When the Heart of the Shop Stops Beating
Air compressors are the heart of the automotive repair shop, so without the optimum technology, these shops face costly rework, high maintenance and replacement costs, exorbitant downtime—and very unhappy customers. This can make choosing the right compressor technology crucial, despite that with today’s technology, the preferences for a specific design might seem a bit argumentative.
But in collision repair, the continuous availability of unfaltering, high-volume compressed air is vital to support various tools as well as the filtered breathing air system.
“When the air goes down, we’re dead in the water,” says Sandy Muir, Caliber Collision Centers’ vice president of facility management. “Until we got the right compressor technology, I would get a call that one or two shops were down every day, waiting for service technicians to get them back up and running.”
With first class operations at Caliber’s 65-shop chain in Southern California and Texas running 24/7, having air compressor problems was unacceptable.
“This situation was intensified by our need for clean air, including providing a pure supply to our paint systems and tools as well as the breathing system that delivers fresh air via masks to our paint spray technicians,” says Muir.
Over the years, Caliber had used or evaluated several types of air compressor systems, including piston-driven models and rotary screw designs.
“Everybody is familiar with the old piston-style of compressor,” says Muir, “It’s a fairly simple concept, a piston running up and down and turning a crankshaft. But of course that motor also relies on intake and exhaust valves, which tend to wear and then leak.”
Caliber has also used rotary screw compressors, but was disappointed with the inherent volumetric and efficiency problems due to the “blow hole” and air leakage characteristics of those compressors. Moreover, in order to make up for inefficiencies and keep up air volume, designers of rotary screw compressors incorporate higher speed, which is detrimental to service life.
Most recently Caliber changed over to rotary vane compressors, a more sophisticated technology with one major moving part, which Muir says is more efficient and cleaner than the piston or rotary screw technologies. The vanes (or blades) are held outward by centrifugal force and a film of oil between the blades and the stator (housing) wall forms almost a perfect seal. The oil film also prevents direct contact between the vanes and stator, reducing wear to virtually nil.
Caliber’s rotary vane compressors come from Lans Company of Glendora, Calif., a major distributor of compressed air systems. Lans provides a selection of compressor technologies, brands and accessories, but when it comes to rotary vane compressors, the firm recommends the Mattei line.
“One problem with rotary vane compressors was the use of Bakelite vanes,” says Stuart Silverman, Lans Co. president. “But the Mattei models are cast iron, and because of the oil system, there is virtually no wear. I would say they last three times longer than the rotary screw models. Also, the Mattei rotary vane compressor uses no bearings, but instead use a bushing, so they last much longer than other models.”
Silverman adds that the volumetric efficiency of these compressors is about 90 percent, supplying a reliable continuous volume of air plus savings in energy, wear-life and maintenance costs.
Since installing the rotary vane compressors at every location, Caliber has experienced very few problems. “I may get a call once a month, which is music to my ears, compared with the two calls I used to get on the average day,” says Muir.
The new compressors not only meet the reliability requirement, but also have reduced the shops’ cycle time. Having continuously available compressed air that is consistently clean provides other advantages to those in the auto body repair business.
“Customers are driving more expensive cars with more expensive finishes in recent years,” Muir explains. “For that reason our industry receives continuous scrutiny from customers as well as stringent guidelines from agencies like insurance organizations and California’s Bureau of Automotive Repair. Paints have become very exotic and expensive. You don’t want to have to paint a car twice because of an air pressure problem.”
Rotary vane compressors such as the Mattei are easier to maintain and service, requiring fewer repairs and longer intervals than their piston or rotary screw counterparts. Assembly and dismantling of the compressor can be carried out quickly by using standard tools. Easy dismantling of the machine into subassemblies also makes fault diagnosis easy.
“We don’t normally perform any service on these compressors,” Muir says. “We have Lans handle all service throughout the air system, including air dryers and our breathing system. In our business, we know that air is the heart of it. When we call and say that we have an air problem, we need quick response and knowledgeable service.”