Spray Congealers

Spray Congealers are used in spray cooling. Spray cooling (alternatively spray congealing) is defined as a process by which a melt is formed into particles of spherical shape by spraying the melt into a cooling chamber through which ambient or cooled, low temperature air is passing. Rotary (wheel) atomizers and nozzles are used to spray the melt. Spray cooling finds applications in the chemical, food, and pharmaceutical industries. It is a most convenient method of transforming melted feedstock into free-flowing particulates of controlled particle size.

Importance

Products that form melts have a solidification curve. When a spray of melt droplets contacts a cool air environment, the melt cools to a solidification temperature. Congealing then takes place at a constant temperature during release of the product's heat of solidification. When no longer in a fluid state, the droplets further cool to give stable solid particulate forms.

Some products do not have a clearly defined solidification point. The phase change may take place over a range of temperatures or the product may go from a melt phase to solid amorphous form without the release of heat of solidification, since a non-crystalline formation occurs. The droplet may sub-cool below the solidification temperature before suddenly hardening. Data on the physical properties of the melt and behavior during solidification is important to size the cooling chamber, select the atomizer, and determine whether the cooling should be conducted in one or two stages.

Common Products Produced

• Encapsulated materials
• Fats
• Glycerides
• Hydrates
• Inorganic / organic melts
• Quaternary ammonium compound
• Stearic acid/stearates
• Waxes