Concentration – Evaporation

With over 70 years of experience and passion, Ing. A. Rossi is one of the worlds leading innovators and manufacturers of Processing and Evaporation systems for Tomato, Fruit, and many other products. Founded by Angelo Rossi in 1951, the company remains a family operation with 3 manufacturing facilities in Northern Italy, and hundreds of installations worldwide.

Ing. A. Rossi offers a range of evaporation technologies, enabling them the flexibility to provide the processor with equipment solutions optimized to the needs of the product, and the business.

Forced Circulation Evaporators

Forced Circulation Multiple Effect Evaporator Systems
Forced Circulation Multiple Effect Evaporator Systems

For many years, Forced Circulation Multiple Effect Evaporators have been the industry standard for Tomato and many other products. They are ideal for use with pulpy products, especially in the later stages of concentration when the product viscosity increases. The technology is quite clever in its concept, and involves the utilization of a number of evaporation stages, also known as “effects” in a series configuration, each at a progressively lower temperature, to remove water and concentrate the product. Each stage, or “effect” consists of 4 main components:

  • Heat Exchanger driven by steam vapor to elevate the product temperature above the boiling point. Usually, only one heat exchanger utilizes live steam from the plant boiler, and subsequent stages are driven by hot vapor from the prior stage. This configuration allows the energy from live steam to be used multiple times in the system, providing theoretical efficiencies of up to 4 pounds of water evaporation per pound of live steam.
  • Evaporation – Separation Vessel where the evaporation actually occurs. These vessels are kept under a controlled amount of vacuum to depress the boiling point such that the heated product boils vigorously, flashing of significant quantities of water vapor, thereby concentrating the product
  • Recirculation Pump, typically very high flow rate, is located at the discharge of the Evaporation Vessel to continuously push product through the Heat Exchanger.
  • Condenser, to create the vacuum needed to drive evaporation in the Separation vessels, and convert all product vapor to liquid condensate for subsequent cooling.

During operation, fresh product is continuously introduced to the first stage, and progressively metered through each of the subsequent stages. Finally, fully concentrated product is continuously discharged to downstream packaging or processing.

Ing. A. Rossi can provide virtually any size Forced Circulation Evaporator to satisfy your processing needs.

THOR Falling Film Evaporator

Falling Film Evaporator
Falling Film Evaporator

Falling Film Evaporators are ideal for clear juices as they offer rapid, high efficiency heating and reduced residence time in the process. This results in less overall thermal damage, better organoleptic characteristics and color retention. Historically, many clear juices, especially citrus products like frozen orange juice concentrate, have been processed with Falling Film systems. The key to the technology involves creation of a thin film of product on the heat exchanger tube surface which, as the name implies, falls downward by gravity. By keeping the layer of product thin, heating occurs very quickly and evaporation starts almost immediately in the tube. Systems can be configured in multiple stages, or effects, for sequential vapor use and energy efficiency. Alternatively, systems are available with Mechanical Vapor Recompression (MVR) for even better energy efficiency and lower temperature operation. More on MVR below or white paper.

THOR Hybrid Flow MVR Pre Concentrator for Tomato

THOR MVR Hybrid Flow Evaporators at Pacific Coast Producers in Woodland CA
THOR MVR Hybrid Flow Evaporators at Pacific Coast Producers in Woodland CA

Until only recently, Tomato Processors relied only on Forced Circulation Evaporators and accepted a 3:1 or 4:1 steam usage efficiency as the best they could achieve. To improve this, some tried Falling Film technology as a pre concentration step to improve energy efficiency, but invariably struggled with excessive downtime for cleaning as the pulpy tomato would quickly plug the heat exchangers. Now, there is something new, something disruptive, and far better, with 20:1 or higher steam efficiency, and 40 days minimum run time guaranteed. It’s the THOR Hybrid Flow MVR System. Click here for more info on the THOR.