When a major municipal sewage treatment facility approached TriStar, they were searching for a more durable and cost-effective alternative to the PET bearings supporting their Archimedes screw. These bearings support the shaft at both the upper and lower ends of the inclined screw, where load conditions vary due to cantilever forces. The goal: longer lifespan, better resilience, and lower overall cost.
The Archimedes Screw – A Proven Design for 2,259 Years (and Counting)
The Archimedes screw, a marvel of ancient engineering, traces its roots to ancient Greece and Egypt and was first recognized in writings from around 234 BC. Initially developed as a tool for lifting water, its earliest recorded use involved irrigation systems along the Nile River. The original design consisted of spiral tubes wound around a cylinder. As the cylinder was rotated by hand, water was lifted from the river into irrigation ditches. While the basic concept has endured, today’s screws see expanded use in diverse applications and rely on modern materials for performance and reliability.
Extreme Environments Call for Extreme Materials
At this facility, the Archimedes screw operates partially submerged in sludge and wastewater at the lower end, with splash exposure at the top. The sewage is often coarse with sediment and contamination in the form of rocks, tree branches, and anything else (like car parts!) that can find their way into the average city sewage system. In addition, temperatures at the plant can run from near freezing to 100+°F. This level of abuse demands a bearing material that can thrive where others fail.
Enter Ultracomp UC300AX
TriStar engineers quickly determined that our Ultracomp UC300AX would be the best solution as it loves being wet, sustains very high side loads, works extremely well in abrasive environments, can take impact loads from jam ups on the screw, and is very cost effective for the 4" shaft size.
Our team worked closely with the plant’s engineers to confirm fits, tolerances, and all operating conditions, ensuring long-term reliability.
Archimedes screws are also found in food processing plants (moving fruits, vegetables, dry goods like sugar and flour) and even in specialized pump designs. TriStar has many solutions for these different screw bearing applications so, as always, we encourage you to reach out to discuss with our team.