CN216409573U

CN216409573U - Multi-section grain drying device

Info

Publication number: CN216409573U
Application number: CN202123262264.9U
Authority: CN
Inventors: 刘英海; 史德才; 史乾军
Original assignee: Quanjiao Jinzhu Mechanical Manufacturing Co ltd
Current assignee: Quanjiao Jinzhu Mechanical Manufacturing Co ltd
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2022-04-29
Anticipated expiration: 2031-12-23

Abstract

The utility model discloses a multi-section grain drying device, which relates to the technical field of drying devices and comprises a drying tower, wherein a top feeding buffer box and a grain scattering equipartition device are fixedly installed at the top of the drying tower, a top flow pipe is fixedly connected to the top of the top feeding buffer box, the drying tower comprises a plurality of tower layers which are arranged from bottom to top, a preheating layer, a first ventilation layer, a first drying layer, a first tempering layer, a second ventilation layer, a second drying layer and a second tempering layer are sequentially arranged in the drying tower from top to bottom, the drying tower further comprises a bucket elevator, a feeding opening is fixedly installed at the feeding end of the bucket elevator, a three-way distributor is fixedly installed at the discharging end of the bucket elevator, and the three-way distributor is communicated with the top flow pipe. The multi-section grain drying device provided by the utility model dries grains according to the sequence of preheating, ventilating, drying, tempering, ventilating, drying and tempering, and reduces the waist bursting rate of the grains.

Description

Multi-section grain drying device

Technical Field

The utility model relates to the technical field of drying devices, in particular to a multi-section grain drying device.

Background

The production area drying is an essential important link in the grain production process, but the grain drying proportion in China only accounts for 10-15%, the mechanization level of grain drying devices in developed countries in Europe and America reaches over 90%, the mechanization level of grain drying devices in Japan reaches 92%, and the mechanization of grain drying devices is still a short board for the whole-process automation of agricultural machinery in China.

The utility model discloses a grant publication number CN203869457U, grant publication date as 2014 10 months 08 days, the utility model patent of title "a cereal circulation desiccator", it includes from lower supreme radiation drying section, arrange grain section, hot air drying section and the grain storage section of establishing on the base in proper order, is equipped with material circulation conveyer between radiation drying section discharge gate and grain storage section feed inlet, and the heat source that can produce hot-medium is connected to radiation drying section one side, is equipped with draught fan and plenum respectively in hot air drying section both sides, plenum inlet and the hot-medium export of radiation drying section intercommunication, plenum outlet pass through the hot air drying section with the draught fan intercommunication, solved the hot-air that far infrared drying device produced through the fuel burner mixes with cold air in the cold and hot air mixing chamber, rethread hot air inlet gets into infrared drying section after, can not fine loop through otter board, The grain layer enters the air exhaust mesh cylinder to be exhausted, most of the grain layer can rise along the gap between the screen plate and the shell of the hot air drying section, so that the grain cannot be dried by hot air better in the hot air drying section, the residual heat energy exhausted by the cylinder type far infrared radiator cannot be fully utilized, and the problem of certain heat energy waste exists.

Multistage formula grain drying device among the prior art can make inside moisture of cereal discharge cereal fast in the drying in vitro, the waist-bursting rate of cereal is higher.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a multi-section grain drying device to solve the defects in the prior art.

In order to achieve the above purpose, the utility model provides the following technical scheme:

multistage formula grain drying device, including a drying tower, the top fixed mounting of drying tower has a roof feeding baffle-box and spills the grain and equally divide the ware, a roof flow pipe of top fixedly connected with of roof feeding baffle-box, the drying tower includes the tower layer that a plurality of layers from the bottom up were arranged, the inside top-down of drying tower has set gradually preheating layer, first ventilation layer, first stoving layer, first slow suzhou layer, second ventilation layer, second stoving layer, second slow suzhou layer, still includes a bucket elevator, the feed end fixed mounting of bucket elevator has a feed inlet, the discharge end fixed mounting of bucket elevator has a tee bend tripper, tee bend tripper is linked together with roof flow pipe.

Furthermore, a centralized air inlet box and a centralized air exhaust box are arranged on the periphery of the drying tower.

Furthermore, the device also comprises two centrifugal fans, wherein a hot air control valve is installed on each centrifugal fan, a hot air pipeline is installed at one end of each centrifugal fan, and a gas conversion box is installed at the other end of each centrifugal fan.

