A microwave dryer

Abstract

The present application discloses a microwave dryer, comprising: a cylinder having a cavity for accommodating granular materials, the cylinder being provided with a feed port and an exhaust port; a microwave magnetron being arranged on the cylinder; and a blowing pipe which is transparently arranged at the top and bottom, the blowing pipe being arranged in the cylinder and connected to the bottom of the cylinder, the blowing pipe being provided with a plurality of feeding holes; the bottom of the blowing pipe is also connected with a blowing air source channel and a discharge channel. The present application adopts pneumatic stirring to circulate granular materials, and uses microwaves as a heating source, and dries the granular materials at a relatively low heating temperature, which has the advantages of energy saving, high efficiency, less heat dissipation to the environment, and less air pollution.

Description

Technical Field

[0001] The present application belongs to the technical field of microwave drying, and specifically relates to a microwave dryer. Background Art

[0002] In the production and processing of plastic products, if the original plastic particles contain a high amount of water, it will have a great impact on the dimensional accuracy of the parts and the product quality, and even cause the parts to be scrapped. Therefore, before the parts are formed, drying the raw materials of the highly hygroscopic plastic is one of the most important links.

[0003] In order to reduce the moisture in the raw material particles, the industry generally adopts drying measures before injection molding. Usually, electric heating tube ovens or hot air ovens are used, and electric heating wires are used to heat the air in the oven. At the same time, a blower is used to blow the generated heat into the drying device to dry the plastic raw materials. However, this drying method has obvious disadvantages: 1) excessive power consumption and low energy utilization; 2) long drying cycle and low production efficiency; 3) high heating temperature for particles, which destroys the original properties of particles; 4) heat and dust will be continuously discharged to the external environment during the drying process.

[0004] Tunnel-type microwave drying equipment is also relatively common. It is mostly used for drying grain, tea, medicinal materials, feed, etc. Its main disadvantages are: 1) It occupies a large area and has high equipment cost. The equipment often occupies dozens of square meters and has limited equipment utilization, making it unsuitable for use in compactly arranged factories; 2) Because it adopts "through-type" heating, the actual heating time is short. Generally, multiple microwave tubes are used to work together at the same time, which requires high power configuration and energy consumption, and the efficiency and energy consumption ratio are very low; 3) Manual loading and unloading of materials is required, and the labor intensity is high. Summary of the invention

[0005] In view of the shortcomings or deficiencies of the above-mentioned prior art, the technical problem to be solved by the present application is to provide a microwave dryer, which adopts pneumatic stirring to circulate the granular material, and uses microwaves as a heating source to dry the granular material at a relatively low heating temperature, and has the advantages of energy saving, high efficiency, less heat dissipation to the environment and less air pollution.

[0006] To solve the above technical problems, this application is implemented through the following technical solutions:

[0007] A microwave dryer comprises: a cylinder having a cavity for accommodating granular material, the cylinder being provided with a feed port and an exhaust port; a microwave magnetron arranged on the cylinder; and a blowing pipe arranged through the top and bottom, the blowing pipe being arranged in the cylinder and connected to the bottom of the cylinder, the blowing pipe being provided with a plurality of feed holes; and a blowing air source channel and an exhaust channel being connected at the bottom of the blowing pipe.

[0008] Furthermore, in the above-mentioned microwave dryer, a cover is also provided on the blowing pipe, and the cover is arranged close to the bottom of the blowing pipe and above the feeding hole.

[0009] Furthermore, in the above-mentioned microwave dryer, the cover is detachably connected to the blowing pipe and can slide up and down along the blowing pipe.

[0010] Furthermore, in the above-mentioned microwave dryer, a protrusion structure is also provided on the blowing pipe, wherein the protrusion structure is arranged between the feeding hole and the cover.

[0011] Furthermore, in the above-mentioned microwave dryer, the cover is a hat-shaped cover.

[0012] Furthermore, in the above-mentioned microwave dryer, a bulk material tray is also installed on the top of the blowing pipe, and a granular material dispersion channel is also reserved between the top of the blowing pipe and the bulk material tray.

[0013] Furthermore, in the above-mentioned microwave dryer, the bulk material tray is detachably mounted on the top of the blowing pipe via a bracket.

[0014] Furthermore, in the above-mentioned microwave dryer, the bulk material tray is made of glass or ceramic material.

[0015] Furthermore, in the above-mentioned microwave dryer, a surface of the bulk material tray is provided with a metal nano coating.

