Drying system and drying method

Abstract

To provide a drying system and a drying method capable of shortening a drying time.SOLUTION: A drying system 1 includes a vessel body 21 for storing a frozen object F consisting of a plurality of treated material lumps F1 obtained by freezing a treated material, a heating medium temperature adjustment unit 3 and stirring means 22 for drying the frozen object F by sublimating a solidified liquid component contained in the frozen object F stored in the vessel body 21, imaging means 24 for taking an image of a range including the frozen object F stored in the vessel body 21, and control means 7 for adjusting a drying speed by the heating medium temperature adjustment unit 3 and the stirring means 22 on the basis of a state of the frozen object F in the image taken by the imaging means 24.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a drying system and a drying method for drying a frozen material by sublimating a solidified liquid component contained in the frozen material. [Background technology]

[0002] Vacuum freeze-drying technology is known, in which materials (hereinafter referred to as the "subject") used in foods, cosmetics, medical products, raw materials for electronic components, chemical products, paints, etc. are frozen to produce a frozen product, and the solidified liquid components contained in the frozen product are sublimated to produce a dried product. A representative system using this vacuum freeze-drying technology is a shelf-type drying system. A shelf-type drying system is an apparatus in which shelves for placing frozen products are provided in a vacuum chamber, and the temperature of the shelves is adjusted to an appropriate level under reduced pressure to dry the frozen product while it remains frozen, producing a dried product.

[0003] In a shelf-type drying system, the material to be processed is placed on a tray, which is then placed on a shelf and frozen to obtain a frozen product. After that, the pressure inside the device is reduced to sublimate the solidified liquid components contained in the frozen product. At that time, the shelf on which the tray is placed is heated to supply heat to the frozen product to promote drying. However, if the product is heated too much, the solidified liquid components contained in the frozen product melt and lumps (aggregations of the product to be processed) form in the dried product, resulting in a decrease in quality. Therefore, the amount of heat supplied to the frozen product by heating is set to a level that compensates for the heat taken away by sublimation. In addition, when the dried product is dispersed in liquid again, good restorability (water reconstitution) is required so that the product can be restored to the same state as before drying. However, if lumps form, the restorability (water reconstitution) is impaired. Furthermore, in a shelf-type drying system, the frozen product in the tray basically receives heat only from the bottom side where the shelf is located, so the part of the frozen product that receives heat is always the same part, and that part is prone to melting. Even if only the bottom surface of the frozen material melts, a small amount of lumps will be mixed into the dried product, lowering the quality of the dried product. For this reason, it becomes necessary to reduce the amount of heat supplied (heating temperature) and heat the frozen material while maintaining its frozen state, so a shelf-type drying system requires a long time until the material dries. The shelf-type drying system described here can be said to be a static drying system in which the frozen material does not move.

[0004] On the other hand, a drying system has been proposed in which a frozen material consisting of many blocks of material is obtained by freezing the material to be processed, and the frozen material is then dried while being moved (see, for example, Patent Document 1). The drying in this drying system can be said to be dynamic drying. In this drying system, the frozen material is dried while being moved, so heat can be applied evenly to the surface of the frozen material, and therefore a larger amount of heat can be supplied to the frozen material (higher heating temperature) compared to shelf-type drying systems, and the drying time is shortened. In addition, frictional heat is generated between the frozen material by moving it, so the frozen material is heated in areas other than those where heat from the outside is transferred, further shortening the drying time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-72411 Summary of the Invention [Problem to be solved by the invention]

[0006] In the drying system described in Patent Document 1, the drying speed of the frozen material is adjusted by automatically increasing the amount of heat supplied to the frozen material over time using a program. This program needs to be set to a supply amount of heat with a sufficient margin so that the frozen material does not melt. For this reason, if the drying speed is determined by the program and a drying operation is performed, the drying time tends to be longer than necessary. On the other hand, when drying a frozen material to be processed that is being used for the first time, a skilled operator may adjust the drying speed while checking the drying state and melting state of the frozen material during drying. A skilled operator can monitor the drying state and melting state of the frozen material and adjust the frequency of moving the frozen material and the amount of heat supplied to the frozen material to perform a drying operation at a more suitable drying speed. However, even in the drying system that performs dynamic drying described in Patent Document 1, the required drying time is usually long, usually 24 to 60 hours, so it is difficult for an operator to monitor it constantly. When the operator cannot monitor or when it is difficult to judge the drying state and melting state, it is necessary to set the drying speed with a sufficient margin so that the frozen material does not melt. As a result, there is a problem that the drying time is still longer than necessary.

[0007] In view of the above circumstances, an object of the present invention is to provide a drying system and a drying method that can shorten the drying time. [Means for solving the problem]

[0008] The drying system of the present invention which solves the above problems includes: A container body for storing a frozen material consisting of a plurality of processing object blocks obtained by freezing a processing object; a drying means for drying the frozen material stored in the container body by sublimating a solidified liquid component contained in the frozen material; an imaging means for imaging an area including the frozen object stored in the container body; and a control means for adjusting a drying speed by the drying means based on a state of the frozen object in an image captured by the imaging means.

[0009] According to this drying system, the control means adjusts the drying speed to a value suitable for the state of the frozen material, thereby making it possible to shorten the drying time.

[0010] Here, the drying means may photograph an area including the frozen material and a boundary between the frozen material and the inner surface of the container body. The drying means may have a heating means for heating the frozen material, and the control means may adjust the drying speed by adjusting the amount of heat supplied to the frozen material by the heating means. The control means may increase the drying speed according to the progress of drying of the frozen material.

[0011] In this drying system, the photographing means photographs a boundary portion between the frozen object stored in the container body and an inner surface of the container body, The control means may determine a pile height of the frozen material stored in the container body based on an image of the boundary portion, and adjust the drying speed based on the pile height.

[0012] Since the processed material chunks become finer as the drying proceeds, the pile height decreases with the progress of the drying. Therefore, by determining the pile height of the frozen material, the drying status can be grasped, and the frozen material can be dried at a drying speed suitable for the drying status.

[0013] In addition, in this drying system, The control means may determine a size of the mass of the frozen material based on an image of the frozen material obtained by the photographing means, and adjust the drying speed based on the size.

[0014] This also makes it possible to dry the frozen material at the drying speed suited to the drying conditions of the frozen material.

[0015] Furthermore, in this drying system, The control means may create a concentration histogram from the image of the frozen product obtained by the photographing means, and estimate the size of the processed mass based on the distribution of concentrations in the concentration histogram.

[0016] By estimating the size of the processed material lump based on the distribution state of the concentration in the concentration histogram, the size of the processed material lump can be estimated in a wide range.

[0017] In addition, in this drying system, The control means may determine a color tone of the frozen product from an image of the frozen product obtained by the photographing means, and adjust the drying speed based on the color tone.

[0018] This also makes it possible to dry the frozen material at the drying speed suited to the drying conditions of the frozen material.

[0019] In addition, in this drying system, The control means may determine a shape of the mass of the frozen material from an image of the frozen material obtained by the photographing means, and adjust the drying speed based on the shape.

[0020] As the drying process progresses, the corners of the processed material lump are rounded off and the material becomes nearly spherical. Therefore, by determining the shape of the frozen material, the frozen material can be dried at a drying speed appropriate to the drying conditions.

