Microwave temperature differential pressure puffing dryer

Abstract

The invention discloses a microwave variable temperature pressure difference puffing dryer, comprising a pressure tank device with a pressure tank and a vacuum system, a rotary drying device, a softening device and a microwave heating system, wherein the rotary drying device comprises a drying cylinder placed in the pressure tank, a hollow rotating shaft connected to the drying cylinder after being sealed and inserted into the pressure tank at one end, and a power mechanism capable of driving the hollow rotating shaft and the drying cylinder to rotate, the outer wall of the drying cylinder is coated with a heat exchange jacket, and the hollow rotating shaft is connected to the joint and the heat exchange jacket to form a medium passage; the softening device comprises a steam pipeline connected to an external heating device at one end and inserted into the drying cylinder in a sealed manner at the other end; the microwave heating system comprises a microwave source, a waveguide type radiation heater installed in the drying cylinder, and a sealed isolation assembly respectively connected to the microwave source and the waveguide type radiation heater. The dryer can ensure that the processed materials are heated evenly and the puffing and drying degree is consistent, and improve the production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum dryers, and in particular provides a microwave variable temperature pressure difference puffing dryer. Background Art

[0002] Fruit and vegetable chips are a high-end snack food that is popular in the world today. They are deeply loved by consumers for their natural color, crispy taste, rich nutrition and flavor.

[0003] There are three main production processes for fruit and vegetable chips that are popular in the market:

[0004] The first type: frying or vacuum low-temperature frying processing technology; this technology relies on frying to expand and dehydrate fruits and vegetables, but there is a lot of nutritional loss and it contains residual oil. The product is not resistant to storage and is not good for health if eaten frequently.

[0005] The second type: vacuum freeze-drying processing technology (freeze-drying for short); although the fruit and vegetable chips produced by this method retain the nutritional components and taste of the original fruits and vegetables to the greatest extent, due to its complex production process, expensive equipment, time-consuming production, and high energy consumption, the cost of freeze-dried products is high, which affects its large-scale promotion in the agricultural product processing industry.

[0006] The third type: variable temperature and pressure difference puffing and drying process; this method uses fresh fruits and vegetables as raw materials, and after pretreatment and pre-drying, it uses variable temperature and pressure difference puffing and drying equipment for process operation. Its unique instantaneous vacuum puffing process produces a uniform honeycomb texture structure inside the fruits and vegetables, and the products are crispy and delicious. The quality indicators such as color, aroma, taste and appearance are similar to those of freeze-dried products. This technology overcomes the drawbacks of low-temperature frying technology products with residual oil and adverse health effects, and it also does not have the problem of expensive investment and high operating costs of vacuum freeze-drying technology equipment, which restricts its popularization and promotion. Variable temperature and pressure difference puffing and drying technology is a novel, environmentally friendly and energy-saving agricultural and sideline products, especially deep processing technology for fruits and vegetables.

[0007] However, the variable temperature and pressure difference puffing drying technology of fruits and vegetables in my country is still in its infancy. There are still many problems in the existing variable temperature and pressure difference puffing drying equipment that need to be overcome or improved: ① The structural design is outdated and backward; the existing variable temperature and pressure difference puffing equipment mainly consists of a puffing tank and a vacuum tank (the volume of the vacuum tank is 5-10 times that of the puffing tank). The puffing tank is actually a universal horizontal vacuum drying tank (a horizontal pressure vessel with multiple layers of steam heating shelves built in, and a loading tray placed on the shelf), and the pressure vessel is connected to the vacuum tank through a pipeline and a pressure relief valve. During operation, first evenly spread the pre-treated fruit and vegetable raw materials into the loading tray, then put the trays in layers on the heating shelf in the puffing tank, close the tank door, heat the fruit and vegetable raw materials to the puffing temperature, keep it for a while, quickly open the pressure relief valve, connect it to the vacuum tank that has been evacuated, and the raw materials in the puffing tank will be depressurized and expanded instantly to form a uniform honeycomb structure; then heat and dehydrate under vacuum until the water content of the product reaches the requirement, then stop heating, cool to room temperature to release the vacuum, take out the tray, and unload. During the whole puffing and drying process, the material is placed in the tray and heated and evaporated in a static state. Especially after puffing, there is still a lot of water in the fruit and vegetable raw materials, which need to be heated and dried in a vacuum environment. At this time, the fruit and vegetable raw materials basically rely on the heat medium flowing in the heating plate to provide the heat required for drying to the fruit and vegetables in the form of conduction heat supply. Under the condition that other boundary conditions remain unchanged, the higher the temperature of the heating plate, the more heat is provided to the fruit and vegetable raw materials, and the faster the material dries. If the temperature of the heating plate is uneven, or the thickness of the material in the tray is uneven, the fruit and vegetables where the temperature of the heating plate is high will dry first, or the place where the material is thin in the tray will dry first, and then dry later. Due to static drying, the material cannot be turned over, and the drying phenomenon will occur in the various layers of the tray in the same puffing tank, or even in the same tray. Often, some have not yet reached the final drying requirements, and some have been over-dried, making it difficult to control the quality. In order to achieve uniform drying, the heating plate can only be controlled to ensure that the dried material does not exceed the maximum allowable temperature (the temperature at which it is not scorched or denatured) at a lower temperature, and the undried material will continue to be heated and dried, which will inevitably prolong the drying time of the whole tank of material and reduce production efficiency. ② The operation is entirely manual; the existing puffing dryer relies on manual labor to spread the fruit and vegetable raw materials on the metal tray. In order to ensure that the final product is dried evenly, workers are required to spread the materials as close to the tray as possible, with a uniform thickness and density, and then place the trays in the puffing tank for puffing and drying. When the materials are discharged, they are taken out and cleared one by one. The process is entirely manual, which is not only labor-intensive, but also unable to maintain the stability of the process and the consistency of product quality. ③ The equipment lacks versatility; the existing puffing dryer cannot perform variable temperature and pressure difference puffing drying on all fruits and vegetables. At present, most of the crisps are produced from fruit raw materials such as apples that are easy to puff and dry, while a large number of fruit and vegetable raw materials that are difficult to dehydrate and puff, such as bananas, sweet potatoes, potatoes and other high-starch fruit and vegetable crisps are rarely seen.However, this type of raw material is widely cultivated in rural areas across my country, with huge output. It is an agricultural product that urgently needs to be processed in depth to increase its added value and thus increase farmers' income.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] In order to overcome the above-mentioned defects, the present invention provides a microwave variable temperature pressure difference puffing dryer, which has a novel and reasonable structure and a high degree of automation. It can ensure that the processed materials are heated evenly and the degree of puffing and drying is consistent, thereby improving product quality; it can also shorten the heating and drying cycle by at least half, thereby improving production efficiency and reducing production costs.

