Barnhart was hired to remove and replace fuel heat exchangers at a nuclear plant in Wisconsin. The 14,750 lbs. vessels had to be maneuvered in a small space. To overcome the tight tolerances, the engineering team had to design a system that allowed for maximum flexibility, yet could be constructed using no overhead rigging.
Every 1/16” mattered when it came to doing field measurements, so the team also performed a laser scan of the space. Field verification in conjunction with laser scan data allowed for engineering to build a very accurate model of the site. Every detail in the model had to be correct, from the height of shimming to how far the bolts stuck out on the heaters.
The team designed a system using pull-up jacks and Hillman saddle rollers. The jacks underneath the slide beams allowed Barnhart to change the height as required to get under pipes and over foundations and to tilt if needed. The custom-designed rollers allowed the field crew to rotate the vessel along its longitudinal centerline to further avoid obstructions. The heater also had to be repositioned several times, so a roller that could be broken down quickly and moved was a key aspect of the saddle design.
Because of the space constraints, the project engineering plan took several iterations to complete a thorough and efficient design. But the preparation and planning paid off with a project that was successfully executed.