KR20200013868A - Vacuum-freeze drying system using heat storage - Google Patents

Abstract

A vacuum freeze drying system using heat storage according to the present invention includes a drying chamber, a vacuum forming unit, a cold trap, a first compressor, a cascade heat exchanger, a first expander, a second compressor, a heat storage tank, a second expander, and a heat transfer unit. A frozen object to be dried in the drying chamber can be dried by sublimation. Particularly, waste heat absorbed by the cold trap is regenerated in the cascade heat exchanger, is stored in the heat storage tank, and then, is supplied as heat energy needed for drying through the heat transfer unit.

Description

Vacuum-freeze drying system using heat storage}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum freeze-drying system, and particularly, when a frozen product is dried by a sublimation phenomenon, vacuum freezing using heat storage capable of regenerating and regenerating waste heat absorbed by a cold trap and supplying it with heat energy required for drying. It relates to a drying system.

Vacuum freeze drying is a method of drying a dry matter by removing water contained in the dry matter by using a sublimation phenomenon. In other words, after freezing the dry matter below the freezing point, the internal pressure of the drying chamber in which the frozen dry matter is stored is lowered below the triple point of water to create a vacuum state, and when the internal temperature of the drying chamber is raised, Sublimation phenomenon occurs when the phase of water is directly transferred to water vapor.

Such a vacuum freeze drying method may be widely used in various fields as a drying method of agricultural products, processed foods, drugs, blood, cells and the like. For example, various agricultural products can be easily and easily decayed by the growth of microorganisms, which can be prevented by a drying method. Among these, the natural drying method is very limited by the temporal, spatial and climatic conditions. On the other hand, the vibration freeze drying method has a large number of advantages, such as high productivity and high quality, as well as preservation of agricultural and aquatic products because a large amount of agricultural and marine products can be dried quickly and uniformly.

Conventional technology regarding such a vacuum freeze drying apparatus is disclosed in Korean Patent Application Publication No. 10-2015-0001315 (published date; 2015.01.06.) By-product vacuum freeze drying apparatus. Looking at the disclosed prior art, the vacuum freeze drying apparatus includes a hermetically sealed chamber into which the frozen by-products of the frozen aquatic product are introduced into a drying material, a vacuum forming unit connected to the chamber and exhausting air in the chamber, and It consists of a heating unit for raising the temperature, a dehumidifying unit for reducing the humidity inside the chamber, a hot plate installed in the chamber, and a boiler for supplying a heat conducting fluid heated by the hot plate to generate heat. The dehumidifier is composed of a cold trap, a cooler, and a defroster that absorbs heat from the water vapor of the chamber.

However, the vacuum freeze drying apparatus according to the prior art does not store the heat absorbed by the cold trap, but just discards it as waste heat, and uses low energy efficiency because it uses a separate energy source boiler or electric heater to heat the hot plate in the chamber. There is a problem of environmental pollution due to waste heat.

Republic of Korea Patent Publication No. 10-2015-0001315

The present invention has been made in order to solve the above problems, an object of the present invention is to provide a vacuum freeze drying system using heat storage that can be supplied to the heat energy required for drying, regenerating and regenerated waste heat absorbed in the cold trap.

In the vacuum freeze-drying system using the heat storage according to the present invention for realizing the above object, the frozen dry matter is accommodated, the drying chamber is evaporated by the sublimation of the moisture of the frozen dry matter when heat is supplied in a vacuum state Wow; A vacuum forming unit connected to the drying chamber to make the drying chamber in a vacuum state; A cold trap connected to the drying chamber to collect moisture evaporated in the drying chamber, and formed by condensation of the evaporated water by an evaporation action of a first refrigerant; A first compressor for compressing the evaporated first refrigerant; A condenser for condensing the compressed first refrigerant; A cascade heat exchanger in which the first refrigerant is radiated by the heat exchange between the condensed first refrigerant and the second refrigerant, and the second refrigerant is evaporated; A first expander installed between the cascade heat exchanger and the cold trap to expand a first refrigerant circulating; A second compressor for compressing a second refrigerant evaporated by accumulating in the cascade heat exchanger; A heat storage tank in which heat of the compressed second refrigerant is dissipated by heat radiation; A second expander installed between the heat storage tank and the cascade heat exchanger to expand a second refrigerant circulating; And a heat transfer part configured to transfer heat to the sublimation action in the drying chamber by the heat accumulated in the heat storage tank.

