Conical Dryers

Conical Dryers, Conical Reactors, Conical Evaporators, Helical Dryers

AVA Conical drying mixers are suitable for a wide range of drying and evaporation processes in batch operation. They consist of a cone-shaped vessel with mixing helix installed close to the side walls. They were developed for shorter process times with maximum product protection.

The mixing helix is a double-threaded (or single) conical spiral that is connected to the shaft via steps. It conveys the product upwards along the heated side wall, after which it sinks downwards again inside the process chamber. This results in a uniform temperature and product humidity across the entire product chamber. To further reduce the drying time, the helix can additionally be heated and a vacuum can be applied. In the convective heating variant, steam or hot air is applied to the mixer interior, and the drying elements can also be heated.


AVA conical drying mixer application scenarios range from laboratory to large-scale production, and from highly sensitive pharmaceutical applications to rugged environmental engineering. Customers frequently chose this versatile machine type as the basis for tailored solutions. This is a tiny sample of the possible applications: drying of APIs for the pharmaceutical industry, sterilizing of spices in the food industry, drying of ion exchange resins in the chemical industry, the evaporation of solvent-containing sludge in environmental engineering, as well as coating of iron powder with additives in metallurgic applications. A multitude of process steps can be implemented using AVA conical drying mixers.

System Characteristics
  • Self-centering helix design with single-side bearing
  • Particularly gentle and fast homogenizing thanks to double-action mixing helix
  • Drive and bearings outside of the mixing chamber prevents risk of product contamination due to lubricants, amongst others
  • Sealing external to mixed/dried product significantly reduces maintenance costs
  • Drying temperatures from –20°C to 800°C
  • Temperature transfer via double jacket, half pipe, shaft, and helix
  • Larger heating surface design for shorter drying times
  • Above-average heat transfer through continuous mixing and intensive product contact with the heated side wall
  • Heating media: steam, thermal oil, water, or electrical heating for high-temperature applications, coolant: brine solution or water
  • Pressure in product and heat chamber: -1 bar to +40 bar
  • Materials: carbon steels through to high-quality stainless steels such as Hastelloy
  • Lower rotation speeds than in other systems
  • Larger operation volume range and optimal residual discharge
  • Very high evaporation capacity – evaporation processes almost continuously controllable
  • High failure resistance and low operating costs compared to conical screw mixers
Versatility through Variants

A multitude of application options facilitate individual solutions, customized to specific needs. Robust machine designs, which are essential for environmental engineering, can be omitted in pharmaceutical applications, FDA-compliant seals, which are essential for the pharmaceutical industry, are not required in environmental engineering designs. The following add-ons are in successful operation in a variety of AVA conical dryers.

  • Design: with single or double helix
  • Special pharmaceutical designs available
  • GMP and CIP designs, FDA, EHEDG, and HACCP compliant
  • Automatable and certifiable CIP cleaning of the closed machine
  • Shaft seal systems variants: stuffing box and shaft seal rings, maintenance-free special lip ring seals, mechanical seals
  • Application of blade head/agglomerate crushers and product-specific blade head variants
  • Product discharge via flap, slide gate, ball segment valve, or ball valve
  • Installation of samplers, temperature probes, and other equipment
  • Delivery of containment systems

We look at all the details and we listen to your input. For a large number of scenarios, we have already come up with the best-of-breed solution. And whenever a new challenge arises, we collaborate with you to develop the right product.

Our AVA test center provides a wide range of machines (horizontal and vertical mixers, horizontal and vertical drying mixers, laboratory mixers, and ring layer mixers) in various sizes, allowing you to carry out scale-up tests. Be it horizontal or vertical, we have extensive expertise in the design of both types. So simply pick the technology that yielded the best results, and we will deliver.

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