An air-assisted seed metering system high-throughput seed mixing device

Abstract

The application relates to a high-throughput seed mixing device of an air-assisted seed metering system, which is an overall structure composed of a seed dropping section, an airflow accelerating section, a seed feeding section, a seed mixing section and a diffusion section. The seed feeding section is fixedly matched with the seed dropping section at the top and fixedly matched with the airflow accelerating section pipe at the bottom. The inclined surface terminal of the seed outlet of the seed feeding section is coplanar with the airflow outlet of the airflow accelerating section and is fixedly matched with the seed mixing section. The other end of the seed mixing section is fixedly matched with the diffusion section. The design is based on a sudden expansion pipeline structure. The airflow flowing through the structure arrangement mode of sudden expansion and seed mixing lag can form a negative pressure area above the seed feeding section. The seeds in the area enter the seed conveying pipeline under the joint action of the self gravity and the suction force generated by the pressure difference, and the problems of seed blockage and reflux during operation caused by the inconsistent acceleration state of the seed group entering the throat pipe, the mismatch between the seed quantity and the cross-sectional area of the throat pipe terminal and the like under the high-speed large seeding quantity and wide seeding width operation condition of the traditional Venturi seed mixing device are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seeding in agricultural machinery, in particular to a high-throughput mixing device of a pneumatic seed metering system. BACKGROUND

[0002] The pneumatic seed metering device uses high-speed airflow as the main carrier to carry seeds, has the advantages of strong adaptability and no seed damage. The high-throughput pneumatic seed metering device can be used with a large horsepower tractor to realize high-speed seeding operation. Compared with mechanical and air-suction seed metering devices, the pneumatic seed metering device has more stable working performance and is more likely to realize high-speed seeding of crops such as rapeseed and wheat.

[0003] The pneumatic seed metering device is composed of a seed box, a seed supply device, a mixing device, a distribution device, and a seed conveying pipe. The rotation speed of the seed supply device or the seed supply wheel is adjusted to control the seeding rate to adapt to different seeding speeds. The mixing device is a key component for the smooth delivery of seeds, as it is the area where seeds are rapidly energized by high-speed airflow. The Venturi tube is the most common mixing device at present because of its unique accelerating effect. The traditional Venturi mixing device can promote the mixing of airflow and seeds at the throat by the accelerating effect of the converging section and carry the seeds for subsequent delivery. However, when the seeding rate is high, the Venturi mixing device may cause problems such as seed retention, backflow, and blockage in the mixing device. The reason is that the seed flow through the mixing device is large, and the accelerating effect of the seeds at the front end and the terminal end of the Venturi accelerating throat is inconsistent, causing seed collision, rebound, and blockage. The traditional Venturi mixing device has problems such as blockage, backflow, and reflux when used for high-speed, high-seeding-rate, and wide-seeding-width seeding operations, which affects the stability of the seeding rate and the uniformity of subsequent seed distribution, leading to a decrease in actual seeding rate and yield, and ultimately failing to complete high-speed seeding operations. Increasing the diameter of the seed conveying pipe and the cross-sectional area of the Venturi accelerating throat can reduce the problems of backflow and blockage to some extent. However, according to the continuity equation, increasing the diameter of the seed conveying pipe increases the required airflow velocity by an exponential factor, which increases the power consumption of the fan or reduces the airflow velocity, affecting the seed distribution effect, and does not meet the design requirements of agricultural machinery. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a high-throughput mixing device of a pneumatic seed metering system to solve the above problems and requirements.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] The application discloses a high-throughput seed mixing device of an air-assisted seed metering system, which comprises a seed dropping section, an airflow accelerating section, a seed feeding section, a seed mixing section and a diffusion section.

[0007] Further, the inner diameter of the airflow inlet of the airflow accelerating section is consistent with the inner diameter of the outlet of the diffusion section.

[0008] Further, the inclined angle of the lower inclined surface of the seed feeding section outlet is equal to 30 degrees.

[0009] Further, the horizontal projection length of the lower inclined surface of the seed feeding section outlet is 0.35 to 0.5 times the inner diameter of the seed feeding section inlet.

