Forced circulation is the most rugged type of evaporator specifically designed to handle fouling liquid and crystallisation during evaporation. As a leading forced circulation evaporator manufacturer & supplier in India, our forced circulation type design ensures liquid circulation in calandria (main evaporator heat exchanger body) at high velocity in the 2 to 4 m/s range based on the feed composition. This type of evaporator needs large recirculation flow rates to maintain high velocities across tubes. Axial flow pumps are normally used due to low head and high flow requirements. 

The axial flow pump also helps maintain crystal size, allowing the crystal to pass through with minimum grinding across the pump. Usually, forced circulation evaporator design uses single pass construction in vertical installation and two pass construction in horizontal construction. More than two pass design is not desirable as forced circulation type evaporators can have pool boiling and cavitation possibilities which can compromise plant life, cleaning cycle duration and life of the mechanical seal.

 How Falling Film Evaporators Work

In the falling film evaporators, the heating media gets circulated through the shell side of the heat exchanger. The process fluid passes through the tube side of the evaporator, and energy gets transferred from the heating media into the product. Then, a portion of the product gets vaporized.

A thin film of liquid on the tube surface ensures a very low liquid circulation requirement and high heat transfer coefficients.

Moreover, the term “falling film” basically refers to the liquid firm that comes down the tubes and is the source of the heat exchanger’s name.

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    General Detail

    • Evaporation inside Surface of Tubes
    • Condensation outside Tubes
    • Usually, Triangular Pitch for High Heat Transfer Coefficient and Low Capex
    • Vertical Installation

    Falling Film Evaporator Design Features

    • TEMA Type BEM or similar Construction
    • Tube wetting rate requirement 1-3 Ltr/mm of Wetted Periphery depending on Viscosity, Surface Tension and density
    • Variety of Distributor Options
    • No Hydrostatic Head required
    • Very high liquid Velocities across tubes due to vapour drag
    • GMP Construction possible

    Advantages of Falling Film Evaporator

    • Low Pressure drop & High Heat Transfer Coefficients
    • Low Recirculation of Feed for Tube wetting or no recirculation
    • Low Footprint Requirement, Low Capex, Low retention time for product
    • Once through Feed pattern possible
    • Can work at very low temperature difference

    Applications of Falling Film Evaporator

    While the applications of falling film evaporators are the concentration of dairy products like skim milk, cream, sugar solutions, urea, phosphoric acid, black liquor, etc, there are many more.

    • Evaporators are best suited to various industrial applications, especially in food processing.
    • Whey and milk proteins are also processed with the help of evaporators.
    • They are used in waste management from plans, including grain mills, distilleries, textile plants, and storage tanks.

    As a falling film evaporator supplier, we will first learn about your intended industrial applications and then offer the falling film evaporator.

    Limitations of Falling Film Evaporator
    • Not suitable for Slurry and Crystalline Solids, high hardness and high viscosity 
    • High CIP/ Hydrojetting Frequency
    • More downtime for fouling liquids

    Download our brochure and questionnaire for hydrocyclone to learn more about our innovative process equipment solutions.

    Why Choose Thermosag As a Falling Film Evaporator Manufacturer?

    While there must be several falling film evaporator manufacturers in India, choosing the one that fits your budget and industrial requirements is vital. We at Thermosag believe in thoroughly understanding your industrial requirements and suggesting the best product to fit your needs. Moreover, our team will constantly keep in touch with you from when you come with a prerequisite to the purchase, making the process seamless. Feel free to reach out in case of any queries and we’ll be happy to help.