CN108745889B

CN108745889B - Agricultural seed screening device and method

Info

Publication number: CN108745889B
Application number: CN201810563221.8A
Authority: CN
Inventors: 高元琴
Original assignee: Shaoxing Xinyao Mechanical And Electrical Technology Co ltd
Current assignee: Shizhu Tujia Autonomous County Balong Agricultural Development Co.,Ltd.
Priority date: 2018-06-04
Filing date: 2018-06-04
Publication date: 2020-08-21
Anticipated expiration: 2038-06-04
Also published as: CN108745889A

Abstract

The invention discloses an agricultural seed screening device, which comprises a winnowing device, two air screening devices and a water screening device, wherein the winnowing device comprises a shell, a winnowing fan is arranged on the right side of the shell, a baffle is arranged in the shell, a channel is arranged on the left side of the baffle, and the channel is connected with a collecting chamber; the air screen device comprises a shell, and a collecting bin is arranged at the lower part of the shell; an inclined screen is arranged in the shell, and a discharge hopper chamber is arranged at the left lower part of the screen; an air screen fan is arranged on the right side of the shell; the water separation device comprises a water chamber, an inlet pipeline is arranged on the left side of the top of the water chamber, an overflow chamber is arranged on the right upper part of the outer side of the water chamber, and a blocking net is arranged in the middle of the overflow chamber; the invention also designs an agricultural seed screening method which sequentially comprises a wind separation process, a two-wind screening process and a water separation process. The invention adopts a method of combining three screening modes of air separation, net type screening and water washing, has more guaranteed screening effect and high working efficiency, and is beneficial to the screening work of large-batch agricultural seeds.

Description

Agricultural seed screening device and method

Technical Field

The invention relates to agricultural equipment, in particular to an agricultural seed screening device and method.

Background

The agricultural seeds are easy to be mixed with impurities such as empty grains, shriveled grains, dust, seed shells, straw shells, weeds and the like in the collection process, and the impurities need to be screened out to retain normal agricultural seeds.

Generally, the size, the weight and the particle size of impurities are different from those of agricultural seeds, so that in the actual production process, a wind separation method according to different weights, a net type screening method according to different particle sizes and a water separation method according to different floatability are adopted, and the various methods have advantages and disadvantages and have different screening effects and efficiencies, so that the agricultural seed screening device used in combination can be invented to improve the screening effect and efficiency.

Disclosure of Invention

The purpose of the invention is: provides an agricultural seed screening device with good screening effect.

The scheme of the invention is as follows: the utility model provides an agricultural seed sieving mechanism, includes a wind selector, two wind sieve devices and a water selection device, two wind sieve devices one are located upper portion, another are located the lower part, its characterized in that:

the winnowing device comprises a shell, wherein the upper part of the shell is provided with a feeding hole, the bottom of the shell is provided with a discharging hole, the right side of the shell is provided with a winnowing fan, the left side of the shell is provided with an air outlet with a filter screen, a baffle is eccentrically arranged in the shell towards the left side, the left side of the baffle is provided with a channel extending to the outside, the channel is connected with a collecting chamber, and the collecting chamber is provided with an air outlet;

the air screening device comprises a shell, a feed hopper is arranged at the top of the left side of the shell, a collection bin is arranged at the lower part of the shell, and an air outlet window with a filter screen is arranged on the collection bin; a discharge pipe is arranged at the lower part of the right side of the machine shell, an inclined screen is arranged in the machine shell, and a discharge hopper chamber connected with the collection bin is arranged at the lower left part of the screen; the air screening machine is arranged on the right side of the shell and connected with an air outlet pipe, the air outlet pipe is provided with an upper air outlet and a lower air outlet which are communicated with the shell, an upper guide plate and a lower guide plate are arranged above the right side of the screen, the upper guide plate is positioned above the upper air outlet, the lower guide plate is positioned above the lower air outlet, the left ends of the upper guide plate and the lower guide plate are both upwards warped, the distance between the upwards warped part and the screen is larger, and an exhaust pipe is arranged at the top of the right side of the shell;

