The Evolution of Power

According to Marc James, product manager for compressors at Ingersoll-Rand, the highest-tech compressors are the larger models, those 900 cfm and up. This is mostly due to their use of larger, more sophisticated engines that meet the latest emissions regulations and offer a lot in the way of electronic advancements.

“Technology will come to the smaller machines,” he says, noting that the average 185-cfm compressor currently uses a Tier-II compliant engine and is not scheduled to meet Tier-III requirements until 2008. “They might not go all electronic, but the capability is there.”

With regard to engine technology, manufacturers are working to make their compressors more energy efficient. Kaeser Compressors, for example, offers a 185-cfm unit (the M57) that produces 210 cfm at 100 psig while only using 45 hp. According to Chartters, competitive units require about 49 hp to produce only 185 cfm.

“We have selected larger airends that turn at much lower speeds. This increases the air output while significantly reducing the horsepower — and therefore the fuel consumption,” he comments. “And with today’s fuel prices, this can have a huge impact on daily operating costs. Rental houses that offer more fuel efficient equipment definitely have an advantage when bringing customers in.”

In addition to consuming less fuel, the M57 also features an extra-large gas tank. The combination of the larger airend and larger fuel tank combine to provide a run time of over 10 hours, Chartters says.

Today’s compressors, like generators, are getting smaller. Manufacturers are working to streamline their designs to make units easier to service and troubleshoot. In tandem with this trend are efforts to make the machines more lightweight, yet durable.

Ingersoll-Rand, for example, recently introduced a new canopy made of a composite material instead of the traditional steel. Technically referred to as thermal plastic polyolethin (TPO), this canopy is lighter while offering good temperature flexibility and resistance to dents and rust. James notes that older I-R compressors using traditional enclosures weighed in around 2,400 lbs., while TPO models tip the scales at only 1,850 lbs.

“The TPO canopy is used on three models: the AirSource, a 160-cfm machine; the AirSource Plus IR and AirSource JD, both 185-cfm models,” he says, noting that AirSource Plus models are available with either Ingersoll-Rand or John Deere engines, hence the IR or JD nomenclature.

Ingersoll-Rand and other manufacturers also use what is referred to as “cool box design.”

“The engine and heat exchangers are turned 180 degrees so they’re in front,” James explains. “Vents on the side rear draw in fresh air which passes through the machine and goes through the heat exchangers, minimizing dust and contamination while keeping internal temperatures low.”

In addition, serviceability is improved by offering such features as a 90-degree access canopy, clean wiring and a remote, spin-on separator element. “In the past, this used to be located in the separator tank, so it was hard to change the filter,” says James. “The filter is now outside the tank. There are no bolts, no need to get into the separator tank.”

He continues, “In rental, it’s all about utilization and how quickly you can service the equipment and get it back on rent.”

Gauging performance

One design criteria that affects both generators and compressors is the issue of controls and gauges. Technology has made it possible to produce some very sophisticated digital controls that provide myriad data. For example, Wacker generators feature a digital engine generator control module (EGCM) with LCD display. This “behind the scenes” computer monitors engine and generator performance and outputs data to the LCD display in simple, easy-to-understand numbers, says Leupi at Wacker.

“With the EGCM/LCD, Wacker has been able to eliminate the need for many analog gauges, switches, indicator lights and the necessary complex wiring to tie it all together,” he says. “This simplifies the layout and makes it easier for a variety of users from different industries to understand and operate the generator.”

Still, other manufacturers have chosen to go another route and stick with analog gauges.