Material dryer and drying process thereof

Abstract

The invention belongs to the technical field of drying equipment, and particularly relates to a material drying machine and a drying process thereof. The material drying machine comprises a box body, a multi-layer mesh belt machine and an air supply pipe; the box body is provided with a mesh belt chamber and an air duct chamber, and the multi-layer mesh belt machine is arranged in the mesh belt chamber; the air duct chamber is divided into independent air cavities by a plurality of partition plates, a hot air conveying device is arranged in each air cavity, and preheating air inducing devices are arranged in several air cavities; a dehumidifying device communicated with the air cavity is arranged on the box body; an air inlet and an air outlet which are communicated with the air cavity are respectively formed in two side walls of the mesh belt chamber; the multi-layer mesh belt machine comprises three layers of mesh belts which are respectively a first layer of mesh belt, a second layer of mesh belt and a third layer of mesh belt from top to bottom; and the preheating air inducing device is positioned between the first-layer mesh belt and the second-layer mesh belt. By arranging the preheating air inducing device with the heat recovery device, heat in damp and hot waste gas can be actively absorbed and stored in the dehumidification stage.

Description

Technical Field

[0001] This invention belongs to the field of drying equipment technology, specifically relating to a material dryer and its drying process. Background Technology

[0002] Belt dryers (also known as mesh belt dryers) are a type of continuous drying equipment widely used in the pharmaceutical, food, chemical, and agricultural product processing industries. They are particularly suitable for dehumidifying and drying lumpy, flake, strip, and granular materials. Their working principle typically involves laying the material on a multi-layer mesh belt, with hot air penetrating the material layers to achieve heat and moisture exchange. As industry demands for higher material drying quality, ensuring uniform temperature and humidity during the drying process and improving thermal efficiency have become key areas for equipment upgrades.

[0003] In existing technologies, such as the internal circulation system of a belt dryer disclosed in patent CN207379239U, a three-sided surrounding air duct is set between the chamber and the mesh belt chamber, and inclined baffles are used to guide the airflow through each layer of the mesh belt. The aim is to solve the problem of weakened air pressure and turbulent airflow when hot air penetrates multiple layers of mesh belts. However, in this solution, the hot air is still uniformly heated from the bottom and then penetrates all layers upwards. Although the airflow is guided in layers by baffles, the temperature and humidity between each layer still affect each other. As a result, the material in the upper layer (wet material) often comes into contact with air that has been preheated by the lower layer and has higher humidity. This leads to insufficient drying driving force and easily causes uneven drying and damage to the material's appearance.

[0004] To address the issues of insufficient hot air circulation and energy waste, patent CN212431658U discloses a high-efficiency, energy-saving belt dryer. This design divides the drying chamber into two enclosed primary and final drying chambers, and introduces the hot air exhausted from the final drying chamber into the primary drying chamber for secondary use, thus achieving a degree of internal hot air circulation. However, its structure is relatively complex, and the reused hot air still needs to be reheated. Furthermore, the waste heat from the large amount of high-humidity, high-temperature air discharged during the dehumidification stage is not effectively recovered, resulting in this heat being directly released into the atmosphere and causing energy waste.

[0005] Another improvement approach is found in patent CN118089375A, which provides a heat equalization device for a mesh belt dryer. This device uses multiple independent heat equalization plates inserted into the air box and airflow control valves to individually adjust the hot air flow and temperature for each layer. This method improves the problem of overheating in the lower layers and underheating in the upper layers to some extent. However, its heat generation units (hot air furnace and circulating fan) are still a centralized design, requiring the hot air to be distributed to each layer through long pipelines, which poses risks of heat loss and uneven pressure along the way. Furthermore, the structure of the heat equalization plates dictates that the hot air is ejected in one direction, lacking planning for the overall circulation path of the airflow within the box 1, resulting in limited cascade utilization of thermal energy.

[0006] In summary, existing technologies generally suffer from the following shortcomings: the temperature and humidity distribution in multi-layer drying equipment is difficult to control precisely, resulting in uneven drying effects across layers; humid and hot exhaust gases are directly emitted, and the large amount of latent and sensible heat they contain is not recovered and utilized, leading to high energy consumption; cleaning and maintenance of the equipment's interior are not convenient, especially regarding the accumulation of fine materials. Therefore, there is an urgent need for a new type of dryer that can achieve independent temperature and humidity control for each layer, effectively recover waste heat, and facilitate maintenance. Summary of the Invention

