Foam aerator machines

Food industry foams are often prepared using aerator machines. In batch aerators, the gas is usually whipped into the hquid. An example is the Oakes Mixer, in which a slurry is continuously stirred and aerated under pressure between a series of blades. In continuous aerators, a mixing head whips the gas into the hquid under pressure. In this case, the foam expands as it leaves the machine. 

The entrainment of air in lubricating oil can be brought about by operating conditions (for example, churning) and by bad design such as a return pipe that is not submerged. The air bubbles naturally rise to the surface, and if they do not burst quickly, a blanket of foam will form on the oil surface. Further air escape in thus prevented and the oil becomes aerated. Oil in this condition can have an adverse affect on the system that, in extreme cases, could lead to machine failure. The function of an anti-foam additive is to assist in the burst of air bubbles when they reach the surface of the oil. 

A machine used for preparing foams in the food industry. A slurry is continuously stirred and aerated under pressure between a series of blades. See also Aerator. 

Uses Effluent system defoamer for foam control in textile, paper, and municipal effluent systems in aeration ponds, flumes, and at river outfall paper machine defoamer esp. for recycled fiber furnish foam control agent for coatings based on starch, casein, and waxes Features General purpose exc. dispersing props. 

Both domestic batch-scale and industrial continuous dishwashing machines are employed. A schematic diagram of the former is depicted in Figure 8.15. The device includes racks to support dishes, which are subject to aqueous sprays directed from below. The impact of the spray onto already wet surfaces results in aeration by a process that may, in some measure, resemble that occurring during a continuous Ross-Miles foam test (see Section 2.2.3). The presence of surface-active material therefore leads to foam formation. 

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