In many cases, metal is transferred from melting/holding furnaces to pouring stations by ladle. Apogee’s Transportable Electric Ladle (TEL) (Fig. 5 and 6) is basically a shell contained refractory crucible comprised of BSPP heating elements. TEL can be used to hold metal as an alternative to conventional holding furnaces, to transport metal in-plant or to deliver molten metal over unconstrained distances at controlled temperatures. Over the road performance includes maintenance of composition and molten metal quality in comparison with existing unheated ladles which rely on extensive high temperature preheating and super-heated metal for successful delivery. TEL includes heating, temperature maintenance and controls and a Department of Transportation approved design. As in other BSPP applications, energy efficiency is excellent. A 22,000 pound capacity TEL consumes 86,500 BTU/hr vs. an estimated preheating input of 2-3 million BTU, for an unheated transfer ladle which after charging loses 0.75F/minute. Demonstrated TEL temperature control is +/-5F.
In the advanced concept, TEL is used as a highly efficient alternative to conventional holding furnaces. Capacities can be consistent with operating requirements and holding energy is only 3.9 BTU/lb compared with an existing energy benchmark for gas fired holders of 44 BTU/lb.
Finally, most ladles are emptied by either cascade or tap hole. In the latter case, metallostatic heads of 7 – 10 feet result in uncontrolled initially high velocity, then variably turbulent flow. TEL can be equipped with a controlled negative pressure which dispenses metal without turbulence at controlled rates. The system is called Power Modulated Dispensation (PMD).