[0021] In addition, in this drying system, A jacket is provided to cover the outer periphery of the container body and to which a heat medium is supplied, The drying means includes a frozen material operating unit that moves the frozen material stored in the container body within the container body, and a heat supply amount adjustment unit that adjusts the amount of heat supplied to the frozen material through the jacket by the heat medium, The control means may adjust the drying speed by adjusting at least one of the speed at which the frozen material is moved, the frequency at which the frozen material is moved, and the amount of heat supplied, based on the state of the frozen material photographed by the photographing means.

[0022] According to this drying system, the drying speed can be reliably changed.

[0023] Here, the frozen material operating unit may be configured to agitate the frozen material stored in the container body. The frozen material operating unit may be configured to move the frozen material within the container by moving the container body. The heat supply adjustment unit may be configured to adjust the temperature of the heat medium.

[0024] Furthermore, in the drying system, The control means may determine whether or not a gloss is present on the surface of the frozen material from the image of the frozen material obtained by the photographing means, and may reduce the drying speed if a gloss is present on the surface of the frozen material.

[0025] This can prevent the frozen product from forming lumps.

[0026] The drying method of the present invention which solves the above problems includes: A drying method for a drying system including a container body for storing a frozen material obtained by freezing an object to be processed, and a drying means for drying the frozen material by sublimating a solidified liquid component contained in the frozen material stored in the container body, comprising: an imaging step of imaging an area including the frozen object stored in the container body; and a drying speed control step of adjusting the drying speed by the drying means in accordance with the state of the frozen object in the image captured in the photographing step.

[0027] According to this drying method, the drying time can be shortened by adjusting the drying speed to a speed suitable for the state of the frozen material in the drying speed control step. Effect of the Invention

[0028] According to the present invention, it is possible to provide a drying system and a drying method capable of shortening the drying time. [Brief description of the drawings]

[0029] [Figure 1] 1 is a system diagram of a drying system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a control configuration of the drying system shown in FIG. [Diagram 3] 2 is a flowchart showing control in a drying process of the drying system shown in FIG. 1. [Figure 4] 2 is a diagram showing an example of an image obtained by photographing the inside of the container body shown in FIG. 1. [Diagram 5] 4 is a flowchart similar to FIG. 3, showing a first modified example. [Figure 6] FIG. 11 is a diagram showing a method for estimating the size of a frozen object in a second modified example. [Figure 7] 10 is a flowchart similar to FIG. 3, showing a third modified example. [Figure 8] 10 is a flowchart similar to FIG. 3, illustrating a fourth modified example. [Figure 9] 13A and 13B are diagrams illustrating modified examples of the heat medium temperature adjustment unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drying system according to an embodiment of the present invention will now be described in detail with reference to the drawings. The drying system described below is a system for freezing a processing object and drying the frozen object.

[0031] FIG. 1 is a system diagram of a drying system 1 corresponding to one embodiment of the present invention.

[0032] The drying system 1 shown in FIG. 1 includes a drying container 2, a heat medium temperature adjusting section 3, a vacuum pump 4, a cold trap 5, and a refrigerator 6.

[0033] The drying container 2 has a container body 21, a stirring means 22, a jacket 23, an imaging means 24, and lighting 25. Fig. 1 shows a schematic cross section of the container body 21 cut vertically so that the inside of the container body 21 can be seen. Also, in Fig. 1, the frozen object F inside the container body 21 is shown by a dot pattern.

[0034] The container body 21 is supported by a support (not shown). The container body 21 is composed of a cylindrical upper portion 211, an inverted cone-shaped portion 212 that gradually reduces in diameter as it moves away from the upper portion 211, and an upper lid 213 that covers the upper end of the upper portion 211. The container body 21 is also provided with a thermometer 214 that measures the temperature of the stored items such as the brine liquid and frozen items F stored inside, and a brine liquid outlet 215. The thermometer 214 constantly measures the temperature of the stored items. A discharge outlet 2121 is provided at the lower end of the container body 21, i.e., the lower end of the inverted cone-shaped portion 212, and the discharge outlet 2121 is closed by an openable and closable discharge lid 216.

[0035] The upper cover 213 is provided with an inlet 2131, a photographing window 2132, a light window 2133, and an exhaust port 2134. A dispersion liquid in which the material to be treated is dispersed in a liquid is introduced into the container body 21 through the inlet 2131. The dispersion liquid is then frozen while being stirred in the container body 21, and a frozen material F consisting of a number of processed material chunks F1 (see FIG. 4) is generated. Note that a brine liquid is stored in the container body 21 before the dispersion liquid is introduced, and the dispersion liquid is frozen in the brine liquid, and then only the brine liquid is drained from the brine liquid outlet 215, so that the frozen processed material chunks F1 remain in the container body 21. However, the frozen material F may be prepared by another device, and introduced into the empty container body 21 through the inlet 2131 and stored in the container body 21. Also, the material to be treated containing a liquid component may be directly frozen in the container body 21 without using a dispersion liquid to produce the frozen material F. Furthermore, the object to be processed containing a liquid component may be directly frozen in another device without using a dispersion liquid to prepare a frozen object F, which may then be introduced into the empty container body 21 through the introduction port 2131 and stored in the container body 21. In this embodiment, ethanol is used as the brine liquid, but instead of ethanol, organic compounds such as paraffins, alicyclic hydrocarbons, alcohols, and ethers having a melting point of −30° C. or lower and a boiling point of less than 100° C. may be used.

[0036] The photographing window 2132 is made of transparent glass. The photographing means 24 photographs the state inside the container body 21 through the photographing window 2132. The photographing means 24 may photograph a still image, may photograph a video, or may photograph both a still image and a video. The photographing means 24 may photograph continuously or at a predetermined time interval, and may photograph a still image or a video in response to a request from the control means 7 (see FIG. 2) described later. Furthermore, the photographing means 24, the photographing window 2132, the lighting 25, and the light window 2133 may be provided in a plurality of sets as necessary. In this embodiment, an example in which a still image is photographed in response to a request from the control means 7 will be described. The photographing means 24 is capable of photographing an area including the entire inner surface of the inverted cone-shaped portion 212 and the discharge port 2121 from the upper end of the container body 21. That is, when there is a frozen object F stored in the container body 21, the photographing means 24 is capable of photographing an area including at least the frozen object F.

[0037] The light window 2133 is also made of transparent quartz glass. The light emitted by the lighting 25 illuminates the inner surface of the inverted cone-shaped portion 212 and the frozen object F inside the container body 21 through the light window 2133. This makes the image obtained by the imaging means 24 clear.

[0038] The exhaust port 2134 is for discharging gases such as air in the container body 21 and water vapor generated in the container body 21. The exhaust port 2134 is connected to an exhaust path 51 via an exhaust filter (not shown). Gas that has passed through the exhaust filter enters the exhaust path 51. A cold trap 5 is provided in the middle of the exhaust path 51, and a vacuum pump 4 is provided downstream of the cold trap 5.

