The desktop vacuum freeze dryer has a wide range of application prospects in scientific research, production, and daily life due to its special working principle and many advantages. It is an ideal choice for both preserving precious samples and mass producing high-quality products.

The basic working principle of desktop vacuum freeze dryer:

1. Pre freezing stage: Place the material to be dried in the freeze-drying chamber, and lower the indoor temperature through a refrigeration system to freeze the free water and some bound water in the material. This step ensures that moisture exists in solid form, preparing for subsequent sublimation.

2. Sublimation stage: While maintaining low temperature, start the vacuum pump to extract air from the freeze-drying chamber, creating a low-pressure environment. Due to a significant decrease in pressure, ice directly sublimates from solid to gas (skipping the liquid phase), a process known as "sublimation". At this point, frozen water molecules are converted into water vapor and expelled from the system.

3. Desorption stage: After most of the water has been removed, further increase the temperature to promote the evaporation of the remaining adsorbed water. This step helps to remove residual moisture from the material and ensure the dryness of the product.

4. Collection and Condensation: The water vapor generated throughout the process will be directed to the condenser, where it will re condense into ice or water, thereby preventing it from entering the pump body and causing damage.

Measurement steps for desktop vacuum freeze dryer:

1. Pre freezing stage

-Sample preparation and placement: Place the substance to be dried in a suitable position such as the material tray or basket of the equipment. Generally, it is required that the sample be fully frozen at low temperatures to form a stable solid ice crystal structure. For example, for some biological samples, pharmaceutical preparations, etc., they may need to be pre cooled in a refrigerator before being transferred to a freeze dryer for further freezing.

-Set and maintain freezing temperature: Based on the characteristics and requirements of the sample, set the appropriate freezing temperature through the control system and keep the sample at this temperature for a certain period of time (usually 1-2 hours) to ensure that the sample is frozen solid. If subsequent operations are carried out without solidification, it may cause the sample to rupture and deform under vacuum, and if the liquid substance is present, it may also erupt and cause freeze-drying failure.

2. Sublimation stage

-Turn on the vacuum system: After the sample is frozen, press the buttons such as "vacuum gauge" and "vacuum pump" in sequence (the operation mode may vary slightly for different models of equipment), and start the vacuum pump to start vacuuming. At this point, in a vacuum environment, the moisture in the substance will directly sublime from the ice crystal state to the gaseous state.

-Control sublimation temperature: At the same time, gradually increase the temperature according to the preset program to promote the sublimation of moisture. However, it should be noted that the heating rate should not be too fast to avoid affecting the quality of the sample. During this process, water vapor will be captured by the condenser and condensed into liquid water, which will be collected and discharged from the system.

3. Monitoring and adjustment

-Real time monitoring data: During operation, closely monitor the temperature, vacuum degree, and other data displayed by the control system to ensure that all indicators are within the normal range. Some advanced devices, such as the LGJ-12C model, support remote monitoring (optional), making it easy for operators to remotely operate and troubleshoot.

-Timely end of drying: Determine whether the drying endpoint has been reached based on the actual situation and drying effect of the sample. It can be determined by observing the appearance and weight changes of the sample. After reaching the drying requirements, stop heating and vacuuming operations.

4. Sample retrieval and storage: Carefully retrieve the dried sample and package and store it properly. Be careful to avoid the sample from absorbing moisture or being contaminated again.