Low-temperature grain storage system and grain transfer control method thereof

Abstract

The present application relates to a kind of low-temperature grain storage transport control method and a kind of low-temperature grain storage system, belong to grain storage transport technical field, solve the existing in the grain storage summer transport, prone to grain surface dew phenomenon, and affect the further processing of grain problem.The technical scheme adopted is: by setting pre-warming bin in main grain storehouse, setting slow release bin and heat exchange device in slow release bin, by the way of multi-stage slow heating to realize the change of grain from low temperature to high temperature, pay attention to control the amplitude of temperature rise in the process of temperature rise, to ensure that the surface of grain will not dew in the process of transport, so as to meet the subsequent processing needs of grain well.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of low-temperature grain storage system grain transfer control method, for the grain in low temperature state is realized using the way of gradually heating, under the premise of no dew, the transfer of grain.This application also relates to a low-temperature grain storage system. BACKGROUND

[0002] Low-temperature grain storage is a relatively safe way of storing grain, which keeps grain at a low temperature of about 15 degrees Celsius. Low-temperature grain storage can not only inhibit the respiratory metabolism of grain, delay the aging of grain quality, effectively maintain the vitality and freshness of grain, reduce grain storage loss, but also effectively control the activities and damage of pests and microorganisms in stored grain, reduce the use of chemical pesticides, and is beneficial to maintaining grain hygiene and reducing environmental pollution.

[0003] Low-temperature grain storage technology also has a series of problems in practical application, especially in the summer season, when the grain in low temperature state is discharged, due to the large temperature difference between indoor and outdoor, the surface of the grain in low temperature state will condense water vapor in the air due to the temperature difference when it is suddenly transported to the outdoor, and dew will form quickly, which will affect the subsequent storage of grain and easily lead to grain deterioration or affect the further processing of grain.

[0004] Chinese patent document (publication number: CN 104813816A) discloses a multi-layer partition heat insulation ventilation low-temperature grain storage warehouse and its temperature control method, which uses the air between the top of the closed grain warehouse and the heat insulation layer for heat insulation, and then uses the increased partition heat insulation layer on the upper layer of the grain pile to guide the cold source outside the grain warehouse into the heat preservation, so that the air between the upper layer of the grain pile and the heat insulation plate is in low temperature, thereby making the grain be stored in low temperature or quasi-low temperature all year round. The control instrument automatically controls the start and stop of the cold source and the axial flow fan, opens and closes the sealing door and adjusts the opening degree of the door, thereby realizing the automatic ventilation and temperature control of the grain storage warehouse. The cold air flows independently in the closed compartment without direct contact with the grain layer, which fundamentally eliminates dew, effectively maintains the quality of stored grain, reduces the management risk and cost, and realizes the goal of green grain storage.

[0005] This temperature control method can control the temperature in the grain warehouse, but it does not consider the temperature control of the grain when it is discharged, so the surface of the grain is easy to accumulate dew when it is discharged, which may affect the further operation of the grain. SUMMARY

[0006] One of the technical problems to be solved by the present application is to provide a low-temperature grain storage system grain transfer control method, which can effectively prevent the phenomenon of dew on the surface of the grain when it is discharged, and facilitate the operation of the grain.

[0007] Another technical problem to be solved by the present application is to provide a low-temperature grain storage system which can conveniently realize grain non-condensation exposure to the outside.

[0008] The technical solution adopted to solve the above technical problems is a low-temperature grain storage system grain transfer control method for realizing transfer of grain in low-temperature storage to an external high-temperature environment, characterized in that a stepwise heating mode is adopted to raise the temperature of the low-temperature grain to be close to or equal to the temperature of the external environment, and finally realize discharge; the heating range is determined according to the moisture content of the grain, under the precondition that the grain does not condense during the transfer process.

[0009] The grain storage system involved includes a main grain storehouse, a buffer storehouse and a material collecting structure, the pre-warming bin is arranged at the upper end of the main grain storehouse, the buffer bin is arranged in the buffer storehouse, and the heat exchange device is arranged on the outer periphery of the buffer bin.

[0010] During grain transfer, the grain in the main grain storehouse is allowed to enter the pre-warming bin to be closed and stationary for a period of time, the grain in the pre-warming bin is then allowed to enter the buffer bin to be closed and stationary for a period of time, the temperature in the buffer bin is gradually raised through the heat exchange device, and then the grain is transported out through the material collecting structure.

