Lambient

Single Electrode Dielectric Sensors

Single Electrode Dielectric Sensor

Figure 1
Single Electrode Dielectric Sensor

8-mm diameeter unsheathed (left) / 0.5-inch diameter sheathed (right)
Single electrode reusable dielectric sensors
(Rear exit versions shown)


DESCRIPTION

Suitable for R&D, QA/QC and manufacturing applications with repetitive operations, the 8-mm dia. unsheathed and 0.5-inch dia. sheathed single electrode sensors are designed for use in presses, molds or harsh environments where a tiny, reusable dielectric sensor is desired. They may be mounted so the electrode is flush with a platen or mold surface, insuring no interference with the flow of material during processing. These sensors are constructed with a stainless steel electrode embedded in a high temperature polymer insulator. An optional thermocouple may be positioned in the sensor cable just behind the sensor head to allow approximate measurement of process temperatures.


The 8-mm sensor is rated for operation up to 200 °C, and its dielectric and thermocouple signals are routed through a 10-foot (3 m) long Viton tubing to a standard dielectric connector. The 0.5-inch sensor is rated for operation up to 250°C uses a 10- foot (3 m) long steel conduit.


The single electrode of the 8-mm and 0.5-inch sensors requires a nearby grounded metal surface for proper sensor operation. The configuration is effectively a set of parallel plate electrodes which needs correct determination of A/D ratio and base capacitance for accurate calibration. A/D ratio and base capacitance are typically measured experimentally and depend on exact mold and mounting configuration.

SPECIFICATIONS

Dimensions:
8 mm (unsheathed)                 0.5” (sheathed)
Diameter: 8.0 mm nominal 12.6mm (0.5 inch) nominal
Height: 11.0 mm nominal 14.3 mm (0.563 inch) nominal
Length, Conduit: 10' (3 m) nominal 10' (3m) nominal
Diameter, Electrode: 6.0 mm 6.0 mm
Area, electrode: 0.282cm² 0.282cm²

Composition:

Electrode: Stainless steel Stainless steel
Insulator: Vespel Vespel
Conduit: Viton Steel
Cabling: Teflon insulated Teflon insulated

Operational:
Temperature, maximum: 200 °C (392 °F) 250 °C (482 °F)

Sensor Parameters:
A/D ratio: 0.282 cm² / (mold gap) Note–A/D ratio is typically determined empirically and varies with exact mold and mounting configuration
Base capacitance: Determined empirically
Optional thermocouple:Type J standard, Type K available upon request

Measurement, mid-con mode:
Log Conductivity:Range varies with A/D ratio
Log Ion Viscosity:Range varies with A/D ratio
Log Loss Factor: Range varies with A/D ratio

Permittivity:Not recommended for accurate measurement of permittivity, although trends are indicative

Measurement, high-con mode:
Log Conductivity:Range varies with A/D ratio
Log Ion Viscosity:Range varies with A/D ratio
Log Loss Factor:Range varies with A/D ratio

Permittivity: Not applicable