An under-forest small-particle seed fertilization and mixed sowing machine and an operation method thereof

Abstract

A small-particle seed fertilizer mixing and sowing machine for forestry belongs to the field of forestry machinery technology. It includes a frame and a transmission device mounted on it, a rotary tillage and fertilization unit, a sowing unit, and a pneumatic collection and dispensing device. Multiple sowing units are arranged side-by-side at row spacing. The pneumatic collection and dispensing device includes seed boxes, a fan, an eccentric mixing chamber, and a distributor. Multiple seed boxes are set according to seed type. The seed dispensing pipes of various boxes are connected to form a main seed dispensing pipe, which is connected to the air supply pipe of the fan. The main pipe connects to the air supply pipe of the fan, which in turn connects to the eccentric mixing chamber. The eccentric mixing chamber is connected to the distributor via a corrugated pipe, and the distributor head connects to the sowing pipes of each sowing unit for sowing. This invention is suitable for mixed sowing of small-particle green manure crops such as hairy vetch and oats, and has advantages such as good sowing uniformity, stable seed supply, high operating efficiency, and strong adaptability to different soil surfaces.

Description

Technical Field

[0001] This invention belongs to the field of forestry machinery technology, and in particular relates to a small-particle seed fertilization and mixing machine for forest understory and its operation method. Background Technology

[0002] With the deepening of the concept of sustainable agricultural development, the planting and application of green manure crops are receiving increasing attention. The mixed sowing of small-particle green manure crops such as hairy vetch and oats can effectively improve soil structure and increase soil organic matter content, making it an important measure to improve arable land quality and achieve increased efficiency with reduced fertilizer application. However, traditional sowing machinery faces the following technical challenges when applied to the mixed sowing of small-particle green manure crops: poor mixing uniformity: different crop seeds have significantly different physical characteristics (such as particle size, density, and flowability), making it difficult for traditional mechanical seed metering devices to achieve uniform mixing, resulting in unstable sowing ratios; insufficient seed supply stability: small seeds are prone to bridging and clogging within the seed metering device, affecting seed supply continuity and sowing accuracy; complex operation procedures: rotary tillage and sowing operations usually need to be carried out in separate steps, leading to low operation efficiency and increased costs.

[0003] To address the aforementioned problems, while existing technologies such as CN120787565A offer some improved seeding machinery and techniques that can achieve arbitrary proportions of mixed grass seeds, they still fall short in achieving uniformity of mixing and operational efficiency. Furthermore, they are unsuitable for use in forest land or other compacted soils and cannot improve the quality of arable land. Therefore, there is an urgent need for a new type of seeding machinery that integrates rotary tillage, fertilization, and seeding functions, and effectively solves the technical challenges of mixed sowing of small-particle green manure crops. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a small-particle seed fertilizer mixing machine for forest understory and its operating method. The integrated design of the rotary tillage fertilizer unit simplifies the machine structure, and the pneumatic collection and discharge device with an eccentric mixing chamber solves the problems of inconsistent discharge rates and uneven seed mixing during small-particle seed mixing.

[0005] The objective of this invention is achieved through the following technical solution: This invention discloses a small-particle seed fertilizer mixing and sowing machine for forest understory, comprising a frame and a transmission device, a rotary tillage and fertilization unit, a seeding unit, and a pneumatic collection and dispensing device mounted on it. The input end of the transmission device is connected to a tractor power source, and the output end is connected to the rotary tillage shaft of the rotary tillage and fertilization unit and the blower of the pneumatic collection and dispensing device, respectively. Multiple seeding units are arranged side-by-side according to row spacing. The pneumatic collection and dispensing device includes a seed box, a blower, an eccentric mixing chamber, and a distributor. Multiple seed boxes are arranged according to seed type, and the seed dispensing pipes of various boxes are connected to form a main seed dispensing pipe, which is connected to the air supply pipe of the blower for air delivery. The tubes are connected to the eccentric mixing chamber via Venturi tubes and seed delivery tubes. The eccentric mixing chamber is connected to the distributor via a corrugated tube. The distributor has seed inlets corresponding to the number of seeding units, which are connected to the seeding tubes of each seeding unit. Seeds fall freely from the seed metering manifold into the Venturi tube, where they mix with the high-speed airflow generated by the fan to form a two-phase flow of air and seeds. The mixture is then transported to the eccentric mixing chamber via the seed delivery tube connected to the Venturi tube. After the seeds and airflow are fully mixed and homogeneous, they are pressurized and mixed by the corrugated tube before entering the distributor. After being evenly distributed, the mixture is sown through the seeding tubes of the seeding units.

[0006] Furthermore, the eccentric mixing chamber is an inclined hollow ellipsoidal structure, consisting of an ellipsoid and transition sections connecting the two ends of the ellipsoid. The two transition sections are tangentially connected to the outer side of the ellipsoid and are connected to the seed delivery pipe and the corrugated pipe through the transition sections, so that the seed delivery pipe and the corrugated pipe are arranged in parallel and staggered manner. After the gas-seed two-phase flow enters the eccentric mixing chamber, it forms a rotational tendency under the action of the tangential velocity component, which enhances the lateral migration of particles and local vortex mixing. The inclined asymmetric hollow ellipsoidal structure induces a redistribution of the airflow velocity field and pressure field, so that the seeds are more fully remixed before entering the corrugated pipe.

