Granary dead-corner-free ventilation system based on positive and negative pressure cooperation

Abstract

The granary dead-corner-free ventilation system comprises a plurality of draught fans, a ventilation ground cage, a closed air valve, a frequency converter, an air distributor, a controller and the like, the draught fans are installed and arranged along the two sides outside a granary and have the positive and negative rotation function, namely, the positive pressure air supply function and the negative pressure air suction function, and the front ends of the draught fans are connected with the frequency converter; the rotating speed and the air volume can be adjusted as required; the rear end is connected with the ventilation ground cage; the ventilation ground cages are oppositely and crossly arranged in a through mode from the two sides along the bottom face of the granary, air supply outlets of the adjacent ground cages are different, the air supply direction can be adjusted and controlled by a controller to be matched with a fan to achieve the same mode and the opposite mode, and an electromagnetic air valve is arranged at the air supply outlet of each ventilation ground cage. The air supply modes (namely positive pressure air supply or one positive pressure and one negative pressure) of the adjacent ventilation ground cages are regulated and controlled, the flow direction of an air field in a grain pile is regulated and controlled according to the positive and negative pressure multi-air-duct collaborative operation principle, the two modes are alternately and circularly carried out, the problem of ventilation dead corners at the bottom of a granary is effectively solved, and the grain storage safety is guaranteed.

Description

Technical Field

[0001] This utility model relates to the technical field of ventilation systems for grain storage projects, specifically a grain storage ventilation system with no dead angles based on positive and negative pressure coordination. Background Technology

[0002] Ground-cage ventilation is the main method for controlling temperature, humidity, and water in tall, flat-roofed grain storage. However, the unique flow path characteristics of the airflow field inside the grain pile cause the problem of dead corners in the bottom ventilation of this type of ventilation system (i.e., triangular dead corner areas formed between adjacent ground-cage ventilation ducts). This can easily cause problems such as overheating, mold, condensation, and deterioration of the grain at the bottom of the storage, resulting in grain loss.

[0003] To address the aforementioned issues, current research focuses on three main areas: First, altering the cross-sectional shape of the ventilation duct, such as making it rectangular, triangular, trapezoidal, or trench-like, but this has limited effectiveness in eliminating ventilation dead zones at the bottom of the silo. Second, increasing ventilation pressure, velocity, volume, and duration can reduce dead zone areas to some extent, but it cannot fundamentally solve the problem and also leads to increased energy consumption and over-ventilation. Third, adding branch ducts and reducing the spacing between ventilation ducts can reduce and divide dead zone areas, but it cannot completely solve the problem and increases costs and the difficulty of entering and exiting the silo. Utility Model Content

[0004] To address the problems of existing technologies, this invention provides a grain storage ventilation system with no dead angles based on positive and negative pressure coordination. Taking into full account economic efficiency, simplicity, practicality, and high efficiency, the system optimizes and upgrades the duct network structure and utilizes the principle of positive and negative pressure multi-duct coordinated operation to regulate the airflow direction inside the grain pile. This effectively solves the problems of blind ventilation throughout the storage area and dead angles at the bottom of the storage area, which is of great practical significance for ensuring food security.

[0005] This utility model includes several ventilation cages distributed at the bottom of a grain silo. The ventilation cages are arranged in a crisscross pattern, running from both sides of the silo bottom, and are connected to axial flow fans. The axial flow fans are installed along both sides of the silo's exterior. Each axial flow fan connects to several ventilation cages with the same airflow direction via an air distributor. Each ventilation cage has an electromagnetic valve at its air inlet, and adjacent ventilation cages have different air outlets. The axial flow fans are connected to a controller via a frequency converter. The controller adjusts the forward or reverse rotation of the axial flow fans, thereby achieving positive pressure air supply and negative pressure air intake within the ventilation cages. The controller can adjust the opening and closing of specific cages and the air intake direction according to the actual grain storage ventilation requirements. By adjusting the air intake mode of adjacent ventilation cages, and utilizing the principle of multi-channel coordinated operation of positive and negative pressure, the airflow direction inside the grain pile is controlled. The two modes alternate, effectively solving the problems of blind ventilation throughout the silo and dead zones at the bottom.

[0006] Preferably, the fan is an axial flow fan with forward and reverse rotation function, which can meet the requirements of positive pressure air supply and negative pressure air suction.

[0007] Preferably, the opening ratio of the ventilation cage is 30% to 35%, preferably galvanized steel plate (such as steel plate of model DX51D+Z), and the thickness of the steel plate is not less than 2 mm; the ventilation cage is laid flat along the short side of the warehouse, and is evenly arranged in opposite directions, with different air inlets for adjacent ventilation cages.

