Continuous microwave vacuum drying equipment based on sodium hydrosulfite

Abstract

The invention discloses continuous microwave vacuum drying equipment based on sodium hydrosulfite, and relates to the technical field of sodium hydrosulfite drying. The device comprises a vacuum tank, microwave generators are installed at the inner top of the vacuum tank in a linear array mode, a feeding assembly is arranged at the top of the vacuum tank, a discharging assembly is arranged at the bottom of the vacuum tank, an inner support is arranged in the vacuum tank, and an annular drying assembly is arranged on the outer side of the inner support. The mode of the stepped lantern rings is adopted, it can be guaranteed that up-down conveying does not block microwaves, the using amount of microwave generators is greatly reduced, cost is reduced, meanwhile, sodium hydrosulfite is conveyed from top to bottom, the upper microwave distance is small, much heat is generated, sodium hydrosulfite with high initial humidity is rapidly dried, the lower microwave distance is gradually increased, and the drying efficiency is improved. And the generated heat is gradually reduced, subsequent sodium hydrosulfite overheating can be prevented, drying heat control is achieved through the conveying height difference, and control is easy.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium hydrosulfite drying, and in particular to continuous microwave vacuum drying equipment based on sodium hydrosulfite. Background Art

[0002] Sulphite, a widely used chemical raw material, is primarily used in papermaking, fertilizers, metallurgy, food processing, and other fields. Due to its high hygroscopicity, it is susceptible to moisture during storage and transportation, which can cause quality changes or storage issues. To ensure the long-term stability and ease of use of sulphite, it is typically dried to remove excess moisture and prevent clumping, mold, or deterioration.

[0003] Microwave vacuum drying, a new drying technology that has emerged in recent years, offers many unique advantages, particularly when processing high-humidity materials like hydrosulfite. Microwave heating directly excites water molecules within the material, causing it to evaporate rapidly, thereby improving drying efficiency. Compared to traditional drying methods, microwave drying offers faster heating rates and more uniform moisture distribution, enabling the drying process to be completed in a shorter time. Currently available microwave vacuum drying equipment operates in batch mode and cannot meet the requirements of high-volume, high-efficiency production. A Chinese patent (publication number: CN105258480B) discloses a high-efficiency, continuous vacuum microwave dryer. The solid material being processed is fed from a feed conveyor belt to a rotary drum-type sealing device. A material distribution device evenly distributes the material onto the conveyor belt within the vacuum chamber. Heating plates located between the upper and lower conveyor belts remove some of the moisture. After being transported from the first conveyor belt to the terminal, the material falls onto the second conveyor belt. Heating from the first and second heating plates removes most of the moisture, reducing it to ≤85%. When the moisture content in the rear section is ≤15%, microwave heating and drying can save 30-40% or more energy compared to single microwave or single steam (thermal oil) heating and drying, and greatly shorten drying time. After being transported from the second material conveyor belt to the terminal, it falls onto the third material conveyor belt. The microwave device is installed on the third material conveyor belt. Under the microwave heating effect of the microwave magnetron device on the third material conveyor belt, the material enters the drying process. After drying, it passes through the discharge drum sealing device and outputs to the conveyor belt, thus completing the drying process quickly. Each layer of the material distribution device evenly distributes the material on the material conveyor belt in the vacuum chamber. The left turning device is installed in front and the right turning device is installed in the back, or the right turning device is installed in front and the left turning device is installed in the back. The distance between the left and right turning devices is ≥0.80m. A leveling device is installed behind the left and right turning devices. The material turned by the left and right turning devices is leveled after the leveling device.

[0004] This patent and the prior art have the following technical problems in actual use: 1. The above application achieves efficient and continuous vacuum microwave drying through multiple layers of material conveyor belts. However, the material conveyor belts will block and interfere with each other, and the microwave device can only be installed between the material conveyor belts. When the conveyor belt is too long or has too many layers, a large number of microwave devices are required, and the microwave devices need to be adjusted from top to bottom to generate different powers to ensure drying quality, which is costly.