[0039] The stirring means 22 has a rotating spiral ribbon 221, a stirring drive shaft 222, and a stirring drive device 223. This stirring means 22 corresponds to an example of a frozen material operating unit. The spiral ribbon 221 is entirely made of metal, is supported by a plurality of rod-shaped support members protruding radially from the stirring drive shaft 222, and travels around the inner surface of the container body 21 in the vicinity of the inner surface of the container body 21. The spiral ribbon 221 may be made of resin such as engineering plastics or fiber-reinforced plastics. The spiral ribbon 221 has a spiral shape that tapers downward. This spiral ribbon 221 rotates when the stirring drive shaft 222 rotates around its axis. The stirring drive shaft 222 penetrates the upper cover 213. The penetration portion of the stirring drive shaft 222 penetrating the upper cover 213 is sealed. The stirring drive device 223 is a motor that rotates the stirring drive shaft 222. The agitation drive shaft 222 is driven by the agitation drive device 223 to rotate about its axis, thereby rotating the spiral ribbon 221. The rotation of the spiral ribbon 221 generates a circulatory flow of the frozen material F stored in the container body 21. That is, the rotation of the spiral ribbon 221 causes the frozen material F located near the inner surface of the container body 21 to be lifted upward, and the frozen material located in the center of the container body 21 in a plan view to move downward. This causes the frozen material F stored in the container body 21 to be agitated. By increasing the number of rotations of the spiral ribbon 221, the frozen material F is lifted further upward, and the flow speed of the frozen material F in the circulatory flow increases, so that the frozen material F is moved at a faster speed.

[0040] The jacket 23 covers the outer periphery of the container body 21. A heat medium supply path 231 and a heat medium recovery path 232 are connected to the jacket 23. The heat medium supply path 231 has a leading end connected to the lower part of the jacket 23 and a rear end connected to the heat medium temperature adjustment unit 3. On the other hand, the heat medium recovery path 232 has a leading end connected to the heat medium temperature adjustment unit 3 and a rear end connected to the upper part of the jacket 23.

[0041] The heat medium temperature adjustment unit 3 has a heat medium pump 31, a check valve 32, a first flow rate adjustment valve 33, a second flow rate adjustment valve 34, a heat medium cooler 35, a heat medium heater 36, and a heat medium tank 37. The heat medium temperature adjustment unit 3 corresponds to an example of a supply heat amount adjustment unit. The heat medium heater 36 corresponds to an example of a heating means. The heat medium pump 31 delivers a liquid heat medium at a set flow rate. The heat medium is ethanol, which is the same as the above-mentioned brine liquid. Of course, the heat medium may be other than ethanol, and may be different from the brine liquid. The delivered heat medium passes through the check valve 32 and is divided into the heat medium cooler 35 and the heat medium heater 36 at the divided flow rates set by the first flow rate adjustment valve 33 and the second flow rate adjustment valve 34, respectively. That is, the heat medium delivered from the heat medium pump 31 flows to the heat medium cooler 35 and the heat medium heater 36 at a ratio according to the opening degrees of the first flow rate control valve 33 and the second flow rate control valve 34. The first flow rate control valve 33 and the second flow rate control valve 34 can each set the flow rate to zero, so that the heat medium can flow to only one of the heat medium cooler 35 and the heat medium heater 36. The control means 7 (see FIG. 2), which will be described later, adjusts the flow rate delivered by the heat medium pump 31, the opening degree of the first flow rate control valve 33, and the opening degree of the second flow rate control valve 34 so that the flow rate of the heat medium heading toward the heat medium heater 36 is always constant.

[0042] The heat medium cooler 35 cools the heat medium passing through it, but can also pass the heat medium as it is without cooling it. The heat medium that has passed through this heat medium cooler 35 flows toward the heat medium tank 37. The heat medium tank 37 stores the heat medium returned from the jacket 23 and the heat medium that has passed through the heat medium cooler 35. The heat medium stored in the heat medium tank 37 is sent out by the heat medium pump 31 at a set flow rate. The heat medium heater 36 heats the heat medium that has passed through it, but can also pass the heat medium as it is without heating it. The heat medium that has passed through this heat medium heater 36 flows toward the jacket 23 through the heat medium supply path 231.

[0043] The heat medium temperature adjustment unit 3 circulates the heat medium, the temperature of which has been adjusted to a set temperature by the heat medium cooler 35 and the heat medium heater 36, between the jacket 23. That is, the heat medium is repeatedly circulated, such as being supplied to the jacket 23 through the heat medium supply path 231, and then being returned from the jacket 23 to the heat medium temperature adjustment unit 3 through the heat medium recovery path 232. By circulating and supplying the heat medium to the jacket 23, the temperature of the container body 21 can be adjusted from the outside, and the temperature inside can be adjusted to a desired temperature. That is, the heat medium temperature adjustment unit 3 adjusts the amount of heat supplied to the frozen object F stored in the container body 21 through the jacket 23. The heat medium temperature adjustment unit 3 can adjust both the temperature and flow rate of the heat medium, and can adjust the amount of heat supplied to the frozen object F in the container body 21 by either of these. However, in this embodiment, an example will be described in which the flow rate of the heat medium supplied to the jacket 23 is controlled to be constant, and the amount of heat supplied to the frozen object F in the container body 21 is adjusted by adjusting the temperature of the heat medium. The heat medium temperature adjusting unit 3 mainly supplies heat to the frozen object F, but can also be used to cool the brine in the container body 21, as will be described in detail later.

[0044] The vacuum pump 4 reduces the pressure inside the container body 21. The vacuum pump 4 is provided at the downstream end of the flow of gas that has passed through the exhaust port 2134. The vacuum pump 4, the heat medium temperature adjustment unit 3, and the stirring means 22 together correspond to an example of a drying means. By driving the vacuum pump 4, gases such as air in the container body 21 and water vapor generated in the container body 21 are drawn toward the vacuum pump 4. Then, the gases that reach the vacuum pump 4 are exhausted to the outside of the vacuum pump 4.

[0045] As described above, the cold trap 5 is disposed in the middle of the exhaust path 51. A refrigerant is circulated and supplied from the refrigerator 6 to the cold trap 5, and most of the liquid components such as moisture contained in the gas passing through the cold trap 5 are solidified after sublimation (solidification) or condensation, and adhere to a cooling pipe (not shown) provided in the cold trap 5.

[0046] FIG. 2 is a block diagram showing a control configuration of the drying system 1 shown in FIG.

[0047] As shown in FIG. 2, the control means 7 includes an image processing unit 71, a control unit 72, and a storage unit 73. The control means 7 is a PLC (Programmable Logic Controller). Instead of or in addition to the PLC, another computer may be used as the control means 7. The image processing unit 71 can cut out an arbitrary range from the image captured by the image capturing unit 24 and perform image processing. The image processing unit 71 performs image conversion such as monochrome conversion, gloss extraction, color tone judgment, shape judgment, and the like. The image processing unit 71 also judges the state of the frozen object F based on the image. This judgment of the frozen object F will be described in detail later. The control unit 72 controls each of the controlled components, such as the heat medium pump 31, the first flow rate control valve 33, the second flow rate control valve 34, the heat medium cooler 35, the heat medium heater 36, and the agitation drive device 223, which are provided in the drying system 1. The storage unit 73 is composed of a volatile memory and a non-volatile memory. This memory unit 73 stores a program describing the control operation of each controlled object component by the control unit 72, as well as images obtained by the photographing means 24 and information on the frozen object F processed by the image processing unit 71.

[0048] Next, a description will be given of a drying method for obtaining a dried material by drying the frozen material F using the drying system 1 shown in Fig. 1. The processing in this drying method is executed by the control means 7 controlling each controlled object configuration.