The circulation cycle of the second refrigerant may be configured such that the second refrigerant radiated from the heat storage tank may be condensed with the first refrigerant in the condenser and then circulated to the second expander.

The heat storage tank includes a phase change material for heat storage; The heat transfer unit is a brine pump installed on a brine pipe to circulate the brine between the heat storage tank and the drying chamber, and is installed inside the heat storage tank to transfer heat from the phase change material to brine. It may include a heat exchange coil in communication with the pipe.

In the defrosting operation of the cold trap, the first refrigerant is compressed in the first compressor, condensed in the cold trap to defrost water vapor condensed on the cold trap, expanded in the defrost expander, and the heat storage tank. It is made of a circulation process evaporated by the heat accumulated by the heat storage tank in the installed defrost evaporator; A first bypass pipe connecting the outlet side of the first compressor and the inlet side of the cold trap so that the first refrigerant compressed by the first compressor can directly bypass the cold trap, and the first bypass pipe The first drying for the first defrost electromagnetic valve installed on the first bypass pipe and the first refrigerant compressed by the first compressor to be circulated to the cascade heat exchanger side during the drying operation to open only during the defrost operation. A second bypass pipe installed to circulate to the inlet of the first compressor and the first electronic condenser, the first refrigerant condensed in the cold trap, and then bypass the defrost expander and the defrost evaporator in turn; The second defrost electronic valve installed on the second bypass pipe so that the bypass pipe is opened only during the defrosting operation, and the first refrigerant evaporated from the cold trap during the drying operation. It may further include a second drying electronic valve to be circulated to the inlet side of the first compressor.

The heater may further include a heater installed in the heat storage tank to accumulate the heat storage tank during an initial drying operation or during the defrosting operation.

Vacuum freeze-drying system using heat storage according to the present invention, the heat absorbed from the cold trap without waste heat is regenerated and regenerated in the heat storage tank, and can be supplied with the heat energy required for drying energy efficiency can be improved It can save energy and prevent environmental destruction by waste heat.

In addition, since the present invention can uniformly supply the energy required for drying by the heat storage method, high quality of the dried product can be ensured.

In addition, the present invention can improve the overall thermal efficiency by condensing the first refrigerant and the second refrigerant in two stages, and can also share the condenser of the first refrigerant and the second refrigerant can simplify the structure.

In addition, the present invention can further install the heater in the heat storage tank to supplement the heat storage in the heat storage tank during the initial drying operation or defrosting operation to reduce the start-up time, it is possible to proceed efficiently defrosting operation.

1 is a configuration diagram showing a refrigerant circulation state during a drying operation as a vacuum freeze drying system using heat storage according to an embodiment of the present invention,
FIG. 2 is a diagram illustrating a refrigerant circulation state during defrost operation of the system illustrated in FIG. 1.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 and 2, a vacuum freeze drying system using heat storage according to the present invention includes a drying chamber 10, a vacuum forming unit 20, a heat transfer unit 30, and a cold trap 50. And a two-way refrigeration cycle unit including a heat storage tank (60).

The drying chamber 10 has a frozen space in which the frozen dry matter is received and has an inner space that can be opened and closed by a door. The drying chamber 10 may have any structure as long as the structure is easy to vacuum and easy to block heat to the outside so that the moisture of the frozen dry matter may be evaporated when heat is supplied in the vacuum state. A steam outlet may be formed at an upper portion of the drying chamber 10 so that evaporated water, that is, water vapor, may be easily moved to the cold trap 50 and may be collected. In the steam pipe 12 connecting the steam outlet of the drying chamber 10 and the cold trap 50, the evaporated water is moved in one direction toward the cold trap 50 from the drying chamber 10, and is transferred to the drying chamber 10. The check valve 14 may be installed to prevent backflow.