[0005] 2. Since insurance powder is extremely thermally sensitive, any tiny "hot spot" may instantly exceed its decomposition temperature or even its auto-ignition point. In a closed vacuum environment, once a point is ignited, it will instantly detonate the dust and decomposed flammable gas in the entire cavity, which is extremely dangerous. In addition, insurance powder is a powder that is very easy to generate and accumulate static electricity. Under vacuum drying conditions, the air is extracted, the breakdown voltage is reduced, and static electricity is more likely to form high-energy sparks. Therefore, insurance powder needs to be dried smoothly during the vacuum drying process. The above application requires the installation of a turning device and a leveling device to achieve uniform and smooth material transportation. Static electricity is easily generated during the turning and leveling process. Therefore, how to continuously and evenly convey insurance powder is particularly important. Summary of the Invention

[0006] The purpose of the present invention is to solve the above problems and provide a continuous microwave vacuum drying device based on hydrosulfite.

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions: A continuous microwave vacuum drying device based on sodium hydrosulfite comprises a vacuum tank, a microwave generator is installed in a linear array on the top of the vacuum tank, a loading assembly is provided on the top of the vacuum tank, a unloading assembly is provided on the bottom of the vacuum tank, an inner bracket is provided inside the vacuum tank, and an annular drying assembly is provided on the outside of the inner bracket; The annular drying assembly is composed of multiple groups of annular drying lines, which are all sleeved on the outside of the inner bracket. The annular length of the annular drying line increases from top to bottom, and the lower annular drying line can be sleeved on the outside of the upper annular drying line. The annular drying line includes a material dividing assembly fixedly mounted on the inner bracket, a discharging drying line, two groups of annular turning lines and a return material drying line. The material dividing assembly is fixedly mounted on the inner bracket, and the uppermost material dividing assembly is located directly below the loading assembly. The discharging drying line and the return material drying line are both composed of two groups of synchronously reversely running conveyor belt lines. The two groups of annular turning lines are located at both ends of the discharging drying line. The annular turning line is lower than the discharging drying line and higher than the return material drying line. A rolling space is provided between the two groups of conveyor belt lines of the return material drying line.

[0008] Furthermore, the material distribution component includes a distribution hopper fixedly mounted on an inner bracket, two groups of material lines and a receiving hopper. The two groups of material lines are arranged in an inverted V shape. The distribution hopper is erected above the distribution line. A distribution plate is arranged inside the distribution hopper. The distribution plate is arranged in an inverted V shape, and the angle is the same as the angle of the two groups of material lines. The receiving hopper is located below the distribution line, and the distribution hopper and the receiving hopper are respectively located at the two ends of the distribution line. Two groups of material receiving cavities are arranged inside the receiving hopper. The two groups of conveyor belt lines in the discharging drying line are respectively located directly below the two groups of material receiving cavities. The distribution hopper in the lower annular drying line is located directly below the rolling space in the upper annular drying line.

[0009] Furthermore, a bottom skirt is provided at the bottom end of the material dividing line conveyor belt.

[0010] Furthermore, an inner baffle is provided between the two groups of the material receiving cavities.

[0011] Furthermore, the outlet of the receiving hopper in the annular drying line body gradually decreases from top to bottom.

[0012] Furthermore, the outlet of the receiving hopper in the uppermost annular drying line body is half the width of the discharging drying line body, and the outlet of the receiving hopper is close to the inner bracket, and a semicircular baffle is provided on the top of the annular turning line body.

[0013] Furthermore, the feeding assembly includes a vacuum buffer tank fixedly installed on the top of the vacuum tank, a material valve 1 is provided on the top of the vacuum buffer tank, a material storage hopper is provided on the top of the material valve 1, a material valve 2 is provided at the bottom outlet of the vacuum buffer tank, and a vacuum connecting pipe 1 is provided on the upper half of the vacuum buffer tank, and the vacuum connecting pipe 1 is connected to the external vacuum negative pressure equipment.

[0014] Furthermore, the unloading assembly includes a screw feeder fixedly installed at the bottom of the vacuum tank, a feed hopper is provided at the top of one end of the screw feeder, and the feed hopper is located directly below the rolling space in the lowest annular drying line body, a discharge port is provided at the bottom of the other end of the screw feeder, a material valve three is provided at the bottom of the discharge port, a nitrogen buffer tank is provided at the bottom end of the material valve three, a material valve four is provided at the outlet of the bottom of the nitrogen buffer tank, a nitrogen inlet and a vacuum connecting pipe two are provided at the top of the nitrogen buffer tank, the nitrogen inlet is connected to an external nitrogen source, and the vacuum connecting pipe two is connected to an external vacuum negative pressure device.