[0007] To address the aforementioned technical problems, one objective of this invention is to provide a material dryer that solves the problems of high drying energy consumption, low hot air circulation efficiency, and inflexibility in adapting to different drying stages due to the lack of active recovery and utilization of exhaust heat. Another objective of this invention is to provide a drying process.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A material dryer includes a housing, a multi-layer mesh belt conveyor, and an air supply duct. The housing has a mesh belt chamber and an air duct chamber, with the multi-layer mesh belt conveyor housed within the mesh belt chamber. The air duct chamber is divided into independent air chambers by several partitions, each air chamber being equipped with a hot air conveying device, and several air chambers being equipped with preheating and induced draft devices. The housing is equipped with a dehumidification device communicating with the air chambers. Air inlets and outlets communicating with the air chambers are respectively provided on the two side walls of the mesh belt chamber. The multi-layer mesh belt conveyor includes three mesh belts, from top to bottom: a first mesh belt, a second mesh belt, and a third mesh belt. The preheating and induced draft device is located between the first and second mesh belts. The preheating and exhaust fan device includes a preheating hood, a heat recovery device, and a first exhaust fan; the outer shell of the first exhaust fan and the preheating hood are both fixedly connected to the housing; the air inlet of the first exhaust fan is connected to the air supply pipe through the preheating hood, and the air outlet of the exhaust fan is connected to the air chamber; the heat recovery device is installed inside the preheating hood; there is a gap between the preheating hood and the side wall of the air chamber to form a flow channel; the upper and lower ends of the preheating hood are provided with openings and sealing mechanisms. During dehumidification, the openings at both ends are opened by the sealing mechanism, the flow channel is sealed, the humid air passes through the preheating hood and is discharged through the dehumidification device; the heat recovery device inside the preheating hood absorbs the heat of the humid air. During drying, the openings at both ends are closed by the sealing mechanism, and the flow channel is in a connected state. After the external air absorbs heat from the heat recovery device and is heated, it is discharged by the first induced draft fan. The hot air is then heated by the hot air conveying device to form hot air and is conveyed. The hot air passes through the air inlet, air outlet and flow channel in sequence and then passes through the hot air conveying device to form a circulation. When it is necessary to increase the air speed, the upper opening is opened by the sealing mechanism, the flow channel is in a blocked state, and the hot air discharged from the air outlet is accelerated by the first induced draft fan.

[0009] The remaining air chambers are equipped with backup heating devices; the backup heating devices are located between the second and third mesh belts; the backup heating devices include a heating cover, a heating device, and a second exhaust fan; the outer shell of the second exhaust fan and the heating cover are both fixedly connected to the housing, the air inlet of the second exhaust fan is connected to the air supply pipe through the heating cover, and the air outlet of the second exhaust fan is connected to the air chamber; the heating device is installed inside the heating cover; there is a gap between the heating cover and the side wall of the air chamber; During drying, if the hot air conveying device in the corresponding air chamber is damaged or the temperature is insufficient, the outside air is heated by the supplementary heating device; the heat is supplemented by the backup supplementary heating device or temporarily replaced by the damaged hot air conveying device.

[0010] The heat recovery device consists of several heat exchange tubes, which are filled with heat-conducting oil.

[0011] The sealing device includes an upper sealing plate and a lower sealing plate, which are slidably connected to the upper and lower ends of the control cover, respectively. The upper sealing plate and the lower sealing plate are respectively connected to a telescopic mechanism, which controls the movement of the upper sealing plate and the lower sealing plate.

[0012] The upper part of the control cover is provided with an open section, and the first opening at the upper end is located at the open section.

[0013] Each layer of mesh belt has a partition plate in the middle, which is inclined and fixedly connected to the box body; the partition plate of the first layer of mesh belt is equipped with a collection and cleaning mechanism.

[0014] The collection and cleaning mechanism includes a collection trough and an exhaust pipe. The collection trough is fixedly connected to a partition plate and located at the lower part of the partition plate. The partition plate has an opening that communicates with the collection trough. One end of the exhaust pipe is connected to the collection trough.

[0015] Each layer of the conveyor belt has an adjustable baffle at its corresponding air inlet, and the adjustable baffles are fixedly connected to each other by vertical plates; a drive mechanism is fixedly connected to the housing, and the drive mechanism is connected to the uppermost adjustable baffle; the air inlet can be adjusted by the adjustable baffle, and a temporary storage slot is formed with the partition plate.