[0016] Furthermore, in the above-mentioned microwave dryer, the bottom of the blowing pipe is connected to the first port of a three-way electric ball valve, the second port of the three-way electric ball valve is connected to the blowing air source channel, and the third port of the three-way electric ball valve is connected to the discharge channel.

[0017] Furthermore, in the above-mentioned microwave dryer, the bottom of the blowing pipe is connected to the first port of the three-way electric ball valve through a connecting pipeline.

[0018] Furthermore, in the above-mentioned microwave dryer, the connecting pipeline has a horizontal section.

[0019] Furthermore, in the above-mentioned microwave dryer, the air inlet end of the air blowing air source channel is also connected to an air source device, wherein the air source device includes a blower.

[0020] Furthermore, in the above-mentioned microwave dryer, the exhaust port and the feed port are both provided with a tube extended inwardly, wherein the aspect ratio of the tube is greater than or equal to 2.

[0021] Furthermore, in the above-mentioned microwave dryer, the cylinder includes a cylindrical structure arranged at an upper portion and a funnel-shaped structure arranged at a lower portion, wherein the cylindrical structure and the funnel-shaped structure are smoothly connected.

[0022] Furthermore, the above-mentioned microwave dryer further comprises a temperature sensor, and the temperature sensor is arranged on the upper part of the cylinder.

[0023] Furthermore, the above-mentioned microwave dryer further comprises an upper material level sensor and a lower material level sensor, and the upper material level sensor and the lower material level sensor are respectively arranged at the upper part and the lower part of the cylinder.

[0024] Furthermore, the above-mentioned microwave dryer further includes a driving power supply, and the driving power supply is electrically connected to the microwave magnetron.

[0025] Furthermore, the above-mentioned microwave dryer further comprises a control electric box, which is electrically connected to the microwave magnetron, the three-way electric ball valve and the gas source device respectively.

[0026] Furthermore, the above-mentioned microwave dryer further comprises a mounting frame with casters, and the mounting frame is used to mount the cylinder.

[0027] Compared with the prior art, this application has the following technical effects:

[0028] The present invention has low energy consumption and high energy efficiency, and utilizes the characteristics of microwave heating from the inside of water-containing particles, and cooperates with the air source device to circulate the particle material;

[0029] The present invention has a short drying time and high working efficiency. The present invention can shorten the drying time of the traditional externally heated pellet material drying method by about half. According to experimental measurements, the drying effect required by production can be achieved by using the present invention dryer for 40 minutes to 1 hour.

[0030] The drying process temperature of this application is relatively low. Due to the good room temperature wind or the circulation of gas such as N2, the particle drying process temperature is moderate, basically below 100°, and the physical and chemical properties of the particles are not damaged;

[0031] This application has little impact on the environment, and the low-temperature drying process generates little heat radiation and air pollution;

[0032] This application can realize full-automatic control, reduce labor workload, and has complete reserved interfaces, which can be easily used with existing equipment;

[0033] The overall structure of this application is compact, the floor space is small, the equipment cost is not high, and it has obvious advantages over traditional hot air dryers;

[0034] This application is not only applicable to the plastic products industry, but can also be used for drying granular materials in other industries, such as chemical fiber, textile, medicine, food, feed and other industries, and is also applicable to production processes that require drying granular materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0036] Figure 1 : Schematic diagram of the overall structure of the microwave dryer of the present application;

[0037] Figure 2 : Working principle diagram of the microwave dryer of this application;

[0038] Figure 3 : A schematic diagram of the structure of the blowing pipe in this application;

[0039] Figure 4 : A schematic diagram of the structure of the cover in this application;

[0040] Figure 5 : A schematic diagram of the structure of the bulk material tray in this application;

[0041] Figure 6 : Schematic diagram of the structure of the support in this application. DETAILED DESCRIPTION

[0042] The concept, specific structure and technical effects of the present application will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present application.

