It may sound like the name of an elite air force squadron, or the next film in the “Dirty Dozen” series. But in actuality, the “Dirty 30” is more like the movie “The Green Mile”, as it stands for the final distance in compressed air systems between the main distribution headers and the operating equipment.
Extremely poor installations definitely demand greater compressor discharge pressure if they are to function properly.
Though certainly capable of occurring anywhere — on the supply as well as demand side — leaks and pressure drops are most prevalent within this last 30-foot stretch. Having recognized the importance of improving compressed air system efficiencies in modern manufacturing plants, engineers and energy conservation proponents have focused on these two factors, devising new solutions to eliminate leaks and reduce air compressor pressure to the lowest set-point possible. Since these two energy-wasting problems are typically most prevalent within the “Dirty 30”, it’s a prime source for savings. And fortunately, there are ways to combat both problems and realize both greater efficiency and profitability.
Pay attention to the sizing of components between the air header and the end uses
When operating positive displacement air compressors in the 100 psig range, every two percent decrease in operating pressure requires about one percent less input power. To prevent excessive pressure drop, compressed air lines should be sized based on maximum anticipated “rate of flow” not simply the average flow.
Point-of-use filters, regulators, and lubricators — known collectively as FRLs — provide a clean, stable, and lubricated compressed air supply. All too often, we find FRLs being undersized for the maximum rate of flow. Under-sizing any of these components, or sizing them solely on pipe-thread size of other connected components, will result in an increased pressure drop. In addition, timely maintenance, or replacement of point-of-use filter elements, is critical to minimizing or reducing pressure drop.
Another common high pressure drop point is at quick disconnects. These are used to transition from hard piping to hose, and at the final connection to the operating equipment or tool. However, standard quick disconnects can create problems of their own.
A better, proven alternative is a version with a full-port design. These disconnects are similar to a full-port ball valve. The internal orifice is the same size as the pipe thread size and doesn’t have a ball and spring to introduce pressure drop.
Proper sizing of components between the air header and the tool will pay dividends in lower energy cost.
As stated earlier, leaks can occur anywhere in the compressed air system. However, because of the numerous components and fittings typically used to connect the operating equipment to the air header, the Dirty 30 is a prime candidate for leaks. So logic demands this be a major focus in the efforts to conserve energy and generate cost savings.
The hard-blowing truth is, compressed air is often the most expensive utility used in a manufacturing plant. However, paying close attention to the Dirty 30 as part of an overall compressed air energy savings program can reduce energy costs, thus increasing your operating efficiency as well as your company’s bottom line.
A recent article co-written for The Compressed Air Challenge by Scales Industrial Technologies’ COO Niff Ambrosino and General Manager Paul Shaw goes into far greater detail on ways to maximize compressed air system efficiencies. To learn more about cleaning up the “Dirty 30” in your company’s system, read the full article by clicking here