[0007] Furthermore, the hollow ellipsoidal structure parameters of the eccentric mixing chamber are: pitch angle θ is 30~80°, semi-major axis a is 50~100mm and semi-minor axis b is 25~45mm, wherein the pitch angle θ is the angle between the major axis and the y-axis of the mixing chamber.

[0008] Furthermore, the Venturi tube is composed of an airflow inlet pipe, a seed inlet pipe, a diffuser pipe, and a mixing pipe connected in sequence. The seed inlet pipe is positioned between the airflow inlet pipe and the diffuser pipe, and is perpendicular to both. The airflow inlet pipe has a stepped inner diameter, and its outlet end is a frustoconical tube I, with its inner diameter gradually decreasing from the airflow inlet end to the outlet end. The frustoconical tube I at the outlet end intersects with the diffuser pipe and the seed inlet pipe. The diffuser is a frustoconical tube II with its inner diameter gradually increasing from the inlet end to the outlet end. The mixing pipe has the same inner diameter as the seed delivery pipe. The diameter dt of the frustoconical tube I is 0.40 to 0.50 times the inner diameter D of the seed delivery pipe. The injection angle α of the frustum-shaped tube I is 40–60°, and the diffusion angle β of the diffuser tube is 10–15°. The airflow inlet pipe is connected to the fan, the seed inlet pipe is connected to the seed box, and the mixing pipe is connected to the seed conveying pipe. The seeds discharged from the seed discharge main pipe and the high-speed airflow generated by the fan form a two-phase flow of gas and seed in the diffuser tube. After being compressed at the position of the frustum-shaped tube I, the speed increases and the pressure decreases. The airflow speed reaches its maximum at the contraction point at the end of the frustum-shaped tube I, and a negative pressure is formed at the seed inlet of the diffuser tube, which transports the two-phase flow of gas and seed to the diffuser tube and the mixing tube to complete the mixing.

[0009] Furthermore, the seed delivery pipe is an L-shaped bent pipe, and the lateral length L between the lateral port of the L-shaped bent pipe and the longitudinal centerline of the pipe is... t The longitudinal length H between the longitudinal end of the L-shaped bend and the transverse centerline is 80–100 mm. t The bend radius R of the seed delivery tube is 180-200mm. t The diameter of the seed delivery tube is 35-45 mm, and the inner diameter D of the seed delivery tube is 45-53 mm. The seeds that have been initially mixed in the Venturi tube are transported to the eccentric mixing chamber to complete the second mixing.

[0010] Furthermore, the minimum inner diameter of the corrugated pipe is the same as the inner diameter of the seed delivery pipe, and the effective length Hp of the corrugated section is 120~180mm. After the high-speed gas-seed two-phase flow is mixed twice in the eccentric mixing chamber, it is further buffered, rectified and stabilized in the corrugated pipe with periodic zigzag undulations on the inner wall, so that the seeds form a relatively uniform and stable suspended flow state before entering the distributor.

[0011] Furthermore, the distributor includes an inlet section, a distribution cavity, and multiple seed-guiding channels. A V-shaped distribution cavity is formed between the inlet section and the multiple seed-guiding channels. Each seed-guiding channel has a seed-guiding port at its end. The seed-guiding channels are evenly spaced along the outer circumference of the inlet section. Each seed-guiding channel consists of horizontal and vertical sections. The horizontal sections are radially distributed along the circumference of the distribution cavity, and the vertical sections are circumferentially distributed along the inlet section. The axes of the inlet section and the seed-guiding ports are parallel, and the gas and seed phases flow in opposite directions. The V-shaped angle of the top end cap of the V-shaped distribution cavity... The angle is 105-120°, the inlet section is connected to the corrugated pipe, and the seed guide port is connected to the seed tube of the seeding unit.

[0012] Furthermore, the rotary tillage and fertilization unit includes a rotary tillage roller, a fertilizer application pipe and a fertilizer box set above the rotary tillage roller. There are multiple fertilizer application pipes, which are connected to the two side plates of the frame above the front of the rotary tillage roller through the mounting plate. One end of the fertilizer application pipe is connected to the fertilizer discharge port of the fertilizer box through a steel wire hose, and the other end passes through the mounting plate corresponding to the rotary tillage roller. While rotary tilling and loosening the soil, fertilizer is applied into the soil and mixed with the soil.

[0013] Furthermore, an integral compaction roller is provided between the rotary tiller and the seeder / furrow opener below the frame. The integral compaction roller is installed between the two side plates of the frame to compact the soil after rotary tillage.

[0014] The operating method of the aforementioned forest understory small-particle seed fertilization and mixing machine includes: Rotary tillage and fertilizer mixing steps: As the machine moves forward, the rotary tillage blades of the rotary tillage and fertilizer application unit break up the compacted soil. At the same time, fertilizer is spread in the area in front of the rotary tillage blades through the fertilizer application pipe. During the process of breaking up the soil, the rotary tillage blades force the fertilizer to mix with the soil, forming a seedbed with evenly distributed nutrients. Pneumatic mixing process: The seed metering motor drives the spiral seed metering wheel to force the seeds out of multiple seed boxes. The high-speed airflow generated by the fan draws the seeds in through the Venturi tube and transports them to the eccentric mixing chamber. The gas-seed two-phase flow is forced to mix evenly under the action of eddies and turbulence in the eccentric mixing chamber, forming a gas-seed two-phase flow with uniform seed distribution. Contour-based precision seeding steps: The uniformly mixed gas-seed two-phase flow is stabilized through a corrugated pipe and then enters the distributor, where it is evenly distributed to the seeding tubes of each seeding unit, precisely guiding the seeds into the seed furrow, and completing the soil covering and compaction operations.