[0043] like Figure 1 and Figure 2As shown, the microwave dryer of this embodiment includes: a cylinder 02, a microwave magnetron 13 and a blowing pipe 03, wherein the cylinder 02 has a cavity for accommodating granular materials, and the cylinder 02 is provided with a feed port 09 and an exhaust port 11; the microwave magnetron 13 is arranged on the cylinder 02; the blowing pipe 03 is a hollow tube structure that is transparent from top to bottom, the blowing pipe 03 is arranged in the cylinder 02 and connected to the bottom of the cylinder 02, a plurality of feed holes 0301 are also provided on the blowing pipe 03, and the bottom of the blowing pipe 03 is also connected with a blowing air source channel 06 and a discharge channel 08. In this embodiment, pneumatic or N2-like gases are blown upward from the lowest point of the blowing tube 03 in sequence, and the upper granular materials are sequentially moved downward to realize the cyclic turning of the granular materials in sequence. At the same time, the particles are heated by the microwave magnetron 13. The characteristics of microwaves being sensitive to polar molecules and preferentially heating the moisture in the particles are utilized to heat the particles from the inside of the water-containing particles to drive out the moisture. The granular materials are stirred and the heat is evenly dissipated by pneumatic means. The airflow exchanges gas inside and outside the cylinder 02 through the air source device 07. After multiple cycles, the granular materials to be dried can lose water and achieve the drying effect under the working conditions of suitable temperature (below 100°C).

[0044] In this embodiment, the air inlet end of the blowing air source channel 06 is connected to the air outlet 0701 of the air source device 07, and further, the air source device 07 includes a blower or N2, etc. The drying process temperature of this embodiment is relatively low. Due to the use of good room temperature wind or the circulation of N2 and other gases, the particle drying process temperature is moderate, basically below 100°C, and the physical and chemical properties of the particle material are not damaged.

[0045] The air source device 07 is installed on the lower layer of the mounting frame 01 with the air inlet facing downward to prevent foreign matter from being sucked in.

[0046] Among them, the above-mentioned blower is preferably a turbo blower, and the wind pressure less than 50Kpa can meet the requirements. Through the pneumatic stirring of the granular material, it is more energy-saving, efficient, has less heat dissipation to the environment, and reduces air pollution.

[0047] The cylinder 02 includes a cylindrical structure 0201 disposed at the top and a funnel-shaped structure 0202 disposed at the bottom, wherein the cylindrical structure 0201 and the funnel-shaped structure 0202 are smoothly connected, and the cylinder 02 is preferably an integrally formed structure. The inclination angle of the funnel-shaped structure 0202 is preferably about 45°.

[0048] In this embodiment, the barrel 02 is preferably made of stainless steel, and the blowing tube 03 is also preferably made of stainless steel. The barrel 02 can also be made of a glass tube. Although the opening cost of the glass tube is higher, the wear resistance will be better.

[0049] Furthermore, an internal threaded tube 0203 is welded to the bottom of the cylinder 02, and the bottom outer wall of the blowing tube 03 is provided with an external threaded structure matching with the threaded tube. The blowing tube 03 and the cylinder 02 are fixed by the coordinated use of the external threaded structure and the internal threaded tube 0203.

[0050] The upper part of the cylinder 02 is also provided with an openable lid 0204, and after the lid 0204 is covered, the cylinder 02 forms a sealed space.

[0051] The feed port 09, exhaust port 11 and microwave magnetron 13 described above are preferably arranged on the cover 0204, that is, the top of the cylinder 02. Of course, in order to obtain a better drying effect, multiple microwave magnetrons 13 can be arranged, and they are arranged on the side or bottom of the upper part (cylindrical structure 0201) of the cylinder 02. Of course, the specific arrangement method can be uniform or non-uniform, such as uniformly arranging multiple microwave magnetrons 13 along the circumference of the circular structure. Among them, the waveguide port of the microwave magnetron 13 is arranged toward the surface of the granular material. For example, when the microwave magnetron 13 is arranged at the top of the cylinder 02, the waveguide port of the microwave magnetron 13 is arranged downward and toward the upper surface of the granular material.

[0052] Furthermore, the feed port 09 and the exhaust port 11 are both arranged parallel to the waveguide port direction of the microwave magnetron 13. The feed port 09 and the exhaust port 11 are both provided with a tube that is extended inward, wherein the aspect ratio of the tube is greater than or equal to 2, so as to reduce the microwave from being reflected from the inside of the tube to the outside of the cylinder 02 and leaking out. According to actual measurements during the prototype operation, when the aspect ratio of the tube is greater than or equal to 2, the microwave instrument can hardly detect microwave leakage at the tube mouth. In the actual measurement state of this embodiment, the diameter of the tube is 50 mm and the length is 120 mm, but when the tube diameter is thickened, the aspect ratio may need to be increased.

[0053] In this embodiment, the air outlet 11 may further be provided with a damper 12 .

[0054] This embodiment is also provided with a mounting frame 01, and the mounting frame 01 is used to mount the cylinder 02. The cylinder 02 can be uprightly seated on the mounting frame 01, and a plurality of casters are installed at the lower end of the mounting frame 01 for moving the equipment.

