A multi-functional ventilation system for low-temperature grain storage with intelligent linkage and its ventilation method

Abstract

The present invention discloses an intelligent linkage low-temperature grain storage multi-functional ventilation system and its ventilation method, which includes a ventilation pipe network, a main controller, and several refrigeration and air-conditioning units, temperature sensors, etc. connected to the main controller. The ventilation pipe network includes an upper-layer annular ventilation duct, a bottom-of-bunker ventilation floor grille, a vertical ventilation duct along the corner of the bunker wall, etc. Among them, the upper-layer annular ventilation duct is installed parallel to the ground below the grain loading line on the side wall of the granary; the bottom-of-bunker ventilation floor grille includes a lower-layer annular ventilation floor grille and a semi-circular cross-section ventilation floor grille arranged in a "mountain" shape; the vertical ventilation duct along the corner of the bunker wall has an isosceles triangle cross-section, one group of which is connected to the upper-layer annular air duct, and the other group is connected to the lower-layer annular floor grille. A closed air valve is provided on each branch air duct, and the opening and closing are controlled by the main controller according to the requirements of different grain storage temperature control working conditions; the present invention can systematically solve the problem of grain storage loss caused by reasons such as "local heating", "blind ventilation", and "cold core and hot skin" during storage.

Description

Technical Field

[0001] The present invention relates to the technical field of grain storage, and in particular to a multi-functional ventilation system for low-temperature grain storage with intelligent linkage and its ventilation method. Background Art

[0002] Low-temperature grain storage is a recognized green grain storage method in modern storage technologies. It uses natural cold sources in low-temperature seasons or refrigeration equipment, etc. to cool the grain pile in the warehouse, so that the grain temperature is in a relatively low state (the average grain temperature is lower than 15°C, and the local maximum temperature does not exceed 20°C), in order to inhibit the occurrence and development of aging, deterioration, insects and mildew, and achieve the purpose of safe grain storage.

[0003] Currently, to meet the requirements of low-temperature grain storage, grain depot managers mainly control the opening and closing of fans and refrigeration equipment manually or automatically at regular intervals according to the requirements of the "Technical Regulations for Mechanical Ventilation of Grain Storage" to achieve grain temperature control. To improve the ventilation and cooling effect of the granary, relevant scholars have optimized and upgraded the traditional ventilation system. For example, the Chinese patent with the patent application number: 201110152852.9 discloses a method and system for layered ventilation of a granary, by arranging a certain number of horizontal ventilation ducts on the ground of the granary and inside the grain pile to improve the cooling effect of the grain pile; the Chinese patent with the patent application number: 201510608233.4 discloses a granary ventilation system and method, by detecting the temperature and humidity inside the grain pile, the air temperature and humidity inside the warehouse and the atmospheric temperature and humidity outside the warehouse, and using a control module to adjust the opening time of the fan to regulate the grain pile temperature; the Chinese patent with the patent application number: 201610259887.5 discloses a transverse circulation ventilation system, which adjusts and reduces the grain pile temperature by arranging horizontal and vertical air ducts and using the principle of transverse ventilation; the Chinese patent with the patent application number: 202122988688.7 discloses a low-temperature grain storage granary system with a recyclable flowing water pipe laid at the bottom of the warehouse, which achieves the purpose of low-temperature grain storage through the overall heat insulation transformation of the granary and the transformation of the bottom refrigeration pipe system; the Chinese patent with the patent application number: 202221557643.2 discloses a new type of low-temperature grain storage granary, which promotes the flow of cold air around by adding a bottom annular air duct and a top blocking device.

