the screen plate, ensuring the consistency of the pre-crushing effect in the circumferential direction and improving the overall crushing efficiency.

[0025] Furthermore, the thickness of the sieve plate is 3mm to 5mm, and the depth of the elongated teeth is 0.5 times the thickness of the sieve plate, ensuring the structural strength and wear resistance of the sieve plate; the spacing of the elongated teeth is 3mm to 5mm, providing sufficient space for impact rebound.

[0026] The third objective of this invention is to provide a method for replenishing air in a hammer mill, using the aforementioned hammer mill, wherein the method includes: Under the negative pressure inside the hammer mill, outside air is simultaneously and naturally drawn in through the first air intake structure and the second air intake structure. Outside air enters the crushing chamber from both axial ends of the rotor through the first and second air inlet structures, and flows toward the bottom of the crushing chamber to enhance material screening. By moving the baffles located at the air inlets of the first and second air inlets, the opening size of the air inlets can be changed to adjust the make-up air volume.

[0027] The fourth objective of this invention is to provide a pulverizing method using a hammer mill, wherein the pulverizing method comprises: After the material enters the crushing chamber, it is first struck by the rotor and pre-crushed on the upper part of the screen plate. Multiple impacts and rebounds are formed by the long teeth on the inner arc surface of the upper part of the screen plate. Under the negative pressure inside the hammer mill, outside air is naturally drawn in synchronously through the first air intake structure and the second air intake structure, enters the crushing chamber from the axial end areas of the rotor and flows to the bottom. The airflow passes downward through the screen holes at the bottom of the screen plate to assist the material in passing through the screen and reduce eddies. The crushed material (meeting the particle size requirements) is discharged from the sieve holes at the bottom of the sieve plate.

[0028] The innovation of this invention lies in adding an air supply device to the feed inlet of the crusher and changing the shape and structure of the screen, which makes the airflow through the crusher smoother, enhances the screening effect of the air force on some high-oil, high-moisture, high-fiber or lightweight materials, reduces the phenomenon of eddies, and improves crushing efficiency; at the same time, it can also solve the problem of unstable crushing particle size and screen clogging caused by the accumulation of materials on the screen.

[0029] When high-oil, high-moisture, high-fiber, or lightweight materials pass through the feed pipe of the supplementary air device, the new structure optimizes the internal airflow distribution, making the airflow through the pulverizer smoother. Adjusting the opening of the baffle plate enhances the sieving effect of the airflow on the material, reducing material blockage at the feed point. Since the air outlets of the left and right curved pipes are directly opposite the two edges of the rotor, according to Bernoulli's principle, the air volume on both sides is higher, accelerating the sieving speed of the airflow on both sides and reducing rotor wear.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Improve feeding efficiency: The air supply device optimizes the distribution of internal airflow, increases the feeding speed of high-oil, high-moisture, high-fiber or lightweight materials, and reduces the phenomenon of material blockage at the feed inlet of the crusher.

[0031] 2. Improved crushing efficiency: The large-area elongated tooth structure on the upper part of the screen plate enhances the pre-crushing effect on high-oil, high-moisture, high-fiber materials or lightweight materials.

[0032] 3. Improve the stability of crushed particle size: By reducing the vortex phenomenon on the upper outer side of the screen, the material will quickly exit the screen from the larger screen holes at the bottom of the screen, which solves the problem that the particle size of the crushed material becomes finer over time and also avoids the problem of screen clogging. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the hammer mill of the present invention; Figure 2 for Figure 1 Side view; Figure 3 This is a schematic diagram of the air supply device in this invention; Figure 4 for Figure 3 A three-dimensional image; Figure 5 This is a schematic diagram of the sieve plate in the present invention; In the diagram: Air supply device 1, left bend pipe 11, right bend pipe 12, wind deflector 13, bolt hole 131, mounting plate 14, oblong hole 141; 2. Sieve plate 2, upper part of sieve plate 21, lower part of sieve plate 22, long toothed strip 23; 3. Hammer mill body; 4. Rotor; 5. Mounting flange; 6. Feed pipe. Detailed Implementation Example

[0034] This embodiment describes a supplementary air device 1 applied to a hammer mill, such as... Figure 3 , Figure 4 As shown, it includes: an L-shaped left bend 11 and an L-shaped right bend 12. The L-shaped left bend 11 and L-shaped right bend 12 are installed on the body 3 of the hammer mill and are symmetrically arranged on both sides of the feed pipe 6 of the mill. The L-shaped bend includes a horizontal section and a vertical section. The end of the horizontal section serves as an air inlet, and the lower end of the vertical section serves as an air outlet and connects to the crushing chamber. The air outlets of the two bends face the axial directions of the rotor 4 of the hammer mill at both ends.

