Vacuum pulse drying device and drying method

Abstract

The invention relates to the technical field of drying equipment, and provides a vacuum pulse drying device and a drying method.The vacuum pulse drying device comprises a dryer, a vacuum mechanism and a fresh air processing mechanism; the vacuum mechanism is connected with the dryer; the fresh air treatment mechanism is used for treating fresh air and comprises a dehumidification module and a heating module; the dehumidification module is used for reducing the humidity of the fresh air, and the heating module is used for increasing the temperature of the fresh air, so that the processed fresh air reaches the preset humidity and temperature; the dryer is connected with an air inlet valve and a moisture removal valve; the air inlet valve is used for guiding treated fresh air into the dryer, and the moisture removal valve is used for guiding out gas in the dryer; the treated low-humidity and high-temperature fresh air is introduced in the emptying stage and the normal-pressure stage, so that the temperature of the materials in the drying process can be increased, the moisture migration rate is increased, and the drying rate is further increased.

Description

Technical Field

[0001] The present invention relates to the technical field of drying equipment, and in particular, to a vacuum pulsating drying device and a drying method. Background Art

[0002] Drying is an important unit operation for reducing the moisture content of materials and is an essential part of the processing of many foods, drugs, and agricultural and special products. Vacuum drying means that the environmental pressure where the material is dried is lower than the standard atmospheric pressure, and the saturated temperature of water vapor decreases as the pressure decreases, so that the moisture in the material can evaporate at a low temperature, effectively retaining the heat-sensitive components of the dried material, and the material being in an anaerobic environment can prevent oxidation during the drying process of the material.

[0003] Vacuum pulsating drying technology is a type of vacuum drying technology. By controlling the pulsating cycle of the vacuum and atmospheric pressure environments with a vacuum pump, the microscopic pores inside the material are continuously squeezed and expanded, thereby forming micro-pores, which can significantly improve moisture migration, reduce the drying time, and improve the drying quality of the material.

[0004] However, during the vacuum drying process, since the material is in a negative pressure environment for a long time and the saturated temperature of water vapor is relatively low, the temperature of the dried material is relatively low, which affects the drying rate. Summary of the Invention

[0005] The present invention provides a vacuum pulsating drying device and a drying method to solve the problem that the material temperature is relatively low during vacuum pulsating drying in the prior art and the drying rate is relatively low, and to further improve the drying rate.

[0006] The present invention provides a vacuum pulsating drying device, including: a dryer, a vacuum mechanism, and a fresh air treatment mechanism;

[0007] The vacuum mechanism is connected to the dryer;

[0008] The fresh air treatment mechanism is used for treating fresh air, and the fresh air treatment mechanism includes a dehumidification module and a heating module; the dehumidification module is used for reducing the humidity of the fresh air, and the heating module is used for increasing the temperature of the fresh air so that the treated fresh air reaches a preset humidity and temperature;

[0009] An air inlet valve and a moisture exhaust valve are connected to the dryer; the air inlet valve is used for introducing the treated fresh air into the dryer, and the moisture exhaust valve is used for discharging the gas in the dryer.

[0010] According to the vacuum pulsating drying device provided by the present invention, the dehumidification module forms a low-temperature area for condensing the moisture in the fresh air.

[0011] A vacuum pulsating drying device provided by the present invention, wherein the dehumidification module includes an evaporator.

[0012] A vacuum pulsating drying device provided by the present invention, wherein the heating module includes a condenser.

[0013] A vacuum pulsating drying device provided by the present invention, wherein the fresh air treatment mechanism further includes a compressor and an expansion valve;

[0014] The evaporator and the condenser are connected by a pipeline to form a loop for refrigerant circulation;

[0015] The compressor and the expansion valve are connected to the loop.

[0016] A vacuum pulsating drying device provided by the present invention, wherein the vacuum mechanism includes a vacuum unit and a vacuum pipeline connecting the vacuum unit and the dryer.

[0017] A vacuum pulsating drying device provided by the present invention, wherein a vacuum valve is connected to the vacuum pipeline.

[0018] A vacuum pulsating drying device provided by the present invention, wherein a pressure regulating valve is further connected to the dryer.

[0019] A vacuum pulsating drying device provided by the present invention further includes a fresh air conveying mechanism connected to the air inlet valve for inputting the treated fresh air into the dryer.