[0049] In this drying system 1, a frozen material F is produced as a preparation step before starting the drying process. In producing the frozen material F, a brine liquid is supplied to the empty container body 21 from the inlet 2131 provided on the upper cover 213. Then, the container body 21 is sealed, and the temperature of the brine liquid is measured by the thermometer 214 while the heat medium temperature adjusting unit 3 cools the heat medium to a desired cooling temperature (for example, -30°C) that is lower than the freezing point of the dispersion liquid. In parallel, the refrigerator 6 is operated to lower the temperature of the cold trap 5 to -40°C. When the brine liquid reaches the desired cooling temperature, the dispersion liquid is put into the container body 21 and rapidly frozen by immersion in the brine, thereby producing a frozen material F in which the dispersion liquid is frozen. In this embodiment, an example is described in which a dispersion liquid using water as a liquid component is used, but a dispersion liquid using a liquid component other than water may be used. In addition, a plurality of processed material chunks F1 that are pre-frozen in advance and crushed to at least a degree that can pass through the inlet 2131 may be used as the frozen material F. When the brine liquid is cooled or the dispersion liquid is frozen, the stirring means 22 is driven to rotate the spiral ribbon 221. As a result, the dispersion liquid dropped into the brine liquid becomes a frozen material F consisting of a number of treated material chunks F1 (see FIG. 4) of a certain size. When the frozen material F is obtained, only the brine liquid is drained from the brine liquid outlet 215 provided in the container body 21. As a result, the treated material chunks F1 remain in the container body 21. Thereafter, the control means 7 controls the temperature of the heat medium to −20° C., which is a temperature below the eutectic point of the frozen material F. The control means 7 also controls the spiral ribbon 221 to rotate at 10 revolutions per minute. The rotation speed of the spiral ribbon 221 is preferably 10 revolutions per minute or more and 15 revolutions per minute or less. The rotation speed set in this preparation process becomes the minimum rotation speed in the drying process. The temperature, rotation speed, or intermittent stirring time distribution in the case of intermittent stirring is set by the operator selecting a value that does not reliably melt the frozen material F according to the type of material to be processed, the type of liquid component of the dispersion, or the proportions of the container body 21, and inputting it into the control means 7, and can be changed as appropriate by the operator. Also, by using a means that can automatically recognize the input conditions, it is possible to perform the preparation process automatically. By performing the above preparation process, preparation for starting the drying process is completed.Note that the method of producing frozen material F using a brine solution is merely one example. There are various other pre-freezing methods, such as a freezing method in which a dispersion liquid is sprayed under vacuum, and a freezing method in which the jacket 23 is heated to approximately 0°C to make the inside of the container body 21 less than 600 PaA and self-freeze, and any of these methods may be used to produce frozen material F.

[0050] FIG. 3 is a flowchart showing control in the drying process of the drying system 1 shown in FIG.

[0051] When the drying process is started, the control means 7 drives the vacuum pump 4 while maintaining the temperature of the heat medium, the temperature in the cold trap 5, and the rotation speed of the spiral ribbon 221 at the values ​​set in the preparation process. The pressure in the container body 21 is reduced to about 13 Pa or more and 120 Pa or less by driving the vacuum pump 4. During the drying process, the control means 7 maintains the pressure in the container body 21 at about 13 Pa or more and 120 Pa or less. When the pressure in the container body 21 decreases to about 13 Pa or more and 120 Pa or less, for example, about 110 Pa, and further receives frictional heat from the spiral ribbon 221 and the container body 21, the moisture in the solidified frozen object F sublimes and begins to generate water vapor. Most of the generated steam is captured by the cold trap 5 on the way to the vacuum pump 4 through the exhaust path 51 and becomes ice. In addition, there may be a small amount of brine liquid remaining in the container body 21 that was not completely drained during the preparation process. In such a case, the gas generated in the container body 21 may contain evaporated brine liquid, but this is an extremely small amount and usually does not pose a problem.

[0052] The control means 7 periodically repeats the processing of steps S10 to S23 shown in FIG. 3 at a predetermined time interval (for example, 10-minute interval) until the drying process is completed. Hereinafter, each of these periodically repeated processes may be referred to as a periodic process. The control means 7 obtains temperature data of the frozen object F at the start of each periodic process from the thermometer 214. The control means 7 also obtains an image captured by requesting the image capturing means 24 to capture an image at the start of the periodic process (step S10). In this step S10, the process in which the image capturing means 24 captures an image of an area including the frozen object F corresponds to an example of the image capturing process. In addition, when capturing an image, the stirring may be temporarily slowed down or stopped in order to improve the resolution of the still image. Next, the control means 7 determines whether the temperature of the frozen object F obtained from the thermometer 214 is equal to or lower than a reference temperature (step S11). The reference temperature is the temperature (eutectic point) at which the frozen object F begins to melt under the pressure inside the container body 21 or a temperature slightly lower than that temperature. This reference temperature is, for example, -15°C at the beginning of the drying process, and is gradually increased (raised) to a final temperature of 20°C according to the previous pile height stored in the storage unit 73 described later.

[0053] If the temperature of the frozen object F is equal to or lower than the reference temperature (YES in step S11), the control means 7 judges whether or not melting has occurred on the surface of the frozen object F based on the image acquired from the photographing means 24 (step S12). Specifically, the image processing unit 71 processes the image to judge whether or not gloss has occurred on the surface of the frozen object F, and if gloss has occurred, it is judged that melting has occurred, and if gloss has not occurred, it is judged that melting has not occurred.

[0054] If no melting occurs on the surface of the frozen material F (YES in step S12), the control means 7 judges whether or not the pile height of the frozen material F in the container body 21 obtained by the image acquired from the photographing means 24 is less than the previous pile height stored in the memory unit 73 (step S13). The pile height of the frozen material F is high at the beginning of the drying process when the processed material lumps F1 are large and there are large gaps between the processed material lumps F1, and decreases as the drying progresses and the processed material lumps F1 become smaller, thereby reducing the gaps between the processed material lumps F1. Therefore, the gradual decrease in the pile height indicates that the drying process is progressing smoothly. The pile height is equal to the pile amount (volume) of the frozen material F including the gaps between the processed material lumps F1, so the pile height can be said to be synonymous with the pile amount of the frozen material F including the gaps. A specific method for determining this pile height will be described with reference to FIG. 4. Note that in the first regular process, the information on the previous pile height is not stored in the memory unit 73, so this step S13 becomes NO.

[0055] Fig. 4 is a diagram showing an example of an image captured inside the container body 21 shown in Fig. 1. Fig. 4(a) is a diagram explaining a first method for determining the pile height of the frozen material F, and Fig. 4(b) is a diagram explaining a second method for determining the pile height of the frozen material F. The pile height of the frozen material F can be measured by using either the first method or the second method. Note that the spiral ribbon 221 and the stirring drive shaft 222 are omitted in Fig. 4.