[0015] Furthermore, the side cross-section of the vacuum tank is elliptical, the inner bracket is conical, the inner bracket is made of conductive metal and is grounded through a busbar, and the grounding resistance is less than 10Ω.

[0016] The beneficial effects of the present invention are as follows: 1. The present invention adopts a stepped collar method, which can ensure that the upper and lower conveying will not block the microwaves in a limited space, greatly reducing the amount of microwave generators used and lowering costs. At the same time, the sodium hydroxide powder is conveyed from top to bottom, the upper microwave spacing is smaller, and more heat is generated, which can quickly dry the sodium hydroxide powder with high initial humidity. The lower microwave spacing gradually increases, and the heat generated gradually decreases, which can prevent the subsequent sodium hydroxide powder from overheating. The drying heat is controlled by utilizing the conveying height difference, without the need for a complex microwave generator control structure, and the control is simple.

[0017] 2. The present invention adopts the setting of a bidirectional annular drying line, which can transport the sodium hydroxide powder separately, with high transportation efficiency and high drying efficiency.

[0018] 3. The present invention adopts the settings of gravity separation, gravity gathering and gravity spreading. During the transportation process, the uniform mixing and spreading of the insurance powder are automatically completed. There is no need to set up additional turning devices and spreading devices, and no external force interference. During the transportation process, natural gravity is used to achieve efficient and uniform drying of the insurance powder, which can minimize the generation of static electricity and improve the drying safety of the insurance powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the internal structure of the vacuum tank of the present invention; Figure 2 This is a schematic diagram of the three-dimensional structure of the annular drying component of the present invention; Figure 3 This is a schematic diagram of the top view of the annular drying assembly of the present invention; Figure 4 This is a schematic diagram of the structure of the annular drying line of the present invention; Figure 5 This is a schematic diagram of the structure of the material distribution hopper and the material distribution line of the present invention; Figure 6 It is a schematic structural diagram of the feeding assembly of the present invention; Figure 7 It is a schematic structural diagram of the blanking component of the present invention.

[0020] Figure numerals: 1. vacuum tank; 2. microwave generator; 3. feeding assembly; 31. vacuum buffer tank; 32. material valve one; 33. storage hopper; 34. material valve two; 35. vacuum connecting pipe one; 4. unloading assembly; 41. screw feeder; 42. feed hopper; 43. discharge port; 44. material valve three; 45. nitrogen buffer tank; 46. material valve four; 47. nitrogen inlet; 48. vacuum connecting pipe two; 5. inner bracket; 6. material distribution hopper; 61. material distribution plate; 7. material distribution line; 71. bottom skirt; 8. material receiving hopper; 81. inner baffle; 9. material discharge drying line; 10. circular turning line; 101. semicircular baffle; 11. material return drying line; 111. rolling space. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0022] Example 1, as Figure 1-Figure 7 As shown, a continuous microwave vacuum drying equipment based on sodium hydrosulfite comprises a vacuum tank 1, a microwave generator 2 is installed in a linear array on the top inner portion of the vacuum tank 1, a loading assembly 3 is provided on the top of the vacuum tank 1, a unloading assembly 4 is provided on the bottom of the vacuum tank 1, an inner bracket 5 is provided inside the vacuum tank 1, and an annular drying assembly is provided on the outer side of the inner bracket 5; The annular drying assembly is composed of multiple groups of annular drying lines, which are all sleeved on the outside of the inner bracket 5. The annular length of the annular drying line increases from top to bottom, and the lower annular drying line can be sleeved on the outside of the upper annular drying line. The annular drying line includes a dividing assembly fixedly mounted on the inner bracket 5, a discharging drying line 9, two groups of annular turning lines 10 and a return drying line 11. The dividing assembly is fixedly mounted on the inner bracket 5, and the uppermost dividing assembly is located directly below the loading assembly 3. The discharging drying line 9 and the return drying line 11 are both composed of two groups of conveyor belt lines running synchronously in opposite directions. The two groups of annular turning lines 10 are located at both ends of the discharging drying line 9. The annular turning line 10 is lower than the discharging drying line 9 and higher than the return drying line 11. A rolling space 111 is provided between the two groups of conveyor belt lines of the return drying line 11.

