Redesigning a screen hopper to fit through the plant
A worn-out hopper that had been built in place, was bigger than any opening in the plant, and couldn't easily be trucked in under new power lines. Replaced in a time-limited shutdown with no special equipment.
01Project description
A screen hopper had undergone severe wear and was due for replacement. Initial scoping discovered that the hopper was built in place during the screening plant construction. This resulted in the hopper being larger than any opening in the plant and would require extensive dismantling of the plant structure to remove and replace. The replacement hopper was also difficult to transport to site due to new high voltage power lines that had been installed along the route. A solution was required that would minimise the work needed to replace the hopper during a time-limited shutdown.
02Solution
The site construction drawings were used to model the structure to give an understanding of the existing constraints to handling the hopper through the plant. The OEM hopper drawings were used to model the hopper to detect the existing clashes. A site visit was used to verify the critical dimensions found in the construction drawing study.
Once the maximum passage sizes for conventional handling methods were determined, the hopper was examined to see if a redesign to fit these constraints was possible. It was found that the hopper could be split into three sections that would enable easy handling and transport.
03Outcome
A design in three sections was created that could be handled and assembled with conventional methods. A work instruction was also produced for the demolition of the old hopper and the installation of the redesigned hopper. This assisted in the allocation of time and resources by the site planners.
The shutdown went as planned with no requirement for specialised equipment or extra personnel. Future hopper replacements are now a known and documented quantity.