February 2010: VibraRod™ Vibratory
Bin Level Sensor
VibraRod™ Level
Indicator Now With A
Universal Power Supply
Monitor Technologies’ VibraRod™ vibratory
type bin / silo sensor is a very reliable point level
indicator that can be used in a wide variety of applications
within the powder and bulk solids markets. Monitor’s
VibraRod unit is ideal as a high level indicator for
bulk solids as low as 3.12 lbs/ft3 (0.05 kg/dm3)
with a maximum particle size of 3/8 inches (9.5 mm).
The ordinary location VibraRod™ point
level sensor now has a universal power supply (20-255V
AC/DC). “This allows customers with various power
supply requirements to specify a single part number
for all of their different voltage requirements,” says
Greg DeRudder, Product Manager for Monitor Technologies. The
VibraRod also has many other useful features such as
a single-element probe design, requires no calibration
and a choice of probe configurations. The single-element
probe design helps eliminate false signals that typically
exist when material builds up between the tines of “tuning
fork” style probes. Also, the vibrating
action of the VibraRod tends to self-clean the probe
for most materials.
The standard length of the inserted
portion of the probe for the VibraRod™ is approximately
8 inches (203 mm). Pipe and cable extension units
are also available for longer lengths in top mounted
applications. The pipe extension unit uses 1” stainless
steel pipe to extend the vibrating sensor into the
vessel, provides structural strength, and affords a
means to secure the assembly to the vessel. The
cable extension is a polyethylene coated steel cable.
For more information, please visit www.monitortech.com
or call 1-800-601-5953 / 1-630-365-9403.
Monitor Technologies LLC, located
in Elburn, Illinois, is a leading manufacturer of level
measurement instrumentation, solids flow indicators,
particle emission monitors and aeration devices for
the worldwide powder and bulk solids markets. The experience
and market knowledge gained over 50 years of business
has earned Monitor a reputation for providing high
quality and reliable product solutions backed with
trusted customer service. For more information please
visit www.monitortech.com.
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,
etc.
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
level indication.
Principle of Operation for the TrueCap RF Capacitance Level
Probe:
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.