Grain dryer

Abstract

The invention relates to a grain dryer which comprises a grain inlet layer, a drying layer, a grain outlet layer, a conveyor and an elevator, the grain inlet layer, the drying layer, the grain outlet layer and the conveyor are sequentially communicated from top to bottom, the conveyor is communicated with the lower end of the elevator, the upper end of the elevator is communicated with the grain inlet layer, and the drying layer comprises a drying shell and an air return fan. A drying cavity, an air inlet cavity, an air outlet cavity and an air return cavity are formed in the drying shell, a plurality of net pipe type air pipes are vertically arranged in the drying cavity at intervals, grains circularly enter the net pipe type air pipes of the drying cavity from top to bottom to be dried under the lifting of a lifting machine, hot air enters the drying cavity from the air inlet cavity and is blown into the drying cavity through an air return fan, and the drying effect is improved. Communicated air outlets are formed between the drying cavity and the air inlet cavity and between the drying cavity and the air outlet cavity, so that part of hot air is blown out of the air outlet cavity, and the other part of hot air is attracted by the air return fan to form hot air backflow. The improved grain dryer is provided with the drying layer, so that the drying layer has the effects of hot air backflow and reduction of impact on grains.

Description

Technical Field

[0001] The present invention relates to the field of grain drying equipment, and particularly to a grain dryer. Background Art

[0002] A grain dryer is an agricultural mechanical equipment used to reduce the moisture content of grains (such as rice, wheat, corn, etc.). Its main function is to quickly remove the excess moisture in the grains by controlling the temperature and air flow, prevent mildew, germination or pests, thereby extending the storage time and maintaining the grain quality. Currently, grain dryers generally adopt a horizontal angular box array drying layer structure. The grains are lifted above the drying layer by a lifting device, so that the grains can flow through the drying layer from top to bottom to achieve the drying of the grains. The grains falling from the drying layer are conveyed to the lifting device through a conveying device, so that the grains can circulate through the drying layer. The existing horizontal angular box array drying layer structure has limitations in structural design and defects in the structure of unitized modules. Due to the limitations in structural design, the hot air circulation efficiency is insufficient. The horizontal angular boxes are arranged in a horizontal matrix in the drying layer, and a grain flow channel is formed between adjacent angular boxes. The hot air penetrates the grain layer unidirectionally through the ventilation holes / gaps on the surface of the angular boxes. Although the basic drying function can be achieved, limited by the horizontal layout, a hot air reflux path cannot be formed in the drying layer, resulting in low waste heat utilization rate, increased energy consumption, and mechanical impact causing deterioration of grain quality. The falling grain flow directly collides with the surface of the horizontal angular box. Especially under high-speed drying conditions, the mechanical impact force is likely to cause damage to the epidermis or internal cracks of grain particles (such as rice, corn), significantly increasing the cracking rate and directly affecting the commercial value and storage stability. Due to the contradiction between load-bearing and durability in the structure of unitized modules, the horizontal angular boxes are arranged in a modular matrix. A single unit integrates multiple groups of angular boxes and constitutes the drying layer through splicing. During continuous operation, the unit structure needs to bear the vertical load and hot air pressure of tons of grains, and is prone to local deformation or even fracture due to stress concentration, requiring strict requirements for material strength and welding technology, resulting in a significant increase in the manufacturing cost of the equipment. Moreover, the structure of unitized modules also leads to high maintenance costs. The modular design results in poor fault tolerance for maintenance: a single angular box failure requires the disassembly of the entire matrix unit, and the maintenance operation involves large-scale shutdown and structural reorganization, seriously affecting production continuity. Summary of the Invention

[0003] The purpose of the present invention is to solve the above technical problems and provide a grain dryer. The improved grain dryer of the present application provides a drying layer, enabling the drying layer to have the effects of hot air reflux and reducing the impact on grains.