[0010] The technical solution adopted by the present invention to solve its technical problems is: a microwave variable temperature pressure difference puffing dryer, including a pressure tank device, a rotary drying device, a softening device and a microwave heating system, wherein the pressure tank device has a pressure tank which is a hollow structure and a vacuum system which can act on the pressure tank and make the inner cavity of the pressure tank form a vacuum cavity; the rotary drying device has a drying cylinder, a hollow rotating shaft and a power mechanism, the drying cylinder is a hollow structure which is closed on one side and opened on the other side, the drying cylinder is movably built in the inner cavity of the pressure tank, and a feeding mechanism for inputting materials and a discharging mechanism for outputting materials are connected at the open side of the drying cylinder, and a heat exchange jacket is positioned and coated on the outer wall of the drying cylinder, one axial end of the hollow rotating shaft is placed outside the pressure tank, and is connected to a joint for communicating with an external heating device and an external cooling device, and the other axial end of the hollow rotating shaft is sealed and inserted into the inner cavity of the pressure tank, It is positioned and connected with the drying cylinder, and the hollow rotating shaft is also connected with the joint and the heat exchange jacket respectively, together forming a medium passage for the circulation of heating medium and cooling medium. In addition, the power mechanism can drive the hollow rotating shaft to rotate, thereby driving the drying cylinder to rotate relative to the pressure tank; the softening device has a steam pipe, one end of which is placed outside the pressure tank and is connected and communicated with the external heating device, and the other end of the steam pipe is sealed and inserted into the inner cavity of the pressure tank and freely inserted into the inner cavity of the drying cylinder, and a nozzle is also installed on the other end of the steam pipe; the microwave heating system has a microwave source, a sealed isolation component positioned and installed on the pressure tank and having the function of allowing microwaves to pass through but blocking air from passing through, and a waveguide type radiation heater positioned and installed in the inner cavity of the drying cylinder, and the sealed isolation component is connected to the microwave source and the waveguide type radiation heater through a waveguide tube, respectively.

[0011] As a further improvement of the present invention, the pressure tank is a horizontal hollow cylindrical structure, which has a tank body, a rear head and a front head. The tank body is a hollow cylindrical structure with openings on both axial sides. The rear head is sealed and fixed on one axial side of the tank body, and the front head is detachably positioned and installed on the other axial side of the tank body through a container flange.

[0012] The vacuum system comprises a vacuum unit, a vacuum tank connected to the vacuum unit, and a vacuum pressure transmitter installed on the pressure tank. The vacuum tank is connected to the inner cavity of the pressure tank through a vacuum pipe, and a vacuum pneumatic butterfly valve is also installed on the vacuum pipe.

[0013] As a further improvement of the present invention, the drying cylinder is a horizontal hollow cylindrical structure with one axial side closed and the other axial side forming a conical opening, and the closed side of the drying cylinder is close to the rear head, and the conical opening side is close to the front head; in addition, the closed side of the drying cylinder is also positioned and connected to the other axial end of the hollow rotating shaft, and a support component for supporting the drying cylinder is also movably connected at a position on the outer side wall of the drying cylinder and close to its conical opening, and a pushing piece for pushing materials is also provided in the inner cavity of the drying cylinder;

[0014] The feeding mechanism comprises a feeding bin and a feeding pipe located outside the pressure tank, one end of the feeding pipe is connected and communicated with the discharge port of the feeding bin, and a feeding ball valve is installed at one end of the feeding pipe, and the other end of the feeding pipe is sealed and inserted into the inner cavity of the pressure tank and freely extends into the conical opening of the drying cylinder;

[0015] The discharging mechanism comprises a hopper and a discharging pipe, one port of the hopper is connected to the bottom of the conical opening of the drying cylinder, the other port of the hopper is connected and communicated with one port of the discharging pipe, the other port of the discharging pipe is sealed and extends out of the front head, and a pneumatic discharging ball valve is also installed at the other port of the discharging pipe.

[0016] As a further improvement of the present invention, the support assembly comprises a plurality of support seats, a plurality of supporting wheels and a plurality of annular insert rings, wherein the plurality of support seats are spaced and positioned in the inner cavity of the pressure tank, the plurality of supporting wheels are respectively and correspondingly mounted on the plurality of support seats for rotation, and a circle of annular grooves are respectively concavely provided on the outer side wall of each supporting wheel, the plurality of insert rings are arranged in a ring array on the outer side wall of the drying cylinder and close to the position of the conical opening thereof, and the insert rings can be movably inserted in the annular grooves matched therewith;

[0017] The pusher is a spiral pusher belt that spirally extends from the closed side of the drying cylinder to the conical opening side thereof.