Furthermore, the week side of drying tower is provided with a plurality of gas vent, exhaust duct is installed to the position of gas vent.

Furthermore, a discharge flow pipe is fixedly arranged at the outlet end of the three-way distributor.

Furthermore, a grain discharging mechanism layer is further arranged inside the drying tower, and a grain discharging hopper is arranged at the position of the grain discharging mechanism layer.

Furthermore, the bottom of the top feeding buffer box is fixedly connected with a top material flowing nozzle, one side of the top material flowing nozzle is provided with an upper trapezoidal groove, the other side of the top material flowing nozzle is provided with a lower trapezoidal groove, and two sides of the inner wall of the upper trapezoidal groove are fixedly connected with a material guide plate.

In the technical scheme, the multi-section grain drying device provided by the utility model dries grains according to the sequence of preheating, ventilating, drying, tempering, ventilating, drying and tempering by arranging the preheating layer, the first ventilating layer, the first drying layer, the first tempering layer, the second ventilating layer, the second drying layer and the second tempering layer, namely, the combination of multiple effective air flow running directions is added in one drying cycle, so that moisture in the grains is slowly discharged out of the grains, and the loin bursting rate of the grains is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings can be obtained by those skilled in the art according to the drawings.

Fig. 1 is a schematic overall structure view of a multi-stage grain drying device according to an embodiment of the present invention;

fig. 2 is a schematic overall structure view of a multi-stage grain drying device according to an embodiment of the present invention;

fig. 3 is a schematic overall structure view of a multi-stage grain drying device according to an embodiment of the present invention;

FIG. 4 is a flow chart illustrating the operation of the multi-stage grain drying apparatus according to the embodiment of the present invention;

FIG. 5 is a schematic view of the connection between the top feeding buffer box and the top material dripping nozzle of the multi-stage grain drying device according to the embodiment of the present invention;

fig. 6 is a schematic structural view of a top material flowing nozzle of the multi-stage grain drying device according to the embodiment of the present invention.

Description of reference numerals:

1. a feeding port; 2. a bucket elevator; 3. a three-way material distributor; 4. a set top flow tube; 5. a set-top feed buffer bin; 6. a grain scattering equipartition device; 7. a preheating layer; 8. a first ventilation layer; 9. a first drying layer; 10. a first tempering layer; 11. a second ventilation layer; 12. a second drying layer; 13. a second tempering layer; 14. a centralized air inlet box; 15. a centralized exhaust box; 16. a grain discharging mechanism layer; 17. a grain discharging hopper; 18. a hot air control valve; 19. a gas transfer box; 20. a centrifugal fan; 21. a hot air duct; 22. an exhaust port; 23. an exhaust duct; 24. a discharge flow tube; 25. a material flowing nozzle is arranged on the machine top; 26. a material guide plate.

Detailed Description

In order to make the technical solutions of the present invention better understood, those skilled in the art will now describe the present invention in further detail with reference to the accompanying drawings.

Referring to fig. 1-6, the multi-stage grain drying device provided by the utility model comprises a drying tower, wherein a top feeding buffer box 5 and a grain scattering equipartition device 6 are fixedly installed at the top of the drying tower, a top flow pipe 4 is fixedly connected to the top of the top feeding buffer box 5, the drying tower comprises a plurality of tower layers arranged from bottom to top, a preheating layer 7, a first ventilation layer 8, a first drying layer 9, a first tempering layer 10, a second ventilation layer 11, a second drying layer 12 and a second tempering layer 13 are sequentially arranged in the drying tower from top to bottom, the drying tower further comprises a bucket elevator 2, a feeding port 1 is fixedly installed at the feeding end of the bucket elevator 2, a three-way material distributor 3 is fixedly installed at the discharging end of the bucket elevator 2, and the three-way material distributor 3 is communicated with the top flow pipe 4.

Specifically, the multi-stage grain drying device provided by this embodiment is used for drying grains.

The main point of this embodiment is that as shown in fig. 6, the grain spreading distributor 6 comprises a grain spreading tray, and grains fall on the grain spreading tray through the top feeding buffer box 5.

According to the multi-section grain drying device provided by the embodiment of the utility model, the preheating layer, the first ventilation layer, the first drying layer, the first tempering layer, the second ventilation layer, the second drying layer and the second tempering layer are arranged, grains are dried according to the sequence of preheating, ventilation, drying, tempering, ventilation, drying and tempering, namely, the combination of multiple effective air flow running directions is added in one drying cycle, so that moisture in the grains is slowly discharged out of the grains, and the waist burst rate of the grains is reduced.