[0004] To achieve the above purpose, the technical solution of the present invention is as follows:

[0005] A grain dryer includes a grain inlet layer, a drying layer, a grain outlet layer, a conveyor and a elevator. The grain inlet layer, the drying layer, the grain outlet layer and the conveyor are connected in sequence from top to bottom. The conveyor is connected to the lower end of the elevator, and the upper end of the elevator is connected to the grain inlet layer. The drying layer includes a drying housing and a return air fan. The drying housing has a drying chamber, an air inlet chamber, an air outlet chamber and a return air chamber. A plurality of network tube-shaped air ducts are arranged vertically and spaced apart in the drying chamber. Under the lifting of the elevator, the grain circulates from top to bottom and enters the space between the network tube-shaped air ducts in the drying chamber for drying. A communicating air return opening is provided between the air inlet chamber and the return air chamber, and the return air fan is installed at the air return opening. A first air inlet is provided between the return air chamber and the drying chamber. The upper ends of some of the network tube-shaped air ducts are connected to the first air inlet, so that hot air enters from the air inlet chamber and is blown into the drying chamber by the return air fan. Air outlet openings are provided between the drying chamber and both the air inlet chamber and the air outlet chamber. The lower ends of some of the other network tube-shaped air ducts are respectively connected to the air inlet chamber and the air outlet chamber through the air outlet openings, so that part of the hot air is blown out from the air outlet chamber, and the other part of the hot air is attracted by the return air fan to form a hot air reflux.

[0006] According to the grain dryer of the present application, the horizontal angled boxes in the drying layer are omitted, and a new drying air duct structure is provided. The grain can fall directly without colliding with the vertically arranged network tube-shaped air ducts, reducing the number of collisions between the grain and hard objects, avoiding damage to the grain under external force during the drying process, reducing the cracking rate of the grain, and also avoiding the load-bearing and durability problems caused by the horizontal angled boxes due to the absence of the horizontal angled boxes; The hot air is blown into the drying chamber from the air inlet chamber, and is blown into the drying chamber from the upper ends of the network tube-shaped air ducts under the traction of the return air fan, and is blown into the space between the grains through the mesh holes on the network tube-shaped air ducts to dry the grain. Then, the hot air with water vapor is blown out from the air outlet opening. Part of the hot air is blown out from the air outlet chamber, and the other part of the hot air is attracted by the return air fan to form a hot air reflux to circulate and dry the grain in the drying layer. Therefore, the new drying air duct structure of the present application has the advantages of saving heat, improving the drying rate, and ensuring the quality of the grains.

[0007] Further, the drying housing includes a drying frame body, an air inlet frame body, an air outlet frame body and a return air frame body. The drying chamber, the air inlet chamber, the air outlet chamber and the return air chamber are correspondingly arranged in the drying frame body, the air inlet frame body, the air outlet frame body and the return air frame body. The drying frame body has a first side surface and a second side surface arranged opposite to each other. The air inlet frame body and the return air frame body are arranged on the first side surface, and the return air frame body is arranged above the air inlet frame body. The first air inlet is arranged on the first side surface. The air outlet frame body is arranged on the second side surface, and the air outlet openings are arranged on both the first side surface and the second side surface.

[0008] Furthermore, it further includes an upper mounting seat and a lower mounting seat. Both ends of the upper mounting seat and the lower mounting seat are fixed on the first side face and the second side face. The network management type air duct includes a network management type air inlet duct and a network management type air outlet duct. The upper end of the network management type air inlet duct is communicated with the first air inlet, and the lower end of the network management type air outlet duct is communicated with the air outlet. The upper end of the network management type air inlet duct is fixed on the upper mounting seat. The lower mounting seat is provided with a plug post, and the lower end of the network management type air outlet duct is plugged and installed in the plug post. Hot air enters from the upper end of the network management type air inlet duct, diffuses to the grains between the network management type air ducts through the mesh holes on the pipe wall of the network management type air inlet duct, dries the grains, and the moist hot air after drying enters through the mesh holes on the pipe wall of the network management type air outlet duct and is discharged from the air outlet to the drying chamber.

[0009] Furthermore, a first net plate is provided on the first side face and the second side face. The first net plate communicates the drying chamber with the air inlet chamber and the air outlet chamber. The air inlet chamber has a second air inlet, and a flow guide plate is provided in the air inlet chamber. The second air inlet is opposite to the flow guide plate, and the hot air entering from the second air inlet is guided to the return air fan. The moist hot air after drying the grains can also enter the air inlet chamber or the air outlet chamber from the mesh holes of the first net plate, improving the ventilation effect of the drying chamber.

