Sensor Used for Material Presence/Absence
Detection in Tight Spaces
Monitoring material presence
and absence in small bins, tanks and hoppers can
often be challenging when the space is limited and
the vessel size very small. For this reason
Monitor Technologies is please to introduce its AC
and DC Capacitive Proximity Switches. These
units are 30mm in diameter and easily mount in all
types of metallic vessels and can be used to monitor
the level or material absence and presence of a wide
variety of materials. These compact sensors
are designed specifically for non-hazardous areas
and compact spaces.
Monitor Technologies LLC is a leading supplier of level, flow, particle emission
and aeration instrumentation for the worldwide powder and bulk solids market.
The experience and market knowledge gained over five decades has earned Monitor
a reputation for providing high quality and reliable product solutions. Monitor
is located in Elburn Illinois, give us a call today and let us put our creative
solutions to work for you!
For more information refer to www.monitortech.com or contact us at 800-766-6486
The TrueCap® Model MK-2
RF Capacitance point level probe is designed to provide a superior
and stable sensitivity threshold making it suitable for a variety
of powder / bulk solids and some liquid or slurry applications.
Advanced features of the Model MK-2 include: > Automatic immunity to material build-up on
the probe by its driven shield design > Push-button calibration > Enhanced temperature compensation > Maximized reliability via smart sensing algorithms
like “self-validating” fail-safe protection > Visible status LED on ordinary location units > Versatility through a variety of configuration
options including: hazardous location version, split architecture
design, quick-connect process connection, stub probe, cable extensions,
solid extensions, Nylon® probes, Ryton® - equiv. probes,
A practical application for the TrueCap would be to use this level sensor where
a residual material build-up on a different sensor would cause a false material
Principle of Operation for the TrueCap RF Capacitance Level
The vessel wall and the active probe element establish an impedance reference
between each other when exposed to air which has a dielectric constant of 1.
When materials with a dielectric constant greater than 1 are in close proximity
to the probe, the impedance of the sensing field between the sensor and the vessel
wall will change. Once the amount of change exceeds a threshold that was electronically
determined during the calibration process, an output relay will either be energized
or de-energized depending upon the position of the fail-safe selector on the
probe’s electronic circuit board. A change of as little as .5 pico-farad
is all that is necessary for the probe to sense the presence of material.