[0055] The blowing pipe 03 is preferably fixed at the center of the barrel 02. The blowing pipe 03 adopts a structure in which air enters from the bottom, the wall of the pipe near the bottom is opened for feeding, and the top outlet is used for discharging. The feeding hole 0301 is a vertical rectangle, and the number of holes is 4. Figure 3The structure and number of the above-mentioned feed holes 0301 are only one of the possible implementation methods, and do not limit the protection scope of the present application. Those skilled in the art can adopt other structures or other numbers of feed holes 0301 according to actual needs.

[0056] like Figure 3 As shown, the blowing tube 03 is further provided with a protrusion 0305 structure, wherein the protrusion 0305 structure is arranged between the feed hole 0301 and the cover 0304. The protrusion 0305 structure can prevent the cover 0304 from being excessively adjusted downward to contact the inner wall of the funnel-shaped structure 0202, thereby closing the feed hole 0301.

[0057] like Figure 1 , Figure 2 as well as Figure 4 As shown, the blowing tube 03 is also provided with a cover 0304, which is arranged near the bottom of the blowing tube 03 and above the feeding hole 0301. The cover 0304 is used to disperse the granular material to the feeding hole 0301, so that the granular material in the cylinder 02 can evenly enter the blowing tube 03 from all sides through the feeding hole 0301, but the height of the granular material entering the blowing tube 03 will not exceed the upper end of the feeding hole 0301.

[0058] The cover 0304 is detachably connected to the blowing tube 03 and can slide up and down along the blowing tube 03 to adjust the distance between the lower edge of the cover 0304 and the bottom of the funnel-shaped structure 0202, thereby controlling the speed at which the granular material enters the blowing tube 03.

[0059] Furthermore, the cover 0304 is a hat-shaped cover, wherein the cover 0304 is preferably made of non-metallic materials, preferably heat-resistant plastics or glass. The angle between the inclined surface of the hat-shaped cover and the horizontal plane is preferably 45°, and the inclined surface and the surface of the corresponding funnel-shaped structure 0202 are arranged perpendicular to each other. The lower end of the central circular ring of the hat-shaped cover is welded with a hat-shaped edge, which is sleeved on the blowing pipe 03 through the central ring and fixed on the blowing pipe 03 with screws.

[0060] In this embodiment, if Figure 1 , Figure 2 , Figure 3 as well as Figure 5 As shown, a bulk material tray 0303 is also installed on the top of the blowing pipe 03, wherein a granular material dispersing channel is reserved between the top of the blowing pipe 03 and the bulk material tray 0303. The bulk material tray 0303 is preferably an arc-shaped structure, wherein a small hole for installation and fixing is configured in the center of the bulk material tray 0303.

[0061] The bulk material tray 0303 is detachably mounted on the top of the blowing tube 03 through a bracket 0302. The bulk material tray 0303 is mounted on the top of the bracket 0302 through the holes configured therein to ensure that there is a space distance between the bulk material tray 0303 and the top of the blowing tube 03, which is reserved as a dispersion channel for the granular material.

[0062] like Figure 6 As shown, a circular ring is provided at the bottom of the bracket 0302, and the top of the herringbone bracket 0302 has a section of thread inserted into the hole of the bulk material tray 0303 and fixed by a nut. The circular ring is inserted into the top of the blowing tube 03, and the side can be locked on the blowing tube 03 with a set screw.

[0063] The bulk material tray 0303 is made of glass or ceramic material. Glass and ceramic materials are hard and wear-resistant and do not block microwaves. When drying and turning materials, they are used to disperse the granular materials blown up from the blowing tube 03 to prevent the granular materials from directly impacting the microwave magnetron 13. When adding materials into the blowing tube by wind, the bulk material tray 0303 can disperse the impact force of the incoming particles. The bulk material tray 0303 at the opening of the blowing tube 03 can also prevent the granular materials from entering the blowing tube 03 from the upper opening, causing the accumulation of materials in the blowing tube 03 to be too high and blockage.

[0064] Of course, a metal nano-coating can also be provided on the surface of the bulk material tray 0303, which is used to disperse the granular material blown up from the blowing tube 03 when drying and turning the material, and prevent the particles from rushing toward the microwave magnetron 13; when adding material into the blowing tube by wind force, the bulk material tray 0303 provided with a metal nano-coating can disperse the impact force of the incoming particles, and the bulk material tray 0303 at the mouth of the blowing tube 03 can also prevent the granular material from entering the blowing tube 03 from the upper mouth, causing the granular material accumulated in the blowing tube 03 to be too high and blocked, etc.

