Nanjing Huozao Machinery Technology Co., Ltd. is one of the leading manufacturers and suppliers of double cone rotary dryer in China. With abundant experience, we are committed to providing high quality equipment made in China with competitive price. Welcome to wholesale customized double cone rotary dryer from our factory.
Working Principle
Simultaneous rotation, vacuuming, and heating.
Dynamic Mixing: The main body of the double cone rotary dryer is a double-cone shaped tank that rotates slowly during operation. This continuously agitates the material inside, constantly renewing the surface in contact with the heated inner wall.
Low-Temperature Evaporation: A vacuum pump evacuates the tank to a vacuum state (pressure can reach -0.09MPa to -0.095MPa). Under low pressure, the boiling point of water is significantly reduced, allowing the moisture or solvent in the material to vaporize rapidly without high temperatures.
Indirect Heating: The heat source is introduced into the jacket of the tank, and heat is indirectly transferred to the material through the inner wall of the tank, without direct contact with the heat medium.
Features
During vacuum drying, the pressure inside the cylinder remains lower than atmospheric pressure. This results in fewer gas molecules, lower density, and lower oxygen content, making it effective for drying easily oxidized pharmaceuticals and reducing the chance of material contamination.
Since the temperature of moisture is directly proportional to the vapor pressure during vaporization, moisture in the material vaporizes at low temperatures during vacuum drying, achieving low-temperature drying. This is particularly suitable for the production of heat-sensitive pharmaceutical materials.
Vacuum drying eliminates the surface hardening phenomenon that easily occurs during atmospheric pressure hot air drying. This is because the large pressure difference between the inside and surface of the material during vacuum drying causes moisture to quickly move to the surface under the pressure gradient, preventing surface hardening.
During vacuum drying, the small temperature gradient between the inside and outside of the material allows moisture to move and be collected independently due to reverse osmosis, effectively overcoming the loss phenomenon caused by hot air drying.
Technical Specifications and Selection Reference
|
key parameter |
Typical values/ranges |
Explain |
|
Loading coefficient |
20%–50% (based on tank volume) |
This is a very important parameter; it should generally not exceed half of the tank's volume to ensure that the material has sufficient agitation space. |
|
Heating temperature |
Shell temperature ≤ 140 °C (depending on the heating method) |
Low-temperature drying is achieved by controlling the temperature of the heat transfer medium, thereby protecting heat-sensitive materials. |
|
Working vacuum level |
Tank interior: -0.09 to-0.096 MPa |
The higher the vacuum level, the lower the boiling point of water, and the faster the drying rate. |
|
Tank rotation speed |
3–12 rpm (higher-speed for large equipment) |
The rotational speed directly affects the material agitation and mixing performance; it is typically either non-adjustable or only fine-tunable. |
Applications
The double cone rotary dryer is suitable for vacuum drying and mixing of powdered and granular materials in the pharmaceutical, food, and chemical industries. It is especially suitable for materials with the following requirements:
1. Heat-sensitive materials that cannot withstand high temperatures;
2. Materials that are easily oxidized or hazardous;
3. Materials requiring solvent and toxic gas recovery;
4. Materials requiring extremely low residual volatile matter content;
5. Materials requiring thorough and uniform mixing.
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