[0011] The main conditions for grain condensation are temperature difference and reaching dew point (temperature at which condensation begins). Generally, the greater the temperature difference, the more serious the condensation. In addition, when the moisture content of the grain is greater, or the moisture content of the air is greater, the dew point is closer to the temperature of the environment in which the grain is located, the water vapor is more likely to reach saturation, and the condensation phenomenon is more likely to occur. See the following table:

[0012] Grain moisture (wt%) 10 11 12 14 15 16 17 18 Dew point temperature difference (°C) 12-14 10-12 8-10 6-7 4-5 3-4 2 1

[0013] The test data in the table show that, to realize non-condensation, the gradual heating range of the grain needs to be determined in combination with the condition of the grain itself and the environmental factors. That is, when the moisture content of the grain is the value in the top row of the table, attention needs to be paid to the heating range during the heating process. To achieve non-condensation of the grain during the heating process, the grain needs to be stationary for a relatively long time at different stages, there is heat exchange between the environment and the grain, the temperature of the grain needs to be consistent with or close to that of the environment, and the possible time length of each stage is a few hours at the least and up to more than 10 hours. When the moisture content of the grain reaches 17% and 18%, it takes more than 48 hours to complete the entire transfer process. When the grain is stationary in a certain environment for a long time, the grain absorbs water in the case of high humidity of the air, and the moisture in the grain evaporates in the case of low humidity of the air. Ultimately, the humidity of the environment corresponds to the moisture content of the grain. Therefore, only the humidity of the environment needs to be detected, and the moisture content of the grain can be reflected.

[0014] The main grain storehouse is provided with a cooling system to maintain the temperature in the main grain storehouse at a low temperature. The main grain storehouse is also provided with a temperature and humidity sensor to display the environmental parameters in the main grain storehouse, thereby providing a reference for the temperature drop range of the grain. The outer walls of the pre-warming bin and the slow-release bin are provided with a thermal insulation layer to avoid or reduce heat exchange between them and the outside. The pre-warming bin and the slow-release bin are also provided with a temperature and humidity sensor to detect the environmental parameters, thereby providing a reference for the temperature rise range. The temperature rise range is detected by temperature sensors arranged in the heat exchange device and the corresponding bin, and the temperature difference detected by the two sensors is used to determine the temperature rise range.

[0015] The main grain storehouse, the slow-release bin and the collecting structure are usually connected by a material guide pipe, and a thermal insulation layer is arranged on the outer periphery of the material guide pipe to prevent heat exchange between the material guide pipe and the outside, and to allow the environmental temperature in the material guide pipe to be in contact with the temperature of the grain itself. Before the grain is transported, the corresponding bin needs to be connected to make the initial environmental parameters in the two adjacent bins basically the same. However, when the grain enters the downstream bin, the connection between the bins needs to be cut off to allow the grain to be stationary in the target bin. The connection between the bins is usually achieved by a door structure, and opening the corresponding door allows the connection, and closing the corresponding door allows the disconnection. The opening and closing of the door is usually achieved by an electric control mechanism.

[0016] Further, the temperature in the pre-warming bin is raised by arranging a pre-warming device on the periphery of the pre-warming bin. The pre-warming bin is arranged at the top end of the main grain storehouse, and the temperature in the pre-warming bin is slightly higher than the temperature of the grain at the low end of the main grain storehouse. After the grain enters the pre-warming bin, the pre-warming device is started to raise the temperature in the pre-warming bin. The grain is stationary until its temperature approaches the temperature in the pre-warming bin. The pre-warming device is started again to raise the temperature in the pre-warming bin by a certain temperature rise range. Then the grain is stationary again until its temperature approaches the temperature in the pre-warming bin. This process is repeated until the grain reaches the target temperature and is input into the slow-release bin.

[0017] Further, the heat exchange device uses hot air from the outside as a heat transfer medium, and under the action of the air supply system, the temperature in the slow-release bin is raised. The heat exchange device of this structure is simple in structure, low in cost and easy to realize the temperature in the bin approaching the outside temperature.

[0018] Further, the collecting structure includes a collecting hopper, and the collecting hopper is provided with a collecting bin. The heat exchange device is also arranged on the periphery of the collecting bin in the collecting hopper. The grain in the slow-release bin needs to be stationary for a certain period of time before being discharged after entering the collecting bin. By arranging the heat exchange device in the collecting hopper, the grain entering the collecting hopper can be gradually heated, the temperature rise range of the grain is improved, and the grain can be raised to the target temperature.