[0010] Furthermore, it further includes a damper actuator and a temperature sensor. The temperature sensor is used to sense the drying temperature in the drying layer. The damper actuator is arranged on the air inlet frame body, and the damper actuator controls the opening degree according to the drying temperature. There will be a problem of too high temperature during the drying of the drying layer, especially when multiple grain dryers are used in series. The problem of too high temperature is even more serious, and too high temperature will lead to a decline in the quality of grains. Through the cooperation of the damper actuator and the temperature sensor, when it senses that the drying temperature is too high, the damper actuator is opened, so that the air with a lower temperature outside can enter the drying layer, thereby reducing the drying temperature and ensuring the drying quality of the grains.

[0011] Furthermore, the drying frame body also has a third side face and a fourth side face which are oppositely arranged. The third side face and the fourth side face are provided with drying wire racks. The drying wire racks are communicated with the first side face and the second side face. An observation cover is provided on the outer side face of the drying wire racks. Setting the drying wire racks can increase the ventilation effect of the drying layer, and the observation cover can facilitate observing the state of the grains in the drying layer.

[0012] Furthermore, it further includes an air duct connecting piece, and the air duct connecting piece connects adjacent network management type air ducts. The air duct connecting piece can make the structure of the network management type air duct more stable.

[0013] Furthermore, an air outlet fan is installed in the air outlet chamber. The power of the air outlet fan and the return air fan is the same, and the quantity ratio is air outlet fan∶return air fan = 2∶3.

[0014] Furthermore, a conical top is provided at the top of the drying chamber, and the conical top is arranged above the network tube-shaped air duct. The conical top can enable the grains to smoothly enter between the network tube-shaped air ducts.

[0015] Furthermore, the grain inlet layer is provided with a plurality of unit frames, and adjacent unit frames are spliced up and down. Fixed pull rods are provided on the opposite sides of the unit frames, and the height of the unit frame is 600 - 610 mm.

[0016] Furthermore, the bottom of the drying layer has an outlet, a collecting funnel is arranged at the position corresponding to the outlet on the grain outlet layer, and a grain pushing wheel is arranged at the outlet of the collecting funnel. Description of the Drawings

[0017] Figure 1 is a perspective view of the grain dryer of the present invention.

[0018] Figure 2 is a cross-sectional view of the grain dryer of the present invention.

[0019] Figure 3 is Figure 2 a partial enlarged view of

[0020] Figure 4 is a perspective view of the unit frame of the present invention.

[0021] Figure 5 is a perspective view of the drying layer of the grain dryer of the present invention.

[0022] Figure 6 is an exploded view of the drying layer of the grain dryer of the present invention.

[0023] Figure 7 is an exploded view of the drying frame of the grain dryer of the present invention.

[0024] Figure 8 is a perspective view of the grain outlet layer and the conveyor of the grain dryer of the present invention.

[0025] Figure 9 is a schematic structural diagram of the hot blast stove supplying hot air to the grain dryer of the present invention.

[0026] Figure 10 is a schematic air path diagram of the grain dryer of the present invention. Detailed Embodiments

[0027] A grain dryer of the present invention will be described in conjunction with the accompanying drawings.