[0004] However, there are still the following problems in the existing research on low-temperature grain storage ventilation systems: ① The technical bottleneck problem caused by the "cold core and hot skin" phenomenon of grain storage due to high summer temperatures has not been effectively solved; ② The existing ventilation systems have a single function and are only effective for a certain grain storage ventilation process requirement, with poor applicability and practicability; ③ It is difficult to achieve intelligent linkage targeted ventilation by autonomously sensing and controlling according to actual cooling requirements (such as bin wall cooling, grain surface temperature control, local grain pile cooling, whole bin cooling, etc.); ④ The functions of ventilation and refrigeration equipment are single, the integration is insufficient, and the overall equipment configuration cost is relatively high. Therefore, how to develop an applicable, practical, energy-saving and low-cost intelligent multi-functional ventilation system while ensuring that the grain temperature can meet the requirements of low-temperature grain storage during the storage period has important practical significance for promoting the development of green grain storage in China and ensuring national food security. Summary of the Invention

[0005] In order to solve the problems of the existing technology, the present invention provides an intelligent linkage multi-functional ventilation system for low-temperature grain storage and its ventilation method, which systematically solves the problem of economic losses of grain storage caused by reasons such as "local heating", "blind ventilation" and "cold core and hot skin" during storage, and realizes autonomous intelligent linkage targeted ventilation operation.

[0006] The present invention provides an intelligent linkage multi-functional ventilation system for low-temperature grain storage, including a ventilation pipe network, a main controller, and a number of refrigeration and air-conditioning units and a number of temperature and humidity sensors connected to the main controller. The refrigeration and air-conditioning units and temperature and humidity sensors are distributed in the ventilation pipe network. The ventilation pipe network includes an upper-layer annular ventilation duct, a lower-layer annular ventilation floor grille, and a bin bottom ventilation floor grille. Among them, the upper-layer annular ventilation duct is installed below the grain loading line on the side wall of the granary, and its cross-section is semi-circular; the lower-layer annular ventilation floor grille is vertically arranged along the corner of the bin body, and its cross-section is an isosceles triangle; the bin bottom ventilation floor grille is distributed on the bin bottom in a mountain shape. Each branch pipe of the ventilation pipe network can operate independently or cooperatively, effectively improving the ventilation effectiveness and the adaptability of the air-cooling capacity distribution.

[0007] There is a circular lower-layer annular ventilation floor grille along the bottom of the granary wall, and its cross-section is a sector with a central angle of 90°. Its two right-angled sides (the radii of the circle where the sector is located) are respectively fixed along the side wall and the ground of the granary; there is an annular upper-layer annular ventilation duct along the side wall of the granary, and its cross-section is semi-circular (with a central angle of 180°), and the diameter of the semi-circle is arranged along the side wall of the granary. The upper-layer annular ventilation duct is 0.5 - 1 m below the grain loading line (the intersection line of the highest grain loading surface in the granary and the side wall); the bin bottom ventilation floor grille arranged in a "mountain" shape is evenly laid on the granary ground, and the air inlet of each branch floor grille is connected to the lower-layer annular ventilation floor grille; there is a ventilation duct vertically arranged along the corner, and its cross-section is an isosceles triangle, and the two right-angled sides of the triangle are arranged along the side wall of the granary.

[0008] For further improvement, airtight dampers are provided in each ventilation duct of the ventilation pipe network, and the airtight dampers are regulated by the main controller; temperature sensors are evenly distributed in the granary, and the temperature sensors are connected to the main controller.

[0009] For further improvement, the upper-layer annular ventilation duct includes a first arc surface located above and a second arc surface located below, and openings are provided on the second arc surface. The upper-layer annular ventilation duct is located 0.5 m below the grain loading line on the side wall of the granary, and the radian of both the first arc surface and the second arc surface is 90°.

[0010] The opening rates of the second arc surface of the upper-layer annular ventilation duct and the lower-layer annular ventilation floor cage pipe network are both 30% - 35%; the materials of the upper-layer annular ventilation duct and the lower-layer annular ventilation floor cage pipe network are both preferably galvanized steel sheets (preferably steel sheets of model DX51D+Z), the thickness of the steel sheet is not less than 2 mm, and the diameter of the air duct is 0.45 - 0.5 m. Among them, the upper-layer annular ventilation duct and the lower-layer annular ventilation floor cage air duct are fixed to the side wall and the ground of the granary by conventional methods such as rivets and bolts.

