A freeze-drying method and apparatus

Abstract

The present invention relates to the field of freeze-drying of liquid materials, and discloses a freeze-drying method and device. Among them, the freeze-drying method is used to freeze-dry the materials placed in a heat-conducting container, and includes the following steps: supplying heat to the materials from the top of the materials; when the drying thickness of the materials from top to bottom reaches a preset thickness, supplying heat to the materials from the bottom of the materials. When the drying thickness of the materials from top to bottom reaches the preset thickness, the upper layer of the materials, that is, the part of the materials that has been dried, will preferentially form a water vapor evacuation path. In this way, when the lower layer of the materials, that is, the part of the materials that has not been dried, has a temperature rise and water vapor is generated, it can smoothly sublimate and diffuse from the path formed by the upper layer of the materials, thereby avoiding the accumulation of heat in the lower layer of the materials, resulting in the collapse of the materials and the failure of freeze-drying.

Description

Technical Field

[0001] The present invention relates to the field of freeze-drying of liquid materials, and particularly to a freeze-drying method and device. Background Art

[0002] Freeze-drying refers to the process of freezing a solution-state material below the freezing point, and under vacuum conditions, then through a suitable temperature-raising control program for the frozen material, enabling the water in the material to sublimate and diffuse into the cold trap for refreezing, and finally completely sublimating the water in the frozen material.

[0003] In the existing freeze-drying method, generally only one heat source is provided at the bottom of the material for heating the material from the bottom. When the thickness of the material layer is large, especially for materials with high viscosity, there often occurs a situation where the water in the bottom layer of the material has started to sublimate, but the upper layer of the material has not yet reached the sublimation condition. This will cause water vapor to accumulate in the bottom layer of the material, and further lead to the collapse of the material, resulting in the failure of freeze-drying.

[0004] Therefore, how to avoid the collapse of the material has become an urgent problem to be solved by those skilled in the art. Especially for materials with high viscosity and thick material layers, how to avoid this problem is of great significance for improving production efficiency. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a freeze-drying method and device that can avoid the collapse of the material.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a freeze-drying method for freeze-drying a material placed in a heat-conducting container, including the following steps:

[0008] Supplying heat to the material from the top end of the material;

[0009] When the drying thickness of the material from top to bottom reaches a preset thickness, supplying heat to the material from the bottom end of the material.

[0010] Optionally, the preset thickness is greater than or equal to one-fifth of the total thickness of the material.

[0011] The present invention also provides a freeze-drying device applicable to the above freeze-drying method, including a vacuum chamber, a first heating device and a second heating device. The first heating device and the second heating device are both arranged inside the vacuum chamber, and the first heating device and the second heating device are respectively used to supply heat to the top end and the bottom end of the material.

[0012] Optionally, there is a spacing between the first heating device and the top end of the material, and the first heating device is a radiation heating device.

[0013] Optionally, the top end of the heat-conducting container is open, and there is a gap between the first heating device and the top end of the heat-conducting container.

[0014] Optionally, the first heating device includes a first heat-conducting plate, a first heat exchange channel is arranged in the first heat-conducting plate, a first heat-conducting medium circulates in the first heat exchange channel, and there is a spacing between the first heat-conducting plate and the top end of the material.

[0015] Optionally, the second heating device is in contact with the bottom end of the heat-conducting container, and the second heating device is a conduction heating device.

[0016] Optionally, the second heating device includes a second heat-conducting plate, a second heat exchange channel is arranged in the second heat-conducting plate, a second heat-conducting medium circulates in the second heat exchange channel, and the second heat-conducting plate is in contact with the heat-conducting container.

[0017] Optionally, the heat-conducting container is a transparent heat-conducting container.

[0018] The present invention has achieved the following technical effects compared with the prior art:

[0019] The freeze-drying method provided by the present invention is used for freeze-drying the material placed in the heat-conducting container, and includes the following steps: supplying heat to the material from the top end of the material; when the drying thickness of the material from top to bottom reaches a preset thickness, supplying heat to the material from the bottom end of the material. When the drying thickness of the material from top to bottom reaches the preset thickness, the upper layer of the material, that is, the part of the material that has been dried, will preferentially form a water vapor evacuation path. In this way, when the lower layer of the material, that is, the part of the material that has not been dried, has a temperature rise and water vapor is generated, it can smoothly sublimate and diffuse from the path formed by the upper layer of the material, thereby avoiding the accumulation of heat in the lower layer of the material, resulting in the collapse of the material and the failure of freeze-drying. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of the freeze-drying device provided in the embodiment of the present invention.

