Dumbell Shaped Silicon Carbide Heating Elements
The Dumbell Shaped SIC Heating Elements are one of the earliest heating designs. The cold ends of the Dumbbell SiC element were enlarged to increase the cold end cross-section. This lowered the electrical resistance, thereby reducing the cold end operating temperatures. Due to the advancement of technology, there is no longer the need for oversized cold ends by keeping the terminal ends cool by decreasing the resistivity of the lower resistance cold end material. Silcarb manufactures Dumbbell Shaped SiC Elements whose cold zone to hot zone resistance ratio is 1:15.
The first few inches of the cold ends are metalized with aluminum to provide a low resistance contact surface. The electrical connections are made at the cold end with flat aluminum braids. These braids are held in compression onto the cold end with the help of stainless-steel spring clamps. A high density of the material used (2.4gm/cc) helps the heating element prevent oxidization and results in slow aging.
The Dumbbell Shaped Heating Elements can operate to furnace temperatures up to 1500° C (2730° F). If the furnace temperature is 1425° C or above, the cold ends must be well protected within the refractory wall of the furnace so that there is no damage caused to the furnace. Silcarb Dumbbell Shaped Heating elements gradually increase in resistance with use. This characteristic is also known as aging. The aging depends on several factors like operating temperature, atmosphere, maintenance techniques, etc.
Dumbell Shaped SIC elements can be mounted in any orientation. To ensure that there is no physical binding of the heating elements, suitable holes through refractory walls or in ceramic lead-in sleeves are made. The alignment of the support holes through refractory walls should also ensure that no physical binding occurs.
The Dumbbell Shaped SiC Heating elements are available in different product forms and can be customized to different standard sizes and geometries to suit a variety of heating processes. Contact us for any further details.
Oversize, cold ends are therefore no longer necessary, the old-style resistance ratio was 1:3, whereas the new DB resistance ratio is 1:40. The maximum temperature is 1550o C. (For Dimensions, Resistance, etc. kindly contact us):
For further information on silicon carbide heating elements…
Download Silcarb SiC Heating Elements Brochure
Download Silicon Carbide Heating Elements Technical Brochure