Energy-saving vacuum freeze-drying device

Abstract

The utility model particularly discloses an energy-saving vacuum freeze-drying device which is characterized in that a drying box is connected with a vacuumizing system, sealing doors are arranged at the two ends of the drying box, an inner cavity of the drying box is sequentially divided into a freezing chamber, a sublimation drying chamber, a buffer chamber, an analysis drying chamber and a discharging buffer chamber through the sealing doors, and conveying belts capable of independently running are arranged in all the chambers. The freezing chamber is connected with the heat pump evaporator through an evaporator cold air circulating pipeline, the analysis drying chamber is connected with the heat pump condenser through a first condenser hot water circulating pipeline, the sublimation drying chamber is connected with the heat pump condenser through a second condenser hot water circulating pipeline, and the heat pump evaporator is connected with the heat pump condenser through a pipeline. And a heat pump compressor is arranged on a connecting pipeline between the heat pump evaporator and the heat pump condenser. The heat pump energy recovery system is adopted to use heat generated by refrigeration of the freezing chamber as a heating heat source of the sublimation drying chamber and the desorption drying chamber, energy consumption is saved, continuous operation of materials is achieved, and production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to freeze drying equipment technical field, specifically is a kind of energy-saving vacuum freeze drying device. BACKGROUND

[0002] Vacuum freeze dryer is the equipment that realizes dehydration drying of object by heating sublimation of water frozen into solid in vacuum environment, and is commonly used for dehydration drying of food, Chinese medicinal materials, biological products, nanometer molecular materials and the like.The purpose of freezing treatment is to prevent nutrient loss of material due to high temperature in vacuum drying process, and to maintain original color, taste and nutrient components of material.

[0003] At present, the existing vacuum freeze drying technology generally has only one through cavity, and drying process includes three stages of pre-freezing stage, sublimation drying stage and desorption drying stage, which are alternately performed, and the time is relatively long, and heating is performed by using external steam, heat conducting oil or electricity. Water in material is rapidly frozen into ice crystal in pre-freezing stage, so as to reduce damage of ice crystal to material. In sublimation drying stage, ice crystal is directly sublimated into water vapor by providing heat to frozen object to increase temperature in vacuum environment, so as to remove most of water. In desorption drying stage, residual water is further removed, and drying process is completed. The drying process is relatively long. Chinese patent application CN106468500A discloses an energy-saving freeze drying device and freeze drying method thereof, which mainly includes vacuum pump, condenser and drying box. Refrigerating unit provides cold source for material freezing and water capture, and heat conducting oil heating system provides heat source for material to be dried. The energy consumption is relatively high. SUMMARY

[0004] The utility model discloses a kind of energy-saving vacuum freeze drying devices for solving the problems of high energy consumption and long time of the vacuum freeze dryer in prior art, which can be continuously produced with lower energy consumption.

[0005] To solve the above technical problems, the utility model discloses a drying box, the drying box is connected with vacuumizing system by pipeline, the feeding end and the discharging end of the drying box are equipped with sealing doors, and the structure is characterized by: the internal cavity of the drying box is separated into freezing chamber, sublimation drying chamber, buffer chamber, desorption drying chamber and discharging buffer chamber in sequence by sealing doors from the feeding end to the discharging end, conveying belts for conveying shelves from the feeding end to the discharging end are arranged in the freezing chamber, sublimation drying chamber, buffer chamber, desorption drying chamber and discharging buffer chamber, the freezing chamber is connected with heat pump evaporator through evaporator cold air circulation pipeline, the desorption drying chamber is connected with heat pump condenser through first condenser hot water circulation pipeline, the sublimation drying chamber is connected with heat pump condenser through second condenser hot water circulation pipeline, the heat pump evaporator and the heat pump condenser are connected by pipeline, and heat pump compressor is arranged on the connecting pipeline between the heat pump evaporator and the heat pump condenser.

[0006] The vacuum system comprises a first vacuum pump and a second vacuum pump, the first vacuum pump is connected with the freezing chamber, the sublimation drying chamber and the buffer chamber through the first vacuum pipeline, and the second vacuum pump is connected with the buffer chamber, the resolution drying chamber and the discharge buffer chamber through the second vacuum pipeline.

[0007] The automatic pressure regulating valve is arranged on the pipeline section connected with the vacuum pipeline of the freezing chamber, the sublimation drying chamber, the buffer chamber, the resolution drying chamber and the discharge buffer chamber.