[0020] A vacuum pulsating drying device provided by the present invention, wherein the fresh air conveying mechanism includes a fresh air pipe and a fan;

[0021] The air outlet end of the fresh air pipe is in communication with the air inlet valve;

[0022] The fan is connected to the fresh air pipe.

[0023] A vacuum pulsating drying device provided by the present invention, wherein the air inlet end of the fresh air pipe is in communication with the atmosphere, and the fresh air treatment mechanism is arranged between the air inlet end and the air outlet end of the fresh air pipe for treating the inhaled air.

[0024] A vacuum pulsating drying device provided by the present invention, wherein a fresh air valve is connected to the air inlet end of the fresh air pipe.

[0025] The present invention also provides a vacuum pulsating drying method, including the following processes:

[0026] In the vacuum pumping stage, the vacuum mechanism is turned on until the pressure in the dryer reaches a preset vacuum degree;

[0027] In the vacuum pressure holding stage, the pressure is held for a period of time at the preset vacuum degree;

[0028] During the venting stage, the air inlet valve is opened to introduce fresh air into the dryer until the pressure inside the dryer returns to atmospheric pressure. Meanwhile, the moisture exhaust valve is opened to discharge the gas inside the dryer. The humidity of the fresh air is ≤8% and the temperature is 40 - 80°C.

[0029] During the atmospheric pressure stage, the fresh air is used to dry the material for a period of time under atmospheric pressure conditions.

[0030] The vacuum pumping stage, the vacuum pressure holding stage, the venting stage, and the atmospheric pressure stage are repeated.

[0031] According to a vacuum pulsating drying method provided by the present invention, the time of the venting stage is 1 - 15 minutes.

[0032] A vacuum pulsating drying device and a drying method provided by the present invention. Vacuum pulsating drying includes a vacuum pumping stage, a vacuum pressure holding stage, a venting stage, and an atmospheric pressure stage. During the venting stage, the air release valve and the moisture exhaust valve are opened. The fresh air processed by the fresh air treatment mechanism is introduced into the dryer through the air release valve, causing the dryer to gradually return to pressure. Meanwhile, the high-humidity gas inside the dryer is discharged through the moisture exhaust valve. During the atmospheric pressure stage, the processed fresh air is used to dry the material for a period of time. The humidity of the fresh air can be reduced by the dehumidification module of the fresh air treatment mechanism, and the temperature of the fresh air can be increased by the heating module, so that the processed fresh air reaches the preset humidity and temperature. Introducing the processed low-humidity and high-temperature fresh air during the venting stage and the atmospheric pressure stage can increase the temperature of the material during the drying process and accelerate the moisture migration rate, thereby further improving the drying rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 is a schematic structural diagram of a vacuum pulsating drying device provided by an embodiment of the present invention;

[0035] Figure 2 is a schematic process diagram of vacuum pulsating drying provided by an embodiment of the present invention.

[0036] Reference numerals:

[0037] 1. Dryer; 10. Air inlet valve; 11. Moisture exhaust valve; 12. Pressure regulating valve; 2. Vacuum mechanism; 20. Vacuum unit; 21. Vacuum pipeline; 22. Vacuum valve; 3. Fresh air treatment mechanism; 30. Dehumidification module; 31. Heating module; 32. Compressor; 33. Expansion valve; 4. Fresh air delivery mechanism; 40. Fresh air pipe; 41. Fan; 42. Fresh air valve. Detailed implementation manners

[0038] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0039] To facilitate the understanding of the vacuum pulsating drying device and drying method provided by the present invention, its application background is first described. Drying is an important means to reduce the moisture content of materials and is also an indispensable part of many product processing links. Vacuum drying means that the material is dried in a negative pressure environment. In a negative pressure environment, the saturated vapor pressure of water vapor is relatively low, so moisture can evaporate at a lower temperature.

[0040] Vacuum pulsating drying is a type of vacuum drying. By controlling the environment in the dryer to cycle between vacuum and atmospheric pressure, the microscopic pores in the material are continuously squeezed and expanded, which can significantly improve the moisture migration rate, reduce the drying time, and improve the drying quality of the material.

[0041] However, the inventor found that during the process of vacuum pulsating drying, since the material is in a negative pressure environment for a long time and the saturated temperature of water vapor is relatively low, the temperature of the dried material is relatively low, the moisture migration rate is slow, which affects the drying rate, and the energy consumption during the drying process is relatively high.