[0018] As a further improvement of the present invention, the joint adopts a swivel joint, which is connected to one end of the hollow rotating shaft by a thread or a flange, and the structure for realizing the connection between the joint and the external heating device and the external cooling device is as follows: the external heating device has a steam generator, a first main pipe, a first branch pipe and a second branch pipe, the inlet end of the first main pipe is connected and communicated with the steam outlet of the steam generator, and a first stop valve is also installed on the first main pipe, the inlet ends of the first branch pipe and the second branch pipe are respectively connected and communicated with the outlet end of the first main pipe, and the outlet end of the first branch pipe is also connected and communicated with the inlet of the joint, and a second stop valve is also installed on the second branch pipe; the external cooling device has a chiller, a second main pipe and a return pipe, the second main pipe is connected and communicated between the cold water outlet of the chiller and the first branch pipe, and a third stop valve is installed on the second main pipe, the return pipe is connected and communicated between the hollow rotating shaft and the return water outlet of the chiller, and a fourth stop valve is installed on the return pipe.

[0019] As a further improvement of the present invention, a through hole is provided on the rear cover for the hollow shaft to pass through, and a sealing member is installed between the through hole and the hollow shaft;

[0020] In addition, a bearing seat for supporting the hollow rotating shaft is movably mounted outside the hollow rotating shaft, and the bearing seat is also positioned and connected to the outer wall of the rear head.

[0021] As a further improvement of the present invention, the structure for realizing that the hollow shaft is connected with the joint and the heat exchange jacket respectively, and together forms a medium passage for the circulation of heat medium and cold medium is as follows: a conical inner head is positioned on the inner wall of the rear head, a closed cavity is formed between the inner head and the inner wall of the rear head, and the closed cavity is connected with the heat exchange jacket through the conduit A; the central pipe of the joint passes through the inner cavity of the hollow shaft and is sealed and inserted into the closed cavity; in addition, the heat exchange jacket is also connected with the inner cavity of the hollow shaft through the conduit B;

[0022] In addition, the structure for realizing that the power mechanism can drive the hollow rotating shaft to rotate is: the power mechanism has a motor, a reducer, two gears and a transmission toothed belt, wherein the input shaft of the reducer is connected to the power output shaft of the motor through a coupling, the two gears are respectively positioned and sleeved on the output shaft of the reducer and the hollow rotating shaft, and the two gears are also connected through the transmission toothed belt.

[0023] As a further improvement of the present invention, one end of the steam pipe is connected to and communicated with an outlet end of the second branch pipe.

[0024] As a further improvement of the present invention, a mounting hole for mounting the sealing isolation assembly is provided on the pressure tank; the sealing isolation assembly comprises a waveguide flange and an alumina plate having the function of allowing microwaves to pass through but blocking air from passing through, the waveguide flange is sealingly mounted in the mounting hole, and the alumina plate is sealingly mounted in the inner hole of the waveguide flange;

[0025] In addition, the microwave heating system also has an infrared temperature transmitter, which is installed on the front sealing head.

[0026] As a further improvement of the present invention, a pressurizing system is also provided, which has an air compressor, a safety valve and a pressure transmitter. The air compressor is connected and communicated with the inner cavity of the pressure tank through a pipeline, and a pneumatic stop valve is also installed on the pipeline. The safety valve and the pressure transmitter are respectively installed on the pressure tank.

[0027] The beneficial effects of the present invention are as follows: ① Compared with the prior art, the structure of the microwave variable temperature pressure difference puffing dryer of the present invention is novel and reasonable. On the one hand, it adopts the processing method of "dynamic heating", that is, the processing method of turning the material while heating, which can ensure that the processed material is heated evenly and the degree of puffing and drying is consistent, thereby improving the product quality; on the other hand, it adopts the heating method combining "contact heating (i.e. steam heating)" with "microwave electromagnetic radiation heating", which can ensure that the internal and external temperatures of the processed material are consistent and the whole is heated, which is beneficial to the processing quality, and can shorten the heating and drying cycle by at least half, thereby improving production efficiency and reducing production costs; in addition, "microwave electromagnetic radiation heating" can also complete sterilization and puffing and drying together, making puffed food safer and more hygienic. ② The microwave variable temperature pressure difference puffing dryer of the present invention has a high degree of automation, which not only reduces the labor intensity of operators, but also does not require too many operators, effectively saving production costs. ③ The microwave variable temperature and pressure difference puffing dryer of the present invention has multiple processing functions and can process fruit and vegetable raw materials with different textures and moisture contents. It has good practicality and wide applicability, creates conditions for enriching the varieties of variable temperature and pressure difference puffing drying fruit and vegetable crisps, and is beneficial to the industrial development of agricultural products. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the microwave variable temperature pressure difference puffing dryer of the present invention;

[0029] Figure 2 It is a partial cross-sectional structural schematic diagram of the microwave variable temperature pressure difference puffing dryer of the present invention;

[0030] Figure 3 for Figure 2 An enlarged structural schematic diagram of part A is shown;

[0031] Figure 4 It is a schematic diagram of the assembly relationship between the microwave heating system, the pressure tank device and the rotary drying device of the present invention.

