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Features and Working Principle of Vacuum Dryers

Oct. 20, 2021
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The use of vacuum to assist or achieve complete drying is not a new concept. The reduction in air pressure lowers the boiling point of water and other liquids, thereby accelerating their evaporation. Vacuum drying is still a viable alternative in some specific applications and WANTONG gives you an overview of its principles and advantages.


Vacuum drying

Drying is the process of removing water or solvents by an evaporation process; the output of the dryer must therefore be a solid material in any particular structure or powder form. In order to achieve a dry output, heat is applied to evaporate the water or solvent.


Drying thermosensitive materials

If heat is applied to evaporate the water or solvent contents, the material itself will be harmed as a heat-sensitive material and therefore special provisions are required to dry such heat-sensitive materials. In order to dry such heat sensitive materials, the ambient pressure needs to be reduced as water and many solvents reach their boiling point at lower temperatures and at lower pressures, hence the name vacuum drying . The combination of heat and vacuum has proven to be a very effective source of drying at relatively low temperatures and the moisture content in materials dried by vacuum dryers is lower than that of ordinary dryers, those that do not use vacuum.


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Low temperature vacuum dryer dehydrator


Suitability

Vacuum drying is often used for relatively small parts with small surface features or other properties that make it difficult to dry using other means. In most cases, parts retain relatively little moisture - of course, parts with "puddles" are not suitable for vacuum drying.

In most cases, the required heat is provided in the form of radiant heat from a heater in the vacuum chamber or by heating the chamber with an external device. Some vacuum drying equipment even has heated racks on which parts can be placed, although this is more suitable for powders.

We at WANTONG specialise in the manufacture of superior quality, customised vacuum dryers, including the CT-C hot air circulation dryer, DW belt dryer, ZG vibrating fluid bed dryer, GFG vertical fluid bed dryer and liquid spray dryers.


Advantages

Vacuum dryers are very effective for heat sensitive

Material can be a container or a dryer in a shell

Average drying temperatures are much lower than standard dryers 

Drying action becomes faster and heat is easily transferred to the entire body of the dryer

Large amounts of moisture can be dried compared to a conventional dryer 

Dries material of better quality than ordinary dryers


Limitations

The vacuum drying process is intermittent and inefficient.

Vacuum dryers are expensive and have high maintenance costs.

Vacuum dryers require skilled labour to operate.


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Low Temperature Double Cone Vacuum Dryer


Vacuum dryers can be used in a variety of industries such as chemical processing industries, food processing, pharmaceuticals, plastics, wood, paper, etc. If you have a purchase to make, please contact us or call +86 139 2120 9007. Our experts will be happy to advise you on your production.


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