Types of Air Compressors
Let’s take a look at the common types of air compressors.
Table of Contents
Overview
There are a many of types of air compressors to choose from. When making the decision for a new compressor, considering your needs and usage will save you time, money and headaches. First thing to decide is usually the type of compressor you want.
Each type of air compressor has it’s own advantages and disadvantages, and advantages in one application might be a disadvantage in another application.
We get asked “what compressor is the best?” and the answer is, without more information, we just can’t say. It really depends on what the application is.
We will discuss the most common types of air compressors below without going into further details about subtypes of those compressors (see linked pages for greater detail). The pros and cons of each type are highlighted along with some typical use cases. Hopefully this will give some direction to what type of compressor you should choose.
Positive Displacement.
These are going to be your common use types of compressors and what will be covered here.
Dynamic.
Centrifugal and axial compressors are considered dynamic and are not something the average user will run into.
Reciprocating Piston Compressors
Pros:
- Relatively inexpensive (lower purchase cost)
- Easier maintenance and less expensive
- Use for high pressure applications
- More portability
Cons:
- Only use for intermittent air
- High noise levels
- Lower efficiency
- Higher cost of air
The working principal is a piston moves inside (reciprocates) of a cylinder to compress the air. Piston compressors are available in many different configurations but most commonly are two cylinders. Available from less than a horsepower up to 30 horsepower.
Reciprocating piston compressors are very common for general purpose applications like workshops, auto or portable. They work well with hand tools, cleaning dust etc. They are not the compressor to be used where constant flow is a requirement.
Rotary Screw Compressors
Pros:
- Low noise level.
- Continuous uninterrupted air
- High efficiency
- Long service life
- High reliability
Cons:
- Higher purchase cost
- Higher maintenance cost
- Not ideal for intermittent loads
Rotary screw compressors use two rotors (helical screws) that compress the air. Input air is trapped between the rotors which have very minimal clearance between and is compressed down and pushed out through the pressure side.
Rotary screw compressor are (like piston) one of the most common types of air compressors and the majority have fall in the three horsepower up to 500 horsepower range.
Scroll Compressors
Pros:
- Very quiet
- Less moving parts
- Low maintenance
- Oil free
Cons:
- High purchase cost
- Lower air capacity
- Higher temp air
- High cost if a failure happens
Scroll compressors use two spirals, one being stationary and the other moving in small concentric circles, trapped air then compresses and moves toward the center of the spiral.
Scroll compressors are not as common as the above mentioned and are seen more where oil free air is necessary.
Rotary Vane Compressors
Pros:
- Continuous air
- Less moving parts
- Easy maintenance
- Long life
Cons:
- Not as efficient as rotary screw
- Lower air capacity
- Limited pressure
Rotary vane compressors use an elliptical slotted rotor housed in a cylinder. Each lot has a vane along the length. The vanes are forced outward by centrifugal force, gathering air from the input and forcing it out the other side.
Vane compressors are generally seen in smaller applications and/or where floor space is an issue.
What type of compressor should you buy?
Now that we have reviewed the types of air compressors, ask yourself the following. What are your needs going to be? Do you need a lot of air or just have the occasional need? What are the requirements for the equipment/tools you use (manufacturers will state CFM requirements)?
If you are just using a nail gun for example the choice becomes pretty easy (buy a piston compressor). But if you are manufacturing consumable items, you would need an option that is oil free then you may want to look beyond a piston compressor as while there are oil free options for a larger amount of air it would not be the most practical option.
Do you need to have a continuous flow of air? Or a lot of air? A rotary screw compressor would probably be your best choice. Maybe you are limited to space requirements or need to fall below a decibel threshold? These will all come into play in choosing the right compressor for your application.
If you are just not sure, we would be happy to assist.
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