the water separation device comprises a water chamber, an inlet pipeline is arranged on the left side of the top of the water chamber, an overflow chamber is arranged on the right upper part of the outer side of the water chamber, a blocking net is arranged in the middle of the overflow chamber, an outlet pipe is arranged on the lower part of the overflow chamber, and a valve is arranged on the outlet pipe; the water chamber is communicated with the overflow chamber through an overflow port; the bottom of the water chamber is an inclined plane with a higher left part and a lower right part, the right bottom of the water chamber is provided with an outlet pipeline, and the outlet pipeline is provided with a valve; the lower part in the water chamber is provided with an inverted V-shaped guide plate, the left lower part of the water chamber is provided with an inner circulating pipe, a pipe orifice at the upper part of the inner circulating pipe is positioned above the inverted V-shaped guide plate, a pipe orifice at the lower part of the inner circulating pipe is positioned below the inverted V-shaped guide plate, the inner circulating pipe is provided with a forward pump and a valve, the inner circulating pipe is also provided with a bypass, and the bypass is provided with a reverse pump and a valve; a water feeding pipe is inserted into the water chamber, a water feeding valve is arranged on the water feeding pipe, a transverse distribution pipe is arranged at the bottom of the water feeding pipe, and a plurality of water outlets lower than the overflow port are arranged at the upper part of the transverse distribution pipe;

the discharge port of the air separation device is communicated with the feed hopper of the air screen device positioned at the upper part; the discharge pipe of the air screen device positioned at the upper part is connected with the feed hopper of the air screen device positioned at the lower part through a communicating pipe with an open top; a discharge pipe of the air screen device positioned at the lower part is communicated with an inlet pipeline of the water separation device; the inclination angle of the screen of the air screen device positioned at the upper part is larger than that of the screen of the air screen device positioned at the lower part.

The invention also designs an agricultural seed screening method, which adopts the agricultural seed screening device and is characterized by sequentially comprising a wind separation process, a two-pass wind screen process and a water separation process;

the winnowing process comprises the following steps: the seeds to be screened enter an air separation device, lighter shrivelled seeds, seed shells, dust and weeds are blown to the left side by an air separation fan and collected in a collection chamber, and other seeds to be screened fall from the lower part;

the air screening process comprises the following steps: the seeds to be screened enter an air screening device, the seeds to be screened fall along a screen, an air screening fan blows air to the direction of the screen, the seeds to be screened fall against the air, small particles in the seeds to be screened fall in a collecting bin at the left lower part of the screen, and normal seeds are discharged from a discharging pipe of the air screening device;

the water separation process comprises the following steps: when seeds to be screened enter the water chamber, the water surface in the water chamber is lower than the overflow port by one centimeter, when the seeds to be screened enter the water chamber, the reverse pump works to disturb the water in the water chamber, so that floatable impurities contained in the seeds to be screened float on the water surface, normal seeds sink, after all the seeds to be screened enter the water chamber and settle for five minutes, the forward pump works, the water adding valve is opened to enable the liquid level to be full, the floatable impurities floating on the liquid level flow out from the overflow port into the overflow chamber, the valve on the outflow pipe is opened, the floatable impurities are filtered on the blocking net, the forward pump is stopped after the overflow lasts for five minutes, the valve on the outlet pipeline is opened to discharge the screened seeds, and then the water adding is stopped.

Compared with the prior art, the invention has the beneficial effects that: the method combining the air separation mode, the net type screening mode and the water washing mode is adopted, the screening effect is more guaranteed, the three devices are sequentially arranged from top to bottom, the three processes are sequentially completed, the working efficiency is high, the screening work of large-batch agricultural seeds is facilitated, and the practicability is high.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic view of the construction of an agricultural seed screening apparatus described in example 1;

fig. 2 is a schematic structural view of the air separation device of the present invention;

FIG. 3 is a schematic structural view of the air screen apparatus of the present invention;

FIG. 4 is a schematic structural diagram of a water separation device according to the present invention;

FIG. 5 is a schematic view of the agricultural seed screening apparatus described in example 2;

reference parts in the drawings:

the air separation device comprises an air separation device 1, a shell 101, a discharge hole 102, an air separation fan 103, an air outlet 104, a baffle 105, a channel 106 and a collection chamber 107;

the wind screen device 2, a shell 201, a feed hopper 202, a collection bin 203, a discharge pipe 204, a screen 205, a wind screen fan 206, an upper guide plate 207, a lower guide plate 208, a wind outlet pipe 209, an upturned part 210, a gas outlet pipe 211, a wind outlet window 213, a wind screen device,

The water separation device 3, a water chamber 301, an inlet pipeline 302, an overflow chamber 303, a barrier net 304, an outflow pipe 305, an overflow port 306, an outlet pipeline 307, an inverted V-shaped guide plate 308, an internal circulation pipe 309, a bypass 310, a water adding pipe 311, a transverse distribution pipe 312, a water outlet 313, a forward pump 314 and a reverse pump 315.

