A biomass particle screening apparatus

Abstract

The utility model discloses a kind of biomass particle screening equipment, including support, further include driving mechanism, sieve cylinder, feed hopper and discharge hopper;The driving mechanism is obliquely fixed on support;The sieve cylinder is coaxially fixed by cross plate and driving mechanism;The feed hopper is fixed on support and the end close to sieve cylinder is inserted into the upper end of sieve cylinder obliquely;The discharge hopper is fixed on support and the end close to sieve cylinder is located in the lower part of sieve cylinder and extends to the middle part of sieve cylinder.The utility model is characterized in that: by setting two-stage screen section and solid transition section of different aperture and according to specific order arrangement, and three independent collecting hopper, three-level separation to fine powder, small particle and qualified particle is realized.Screening limit is clear, effectively avoid the debris mixed into finished product, significantly improve the product quality of final biomass particle.Sieve cylinder is obliquely arranged and the setting of internal throwing plate, material can tumble and automatically migrate along axial direction, the probability of screening is high, processing capacity is large, and it is not easy to block.

Description

Technical Field

[0001] This utility model relates to the technical field, and in particular to a biomass pellet screening device. Background Technology

[0002] Biomass pellets are cylindrical, high-density, clean solid fuels made from agricultural and forestry waste (such as sawdust and straw) through processes such as crushing, drying, and compression. Biomass pellets formed by pellet mills need to be screened to ensure their quality. Existing biomass pellet screening equipment tends to screen out debris and smaller particles simultaneously, which is detrimental to the recycling of biomass pellets. Furthermore, the unclear screening boundaries can result in the final screened product still containing debris, leading to a decline in product quality. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a biomass pellet screening device that ensures the quality of the finished product.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0005] A biomass pellet screening device includes a support frame, a drive mechanism, a screen cylinder, a feed hopper, and a discharge hopper; the drive mechanism is inclinedly fixed to the support frame; the screen cylinder is coaxially fixed to the drive mechanism via a cross plate; the feed hopper is fixed to the support frame and its end near the screen cylinder extends into the inclined upper end of the screen cylinder; the discharge hopper is fixed to the support frame and its end near the screen cylinder is located at the lower part of the screen cylinder and extends towards the middle of the screen cylinder.

[0006] Furthermore, the drive mechanism includes a rotating shaft, a bearing housing, and a motor; both ends of the rotating shaft are rotatably connected to the bearing housing via bearings; the bearing housing is fixedly connected to the support; the motor is fixedly connected to the support near the inclined lower end of the screen cylinder, and its output end is fixedly connected to the rotating shaft.

[0007] Furthermore, the screen cylinder includes a first screen section, a transition section, and a second screen section; the first screen section, the transition section, and the second screen section are coaxially fixedly connected in sequence; the first screen section is located near the motor end.

[0008] Furthermore, the feed hopper is in the shape of a rectangular groove.

[0009] Furthermore, the discharge hopper includes a bottom plate, a surrounding plate, and a confluence plate; the two bottom plates are fixedly connected and have a V-shaped structure with an obtuse angle in cross section; the upper ends of the inclined bottom plates are both vertically fixedly connected to the surrounding plate; the two confluence plates are arranged towards the center line of the two bottom plates and are fixedly connected to the bottom plate and the surrounding plate, and have notches for discharging material.

[0010] Furthermore, a first receiving hopper is fixedly connected to the support directly below the first screen section; a second receiving hopper is fixedly connected to the support directly below the second screen section.

[0011] Furthermore, the first receiving hopper and the second receiving hopper have the same structure, but the first receiving hopper has an additional baffle fixed to the two bottom plates compared to the discharge hopper; the baffle is fixed to the end away from the confluence plate; the screen aperture of the first screen section is larger than that of the second screen section.

[0012] Furthermore, an annular plate is fixedly connected to the inner side of the screen cylinder near one end of the feed hopper to prevent material from overflowing from the top of the screen cylinder.