The vacuum forming unit 20 is to lower the pressure of the internal space of the drying chamber 10 below the triple point of water for a smooth sublimation action. The vacuum forming unit 20 may include a vacuum pump 22 capable of reducing the internal pressure of the drying chamber 10 by exhausting the internal air of the drying chamber 10 as shown. The vacuum pump 22 may be directly connected to the drying chamber 10, but as shown, the cold trap 50 and the exhaust pipe may be vacuumed together with the cold trap 50 spatially connected to the drying chamber 10. 24 can be connected. The exhaust pipe 24 may be connected to the upper portion of the cold trap 50 for easy exhaust.

The heat transfer part 30 heats up the heat stored in the heat storage tank 60 by the two-way refrigeration cycle unit to increase the internal space temperature of the drying chamber 10 so that the above-described sublimation action can be performed smoothly. To pass on. In particular, the heat transfer unit 30 may be configured to transfer heat stored in the heat storage tank 60 by using brine. The heat transfer unit 30 using brine includes a brine pump 34 installed on the brine pipe 32 piped so that the heat transfer medium can circulate the heat storage tank 60 and the drying chamber 10, and the volume of the heat transfer medium. It may include a brine expansion tank 36 connected to one side of the brine pipe 32 to absorb the change. In addition, as described later, when the heat storage tank 60 accumulates using the phase change material, the heat transfer part 30 communicates with the brine pipe 32 so that the brine passes through, and heat exchange between the brine and the phase change material is possible. A heat exchange coil 38 that may be installed in the heat storage tank 60 may be further included. When the heat is supplied in an indirect manner by using the phase change material as described above, the heat can be uniformly supplied to the drying chamber 10 in a state in which heat is sufficiently stored in the heat storage tank 60, and thus the drying chamber 10. The temperature inside the drying chamber 10 can be easily maintained within the range necessary for the sublimation phenomenon and the temperature of the drying chamber 10 can be kept constant without a sudden temperature change in the drying chamber 10.

The binary refrigeration cycle unit is a circulation cycle in which heat exchange is effected in the order of compression-> condensation-> expansion-> evaporation. In particular, the cold trap 50 is operated by the circulation cycle of the first refrigerant and the circulation cycle of the second refrigerant. By operating the heat storage tank 60 by, the first refrigerant and the second refrigerant is characterized in that the mutual heat exchange. At this time, the type of temperature of the first refrigerant and the second refrigerant when the heat exchange between the first refrigerant and the second refrigerant is determined so that the heat transfer from the first refrigerant to the second refrigerant during the mutual heat exchange action of the first refrigerant and the second refrigerant.

This two-way refrigeration cycle unit includes a cold trap 50, a heat storage tank 60, a cascade heat exchanger 80, and also includes a first compressor 70, a first expander 90, It may be configured to include a second compressor 100, a second expander 110, and a condenser 120.

The cold trap 50 collects moisture (steam) evaporated by the sublimation action in the drying chamber 10, and condenses and vaporizes the vapor collected by the evaporation action of the first refrigerant. To this end, the cold trap 50 may include a cold chamber 52 and a cold trap pipe 54. The cold chamber 52 has an internal space in which the cold trap pipe 54 is accommodated, and the steam pipe 12 and the exhaust pipe 24 are connected to the upper part, respectively, and are vacuumed together with the drying chamber 10 by the vacuum pump 22. The water vapor may be collected from the drying chamber 10 and implanted. The cold trap pipe 54 is configured such that the evaporation action of the circulation cycle of the first refrigerant can be achieved. The temperature of the first refrigerant flowing into the cold trap pipe 54 is set in a range capable of condensing the water vapor collected in the cold chamber 52. That is, by the heat exchange action of the first refrigerant and water vapor, the water vapor is deprived of heat and condenses to the frost in the cold trap pipe 54, and the first refrigerant may be evaporated by taking the heat of the water vapor. Meanwhile, the solenoid valve 56 for drain may be installed at the lower portion of the cold chamber 52 so that the condensed water generated in the cold chamber 52 may be discharged to the outside.

