A leading construction company has taken delivery of two Condra 60-ton portal cranes for its pre-cast yard in Port Elizabeth.
The twin Class Three machines, each one weighing approximately 52 tons, are very large cranes with 30-metre spans and 9-metre lift heights. They will be used for the manufacture of reinforced concrete columns for coastal wind turbines.
Long-travel speeds of between 20 and 60 metres per minute are considerably faster than would be expected for portal cranes of these dimensions. The customer has the option of control either by remote or by conventional pendant.
Contact value was approximately R10-million.
During the design phase, special attention was paid to wind loading because of the large surface area of the girders. The machines are fitted with anemometers and Condra’s patented storm brakes to prevent them from being moved by the force of extreme winds. The anemometers will activate safety devices in two stages, first sounding a siren at a wind speed of 50 km/h, then automatically engaging the storm brakes at a wind speed of 70 km/h, overriding crane operation and securing the machines against further movement.
Crane design also took transportation into account, with the size of the top frame necessitating manufacture of each girder in two parts to enable road delivery by associated company Transcon Haulers.
The separate girder parts have already been bolted together ready for installation and commissioning.
Condra’s factory in Germiston, where these portal cranes were made, provides leadership and design guidance for sister factories in Cape Town, Bulgaria and Chile. The four factories together produce hoists, end-carriages, single‑girder and double-girder overhead travelling cranes, portal cranes, bridge cranes and cantilever cranes for markets worldwide.
The Condra group maintains a very tight focus on quality and rugged reliability, with all cranes designed and assembled to specification from hoists, drives, end‑carriages, brakes, gearboxes and some 250 other sub-assemblies produced in-group.
Two lines of hoists are manufactured in a number of standard models suited to most mining, industrial and general applications, from 1 to 500 tons. Motors are bought from external suppliers.