[0065] The bottom of the blowing pipe 03 is connected to the first port A of the three-way electric ball valve 05, the second port B of the three-way electric ball valve 05 is connected to the blowing air source channel 06, and the third port C of the three-way electric ball valve 05 is connected to the discharge channel 08. The three-way electric ball valve 05 is used to control the turning and discharging of materials.

[0066] The bottom of the blowing pipe 03 is connected to the first port A of the three-way electric ball valve 05 through a connecting pipe 04. The connecting pipe 04 has a horizontal section, which can prevent excessive granular materials from falling into the three-way electric ball valve 05 and accumulating, thus affecting the switching opening and closing of the three-way electric ball valve 05.

[0067] This embodiment is also equipped with a temperature sensor 15, which is arranged on the upper part of the cylinder 02, and is used to monitor the working temperature of the granular material.

[0068] This embodiment is also equipped with an upper material level sensor 16 and a lower material level sensor 17, which are respectively arranged at the upper part of the cylinder 02 and the lower part of the cylinder 02. The upper material level sensor 16 and the lower material level sensor 17 are used to monitor the material level state of the granular material.

[0069] Furthermore, this embodiment is also equipped with a driving power supply 14 , and the driving power supply 14 is electrically connected to the microwave magnetron 13 .

[0070] This embodiment is also equipped with a control box 18, which is installed on the mounting frame 01 and is electrically connected to the microwave magnetron 13, the three-way electric solenoid valve 05 and the gas source device 07. The control box 18 is equipped with a microcomputer and an electrical control switch for controlling the coordinated work of the microwave magnetron 13, the three-way electric ball valve 05 and the gas source device 07 according to a set program.

[0071] Furthermore, the control electrical box 18 is provided with a power supply interface of the feeder, and the power supply of the external feeder box discharger is connected to the corresponding position, so that the operation of the external feeder can be directly controlled to realize automatic control.

[0072] The working principle of this application is as follows (the air source device described below is explained using a blower as an example):

[0073] The feeding process of the granular material: the external feeder is started, and the granular material is first added to the cavity of the cylinder 02 through the external feeder via the feed port 09, and the feeding is stopped when the upper material level sensor 16 detects that the material is full.

[0074] Working process of turning over and heating: the control electric box 18 automatically starts the air source device 07 to blow air, and the wind blows upward through the air source channel 06 and then through the B port of the three-way electric ball valve 05 to the lower end of the blowing pipe 03, blowing the granular material that enters the blowing pipe 03 through the feed hole 0301 at the bottom upward. After the granular material hits the bulk material tray 0303 at the top, it spreads around with the wind and falls to the top layer of the granular material. When the air source device 07 is started to turn over, the microwave magnetron 13 also starts to work, and microwaves are heated from the top. During the working process, the granular material moves down and turns up layer by layer. Microwaves emit microwaves to the granular material, and dynamically and evenly heat the granular material. In the process of the bottom granular material turning up with the wind, the wind cools the granular material again, and after multiple cycles, the drying of the granular material is completed. During the drying process, the granular material is heated and cooled evenly, and there will be no local overheating or lack of heating.

[0075] Microwave irradiation drying and wind-driven turning of the pellets can be performed simultaneously, or the air supply and the working time of the microwave magnetron 13 can be controlled separately according to the set program. The program can appropriately adjust the working time ratio according to the initial temperature conditions and the drying intensity requirements. When the temperature sensor 15 detects that the heating temperature is low, the working mode of the air source device 07 can be adjusted to intermittent operation, while the microwave magnetron 13 is always working. When the set temperature is reached, the microcomputer in the control box 18 automatically controls to reduce the working intensity of the microwave magnetron 13 to prevent the pellets from being overheated. When the heating and drying time reaches the time preset by the program, the control program automatically stops heating and blowing to complete the drying of a cylinder of pellets.

[0076] Discharging process: After drying is completed, prepare for discharging. The control box 18 controls the three-way electric ball valve 05 to rotate, so that the first port A and the second port B in the three-way electric ball valve 05 are disconnected, and the first port A and the third port C are connected. Then the air source device 07 is closed, and the granular material flows downward along the blowing pipe 03 through the feed hole 0301 under the action of gravity, and enters the discharging channel 08 through the three-way electric ball valve 05 to complete the discharging. When the bottom material level sensor 17 detects that there is no material, it stops working and the working cycle ends. Wait for instructions to enter the next drying cycle, and work reciprocatingly.