Detailed Description

The invention is further described by way of example with reference to the accompanying drawings.

Example 1:

as shown in fig. 1, the agricultural seed screening device described in this embodiment includes an air separation device 1, two air screen devices 2 and a water separation device 3, where the two air screen devices 2 are located at an upper portion and a lower portion, and is characterized in that:

as shown in fig. 2, the air separation device 1 includes a casing 101, a feed inlet is arranged at the upper part of the casing 101, a discharge outlet 102 is arranged at the bottom of the casing 101, an air separation fan 103 is arranged at the right side of the casing 101, an air outlet 104 with a filter screen is arranged at the left side of the casing 101, a baffle 105 is eccentrically arranged near the left side in the casing 101, a channel 106 extending to the outside is arranged at the left side of the baffle 105, the channel 106 is connected with a collection chamber 107, an air outlet window with a filter screen is arranged on the collection chamber 107, the air outlet window is standard that air can penetrate through the air but the filtered impurities cannot penetrate through;

as shown in fig. 3, the air sieving device 2 includes a casing 201, a feed hopper 202 is disposed at the top of the left side of the casing 201, a collection bin 203 is disposed at the lower part of the casing 201, and an air outlet window 213 with a filter screen is disposed on the collection bin 203; a discharge pipe 204 is arranged at the lower part of the right side of the machine shell 201, an inclined screen 205 is arranged in the machine shell 201, and a discharge hopper chamber 214 connected with the collection bin 203 is arranged at the lower left part of the screen 205; be equipped with wind sieve fan 206 on casing 201 right side, wind sieve fan 206 is connected with out tuber pipe 209, it has last air outlet and lower air outlet with casing 201 intercommunication to go out tuber pipe 209, be equipped with deflector 207 and lower deflector 208 in screen 205 upper right side, it is located the air outlet top to go up deflector 207, lower deflector 208 is located air outlet top down, the left end of going up deflector 207 and lower deflector 208 all is upturned and this upturned part 210 is more up more with screen 205's interval big more, upturned part 210 has two effects: firstly, the wind at the air outlet is guided upwards in an inclined way, so that the wind direction is opposite to the falling direction of the seeds, the seeds can be billowed in the falling process, the seeds are prevented from falling too fast and have enough time to contact with the screen, and the fine seeds are easier to fall through the screen; secondly, the distance between the upturned part 210 and the screen 205 is larger, so that the upturned part is prevented from falling onto the two guide plates when the seeds are blocked by reversely blown wind in the process of sliding downwards in an inclined mode, the exhaust pipe 211 is arranged at the top of the right side of the casing 201, redundant wind can be discharged from the exhaust pipe 211, and the filter screen is preferably arranged on the exhaust pipe 211 to prevent sundries from flying out; the fine seeds collected in the collection bin 203 are cleaned regularly;

