Continuous paddle dryer

The continuous paddle dryer is a high-speed horizontal indirect dryer/cooler suitable for heating and drying slurry, filter cakes, pastes, powders and granulates. It has a patented jet rotor design that allows injection of a gas or liquid through the paddles into a thin layer of material as it spirals along the cylindrical wall of the unit. It can be designed for use with a variety of heat sources and has a vast number of applications. It's fast and very effective.

The continuous paddle dryer also processes heat-sensitive materials ranging from free-flowing solids to wet cakes and slurries.

Continuous paddle dryer Continuous paddle dryer Continuous paddle dryer

The wet product is fed into the dryer using a dosing device. This dosing device should be selected based on the characteristics of the product. The product is then centrifuged in a thin layer and heated by the jacketed vessel.

The continuous paddle dryer has three operating modes:

  1. Indirect heat transfer, where heat is conducted through the cylindrical housing. This thermal processing method is well suited to solvent evaporation processes where a small counter-current flow of an inert sweep gas increases the rate of mass transfer.
  2. Direct heat transfer: thermal processing in which heat is transferred by convection using a large volume of gas. Direct heat transfer is applied using a co-current flow of material and gas. The two components are separated downstream in a cyclone or bag filter.
  3. A combination of indirect and direct heat transfer can be used to optimise energy efficiency while also reducing the material temperature.

The jacket can be split into several sections, each with its own different temperature. The direct air is used to strip the solvent away of the dryer and the wet product is dispersed and reduced in size with the high speed of rotation. This causes the surface area of the product to increase and water (or other solvents) to evaporate instantaneously. The dry and fine product is carried out through the outlet valve.

An exhaust fan keeps the system under negative pressure and the continuous paddle dryer has a mechanical agitator in a cylindrical, jacketed housing designed with a large number of narrow, flat, adjustable pitch paddles for sweeping closely to the inside of the housing. Residence time can vary from seconds to approximately 20 minutes by adjusting paddle pitch and rotor speed.

This unique technique disperses liquids quickly and transforms products such as filter cakes, slurries from centrifuges, wet solids from decanters and press cake after press filtration into dry powders.

Applications for the paddle dryer include:

  • Cooking
  • Sterilising
  • Drying
  • Heating
  • Cooling
  • Reacting
  • Coating
  • De-agglomeration
  • And combinations of the above

Different sources of heat can be used depending on the application, for example:

  • Hot air: either directly heated by gas burning or through a heat exchanger
  • Nitrogen: closed loop for explosive materials
  • Superheated steam: for higher capacities and sterilisation of products 


  • High heat transfer due to high paddle speed
  • Nearly plug flow process
  • Suitable for close-loop operation (e.g. solvent-recovery)
  • Variable residence time from seconds to approximately 20 minutes
  • Different temperature for different sections of the jacketed vessel

The continuous paddle dryer is available in many sizes. A few sizes with their typical characteristics are described below. Please note that these values are indicative only. Detailed information is available on request.

Model (Ø - L) [m] 0.20 - 1.25 1.00 - 7.10 2.24 - 15.00
Heat transfer area [m²] 0.7 19 107
Cross section area [m²] 0.03 0.52 2.30
Max. power installed [kW] 4 75 200
Max. rotor rotation speed [r/min] 1520 310 100

Our expert design and engineering team will happily help you specify the right ancillary equipment to compliment your continuous paddle dryer(s). These ancillaries may include:

  • Special feeding units
  • Air heaters 
  • Dust collectors
  • Ventilators
  • Plant controls including PLC and PC

How can we help you?

To learn more about our powder process equipment, contact us:

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Hosokawa Micron B.V. is a process machinery supplier, providing mixing, drying and agglomeration equipment and systems for the powder and bulk processing industry.


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