The LP350 was utilised by heavy lifting and specialised rigging business, Irving Equipment.
Affiliated company Irving Tissue, a tissue production firm, had a requirement to remove a 55-ton dryer and replace in kind. Both systems were 12 ft. 5 in.-diameter and 13 ft. 4 in.-long cylinders with 4 ft.-long shafts sticking out of either end and Irving was responsible for all movements of the outgoing and incoming units.
Ryan Long, operations manager for southern New Brunswick and Nova Scotia at Irving Equipment, explained that the scope of work presented four standout challenges – travel route, second floor location of the dryer, floor strength, and tight confines for blocking up the loads.
In addition to the LP350, Irving employed an Enerpac EVO power pack system and four 50-ton capacity jacks for vertical jacking of the dryer; a pair of 8-ton capacity Broderson carry decks for material handling; and a 250-ton capacity Liebherr LTM1200 all-terrain crane.
Since the dryer was a primary component of an existing in-line paper machine, Long said that it was deeply embedded within the plant and required the project team to make three directional changes and three elevation changes to avoid existing infrastructure.
He added: “As the dryer was on the second floor of the plant, in order to get it to ground level a temporary mezzanine was designed and installed outside of the plant at the same elevation as the sliding system, and the back wall of the plant was removed. This allowed us to slide the dryer completely outside of the building and onto the mezzanine before lifting it off with our Liebherr LTM1200.”
It was determined that the concrete floor of the building could not support the loads that would be imposed by the dryer as it travelled along its path. To mitigate this, a steel grillage system was engineered and installed to bridge the floor between supporting columns under the floor for the entire route. Since the dryer removal was part of a larger overall shutdown, the grillage system had to be installed in a sequence that didn’t impede that scope of work.
Innovative solution
The underside of the installed dryer was approximately 5 ft. off of the floor, which made for a considerable amount of blocking to be done when lowering it down to the floor.
Long explained: “Combined with the awkward 5 ft. of space, we knew it would be time-consuming and hard on the rigging crew to do all of that work while hunched over. It screamed soft tissue injury so, to overcome this, one of our team members hatched the idea for a very clever ratcheting jack-post design that eliminated the need for blocking.”
The LP350 eliminated the need to remove a roof section and lift out the dryer with a 500-ton capacity class crawler crane. The Hydra-Slide system was compact and easy to use within the tight confines of the plant. The method also facilitated the three required directional changes in 31 ft., 38 ft., and 135 ft. increments, with the aforementioned elevation changes along the way.
The slides took place across two 12-hour shifts. Outside, the LTM1200, part of Irving’s fleet of 100-plus cranes, lifted the dryers with a Modulift spreader beam beneath the hook and slings basketed around the dryer shafts. The paper machine was shut down whilst the dryer was being replaced.