[0019] Further, the vertical lifting mechanism is arranged in the main grain storehouse, and the grain is promoted into the pre-warming bin through the lifting mechanism; the periphery of the pre-warming bin is provided with a heat preservation layer, a liquid bath cavity is formed between the heat preservation layer and the bin wall of the pre-warming bin, the annular and hollow heat pipe is wrapped around the periphery of the pre-warming bin in the liquid bath cavity, and the heat pipe is spaced apart from the bin wall of the pre-warming bin; the heat pipe is connected to the fan, and under the driving of the fan, the external air flows in the heat pipe. The liquid bath cavity is pre-injected with water, and the liquid is used as a heat conduction medium, so that the heat transfer is uniform and slow, and the slow temperature rise requirement of the grain can be well met.

[0020] Further, the periphery of the slow-releasing bin is provided with a heat exchange device, the structure of the heat exchange device comprises a heat exchange bin wrapped around the periphery of the slow-releasing bin, and the wall body of the heat exchange bin is provided with an air inlet and an air outlet; and the external air is made to flow into the heat exchange bin through the fan. The structure of the heat exchange device is simple, directly uses the external air as a heat source, has high operation efficiency, and has low operation cost.

[0021] Further, the heat exchange bin comprises an inner bin and an outer bin arranged coaxially, the wall body of the inner bin is provided with an inner air inlet and an inner air outlet, respectively, and the inner air inlet and the inner air outlet are located in the diameter direction of the inner bin; the wall body of the outer bin is provided with an outer air inlet and an outer air outlet, respectively, and the outer air inlet and the outer air outlet are located in the diameter direction of the outer bin; and the inner air inlet, the inner air outlet, the outer air inlet and the outer air outlet are arranged in a cross shape. This is beneficial to slow heat exchange between the inner bin and the outer bin, and facilitates slow temperature rise in the corresponding bin.

[0022] Further, the lifting mechanism comprises a vertical conduit, the auger is rotatably arranged in the conduit, and a plurality of support columns are arranged at the lower end of the conduit at intervals. When the grain is transported, the grain enters the conduit from the intervals between the support columns. The lifting mechanism has simple structure, high working efficiency, and is convenient for realizing the transportation of the grain.

[0023] Compared with the prior art, the present application has the following advantages: the grain is transported by using the staged temperature rise method, the slow temperature rise of the grain is realized according to the environment of the grain, the surface of the grain is not required to be dewed during the temperature rise process, the surface condition of the grain is good after the grain is discharged, and the subsequent processing and treatment of the grain or the storage of the grain in another warehouse are facilitated. By arranging some functional bins in the low-temperature grain storage system, the slow temperature rise of the grain is realized by the static method, the structure is simple, and the operation is convenient. Through the flow of the grain in different bins, the grain pile is changed, the stirring effect is achieved, and the temperature of the grain is uniformly raised. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a structure diagram of the low-temperature grain storage system.

[0025] Figure 2 is the structure diagram of vertical lifting mechanism.

[0026] Figure 3 is the cross-sectional structure diagram of pre-warming bin.

[0027] Figure 4 is the cross-sectional structure diagram of slow-release bin.

[0028] In the figure: 1, main grain storehouse; 2, motor; 3, material guide pipe; 4, slow-release bin; 5, material collecting hopper; 6, guide pipe; 7, auger; 8, support column; 9, thermal insulation layer; 10, liquid bath cavity; 11, pre-warming bin; 12, heat pipe; 13, slow-release bin; 14, outer bin; 15, inner bin; 16, grain distribution storehouse. DETAILED DESCRIPTION

[0029] In combination with the drawings of the specification, the grain transfer control method of the low-temperature grain storage system is used to realize the transfer of the grain in low-temperature storage to the high-temperature environment outside. During the transfer of the grain, the transfer amount is usually in tons. During the transfer, the step-by-step heating method is adopted to raise the temperature of the low-temperature grain to be close to or equal to the temperature of the environment outside, and finally realize the discharge of the grain. During the heating process, the heating range is determined according to the moisture content of the grain, and the grain does not condense during the transfer.

