Low Temperature Vacuum Evaporator

The low temperature vacuum evaporator vaporizes water at lower temperature around 40 Deg. C than normal 100 Deg. C due to vacuum. Hence vacuum evaporators are useful for

  • Recovery of heat sensitive chemicals such as cyanide plating baths
  • Recovery of chemicals sensitive to air oxidation such as cyanide plating bath and Stannous tin bath
  • Recovery of solutions containing volatile components

Working Principle

The low temperature vacuum evaporator mainly consists of an evaporator tank 2, evaporator heat exchanger 4, process water circulation pump 3, refrigerant compressor 8, condenser heat exchanger 7, distillate tank 11, vacuum producing venture 13, and distillate circulating pump 12. The feed water enters the evaporator tank 2, and the feed water is circulated by the pump 3 to evaporator heat exchanger 4, where the feed water is heated by high pressure refrigerant from the refrigerant compressor 8. The hot water flashes as water vapor into the evaporator tank at the top. This water vapor passes through the mist eliminator 16 and the condenser heat exchanger 7. The refrigerant from the evaporator heat exchanger passes through air cooler and expansion valve and becomes cool liquid. The cool refrigerant cools the hot water vapor to distillate. The distillate is collected in the distillate tank. The distillate is circulated by the distillate circulation pump through a venture, which produces vacuum in the evaporator tank. The vacuum produced by the venturi in the evaporation tank causes process water boils between 40 to 50 Deg. C. The concentrated process water from the evaporator tank and the distillate from the distillate tank are automatically drained by the electrical controls. All necessary controls and switch gears are part of the system.

Advantages and features

  • Independent of Solution Heating Requirements
  • Less or No Air Pollution
  • Can handle Heat Sensitive Compounds
  • Carbonates do not build up scales as with other evaporators


  • Concentration of Liquids from Finishing Processes
  • Concentration of Oily Emulsions
  • Concentration of Wash Baths
  • Recovery of Metals from Rinse Waters (chromium, nickel, copper)
  • Concentration of contaminated Baths from Degreasing and Pickling
  • Recovery of Tempering Salts
  • Purification of Wash Waters
  • Recovery of Gold from the Residue of the Treatment Process
  • Concentration of working Liquids in Die Casting units a (detaching   product, glycol, lubricants)
  • Recovery of food additives from different Industrialprocess Liquids
  • Recovery of Proteins from Whey
  • Recovery of solvents utilized for Extraction Process
  • Concentration of Phosphoric Degreasing Baths
  • Recovery of Vulcanizing Salts