A cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas

Abstract

This invention discloses a cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas. It includes a cyclone separator and a double-spiral surface separator. The cyclone separator includes a cyclone cylinder, with its inner cavity's suction port connected to a centrifugal fan. A feed pipe extending tangentially is provided on the outer side of the cylindrical section of the cyclone cylinder. Positive pressure air is introduced from the nozzle side, feeding the material along the feed pipe into the inner cavity of the cyclone cylinder. Several convex ridges are evenly distributed circumferentially on the upper section of the cylindrical wall of the cyclone cylinder's inner cavity. The double-spiral surface separator includes a spiral separation channel, which is divided into upper and lower spaces by a surface screen. The inlet end of the upper space is connected to an inlet channel section, which receives the material falling from the cyclone cylinder's outlet and guides it into the upper space. Advantages of this invention: The composite structure of "cyclone separation + double-spiral surface separation" improves the separation efficiency and accuracy of particles and impurities, resulting in less impurities, less loss, and good miniaturization and adaptability.

Description

Technical Field

[0001] This invention relates to the field of grain cleaning equipment technology, and in particular to a cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas. Background Technology

[0002] Mechanized grain harvesting is a crucial link in ensuring food production security. Currently, combine harvesters in plain areas generally use air-screen cleaning devices, which mainly consist of a blower, a fish-scale screen, a perforated screen, and a vibrating plate. They rely on the combination of airflow and the vibrating screen to separate grains from impurities.

[0003] However, this type of air-screen cleaning device is large in size, vibrates strongly, and consumes a lot of energy, making it difficult to meet the requirements of lightweight, compact, and highly maneuverable small harvesters in hilly and mountainous areas. Most existing small harvesters use a single airflow cleaning method, which has poor adaptability to complex materials containing husks, stems, etc., and suffers from defects such as high cleaning loss rate and excessive impurity content, failing to achieve both low loss and efficient impurity removal.

[0004] Further research revealed that even when using cyclone separation, the upper inner wall of the cyclone tube is prone to forming a local low-speed circulation zone due to the boundary layer effect. The airflow velocity in this area is close to the critical value of the stalk's suspension velocity, which can easily cause the stalk to stick to the wall, spin horizontally, and fail to be discharged in time. This leads to problems such as separation lag, blockage inside the tube, and reduced cleaning continuity. Existing cyclone cleaning devices have not proposed effective solutions to such local flow field defects. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and solve the problems of excessive impurities, large losses, and poor adaptability to miniaturization in traditional small harvester cleaning devices in hilly and mountainous areas. This invention provides a cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas.

[0006] This invention is achieved through the following technical solution: A cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas includes a cyclone separator and a double spiral surface separator arranged vertically. The cyclone separator includes a cyclone cylinder. The air inlet at the top of the inner cavity of the cyclone cylinder is connected to a centrifugal fan through an air inlet pipe. A feed pipe section extending tangentially is provided on the outer side of the cylindrical section of the cyclone cylinder. The inlet end of the feed pipe section is connected to a nozzle, and the outlet end is connected to the inner cavity of the cyclone cylinder. A feeding port is provided on one side of the feed pipe section. Positive pressure air is introduced from the nozzle side to send the material fed from the feeding port into the inner cavity of the cyclone cylinder along the feed pipe section. Several convex ridges are evenly distributed circumferentially on the upper section of the cylindrical section of the inner wall of the cyclone cylinder. The double-helix surface separation device includes a helical separation channel that extends spirally from top to bottom. The helical separation channel is divided into upper and lower spaces by a helical surface screen. The upper space is an open space at the top, while the bottom and side walls of the lower space are closed surfaces. The inlet end of the upper space is connected to an inclined inlet channel section, which is used to receive the material falling from the bottom outlet of the cyclone and guide it into the upper space.

[0007] As a preferred embodiment of the above-mentioned composite grading and cleaning device, the upper space outlet extends a certain distance beyond the lower space outlet, and a grain collection box is provided below the lower space outlet.

[0008] As a preferred embodiment of the above-mentioned composite grading and cleaning device, the bottom plate of the spiral separation channel is coaxially and parallel to the surface screen, and the spiral central axes of the two extend vertically.

[0009] As a preferred embodiment of the above-mentioned composite grading and cleaning device, the spiral pitch of the face screen is set to 300mm, the number of spiral turns is one, and the spiral inclination angle is 24°.

[0010] As a preferred embodiment of the above-mentioned composite grading and cleaning device, the surface screen is a mesh plate with multiple screen holes, the screen hole diameter is 7mm~8mm, and the hole spacing is 8mm~10mm.