[0008] Preferably, the airtight air valve (preferably a stainless steel electric airtight air valve) can be controlled by the controller to open and close the corresponding ventilation cage according to different grain storage process requirements.

[0009] Preferably, all the axial flow fans rotate forward to provide positive pressure air supply, or one side of the axial flow fans rotates forward to provide positive pressure air supply, and the other side fan rotates in reverse to provide negative pressure air intake, with the ventilation cages providing positive pressure air supply and the ventilation cages providing negative pressure air intake distributed alternately.

[0010] The working method of this utility model is as follows:

[0011] When ventilating the entire warehouse, firstly, both axial flow fans on both sides are in positive pressure air supply mode. The airflow passes through the grain pile and flows out from the upper layer, providing large-scale ventilation to the grain pile. After running for a period of time, one fan is switched to negative pressure suction mode, while the other fan remains in positive pressure air supply mode. This creates a small area of ​​airflow circulation field between adjacent air ducts at the bottom layer. The airflow flows out from the bottom air ducts, solving the ventilation dead zones at the bottom layer. The two modes are alternated and circulated to achieve uniform ventilation of the entire warehouse.

[0012] The beneficial effects of this utility model are as follows:

[0013] 1. Enhanced practicality. While largely preserving the original ventilation facilities, the principle of positive and negative pressure multi-channel coordinated operation is used to regulate the airflow direction inside the grain pile, and the alternating and circulating operation can effectively solve the problem of dead ventilation corners at the bottom of the silo.

[0014] 2. Higher energy efficiency. The controller can determine the ventilation purpose based on the grain condition and adjust the opening and closing of the corresponding cages. It has frequency conversion and targeted ventilation functions, avoiding increased energy consumption caused by blind ventilation and excessive ventilation.

[0015] 3. Enhanced adaptability. The system can adapt to warehouses of different sizes and types. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a structural diagram of the grain storage ventilation system with no dead angles according to this utility model;

[0018] Figure 2 This is a schematic diagram illustrating the working principle of the grain storage ventilation system with no dead angles according to this utility model.

[0019] In the diagram: 1-Grain warehouse, 1-1-Grain pile, 1-2-Grain surface, 1-3-Ventilation window, 2-Ventilation cage, 3-Axial flow fan, 4-Electromagnetic air valve, 5-Airflow field inside the grain pile under positive and negative pressure coordination mode, 6-Airflow field inside the grain pile under positive pressure mode, 7-Controller, 8-Frequency converter, 9-Air distributor. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0021] This utility model provides a technical solution for a grain warehouse ventilation system with no dead angles based on positive and negative pressure coordination. Figure 1 This is an overall structural diagram of the grain storage ventilation system with no dead angles according to this utility model. Figure 2 This is a schematic diagram illustrating the operating principle of the grain silo ventilation system with no dead angles, as described in this utility model. Figure 1 , Figure 2 As shown, the grain silo ventilation system provided in this embodiment consists of several axial flow fans 3, ventilation cages 2, electromagnetic valves 4, frequency converters 8, air distributors 9, controllers 7, etc.; the ventilation cages 2 are arranged in a through-type, opposite-facing pattern along the bottom of the grain silo from both sides. Each ventilation cage has an electromagnetic valve 4 at its air inlet; the axial flow fans 3 are installed along the outer walls of the silo, providing both positive pressure air supply and negative pressure air intake functions, with the front end connected to the frequency converter 8 and the rear end connected to the air distributor 9; in positive pressure mode, the fans supply positive pressure air, with the air supply direction opposite in adjacent ventilation cages, and the airflow in the grain silo flows from the ventilation cages through the grain pile to the ventilation windows, such as... Figure 2 In the positive pressure mode, the internal airflow field of the grain pile is shown in Figure 6. In the positive and negative pressure coordinated mode, the air supply direction in adjacent ventilation cages is the same, and the airflow in the grain silo flows from the positive pressure air supply cage to the negative pressure air suction cage at the bottom of the silo, forming several small-area circulating airflow fields, such as... Figure 2 The internal airflow field of the grain pile under the positive and negative pressure coordinated mode is 5. The ventilation operation without dead zones is completed by alternating between the two modes of positive pressure ventilation and positive and negative pressure coordinated ventilation.

[0022] In this embodiment, the opening ratio of the ventilation cage is 30% to 35%, preferably galvanized steel plate (such as steel plate with model DX51D+Z), the steel plate thickness is 2mm, and the diameter of each ventilation duct is 0.5m; the ventilation cage is laid flat along the short side of the warehouse and evenly arranged in opposite directions.