[0008] The conveying belt in the freezing chamber, the sublimation drying chamber, the buffer chamber, the resolution drying chamber and the discharge buffer chamber is disconnected at the sealing door of the chamber connection.

[0009] The feeding end of the drying box is provided with a feeding conveying belt for conveying the placing rack into the drying box, and the discharging end of the drying box is provided with a discharging conveying belt for conveying the placing rack after the freeze-drying treatment.

[0010] After the above structure, the material containing moisture is placed on the placing rack and pre-delivered to the feeding conveyor belt. The sealing door of the drying box feeding end is opened, the feeding conveyor belt and the freezing chamber conveyor belt are simultaneously driven, the placing rack is sent to the conveyor belt in the freezing chamber, the sealing door of the drying box feeding end is closed, the heat pump evaporator, heat pump compressor and heat pump condenser are started to run, and the sealing doors between the chambers in the drying box are closed. The gas in the freezing chamber circulates between the freezing chamber and the heat pump evaporator through the cold air circulation pipeline. The heat pump evaporator absorbs the heat in the freezing chamber to reduce the temperature in the freezing chamber, and then the moisture in the material on the placing rack is frozen into ice crystals. The heat pump compressor pumps the heat absorbed by the heat pump evaporator into the heat pump condenser. After the material on the placing rack is frozen and formed, the first vacuum pump is started to perform vacuumizing operation on the freezing chamber and the sublimation drying chamber. After the vacuum degree reaches the set value, the sealing door between the freezing chamber and the sublimation drying chamber is opened. The conveyor belt in the freezing chamber and the conveyor belt in the sublimation drying chamber are simultaneously operated. The placing rack in the freezing chamber is sent to the conveyor belt in the sublimation drying chamber. The sealing door between the freezing chamber and the sublimation drying chamber is closed. The water in the second condenser hot water circulation pipe flows between the sublimation drying chamber and the heat pump condenser to heat and warm the material on the placing rack in the sublimation drying chamber. In the vacuum negative pressure environment, the ice crystals in the material can accelerate sublimation and evaporation. The evaporated water is discharged through the vacuumizing system. Most of the moisture in the material is removed in the sublimation drying chamber. Then the automatic pressure regulating valve connected with the buffer chamber is opened. When the vacuum degree of the buffer chamber and the sublimation drying chamber reaches the same value, the sealing door between the sublimation drying chamber and the buffer chamber is opened. One of the placing racks in the sublimation drying chamber is sent to the conveyor belt in the buffer chamber. Then the sealing door between the buffer chamber and the sublimation drying chamber is closed. At this time, the second vacuum pump is pre-started, and the automatic pressure regulating valves connected with the desorption drying chamber and the buffer chamber are opened. The vacuum degree of the desorption drying chamber and the buffer chamber reaches the same value. The sealing door between the buffer chamber and the desorption drying chamber is opened. The placing rack enters the desorption drying chamber, and the sealing door is closed. The material in the desorption drying chamber is improved in vacuum degree and temperature, so that the moisture in the core position of the material is slowly desorbed, and the final drying purpose is achieved.The water in the first condenser hot water circulation pipeline circulates between the desorption drying chamber and the heat pump condenser, the water absorbs the heat in the heat pump condenser to cool the heat pump condenser, the temperature of the water after absorbing the heat is increased, the hot water heats the substances on the placing rack when flowing through the desorption drying chamber, under the heating and negative pressure environment, the remaining small amount of water in the substances is slowly volatilized and removed, after the water in the substances is removed, the automatic pressure regulating valve of the discharging buffer chamber vacuumizing pipeline is opened, the sealing door between the desorption drying chamber and the discharging buffer chamber is opened after the vacuum degrees of the desorption drying chamber and the discharging buffer chamber reach the same, the placing rack in the desorption drying chamber is sent out, then the sealing door between the desorption drying chamber and the discharging buffer chamber is closed, the desorption drying chamber and the external environment are different, the discharging buffer chamber plays a buffering role, at this time, the sealing door of the discharging end of the drying box is opened after the discharging buffer chamber is broken vacuum, the dried placing rack in the discharging buffer chamber is sent to the discharging conveying belt, the phased freeze-drying process is completed, and the freeze-drying process is repeated, the three processes of freeze-drying are carried out in different chambers, the placing rack continuously enters the drying box and is continuously sent out of the drying box, and a continuous production process is formed.

