Air Compressors Guide
Compressed air is one of the most versatile and useful forms of energy available. As a result, an air compressor is one of the most effective and cost efficient pieces of equipment one can own. Air compressors can help in completing constructions, maintenance, automotive repair, power nail guns and spray guns faster, than with traditional tools. An air compressor functions by altering air according to the given application. Compressors are equally used in petrochemical and hydraulic sector of industries.
The three general types of compressors are Reciprocating air compressors, Rotary air compressors and Centrifugal air compressors. Among these types of compressors, there are further subcategories to consider such as, Portable and Stationary units. Portable units are used for smaller processes like framing and roofing. They are more efficient units whereas stationary units provide compressed air through fixed pipes which will be attached to the machine. Manufacturers design these units as either lubricated or oil-free. A lubricated unit normally oils the cylinder and other bearings during the process whereas oil-free units work without external lubrication. Oil-free units generally run hotter than oiled compressors.
Compressors are also found as two-stage or single-stage apparatuses. Two stage compressors are generally used for heavy duty applications and generate higher levels of compression. Single-stage compressors generate lower levels of compression and produce more heat compared to a two-stage compressor. Horsepower is also an important factor in determining the type of compressor needed for an application. Operating horsepower specifies the amount of power the motor provides during the operation. Now examining the major types of air compressors,
Reciprocating Compressors/ Piston Compressors:
The reciprocating compressor compresses air with the use of one or more cylinders or pistons. The pistons move up and down (reciprocating) inside the cylinders to compress the air. They are classified as positive displacement machines. These compressors are of low capacity and are designed for intermittent use. Reciprocating compressors are relatively small compressors. They go up to about 10 Horse Power, making them best suited at workshops, garages, constructions and other small scale work areas. These compressors can be either air or oil cooled as they generate large amounts of heat.
The rotary compressor compresses air by two rotors that turn in opposite direction inside the compressor’s housing. Air gets trapped between the rotors and gets compressed. When the rotors start turning, air will get sucked in on one side and later gets trapped between the rotors. Since the rotors are continuously turning, the air gets pushed to the other end of the rotors and new fresh air gets sucked in. Since this is a continuous process, it doesn’t create a lot of noise. The Horsepower of these compressors range from 200 to 300 and sometimes even more as per the application demands.
Centrifugal Compressors (Dynamic Air Compressors):
Centrifugal compressors are majorly meant for heavy duty processes as their horsepower ranges from 100 to 1000, even though some versions exceed this range according to the application requirement. While the reciprocating and rotary compressor models function by compressing air from one volume to another, centrifugal units increase the air’s velocity after raising the pressure. This occurs through a rotor that is equipped with blades. This process itself involves air or gas being forced into an exterior chamber under a higher pressure. Unlike the other compressors, Centrifugal compressors have a higher installation charge and other specialized bearings to be installed. Since these models do not have pressure pulsations, they run quieter and smoother than the reciprocating and rotary compressors.
Since there are many types and models of air compressors, it’s easy to get confused on which one to buy. But one must also be caution on the regard of choosing the right compressor as per the demands of the application. Whether the model must be a continuously running one or a start and stop one, since compressors are manufactured according to varying capacities and horsepower. Overheating and decrease in the lifespan of the machines are common when there is ignorance on the grounds of usage. Large units do not necessarily require overhauls but medium size compressors require a maintenance check in every 3 to 5 years in operation.