[0056] As shown in FIG. 4(a), the photographing means 24 photographs the inner surface of the upper part of the inverted cone-shaped portion 212 and the frozen material F accumulated in the lower part of the inverted cone-shaped portion 212. Since the frozen material F is piled up to a height below the upper end of the inverted cone-shaped portion 212 of the container body 21, the entire upper surface of the frozen material F stored in the container body 21 is photographed by the photographing means 24 together with the upper part of the inverted cone-shaped portion 212. In the first method for determining the piled up height of the frozen material F, the image processing unit 71 processes the image and extracts the boundary part between the inner surface of the container body 21 and the frozen material F in the container body 21. At this time, the image processing unit 71 selects and extracts the range in which the spiral ribbon 221 is not reflected. Note that the processed material mass F1 is white or light gray, and the gaps between the processed material masses F1 are black on the image, so that the inner surface of the container body 21 and the upper surface of the spiral ribbon 221 are preferably a color other than white, black, and gray so as to be distinguishable from these. In this embodiment, the container body 21 and the spiral ribbon 221 are made of stainless steel and are silver in color. The inner surface of the container body 21 and the upper surface of the spiral ribbon 221 may be painted or colored in a color other than white, black, or gray. The inner surface of the container body 21 and the upper surface of the spiral ribbon 221 may be different in color. In FIG. 4(a), the boundary portion to be extracted is shown surrounded by a two-dot chain rectangle. As the pile height of the frozen material F decreases, the curvature of the arc shape formed by the inner surface of the inverted cone-shaped portion 212 and the boundary line of the frozen material F increases. Since the relationship of the curvature of the inverted cone-shaped portion 212 in a plan view to the height from the bottom of the inverted cone-shaped portion 212 is known, the pile height of the frozen material F can be obtained by calculating the curvature from the arc shape of the boundary portion.

[0057] As shown in FIG. 4(b), in the second method of calculating the pile height of the frozen material F, the image processor 71 processes the image and extracts the boundary between the inner surface of the container body 21 and the frozen material F in the container body 21 so that two boundary parts appear within a square. At this time, the image processor 71 selects and extracts an area in which the spiral ribbon 221 is not reflected. In FIG. 4(b), the part to be extracted is shown surrounded by a two-dot chain rectangle. If the shortest distance L1 from the center position to the extraction position in a plan view of the inverted cone-shaped portion 212 is constant, the distance L2 between the two boundary parts becomes shorter as the pile height of the frozen material F decreases. Therefore, the pile height of the frozen material F can be calculated from the relationship between the shortest distance L1 from the center position to the extraction position in a plan view of the inverted cone-shaped portion 212 and the distance L2 between the two boundary parts. Alternatively, although not shown, the amount of accumulation and the accumulation height at a corresponding position may be indicated on the inner surface of the container body 21 by painting, coloring, or engraving, and an image of a number indicating the accumulation height may be recognized as the amount of accumulation by the image processing unit 71. In particular, when the container body 21 has a simple cylindrical shape, the accumulation height can be found by applying an indication indicating the accumulation height to the inner surface of the cylinder and recognizing the indication by image processing.

[0058] 3, if the pile height obtained from the image acquired in the current periodic processing is less than the previous pile height (YES in step S13), the control means 7 judges whether the temperature of the heat medium supplied to the jacket 23 is less than the maximum temperature (step S14). This maximum temperature is, for example, 20° C. The maximum temperature is set by the operator by selecting it according to the type of the workpiece and the type of liquid component of the dispersion and inputting it into the control means 7, and can be changed as appropriate by the operator. On the other hand, if the pile height is equal to or greater than the previous pile height (NO in step S13), the process proceeds to step S18.

[0059] If the temperature of the heat medium supplied to the jacket 23 is less than the maximum temperature (YES in step S14), the temperature of the heat medium supplied to the jacket 23 is increased by 3°C (step S15). That is, if it is determined in step S13 from the image captured by the image capture means 24 that the drying of the frozen material F is progressing smoothly based on the pile height of the frozen material F and in step S14 that there is still room for increasing the temperature of the heat medium, the temperature of the heat medium is increased to increase the drying speed of the frozen material F. The temperature to be increased is set by the operator by selecting it and inputting it into the control means 7, and can be changed appropriately by the operator, but is preferably 3°C or more and 10°C or less. Note that if the temperature of the heat medium exceeds the maximum temperature by increasing the temperature by 3°C, the temperature of the heat medium is increased only up to the maximum temperature. In addition, if the rotation speed of the spiral ribbon 221 has not reached the maximum rotation speed, the rotation speed of the spiral ribbon 221 may be slightly increased by about 4 rotations / min when the temperature of the jacket 23 is increased. This maximum rotation speed is set by the operator to about 4 to 10 times the minimum rotation speed (10 rotations / minute). In this embodiment, it is set to 86 rotations / minute. By increasing the rotation speed of the spiral ribbon 221, the frequency with which the frozen object F is moved within the container body 21 increases, and the frozen object F is lifted higher. By increasing the rotation speed of the spiral ribbon 221, the drying speed of the frozen object F can also be increased.

[0060] When the process of increasing the temperature of the heat medium in step S15 is completed or when the temperature of the heat medium supplied to the jacket 23 is equal to or higher than the maximum temperature (NO in step S14), it is determined whether the pile height of the frozen material F is less than a first predetermined height (step S16). The pile height of the frozen material F is the height obtained from the image in step S13. The first predetermined height is a value set by the operator based on the amount of dispersion liquid poured into the container body 21 and inputting it to the control means 7, and in many cases, a pile height slightly higher than the pile height when the frozen material F becomes a desired dried material state is set. By setting in this manner, it is determined that most of the moisture in the frozen material F has sublimated and disappeared, and the drying process is in the final stage.

[0061] If the rotation speed of the spiral ribbon 221 is increased in the beginning or middle of the drying process, the frozen object F is likely to melt due to frictional heat between the spiral ribbon 221 and the frozen object F, frictional heat between the frozen objects F, and frictional heat between the frozen object F and the inner surface of the container body 21. However, since the moisture content is reduced at the end of the drying process, the risk of melting is reduced even if the rotation speed of the spiral ribbon 221 is increased. For this reason, it is preferable to increase the rotation speed of the spiral ribbon 221 to increase the drying speed, since the drying time and the energy consumption related to drying can be reduced. In addition, since the frozen object F is lifted higher by increasing the rotation speed of the spiral ribbon 221, the frozen object F and the inner surface of the container body 21 come into contact with each other even in the upper part of the container body 21, and the heat of the heat medium can be efficiently transferred to the frozen object F. Therefore, if the pile height of the frozen object F is less than the first predetermined height (YES in step S16), the rotation speed of the spiral ribbon 221, i.e., the stirring rotation speed of the frozen object F is increased to the maximum rotation speed (86 rotations / min) to increase the drying speed (step S17). On the other hand, if the pile height of the frozen material F is equal to or greater than the predetermined value (NO in step S16), the drying process is still in the early or middle stage, so step S17 is not executed and the process proceeds to step S18 so that the frozen material F does not melt.

[0062] If the temperature of the frozen material F exceeds the reference temperature in step S11 described above (NO in step S11) and if melting occurs on the surface of the frozen material F in step S12 described above (NO in step S12), the frozen material F is in a state where it may melt if left as is. Therefore, the control means 7 sets the temperature of the heat medium supplied to the jacket 23 to a lowering temperature below the eutectic point of the frozen material F (step S21). This reduces the drying speed of the frozen material F, and suppresses melting of the frozen material F. This lowering temperature is, for example, -5°C. The lowering temperature is set by the operator selecting it according to the type of the object to be treated and the type of liquid component of the dispersion liquid, and inputting it into the control means 7, and can be changed as appropriate by the operator.