[0011] The drying box of the energy-saving freeze-drying device is provided with a freezing chamber, a sublimation drying chamber, a buffer chamber, a desorption drying chamber and a discharging buffer chamber from the feeding end to the discharging end, each chamber can maintain a negative pressure environment under the action of the vacuum pump, and the water in the substances is removed after being treated by each chamber; the heat pump evaporator absorbs the heat in the freezing chamber, the temperature in the freezing chamber is reduced, the water in the substances is condensed into ice crystals in the freezing chamber, the heat pump compressor pumps the heat absorbed by the heat pump evaporator into the heat pump condenser, the sublimation drying chamber and the desorption drying chamber are connected with the heat pump condenser through the condenser hot water circulation pipeline, and the water is used for heating the sublimation drying chamber and the desorption drying chamber after absorbing the heat in the heat pump condenser, so as to accelerate the volatilization speed of the water, fully recover the heat energy in the freezing chamber, reduce the heating of the sublimation drying chamber and the desorption drying chamber from the external heat source, and save energy consumption; the freezing, sublimation drying and desorption drying of the substances are carried out in three independent chambers, the three processes can be carried out at the same time, so that the placing rack can be continuously sent into the drying box and sent out of the drying box, the drying time is saved, and the production efficiency is improved; the buffer chamber is arranged between the sublimation drying chamber and the desorption drying chamber, the discharging buffer chamber is arranged between the desorption drying chamber and the outside, the placing rack can be stably transmitted between the two chambers, the sublimation drying chamber and the desorption drying chamber can better maintain the negative pressure environment and temperature condition in the chambers, and the removal process of the water is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 A structure schematic view of the present utility model;

[0013] In the drawing: 1, feeding conveyor belt; 2, freezing chamber; 3, sublimation drying chamber; 4, buffer chamber; 5, desorption drying chamber; 6, discharging buffer chamber; 7, discharging conveyor belt; 8, heat pump condenser; 9, heat pump compressor; 10, heat pump evaporator; 11, first condenser hot water circulation pipeline; 12, second condenser hot water circulation pipeline; 13, evaporator cold air circulation pipeline; 14, first vacuum pump; 15, first vacuumizing pipeline; 16, second vacuum pump; 17, second vacuumizing pipeline; 100, placing rack. DETAILED DESCRIPTION

[0014] With reference to Figure 1 An energy-saving vacuum freeze-drying device, comprising a drying box, a vacuumizing system, a heat pump energy recovery system and a conveying system, the drying box is used for freeze-drying treatment of water-containing substances to remove water in the substances, the vacuumizing system makes the drying box in a negative pressure environment to make water evaporate faster, the heat pump energy recovery system heats the frozen substances by using heat in the device, which is beneficial to water evaporation and removal, and the conveying system sends the substances to be freeze-dried into the drying box, transfers the substances in the drying box and sends the dried substances out. Both ends of the drying box are provided with sealing doors, the sealing doors at both ends can isolate the drying box from the outside and are used for the entry and exit of a placing rack 100, the feeding end of the drying box is provided with a feeding conveyor belt 1, the feeding conveyor belt 1 can send the placing rack 100 into the drying box, the discharging end of the drying box is provided with a discharging conveyor belt 7, the discharging conveyor belt 7 can send the freeze-dried placing rack 100 out, and the internal cavity of the drying box is divided into a freezing chamber 2, a sublimation drying chamber 3, a buffer chamber 4, a desorption drying chamber 5 and a discharging buffer chamber 6 in sequence through the sealing doors from the feeding end to the discharging end. Figure 1 As shown in the figure, the sealing doors at the connecting positions of the conveyor belts in the chambers are disconnected, that is, separate conveyor belts are arranged in the chambers, the conveyor belts can be independently operated, after the sealing doors are opened, the placing rack 100 on the conveyor belt in the front chamber can be sent to the conveyor belt in the rear chamber, the placing rack 100 in the present utility model is conveyed from front to rear, two conveyor belts are arranged in the sublimation drying chamber 3 and the desorption drying chamber 5, the conveyor belt close to the feeding sealing door in the sublimation drying chamber 3 and the desorption drying chamber 5 is shorter, and the conveyor belt close to the discharging sealing door is longer, of course, only one conveyor belt can also be arranged.