In another embodiment of the present invention, further, the drying tower is provided with a centralized air intake box 14 and a centralized air exhaust box 15 on the periphery, and further includes two centrifugal fans 20, the centrifugal fans 20 are provided with hot air control valves 18, one end of the centrifugal fan 20 is provided with a hot air pipeline 21, the other end of the centrifugal fan 20 is provided with an air conversion box 19, the periphery of the drying tower is provided with a plurality of air exhaust ports 22, the positions of the air exhaust ports 22 are provided with air exhaust pipelines 23, the outlet end of the three-way distributor 3 is fixedly provided with a discharge flow pipe 24, the drying tower is further provided with a grain discharging mechanism layer 16 inside, and the position of the grain discharging mechanism layer 16 is provided with a grain discharging hopper 17.

In still another embodiment of the present invention, further, a top material flowing nozzle 25 is fixedly connected to the bottom of the top feeding buffer box 5, an upper trapezoidal groove is formed on one side of the top material flowing nozzle 25, a lower trapezoidal groove is formed on the other side of the top material flowing nozzle 25, a material guiding plate 26 is fixedly connected to both sides of the inner wall of the upper trapezoidal groove, an upper trapezoidal groove and a lower trapezoidal groove are formed on the top material flowing nozzle 25, and two material guiding plates 26 are installed on both sides of the inner wall of the upper trapezoidal groove, so that grains in the top material flowing nozzle 25 fall down from the middle area and grains on both sides respectively, grains falling onto the material scattering plate are in a triangular falling point, grains are scattered more uniformly by three-point blanking, the effective volume in the bin is increased, and the utilization rate in the bin is increased.

The mechanical structure of the research product is compact in design, the occupied area of the basic part of the grain drying device is small, the net width in a tower bin of the grain drying device is 2200mm, and the net length in the tower bin of the grain drying device is 3500 mm. The basic part of the grain drying device is 4 layers, wherein 1-3 layers are provided with a grain discharging hopper layer, the flowing angle of the grain discharging hopper is 45 degrees, the lower part of the grain discharging hopper is provided with a butt-joint rectangular flow pipe, and grains flow to a feeding nozzle of a hoister through the gravity of an inclination angle. The upper part of the grain discharging hopper is butted with the grain discharging mechanism layer on the 4 th layer and is used for receiving grains discharged from the grain discharging layer at a constant speed. The grain discharging mechanism is divided into 8 grain discharging and dripping troughs, 8 groups of grain discharging wheels are matched, 2 sets of variable-frequency speed reducing motors are adopted to drive through chains, so that grain layers uniformly descend, the descending speed of the dried grain layers can be controlled in a variable frequency mode, and the precipitation rate is adjusted.

The grain discharging mechanism layer is the 4 th layer of the grain drying device. From bottom to top, the 5 th layer is a tempering layer, the 6 th to 8 th layers are a first group of drying layers, and each layer is provided with 12 air inlet grooves and 11 air outlet grooves.

The 9 th layer is a ventilation layer and is provided with 11 exhaust air ducts. The 10 th layer is a tempering layer, the 11 th to 13 th layers are a second group of drying layers, and each layer is provided with 12 air inlet grooves and 11 air outlet grooves. The 14 th layer is a ventilation groove and is provided with 11 exhaust air grooves. The 15 th layer to the 19 th layer is a grain storage preheating layer (slow tempering).

The drying layer and the ventilation layer are arranged, an inlet of the air inlet groove is formed in the pulling plate in the centralized air inlet box, and no hole is formed in the pulling plate in the centralized exhaust box. The air outlet of the exhaust air duct is arranged on the pull plate in the centralized exhaust box, and no hole is arranged on the pull plate in the centralized air inlet box. The drying layer and the ventilation layer of the grain drying device are provided with 72 air inlet grooves and 88 air outlet grooves, and the air inlet grooves and the air outlet grooves are arranged on the drying layer and the ventilation layer in a crossed and staggered mode.

The grain drying device comprises a main tower from the 5 th layer to the 14 th layer, a box body with the rear part of 300mm is a centralized air inlet box, and a box body with the front part of 300mm is a centralized air exhaust box. 2 centrifugal fan pass through hot-blast pipeline with hot-blast, malleation respectively is carried to grain drying device and is concentrated inlet box, and the import is located 6 th floor and 11 th floor respectively. The air outlet is positioned on the 7 th, 9 th, 11 th and 13 th layers of the centralized exhaust box, and 4 sets of exhaust pipelines are arranged in total.

