Level Detection...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!
Spotlight: Inventory Control
Solids Flow Detection
Microwave solids flow detectors can
be used in a variety of applications including feed mills & grain processing,
consumer foods (cereal, sugar, cocoa, coffee), chemicals & pesticides
and more. For example, one company uses Monitor’s Model SFD-2
solids flow detector to verify the flow of feed pellets through their
various transport lines which involves a process where a horizontal
screw auger is conveying pellets over to a vertical gravity chute. The
chute then directs the pellets to a process down below. They have
carefully placed the SFD-2 so that it detects the pellets as they
fall directly across the sensor face. (See Below)
The Model SFI and SFD-2 line of solids flow detectors
from Monitor Technologies, LLC provide analog or relay outputs
to indicate the flow / no-flow condition of powder and bulk solids
materials in chutes and pneumatic conveying lines. Using
microwave Doppler radar technology these units are non-invasive
plus extremely reliable and rugged to withstand the rigors of the
installation and your process extremes. From automated systems
with pneumatic lines to gravity chutes, solids flow monitors can
help to improve process performance. They can assist in detecting
flow problems, as well as, enhance the level of automation at a
facility like turning a conveyor on or off.
For more information on Solids
Flow Detectors click here or contact Monitor Technologies LLC
at 800-766-6486 in the USA and 630-365-9403 worldwide.
PROBLEM:
SOLUTION: 
