Equipment Details

ITM – Isothermal Melting Furnace

The Isothermal Melting Furnace (ITM) comprises five interconnected zones: pumping for recirculation, charging, melting, metal treatment and holding. The process is a closed loop with molten metal recirculating through each zone. Solid charge is added continuously in any form including ingot, scrap castings, gates and risers, trim and flowable scrap such as chips (turnings and borings).

Melting heat is introduced from an array of immersed elements corresponding to the energy required by the charging rate. The molten stream is treated for the removal of dissolved hydrogen and entrained nonmetallics, and supplemental heating for holding temperature in the system is provided by resistance elements embedded in refractory wall panels of the holding section. 

Therefore this technology allows melting energy to approach the theoretical limits.


  • Drastic reduction of oxide formation, reduced skim frequency, more product/less waste 
  • Increased productivity and lower operational cost due to the longer refractory lifetime and efficiency
  • Melting Power directly proportional to melt rate
  • Predictability, Controllability, Stability
  • Thermal mass provides stability
  • Heaters operate at a very high flux, and require a comparatively small portion of the overall ITM footprint
  • Eliminates risk of contamination, reduces installation and start-up time
  • Safety measure assuring Metal containment and low steel shell temperatures
  • Abundant cleaning and sampling access without interrupting electrical power and the operator is not exposed to surfaces significantly elevated above metal temperature


  • Metallophobic Silicon Carbide Containment Refractory
  • Continuous Circulation Loop
  • Dual Method Heating System
  • Containment heating system uses cartridge type electric resistance heaters contained within heat transfer tubes
  • Direct Immersion (DI) heating, is used for melting
  • Heat application  is direct and exclusively sub-surface
  • Pre-cast, kiln fired, refractory
  • Microporous insulation
  • No Electrical / Gas connections to the lid
  • Protected by the following U.S. Patents: 5,963,580; 5,968,223; 6,066,289; 6,444,165; 6,470,041; 7,033,538; others pending


  • Melting Energy Approaches Theoretical Limits
  • Low Holding Energy Consumption
  • Sub-surface Conduction Heating
  • Cool Lid & Wall Temperatures
  • Superior Refractory Life
  • Low Maintenance Down Time
  • Isothermal Holding Capabilities to 1450°F


  • Superior Refractory Life while maximizing internal heat conduction
  • Melt on Demand Process
  • Hold with moderate watt density, Melt with high watt density
  • Protected by sidewall of the working lining
  • DI heaters also convert all of the supplied electrical energy to heat and transfer essentially all heat produced to the melt
  • No oxygen present at heat source
  • Consistent, repeatable, tightly controlled refractory pour
  • Freeze plane containment inside vessel wall, minimizes heat transfer to the environment
  • Lids are light weight and easily removed by hand without counterweights or pneumatic assist


MODEL 800 5000
MAX. PRODUCTION 800 lb/h 363 kg/h 5000 lb/h 2268 kg/h
HOLDING MASS 10,000 lb 4536 kg 26,000 lb 11793 t/h
REQ. MELTING POWER 464 kBTU/h 135 kW 2900 kBTU/h 842 kW
MAX. INPUT (Melting only) 537 kBTU/h 156 kW 3300 kBTU/h 960 kW
REQ. HOLDING POWER 140 kBTU/h 41 kW 310 kBTU/h 90 kW
MAX. INPUT (Holding only) 345 kBTU/h 100 kW 620 kBTU/h 180 kW
IMPELLER 12" 305 mm 20" 508 mm
RECIRCULATION 225 klb/h 102 t/h 800 klb/h 363 t/h
CHARGE WELL 24" 610 mm 36" 914 mm
Updated date: 05/26/2016