[0030] The transfer control method needs to be realized in combination with the structure of the grain storage system. Figure 1 The grain storage system includes a main grain storehouse 1, a slow-release bin 4 and a material collecting structure. The main grain storehouse 1 is a vertical round bin structure, with a diameter of 20-40 m and a height of 12-15 m, and a capacity of 6000-10000 t. A pre-warming bin 11 is arranged at the upper end of the main grain storehouse 1, and a slow-release bin 13 is arranged in the slow-release bin 4. The outer periphery of the slow-release bin 13 is provided with a heat exchange device. A grain distribution storehouse 16 is further arranged outside the main grain storehouse 1 to make up for the insufficient capacity of the main grain storehouse 1, or a small amount of residual old grain in the main grain storehouse 1 can be discharged to empty the main grain storehouse 1 to receive new grain. The main grain storehouse 1 and the grain distribution storehouse 16 are communicated through the inclined material guide pipe 3, and the grain can be sent into the inlet of the material guide pipe 3 through the air suction conveyor and freely fall into the grain distribution storehouse 16. The material guide pipe 3 is also arranged between the main grain storehouse 1 and the slow-release bin 4, and similar structures are also arranged between the slow-release bin 4 and the discharge structure to realize the transfer of the grain between the bins.

[0031] When the grain is transported, the grain in the main grain storehouse 1 is put into the pre-warming bin 11, the passageway between the pre-warming bin 11 and other structures is closed, and a closed environment is created, so that the grain is closed and static in the pre-warming bin 11 for a period of time. When the temperature of the grain is equal to or close to the temperature in the pre-warming bin 11, the pre-warming bin 11 is communicated with the downstream buffer bin 13, after the two are communicated, the environment in the pre-warming bin 11 and the environment in the buffer bin 13 are neutralized, so that the temperature of the environment in the buffer bin 13 at this time is not much different from the temperature of the environment in the pre-warming bin 11, then, the grain in the pre-warming bin 11 is put into the buffer bin 13 to be closed and static for a period of time, and the temperature in the buffer bin 13 is gradually increased through the heat exchange device. Then the grain is transported out through the material collecting structure.

[0032] The temperature in the pre-warming bin 11 is increased by setting a pre-warming device around the pre-warming bin 11. The pre-warming device can be directly communicated with the outside, and the air inlet is set by setting a damper at the air inlet, and the amount of outdoor air entering is controlled by changing the opening of the damper, so as to slowly increase the temperature of the grain.

[0033] The heat exchange device can also be communicated with the outside through the air inlet, and the amount of air entering is controlled by setting the air inlet and the damper, so as to slowly increase the temperature of the grain. Regardless of the structure, in order to simplify the structure and reduce the operation cost, the heat exchange device uses the hot air outside as the heat transfer medium, and under the action of the air supply system, the temperature in the buffer bin 13 is increased. The material collecting structure includes a material collecting hopper 5, which is arranged on the support in a suspended manner, and a material collecting bin is arranged in the material collecting hopper 5. The heat exchange device is also arranged around the material collecting bin in the material collecting hopper 5, and the grain in the buffer bin 13 needs to be closed and static for a period of time before being discharged into the material collecting bin.

[0034] The low-temperature grain storage system also includes a vertical lifting mechanism arranged in the main grain storehouse 1, which promotes the automatic entry of the grain into the pre-warming bin 11. Figure 2 The lifting mechanism includes a vertical guide pipe 6, and an auger 7 is coaxially rotatably arranged in the guide pipe 6. A plurality of support columns 8 are arranged at the lower end of the guide pipe 6. The support columns 8 are used to support the ground of the main grain storehouse 1, and the space between the support columns 8 is used for the grain to enter and contact the auger 7. A motor 2 is arranged at the upper end of the guide pipe 6, and the motor 2 drives the rotation of the auger 7, so as to realize the lifting of the grain.

[0035] See Figure 3In the periphery of the pre-warming bin 11 is provided with a heat preservation layer 9, and a liquid bath cavity 10 is formed between the heat preservation layer 9 and the bin wall of the pre-warming bin 11, and the liquid bath cavity 10 is filled with water. A hollow heat pipe 12 is arranged in the liquid bath cavity 10, the heat pipe 12 is annular and wrapped around the periphery of the liquid bath cavity 10, and the heat pipe 12 has a spacing with the bin wall of the pre-warming bin 11. The wall body between the liquid bath cavity 10 and the pre-warming bin 11 is a metal plate and can conduct heat. Both ends of the heat pipe 12 extend to the outside of the heat preservation layer 9, and the heat pipe 12 is connected to a fan. Under the driving of the fan, external air flows in the heat pipe 12, thereby slowly warming the water in the liquid bath cavity 10. The temperature change detected by the temperature sensor arranged in the liquid bath cavity 10 controls the operation of the fan, so that the temperature rise of the liquid in the liquid bath cavity 10 is within a suitable range. When there is no grain in the pre-warming bin 11, the heat pipe 12 is closed to cut off the communication with the external environment. The pre-warming bin 11 and the main grain storehouse 1 are communicated through the structure on the lifting mechanism, and the internal environments of the pre-warming bin 11 and the main grain storehouse 1 are close to each other in a very short time.

