This is a presentation on rotary compressors which is a part of fluid power engineering.

1. Prepared by :
Kunj Thummar
Sumit Patel
Jasvant Maliwad
Gunjan Vasava

2. • It is a machine which takes air or any
other type of gas at low pressure and
compresses it to a high pressure.

3. CLASSIFICATION

4. • Rotary compressor is a mechanical device which is used
for delivering large quantity of air up to pressure of 10
bar with continuous flow. Different types of rotary
compressors are as follows :

5. • Positive displacement rotary compressors : In these
compressors air/gas is compressed by trapping it in a
reducing passage formed by a set of engaging
surfaces. The gas pull from suction side and push to
delivery side by the help of engaging surfaces.
• Roto dynamic rotary compressors : in these type of
compressors, the compression of vapor/gas is carried
out by a rotating elements imparting velocity to the
flowing gas and developed desired pressure and
compression is achieved by dynamic action of rotor.

6. CONSTRUCTION
• It contains generally two
lobes.
• It contains a casing inside
which there are two
shafts fitted with two
lobe rotors.
• One rotor is driven by
motor and another by
gears.

7. WORKING
• Air is drawn through inlet pipe
due to rotation of rotors.
• The volume of air is trapped
between rotor and casing for a
short time interval.
• Due to rotation of lobes
trapped air is carried out to the
discharge side.
• Continued rotation of rotors,
opens the trapped space to the
discharge part.
• The air is pushed to the
receiver due to the continued
rotation of rotor.

8. CONSTRUCTION
• It contains rotor drum
mounted eccentrically in a
cylindrical casing.
• Vanes remain in contact
with wall due to centrifugal
action.
• Vanes can slide in and out
of the slots.

9. WORKING
• The rotation of rotor caused space
between vanes, the rotor and casing.
• The space is connected to the suction
pipe.
• In this space the air enters and fills the
whole space.
• With rotation the air gets compressed
due to reduction of space towards
delivery.
• The fluid volume is now reduced and
communicates with the delivery pipe.
• Due to pressure difference in
compressed air and the receiver
pressure back flow of air takes place,
which causes further rise in pressure of
internally compressed air.
• This air is now delivered to the receiver.

10. • CONSTRUCTION
• It contains two mating
helically grooved rotors.
• Rotors are suitably housed
in a cylinder.
• Cylinder are equipped with
appropriate suction and
discharge ports.
• Rotors are driven by
synchronized gears.

11. WORKING
• Gas enters from the suction
side and progressively gets
compressed as it moves
through the narrowing
passage formed by lobes.
• Compression is obtained by
following stages :
1. Suction
2. Transportation
3. Compression
4. Discharge

12. CONSTRUCTION
• It contains two matching scrolls.
• One of them is fixed and other free
to orbit.
• These scrolls form series of space
packets between two mounting
spirals.
• These spaces are filled by gases
while in working condition.
• Suction take space at outer edge
and delivery for center fixed port.

13. WORKING
• When shaft rotates the orbiting
scroll open the suction port.
• Gas enters in the space created.
• Further rotation of shaft
reduces the gas pocket area
hence increasing the pressure.
At the end of third revolution
thee gas is delivered out for
delivery port.