[0028] As Figures 1 to 10A grain dryer as shown includes a grain inlet layer 1, a drying layer, a grain outlet layer 3, a conveyor 4 and an elevator 5. The grain inlet layer 1, the drying layer, the grain outlet layer 3 and the conveyor 4 are connected in sequence from top to bottom. The outlet 41 of the conveyor 4 is connected to the lower end of the elevator 5. The elevator 5 is also provided with a grain inlet 51 at its lower end. The grain inlet 51 can facilitate the input of the grain to be dried into the grain dryer. The upper end of the elevator 5 is provided with a plurality of outlets, which are connected to the grain inlet layer through a circulation port 53. The upper end of the elevator 5 is also provided with a grain outlet 52, and the grain outlet 52 can output the dried grain from the grain dryer. Under the lifting of the elevator 5, the grain circulates through the drying layer in the grain dryer, so as to dry the grain in a cycle, enabling the grain to be evenly dried and also avoiding the situation of broken rice caused by the grain being heated for a long time. The drying layer includes a drying housing 2 and a return air fan 7. The drying housing 2 has a drying chamber, an air inlet chamber, an air outlet chamber and a return air chamber. A plurality of network tube-shaped air ducts 25 are arranged at intervals vertically in the drying chamber. Under the lifting of the elevator 5, the grain circulates from top to bottom and enters between the network tube-shaped air ducts 25 in the drying chamber for drying. The grain can fall directly without colliding with the vertically arranged network tube-shaped air ducts 25, reducing the number of collisions between the grain and hard objects and avoiding the damage of the grain under external force during the drying process, reducing the cracking rate of the grain. A communicating return air port 223 is provided between the air inlet chamber and the return air chamber. The return air fan 7 is installed at the return air port 223. A first air inlet 215 is provided between the return air chamber and the drying chamber. The upper ends of some of the network tube-shaped air ducts 25 are connected to the first air inlet 215, so that the hot air enters from the air inlet chamber and is blown into the drying chamber by the return air fan 7. Communicating air outlets (2112, 2122) are provided between the drying chamber and both the air inlet chamber and the air outlet chamber. The lower ends of some of the other network tube-shaped air ducts 25 are respectively connected to the air inlet chamber and the air outlet chamber through the air outlets (2112, 2122), so that part of the hot air is blown out from the air outlet chamber, and the other part of the hot air is attracted by the return air fan 7 to form a hot air reflux. The grain dryer generates heat through a hot blast stove, and the hot blast stove is connected to the air inlet chamber through a draft fan. The draft fan draws the hot air and blows it into the air inlet chamber, and under the traction of the return air fan 7, it is blown into from the upper ends of the network tube-shaped air ducts 25 and blown into the grain through the mesh holes on the tube walls of the network tube-shaped air ducts 25 to dry the grain. Then the moist hot air is blown out from the air outlets (2112, 2122). Part of the hot air is blown out from the air outlet chamber, and the other part of the hot air is attracted by the return air fan 7 to directly form a hot air reflux in the drying layer to circulate and dry the grain in the drying chamber.

[0029] Such as Figures 5 to 7As shown, the drying housing 2 includes a drying frame 21, an air inlet frame 22, an air outlet frame 23 and a return air frame 24. The drying chamber, the air inlet chamber, the air outlet chamber and the return air chamber are correspondingly arranged in the drying frame 21, the air inlet frame 22, the air outlet frame 23 and the return air frame 24 respectively. The drying frame 21 has a first side surface 211 and a second side surface 212 which are oppositely arranged. The air inlet frame 22 and the return air frame 24 are arranged on the first side surface 211, and the return air frame 24 is arranged above the air inlet frame 22. The first air inlet 215 is arranged on the first side surface 211. The air outlet frame 23 is arranged on the second side surface 212. The air outlets (2112, 2122) are arranged on the first side surface 211 and the second side surface 212.

[0030] The network tube type air duct 25 includes a network tube type air inlet duct 251 and a network tube type air outlet duct 252. The upper end of the network tube type air inlet duct 251 is communicated with the first air inlet 215. The lower end of the network tube type air outlet duct 252 is communicated with the air outlets (2112, 2122). Hot air enters from the upper end of the network tube type air inlet duct 251 and diffuses to the grains between the network tube type air ducts 25 through the mesh holes on the pipe wall of the network tube type air inlet duct 251 to dry the grains. The moist hot air after drying enters through the mesh holes on the pipe wall of the network tube type air outlet duct 252 and is discharged from the air outlets (2112, 2122) out of the drying chamber. There are three rows of network tube type air inlet ducts 251 and two rows of network tube type air outlet ducts 252, and the two rows of network tube type air outlet ducts 252 are arranged at intervals between the three rows of network tube type air inlet ducts 251.

[0031] As Figures 5 to 7 shown, it further includes an upper mounting seat 27 and a lower mounting seat 28. There are three corresponding upper mounting seats 27 and two corresponding lower mounting seats 28. The two ends of the upper mounting seat 27 and the lower mounting seat 28 are fixed on the first side surface 211 and the second side surface 212 by bolts. The upper end of the network tube type air inlet duct 251 is fixed on the upper mounting seat 27 by bolts. The lower mounting seat 28 is provided with insertion columns, and the lower end of the network tube type air outlet duct 252 is inserted and installed in the insertion columns. A channel is formed in the lower mounting seat 28 to communicate the air outlets (2112, 2122) and the lower end of the network tube type air outlet duct 252.

