Dusty work

Demag Cranes & Components has installed a process crane from its BulkMaster range at a cement works in the UK.

Castle Cement's Ketton facility, in Rutland, produces more than 1.3m tonnes of cement a year. Production involves ground limestone and clay being passed through a kiln at temperatures of 1,450°C to form clinker. The clinker is then ground in mills with a small amount of gypsum and limestone to make cement.

As part of an upgrade and modernisation of Castle Cement's Ketton plant, Demag designed, manufactured and installed a fully automatic grabbing crane with an electro-hydraulic clamshell grab. Demag won the contract after Castle Cement had seen similar Demag cranes elsewhere in Europe. The crane at Ketton has a span of 24.4m and a safe working load of 12t.

The 'intelligent' crane system is controlled and monitored remotely. Its function is to ensure that the clinker arriving from the kiln is distributed in the store and that the hoppers feeding the cement mills are kept replenished. Sensors on the hoppers tell the control system that stocks are low. The crane then travels to where the appropriate material is stored, grabs the load and dumps it in the relevant hopper. The crane also feeds into the coal mill, supplying the kiln with pulverised fuel.

The environment of cement production is dusty and hot - ambient temperatures can be as high as 40°C. These are arduous conditions for sensitive machinery. The BulkMaster is designed to cope with these conditions and with the duty cycle application, operating all day, every day - 24 hours a day, seven days a week.

To cope with the amount of material that needs to be shifted, the crane has a hoisting speed of 100m/min and a travel speed of 120m/min. To avoid making this dusty atmosphere any worse, the crane 'remembers' the height of the last load that it dumped and unloads the grab gently onto the heap, minimising the amount of dust created.

"Demag has provided a technologically advanced solution, at a competitive price, which has increased productivity and helped us meet our environmental responsibilities," says Castle Cement's project engineer Howard Smith.