[0015] The beneficial effects of this invention are as follows: 1. This invention features a rotary tiller roller at the front end of the fertilizer-mixing seeder. This roller loosens compacted soil before sowing, providing favorable conditions for subsequent planting. The fertilizer box is connected to a fertilizer pipe located above the rotary tiller roller via a flexible steel wire hose, enabling pre-fertilization during the rotary tillage process. This ensures even distribution of fertilizer in the soil, preventing subsequent seed burning. It avoids the need for separate fertilization furrows in previous fertilizer-mixing seeders, which required separate fertilization furrows to prevent seed burning. The invention utilizes a pneumatic seed mixing device to ensure uniform mixing of small seeds, distributing them to the seeding units. During mixed sowing, the discharge rate remains consistent across rows, resulting in a simple and reliable structure.

[0016] 2. The pneumatic seed metering device used in this invention employs a spiral seed metering wheel, combined with a fan airflow. The seeds, after mixing in an eccentric mixing chamber, are evenly distributed to individual seeding plants via a distributor. Compared to the grooved wheel structure of the more common mechanical external grooved wheel seed metering device, the spiral seed metering wheel, due to its inherent structural limitations, results in discontinuous seeding for small seeds, leading to a large coefficient of variation between plants and uneven seeding density between rows. In contrast, this invention uses a spiral seed metering wheel combined with air-blowing seeding to achieve uniform seeding density. The eccentric mixing chamber generates a two-phase flow, ensuring consistent seed distribution in space before blowing out seeds in mixed sowing conditions of two or more seeds in any proportion. This guarantees consistent seed quantity and sowing type between rows after blowing out seeds. While existing pneumatic seed metering devices can achieve better continuity in seeding between rows than mechanical seed metering devices, they cannot achieve uniform seed mixing in mixed sowing conditions.

[0017] 3. This invention transmits power through a transmission device and, through the coordinated operation of a pneumatic collection and discharge device, a rotary tillage and fertilization unit, and a seeding unit, forms an operational process of rotary tillage-fertilization-overall compaction-ditching-seeding-covering and individual compaction. It enables fertilization and mixed seeding of multiple types of seeds in compacted soils or forest soils, which is impossible with existing seeders. Furthermore, the fertilization and seeding processes are entirely controlled by electric motors, allowing for precise control of time, amount, and seed quantity, and eliminating the need for ground wheels, resulting in a simple and reliable overall machine structure. Attached Figure Description

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

[0019] Figure 2 for Figure 1 Schematic diagram of the transmission device.

[0020] Figure 3 for Figure 1 Schematic diagram of a pneumatic gas collection and discharge device.

[0021] Figure 4 for Figure 3 Schematic diagram of Chinese tuyeres structure parameters.

[0022] Figure 5 for Figure 3 Schematic diagram of the structural parameters of the seed delivery tube.

[0023] Figure 6 for Figure 3 Schematic diagram of the structural parameters of the eccentric mixing chamber.

[0024] Figure 7 for Figure 3 Schematic diagram of the structural parameters of the corrugated pipe.

[0025] Figure 8 for Figure 3Schematic diagram of the structural parameters of the distributor.

[0026] Figure 9 for Figure 1 Schematic diagram of the structure of the seeding unit.

[0027] In the diagram: 1. Frame; 11. Three-point suspension device; 12. Side plate; 2. Transmission device; 21. Gearbox; 211. Input end; 212. Output shaft; 22. Belt drive assembly; 3. Pneumatic collection and discharging device; 31. Fan; 32. Seeding motor; 33. Seed box; 34. Venturi tube; 341. Airflow inlet pipe; 342. Seed inlet pipe; 343. Diffusion pipe; 344. Mixing pipe; 35. Seed conveying pipe; 36. Eccentric mixing chamber; 361. Ellipsoid; 362. Transition section; 37. Corrugated pipe; 38. Distributor; 381. Inlet section; 382. Seed guide port; 383. Distribution chamber; 384. End cap; 385. Seed guide channel; 4. Rotary tillage and fertilization unit; 41. Rotary tillage blade shaft; 42. Fertilizer box; 43. Rotary tillage blade; 44. Integrated compactor; 45. Fertilizer pipe; 5. Seeding unit, 51. Contouring wheel, 52. Four-bar contouring mechanism, 521. Contouring spring, 522. Adjusting handle, 53. Furrow opener, 54. Covering plate, 55. Pressing wheel. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] Example 1: As Figures 1-9 As shown, this invention discloses a small-particle seed fertilizer mixing and sowing machine for forest understory, comprising a frame 1 and a transmission device 2, a rotary tillage and fertilization unit 4, a seeding unit 5, and a pneumatic collection and dispersing device 3 mounted thereon. The input end of the transmission device 2 is connected to a tractor power source, and the output end is connected to the rotary tillage shaft 41 of the rotary tillage and fertilization unit 4 and the blower 31 of the pneumatic collection and dispersing device 3, respectively. Multiple seeding units 5 are arranged side-by-side at row spacing. The pneumatic collection and dispersing device 3 includes a seed box 33, a blower 31, an eccentric mixing chamber 36, and a distributor 38. Multiple seed boxes 33 are arranged in parallel according to seed type. The seed dispensing pipes of each seed box 33 are connected to form a seed dispensing main pipe, which is connected to the air supply pipe of the blower 31. The air supply pipe is connected to the eccentric mixing chamber 36 through the Venturi tube 34 and the seed delivery pipe 35. The eccentric mixing chamber 36 is connected to the distributor 38 through the corrugated pipe 37. The distributor 38 has seed guide ports corresponding to the number of seeding units 5, which are connected to the seeding pipes of each seeding unit 5. In this example, the working wind speed v of the blower 31 of the pneumatic collection and dispensing device 3 is... aAt a speed of 28–30 m / s, the seeds in the seed box 33 fall freely through the seed discharge manifold into the venturi tube 34 and mix with the high-speed airflow generated by the fan 31 to form a two-phase flow of gas and seeds. The mixture then enters the eccentric mixing chamber 36 through the seed delivery pipe 35 connected to the venturi tube 34 for enhanced and uniform mixing. After being pressurized and mixed by the corrugated pipe 37, the mixture enters the distributor 38, where the seeds are evenly distributed. Finally, the seeds are sown through the sowing tube of the sowing unit 5.

