CN114184005A - Drying device and method capable of judging primary and secondary drying critical points in freeze-drying process - Google Patents
Drying device and method capable of judging primary and secondary drying critical points in freeze-drying process Download PDFInfo
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- CN114184005A CN114184005A CN202111331012.9A CN202111331012A CN114184005A CN 114184005 A CN114184005 A CN 114184005A CN 202111331012 A CN202111331012 A CN 202111331012A CN 114184005 A CN114184005 A CN 114184005A
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- 238000009777 vacuum freeze-drying Methods 0.000 claims description 12
- 238000002474 experimental method Methods 0.000 claims description 6
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
- F26B5/04—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum
- F26B5/06—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum the process involving freezing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B23/00—Heating arrangements
- F26B23/04—Heating arrangements using electric heating
- F26B23/06—Heating arrangements using electric heating resistance heating
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
- F26B25/22—Controlling the drying process in dependence on liquid content of solid materials or objects
- F26B25/225—Controlling the drying process in dependence on liquid content of solid materials or objects by repeated or continuous weighing of the material or a sample thereof
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- Engineering & Computer Science (AREA)
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- General Engineering & Computer Science (AREA)
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Abstract
The invention relates to a drying device capable of judging primary and secondary drying critical points in a freeze-drying process.A refrigeration system of the drying device comprises a refrigerator, a compressor and a refrigeration coil pipe which are arranged in a case, wherein a refrigeration bin is arranged in the case, and the refrigeration coil pipe is wound at the lower part of the outer wall of the refrigeration bin; the vacuum system comprises a vacuum pump, a vacuum regulating valve and a vacuum gauge, the vacuum pump is connected to the freeze-drying bin through a vacuum pipeline, and the vacuum regulating valve and the vacuum gauge are arranged on the vacuum pipeline; the heating system is positioned in the freeze-drying bin and comprises an electric heating plate and a defrosting electric heating plate; the measuring system comprises a support, a partition plate, an S-shaped tension and compression sensor, a first temperature sensor, a second temperature sensor, a wireless transmission antenna and a control unit, wherein the support, the partition plate, the S-shaped tension and compression sensor, the first temperature sensor, the second temperature sensor, the wireless transmission antenna and the control unit are arranged in the freeze-drying bin. The drying device and the drying method can detect the drying state of the material in real time, accurately judge the boundary point and the end point of the primary drying stage and the secondary drying stage, effectively improve the drying efficiency and improve the product quality.
Description
Technical Field
The invention belongs to the technical field of vacuum freeze drying, and particularly relates to a device and a method capable of judging primary and secondary drying critical points in a freeze drying process, which are particularly suitable for related experiments of freeze drying of heat-sensitive materials such as medicines, foods and the like in scientific research.
Background
As is well known, lyophilization is divided into three stages as shown in FIG. 2. A prefreezing stage, a primary drying stage (sublimation drying stage), and a secondary drying stage (desorption drying stage), wherein in the prefreezing stage: freezing the water-containing material below freezing point to convert the water in the material into ice. The free water of the material is removed in the primary drying process, and the residual bound water is removed in the secondary drying process. The drying method is characterized in that ice is converted into water vapor under the high vacuum environment during the whole drying process, so that the ice is removed. However, the two stages of primary drying and secondary drying in the vacuum freeze-drying process are the main stages of energy consumption, and account for about 87% of the whole process. Excessive drying in the drying process can lead to unnecessary energy waste, and the quality of the product can be reduced after the drying is finished in advance, so that the product requirement cannot be met. Therefore, the method is important for judging the primary drying end point and the secondary drying end point of the freeze drying process, and not only can the ineffective drying be reduced, but also the drying rate can be improved, and the energy waste can be reduced. At present, the types of freeze dryers on the market are different from each other, and a series of problems that the drying state of a material cannot be accurately judged, whether the drying is finished or not depends on experience and the like exist.
For two decades, many researchers at home and abroad have focused on developing new demarcation point methods for detecting the freeze-drying stage, however the extreme conditions involved in the freeze-drying process (low temperature, high vacuum, sterility) make this task very challenging. Nevertheless, many references to related methods and apparatus are available for review and purchase. However, they cannot automatically detect when the water in the material is completely sublimated, which is the core purpose and technology of this patent.