The bucket elevator is positioned right in front of the drying surface, a feeding port at the lower part of the elevator is respectively butted with a grain discharging hopper and a feeding port, the feeding port is used for feeding wet grains for the first time, and the grain discharging hopper and a lower interface of the bucket elevator are channels for grain flowing in the circulating drying process. An electric material distributing tee joint is arranged on the lower portion of a discharge port of the top of the bucket elevator, the tee joint distributes materials to a flow pipe of the top of the elevator, grains enter a feeding buffer box of the top of the elevator through the flow pipe, a material dripping nozzle is arranged below the buffer box, and the grains enter a grain scattering and equally distributing device. The grain spreading equipartition device is arranged at the center of the lower part of the top cover plate of the grain drying device, and the radius of the grain spreading is 1100 mm. Through the control of the three-way material distributor, dried grains can be discharged from the material discharge flow pipe through the three-way valve.

The grain drying device comprises a feeding nozzle, a bucket elevator, a material distributing tee joint, a machine top flow pipe, a machine top feeding buffer box, a grain scattering equipartition device, a grain drying device main tower bin, a grain discharging mechanism layer and a grain discharging hopper, and a material conveying flow path for circular drying is formed.

The part below 4 layers of the grain drying device foundation adopts a national standard section bar welding inner supporting frame and is connected with a pull rod which is engaged longitudinally and transversely. In the upper box body of the grain drying device, a combined pull rod, a longitudinal pull rod and a transverse pull rod are respectively combined and cross-meshed to be installed, so that the whole structure of the grain drying device is stable.

The mechanical working principle flow of the grain drying device is as follows: (see FIG. 4)

Wet grain-feeding mouth-bucket elevator-three-way distributor-machine top flow tube-machine top feeding buffer box-grain-spreading distributor-preheating layer (grain storage layer) -first ventilating layer-first drying layer-first tempering layer-second ventilating layer-second drying layer-second tempering layer-grain discharging hopper-feeding mouth (circulation drying), (after grain drying reaches set water content) grain discharging layer-grain discharging hopper-feeding mouth-bucket elevator-three-way distributor-discharging flow tube-dry grain discharging material, hot-blast stove-heat supply air pipe-hot air control valve x 2-gas conversion box x 2-centrifugal fan x 2-hot air pipeline x 2-centralized air inlet box-dispersed air inlet air channel-dispersed air outlet air channel-centralized air outlet box-exhaust outlet-dust reducing chamber.