[0063] Following the start of the temperature change of the heat medium in step S21, the control means 7 judges whether the rotation speed of the spiral ribbon 221 exceeds a predetermined rotation speed (step S22). This predetermined rotation speed is set to 10 rotations / min, which is the minimum rotation speed. However, this predetermined rotation speed can be changed appropriately by the operator. If the rotation speed of the spiral ribbon 221 exceeds the predetermined rotation speed (YES in step S22), the control means 7 reduces the rotation speed of the spiral ribbon 221 to the minimum rotation speed (step S23). This also reduces the drying speed of the frozen object F, and suppresses melting of the frozen object F. When the process of step S23 is completed or the rotation speed of the spiral ribbon 221 does not exceed the predetermined rotation speed (NO in step S22), the process proceeds to step S18. The above-described steps S12 to S17 and steps S21 to S23 executed when NO in step S12 correspond to an example of a drying speed control process.

[0064] In step S18, the information on the pile height of the frozen material F obtained in step S13 is stored in the storage unit 73. Here, when step S18 is executed via steps S21 to S23, there is no pile height information of the frozen material F in the current periodic processing, so the information on the previous pile height is stored in the storage unit 73 as the current pile height information. When step S18 is executed via steps S21 to S23, the pile height of the frozen material F may be measured as in step S13 and stored in the storage unit 73 as the current pile height information. After that, the control means 7 judges whether a predetermined time has elapsed since the start of the current periodic processing (step S19). Then, it waits until the predetermined time has elapsed (NO in step S19). This predetermined time is 10 minutes, which is the time interval of the periodic processing. Note that the predetermined time in step S19 can be changed appropriately by the operator, and the time interval of the periodic processing can be changed arbitrarily by changing this predetermined time.

[0065] After a predetermined time has elapsed (YES in step S19), it is determined whether the pile height of the frozen material F is less than a second predetermined height and the size of the largest one of the processed material blocks F1 is equal to or smaller than the size of the processed material block F1 in the desired dried material (step S20) based on the image of the frozen material F obtained in step S10 and the information on the pile height of the frozen material F obtained in step S13. This second predetermined height is a value set by an operator, selected based on the amount of dispersion liquid poured into the container body 21, and input to the control means 7. In step S20, instead of the pile height of the frozen material F and the size of the processed material block F1, it may be determined whether the pressure in the container body 21 and the temperature in the cold trap 5 are both constant, which is generally performed as a conventional determination of the end of the drying process. In addition, in step S20, it may be determined based on only one of the pile height of the frozen material F and the size of the processed material block F1. If the pile height of the frozen material F is less than the second predetermined height and the size of the processed material block F1 is equal to or smaller than the desired size of the dried material (YES in step S20), the drying process is terminated since the drying is complete. On the other hand, if the pile height of the frozen material F is equal to or larger than the second predetermined height or the size of the processed material block F1 exceeds the desired size of the dried material (NO in step S20), the process returns to step S10 and starts the next periodic process.

[0066] According to the drying system 1 and the drying method of this embodiment, the control means 7 adjusts the temperature of the heat medium supplied to the jacket 23 and / or the rotation speed of the spiral ribbon 221 based on the state of the frozen material F, such as the pile height and melting, obtained from the image of the frozen material F photographed by the photographing means 24, to increase or decrease the drying speed of the frozen material F within a range in which the frozen material F does not melt, so that the optimal drying conditions can be created even if the operator is not monitoring the drying system 1. This reduces the burden on the operator and improves the quality of the dried material obtained from the frozen material F because the frozen material F can be dried under optimal drying conditions. Furthermore, the drying speed is basically automatically increased within a range in which there is no risk of melting based on the state of the frozen material F, so that the drying time can be shortened. In particular, the drying speed of the frozen material F is increased according to the pile height of the frozen material F, so that the frozen material can be dried at a drying speed suitable for the progress of the drying process. In addition, the drying speed of the frozen material F is adjusted by changing both or one of the temperature of the heat medium and the rotation speed of the spiral ribbon 221, so that the drying speed of the frozen material F can be reliably changed. Furthermore, the gloss of the surface of the frozen material F that occurs in the early stages of the frozen material F starting to melt is judged from an image of the frozen material F, and the drying speed is slowed down when gloss is present, thereby preventing the frozen material F from melting and forming lumps.

[0067] Next, a modified example of this embodiment will be described. In the following description, components having the same names as components described above will be assigned the same reference numerals as those used above, and duplicate descriptions will be omitted.

[0068] FIG. 5 is a flow chart similar to FIG. 3, showing a first modified example.

[0069] The drying system 1 and the drying method of the first modified example are different from the previous embodiment in that, as shown in FIG. 5, the size of the processed material block F1 is determined instead of determining the pile height of the frozen material F. In step S131 instead of step S13, the control means 7 measures the size of the processed material block F1 from the image obtained from the photographing means 24, and determines whether the size of the processed material block F1 is smaller than the size of the processed material block F1 in the previous regular processing stored in the memory unit 73. If the measured size of the processed material block F1 is smaller than the size of the previous processed material block F1, it can be determined that the drying is proceeding smoothly. The size of the processed material block F1 in the determination in step S131 and step S161 described later and the size of the processed material block F1 stored in step S181 described later are the size of the largest of the processed material blocks F1. The size of the processed material block F1 is calculated by extracting the outline of each processed material block F1 from the image and calculating the area enclosed by the outline.

[0070] In step S161, which replaces step S16, the control means 7 judges whether the size of the processed material block F1 is less than a first predetermined value. The size of the processed material block F1 is the size obtained from the image in step S131. This first predetermined value is a value selected by the operator based on the size of the processed material block F1 in the desired dried material and set by inputting it into the control means 7, and in many cases a value slightly larger than the desired size of the processed material block F1 is set. By setting it in this manner, it is judged that most of the moisture in the frozen material F has disappeared and the drying process is nearing the end.

[0071] In step S181 instead of step S18, the control means 7 stores size information of the processed material block F1 obtained in step S131 in the memory unit 73. Here, when step S181 is executed via steps S21 to S23, there is no size information of the processed material block F1 in the current periodic processing, so the previous size information is stored as the current size information in the memory unit 73. Note that when step S18 is executed via steps S21 to S23, the size of the processed material block F1 may be measured as in step S131 and stored in the memory unit 73 as the current size information.

[0072] In step S20, the control means 7 measures the pile height of the frozen material F in a manner similar to that described in step S13, and then determines whether the pile height of the frozen material F is less than a second predetermined height and whether the size of the processed material block F1 obtained in step S131 is equal to or smaller than the size of the processed material block F1 in the desired dried material.

[0073] The drying system 1 and the drying method of the first modified example described above also have the same effects as those of the previous embodiment.

[0074] FIG. 6 is a diagram showing a method for estimating the size of the frozen object F in the second modified example. FIG. 6(a1) shows an image of a part of the frozen object F cut out at the beginning of the drying process, FIG. 6(b1) shows an image of a part of the frozen object F cut out at the middle of the drying process, and FIG. 6(c1) shows an image of a part of the frozen object F cut out at the end of the drying process. In these FIG. 6(a1), FIG. 6(b1), and FIG. 6(c1), the processed object blocks F1 are shown in a dot pattern. Also, the gaps between the processed object blocks F1 are shown in black. Most of the actual processed object blocks F1 are white or light gray, and the gaps are in shadow, so they appear black in the image.

