Air compressors have numerous applications in industry and are used in various fields, including automation and assembly, chemical manufacturing, agriculture and construction. All compressors work by converting power from an external source, such as an electric motor or diesel engines, into stored energy which can be released in the form of pressurised air. The pressurised air is then used to power tools and machinery.
Choosing the Right Air Compressor
However compressors vary in their method of operation, air capacity and level of pressure that they can deliver. The right compressor will able to hold enough air and deliver a high enough level of pressure for the task, but performance should be balanced against considerations such as cost and durability. Compressed air is measured in cubic feet per minute (CFM), with a high requirement for CFM needing a larger air capacity and higher horsepower (HP).
Types of Industrial Air Compressor
There are three major types of industrial air compressor based on the method of operation. These are reciprocating compressors, rotary screw compressors and centrifugal compressors.
Reciprocating compressors are positive displacement compressors, where air is reduced in volume to increase its pressure. Reciprocating contain pumps driven by pistons with a cylinder compressing and displacing the air. There are two types, direct drive compressors and belt drive compressors. Belt drive compressors are more durable and able to deliver higher pressures. Reciprocating compressors are available in single stage and multi stage. Multi stage compressors deliver higher pressures and are more efficient, meaning lower electricity consumption and lower costs. Reciprocating compressors are often portable and suitable for trades people involved in construction and similar fields.
Rotary screw air compressors also work by a positive displacement process. They use two helical screws meshed together to force air through and compress it. The method of operation is a smoother process than that of pistons, with less surges and vibration than that sometimes found in reciprocating compressors. They are durable and easy to maintain. Rotary screw air compressors generally have greater capacities than reciprocating compressors and can deliver higher air pressures. Some types have variable speed drives meaning that airflow and pressure can be closely controlled, and where airflow requirements are variable this can result in significant energy savings. Rotary screw air compressors have various applications, finding use in areas such as construction sites, factories and hospitals.
Centrifugal air compressors work by a different mechanism. They use the momentum gained from a rotating disk to transfer and pressurise air. This process is known as dynamic displacement and is a continuous process, resulting in a steady supply of pressurised air. They can deliver extremely high pressures. However the method also requires higher speeds and higher air capacities than other compressors. The capacity and airflow can be controlled by way of inlet guide vanes. Centrifugal compressors have many applications, and are used for machinery such as pneumatic drills and automotive superchargers and turbochargers, as well as for air conditioning and refrigeration. They are also found in gas turbines, gas pipelines, oil refineries, petrochemical plants and chemical plants.