1.1 This standard specifies the method to determine foaming characteristics of lubricating oils (especially refer to power fluid and engine oil) at 150 ℃.
1.2 Foaming characteristics of lubricating oils at 93.5℃ are determined according to the method of GB/T 12579.
1.3 This standard is related to some hazardous materials, operation and equipment; however, not all the safety problems related to these are put forward proposals. Therefore, suitable safety and protective measures shall be established and applicability management system shall be provided with before the users use this standard.
2 Normative References
The following standard contains articles which, through reference in this text, constitute provisions of this standard. Unless there are definite additional provisions in the standard, the following normative references shall be current and effective.
GB/T 12579 Determination of Foaming Characteristics of Lubricating Oils
3 Terms
The following terms are adopted for this standard.
3.1
Diffuser
The component is used to diffuse gas into liquid.
Note: though diffusers include metal or nonmetal diffusers, only the metal diffusers made of sintered stainless steel are used for this standard.
3.2
Entrained air (or gas)
The two-phase mixture which is formed in the liquid where the air (or gas) is dispersed, thereinto the majority of volume is filled with liquid.
Note: air (or gas) exists in the form of discontinuous air bubbles with the diameter of 10 μm~1000 μm; these air bubbles are not distributed uniformly. As time goes on, air bubbles rise to the surface, gather to form larger air bubbles and then are broken or form foam.; Air bubbles may also gather on secondary surface in this case, air bubbles rise more quickly.
3.3
Foam
It refers to the air bubbles gathering in liquid or on the surface; in consideration of volume, thereinto air (or gas) is the key component.
3.4
Gas
It has no fixed shape and fixed volume and can be expanded unlimitedly (such as air).
3.5
Lubricant
It is between two surfaces and used to reduce the friction or abrasion between them.
Note: lubricant refers to the lubricating oil including or excluding additives (such as foamer inhibitor) for this test method.
3.6
Zero foam
It refers to that there is no foam at any part of top surface of liquid during foam test.