Patent CN 213335194U has proposed a freeze dryer that medicine processing used, and the device includes freeze dryer body, heat dissipation grid, display screen, control button, axis of rotation, side maintenance window, circular recess, freeze-drying storehouse, its characterized in that: simple structure, reasonable design, convenient use and good heat dissipation effect. However, the patent fails to monitor the material condition.
Patent CN 207764670U has proposed a freeze dryer temperature-detecting device and has contained temperature-detecting device's temperature control system, has installed temperature-detecting device including setting up the infrared radiation thermometer in the freeze dryer box outside and setting up the infrared ray glass that passes through on the freeze dryer box. The temperature control system can transmit real-time data with a PLC controller, and realizes automatic control of the temperature of the freeze dryer. However, the method for measuring materials in the patent is not contact measurement, and the temperature difference is large by an infrared measurement method.
Patent CN 210486286U has provided a novel freeze dryer, has solved the inconvenient problem of using of general freeze dryer, can be fast and effectual putting the medicine bottle, has avoided the medicine bottle to appear damaged phenomenon putting the in-process. Although the work efficiency of people has also been improved when improving medicine bottle and putting efficiency, but this patent can not shorten freeze-drying time, also can not judge the demarcation point of primary drying and secondary drying.
Patent CN 203336903U has proposed an experiment type freeze dryer integration equipment, conveniently realizes related instruments centralized management such as freeze dryer, improves laboratory freeze dryer's availability factor, reduces the energy consumption when moving, reduces the pollution of freeze dryer operation to the laboratory. But the device cannot judge the material drying state.
Therefore, how to judge the drying degree of the material in the freeze-drying process, define the boundary point between primary drying and secondary drying, shorten the drying time and reduce the energy consumption is a problem to be solved urgently by the technical personnel in the field.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a drying device capable of judging the primary and secondary drying critical points in the freeze-drying process.
The invention also provides a drying method based on the drying device capable of judging the primary and secondary drying critical points in the freeze-drying process, the method not only can detect the drying state of the material in real time, but also can accurately judge the drying end point of the material, and can also measure the temperature of the material and the partition plate in real time, further judge and verify the accuracy of the primary drying and secondary drying boundary point of the material according to the temperature change, and control the temperature of the product, thereby improving the product quality.
The invention aims to be realized by the following technical scheme:
a drying device capable of judging primary and secondary drying critical points in a freeze-drying process comprises a freezing system, a vacuum system, a heating system, a measuring system and a control system;
the refrigerating system comprises a refrigerator, a compressor and a refrigerating coil which are arranged in a case, a refrigerating bin is arranged in the case, and the refrigerating coil is wound on the lower part of the outer wall of the refrigerating bin;
the vacuum system comprises a vacuum pump, a vacuum regulating valve and a vacuum gauge, the vacuum pump is connected to the freeze-drying bin through a vacuum pipeline, and the vacuum regulating valve and the vacuum gauge are arranged on the vacuum pipeline;
the heating system is positioned in the freeze-drying bin and comprises an electric heating plate and a defrosting electric heating plate;
the measuring system comprises a support, a partition plate, an S-shaped tension and compression sensor, a first temperature sensor, a second temperature sensor, a wireless transmission antenna and a control unit, wherein the support, the partition plate, the S-shaped tension and compression sensor, the first temperature sensor and the second temperature sensor are arranged in a freeze-drying bin;
the control system comprises a controller, a frequency converter, a power supply and a control panel, wherein the S-shaped pull-press sensor, the first temperature sensor, the second temperature sensor and the third temperature sensor are connected to a wireless transmission antenna through data lines, and the wireless transmission antenna is in remote communication connection with the controller.
And the outside of the case and the outside of the refrigeration coil are wrapped by heat-insulating materials, so that the load of the refrigerator is reduced.
And a vacuum gauge arranged on the vacuum pipeline collects pressure signals and transmits the pressure signals to the controller, and the pressure is adjusted through the vacuum adjusting valve.
Moreover, the S-shaped tension and compression sensor is wrapped by a heat insulation material, so that the influence of temperature change on the accuracy of the sensor is avoided.
