Low temperature freeze dryer (also known as freeze dryer, freeze vacuum dryer) is a device used to convert liquid samples into solids, widely used in pharmaceutical, food, chemical and other fields. The basic principle is to freeze the sample and remove moisture under vacuum conditions. The following are the operating procedures for a low-temperature freeze dryer:
1. Preparation before operation
Equipment inspection:
Check if all components of the freeze dryer are functioning properly, including the cooling system, vacuum system, and heating system.
Ensure that all connections are good and there are no air leaks.
Sample preparation:
Select appropriate sample containers (such as trays, bottles, etc.) as needed to ensure that the containers can withstand low temperatures and vacuum environments.
Adjust the concentration and volume of the sample to achieve the desired drying effect.
Freezing setting:
To determine the freezing temperature and time, it is usually necessary to freeze the sample to -40 ° C or lower, depending on the nature of the sample.
2. Operation steps
Frozen samples:
Place the prepared samples on the sample rack or tray, ensuring there is enough space between the samples for freezing and drying.
Start the freezing system and wait for the sample to freeze to the set temperature.
Vacuum pumping:
After the sample is frozen, start the vacuum pump to extract the air from the chamber.
Monitor the vacuum level to ensure that the required vacuum level is achieved (usually between 0.1-0.3 mbar).
Sublimation process:
Set the temperature of the heating plate, usually between 0 ° C and 40 ° C, to promote moisture sublimation in the sample.
Monitor the sublimation process, observe changes in the state of the sample, and adjust the temperature and vacuum degree if necessary.
3. Monitoring and recording
Temperature and pressure monitoring:
Real time monitoring of sample temperature and vacuum level to ensure safe operation.
Use the control system to record key data for subsequent analysis and reference.
Observe sample changes:
Regularly inspect the appearance of the samples to ensure a smooth drying process.
4. Operation completed
Restore normal pressure:
After drying is completed, slowly increase the pressure inside the chamber to avoid rapid recovery and damage to the sample.
It can be gradually restored to atmospheric pressure by introducing nitrogen or other inert gases.
Take out the sample:
Under normal pressure, turn on the freeze dryer and gently remove the sample to avoid being affected by external moisture.
For samples that are prone to moisture absorption or oxidation, they should be packaged or stored immediately.
5. Cleaning and maintenance
Cleaning equipment:
After each use, promptly clean up any residual samples and maintain cleanliness both inside and outside the equipment.
Regularly inspect and clean the cooling system and vacuum pump to ensure their normal operation.
Regular maintenance:
Regularly conduct comprehensive inspections and maintenance of low-temperature freeze dryers to ensure long-term stable operation of the equipment.
Replace worn parts, check the sealing ring and coolant condition.
6. Safety precautions
Wear protective equipment:
During the operation, wear appropriate protective equipment such as gloves and goggles to protect yourself from low temperatures and chemical hazards.
Pay attention to the risks of high pressure and low temperature:
Pay attention to the high-pressure and low-temperature components of the freeze dryer during operation, avoid direct contact, and prevent frostbite or burns.
summary
The operation of the low-temperature freeze dryer requires careful adherence to the steps and precautions to ensure the quality of the samples and the safety of the equipment. By reasonable operation and maintenance, the service life of equipment can be effectively extended and the success rate of experiments can be improved.