[0032] Combined with the attached drawings, the following description is given:

[0033] 10—pressure tank; 100—tank body; 101—rear end cap; 102—front end cap; 103—inner end cap; 110—vacuum unit; 111—vacuum tank; 112—vacuum pressure transmitter; 20—drying cylinder; 21—hollow shaft; 22—power mechanism; 220—motor; 221—reducer; 23—feeding mechanism; 230—feeding bin; 231—feeding pipeline; 24—discharging mechanism; 240—receiving hopper; 241—discharging pipeline ; 25—heat exchange jacket; 26—connector; 27—support assembly; 270—support seat; 271—support wheel; 272—insert ring; 28—push piece; 30—steam pipe; 40—microwave source; 41—sealed isolation assembly; 42—waveguide radiation heater; 50—steam generator; 51—first branch pipe; 52—second branch pipe; 60—chiller; 61—second main pipe; 62—return pipe; 70—air compressor; 71—pressure transmitter. DETAILED DESCRIPTION

[0034] The following describes the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0035] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportion relationship, or adjustment of the size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. The "first", "second", "A", "B", etc. described in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0036] Embodiment 1:

[0037] Please refer to the attached Figure 1 and attached Figure 2 The figures are respectively a schematic diagram of the structure and a schematic diagram of the partial cross-section structure of the microwave variable temperature pressure difference puffing dryer according to the present invention.

[0038] The microwave variable temperature pressure difference puffing dryer of the present invention comprises a pressure tank device, a rotary drying device, a softening device and a microwave heating system, wherein the pressure tank device comprises a pressure tank 10 which is a hollow structure and a vacuum system which can act on the pressure tank 10 and make the inner cavity of the pressure tank form a vacuum cavity; the rotary drying device comprises a drying cylinder 20, a hollow rotating shaft 21 and a power mechanism 22, the drying cylinder 20 is a hollow structure which is closed on one side and opened on the other side, and the drying cylinder 20 is movably built into the inner cavity of the pressure tank 10 In the drying cylinder 20, a feeding mechanism 23 for inputting materials and a discharging mechanism 24 for outputting materials are connected at the opening side of the drying cylinder 20, and a heat exchange jacket 25 (with a guide plate arranged therein) is positioned and covered on the outer wall of the drying cylinder 20, one axial end of the hollow rotating shaft 21 is placed outside the pressure tank 10 and is connected to a joint 26 for communicating with an external heating device and an external cooling device, and the other axial end of the hollow rotating shaft 21 is sealed and inserted into the inner cavity of the pressure tank 10 and is positioned and connected to the drying cylinder 20, and The hollow shaft 21 is also connected to the joint 26 and the heat exchange jacket 25 respectively, and together they form a medium passage for the circulation of heat medium and cold medium. In addition, the power mechanism 22 can drive the hollow shaft 21 to rotate, thereby driving the drying cylinder 20 to rotate relative to the pressure tank 10; the softening device has a steam pipe 30, one end of which is placed outside the pressure tank 10 and connected and communicated with the external heating device, and the other end of the steam pipe 30 is placed in the pressure tank 10 through a seal. After being inserted into the cavity, the steam pipe 30 is freely inserted into the inner cavity of the drying cylinder 20, and a nozzle is also installed on the other end of the steam pipe 30; the microwave heating system comprises an intelligent programmable microwave source 40, a sealed isolation component 41 which is positioned and installed on the pressure tank 10 and has the function of allowing microwaves to pass through but blocking air from passing through, and a waveguide type radiation heater 42 which is positioned and installed in the inner cavity of the drying cylinder 20, and the sealed isolation component 41 is connected to the microwave source 40 and the waveguide type radiation heater 42 respectively through a waveguide tube. For details, please refer to the attached Figure 4 shown.

[0039] In this embodiment, preferably, the pressure tank 10 is a horizontal hollow cylindrical structure, which comprises a tank body 100, a rear head 101 and a front head 102. The tank body 100 is a hollow cylindrical structure with openings on both axial sides. The rear head 101 is sealed and fixed on one axial side of the tank body 100. The front head 102 is detachably positioned and installed on the other axial side of the tank body 100 through a container flange. The front head serves as a door of the pressure tank, which is convenient for installation and maintenance.

[0040] The vacuum system comprises a variable frequency vacuum unit 110, a vacuum tank 111 connected to the vacuum unit 110, and a vacuum pressure transmitter 112 installed on the pressure tank 10. The vacuum tank 111 is connected to the inner cavity of the pressure tank 10 through a vacuum pipe, and a vacuum pneumatic butterfly valve V3 is also installed on the vacuum pipe.

[0041] Preferably, the drying cylinder 20 is a horizontal hollow cylindrical structure with one axial side closed and the other axial side forming a conical opening, and the closed side of the drying cylinder 20 is close to the rear head 101, and the conical opening side is close to the front head 102; in addition, the closed side of the drying cylinder 20 is also positioned and connected to the other axial end of the hollow rotating shaft 21 through a shaft flange, and a support assembly 27 for supporting the drying cylinder 20 is also movably connected on the outer wall of the drying cylinder 20 and close to its conical opening, and a pushing piece 28 for pushing materials is also provided in the inner cavity of the drying cylinder 20;

[0042] The feeding mechanism 23 comprises a feeding bin 230 located outside the pressure tank 10 and close to the front end 102, and a stainless steel feeding pipe 231, one end of the feeding pipe 231 is connected and communicated with the discharge port of the feeding bin 230, and a feeding ball valve V1 is installed at one end of the feeding pipe 231, and the other end of the feeding pipe 231 is sealed and inserted into the inner cavity of the pressure tank 10, and freely extends into the conical opening of the drying cylinder 20;

[0043] The discharging mechanism 24 comprises a hopper 240 and a stainless steel discharging pipe 241, one port of the hopper 240 is received below the conical opening of the drying cylinder 20, the other port of the hopper 240 is connected and communicated with one port of the discharging pipe 241, the other port of the discharging pipe 241 is sealed and extends out of the front head 102, and a pneumatic discharging ball valve V2 is also installed at the other port of the discharging pipe 241.

