Engineering firm Bosch Rexroth was contracted by US-based metals industry equipment company Wooding Industrial Corporation to supply hydraulic components for a rotating materials distributor within a blast furnace for enhanced iron smelting capabilities.

Bosch Rexroth industrial machinery engineer Charles Erdo says this project is unique owing to the stringent specification on accuracy for an application with huge dynamic load changes. “The control system has to react fast enough to maintain a tight cylinder stroke tolerance between four differential area hydraulic cylinders.”

Bosch Rexroth’s solution, which is based on hydraulic engineering, commissioning and technology, comprises high-response directional proportional valves, electronic pressure transducers and control software for closed loop control.

Metallurgists have consistently sought to revise the centuries-old design of the iron blast furnace, with contemporary strategies aiming to enhance the composition of charge layers for increased production and efficiency.

Sinter and coke layers are created by an internal hydraulic distributor, using a chute located in the throat of the blast furnace to deposit raw materials in precise locations. The more accurately the chute can be controlled, the more precise the layers and the more efficient the blast furnace becomes.

Wooding Industrial Corporation’s end-user’s existing furnace distributor used a traditional hydraulic circuit with open loop control, offering only a limited degree of chute control for the distribution of large quantities of iron-ore pellets and coke.

The new hydraulic distributor underwent extensive accuracy and repeatability verification using the proprietary simulation tool, Modular Simulation of Hydraulic System (Mosihs), which allowed simulation of a virtual model including the overall hydraulic system. The simulations verified the hydraulic circuit design and that the selected Bosch Rexroth components were enhanced. In addition, the Mosihs simulation showed that control performance could be improved, using a specialised spool flow characteristic control valve.

Three hydraulic distributors using Bosch Rexroth hydraulic solutions were assembled, tested and shipped to China for installation.

Hydraulic equipment from Bosch Rexroth is distributed in Southern Africa by hydraulic components company Hytec Group of Companies.