[0042] Based on the above, the present invention provides a vacuum pulsating drying device and drying method, which can improve the moisture migration rate by increasing the material temperature, further accelerate the drying rate, and reduce the energy consumption.

[0043] The following Figure 1 - Figure 2 describes the vacuum pulsating drying device and drying method of the present invention.

[0044] Referring to Figure 1 and Figure 2 , a vacuum pulsating drying device includes a dryer 1, a vacuum mechanism 2 and a fresh air treatment mechanism 3; wherein, the dryer 1 is a container for drying materials; the vacuum mechanism 2 is connected to the dryer 1, and the dryer 1 can be evacuated through the vacuum mechanism 2 to provide a negative pressure drying environment for the material.

[0045] The fresh air treatment mechanism 3 is used to treat fresh air. The fresh air treatment mechanism 3 includes a dehumidification module 30 and a heating module 31. Among them, the dehumidification module 30 is used to reduce the humidity of the fresh air, and the heating module 31 is used to increase the temperature of the fresh air so that the treated fresh air reaches the preset humidity and temperature. An air inlet valve 10 and a moisture exhaust valve 11 are connected to the dryer 1. Among them, the air inlet valve 10 is used to introduce the treated fresh air into the dryer 1, and the moisture exhaust valve 11 is used to discharge the gas in the dryer 1.

[0046] In actual work, the vacuum pulsating drying includes a vacuum pumping stage, a vacuum pressure holding stage, a venting stage, and an atmospheric pressure stage: In the vacuum pumping stage, the vacuum mechanism 2 is turned on to pump the vacuum of the drying container until the preset vacuum degree is reached in the dryer 1, providing a negative pressure drying environment for the material. In the vacuum pressure holding stage, it is pressurized at the preset vacuum degree for a period of time. At this time, the dryer 1 is in a negative pressure state, and the saturated vapor pressure of water is relatively low, enabling the moisture in the material to obtain a higher evaporation rate under lower temperature conditions. In the venting stage, the air release valve and the moisture exhaust valve 11 are turned on. The fresh air treated by the fresh air treatment mechanism 3 is introduced into the dryer 1 through the air release valve, gradually bringing the pressure in the dryer 1 back to normal, and at the same time, the high-humidity gas in the dryer 1 is discharged through the moisture exhaust valve 11. In the atmospheric pressure stage, in the atmospheric pressure environment, the treated fresh air is used to dry the material for a period of time. Then, the above-mentioned vacuum pumping stage, vacuum pressure holding stage, venting stage, and atmospheric pressure stage are repeated.

[0047] During the process of vacuum pulsating drying, by periodically switching the pressure, the equilibrium state of water evaporation is continuously broken, accelerating the drying rate. At the same time, the microscopic pores inside the material are continuously squeezed and expanded, thus forming micro-pores, which can significantly improve the moisture migration, reduce the drying time, and improve the drying quality of the material. In addition, the dehumidification module 30 of the fresh air treatment mechanism 3 can reduce the humidity of the fresh air, and the heating module 31 can increase the temperature of the fresh air, making the treated fresh air reach the preset humidity and temperature. Introducing the treated low-humidity and high-temperature fresh air in the venting stage and the atmospheric pressure stage can increase the temperature of the material during the drying process and accelerate the moisture migration rate, thereby further enhancing the drying rate.

[0048] It can be understood that the dehumidification module 30 is mainly used to remove the moisture in the fresh air so that the fresh air reaches the preset humidity. The dehumidification module 30 can adopt a variety of different structures and principles to achieve the dehumidification effect. For example, the condensation technology can be adopted. When the fresh air passes through the low-temperature area, the moisture inside it condenses into liquid water, thereby achieving dehumidification. The adsorption technology can also be adopted, and the moisture in the fresh air is adsorbed by the moisture absorbent to make the fresh air reach the preset humidity. Of course, in addition to this, there are many other dehumidification principles and structures, which can be specifically configured according to actual needs.

[0049] The heating module 31 is mainly used to heat the fresh air so that the fresh air reaches a preset temperature. The heating module 31 can also adopt different structures and principles to achieve the heating effect. For example, heating wires can be used for heating, or a high-temperature area can be formed by other means to heat the fresh air.

