As the saying goes, no one is perfect, as long as people have advantages and disadvantages, the machine is also so, vacuum freezing dryer has advantages and disadvantages.
With the development of science and technology, there are many kinds of drying methods, such as drying, air drying, high temperature drying, spray drying and freeze-drying at low temperature.
ordinary drying method (
Such as drying, air drying, high temperature drying and spray drying)
Usually above 0 ℃ or under higher temperature.
Dry the product generally smaller, quality of a material to harden problems, most volatile component is lost, some heat-sensitive material produces denaturation and inactivation, some material even oxidation occurred.
Therefore, after drying products compared with before drying, there's a big difference in character.
and vacuum freeze dryer is lyophilization method at low temperature, its principle is the first to freeze water matter into a solid, then make the moisture from the solid sublimate to gas, and then the method to remove moisture and save material.
from philosophy, positive and negative coexist, superior to domestication, everything is relative.
Vacuum freezing dryer is relatively common drying method, low-temperature freeze-drying method has the following advantages:
1, many heat-sensitive substances will not be buckled or inactivation.
2, dry at low temperature, the material of some volatile component loss is very small.
3, in the process of freeze-drying, the role of the growth of microbes and enzymes to, so can keep the original character.
4, because in the frozen state to dry, so the volume is almost the same, to keep the original structure, enrichment phenomenon will not occur.
5, due to the material in the water after the precool exist in ice crystals form, the original dissolve in the water dissolved inorganic material is evenly distributed in the material.
Sublimation, soluble in water soluble materials are precipitation, general drying method is avoided because of material carried by internal moisture migration to the surface of inorganic salt in the surface precipitation caused by hardening the surface of the phenomenon.
6, after drying of material is porous, the sponge, add water dissolve quickly and completely, after almost immediately restore the original character.
7, due to the drying under vacuum, oxygen is few, so the easy oxidation of some substances have been protected.
8, dry can remove more than 95% ~ 99% moisture content, dry products can be long-term preservation and not bad.
vacuum freeze dryer are the main disadvantages of high cost.
Because it need to vacuum and low temperature conditions, so the vacuum freeze drying machine configuration a set of vacuum system and the cryogenic system, so investment cost and operation cost are high.
Disadvantages: 1, compared to vacuum freeze drying machine dryers, vacuum drying equipment such as the price is higher;
2 and high cost of freeze-drying processing compared with the ordinary way;
