CAGI Compressed Air Specialist Practice Exam Prep & Study Guide

The type of compressor that utilizes rotating impellers to compress air is the centrifugal compressor. This mechanism works based on the principles of fluid dynamics, where the impeller accelerates the air as it moves through the rotating blades, converting velocity into pressure. Centrifugal compressors are particularly effective at handling large volumes of air and can achieve high pressures, making them suitable for applications that require a continuous supply of compressed air.

On the other hand, positive displacement compressors operate by trapping a fixed amount of air and then reducing the volume to increase pressure. Reciprocating compressors utilize pistons to move air in and out of a cylinder, which is a different operating principle from that of centrifugal compressors. Diaphragm compressors use a flexible membrane to compress air, rather than employing rotating elements. Each of these types serves different purposes and applications, but the defining characteristic of the centrifugal compressor is its reliance on rotating impellers for air compression.