Your Guide to Selecting a Piston (Reciprocating) Air Compressor

In the global air compressor market, there is one major product type that has been used in the automotive and general industrial arenas longer than any other: piston air compressors. But don’t let the age of this technology fool you. In many cases, piston air compressors remain the perfect tool for the job. In fact, when most people think of air compressors, they likely have a piston compressor in mind. All piston compressors share a common quality: They use a crankshaft-driven piston to compress air, increasing its pressure and thereby its potential energy. Choosing the right one for your specific situation is a challenge because they are manufactured in a wide range of configurations and options. Here are five questions to consider before purchasing a piston compressor:

1. What size piston compressor is right for my business? Piston air compressors are available in a wide range of sizes, and it’s typically the application itself that is the most critical factor in determining the size air compressor you should buy. Larger units can generally deliver air at a higher cubic feet per minute (CFM) but are less portable; this means you’ll want to think about your need for portability versus your required CFM output. Piston compressors can also come with a horizontal or a vertical tank. While each delivers equal volumes of compressed air, a vertical tank can be a space-saver in smaller shops or other facilities where footprint size is important. Your choice will likely depend on whether space or location considerations exist in your facility.
   
   
2. What type of piston compressor do I need? If the compressor will be used indoors and generally remain in the same place, your best choice is likely an electric piston air compressor. These are the most common types of compressors used in auto-body shops, manufacturing businesses, and repair and maintenance operations. When ventilation is a concern, electric compressors are the appropriate choice because they do not produce emissions. This type of compressor also tends to be quieter than their gas-powered counterparts. When portability is a priority, a gas-powered piston compressor is the better choice because it doesn’t require a source of electricity. Gas-driven compressors are commonly used to power contractors’ equipment on work sites and repair trucks.
   
   
3. Should I choose oil-free or oil-injected piston technology? A major decision you will have to make is whether to use an oil-lubricated or oil-free air compressor. Oil-lubricated compressors, which leverage oil to lubricate and seal the compressors’ mechanisms and also to cool the compressed air, are suitable for a range of jobs in which traces of oil in the delivered air would cause no harm to the finished product. Examples include auto shops, woodworking and metalworking shops, as well as the majority of manufacturing, industrial and small workshops. Generally, oil-lubricated compressors are also quieter than their oil-free counterparts. But an oil-free compressor would be a better fit where delivering higher-quality, oil-free air is vital. This would include any application in which oil contact with the finished product would cause risk such as food production settings, paint shops, breweries, dental labs, and snowmaking operations.
   
   
4. Is the initial cost or lifecycle cost more important? Though more expensive at the onset, keep in mind that high-quality piston compressors use durable and long-lasting components. For example, a cast iron pump on a compressor will typically last longer than an aluminum pump featuring cast iron piston sleeves. Higher-quality compressors also typically have longer warranties (usually a minimum of two years). The best warranties will cover all compressor parts against anything that might go wrong rather than specific parts with a limited range of problems. And don’t forget noise and efficiency! Typically, higher quality piston compressors offer improved efficiency and reduced levels of noise.
   
   
5. Has my business outgrown its piston compressor? The key to finding the right piston compressor often hinges on the frequency and volume of the need for compressed air. If the growing operation’s air demand remains intermittent, switching to a higher-horsepower piston unit may adequately fulfill air needs. However, if a near-constant need for compressed air develops, a different compressor technology might be the better choice. If you find yourself asking questions like “Why is my piston compressor running all the time?” or “Why are my air tools not creating enough torque?,” then it’s time to chat with your local compressed air representative about the best technology for your business.

In addition to answering these five questions, a consultation with a compressor expert and a simple air audit can also be helpful in determining which model will be the ideal choice for your business and your budget. Find out more at www.atlascopco.com/air-usa!

About the Author. Katie Falcon is the contributing writer and editor for The Compressed Air Blog. She currently works at Atlas Copco Compressors as a Digital Marketing Specialist specializing in content creation and platform development. Reach her via email at katie.falcon@atlascopco.com. Eric Johanson acted as the technical contributor and currently works as a Product Marketing Manager at Atlas Copco Compressors. He can be reached via email at eric.johanson@atlascopco.com.