Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
TOMOGRAPHIC DETERMINATION OF SCALE BUILD-UP
IN PIPES AND OTHER TANKS, CELLS, VESSELS OR CONTAINERS
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to techniques for determining a scale build-up
in
pipes, tanks, vessels or containers; and more particular to techniques for
determination of a scale build-up in pipes, tanks, vessels or containers using
.. tomographic techniques.
2. Description of Related Art
Tomographic techniques or approaches based on the use of Electrical
Resistance Tomography (ERT), Electrical Capacitance Tomography (ECT) and
Electrical Impedance Tomography (Eli) are becoming widely exploited in
industrial
processes for the analysis of mixing in multi-phase flows, liquid interfaces
and liquid-
froth layers for example.
These techniques or approaches are based at least partly on the difference in
conductivity or electrical (complex) permeability of materials or mediums
under
.. investigation. In such a technique, the aim is to image the cross-section
of the fluid
in, e.g., a pipe, to indicate:
1) The mixing of different fluidic components,
2) Air content, and/or
3) The degree/content of solids in the flow.
By way of example, the use of tomographic analysis using linear-geometry
probe sensors has also been disclosed and is known in the art. In such an
application, the fluid composition in the volume surrounding the probe (the
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measurement volume) can be visualized using tomographic processing. This type
of
probe has been applied to measurements taken in flotation cells, e.g., in
mineral
separation processes. In such an application, as with many others, scale build-
up on
sensor electrodes can give an erroneous tomographic image of the measurement
volume.
Scale build-up on electrodes results in a layer of high resistivity material
on
the electrode, known as the electrode-fluid interface conductivity, as shown
in Figure
1. This layer increases in resistance (drops in conductivity) as the scale
deposits
build-up. By way of example, Figures 1 b, 1 c and id respectively show such a
pipe
having substantially zero scale build-up, low scale build-up, and high scale
build-up.
In order to create tomographic images, it is known to use, e.g., an in-pipe
tomography system as shown in Figure la, and to space a set of electrodes in
regular intervals around the circumference of the pipe, e.g., in a so-called
regular
configuration. See also that shown in Figures 4a. The regular configuration
may
include, or take the form of, evenly or symmetrically spaced electrodes in
regular
intervals and/or electrodes having substantially the same width or length. In
operation, current is sent between a pair of electrodes and the potentials
generated
across other pairs are monitored. When the tomographic electrode array is
first
deployed, the impedance between two adjacent electrodes varies with the
conductivity of the fluid in the measurement volume. For a pipe-based array as
shown in Figure la, the conductivity of the fluid, Kr, fluctuates with the
variability in
the process fluid. In most normal or typical applications, the range in
conductivity
(AK') of the process fluid is bounded by the constituents of fluid (in the
case of mixed
fluids), or the degree of dissolved or suspended particles in the flow. As an
example,
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see the graph in Figure 2, which shows process fluid conductivity in relation
to time
and the variation in the conductivity of a process fluid.
This range of variance in conductivity, AKf, occurs at fluid mixing/process
variability time frames, typically in sub-second to minute time frames. As
scale
builds up on the electrodes, the electrode-fluid interface conductivity (Ke)
drops the
measured conductivity, K, of the fluid, consistent with the relationship set
forth in the
equation, as follows:
K = Kf * Ke (Kf + Ke).
The measured conductivity, K, typically appears to fall over time, consistent
with that
set forth in the graph in Figure 3, which shows apparent process fluid
conductivity in
relation to time and the drop in apparent conductivity with increasing scale,
while the
fluidic time-varying component remains, but is now suppressed in amplitude due
to
the scale build-up.
