This special blend has a specific gravity of .86 which should allow for rapid separation from water. It is normally rated for up to 8000 hours of operation.
PAO
In general, lubricants made with PAO allow superior separation when compared to motor oils and automatic transmission fluids due to their ability to shed water. The specific gravity of PAO typically ranges between .85 and .89. This fluid is quite popular for use in rotary screw type air compressors. It usually separates quite readily from water, and is normally rated for up to 8000 hours of operation.
DIESTER
This fluid is the choice when operating reciprocating type air compressors. Although, it tends to be the best at taking the high temperatures present in a recip without varnishing, it is more difficult to separate due to these temperatures. The mechanical shear present from the pistons also makes diester more difficult to separate. Depending on the blend, the specific gravity ranges between .92 and .97. Some manufactures of rotary screw air compressors also use this fluid. It tends to separate well when used in screw compressors and is normally rated for up to 8000 hours of operation.
SEMI-SYNTHETIC
This oil is typically a hydrotreated parafin based fluid and is normally used on smaller horsepower rotary screw type air compressors. It generally separates quite well from water. Specific gravity ranges between .84 and .88 and is normally rated between 2000 and 4000 hours of operation.
POLYGLYCOL
This lubricant is the fluid of choice for use in screw compressors manufactured by Ingersoll-Rand and Sullair. By its very nature, glycol is designed to be soluble in water, and so is this fluid. With a specific gravity that usually exceeds .98, it will not separate in a gravimetric type separator. It requires a Posi-Zorb. It is normally rated for up to 8000 hours of operation.
SILICONE
Sullair markets a proprietary fluid called 24KT. This fluid has a specific gravity of .98 and generally will separate well in a gravimetric separator if given enough time. Life expectancy of this fluid is unknown.
MOTOR OIL & AUTOMATIC TRANSMISSION FLUID
These oils must be evaluated on a case-by-case basis. They usually have a heavy additive package that is designed to protect metal from corrosion. These oils mechanically wrap themselves around the water molecules to prevent them from making contact with the metal. This resulting solution is called an emulsion. Although these oils generally have a specific gravity between .83 and .86, they can be very tough to separate due to the additives. Once an emulsion has been formed the solution becomes even more difficult to separate.The Posi-Zorb works very well on these lubricants.
TURBINE OIL
This is a pure unadulterated petroleum product and normally does not incorporate a heavy corrosion inhibitor additive package. Specific gravity usually tranges between .83 and .87. It tends to separate rapidly in water.
POLYOLESTER
This custom blend is designed to be biodegradable. It is supposed to separate readily from water and with a specific gravity of .922, it should separate quite well.