Vacuum freeze-drying needs to be carried out in a certain device, which is called a vacuum freeze-drying machine or a pilot freeze-drying machine, abbreviated as a freeze-drying machine.

The Shanghai Yetuo freeze-drying machine is divided into four main parts according to the system: refrigeration system, vacuum system, heating system, and control system. Divided by structure, it consists of a freeze-drying oven or drying oven, a condenser or water vapor condenser, a refrigeration unit, a vacuum pump and valve, electrical control components, etc.

A freeze-drying box is a high and low temperature box that can be cooled to around -55 ℃ and heated to around+80 ℃. It is also a sealed container that can be evacuated. It is the main part of the freeze-drying machine. The products that need to be freeze-dried are placed on the layered metal plates inside the box, frozen, and heated under vacuum to sublime the moisture inside the products and dry them.

The condenser is also a vacuum sealed container with a large surface area for metal adsorption inside. The temperature of the adsorption surface can be lowered to below -40 ℃ to -70 ℃ and maintained within this low temperature range. The function of the condenser is to freeze and adsorb the water vapor sublimated from the product inside the freeze-drying box onto its metal surface.

The vacuum system of the freeze-drying machine is composed of freeze-drying box, condenser, vacuum pipeline, valve, vacuum pump, etc. The vacuum system requires no air leakage, and the vacuum pump is an important component for establishing vacuum in the vacuum system.

The refrigeration system consists of a refrigeration unit, a freeze-drying box, and pipes inside the condenser. Refrigeration machines can be two or more independent sets, or they can be used together in one set. The function of a refrigeration machine is to cool the freeze-drying box and condenser to generate and maintain the low temperature required for their operation. It has two methods: direct refrigeration and indirect refrigeration.

The heating system has different heating methods for different freeze dryers. Some use direct electric heating method; Some use an intermediate medium for heating, with a pump (or an additional backup pump) continuously circulating the intermediate medium. The function of the heating system is to heat the products inside the freeze-drying box, so that the moisture inside the products continuously sublimates and meets the specified residual moisture content requirements.

The control system consists of various control switches, indicating and regulating instruments, and some automatic devices. It can be simple or complex. Generally, freeze-drying machines with high levels of automation have more complex control systems. The function of the control system is to manually or automatically control the freeze-drying machine, operate the machine normally, and produce products that meet the requirements of the freeze-drying machine.