Hogg
Fuel & Supply operates concrete batch plants in Ontario,
Canada. Hogg Fuel has been a quality supplier of ready mix
concrete for over thirty (30) years. They use a blend of Portland
cement and slag. The “slag” is actually GGBS or
ground granulated blastfurnace slag. GGBS is sometimes used
as an additive to concrete to provide benefits in the areas of durability,
quality, strength and finish. Typical batches include about
10-15% slag but this can vary depending on the need of their customer.
Maintenance Supervisor Bob Knarr was looking to replace the older
weight & cable units installed on their 20ft (6.1m) cement and
slag storage silos. Although the weight & cable based technology
provided accurate distance measurements, they required maintenance
several times per year. Bob and Hogg Fuel wanted a measurement
system that would be would not require maintenance, would provide
true continuous readout, provide the accuracy they require, while
retrofitting into the existing mounting portals on top of their silos.
This
plant was designed as an auxiliary plant to their main facility and
therefore was built with smaller capacity silos than their main plant. However,
this auxiliary plant has become increasingly busier in recent years.
This makes tracking the level critical as loads are required more
frequently than in the past.
Flexar has met all of their expectations and system requirements. As
with all complete systems, Hogg Fuel has a rotary paddle point level
unit top mounted with a two foot extension for indication of high
level to alert the cement delivery to shut down when the vessel is
full. As an added bonus, Flexar provides the batcher in the
control room the ability to track the progression of the fill cycle
right to its completion! The Flexar sensors were installed
in late April 2006.
Flexar is a guided wave radar continuous level sensor. Distance/level is
measured by the time-of-flight of the reflection of a microwave signal (transmitted
down the wave-guide, which is a heavy-duty 0.3” SS cable with 3.9 ton tensile
strength) off the material surface. Cement and GGBS slag both have relatively
low dielectric constants and Flexar’s direct measuring mode
was successful in providing real-time continuous updates of the material
level during filling and draw-down.
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.
This
plant was designed as an auxiliary plant to their main facility and
therefore was built with smaller capacity silos than their main plant. However,
this auxiliary plant has become increasingly busier in recent years.
This makes tracking the level critical as loads are required more
frequently than in the past. 
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