[0023] The side cross-section of the vacuum tank 1 is elliptical, and the inner bracket 5 is conical. The inner bracket 5 will not affect the microwave. The inner bracket 5 is conductive metal and is grounded through the busbar. The grounding resistance is less than 10Ω. Since the entire device is connected to the inner bracket 5, the static electricity generated by the entire annular drying assembly can be derived.

[0024] The insurance powder falls from the feeding component 3 into the dividing component on the uppermost annular drying line body. The insurance powder is divided into two parts under the action of gravity, and then falls on the two groups of conveyor belt lines in the discharging drying line body 9, and is transported from the middle to both sides. For example, the left conveyor belt line body transports the insurance powder to the left annular turning line body 10, and then falls on the left conveyor belt line body in the return drying line body 11. The conveyor belt line body transports toward the middle, and both streams of insurance powder are transported toward the middle to the rolling space 111, and the insurance powder is preliminarily rolled. Only the insurance powder with high humidity and agglomerates will be rolled. The insurance powder after rolling falls into the dividing component below, and the above steps are repeated again, so that the insurance powder is divided and spread under the action of gravity, which can make the insurance powder dry evenly. Finally, the insurance powder falls into the unloading component 4 through the bottom rolling space 111, thereby realizing efficient and continuous vacuum microwave drying of insurance powder.

[0025] It should be noted that the multiple groups of annular drying lines are distributed in a cone shape as a whole. The width and length of the upper annular drying line are the smallest, and they will not block each other, so it is only necessary to set a microwave generator 2 at the inner top. The advantage of this setting is that the distance from the conveying surface of the annular drying line to the microwave generator 2 increases from top to bottom, and the microwave drying heat decreases successively. The advantage of this design is that the humidity of the insurance powder is the largest at the beginning, and the high-temperature rapid conveying method is adopted to enable the insurance powder to be dried quickly while preventing the insurance powder on the outer surface from overheating. Then it enters the annular drying line below, and the length and width of the annular drying line are increased, and the conveying time is increased, but the drying microwave heat is reduced to prevent overheating. By increasing the conveying distance and reducing the drying heat in turn, a graded drying process is adopted to quickly complete the drying of the insurance powder without causing overheating, and there is no need for graded temperature control.

[0026] Embodiment 2, based on the above embodiment, further includes that the material distribution component includes a distribution hopper 6 fixedly mounted on the inner bracket 5, two groups of material lines 7 and a receiving hopper 8, the two groups of material lines 7 are arranged in an inverted V shape, the distribution hopper 6 is erected above the distribution line 7, and a distribution plate 61 is arranged inside the distribution hopper 6, the distribution plate 61 is arranged in an inverted V shape, and the angle is the same as the angle of the two groups of material lines 7, the receiving hopper 8 is located below the distribution line 7, and the distribution hopper 6 and the receiving hopper 8 are respectively located at the two ends of the distribution line 7, two groups of material receiving cavities are arranged inside the receiving hopper 8, the two groups of conveyor belt lines in the discharge drying line 9 are respectively located directly below the two groups of material receiving cavities, and the distribution hopper 6 in the lower annular drying line is located directly below the rolling space 111 in the upper annular drying line.

[0027] The bottom end of the conveyor belt of the material distribution line 7 is provided with a bottom skirt 71.

[0028] An inner baffle 81 is provided between the two groups of receiving cavities.

[0029] The insurance powder falls on the material separation plate 61 and is classified into two strands, which fall onto the two groups of material lines 7 respectively, and fall between the conveyor belt and the bottom skirt 71, and then are transported to the corresponding material receiving cavity, and then fall flat on the material discharging drying line 9 through the material receiving cavity, and gravity is used to complete the material separation, collection and laying.

[0030] Embodiment 3, based on the above embodiment, also includes that the outlet of the receiving hopper 8 in the annular drying line body gradually decreases from top to bottom. Through this design, the insurance powder with higher humidity can be prevented from clogging the top receiving hopper 8, and the insurance powder becomes drier as it goes down. By using a small outlet, the insurance powder can be spread more evenly.

[0031] Embodiment 4, based on the above embodiment, further includes that the outlet of the receiving hopper 8 in the topmost annular drying line body is half the width of the discharging drying line body 9, and the outlet of the receiving hopper 8 is close to the inner bracket 5, and a semicircular baffle 101 is provided on the top of the annular turning line body 10.