Moreover, freeze-drying storehouse upper portion sets up ya keli dustcoat, adopts vacuum silicone grease to carry out sealing connection top cap at ya keli dustcoat top, guarantees the vacuum.
And the bottom of the freeze-drying bin is provided with a drain pipe, so that water condensed around the refrigeration coil pipe can be drained after drying is finished.
Moreover, the control panel adopts a capacitive touch screen, and a usb and a data transmission port are arranged on the side face, so that data processing and operation are convenient during experiments.
A drying method based on a drying device capable of judging primary and secondary drying critical points in a freeze-drying process is characterized in that: the method comprises the following steps:
1) and (3) a freezing stage: turning on a power switch, turning on a refrigerator on a control panel, starting the refrigeration by a refrigeration system, rapidly reducing the temperature, and when the refrigeration temperature is reduced to minus 40-60 ℃, putting the material on a partition plate for freezing;
2) vacuum freeze drying stage: after the materials are completely frozen, closing the drainage valve, sealing a top cover on the acrylic outer cover to ensure the vacuum degree, opening a vacuum pump, setting a vacuum value, starting to vacuumize the freeze-drying bin, and performing vacuum freeze-drying operation;
3) judging primary and secondary drying critical points: along with vacuum freeze drying constantly goes on, but S type draws the mass change that presses the sensor real-time assay material, judges the dry state of material according to the mass change, and the judgement process is:
the S-type tension-compression sensor measures the total mass G of the material, and when the total mass G of the material is GFixing device+(GFixing deviceX 10%) G, wherein GFixing deviceThe absolute dry quality of the material can be judged, the secondary drying is started after the primary drying is finished, and the temperature of the material approaches to the temperature of the partition board after the primary drying is finished;
after the primary drying stage is finished, raising the temperature of the heating plate to 30-45 ℃, and finishing the secondary drying stage to continue drying;
4) and (4) finishing drying: stopping drying, closing the vacuum pump, making the freeze-drying storehouse resume normal pressure, closing the refrigerator afterwards, closing the electric plate, opening the outlet, when freeze-drying storehouse pressure becomes the ordinary pressure, take off ya keli dustcoat and top cap, take out the material, the drying is finished.
The invention has the advantages and beneficial effects that:
1. the drying device capable of judging the primary drying critical point and the secondary drying critical point in the freeze-drying process can directly freeze materials in the freeze-drying bin and prepare dried products through the vacuum freeze-drying process, the whole process is finished in the same equipment, the frozen materials do not need to be transferred, and the equipment integration degree is high.
2. According to the drying device capable of judging the critical point of primary drying and secondary drying in the freeze-drying process, the first temperature sensor is in direct contact with the material in the primary drying stage and the secondary drying stage, and compared with the drying device capable of measuring temperature more accurately by infrared, the drying device is convenient for the electric heating plate to control the temperature of the material, and can produce products with higher quality.
3. According to the drying device capable of judging the primary drying critical point and the secondary drying critical point in the freeze-drying process, the first temperature sensor and the second temperature sensor are made of the ultra-fine K-type thermocouples, the diameters of the thermocouples are about 0.1mm, the temperature of the material can be measured while the quality change of the material is not influenced, and the influence of the weight of the temperature sensors on the actual weight of the product is avoided. The data accuracy is improved.
4. According to the drying device capable of judging the primary and secondary drying critical points in the freeze-drying process, the S-shaped tension-compression sensor is arranged in the freeze-drying bin, the quality of the material is detected through the S-shaped tension-compression sensor, the heating temperature of the material is adjusted through the control panel, the drying temperature is controlled within a reasonable range according to the actually measured material temperature, the drying time can be greatly shortened, the drying efficiency is improved, and the drying device is very suitable for thermosensitive materials such as medicines, foods and the like.
5. According to the drying device capable of judging the primary and secondary drying critical points in the freeze-drying process, the S-shaped tension-compression sensor is a core component for judging the quality change of materials, and the heat insulation protective layer is arranged around the tension-compression sensor, so that the influence of temperature change on the precision of the tension-compression sensor is prevented.
