Views: 2 Author: Site Editor Publish Time: 2025-08-28 Origin: Site
In industries such as pharmaceuticals, chemicals, and food, vacuum drying technology is highly favored for its ability to efficiently dry materials at low temperatures, preventing damage to heat-sensitive substances. Many companies opt for the traditional rotary vacuum paddle dryer (RVPD) due to its simple structure and stable performance. Meanwhile, some hot air dryers, such as centrifugal spray dryers, are also widely used for their high drying efficiency. However, their high energy consumption is a persistent challenge for many manufacturers.
As production demands evolve, factories increasingly seek more efficient and energy-saving alternatives. To address this, our company’s founder, Mr. Gu invented the Hollow Screw Vacuum Dryer, which combines the advantages of the rotary vacuum paddle dryer (RVPD) while offering significant improvements, achieving higher drying efficiency.
Similar to the rotary vacuum paddle dryer (RVPD), the core of the Hollow Screw Vacuum Dryer lies in its multi-source heat conduction and dynamic mixing under a vacuum environment. In a vacuum, the boiling point of water or solvents in the material is lowered, enabling evaporation at lower temperatures. After the material enters the drying chamber, heat is transferred through contact with heating surfaces through which hot water, steam, or thermal oil flows.
The rotary vacuum paddle dryer primarily relies on the jacketed inner wall of the drying chamber for heat transfer. Although its rake agitator also has a heating function, the heating surface area is limited, serving mainly to assist in stirring. This can lead to uneven mixing, resulting in inconsistent drying.
In contrast, our Hollow Screw Vacuum Dryer features a “triple heating” design, where the hollow screw structure, main shaft, and chamber walls can all be heated by the heat source. As the screw blades and main shaft rotate, they continuously turn and advance the material, ensuring uniform heat distribution and achieving even, rapid drying.
Efficiency is a critical factor in production. The Hollow Screw Vacuum Dryer primarily conducts heat through the screw blades’ heating surfaces. As the material moves with the screw inside the chamber, it fully contacts the heat source, enabling drying without dead zones. This makes it particularly suitable for large-scale production.
In contrast, the RVPD’s reliance on the chamber’s jacket for heating offers a limited heating area, resulting in longer drying times and lower efficiency. Extensive testing with various materials has shown that, under identical drying conditions, the hollow screw vacuum dryer achieves drying efficiency 3–5 times higher than that of the RVPD.
The hollow screw vacuum dryer offers flexible loading options, allowing loading by opening the cover or through the feeding port. It accommodates various material forms, such as powders, liquids, granules, or slurries. In contrast, the RVPD typically supports only feeding port.
Our dryer’s open-cover design provides full visibility of the chamber’s interior, enabling thorough and convenient cleaning to prevent contamination—a critical feature for the pharmaceutical and food industries. Most RVPD can only be cleaned from the feeding port, and while some allow side-door cleaning, they still have dead zones where residual material is difficult to remove completely, posing a contamination risk.
The lid can be opened,feeding can be done either by opening the lid or through the feeding port, and easy to clean,no dead corners
Feeding can only be done through the feeding port. Although cleaning can be done from the side, there are still dead corners
Many materials requiring vacuum drying must be cooled to a specific temperature or protected from oxygen exposure before discharge, necessitating cooling under vacuum conditions after drying. The hollow screw vacuum dryer facilitates rapid cooling by circulating a cooling medium through the screw blades, main shaft, and chamber walls. Similar to its heating mechanism, the “triple cooling” design significantly outperforms the RVPD, greatly enhancing production efficiency.
Beyond these design features above, our hollow screw vacuum dryer also offers significant benefits in energy consumption ,solvent recovery and application. If you’re interested, we invite you to contact us for material testing!
Contact: info@machtechdryer.com
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