Air tools have become a staple on many jobsites due to the simplicity and advantages they provide. In fact, it’s estimated that nearly every industry now relies on compressed air tooling to some degree. Among their greatest benefits are that they offer freedom from electricity and don’t require their own motor – especially useful in rural areas or temporary locations like fairgrounds or music festivals. But for these tools to perform in locations that range from urban to rural, they do require the support of an adequate air compressor.
Air compressors power everything from large industrial production machinery to individual ratchet and impact wrenches, paint sprayers, and finish nailers. This broad application is where you often find a couple more major advantages of an air system: versatility and power. Regardless of the scope or location of your project, an air compressor accommodates the full range of compatible tools – switched as quickly and easily as changing a drill bit. Plus, when compared to standard tooling, air powered models often provide greater torque and higher RPMs.
Three types
Air compressors are available in three basic types:
- Reciprocating – Positive displacement compressors that provide increased air pressure by limiting the volume of air. Available in single-stage and two-stage, they’re typically capable of outputs ranging from 1 to 15 hp.
- Rotary screw – Positive displacement compressors that are considered simple to operate and maintain. Favored for their ability to provide continuous duty, their design provides cooling within the compressor’s interior, saving the individual parts from extreme operating temperatures and enabling them to deliver outputs that range from 7.5 to 100 hp and up.
- Centrifugal – Compressors that do not rely on positive displacement and are most effective when running at their full capacity, making them ideal for operating environments in which demand is continuous and output needs start around 100 hp.
In general, air compressors are highly durable tools. For example, it’s estimated that a rotary compressor will last for 40,000 to 60,000 hours – the equivalent of full-time operation for 20 to 30 years. With regular maintenance, reciprocating compressors have a life expectancy of 10 to 15 years. Each of the three types also has a number of advantages and disadvantages we’ll cover in more detail below.
Importance of a professional dealer
You’ll quickly discover that air compressor dealers often specialize in a particular brand. The reason is manufacturers typically require exclusivity among their networks. While this entails a little more comparison shopping on your part, it ends up being a plus in the long-run. Specialization enables the dealers to become highly familiar with each of the models they’re selling, the specific applications they’ve been designed for, and the type of service required to keep them up and running.
This expertise allows them to consult on the exact type of machinery best suited to your intended application(s) and also offer value-based service packages at a fixed cost that can help you maintain the investment well into the future. In fact, by some estimates, maintenance and repair can account for as much as 20% of the total investment on a light-duty or industrial air compressor.
Trends
Your specific application and the horsepower required to achieve it effectively will largely determine the air compressor you purchase. But there are a number of trends that may also factor into your purchase decision. The incorporation of one or more of the following has the potential to significantly increase the productivity and cost-effectiveness of your process.
Which of the following could apply to you?
Variable speed drive
This development uses variable speed technology and a special drive to control the speed of the unit, saving substantial energy – up to 35% less with some models – when compared to a fixed speed air compressor. With this vast potential for savings, some dealers cite variable speed drives as “superior to all other control technologies” on the market today.
In short, a variable speed drive automatically pairs its output to the user’s demand for air. The continuous, real-time nature of this development is what provides its peerless energy efficiency, reducing demands for power and fuel while also cutting emissions. Further cost and energy savings are found in its ability to provide unlimited motor starts, progressing from zero to full load without spikes in electric current or generating surplus heat.
Tier 4 engines
The Tier 4 category is known for its adherence to EPA guidelines regarding emissions control. But Tier 4 engines – often manufactured by leading brands like Caterpillar and John Deere – also provide fuel efficiencies that can save you on the total cost of ownership for a diesel-based air compressor.
Many of the top air compressors that incorporate Tier 4 engines are easily capable of 300 to 425 cfm at 100 to 200 psig. They feature advanced electronic control systems that include easy-to-read gauges and an LCD display, allowing the user to quickly adjust specific factors to achieve the optimum combination of performance and cost-effectiveness.
Though not standard to all, some models further extend their value through design enhancements. These can include a frame engineered for full fluid containment as well as easy access service doors that simplify service and maintenance for the fuel tank, engine, air filters, and other vital compartments.
Greater capacity, lower power requirements
The goal of almost every technology is to produce more with less. Air compressor manufacturers have pursued this goal by delivering ever higher levels of output on less fuel. One way they do it is through lower operating temperatures. By redesigning their compressors with lower internal temperatures, new models provide noticeable improvements in volumetric and electrical efficiencies.
Another aspect is seen in a trend we covered above: variable speed drive. Consider for example a rotary screw air compressor. Often integrated into woodworking and spray painting operations, auto body service and repair shops, and even larger industrial operations, they are often not a continuous use machine that has to operate at full capacity. In these situations, a variable speed drive is able to compensate for shifting power demands and monetize them – saving fuel, not to mention unnecessary wear and tear on machine parts. As mentioned above, this technology can reduce energy costs by more than a third, with some variable speed compressors even capable of operating on 40% less energy than their standard counterparts.
Oil-free rotary screw compressors
Essentially maintenance-free, oil-free or “oil-less” air compressors are permanently lubricated through a long-lasting treatment of Teflon or a similar synthetic resin. While oil free models aren’t ideal for continuous use applications, they’re great for short duty and home use. They’re also becoming one of the preferred types for spray painting outfits and other operations that require clean work environments. The reason is that oil-lubricated compressors discharge a small amount of oil in the form of mist, a design limitation that makes the mess difficult for some applications.
In addition to maintenance costs that are practically non-existent, oil-free compressors also tend to be less expensive due to a design that requires fewer parts. This minimalist design also makes them lighter, great for those needing portability.