6. The drying device capable of judging the primary and secondary drying critical points in the freeze-drying process can accurately judge the boundary point of the primary drying stage and the secondary drying stage according to the mass change and the temperature change of materials in the vacuum freeze-drying process, can realize real-time automatic monitoring of the weight of the materials during sublimation in the drying process, can operate in the low-temperature, high-vacuum and sterile environment of equipment, can shorten the drying time and improve the product quality, provides theoretical guidance and technical support for the mass production of freeze-drying, and solves a great problem of freeze-drying.
7. The drying device capable of judging the primary drying critical point and the secondary drying critical point in the freeze-drying process can set different vacuum degrees by adjusting the vacuum valve, and sets corresponding vacuum values according to the requirements of different products on the vacuum degrees, thereby realizing variable control and facilitating scientific research.
8. The drying device capable of judging the primary drying critical point and the secondary drying critical point in the freeze-drying process introduces the technology of Internet of things, and the top end of the freeze dryer is provided with the antenna for remote data transmission and remote acquisition of experimental data, so that the processing is convenient and the time is saved.
9. According to the drying device capable of judging the primary drying critical point and the secondary drying critical point in the freeze-drying process, the refrigeration coil and the pipeline are wrapped by the heat insulation material, so that the temperature in the circulating pipeline can be maintained in a low-temperature state, the temperature in the freeze-drying bin is ensured to be constant, and the materials are ensured not to melt in the freeze-drying process. Further ensuring the product quality.
10. According to the drying device capable of judging the primary drying critical point and the secondary drying critical point in the freeze-drying process, after freeze-drying is finished, water vapor condensed near the cold trap can be quickly melted into water through the defrosting function and then is discharged through the drain pipe, so that equipment is cleaned more conveniently and quickly.
11. The drying device capable of judging the primary drying critical point and the secondary drying critical point in the freeze-drying process only needs to put materials into the cabinet in the whole drying process, so that the interference of human factors is reduced, and the data accuracy of equipment is improved.
12. The drying device capable of judging the primary and secondary drying critical points in the freeze-drying process has the characteristics of simple structure, convenience in operation and high integration degree, can help scientific researchers to better research the mechanism of the freeze-drying process, and aims to provide technical support for the process optimization of freeze-dried products.
13. The drying device and the drying method can judge the critical point of primary drying and secondary drying in the freeze-drying process, can detect the drying state of the material in real time, accurately judge the residual moisture content in the product, accurately judge the boundary point and the end point of the primary drying stage and the secondary drying stage, can effectively improve the drying efficiency and the product quality, and have important significance for the production of high value-added food, medicines and biological products.
Drawings
FIG. 1 is a schematic diagram of the structure of an experimental freeze dryer of the present invention;
FIG. 2 is a schematic diagram of a freeze-drying process;
FIG. 3 is a graph showing the variation of mass of a material using the drying apparatus of the present invention;
FIG. 4 is a graph showing the temperature change of the material and the partition using the drying apparatus of the present invention.
Drawings
The refrigerator comprises a top cover 1, a acrylic outer cover 2, a tension and compression sensor 3-S type, a support 4, a data line 5, a partition plate 6, a first temperature sensor 7, a second temperature sensor 8, an electric heating plate 9, a defrosting electric heating plate 10, a refrigerating coil 11, a compressor 12, a drain pipe 13, a valve 14, a wireless transmission antenna 15, a cabinet 16, a control panel 17, a refrigerator 18, a vacuum regulating valve 19, a vacuum pump 20, a vacuum gauge 21, a third temperature sensor 22 and a cold trap 23.
Detailed Description
The present invention is further illustrated by the following specific examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.
A drying device capable of judging primary and secondary drying critical points in a freeze-drying process comprises a freezing system, a vacuum system, a heating system, a measuring system and a control system.
The refrigeration system comprises a refrigerator 18, a compressor 12 and a refrigeration coil 11 which are arranged in the case, the refrigerator, the compressor and the refrigeration coil are circularly communicated, the refrigeration coil is arranged at the periphery of the bottom of a freeze-drying bin in the case to refrigerate the freeze-drying bin, and a cold trap 22 is formed at the lower part of the freeze-drying bin;
the vacuum system comprises a vacuum pump 20, a vacuum regulating valve 19 and a vacuum gauge 21, the vacuum pump is connected to the freeze-drying bin in the case through a vacuum pipeline, the vacuum pipeline is provided with the vacuum regulating valve and the vacuum gauge, and the vacuum system provides negative pressure for the freeze-drying bin.
