How to choose vacuum pump of freeze dryer
With the continuous development of freeze dryer, it is more and more attention, its function is more and more perfect. In addition, after freeze-drying, the volume and shape of the product are basically unchanged, and the material is in the dry powder state without drying shrinkage. Laboratory applications cover common laboratory products to meet daily needs and ensure product quality.
Vacuum freeze-drying is to freeze the material containing a large amount of water into a solid by pre cooling, and then sublimate the water vapor from the solid directly under certain vacuum conditions, while the material itself remains in the frozen ice shelf, so its volume remains unchanged after drying, and it is porous. When ice sublimates, it needs to absorb heat, which causes the temperature of the product to drop, which reduces the sublimation speed. In order to improve the sublimation speed and shorten the drying time, the product must be heated properly. The whole drying process was carried out at a lower temperature.
The function of vacuum pump is to remove gas molecules from the vacuum chamber and reduce the gas pressure in the vacuum chamber to achieve the required vacuum degree. Vacuum pump is more and more widely used in laboratory. The vacuum pump can be used with other instruments instead of a single device. Vacuum pump is an indispensable auxiliary equipment in every laboratory. The application of different instruments and equipment has different requirements for vacuum pump.
Dry vacuum pump, also known as oil-free vacuum pump, depends on the parts of the machine to achieve the required vacuum, without pollution and maintenance. Oil free piston type (mainly used in microbiological laboratory) and corrosion-resistant diaphragm type (mainly used in chemical laboratory) are used in laboratory.
Non dry vacuum pump can be divided into oil vacuum pump and water circulation vacuum pump. The common point of non dry vacuum pump is that water and oil are needed to achieve the ideal vacuum degree. The commonly used pump in laboratory is oil rotary vane pump, which is usually used with laboratory freeze dryer and vacuum dryer.
The selection of vacuum pump for freeze-drying machine should first understand the use of vacuum pump and whether the extracted gas is corrosive. Generally, considering the configuration of vacuum pump in other instruments and equipment, oil-free vacuum pump can be selected for sample filtration.
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