[0032] As Figures 6 to 7As shown, first mesh plates (2111, 2121) are provided on the first side surface 211 and the second side surface 212. The mesh holes on the first mesh plates (2111, 2121) connect the drying chamber with the air inlet chamber and the air outlet chamber. The air inlet chamber has a second air inlet 221, and a flow guide plate 222 is provided in the air inlet chamber. The second air inlet 221 faces the flow guide plate 222, guiding the hot air entering from the second air inlet 221 towards the return air fan 7. The moist hot air after drying the grains can also enter the air inlet chamber or the air outlet chamber through the mesh holes of the first mesh plates (2111, 2121), improving the ventilation effect of the drying chamber. The induced draft fan of the hot blast stove faces the second air inlet 221, thus blowing the hot air into the air inlet chamber. The setting of the flow guide plate 222 can guide the hot air blown into the air inlet chamber towards the return air fan 7. Moreover, the air outlet openings (2112, 2122) connecting the air inlet chamber also face the flow guide plate 222, and the flow guide plate 222 guides the reflux hot air towards the return air fan 7, thereby forming a hot air reflux in the drying layer.

[0033] As Figure 1 shown, it further includes a damper actuator 6 and a temperature sensor. Both the damper actuator 6 and the temperature sensor are commercially available products. The damper actuator 6 preferably adopts a multi-leaf damper. The temperature sensor is used to sense the drying temperature in the drying layer. The damper actuator 6 is arranged on the air inlet frame 22, and the damper actuator 6 controls the opening degree according to the drying temperature. When drying the grains, there will be a problem of too high temperature in the drying layer, especially when multiple grain dryers are used in series. The problem of too high temperature is even more serious, and too high temperature will lead to a decline in the quality of the grains. Through the cooperation of the damper actuator 6 and the temperature sensor, when it senses that the drying temperature is too high, the damper actuator 6 is opened, so that the air with a lower temperature outside can enter the drying layer, thereby reducing the drying temperature and ensuring the drying quality of the grains. When drying the grains, there is a relatively appropriate drying temperature. Drying the grains at this temperature can make the quality of the dried grains better. First, the drying stability (hereinafter referred to as the set temperature) will be set before drying the grains. When starting to dry the grains and let in the air, since the air has just started to enter and the temperature in the drying layer has not reached the set temperature yet, at this time the damper actuator 6 is closed. When the set temperature is reached, the damper actuator is opened, enabling the external cold air to enter the drying layer. When the drying temperature in the drying layer is still rising, the opening degree of the damper actuator 6 is further increased, and vice versa, the opening degree of the damper actuator 6 is decreased.

[0034] As Figure 7As shown, the drying frame 21 is generally rectangular in shape as a whole. The drying frame 21 also has a third side surface 213 and a fourth side surface 214 that are oppositely arranged. The drying wire racks 26 are provided on the third side surface 213 and the fourth side surface 214. The drying wire racks 26 are communicated with the first side surface 211 and the second side surface 212. An observation cover 261 is provided on the outer side surface of the drying wire rack 26. The observation cover 261 is a detachable or transparent cover body, so that the state of the grains in the drying layer can be conveniently observed. The drying wire rack 26 also includes a second wire mesh plate 263 and a frame body 262. The second wire mesh plate 263 can ventilate and does not affect the observation of the state of the grains by the observation cover 261. The frame body 262 provides support for the second wire mesh plate 263 and forms a ventilated space.

[0035] As Figure 2 shown, an air outlet fan 8 is installed in the air outlet cavity. The air outlet fan 8 and the return air fan 7 have the same power, and the quantity ratio is air outlet fan 8∶return air fan 7 = 2∶3, which can ensure that the wind force generated by the return air fan 7 is greater than the air outlet wind force of the air outlet cavity. According to the attached drawings, it can be determined that in the embodiment shown in the attached drawings of the present application, 3 return air fans 7 and 2 air outlet fans 8 are provided.

[0036] As Figure 2 and Figure 4 shown, a conical top 29 is provided at the top of the drying cavity. The conical top 29 is arranged above the network pipe type air duct 25. The conical top 29 enables the grains to smoothly enter between the network pipe type air ducts 25. The conical top 29 includes two types of conical tops 29 with different sizes. Three larger conical tops 29 are provided. The conical top 29 covers the upper mounting seat 27 of the three rows of network pipe type air inlet pipes 251 and forms a channel connecting the first air inlet 215 and the upper end of the network pipe type air inlet pipe 251. Two smaller conical tops 29 are provided. The conical top 29 covers the two rows of network pipe type air outlet pipes 252. The top of the lower mounting seat 28 is also set as a conical surface to prevent the grains from accumulating on the lower mounting seat 28.