[0011] For further improvement, the upper-layer annular ventilation duct is flexibly connected or disconnected from the return air duct of the refrigeration and air-conditioning unit to achieve negative pressure air suction or closing; the lower-layer annular ventilation floor cage and the bottom ventilation floor cage of the granary are connected to the air supply duct of the refrigeration and air-conditioning unit to achieve positive pressure air intake.

[0012] For further improvement, the lower-layer annular ventilation floor cage is vertically arranged along the four corners of the warehouse wall. Two adjacent air ducts are set as a group, and there are a total of two groups. One group is connected to the upper-layer annular ventilation duct, and the other group is connected to the bottom ventilation floor cage of the granary. The air outlet of each air duct in the lower-layer annular ventilation floor cage is 1.5 - 1.8 m above the grain loading line.

[0013] The present invention also provides a ventilation method for a smart and interconnected low-temperature grain storage multi-functional ventilation system. According to the environmental data collected by the sensors, it autonomously makes decisions and judgments on the ventilation temperature control mode, controls the opening and closing of the refrigeration and air-conditioning and the corresponding air ducts, and realizes targeted ventilation operations. The ventilation temperature control modes include a cooling wall type ventilation temperature control mode and a whole-warehouse natural ventilation temperature control mode.

[0014] Based on the temperature and humidity parameters inside and outside the silo and in the grain pile, and in accordance with the requirements of the low-temperature grain storage process (average grain temperature below 15°C, local maximum temperature not exceeding 20°C), the main controller makes an independent decision to determine the ventilation and temperature control mode, and then controls the opening and closing of the refrigeration air conditioner and the corresponding air ducts to achieve targeted ventilation operations. For example, under the influence of high temperature in summer (35 - 40°C), when the grain temperature near the silo wall (within 0.5 m from the silo wall) rises above 20°C, the "cold core and hot skin" phenomenon occurs. To eliminate the impact of external high temperature on the storage safety of the grain pile, the system independently determines the "cooling wall type ventilation and temperature control" mode, automatically controls the closing of the "mountain" shaped branch air ducts at the bottom of the silo, and opens the upper annular ventilation duct and the lower annular ventilation floor grating. Cold air is pressed into the grain pile through the air outlet duct of the refrigeration air conditioner and the lower annular ventilation floor grating, and the upper annular ventilation duct sucks the cold air from the lower layer through the grain layer in a directional manner with negative pressure and into the return air duct of the refrigeration air conditioner, forming a cooling wall type air wall isolation belt to block the influence of external high temperature on the grain pile temperature disturbance. For example, when the external temperature is below 10°C in autumn and winter, the system independently determines the "whole silo natural ventilation and temperature control" mode, automatically controls the closing of the upper annular ventilation duct, opens the branch air ducts at the bottom of the silo, and the refrigeration air conditioner is adjusted to the independent operation mode of the fan, using natural cold to cool the whole silo. Through intelligent linkage ventilation operations, the system ensures that the temperature inside the grain pile and the temperature near the wall surface are balanced throughout the storage cycle, with the average grain temperature below 15°C, achieving efficient, energy-saving, green, and intelligent low-temperature grain storage.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1. Higher energy efficiency. The system innovatively develops a "three-variable" (frequency conversion, variable air volume, variable air duct) ventilation control mode and researches and develops an intelligent linkage targeted ventilation system, effectively improving the refrigeration ventilation efficiency and temperature control ability;

[0017] 2. Stronger adaptability. The system can achieve multi-functional linkage operations of "one machine with four functions" (grain surface ventilation and temperature control, cooling wall ventilation and temperature control, local ventilation and temperature control, whole silo ventilation and temperature control), and can adapt to different scales of flat warehouses;

[0018] 3. Low transformation cost, simple and durable. The system makes great use of the existing ventilation floor grating system and supporting facilities, without the need for large-scale transformation, and only configuring a refrigeration unit can replace the integrated functions of traditional grain coolers, temperature control air conditioners, centrifugal fans and other equipment, saving the input costs of manpower and financial resources. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 It is the installation schematic diagram of the multi-functional ventilation system for low-temperature grain storage of the present invention;