Tomographic processing algorithms are known in the art and have been
developed to compensate for this scale build-up by compensating for the
electrode-
fluid interface conductivity, using a model that slow increments of an
inputted value
of the effective electrode-fluid interface conductivity Kf over time to
'restore' the
correct variability in the fluidic conductivity. As the scale builds up over
time in an
incrementing fashion, and initiates on 'clean' electrodes, some boundaries are
set for
electrode-fluid interface conductivity Ke, as follows:
e.g.: at t= 0, Ke = 0, and
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at t2 > ti Ke(t2) < Ke(ti).
In this way, the electrode-fluid interface conductivity Ke can be inferred,
and
the compensation applied to a measure of the fluid conduction (and this
composition).
In most industrial processes, the potential for scale build-up is known, as
well
as the types of deposits (e.g., calcium carbonate) that are building up.
In view of the aforementioned understanding, there is a need in the industry
for a different and better way to determine the scale build-up, e.g., in a
pipe, tank,
cell or vessel.
SUMMARY OF THE INVENTION
According to some embodiments of the present invention, a technique is
provided such that an inferred electrode-fluid interface conductivity may be
taken
and the scale build-up may be calculated from an a priori assessment (i.e.
deduction) of the conductivity of the scale material with thickness.
According to some embodiments of the present invention, for scale build up, it
has been determined that an irregular configuration of a set of electrodes
around the
circumference of the pipe, tank, cell or vessel may provide some important
advantages. By way of example, the irregular configuration may include, or
take the
form of, some combination of unevenly or asymmetrically spaced electrodes in
irregular intervals.
Moreover still, according to some embodiments of the present invention, the
use of electrodes with differing or variable widths or lengths arranged in
patterns
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may also be advantageous for this type of measurement, as the effective
overall
electrode-fluid interface conductivity will depend on the contact area of
electrodes.
In operation, such techniques or approaches will allow the scale build-up in a
pipe, tank, cell or vessel to be assessed, and, e.g., a chemical to be
injected to
control the scale build-up in a closed loop manner.
Examples of Particular Embodiments
According to some embodiments, the present invention may include, or take
the form of, apparatus featuring a signal processor or processing module
configured
at least to:
receive signaling containing information about the conductivity of a fluid
contained, processed or flowing in a pipe, tank, cell or vessel having
electrodes around the circumference of the pipe, tank, cell or vessel in an
irregular configuration; and
determine a scale build-up in the pipe, tank, cell or vessel using a
tomographic processing technique, based at least partly on the signaling
received.
According to some embodiment of the present invention, the signal processor
module may be configured to provide corresponding signaling containing
information
about the scale build-up in the pipe, tank, cell or vessel using the
tomographic
processing technique, e.g., including where the corresponding signaling
contains
information about a chemical to be injected to control the scale build-up,
including in
a closed loop manner.
The present invention may also include one or more of the following features:
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The irregular configuration may include, or take the form of, unevenly or
asymmetrically spaced electrodes in irregular intervals. By way of example,
the
electrodes may include a first electrode pair spaced at a first distance, and
a second
electrode pair spaced at a second distance that is different than the first
distance.
The irregular configuration may include, or take the form of, electrodes
having
differing or varying widths or lengths. By way of example, the electrodes may
include a first electrode pair having a first width or length, and a second
electrode
pair having a second width or length that is different than the first width or
length.
The irregular configuration may include, or take the form of, unevenly or
asymmetrically spaced electrodes in irregular intervals in combination with
electrodes having differing or varying widths or lengths. By way of example,
the
electrodes may include a first electrode pair spaced at a first distance and
having a
first width or length, and a second electrode pair spaced at a second distance
that is
different than the first distance and having a second width or length that is
different
than the first width or length. Alternatively, and by way of further example,
the
electrodes may include a first electrode pair spaced at a first distance, and
a second
electrode pair spaced at a second distance that is different than the first
distance;
and also include a third electrode pair having a first width or length, and a
fourth
electrode pair having a second width or length that is different than the
first width or
length. Embodiments are envisioned, and the scope of the invention is intended
to
include, using other types or kinds of irregular configurations within the
spirit of the
underlying invention.