[0050] In short, the selection of the dehumidification module 30 and the heating module 31 depends on the specific requirements and conditions of the vacuum pulsation drying device. The dehumidification module 30 and the heating module 31 with different structures and principles have their own advantages and application scopes, and different forms of selection and configuration can be made according to actual needs, as long as the dehumidification and heating of the fresh air can be achieved, and the processed fresh air reaches the preset humidity and temperature.

[0051] In this embodiment, the dehumidification module 30 forms a low-temperature area. When the fresh air passes through the dehumidification module 30, the moisture in the fresh air condenses, thereby reducing the humidity of the fresh air. And the heating module 31 forms a high-temperature area. The dehumidified fresh air is heated to the preset temperature by passing through the heating module 31. In this way, fresh air with a preset humidity and temperature is formed.

[0052] Specifically, the dehumidification module 30 includes an evaporator, and the liquid refrigerant absorbs heat in the evaporator, thereby forming a low-temperature area; the heating module 31 includes a condenser, and the gaseous refrigerant liquefies and releases heat in the condenser to form a high-temperature area; the fresh air passes through the evaporator and the condenser in sequence. The moisture in the fresh air condenses in the evaporator, reducing the humidity of the fresh air, and the dehumidified fresh air is heated at the condenser, increasing the temperature of the fresh air.

[0053] Specifically, the fresh air treatment mechanism 3 further includes a compressor 32 and an expansion valve 33; the above-mentioned evaporator and condenser are connected by pipelines to form a loop for the refrigerant to circulate; the compressor 32 and the expansion valve 33 are connected to the loop, and the refrigerant circulates under the action of the compressor 32.

[0054] The liquid refrigerant absorbs heat and vaporizes in the evaporator, forming a low-temperature environment. After the fresh air passes through the evaporator, the moisture inside it condenses. The gaseous refrigerant is compressed by the compressor 32 and then enters the condenser to be condensed into a high-temperature and high-pressure liquid. Heat is released during the condensation process of the refrigerant, forming a high-temperature environment. The fresh air is heated and its temperature rises after passing through the condenser; the high-temperature and high-pressure liquid refrigerant forms a low-temperature and low-pressure liquid refrigerant after throttling through the expansion valve 33, and the liquid refrigerant enters the evaporator. In this way, a cycle is formed to achieve the dehumidification and heating of the fresh air.

[0055] Of course, the fresh air treatment mechanism 3 is not limited to the above-listed structure. In another embodiment, a combination of an adsorption dehumidification module 30 and an electric heating heating module 31 can also be adopted, so that the fresh air passes through a solid moisture absorbent to remove the moisture in the fresh air, and then the fresh air passes through a high-temperature area formed by heating wires to increase the temperature of the fresh air.

[0056] In actual work, the vacuum mechanism 2 can control the vacuum degree in the dryer 1, and the fresh air treatment mechanism 3 can treat the fresh air. During the evacuation stage and the normal pressure stage, the treated low-humidity and high-temperature fresh air is introduced to accelerate the drying rate of the material.

[0057] Refer to Figure 1 , the vacuum mechanism 2 includes a vacuum unit 20 and a vacuum pipeline 21; the vacuum unit 20 is connected to the dryer 1 through the vacuum pipeline 21. A vacuum valve 22 is connected to the vacuum pipeline 21 to control the on / off of the vacuum pipeline 21. During the vacuum pumping stage and the vacuum pressure holding stage, the vacuum valve 22 is opened to evacuate the dryer 1 or maintain the vacuum degree in the dryer 1.

[0058] A pressure regulating valve 12 is also connected to the dryer 1. During the vacuum pressure holding stage, the opening degrees of the vacuum valve 22 and the pressure regulating valve 12 can be controlled to adjust the vacuum degree in the dryer 1 so that the vacuum degree in the dryer 1 is maintained at a set value.

[0059] Specifically, the vacuum valve 22 and the pressure regulating valve 12 can be solenoid valves and their opening degrees are controlled by a controller. The controller adjusts the opening degrees of the vacuum valve 22 and the solenoid valve based on the pressure feedback in the dryer 1. During the vacuum pumping stage, the vacuum valve 22 is fully opened to evacuate the dryer 1 until the vacuum degree in the dryer 1 reaches the set value, and then it enters the vacuum pressure holding stage. The controller adjusts the opening degrees of the vacuum valve 22 and the solenoid valve to keep the vacuum degree in the dryer 1 at the set value.