[0022] Explanation of the reference numerals: 100, freeze-drying device; 1, vacuum box; 2, first heating device; 3, second heating device; 4, heat-conducting container. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The purpose of the present invention is to provide a freeze-drying method and device capable of avoiding material collapse.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] refer to Figure 1 As shown, the freeze-drying method provided in the embodiment of the present invention is used to freeze-dry the material placed in the heat-conducting container 4, comprising the following steps:

[0027] Supply heat to the material from the top of the material;

[0028] When the drying thickness of the material from top to bottom reaches the preset thickness, heat is supplied to the material from the bottom.

[0029] When the drying thickness of the material from top to bottom reaches the preset thickness, the upper layer of the material, that is, the part of the material that has been dried, will preferentially form a water vapor evacuation path, so that when the temperature of the lower layer of material, that is, the part of the material that has not been dried, rises and water vapor is generated, it can smoothly sublimate and diffuse from the path formed by the upper layer of material, thereby avoiding heat accumulation in the lower layer of material, causing material collapse and freeze-drying failure. In addition, heating the upper layer of the frozen material first will cause the upper layer of material to be dried first. After the upper layer of material is dried, the overall thickness of the material will be reduced, which makes it easier for water vapor to diffuse out. The freeze-drying method provided in the embodiment of the present invention mainly improves the heating method of the heating stage of the traditional freeze-drying method.

[0030] The specific value of the preset thickness depends on the characteristics of the material. During the specific operation, the user can determine the preset thickness through experiments. The preset thickness is, for example, greater than or equal to one fifth of the total thickness of the material.

[0031] In an embodiment of the present invention, a freeze-drying device 100 applicable to the above freeze-drying method is further provided, which includes a vacuum chamber 1, a first heating device 2, and a second heating device 3. The first heating device 2 and the second heating device 3 are both disposed inside the vacuum chamber 1. The first heating device 2 and the second heating device 3 are respectively used to be disposed at the top and bottom of the material to supply heat to the top and bottom of the material respectively. The inside of the vacuum chamber 1 is a vacuum environment, and the vacuum chamber 1 is used to provide a vacuum environment for the freeze-drying of the material. The specific structure of the vacuum chamber 1 belongs to the prior art. For example, it includes a box body and a vacuum pump connected to the inside of the box body. The gas inside the box body is pumped out by the vacuum pump to keep the inside of the box body in a vacuum environment.

[0032] In this embodiment, as Figure 1 shown, there is a spacing between the first heating device 2 and the top of the material. The specific size of the spacing is determined according to actual needs. The first heating device 2 is a radiation heating device, and the radiation heating device realizes heating in a radiation manner.

[0033] Further, the top of the heat-conducting container 4 is open. As Figure 1 shown, there is a gap between the first heating device 2 and the top of the heat-conducting container 4. The purpose of reserving the gap is to diffuse the water vapor in the heat-conducting container 4.

[0034] Further, the first heating device 2 includes a first heat-conducting plate. A first heat exchange channel is provided inside the first heat-conducting plate, and a first heat-conducting medium circulates inside the first heat exchange channel. There is a spacing between the first heat-conducting plate and the top of the material to achieve radiation heating. In the specific use process, the first heat-conducting medium transfers heat to the first heat-conducting plate, and then the first heat-conducting plate heats the material in a radiation manner. The first heating device 2 is not limited to the above form. For example, it can also be a light heating device or a microwave heating device.

[0035] Further, the first heat-conducting medium includes but is not limited to a liquid heat-conducting medium, such as an aqueous solution or heat-conducting oil.

[0036] In this embodiment, as Figure 1 shown, the second heating device 3 is in contact with the bottom end of the heat-conducting container 4. The second heating device 3 is a conduction heating device. The conduction heating device realizes heating in a conduction manner.