as shown in fig. 4, the water separation device 3 comprises a water chamber 301, an inlet pipe 302 is arranged on the left side of the top of the water chamber 301, an overflow chamber 303 is arranged on the right upper part of the outer side of the water chamber 301, a barrier net 304 is arranged in the middle of the overflow chamber 303, an outlet pipe 305 is arranged on the lower part of the overflow chamber 303, and a valve is arranged on the outlet pipe 305; the water chamber 301 is communicated with the overflow chamber 303 through an overflow port 306; the bottom of the water chamber 301 is an inclined plane with a higher left part and a lower right part, the right bottom of the water chamber 301 is provided with an outlet pipeline 307, the outlet pipeline 307 is provided with a valve, the outlet pipeline 307 can also be provided with a delivery pump, and screened seeds are pumped onto an external filter screen to be filtered and dried, and then are dried to be used as a finished product; an inverted V-shaped guide plate 308 is arranged at the lower part in the water chamber 301, and the sunk seeds can better fall onto the inclined plane at the bottom under the guide of the inverted V-shaped guide plate 308; an inner circulating pipe 309 is arranged at the left lower part of the water chamber 301, a pipe orifice at the upper part of the inner circulating pipe 309 is positioned above the inverted V-shaped guide plate 308, a pipe orifice at the lower part of the inner circulating pipe 309 is positioned below the inverted V-shaped guide plate 308, a forward pump 314 and a valve are arranged on the inner circulating pipe 309, a bypass 310 is also arranged on the inner circulating pipe 309, and a reverse pump 315 and a valve are arranged on the bypass 310; a water adding pipe 311 is further inserted into the water chamber 301, a water adding valve is arranged on the water adding pipe 311, a transverse distribution pipe 312 is arranged at the bottom of the water adding pipe 311, a plurality of water outlets 313 lower than the overflow ports 306 are arranged at the upper part of the transverse distribution pipe 312, and water is discharged upwards from the water outlets 313, so that floating objects on the liquid level are easier to discharge (the general trend of the water on the upper layer is upwards); wherein, the forward pump 314 is driven from bottom to top, the reverse pump 315 is driven from top to bottom, when the forward pump 314 works, the reverse pump 315 does not work, and the valve corresponding to the pump which does not work is also closed.

The discharge port 102 of the winnowing device 1 is communicated with the feed hopper 202 of the air screen device 2 positioned at the upper part; the discharge pipe 204 of the upper air screen device 2 is connected with the feed hopper of the lower air screen device 2 through a communicating pipe 4 with an open top, and redundant air discharged from the discharge pipe 204 can be discharged from the open top of the communicating pipe 4; the discharge pipe 204 of the air screen device 2 positioned at the lower part is communicated with the inlet pipeline 302 of the water separation device 3; the screen 205 of the upper wind sifter device 2 is inclined at an angle greater than the screen 205 of the lower wind sifter device 2, for example, the screen 205 of the upper wind sifter device 2 is inclined at an angle of 50 degrees, and the screen 205 of the lower wind sifter device is inclined at an angle of 45 degrees, because the seeds on the falling screen 205 have accumulated more potential energy when falling, and the smaller angle of the lower screen 205 is inclined to ensure that the seeds stay on the screen 205 for a sufficient time to allow the fine seeds to sift out.

The agricultural seed screening method described in this embodiment adopts the agricultural seed screening apparatus described in the above embodiment, and is characterized by sequentially including a winnowing process, two air screening processes, and a water separation process;

the winnowing process comprises the following steps: the seeds to be screened enter the winnowing device 1, lighter flat seeds, seed shells, dust and weeds are blown to the left side by the winnowing fan 103 and collected in the collection chamber 107, and other seeds to be screened fall from the lower part; most of the light shrunken seeds, seed shells and weeds can be discharged and cannot be removed by the following water separation process;

the air screening process comprises the following steps: the seeds to be screened enter the air screening device 2, the seeds to be screened fall along the screen mesh 205, the air screening fan 206 blows air towards the screen mesh 205, the seeds to be screened fall against the air, small particles in the seeds to be screened fall in the collection bin 203 at the lower left of the screen mesh 205, and normal seeds are discharged from the discharge pipe 204 of the air screening device 2;

the water separation process comprises the following steps: the seeds to be screened enter the water chamber 301, the water level in the water chamber 301 is one centimeter lower than the overflow port 306, when the seeds to be screened enter the water chamber 301, the reverse pump 315 works to disturb the water in the water chamber 301, the water is overturned upwards from the bottom, so that the seeds can be better dispersed after contacting with the water, and impurities carried in the seeds can be scattered and floated; the floating impurities contained in the seeds to be screened float on the water surface, the normal seeds sink, after all the seeds to be screened enter the water chamber 301, the seeds are precipitated for five minutes, the forward pump 314 works, meanwhile, the water adding valve is opened to enable the liquid level to be full, the forward pump 314 works, water below the inverted splayed guide plate has a suction force, the seeds which sink do not float too much when the water is added to overflow, the forward pump 314 is driven to work slower than the reverse pump to enable the water phase to be relatively stable, the floating impurities floating on the liquid level flow out from an overflow outlet to enter the overflow chamber 303, a valve on the outflow pipe 305 is opened, the floating impurities can be filtered on the blocking net 304, the forward pump 314 is stopped after the overflow lasts for five minutes, the valve on the outflow pipe 307 is opened to discharge the screened seeds, and then the water adding is stopped.