[0011] As a preferred embodiment of the above-mentioned composite grading and cleaning device, the length of the ridge extends along the axial direction of the cyclone, and the cross-sectional shape of the ridge is fan-shaped.

[0012] As a preferred embodiment of the above-mentioned composite grading and cleaning device, the nozzle is connected to a positive pressure blower via an air duct.

[0013] As a preferred embodiment of the above-mentioned composite grading and cleaning device, the inlet channel section is fixedly connected to the cyclone through a connecting plate, and the lower end of the inlet channel section is fixedly connected to the upper end of the spiral separation channel.

[0014] As a preferred embodiment of the above-mentioned composite grading and cleaning device, the inner cavity of the cyclone includes a cylindrical section in the middle and constricted conical sections at the upper and lower ends. The bottom of the constricted conical section at the lower end is open to form the discharge port of the cyclone, and the top of the constricted conical section at the upper end is open to serve as the air intake.

[0015] The present invention has the following advantages over the prior art: 1. This invention provides a cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas. It adopts a composite structure of "cyclone separation + double-spiral surface separation," forming a two-stage grading and cleaning system. The first-stage cyclone separator utilizes a dual airflow field generated by the combined action of a positive pressure fan and a centrifugal fan to centrifugally separate light impurities, stalks, and grain kernels within the cyclone chamber. Light impurities and stalks are discharged from the suction port with the airflow. The second-stage double-spiral surface separation device then performs fine separation of stalks and kernels from the remaining material. The two-stage cleaning process is clearly defined and complementary, effectively solving the technical problem of traditional single-stage cleaning methods being unable to simultaneously and efficiently remove both light and heavy impurities. This significantly reduces the impurity content of the cleaned kernels, effectively improving the separation efficiency and grading accuracy of particles and impurities. It features a lightweight, compact structure, accurate screening, and low energy consumption, significantly enhancing the operational reliability and cleanliness of grain harvesters in hilly and mountainous areas.

[0016] 2. The present invention provides a cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas. In its double-spiral separation device, the material is subjected to the dual action of gravity and centrifugal force when moving along the spiral path. Taking advantage of the differences in shape and size between the stalk and the grain, their movement trajectories on the spiral surface are naturally differentiated: the stalk slides along the surface of the screen to the outer edge and is discharged, while the grain passes through the screen holes and falls into the lower space. This structural design does not require additional vibration mechanism or forced conveying device. It can achieve efficient screening by relying solely on the movement of the material itself. The structure is simple, compact, and has low energy consumption.

[0017] 3. The present invention provides a cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas. In its cyclone separation device, a fan-shaped ridge is provided on the inner wall of the upper section of the cylindrical section of the cyclone cylinder. This effectively disrupts the low-speed circulation zone formed by the boundary layer on the inner wall, changes the trajectory of the stalk, and avoids the phenomenon of stalks sticking to the wall, spinning horizontally, and stagnating and unable to be discharged. This ensures that light impurities and stalks are promptly sucked out in the cyclone flow field, significantly improving the smoothness, stability, and continuous operation capability of cyclone separation, and further enhancing the cleaning effect. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure 2 This is a front view of the cyclone separator of the present invention.

[0020] Figure 3 This is a top view of the cyclone separator of the present invention.

[0021] Figure 4 This is a longitudinal cross-sectional view of the cyclone tube of the present invention.

[0022] Figure 5 This is a cross-sectional view of the cyclone cylinder of the present invention, taken from the top of the convex ridge.

[0023] Figure 6 This is a partial cross-sectional view of the double-helix separation device of the present invention.

[0024] The following numbers are labeled in the diagram: 1 Cyclone; 2 Suction pipe; 3 Feed pipe section; 4 Nozzle; 5 Feed port; 6 Ridge; 7 Spiral separation channel; 8 Surface screen; 9 Inlet channel section; 10 Connecting plate; 11 Grain collection box; 12 Screen hole; 13 Upper space; 14 Lower space. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0026] See Figures 1 to 6 This embodiment discloses a cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas. It includes a cyclone separator and a double spiral surface separator arranged vertically. The cyclone separator includes a cyclone cylinder 1. The inner cavity of the cyclone cylinder 1 includes a cylindrical section in the middle and constricted conical sections at the upper and lower ends. The bottom of the constricted conical section at the lower end is open to form the discharge port of the cyclone cylinder 1, and the top of the constricted conical section at the upper end is open to serve as the air intake. The air inlet at the top of the inner cavity of the cyclone 1 is connected to the centrifugal fan through the air inlet pipe 2. The cylindrical section of the cyclone 1 is provided with a feed pipe section 3 extending tangentially on the outer side. The inlet end of the feed pipe section 3 is connected to the nozzle 4, and the outlet end is connected to the inner cavity of the cyclone 1. The nozzle 4 is connected to the positive pressure fan through the air pipe. A feeding port 5 is provided on one side of the feed pipe section 3. The feeding port 5 is funnel-shaped and located at the top of the middle section of the feed pipe section 3. The end of the feeding port 5 is connected to the internal channel of the feed pipe section 3. Positive pressure air is introduced from the nozzle 4 side through the positive pressure fan, and the material fed from the feeding port 5 is sent into the inner cavity of the cyclone 1 along the feed pipe section 3. Several ridges 6 are evenly distributed circumferentially on the upper section of the cylindrical section of the inner cavity wall of the cyclone 1. The length of the ridges 6 extends along the axial direction of the cyclone 1, and the cross-sectional shape of the ridges 6 is fan-shaped.

