concretesubmarine.com/ FORUM

The double-girder electric overhead travelling crane will replace an existing machine from a European firm. It will become Condra’s second to work at Feed Three, joining a single-girder overhead crane manufactured by Condra in 1984.

The crane has been designed to incorporate three hoists: a 25-ton main lifting unit and two 12.5-ton auxiliaries, all of them mechanically synchronised for tandem operation as well as offering individual lift.

Able to service all machinery on the dryer line’s floor area of 80x25m, the crane’s 25m span will deliver a maximum capacity of 50 tons and a lift height of 16m. Alternatively, the crane will lift up to 25 tons using the main hoist while, simultaneously, two independent loads of up to 12.5 tons can be managed by each auxiliary.

The crane’s load lifts are failsafe, its three hoists fitted with secondary emergency brakes on the rope drums to back up standard brakes on the electric motors.

Condra says it undertook the contract as a turnkey project that will include installation through the plant’s roof. Manoeuvrability on the dryer line floor is limited by in situ machinery, it added, making conventional access and installation impossible. Production will continue uninterrupted while installation takes place.

Three Durban-based companies will work as subcontractors to Condra. They are Yellow Dot Coatings, Lovemore Bros, and Natal Cranes. All components of the new crane, including end-carriages, 25m-long box girders, crabs and hoists, will be lowered through an aperture in the plant’s roof and positioned for in-situ crane assembly.

Yellow Dot Coatings has been appointed to open the plant’s roof, after which Lovemore Bros will rig all components and use its 550-ton mobile crane to luff them one by one above and through the roof opening, lowering them into position for crane assembly by Natal Cranes, Condra’s Durban-based agent.

After installation, Natal Cranes will also oversee commissioning.

Five companies from Europe and Africa submitted tenders for the contract. The proven reliability of Condra’s existing installation is thought to have reinforced a competitively priced bid to secure the turnkey contract.

Condra’s electric overhead travelling crane was ordered as part of 7.7bn rand upgrade and expansion of Saiccor Mill, a dedicated dissolving pulp plant, owned by Sappi, a global provider of everyday materials made from wood fibre-based renewable resources.

Dissolving pulp is a key input in textile manufacture, food processing and pharmaceutical production.

The pulp dryer line to be serviced by the new Condra crane is noted for being a corrosive environment resulting from the use of steam-heated drying cylinders to dry the sheet-form pulp ahead of packing and shipping.

Manufacture of the crane from carefully selected materials and the use of anti-corrosion finishes will afford protection. All motor and electric panel insulation has been protected to Standard IP65, while the panels themselves and all handrails are of stainless steel. Crane platforms have been fitted with fiberglass grating instead of steel chequer plate, and all crane components coated with a special anti-corrosion finish.

Sappi’s new crane is scheduled for commissioning at Saiccor Mill early in 2024.

Condra manufactures service and maintenance crane for dissolving pulp plant