Compressor types: different ways to compress air

There are a lot of types of compressors to choose from. Choosing the right type of air compressor for your needs is very important, it will save you a lot of trouble and money in the long run.

You will learn on this page the advantages and disadvantages of the different kinds of compressors.

Which compressor type is right for you?

Read the information we have compiled below and if you need any further help, click here to speak to the team

 

You will find here a shortlist of the most popular types of compressors and I will discuss the pros and cons of each one, including some typical uses.

After reading this page, you should have a fairly good idea of what kind of compressor is best for you.

Rotary screw compressor (oil-injected or oil-free)

Another popular compressor type is the rotary screw compressor.

There are two basic types of rotary screw compressors: oil-injected and oil-free.

The oil-injected type is most common because it has a much lower price tag than the oil-free one (which you should only use if your application requires 100% oil-free air).

 

It uses two rotors (helical screws) to compress the air. The rotors have a very special shape and turn in opposite directions with very little clearance between them.

Air sucked in at one end gets trapped between the rotors, and get pushed to the other side of the rotors (the pressure-side).

Pros:

  • Low noise level. You can just put in in your workshop without wearing ear-protection.
  • These are the work-horses of the compressors and can supply a large amount of compressed air.
  • Good energy-efficiency compared to piston-type compressors
  • Relatively low end temperature of compressed air
  • Possible to use energy recovery

Cons:

  • Purchase price is much higher than piston-type compressors
  • More complex design, good maintenance very important.
  • Minimal air use (per day/week) is required to prevent water condensate forming (will create a lot
    of problems with rust!)

 

Scroll Compressors



I like scroll compressors… they are ‘elegant’.. They run smoothly, with almost no noise, no vibrations and use a clever design principle to compress the air. They are however one of the less seen compressor types.

How do they work? They compress the air using two spiral elements.

One is stationary (it doesn’t move), and the other one moves in small eccentric circles inside the other spiral.

Air gets trapped and because of the way the spirals move, gets transported in small air-pockets to the center of the spiral. It takes about 2.5 turn for the air to reach the compressed air output pipe in the center.

I haven’t seen too many scroll compressors ‘in the wild’ (as compared to other compressor types).

Normally they are used in places where a small amount of oil-free and clean compressed air is needed (for example drinking water-treatment facilities, specialized factories or laboratories, etc). T

hey don’t product a high air flow. If you need a lot of oil-free compressed air, go for an oil-free rotary screw compressor.

Pros:

  • Very quiet. Really very quiet!
  • Compact. A scroll compressor is very small.
  • Simple design, not so many parts
  • Low maintenance (hardly any)
  • Oil-free design

Cons:

  • Low capacity (flow, liters/minute or cfpm).
  • Relatively expensive
  • When the scroll-element fails, there’s a very big chance you just have to buy a whole new element.
  • The compressed air gets very hot! Much hotter than compared to other types of compressors