Dahmes Introduces VacuCoil Preheater for Spray Drying

US-based equipment manufacturer Dahmes has launched the VacuCoil high-pressure preheater for spray-drying systems. The device is fitted to the feed line immediately before the atomiser, where it heats liquid concentrate before the material enters the dryer.

The system is intended for concentrates whose viscosity limits spray-dryer throughput. Increasing feed temperature can lower viscosity and allow a higher solids load to reach the atomiser, while excessive heat or longer exposure can denature proteins and affect product quality. Dahmes said the unit is suited to dairy proteins and other heat-sensitive protein concentrates.

VacuCoil uses condensing steam maintained under vacuum to provide an even surface temperature, commonly about 160°F. Its position on the high-pressure section of the line means the product remains at the heating temperature for several seconds. Earlier-stage preheaters can expose the concentrate to heat for several minutes. The heating step also lowers the microbial load in the feed.

Dahmes reports an output increase of 7% to 9% in typical applications, with gains above 11% in specific cases. The company said the equipment can be added to an operating feed line, with most installation work taking place while the plant remains in production. It does not require a new building or permitting, and the additional capacity is available once installation has been completed.

The preheater can be retrofitted to spray dryers made by any manufacturer or included in a new system. One VacuCoil unit is operating at a customer site on sodium and calcium caseinate, which Dahmes described as among the most viscous feeds used in dairy processing. The company also identified plant proteins and protein hydrolysates as applications for the same heating method.