[0044] Further preferably, the support assembly 27 has a plurality of support seats 270, a plurality of support wheels 271 and a plurality of annular insert rings 272, see attached Figure 3 As shown, a plurality of the support seats 270 are spaced and positioned in the inner cavity of the pressure tank 10, a plurality of the support wheels 271 are rotatably mounted on the plurality of the support seats 270 respectively, and a circle of annular grooves are concavely provided on the outer wall of each of the support wheels 271, a plurality of the insert rings 272 are arranged in an annular pattern on the outer wall of the drying cylinder 20 and close to the position of the conical opening thereof, and the insert rings 272 can be movably inserted in the annular grooves matched therewith;

[0045] The pushing member 28 is a spiral pushing belt that spirally extends from the closed side of the drying cylinder 20 to the conical opening side thereof, and the spiral pushing belt can be configured as a plurality of belts according to production requirements.

[0046] Further preferably, the joint 26 is a rotary joint, which is connected to one end of the hollow shaft 21 by a thread or a flange, and the structure for connecting the joint 26 with the external heating device and the external cooling device is as follows: the external heating device has a steam generator 50, a first main pipe, a first branch pipe 51 and a second branch pipe 52, the inlet end of the first main pipe is connected and communicated with the steam outlet of the steam generator 50, and a first stop valve V4 is also installed on the first main pipe, and the inlet ends of the first branch pipe 51 and the second branch pipe 52 are respectively connected to the outlet end of the first main pipe and The outlet end of the first branch pipe 51 is also connected and connected with the inlet of the joint 26, and a second stop valve V5 is also installed on the second branch pipe 52; the external cooling device comprises a chiller 60, a second main pipe 61 and a return pipe 62, the second main pipe 61 is connected and connected between the cold water outlet of the chiller 60 and the first branch pipe 51, and a third stop valve V6 is installed on the second main pipe 61, the return pipe 62 is connected and connected between the hollow shaft 21 and the return water port of the chiller 60, and a fourth stop valve V7 is installed on the return pipe 62.

[0047] Further preferably, a through hole is provided on the rear end cover 101 for the hollow shaft 21 to pass through, and a seal is installed between the through hole and the hollow shaft 21, such as a stuffing box or a double-end mechanical seal structure, to ensure that the vacuum or pressure in the pressure tank does not leak when the hollow shaft rotates;

[0048] In addition, a bearing seat for supporting the hollow shaft is movably mounted outside the hollow shaft 21 , and the bearing seat is also positioned and connected to the outer wall of the rear head 101 .

[0049] Further preferably, the structure of realizing that the hollow shaft 21 is connected with the joint 26 and the heat exchange jacket 25 respectively, and together constitutes a medium passage for the circulation of heat medium and cold medium is as follows: a conical inner head 103 is positioned on the inner wall of the rear head 101, a closed cavity is formed between the inner head 103 and the inner wall of the rear head 101, and the closed cavity is connected with the heat exchange jacket 25 through the conduit A; the central pipe of the joint 26 passes through the inner cavity of the hollow shaft 21 and is sealed and inserted into the closed cavity; in addition, the heat exchange jacket 25 is also connected with the inner cavity of the hollow shaft 21 through the conduit B;

[0050] In addition, the structure for realizing that the power mechanism 22 can drive the hollow rotating shaft 21 to rotate is as follows: the power mechanism 22 has a variable frequency motor 220, a reducer 221, two gears and a transmission toothed belt, wherein the input shaft of the reducer 221 is connected to the power output shaft of the motor 220 through a coupling, the two gears are respectively positioned and sleeved on the output shaft of the reducer 221 and the hollow rotating shaft 21, and the two gears are also connected for transmission through the transmission toothed belt.

[0051] Further preferably, one end of the steam pipe 30 is connected to and communicated with an outlet end of the second branch pipe 52 .

[0052] Further preferably, a mounting hole for mounting the sealing isolation assembly 41 is provided on the pressure tank 10; the sealing isolation assembly 41 comprises a waveguide flange and an alumina plate having the function of allowing microwaves to pass through but blocking air from passing through; the waveguide flange is sealed and mounted in the mounting hole, and the alumina plate is sealed and mounted in the inner hole of the waveguide flange through a sealing gasket;

[0053] In addition, the microwave heating system also has an infrared temperature transmitter, which is installed on the front sealing head 102.

[0054] In this embodiment, preferably, a pressurizing system is also provided, which has an air compressor 70, a safety valve V12 and a pressure transmitter 71. The air compressor 70 is connected and communicated with the inner cavity of the pressure tank 10 through a pipeline, and a pneumatic stop valve V11 is also installed on the pipeline. The safety valve V12 and the pressure transmitter 71 are respectively installed on the pressure tank 10.

[0055] In addition, the present invention also provides a processing method of the microwave variable temperature pressure difference puffing dryer, which is specifically described as follows:

[0056] Embodiment 2:

[0057] Processing method of apple chips using the microwave variable temperature pressure difference puffing dryer:

[0058] Step ①: Turn on the power, start the automatic control system (including PC and PLC controller), input relevant parameters and programs through the touch screen human-machine dialogue interface of the PLC controller, press the start button to enter operation;

[0059] Start the vacuum unit 110 and set the vacuum degree of the pressure tank 10 to -0.098 MPa; start the steam generator 50 and set the steam temperature to 100° C.; start the chiller 60 and set the chilled water temperature to -15° C.;

[0060] Step ②, when the steam generator 50 generates 100°C steam, the motor 220 is controlled to start, and after the power is transmitted through the reducer 221, two gears, a transmission belt and the hollow shaft 21, the drying cylinder 20 is driven to rotate clockwise at a speed of 15r / min;

[0061] After the drying cylinder 20 rotates for a certain period of time, the feed ball valve V1 is controlled to open, and the apple slices in the feed bin 230 fall into the conical opening of the drying cylinder 20 after passing through the feed ball valve V1 and the feed pipe 231. The pusher 28 rotates with the drying cylinder to continuously push the apple slices to the closed side of the drying cylinder. When the feeding is completed, the feed ball valve V1 is controlled to close, but the drying cylinder 20 continues to rotate.

