Content:
Ceramic cartridge elements
Other ceramic elements
Quartz tube heaters
Bead insulated coils
String elements
The wire, normally in coil form, is situated on the surface, in a groove or a hole of the electrical insulating material.
Generally Kanthal® AE, Kanthal® AF and Nikrothal® 80 are the most suitable materials.
In order to avoid deformations on horizontal coils, the wire temperature should not exceed the values given in the diagram on this page.
CERAMIC CARTRIDGE ELEMENTS
Characteristics
Most common design consists of round ceramic bodies with longitudinal holes or grooves for heating coils. Elements are often in metallic tubes with terminals at one end. Often provisions are made to avoid excessive sagging of the coil when the element is operating vertically.
Recommended alloys
Kanthal® A or Kanthal® D for horizontally operating coils.
Nikrothal® 80 (usually) for long vertically situated coils when sagging is a problem.
Surface load
Wire: 3–6 W/cm2 (20–40 W/in2).
Element: 2–5 W/cm2 (19–39 W/in2).
Typical applications
Liquid heating, storage heaters.
Other ceramic elements
Characteristics
Coiled and straight wire is located on smooth ceramic tube or in grooves or holes of ceramic bodies of various shapes (plates, tubes, rods, cylinders, etc.).
Recommended alloys
Kanthal® A, Kanthal® AF and Kanthal® D.
Nikrothal® 80 (for pencil bars).
Surface load
Wire: 3–9 W/cm2
(19–58 W/in2).
Typical applications
Boiling plates, air guns, hobby kilns, radiators.
Quartz tube heaters
Characteristics
Heating coil or porcupine shaped wire is placed inside quartz tube (or tube of glass ceramic). When the element is operating vertically or at an angle, the coil should be tight-wound and pre-oxidized. For horizontal use, the relative pitch is 1.2–2.0.
Recommended alloys
Kanthal® AF and Kanthal® AE.
Surface load
Wire: 2–8 W/cm2 (13–52 W/in2).
Element: 4–8 W/cm2 (26–52 W/in2).
Typical applications
Space heating, infrared heaters, toasters, toaster ovens, grills, industrial infrared dryers etc.
Bead insulated coils
Characteristics
Heating coils are insulated by ceramic beads. With beads having two holes, heating mats are made.
Recommended alloys
Kanthal® D.
Nikrothal® 80 (for panel heaters).
Surface load
Wire: 1–8 W/cm2 (6–52 W/in2).
Typical applications
Mats for in-situ annealing of welded parts, panel heaters, waffle irons, domestic ovens, water heaters.
String elements
Characteristics
Heating wire wound on insulated steel wire (approx. 2 mm (0.079 in)) or fiberglass cord.
Recommended alloys
Kanthal® D.
Surface load
Wire: <10 W/cm2.
Typical applications
Stationary hair dryers.
