Regarding accuracy,
what difference between single shot and averaged data ?
The newest versions of the Riegl head over-sample the
data (take more than one range measurement of a single
point) to reduce measurement uncertainty. The single
shot measurement uncertainty of 16 mm (see
System Specifications) refers to the accuracy of
one, individual range measurement. The average
uncertainty of 10 mm refers to the accuracy of the
over-sampled data obtained from the Riegl head. The LCS
software subsequently average a number of "over-sampled"
range points to obtain an ultimate thickness uncertainty
of 5 mm.
How many
measurements are required to completely characterize a
converter ?
For a brand new BOF that has no skull in the mouth
(or for a ladle or EAF), the entire vessel can be
scanned in one measurement. This requires 20-30s.
However, once the BOF mouth begins to collect a skull
accumulation, multiple measurements are required at
different furnace inclinations and cart positions. These
additional measurements are necessary to "see" into the
furnace, and measure all surfaces (we can't measure
surfaces that are not in the field of view of the
instrument). Typically, 4-6 measurements are necessary,
depending on the amount of skull accumulation. Given the
time required to move the cart and change the furnace
inclination, although one individual measurement
requires 30s, all of them in combination could take 5-10
minutes.
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How do you verify
thickness accuracy ?
In
most cases, we cannot check the thickness directly.
What we do is check each individual component, to make
certain that each is functioning correctly, and is
within calibration. The individual components we check
are:
-
The range
measurement head,
-
The inclinometers on
the LCS cart,
-
The tracking system,
which measures the position and heading of the cart,
-
The furnace
inclinometer.
For
some applications, particularly ladles, we can compare
the remaining brick thickness at tear-out with the
measured thickness.
What measurement
accuracy is required for the converter tilt measurement
?
We must know the furnace tilt to within ±0.2 degrees.
Since most factory inclinometer do not provide this
degree of accuracy, one of our inclinometers must be
installed on each furnace.
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Does the converter
have to be rotated to a specific angle for accurate
measurements ?
The actual inclination of the BOF only has to be set
to an approximate position. This can be done by eye, no
console output is needed. The LCS system will measure
the BOF tilt automatically, and transmit the BOF furnace
tile to the LCS cart by radio link.
Can the LCS
instrument measure surface temperature ?
Yes, the system can be ordered with the optional
temperature measurement module, which gives a
single-color (emissivity-dependent) measurement of
surface temperature inside the vessel.
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What action is
typically taken after measuring lining thickness in the
converter ?
When we install the system, we configure several pages
of printed output that the operator can create
automatically after connecting the LCS system to the
printer. This gives general information about the
lining thickness in a number of different formats
(tabular, contour view, etc. An example of this
information is listed in the LCS brochure). The data
itself contains over one million points, so there is
more detailed information available if the manager
wishes to review the data using a remote workstation
computer.
What additional data
are needed to calculate bath level using the lining
thickness measurement results ?
The
software requires the charge weight, slag weight, steel
density, and slag density to display the bath height of
both the steel and slag.
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How many measurements
can be made before the batteries must be charged in the
furnace inclinometer ?
Assuming the system stays on for 1/2 hour during each
measurement, approximately 50 measurements. An automatic
timer shuts the inclinometer off after a preset time
period. There is a voltage readout on the battery
inclinometer enclosure that tells the operator when the
batteries must be recharged. We also provide a complete
set of spare batteries so a quick replacement can be
made without delaying the lining thickness measurement.
Where must the battery
powered inclinometer be located ?
The battery powered inclinometer can be mounted to any
piece of machinery that rotates with the converter.
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What does it mean
"batteries and associated chargers were adapted from
portable video camera technology ?
The
battery-powered inclinometer system that measures the
furnace tilt consists of the inclinometer, radio
transmitter, batteries, battery meter and tilt meter.
The batteries that power the system are a type of
battery that is used on a Sony camcorder. Therefore,
should new batteries be needed, they can be easily
obtained from an electronics store. Of course, we stock
batteries here, so we can send you some as well.
What is the form of the LCS
Software data base ?
Our data base is proprietary. You must use our
software to review the data. The data can be put on the
plant network, and viewed remotely, though our software
will have to be running on the remote computer.
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Can additional copies of the
software be installed on computers other than the one
controlling the LCS system ?
Two software licenses are provided
with the standard system. One is installed on the
system; the second can be installed on an independent PC
by the customer. Additional licensed versions of the LCS
software can be purchased for installation at multiple
locations.
Is regular calibration of the
LCS instrument required ?
During initial installation and commissioning,
Process Metrix will install a fixture that allows you to
easily check the heading and position measurement
accuracy. We recommend checking the tracking system
position indication once per month. The Riegl head
should be checked once per quarter by measuring a target
at known distance from the instrument. Process Metrix
will also provide the fixture and method for checking
the Riegl head.
