Short path evaporator

We design short path evaporators to separate a multitude of mixtures and especially for molecular distillation and purification of extremely heat-sensitive substances and products with a very high boiling point.

Short path evaporators consist of a cylindrical, heated, vertical vessel and a high-speed rotor that maintains a film of product against the heated wall in highly turbulent conditions. A high evaporation rate and short contact time are achieved making processing also the most thermal sensitive products possible.

Moreover, there is an internal condenser, mounted coaxially to the rotor, that reduces the distance between the heating and condensing surfaces, limiting pressure loss and permitting operations under extreme vacuum conditions and, consequently, at low process temperatures.
The overall result is the best solution for a gentle separation, required in many fields.


Features and options

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  • Standard sizes from 0,05 m2 to 55 m2, smaller and larger depending on process needs
  • Feed flow from 0,1 t/h to 25 t/h
  • Operating pressure from 0,001 mbarg to 10 mbar
  • Wide range of temperatures depending on the product limitations and operating pressure
  • Compatible with various types of heating media (steam, hot oil and hot water)
  • No recirculation
  • Heat recovery configuration


  • Contacting type rotors (P, PHV types): wiped blade type rotors in contact with the heated surface

The most suitable material is selected depending on the nature of the process stream, wastewater and operating conditions.
The main materials usually selected are the following:

  • Glass lined carbon steel
  • 316L stainless steel
  • Super duplex stainless steels
  • Nickel alloys (e.g., Hastelloy® HC22)
  • Titanium

Configurations to optimise energy consumption are as follows:

  • Using hot water from cogeneration
  • Using waste energy (e.g., exhaust gas, steam condensate, process condensate)
  • Combining the abovementioned technologies

To learn more about our design, production and service capabilities check the DBO section.


  • Heating

  • Cone:
    • Simple, non-heated
    • Simple, heated (refer to heating options)
    • Simple, heated and scraped
  • Double cone

  • Driving group motor configurations:
    • Coaxial gearbox
    • Parallel gearbox
    • Orthogonal gearbox
  • Driving group shaft seal:
    • Double wet mechanical seal
    • Using 2 bearings and a longer shaft to increase stiffness to the rotor, even without a lower support (pin bushing or pin bearing)


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  • Bottom guides with lubrication package upon request:
    • Pin and bearing
    • Spider
  • Condenser:
    • Shell and tube type
    • Mixing type
    • Cold traps
  • Vacuum pump (selected based on process pressure operating range)
  • Chilling units
  • Inverter
  • Cleaning features:
    • Flooding
    • Spray nozzles


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Thanks to the various features and options and our many years of process expertise in thermal separation, our short path evaporators are used across multiple industries in a wide range of applications in industrial processing, especially to concentrate and purify thermal sensitive products, including waste recovery.

They are optimally suited to handle very complex mixtures with different properties, such as:

  • Viscosity: low to very high
  • Temperature sensitivity: very high
  • Boiling point: medium to very high
  • Fouling: low to high
  • Foaming: low

Short path evaporators can be provided as a standalone operation unit or, as the majority of applications require, as part of a plant consisting of several units, including other evaporator types. They are often used as a last stage in combination with a thin film evaporator.

More about plants

More about processes

For new or innovative applications or to assess the correct sizing even for consolidated processes, we can provide support to customers with software simulations and testing operations, determine which type of evaporator (or which plant concept) is the most suitable for the performances sought.

More about R&D

Want to know more about the short path evaporator?

Contact us