[0035] In one embodiment, such as Figures 1 to 4 As shown, the L-shaped left bend 11, the L-shaped right bend 12, and the feed pipe 6 are all located on the upper part of the mounting flange 5, and the mounting flange 5 is fixedly connected to the hammer mill body 3.

[0036] In one embodiment, the air inlets of the left bend pipe 11 and the right bend pipe 12 are respectively provided with air volume adjustment mechanisms to adjust the opening degree of the corresponding air inlets.

[0037] In one embodiment, such as Figure 4As shown, the airflow adjustment mechanism includes: a baffle plate 13, paired mounting plates 14, and paired adjusting bolts. The baffle plate 13 is positioned at the end of the corresponding air inlet, and bolt holes 131 are respectively provided on both sides of the baffle plate. The paired mounting plates 14 are respectively fixed to both sides of the corresponding air inlet, and the mounting plates are provided with vertically arranged oblong holes 141. Each adjusting bolt passes through the corresponding bolt hole and oblong hole in sequence and is locked with a nut, thereby fixing the baffle plate to the mounting plates on both sides of the air inlet. When adjusting the baffle plate: loosen the nut on the adjusting bolt, move the adjusting bolt to the position in the corresponding oblong hole, so that the baffle plate moves vertically up and down to the target opening; tighten the nut on the adjusting bolt to fix the baffle plate to the mounting plate again, thereby locking the baffle plate in this position and completing the adjustment of the air inlet opening.

[0038] In one embodiment, filters are provided at the air inlets of the left bend 11 and the right bend 12.

[0039] In one embodiment, the ratio of the cross-sectional area of ​​the vertical section of the left and right bends to the cross-sectional area of ​​the feed pipe is 1:5 to 1:10.

[0040] In one embodiment, the heights of both the left and right bends are lower than the height of the feed pipe, and the height of the feed pipe is preferably between 400 and 600 mm. Example

[0041] This embodiment is a hammer mill, including a hammer mill body 3, a rotor 4, a feed pipe 6, two screens 2 (left and right), and the aforementioned air supply device 1. Figure 1 , Figure 2 As shown, the air supply device 1 is installed on the body 3 of the crusher. When installing, it should be noted that the air outlets of the left and right bends should be directly opposite the axial ends of the rotor.

[0042] The air supply device utilizes the negative pressure inside the crushing chamber to achieve natural air supply. Outside air enters the crushing chamber through the left and right bends. According to Bernoulli's principle, the air velocity is high on both sides and it is discharged from the bottom of the crusher. This facilitates the material in the areas at both ends of the rotor axis to pass through the screen plate as quickly as possible, reducing wear at both ends of the rotor axis.

[0043] In one embodiment, such as Figure 5 As shown, both the left and right sieve plates include an upper part 21 and a lower part 22; the upper part 21 is a solid arc shape, and its inner arc surface is provided with several long teeth 23; the lower part 22 is arc-shaped and has sieve holes.

[0044] In one embodiment, several elongated teeth extend along the rotor axis and are evenly distributed in an arc shape on the upper part of the screen plate.

[0045] In one embodiment, the thickness of the sieve plate is 3mm to 5mm, the depth of the elongated teeth is 0.5 times the thickness of the sieve plate, and the spacing between the elongated teeth is 3mm to 5mm. Example

[0046] This embodiment describes a method for supplementing air to a hammer mill: Under the negative pressure inside the hammer mill, outside air is simultaneously and naturally drawn in through the left and right bends; outside air enters the crushing chamber from both ends of the rotor's axial direction through the left and right bends and flows towards the bottom of the crushing chamber to enhance material screening; by moving the baffles set at the air inlets of the left and right bends, the opening size of the air inlets is changed to adjust the supplementary air volume. Example

[0047] This embodiment describes a crushing method using a hammer mill: After the material enters the crushing chamber, it is first struck by the rotor to the upper part 21 of the screen for pre-crushing. Multiple impacts and rebounds are formed by the long teeth 23 on the inner arc surface of the upper part 21 of the screen. Under the negative pressure inside the hammer mill, outside air is simultaneously and naturally drawn in through the left and right curved pipes, enters the crushing chamber from the axial ends of the rotor 4 and flows to the bottom. The airflow passes downward through the screen holes of the lower part 22 of the screen plate to assist the material in passing through the screen and reduce eddies. The crushed material (meeting the particle size requirements) is discharged from the screen holes at the lower part of the screen plate.

