Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/506694
the demand for air increases. The most popular sizes of these air compressors come integrated into their own trailer for easy tow- ing with a pickup. Larger units may be skid mounted or transported on fl atbeds, especially when you get into the bigger sizes for industrial applications like sand blasting. For a visual demonstration of how rotary screw air compres- sors work check out the YouTube video at: http://www.youtube.com/ watch?v=S08sj8pfJJs. Or just go to YouTube and type "How a Com- pressor Works" in the search box. Piston/reciprocating For smaller tools and applications that demand less air there are reciprocat- ing or piston style air compressors. Some of these are also engine driven, diesel and gasoline and some run off electrical power. Reciprocating air compressors use a piston to pressur- ize air and store it in a large air tank. These are typically used to supply air to nail guns, paint guns and some of the smaller impact wrenches that mechanics will use. Other than size and capacity, the main operational difference between reciprocating and rotary screw air compressors is that the stored air in reciprocating compres- sor's tank may run low and cause you to wait while it recharges. Your rental store can help you deter- mine the right size tank and proper horsepower needed for the tools you'll be using. Reciprocating air compressors once dominated the air compres- sor market, but because they have more moving parts, their service life was shorter and maintenance was more expensive. "If a reciprocat- ing compressor can operate in a given application without running extended periods and without too many start/stops, they are a good choice," says Eric Massinon, busi- ness development director for Chi- cago Pneumatic. "But if the applica- tion requires extended run times or a continuous load, then the rotary compressors are a better choice." Getting the size right Sizing a rotary screw air compres- sor to the application is a straight- forward process. There are two measurements to consider: cfm (cubic feet per minute) and psi (pounds per square inch). Simply add up the cfm requirements of any tools you'll be using simultaneously May 2015 | EquipmentWorld.com 34 maintenance | continued Underhood air that's always available If you occasionally need air but don't want to run to the rental store every time you do, take a look at VMAC's underhood air compressors. These are custom engineered to fi t in the engine bay of a wide variety of trucks including Ford, GM, Ram, Jeep, Mercedes, International and Sterling. They're powered by the vehicle's serpentine belt and you can get models that deliver 70 or 150 cfm and up to 175 psi. They're rotary screw designs that give you on-demand air and come with air- oil separators and oil coolers. http://vmacair.com. A single piece, lockable, lightweight canopy over Doosan's C185 air compressor is aerodynamic and impact resistant. The fenders and bumper are also made from high strength plastic and a three-step paint process resists corrosion and adds longevity. The unit produces 185 cfm. The VMAC Underhood70 installed in a 6.7L Ford Super Duty.