Inside the heat storage tank 60, a phase change material (PCM) which may be phase changed by heat exchange with the second refrigerant and brine may be embedded. Therefore, when the high temperature heat of the second refrigerant is radiated to the heat storage tank 60, the phase change material may be elevated in temperature by heat radiated from the second refrigerant to be phase-changed from solid or liquid to liquid or gaseous phase. The heat storage action of the heat storage tank 60 may be performed by the phase change of the phase change material. When the low temperature heat transfer medium of the heat transfer unit 30 is circulated through the heat storage tank 60, heat transfer may be performed from the high temperature phase change material to the heat transfer medium of the heat transfer unit 30. The phase change material may be phase changed to low temperature as it is radiated. That is, the heat storage tank 60 serves as a condenser to dissipate heat of the second refrigerant in the second refrigerant position, and serves as a heater to supply heat in the heat transfer unit 30 position. In addition, a second refrigerant heat exchange coil 62 is installed in the heat storage tank 60 to communicate with the circulation cycle of the second refrigerant so that the second refrigerant can be circulated and the second refrigerant can be heat exchanged with the phase change material. Can be.

The cascade heat exchanger 80 performs mutual heat exchange between the first refrigerant and the second refrigerant such that the first refrigerant condensed in the condenser 120 may be second condensed and the second refrigerant may be evaporated. That is, in the circulation cycle of the first refrigerant, the cascade heat exchanger 80 dissipates the waste heat absorbed by the cold trap 50 by the evaporation action of the second refrigerant for two times to reduce the condensation temperature (pressure) of the first refrigerant. It acts as a secondary condenser that can be lowered to cryogenic temperatures as much as possible. In the circulation cycle of the second refrigerant, the cascade heat exchanger 80 serves as an evaporator to evaporate the second refrigerant by the condensation of the first refrigerant, and furthermore, the waste heat absorbed by the cold trap 50 is regenerated to heat the storage tank. To be thermally stored at (60). The cascade heat exchanger 80 may be any one as long as possible for heat exchange for two-way refrigeration.

The first compressor 70 / the second compressor 100 is compressed to facilitate the liquefaction of the first refrigerant / the second refrigerant, and the first expander 90 / the second expander 110 is the first refrigerant / second refrigerant To the expansion to facilitate evaporation by expansion valves, etc., detailed description of which is well known to those skilled in the art in the field of refrigeration cycles will be omitted. At the inlet side of the first compressor 70 / the second compressor 100, the first liquid separator 72 / the second liquid separator 102 via the first refrigerant / the second refrigerant, respectively, so that only the gaseous refrigerant is introduced therein. It can be installed to catch the liquid refrigerant and pass only the gaseous refrigerant. In addition, a first oil separator 74 and a second oil separator 104 are installed at the outlet side of the first compressor 70 and the second compressor 100 so that oil can be separated from the first refrigerant / second refrigerant in the gas phase. Can be. In addition, the expansion tank 76 may be installed on the side of the first compressor 70 so as to absorb the volume change of the first refrigerant and prevent overflow. One side of the expansion tank 76 communicates between the first liquid separator 72 and the inlet of the first compressor 70, and the other side is between the outlet of the first compressor 70 and the first oil separator 74. Communicating with. In addition, a second refrigerant is temporarily stored between the condenser 120 and the second expander 110 to absorb the change of the second refrigerant amount according to the load variation in the cascade heat exchanger 80 so that smooth operation is possible. The refrigerant receiver 106 may further include.

The condenser 120 may be configured as an outdoor unit in which the condensation action is performed by a heat exchange action at room temperature as shown, and is not limited thereto, and may be configured as another type of condenser as needed. In particular, the circulation cycle of the first refrigerant and the circulation cycle of the second refrigerant may be configured to share the condenser 120 together so that the condensation action of the first refrigerant and the second refrigerant may be performed together. That is, the condenser 120 includes a first condenser pipe 122 through which the first refrigerant circulated from the first compressor 70 to the cascade heat exchanger 80, and a second expander 110 in the heat storage tank 60. Second condensation pipes 124 through the second refrigerant circulated to each other may be configured.