[0062] Step ③, controlling the first stop valve V4 and the second stop valve V5 to open, wherein one path of steam enters the heat exchange jacket 25 through the first branch pipe 51, the joint 26, and the closed cavity to heat the apple slices; the other path of steam passes through the second branch pipe 52, the steam pipe 30, and the nozzle, and is sprayed onto the surface of the continuously rolling apple slices, and after the set time for the apple slices to be evenly wetted and softened is reached, controlling the second stop valve V5 to close;

[0063] Step ④, control the intelligent program-controlled microwave source 40 to start, and the generated microwave is transmitted to the waveguide type radiation heater 42 through the waveguide and the sealed isolation component 41, so as to radiantly heat the apple slices after being wetted and softened. At this time, the apple slices continue to be heated by the steam from the heat exchange jacket 25 and the closed cavity; the infrared temperature transmitter senses the temperature information of the apple slices in real time online and transmits it to the control system. When the control system controls the microwave feed power to make the apple slices reach a material temperature of 80°C, the insulation treatment is set for a time;

[0064] Step ⑤, opening the vacuum valve, the pressure tank 10 is depressurized, and the water in the apple slices is instantly vaporized and expanded to form a mesh sponge structure;

[0065] The pressure tank 10 is kept vacuum, the heat exchange jacket 25 and the steam in the closed chamber are kept heated, the waveguide type radiation heater 42 is kept radiantly heated, and then the apple slices are dried at 80° C. for 20 minutes, and then the drying is finished;

[0066] Step ⑥, close the intelligent programmable microwave source 40 and the first stop valve V4, open the third stop valve V6 and the fourth stop valve V7, and the -15°C coolant enters the heat exchange jacket 25 through the first branch pipe 51, the joint 26, and the closed cavity, and then returns to the chiller 60 through the hollow shaft 21 and the return pipe 62, so as to realize cyclic cooling of the apple slices. After the temperature of the apple slices drops to 20°C, close the third stop valve V6, the fourth stop valve V7, the vacuum pneumatic butterfly valve V3, the vacuum unit 110 and the motor 220, etc.;

[0067] Step ⑦, open the vent valve V9, and control the motor 220 to run counterclockwise at a speed of 20r / min, then open the pneumatic discharge ball valve V2, and the apple chips are pushed by the pusher 28 to rotate out of the conical opening of the drying cylinder 20 from the inside to the outside, and fall into the receiving hopper 240, and then discharged through the discharge pipe 241 and the pneumatic discharge ball valve V2.

[0068] Embodiment 3:

[0069] Processing method of French fries using the microwave variable temperature pressure difference puffing dryer:

[0070] Step ①: Turn on the power, start the automatic control system (including PC and PLC controller), input relevant parameters and programs through the touch screen human-machine dialogue interface of the PLC controller, press the start button to enter operation;

[0071] Start the vacuum unit 110 and set the vacuum degree of the pressure tank 10 to -0.098 MPa; start the steam generator 50 and set the steam temperature to 120° C.; start the chiller 60 and set the chilled water temperature to -15° C.; start the air compressor 70 and set the air pressure to 0.4 MPa;

[0072] Step ②, when the steam generator 50 generates 120°C steam, the motor 220 is controlled to start, and after the power is transmitted through the reducer 221, two gears, a transmission belt and the hollow shaft 21, the drying cylinder 20 is driven to rotate clockwise at a speed of 15r / min;

[0073] After the drying cylinder 20 rotates for a certain period of time, the feed ball valve V1 is controlled to open, and the French fries to be processed in the feed bin 230 fall into the conical opening of the drying cylinder 20 after passing through the feed ball valve V1 and the feed pipe 231. The pusher 28 rotates with the drying cylinder to continuously push the French fries to the closed side of the drying cylinder. When the feeding is completed, the feed ball valve V1 is controlled to close, but the drying cylinder 20 continues to rotate.

[0074] Step ③, control the first stop valve V4 and the second stop valve V5 to open, one path of steam passes through the first branch pipe 51, the joint 26, and the closed cavity to enter the heat exchange jacket 25 to heat the French fries; the other path of steam passes through the second branch pipe 52, the steam pipe 30 and the nozzle, and is sprayed onto the surface of the French fries that are constantly rolling. After the set time for the French fries to be evenly wetted and softened is reached, control the second stop valve V5 to close;

[0075] Step ④, control the pneumatic stop valve V11 to open, input the purified and filtered compressed air into the pressure tank 10, and maintain the pressure in the pressure tank 10 at 0.4 MPa;

[0076] Step ⑤, control the intelligent programmable microwave source 40 to start, and the generated microwave is transmitted to the waveguide type radiation heater 42 through the waveguide and the sealed isolation component 41, so as to radiate and heat the French fries after wet and softening, and accelerate the internal starch gelatinization of the French fries under high temperature and high pressure conditions. At this time, the French fries continue to be heated by the steam from the heat exchange jacket 25 and the closed cavity; the infrared temperature transmitter senses the temperature information of the French fries in real time online and transmits it to the control system. When the control system controls the microwave feed power to make the French fries reach a material temperature of 110°C, the insulation treatment is set for a time;

[0077] Step ⑥, close the pneumatic stop valve V11 and the air compressor 70; open the vacuum valve, the pressure tank 10 is depressurized, and the water in the French fries expands and vaporizes to form a porous structure;

[0078] The vacuum in the pressure tank 10 is maintained, the heat exchange jacket 25 and the steam in the closed cavity are heated, and the waveguide type radiation heater 42 is radiated and heated. That is, the French fries are dried at 95° C. for 30 minutes, and then the drying is completed.

