Measuring Material Level in Dusty Talc Applications for Luzenac
“Ultrasonic systems from two leading manufacturers don’t
work because of the heavy dust. The older weight and cable style
doesn’t work well because of high maintenance. I need a reliable
Luzenac supplies the pulp, paper and board industry with talc for
use as a pitch control agent and a runnability aid, a coating pigment
in both rotogravure and offset, and a functional filler. In certain
specialty papers, e.g. colored papers, labels, Luzenac talc’s
special properties help to improve quality and productivity. Talc
also has application as an additive to ceramic, rubber, plastics
and even roofing materials. Talc is about 50lbs/ft³ and very dusty.
Older electromechanical weight & cable devices couldn’t
live up to the rigors of the application, neither could ultrasonic
systems that were blinded by the heavy dust.
The Monitor Technologies SiloPatrol® smart cable-based sensor
system with 4-20mA output was being used successfully on this difficult
application at the Luzenac plant in Sappington, Montana. The Three
Forks plant needed a solution and decided to try the SiloPatrol inventory
monitoring system to reliably keep track of their finished goods
inventory. In this tough application the SiloPatrol proved to be
the best solution. The sensor is unaffected by the dust and internal
bin structures. The SiloPatrol sensor uses a powerful direct drive
motor and 270lb. tensile strength cable along with state-of-the-art
microcontroller based electronics.
Luzenac prefers the SiloPatrol
system to other equipment they have tried. This is evidenced by
their usage at the two plants in Montana
and one plant in Houston, TX. They have dozens of units in place
that continue to work reliably for them.
Give Monitor Technologies a call and let us put
our creative solutions to work for you!
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.