The agricultural seed screening device described in the embodiment has the advantages that: the method combining the air separation mode, the net type screening mode and the water washing mode is adopted, the screening effect is more guaranteed, the three devices are sequentially arranged from top to bottom, the three processes are sequentially completed, the working efficiency is high, the screening work of large-batch agricultural seeds is facilitated, and the practicability is high.

Example 2

Compared with embodiment 1, the structure of this embodiment is more simplified, and the details are as follows:

as shown in fig. 5, an agricultural seed screening device comprises an air separation device 1, an air screen device 2 and a water separation device 3, and is characterized in that:

the winnowing device 1 comprises a shell 101, wherein the upper part of the shell 101 is provided with a feeding hole, the bottom of the shell 101 is provided with a discharging hole 102, the right side of the shell 101 is provided with a winnowing fan 103, the left side of the shell 101 is provided with an air outlet 104 with a filter screen, a baffle 105 is eccentrically arranged near the left side in the shell 101, the left side of the baffle 105 is provided with a channel 106 extending to the outside, the channel 106 is connected with a collection chamber 107, and the collection chamber 107 is provided with an air outlet;

the air screen device 2 comprises a shell 201, a feed hopper 202 is arranged at the top of the left side of the shell 201, a collection bin 203 is arranged at the lower part of the shell 201, and an air outlet window 213 with a filter screen is arranged on the collection bin 203; a discharge pipe 204 is arranged at the lower part of the right side of the machine shell 201, an inclined screen 205 is arranged in the machine shell 201, and a discharge hopper chamber 214 connected with the collection bin 203 is arranged at the lower left part of the screen 205; an air screening fan 206 is arranged on the right side of the machine shell 201, the air screening fan 206 is connected with an air outlet pipe 209, the air outlet pipe 209 is provided with an upper air outlet and a lower air outlet which are communicated with the machine shell 201, an upper guide plate 207 and a lower guide plate 208 are arranged on the right upper side of the screen 205, the upper guide plate 207 is positioned above the upper air outlet, the lower guide plate 208 is positioned above the lower air outlet, the left ends of the upper guide plate 207 and the lower guide plate 208 are both upturned, the distance between the upturned part 210 and the screen 205 is larger when the upturned part is more upward, and an exhaust pipe 211 is arranged at the top of;

the water separation device 3 comprises a water chamber 301, an inlet pipeline 302 is arranged on the left side of the top of the water chamber 301, an overflow chamber 303 is arranged on the upper right part of the outer side of the water chamber 301, a blocking net 304 is arranged in the middle of the overflow chamber 303, an outlet pipe 305 is arranged on the lower part of the overflow chamber 303, and a valve is arranged on the outlet pipe 305; the water chamber 301 is communicated with the overflow chamber 303 through an overflow port 306; the bottom of the water chamber 301 is an inclined plane with a higher left part and a lower right part, an outlet pipeline 307 is arranged at the right bottom of the water chamber 301, and a valve is arranged on the outlet pipeline 307; an inverted V-shaped guide plate 308 is arranged at the lower part in the water chamber 301, an internal circulation pipe 309 is arranged at the left lower part of the water chamber 301, a pipe orifice at the upper part of the internal circulation pipe 309 is positioned above the inverted V-shaped guide plate 308, a pipe orifice at the lower part of the internal circulation pipe 309 is positioned below the inverted V-shaped guide plate 308, a forward pump 314 and a valve are arranged on the internal circulation pipe 309, a bypass 310 is also arranged on the internal circulation pipe 309, and a reverse pump 315 and a valve are arranged on the bypass 310; a water adding pipe 311 is also inserted into the water chamber 301, a water adding valve is arranged on the water adding pipe 311, a transverse distribution pipe 312 is arranged at the bottom of the water adding pipe 311, and a plurality of water outlets 313 lower than the overflow ports 306 are arranged at the upper part of the transverse distribution pipe 312;

the discharge port 102 of the winnowing device 1 is communicated with the feed hopper 202 of the air screening device 2; the discharge pipe 204 of the air screening device 2 is communicated with the inlet pipeline 302 of the water separation device 3.

