Buss-SMS-Canzler GmbH

The pressure difference between the boiling film and the condensing surface is the driving force for the vapour flow. Operating below 1 mbar requires extremely short distance between the boiling surface and the condensing surface to minimise the pressure drop caused by the vapour flow. For this reason one also talks of Short Path Distillation, High Vacuum Evaporation or Molecular Distillation. The short path evaporator has an internal condenser opposite the heated surface enabling operations down to 0.001 mbar.

Our short path evaporators are characterised by its sturdy construction and the special rotors. The rotors will process products with demanding properties with regard to high viscosity, high boiling temperature and suspended solids.

Operating Principle of short path distillation
Short path distillation is a thermal separation technique operating at a process pressures in the range of 1 to 0,001 mbar. It lowers the boiling temperature and is an excellent method for gentle thermal treatment of heat sensitive, high boiling products. The Short Path Evaporator consist basically, of a cylindrical body with a heating jacket, a rotor and condenser inside. On the supporting structure of the rotor mobile precision wiper blades are mounted. They are forced by centrifugal force to fold open in direction of the inner shell and are pressed against this.

Short path evapoartor cross section, highlighting the principle of of short path distillation, molecular distillation

The wiper blades creates a mechanically agitated, thin product film on the heating surface inside of the body. By means of gravity the product flows in a spiral path downwards, whereby the volatile portion of the product evaporates.

The vapour passes by the shortest route and with practically no pressure drop to the internal condenser where it is recipitated on the tubes. The non-volatile portion reaches the lower part of the evaporator and leaves it through the bottom product outlet. The residual vapours and inert gases flow through the vacuum nozzle to the vacuum system.

Typical applications of short path distillation
The short path evaporator is specifically well suited for distillation, evaporation, concentration and stripping of products with the before mentioned properties. The applications listed below are just some typical ones:

• Stripping Isocyanates from Prepolymers
• Stripping Cycles from Silicone Oils, Resins and Polymers
• Evaporation of Oil and Wax Fractions from Petroleum
• Fractionating of Waxes into hard and super hard Waxes
• Stripping Solvents and Dimers form all kind of Resins
• Distillation of Monoglycerides from Di- and Triglycerides
• Concentration of Omega-3-fatty acids
• Evaporation of Methylester
• Concentration of Vitamin-E, (Tocotrienol & Tocopherol)