Frequently Asked Questions about Air Compressors and Blowers

An air compressor is a device that pressurizes and then stores air, generally for the purpose of supplying it to another device. A blower uses a similar process to propel gases or materials with discharged air. You can use both devices for a variety of different industrial applications.

What are the different types of compressors?

Most devices generally fall into two different categories. A positive displacement machine increases the pressure of air by reducing its volume through a compression process. A dynamic compression machine transfers energy from a rotating impeller directly to the air. Blowers also use positive displacement and dynamic compression technologies to accomplish a similar task. Apart from this basic distinction, there are many other ways to categorize a device, including its drive method, its cooling method, and the number of cycles it performs. Here are the most common types of compression methods:

  • Reciprocating - This is a positive displacement machine that uses pistons and a crankshaft to compress gases at high pressure. The process can be divided further into single-stage and two-stage machines, with more stages required at higher pressures.
  • Rotary screw - This is another positive displacement machine. It consists of two rotors that guide air directly into the chamber for compression.
  • Rotary vane - This is similar in concept to the rotary screw device, except it uses a slotted rotor with a varied blade placement.
  • Centrifugal systems - This dynamic compression machine rotates air at high speeds to pressurize it.
How much pressure can a compressor or blower deliver?

You can divide each machine into three different categories based on its pressure level: low-pressure, medium-pressure, and high-pressure. The low-pressure compressors have a discharge pressure of no more than 150 psi. The medium-charge compressors range between 150 psi and 1,000 psi. The high-pressure compressors exceed a discharge pressure of 1,000 psi.

Do oil-free compressors or blowers exist?

Yes, but it depends on the device. Some devices use a coating system instead of oil for lubrication in the compression chamber but may still use oil in other parts of the device for lubrication or cooling. Check the technical details of the device to learn how exactly the device is using oil. New and used oil-free devices have the benefit of better air quality and overall less maintenance, although oiled devices have their benefits as well in terms of noise levels and life span.