Application Guidelines and Properties

1. High Temperature Ceramic Fiber heaters are designed for radiant heat transfer only. They are not intended for contact heating. They do not have the physical strength found in band, cartridge, strip or cast-in heaters.

2. Mounting methods such as washers, pins, screws, overlapping edge clamps, and interlocking edges work well with Ceramic Fiber heaters. Cementing is not recommended because it will not allow expansion or contraction.

3. Ceramic Fiber Heaters have a very high porosity factor and cannot be sealed against contamination and possible damage to the heating element. Keep the furnace free of contaminants that can vaporize at high temperatures.

4. Use temperature controllers with low mass thermocouples that respond rapidly. Position your low mass thermocouple close to the element such that the element chamber Delta T can be minimized and thereby promote longer element life.

5. Thermocouples should be mounted directly above the element to closely monitor the heater face temperature.

6. Be careful with any electrical connections made in the heated portion of the application. The connections must be rated for the expected operating temperature and current flow.

7. Use only inorganic fibers and binders to avoid corrosive fumes that could damage the heater.

8. Ceramic Fiber Heaters are easily damaged from careless mechanical handling, so handle the units and leads carefully.

Typical Full Round High Temperature Ceramic Fiber Heater
5.5" I.D. by 12" H by 11" O.D.

The performance data represented in the chart was obtained by combining a Fiber Insulated Heater with 3" disks of insulation top and bottom. This assembly, which can be representative of many industrial and laboratory heating applications, was cycled with no load. Cool down rates were determined by turning the power off. Assembly was left intact. The "outside wall" temperature was measured on the external surface of the sidewall.

Performance of a Typical Rectangular Furnace

Test chamber left and right walls fabricated from Standard Fiber Insulated Heaters (24" by 36" by 5") and insulation boards. This size chamber, approximately 10 cubic feet, was chosen to best reflect performance characteristics of flat panel heaters as used in a broad section of industrial applications. Chamber walls, roof and floor are 5" thick insulation. Cool down rate was plotted with data generated after element power was turned off. Chamber door remained closed. Chamber contained no load.

Composition of Insulation

Al₂O₃ (Alumina) .........................38%

SiO₂ (Silica) ..................................62%

Organics....................................... 0%

Bond ............................................Silica

Bulk Density gm/cm³, (pcf)........ 0.28 (18)

Thermal Conductivity
W/m°K (Btu/hr°F ft²/in)

400°C (752°F) .....................................0.10 (0.8)

1100°C (2012°F) .................................0.22 (1.5)

Flexural Strength MPa (Psi)

As received ......................................0.17 (26)

After 24 hrs. at 1000°C ...............0.354 (53.6)

Compressive Strength MPa (Psi)

10% Deflection .............................0.054 (8.1)

Stability-- Linear Shrinkage

24 hrs. at temperature

800°C (1472°F)....................................0.3%

1000°C (1832°F)................................. 1.8%

1200°C (2192°F) .................................2.5%