[0030] like Figure 6 As shown, the eccentric mixing chamber 36 is an inclined hollow ellipsoidal structure, consisting of an ellipsoid 361 and transition sections 362 connecting the two ends of the ellipsoid. In this example, the length of the transition sections is 40 mm. The two transition sections are tangentially connected to the outer side of the ellipsoid and are connected to the seed delivery pipe 35 and the corrugated pipe 37 through the transition sections, so that the seed delivery pipe 35 and the corrugated pipe 37 are arranged in parallel and staggered manner. After the gas-seed two-phase flow enters the eccentric mixing chamber 36, it forms a certain rotational tendency under the action of the tangential velocity component, which enhances the lateral migration of particles and the local eddy mixing effect. Compared with the traditional straight-through expansion cavity, the eccentric mixing chamber 36 not only provides a larger particle redistribution space, but also induces the redistribution of the airflow velocity field and pressure field through the inclined asymmetric hollow ellipsoidal structure, so that the seeds are more fully remixed before entering the corrugated pipe 37.

[0031] like Figure 6 As shown, the hollow ellipsoidal structure parameters of the eccentric mixing chamber 36 are: pitch angle θ is 45°, semi-major axis a is 70mm and semi-minor axis b is 35mm, major axis is 140mm and minor axis is 70mm. Among them, pitch angle θ is the angle between the major axis of the hollow ellipsoidal structure and the horizontal y-axis. The above parameters mainly affect the mainstream direction and the position of the local recirculation zone. Semi-major axis a mainly affects the residence time of particles in the chamber and the length of the flow field development. Semi-minor axis b mainly affects the lateral diffusion space and the probability of local collision.

[0032] like Figure 5 As shown, the seed delivery tube 35 is a crucial component connecting the Venturi tube 34 and the eccentric mixing chamber 36. Seeds that have undergone initial mixing in the Venturi tube 34 are transported through the seed delivery tube 35 to the eccentric mixing chamber 36 for a second mixing. In this example, the seed delivery tube 35 is an L-shaped bent tube, with a lateral length L between the lateral port and the longitudinal centerline. t The longitudinal length H between the longitudinal end of the L-shaped bend and the transverse centerline is 100 mm. t The bend radius R of the seed delivery tube is 200mm and 35mm. t The inner diameter of the seed delivery tube is 43mm; based on the relationship between gas flow rate and delivery speed. Q a The volumetric value of air is preferably 0.050–0.060 m³ / s, va With the fan operating at a wind speed of 28–30 m / s, the inner diameter D of the seed delivery pipe is calculated to be 45–53 mm. In this example, the inner diameter D of the seed delivery pipe is 45 mm. The seeds, which have been initially mixed in the Venturi tube 34, are then transported to the eccentric mixing chamber 36 to complete the second mixing.

[0033] like Figure 4 As shown, the Venturi tube 34 is a key component in the pneumatic collection and distribution device for achieving the initial mixing of seed inhalation and the two-phase flow of gas and seed. It consists of a gas inlet pipe 341, a seed inlet pipe 342, a diffuser pipe 343, and a mixing pipe 344 connected in sequence. The seed inlet pipe 342 is positioned between the gas inlet pipe 341 and the diffuser pipe 343, and is perpendicular to both. The gas inlet pipe 341 has a stepped inner diameter, and its outlet end is a frustum-shaped pipe I, with the inner diameter gradually decreasing from the gas inlet end to the outlet end. The frustum-shaped pipe I at the outlet end intersects with the diffuser pipe 343 and the seed inlet pipe 342. The diffuser pipe 343 is a frustum-shaped pipe II with the inner diameter gradually increasing from the inlet end to the outlet end. The inner diameter D of the mixing pipe 344 is the same as the inner diameter of the seed delivery pipe 35. In this example, the injection angle α of the frustum-shaped pipe I is 60°, the total length L of the Venturi tube 34 is 203 mm, and the diameter d of the seed inlet pipe 342 is... l The length L1 of the diffuser tube 343 is 77 mm, and the diffusion angle β (i.e., the cone apex angle) of the diffuser tube 343 is 13.7°. The length L2 of the mixing tube 344 is 126 mm, and the inner diameter of the mixing tube 344 is the same as the inner diameter D of the seed delivery tube 35, which is 45 mm. To avoid obvious abrupt expansion or contraction at the connection between the outlet of the Venturi tube 34 and the seed delivery tube 35, the airflow outlet end of the diffuser tube 343 of the Venturi tube 34 and the inner diameter of the mixing tube 344 are both 45 mm. Considering the characteristics of small-particle seeds, light weight, and the need for stable seed absorption under mixed sowing conditions, the inner diameter dt of the end of the frustum tube I is 0.40 to 0.50 times the inner diameter D of the seed delivery tube 35. Taking into account the seed absorption negative pressure and local resistance loss, the inner diameter dt of the end of the frustum tube I in this example is 20 mm. The airflow inlet pipe 341 is connected to the fan 31, the seed inlet pipe 342 is connected to the seed box 33, and the mixing pipe 344 is connected to the seed conveying pipe 35. The seeds discharged from the seed discharge main pipe and the high-speed airflow generated by the fan 31 form a two-phase flow of gas and seeds in the diffuser pipe. During operation, based on Bernoulli's principle, the airflow is compressed and its speed increases after passing through the position of the frustum pipe I, and the pressure decreases. The airflow speed reaches its maximum at the contraction point at the end of the frustum pipe I, i.e., the bottom of the seed inlet pipe. A negative pressure is formed at the seed inlet of the diffuser pipe 343, and the two-phase flow of gas and seeds is conveyed to the diffuser pipe 343 and the mixing pipe 344 to complete the mixing.