The signal processor module may be configured to determine the scale build-
up in the pipe, tank, cell or vessel using the tomographic processing
technique,
based at least partly on determining the conductivity of the fluid between the
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electrodes, which depends on the conductivity of the fluid through a path
between
the electrodes and twice an electrode-fluid interface conductivity or scale
layer.
The signal processor module may be configured to determine the scale build-
up in the pipe, tank, cell or vessel using the tomographic processing
technique,
based at least partly on assessing an average fluid conductivity in order to
yield a
series of equations that can be solved for determining an electrode-fluid
interface
conductivity or scale layer.
The signal processor module may be configured to determine the electrode-
fluid interface conductivity or scale layer based at least partly on the
contact area of
electrodes.
The apparatus may include or comprise the irregular configuration having
electrodes with unevenly or asymmetrically spaced electrodes in irregular
intervals.
The apparatus may include or comprise the irregular configuration having
electrodes with differing or varying widths or lengths.
The apparatus may include or comprise the irregular configuration having
electrodes with unevenly or asymmetrically spaced electrodes in irregular
intervals in
combination with electrodes with differing or varying widths or lengths.
The signal processor or processing module may be configured with at least
one processor and at least one memory including computer program code, the at
least one memory and computer program code configured, with the at least one
processor, to cause the apparatus at least to receive the signaling and
determine the
scale build-up in the pipe, tank, cell or vessel using the tomographic
processing
technique, based at least partly on the signaling received.
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The tomographic processing technique may include electrical resistance
tomography (ERT), electrical capacitance tomography (ECT), or electrical
impedance tomography (EIT).
The Method
According to some embodiments, the present invention may include, or take
the form of, a method or process that includes steps for receiving with a
signal
processor or processing module signaling containing information about the
conductivity of a fluid contained, processed or flowing in a pipe, tank, cell
or vessel
having electrodes around the circumference of the pipe, tank, cell or vessel
in an
irregular configuration; and determining a scale build-up in the pipe, tank,
cell or
vessel using a tomographic processing technique, based at least partly on the
signaling received.
The method may also include one or more of the features set forth herein,
according to some embodiments of the present invention.
BRIEF DESCRIPTION OF THE DRAWING
The drawing includes Figures 1-6, which are not necessarily drawn to scale,
as follows:
Figure 1 shows an in-pipe tomography system having electrodes evenly
spaced about the circumference of a pipe for measuring scale build-up in the
pipe
that is known in the art.
Figure 2 shows a graph of process fluid conductivity in relation to time and
the
variation in the conductivity of a process fluid, consistent with that known
in the art.
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Figure 3 shows a graph of apparent process fluid conductivity in relation to
time and the drop in the conductivity with increasing scale build-up,
consistent with
that known in the art.
Figure 4 is a diagram of a pipe having electrodes evenly spaced about the
circumference of a pipe, consistent with that known in the art.
Figure 5 is a diagram of a pipe having electrodes using segmented spacing,
or generally irregularly spaced electrodes, and/or electrodes of differing
widths or
lengths about the circumference of a pipe for measuring scale build-up,
according to
some embodiments of the present invention.
Figure 6 is a block diagram of apparatus having a signal processor or
processing module configured to implement some embodiments of the present
invention.
DETAILED DESCRIPTION OF BEST MODE OF THE INVENTION
Figure 5
Figure 5 shows an example of electrodes, some of which are labeled El, E2,
E3, E4, having segmented spacing in an irregular configuration, according to
some
embodiments of the present invention. The electrodes El, E2, E3, E4 are shown
in
the irregular configuration on the inside wall of a pipe 5. Electrodes pairs
are
separated by a respective gap, where the gap between some electrodes pairs
like
El and E2 are different than the gap between other electrode pairs like
electrodes
E3 and E4, so as to form the segmented spacing. It is understood that the
circumference of the inside wall of the pipe 5 is known, and the associate
gaps
between electrodes pairs like El and E2 and the other electrode pairs like
electrodes
E3 and E4 are also known. As shown, the distance between the electrodes pair
El
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and E2 may be defined by a path P, and the distance between the electrodes
pair E3
and E4 may be defined by a path 2P, e.g., which is about twice in distance or
length
than path P.