The agricultural seed screening method described in this embodiment adopts the agricultural seed screening apparatus described in this embodiment 2, and is characterized by sequentially including a winnowing process, an air screening process, and a water screening process;

the winnowing process comprises the following steps: seeds to be screened enter the winnowing device 1, lighter flat seeds, seed shells, dust and weeds are blown to the left side by the winnowing fan 103 and collected in the collection chamber 107, and other seeds to be screened fall into the winnowing device from the lower part;

the air screening process comprises the following steps: the seeds to be screened enter the air screening device 2, the seeds to be screened fall along the screen mesh 205, the air screening fan 206 blows air towards the screen mesh 205, the seeds to be screened fall against the air, small particles in the seeds to be screened fall in the collecting bin 203 at the lower left of the screen mesh 205, and normal seeds are discharged from the discharge pipe 204 of the air screening device 2 and fall into the water separation device;

the water separation process comprises the following steps: when seeds to be screened enter the water chamber 301, the water level in the water chamber 301 is lower than the overflow port 306 by one centimeter, when the seeds to be screened enter the water chamber 301, the reverse pump 315 works to disturb the water in the water chamber 301, so that floatable impurities contained in the seeds to be screened float on the water surface, normal seeds sink, after all the seeds to be screened enter the water chamber 301 and settle for five minutes, the forward pump 314 works, the water adding valve is opened to make the liquid level full, the floatable impurities floating on the liquid level flow out from the overflow port into the overflow chamber 303, the valve on the outflow pipe 305 is opened, the floatable impurities are filtered on the blocking net 304, the forward pump 314 is stopped after the overflow lasts for five minutes, the valve on the outlet pipeline 307 is opened to discharge the screened seeds, and then the water adding is stopped.

Although the agricultural seed screening device described in the embodiment has a simpler structure, the screening effect is still guaranteed by adopting a method of combining three screening modes of air separation, net type screening and water washing, the screening effect is better than that of the prior art, three devices are sequentially arranged from top to bottom, three processes are sequentially completed, the working efficiency is high, the screening work of large-batch agricultural seeds is facilitated, and the practicability is high.

The agricultural seed screening device and method disclosed by embodiments 1 and 2 of the invention can be used for screening rice and wheat.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still make modifications to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some technical features, and therefore, all should fall within the scope of the present invention.

Claims

1. The utility model provides an agricultural seed sieving mechanism, includes a wind selector (1), two wind sieve devices (2) and a water selection device (3), two wind sieve devices (2) one is located upper portion, another is located the lower part, its characterized in that:

the air separation device (1) comprises a shell (101), wherein a feed inlet is formed in the upper part of the shell (101), a discharge outlet (102) is formed in the bottom of the shell (101), an air separation fan (103) is arranged on the right side of the shell (101), an air outlet (104) with a filter screen is formed in the left side of the shell (101), a baffle (105) is eccentrically arranged in the shell (101) close to the left, a channel (106) extending to the outside is formed in the left side of the baffle (105), the channel (106) is connected with a collection chamber (107), and an air outlet window with the filter screen is formed;

the air screen device (2) comprises a machine shell (201), a feed hopper (202) is arranged at the top of the left side of the machine shell (201), a collection bin (203) is arranged at the lower part of the machine shell (201), and an air outlet window (213) with a filter screen is arranged on the collection bin (203); a discharge pipe (204) is arranged at the lower part of the right side of the machine shell (201), an inclined screen (205) is arranged in the machine shell (201), and a discharge hopper chamber (214) connected with the collection bin (203) is arranged at the lower left part of the screen (205); an air screen fan (206) is arranged on the right side of the machine shell (201), the air screen fan (206) is connected with an air outlet pipe (209), the air outlet pipe (209) is provided with an upper air outlet and a lower air outlet which are communicated with the machine shell (201), an upper guide plate (207) and a lower guide plate (208) are arranged on the right upper side of the screen mesh (205), the upper guide plate (207) is positioned above the upper air outlet, the lower guide plate (208) is positioned above the lower air outlet, the left ends of the upper guide plate (207) and the lower guide plate (208) are both upturned, the distance between the upturned part (210) and the screen mesh (205) is larger when the upturned part is upward, and an exhaust pipe (211) is arranged at the top of the;