[0010] Further, the connection between the seed mixing section and the seed feeding section is a bending end, the gap between the lower end of the lower inclined surface of the seed feeding section outlet and the bending end forms the seed feeding section outlet, and the vertical height of the seed feeding section outlet is 0.35 to 0.5 times the inner diameter of the seed mixing section.

[0011] Further, the longitudinal section area of the seed mixing section is the sum of the longitudinal section area of the airflow outlet of the airflow accelerating section and the longitudinal section area of the seed outlet of the seed feeding section.

[0012] Further, the inner diameter of the diffusion section outlet is the same as the inner diameter of the external seed conveying pipeline.

[0013] Further, the equivalent diameter of the seed mixing section is 0.4 times the inner diameter of the diffusion section outlet.

[0014] Further, the lengths of the airflow accelerating section, the seed mixing section and the diffusion section are the same.

[0015] Compared with the prior art, the application has the following advantages:

[0016] 1. The high-throughput seed mixing device of the air-assisted seed metering system can realize high-speed sowing operation of crops such as wheat and oilseed rape.

[0017] 2. The high-throughput seed mixing device of the air-assisted seed metering system is arranged by setting the sudden expansion structure and the seed mixing section at the rear end of the seed feeding section, a pressure difference is formed in the seed dropping area to generate suction, the negative pressure area is larger and more stable compared with the prior art structure, and seeds enter the seed conveying pipeline under the joint action of gravity and negative pressure suction.

[0018] 3, The high-throughput mixing device of the air-assisted seed metering system of the application avoids the problems of blockage and backflow caused by the mismatch between the seed quantity and the cross-sectional area of the throat pipe end, the inconsistent seed acceleration at the front and rear ends of the throat pipe, etc. during high-speed seeding operation, and improves the quality of seeding operation.

[0019] 4, The high-throughput mixing device of the air-assisted seed metering system of the application has a simple structure, a small size, and is easy to install, avoids the problem of increasing the pipe diameter to increase power consumption, requires small wind pressure for work, and can greatly reduce power consumption during machine operation. Compared with the existing structure, the required fan power consumption can be reduced by more than 3 times.

[0020] The application will be described in detail below in conjunction with the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a three-dimensional structure diagram of the high-throughput mixing device of the air-assisted seed metering system of the application;

[0022] Figure 2 is a front cross-sectional view of the overall structure of the application;

[0023] Figure 3 is a seed falling section in Figure 1

[0024] Figure 4 is a gas flow acceleration section in Figure 1

[0025] Figure 5 is a seed feeding section in Figure 1

[0026] Figure 6 is a mixing section in Figure 1

[0027] Figure 7 is a diffusion section in Figure 1

[0028] Figure 8 is a structure diagram of the application applied to a seed conveying system; Figure 1

[0029] is a pressure distribution diagram of the internal gas flow field of the high-throughput mixing device of the application. Figure 9 Wherein: 1-seed falling section; 2-gas flow acceleration section; 3-seed feeding section; 4-mixing section; 5-diffusion section; 6-seed conveying pipe; 7-distribution device; 8-seed guide pipe; I-gas flow acceleration zone; II-seed feeding zone; III-mixing zone; IV-diffusion zone.

[0030] DETAILED DESCRIPTION

[0031] ​​​​​​The principles and characteristics of the present application are described below in conjunction with the accompanying drawings, which are only used to explain the present application and not to limit the scope of the present application.

[0032] A high-throughput seed mixing device of an air-assisted seed metering system comprises a seed dropping section 1, an airflow accelerating section 2, a seed feeding section 3, a seed mixing section 4 and a seed diffusing section 5, the seed feeding section 3 is arranged directly below the outlet of the seed dropping section 1, the outlet of the airflow accelerating section 2 is a tapered cone, the inclined surface below the outlet of the seed feeding section 3 is fixed vertically with the tapered cone of the airflow accelerating section 2, the terminal longitudinal section of the inclined surface below the outlet of the seed feeding section 3 is coplanar with the airflow outlet of the airflow accelerating section 2, the outlet of the seed feeding section 3 is perpendicular to and communicates with the inlet of the seed mixing section 4, the seed mixing section 4 is parallel to and communicates with the axis of the airflow accelerating section 2, the outlet of the seed mixing section 4 is parallel to and communicates with the inlet of the seed diffusing section 5, the outlet area of the seed diffusing section 5 is larger than the inlet area, and the outlet is connected to an external seed conveying pipeline 6, and the external seed conveying pipeline 6 is connected to an external seed metering device.