Therefore, the first refrigerant is the first evaporation line 130 and the first compressor 70 connected to the inlet of the first compressor 70 via the first liquid separator 72 starting with the outlet of the cold trap 50. The first compression line 132 connected to the condenser 120 via the first oil separator 74, and the first condensation line connected to the cascade heat exchanger 80 from the condenser 120. 134, a first heat dissipation line 136 connected from the cascade heat exchanger 80 to the first expander 90, and a first expansion connected from the first expander 90 to the inlet of the cold trap 50. Line 138 may be cycled in turn.

The second refrigerant starts in the cascade heat exchanger 80 and then the second liquid separator 102-> second compressor 100-> second oil separator 104-> heat storage tank 60-> condenser 120 )-> Second refrigerant receiver 106-> second expander 110 may be circulated in the order.

In addition, the two-way refrigeration cycle unit may be configured to enable the defrost operation of the cold trap (50). That is, a phenomenon in which water vapor condenses on the surface of the cold trap pipe 54 and the frost is attached is called a drop. When the drop in the cold trap pipe 54 is excessive, heat exchange is hindered and the performance of the cold trap 50 is deteriorated. This adversely affects the drying performance. Therefore, the defrosting operation is a task of melting and removing frost attached to the cold trap 50. The defrosting operation can be performed using the two-way refrigeration cycle unit, and the two-way refrigeration cycle unit includes the defrost evaporator 150, the defrost expander 152, the first and second bypass pipes 160 and 162, and The first and second drying electron valves 170 and 172 and the first and second defrosting electron valves 180 and 182 may be further included.

The defrost evaporator 150 may be installed in the heat storage tank 60 to facilitate the evaporation of the first refrigerant by the heat accumulated in the heat storage tank 60 during the defrost operation.

The defrost inflator 152 may be configured as an expansion valve installed on the first bypass pipe 160 to expand the first refrigerant circulated from the cold trap 50 to the defrost evaporator 150 during the defrosting operation. Can be.

The first bypass pipe 160 is installed so that the first refrigerant can directly bypass the inlet side of the cold trap 50 starting at the outlet of the first compressor 70. That is, the inlet of the first bypass pipe 160 may be connected to the first compression line 132, and the outlet thereof may be connected to the first expansion line 138. The first defrosting electromagnetic valve 180 may be installed on the first bypass pipe 160 so that the first bypass pipe 160 may be opened only during the defrosting operation. The first drying electromagnetic valve 170 blocks the portion of the first compression line 132 between the connection point of the first bypass pipe 160 and the condenser 120 during the defrosting operation and opens only during the drying operation. 132 may be installed on. Therefore, the first refrigerant compressed by the first compressor 70 is circulated directly to the cascade heat exchanger 80 in the drying operation, and bypassed to the inlet of the cold trap 50 in the defrosting operation.

The second bypass pipe 162 starts at the outlet side of the cold trap 50, passes through the defrost expander 152 and the defrost evaporator 150 in turn, and then enters the first compressor 70. It is installed to bypass the side. That is, the second bypass pipe 162 is connected to the outlet of the first evaporation line 130 near the cold trap 50, and the outlet thereof is the inlet of the first compressor 70 of the first evaporation line 130. Can be connected near the side. The second defrost electromagnetic valve 182 may be installed on the second bypass pipe 162 so that the second bypass pipe 162 may be opened only during the defrosting operation. The second drying electromagnetic valve 172 blocks the portion of the first evaporation line 130 between the outlet of the cold trap 50 and the connection point of the second bypass pipe 162 during the defrosting operation and opens only during the drying operation. It may be installed on the first evaporation line 130. Therefore, in the drying operation, the first refrigerant evaporated in the cold trap 50 is immediately circulated to the inlet side of the first compressor 70, and in the defrosting operation, the first refrigerant condensed in the cold trap 50 passes through the second bypass. Bypass to the inlet side of the first compressor 70 through the pipe (162).

