The process is very important in the freeze-drying process of the four-ring freeze-drying experimental freeze-drying machine

The four-ring freeze-drying experimental freeze-drying machine is also called sublimation drying
.

The principle is to freeze the material so that the water contained in it becomes ice cubes, and then sublime the ice under vacuum to achieve the purpose of drying
.

Freeze drying refers to the process of removing moisture or other solvents from frozen biological products through sublimation
.

Sublimation refers to the process by which a solvent, such as water, changes directly from a solid state to a gaseous state without going through a liquid state, like dry ice
.

The product obtained by freeze-drying is called lyophilisate, and the process is called freeze-drying
.

Traditional drying can cause the material to shrink, destroying cells
.

The structure of the sample is not destroyed during freeze-drying because the solid components are supported by the solid ice in their place
.

As ice sublimates, it leaves pores in the dry leftover material
.

This preserves the integrity of the product's biological and chemical structure and its activity
.

Four-ring freeze-drying experimental freeze-drying machine freeze-drying sample operation process: 1.
Sample placement: a.
Place the pretreated items in the material tray, and then put the material tray in the freeze-drying rack
.

b.
Place the temperature sensor in any layer of material tray to measure the temperature of the material
.

c.
Put the freeze-drying rack into the cold trap, cover the insulation cover, and prepare for pre-freezing
.

2.
Pre-freeze the sample a.
Turn on the main power switch on the back of the device
.

b.
After clicking the screen to enter the interface, click the "Refrigerator" button to start the pre-freezing.
It is recommended to pre-freeze for about 4 hours
.

c.
After the items are completely frozen, remove the freeze-drying rack from the cold trap
.

3.
Sample drying a.
Take the freeze-drying rack out of the cold trap, then place the freeze-drying rack support plate on the cold-trap port, place the freeze-drying rack on the support plate, or place the material tray on the freeze-drying rack.
The freeze-drying rack is placed directly above the cold trap
.

b.
Place the probe on the material tray of any layer and cover it with a glass cover
.

c.
Tighten the drain air valve
.

d.
Click the "vacuum gauge" button on the screen, the screen shows that the vacuum degree is 110KPa, and then click the "vacuum pump" button to turn on the vacuum pump
.

The degree of vacuum drops rapidly, until the degree of vacuum is less than or equal to 10Pa, which is normal, and the drying officially begins (it is recommended to dry for about 20 hours, depending on the moisture content of the material, which is determined by the user)
.

4.
Take out the sample a, check the sample curve, and visually check that the sample is completely dry.
After opening the drainage and inflation valve, click the "vacuum pump" button, and the vacuum pump will stop running
.

Click the "Vacuum Gauge" button to turn off the vacuum gauge
.

b.
Remove the glass cover, take out the material tray from the freeze-drying rack, and pack the samples in the tray
.

Click the "Refrigerator" button to turn off the compressor and the device stops running
.

5.
Shutdown operation a.
Turn off the main power switch, and the control system of the whole machine is powered off
.

b.
Unplug the power plug and vacuum pump plug
.

c.
Wipe the cold trap, freeze-drying rack, tray and glass cover with a soft cloth
.

d.
When the vacuum pump is not working, please cover the exhaust hole to prevent dust from entering
.

6.
Drainage operation a.
After the ice condensed on the inner wall of the cold trap is completely melted into water, unscrew the drainage and inflation valve to discharge the condensed water
.