The basic principle of a freeze-drying machine is based on the three state changes of water. Water can be in solid, liquid, and gas states, and this device has three phases that can both be converted and coexist. When water is at the triple point (temperature is 0.01 ℃, water vapor pressure is 610.5Pa), water, ice, and water vapor can coexist and balance with each other. In a high vacuum state, using the sublimation principle, the moisture in the pre frozen material is directly sublimated into water vapor without melting the ice, thus achieving the purpose of freeze-drying.
Simply put, the principle of a freeze-drying machine is to place the sample in a vacuum environment through a process from high to low temperature, allowing the free water in the sample to evaporate. The bound water in the sample cannot evaporate, with the aim of increasing the sample's storage time.
Introduction to freeze-drying machine:
Freeze dryer is the abbreviation of vacuum freeze-drying machine, also known as freeze-drying machine in the industry. It is a stable material drying equipment, divided into biopharmaceutical freeze-drying machine, industrial freeze-drying machine, food freeze-drying machine, and laboratory freeze-drying machine. Due to the fact that substances are preserved in their original properties and mechanisms after freeze-drying, their color, shape, etc. remain basically unchanged and can be stored for a long time at room temperature, freeze-drying machines are widely used in drying treatments such as pharmaceutical freeze-drying, food freeze-drying, biological product freeze-drying, microbial freeze-drying, industrial material freeze-drying, cultural freeze-drying, etc.
Composition of freeze-drying machine:
The freeze-drying machine mainly consists of the following components: compressor, refrigerant, oil separator, condenser, drying filter, intercooler, sight glass, solenoid valve, hand valve (top cover valve), expansion valve, evaporator (plate heat exchanger, rear box condenser coil), vapor-liquid separator, return air filter, pressure gauge, pressure control relay, CPCE (energy regulator), safety valve, refrigeration pipeline, etc.
Precautions for freeze-drying machine:
Before each startup, first check if the pump oil in the vacuum pump is sufficient.
Unscrew the drainage valve to allow any remaining water inside to flow out. After draining, tighten the valve again.
Check if the contact between the freeze-drying chamber and the cold trap is intact, clean and readjust if necessary.
Close all valves (the valve directly connected to the freeze-drying bottle is closed when the white knob is turned up). Close the valve that connects the cold trap to the vacuum pump (located behind the instrument and connected to the vacuum tube).
Turn on the power switch of the cold trap and the power switch of the vacuum pump.