In early June of 2002, SECO/WARWICK received an order for a new Ingot/Slab Reheating and Homogenizing Pusher furnace from C. S. Aluminium Company located in Kaohsuing Taiwan.  The new furnace will incorporate many unique features and services, which will draw upon SECO/WARWICK's 35 years of experience in designing and building ingot pusher furnaces.

Capacity

The new furnace is an expansion of the existing furnace capacity. The furnace will be rated for 450 metric tons and will process 580 mm thick x 4,700 mm long x 2,300 mm wide ingots/slabs. The furnace will be designed to provide fast heating time with tight temperature uniformity in the most efficient manner possible to reduce natural gas and electrical consumption, a critical concern for C. S. Aluminium.

SolidWorks® 3D CAD Design Capability

For this project, SECO/WARWICK introduced a new engineering software program called SolidWorks®. This software offers 3D design capability for checking interferences and movement of mechanical devices. Check out this eDrawing of the down ender device at the discharge end of the material handling system-SolidWorks® allows you to zoom, rotate and animate the image.  Keep in mind that this down ender will handle 38,000 pound ingots.  SolidWorks® is a registered trademark of SolidWorks Corporation, Concord, MA.

Material Transfer

Another unique feature of the furnace is the ingot shoe return monorail system. This device removes the extracted shoes and transports them via a monorail system to the charge end of the furnace for use in the next charged ingot. This device is PLC controlled and will adjust its shoe extraction and placement depending on the size of the ingot.

The system will include an ingot/slab handling system which consists of a charge table which centers the ingot, measures and weights the ingot and sends the measured information to the control system. At the final stage of the charging system, the ingot is upended and placed on the ingot shoes and pushed into the furnace. Once processed, the ingot is extracted out of the furnace and down ended directly onto the existing rolling mill transport table. This eliminates any additional transport equipment.

Heat Transfer and Energy Efficiency

To improve heating time and temperature uniformity, a vertical air flow design is being used through the use of roof mounted centrifugal fan. These fans are controlled by belt driven motors with variable frequency control drives for the most efficient speed control and reduced power consumption.  Since airflow is critical to the heating of the ingot, movable side baffles will be used to insure that there is no air bypassing when varying length ingots are processed. These side movable baffles will be adjusted automatically by the PLC based on the ingot size information obtained at the charge table measurement devices.

To improve natural gas efficiency, high efficient direct-fired natural gas burners will include plate type recuperators to provide high-preheated combustion air temperatures. These recuperators will be installed in each of the five heating zones.  In addition to the high efficient burner system, heat loss was another major concern that contributes to natural gas consumption. This was critical in two areas, one was the heat loss through the shell of the furnace and the second was the opening of the charge and discharge end doors during ingot charge or discharge.  

To handle the heat loss through the furnace shell, SECO/WARWICK employed our multi-layer of ceramic fiber insulation with the mesh and mortar system. This system will insure low heat losses through the furnace shell.  The second loss was handled through the use of inner doors at the charge and discharge end of the furnace. These inner doors will contain the heat inside the heating area of the furnace during charge and discharge cycles. The exterior door opens to charge or discharge an ingot. Once inside the vestibule, the exterior door closes, and the interior door opens to accept or discharge an ingot. The use of these doors will eliminate large amounts of heat loss during these charge and discharge cycles.

An ingot cooling system will also be supplied to meet specific rolling mill temperature requirements after the final heating or homogenizing is completed.

System Controls

The control system will be driven by a state of the art  PLC with SECO/WARWICK programmed graphical user interface. The furnace temperature control will consist of both air thermocouples and ingot surface measuring probe thermocouples. The control system will be a ratio type with the use of heating head to control the ingot temperature. Not only will a main control panel be installed, two additional operator will mount stations at the charge and discharge end of the furnace for operator control.

Manufacturing Partnership

The contract with C. S.  Aluminum also required SECO/WARWICK to supply not only critical equipment from the US, but also the fabrication and installation of the project. To handle this local Taiwan portion of the contract, SECO/WARWICK selected China Steel Machinery Company, a sister company of C S. Aluminium. The China Steel Machinery Company is located about 3 miles from the actual jobsite and has fabricated many similar types of similar steel equipment. The union of our three companies should prove beneficial to all parties.

12/12/05 R1 Removed author reference