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What is the service interval
for the Riegl head ?
The laser head should have routine service performed
after 3000 hours of use. To do this, the head must be
removed from the LCS cart and shipped to Austria.
Process Metrix offers an extended warranty that covers
the entire system. Should you decide to purchase the
extended warrantee (which is renewable on a year-to-year
basis), we provide an exchange laser head, and take the
old system back for service.
What is the delivery time for
LCS ?
This depends on your required level of customization,
and the status of any particular build cycle at Process
Metrix. Typical lead times are 5-8 weeks
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What is the actual
consumption of spare parts for 1 year of an LCS
'operation period ' ?
Spare parts consumption is low. For the mobile cart we
recommend the minimum spares shown below for one year of
operation:
-
Several spare
reflectors,
-
A spare inclinometer
enclosure,
-
Spare radio
antennas,
-
Computer filters,
-
Printer and
cartridges (these should be purchased locally.
Otherwise, if we purchase the printer here, you will
not be able to purchase cartridges in Russia for a
printer purchased in the United States).
What are quantitative
demands on cleanness of reflectors for navigation system
of the LCS ? How often do they have to be cleaned from
dust ?
The reflector material is the same as that used for
road signs. It is very durable, and works even when
there is dust on them. Our present customers clean the
reflectors every 2-6 weeks, depending on their location
in the plant. They can be clean easily by spraying them
with water.
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Does the mobile cart require
cooling ?
Cooling is not normally needed for the LCS mobile
cart. We only provide the option for cooling for cases
where the instrument has been left in operation on the
plant floor for several hours, and the internal
temperature has risen to high levels. In this case,
nitrogen or air can be connected to the mobile cart for
a short period to cool the system. The cooling air line
IS NOT NEEDED DURING MEASUREMENTS IN FRONT OF THE
CONVERTER.
Can the mobile cart
withstand the temperature in front of a hot converter ?
Our customers who are using the
mobile cart position the LCS cart within 3-5m of the
furnace mouth, and take between 5-6 readings that
require 4-8 minutes. These measurements are made when
the furnace is hot, typically 1400-1600
°C.
The unit has double heat shielding, with insulation
between the heat shielding. There is never a problem
with overheating of the LCS cart and cooling is not
necessary unless the cart has been left running on the
plant floor for extended periods.
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What are the conditions
to keep the LCS between operation cycles ?
We
recommend storing the cart in a relatively dust free
area, at a temperature of 21-25
°C.
The battery charger will also have to be mounted in this
area, and some consideration should also be given to
where the printer should be located. Most printers
don’t last very long in areas where it is quite
dusty….Most of our customers either roll the LCS cart
into an office space adjacent the converter floor, or
build a special room to house the LCS cart.
How is the position of
the mobile cart determined ? Are special marked points
in the floor required ?
The
tracking system measures the position of the cart in 1-2
seconds. This happens automatically during each
measurement. In this way, there is no need for special
marked points, or positions in front of the furnace. It
is simply required that the cart be positioned somewhere
in front of the BOF, the LCS determines its position
automatically.
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Can the display of the
inclinometer be placed in the BOF control console ?
Our
standard inclinometer reads ±80°,
and it not typically linked to the converter control
console. However, this could be accomplished by placing
an additional radio receiver in the converter control
console and a readout for each furnace. We could also
upgrade the inclinometer to give full 360°
output. If this option were purchased, then the
inclinometer system should be powered on continuously.
In this case, the battery powered inclinometer system is
not recommended. Instead, consider the mains-powered
system, which is powered from the plant. This system is
a bit more difficult to install (a rotating contact is
needed), but will run continuously, without batteries.
How many converters can be
scanned with one LCS Mobile Cart ?
One
LCS cart can be used for up to five converters, and an
unlimited number of ladles. However, there must be a
defined set of reflectors for each converter. For the
ladles, we use fiducials mounted on each ladle, or if
the customer prefers, a special ladle stand that gives
us the position of the ladle.
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What is the actual time of
scanning (including all movement of the vessel and
mobile cart) ?
Actual scanning time is between 4-8 minutes, depending
on how fast the operator is. This typically includes
4-6 measurements made at difference furnace tilts, and
different LCS cart positions in front of the furnace.
What are the optimal tapping
angles ?
The
system reports both the starting and stopping tapping
angles. The start tapping angle is the maximum angle
that the furnace can be turned to (after blowing) before
slag starts to pour out of the furnace mouth. The stop
tapping angle is the angle at which slag will start
pouring out of the tap hole.
What is the best distance
between the converter mouth and the LCS mobile cart ?
Approximately 3-5 meters, depending on the size of the
vessel. Smaller vessels require the cart to be close to
the furnace mouth to view the interior of the cone and
upper barrel.
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