Explosion-proof hoists for Kusile coal conveyors


CONDRA has completed manufacture of eight explosion-proof, high-lift hoists – four of them articulated – for Tenova Bateman.

All are custom-built, two-speed machines that utilise the modularity of Condra’s K‑Series to deliver performance capabilities precisely tailored to the individual requirements of each application.

After commissioning at Kusile Power Station, the eight machines will carry out installation and maintenance work on coal conveyors. They will further boost Condra’s already substantial presence at Kusile, where the majority of overhead cranes and hoists have been supplied by this company.

Lifting capacities, lifting speeds and lift heights vary greatly among the eight hoists.

Loads of between one and seven tons will be managed by fixed lifting speeds ranging from 1,25 to 12 metres per minute, and by lift heights of between 10 metres and 41 metres.

Noteworthy among the machine features is the articulation on four of them, allowing travel around curves away from the line of conveyor movement. Also unusual are the higher than normal lift heights on six of the units: 17 metres (two machines), 18.5, 21, 32, and 41 metres.

A Condra spokesman explained that even the 10 and 11,5-metre lift heights of the remaining two hoists can be looked upon as high-lift.

“Hoists with this sort of lift height are not off-the-shelf deliveries for most crane companies, but we can offer and deliver a high-lift capability quite quickly because of the modularity of the K-Series,” he said.

“We can adapt the K-Series to an extremely wide range of requirements.”

The K-Series is produced in three configurations: foot-mounted, monorail and double-rail crab. Lifting and reeving arrangements include centre-lift.

Fully covered hoists provide lifting capacities to 32 tons, while open-drum units have capacities in excess of 250 tons.

Features on all models include electromagnetic DC disc brakes, standard frame-size motors with parallel rotors, double-acting limit switches, solid bronze rope guides and totally enclosed splash-lubricated gearboxes.

Condra uses silumin rotor cores to enhance K-Series motor-starting torque in the high-lift role, and offers optional variable speed control on the drives to enable precise load positioning even on lifts of 100 metres and more.

The modular design of the K-Series allows rapid modification to specific high-lift application requirements (including lift speeds as quick as 1 metre per second – fifteen times faster than the 4 metres per minute found in many standard applications), resulting in delivery times that are usually the shortest available.

Standard hoist speeds go up to 18 metres per minute.

After delivery, the hoists for Tenova Bateman will be installed in the coal silos and at various maintenance stations along Kusile’s conveyor route, where they will help with the installation, removal and maintenance of motors, gearboxes, rollers, pulleys and the conveyors themselves.