Types of Industrial Air Compressors
The two main types of air compressors are reciprocating and rotary screw. Sometimes called piston-driven, a reciprocating air compressor forces the air from the cylinder into a highly pressurized storage tank. As the more cost-effective option of the two, reciprocating compressors are what you see in most homes. They’re also handy for portable use. As the name implies, a rotary screw air compressor relies on two screws, not pistons, to pressurize the air. These models contain a cooling system that increases the unit’s efficiency. They usually cost a lot more than reciprocating units, but if your need is continuous-use, you probably want a rotary screw model.
How to Choose
What do we mean by continuous use? Think of two common applications that require an air compressor: nail gun and spray painter. The nail gun is considered an intermittent tool because it uses short bursts of air. A spray painter, on the other hand, relies on a continuous flow of air. Whenever possible, choose a rotary screw compressor for continuous use applications. Another way to check how well the compressor will work for your job is to look at the duty cycle. This rating tells you how many minutes of each hour you can safely use the compressor. If the unit has a duty cycle of 75 percent, that means you can use it for 45 minutes out of every hour. 60 minutes x .75 = 45 Thanks to the cooling system and fewer moving parts, rotary compressors typically rate 100 percent for the duty cycle.
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Industrial Air Compressor Operating Considerations
In addition to reciprocating vs. rotary screw air comparisons, you need to consider how the unit compresses air and whether it’s oil-lubricated.
- Single-stage fills the tank in a single function.
- Two-stage models compress the air twice for greater air pressure and flow.
- Oil-free systems provide lubrication via the coating on the pistons and rings. They’re ideal for applications where cleanliness is required. For example, you often see them in dentist’s offices. They also weigh less. However, they do have a shorter lifespan than other models.
- Oil-lubricated compressors lubricate moving parts using oil (obviously). These models are typically larger and have a longer lifespan (assuming proper maintenance).
Finally, make sure the compressor you choose can handle all of your needs. For example, if you use the air compressor for multiple tools, you want a model and pump type that matches your maximum psi.
How Much Does an Industrial Air Compressor Cost?
Numerous factors influence the price of an industrial air compressor, including tank size, power source, and horsepower.
- Atlas Copco GX 4 is a single-phase pump, 5 horsepower, 250V, 53-gallon tank, and 16.6 CFM for average price between $4,000 and $5,000.
- Quincy QGS-15 rotary screw compressor with 54.9 CFM, 120-gallon tank, 3-phase, and 100 percent duty cycle costs between $7,000 and $8,000on average.
- The Gardner Denver Reward series offers 7.5 horsepower, 230V, a 120-gallon horizontal tank, and 51.6 CFM for an average price between $11,000 and $12,000
- Kaeser M58U has a 4-cylinder, 49 horsepower Kubota diesel engine with anti-frost control and 210 CFM for an average price between $23,500 and $24,500.
If you need an oil-less model, expect to pay two to three times what you’d spend on an oil-lubricated unit.
Choosing the Right Compressor
Once you know your budget, you want to make sure you get the right air compressor for your needs. Consider the following:
- Cubic feet per minute (CFM) determines the amount of air pressure. If you use more than one tool, check the CFM of your highest-rated tool. Then, multiply that number by 1.5 to determine the CFM level you need for your air compressor. (You may see this referenced as standard cubic feet per minute, or SCFM.)
- Mobility may be a concern, particularly if you need to move the compressor from site to site. Larger models often include self-contained trailers (which also handles the next item, placement). If it’s a heavier air compressor and does not have a trailer, look for units with wheels or handles (or both).
- Placement of your air compressor is important for two reasons: heat and noise. First, heat tends to flow off of your air compressor, since that’s the main way it releases the energy powering it. Second is noise, which can easily top 100 decibels and is the equivalent of a motorcycle engine. Newer machines tend to be quieter, in the 65 decibel range. To handle heat and noise, you want a ventilated space, i.e. not a closet.
- Tank size helps determine how long you can work – and therefore how quickly. If the tank is too small for the tools you use, the tool winds down more quickly and more often. If your compressor powers multiple tools or one pneumatic continuously, you want a larger tank size.