[0013] Furthermore, the cross plate is provided in two pieces, and the connecting plane is located at two planes that divide the screen cylinder into three equal parts; the discharge hopper extends 20cm towards the middle of the screen cylinder.

[0014] Furthermore, six throwing plates are evenly distributed on the inner side of the screen cylinder; the six throwing plates are staggered with the cross plate.

[0015] The beneficial effects of this utility model are:

[0016] By setting up two-stage sieve sections with different apertures arranged in a specific order, a solid transition section, and three independent collection hoppers, three-stage separation of fine powder, small particles, and qualified particles is achieved. The screening boundaries are clear, effectively preventing debris from mixing into the finished product and significantly improving the final quality of the biomass pellets. The inclined setting of the sieve cylinder and the internal throwing plate allow the material to tumble fully and migrate automatically along the axial direction, resulting in a high pass-through probability, large throughput, and minimal clogging. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0019] Figure 3 This is a schematic diagram of the discharge hopper.

[0020] Figure 4 This is a schematic diagram of the structure of the first receiving hopper and the second receiving hopper;

[0021] Figure 5 This is a schematic diagram showing the positions and structures of the cross plate and the throwing plate.

[0022] In the picture,

[0023] 1-Support, 2-Drive mechanism, 3-Screen cylinder, 4-Feed hopper, 5-Discharge hopper, 6-Cross plate, 7-First receiving hopper, 8-Second receiving hopper, 9-Throwing plate;

[0024] 21-Shaft, 22-Bearing housing, 23-Motor;

[0025] 31-First sieve section, 32-Transition section, 33-Second sieve section, 34-Annular plate;

[0026] 51-Base plate, 52-Enclosure plate, 53-Busher plate, 54-Baffle plate, 55-Notch. Detailed Implementation

[0027] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding of this utility model, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0028] Reference Figure 1-5 As shown, a biomass pellet screening device aims to solve the problems in existing biomass pellet screening technology, such as the easy mixing and under-screening of debris and small-diameter particles, unclear screening boundaries, and resulting in a decline in the quality of the finished product. This device achieves effective separation by setting up multi-stage screens and corresponding independent collection hoppers. The biomass pellet screening device includes a support frame 1, a drive mechanism 2, a screen cylinder 3, a feed hopper 4, and a discharge hopper 5. The drive mechanism 2 is inclined and fixedly connected to the support frame 1. The screen cylinder 3 is coaxially fixedly connected to the drive mechanism 2 via a cross plate 6. The feed hopper 4 is fixedly connected to the support frame 1, with one end near the screen cylinder 3 extending into the inclined upper end of the screen cylinder 3. The discharge hopper 5 is fixedly connected to the support frame 1, with one end near the screen cylinder 3 located at the lower part of the screen cylinder 3 and extending towards the middle of the screen cylinder 3.

[0029] It should be noted that the support frame 1, as the basic support structure of the entire equipment, can be constructed using, for example, Q235 carbon steel square tubing or angle steel, through welding or bolting, ensuring sufficient structural strength and stability. The drive mechanism 2 is the power source for the entire equipment, its function being to drive the screen cylinder 3 to rotate. Its "tilted" setting is a key feature of this embodiment, which allows the axis of the screen cylinder 3 to form an inclination angle (e.g., 5° to 15°) with its horizontal plane while rotating. This allows the material to slowly move from the higher position (feed end) to the lower position (discharge end) along the axial direction of the screen cylinder 3 as it rotates within the screen cylinder 3, relying on the component of gravity. The drive mechanism 2 can be securely connected to the connecting plate on the support frame 1 via bolt holes on the base. The screen cylinder 3 is the core component performing the screening function. The cross plate 6, as a connector and support, transmits the rotational torque of the drive mechanism 2 (specifically, the rotating shaft 21) to the screen cylinder 3 on one hand, and ensures the radial support and coaxiality of the screen cylinder 3 on the other, preventing swaying or eccentricity during rotation. The coaxial connection ensures smooth power transmission and stable screening process. The feed hopper 4 receives biomass pellets from upstream processes (such as pellet mills or elevators) and guides them into the screen cylinder 3. To ensure smooth material entry, the end of the feed hopper 4 closest to the screen cylinder 3 (i.e., the discharge port) extends into the inclined upper end (i.e., the feed inlet) of the screen cylinder 3. This extended design effectively prevents material from overflowing or spilling from the feed inlet of the screen cylinder 3 during feeding. The discharge hopper 5 collects the qualified biomass pellets (i.e., "oversize material") that are discharged from the end of the screen cylinder 3 after screening. Its end closest to the screen cylinder 3 is located at the lower part of the screen cylinder 3 (i.e., the lowest inclined discharge port), and is positioned directly below this discharge port to receive all material that has passed through the entire screen cylinder 3 without being screened.

