Rotary screw air compressors work by having two screws - a male and female rotor - rotate together to suck in and compress air. As the screws mesh and their lobes engage, they reduce the volume of the air pockets to continuously compress the air. There are different types of rotary screw compressors depending on their cooling method, stages, and drive type. They are more efficient than reciprocating compressors but also more expensive.

2.  in rotary screw air compressors, the most
important part is the screw unit. For this reason
they are called as rotary screw.
 When compressor start running, firstly, it raises
the compressor’s inside pressure approximately
1-2 bar.

4.  It consist of two screws - one with convex
and the other with concave contour
mostly called male and female rotor
respectively.
 These two screws gets rotating by means
of gear trips there by sucking the air
through an inlet port in chamber and then
compressing the same.

5.  Thus compression begins and air is
discharged at the end of other side.
 There is no contact between male and
female rotors and casing. Hence no
lubrication require but oil may injected
for the purpose of cooling.

7.  The helix of the male and female rotor screw
is designed to permit complete charging of the
inter lobe space before the re-mesh.
 On completion of the filling operation the inlet
end of male and female lobes begins to re-
engage thus reduces the volume of air
continuously.

9.  There are many different types of rotary
screw air compressors based on :-
1. Stages
2. cooling method
3. drive type.
 COOLING METHODS :-
1. Oil-free compressors
2. Oil-Injected Compressors

10.  Advantages :-
 Screw air compressors are designed as quiet by
the manufacturers.
 More efficient than reciprocating compressors.
 Screw air compressors can reach high capacities
that piston compressors cannot.
 These compressors are the high technology
products.
 If services done completely, they are long lived.

11.  Disadvantages :-
 Screw air compressors are more expensive than
reciprocating air compressors.

12.  Did you know?
 Rotary screw technology is the same technology
utilized by superchargers in high-performance
engines !