[0015] With reference to Figure 1, the vacuum system comprises a first vacuum pump 14 and a second vacuum pump 16, the first vacuum pump 14 is connected with the freezing chamber 2, the sublimation drying chamber 3 and the buffer chamber 4 through the first vacuum pipeline 15, the second vacuum pump 16 is connected with the buffer chamber 4, the desorption drying chamber 5 and the discharge buffer chamber 6 through the second vacuum pipeline 17, the first vacuum pump 14 and the second vacuum pump 16 make the five chambers in the drying box in a negative pressure state, and the automatic pressure regulating valve is arranged on the pipe section connected with the vacuum pipeline of the freezing chamber 2, the sublimation drying chamber 3, the buffer chamber 4, the desorption drying chamber 5 and the discharge buffer chamber 6, wherein the automatic pressure regulating valve refers to a power valve different from a manual valve, such as an electric valve, which can remotely control the opening and closing of the valve, and the vacuumization of the chamber is controlled by controlling the opening and closing of the automatic pressure regulating valve.

[0016] With reference to Figure 1 , the heat pump energy recovery system comprises a heat pump evaporator 10, a heat pump compressor 9, a heat pump condenser 8 and connecting pipelines. The freezing chamber 2 is connected with the heat pump evaporator 10 through the evaporator cold air circulation pipeline 13, when the gas in the freezing chamber 2 flows through the heat pump evaporator 10 in the evaporator cold air circulation pipeline 13, the heat pump evaporator 10 absorbs heat, the cooled gas enters the freezing chamber 2 to cool the freezing chamber 2, and then the water contained in the substances on the placing rack 100 in the freezing chamber 2 is frozen into ice crystals, the heat pump evaporator 10 is connected with the heat pump condenser 8 through a pipeline, the heat pump compressor 9 is arranged on the connecting pipeline between the heat pump evaporator 10 and the heat pump condenser 8, the heat pump compressor 9 pumps the heat absorbed by the heat pump evaporator 10 into the heat pump condenser 8, the desorption drying chamber 5 is connected with the heat pump condenser 8 through the first condenser hot water circulation pipeline 11, the sublimation drying chamber 3 is connected with the heat pump condenser 8 through the second condenser hot water circulation pipeline 12, and the desorption drying chamber 5 is connected with the heat pump condenser 8 through the first condenser hot water circulation pipeline 11, the water circulates between the heat pump condenser 8 and the sublimation drying chamber 3 or the desorption drying chamber 5 through the condenser circulation pipeline, the water absorbs heat and rises in temperature when flowing through the heat pump condenser 8, and the heat pump condenser 8 is cooled at the same time, the hot water flows through the sublimation drying chamber 3 and the desorption drying chamber 5 and releases heat, so as to heat the sublimation drying chamber 3 and the desorption drying chamber 5, and then heat the substances on the placing rack 100, accelerate the volatilization and removal of water, and reduce the temperature of the hot water.

[0017] It should be noted that the actual drying box is also provided with a thermometer, a pressure gauge (negative pressure gauge) and other accessories, and the pipeline is provided with a pump, a valve and a detection instrument and other accessories, which are conventional settings in the field and are not shown in the drawings and the text, and will not be described in detail here.