[0033] As an embodiment, the inner diameter of the airflow inlet of the airflow accelerating section 2 is consistent with the inner diameter of the outlet of the seed diffusing section 5.

[0034] As an embodiment, the inclined angle of the inclined surface below the outlet of the seed feeding section 3 is equal to 30°, and the inner inclined surface is larger than the natural rest angle of the seed to avoid the accumulation of the seed on the inclined surface.

[0035] As an embodiment, the horizontal projection length of the inclined surface below the outlet of the seed feeding section 3 is 0.35 to 0.5 times the total length of the seed feeding section 3.

[0036] As an embodiment, the connection between the seed mixing section 4 and the seed feeding section 3 is a bending end, the gap between the lower end of the inclined surface below the outlet of the seed feeding section 3 and the bending end forms the outlet of the seed feeding section 3, and the vertical height of the outlet of the seed feeding section 3 is 0.35 to 0.5 times the inner diameter of the seed mixing section 4.

[0037] As an embodiment, the longitudinal section area of the seed mixing section 4 is the sum of the longitudinal section area of the airflow outlet of the airflow accelerating section 2 and the longitudinal section area of the seed outlet of the seed feeding section 3.

[0038] As an embodiment, the inner diameter of the outlet of the seed diffusing section 5 is the same as the inner diameter of the external seed conveying pipeline.

[0039] As an embodiment, the equivalent diameter of the seed mixing section 4 is 0.4 times the inner diameter of the outlet of the seed diffusing section 5.

[0040] As an embodiment, the lengths of the airflow accelerating section 2, the seed mixing section 4 and the seed diffusing section 5 are the same.

[0041] The working principle of the present application is as follows:

[0042] The seed supply device in the pneumatic seed metering system moves the seeds to the seed dropping section, and the seeds enter the seed dropping port under the action of gravity. At this time, the airflow acceleration section accelerates the airflow delivered by the fan through the airflow acceleration zone, and the airflow enters the mixing section through the seed inlet zone. According to Bernoulli's principle, the airflow velocity in the seed inlet zone and the mixing section is large, and the pressure is small. A negative pressure area is formed at the inclined surface of the seed inlet section due to the sudden expansion of the pipeline. The seeds enter the mixing section and mix with the airflow under the combined action of gravity and the suction force generated by the pressure difference, and then the seeds in high-speed motion are sent into the seed conveying pipe through the diffusion section, and the subsequent distribution device carries out seed metering.

[0043] As Figure 9 The working gas pressure flow field distribution diagram of the application is shown. In the DEM-CFD gas-solid coupling simulation test of the application, the wheat seed sowing amount can reach 150g / s, and there is no problem of seed blockage, backflow and the like. In the bench test, the sowing amount of the wheat seeds can reach 150g / s, and there is no problem of seed blockage, backflow and the like, which has met the sowing operation requirements of 12km / h of wheat and rapeseed.

[0044] Example 1

[0045] This example is completed in the precision seed metering laboratory of Central China Agricultural University. The test object is Zhengmai 9023, and the test device is a pneumatic seed metering device provided with a high-flux seed mixing device. In order to meet the requirements of the high-speed sowing machine of the pneumatic sowing machine on the mixing flux in the mixing device under different operation speeds, the theoretical seed supply amount of the seed supply device is set to 40, 60, 80, 100 and 120g per second.

