PRECISION UNDER PRESSURE

When Failure Isn’t an Option

In early 2013, the City of Cape Town faced a catastrophic mechanical failure at the Cape Flats Waste Water Treatment Works. One of four massive Archimedes screws—each lifting 500 liters per second into the gravity-fed sewerage plant—had suffered a complete top bearing collapse.

The situation was urgent. The plant’s capacity was compromised, and the failed screw, weighing 21 tons, posed a serious risk to reassembly and plant continuity.

That’s when TRA-COL Solutions stepped in.

Engineering the Impossible: A TRA-COL Response

The Challenge:

• A failed 600mm diameter roller and thrust bearing set

• A 6-ton Hansen H1 gearbox mounted at a 40° incline

• A 21-ton screw at risk of uncontrolled slippage

• A cold-welded 900mm jaw coupling fused to the top shaft

Our Solution:

• Designed and installed a custom-engineered holding jig to stabilize the screw without cranes

• Removed the gearbox and top bearing assembly with precision rigging

• Transported components to our partner workshop for full overhaul

Precision Machining Meets Engineering Insight

At the workshop, TRA-COL’s team executed a full mechanical resurrection:

• Recast and machined a new 900mm jaw coupling

• Manufactured and honed a hydraulically rammed taper sleeve to exact tolerances

• Performed hoop stress and friction force calculations to ensure torque transfer on a keyless shaft

• Rebuilt and reassembled the entire top bearing and shaft assembly

This wasn’t just repair—it was reverse engineering under pressure, executed with zero margin for error.

Twelve Weeks. One Mission. Full Recovery.

Despite the complexity, TRA-COL returned the Archimedes screw to full operation within 12 weeks of the initial failure report. The project demanded:

• Late nights

• Full team commitment

• Seamless coordination between site and workshop

And it delivered—on time, on spec, and with renewed confidence in the plant’s mechanical backbone.

Why TRA-COL Solutions?