Fundamental:

        The rising film evaporator, also called the long tube vertical evaporator (LTV), or Kestner evaporator, was widely used before the mid-1980s, after which the falling film evaporator took the lead. The principle of the rising film evaporator is shown in the figure below. The heating chamber is composed of single or multiple vertical tubes. The ratio of length to diameter of the heating tube is 100-150, and the tube diameter is between 25-50mm. After the raw material liquid reaches the boiling point or close to the boiling point after preheating, it is introduced into the tube from the bottom of the heating chamber, and quickly vaporizes after being heated. The generated secondary steam rises at a high speed in the tube, driving the raw material liquid to flow upward along the tube wall in a film-like manner and evaporate and concentrate Finally, the required concentration is reached at the top of the heating chamber, and the finishing liquid and the secondary steam enter the separator from the top of the evaporator to realize the separation of the finishing liquid and the secondary steam. The speed of the secondary steam in the heating tube should not be less than 10m/s, generally 20-50m/s, and can be as high as 100-160m/s or higher under reduced pressure.

Main Feature:

        The rising film evaporator is continuously feeding and discharging materials during the production process. After the evaporation parameters are stable, the material liquid does not circulate in the evaporator. Strictly speaking, it can meet the designed evaporation requirements once the material is fed and the material is discharged. The rising film evaporator should not start feeding too fast, and a certain material level must be maintained in the heating tube, otherwise it will be difficult to form a film. Since the cloth film of the material liquid in the heating tube is formed entirely by the high-speed secondary steam flow and the vacuum, the film is unstable. When entering the separator, the secondary steam is prone to mist entrainment, resulting in incomplete separation and running away. material. The feed pump does not require a forced circulation pump, and only needs to maintain normal feed.

Scope of Application:

The rising film evaporator designed by Jiangsu Heide is suitable for the solution with large evaporation capacity (ie dilute solution), heat sensitivity and easy foaming. It is not suitable for materials with high viscosity, crystal precipitation or easy fouling.