[0075] FIG. 6(a2) shows a density histogram created by the image processing unit 71 based on the image of the frozen object F in FIG. 6(a1), FIG. 6(b2) shows a density histogram created by the image processing unit 71 based on the image of the frozen object F in FIG. 6(b1), and FIG. 6(c2) shows a density histogram created by the image processing unit 71 based on the image of the frozen object F in FIG. 6(c1). In these density histograms, the horizontal axis is the density value, and the right side in FIG. 6 is closer to black, and the left side is closer to white. The vertical axis in the density histogram is the number (frequency of occurrence), and the higher in FIG. 6, the greater the number. Note that this density histogram shows the distribution of the density of each pixel in the image of the frozen object F, with the number of pixels belonging to each density being the number.

[0076] The drying system 1 and the drying method of the second modified example differ from the drying system 1 and the drying method of the first modified example only in the method of calculating the size of the processed material block F1 in step S131. In the first modified example, the size of the processed material block F1 is measured directly, but in the second modified example, the size of the processed material block F1 is indirectly estimated from the density histogram shown in FIG. 6. In the early stage of the drying process, the processed material block F1 has many gaps between the processed material blocks F1 because each processed material block F1 is large, and the contrast between white and black is clear. For this reason, as shown in FIG. 6(b1), the density histogram has a large number of pieces on the white side and the black side, and a mountain shape is formed on each of the white side and the black side in a steep shape. In contrast, in the middle stage of the drying process, as shown in FIG. 6(b2), the number of pieces near the peaks of the mountains on each of the white side and the black side of the density histogram decreases, the concentration is somewhat averaged, and the valley part (minimum value) between the two mountain shapes moves to the black side. Furthermore, as the drying progresses and the drying process reaches its end, the number of particles on the white and black sides decreases while the amount of gray in between increases, as shown in Figure 6(c2). Compared to the beginning and middle stages of the drying process, the minimum value of the density histogram approaches even blacker and the line showing the density histogram approaches a straight line.

[0077] In the second modified example, the size of the processed product lump F1 is estimated using the change in the density histogram. In step S131, it is determined that the processed product lump F1 has become smaller because the density value of the minimum value in the density histogram has become closer to black than the previous time. In step S161, it is determined whether the processed product lump F1 has become smaller than the first predetermined value depending on whether the minimum value has moved toward the black side from the first density value previously stored in the storage unit 73. Similarly, in step S20, it is determined whether the size of the processed product lump F1 is equal to or smaller than the size of the processed product lump F1 in the desired dried product depending on whether the minimum value has moved toward the black side from the second density value previously stored in the storage unit 73. Note that instead of the density value moving toward the black side, it may be determined by the decrease in the difference between the maximum number and the minimum number in the density histogram.

[0078] The drying system 1 and the drying method of the second modified example have the same effects as those of the previous embodiment. Also, the drying speed of the frozen material F can be adjusted according to the average size of the multiple processing material chunks F1.

[0079] FIG. 7 is a flow chart similar to FIG. 3, showing a third modified example.

[0080] The drying system 1 and drying method of the third modified example differ from the previous embodiment in that, as shown in Fig. 7, the color tone of the frozen material F is determined instead of determining the pile height of the frozen material F. In step S132 instead of step S13, the control means 7 determines, from the image obtained from the photographing means 24, whether or not the area of ​​medium brightness in the color tone of the frozen material F has increased compared to the color tone in the previous image of the frozen material F stored in the storage unit 73. If drying is proceeding smoothly, the areas of high brightness and low brightness will decrease and the area of ​​medium brightness will increase.

[0081] In step S162 instead of step S16, the control means 7 judges whether the area ratio of medium brightness of the frozen object F is equal to or greater than a first predetermined ratio. The first predetermined ratio is judged by comparing with a first reference image stored in the storage unit 73. The first reference image is an image taken at the end of the drying process and stored in the storage unit 73 in advance by the operator.

[0082] In step S182 instead of step S18, the control means 7 causes the storage unit 73 to store the image acquired in step S10.

[0083] In step S202, which replaces step S20, the control means 7 judges whether the area ratio of medium brightness in the frozen material F is equal to or greater than a second predetermined ratio and the size of the largest one of the processed material chunks F1 is equal to or smaller than the size of the desired dried material. The second predetermined ratio is judged by comparison with a second reference image stored in the memory unit 73. The second reference image is an image at the time when the drying process is completed, which is stored in the memory unit 73 in advance by the operator.

[0084] The drying system 1 and the drying method of the third modified example described above also have the same effects as those of the previous embodiment.

[0085] FIG. 8 is a flow chart similar to FIG. 3, showing a fourth modified example.

[0086] The drying system 1 and drying method of the fourth modified example differ from the previous embodiment in that, as shown in Fig. 8, the shape of the frozen material F is determined instead of determining the pile height of the frozen material F. In step S133 instead of step S13, the control means 7 determines from the image obtained from the photographing means 24 whether the shape of the frozen material F has rounded off and is approaching a circle compared to the shape of the frozen material F in the previous image stored in the memory unit 73. If drying is progressing smoothly, the frozen material F will gradually approach a circle. The shape of the processed material block F1 is determined by extracting the outline of each processed material block F1 from the image and using the outline as the shape of the processed material block F1.

[0087] In step S163 instead of step S16, the control means 7 judges whether or not the corners of the frozen object F are almost completely removed. Whether or not the corners are almost completely removed is judged by comparing with a first reference image stored in the memory unit 73. The first reference image is an image taken when the drying process is nearing the end, which is stored in the memory unit 73 in advance by the operator. This first reference image is the same as that used in step S162 of the third modified example.

[0088] In step S183 instead of step S18, the control means 7 causes the storage unit 73 to store the image acquired in step S10.

[0089] In step S203, which replaces step S20, the control means 7 judges whether the shape of the frozen material F is circular and the size of the largest one of the processed material chunks F1 is equal to or smaller than the size of the desired dried material. Whether the shape of the frozen material F is circular is judged by comparing it with a second reference image stored in the memory unit 73. The second reference image is an image at the time when the drying process is completed, which is stored in the memory unit 73 in advance by the operator. This second reference image is the same as that used in step S202 of the third modified example.

[0090] The drying system 1 and the drying method of the fourth modified example described above also have the same effects as those of the previous embodiment.

[0091] Figure 9 is a diagram showing modified examples of the heat medium temperature adjustment section 3. Figure 9(a) is a diagram showing a first modified example of the heat medium temperature adjustment section 3, and Figure 9(b) is a diagram showing a second modified example of the heat medium temperature adjustment section 3.

[0092] As shown in FIG. 9(a), the first modified example of the heat medium temperature adjustment unit 3 differs from the previous embodiment in that the heat medium that has passed through the heat medium cooler 35 is supplied to the jacket 23 through the heat medium supply path 231 without returning to the heat medium tank 37.