[0021] Figure 2 It is the ventilation pipe network diagrams of the multi-functional ventilation system for low-temperature grain storage of the present invention;

[0022] Figure 3 It is the structure and cross-sectional schematic diagram after installation of the lower-layer annular ventilation floor cage of the multi-functional ventilation system for low-temperature grain storage of the present invention;

[0023] Figure 4 It is the structure and cross-sectional schematic diagram after installation of the upper-layer annular ventilation pipe of the multi-functional ventilation system for low-temperature grain storage of the present invention;

[0024] Figure 5 It is the layout diagram of the airtight air valves of each ventilation pipe of the multi-functional ventilation system for low-temperature grain storage of the present invention;

[0025] In the figure, 1 - granary roof; 2 - ventilation window; 3 - granary wall; 4 - main controller; 5 - granary door; 6 - air outlet pipe; 7 - refrigeration and air-conditioning unit; 8 - return air pipe; 9 - vertical ventilation pipe; 10 - floor ventilation floor cage at the bottom of the warehouse; 11 - lower-layer annular ventilation floor cage; 12 - upper-layer annular ventilation pipe; 12-1 - first arc surface; 12-2 - second arc surface; 13 - temperature-measuring cable; 14 - opening; 15 - granary floor; 16 - airtight air valve. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] This embodiment provides a multi-functional ventilation system for low-temperature grain storage with intelligent linkage, Figure 1 It is the installation schematic diagram of the multi-functional ventilation system provided by the embodiment of the present invention, Figure 2 It is the ventilation pipe network diagrams of the system provided by the embodiment of the present invention. As Figure 1 , Figure 2 shown, the granary adopted in this embodiment includes a granary roof 1, a ventilation window 2, a granary wall 3, a granary door 5 and an air outlet pipe 6.

[0028] The granary ventilation system provided in this embodiment is composed of a main controller 4, a refrigeration and air-conditioning unit 7, an outdoor air supply and return pipe 8, a vertical ventilation pipe 9, an in-warehouse ventilation pipe network, etc.; a lower-layer annular ventilation floor cage 11 is provided along the inner side of the granary wall 3 at the bottom of the granary (as Figure 3As shown in the figure, the cross-section of the lower-layer annular ventilation floor grille 11 is a quarter-circular sector, and its two right-angled sides (the radii of the circle where the sector is located) are respectively arranged along the side wall and the ground of the granary; an upper-layer annular ventilation duct 12 that is connected end to end in a circle is arranged along the side wall of the granary (as Figure 4 shown in the figure), its cross-section is semi-circular, and the diameter of the semi-circle is arranged along the side wall of the granary), and the upper-layer annular ventilation duct 12 is 0.5 m below the grain loading line (the intersection line of the highest grain loading surface in the granary and the bin wall); the arc surface of the semi-circle of the cross-section of the upper-layer annular ventilation duct 12 is composed of a first arc surface 12-1 and a second arc surface 12-2, and the second arc surface 12-2 is provided with uniform openings 14, and the first arc surface 12-1 is not provided with openings; in this embodiment, the circumferences of the upper-layer annular ventilation duct 12 and the lower-layer annular ventilation floor grille 11 are equal; 8 branch bin bottom ventilation floor grilles 10 are evenly distributed in a "mountain" shape on the granary ground 15, and the lengths of each branch ventilation floor grille are the same, and the air inlets communicate with the lower-layer annular ventilation floor grille 11; the vertical ventilation duct 9 is arranged along the inner side of the granary wall 3 at the four corners of the granary. Two adjacent ones on the short side of the granary are in a group, and a total of 2 groups are set. One group communicates with the lower-layer annular ventilation floor grille 11, and the other group communicates with the upper-layer annular ventilation duct 12;