[0016] The drying process includes the following steps: S1, Dehumidification Stage: The control sealing mechanism opens the openings at both ends of the preheating hood and seals the flow channel. The humid air passes through the inside of the preheating hood and is discharged through the dehumidification device. At the same time, the heat recovery device inside the preheating hood absorbs the heat of the humid air. S2, Drying stage: The control sealing mechanism closes the openings at both ends of the preheating hood and keeps the flow channel connected; after the outside air enters the preheating hood, it absorbs the heat from the heat recovery device and is heated up. It is then sent into the air chamber by the first induced draft fan, and finally heated by the hot air conveying device to form hot air and conveyed to the mesh belt chamber; after the hot air dries the material in the mesh belt chamber, it passes through the air outlet, flow channel and hot air conveying device in sequence to form a circulation. S3, Acceleration Stage: When it is necessary to increase the wind speed, the control sealing mechanism opens the opening at the top of the preheating hood and seals the flow channel, so that the hot air discharged from the air outlet is accelerated by the first induced draft fan.

[0017] It also includes a backup heating step: When the hot air delivery device in the corresponding air cavity is damaged or the temperature is insufficient, the backup heating device is activated; outside air enters the heating cover, is heated by the heating device, and is then sent into the corresponding air cavity by the second induced draft fan to supplement the heat or temporarily replace the damaged hot air delivery device.

[0018] Compared with the prior art, the beneficial effects of this invention are: By incorporating a preheating induced draft device with heat recovery, this invention can actively absorb and store heat from the humid waste gas during the dehumidification stage. In the subsequent drying stage, this stored heat is used to preheat the fresh air entering the system, achieving cascaded recovery and reuse of waste heat. This significantly reduces the heating load on the hot air conveying device, thereby effectively saving energy consumption and lowering operating costs.

[0019] By dividing the air duct chamber into multiple independent air chambers and equipping each chamber with an independent hot air delivery device, precise control of the drying environment of each layer of the conveyor belt is achieved. In particular, the inclusion of a preheating induced draft device and a backup supplementary heating device allows the equipment to flexibly switch operating modes according to different drying stages (such as normal drying and accelerated purging) and operating conditions (such as high humidity or heat source failure). For example, during the accelerated drying stage, guiding hot air directly into the induced draft fan can significantly increase the local wind speed, meeting the process requirements of rapid dehydration or surface purging, and ensuring the uniformity of material drying and the quality of the finished product.

[0020] The backup heating device provides dual protection for the stable operation of the equipment. When the hot air conveying device in a certain air chamber malfunctions or the heat is insufficient due to high material moisture, the backup heating device can be quickly activated to supplement the heat or even temporarily replace the faulty equipment, ensuring the temperature in the drying chamber is stable. This avoids production interruptions and material losses caused by equipment shutdown or insufficient heat source, greatly improving the reliability of the equipment and its adaptability to complex working conditions.

[0021] By installing a collection and cleaning mechanism at the bottom of the partition plate on the first layer of the conveyor belt, a large amount of particulate matter falling from the mesh belt holes can be collected and discharged, avoiding the accumulation and mold growth of materials inside the machine and reducing the frequency and difficulty of manual cleaning. At the same time, the temporary storage tank structure composed of adjusting baffles and partition plates also provides convenience for the temporary storage and centralized cleaning of small amounts of particulate matter, ensuring the cleanliness and hygiene of the equipment interior. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the present invention; Figure 2 This is a partial structural schematic diagram of the present invention; Figure 3 yes Figure 2 Axonometric view of the structure shown; Figure 4 yes Figure 3 A magnified view of a section at point C; Figure 5 yes Figure 2 A cross-sectional view of the structure shown; Figure 6 This is a schematic diagram of the preheating and induced draft device of the present invention; Figure 7 yes Figure 2 Cross-sectional view along the AA direction; Figure 8 yes Figure 7 A magnified view of a section at point D; Figure 9 yes Figure 7 A magnified view of a section at point E in the middle; Figure 10 yes Figure 7 A magnified view of a section at point F in the middle; Figure 11 yes Figure 2 Sectional axonometric view along the BB direction; Wherein: 1 is the housing, 100 is the mesh belt chamber, 101 is the air cavity, 102 is the air inlet, 103 is the air outlet, 104 is the flow channel, 2 is the multi-layer mesh belt conveyor, 20 is the first layer mesh belt, 21 is the second layer mesh belt, 22 is the third layer mesh belt, 3 is the air supply pipe, 4 is the partition, 5 is the hot air conveying device, 6 is the dehumidification device, 7 is the preheating and induced draft device, 70 is the preheating hood, 700 is the opening, 71 is the heat recovery device, 72 is... The first induced draft fan, 8 is the sealing mechanism, 80 is the upper sealing plate, 81 is the lower sealing plate, 82 is the telescopic mechanism, 83 is the open section, 9 is the backup heating device, 90 is the heating cover, 91 is the heating device, 92 is the second induced draft fan, 10 is the maintenance door, 11 is the collection and cleaning mechanism, 110 is the collection trough, 111 is the exhaust pipe, 12 is the adjusting baffle, 13 is the drive mechanism, 14 is the temporary storage trough, 15 is the partition plate, and 16 is the vertical plate. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1

