The ordinary upper and lower compartment silicone oil freeze dryer (Lyophilizer) is a commonly used equipment in freeze-drying technology. It uses low temperature and vacuum to sublime and remove moisture from materials, retaining their structure and activity. It is widely used in industries such as pharmaceuticals, biology, and food. The freeze-drying process involves several main steps, and the following is a detailed explanation of the freeze-drying process application of this equipment:
1. Freezing stage (cooling stage)
Temperature setting: During the freezing stage of the freeze dryer, the material is cooled to a low temperature state, usually between -40 ° C and -80 ° C. The temperature of the sample is reduced to the required low temperature through the silicone oil circulation heating or cooling system of the upper compartment cooling system.
Moisture freezing: The moisture in the material will quickly freeze and form ice crystals at this stage. The formation of ice crystals during the freeze-drying process has a significant impact on the structure and quality of the material. The size, distribution, and morphology of ice crystals directly affect the quality of the final freeze-dried product.
2. Primary drying stage (sublimation stage)
Vacuum conditions: After freezing, the material enters vacuum conditions, usually controlled at a pressure below 1 Pa. In this vacuum environment, ice crystals are transformed into water vapor through sublimation, directly changing from solid to gas, avoiding the formation of liquid state.
Temperature control: Temperature control during the primary drying stage is very important, generally controlled between -20 ° C and -50 ° C. Excessive temperature can cause ice crystals to melt, while insufficient temperature may result in slow sublimation rate, affecting the drying effect.
The function of silicone oil: Silicone oil provides heat to the upper chamber through heating and conduction, ensuring the appropriate sublimation temperature of the material. The silicone oil circulation system in the upper and lower compartments helps maintain constant temperature conditions and avoid the effects of temperature fluctuations.
3. Secondary drying stage (adsorption stage)
Moisture removal: After primary drying, although most of the moisture has been removed by sublimation, there will still be a small amount of residual moisture. The goal of the secondary drying stage is to remove these remaining moisture, usually achieved through slow heating and maintaining low vacuum.
Temperature rise: The temperature during the secondary drying stage is usually set at 20 ° C to 40 ° C to help the moisture continue to evaporate. The main purpose of this stage is to reduce the moisture content in the material to achieve the final drying standard.
Adsorption of moisture: By reducing the vacuum degree and heating appropriately, residual moisture will continue to be removed. The heat provided by the silicone oil system is particularly important at this stage to ensure uniform drying of the material.
4. End of freeze-drying and product output
Product release: Once secondary drying is completed, the moisture content in the sample has decreased to the target range, typically around 2% -5%. At this point, the material has been freeze-dried and has very low moisture activity, making it easy to store and not prone to spoilage.
Vacuum release: In order to prevent the material from absorbing moisture due to air entering, the freeze-drying machine will first release the vacuum and gradually restore it to normal pressure.
Application of freeze-drying process:
The freeze-drying process of ordinary upper and lower compartment silicone oil freeze dryers has been widely used in multiple fields, mainly including the following aspects:
1. Pharmaceutical industry
Vaccines and biologics: Freeze drying is used to prepare vaccines, antibodies, and other biologics, which can effectively retain their active ingredients and prevent inactivation caused by high temperature or moisture.
Oral solid dosage form: Some drugs, such as antibiotics, hormones, etc., are converted into dry powders using freeze-drying technology for easy storage and transportation.
2. Food industry
Instant food: such as coffee, soup, fruits, etc. Freeze drying can preserve the original taste and nutritional components of the food, making it easy to store for a long time.
Food: For example, freeze-drying preparation of high-end food can improve the quality of food, preserve its original flavor, and extend its shelf life.
3. Biotechnology industry
Freeze drying of cells and microorganisms: Biological samples, such as cells, enzymes, microorganisms, etc., are often preserved for their activity through freeze-drying. This process enables biological samples to rehydrate and restore their biological activity when needed.
4. Chemicals and Fine Chemicals
Some chemical reagents or fine chemicals require freeze-drying to remove moisture in order to maintain their purity and stability.
Summary:
The freeze-drying process of a regular upper and lower compartment silicone oil freeze dryer can effectively remove moisture from materials while retaining their structure, activity, and nutritional components. Its application not only plays an important role in the fields of pharmaceuticals, food, and biotechnology, but is also widely used in the fields of chemicals and scientific research. By precisely controlling temperature, pressure, and time, we ensure that the material achieves the desired freeze-drying effect.