The heating system is positioned inside the freeze-drying bin and comprises an electric heating plate 9 and a defrosting electric heating plate 10, the electric heating plate is positioned on the lower portion of a partition plate in the freeze-drying bin, and the defrosting electric heating plate is positioned on the inner wall of the lower portion of the freeze-drying bin.
The measuring system comprises a support 4, a partition plate 6, an S-shaped tension and compression sensor 3, a first temperature sensor 7, a second temperature sensor 8, a wireless transmission antenna 15 and a control unit, wherein the partition plate is hoisted at the lower part of the support through the S-shaped tension and compression sensor, the support is fixedly installed with the freeze-drying bin, the electric heating plate is arranged at the bottom of the partition plate, the S-shaped tension and compression sensor measures the quality of the partition plate, the electric heating plate and materials on the electric heating plate in real time, and the partition plate and the electric heating plate are fixed in quality and are connected with the S-shaped tension and compression sensor 3, so before drying, the data of the S-shaped tension and compression sensor 3 needs to be zeroed through a control panel 17, and the S-shaped tension and compression sensor 3 only measures the quality of the materials and a tray. Secondly, the quality of the tray for containing the materials is determined, and the data displayed in real time by the S-shaped tension and compression sensor 3 is corrected through the control panel 17, namely, the quality of the tray is reduced, so that the sensor only measures and displays the real-time change of the quality of the materials. The first temperature sensor measures the temperature of the material, the second temperature sensor measures the temperature of the partition, and the third temperature sensor 22 measures the temperature in the refrigeration coil. Freeze-drying storehouse upper portion sets up ya keli dustcoat 2, adopts vacuum silicone grease to carry out sealing connection top cap 1 at ya keli dustcoat top, guarantees the vacuum. The bottom of the freeze-drying bin is provided with a drain pipe 13, a drain valve 14 is arranged on the drain pipe, and water condensed in the freeze-drying bin at the position of the refrigeration coil pipe can be drained after drying is finished.
The control system comprises a controller, a frequency converter, a power supply and a control panel 17, wherein the S-shaped pull-press sensor, the first temperature sensor, the second temperature sensor and the third temperature sensor are connected to a wireless transmission antenna through a data line 5, and the wireless transmission antenna is in remote communication connection with the controller.
The outside of the case 16 and the outside of the refrigeration coil are wrapped by heat insulation materials, so that the load of the refrigerator is reduced. The S-shaped tension-compression sensor is wrapped by a heat insulation material, so that the influence of temperature change on the accuracy of the sensor is avoided. A vacuum gauge 21 arranged on the vacuum pipeline collects pressure signals and transmits the pressure signals to the controller, and the pressure is adjusted through a vacuum adjusting valve.
The control panel adopts a capacitive touch screen, and a usb and a data transmission port are arranged on the side face, so that data processing and operation are convenient during experiments.
A drying method of a drying device capable of judging primary and secondary drying critical points in a freeze-drying process comprises the following steps:
1) and (3) a freezing stage: closing the valve 14, opening a power switch, opening a refrigerator on the control panel, starting the compressor after the refrigerator runs for 2min, starting the refrigeration of the refrigeration system, rapidly reducing the temperature, starting the temperature reduction in the cold trap, freezing the material when the temperature displayed on the control panel by the third temperature sensor reaches about minus 50 ℃, removing the top cover of the freeze-drying bin from the acrylic outer cover, placing the tray containing the material on the partition plate, inserting the first temperature sensor into the material, measuring the change temperature of the material in real time, and ending the refrigeration stage after the material is completely frozen.
2) And (3) a freeze drying stage: seal top cap on the ya keli dustcoat, scribble freeze-drying storehouse top cap and ya keli dustcoat with vacuum silicone grease at both junctions, guarantee its gas tightness with this, open the vacuum pump, set up the vacuum value, begin to the vacuum pumping of freeze-drying storehouse, carry out freeze-drying operation, observe the change condition of vacuum value in real time through the vacuometer, when pressure reaches 10Pa and keeps unchangeable, it is good to explain the gas tightness, adjust vacuum control valve 19 according to the experiment demand again, make it reach required vacuum value, so far, the freeze-drying stage begins, the vapor that rises in the freeze-drying process material and overflows is collected by the cold-trap 23 inner wall in freeze-drying storehouse after condensing.