[0036] Figure 4 A cross-sectional view of a heat exchange device is shown in FIG. 6. In the periphery of the tempering bin 13 is provided with a heat exchange device, and the structure of the heat exchange device includes a heat exchange bin wrapped around the periphery of the tempering bin 13. An air inlet and an air outlet are formed on the wall body of the heat exchange bin. External air is made to flow into the heat exchange bin through a fan. The wall body between the heat exchange bin and the tempering bin 13 is made of metal and can conduct heat. The heat exchange bin includes an inner bin 15 and an outer bin 14 arranged coaxially. An inner air inlet and an inner air outlet are formed on the wall body of the inner bin 15, and the inner air inlet and the inner air outlet are located in the diameter direction of the inner bin 15. An outer air inlet and an outer air outlet are formed on the wall body of the outer bin 14, and the outer air inlet and the outer air outlet are located in the diameter direction of the outer bin 14. The inner air inlet, the inner air outlet, the outer air inlet, and the outer air outlet are arranged in a cross shape.

[0037] To realize the operation of the low-temperature grain storage system, a PLC controller is mainly used to realize automatic control. According to the data detected by the internal temperature and humidity sensor, the corresponding mechanism is instructed to work to realize automatic temperature rise and grain circulation.

Claims

1. A grain transfer control method for a low-temperature grain storage system, used to transfer grain stored at low temperatures to an external high-temperature environment, characterized in that: The low-temperature grains are heated to the temperature close to or equal to the ambient temperature by the step heating, and finally discharged; the heating range is determined according to the moisture content of the grains, and the grains are not allowed to dew in the process; The grain storage system comprises a main grain storehouse, a buffer storehouse and a collecting structure, a pre-heating bin is arranged at the upper end of the main grain storehouse, and a buffer bin is arranged in the buffer storehouse, and a heat exchange device is arranged on the outer periphery of the buffer bin; When the grains are transported, the grains in the main grain storehouse are allowed to enter the pre-heating bin and be closed and rested for a period of time, then the grains in the pre-heating bin are allowed to enter the buffer bin and be closed and rested for a period of time, the temperature in the buffer bin is gradually increased by the heat exchange device, and then the grains are transported out through the collecting structure; The temperature in the pre-heating bin is increased by arranging a pre-heating device on the outer periphery of the pre-heating bin; The heat exchange device uses the hot air outside as the heat transfer medium, and the temperature in the buffer bin is increased under the action of the air supply system; A vertical lifting mechanism is arranged in the main grain storehouse, and the grains are allowed to enter the pre-heating bin through the lifting mechanism; An insulation layer is arranged on the outer periphery of the pre-heating bin, a liquid bath cavity is formed between the insulation layer and the bin wall of the pre-heating bin, a ring-shaped and hollow heat pipe is wrapped around the outer periphery of the pre-heating bin in the liquid bath cavity, the heat pipe is spaced apart from the bin wall of the pre-heating bin, and the heat pipe is connected to a fan, so that the outside air flows in the heat pipe under the driving of the fan; A heat exchange device is arranged on the outer periphery of the buffer bin, and the structure of the heat exchange device comprises a heat exchange bin wrapped around the outer periphery of the buffer bin, and an air inlet and an air outlet are arranged on the wall of the heat exchange bin, so that the outside air flows into the heat exchange bin through the fan; The heat exchange bin comprises an inner bin and an outer bin arranged coaxially, an inner air inlet and an inner air outlet are arranged on the wall of the inner bin, and the inner air inlet and the inner air outlet are located in the diameter direction of the inner bin; an outer air inlet and an outer air outlet are arranged on the wall of the outer bin, and the outer air inlet and the outer air outlet are located in the diameter direction of the outer bin; and the inner air inlet, the inner air outlet, the outer air inlet and the outer air outlet are arranged in a "cross" shape.

2. The transit control method according to claim 1, wherein, The collecting structure comprises a collecting hopper, a collecting bin is arranged in the collecting hopper, and the heat exchange device is also arranged on the outer periphery of the collecting bin in the collecting hopper, so that the grains in the buffer bin are allowed to enter the collecting bin and be closed and rested for a period of time before being discharged.

3. The transit control method according to claim 1, wherein, The lifting mechanism comprises a vertical guide pipe, and a screw conveyor is rotatably arranged in the guide pipe, and a plurality of spaced-apart support columns are arranged at the lower end of the guide pipe.

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