And (3) explaining a grain operation flow: the wet grain cleaned by the cleaning equipment is sent to a feeding port of the elevator through a discharging flow pipe of other conveying equipment. The feeding port is four-way, the lower oblique port is butted with the base of the hoister, and the materials enter the lower part of the hoister from the lower oblique port. The upper front part is a wet grain first feeding port from which wet grains are fed until the dryer is full. The feeding port is arranged at the rear part of the upper part of the machine body and is used for butting a rectangular inclined pipe at the lower part of a grain discharging hopper, and the rectangular inclined pipe is a channel for discharging grains in the grain discharging hopper to a lifting machine base in the circulating drying process. The middle position of the upper part is the position of a front dust suction port and is used for installing a square connecting circle of the dust suction port; when the dryer is filled, wet grains enter a base of the hoister through a feeding port of the hoister, a bucket type hoister lifts the wet grains to a machine head, and the wet grains are controlled to flow to a top flow pipe of the dryer through a three-way distributor and a control three-way distributor; the wet grain flows to a feeding buffer box arranged on the top of the machine through the gravity of a flow pipe on the top of the machine, and flows to an inclined material flowing nozzle at the lower part of the buffer box after being buffered by the buffer box, and the material in the material flowing nozzle obliquely flows into the center of a grain scattering plate of a grain scattering equipartition device; the grain scattering and evenly dividing plate rotates to enable wet grains to be in an annular parabolic shape, and the wet grains are scattered evenly and fall into a tower bin of the dryer; in the filling process of the dryer, the dust removal air net is opened, after the wet grains are full of the bin, the feeding is stopped after the full amount alarm, and the circular drying operation is started; after the centrifugal fan, the dust removal air net, the bucket elevator and the grain scattering equipartition device are all started, 8 groups of grain discharging wheels of the grain discharging mechanism layer start to discharge at a constant speed, grains enter the elevator through a grain discharging hopper after being discharged, and enter the dryer for grain scattering and equipartition after being lifted again; wet grains enter a grain storage tempering layer on the uppermost part of the dryer, the moisture of the wet grains is uniformly mixed in the grain storage tempering layer, and the wet grains are tempered for a long time; the wet valley descends and enters a ventilation layer, hot air penetrates through the grain layer across the layer after being dispersed from the air inlet tank, and enters the air exhaust tank to exhaust waste gas to the centralized exhaust box; grains enter the first group of three drying layers, hot air enters the air inlet grooves in the centralized air inlet box, penetrates the grain layers among the air grooves, is dispersedly discharged to the air exhaust grooves arranged on the drying layers, and is discharged to the centralized air exhaust box by utilizing the hot air. The left outer plate and the right outer plate are provided with side ventilation grooves, hot air penetrates through grains at the edges through the side ventilation grooves, and the utilized waste gas is discharged to a centralized exhaust box through exhaust outlets of the side ventilation grooves; the grains descend into a tempering layer for tempering; then the hot air enters the ventilation layer in the afternoon, after the hot air is dispersed from the air inlet tank, the hot air penetrates through the grain layer in a cross-layer manner, enters the air exhaust tank and is exhausted to the centralized exhaust box; grains enter the second group of three drying layers, hot air enters the air inlet grooves in the centralized air inlet box, penetrates through grain layers among the air grooves, is dispersedly discharged to the air exhaust grooves arranged on the drying layers, and is discharged to the centralized air exhaust box by utilizing the hot air. The left outer plate and the right outer plate are provided with side ventilation grooves, hot air penetrates through grains at the edges through the side ventilation grooves, and the utilized waste gas is discharged to a centralized exhaust box through exhaust outlets of the side ventilation grooves; the grains descend into a tempering layer for tempering; the grain discharging mechanism is equally divided into 8 grids, 2 variable-frequency speed reducing motors drive 4 grain discharging wheels respectively on the left and right sides through chain transmission, so that grains on the upper parts of 4 layers in the dryer bin descend at a constant speed, and the grain layers are kept to descend synchronously; during the drying process of the lower parts of the centralized air inlet box and the centralized air exhaust box, a small amount of grains, chaffs, small sundries and dust seeped out from the air inlet notch and the air exhaust notch all fall into a grain discharge hopper at the lower part through a 30-degree inclined dropping plate at the lower part of the box body; in the process that the grains are discharged by the grain discharging wheel of the grain discharging mechanism, 3 dust removing suction ports are arranged at the lower part of the material dripping plate of the grain discharging mechanism layer, and dust, chaff and small impurities raised by the grains discharged by the grain discharging wheel are sucked out; after the grains fall into a grain discharge hopper, the grains descend to the rectangular pipeline through the gravity of the 45-degree inclined hopper and then fall into a feeding port of the hoister, dust, chaff and small impurities from a grain yard are sucked by a dust removal suction port of the feeding port while the grains fall into the feeding port, and dust is discharged to a dust reduction chamber after being intensively led to a dust removal fan at the lower part; after the grains are lifted by the bucket elevator again, the grains enter the grain storage tempering layer at the upper part of the grain dryer again through the three-way material distributor, the top flow pipe, the buffer bin and the grain scattering equipartition device again, and the next circulating drying operation is carried out again; after the grains are circularly dried to reach the set moisture value, the on-line moisture monitor monitors the moisture value, the on-line moisture monitor automatically shuts down the circular drying, the centrifugal fan and the hot blast stove are shut down, the bucket elevator lifts the grains to the top of the machine, dried grains are discharged to a discharge flow pipe by controlling the three-way material distributor, and the dried grains are discharged for loading or are transferred into other conveying equipment for transferring; the heat supply equipment provides hot air, the hot air is dispersedly conveyed to the 2 hot air control valves through a hot air main pipeline, and the hot air quantity respectively entering the 2 gas conversion boxes is controlled through the adjustment of the hot air control valves; normal air is supplemented into the gas conversion box through a manual air supplementing louver opening and 2 small electric temperature control air supplementing louver openings which are arranged on the gas conversion box, and the normal air is used for adjusting the air temperature of hot air in the gas conversion box; the centrifugal fans respectively suck hot air which is supplemented and adjusted in temperature in the matched gas conversion box, the hot air is pressed into the centralized air inlet box through the hot air pipeline in positive pressure, the hot air provided by the 2 fans in positive pressure respectively enters the 6 th layer and the 11 th layer, and the hot air is primarily dispersed; hot air enters the centralized air inlet box, the hot air dispersedly enters air inlets of 72 air inlet air grooves which are arranged in 6 rows of 6 drying layers, the air inlet air grooves are of a ridge-shaped bottomless structure, the hot air is dispersedly discharged from the bottoms of the air inlet air grooves, penetrates through grain layers in gaps between the air inlet air grooves and the air outlet air grooves, and the grains are dried; hot air penetrating through the grain layer enters the bottoms of 88 exhaust air grooves which are arranged on 6 drying layers and 2 ventilation layers and 8 rows, the utilized waste gas passes through the dispersed exhaust air grooves and is dispersedly exhausted to the concentrated exhaust box through the air groove openings formed in the concentrated exhaust box, meanwhile, the waste gas penetrating through the grain layer to the left side and the right side is exhausted through 16 outer ventilation grooves which are arranged on 8 layers and is exhausted to the concentrated exhaust box through 16 air outlets; the waste gas in the centralized exhaust box passes through 4 exhaust ports, is respectively positioned on 7, 9, 11 and 13 layers, passes through 4 inclined-port exhaust boxes, and is exhausted to a dust settling chamber through an exhaust pipeline after being dried and utilized; a special dust removal box and a dust removal fan are arranged at the top of the machine, dust raised in the grain scattering and evenly distributing disc rotating grain throwing process is absorbed and discharged to a dust falling chamber; when cereal reaches and sets for the moisture content, the hot blast air supply device stops the heat supply, opens gas transfer box and mends the wind tripe mouth, supplements a large amount of normality air, and each multilayer multitube dispersion wind groove is impressed in through centrifugal fan dispersion to the normality air, carries out cooling cycle to the cereal after drying to reduce the difference of discharge cereal and normal atmospheric temperature, in order to reduce the emergence of the cereal condition of regaining of moisture after drying.

