About PMC Ouvrie Defoamers

Defoam v AntiFoam

Many industrial processes can create foam. Foam in this context are a collection of bubbles that are created when gasses are trapped within a surface created by a liquid. Both “defoamer” and “antifoam” are sometimes used interchangeably, there is an important difference between the terms.

Anti-foaming agents prevent the formation of foam during an industrial process. Defoamers (or de-foamers) act to reduce or remove foam from the product. Defoamers function by attaching to the lamellas (bubble walls) of the foam and rupturing the bond the lamella needs to stay intact. This serves to both reduce the physical volume of the foam as well as release entrained air.

Foams form at the barrier between a gas, usually air, and the surface of the liquid. Turbulent conditions prompt the surface layer to break up and reform into spheres or bubbles with their own surface. The stronger the surface tension of a liquid is, the more difficult it is to break it up with a defoamer.

Foam can create a wide variety of problems, from preventing a complete fill of a container to creating defects in a surface to causing problems with machinery during manufacturing. Foam can reduce the efficiency of a pump. In paper mills, foams can cause quality issues as paper fibers fail to fully bond. Foams can create conditions that allow for bacterial growth. For these and other reasons controlling foam with defoamers is critical.

Foams can form in most liquids common to industrial processing. Petroleum products such as gasoline, kerosene and oils can form problematic foams. Vegetable-based liquids such as corn, canola, coconut and olive oils can form foam as they are processed for use in food manufacturing or during the manufacturing of foods.

Aqueous industrial processes, such as wastewater treatment or aqueous paint manufacturing can create unwanted foams as well.

Defoamer Types

Defoamers used in industry come in several types and forms. PMC Ouvrie manufactures a variety of non-silicone defoamers. Our defoamers are, like most defoaming agents, a combination of carrier and the actual defoaming agent. Among our non-silicone defoamers include:

Oil Based Defoamers - An oil carrier, such as a mineral oil or a vegetable oil will introduce the defoaming agent into a liquid. Depending on the application, a hydrophobic material such as a silica or a wax is added to improve performance of the defoamer. Oil defoamers are the most effective at breaking up foam in typical applications.

Water Based Defoamers - Mineral and vegetable oils are used as water-based or aqueous defoamers. Typically the defoaming compound is a fatty acid soap, a fatty alcohol or esters.

Powder Based Defoamers - Some foams have to be reduced with a combination of both a defoaming agent and a hydrophobic material such as silica or wax. The hydrophobic material is able to disrupt the lamella of the bubbles and deliver the defoaming agent and disrupting the foam.

Water Based Defoamers - Mineral and vegetable oils are used as water-based or aqueous defoamers. Typically the defoaming compound is a fatty acid soap, a fatty alcohol or esters.

In general, foams are going to form in aqueous and non-aqueous liquids. Both aqueous and non-aqueous foams can be reduced with a defoaming agent.

Aqueous liquids found in food manufacturing, paper and pulp processing and wastewater treatment require a defoamer formulated to work with these fluids. Broadly speaking, water-based fluids require both the defoaming agent and a hydrophobic material such as silica or wax to facilitate the defoaming action. Most often this is in the form of a powder that is added to a liquid in suspension.

Non-aqueous liquids such as those found in mining and drilling, construction or paint manufacturing use liquid defoamers, most often carried by mineral or vegetable oils. These defoamers can be formulated with hydrophobic materials like waxes and silica to increase their effectiveness.