the water separation device (3) comprises a water chamber (301), an inlet pipeline (302) is arranged on the left side of the top of the water chamber (301), an overflow chamber (303) is arranged on the right upper part of the outer side of the water chamber (301), a blocking net (304) is arranged in the middle of the overflow chamber (303), an outlet pipe (305) is arranged on the lower part of the overflow chamber (303), and a valve is arranged on the outlet pipe (305); the water chamber (301) is communicated with the overflow chamber (303) through an overflow port (306); the bottom of the water chamber (301) is an inclined plane with a higher left part and a lower right part, an outlet pipeline (307) is arranged at the right bottom of the water chamber (301), and a valve is arranged on the outlet pipeline (307); an inverted V-shaped guide plate (308) is arranged at the lower part in the water chamber (301), an inner circulating pipe (309) is arranged at the left lower part of the water chamber (301), a pipe orifice at the upper part of the inner circulating pipe (309) is positioned above the inverted V-shaped guide plate (308), a pipe orifice at the lower part of the inner circulating pipe (309) is positioned below the inverted V-shaped guide plate (308), a forward pump (314) and a valve are arranged on the inner circulating pipe (309), a bypass (310) is also arranged on the inner circulating pipe (309), and a reverse pump (315) and a valve are arranged on the bypass (310); a water adding pipe (311) is also inserted into the water chamber (301), a water adding valve is arranged on the water adding pipe (311), a transverse distribution pipe (312) is arranged at the bottom of the water adding pipe (311), and a plurality of water outlets (313) lower than the overflow ports (306) are arranged at the upper part of the transverse distribution pipe (312);

the discharge hole (102) of the air separation device (1) is communicated with a feed hopper (202) of the air screen device (2) positioned at the upper part; a discharge pipe (204) of the air screen device (2) positioned at the upper part is connected with a feed hopper of the air screen device (2) positioned at the lower part through a communicating pipe (4) with an open top; a discharge pipe (204) of the air screen device (2) positioned at the lower part is communicated with an inlet pipeline (302) of the water separation device (3); the inclination angle of the screen (205) of the upper air screen device (2) is larger than that of the screen (205) of the lower air screen device (2).

2. An agricultural seed screening method, which adopts the agricultural seed screening device of claim 1, is characterized by comprising a wind separation process, a two-pass wind screen process and a water separation process in sequence;

the winnowing process comprises the following steps: the seeds to be screened enter the winnowing device (1), lighter flat seeds, seed shells, dust and weeds are blown to the left side by the winnowing fan (103) and collected in the collection chamber (107), and other seeds to be screened fall from the lower part;

the air screening process comprises the following steps: the seeds to be screened enter the air screening device (2), the seeds to be screened fall along the screen mesh (205), an air screening fan (206) blows air to the direction of the screen mesh (205), so that the seeds to be screened fall against the air, small particles in the seeds to be screened fall into a collection bin (203) at the lower left of the screen mesh (205), and normal seeds are discharged from a discharge pipe (204) of the air screening device (2);

the water separation process comprises the following steps: when seeds to be screened enter the water chamber (301), the water level in the water chamber (301) is lower than the overflow port (306) by one centimeter, when the seeds to be screened enter the water chamber (301), the reverse pump (315) works to disturb the water in the water chamber (301), so that floatable impurities contained in the seeds to be screened float on the water level, normal seeds sink, all the seeds to be screened enter the water chamber (301) and settle for five minutes, the forward pump (314) works, meanwhile, the water adding valve is opened to enable the liquid level to be full, the floatable impurities floating on the liquid level flow out from the overflow port to enter the overflow chamber (303), the valve on the outflow pipe (305) is opened, the floatable impurities are filtered on the blocking net (304), the forward pump (314) is stopped after the overflow lasts for five minutes, the valve on the outlet pipe (307) is opened to discharge the screened seeds, and then the water adding is stopped.