[0024] like Figures 1 to 11 As shown, a material dryer includes a housing 1, a multi-layer mesh belt conveyor, and an air supply pipe 3. The housing 1 has a mesh belt chamber 100 and an air duct chamber, with the multi-layer mesh belt conveyor installed inside the mesh belt chamber 100. The air duct chamber is divided into independent air chambers 101 by several partitions 4. Each air chamber 101 is equipped with a hot air conveying device 5. The function of the hot air conveying device 5 is to finally heat the air and then convey the heated air into the air chamber 101 to form a circulation. The hot air conveying device 5 can adopt the structure of existing technology, which mainly includes a circulating fan and a heater. After being heated by the heater, the air is conveyed by the circulating fan.

[0025] The housing 1 is equipped with a dehumidification device 6 that communicates with the air chamber 101. The dehumidification device 6 is mainly a dehumidification fan, which is connected to each air chamber 101 through pipelines and is equipped with valves to control the on / off state. When the humidity inside the housing 1 is too high, the valves and the dehumidification fan are opened to expel the humid air, thereby reducing the humidity inside the housing 1.

[0026] The multi-layer mesh belt machine includes three mesh belts, which are, from top to bottom, the first mesh belt 20, the second mesh belt 21 and the third mesh belt 22; the two side walls of the mesh belt chamber 100 are respectively provided with air inlets 102 and air outlets 103 that communicate with the air chamber 101; each mesh belt has an air inlet 102 and an air outlet 103.

[0027] The temperature and humidity distribution in a multi-layer mesh belt dryer typically follows a change from the bottom layer (high temperature, low humidity) to the top layer (medium to low temperature, high humidity). This is determined by the circulation pattern of hot air entering from the bottom layer, penetrating the material layer by layer upwards, and finally exiting from the top layer. Taking the three-layer mesh belt in this dryer as an example, the temperature and humidity of the hot air at point 20 on the first layer mesh belt are low.

[0028] A preheating air duct 7 is provided in part of the air cavity 101, located between the first mesh belt 20 and the second mesh belt 21. The main function of the preheating air duct 7 is to absorb the heat from the air passing through the third mesh belt 22 (which has a relatively low humidity content and a high temperature) during the dehumidification stage for heat storage; secondly, it can also increase the air flow rate in the air cavity 101 as needed.

[0029] Specifically, the preheating and exhaust fan 7 includes a preheating hood 70, a heat recovery device 71, and a first exhaust fan 72. The outer casing of the first exhaust fan 72 and the preheating hood 70 are both fixedly connected to the housing 1. The air inlet 102 of each first exhaust fan 72 is connected to the air supply pipe 3 through the preheating hood 70 and is equipped with a valve (which can be turned on or off as needed). The exhaust port of the exhaust fan is connected to the air chamber 101, which can introduce external air into the air chamber 101 after passing through the preheating hood 70 to replenish the air supply.

[0030] The heat recovery device 71 is installed inside the preheating hood 70; there is a gap between the preheating hood 70 and the side wall of the air cavity 101 to form a flow channel 104; the upper and lower ends of the preheating hood 70 are provided with openings 700 and sealing mechanisms 8.

[0031] The dryer operates by first drying, and then dehumidifying when necessary during the drying process; after dehumidification, the drying operation continues. Therefore, during the initial drying phase, the heat recovery device 71 does not actually absorb heat from the humid air; it only absorbs heat after dehumidification. Thus, during the initial drying phase, the preheating fan device 7 mainly serves to induce airflow, and its preheating capacity is limited. Therefore, "drying during" in the following description refers to the drying process after dehumidification.

[0032] During dehumidification, the openings 700 at both ends are opened by the sealing mechanism 8, and the flow channel 104 is sealed. The humid air discharged through the third mesh belt 22 passes through the preheating hood 70, where the heat recovery device 71 absorbs the heat from the humid air before it is discharged through the dehumidification device 6. The function of sealing the flow channel 104 is to ensure that the humid air can only flow upwards through the preheating hood 70.

[0033] During subsequent drying, the openings 700 at both ends are closed by the sealing mechanism 8, allowing air inside the chamber 1 to circulate through the flow channel 104. External air is introduced by the first fan, heated by the heat recovery device 71, and then discharged by the first induced draft fan 72. Finally, it is heated by the hot air conveying device 5 to form hot air, which is then conveyed. The hot air passes sequentially through the air inlet 102, air outlet 103, and flow channel 104 before circulating through the hot air conveying device 5.