[0037] As Figure 4 shown, the grain inlet layer 1 is provided with a plurality of unit frames 11. The adjacent unit frames 11 are spliced up and down. Fixed pull rods 12 are provided on the opposite side surfaces of the unit frames 11. By calculating the specific gravity of the grains, the corresponding number of pull rods 12 is set. Through the reinforcement of the pull rods 12, the structure of the grain inlet layer 1 can be made more stable. And the size of the pull rods 12 is relatively thin and will not cause blockage of the grains. The height of the unit frame 11 is 600 - 610 mm. Generally, the original plate with a height of 1224 mm is used to process the unit frame. Therefore, setting the height of the unit frame 11 to 600 - 610 mm can improve the utilization rate of the plate.

[0038] Multiple tie rods can also be provided between the first side surface 211 and the second side surface 212 for connection and reinforcement, making the structures of the first side surface 211 and the second side surface 212 more stable.

[0039] As Figure 3 and Figure 8 shown, the bottom of the drying layer has an outlet. The housing of the drying layer is formed in a large funnel shape, and the bottom of the funnel is the outlet. A collecting funnel 31 is provided at the position of the grain outlet layer 3 corresponding to the outlet. A grain distributing wheel 32 is provided at the outlet of the collecting funnel 31. A conical top 29 is also provided at the outlet above the collecting funnel. The grain is guided into the collecting funnel 31 through the conical top 29.

[0040] The mesh holes of this application are all smaller than the size of the grains, enabling it to be used for ventilation while preventing the grains from leaking out through the mesh holes.

[0041] This application also tests the drying structure to verify the improvement of the drying efficiency and the reduction of energy consumption of the drying structure of this application.

[0042] The first group of experiments:

[0043] 1. Test grouping

[0044] Control group: A grain dryer using a traditional horizontal angled box drying layer

[0045] Experimental group: A grain dryer using the drying layer of this application

[0046] 2. Experimental conditions

[0047] Grain type: Paddy rice (initial moisture content 25%)

[0048] Weight: 30 tons

[0049] Target moisture content: 13.5%

[0050] Drying temperature: 65°C

[0051] Air volume: 14000m 3 / h (the same for both groups)

[0052] 3. Data collection

[0053] Record the time required to reach the target moisture content;

[0054] Measure the energy consumption of the hot blast stove.

[0055] Experimental results:

[0056] Group Drying time (hours) Heat consumption (kcal / kg) Control group 13.2 4435200 Experimental group 9.8 3292800

[0057] Analysis conclusion:

[0058] The drying efficiency of the experimental group increased by 25.76%, and the energy consumption decreased by 25.76%, indicating that the structural design of this application significantly optimized the thermal energy utilization rate.

[0059] The second group of experiments:

[0060] 1. Test grouping

[0061] Control group: A grain dryer using a traditional horizontal angled box drying layer

[0062] Experimental group: A grain dryer using the drying layer of this application

[0063] 2. Experimental conditions

[0064] Grain type: Paddy rice (initial moisture content 27%)

[0065] Weight: 28 tons

[0066] Target moisture content: 14%

[0067] Drying temperature: 65 °C

[0068] Air volume: 14000m 3 / h (the same for both groups)

[0069] 3. Data collection

[0070] Record the time required to reach the target moisture content;

[0071] Measure the energy consumption of the hot blast stove.

[0072] Experimental results:

[0073] Group Drying time (hours) Heat consumption (kcal / kg) Control group 15.1 5073600 Experimental group 11.3 3796800

[0074] Analysis conclusion

[0075] The drying efficiency of the experimental group increased by 25.16%, and the energy consumption decreased by 25.16%, indicating that the structural design of this application significantly optimized the thermal energy utilization rate.