[0037] Further, the second heating device 3 includes a second heat-conducting plate. A second heat exchange channel is provided inside the second heat-conducting plate, and a second heat-conducting medium circulates inside the second heat exchange channel. The second heat-conducting plate is in contact with the heat-conducting container 4 to achieve conduction heating. More specifically, the heat-conducting container 4 containing the material is supported on the second heat-conducting plate. In the specific use process, the second heat-conducting medium transfers heat to the second heat-conducting plate, and then the second heat-conducting plate heats the material in a heat conduction manner.

[0038] Further, the second heat-conducting medium includes but is not limited to a liquid heat-conducting medium, such as an aqueous solution or heat-conducting oil.

[0039] In this embodiment, the heat-conducting container 4 is a transparent heat-conducting container, which is convenient for observing the material drying process and can intuitively monitor whether the material is dried to a preset thickness. The heat-conducting container 4 includes but is not limited to a glass container.

[0040] The following will introduce in detail the freeze-drying method and freeze-drying device 100 provided in the embodiments of the present invention in combination with the freeze-drying of ademetionine disulfonate:

[0041] When freeze-drying ademetionine disulfonate, after the material is frozen and the vacuum is pumped, first start the first heating device 2 to supply heat to the material from the top of the material. When the drying thickness of the material from top to bottom reaches the preset thickness, that is, when the sublimation of the water in the upper layer of the material is basically completed, then start the second heating device 3 until the sublimation of all the material moisture is basically ended. After all the moisture in the material is discharged, the material drying is completed. Then, adjust the temperatures of the first heating device 2 and the second heating device 3 to the required discharging temperature to complete the whole process.

[0042] The principles of the freeze-drying method and freeze-drying device 100 provided in the embodiments of the present invention are:

[0043] Let the upper layer of the frozen material sublimate first. After forming a water vapor diffusion path, then let the lower layer of the frozen material sublimate, so as to avoid the water vapor generated by the sublimation of the lower layer of the material being difficult to diffuse smoothly and accumulating in the lower layer of the material, resulting in collapse when drying a thick material.

[0044] In the description of the present invention, it should be noted that some words indicating the orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the orientation in the description of the present invention refers to the orientation when the freeze-drying device 100 provided in the embodiments of the present invention is arranged as Figure 1 shown.

[0045] Specific examples are used in this specification to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be understood as a limitation of the present invention.

Claims

1. A freeze-drying method for freeze-drying a material placed in a heat-conducting container, wherein the heat-conducting container is a transparent heat-conducting container, and is characterized in that, Including the following steps: Heating the material from the top of the material; When the drying thickness of the material from top to bottom reaches a preset thickness, heating the material from the bottom of the material; the preset thickness is greater than or equal to one-fifth of the total thickness of the material.

2. A freeze-drying device applicable to the freeze-drying method described in claim 1, characterized in that, Including a vacuum chamber, a first heating device and a second heating device, the first heating device and the second heating device are both arranged inside the vacuum chamber, and the first heating device and the second heating device are respectively used to heat the top and the bottom of the material.

3. The freeze-drying device according to claim 2, characterized in that, There is a spacing between the first heating device and the top of the material, and the first heating device is a radiation heating device.

4. The freeze-drying device according to claim 3, characterized in that, The top of the heat-conducting container is open, and there is a gap between the first heating device and the top of the heat-conducting container.

5. The freeze-drying device according to claim 3, characterized in that, The first heating device includes a first heat-conducting plate, a first heat exchange channel is arranged inside the first heat-conducting plate, a first heat-conducting medium circulates inside the first heat exchange channel, and there is a spacing between the first heat-conducting plate and the top of the material.

6. The freeze-drying device according to claim 2, characterized in that, The second heating device is in contact with the bottom of the heat-conducting container, and the second heating device is a conduction heating device.

7. The freeze-drying apparatus according to claim 6, characterized in that, The second heating device includes a second heat-conducting plate, a second heat exchange channel is arranged inside the second heat-conducting plate, a second heat-conducting medium circulates inside the second heat exchange channel, and the second heat-conducting plate is in contact with the heat-conducting container.

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