In Figure 5, the conductivity measured between two closely-spaced
electrodes, like El and E2, may be determined by the conductivity of the fluid
through the path P, and twice the electrode-fluid interface conductivity
(scale layer).
In comparison, the conductivity between two less closely-spaced electrodes,
like E3
and E4 (which are farther apart from one another), may be determined by the
conductivity of the fluid through the path approximately 2P in length, and
twice the
electrode-fluid interface conductivity (scale layer). As a person skilled in
the art
would appreciate, if the average fluid conductivity is assessed using
tomographic
processing, this can be used to yield a series of equations that can be solved
for
determining the electrode-fluid interface conductivity, consistent and in
accordance
with some embodiments of the present invention.
Figure 6: The Basic Apparatus 10
Figure 6 shows apparatus 10 having a signal processor or processing module
10a for implementing the basic signal processing functionality according to
some
embodiments of the present invention. The signal processor or processing
module
10a may be configured at least to
receive signaling containing information (61) about the conductivity of a
fluid contained, processed or flowing in a pipe, tank, cell or vessel having
electrodes around the circumference of the pipe, tank, cell or vessel in an
irregular configuration; and
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determine a scale build-up in the pipe, tank, cell or vessel (62) using a
tomographic processing technique, based at least partly on the signaling
received.
By way of example, the signaling may be received from the irregular
configuration, or from some other signal processing device that receives the
signaling, processes the same, and provides some further processed signaling
containing information about the conductivity of the fluid contained,
processed or
flowing in the pipe, tank, cell or vessel having the electrodes around the
circumference of the pipe, tank, cell or vessel in the irregular
configuration. By way
of example, the further processed signaling may include amplifying, filtering,
smoothing or some other processing of the signaling received from the
irregular
configuration.
The signal processor or processing module 10a may also be configured to
provide corresponding signaling containing corresponding information about the
scale build-up in the pipe, tank, cell or vessel (63) using the tomographic
processing
technique, e.g., including where the corresponding signaling contains
information
about a chemical to be injected to control the scale build-up, including in a
closed
loop manner. The scope of the invention is not intended to be limited to the
type or
kind of use of the corresponding signaling containing information about the
scale
build-up in the pipe, tank, cell or vessel, including for further processing,
printing or
displaying, as well as for other types or kinds of uses either now known or
later
developed in the future.
Further, the scope of the invention is not intended to be limited to the type
or
kind of fluid contained, processed or flowing in the pipe, tank, cell or
vessel. For
example, the scope of the invention is intended to include processing fluids
that are
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either now known or later developed in the future. Moreover, the scope of the
invention is intended to include sensing and determining the scale build-up in
pipes,
tanks, cells, vessels, etc., that are either now known or later developed in
the future.
Moreover still, the scope of the invention is not intended to be limited to
the type or
kind of industrial process of which the fluid is being processed, including a
process
or processes that is or are either now known or later developed in the future.
The apparatus 10 may also include other circuits, components or modules
10b to implement the functionality of the signal processor or processing
module 10a
(64) either now known or later developed in the future, e.g., including memory
modules, input/output modules, data and busing architecture and other signal
processing circuits, wiring or components, consistent with that known by a
person
skilled in the art, and/or consistent with that set forth herein.