The present invention may further include a heater 190 installed in the heat storage tank 60 to supply thermal energy by an energy source separate from the two-way refrigeration cycle unit. In particular, the heater 190 may be configured in a heat transfer method having a good response and quick response so that the heat required for the heat storage tank 60 can be quickly stored. Accordingly, the heat required for the heat storage tank 60 may be directly stored by the heater 190 until the heat storage by the two-way refrigeration cycle unit reaches the normal level during the initial drying operation. It can be reduced, and the temperature of the drying chamber 10 can be uniformly adjusted from the beginning. In addition, when the heat accumulated in the heat storage tank 60 during the defrost operation is insufficient to evaporate the first refrigerant of the defrost evaporator 150, the heater 190 immediately replenishes the heat required for the defrost evaporator 150. Since the defrosting operation can be made smoothly, it is possible to prevent the first refrigerant of the liquid flows into the first compressor (70).

Meanwhile, the freezing system for freezing the dry matter may be directly configured in the drying chamber 10 or may be configured as a separate system separate from the present invention. In the case of a large amount of drying, it has to be divided into several times and dried. In the former case, freezing and drying in the system of the present invention take a long time to dry one time, leaving the remaining dry items for a long time. In the latter case, the dry items waiting to be dried can be safely stored in a frozen state in advance, and the next volume can be dried immediately after the previous volume is dried, thereby making the overall operation more efficient. In the latter case, the freezing and drying systems are separated so that the whole system can be designed without any complexity.

Referring to the operation of the vacuum freeze drying system using heat storage according to the present invention in detail.

As shown in FIG. 3, in the drying operation, the frozen object is accommodated in the internal space of the drying chamber 10, and the vacuum pump 22 is driven to provide air in the drying chamber 10 and the cold chamber 52. As it is evacuated, the interior of the drying chamber 10 and the cold chamber 52 is frozen below the triple point of water. In addition, the brine pump 34 is driven to transfer heat accumulated in the heat storage tank 60 to the drying chamber 10, and the internal temperature of the drying chamber 10 is increased. Therefore, the water frozen in the dry matter is directly sublimated with water vapor and evaporated into the air in the drying chamber 10 to be removed as the dry matter, and thus the dry matter can be dried. Moisture evaporated in the drying chamber 10 is collected in the cold chamber 52 along the steam pipe (12). In addition, the two-way refrigeration cycle unit is driven so that the water is implanted by the cold chamber 52 and the heat storage by the heat storage tank 60 proceeds together.

Moisture implantation by the cold chamber 52 takes place as follows by the circulation cycle of the first refrigerant.

First, the first drying electron valve 170 and the second drying electron valve 172 are operated so that the first refrigerant can be circulated for the drying operation, the first defrosting electron valve 180 and the second defrosting electron valve 182. ) Is a state in which the first bypass pipe 160 and the second bypass pipe 162 can be blocked so that the first refrigerant is not bypassed to the first bypass pipe 160 and the second bypass pipe 162. It works.

When the first compressor 70 is driven to circulate the cold liquid first refrigerant condensed in the cold trap pipe 54, the heat of the moisture collected in the cold chamber 52 circulates through the cold trap pipe 54. Absorbed by the first refrigerant, water condenses on the pipe surface of the cold chamber 52 to form a frost and is formed to form an evaporation action of the first refrigerant. The evaporated first refrigerant is circulated through the first liquid separator (72) to the first compressor (70), compressed, and then deoiled in the first oil separator (74), and then circulated to the condenser (120) to primary Condensation. The first condensed primary refrigerant is circulated to the cascade heat exchanger (80) to exchange heat with the second refrigerant. In this case, since the first refrigerant absorbs heat from the steam in the cold trap 50 and is relatively high in temperature, and the second refrigerant is in a liquid low temperature state as described below, heat exchange is performed in which waste heat of the first refrigerant is transferred to the second refrigerant. . Accordingly, the first refrigerant may be radiated once more in the cascade heat exchanger 80 to be condensed secondarily. That is, the condensation temperature (or condensation pressure) of the first refrigerant may be lowered as much as possible, and the first refrigerant may be expanded in the first expander 90 and then circulated in the lowest temperature liquid cold trap 50 to be evaporated. Therefore, the evaporation efficiency of the first refrigerant in the cold trap 50 may be improved, and the thermal efficiency of the circulation cycle of the first refrigerant may be improved as a whole.

The heat storage of the heat storage tank 60 is performed as follows by the circulation cycle of the second refrigerant.