[0034] like Figure 7As shown, the minimum inner diameter of the corrugated pipe 37 is the same as that of the seed delivery pipe 35, which is 45 mm. The effective length Hp of the corrugated section is 180 mm. After secondary mixing in the eccentric mixing chamber 36, the high-speed gas-seed two-phase flow is further buffered, rectified, and stabilized in the corrugated pipe 37, whose inner wall has a periodic zigzag undulation distribution. This allows the seeds to form a relatively uniform and stable suspended flow state before entering the distributor 38, thereby avoiding uneven distribution at the end due to excessive velocity, local flow deviation, or particle agglomeration. Compared with a smooth straight pipe, the corrugated pipe 37 has a periodic zigzag undulation distribution on its inner wall. When the airflow flows in it, it will be subject to stronger wall disturbance, which will cause the particle trajectory to be moderately randomized. This helps to reduce the local velocity concentration phenomenon remaining at the outlet of the eccentric mixing chamber 36 and improve the uniformity of particle distribution before entering the distributor.

[0035] like Figure 8 As shown, the distributor 38 includes an inlet section 381, a distribution cavity 383, and multiple seed-guiding channels 385. A V-shaped distribution cavity 383 is formed between the inlet section 381 and the multiple seed-guiding channels 385. Each seed-guiding channel 385 has a seed-guiding port 382 at its end. The seed-guiding channels 385 are evenly spaced along the outer periphery of the inlet section 381. Each seed-guiding channel 385 consists of horizontal and vertical sections. The horizontal sections are radially distributed along the circumference of the distribution cavity, and the vertical sections are circumferentially distributed along the inlet section. The axes of the inlet section 381 and the seed-guiding ports 382 are parallel, and the gas and seed phases flow in opposite directions. The top end cap 384 of the V-shaped distribution cavity 383 has a V-shaped angle. The angle is 120°; the inlet section 381 connects to the corrugated pipe 37, and the seed guide port 382 connects to the seed tube of the seeding unit; in this example, the maximum outer diameter D of the distributor 38 is... L The diameter is 341 mm to ensure the symmetry of seed distribution in the circumferential direction. The distributor 38 adopts an axisymmetric structure and has a moderately expanded V-shaped distribution cavity inside. This allows the high-speed gas-seed two-phase flow to enter the distributor 38 from bottom to top, first diffuse and slow down, and then be evenly distributed to each seed guide channel 385. The flow is then output downward to the seeding tube through each seed guide port 382 to improve the flow distribution at each outlet.

[0036] The seed box 33 is equipped with a spiral seed discharge wheel (existing technology) at the seed discharge port, which is driven by a seed discharge motor. The fertilizer box is equipped with a fertilizer discharge device connected to the fertilizer discharge motor at the fertilizer discharge port to achieve precise electronic control adjustment of the seeding amount and fertilizer application amount.

[0037] The seeding unit 5 is an existing purchased product, such as... Figure 9As shown, multiple components are hung side-by-side on the rear beam of the frame 1, including a four-bar linkage contouring mechanism 52, a contouring wheel 51, a contouring spring 521, an adjusting handle 522 (for adjusting the contouring amount), a furrow opener 53, a seeding tube, a covering plate 54, and a pressing wheel 55. The bottom end of the seeding unit 5 is connected to the bottom of the frame 1, and the four-bar linkage contouring mechanism 52, which is connected to the furrow opener 53, is connected to the rear beam of the frame 1. The contouring wheel 51 set on the bottom connecting frame of the seeding unit 5 senses the undulation of the ground surface. Through the cooperation of the four-bar linkage contouring mechanism 52 and the contouring spring 521, the furrow opener 53 connected to it can move up and down with the undulation of the ground surface to maintain a consistent soil penetration depth. The seeding tube is a steel wire hose connecting the seed guide port 382 and the furrow opener 53. The covering plate 54 and the pressing wheel 55 set at the rear of the connecting frame corresponding to the furrow opener 53 of each seeding unit complete the soil covering and pressing operation after sowing.

