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Newsletter 2005 issue 2 |
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Giving paint the blow off
K-Bar Industries, Inc., Faribault, wanted to reduce the non-value added cost of sending racking fixtures out for burnoff.
Master hooks hang 20 to 30 inches from the powder paint line conveyor. They hold three-foot long racking bars which part hooks are hung from. Because these racks attract powder paint during the electrostatic coating they had to be removed after each run and sent for burnoff.
This past year the company installed air jets that blast air across these top two fixtures, blowing off the loose powder after paint is sprayed onto the parts. By preventing paint buildup on the fixtures, fewer racks need to handled and sent for burnoff.
The compressed air jets are activated by a photo eye as the parts pass. The jets are carefully aimed at the top two racking fixtures so they do not blow paint off the parts being coated. The blown-off powder can be reclaimed for reuse.
If the jets are not out of the way, they can be hit when large parts are run. The jet system was designed to “break away,” moving on a spring loaded arm, to prevent it from breaking or damaging parts on the line.
Boyd Jones, of K-Bar’s industrial engineering team,
designed and built the jet system. Although the system is still considered in development, it is working well. Periodically, the line operators need to manually adjust the air jets.
“This work was an offshoot of having a MnTAP intern here,” said Dann Henseler, industrial engineering manager. In 2002, a MnTAP intern helped the company save over $44,000 by reducing paint waste and burnoff.
The additional energy used to power the compressed air jets is offset by the amount of paint that can be reclaimed. Henseler estimates that labor costs to manage paint-coated racking is reduced by $40 a day and burnoff costs are reduced by $100 a day.
Evaluating compressed air use
Compressed air is probably the most expensive form of energy available in a plant, according to the U.S. Department of Energy.
K-Bar verified that compressed air was the right choice for its application. But, compressed air is often used when other options would be more economical. For example, instead of using compressed air to aerate tanks, use mechanical means. For cooling, use fans.
Site visit—cooling the compressor
Metropolitan Council Environmental Services asked World Aerospace Corporation if it could reduce its wastewater. When investigating how to reduce wastewater from cooling the air compressor, the company asked Kyle Bartholomew, MnTAP engineer, to evaluate its air compressor system, with two compressors and a dryer.
The company uses an air-cooled compressor nine months of the year, and a water-cooled unit during the summer because it doesn’t put off as much heat as the air-cooled unit.
Using the company’s measurements, Bartholomew helped evaluate payback for closed loop cooling—too expensive for the size of World Aerospace’s compressor. Based on his research, the compressor needed to be at least 75 to 100 horsepower to justify a closed loop system.
“Kyle helped me figure out if I had options and what they were,” said Kim Phelps, director of special projects and safety at World Aerospace. “Now I’m looking into new, more efficient equipment that can save us money on water coming in, on water going out and on power to keep the system going.”
To evaluate if your company is using compressed air efficiently and to identify alternatives to using compressed air, call MnTAP for assistance.
Links
K-Bar Saves Over $44,000 by Reducing Paint Waste and Burnoff Improved inspection of reject parts before stripping, increasing operator awareness and process changes save K-Bar $44,000 annually. And an upgraded paint system reduced reject parts by 50 percent.
For more information about maximizing the energy efficiency of your air compressors visit MnTAP's energy Web page.
Compressed Air Workshops
Compressed Air Workshops can be found on Compressed Air
Challenge’s calendar page.
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