While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that the described embodiments may be modified in various different ways without departing from the spirit and scope of the utility model. Accordingly, the drawings and description are illustrative in nature and should not be construed as limiting the scope of the utility model.

Claims

1. The multi-section grain drying device is characterized by comprising a drying tower, wherein the top of the drying tower is fixedly provided with a top feeding buffer box (5) and a grain scattering equipartition device (6), the top of the top feeding buffer box (5) is fixedly connected with a top flow pipe (4), and the drying tower comprises a plurality of tower layers arranged from bottom to top;

a preheating layer (7), a first ventilation layer (8), a first drying layer (9), a first tempering layer (10), a second ventilation layer (11), a second drying layer (12) and a second tempering layer (13) are sequentially arranged in the drying tower from top to bottom;

still include a bucket elevator (2), the feed end fixed mounting of bucket elevator (2) has a feeding mouth (1), the discharge end fixed mounting of bucket elevator (2) has a tee bend tripper (3), tee bend tripper (3) are linked together with roof flow tube (4).

2. The multi-stage grain drying device according to claim 1, wherein the drying tower is provided with a centralized air intake box (14) and a centralized air exhaust box (15) on the periphery.

3. The multi-stage grain drying device according to claim 1, further comprising two centrifugal fans (20), wherein the centrifugal fans (20) are provided with hot air control valves (18), one end of each centrifugal fan (20) is provided with a hot air pipe (21), and the other end of each centrifugal fan (20) is provided with a gas conversion box (19).

4. The multi-stage grain drying device according to claim 1, wherein a plurality of exhaust ports (22) are disposed around the drying tower, and an exhaust duct (23) is installed at the position of the exhaust ports (22).

5. The multi-stage grain drying unit according to claim 1, wherein the outlet end of the three-way distributor (3) is fixedly provided with a discharge flow pipe (24).

6. The multi-stage grain drying device according to claim 1, wherein a grain discharging mechanism layer (16) is further disposed inside the drying tower, and a grain discharging hopper (17) is installed at a position of the grain discharging mechanism layer (16).

7. The multi-stage grain drying device according to claim 1, wherein a top material dripping nozzle (25) is fixedly connected to the bottom of the top feeding buffer box (5), an upper trapezoidal groove is formed in one side of the top material dripping nozzle (25), a lower trapezoidal groove is formed in the other side of the top material dripping nozzle (25), and a material guiding plate (26) is fixedly connected to both sides of the inner wall of the upper trapezoidal groove.