The Ingot/Slab Reheating and Homogenizing Pusher furnace from C. S. Aluminium Company located in Kaohsuing Taiwan has completed final start up and commissioning.

Capacity
The new furnace is an expansion of the existing furnace capacity. The furnace is rated for 450 metric tons and processes 580 mm thick x 4,700 mm long x 2,300 mm wide ingots/slabs. The furnace  provides fast heating time with tight temperature uniformity to reduce natural gas and electrical consumption, a critical concern for C. S. Aluminium.

Shoe Return Monorail System	Ingot Delivered for Processing	Ingot Centering Operation

Material Transfer
A 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 adjusts the shoe extraction and placement depending on the size of the ingot.

The system includes 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.

Upender Positions Ingot	Ingot Charged into the Heating Chamber	Downender Places Finished Ingot on the Discharge Conveyor

Heat Transfer and Energy Efficiency
To improve heating time and temperature uniformity, a vertical air flow design is 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 include plate type recuperators to provide high-preheated combustion air temperatures. These recuperators are 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 enables the finished product to meet the specific rolling mill temperature requirements after the final heating or homogenizing is completed.

Finished Product
After the ingot leaves the furnace, it is transferred to the rolling mill to be rolled into strip and then finished coils.

Ingot Transferred to Rolling Mill	Rolling Mill Presses Ingot into Strip	Finished aluminum coils

12/12/05 Removed author reference