[0027] The double-helix surface separator includes a spiral separation channel 7, which extends spirally from top to bottom. The spiral separation channel 7 is divided into upper and lower spaces by a spiral-shaped screen 8. The upper space 13 is open at the top, while the bottom and side walls of the lower space 14 are closed. An inclined inlet channel section 9 connects to the inlet end of the upper space 13. The inlet channel section 9 receives material falling from the bottom outlet of the cyclone separator 1 and guides it into the upper space 13. The inlet channel section 9 is fixedly connected to the cyclone separator 1 by welding using several connecting plates 10. The lower end of the inlet channel section 9 is also fixedly connected to the upper end of the spiral separation channel 7 by welding, allowing the entire double-helix surface separator to be suspended below the cyclone separator 1 via the connecting plates 10. The outlet end of the upper space 13 extends a certain distance beyond the outlet end of the lower space 14, and a grain collection box 11 is located below the outlet end of the lower space 14.

[0028] The bottom plate of the spiral separation channel 7 is coaxially and parallel to the surface screen 8, with their spiral axes extending vertically. The spiral pitch of the surface screen 8 is set to 300mm, with one spiral turn and a spiral inclination angle of 24°. This parameter setting can effectively utilize the material's own gravity to provide a suitable downward driving force, preventing material accumulation, and avoiding the problems of increased overall device height and structural redundancy. The surface screen 8 is a mesh plate with multiple screen holes 12. The diameter of the screen holes 12 is 7mm~8mm, and the hole spacing is 8mm~10mm. This ensures that the grains can pass through the screen efficiently, while effectively preventing stalks and other impurities of similar length from falling into the lower space 14 along with the grains.

[0029] In this embodiment, the composite grading and cleaning device, when in operation, feeds a mixture of light impurities, stalks, and grains into the feed pipe section 3 of the cyclone separator from the feed port 5 at a certain initial velocity. A high-speed airflow generated by a positive pressure fan is injected from the nozzle 4, accelerating the mixture and tangentially introducing it into the inner cavity of the cyclone 1. The mixture is suspended within the cyclone 1, and the airflow velocity within the cyclone 1 is stable. Simultaneously, a centrifugal fan draws air from the suction port at the top of the cyclone 1, creating a negative pressure environment within the cyclone 1 under the combined action of the positive pressure fan and the centrifugal fan. Under the combined action of the negative pressure and the tangential airflow, the mixture undergoes a spiral motion along the inner wall of the cyclone 1. Multiple ridges 6 on the upper part of the cylindrical section inside the cyclone 1 disrupt the low-speed circulation zone formed by the boundary layer on the inner wall, altering the trajectory of the stems and preventing long stems from sticking to the wall and becoming stuck, thus ensuring that stems and light impurities can smoothly enter the rising airflow and be promptly sucked out. Because the weight of the grains is greater than that of some stems and light impurities, under the combined action of centrifugal force and gravity, the grains settle near the inner wall of the cyclone 1 and move downwards along the inner wall, eventually falling from the discharge port at the bottom of the cyclone 1 into the inlet channel section 9 of the double-helix surface separator. Meanwhile, the stems and light impurities spiral upwards with the airflow inside the cyclone 1 and are discharged from the suction port, completing the first stage of cleaning.