[0034] When an increase in airflow is required, the upper opening 700 is opened via the sealing mechanism 8, and the flow channel 104 is sealed; the valve connected to the air supply pipe 3 is closed, meaning no external air is introduced. The internal air of the housing 1 enters the preheating hood 70 through the upper opening 700, and is then accelerated by the first induced draft fan 72 before being discharged into the housing 1.

[0035] Furthermore, in addition to the air cavity 101 equipped with the preheating air duct device 7, the other air cavities 101 are equipped with backup heating devices 9; the backup heating devices 9 are located between the second mesh belt 21 and the third mesh belt 22. In terms of layout, the backup heating devices 9 and the preheating air duct device 7 are arranged alternately and staggeredly.

[0036] The backup heating device 9 includes a heating cover 90, a heating device 91, and a second induced draft fan 92. The outer shell of the second induced draft fan 92 and the heating cover 90 are both fixedly connected to the housing 1. The air inlet 102 of the second induced draft fan 92 is connected to the air supply pipe 3 through the heating cover 90. A control valve is provided at the connection point, which can be opened and closed as needed.

[0037] The exhaust port of the second induced draft fan 92 is connected to the corresponding air cavity 101; the heat replenishment device 91 is installed inside the heat replenishment cover 90; there is a gap between the heat replenishment cover 90 and the side wall of the air cavity 101, through which the hot air in the air cavity 101 can circulate. The heat replenishment device 91 is a heating device, which can be an electric heating device.

[0038] During drying, if the hot air conveying device 5 in the corresponding air chamber 101 is damaged or the temperature is insufficient, the corresponding control valve and the second induced draft fan 92 are opened, and the outside air is heated by the supplementary heating device 91. The heat is supplemented by the backup supplementary heating device 9 or temporarily replaced by the damaged hot air conveying device 5.

[0039] Furthermore, the heat recovery device 71 consists of several heat exchange tubes filled with heat transfer oil. During the dehumidification process, heat is absorbed and stored through the heat transfer oil; when outside air passes through, it absorbs heat and rises in temperature through the heat exchange tubes (heat transfer oil).

[0040] Furthermore, the sealing device includes an upper sealing plate 80 and a lower sealing plate 81, which are slidably connected to the upper and lower ends of the control cover, respectively. The upper sealing plate 80 and the lower sealing plate 81 are respectively connected to a telescopic mechanism 82, which controls the movement of the corresponding upper sealing plate 80 and lower sealing plate 81 to realize the opening and closing of the openings 700 at the upper and lower ends.

[0041] The telescopic mechanism 82 specifically adopts a telescopic cylinder; taking the telescopic cylinder connected to the upper sealing plate 80 as an example, the cylinder body of the telescopic cylinder is fixedly connected to the housing 1, and the piston rod of the telescopic cylinder is connected to the upper sealing plate 80; the connection method of the lower sealing plate 81 is the same.

[0042] Furthermore, the upper part of the control cover is provided with an open section 83, and the first opening 700 at the upper end is located at the open section 83; this structural arrangement can increase the amount of air entering the air cavity 101 when it is necessary to increase the wind speed.

[0043] Furthermore, each layer of the mesh belt is provided with a partition plate 15 in the middle. The partition plate 15 is inclined and fixedly connected to the box body 1. The partition plate 15 mainly serves to guide the flow.

[0044] Hot air conveyed by the hot air conveying device 5 enters the corresponding partition plate 15 through the air inlet 102 in sequence. Under the action of the partition plate 15, the hot air passes through the upper part of each layer of mesh belt and is discharged through the air outlet 103. Specifically, the air inlet 102 is located at the lower part of the partition plate 15, and the air outlet 103 is located at the higher part of the partition plate 15.

[0045] Taking the third layer mesh belt 22 as an example, hot air enters through the air outlet 103 along the lower part of the partition plate 15, passes through the upper part of the third layer mesh belt 22, and then returns to the air cavity 101 through the air outlet 103. Specifically, the air cavity 101 is U-shaped.

[0046] In this dryer, the first mesh belt 20 receives the material, which is then transferred to the second and third mesh belts 22 and then to the outside. Since the first mesh belt 20 receives the material, most of the particles smaller than the mesh belt holes will fall onto the partition plate 15 of the first mesh belt 20. Therefore, a collection and cleaning mechanism 11 is provided at the partition plate 15 of the first mesh belt 20 to clean the collected particles out of the chamber 1.

[0047] Furthermore, the collection and cleaning mechanism 11 includes a collection tank 110 and an exhaust pipe 111. The collection tank 110 is fixedly connected to the partition plate 15 and located at the lower part of the partition plate 15. After falling, particles will slide down the partition plate 15 to the lower part and enter the collection tank 110 through the openings on the partition plate 15. One end of the exhaust pipe 111 is connected to the collection tank 110, and the other end of the exhaust pipe 111 is connected to an exhaust fan. By starting the exhaust fan, the particles in the collection tank 110 are sucked out, achieving the purpose of cleaning.

