Waste Heat Boiler Scale Removed from U Bend

Agricultural plant U bends cleaned remotely with Flexiburr

The usual heavy expense of re-tubing was avoided when Tube Tech applied an innovative technical approach to remove scale from a waste heat boiler at the agricultural fertiliser plant.

The Challenge

  • A previous attempt at cleaning the tube internals at the site had resulted in a conventional semi-rigid lance becoming jammed. Furthermore, ball bearings used to assess the severity of the problem at the ends of the tubes had not been recovered due to deposits in the U bend.
  • The unit, (equipment number H1210), which runs at high temperatures and under extreme pressure, could not go back into service as the deposits were likely to cause hot spots.
  • All work had to take place within the channel/waterbox-cover with the only access through 17” and 20” inlet/outlet holes. Working in a restricted environment with conventional high-pressure water jetting techniques would have been potentially dangerous for the equipment operator.


  • Via a 16-metre, small diameter video inspection probe plus biopsy sampling forceps, Tube Tech assessed the extent of contamination which revealed loose particles in the entire tube length and hard scale clinging to the bends.
  • First Tube Tech successfully extracted the lance and test ball bearings.
  • The subsequent cleaning process involved a combination of three of Tube Tech’s own innovative techniques. Tube Tech’s specialised Flexiburr system was developed further to ensure the bends were as thoroughly descaled as the rest of the tubes without tube damage. The company’s SafeFlex equipment, incorporating a Tube Tech-designed, remote safety boss, provided the flexibility needed and eliminated the risk of injury to an operator working with pressurised water in a very restricted environment.


An Engineer explained: “Traditional methods would not have cleared the problem. If it had not been totally resolved, it could have led to failure on line which would have been a lot more expensive than paying for Tube Tech’s expertise. We worked through several options with Tube Tech to find the best solution.”

Images and videos associated with this project are available via Tube Tech International
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