[0060] In another embodiment, the pressure regulating valve 12 can also be a spring self-acting pressure regulating valve. As the vacuum unit 20 operates, the pressure in the dryer 1 continuously decreases and the vacuum degree continuously increases. When the vacuum degree in the dryer 1 is higher than the preset value, the valve core of the pressure regulating valve 12 opens under the action of the atmospheric pressure, the spring is compressed, the pressure in the dryer 1 increases, and the vacuum degree decreases until the vacuum degree in the dryer 1 decreases to the preset value. Then, under the push of the spring, the valve core closes to automatically adjust the vacuum degree in the dryer 1.

[0061] Refer to Figure 1 , the vacuum pulsation drying device further includes a fresh air conveying mechanism 4 connected to the air inlet valve 10 for inputting the treated fresh air into the dryer 1.

[0062] Specifically, the fresh air conveying mechanism 4 includes a fresh air pipe 40 and a fan 41. Among them, the air outlet end of the fresh air pipe 40 is communicated with the air inlet valve 10, and the air inlet end is communicated with the atmosphere. The fan 41 is connected to the fresh air pipe 40 to provide the conveying power for the fresh air. The fresh air treatment mechanism 3 is arranged between the air inlet end and the air outlet end of the fresh air pipe 40. During the evacuation stage and the normal pressure stage, the fan 41 is turned on, and the ambient air is introduced through the air inlet end of the fresh air pipe 40. The introduced air is treated by the fresh air treatment mechanism 3 and then conveyed into the dryer 1.

[0063] Specifically, a fresh air valve 42 is connected to the air inlet end of the fresh air pipe 40 to control the on-off of the fresh air pipe 40.

[0064] It should be noted that the above-described structure is only a part of the vacuum pulsating drying device, not all of it. Based on a specific usage scenario or environment, the vacuum pulsating drying device may also include other components or modules to meet specific drying requirements. However, since it is not the main inventive point of the present invention, other components or modules of the vacuum pulsating device will not be elaborated herein.

[0065] Next, the vacuum pulsating drying method provided by the present invention will be described. The vacuum pulsating drying method described below can be correspondingly referred to the vacuum pulsating drying device described above.

[0066] Refer to Figure 2 , a vacuum pulsating drying method, including the following processes:

[0067] S1. Evacuation stage: After supplying heat to the dryer 1, turn on the vacuum unit 20 and the vacuum valve 22 to evacuate the dryer 1 to create a negative pressure environment inside the dryer 1 until the pressure inside the dryer 1 reaches a preset vacuum degree (such as Figure 2 shown in stage a);

[0068] S2. Vacuum pressure holding stage: By controlling the opening degrees of the vacuum valve 22 and the pressure regulating valve 12, keep the vacuum degree inside the dryer 1 at the preset vacuum degree and hold the pressure for a period of time to dry the material at the preset vacuum degree (such as Figure 2 shown in stage b);

[0069] S3. Evacuation stage: Turn off the vacuum unit 20 and the vacuum valve 22, and sequentially turn on the fresh air valve 42, the air inlet valve 10, the moisture exhaust valve 11 and the fan 41. Adjust the operating states of the compressor 32 and the expansion valve 33. The fresh air is introduced through the air inlet end of the fresh air pipe 40. The introduced fresh air is condensed and dehumidified by the evaporator and then heated up in the evaporator so that the treated fresh air reaches the preset temperature and humidity. The treated fresh air is input into the dryer 1 under the driving of the fan 41. The dryer 1 gradually returns to normal pressure, and at the same time, the gas inside the dryer 1 is discharged through the moisture exhaust valve 11 (such as Figure 2 shown in stage c);

[0070] S4. At the normal pressure stage, after the pressure in the dryer 1 returns to normal pressure, the treated fresh air is used to dry the material for a period of time (such as the d stage shown in Figure 2 ), and then the compressor 32, expansion valve 33, fan 41, fresh air valve 42, air inlet valve 10, and moisture exhaust valve 11 are closed in sequence to complete one cycle of vacuum pulsating drying.

[0071] Repeat the above steps S1 - S4 until the material drying is completed.

[0072] Specifically, the humidity of the treated fresh air ≤ 8% and the temperature is 40 - 80 °C.