3) Judging primary and secondary drying critical points: along with freeze-drying constantly goes on, but S type draws the mass change that presses the sensor real-time assay material, just can judge the dry state of material according to the mass change, and the judgement process is:
the S-type tension-compression sensor measures the total mass G of the material, and when the total mass G of the material is GFixing device+(GFixing deviceX 10%) G, wherein GFixing deviceThe quality of the oven-dry material can be judged, the secondary drying is started after the primary drying is finished, and the temperature of the material approaches to the temperature of the partition plate after the primary drying is finished.
In practical operation, it is first necessary to ensure that the mass of the material put in each batch is the same, and the absolute dry mass G of the material needs to be measured before dryingFixing deviceAnd the moisture removal condition is monitored in real time by a value displayed by a weight sensor in the freeze drying process, and the material quality is reduced rapidly in the primary drying stage as shown in fig. 3, which indicates that the moisture sublimation speed is rapid. The weight at this time is the absolute dry mass GFixing device。
As can be seen from fig. 4, the material temperature and the separator temperature gradually approach the same value at a certain time point in the later stage of freeze-drying, and the time point when the two temperatures are the same value coincides with the time point of the boundary point between the primary drying stage and the secondary drying stage determined by the weight. In actual operation, the accuracy of the boundary point can be further verified and judged according to the temperature of the material and the temperature of the partition plate, namely when the temperature of the material is the same as that of the partition plate, the end of the primary drying stage can be judged.
Freeze drying is divided into two stages in drying stage, primary drying stage and secondary drying stage, and removing in sublimation stageFree water in the material is removed in the secondary drying stage, and the bound water attached to the pore structure of the material is removed, so that the water content of the material is usually less than 10% of the solid, namely when the total mass of the material reaches solid GFixing device+(GFixing deviceX 10%) of (wherein GFixing deviceThe absolute dry mass of the material), the end of primary drying and the beginning of secondary drying can be judged. Therefore, the dividing point can be judged by the real-time change value of the weight of the material by utilizing the material change principle in the freeze drying process, and the device and the method are based on the principle.
As shown in fig. 2, it can be seen from the graph that when the material is in the primary drying stage, the material quality decreases faster, and after the primary drying is finished, the material quality is maintained in a more constant state. In the analysis stage, the material quality reduction speed is very slow, and the residual water in the material is the bound water in the stage, and the bound water is adsorbed on the inner wall of the pore structure of the material and polar groups through weak molecular forces such as hydrogen bonds and the like. To remove this water, intermolecular forces need to be overcome, i.e., more energy is required. The temperature of the partition board can be raised through the heating plate 9, so that the residual moisture in the material is volatilized. At the time of the sublimation stage, the temperature of the material and the partition plate 6 can be measured by the device, and the temperature curve data graph 3 shows that the temperature of the material is approximately the same as that of the partition plate 6 in 600min, at the moment, free water in the material is sublimated, only a small part of bound water is inside the material, so that the temperature change is not obvious, and the definition of a primary drying and secondary drying boundary point through the mass change of the material is further verified to be accurate.
After the primary drying stage is finished, raising the temperature of the heating plate to 30-45 ℃ to finish the secondary drying stage; the method specifically comprises the following steps: the first temperature sensor is used for measuring the real-time temperature in the material, and the second temperature sensor is used for measuring the temperature of the partition plate; the value of the S-shaped tension and compression sensor connected with the control panel 17 is gradually reduced along with the volatilization of the moisture in the material; when the primary drying is finished, the temperature of the heating plate 9 can be raised to 40 ℃ until the drying is finished, because the bound water attached to the inner part of the material can be removed by higher heat. Throughout the drying period, the control panel records data per second and transmits in real time via the antenna.