[0030] A small portion of the stems, along with the grains, falls into the inlet channel section 9 of the double-helix surface separator. After this material is introduced into the upper space 13 from the inlet channel section 9, it moves downwards along the spiral path under the guidance of the spiral screen 8. During this process, the material is subjected to multiple forces: first, the downward component of gravity along the spiral screen 8 provides the main driving force for the material's descent; second, the component of gravity along the inner side of the spiral screen 8 causes the material to tend to move inwards; and third, the centrifugal force generated by the material sliding along the spiral screen 8 causes the material to tend to move outwards. Under the combined action of gravity and centrifugal force, the trajectories of the stems and grains on the spiral screen 8 show a clear differentiation due to differences in shape and size. Under the combined action of gravity and centrifugal force, the stalks slide on the surface of the sieve 8 and continue to slide downwards along the spiral path, eventually being discharged from the end of the sieve 8. As the grains are smaller in size, during their movement on the sieve 8, when they pass through the sieve holes 12, they fall into the lower space 14 under the combined action of gravity and spiral motion, effectively preventing the stalks from falling into the lower space 14 along with the grains, thus achieving precise separation of grains and stalks. The grains that fall into the lower space 14 continue to be transported downwards along the spiral path under the stable guidance of the spiral bottom plate of the lower space 14, and finally collect in the grain collection box 11, completing the grain collection after the second stage of cleaning.

[0031] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cyclone-spiral composite grading and cleaning device suitable for grain harvesting in hilly and mountainous areas, characterized in that: The device includes a cyclone separator and a double-helix separator arranged vertically. The cyclone separator includes a cyclone cylinder (1). The air inlet at the top of the inner cavity of the cyclone cylinder (1) is connected to a centrifugal fan through an air inlet pipe (2). A feed pipe section (3) extending tangentially is provided on the outer side of the cylindrical section of the cyclone cylinder (1). The inlet end of the feed pipe section (3) is connected to a nozzle (4), and the outlet end is connected to the inner cavity of the cyclone cylinder (1). A feeding port (5) is provided on one side of the feed pipe section (3). Positive pressure air is introduced from the nozzle (4) side, and the material fed from the feeding port (5) is sent into the inner cavity of the cyclone cylinder (1) along the feed pipe section (3). Several convex ridges (6) are evenly distributed circumferentially on the upper section of the cylindrical section of the inner cavity wall of the cyclone cylinder (1). The double-helix surface separation device includes a spiral separation channel (7), which extends spirally from top to bottom. The spiral separation channel (7) is divided into upper and lower spaces by a spiral-shaped surface screen (8). The upper space (13) is an open space at the top, and the bottom and side walls of the lower space (14) are closed surfaces. The inlet end of the upper space (13) is connected to an inclined inlet channel section (9). The inlet channel section (9) is used to receive the material falling from the bottom outlet of the cyclone (1) and introduce it into the upper space (13).

2. The cyclone-spiral composite grading and cleaning device for grain harvesting in hilly and mountainous areas as described in claim 1, characterized in that: The outlet of the upper space (13) extends a distance beyond the outlet of the lower space (14), and a grain collection box (11) is provided below the outlet of the lower space (14).

3. The cyclone-spiral composite grading and cleaning device for grain harvesting in hilly and mountainous areas as described in claim 1, characterized in that: The bottom plate of the spiral separation channel (7) and the surface screen (8) are coaxially parallel, and their spiral central axes extend vertically.

4. The cyclone-spiral composite grading and cleaning device for grain harvesting in hilly and mountainous areas as described in claim 3, characterized in that: The spiral pitch of the surface screen (8) is set to 300mm, the number of spiral turns is one turn, and the spiral inclination angle is 24°.

5. The cyclone-spiral composite grading and cleaning device for grain harvesting in hilly and mountainous areas as described in claim 4, characterized in that: The surface screen (8) is a mesh plate with multiple screen holes (12). The diameter of the screen holes (12) of the surface screen (8) is 7mm~8mm and the hole spacing is 8mm~10mm.

6. The cyclone-spiral composite grading and cleaning device for grain harvesting in hilly and mountainous areas as described in claim 1, characterized in that: The length of the ridge (6) extends along the axial direction of the cyclone tube (1), and the cross-sectional shape of the ridge (6) is fan-shaped.

7. The cyclone-spiral composite grading and cleaning device for grain harvesting in hilly and mountainous areas as described in claim 1, characterized in that: The nozzle (4) is connected to the positive pressure fan via a duct.

8. The cyclone-spiral composite grading and cleaning device for grain harvesting in hilly and mountainous areas as described in claim 1, characterized in that: The inlet channel section (9) is fixedly connected to the cyclone tube (1) via the connecting plate (10), and the lower end of the inlet channel section (9) is fixedly connected to the upper end of the spiral separation channel (7).

9. A cyclone-spiral composite grading and cleaning device for grain harvesting in hilly and mountainous areas as described in claim 1, characterized in that: The inner cavity of the cyclone tube (1) includes a cylindrical section in the middle and constricted conical sections at the upper and lower ends. The bottom of the constricted conical section at the lower end is open to form the discharge port of the cyclone tube (1), and the top of the constricted conical section at the upper end is open to serve as the air intake.

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