[0038] The rotary tillage and fertilization unit 4 includes a rotary tillage roller, a fertilizer application pipe 45 positioned above the rotary tillage roller, and a fertilizer tank 42. Multiple fertilizer application pipes are connected to the two side plates of the frame above the rotary tillage roller via mounting plates. One end of each fertilizer application pipe is connected to the fertilizer outlet of the fertilizer tank 42 via a flexible steel wire hose, and the other end is connected to the fertilizer application pipe 45. The rotary tillage roller (existing technology) consists of a rotary tillage shaft 41 and multiple rotary tillage blades 43 spirally arranged along the shaft 41. It applies fertilizer to the soil and mixes it with the soil while simultaneously tilling and loosening it. An integral compaction roller 44 is installed between the rotary tillage roller and the seeder / furrow opener 53 below the frame 1. The integral compaction roller 44 is installed between the two side plates of the frame and is used to compact the tilled soil and provide suitable soil conditions for the subsequent furrowing and sowing operations of the seeder unit 34.

[0039] The seed box 33 is equipped with a spiral seed discharge wheel at the seed discharge port, which can realize continuous and uniform seed discharge and is driven by the seed discharge motor 32. The fertilizer box 42 is equipped with a fertilizer discharge device connected to the fertilizer discharge motor at the fertilizer discharge port, so as to realize precise electronic control adjustment of seeding amount and fertilizer application amount.

[0040] The front end of the frame 1 is equipped with a three-point suspension device 11 for connection with the tractor; the transmission device 2 includes a gearbox 21 and a belt drive assembly 22, the gearbox 21 is mounted on the frame 1, and the transmission principle is as follows: Figure 2As shown, the input end 211 of the transmission shaft of the transmission device 2 is connected to the power output shaft of the tractor, and the output end of the transmission shaft is connected to the input shaft of the gearbox 21. A belt drive assembly 22 is connected to the input shaft of the transmission shaft and the blower 31. That is, pulleys are provided on both the transmission shaft and the input shaft of the blower 31, and belts are fitted on the two pulleys. The blower 31 is driven to run through the belt drive assembly 22. The gearbox 21 is existing technology. In this example, it is composed of a first-stage central bevel gear pair and a first-stage side cylindrical gear transmission. The output shaft 212 of the gearbox 21 is connected to the rotary tillage blade shaft 41 of the rotary tillage and fertilization unit 4, which converts the standard input speed of the tractor's power output shaft into the required output speed of the rotary tillage blade shaft 42, drives it to rotate, and realizes the rotary tillage and soil breaking operation.

[0041] Before operation, small seeds such as hairy vetch and oat seeds are added to their respective seed boxes 33 in the required proportions. During operation, a spiral seed-discharging wheel driven by a seeding motor 32 forces the seeds to flow into the seed-discharging pipe. A high-speed airflow generated by a fan 31 draws the seeds in through a venturi tube 34, forming a two-phase flow of gas and seeds. This flow enters an eccentric mixing chamber 36, where it violently tumbles and vortices to achieve thorough mixing. The mixture is then stabilized through a 180mm long corrugated pipe 37 and finally enters a distributor 38 with multiple seed inlets 382. Figure 3 , Figure 8 As shown, the seeding unit 5 is attached to the rear beam of the frame 1 via a connecting plate. During operation, the front contour wheel 51 is in close contact with the ground. When encountering uneven ground, the four-bar contouring mechanism 52 compresses or releases the contouring spring, keeping the furrow opener 53 in the middle at the set depth. After the seeds fall into the furrow opened by the furrow opener 53 through the seeding tube, the rear covering plate 54 and the compaction wheel 55 immediately complete the covering and compaction.

[0042] The operating method of the forest understory small-particle seed fertilization and mixing planter described in this invention includes: Rotary tillage and fertilizer mixing steps: As the machine moves forward, the rotary tillage blades of the rotary tillage and fertilizer unit 4 break up the compacted soil. At the same time, fertilizer is spread in the working area in front of the rotary tillage blades through the fertilizer discharge and application pipe 45. During the process of breaking up the soil, the rotary tillage blades force the fertilizer to mix with the soil, forming a seedbed with evenly distributed nutrients. Pneumatic seed mixing step: The seed metering motor 32 installed below each seed box 33 drives the spiral seed metering wheel to force the seeds in multiple seed boxes to be discharged. The high-speed airflow generated by the fan 31 draws the seeds in through the venturi tube 34 and transports them to the eccentric mixing chamber 36. The gas-seed two-phase flow is forced to be uniformly mixed under the action of eddy current and turbulence in the eccentric mixing chamber 36, forming a gas-seed two-phase flow with uniform seed distribution. Contour-based precision seeding steps: The uniformly mixed gas-seed two-phase flow enters the distributor 38 after being stabilized by the corrugated pipe 37, and is evenly distributed to the seeding tubes of each seeding unit 5; the contour wheel 51 at the front of the seeding unit 5 senses the undulation of the ground surface, and adjusts the soil penetration depth of the furrow opener 53 in real time through the four-bar contour mechanism 52, so as to accurately guide the seeds into the seed furrow, and complete the soil covering and compaction operations.

[0043] The mixed seeder of this invention is suitable for mixing and sowing small-grained seeds such as hairy vetch and oat seeds in any proportion. This embodiment uses the mixed sowing of hairy vetch and oats as an example. Field trials have verified that the seeder operates smoothly without clogging, and the coefficient of variation for uniformity of discharge rate across rows is 8.83%, significantly lower than the 14.64% for the non-eccentric mixing chamber structure. The mixed sowing effect is good and fully meets agronomic requirements.

