Bearings said to minimise maintenance

Bridge

As resources and materials handling projects expand or reopen in line with commodities prices, operators face the challenge of building new bridges, conveyor overpasses and supporting pipelines to carrying heavier throughputs – or bolstering the capacity of existing overpasses and conduits.

Supporting the fluctuating loads carried by conveyors, trucks and machinery imposes demands on the structures supporting them, which must function reliably across a spectrum of shock, impacts and widely varying thermal loads in situations varying from remote Outback facilities to busy port and coal loaders.

One solution to the issues of cost-efficiently achieving reliable load-carrying capacity is provided by Hercules Engineering through its range of Herculon Type D Bearings (HLD/SG, HLD/FF & HLD/FX), which are widely proven on applications ranging from steel and concrete beam and pipeline engineering structures through to materials handling and processing facilities.

Compared with more sophisticated and expensive heavy alternatives, such as pot bearings and roller bearings, HLD bearings are said to offer lower initial cost, easier installation and no maintenance for periods of 30 years or more.

Available in standard configurations supporting 100-600 kN (60 tonnes) each, the bearings can also be custom-engineered to configurations that best suit installations and site conditions.

Recent pipeline support structures, for example, were used in the refurbishment of existing river crossings, using high-performance combinations of engineered thermoplastics and stainless steel facing surfaces that provide the necessary slip performance but don’t break down in the way that earlier types of bearings deteriorate.

The problem with many older joints – which are intended to prevent pipelines buckling or cracking as they are subject to shock and vibration or repeatedly heat and cool over many seasons – is that many older types of grease bearings have exceeded their lifespan, corroded, lost their flexibility and bound rigid. The new bearings, by contrast, were engineered to minimise maintenance and optimise service life by flexibly accommodating the thermal issues and the vertical and horizontal stresses imposed by the shuddering and vibration of varying loads.

Such performance and no-maintenance advantages were built into HLD/SGU bearings designed recently for conveyor overpasses to serve new Outback and heavy duty resource and bulk handling developments. These bearings were engineered from mild steel enclosing a sandwich of Teflon on mirror-finish stainless steel bonded to a special grade rubber sub-stratum.

“These particular bearings were designed with built in restraint mechanisms to ensure flexibility and excellent sliding characteristics in load carrying and thermal performance, but to prevent extreme movement that would compromise the bearing’s long-term performance,” said Mr Booty.

One of many Hercules sliding guided bearing types, which require no maintenance beyond regalvanising over decades

The bearings contained built-in guidance and uplift restraint that:

  1. Prevented excessive movement in the horizontal plane, while still allowing sufficient flexibility to tolerate side loads and the deflection needed to tolerate varying loads without breaking or buckling
  1. Prevented uplift beyond specified limits in the vertical plane, providing restraint when the structure on which they are mounted is subjected to extreme seismic and wind conditions, for example.

Herculon type D sliding bearings – incorporating polymers proven globally for outstanding durability without lubrication or maintenance – were developed to fulfil the need for low-friction bearings on corbels and columns where continuous slip joints were not appropriate. Herculon HLD Bearings are part of a comprehensive range of Hercules composite slip joints and structural bearings incorporating engineered high-performance combinations of engineered thermoplastics and stainless steel facing surfaces.

Type D Herculon Bearings (HLD/SG) are designed to accept a lateral load of 30 per cent of the vertical rated load, which can be up to 600 kN per bearing in stock sizes, with higher capacity available custom-engineered for specific applications. They are removable and replaceable, to optimise no-maintenance performance in access infrastructure and high output plant such as mineral processing and oil, gas and energy infrastructure and conveyors in applications extending from ports to power plants.