[0030] Specifically, the drive mechanism 2 includes a rotating shaft 21, a bearing housing 22, and a motor 23. Both ends of the rotating shaft 21 are rotatably connected to the bearing housing 22 via bearings. The bearing housing 22 is fixedly connected to the support 1. The motor 23 is fixedly connected to the support 1 near the lower inclined end of the screen cylinder 3, and its output end is fixedly connected to the rotating shaft 21. The rotating shaft 21 is the main shaft for transmitting torque and can be made of tempered steel, such as 45# steel, to ensure its torsional strength. Both ends of the rotating shaft 21 are rotatably connected to the bearing housing 22 via bearings (e.g., mounted spherical roller bearings, such as UCP205 type). The bearing housing 22 provides stable and reliable rotational support for the rotating shaft 21 and bears part of the radial and axial loads of the screen cylinder 3 and the material. The bearing housing 22 is securely fixed to the support 1 with bolts. The motor 23 is the power source and can be, for example, a Y-series three-phase asynchronous motor (such as Y100L-4 type, power 2.2kW), which is fixedly connected to the support 1 near the lower inclined end of the screen cylinder 3. The output end of the motor 23 is fixed to the end of the rotating shaft 21 through a coupling (such as a flexible pin coupling) or a pulley set, thereby converting electrical energy into mechanical energy and driving the rotating shaft 21 to rotate.

[0031] Specifically, the screen cylinder 3 includes a first screen section 31, a transition section 32, and a second screen section 33; the first screen section 31, the transition section 32, and the second screen section 33 are sequentially and coaxially fixedly connected; the first screen section 31 is located near the motor 23. These three sections are sequentially and coaxially fixedly connected (e.g., by welding) along the axial direction of the screen cylinder 3. Since these three sections are sequentially fixedly connected, the material flow sequence is as follows: the material enters from the feed hopper 4 (upper end), first reaches the second screen section 33, then passes through the transition section 32, and finally reaches the first screen section 31. In order to achieve effective separation of fine materials, small particles, and qualified particles, the screen of the second screen section 33 (i.e., the screen section that the material first contacts) has a first aperture, which is relatively small, for example, set to 2mm~4mm. Its function is to first screen out the debris and powder (i.e., "fine materials") in the biomass pellets. After passing through the screen, the fine material falls into the second receiving hopper 8 located directly below the second screen section 33. After being screened by the second screen section 33, the remaining material (small particles and qualified particles) continues to move downstream under gravity and enters the transition section 32. The cylinder wall of the transition section 32 is a solid plate without screen holes (e.g., rolled and welded steel plate). It has two functions: first, to smoothly transport the material from which the fine material has been removed to the first screen section 31; second, to physically isolate the second receiving hopper 8 below the second screen section 33 and the first receiving hopper 7 below the first screen section 31, preventing the materials collected by the two hoppers from interfering with each other. The first screen section 31 is located at the inclined lower end of the screen cylinder 3, that is, the end near the discharge hopper 5. The screen of the first screen section 31 has a second aperture, which is larger than the first aperture of the second screen section 33, for example, set to 6mm~8mm (depending on the minimum size requirement of qualified particles). Its function is to screen out the biomass particles that are too small and unqualified (i.e., "small particles"). After passing through the screen, these small particles fall into the first receiving hopper 7 located directly below the first screen section 31. Finally, the biomass particles that meet the size requirements (whose diameter is larger than the second aperture) cannot pass through the screen of the first screen section 31. They will move along the inner wall of the screen cylinder 3 to the very end (i.e., the discharge port of the screen cylinder) and be discharged from the discharge port into the discharge hopper 5 directly below.