[0046]

[0047]

[0048] Comparative Example 2

[0049] This example is completed in the precision seed metering laboratory of Central China Agricultural University. The test object is Zhengmai 9023, and the test device is a pneumatic seed metering device provided with a high-flux seed mixing device. In order to meet the requirements of the high-speed sowing machine of the pneumatic sowing machine on the mixing flux in the mixing device under different operation speeds, the theoretical seed supply amount of the seed supply device is set to 40, 60, 80, 100 and 120g per second.

[0050]

[0051] From the above examples, it can be seen that the ordinary Venturi mixing device without the abrupt expansion structure will have backflow and even clogging phenomenon when the sowing amount exceeds a certain amount, and the variation coefficient of the uniformity of each row is higher than 3.9% when the sowing amount exceeds a certain range, which does not reach the operation qualified standard of the air-assisted seed metering device; the structure arrangement of setting the abrupt expansion and mixing lag adopted by the present application can improve the mixing sowing amount to 118.8 g / s, and there is no backflow, clogging and other problems, the variation coefficient of the uniformity of each row is lower than 3.9%, and the variation coefficient of the stability of the total sowing amount is lower than 1.3%, which can meet the operation speed of 12 km / h.

[0052] The above is an example of the best embodiment of the present application, wherein the parts not described in detail are all the common knowledge of ordinary skilled in the art. The protection scope of the present application is subject to the content of the claims, and any equivalent transformation based on the technical inspiration of the present application is also within the protection scope of the present application.

Claims

1. A high-throughput seed mixing device for an air-pneumatic seed metering system, characterized in that, It includes a seed dropping section (1), an airflow acceleration section (2), a seed entry section (3), a seed mixing section (4), and a diffusion section (5). The seed entry section (3) is located directly below the outlet of the seed dropping section (1). The outlet of the airflow acceleration section (2) is a tapered cone. The inclined surface below the outlet of the seed entry section (3) is fixed perpendicularly to the tapered cone of the airflow acceleration section (2). The longitudinal section at the end of the inclined surface below the seed entry section (3) is coplanar with the airflow outlet of the airflow acceleration section (2). The outlet of the seed entry section (3) is perpendicular to and connected to the inlet of the seed mixing section (4). The axis of the seed mixing section (4) is parallel to and connected to the axis of the airflow acceleration section (2). The outlet of the seed mixing section (4) is parallel to and connected to the inlet of the diffusion section (5). The outlet area of ​​the diffusion section (5) is larger than the inlet area, and the outlet is used to connect to an external seed delivery pipe (6). The external seed delivery pipe (6) is used to connect to an external distribution device. The inclination angle of the inner inclined surface below the outlet of the seed entry section (3) is equal to 30°. The horizontal projection length of the inclined surface below the outlet of the seed inlet section (3) is 0.35 to 0.5 times the total length of the seed inlet section (3); the connection between the mixed seed section (4) and the seed inlet section (3) forms a bend, and the gap between the lower end of the inclined surface below the outlet of the seed inlet section (3) and the bend forms the outlet of the seed inlet section (3); the vertical height of the outlet of the seed inlet section (3) is 0.35 to 0.5 times the inner diameter of the mixed seed section (4); the longitudinal cross-sectional area of ​​the mixed seed section (4) is the sum of the longitudinal cross-sectional area of ​​the airflow outlet of the airflow acceleration section (2) and the longitudinal cross-sectional area of ​​the seed outlet of the seed inlet section (3).

2. The high-throughput seed mixing device for the pneumatic seed metering system according to claim 1, characterized in that, The inner diameter of the airflow inlet of the airflow acceleration section (2) is the same as the inner diameter of the outlet of the diffusion section (5).

3. The high-throughput seed mixing device for the pneumatic seed metering system according to claim 1, characterized in that, The inner diameter of the outlet of the diffusion section (5) is the same as the inner diameter of the external seed delivery pipeline.

4. The high-throughput seed mixing device for the pneumatic seed metering system according to claim 1, characterized in that, The equivalent diameter of the hybrid section (4) is 0.4 times the inner diameter of the outlet of the diffusion section (5).

5. The high-throughput mixed seed device for the pneumatic seed metering system according to claim 1, characterized in that, The airflow acceleration section (2), the hybridization section (4), and the diffusion section (5) are of the same length.

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