Falling film evaporator tubes are specifically designed for falling film evaporation systems. In a falling film evaporator, liquid is evenly distributed through a top distribution device onto the inner or outer surface of the tube bundle, forming a thin film that flows downward during heating and evaporation.

Shell's falling film evaporator tubes feature an optimized surface structure that ensures uniform liquid film coverage, prevents dry spots and scaling, while maximizing heat transfer area and fluid disturbance. These tubes are widely used in central air conditioning falling film chillers, seawater desalination plants, food concentration equipment, and chemical evaporation systems. A variety of materials are available to suit different working fluids and operating conditions.

Heat exchange tubes for falling film evaporators

Core Advantages

Uniform Film Distribution Design

The specially designed surface geometry promotes uniform liquid film spreading across the tube surface, preventing dry spots, localized overheating, and scaling.

High Film-Side Heat Transfer

The enhanced surface structure increases turbulence and effective heat transfer area on the film side, providing superior overall heat transfer coefficients compared to conventional tubes.

Anti-Fouling Performance

The optimized surface finish reduces scale adhesion and fouling buildup, extending operating cycles between cleaning and lowering maintenance costs.

Multi-Material Availability

Available in copper, copper-nickel, stainless steel (304/316L), and titanium to meet different fluid chemistries, temperature ranges, and corrosion resistance requirements.

Technical Parameters

Outer Diameter (mm)	Bottom Wall (mm)	Tooth Height (mm)	Number of Teeth	Helix Angle (°)	Weight (g/m)	Heat Transfer Area (m²/m)	Material
7.00	0.25-0.32	0.12-0.18	45-55	15-25	42-50	0.021-0.024	TP2, T2
9.52	0.30-0.40	0.14-0.20	50-65	18-28	52-62	0.025-0.028	TP2, T2
7.94	0.27–0.35	0.12–0.18	45-60	18>28	63–75	0.028–0.032	TP2, T2

Typical Applications

Central HVAC Falling Film Cooler

Falling film evaporator for large commercial and industrial centrifugal chiller systems in office buildings, hotels, and hospitals.

Multi-Effect Distillation Seawater Desalination

Heat transfer tubes used in MED (Multi-Effect Distillation) seawater desalination plants to produce fresh water from seawater.

Food Concentration Equipment

Evaporator tubes used for concentrating fruit juice, dairy products, syrup, and other food liquids in the food processing industry.

Chemical Evaporation and Crystallization

Falling film evaporators used in the chemical industry for chemical solutions, brine concentration, and crystallization processes.

Frequently Asked Questions

Q: What is the difference between a falling film evaporator tube and a flooded evaporator tube?

In a flooded evaporator, the tubes are completely submerged in liquid refrigerant or coolant, and boiling occurs directly on the tube surface. In a falling film evaporator, the liquid is distributed as a thin film that flows along the tube surface, and evaporation occurs from the film. This key difference drives distinct tube surface requirements: flooded tubes require enhanced boiling surfaces (porous, fins) to promote nucleate boiling, while falling film tubes require surfaces that promote uniform film spreading and maintain film stability. Falling film designs also typically require less refrigerant charge and provide better temperature approaches.

Q: How do you ensure uniform liquid film distribution across the entire tube bundle?

Uniform film distribution is achieved through a combination of proper liquid distribution system design and tube surface optimization. Our tubes feature surface structures that promote rapid and uniform liquid spreading around the tube circumference. At the system level, proper inlet distributor design, tube spacing selection, and liquid loading per tube are critical. Kenergy provides tube products and distribution design recommendations to ensure optimal wetting. We also offer customized surface patterns to enhance film formation characteristics in challenging applications.

Q: How do you clean fouled falling film tubes?

The cleaning method depends on the type of fouling. For soft and organic fouling, chemical cleaning with appropriate detergents or mild acids is effective. For hard mineral scale, controlled acid cleaning with inhibitors is recommended. For tubes with smooth or low-fin surfaces, mechanical cleaning with soft brushes or high-pressure water jets can also be used. Our anti-fouling surface treatments significantly reduce cleaning frequency. We recommend establishing a regular inspection and cleaning schedule based on your specific water chemistry and operating conditions.

Q: Can falling film tubes be used for seawater desalination? What materials do you recommend?

Yes, falling film evaporator tubes are widely used in multi-effect distillation (MED) and mechanical vapor compression (MVC) seawater desalination plants. For seawater desalination, we recommend CuNi10Fe1Mn (90/10 copper-nickel) due to its excellent corrosion resistance in seawater environments. For higher temperatures or more aggressive conditions, 316L stainless steel or titanium (Grade 2) are also available. The tube surface structure can be optimized to enhance wetting and heat transfer for seawater. Kenergy has extensive experience supplying tubes for seawater desalination projects worldwide.

Heat exchange tubes for falling film evaporators