Behavior towards air: solubility of air in oil
Hydraulic fluids - Analysis methods

The presence of air in a hydraulic circuit always leads to serious disturbances (cf. article [BM 6 012] , § 8) [29]:

• compressibility of the air-fluid mixture ;

• oil oxidation ;

• temperature rise due to this compression, resulting in accelerated weathering;

• lubrication failure ;

• cavitation.

The circuit must therefore be designed and maintained in such a way as to avoid air ingress wherever possible. As far as the fluid is concerned, it is necessary to give it two different properties:

• anti-foaming properties ;

• deaeration speed.