4) And (4) finishing drying: stopping drying, closing the vacuum pump, making the freeze-drying storehouse resume normal pressure, closing the refrigerator afterwards, closing the electric plate, opening the outlet, when freeze-drying storehouse pressure becomes the ordinary pressure, take off ya keli dustcoat and top cap, take out the material, the drying is finished. The defrosting electric heating plate 10 is opened, and the condensate water valve 14 is opened.
This device accomplishes whole material in freeze-drying storehouse and freezes, vacuum freeze-drying process, and freezing process need not use cryogenic liquids, avoids cryogenic liquids and material contact, freezes the material and need not to shift directly dry in freeze-drying storehouse, avoids the contaminated risk of material completely. The system is closed, so that the sterility of the freeze drying process is further improved, the environment is not polluted, and the production energy consumption and the processing cost are reduced. The drying process is carried out in a high vacuum environment, the heating temperature is controllable, and the method is also suitable for freeze drying of other heat-sensitive materials.
The above method is a detailed explanation of the determination method and principle of the primary drying and secondary drying stages. In our actual operation, can heat the material in primary drying stage and secondary drying stage, guarantee in primary drying stage that heating temperature can not exceed the eutectic point temperature of material, if the heat that the hot plate provided is greater than the required heat of material moisture sublimation, then can lead to the inside temperature of material to rise, when the eutectic point temperature that exceeds the material, then can produce the interior tissue collapse, influence the appearance quality of material, so when setting up the hot plate temperature, can carry out different settlement according to the physical characteristics of different materials. In the secondary drying stage, the residual water in the material is the bound water which is adsorbed on the inner wall of the pore structure of the material and the polar groups through weak molecular force such as hydrogen bonds. To remove this water, it is necessary to overcome the intermolecular forces, i.e., to require more heat.
After the demarcation point is determined by the method, the temperature of the heating plate can be increased after the primary drying stage is finished, and the temperature is generally set to be 30-45 ℃. The purpose of heating at this stage is to shorten the drying time of the secondary drying stage, thereby improving the overall drying efficiency, saving energy and reducing energy consumption. The purpose of accurately judging the primary drying and secondary drying boundary point is to accurately increase the heat of the material in accurate time, shorten the drying time and further improve the product quality.
This device accomplishes whole material in freeze-drying storehouse and freezes, vacuum freeze-drying process, and freezing process need not use cryogenic liquids, avoids cryogenic liquids and material contact, freezes the material and need not to shift directly dry in freeze-drying storehouse, avoids the contaminated risk of material completely. The system is closed, so that the sterility of the freeze drying process is further improved, the environment is not polluted, and the production energy consumption and the processing cost are reduced. The drying process is carried out in a high vacuum environment, the heating temperature is controllable, and the method is also suitable for freeze drying of other heat-sensitive materials.
Although the embodiments of the present invention and the accompanying drawings have been disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, alterations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and thus the scope of the invention is not limited to the embodiments and drawings disclosed.
Claims (8)
1. A drying device capable of judging primary and secondary drying critical points in a freeze-drying process comprises a freezing system, a vacuum system, a heating system, a measuring system and a control system;
the refrigerating system comprises a refrigerator, a compressor and a refrigerating coil which are arranged in a case, a refrigerating bin is arranged in the case, and the refrigerating coil is wound on the lower part of the outer wall of the refrigerating bin;
the vacuum system comprises a vacuum pump, a vacuum regulating valve and a vacuum gauge, the vacuum pump is connected to the freeze-drying bin through a vacuum pipeline, and the vacuum regulating valve and the vacuum gauge are arranged on the vacuum pipeline;
the heating system is positioned in the freeze-drying bin and comprises an electric heating plate and a defrosting electric heating plate;
the measuring system comprises a support, a partition plate, an S-shaped tension and compression sensor, a first temperature sensor, a second temperature sensor, a wireless transmission antenna and a control unit, wherein the support, the partition plate, the S-shaped tension and compression sensor, the first temperature sensor and the second temperature sensor are arranged in a freeze-drying bin;
the control system comprises a controller, a frequency converter, a power supply and a control panel, wherein the S-shaped pull-press sensor, the first temperature sensor, the second temperature sensor and the third temperature sensor are connected to a wireless transmission antenna through data lines, and the wireless transmission antenna is in remote communication connection with the controller.
