Content:
Coils in grooved metal plates
Cartridge elements, powder filled
Heating cables and rope heaters
Mica elements
The wire in the embedded element type is completely surrounded by solid or granular insulating material.
Metal sheathed tubular elements
Kanthal® D is generally the best heating wire for tube temperatures below 700°C (1290°F), and Nikrothal® 80 or Nikrothal® TE for temperatures above.
To use Kanthal® instead of Nikrothal® gives the following advantages:
- Lower wire weight by some 20–30% at the same wire dimension.
- More uniform temperature along the element and lower maximum wire temperature. This means that the element can be charged higher for a short time – important when there is a risk of dry boiling.
- Closer tolerances of rating. Rating and temperature remains more constant since the resistivity in hot state does not change as much as for NiCr.
- Longer life at high surface loads. The element life is also easier forecasted.
- Kanthal® is easier to manufacture when high resistance per length is needed, since a thicker wire can be used.
- Less sensitive to corrosion attacks
Coils in grooved metal plates
Characteristics
Heating coil and insulating powder are pressed into grooves of a metal plate.
Recommended alloy
Kanthal® D.
Surface load
Wire: 4–20 W/cm2 (26–129 W/in2).
Typical applications
Cast iron plates, irons, warming plates, kettles, domestic ovens.
Cartridge elements, powder filled
Characteristics
Straight wire or coil is wound on a threaded ceramic body and insulated by granular insulating material (MgO) from an enveloping metal tube. Terminals are at one end of the element. Elements are compressed when high-loaded.
Recommended alloys
Nikrothal® 80 in straight wire elements.
Kanthal® D in coiled wire elements.
Surface load
On tube: 10–25 W/cm2 (65–161 W/in2) for elements with straight wire.
Other types: about 5 W/cm2 (32 W/in2).
Typical applications
Metal dies, plates, refrigerators.
Heating cables and rope heaters
Characteristics
Wire is wound on a fiberglass core and insulated by PVC or silicone rubber (higher temperatures). Fiberglass insulation permits even higher temperatures.
Straight heating cables sometimes enclosed in aluminum tube also occur.
Recommended alloys
Kanthal® D.
Nikrothal® 40 and Nikrothal® 80.
Cuprothal® 30, Cuprothal® 10 and Cuprothal® 49.
Surface load
Wire: <1 W/cm2 (<6 W/in2) on wire for PVC and silicone rubber, 2–5 W/cm2 (13–32 W/in2) for fiberglass insulation.
Typical applications
Defrosting and de-icing elements, electric blankets and pads, car seat heaters, baseboard heaters, floor heating.
Mica elements
Characteristics
Resistance ribbon or wire is wound on a mica sheet or tube and insulated by mica. Elements are often encapsulated in steel sheaths.
Recommended alloys
Kanthal® D.
Nikrothal® 80.
Surface load
Wire: 2–10 W/cm2 (13–65 W/in2).
Typical applications
Irons, ironing machines, water heaters, plastic molding dies, soldering irons.
