Rising Film Evaporator  is widely used in pharmaceutical, food, chemical, biological engineering, environmental protection engineering, waste liquid recovery and other industries. If it is applied in food, it can continuously evaporate and concentrate the thermosensitive materials such as glucose, fructose, fresh milk, tomato juice, soybean milk, xylitol, sorbitol, VC, starch sugar, Chinese medicine extract and so on, so as to improve the product concentration. 

Principle :

The rising film evaporator preheats the feed liquid to the boiling point, adds it from the bottom of the heating chamber and vaporizes strongly in the heating pipe, so that the generated steam drives the feed liquid to rise in a film shape along the pipe wall. The liquid film continues to evaporate in the rising process. The solution only needs to pass through the heating tube once to reach the required concentration. This evaporator is suitable for dilute solutions and heat sensitive materials with low concentration.

Characteristics :

The heating chamber of the rising film evaporator is composed of single or multiple vertical tubes, the length diameter ratio of the heating tube is 100 ~ 150, and the pipe diameter is between 25 ~ 50mm. After the raw liquid reaches or approaches the boiling point after preheating, it is introduced into the pipe from the bottom of the heating chamber. Driven by the high-speed rising secondary steam, it flows in a film shape along the wall edge and evaporates. The required concentration can be reached at the top of the heating chamber, and the finished liquid is discharged from the bottom of the separator. The velocity of secondary steam in the heating pipe shall not be less than 10m / s, generally 20 ~ 50M / s, and can be as high as 100 ~ 160m / s or higher under reduced pressure.

If the liquid under normal temperature is directly introduced into the heating chamber, there must be a part of the heating surface at the bottom of the heating chamber to heat the solution to reach the boiling point before it can vaporize. The solution cannot flow in a film on this part of the wall. In various flow states, the film flow effect is the best, so the solution should be preheated to the boiling point or close to the boiling point before being introduced into the evaporator.