Air Compressor

Compressor makes air volume smaller. Oil lubricates it.

Isn't this stuff in your textbook?

This animation may help.

As the rotors unmesh, atmospheric air flows into the space between the rotors and the shell. At the diagonally opposite end, the rotors mesh again and compress the air into the decreasing space beween the rotors and shell. The reduced volume then opens to the discharge port. In addition to lubrication, the oil seals the tiny gaps between the rotors and shell, and also cools the exiting air stream.

Some manufacturers have hand-sized transparent plastic models that make this process even easier to see.

search "roots blowers".

Hi,

Rotary screw compressor is a where compress air to 7-13bar/psi

Ambient air is 1 bar sucks to compressor and air end(piston,screw,centrifugal) in your case screw will pressure the air to certain bar.

Screw have two (male and female) where male is bigger turn by an motor will turn the female. the air will go thru the screw

The oil as coolent for air and the air end, when pressure air is vey hot.

compressing gas does make heat of coarse, but it's my understanding that the rotors have enough clearance to prevent friction and wear. the incoming gas cools the rotors. only the side bearing are lubricated. i'm unsure of how the oil seals are designed, but i'm sure the bearings are under oil pressure.

The principle of operation must be clear by the other explanations. Oil injection in the screw compressors form lubricating layer as well as seal between the two screw's matting line of contact and the between screw tips and shell of the compressors. This oil injection is in addition to the oil going to bearings and seal etc.