[0032] Specifically, the feed hopper 4 is a rectangular groove. This shape is easy to manufacture and has a large opening, which facilitates docking with the upstream conveyor belt or screw feeder, ensuring that the material is fed smoothly and evenly into the screen cylinder 3. The feed hopper 4 can be made of, for example, 3mm thick Q235 steel plate by bending and welding.

[0033] Specifically, the discharge hopper 5, used to collect qualified finished product particles, includes a bottom plate 51, a side plate 52, and a confluence plate 53. Two bottom plates 51 are fixedly connected, forming a V-shaped structure with an obtuse angle in their cross-section. This V-shaped structure facilitates the collection of particles to the center of the hopper. The upper inclined ends of both bottom plates 51 are vertically fixed to the side plates 52, which increase the hopper's volume and prevent particles from splashing out during descent. Two confluence plates 53 are located at the ends of the V-shaped bottom plates, inclined towards the centerline of the two bottom plates 51, and fixedly connected (e.g., welded) to the bottom plates 51 and side plates 52. The confluence plates 53 further guide the particles collected in the V-shaped groove to a centralized discharge point, i.e., the discharge notch 55. The notch 55 can be connected to a packaging bag or the conveyor belt of the next process.

[0034] Specifically, a first receiving hopper 7 is fixedly connected to the support 1 directly below the first sieve section 31; a second receiving hopper 8 is fixedly connected to the support 1 directly below the second sieve section 33. The function of the first receiving hopper 7 is to specifically collect the unqualified particles with smaller particle sizes that fall through the sieve of the first sieve section 31 (larger aperture). The function of the second receiving hopper 8 is to specifically collect the fine material and powder that fall through the sieve of the second sieve section 33 (smaller aperture). By setting up independent first and second receiving hoppers 7 and 8, and cooperating with sieve sections with different apertures arranged in a specific order (first the smaller aperture 33, then the larger aperture 31), this equipment successfully separates the two different "undersize materials"—fine powder (collected in receiving hopper 8) and small-diameter particles (collected in receiving hopper 7). This solves the problems of unclear screening boundaries, mixing of debris and small particles leading to difficulties in recycling, and decreased product quality in the prior art. The collected fine material (from receiving hopper 8) can be returned to the granulation process for regranulation, while the small particles (from receiving hopper 7) can also be processed separately as needed, thereby improving the utilization rate of raw materials and the quality of the final product.

[0035] Specifically, the first receiving hopper 7 and the second receiving hopper 8 have the same structure, but with an additional baffle 54 fixed to the two bottom plates 51 compared to the discharge hopper 5; the baffle 54 is fixed to the end away from the confluence plate 53. The baffle 54 is fixed to the end away from the confluence plate 53 (i.e., the rear end of the hopper). Since the screen cylinder 3 is inclined, the material may have a certain axial velocity when falling. The function of the baffle 54 is to prevent the collected fine material or small particles from splashing or sliding out from the rear end (the higher end) of the receiving hopper.

[0036] Specifically, an annular plate 34 is fixedly connected to the inner side of the screen cylinder 3 near the feed hopper 4 to prevent material from overflowing from the top of the screen cylinder 3. The annular plate 34 is essentially a retaining ring with an inner diameter smaller than the inner diameter of the screen cylinder 3. When material enters the rotating screen cylinder 3 from the feed hopper 4, some material may tend to splash backwards towards the feed inlet due to centrifugal force or tumbling. The annular plate 34 effectively blocks this material, ensuring that all material can smoothly enter the second screening section 33, thus improving the screening effectiveness.

