The detailed steps of freeze-drying Chinese medicinal materials can be summarized as follows:

1. Prepare materials

Cleaning: Thoroughly clean the Chinese medicinal materials that need to be dried to remove surface dirt, impurities, and excess moisture.

Preprocessing: Necessary preprocessing is performed based on the shape and size of the medicinal herbs, such as slicing, sectioning, or crushing, to facilitate subsequent drying and storage.

2. Pre freezing treatment

Placement: Place the pre processed Chinese medicinal materials evenly in the pre freezing chamber of the freeze-drying machine.

Set parameters: Set appropriate pre freezing temperature and time based on the type and characteristics of the medicinal herbs. The pre freezing temperature is generally below -40 ° C, and the time depends on the size and thickness of the medicinal herbs.

Start pre freezing: Start the freeze dryer and perform pre freezing treatment. During the pre freezing process, it is necessary to closely monitor the condition of the medicinal herbs to ensure that the internal moisture of the herbs is fully frozen.

3. Sublimation drying

Transfer: After pre freezing, quickly transfer the medicinal materials to the freeze-drying warehouse.

Set parameters: Based on the characteristics and drying requirements of the medicinal herbs, set appropriate sublimation drying temperature, pressure, and time. The sublimation drying temperature is generally maintained below -25 ° C, and the pressure drops to 66-133 Pa.

Start drying: Start the freeze dryer and perform sublimation drying treatment. During the drying process, it is necessary to regularly check the temperature and pressure changes inside the freeze-drying chamber to ensure the drying effect.