The selection of capacitance probes include sensors used for high and low level detection in bins and silos as well as vessels used for material storage or process manufacturing.
Capacitance sensors use capacitance - the ability of a body to hold an electrical charge - to measure dielectric permittivity. They can also be used to measure the level of solid materials.
A dielectric is a non-conducting substance, for example, an insulator: permittivity is a physical quantity that describes how an electric field affects, and is affected by a dielectric medium.
High and low level detection
According to Pacific Sensor Technologies the Procap I 3-A and II 3-A sensors from Bin Master "meet rigorous USDA, FDA and 3-A material and design standards" for sanitary food and dairy processing.
They operate by detecting the presence or absence of material in contact with the probe by sensing minute changes, as low as 0.5 pF (one picofarad (pF) is equal to one million millionth) in capacitance "caused by the difference in the dielectric constant of the material versus the air".
The products also feature "a Class II hazardous location rating and are available with a wide assortment of probes and extensions to meet a variety of processing needs," said the Australian firm.
At 6 KHz, the BinMaster capacitance probes work below the RF (radio frequency) level of 9 KHz for an "interference-free operation".
As a result, the sensors "will not interfere with two-way radios or other equipment operating in the radio spectrum".
Further, the sensors have “quick set” calibration and "fail-safe operation" including a visual LED (light-emitting diode) to indicate the sensor status.
Boosting visibility levels further, the distributor said that "accurate level detection is assured" even in dusty, sticky or clinging materials by the Pro-shield feature that compensates for material build up on the sensing probe.
In the event of a power failure, the probes "provide fail-safe protection", as well as an adjustable time delay to help prevent false readings.