Bolting for Extreme Vibration Application

Vibration created by the large rotating cutter of a dredger is not a phenomenon readily overcome, if at all. It is a way of life that has to be worked around, requiring machinery to be built to best withstand the severe levels of oscillating shock loads that are encountered and ensure trouble-free operation and maintenance throughout the working life of a vessel.

When IHC of Holland were designing the 20,200kW cutter suction dredger ‘Al Sadr’ with a 26m cutting depth for the Abu Dhabi National Marine Dredging Company, the question of bolting the six, 6m long cutter shaft sections with 1m Ø flanges was a serious issue. A fact the vessel’s operator/owner were also aware of, engaging in dialogue with IHC to ensure a good solution was included to optimise the assembly and disassembly of the coupling shaft sections to eliminate the issues associated with ‘conventional bolts’.

Solution

PILGRIM Radial Fit Bolts provide significant and unique benefits. With the extremely accurate axial load and radial location generated by the bolt design and hydraulic actuation. Fewer bolts are required to ensure the long term integrity of each of the flange connections. Also the bolts provide a true interference fit once actuated but are installed and removed in a clearance condition. This eliminated bolt seizure and makes them easy to remove and reuse as many times as necessary throughout the life of the dredger when conventional bolting would require expensive replacements and bolt hole re-machining.

Benefits

  • Retrofittable solution
  • Reusable solution
  • No fretting
  • Elimination of seized bolts
  • Easy to install and remove
  • Safe and predictable