During the use of a vacuum freeze-drying machine, it is usually necessary to release air first and then turn off the vacuum pump, in order to protect the vacuum pump and improve the drying effect.

Firstly, the purpose of venting is to eliminate gases and vapors that may be generated during the freeze-drying process. During the freeze-drying process, the water in the sample will be transformed into ice and directly transformed into a gaseous state under vacuum conditions, which is called sublimation. At the same time, other gases, volatile substances, or solvents in the sample may also evaporate at low temperatures, forming gases. If these gases and vapors are not eliminated in a timely manner, they can affect the vacuum degree and even have a negative impact on the vacuum pump.

Secondly, venting before turning off the vacuum pump can protect its lifespan and performance. After long-term operation, a vacuum pump will generate certain wear and heat. If the vacuum pump is directly turned off without first venting, it will cause a sudden increase in internal pressure, which may have adverse effects on the sealing components and internal structure of the pump, and even cause malfunctions. By first venting and then turning off the vacuum pump, the pressure can gradually be restored to atmospheric pressure, reducing the impact on the vacuum pump and extending its service life.

Overall, venting before turning off the vacuum pump is to protect the vacuum pump and improve drying efficiency. This is a routine operation step in the vacuum freeze-drying process to ensure the stability, safety, and durability of the system. During the operation process, please follow the instructions and operating specifications of the equipment to ensure the effectiveness of the laboratory and the normal operation of the equipment.