The second refrigerant absorbs heat from the first refrigerant by the evaporation action in the cascade heat exchanger 80, and then circulates through the second liquid separator 102 to the second compressor 100 and is compressed. The compressed second refrigerant is circulated to the heat storage tank 60 in an oil separated state via the second oil separator 104. In the heat storage tank 60, heat of the second refrigerant is radiated to the phase change material by the heat exchange effect, so that the heat storage tank 60 may be thermally stored.

The heat dissipated second refrigerant is circulated to the condenser 120, condensed, and then expanded in the second expander 110 via the second refrigerant receiver 106 to be phase-changed to a low-temperature liquid state. May be cycled to 80. In this case, since the second refrigerant may be condensed primarily in the heat storage tank 60 and secondly condensed in the condenser 120, the thermal efficiency of the circulation cycle of the second refrigerant may be improved as a whole.

On the other hand, during the initial drying operation, since the thermal efficiency of the two-way refrigeration cycle unit is low, the amount of heat accumulated in the heat storage tank 60 by the two-way refrigeration cycle unit is small. At this time, the heater 190 is driven together with the two-way refrigeration cycle unit, and thus the heat storage tank 60 can quickly and sufficiently accumulate the heat required for the sublimation action in the drying chamber 10, and thus the drying chamber 10 The internal temperature of c) can be quickly raised and maintained in a range for the sublimation action. When time passes and the normal operation in which the heat storage tank 60 is sufficiently stored even by the two-way refrigeration cycle unit, the heater 190 is not stopped and operated, the heat storage tank 60 only by the two-way refrigeration cycle unit. ) Is accumulated.

As shown in FIG. 2, when the cold trap 50 is excessively loaded during the drying operation, the defrosting operation is performed as follows. Whether or not the defrosting operation may be set according to the dry trapping time of the cold trap 50 such as the elapsed time of the dry operation or the amount of steam in the cold trap 50.

When the defrosting operation is started, a part of the first compression line 132 through which the first refrigerant is circulated from the first compressor 70 to the condenser 120 is blocked by the first drying electronic valve 170, and the second drying application is performed. The first evaporation line 130 through which the first refrigerant is circulated from the cold trap 50 to the first compressor 70 is blocked by the electromagnetic valve 172. On the other hand, the first defrosting electron valve 180 is operated to open the first bypass pipe 160, and the second defrosting electron valve 182 is operated to open the second bypass pipe 162.

When the first compressor 70 is driven in such a state, the compressed high-temperature gas phase first refrigerant is circulated along the first bypass pipe 160 to the cold trap pipe 54, and in the cold trap 50, The frost condensed on the cold trap pipe 54 may be defrosted by the heat of the first refrigerant. The first refrigerant condensed in the cold trap 50 by the defrosting operation is expanded in the defrosting expander 152 along the second bypass pipe 162. The expanded first refrigerant may be evaporated by heat accumulated in the heat storage tank 60 in the defrost evaporator 150 in the heat storage tank 60, and then circulated back to the first compressor 70. At this time, if the heat accumulated in the heat storage tank 60 is insufficient than the heat required for the evaporation action of the first refrigerant circulating the defrost evaporator 150, by driving the heater 190 in the heat storage tank 60 to supplement the heat can do. In the defrosting operation, the heater 190 may be driven when the temperature of the heat storage tank 60 is less than or equal to the temperature range for the defrosting operation so that the temperature of the heat storage tank 60 may be constantly maintained at the defrosting operation temperature range. Accordingly, the first refrigerant may be sufficiently evaporated in the defrost evaporator 150. Therefore, the first refrigerant may be prevented from flowing into the liquid state in the first compressor 70, and the defrosting operation may be smoothly performed without degrading performance.

Meanwhile, as another embodiment of the present invention, the heat storage tank may be heat-generated by using the heat of condensation of the first refrigerant during the initial drying operation as follows.

In other words, during the initial drying operation, the bypass piping and valves can be circulated in the order of the first refrigerant compressed by the first compressor to bypass the heat storage tank and then condenser-> cascade heat exchanger-> first expander-> cold trap. And more. Therefore, during the initial drying operation, the heat of the first refrigerant is radiated to the heat storage tank so that heat storage of the heat storage tank can be made more quickly.

