Ceramicomb Dielectric Sensor

Figure 1.
Ceramicomb-1” reusable dielectric sensor
(rear exit version shown)


The Ceramicomb-1” is designed for use in presses, molds or harsh environments where a rugged, reusable dielectric sensor is desired. It may be mounted so the electrodes are flush with a platen or mold surface, insuring no interference with the flow of material during processing. The sensor is constructed with silver-palladium electrodes embedded in an alumina substrate, protected by a stainless steel sheath with a nominal 1.0” (2.54 cm) diameter. A thermocouple is positioned in the ceramic just below the surface to allow measurement of process temperatures. Dielectric and thermocouple signals are routed through a 10-foot (3 m) long stainless steel conduit to high temperature connectors. Sensor and cabling are rated for operation up to 250 degrees C and are suitable for R&D, QA/QC and manufacturing applications with repetitive operations.


Dimensions (available with side or rear exit conduit):
Diameter, sensor head : 1.0” (2.54 cm) nominal
Height, sensor head : 1.0” (2.54 cm) nominal
Length, conduit : 10’ (3 m) nominal

Diameter, active face : 0.69” (1.75 cm)
Width, electrode : 0.020” (0.5 mm)
Spacing, electrode : 0.020” (0.5 mm)

Ceramic : Alumina
Electrodes : Silver-palladium
Sheath/conduit : Stainless steel
Cabling : Teflon

Temperature, maximum : 250 Degrees C (480 Degrees F)
Frequency, mid-con mode : 0.1 Hz – 100 KHz
Frequency, high-con mode : 0.001 Hz – 100 KHz

Sensor Parameters:
A/D ratio : 10 cm
Base capacitance : ~20 pF – 25 pF (actual value may vary)

Thermocouple: Type J standard,
Type K available upon request

Measurement, mid-con mode:
Log Conductivity : -13 to -4 Log(siemens/cm)
Log Ion Viscosity : 1 to 13 Log(ohm-cm)
Log Loss Factor : -1 to 4
Permittivity : 1 to 102
(Not recommended for accurate measurement
of permittivity, although trends are indicative)

Measurement, high-con mode:
Log Conductivity : -10 to -1 Log(siemens/cm)
Log Ion Viscosity : 1 to 10 Log(ohm-cm)
Log Loss Factor : 1 to 6
Permittivity : Not applicable