[0044] Example 2: This example differs from Example 1 in that the hollow ellipsoidal structure parameters of the eccentric mixing chamber in this example are: pitch angle θ is 30°, semi-major axis a is 50mm, and semi-minor axis b is 25mm. The bend radius R of the seed delivery pipe... t The diameter of the seed delivery tube is 35mm, and the inner diameter D of the seed delivery tube is 47mm; the diameter dt of the frustum-shaped tube I is 0.50 times the inner diameter D of the seed delivery tube, the spray angle α of the frustum-shaped tube I is 40°, and the diffusion angle β of the diffuser tube is 10°; the seed delivery tube is an L-shaped bent tube, and the transverse length L between the transverse port of the L-shaped bent tube and the longitudinal centerline is... t The longitudinal length H between the longitudinal end of the L-shaped bend and the transverse centerline is 80 mm. t The effective length Hp of the corrugated section is 120mm, and the corrugated section is 180mm; the V-shaped angle of the top end cap of the V-shaped distribution cavity of the distributor is... It is 110°.

[0045] Example 3: This example differs from Example 1 in that the hollow ellipsoidal structure parameters of the eccentric mixing chamber in this example are: pitch angle θ is 80°, semi-major axis a is 100mm and semi-minor axis b is 45mm; the bend radius R of the seed delivery pipe... t The diameter of the seed delivery tube is 45 mm, and the inner diameter D of the seed delivery tube is 53 mm; the diameter dt of the frustum-shaped tube I is 0.40 times the inner diameter D of the seed delivery tube, the spray angle α of the frustum-shaped tube I is 50°, and the diffusion angle β of the diffuser tube is 15°; the seed delivery tube is an L-shaped bent tube, and the transverse length L between the transverse port of the L-shaped bent tube and the longitudinal centerline is... t The longitudinal length H between the longitudinal end of the L-shaped bend and the transverse centerline is 90 mm. t The effective length Hp of the corrugated section is 150mm, and the corrugated section is 190mm; the V-shaped angle of the top end cap of the V-shaped distribution cavity of the distributor is... It is 105°.

[0046] The parameter values ​​are determined comprehensively based on differences in seed size, shape, and density, the mixing ratio, the seeding rate, the number of rows, the fan conveying capacity, and the installation space of the equipment. Example 1 shows the preferred parameters under conventional mixed sowing conditions of hairy vetch and oats; Example 2 is suitable for working conditions with limited installation space, small seeding rates, and requirements for low-resistance and stable conveying; Example 3 is suitable for working conditions with large seeding rates, multiple rows, significant differences in seed properties, and requirements for enhanced mixing uniformity.

[0047] The parts not described in detail in this application are all existing conventional technologies and will not be elaborated here.

[0048] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. A forest understory small-particle seed fertilization and mixing machine, characterized in that: The machine includes a frame and its mounted transmission device, rotary tiller / fertilizer unit, seeder unit, and pneumatic collection and dispensing device. The input end of the transmission device is connected to the tractor power, and the output ends are connected to the rotary tiller shaft of the rotary tiller / fertilizer unit and the blower of the pneumatic collection and dispensing device, respectively. There are multiple seeders arranged side by side according to row spacing. The pneumatic collection and dispensing device includes seed boxes, a blower, an eccentric mixing chamber, and a distributor. Multiple seed boxes are set according to seed type. The seed dispensing pipes of various boxes are connected to form a seed dispensing main pipe, which is connected to the air supply pipe of the blower. The air supply pipe passes through a Venturi tube in sequence. The seed delivery pipe is connected to the eccentric mixing chamber, which is connected to the distributor via a corrugated pipe. The distributor has seed inlets corresponding to the number of seeding units, which are connected to the seeding tubes of each seeding unit. Seeds fall freely from the seed metering manifold into the venturi tube, where they mix with the high-speed airflow generated by the fan to form a two-phase flow of air and seeds. The mixture is then transported to the eccentric mixing chamber through the seed delivery pipe connected to the venturi tube, where the seeds and airflow are fully and evenly mixed. After being pressurized and mixed by the corrugated pipe, the mixture enters the distributor and is evenly distributed before being sown through the seeding tubes of the seeding units.

2. The forest understory small-particle seed fertilization and mixing machine according to claim 1, characterized in that: The eccentric mixing chamber is an inclined hollow ellipsoidal structure, consisting of an ellipsoid and transition sections connecting its two ends. The two transition sections are tangentially connected to the outer side of the ellipsoid and are connected to the seed delivery pipe and the corrugated pipe through the transition sections, so that the seed delivery pipe and the corrugated pipe are arranged in parallel and staggered. After the gas-seed two-phase flow enters the eccentric mixing chamber, it forms a rotational tendency under the action of the tangential velocity component, which enhances the lateral migration of particles and local vortex mixing. The inclined asymmetric hollow ellipsoidal structure induces a redistribution of the airflow velocity field and pressure field, so that the seeds are more fully remixed before entering the corrugated pipe.

3. The forest understory small-particle seed fertilization and mixing machine according to claim 2, characterized in that: The hollow ellipsoidal structure parameters of the eccentric mixing chamber are: pitch angle θ is 30~80°, semi-major axis a is 50~100mm and semi-minor axis b is 25~45mm, wherein the pitch angle θ is the angle between the major axis and the y-axis of the mixing chamber.

