Crushable insulators are available in Alundum® 99.8% fused Al2O3 and Magnorite® 99.5% fused MgO grades.
Insulators are ‘threaded’ on thermocouple conductor wires and inserted inside a seamless metal tubing. The entire assembly is then swaged or drawn down to desired dimensions.
During swaging the insulators crush readily into a powder, compacted around the thermocouple wires, providing electrical insulation resistance.
Outer diameters between 0.5 mm and 12.7 mm are available, with hole diameters in the range of 0.18 mm to 1.75 mm.
The number of holes in an insulator can range from 1 to 6.
Insulator lengths are available in 25.4 mm increments up to 101.6 mm maximum.
ALUNDUM® (fused Al2O3) Crushable Insulators AN 900
| Typical | Minimum or Maximum | |
| Al2O3 | 99.85% | 99.65% Min |
| Fe2O3 | 0.06% | 0.10% Max |
| SIO2 | 0.02% | 0.08% Max |
| CaO | 0.02% | 0.08% Max |
| MgO | 0.02% | 0.08% Max |
| ZrO2 | 0.0001% | 0.08% Max |
| Na2O | 0.02% | 0.06% Max |
| C | 0.004 - 0.01% | 0.01% Max |
| S | 0.03% | 0.005% Max |
| Cd | None Detected | 0.001% Max |
| B | None Detected | 0.001% Max |
* Technical data, right of modification reserved.
MAGNORITE® (fused MgO) Crushable Insulators MN 399A
| Typical | Minimum or Maximum | |
| MgO | 99.48% | 99.40% Max |
| SiO2 | 0.10% | 0.13% Max |
| Al2O3 | 0.08% | 0.15% Max |
| CaO | 0.24% | 0.035% Max |
| Fe2O3 | 0.10% | 0.015% Max |
| C | 0.01% | 0.02% Max |
| S | 0.001% | 0.0025% Max |
| Cd | 0.001% | 0.005% Max |
| B | None Detected | 0.001% Max |
* Technical data, right of modification reserved.
STANDARD MANUFACTURING CAPABILITIES & TOLERANCES
* Technical data, right of modification reserved
| From | To | Tolerance (mm) |
| 0.5mm | 1.4mm |
+ 0.050mm - 0.025mm |
| 1.4mm | 2.3mm | 3 0.050mm |
| 2.3mm | 3.2mm |
+ 0.080mm - 0.050mm |
| 3.2mm | 6.3mm | 3 0.080mm |
| 6.3mm | 9.5mm | 3 0.100mm |
| 9.5mm | 12.7mm |
3 0.0150mm |
| 0.18mm | 0.41mm |
+ 0.050mm - 0.025mm |
| 0.43mm | 1.73mm |
3 0.050mm |
| 1.75mm | 7.24mm | 3 0.080mm |
