The correct selection of agitators for vacuum single-cone dryers

The vacuum single cone dryer is a new type of vacuum drying equipment. With a fully sealed design and indirect material heating method, it is particularly suitable for drying dangerous and toxic materials containing solutions or moisture, and can reduce the humidity to a very low level. Due to the gentle nature of the mixing method, even materials that are sensitive to machinery will not be damaged. After drying, the quality of the material is retained and may even be no less than that of the original material. The demand for driving force is very low. The achievable high vacuum ensures a low drying temperature (which is a significant advantage for heat-sensitive materials), good heat transfer effect and short drying time, while consuming less energy. The directly installed filter will retain dust particles in the process space. Complete and easy unloading enables continuous processing of materials without increasing losses. Not only solids, but the vacuum equipment integrated in the closed system can also cyclically process moisture and solutions.

When designing a vacuum single-cone dryer, one of the important components is its agitator. To select the correct agitator with the right characteristics, it is necessary to understand the properties of the feed and the vacuum drying process results required by the process.

(1) Screw agitator

The screw agitator is a well-proven design suitable for drying powder and non-sticky filter cakes under atmospheric or vacuum conditions. Due to its outstanding performance in conveying products along the container wall, it ensures the realization of an efficient drying cycle and can be applied to dryers with a drying capacity of over 20,000 liters.

(2) Paddle agitator

When the viscosity of the product is relatively low, a paddle agitator can be used to achieve the best temperature control and product transportation between the rotor blade tips and the container walls. When necessary, it can be used to fully mix the product after the drying cycle.

(3) Helical ribbon agitator

The conical helical ribbon agitator is a better alternative to the screw agitator and is suitable for drying powders, filter cakes, pastes and slurries under atmospheric or vacuum conditions. It is almost applicable to all products, even sticky ones. It can stir a larger batch of products at one time, thereby achieving better heat transfer and reducing drying time.

(4) Comparison of Advantages of Internal Heating helical Ribbon agitators - Taking a 2000L dryer of the same volume as an example