[0023] In this embodiment, the main controller 7 uses a G80F922 enhanced microcontroller as the core processor, a ULN2003A driver chip as the driver module, an EUART wired communication module, an MG323 GSM / GPRS wireless module, a 512KB FlashROM for the main processor 4, and a 1GB memory capacity.

[0024] In this embodiment, each branch air duct is equipped with an electromagnetic air valve 4. The airtight air valve 4 is a stainless steel electric air valve, purchased from Ningbo Wuyue Environmental Protection Technology Co., Ltd., model BYMBD-250.

[0025] In this embodiment, the axial flow fan is selected as a bidirectional forward and reverse axial flow fan with a single unit air volume of 17845 m³ / h, manufactured by Anhui Huazhong Machinery Co., Ltd., model T5-72-2.2kW.

[0026] In this embodiment, a tall, flat warehouse (24m × 20m) of a grain reserve in Nanjing was selected. The grain pile inside the warehouse is 7m high and stores 2000t of rice. The top of the grain warehouse 1 has ventilation windows 1-3. Figure 1 In the process, the grain is formed into grain pile 1-1 and grain surface 1-2. Upon entering the warehouse, the rice moisture content is 14.5%, and the fatty acid value is 15.5 (KOH) / (mg / 100g), and the following settings are provided: Figure 2 The measurement points A (non-ventilation dead zone area) and B (ventilation dead zone area) are shown. Table 1 compares the grain storage conditions of the ventilation system in this embodiment with those of a traditional ventilation system (the system disclosed in the literature "Liu Qiang. Simulation and Optimization of Mechanical Ventilation Process in High-Rise Flat Grain Storage [D]. Nanjing: Nanjing University of Finance and Economics, 2016").

[0027] Table 1 Comparison of grain storage conditions between the positive and negative pressure coordinated ventilation system and the traditional ventilation system in this embodiment (one-year storage period)

[0028]

[0029] As shown in Table 1, traditional ventilation systems exhibit significant ventilation dead zones at the bottom of the grain pile, namely the triangular areas between adjacent air ducts. This leads to uneven temperature distribution in the bottom area, with a temperature difference of 8.2℃ between monitoring points A and B. Furthermore, due to localized overheating and poor ventilation, condensation and mold growth occur, and the fatty acid value of the rice rises rapidly (5.9 [(KOH / dry basis) / (mg / 100g)]), accelerating the deterioration of rice quality. In contrast, the ventilation system in this embodiment employs a positive and negative pressure coordinated ventilation design, effectively eliminating ventilation dead zones at the bottom and achieving uniform ventilation. The temperature difference between monitoring points A and B is only 0.2℃, showing no significant difference. No condensation or mold growth occurs during storage, and the fatty acid value of the rice rises slowly (2.1 [(KOH / dry basis) / (mg / 100g)]). This demonstrates significant practical value in ensuring grain storage safety, reducing storage losses, and minimizing quality deterioration.

[0030] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model, without departing from the principle of this utility model, should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A positive and negative pressure cooperation-based warehouse dead angle-free ventilation system, characterized in that: It comprises several ventilation ground cages distributed at the bottom of the granary, which are arranged in opposite directions through the bottom surface from both sides, connected with axial flow fans, one axial flow fan is connected with several ventilation ground cages with the same air direction through an air distributor, an electromagnetic air valve is arranged at the air inlet of each ventilation ground cage, and the air inlets of adjacent ventilation ground cages are different; the axial flow fans are connected with a controller through a frequency converter, the controller controls the forward rotation or reverse rotation of the axial flow fans on both sides, realizes the positive pressure air supply or negative pressure air suction of the ventilation ground cage, controls the air supply mode of adjacent ground cages, controls the flow direction of the air field inside the grain pile by the principle of positive and negative pressure multi-air duct collaborative operation, and the two modes are alternately and circularly performed to eliminate the ventilation dead angle at the bottom of the granary.

2. The positive and negative pressure cooperation based warehouse dead angle free ventilation system according to claim 1, characterized in that: The ventilation ground cages are arranged in opposite directions through the short side of the granary house, uniformly arranged in opposite directions, and the air inlets of adjacent two ventilation ground cages are different.

3. The positive and negative pressure cooperation based warehouse dead angle free ventilation system according to claim 1, characterized in that: The ventilation ground cages are all provided with electromagnetic air valves, which are controlled by the controller to open and close and control the air inlet direction according to the actual storage grain ventilation working condition requirement.

4. The positive and negative pressure cooperation based warehouse dead angle free ventilation system according to claim 1, characterized in that: The axial flow fans are arranged along the two sides outside the granary, have the functions of forward rotation positive pressure air supply and reverse rotation negative pressure air suction, and the rotation directions of the fans on both sides are cooperatively controlled by the controller.

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