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In previous article (Part-A) Positive Displacement Type Air Compressor is described.Now you can increase knowledge about Dynamic Type Air Compressor.
02)Dynamic Type Air Compressor.
The Dynamic Type Air Compressors mechanically impart velocity to the air.This action is produced by the Impellers rotating at a high speed,in enclosed casing.The air is forced into a progressively reduced volume.The volumetric flow will vary inversely with the differential pressure across the compressor.This type of compressor is further classified as (a) Centrifugal Air Compressor (b) Axial Flow Air Compressor (c) Roots Blower Compressor.
(a) Centrifugal Air Compressor.
In a Centrifugal Air Compressor an Impeller is mounted on a shaft and positioned within housing,consisting of an inlet duct,a volute and a Diffuser.The velocity to the air can be impart by the high speed rotation of Impeller.The Diffuser surrounds the Impeller and act to convert the Kinetic energy of air into potential energy at a higher pressure level.
(b) Axial Flow Air Compressor.
The Axial Flow Type Air Compressor is essentially a large capacity,high speed machine withy characteristics quite different from the centrifugal air compressor.Each stage consist of two row of blades,one row rotating & the next row of blade is stationery.The rotor blades impart velocity and pressure
to the air as the motor turns,the velocity being converted to pressure in stationery blades.
(c) Roots Blower Compressor.
This type is generally called as blower.The discharge air pressure obtained from this type of machine is very low.The Discharge Pressure of 1 bar can be obtained in Single Stage and pressure of 2.2 bar is obtained from Double Stage.The discharge pressure achieved by two rotors which have separate parallel axis and rotate in opposite directions.This is the example of Positive Displacement Compressor in Rotary Type Air Compressor.
Prasanna
http://www.pnengineering.blogspot.com/
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