[0018] Working principle: taking food freeze-drying as an example, the food to be freeze-dried is placed on the placing rack 100, the placing rack 100 is placed on the feeding conveying belt 1, the sealing door of the feeding end of the drying box is opened, the feeding conveying belt 1 is driven at the same time as the conveying belt in the freezing chamber 2, the placing rack 100 on the feeding conveying belt 1 is sent to the conveying belt in the freezing chamber 2, the sealing door of the feeding end of the drying box is closed, the sealing doors between the chambers in the drying box are closed, the heat pump evaporator 10, the heat pump compressor 9 and the heat pump condenser 8 are opened, the heat pump evaporator 10 absorbs heat in the freezing chamber 2 through the evaporator cold air circulation pipeline 13, so that the temperature in the freezing chamber 2 is reduced to below-40℃, the heat pump compressor 9 pumps the heat absorbed by the heat pump evaporator 10 into the heat pump condenser 8, the center of the food on the placing rack 100 reaches about-40℃, the moisture forms ice crystals, the first vacuum pump 14 is opened, the freezing chamber 2 and the sublimation drying chamber 3 are vacuumized, when the negative pressure values in the freezing chamber 2 and the sublimation drying chamber 3 reach a certain value and the pressure is consistent, the sealing door between the freezing chamber 2 and the sublimation drying chamber 3 is opened, the conveying belts in the freezing chamber 2 and the sublimation drying chamber 3 are driven at the same time, the placing rack 100 is sent from the conveying belt in the freezing chamber 2 to the conveying belt in the sublimation drying chamber 3, the sealing door between the freezing chamber 2 and the sublimation drying chamber 3 is closed, hot water circulates between the sublimation drying chamber 3 and the heat pump condenser 8 through the second condenser hot water circulation pipeline 12, the temperature of the water rises after absorbing heat from the heat pump condenser 8, the hot water releases heat when passing through the sublimation drying chamber 3, and at the same time, the placing rack 100 is heated, the temperature in the sublimation drying chamber 3 is controlled at-40℃ to 30℃, and the vacuum value in the sublimation drying chamber 3 is controlled at 30-50Pa, under the conditions of negative pressure and heating, the ice crystals formed by the free water in the food on the placing rack 100 evaporate rapidly and are removed, the drying time is about 10-12 hours, about 90% of the free water can be removed, the automatic pressure regulating valve on the connecting pipeline between the first vacuum pump 14 and the buffer chamber 4 is opened, when the negative pressure values in the sublimation drying chamber 3 and the buffer chamber 4 are consistent, the sealing door between the sublimation drying chamber 3 and the buffer chamber 4 is opened, a group of placing racks 100 in the sublimation drying chamber 3 are sent to the conveying belt in the buffer chamber 4, the negative pressure values in the sublimation drying chamber 3 and the buffer chamber 4 are consistent when the placing racks 100 are transferred, so as to avoid affecting the stability of the device when the sealing door is opened due to the different pressures in the two chambers, the fluctuation of the environmental conditions in the sublimation drying chamber 3 is also smaller, which is conducive to maintaining the internal environment, then the sealing door between the sublimation drying chamber 3 and the buffer chamber 4 is closed, the buffer chamber 4 is located between the sublimation drying chamber 3 and the desorption drying chamber 5, the internal negative pressure environment and temperature of the sublimation drying chamber 3 are different from those of the desorption drying chamber 5, the buffer chamber 4 plays a buffering role, which is conducive to maintaining the internal conditions of the sublimation drying chamber 3 and the desorption drying chamber 5.The second vacuum pump 16 is started in advance, and the automatic pressure regulating valve on the pipeline connecting the second vacuum pump 16 and the desorption drying chamber 5 is opened, so that the vacuum degree of the desorption drying chamber 5 is consistent with that of the buffer chamber 4. The sealing door between the buffer chamber 4 and the desorption drying chamber 5 is opened, the placing rack 100 is sent to the conveying belt in the desorption drying chamber 5, and then the sealing door is closed. The vacuum degree and the temperature in the desorption drying chamber 5 are increased, so that the moisture in the internal core position of the material is slowly desorbed, and the final drying purpose is achieved. The hot water circulates between the desorption drying chamber 5 and the heat pump condenser 8 through the hot water circulating pipeline 11 of the first condenser. After the water absorbs the heat of the heat pump condenser 8, the temperature of the water is increased. When the hot water passes through the desorption drying chamber 5, heat is released, and the food on the placing rack 100 is heated. The temperature in the desorption drying chamber 5 is controlled to be 35 DEG C to 60 DEG C, and the vacuum value in the desorption drying chamber 5 is controlled to be 20-30 Pa. The combined water in the food on the placing rack 100 is slowly evaporated and removed. The negative pressure environment and the heating condition can accelerate the volatilization speed of the combined water. The drying time is about 6-8 hours. About 10% of the combined water in the food is removed. At this time, the moisture in the food on the placing rack 100 is almost completely removed. After the moisture in the food is removed, the automatic pressure regulating valve on the vacuum pipeline connecting the second vacuum pump 16 and the discharging buffer chamber 6 is opened. When the vacuum degrees of the discharging buffer chamber 6 and the desorption drying chamber 5 are consistent, the sealing door between the desorption drying chamber 5 and the discharging buffer chamber 6 is opened. The placing rack 100 in the desorption drying chamber 5 is sent to the conveying belt in the discharging buffer chamber 6. Then the sealing door between the desorption drying chamber 5 and the discharging buffer chamber 6 is closed. The desorption drying chamber 5 is different from the external environment, and the discharging buffer chamber 6 plays a buffering role, so that the influence on the inside of the desorption drying chamber 5 during discharging is reduced. Before discharging, the discharging buffer chamber 6 is broken in vacuum. A communication valve can be arranged on the wall of the discharging buffer chamber 6. The communication valve is slowly opened to break the vacuum environment in the discharging buffer chamber 6. Then the sealing door at the discharging end of the drying box is opened. The placing rack 100 is sent to the discharging conveying belt 7 from the discharging buffer chamber 6. The phased freeze-drying process is completed. The three processes of freeze-drying are carried out in different chambers. The placing rack 100 is continuously sent into and out of the drying box, so that a continuous production process is formed, the drying time is saved, and the production efficiency is improved.A buffer chamber 4 is arranged between the sublimation drying chamber 3 and the desorption drying chamber 5, and a discharge buffer chamber 6 is arranged between the desorption drying chamber 5 and the external environment, so that the placing rack 100 is smoothly transferred between different chambers, and the influence on the internal negative pressure environment and temperature of the sublimation drying chamber 3 and the desorption drying chamber 5 when the sealing door is opened is reduced, the internal freeze-drying conditions of the sublimation drying chamber 3 and the desorption drying chamber 5 are beneficial to be maintained, and the freeze-drying process is beneficial to be promoted and energy consumption is saved.