[0029] The lower-layer annular ventilation floor grille 11 is connected to the air outlet of the refrigeration air-conditioning unit 7 through the external wall heat-insulating air outlet duct 6, and the upper-layer annular ventilation duct 12 is connected to the air inlet of the refrigeration air-conditioning unit 7 through the external wall heat-insulating return air duct 8, jointly forming a cold air inner circulation pipe network; the cold air of the return air duct 8 has two sources, and the incoming path is regulated by a closed air valve. One path can directly come from the cold quantity circulation in the bin, and the other path can directly come from the external natural cold air;

[0030] In this embodiment, the materials of the lower-layer "mountain"-shaped arranged ventilation floor grille 10, the lower-layer annular ventilation floor grille 11 and the upper-layer annular ventilation duct 12 are all galvanized steel sheets, the steel sheet model is DX51D+Z, and its thickness is 2 mm. The opening rates of the second arc surface 12-2 and the lower-layer annular ventilation floor grille network are both 30%, the opening diameter is 2.5 mm, and the diameter of each ventilation duct is 0.5 m.

[0031] In this embodiment, the outdoor pipes connecting the ventilation floor grille and the air inlets and outlets of the refrigeration air-conditioning unit 7 are made of stainless steel materials, and the outside of the pipes is completely wrapped with polyurethane heat-insulating materials with a thickness of 10 mm;

[0032] In this embodiment, a large high-rise flat warehouse (24 m×30 m) of a certain grain reserve depot in Nanjing is selected. The height of the granary is 10 m, the height of the grain pile in the bin is 7 m, and 3000 t of paddy is stored; 2 refrigeration air-conditioning units 7 are installed on the ground outside the side walls of the 2 long sides of the granary. The model is McQuay air conditioner MDB224WP, the power matching of a single air conditioner is 6.8 kW, the refrigeration capacity is 16 kW, and the air volume is 4000 m 3 / h, the minimum output air temperature can be set to 12°C, and it has two working modes (independent operation of the fan: natural ventilation; combined operation of the fan + compressor: refrigeration ventilation);

[0033] In this embodiment, the core processor of the main controller 4 is an enhanced single-chip microcomputer G80F922, the drive module is a ULN2003A drive chip, the wired communication module is EUART, the GSM / GPRS wireless module is MG323, the FlashROM of the main controller 4 is 512K bytes, and the memory capacity is 1GB;

[0034] In this embodiment, each branch air duct is provided with a sealed air valve 16. The sealed air valve 16 is a stainless steel electric air valve, purchased from Ningbo Wuyue Environmental Protection Technology Co., Ltd., and the model is BYMBD-250;

[0035] In this embodiment, the temperature measurement cable 13 is a temperature and humidity integrated armored temperature measurement cable (customized), purchased from Langfang Zhaosui Temperature Measurement Cable Co., Ltd., with a temperature measurement range of -55~125°C and a measurement accuracy of ±0.5°C; the distance between each temperature sensor on each temperature measurement cable is 1.5m, and the layout of the temperature measurement cable 13 in the granary is ( Figure 5 ): On the short side of the granary (in the 24m span direction), 6 groups of temperature measurement cables are arranged evenly in sequence, with an interval of 4.6m. On the long side of the granary (in the 30m span direction), 7 groups of temperature measurement cables are arranged evenly in sequence, with an interval of 4.8m. During the ventilation process, the grain condition temperature is detected every 3 hours;

[0036] The operation method of the above multi-functional ventilation system is as follows: First, according to the requirements of the low-temperature grain storage process (the average grain temperature is lower than 15°C, and the local maximum temperature does not exceed 20°C), the main controller makes an independent decision and judgment on the ventilation temperature control mode (grain surface ventilation temperature control, cooling wall ventilation temperature control, local ventilation temperature control, whole warehouse ventilation temperature control, etc.) by real-time monitoring the temperature and humidity parameters inside and outside the warehouse and in the grain pile, and then controls the opening and closing of the refrigeration air conditioner and the corresponding air ducts through the driver to achieve intelligent linkage targeted ventilation operations, ensuring that the temperature inside the grain pile and the temperature near the wall surface are balanced throughout the storage cycle, and the average grain temperature is below 15°C, achieving the purpose of efficient, energy-saving, green, and intelligent low-temperature grain storage.

