Air Compressors 1

OVERVIEWThe purpose of this unit is to introduce trainees to various types of air compressors, describe the functions of compressor components, and explain the general requirements of a compressed air system. The function of a compressed air control system is also discussed.At the conclusion of this unit, trainees should have a basic understanding of the operating principles of both positive displacement compressors and dynamic compressors. They should be able to identify seven different kinds of compressors and explain the functions of their basic controls and accessories. OBJECTIVESThe Compression Process-------------------------------------- * List several common industrial uses for compressed air. * Name the two general categories of air compressors. * Explain how the principles of operation differ between the two general categories of air compressors. * Define the two factors that determine a compressors capacity. List the units typically used to measure each factor. * List three methods used for cooling compressors and compressed air. * List three reasons why moisture must be removed from compressed air. Reciprocating Compressors--------------------------------------- * Explain the principle of operation of a reciprocating compressor. * List the four ways that reciprocating compressors can be categorized. * List the accessories with which reciprocating compressors are commonly equipped. Air Compressors------------------------ * Name the basic parts of a rotary screw compressor and explain how they function. * List the differences between dry and wet rotary screw compressors. * Name the basic parts of a sliding vane compressor and explain how they function. * List the differences between oil-lubricated and oil-flooded sliding vane compressors. Liquid Ring Compressors and Rotary Blowers * Name the essential parts of a liquid ring compressor and describe how they function. * Describe the function of the liquid in a liquid ring compressor. * Name the essential parts of a rotary blower and describe how they function. Dynamic Compressors * Explain how a dynamic compressors principle of operation differs from that of a positive displacement compressor. * Name the essential parts of a centrifugal compressor and describe how they function. * Name the essential parts of an axial compressor and describe how they function. Control Systems * Describe how on/off cycling and variable speed controls are used in compressed air systems. * Describe the function of an inlet valve unloader. * Describe the function of clearance pockets. * Describe the function of air-controlled inlet valves. * Describe the function of flow controllers and blowout valves. * Describe the function of inlet air throttles. SUBJECTS * The Compression Process * Types of Compressors * Capacity * Cooling and Moisture Separation * Reciprocating Compressors * Principles of Operation * Categories * Accessories * Rotary Screw and Sliding Vane Compressors * Rotary Screw Compressors * Sliding Vane Compressors * Liquid Ring Compressors and Rotary Blowers * Liquid Ring Compressors * Rotary Blowers * Dynamic Compressors * Centrifugal Compressors * Axial Compressors * Control Systems * Universal Compressor Controls * Positive Displacement Controls * Dynamic Compressor Controls * Constant pressure controls * Anti-surge controls * Motor load "choke" controls