[0079] Step ⑦, close the intelligent programmable microwave source 40 and the first stop valve V4, open the third stop valve V6 and the fourth stop valve V7, and the -15°C coolant enters the heat exchange jacket 25 through the first branch pipe 51, the joint 26, and the closed cavity, and then returns to the chiller 60 through the hollow shaft 21 and the return pipe 62 to achieve cyclic cooling of the French fries. After the French fries are cooled to room temperature, the third stop valve V6, the fourth stop valve V7, the vacuum pneumatic butterfly valve V3, the vacuum unit 110 and the motor 220 are closed;

[0080] Step ⑧, open the vent valve V9, and control the motor 220 to run counterclockwise at a speed of 20r / min, then open the pneumatic discharge ball valve V2, and the French fries are pushed by the pusher 28 to rotate out of the conical opening of the drying cylinder 20 from the inside to the outside, and fall into the receiving hopper 240, and then discharged through the discharge pipe 241 and the pneumatic discharge ball valve V2.

[0081] In summary, the microwave variable temperature pressure difference puffing dryer of the present invention has a novel, reasonable and highly automated structure, which can ensure that the processed materials are heated evenly and the puffing and drying degree is consistent, thereby improving the product quality; it can also shorten the heating and drying cycle by at least half, thereby improving production efficiency and reducing production costs.

[0082] The above description is only a preferred embodiment of the present invention, but is not intended to limit the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A microwave variable temperature pressure difference puffing dryer, characterized in that: The invention comprises a pressure tank device, a rotary drying device, a softening device and a microwave heating system, wherein the pressure tank device comprises a pressure tank (10) which is a hollow structure and a vacuum system which can act on the pressure tank (10) and make the inner cavity of the pressure tank form a vacuum cavity; the rotary drying device comprises a drying cylinder (20), a hollow rotating shaft (21) and a power mechanism (22); the drying cylinder (20) is a hollow structure which is closed on one side and open on the other side; the drying cylinder (20) is movably built into the inner cavity of the pressure tank (10); and the vacuum system is operated in the drying cylinder (20). ) is connected to an opening side of the pressure tank (10) with a feeding mechanism (23) for inputting materials and a discharging mechanism (24) for outputting materials, and a heat exchange jacket (25) is positioned and covered on the outer wall of the drying cylinder (20), one axial end of the hollow rotating shaft (21) is placed outside the pressure tank (10) and is connected to a joint (26) for communicating with an external heating device and an external cooling device, the other axial end of the hollow rotating shaft (21) is sealed and inserted into the inner cavity of the pressure tank (10) and is positioned and connected to the drying cylinder (20), and the hollow rotating shaft (21) is also The two heat exchangers (25) are respectively connected to the joint (26) and the heat exchange jacket (25), and together form a medium passage for the circulation of heating medium and cooling medium. In addition, the power mechanism (22) can drive the hollow shaft (21) to rotate, thereby driving the drying cylinder (20) to rotate relative to the pressure tank (10); the softening device has a steam pipe (30), one end of which is placed outside the pressure tank (10) and connected to and communicated with the external heating device, and the other end of the steam pipe (30) is placed in the pressure tank (10) through a seal. ) and freely inserted into the inner cavity of the drying cylinder (20), and a nozzle is also installed on the other end of the steam pipe (30); the microwave heating system comprises a microwave source (40), a sealing isolation component (41) positioned and installed on the pressure tank (10) and having the function of allowing microwaves to pass through but blocking air from passing through, and a waveguide type radiation heater (42) positioned and installed in the inner cavity of the drying cylinder (20), and the sealing isolation component (41) is connected to the microwave source (40) and the waveguide type radiation heater (42) respectively through a waveguide tube; The pressure tank (10) is a horizontal hollow cylindrical structure, comprising a tank body (100), a rear head (101) and a front head (102); the tank body (100) is a hollow cylindrical structure with openings on both axial sides; the rear head (101) is sealed and fixed on one axial side of the tank body (100); and the front head (102) is detachably positioned and installed on the other axial side of the tank body (100) through a container flange; the vacuum system comprises a vacuum unit (110), a vacuum tank (111) connected to the vacuum unit (110), and a vacuum pressure transmitter (112) installed on the pressure tank (10); the vacuum tank (111) is connected to the inner cavity of the pressure tank (10) through a vacuum pipeline, and a vacuum pneumatic butterfly valve is also installed on the vacuum pipeline; The drying cylinder (20) is a horizontal hollow cylindrical structure with one axial side closed and the other axial side forming a conical opening, and the closed side of the drying cylinder (20) is close to the rear end cover (101), and the conical opening side is close to the front end cover (102); in addition, the closed side of the drying cylinder (20) is also positioned and connected to the other axial end of the hollow rotating shaft (21), and a support component (27) for supporting the drying cylinder (20) is also movably connected at a position on the outer wall of the drying cylinder (20) and close to its conical opening, and a pushing member (28) for pushing materials is also provided in the inner cavity of the drying cylinder (20); the feeding mechanism (23) has a feeding bin (230) and a feeding pipe (231) located outside the pressure tank (10), and one end of the feeding pipe (231) is connected to the feeding bin (230) and ... The outlet of the feed bin (230) is connected and communicated with the outlet of the feed bin (230), and a feed ball valve is installed at one end of the feed pipe (231). The other end of the feed pipe (231) is sealed and inserted into the inner cavity of the pressure tank (10) and freely extends into the conical opening of the drying cylinder (20); the discharge mechanism (24) comprises a hopper (240) and a discharge pipe (241). One end of the hopper (240) is received below the conical opening of the drying cylinder (20), and the other end of the hopper (240) is connected and communicated with one end of the discharge pipe (241). The other end of the discharge pipe (241) is sealed and extends out of the front head (102), and a pneumatic discharge ball valve is installed at the other end of the discharge pipe (241); The support assembly (27) comprises a plurality of support seats (270), a plurality of supporting wheels (271) and a plurality of annular insert rings (272), wherein the plurality of support seats (270) are spaced and positioned in the inner cavity of the pressure tank (10), the plurality of supporting wheels (271) are rotatably mounted on the plurality of support seats (270) respectively and correspondingly, and a circle of annular grooves are respectively recessed on the outer wall of each supporting wheel (271), the plurality of insert rings (272) are arranged in an annular pattern on the outer wall of the drying cylinder (20) and close to the conical opening thereof, and the insert rings (272) can be movably inserted into the annular grooves matched therewith; the pushing member (28) is a spiral pushing belt that spirally extends from the closed side of the drying cylinder (20) to the conical opening side thereof; The joint (26) is a swivel joint, which is connected to one end of the hollow rotating shaft (21) by means of a thread or a flange, and the structure for realizing the connection between the joint (26) and the external heating device and the external cooling device is as follows: the external heating device comprises a steam generator (50), a first main pipe, a first branch pipe (51) and a second branch pipe (52), the inlet end of the first main pipe is connected to and communicated with the steam outlet of the steam generator (50), and a first stop valve is installed on the first main pipe, the inlet ends of the first branch pipe (51) and the second branch pipe (52) are respectively connected to and communicated with the outlet end of the first main pipe, and the first branch pipe (51) and the second branch pipe (52) are respectively connected to and communicated with the outlet end of the first main pipe. The outlet end of the branch pipe (51) is also connected to and communicated with the inlet end of the joint (26), and a second stop valve is also installed on the second branch pipe (52); the external cooling device comprises a chiller (60), a second main pipe (61) and a return pipe (62); the second main pipe (61) is connected to and communicated between the cold water outlet of the chiller (60) and the first branch pipe (51), and a third stop valve is installed on the second main pipe (61); the return pipe (62) is connected to and communicated between the hollow shaft (21) and the return water port of the chiller (60), and a fourth stop valve is installed on the return pipe (62).