[0019] The energy-saving freeze-drying device fully recovers and utilizes the internal heat energy of the drying box, the heat pump energy recovery system is adopted to transfer the heat energy of the freezing chamber to the sublimation drying chamber and the desorption drying chamber, the sublimation drying chamber and the desorption drying chamber are heated while the temperature of the freezing chamber is reduced, one-stroke two-gets effect is achieved, energy consumption is saved, and the energy-saving freeze-drying device is suitable for dehydration of food, Chinese medicinal materials, biological products, nanometer molecular materials and the like; freezing, sublimation drying and desorption drying are carried out in different chambers, the drying box can continuously operate, freeze-drying time is saved, and production efficiency is improved.

Claims

1. An energy-saving vacuum freeze-drying device, comprising a drying chamber connected to a vacuum system via a pipe, wherein both the inlet and outlet ends of the drying chamber are equipped with sealed doors, characterized in that: The internal cavity of the drying box is divided into a freezing chamber (2), a sublimation drying chamber (3), a buffer chamber (4), a desorption drying chamber (5), and a discharge buffer chamber (6) in sequence from the feeding end to the discharging end through a sealing door, and a conveying belt for conveying the placing rack (100) from the feeding end to the discharging end is arranged in each chamber, the freezing chamber (2) is connected with a heat pump evaporator (10) through an evaporator cold air circulation pipeline (13), the desorption drying chamber (5) is connected with a heat pump condenser (8) through a first condenser hot water circulation pipeline (11), the sublimation drying chamber (3) is connected with the heat pump condenser (8) through a second condenser hot water circulation pipeline (12), the heat pump evaporator (10) and the heat pump condenser (8) are connected through a pipeline, and a heat pump compressor (9) is arranged on the connecting pipeline between the heat pump evaporator (10) and the heat pump condenser (8).

2. The energy efficient vacuum freeze-drying apparatus as claimed in claim 1, wherein: The vacuum pumping system comprises a first vacuum pump (14) and a second vacuum pump (16), the first vacuum pump (14) is connected with the freezing chamber (2), the sublimation drying chamber (3), and the buffer chamber (4) through a first vacuum pumping pipeline (15), and the second vacuum pump (16) is connected with the buffer chamber (4), the desorption drying chamber (5), and the discharge buffer chamber (6) through a second vacuum pumping pipeline (17).

3. The energy efficient vacuum freeze-drying apparatus as claimed in claim 2, wherein: An automatic pressure regulating valve is arranged on the pipeline section connected with the vacuum pumping pipeline in each of the freezing chamber (2), the sublimation drying chamber (3), the buffer chamber (4), the desorption drying chamber (5), and the discharge buffer chamber (6).

4. The energy efficient vacuum freeze-drying apparatus as claimed in claim 1, wherein: The conveying belt in each of the freezing chamber (2), the sublimation drying chamber (3), the buffer chamber (4), the desorption drying chamber (5), and the discharge buffer chamber (6) is disconnected by the sealing door at the connection between chambers.

5. The energy efficient vacuum freeze-drying apparatus as claimed in claim 1, wherein: The feeding end of the drying box is provided with a feeding conveying belt (1) for feeding the placing rack (100) into the drying box, and the discharging end of the drying box is provided with a discharging conveying belt (7) for discharging the placing rack (100) after the freeze-drying treatment.

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