Product Spotlight
Direct Electric Heat Induction Furnace for Aluminum
by Ed Chmielecki, Sales Manager, Light Metals Applications, Inductotherm Corp. T
raditional aluminum melt furnaces,
including Electric Resistance (ER), induction and
fossil fuel-fired furnaces continue to be options for melting aluminum. Inductotherm Corp., Rancocas, NJ, is offering a new method for melting aluminum and other nonferrous metals that,
in many applications,
will melt metal more efficiently, quickly and cleanly. The Acutrak® furnace with Direct Electric Heat (DEH) technology is well suited for investment casting applications. Prior to the introduction of this new furnace, aluminum casting facilities relied on inefficient and costly ER and fuel-fired crucible furnaces or refractory-lined reverb furnaces to melt and hold aluminum for their castings. In traditional induction furnaces, the magnetic field couples to the metal inside and the metal itself gets heated. In an Acutrak®
DEH
furnace system, the crucible conducts the electric current, becoming a resistive load for the system. Acutrak®
is a revolutionary induction melting furnace –
the first in the industry to utilize an air-cooled coil. The total energy efficiency for the furnace is very high at 92-94%, which according to the company has never been achieved before by any other electric or gas-fired furnace. The system can transfer 94 kW out of 100 kW, which has been withdrawn from the utility line and is applied to the crucible for metal melt. The DEH technology utilizes a silicon carbide crucible,
which provides faster, cleaner and more efficient melting. Combined with the Acutrak®
electrical energy directly into the crucible. The metal is heated evenly and to a precise, preset selectable temperature with minimal overshoot by way of an immersion metal bath thermocouple, which is coupled to a digital temperature controller.
furnace, it is able to apply
minimized. This reduces the disruption of the protective oxide layer on the surface of the molten bath and prevents contact of high temperature aluminum with oxygen. Thus, inclusion and dross formation, which is a result of oxidation, is greatly reduced along with metal loss. Acutrak®
uses a special patented furnace coil coupled
with the high resistance of the silicon carbide crucible. By comparison, traditional ER furnaces that use fragile element panels cause a loss of production when elements fail. Due to the reduction of the melt rate, the kW rating of a traditional ER furnace drops with each panel failure. This decrease creates a “domino effect” making the functioning elements work harder to compensate for the failed panels. A complete shutdown of the furnace will need to be scheduled for replacement of the expensive element panels—compounding the production loss. Another by-product of this scenario is the reduction of crucible life from the “cold spots” caused by element panel failure. The patented furnace coil on the Acutrak®
furnace This clean induction technology provides
exceptional metal recovery and quality at the required casting temperature for their process. Due to the fact that 95% of the power is concentrated in the crucible, the electromagnetic forces formed in the liquid metal are very low; therefore, the stirring effect is also
24 ❘ May 2020 ®
ensures excellent transfer of energy into the crucible, avoiding production loss. The furnace provides precise temperature control via two thermocouples placed inside and outside the crucible. Since temperature control is achieved as only the crucible and the metal are heated, there is no stored excessive energy retained
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