Evaporator for heat sensitive products

The removal of solvents when making products in industries like food, cosmetics, pharma and fine chemicals if often a sensitive chapter in the production process. If the solvents aren’t removed at the correct low temperature, it could have a negative impact on the color or flavor of the end product. For active ingredients, like proteins in food products, a high temperature could even lead to loss of nutrient value.

Concentrating products with steam and rotation, under vacuum

The Evapor by Okawara is a single effect, thin-film centrifugal evaporator that works under vacuum. For the concentration of heat sensitive products, viscous products, products that tend to foam and other high value products, this equipment is a good fit. The system consists of a hollow disc cone, rotating on a horizontal cantilevered shaft, using steam as a heating medium. The material that needs to be concentrated is pumped into the machine with a feed tube to have it transported to the bottom of the rotating spinning cone. Centrifugal force spreads the liquid over the heating surface in a thin layer of less than 0,1 millimeter. It passes across the heating surface in less than one second. The material like a fruit juice, dairy or other cosmetic, pharma or chemical products, is heated to the boiling point. This is controlled by the vacuum in the system. The concentrated material is then collected on the outskirts of the spinning cone by a paring tube. The product vapor will flow to a condenser where it will condensate and discharged by a pump.

The machine has a comparatively small heat transfer surface in relation to its heat transfer capacity. This results in a compact design that still has the capability to evaporate more water per unit area and doing so in less time than a more traditional evaporator. Additionally, the application of centrifugal force also helps to minimize generation of foam in a more effective way than falling film or scraped film evaporators. The evaporation temperature is between 35 to 90 C. Operating pressure is between 5,5 to 78 kPa/ 0.055 to 0.78 bar. The heating temperature can be between 60 to 100 C. Evaporation capacity is between 30 to 1,200 kilos per hour.


  • Capacity to handle several viscous products
  • Foam generation minimized by centrifugal force
  • Hygienic design for cleanability