[0037] The comparison of the temperature spatial distribution and energy consumption of the grain pile inside the warehouse during the one-year storage period between the multi-functional ventilation system in this embodiment and the traditional ventilation system (the system disclosed in the literature "Liu Qiang. Simulation and Optimization of the Mechanical Ventilation Process in Large Flat-roofed Granaries for Grain Storage [D]. Nanjing: Nanjing University of Finance and Economics, 2016.") is shown in Table 1 below:

[0038] Table 1 Temperature Spatial Distribution and Energy Consumption of the Grain Pile Inside the Warehouse During the One-year Storage Period Using the Multi-functional Ventilation System in the Embodiment and the Traditional Ventilation System (Time Span: October 23, 2021 - October 23, 2022)

[0039]

[0040] Note: The temperature data in the table was measured over the time span from October 23, 2021 to October 23, 2022, and the measurement location was a large flat warehouse (24m×30m) in a grain reserve depot in Nanjing. Among them, the basis for dividing the grain layers is as follows: the first layer (0.5m below the grain surface), the second layer (2m below the grain surface), the third layer (3.5m below the grain surface), the fourth layer (5m below the grain surface), and the fifth layer (6.5m below the grain surface). The temperature data in the above table is the highest, lowest temperature, average grain temperature and energy consumption of each grain layer within a storage year.

[0041] As can be seen from Table 1, during the entire one-year storage period of the traditional ventilation system, the average grain temperature of the whole warehouse can reach below 15°C (14.9°C), but the local highest grain temperature significantly exceeds 20°C (23.6 - 26.2°C), making it difficult to meet the requirements of the low-temperature grain storage process (i.e., the average grain temperature is below 15°C and the local highest grain temperature is below 20°C). Analysis shows that the high grain temperature mainly appears in the first layer and the grain near the warehouse wall (within 0.5m), indicating that the traditional ventilation system is difficult to effectively solve the problem of "cold core and hot skin" in summer high temperature, there are obvious ventilation dead zones, and it is difficult to ensure the uniformity of grain temperature, which will further affect the safety of grain storage. In contrast, during the entire one-year storage period of the multi-functional ventilation system of this embodiment, the average grain temperature of the whole warehouse is 13.8°C, and the local highest grain temperature is 16.3°C, fully meeting the requirements of the low-temperature grain storage process. The average grain temperature of the whole warehouse is 1.1°C lower than that of the traditional ventilation system. In addition, during the entire storage year, the energy consumption of the multi-functional ventilation system of this embodiment is 21309 kW·h, which is more than 25% lower than that of the traditional ventilation system (27068 kW·h), and the system construction cost is reduced by 20%. It can be seen that the multi-functional ventilation system of this embodiment has stronger energy-saving, efficient, and targeted ventilation and temperature control capabilities.

[0042] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments. In particular, for the equipment embodiments, the above description is only the preferred implementation manner of the present invention. Since it is basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments. The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. For any person skilled in the art in the technical field disclosed by the present invention, any changes or substitutions that can be easily thought of by those of ordinary skill in the technical field should be covered within the protection scope of the present invention without departing from the principle of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A multi-functional ventilation system for low-temperature grain storage with intelligent linkage and its ventilation method, including a ventilation pipe network, a main controller, several refrigeration and air-conditioning units, and temperature sensors. Characterized in that: The ventilation pipe network is composed of an upper-layer annular ventilation pipe, a ventilation floor cage at the bottom of the bin, and a vertical ventilation pipe along the corner of the bin wall. Among them, the upper-layer annular ventilation pipe is installed parallel to the ground below the grain loading line on the side wall of the granary; the ventilation floor cage at the bottom of the bin includes a lower-layer annular ventilation floor cage and a ventilation floor cage arranged in a "mountain" shape; the vertical ventilation pipe along the corner of the bin wall has an isosceles triangle cross-section, one group of which is connected to the upper-layer annular ventilation pipe, and the other group is connected to the lower-layer annular ventilation floor cage; the upper-layer annular ventilation pipe is located 0.5 m below the grain loading line on the side wall of the granary. The upper-layer annular ventilation pipe includes a first arc surface located above and a second arc surface located below. There are openings on the second arc surface, and the radian of both the first arc surface and the second arc surface is 90°.

