Thermcraft Technical Articles
Thermcraft CoilCraft Element System (CCES)Convserion
In mid 2006, Perryman Company (a Western PA metals producer) issued an order to Thermcraft Inc to produce a series of drying ovens for processing metal scraps as part of a proprietary process developed by Perryman. Based on the specifications developed during the initial discussions, Thermcraft supplied units that employed its standard PH-C series heavy-duty cast plate heaters mounted under the client supplied process unit.
The units worked quite satisfactorily for a couple of years. At that time, Perryman added process air to assist in removal of volatiles given off during processing. The process air added an additional loading factor to the heaters and contributed to metals fines contaminating the heater compartment. Both issues contributed to heater failure at both ends of the chamber where contamination was the greatest. A new set of replacement heaters was installed but the end heaters failed again in approximately six months. A second set of heaters suffered a similar fate. Since the top of the furnace and the rotating drum had to be removed to enable heater replacement, a considerable amount of expense and downtime was involved in addition to the cost of replacement heaters.
At this point, Perryman called Thermcraft to discuss possible solutions to this problem. As part of these discussions, the following series of requirements for potential solutions were developed:
- The new heater system had to be designed so replacement of failed elements would not entail disassembly of the furnace.
- It proved highly desirable not to modify the existing power supply for the furnace.
- Provisions had to be incorporated to protect elements from product contamination
- The conversion had to involve a minimum of production downtime.
- Above all, the conversion had to be cost effective.
After reviewing several options, it was decided that Thermcraft’s CoilCraft Element System (CCES) was the most practical option to solve the above problems. This system is essentially a heavy gauge wire element combined with a ceramic support structure. For this particular application, leads were designed so that both would exit the same side element end, allowing for insertion or removal of each indivi
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