[0037] Specifically, two cross plates 6 are provided, with the connecting plane located at two equally divided planes of the screen cylinder 3; the discharge hopper 5 extends 20cm towards the middle of the screen cylinder 3. The cross plate 6 consists of radial spokes (e.g., four, arranged in a cross shape) and a central bushing. The bushing is coaxially fixed to the rotating shaft 21 (e.g., via a key or expansion sleeve), and the outer ends of the spokes are fixed to the inner wall of the screen cylinder 3 (e.g., by welding). Providing two cross plates 6 allows for more stable support of the screen cylinder 3. For example, one is located near the drive end (lower end) of the screen cylinder 3, and the other is located in the middle of the screen cylinder 3 (e.g., at the transition section 32). In this embodiment, the connecting plane can be located at two equally divided planes along the length of the screen cylinder 3, which makes the force on the screen cylinder 3 more even and the rotation smoother. Furthermore, the discharge hopper 5 (the hopper for collecting qualified finished products) extends 20cm towards the middle of the screen cylinder 3 (i.e., in the axial "upstream" direction). This means that the receiving surface (lip of the hopper) of the discharge hopper 5 extends about 20cm into the inner side of the opening at the end of the screen cylinder 3 (i.e., the end of the first screen section 31). The purpose of this design is to ensure that all qualified particles tumbling out from the end of the screen cylinder 3 can fall accurately into the discharge hopper 5, and even those particles that are thrown far away during the tumbling process can be effectively captured to prevent material loss.

[0038] Specifically, six throwing plates 9 are evenly distributed on the inner side of the screen cylinder 3; the six throwing plates 9 are staggered with the cross plate 6. The throwing plate 9 is a strip-shaped plate (also called a lifting plate or guide plate) extending along the axial direction of the screen cylinder 3, and one side is fixed to the inner wall of the screen cylinder 3. The function of the throwing plate 9 is that when the screen cylinder 3 rotates, the throwing plate 9 will lift the biomass particles at the bottom, and after being lifted to a certain height, the particles will fall due to gravity. This process causes the material to continuously tumble and disperse within the cross section of the screen cylinder 3, which can effectively prevent particles from agglomerating or sticking to the wall; on the other hand, it increases the contact opportunity between the particles and the screen and the probability of passing through the screen, significantly improving the screening efficiency; at the same time, this tumbling motion also helps the particles move forward (towards a lower position) along the inclined direction of the screen cylinder. The six throwing plates 9 are staggered in circumferential position with the cross plate 6 (if the spokes of the cross plate also extend along the inner wall). For example, if the spokes of the cross plate 6 are at positions of 0°, 90°, 180°, and 270°, then the throwing plate 9 can be set at positions of 30°, 150°, 210°, and 330° (assuming all six spokes are evenly distributed, then the positions should be 0°, 60°, 120°, 180°, 240°, and 300°, ensuring that it is offset from the spokes of the cross plate). This offset setting prevents material from accumulating at the dead angle between the throwing plate 9 and the cross plate spokes, promoting smooth material flow and cleaning of the screen cylinder.

[0039] The working principle of this utility model:

[0040] The biomass pellets to be screened enter the upper part of the inclined rotating screen cylinder 3 through the feed hopper 4. Blocked by the annular plate 34, the material first enters the second screen section 33. Under the tumbling action of the throwing plate 9, fine particles and powder smaller than the first aperture (e.g., 2-4 mm) pass through the screen and fall into the lower second receiving hopper 8. The remaining material, under gravity and tumbling action, passes through the transition section 32 and enters the first screen section 31 located at the lower inclined end. In the first screen section 31, small-diameter non-compliant particles smaller than the second aperture (e.g., 6-8 mm) pass through the screen and fall into the lower first receiving hopper 7. Qualified biomass pellets larger than the second aperture cannot pass through the screen; they continue to move within the screen cylinder 3 and eventually fall from the end discharge port of the screen cylinder 3 into the discharge hopper 5, and are discharged through the notch 55.