[0048] Of course, collection and cleaning devices can also be installed at the partition plates 15 of the second and third mesh belts 21 and 22; however, the particles mainly fall on the partition plates 15 of the first mesh belt 20; therefore, the installation at both can be omitted.

[0049] Furthermore, each layer of mesh belt is equipped with an adjusting baffle 12 at the corresponding air inlet 102, and the adjusting baffles 12 are fixedly connected to each other by a vertical plate 16; a drive mechanism 13 is fixedly connected to the housing 1, and the drive mechanism 13 is connected to the uppermost adjusting baffle 12; the size of the air inlet 102 can be changed by adjusting the baffle 12, so as to achieve the purpose of adjustment.

[0050] The drive mechanism 13 specifically adopts a telescopic cylinder. The cylinder body of the telescopic cylinder is fixedly connected to the housing 1, and the piston rod of the telescopic cylinder is fixedly connected to the uppermost adjusting baffle 12. A corresponding horizontal plate is fixedly connected to the uppermost adjusting baffle 12 for fixed connection with the piston rod.

[0051] When the air inlet 102 needs to be enlarged, the piston rod of the telescopic cylinder extends, causing each adjusting baffle 12 to move downward, reducing the obstruction of the air inlet 102; when the air inlet 102 needs to be reduced, the piston rod of the telescopic cylinder retracts, causing each adjusting baffle 12 to move upward, increasing the obstruction of the air inlet 102.

[0052] In addition to adjusting the size of the air inlet 102, the aforementioned adjusting baffle 12 also prevents particles dripping onto the partition plate 15 from sliding into the air cavity 101; that is, the adjusting baffle and the partition plate 15 form a temporary storage groove 14 (mainly for the second layer mesh belt 21 and the third layer mesh belt 22), which can temporarily store particles. An inspection door 10 is provided on the corresponding side of the housing 1, allowing access by opening the inspection door 10 (e.g., ...). Figure 3 and Figure 4 (As shown), clean the particulate matter in the temporary storage tank 14. Example 2

[0053] This embodiment provides a drying process based on Embodiment 1, including the following steps: S1. Dehumidification Stage: When the humidity inside the mesh belt chamber 100 is too high and it is necessary to discharge the high-humidity exhaust gas outside the machine, the dehumidification stage is executed. The sealing mechanism 8 is activated, simultaneously opening the openings 700 at both the upper and lower ends of the preheating hood 70. In this state, the flow channel 104 between the preheating hood 70 and the side wall of the air cavity 101 is blocked, and the machine is in a sealed state.

[0054] The hot and humid air inside the conveyor belt chamber 100, under the negative pressure generated by the dehumidification device 6, is discharged from the air outlet 103. Since the flow channel 104 is blocked, it can only enter the preheating hood 70 through the lower opening 700, pass through the preheating hood 70, and exit from the upper opening 700, ultimately being discharged outdoors through the dehumidification device 6 on the housing 1. During the flow of the hot and humid air through the preheating hood 70, the heat it carries is absorbed and stored by the heat recovery device 71 installed inside the preheating hood 70. In this way, in the subsequent drying stage, this stored heat can be used to preheat newly entering external air, thereby achieving waste heat recovery and reducing energy consumption.

[0055] S2, Drying Stage: When the equipment is in normal drying operation mode, the drying stage is executed. The drive sealing mechanism 8 is activated to close the openings 700 at both ends of the preheating hood 70. In this state, the flow channel 104 between the preheating hood 70 and the side wall of the air chamber 101 is in a connected state.

[0056] External air enters the preheating hood 70 under negative pressure and flows through the heat recovery device 71 inside the preheating hood 70. Since the heat recovery device 71 has stored heat during the previous dehumidification process, the external air is preheated as it passes through. The preheated air is then drawn in through the air inlet 102 of the first induced draft fan 72 and sent into the corresponding air chamber 101 through the air outlet. Inside the air chamber 101, the hot air conveying device 5 performs final heating on the air to bring it to the temperature required for drying, and then sends it into the mesh belt chamber 100 through the air inlet 102 on the side wall of the mesh belt chamber 100.

[0057] Hot air dries the material on the multi-layer mesh belt. After heat and moisture exchange, the air temperature decreases and the humidity increases. Then, it is discharged through the air outlet 103 on the other side wall of the mesh belt chamber 100, enters the flow channel 104 between the preheating hood 70 and the side wall of the air chamber 101, and then flows back to the hot air conveying device 5, forming a closed circulating hot air system to continuously dry the material.

