Channel Furnaces

The heart of a channel furnace is the inductor and it must be extremely reliable and predictable. This is why Ajax Tocco places a great deal of emphasis on inductor design. Iron Melting Copper Based Alloys Ajax developed most of the designs that are used throughout the industry today. The premier designs are the patented Ajax Uni-Directional-Flow and high power Jet-Flow inductors. They are unquestionably the most reliable and most technically advanced in use today. In the Jet-Flow inductor, metal flows downward into the entrance of the center channel and divides evenly into the bottom channel and flows in jet-like streams upward and out continuously from both outer channels. The temperature rises accordingly as the metal progresses along this path. Movement flows at the rate of up to 700 tons per hour. Because of this, the temperature between the furnace bath and the inductor channels is very low. Metal velocity is precisely controlled and prevents hot spots and allows the maximum available power to be applied to the furnace all day if needed without damaging the inductor. It is, in fact, this technology which allowed Ajax to build 6000 KW inductors – the highest in the industry. As the world leader in channel furnace technology, Ajax TOCCO continues to refine the design of the famous Jet-Flow inductor. Ajax TOCCO has not only broken the 6000 kW barrier, but can also point to the successful start up of the largest channel furnaces in the world. AJAX TOCCO MAGNETHERMIC air-cooled model TE Jet-Flow electric inductors are available up to 500 kW. Each inductor is air cooled by integral blowers. The inductor is supplied as a complete unit and complete interchange ability between inductors is assured. Each Jet-Flow inductor comprises the following: (1) Inductor case of welded heavy steel construction flanged to match the furnace shell and fitted with suspension brackets (1) Furnace transformer assembly (2) Cooling air blowers each with integral driving motors (2) Split copper air duct-bushing Ajax TOCCO systems provide the most advanced state of the art heating equipment. These systems offer the shortest heating lengths and the most efficient system in the industry. We continue to develop new ways to improve the system to satisfy our customer’s needs.
Metal Velocity and Temperature Rise
Temperature rise is the temperature differential between the main or upper part of the furnace and deep within the channels of the inductor. This phenomenon has a most profound effect on channel furnace operating characteristics. When power is applied to the inductor, temperature rises in the main bath and the temperature in the channel rises above the bath temperature. This difference can be as much as 500°F with traditional single loop and other inductor designs.   The above chart compares the difference between the temperatures in the channel with that at the bath temperatures at various KW ratings.	With the Ajax TOCCO jet-Flow inductor, this temperature rise is less than 70°F even for the highest rated inductor. As a result, Jet-Flow inductors are not subjected to extreme thermal cycling. The temperature in the channels remains relatively constant and results in significantly increased refractory life. For example, in a 1500 KW Jet-Flow inductor operating at full power, metal uniformly flows in a jet-like action at the rate of 380 tons per hour and stirring in the upper bath becomes more pronounced. Because of this increased stirring, metal chemistry is more homogeneous. Another factor affecting temperature rise is the speed at which molten metal flows in the channels. The stirring also lowers metal additive losses and increases refractory life. Overall, it provides for more efficient melting and improved metal quality.