2. The microwave variable temperature pressure difference puffing dryer according to claim 1, characterized in that: The rear head (101) is provided with a through hole for the hollow shaft (21) to pass through, and a sealing member is installed between the through hole and the hollow shaft (21); in addition, a bearing seat for supporting the hollow shaft is movably mounted outside the hollow shaft (21), and the bearing seat is also positioned and connected to the outer wall of the rear head (101).

3. The microwave variable temperature pressure difference puffing dryer according to claim 1, characterized in that: The structure for realizing that the hollow shaft (21) is connected to the joint (26) and the heat exchange jacket (25) respectively, and together they form a medium passage for the circulation of heat medium and cold medium is as follows: a conical inner head (103) is positioned on the inner wall of the rear head (101), a closed cavity is formed between the inner head (103) and the inner wall of the rear head (101), and the closed cavity is connected to the heat exchange jacket (25) through a conduit A; the central tube of the joint (26) passes through the inner cavity of the hollow shaft (21) and is sealed and inserted into the closed cavity; in addition, the heat exchange jacket (25) is also connected to the inner cavity of the hollow rotating shaft (21) through the conduit B; in addition, the structure for realizing that the power mechanism (22) can drive the hollow rotating shaft (21) to rotate is: the power mechanism (22) has a motor (220), a reducer (221), two gears and a transmission toothed belt, wherein the input shaft of the reducer (221) is connected to the power output shaft of the motor (220) through a coupling, and the two gears are respectively positioned and sleeved on the output shaft of the reducer (221) and the hollow rotating shaft (21), and the two gears are also connected through the transmission toothed belt.

4. The microwave variable temperature pressure difference puffing dryer according to claim 1, characterized in that: One end of the steam pipe (30) is connected to and communicates with the outlet end of the second branch pipe (52).

5. The microwave variable temperature pressure difference puffing dryer according to claim 1, characterized in that: The pressure tank (10) is provided with a mounting hole for mounting the sealing isolation assembly (41); the sealing isolation assembly (41) comprises a waveguide flange and an alumina plate having the function of allowing microwaves to pass through but blocking air from passing through; the waveguide flange is sealingly mounted in the mounting hole, and the alumina plate is sealingly mounted in the inner hole of the waveguide flange; in addition, the microwave heating system further comprises an infrared temperature transmitter, which is mounted on the front sealing head (102).

6. The microwave variable temperature pressure difference puffing dryer according to claim 1, characterized in that: A pressurizing system is also provided, the pressurizing system comprising an air compressor (70), a safety valve and a pressure transmitter (71); the air compressor (70) is connected and communicated with the inner cavity of the pressure tank (10) through a pipeline, and a pneumatic stop valve is also installed on the pipeline; the safety valve and the pressure transmitter (71) are respectively installed on the pressure tank (10).

Images