[0058] S3. Acceleration Phase: At certain process nodes, such as when rapidly dehydrating materials or blowing away surface moisture, it is necessary to increase the air velocity within the conveyor belt chamber 100. At this time, the acceleration phase is initiated. The blocking mechanism 8 is activated, opening the upper opening 700 of the preheating hood 70 while keeping the lower opening 700 closed. In this state, the flow channel 104 between the preheating hood 70 and the side wall of the air chamber 101 is blocked, resulting in a blocked state.

[0059] With the upper opening 700 open, the hot air discharged from the outlet 103 of the mesh belt chamber 100 no longer flows back through the flow channel 104, but is directly drawn into the first induced draft fan 72 through the open opening 700. The first induced draft fan 72 extracts this portion of hot air with higher efficiency, forming a forced circulation, thereby significantly increasing the flow velocity of the hot air within the mesh belt chamber 100. The accelerated hot air is then reheated by the hot air conveying device 5 and sent back to the mesh belt chamber 100, achieving rapid processing of the material.

[0060] Furthermore, it also includes a backup heating step, which is performed in conjunction with the above three stages as needed.

[0061] When the hot air conveying device 5 in the corresponding air cavity 101 malfunctions or is damaged, or when the temperature inside the box 1 is insufficient due to high material humidity or large feed volume, a backup heating step is performed.

[0062] The second induced draft fan 92 starts working, and outside air enters the heat replenishment hood 90, flows through the heat replenishment device 91 (such as an electric heating tube or a steam heat exchanger) inside the heat replenishment hood 90 and is rapidly heated. The heated hot air is sent from the exhaust port of the second induced draft fan 92 into the corresponding air chamber 101, where it mixes with the original hot air or independently replenishes heat, thereby maintaining the temperature stability inside the mesh belt chamber 100.

[0063] The backup heating device 9 can serve as a supplement to the heat source, or temporarily replace the function of a certain hot air conveying device 5 when it is damaged, ensuring the continuity of drying operations and the stability of temperature, and improving the reliability and adaptability of the equipment.

[0064] The above description only illustrates preferred embodiments of the present invention, but the present invention is not limited to the above embodiments.

Claims

1. A material dryer, characterized in that: The system includes a housing (1), a multi-layer mesh belt machine, and an air supply pipe (3). The housing (1) has a mesh belt chamber (100) and an air duct chamber. The multi-layer mesh belt machine is installed in the mesh belt chamber (100). The air duct chamber is divided into independent air chambers (101) by several partitions (4). Each air chamber (101) is equipped with a hot air conveying device (5). Several air chambers (101) are equipped with preheating air duct devices (7). The housing (1) is equipped with a dehumidification device (6) that communicates with the air chambers (101). The two side walls of the mesh belt chamber (100) are respectively equipped with an air inlet (102) and an air outlet (103) that communicate with the air chambers (101). The multi-layer mesh belt machine includes three mesh belts, which are, from top to bottom, a first mesh belt (20), a second mesh belt (21), and a third mesh belt (22). The preheating air duct device (7) is located between the first mesh belt (20) and the second mesh belt (21). The preheating induced draft device (7) includes a preheating hood (70), a heat recovery device (71), and a first induced draft fan (72); the outer shell of the first induced draft fan (72) and the preheating hood (70) are both fixedly connected to the housing (1); the air inlet (102) of the first induced draft fan (72) is connected to the air supply pipe (3) through the preheating hood (70); the air outlet of the induced draft fan is connected to the air chamber (101); the heat recovery device (71) is installed inside the preheating hood (70); there is a gap between the side wall of the preheating hood (70) and the air chamber (101) to form a flow channel (104); the upper and lower ends of the preheating hood (70) are provided with openings (700) and sealing mechanisms (8). During dehumidification, the openings (700) at both ends are opened by the sealing mechanism (8), the flow channel (104) is in a blocked state, the humid air passes through the preheating hood (70) and is discharged through the dehumidification device (6); the heat recovery device (71) in the preheating hood (70) absorbs the heat of the humid air. During drying, the openings (700) at both ends are closed by the sealing mechanism (8), and the flow channel (104) is in a connected state. After the external air absorbs heat from the heat recovery device (71) and is heated, it is discharged by the first induced draft fan (72). The hot air is finally heated by the hot air conveying device (5) to form hot air and is then conveyed. The hot air passes through the air inlet (102), the air outlet (103) and the flow channel (104) in sequence and then passes through the hot air conveying device (5) to form a circulation. When it is necessary to increase the wind speed, the upper opening (700) is opened by the sealing mechanism (8), and the flow channel (104) is in a blocked state. The hot air discharged from the air outlet (103) is accelerated by the first induced draft fan (72).

