Engineering for viscous product heat treatment

The Alfa Laval ViscoLine series utilises corrugated tubes to induce turbulence even at low flow velocities. This design is foundational to the efficiency of the unit, as the internal geometry disrupts the boundary layer of the fluid, increasing the overall heat transfer coefficient compared to smooth-tube designs while maintaining a compact footprint. All models are constructed to manage thermal expansion through integrated bellows or expansion joints, which absorb mechanical stress during temperature cycles. The units are designed to operate at up to 190 °C (374 °F), with compliance to PED 2014/68/EU and entitlement to bear the CE mark.

Annular design for non-Newtonian products

For products with extremely high viscosity, the ViscoLine Annular unit employs four concentric tubes. The product medium flows between the second and third concentric tubes in counter-current relation to the service medium, allowing simultaneous heat transfer from both the internal and external service channels. This dual-surface contact provides precise thermal control for sensitive media such as chocolate sauce, tomato concentrate, banana paste, and mayonnaise. Users can fully inspect the product side by removing the tube insert, supporting hygiene requirements in food production. The product side gap ranges from a minimum of 5.8 mm (0.2 inches) to a maximum of 49.2 mm (1.9 inches).

When to choose each ViscoLine model

Selecting the correct configuration depends on viscosity, particle size, and process requirements. The ViscoLine CIP unit is optimised for heating water or CIP solutions such as NaOH and HNO3 using steam or hot water, featuring corrugated 316L product tubes and a 304 service shell. Vertical installation is recommended for this model when used in steam-to-water heating to allow condensate drainage. The Monotube model suits media with large particulates such as grape mash or diced vegetables, as its single tube-in-tube, fully welded construction prevents clogging and eliminates spare parts requirements. The Multitube model is preferred for higher throughput applications involving low-to-medium viscosity products with small fibres and particulates, bundling multiple tubes inside a shared shell. For the most demanding non-Newtonian fluids, the Annular model provides dual-sided heating across up to four concentric tube layers.