VTI helps historic Knoxville company leak-test bellows for wind turbines

The Fulton Bellows company manufactures high-quality precision metal bellows that perform critical functions in everything from automobiles to airplanes. But to function properly, each of these elastic metal cylinders must maintain an airtight seal strong enough to withstand dramatic changes in temperature and pressure.

To help Fulton Bellows leak-test two new bellows assemblies, a team of engineers at Vacuum Technology Incorporated (VTI) designed and built custom leak-test fixturing perfectly tailored to fit into Fulton’s established production process. The fixturing, which features two leak-test chambers and a tubular steel frame assembly, can detect leaks as small as 5×10^-9atm-cc/sec of helium from 800 psig into vacuum. Fulton Bellows will use their leak-detection system to perform quality-assurance checks on bellows assemblies that will serve as gas and liquid valve stems in wind turbines.

“We needed a system that could detect leaks in these new products without making us rethink our entire method of production. VTI helped us solve that problem, and we’re excited to integrate this leak-detection system into our production process,” said Kelly Ferguson, Manufacturing Engineering Manager at Fulton Bellows.

To leak-test a candidate bellows assembly, an operator fixes one of two custom leak-test chambers to the tubular frame assembly, inserts the candidate part into the selected leak-test chamber, and places the interior of the bellows under vacuum. Once the unit is under vacuum, the operator then charges the exterior of the bellows with pressurized helium. A mass spectrometer will alert the operator if any helium passes through the candidate bellows assembly, which suggests the part has a defect. The entire process takes less than a minute and can be completely automated.

“Making sure the leak-test chamber seals perfectly to a customer’s product is one of the hardest aspects of custom leak-detection,” said Aaron Powers, a VTI engineer who helped design Fulton Bellows’s system. “In this case, we created two distinct leak-test chambers, each of which is interchangeable to the same frame and tailored to fit either the liquid or gas valve bellows assembly.”

VTI fabricates each of its products completely in house, making it easy for customers like Fulton Bellows to receive high-quality parts crafted to suit their unique needs. And with over three decades of experience designing and building custom vacuum systems, VTI is uniquely well-suited to solve even the most complicated vacuum and leak-testing problems.

“It’s pretty rare for a company to have both the necessary expertise for designing effective vacuum systems and the fabrication capabilities required for building those systems from scratch,” said Powers

For Fulton Bellows, which has over 100 years of experience doing business in Knoxville, Tennessee, getting to collaborate on a project with another long-standing local business is always a pleasure.

“We enjoyed working with VTI on this leak-detection system, and we look forward to doing business with them again in the future,” said Ferguson.