Crane manufacturer and refurbishment specialist Condra has completed the manufacture of eight explosionproof, high-lift hoists for Tenova Bateman.

The custom-built two-speed machines will be commissioned at the Kusile power station to undertake installation and maintenance work on coal conveyors.

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, a Condra spokesperson says.

Loads of between 1 t and 7 t are managed by fixed lifting speeds of between 1.25 m a minute and 12 m a minute and lift heights of between 10 m and 41 m.

Four of the new machines are articulated, allowing travel around curves away from the line of conveyor movement, while higher-than-normal lift heights feature on six of the machines, with two machines boasting lift heights of 17 m, and the other four each reaching 18.5 m, 21 m, 32 m and 41 m respectively.

The remaining two hoists have 10 m and 11.5 m lift heights respectively.

“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,” the Condra spokesperson says, adding that the installed base includes lift heights as high as 150 m.

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 t, while open-drum units have capacities in excess of 250 t.

All the models include features such as electromagnetic direct current 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 the 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 m and more,” he says.

“The modular design of the K-Series allows rapid modification to specific high-lift application requirements. This includes lift speeds as quick as one metre a second – 15 times faster than the four metres a minute found in many standard applications – resulting in delivery times that are usually the shortest available.”

Standard hoist speeds go up to 18 m a minute.

Meanwhile, all the units have been flameproofed to IP65 standard and explosionproofed to Class II Zone 21 specification, countering the combustible nature of coal dust, which can explode if sparked.

“Among other things, the proofing involved fitting special gland seals between the motors and the hoists themselves and sealing all covers and panels,” the spokesperson continues.

Articulated crawls have been fitted with modified crossheads and assemblies that allow them to negotiate bends in the supporting I-beams, which follow curved routes to take the hoists and their loads away from the conveyor line.

Brass bushes on the articulation prevent any possibility of sparking.

During manufacture, all welds were inspected at every stage, and all eight machines were completed with a special anticorrosive paint specification.