[0076] According to the disclosure and teachings of the above specification, those skilled in the art to which the present invention pertains can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A grain dryer, characterized in that: The invention comprises a grain feeding layer, a drying layer, a grain discharging layer, a conveyor and an elevator. The grain feeding layer, the drying layer, the grain discharging layer and the conveyor are connected in sequence from top to bottom. The conveyor is connected to the lower end of the elevator. The upper end of the elevator is connected to the grain feeding layer. The drying layer comprises a drying shell and a return air fan. The drying shell is provided with a drying chamber, an air inlet chamber, an air outlet chamber and a return air chamber. The drying chamber is provided with a plurality of mesh tube-type air ducts arranged at vertical intervals. Under the lifting of the elevator, the grain circulates from top to bottom and enters the mesh tube-type air ducts of the drying chamber for drying. The air inlet chamber and the return air chamber are provided with a plurality of mesh tube-type air ducts arranged at vertical intervals. A connected return air port is provided between the air chambers, the return air fan is installed at the return air port, a first air inlet is provided between the return air chamber and the drying chamber, the upper end of a part of the mesh tube type air duct is connected with the first air inlet, so that hot air enters from the air inlet chamber and is blown into the drying chamber by the return air fan, and a connected air outlet is provided between the drying chamber and the air inlet chamber and the air outlet chamber, and the lower end of another part of the mesh tube type air duct is connected with the air inlet chamber and the air outlet chamber through the air outlet, so that part of the hot air is blown out from the air outlet chamber, and the other part of the hot air is attracted by the return air fan to form a hot air reflux.

2. The grain dryer according to claim 1, characterized in that: The drying shell includes a drying frame, an air inlet frame, an air outlet frame and a return air frame, the drying chamber, the air inlet chamber, the air outlet chamber and the return air chamber are correspondingly arranged in the drying frame, the air inlet frame, the air outlet frame and the return air frame, the drying frame has a first side surface and a second side surface which are arranged opposite to each other, the air inlet frame and the return air frame are arranged on the first side surface, and the return air frame is arranged on the upper part of the air inlet frame, the first air inlet is arranged on the first side surface, the air outlet frame is arranged on the second side surface, and the air outlet is arranged on the first side surface and the second side surface.

3. The grain dryer according to claim 2, characterized in that: It also includes an upper mounting seat and a lower mounting seat, both ends of which are fixed on the first side and the second side, and the mesh tube type air duct includes a mesh tube type air inlet pipe and a mesh tube type air outlet pipe, the upper end of the mesh tube type air inlet pipe is connected to the first air inlet, and the lower end of the mesh tube type air outlet pipe is connected to the air outlet. The upper end of the mesh tube type air inlet pipe is fixed on the upper mounting seat, and the lower mounting seat is provided with a plug-in column, and the lower end of the mesh tube type air outlet pipe is plugged and installed in the plug-in column.

4. The grain dryer according to claim 2, characterized in that: A first mesh plate is provided on the first side and the second side, and the first mesh plate connects the drying chamber with the air inlet chamber and the air outlet chamber. The air inlet chamber has a second air inlet, and a guide plate is provided in the air inlet chamber. The second air inlet is opposite to the guide plate, and the hot air entering from the second air inlet is guided to the return air fan.

5. The grain dryer according to claim 2, characterized in that: It also includes a damper actuator and a temperature sensor, wherein the temperature sensor is used to sense the drying temperature in the drying layer, and the damper actuator is arranged on the air inlet frame, and the damper actuator controls the opening according to the drying temperature.

6. The grain dryer according to claim 2, characterized in that: The drying frame also has a third side surface and a fourth side surface that are arranged opposite to each other. The third side surface and the fourth side surface are provided with a drying grid rack that is connected to the first side surface and the second side surface. An observation cover is provided on the outer side surface of the drying grid rack.

7. The grain dryer according to claim 1, characterized in that: The air outlet cavity is equipped with an air outlet fan, and the power of the air outlet fan and the return air fan are the same, and the number ratio is air outlet fan:return air fan=2:

3.

8. The grain dryer according to claim 1, characterized in that: A conical top is provided on the top of the drying chamber, and the conical top is arranged on the mesh tube type air duct.

9. The grain dryer according to claim 1, characterized in that: The food feeding layer is provided with a plurality of unit frames, and the adjacent unit frames are spliced ​​up and down. The relative sides of the unit frames are provided with fixed pull rods, and the height of the unit frames is 600-610mm.

10. The grain dryer according to claim 1, characterized in that: The bottom of the drying layer is provided with an outlet, the grain discharging layer is provided with a collecting funnel at a position corresponding to the outlet, and a grain shifting wheel is provided at the outlet of the collecting funnel.

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