2. The multi-functional ventilation system for low-temperature grain storage with intelligent linkage according to claim 1, Characterized in that: Sealed air valves are provided in each ventilation pipe of the ventilation pipe network, and the sealed air valves are regulated by the main controller; temperature sensors are evenly distributed in the granary, and the temperature sensors are connected to the main controller.

3. The multi-functional ventilation system for low-temperature grain storage with intelligent linkage according to claim 1, Characterized in that: The lower-layer annular ventilation floor cage in the ventilation floor cage at the bottom of the bin is arranged parallel to the bottom line of the bin wall, and the radian of the arc surface is 90° and is provided with full openings.

4. The multi-functional ventilation system for low-temperature grain storage with intelligent linkage according to claim 1, Characterized in that: There are 4 vertical ventilation pipes along the corner of the bin wall, with an isosceles triangle cross-section. Adjacent 2 air ducts are set as 1 group, and a total of 2 groups are divided. One group is connected to the upper-layer annular ventilation pipe, and the other group is connected to the ventilation floor cage at the bottom of the bin. The air outlet of each air duct is 1.5 - 1.8 m above the grain loading line.

5. The multi-functional ventilation system for low-temperature grain storage with intelligent linkage according to claim 1, Characterized in that: The upper-layer annular ventilation pipe is flexibly connected or disconnected from the return air pipe of the refrigeration and air-conditioning unit to achieve negative pressure air suction or closing; the ventilation floor cage at the bottom of the bin is connected to the air outlet pipe of the refrigeration and air-conditioning unit to achieve positive pressure air intake.

6. A ventilation method for a multi-functional ventilation system for low-temperature grain storage with intelligent linkage, using the multi-functional ventilation system for low-temperature grain storage with intelligent linkage according to any one of claims 1-5, Characterized in that: According to the environmental data collected by the sensor, autonomously make a decision to judge the ventilation temperature control mode, control the opening and closing of the refrigeration and air-conditioning and the corresponding air ducts, and realize targeted ventilation operation. The ventilation temperature control mode includes a cooling wall type ventilation temperature control, a grain surface temperature control, a local temperature control, and a whole-bin natural ventilation temperature control mode.

7. The ventilation method for a multi-functional ventilation system for low-temperature grain storage with intelligent linkage according to claim 6, Characterized in that: The cooling wall - type ventilation temperature control mode is enabled when the external air temperature is above 35°C or the grain temperature near the bin wall rises above 20°C. At this time, the ventilation ducts on the bottom of the bin are controlled to be closed, and the upper - layer annular ventilation ducts and the lower - layer annular ventilation ducts are opened. Cold air is pressed into the grain pile through the air - outlet ducts of the refrigeration and air - conditioning units and the lower - layer annular ventilation ducts. The upper - layer annular ventilation ducts suck the cold air attached to the wall and passing through the grain layer into the return - air ducts of the refrigeration and air - conditioning units through negative pressure, forming a cooling - wall - type air - wall isolation zone to block the influence of external high temperature on the grain - pile temperature disturbance.

8. The ventilation method of the intelligent - linkage low - temperature grain - storage multi - functional ventilation system according to claim 6, characterized in that: The whole - bin natural - ventilation temperature control mode is enabled when the external temperature is lower than 15°C. The upper - layer annular ventilation ducts are controlled to be closed, the air ducts of the ventilation ducts on the bottom of the bin are opened, and the refrigeration and air - conditioning units are adjusted to the independent - fan operation mode to cool the whole bin using natural cold.

Images