4. The forest understory small-particle seed fertilization and mixing machine according to claim 1, characterized in that: The Venturi tube consists of an airflow inlet tube, a seed inlet tube, a diffuser tube, and a mixing tube connected in sequence. The seed inlet tube is positioned between the airflow inlet tube and the diffuser tube, and is perpendicular to both. The airflow inlet tube has a stepped inner diameter, and its outlet end is a frustoconical tube I, with its inner diameter gradually decreasing from the airflow inlet end to the outlet end. The frustoconical tube I at the outlet end intersects with the diffuser tube and the seed inlet tube. The diffuser is a frustoconical tube II, with its inner diameter gradually increasing from the inlet end to the outlet end. The mixing tube has the same inner diameter as the seed delivery tube. The diameter dt of the frustoconical tube I is 0.40 to 0.50 times the inner diameter D of the seed delivery tube. The injection angle α of the frustum-shaped tube I is 40–60°, and the diffusion angle β of the diffuser tube is 10–15°. The airflow inlet pipe is connected to the fan, the seed inlet pipe is connected to the seed box, and the mixing pipe is connected to the seed conveying pipe. The seeds discharged from the seed discharge main pipe and the high-speed airflow generated by the fan form a two-phase flow of gas and seed in the diffuser tube. After being compressed at the position of the frustum-shaped tube I, the speed increases and the pressure decreases. The airflow speed reaches its maximum at the contraction point at the end of the frustum-shaped tube I, and a negative pressure is formed at the seed inlet of the diffuser tube, which transports the two-phase flow of gas and seed to the diffuser tube and the mixing tube to complete the mixing.

5. The forest understory small-particle seed fertilization and mixing machine according to claim 1, characterized in that: The seed delivery tube is an L-shaped bent tube, and the lateral length L between the lateral end of the L-shaped bent tube and the longitudinal centerline is... t The longitudinal length H between the longitudinal end of the L-shaped bend and the transverse centerline is 80–100 mm. t The bend radius R of the seed delivery tube is 180-200mm. t The diameter of the seed delivery tube is 35-45 mm, and the inner diameter D of the seed delivery tube is 45-53 mm. The seeds that have been initially mixed in the Venturi tube are then transported to the eccentric mixing chamber to complete the second mixing.

6. The forest understory small-particle seed fertilization and mixing machine according to claim 1, characterized in that: The minimum inner diameter of the corrugated tube is the same as the inner diameter of the seed delivery tube, and the effective length Hp of the corrugated section is 120~180mm. After the high-speed gas-seed two-phase flow is mixed twice in the eccentric mixing chamber, it is further buffered, rectified and stabilized in the corrugated tube with periodic zigzag distribution on the inner wall, so that the seeds form a relatively uniform and stable suspended flow state before entering the distributor.

7. The forest understory small-particle seed fertilization and mixing machine according to claim 1, characterized in that: The distributor includes an inlet section, a distribution cavity, and multiple seed-guiding channels. A V-shaped distribution cavity is formed between the inlet section and the seed-guiding channels. Each seed-guiding channel has a seed-guiding port at its end. The seed-guiding channels are evenly spaced along the outer circumference of the inlet section and consist of horizontal and vertical sections. The horizontal sections are radially distributed along the circumference of the distribution cavity, and the vertical sections are circumferentially distributed along the inlet section. The axes of the inlet section and the seed-guiding ports are parallel, and the gas and seed phases flow in opposite directions. The V-shaped angle of the top end cap of the V-shaped distribution cavity is... The angle is 105-120°, the inlet section is connected to the corrugated pipe, and the seed guide port is connected to the seed tube of the seeding unit.

8. The forest understory small-particle seed fertilization and mixing machine according to claim 1, characterized in that: The rotary tillage and fertilization unit includes a rotary tillage roller, a fertilizer application pipe and a fertilizer box set above the rotary tillage roller. There are multiple fertilizer application pipes, which are connected to the two side plates of the frame above the front of the rotary tillage roller through the mounting plate. One end of the fertilizer application pipe is connected to the fertilizer discharge port of the fertilizer box through a steel wire hose, and the other end passes through the mounting plate corresponding to the rotary tillage roller. While rotary tilling and loosening the soil, fertilizer is applied into the soil and mixed with the soil.

9. The forest understory small-particle seed fertilization and mixing machine according to claim 1, characterized in that: An integral compaction roller is installed between the rotary tiller and the seeder / furrow opener below the frame. The integral compaction roller is installed between the two side plates of the frame to compact the soil after rotary tillage.

10. The operating method of the forest understory small-particle seed fertilization and mixing planter as described in any one of claims 1-9, characterized in that: include: Rotary tillage and fertilizer mixing steps: As the machine moves forward, the rotary tillage blades of the rotary tillage and fertilizer application unit break up the compacted soil. At the same time, fertilizer is spread in the area in front of the rotary tillage blades through the fertilizer application pipe. During the process of breaking up the soil, the rotary tillage blades force the fertilizer to mix with the soil, forming a seedbed with evenly distributed nutrients. Pneumatic mixing process: The seed metering motor drives the spiral seed metering wheel to force the seeds out of multiple seed boxes. The high-speed airflow generated by the fan draws the seeds in through the Venturi tube and transports them to the eccentric mixing chamber. The gas-seed two-phase flow is forced to mix evenly under the action of eddies and turbulence in the eccentric mixing chamber, forming a gas-seed two-phase flow with uniform seed distribution. Contour-based precision seeding steps: The uniformly mixed gas-seed two-phase flow is stabilized through a corrugated pipe and then enters the distributor, where it is evenly distributed to the seeding tubes of each seeding unit, precisely guiding the seeds into the seed furrow, and completing the soil covering and compaction operations.

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