How long a dwell time does ISO Viscosity Grade 220 gear oil need? (220cSt @ 40 deg C)
It is lubricating a critical piece of machinary. The lube oil skid will supply oil at 160 L/min so the dwell time (time in tank to remove air) will make a significant difference to the size of the tank.
Too big a tank will take too long to heat oil on startup, and there are space considerations. It is a gravity return line to tank.

I think that would greatly depend on the exact oil you are using. Some will have more anti foam additives than others.

Timmy,
ASTM 892 is your best way to determine the specific anti-foaming tendencies of your particular lubricant. Get a lab to run the tests and give you time based readings. However these test results will be affected in the application by things such as temperature and contamination etc. There are other lubricants such as hydraulic fluid that have better (typically) anti foaming tendancies than a gear oil. Are you sure the application will generate an air entrainment issue for you?
regards......