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Thermix offers a range of high capacity Aluminum melting furnaces with sizes up to 200,000 lbs (91 tonnes). These furnaces are static gravity discharge furnaces and can be adapted to pump well or direct launder discharge. These furnaces are of rugged construction with durable operating
linings, featuring hydraulic actuation of the door and door seals that allow for quick change of door for easy maintenance.
Bath temperature control is accomplished via thermal head control (THC). As metal temperature approaches the required set point control is transferred from the heating chamber to a bath thermocouple. Careful selection of the appropriate transition temperature dramatically reduces melt temperature overshoot and ensures good efficiency.
Fuel and air ratios are controlled electronically via a standard PLC package. The PLC calculation uses gas and air flow rates which are measured by dedicated transmitters.
The furnace is fitted with a specially designed recuperator with large external gas passages for easy cleaning and long service life in this application. The recuperator is capable of operation up to 1000°C and will provide preheated combustion air up to 500°C. The combustion system achieves an efficiency in the range between 62.5% - 75%.
Depending on the charge rates, Thermix furnaces fitted with recuperator are operating at 1050 - 1250 Btu/lb during melting.
Furnace pressure is controlled by regulation of the flow rate of eduction air at the flue. The eductor draws sufficient pressure to overcome losses through the heat exchanger and ducting. A pressure transmitter provides a signal which enables the operator to select any value between -0.5”W.C. and +0.5”W.C. and achieve control which is within ±0.02”W.C. All this is achieved without a flue damper.
The furnace is fitted with a positive pressure seal to limit the flow of air into the furnace. Control of air ingress limits the potential metal loss due to oxidation.
We are able to offer a well design specifically tailored to chopped material utilizing a pump-through well design with an overhead charge chute and well vortex generator. In operation, the material entering the furnace is immediately submerged. Melting material is thus prevented from contact with air. This in turn minimizes oxidation losses.
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