[0032] Through this design, since the length and width of the top annular drying line are small, the radius of the annular turning line 10 is small, and the centrifugal force generated is large. At the beginning, the receiving hopper 8 spreads the wet insurance powder on the conveyor belt line of the discharge drying line 9, and only spreads half of it, close to the inner bracket 5, that is, close to the center of the annular turning line 10. Therefore, when passing through the top annular turning line 10, the stacked wet material will fall to the other side under the action of centrifugal force. For insurance powder with higher humidity, the larger centrifugal force generated by quickly passing through sharp turns is used to assist in spreading the insurance powder, thereby further improving the drying efficiency of the wet insurance powder.

[0033] Embodiment 5, on the basis of the above embodiment, further includes that the feeding assembly 3 includes a vacuum buffer tank 31 fixedly installed on the top of the vacuum tank 1, a material valve 32 is provided on the top of the vacuum buffer tank 31, a material storage hopper 33 is provided on the top of the material valve 32, a material valve 2 34 is provided at the bottom outlet of the vacuum buffer tank 31, and a vacuum connecting pipe 35 is provided on the upper half of the vacuum buffer tank 31, and the vacuum connecting pipe 35 is connected to the external vacuum negative pressure equipment.

[0034] The hydrosulfite powder is first stored in the storage hopper 33, and then the material valve 1 32 is opened to allow the hydrosulfite powder to enter the vacuum buffer tank 31. The material valve 1 32 is closed to evacuate the vacuum buffer tank 31, and then the material valve 2 34 is opened to connect with the interior of the vacuum tank 1 to add material without affecting the internal pressure stability of the vacuum tank 1.

[0035] Embodiment 6, on the basis of the above embodiment, further includes that the unloading component 4 includes a screw feeder 41 fixedly installed at the bottom of the vacuum tank 1, and a feed hopper 42 is provided at the top of one end of the screw feeder 41, and the feed hopper 42 is located directly below the rolling space 111 in the lowermost annular drying line body, and a discharge port 43 is provided at the bottom of the other end of the screw feeder 41, and a material valve three 44 is provided at the bottom of the discharge port 43, and a nitrogen buffer tank 45 is provided at the bottom end of the material valve three 44, and a material valve four 46 is provided at the outlet of the bottom of the nitrogen buffer tank 45, and a nitrogen inlet 47 and a vacuum connecting pipe two 48 are provided at the top of the nitrogen buffer tank 45, and the nitrogen inlet 47 is connected to the external nitrogen source, and the vacuum connecting pipe two 48 is connected to the external vacuum negative pressure equipment.

[0036] The insurance powder enters the screw feeder 41 through the feed hopper 42, and is then spirally transported to the discharge port 43. At this time, the interior of the nitrogen buffer tank 45 is first vacuumed through the vacuum connecting pipe 2 48, and then the material valve 3 44 is opened, and the insurance powder enters the nitrogen buffer tank 45 without affecting the internal pressure of the vacuum tank 1. Since the insurance powder is extremely flammable, if it is opened and discharged directly, too much air will flow in too fast and it is easy to explode. Therefore, protective nitrogen is injected into the nitrogen buffer tank 45 through the nitrogen inlet 47 until the nitrogen buffer tank 45 is the same as the atmospheric pressure. Finally, the material valve 46 is opened to discharge safely.

[0037] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A continuous microwave vacuum drying device based on hydrosulfite, comprising a vacuum tank (1), characterized in that: A microwave generator (2) is installed in a linear array on the inner top of the vacuum tank (1); a loading assembly (3) is provided on the top of the vacuum tank (1); a unloading assembly (4) is provided on the bottom of the vacuum tank (1); an inner bracket (5) is provided inside the vacuum tank (1); and an annular drying assembly is provided on the outer side of the inner bracket (5); The annular drying assembly is composed of multiple groups of annular drying lines, each of which is sleeved on the outside of the inner bracket (5). The annular length of the annular drying line increases from top to bottom, and the lower annular drying line can be sleeved on the outside of the upper annular drying line. The annular drying line includes a material distribution assembly fixedly mounted on the inner bracket (5), a discharge drying line (9), two groups of annular turning lines (10) and a return drying line (11). The material distribution assembly is fixedly mounted on the inner bracket (5), and the uppermost material distribution assembly is located directly below the loading assembly (3). The discharge drying line (9) and the return drying line (11) are both composed of two groups of synchronously reversely running conveyor belt lines. The two groups of annular turning lines (10) are located at both ends of the discharge drying line (9). The annular turning line (10) is lower than the discharge drying line (9) and higher than the return drying line (11). A rolling space (111) is provided between the two groups of conveyor belt lines of the return drying line (11).

