Challenges Sensing Lightweight Polystyrene Flake Regrind in a
Blending Hopper
PROBLEM:
A South Chicago Heights, IL manufacturer of portion packaging,
primarily for dairy creamers, has had much difficulty sensing the
high level in their blending hopper. The hopper contains polystyrene
flake regrind that is very lightweight. They have not had success
using proximity switches due to the low dielectric constant of the
material and dust build-up. What can be used for point level monitoring
with very light materials and in an environment where some dust also
exists?
EXPLANATION:
Materials too light for rotary paddle units (paddle
may just turn and carve a hole in the material) and too light and
dusty for proximity switches are usually problematic. Even capacitance
probes with high sensitivity, such as the TrueCap® family from
Monitor Technologies, may not be successful. Lightweight materials
usually have very low dielectric constants, close to that of air,
making sensing by RF capacitance methods difficult if not impractical.
What will work on lightweight materials less than 5 or even 3lbs/ft³?
SOLUTION:
Many plastic processors have this problem. Those that work
with very lightweight materials, even dust, and any “flake” or “regrind” definitely
can have this challenge. However, vibratory point level sensors
with a single probe design (not tuning forks) tend to work very
well
in these applications, unless there is the possibility of very
heavy
build-ups but this isn’t very likely with very light materials.
In this example the customer solved their problem of sensing polystyrene
flake regrind by using the Model PZP vibratory point level sensor
from Monitor Technologies.
The Model PZP uses state-of-the-art piezoelectric and electronic
technologies to provide the ability to sense materials as light
as 1.5lbs/ft³. The PZP also provides a relay output and is equipped
with a universal power supply for AC or DC operation.
The PZP is a proven problem solver even for difficult challenges
like very lightweight materials. The PZP is available in a wide
range of probe configurations.
Give Monitor Technologies a call
and let us put our creative solutions to work for you!
SiloPatrol® SE Measuring coal powder levels when nothing else will work ….
Coal-fired power plants are commonplace around the
world. In order for these power generating stations to create
huge amounts of electricity the turbines need to be feed with steam
and the steam created by boilers that are fired by … yep,
coal. But coal as it comes from the mining operations is not
what is fed to the burners. First it is ground or pulverized
into powder. It is not unusual for the coal powder to be stored
in silos awaiting the demand for it to be fed to the burners. The
inventory of coal powder in these silos needs to be monitored to
allow for efficient operation of the power plant.
So, how do we monitor the inventory of coal powder in a silo? Not
easily. In one typical application the power plant personnel
found that the only technology that would work reliably is the modern
smart weight & cable system from Monitor Technologies LLC, the
SiloPatrol® SE.
Anhui Tongling power plant in Anhui province in China had tried
almost ever technology possible to get a reliable level measurement
in their 5 coal powder silos. Radar, ultrasonic and others
were tried, but none worked reliably. It wasn’t until
Beijing Conasen walked in and proposed that the Tongling plant use
the SiloPatrol SE smart cable-based inventory monitoring system that
the power plant personnel found a reliable solution.
Mr. William Yuan, sales manager for Beijing Conasen indicates that
the power plant tried many major brands of ultrasonic, radar, and
other technologies but that due to good relations with the Tongling
plant personnel he was able to sell three SiloPatrol SE model SMU
sensors and an HMI operator interface to them. The units were
installed by plant personnel. Because of the heavy amount of
coal dust in the silos an air purge using dry compressed air was
used. The SiloPatrol sensor incorporates the patent-pending
use of Hall-effect sensor technology, a split-compartment enclosure,
microcontroller, redundant optics and many other valuable features
and technology to ensure reliable measurement even in challenging
dust applications like coal powder.
The SiloPatrol SE system has been working reliably and the plant
has since purchased two additional sensors and connected them into
the same HMI operator interface. This same sensor technology
is working reliably at other coal-fired power stations in China as
well.
For more information on the SiloPatrol SE click
here or contact Monitor Technologies LLC at 800-766-6486 in
the USA and 630-365-9403 worldwide.
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