Claims

1. An air supply device, applied to a hammer mill, characterized in that, include: The first air inlet structure and the second air inlet structure are installed on the body of the hammer mill and are symmetrically arranged on both sides of the feed pipe of the hammer mill. The air outlets of the first air inlet structure and the second air inlet structure are respectively directed toward the two ends of the rotor axis of the hammer mill.

2. The air supply device according to claim 1, characterized in that, Both the first and second air inlet structures are L-shaped bends and are arranged symmetrically. The L-shaped bend includes a horizontal section and a vertical section. The end of the horizontal section serves as an air inlet, and the lower end of the vertical section serves as an air outlet and connects to the crushing chamber of the hammer mill.

3. The air supply device according to claim 1, characterized in that, It also includes a mounting flange, wherein the first air inlet structure, the second air inlet structure and the feed pipe are all disposed on the upper part of the mounting flange, and the mounting flange is fixedly connected to the body of the hammer mill.

4. The air supply device according to claim 2, characterized in that, The first air inlet structure and / or the second air inlet structure are respectively provided with an air volume adjustment mechanism to adjust the opening degree of the corresponding air inlet.

5. The air supply device according to claim 4, characterized in that, The air volume regulating mechanism includes: A wind deflector is provided at the end of the corresponding air inlet, and bolt holes are provided on both sides of the wind deflector; The mounting plates are arranged in pairs and fixed to both sides of the corresponding air inlet. The mounting plates are provided with vertically arranged waist-shaped holes. The adjusting bolts are arranged in pairs, with each adjusting bolt passing through the corresponding bolt hole and the slotted hole in sequence, and then locked with a nut; By adjusting the position of the adjusting bolt in the corresponding oblong hole, the baffle plate can be moved up and down, thereby changing the opening of the air inlet.

6. The air supply device according to claim 1, characterized in that, A filter screen is provided at the air inlet of the first air inlet structure and / or the second air inlet structure.

7. The air supply device according to claim 2, characterized in that, The ratio of the cross-sectional area of ​​the vertical section of the L-shaped bend to the cross-sectional area of ​​the feed pipe is 1:5 to 1:

10.

8. The air supply device according to claim 2, characterized in that, The heights of both the first and second air inlet structures are lower than the height of the feed pipe.

9. A hammer mill, comprising a body, a rotor, a feed pipe, a left screen, and a right screen, characterized in that, It also includes the make-up air device as described in any one of claims 1 to 8.

10. A hammer mill according to claim 9, characterized in that, Both the left and right sieve plates include an upper part and a lower part; the upper part of the sieve plate is solid and arc-shaped, with several long teeth on its inner arc surface; the lower part of the sieve plate is arc-shaped and has sieve holes.

11. A hammer mill according to claim 10, characterized in that, Several of the elongated teeth extend along the rotor axis and are evenly distributed in an arc shape on the upper part of the screen plate.

12. A hammer mill according to claim 11, characterized in that, The thickness of the sieve plate is 3mm to 5mm, and the depth of the elongated teeth is 0.5 times the thickness of the sieve plate; the spacing of the elongated teeth is 3mm to 5mm.

13. A method for replenishing air in a hammer mill, characterized in that, The air supply method is implemented using a hammer mill as described in any one of claims 9 to 12, wherein the air supply method includes: Under the negative pressure inside the hammer mill, outside air is simultaneously and naturally drawn in through the first air intake structure and the second air intake structure. Outside air enters the crushing chamber from both axial ends of the rotor through the first and second air inlet structures, and flows towards the bottom of the crushing chamber to enhance material screening.

14. A crushing method using a hammer mill, characterized in that, The hammer mill as described in any one of claims 9 to 12, wherein the pulverizing method comprises: After the material enters the crushing chamber, it is first struck by the rotor and pre-crushed on the upper part of the screen plate. Multiple impacts and rebounds are formed by the long teeth on the inner arc surface of the upper part of the screen plate. Under the negative pressure inside the hammer mill, outside air is naturally drawn in synchronously through the first air intake structure and the second air intake structure, enters the crushing chamber from the axial end areas of the rotor and flows to the bottom. The airflow passes downward through the screen holes at the bottom of the screen plate to assist the material in passing through the screen and reduce eddies. The crushed material is discharged from the sieve holes at the bottom of the sieve plate.

Images