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ASTM D892 Stones

Measuring Foaming Tendency in Lubricants


The importance of accurately and reliably determine the foaming tendency and foaming stability of lubricant oils has been a theme of discussion for many years. Halt foam is critical for the industry in general to reduce operational costs and increase production. Standardized methods such as ASTM D892, D6058 and IP 146 control tightly flow of gas (typically air) is dispersed into a measured volume of the test liquid at pre-determined conditions of time, air flows and temperatures.

Ayalytical Instruments through its VISAYA product line manufacturers and distributes a series of foam analyzers for the characterization and quality control of fresh and in-service lubricant formulations including a stone calibration unit, the StoneDDI, to provide for unbiased and reliable measurements of pore size distribution and flow rates. and a variety of diffusers of plastic, ceramic and metallic diffusers of different shapes and dimensions.

Certified Norton Spherical gas diffuser stones meet certification requirements for the method specified above. Based on the geometrical shape alone, spherical stone diffusers produce larger bubbles, that tend to coalesce much easier forming larger bubbles causing the foam to break more easily, thus giving slightly better results. Permeability and porosity of diffusers change overtime it is therefore recommended to test them periodically preferably after each use.

Mott certified metal diffuser meets certification requirements for foam methods listed above. There are arguments that metal gas diffusers are much more uniform, easier to clean, and holds it specification for a much longer time than the stone diffuser. Diffusers permeability and porosity change overtime so it is recommended to test them periodically preferably after each use. 

Whether it is for ASTM D0892, ASTM D6058 or IP 146 Ayalytical is in the position to offer you the diffusers to quality control lubricants and monitor the effect and optimal concentration of antifoaming agents.


We offer the following items that cover this method:

Cylindrical Gas Diffuser

Certified Norton Spherical Gas Diffuser