[0041] The embodiments of this utility model have been described in detail above with reference to the accompanying drawings, but this utility model is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this utility model, and these variations still fall within the protection scope of this utility model.

Claims

1. A biomass pellet screening device, comprising a support frame (1), characterized in that: It also includes a drive mechanism (2), a screen cylinder (3), a feed hopper (4), and a discharge hopper (5); the drive mechanism (2) is inclinedly fixed to the support (1); the screen cylinder (3) is coaxially fixed to the drive mechanism (2) through a cross plate (6); the feed hopper (4) is fixed to the support (1) and one end near the screen cylinder (3) extends into the inclined upper end of the screen cylinder (3); the discharge hopper (5) is fixed to the support (1) and one end near the screen cylinder (3) is located at the lower part of the screen cylinder (3) and extends towards the middle of the screen cylinder (3); The sieve cylinder (3) includes a first sieve section (31), a transition section (32), and a second sieve section (33); the first sieve section (31), the transition section (32), and the second sieve section (33) are coaxially fixedly connected in sequence; the first sieve section (31) is located near the motor (23); the mesh size of the first sieve section (31) is larger than that of the second sieve section (33); The screen cylinder (3) has six throwing plates (9) evenly distributed on its inner side; the six throwing plates (9) are staggered with the cross plate (6); The throwing plate (9) is a strip plate that extends axially along the screen cylinder (3).

2. The biomass pellet screening equipment according to claim 1, characterized in that: The drive mechanism (2) includes a rotating shaft (21), a bearing seat (22) and a motor (23); the two ends of the rotating shaft (21) are rotatably connected to the bearing seat (22) through bearings; the bearing seat (22) is fixedly connected to the bracket (1); the motor (23) is fixedly connected to the bracket (1) near the inclined lower end of the screen cylinder (3), and its output end is fixedly connected to the rotating shaft (21).

3. The biomass pellet screening equipment according to claim 1, characterized in that: The feed hopper (4) is in the shape of a rectangular groove.

4. The biomass pellet screening device according to claim 1, characterized in that: The discharge hopper (5) includes a bottom plate (51), a surrounding plate (52), and a confluence plate (53); the two bottom plates (51) are fixedly connected and form a V-shaped structure with an obtuse angle in cross section; the upper ends of the two bottom plates (51) are vertically fixedly connected to the surrounding plate (52); the two confluence plates (53) are arranged towards the center line of the two bottom plates (51) and are fixedly connected to the bottom plate (51) and the surrounding plate (52), and form a notch (55) for discharge.

5. The biomass pellet screening device according to claim 4, characterized in that: A first receiving hopper (7) is fixedly connected to the support (1) directly below the first screen section (31); a second receiving hopper (8) is fixedly connected to the support (1) directly below the second screen section (33).

6. The biomass pellet screening device according to claim 5, characterized in that: The first receiving hopper (7) and the second receiving hopper (8) have the same structure and, compared to the structure of the discharge hopper (5), have an additional baffle (54) fixed to the two bottom plates (51); the baffle (54) is fixed to the end away from the confluence plate (53).

7. The biomass pellet screening device according to any one of claims 1 to 6, characterized in that: An annular plate (34) is fixedly connected to the inner side of the screen cylinder (3) near one end of the feed hopper (4) to prevent material from overflowing from the top of the screen cylinder (3).

8. The biomass pellet screening device according to any one of claims 1 to 6, characterized in that: The cross plate (6) is provided in two pieces, and the connecting plane is located at the two planes that are divided into three equal parts of the screen cylinder (3); the discharge hopper (5) extends 20cm to the middle of the screen cylinder (3).

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