Methods and devices for foam breaking

Foam can be controlled by chemical, thermal and mechanical means. Chemical defoaming agents (generally extremely surface active substances of limited solubility, e.g. silicones) are best, if they do not impair the quality of the product. 

Thermal foam breaking (by direct injection of steam into the foam space or by indirect heating of the walls) aims at bursting the inflated gas bubbles, while simultaneously lowering the viscosity of the liquid lamellae, ft has proved to be ineffective, frequently resulting in (thermal) damage to the product and incrustation of the heating surface. 

Mechanical foam breaking, the most frequently used method, is essentially based on subjection the foam lamelae to shear stress. In addition, the pressure changes 

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