[0077] It should be understood that, although the terms first, second, third, etc. may be used to describe certain components in the embodiments of the present application, these components should not be limited to these terms. These terms are only used to distinguish the components from each other. For example, without departing from the scope of the embodiments of the present application, the first so-and-so component may also be referred to as the second so-and-so component, and similarly, the second so-and-so component may also be referred to as the first so-and-so component.

[0078] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a product or system. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the product or system including the elements.

[0079] The above embodiments are only used to illustrate the technical solution of the present application but not to limit it. The present application is described in detail with reference to the preferred embodiments. It should be understood by those skilled in the art that the technical solution of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application, and should be included in the scope of the claims of the present application.

Claims

1. A microwave dryer, characterized in that: include: A cylinder having a cavity for accommodating granular material, wherein the cylinder is provided with a feed inlet and an exhaust port; A microwave magnetron, which is arranged on the cylinder; and a blowing pipe which is transparently arranged at the top and the bottom, the blowing pipe is arranged in the cylinder and connected to the bottom of the cylinder, a plurality of feeding holes are also arranged on the bottom wall of the blowing pipe, and the top of the blowing pipe is a discharge port; The bottom of the blowing pipe is also connected with a blowing air source channel and a discharge channel; The blowing pipe is also provided with a cover, which is arranged near the bottom of the blowing pipe and above the feeding hole, and the cover is detachably connected to the blowing pipe and can slide up and down along the blowing pipe; The blowing pipe is also provided with a protruding structure, wherein the protruding structure is arranged between the feeding hole and the cover, and the cover is a hat-shaped cover.

2. The microwave dryer according to claim 1, characterized in that: A bulk material tray is also installed on the top of the blowing pipe, wherein a granular material dispersing channel is reserved between the top of the blowing pipe and the bulk material tray.

3. The microwave dryer according to claim 2, characterized in that: The bulk material tray is detachably mounted on the top of the blowing pipe through a bracket.

4. The microwave dryer according to claim 2, characterized in that: The bulk material tray is made of glass or ceramic material.

5. The microwave dryer according to claim 2, 3 or 4, characterized in that: The surface of the bulk material tray is provided with a metal nano coating.

6. The microwave dryer according to claim 1, 2, 3 or 4, characterized in that: The bottom of the blowing pipe is connected to the first port of the three-way electric ball valve, the second port of the three-way electric ball valve is connected to the blowing air source channel, and the third port of the three-way electric ball valve is connected to the discharge channel.

7. The microwave dryer according to claim 6, characterized in that: The bottom of the blowing pipe is connected to the first port of the three-way electric ball valve through a connecting pipeline.

8. The microwave dryer according to claim 7, characterized in that: The connecting pipeline has a horizontal section.

9. The microwave dryer according to claim 6, characterized in that: The air inlet end of the blowing air source channel is also connected to an air source device, wherein the air source device includes a blower.

10. The microwave dryer according to claim 1, 2, 3 or 4, characterized in that: The exhaust port and the feed port are both provided with a tube that is extended inwardly, wherein the aspect ratio of the tube is greater than or equal to 2.

11. The microwave dryer according to claim 1, characterized in that: The cylinder comprises a cylindrical structure arranged at an upper portion and a funnel-shaped structure arranged at a lower portion, wherein the cylindrical structure and the funnel-shaped structure are smoothly connected.

12. The microwave dryer according to claim 1 or 2 or 3 or 4 or 11, characterized in that: A temperature sensor is also included, and the temperature sensor is arranged on the upper part of the cylinder.

13. The microwave dryer according to claim 1 or 2 or 3 or 4 or 11, characterized in that: It also includes an upper material level sensor and a lower material level sensor, and the upper material level sensor and the lower material level sensor are respectively arranged on the upper part and the lower part of the cylinder.

14. The microwave dryer according to claim 1 or 2 or 3 or 4 or 11, characterized in that: It also includes a driving power supply, which is electrically connected to the microwave magnetron.

15. The microwave dryer according to claim 1 or 2 or 3 or 4 or 11, characterized in that: It also includes a control electric box, which is electrically connected to the microwave magnetron, the three-way electric ball valve and the gas source device respectively.

16. The microwave dryer according to claim 1 or 2 or 3 or 4 or 11, characterized in that: It also includes a mounting frame with casters, and the mounting frame is used for mounting the cylinder.

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