[0073] Specifically, in the above step S3, the time of the venting stage is 1 - 15 min.

[0074] The innovation point of the present invention lies in that: the vacuum pulsating drying includes a vacuum pumping stage, a vacuum pressure holding stage, a venting stage, and a normal pressure stage; in the venting stage, the air release valve and the moisture exhaust valve 11 are opened, and the fresh air treated by the fresh air treatment mechanism 3 is introduced into the dryer 1 through the air release valve, so that the pressure in the dryer 1 gradually returns to normal, and at the same time, the high-humidity gas in the dryer 1 is discharged through the moisture exhaust valve 11; in the normal pressure stage, the treated fresh air is used to dry the material for a period of time; the humidity of the fresh air can be reduced by the dehumidification module 30 of the fresh air treatment mechanism 3, and the temperature of the fresh air can be increased by the heating module 31, so that the treated fresh air reaches the preset humidity and temperature. Introducing the treated low-humidity and high-temperature fresh air in the venting stage and the normal pressure stage can increase the temperature of the material during the drying process and accelerate the moisture migration rate, thereby further improving the drying rate.

[0075] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vacuum pulsation drying device, It is characterized in that include: A dryer (1), a vacuum mechanism (2) and a fresh air treatment mechanism (3); The vacuum mechanism (2) is connected to the dryer (1); The fresh air processing mechanism (3) is used to process the fresh air, and the fresh air processing mechanism (3) comprises a dehumidification module (30) and a heating module (31); the dehumidification module (30) is used to reduce the humidity of the fresh air, and the heating module (31) is used to increase the temperature of the fresh air, so that the fresh air after processing reaches a preset humidity and temperature; The dryer (1) is connected to an air inlet valve (10) and a moisture removal valve (11); the air inlet valve (10) is used to allow the treated fresh air to be introduced into the dryer (1), and the moisture removal valve (11) is used to allow the gas in the dryer (1) to be discharged.

2. The vacuum pulsation drying device according to claim 1, It is characterized in that The dehumidification module (30) forms a low-temperature zone for condensing moisture in the fresh air.

3. The vacuum pulsation drying device according to claim 2, It is characterized in that The dehumidification module (30) includes an evaporator.

4. The vacuum pulsation drying device according to claim 3, It is characterized in that The heating module (31) comprises a condenser.

5. The vacuum pulsation drying device according to claim 4, It is characterized in that The fresh air processing mechanism (3) further comprises a compressor (32) and an expansion valve (33); The evaporator and the condenser are connected via a pipeline to form a loop for circulating the refrigerant; The compressor (32) and the expansion valve (33) are connected to the circuit.

6. The vacuum pulsation drying device according to claim 1, It is characterized in that The vacuum mechanism (2) comprises a vacuum unit (20) and a vacuum pipeline (21) connecting the vacuum unit (20) and the dryer (1).

7. The vacuum pulsation drying device according to claim 6, It is characterized in that The vacuum pipeline (21) is connected to a vacuum valve (22).

8. The vacuum pulsation drying device according to claim 1, It is characterized in that It also includes a fresh air delivery mechanism (4) connected to the air inlet valve (10) and used for inputting the processed fresh air into the dryer (1).

9. The vacuum pulsation drying device according to claim 8, It is characterized in that The fresh air delivery mechanism (4) comprises a fresh air duct (40) and a fan (41); The air outlet end of the fresh air pipe (40) is in communication with the air inlet valve (10); The fan (41) is connected to the fresh air duct (40).

10. A vacuum pulsation drying method, It is characterized in that Including the following processes: In the vacuuming stage, the vacuum mechanism (2) is turned on until the pressure in the dryer (1) reaches a preset vacuum degree; In the vacuum pressure holding stage, the pressure is maintained for a period of time at a preset vacuum degree; During the venting stage, the air inlet valve (10) is opened to introduce fresh air into the dryer (1) until the pressure in the dryer (1) returns to normal pressure, and at the same time, the dehumidification valve (11) is opened to discharge the gas in the dryer (1), wherein the humidity of the fresh air is ≤8% and the temperature is 40-80°C; In the normal pressure stage, the material is dried for a period of time using the fresh air under normal pressure conditions; The vacuuming stage, the vacuum pressure maintaining stage, the venting stage and the normal pressure stage are repeated.

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