2. A continuous microwave vacuum drying equipment based on hydrosulfite according to claim 1, characterized in that: The material distribution component includes a distribution hopper (6) fixedly mounted on the inner bracket (5), two groups of material lines (7) and a receiving hopper (8), the two groups of material lines (7) are arranged in an inverted V shape, the distribution hopper (6) is mounted above the distribution line (7), a distribution plate (61) is arranged inside the distribution hopper (6), the distribution plate (61) is arranged in an inverted V shape, and the included angle is the same as the included angle of the two groups of material lines (7), the receiving hopper (8) is located below the distribution line (7), and the distribution hopper (6) and the receiving hopper (8) are respectively located at the two ends of the distribution line (7), two groups of receiving cavities are arranged inside the receiving hopper (8), the two groups of conveyor belt lines in the discharge drying line (9) are respectively located directly below the two groups of receiving cavities, and the distribution hopper (6) in the lower annular drying line is located directly below the rolling space (111) in the upper annular drying line.

3. A continuous microwave vacuum drying equipment based on hydrosulfite according to claim 2, characterized in that: The bottom end of the conveyor belt of the material distribution line (7) is provided with a bottom skirt (71).

4. The continuous microwave vacuum drying equipment based on hydrosulfite according to claim 3, characterized in that: An inner baffle (81) is provided between the two groups of material receiving cavities.

5. The continuous microwave vacuum drying equipment based on hydrosulfite according to claim 4, characterized in that: The outlet of the receiving hopper (8) in the annular drying line body gradually decreases from top to bottom.

6. The continuous microwave vacuum drying equipment based on hydrosulfite according to claim 5, characterized in that: The outlet of the receiving hopper (8) in the uppermost annular drying line body is half the width of the discharging drying line body (9), and the outlet of the receiving hopper (8) is close to the inner bracket (5). A semicircular baffle (101) is provided on the top of the annular turning line body (10).

7. The continuous microwave vacuum drying equipment based on hydrosulfite according to claim 1, characterized in that: The feeding assembly (3) includes a vacuum buffer tank (31) fixedly mounted on the top of the vacuum tank (1), a material valve 1 (32) is provided on the top of the vacuum buffer tank (31), a material storage hopper (33) is provided on the top of the material valve 1 (32), a material valve 2 (34) is provided at the bottom outlet of the vacuum buffer tank (31), and a vacuum connecting pipe 1 (35) is provided on the upper half of the vacuum buffer tank (31), and the vacuum connecting pipe 1 (35) is connected to an external vacuum negative pressure device.

8. The continuous microwave vacuum drying equipment based on hydrosulfite according to claim 7, characterized in that: The unloading assembly (4) includes a screw feeder (41) fixedly mounted on the bottom of the vacuum tank (1), a feed hopper (42) is provided on the top of one end of the screw feeder (41), and the feed hopper (42) is located directly below the roller pressing space (111) in the lowest annular drying line body, a discharge port (43) is provided on the bottom of the other end of the screw feeder (41), a material valve three (44) is provided on the bottom of the discharge port (43), a nitrogen buffer tank (45) is provided on the bottom end of the material valve three (44), a material valve four (46) is provided on the outlet of the bottom of the nitrogen buffer tank (45), a nitrogen inlet (47) and a vacuum connecting pipe two (48) are provided on the top of the nitrogen buffer tank (45), the nitrogen inlet (47) is connected to an external nitrogen source, and the vacuum connecting pipe two (48) is connected to an external vacuum negative pressure device.

9. The continuous microwave vacuum drying equipment based on sodium hydrosulfite according to any one of claims 1 to 8, characterized in that: The side cross-section of the vacuum tank (1) is elliptical, the inner bracket (5) is conical, the inner bracket (5) is made of conductive metal and is grounded via a busbar, and the grounding resistance is less than 10Ω.

Images