2. The material dryer according to claim 1, characterized in that: The remaining air chambers (101) are equipped with a backup heating device (9); the backup heating device (9) is located between the second mesh belt (21) and the third mesh belt (22); the backup heating device (9) includes a heating cover (90), a heating device (91) and a second exhaust fan (92); the outer shell of the second exhaust fan (92) and the heating cover (90) are both fixedly connected to the box (1), the air inlet (102) of the second exhaust fan (92) is connected to the air supply pipe (3) through the heating cover (90), and the air outlet of the second exhaust fan (92) is connected to the air chamber (101); the heating device (91) is set inside the heating cover (90); there is a gap between the heating cover (90) and the side wall of the air chamber (101); During drying, when the hot air conveying device (5) in the corresponding air cavity (101) is damaged or the temperature is insufficient, the outside air is heated by the supplementary heating device (91); the heat is supplemented by the backup supplementary heating device (9) or the damaged hot air conveying device (5) is temporarily replaced.

3. A material dryer according to claim 1, characterized in that: The heat recovery device (71) consists of several heat exchange tubes, which are filled with heat-conducting oil.

4. A material dryer according to claim 1, characterized in that: The sealing device includes an upper sealing plate (80) and a lower sealing plate (81), which are slidably connected to the upper and lower ends of the control cover, respectively. The upper sealing plate (80) and the lower sealing plate (81) are respectively connected to a telescopic mechanism (82), which controls the movement of the upper sealing plate (80) and the lower sealing plate (81).

5. A material dryer according to claim 1 or 4, characterized in that: The upper part of the control cover is provided with an open section (83), and the first opening (700) at the upper end is located at the open section (83).

6. A material dryer according to claim 1, characterized in that: Each layer of mesh belt has a partition plate (15) in the middle, the partition plate (15) is inclined and fixedly connected to the box body (1); the first layer of mesh belt (20) has a collection and cleaning mechanism (11) at the partition plate (15).

7. A material dryer according to claim 6, characterized in that: The collection and cleaning mechanism (11) includes a collection trough (110) and an air extraction pipe (111). The collection trough (110) is fixedly connected to the partition plate (15) and located at the lower part of the partition plate (15). The partition plate (15) has an opening that communicates with the collection trough (110). One end of the air extraction pipe (111) is connected to the collection trough (110).

8. A material dryer according to claim 6 or 7, characterized in that: Each layer of mesh belt has an adjustable baffle (12) at its corresponding air inlet (102), and the adjustable baffles (12) are fixedly connected to each other by a vertical plate (16); a drive mechanism (13) is fixedly connected to the box (1), and the drive mechanism (13) is connected to the uppermost adjustable baffle (12); the air inlet (102) can be adjusted by the adjustable baffle (12), and a temporary storage slot (14) is formed with the partition plate (15).

9. A drying process based on the material dryer of claim 1, characterized in that, Includes the following steps: S1, Dehumidification stage: The control sealing mechanism (8) opens the openings (700) at both ends of the preheating hood (70) and puts the flow channel (104) in a blocked state. The humid air passes through the interior of the preheating hood (70) and is discharged through the dehumidification device (6). At the same time, the heat recovery device (71) inside the preheating hood (70) absorbs the heat of the humid air. S2, Drying stage: The control sealing mechanism (8) closes the openings (700) at both ends of the preheating hood (70) and keeps the flow channel (104) in a connected state; after the external air enters the preheating hood (70), it absorbs the heat from the heat recovery device (71) and heats up. It is then sent into the air chamber (101) by the first blower (72), and finally heated by the hot air conveying device (5) to form hot air and conveyed to the mesh belt chamber (100); after the hot air dries the material in the mesh belt chamber (100), it passes through the air outlet (103), the flow channel (104) and the hot air conveying device (5) in sequence to form a circulation; S3, speed-up stage: When it is necessary to increase the wind speed, the control sealing mechanism (8) opens the opening (700) at the top of the preheating cover (70) and puts the flow channel (104) in a blocked state, so that the hot air discharged from the air outlet (103) is accelerated by the first induced draft fan (72).

10. The drying process according to claim 9, characterized in that, It also includes a backup heating step: When the hot air conveying device (5) in the corresponding air cavity (101) is damaged or the temperature is insufficient, the backup heating device (9) is activated; outside air enters the heating cover (90), is heated by the heating device (91), and is then sent into the corresponding air cavity (101) by the second induced draft fan (92) to supplement heat or temporarily replace the damaged hot air conveying device (5).

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