After the heat storage tank is thermally stored above a predetermined level, since the heat storage tank is not heat-generated by the heat of condensation of the first refrigerant, the first refrigerant does not bypass the heat storage tank as described above in an embodiment of the present invention. It may be desirable to have the condenser immediately circulate from the compressor to the condenser.

As described above, the technical idea described in the embodiments of the present invention may be implemented independently, or may be implemented in combination with each other. In addition, the present invention is only the drawings, and those skilled in the art to which the present invention pertains various modifications and equivalent other embodiments from this. Therefore, the technical protection scope of the present invention will be defined by the appended claims.

10; Drying chamber 20; Vacuum forming unit
30; Heat transfer section 50; Cold trap
60; Heat storage tank 70; First compressor
80; Cascade heat exchanger 90; First inflator
100; Second compressor 110; Second expander
120; Condenser 150; Defrost evaporator
152; Defrost inflator 190; heater

Claims (5)

A drying chamber in which the frozen dry matter is accommodated and the heat of the frozen dry matter is sublimed and evaporated when heat is supplied in a vacuum state;
A vacuum forming unit connected to the drying chamber to make the drying chamber in a vacuum state;
A cold trap connected to the drying chamber to collect moisture evaporated in the drying chamber, and formed by condensation of the evaporated water by an evaporation action of a first refrigerant;
A first compressor for compressing the evaporated first refrigerant;
A condenser for condensing the compressed first refrigerant;
A cascade heat exchanger in which the first refrigerant is radiated by the heat exchange between the condensed first refrigerant and the second refrigerant, and the second refrigerant is evaporated;
A first expander installed between the cascade heat exchanger and the cold trap to expand a first refrigerant circulating;
A second compressor for compressing the second refrigerant evaporated in the cascade heat exchanger;
A heat storage tank in which heat of the compressed second refrigerant is dissipated by heat radiation;
A second expander installed between the heat storage tank and the cascade heat exchanger to expand a second refrigerant circulating;
A heat transfer part configured to transfer heat to the sublimation action in the drying chamber by the heat accumulated in the heat storage tank;
Vacuum freeze drying system using a heat storage, characterized in that it comprises a. The method according to claim 1,
The circulation cycle of the second refrigerant is configured to allow the second refrigerant radiated from the heat storage tank to be condensed with the first refrigerant in the condenser and then circulated to the second expander. Vacuum freeze drying system. The method according to claim 1,
The heat storage tank includes a phase change material for heat storage;
The heat transfer part is a brine pump installed on a brine pipe to circulate the brine between the heat storage tank and the drying chamber, and is installed inside the heat storage tank so as to transfer heat from the phase change material to brine. Vacuum freeze drying system using heat storage, characterized in that it comprises a heat exchange coil in communication with the pipe. The method according to claim 1,
In the defrosting operation of the cold trap, the first refrigerant is compressed in the first compressor, condensed in the cold trap to defrost water vapor condensed on the cold trap, expanded in the defrost expander, and the heat storage tank. It is made of a circulation process evaporated by the heat accumulated by the heat storage tank in the installed defrost evaporator;
A first bypass pipe connecting the outlet side of the first compressor and the inlet side of the cold trap so that the first refrigerant compressed by the first compressor can directly bypass the cold trap, and the first bypass pipe The first drying for the first defrost electromagnetic valve installed on the first bypass pipe and the first refrigerant compressed by the first compressor to be circulated to the cascade heat exchanger side during the drying operation to open only during the defrost operation. A second bypass pipe installed to circulate to the inlet of the first compressor and the first electronic condenser, the first refrigerant condensed in the cold trap, and then bypass the defrost expander and the defrost evaporator; The second defrost electronic valve installed on the second bypass pipe so that the bypass pipe is opened only during the defrosting operation, and the first refrigerant evaporated from the cold trap during the drying operation. And a second drying electron valve to be circulated to the inlet side of the first compressor. The method according to claim 4,
And a heater installed in the heat storage tank and configured to accumulate the heat storage tank during an initial drying operation or during the defrosting operation.

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