Knowledge

All lubricating oils contain a certain amount of air. Foaming in lubricating oil refers to forming small bubble clusters, where each bubble possesses equal strength in all directions. The potential risks associated with dissolved air are generally linked to the accelerated depletion of additives and the oxidation of the lubricating oil.

When the oil accumulates more air, it is called entrained air. In this state, suspended microscopic air bubbles cloud the oil's appearance. Entrained air can also adversely affect both the machine and the oil. Issues such as oil comprehensibility, and film strength failure can harm equipment components and impact performance. Hydraulic comprehensibility, corrosion, and the loss of system controls are often connected to the presence of free air.

Foam represents the final stage of air contamination. It can significantly damage machine components, as it may enter the pump's suction line, resulting in oil starvation, comprehensibility problems, and vapor lock. The presence of foam serves as an indicator that an undesirable change has occurred within the oil reservoir. Factors like oxidation, polar contaminants, water contamination, and solvents can reduce surface tension, leading to poor air release and foam formation. The existence of foam may also result in operational issues and expedited lubricant oxidation.

Foaming in oil has highly undesirable consequences, including increased oxidation due to intensive mixing with air, damage from cavitation, and inadequate oil transport in the lubrication circulation system, resulting in insufficient lubrication. Inadequate lubrication means that the metal surface with an air bubble lacks lubricant, leading to metal-metal interaction, increased friction, and damage to the parts.