[0093] In the first modified example of the heat medium temperature adjustment unit 3, when it is desired to cool the heat medium, the first flow rate adjustment valve 33 is opened and the second flow rate adjustment valve 34 is closed to pass the heat medium cooler 35, and when it is desired to heat the heat medium, the first flow rate adjustment valve 33 is closed and the second flow rate adjustment valve 34 is opened to pass the heat medium heater 36 and send it to the heat medium supply path 231. The openings of the first flow rate adjustment valve 33 and the second flow rate adjustment valve 34 may be adjusted to mix the heated heat medium and the cooled heat medium and send it to the heat medium supply path 231. When neither cooling nor heating is required, at least one of the first flow rate adjustment valve 33 and the second flow rate adjustment valve 34 is opened to pass the heat medium through both the heat medium cooler 35 and the heat medium heater 36 without being cooled or heated, and send it to the heat medium supply path 231.

[0094] As shown in FIG. 9(b), the second modified example of the heat medium temperature regulator 3 differs from the previous embodiment in that the heat medium cooler 35 and the heat medium heater 36 are arranged in series. A first bypass 351 is formed through which the heat medium flows bypassing the heat medium cooler 35, and a third flow control valve 331 is provided in the first bypass 351. Similarly, a second bypass 361 is formed through which the heat medium flows bypassing the heat medium heater 36, and a fourth flow control valve 341 is provided in the second bypass 361. The opening degree of the third flow control valve 331 and the opening degree of the fourth flow control valve 341 are controlled by the control means 7 (see FIG. 2). The opening degree of the third flow control valve 331 and the fourth flow control valve 341 can also be set to zero.

[0095] In the second modified example of the heat medium temperature adjustment unit 3, when it is desired to cool the heat medium, the first flow rate adjustment valve 33 and the fourth flow rate adjustment valve 341 are opened, and the second flow rate adjustment valve 34 and the third flow rate adjustment valve 331 are closed to pass the heat medium only through the heat medium cooler 35. When it is desired to heat the heat medium, the first flow rate adjustment valve 33 and the fourth flow rate adjustment valve 341 are closed, and the second flow rate adjustment valve 34 and the third flow rate adjustment valve 331 are opened to pass the heat medium only through the heat medium heater 36. The openings of the first flow rate adjustment valve 33, the second flow rate adjustment valve 34, the third flow rate adjustment valve 331, and the fourth flow rate adjustment valve 341 may be adjusted to mix the heated heat medium and the cooled heat medium and send them to the heat medium supply path 231. In addition, when neither cooling nor heating is required, the first flow control valve 33 and the second flow control valve 34 are closed, and the third flow control valve 331 and the fourth flow control valve 341 are opened to send the heat medium to the heat medium supply path 231 without cooling or heating.

[0096] The drying system 1 and the drying method using the first modified example of the heat medium temperature adjustment unit 3 and the second modified example of the heat medium temperature adjustment unit 3 also achieve the same effects as those of the previous embodiment.

[0097] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the claims. For example, in the above-mentioned embodiment, the drying speed of the frozen material F is adjusted by adjusting the temperature of the heat medium supplied to the jacket 23 and the rotation speed of the spiral ribbon 221, but only one of these may be adjusted and the other may be kept constant. In addition, the spiral ribbon 221 is always rotating, but it may be configured to rotate and stop repeatedly, and the frequency of moving the frozen material F, which is the ratio of the driving time and the driving stop time of the stirring means 22, may be adjusted, or both the rotation speed and the frequency of moving the frozen material F may be adjusted. Furthermore, instead of adjusting the temperature of the heat medium supplied to the jacket 23, or in addition to adjusting the temperature of the heat medium, the flow rate of the heat medium supplied to the jacket 23 may be adjusted. Furthermore, instead of the spiral ribbon 221, a stirring blade consisting of a blade-shaped paddle member having a flat surface in the vertical direction at the tip part of a metal arm radially protruding from the stirring drive shaft 222 may be provided in the container body 21 to move the frozen material F.

[0098] In addition, instead of the stirring means 22, the entire container body 21 may be supported by a tubular shaft so that it can rotate or swing freely, and the container body 21 may be rotated or swinged by a motor, so that the frozen object F is moved within the container body 21. In such a configuration, the shaft supporting the container body 21, the container body 21, and the motor rotating or swinging the container body 21 correspond to an example of a frozen object operating unit. In that case, instead of adjusting the number of rotations of the spiral ribbon 221, it is preferable to adjust the frequency of rotation or swing of the container body 21. However, the number of rotations or swing of the container body 21 may be adjusted by controlling the container body 21 to always rotate or swing.

[0099] In addition, even if a constituent element is included only in the description of the embodiment and each modified example described above, that constituent element may be applied to the embodiment and each modified example. [Explanation of symbols]

[0100] 1 Drying System 3 Heat medium temperature adjustment section 7 Control Means 21 Container body 22 Stirring means 24 Filming Method F Frozen material F1 Processing material block

Claims

1. A container body for storing a frozen material consisting of a plurality of processing object blocks obtained by freezing a processing object; a drying means for drying the frozen material stored in the container body by sublimating a solidified liquid component contained in the frozen material; an imaging means for imaging an area including the frozen object stored in the container body; and a control means for adjusting a drying speed by the drying means based on a state of the frozen object in an image captured by the imaging means.

2. the photographing means photographs a boundary portion between the frozen object stored in the container body and an inner surface of the container body, The drying system according to claim 1, wherein the control means determines a pile height of the frozen material stored in the container body based on an image of the boundary portion, and adjusts the drying speed based on the pile height.

3. The drying system according to claim 1, wherein the control means determines the size of the mass of the frozen material based on the image of the frozen material obtained by the photographing means, and adjusts the drying speed based on the size.

4. The drying system according to claim 3, characterized in that the control means creates a concentration histogram from the image of the frozen material obtained by the photographing means and estimates the size of the processed material mass based on the concentration distribution in the concentration histogram.

5. 2. The drying system according to claim 1, wherein the control means determines a color tone of the frozen product from the image of the frozen product obtained by the photographing means, and adjusts the drying speed based on the color tone.

6. 2. The drying system according to claim 1, wherein the control means determines a shape of the mass of the frozen material from the image of the frozen material obtained by the photographing means, and adjusts the drying speed based on the shape.

7. A jacket is provided to cover the outer periphery of the container body and to which a heat medium is supplied, The drying means includes a frozen material operating unit that moves the frozen material stored in the container body within the container body, and a heat supply amount adjustment unit that adjusts the amount of heat supplied to the frozen material through the jacket by the heat medium, The drying system according to any one of claims 1 to 6, characterized in that the control means adjusts the drying speed by adjusting at least one of the frequency of moving the frozen material, the speed of moving the frozen material, and the amount of heat supplied, based on the state of the frozen material photographed by the photographing means.

8. The drying system according to any one of claims 1 to 6, characterized in that the control means determines whether or not a gloss is present on the surface of the frozen material from the image of the frozen material obtained by the photographing means, and reduces the drying speed if such gloss is present.

9. A drying method for a drying system including a container body for storing a frozen material obtained by freezing an object to be processed, and a drying means for drying the frozen material by sublimating a solidified liquid component contained in the frozen material stored in the container body, comprising: an imaging step of imaging an area including the frozen object stored in the container body; and a drying speed control step of adjusting the drying speed by the drying means in accordance with the state of the frozen object in the image captured in the photographing step.

Images