2. The drying device of claim 1, wherein the drying device is capable of determining the critical point of the primary drying and the secondary drying of the lyophilization process, and comprises: the outside of the case and the outside of the refrigeration coil are wrapped by heat insulation materials, so that the load of the refrigerator is reduced.
3. The drying device of claim 1, wherein the drying device is capable of determining the critical point of the primary drying and the secondary drying of the lyophilization process, and comprises: and a vacuum gauge arranged on the vacuum pipeline collects pressure signals and transmits the pressure signals to the controller, and the pressure is adjusted through the vacuum adjusting valve.
4. The drying device of claim 1, wherein the drying device is capable of determining the critical point of the primary drying and the secondary drying of the lyophilization process, and comprises: the S-shaped tension-compression sensor is wrapped by a heat insulation material, so that the influence of temperature change on the accuracy of the sensor is avoided.
5. The drying device of claim 1, wherein the drying device is capable of determining the critical point of the primary drying and the secondary drying of the lyophilization process, and comprises: freeze-drying storehouse upper portion sets up ya keli dustcoat, adopts vacuum silicone grease to carry out sealing connection top cap at ya keli dustcoat top, guarantees the vacuum.
6. The drying device of claim 1, wherein the drying device is capable of determining the critical point of the primary drying and the secondary drying of the lyophilization process, and comprises: the bottom of the freeze-drying bin is provided with a drain pipe, and water condensed around the refrigeration coil pipe can be drained after drying is finished.
7. The drying device of claim 1, wherein the drying device is capable of determining the critical point of the primary drying and the secondary drying of the lyophilization process, and comprises: the control panel adopts the capacitive touch screen, and is provided with a usb and a data transmission port on the side, so that data and operation are conveniently processed during an experiment.
8. A drying method based on the drying device of any one of claims 1 to 7, which can determine the critical point of primary and secondary drying in the freeze-drying process, characterized in that: the method comprises the following steps:
1) and (3) a freezing stage: turning on a power switch, turning on a refrigerator on a control panel, starting the refrigeration by a refrigeration system, rapidly reducing the temperature, and freezing the material on a partition plate when the refrigeration temperature is reduced to minus 40-60 ℃;
2) vacuum freeze drying stage: after the materials are completely frozen, closing the drainage valve, sealing a top cover on the acrylic outer cover to ensure the vacuum degree, opening a vacuum pump, setting a vacuum value, starting to vacuumize the freeze-drying bin, and performing vacuum freeze-drying operation;
3) judging primary and secondary drying critical points: along with vacuum freeze drying constantly goes on, but S type draws the mass change that presses the sensor real-time assay material, judges the dry state of material according to the mass change, and the judgement process is:
the S-type tension-compression sensor measures the total mass G of the material, and when the total mass G of the material is GFixing device+(GFixing deviceX 10%) G, wherein GFixing deviceThe absolute dry quality of the material can be judged, the secondary drying is started after the primary drying is finished, and the temperature of the material approaches to the temperature of the partition board after the primary drying is finished;
after the primary drying stage is finished, raising the temperature of the heating plate to 30-45 ℃, and finishing the secondary drying stage to continue drying;
4) and (4) finishing drying: stopping drying, closing the vacuum pump, making the freeze-drying storehouse resume normal pressure, closing the refrigerator afterwards, closing the electric plate, opening the outlet, when freeze-drying storehouse pressure becomes the ordinary pressure, take off ya keli dustcoat and top cap, take out the material, the drying is finished.
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| CN101419015A (en) * | 2008-09-02 | 2009-04-29 | 上海理工大学 | Method for judging once lyophilization drying end point and secondary drying end point |
| US20210239396A1 (en) * | 2020-02-04 | 2021-08-05 | Regeneron Pharmaceuticals, Inc. | Target residual moisture content for lyophilized drug product |
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Application publication date: 20220315 Assignee: Ningbo Sanchuan Equipment Manufacturing Co.,Ltd. Assignor: TIANJIN University OF SCIENCE AND TECHNOLOGY Contract record no.: X2024980009885 Denomination of invention: Drying device and method for determining the critical points of primary and secondary drying in the freeze-drying process Granted publication date: 20230505 License type: Common License Record date: 20240717 |
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