Signal Processor or Signal Processing Module 10a
By way of example, and consistent with that described herein, the
functionality
of the signal processor or processing module 10a may be implemented to receive
the signaling, process the signaling, and/or provide the corresponding
signaling,
using hardware, software, firmware, or a combination thereof, although the
scope of
the invention is not intended to be limited to any particular embodiment
thereof. In a
typical software implementation, the signal processor or processing module 10a
may
include, or take the form of, one or more microprocessor-based architectures
having
a microprocessor, a random access memory (RAM), a read only memory (ROM),
input/output devices and control, data and address busing architecture
connecting
the same. A person skilled in the art would be able to program such a
microprocessor-based implementation to perform the functionality set forth
herein, as
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well as other functionality described herein without undue experimentation.
The
scope of the invention is not intended to be limited to any particular
implementation
using technology either now known or later developed in the future. Moreover,
the
scope of the invention is intended to include a signal processor, device or
module
10a as either part of the aforementioned apparatus, as a stand alone module,
or in
the combination with other circuitry for implementing another module.
Techniques for receiving signaling in such a signal processor or processing
module 10a are known in the art, and the scope of the invention is not
intended to be
limited to any particular type or kind thereof either now known or later
developed in
the future. Based on this understanding, a person skilled in the art would
appreciate,
understand and be able to implement and/or adapt the signal processor or
processing module 10a without undue experimentation so as to receive signaling
containing information about the conductivity of a fluid flowing in a pipe,
tank, cell or
vessel having electrodes around the circumference of the pipe, tank, cell or
vessel in
an irregular configuration, consistent with that set forth herein.
Techniques, including techniques based on tomography or tomographic
processing techniques, for determining information based on analyzing or
processing
signaling received in such a signal processor or processing module 10a are
also
known in the art, and the scope of the invention is not intended to be limited
to any
particular type or kind thereof either now known or later developed in the
future.
Based on this understanding, a person skilled in the art would appreciate,
understand and be able to implement and/or adapt the signal processor or
processing module 10a without undue experimentation so as to determine a scale
build-up in the pipe, tank, cell or vessel using a tomographic processing
technique,
based at least partly on the signaling received, consistent with that set
forth herein.
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It is also understood that the apparatus 10 may include one or more other
modules, components, processing circuits, or circuitry 10b for implementing
other
functionality associated with the underlying apparatus that does not form part
of the
underlying invention, and thus is not described in detail herein. By way of
example,
the one or more other modules, components, processing circuits, or circuitry
may
include random access memory, read only memory, input/output circuitry and
data
and address buses for use in relation to implementing the signal processing
functionality of the signal processor, or devices or components, etc.
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Tomography or Tomographic Processing Techniques
Tomography or tomographic processing techniques are known in the art, and
generally understood to refer to imaging by sections or sectioning, through
the use of
any kind of penetrating wave. A device used in tomography is called a
tomograph,
while the image produced is a tomogram. Such methods or techniques may be
used,
e.g., in radiology, archeology, biology, geophysics, oceanography, materials
science,
astrophysics, quantum information and other sciences. In most cases, such
methods or techniques may be based on the mathematical procedure called
tomographic reconstruction. Tomographic reconstruction algorithms are known in
the art for determining the imaging by sections or sectioning, through the use
of any
kind of penetrating wave. By way of example, the reader is referred to U.S.
Patent
Nos. 6,078,397; 5,181,778; 4,386,854; and 4,328,707, which all relate to
tomographic techniques. The scope of the invention is not intended to be
limited to
the type or kind of tomographic reconstruction algorithms, including those
based at
least partly on using ultrasonic waves, either now known or later developed in
the
future.
See also the aforementioned PCT application no. PCT/US12/52074 (712-
2.358-1 (CCS-0069W0), filed 23 August 2012, as well as PCT application no.
PCT/US12/60811 (712-2_363-1 (CCS-0068/70/62W0), filed 18 October 2012, which
disclose applications based at least partly on using a tomography or
tomographic
processing technique, which was developed and is owned by the assignee of the
instant patent application.
Moreover, embodiments are envisioned, and the scope of the invention is
intended to include, using other types or kinds of tomography or tomographic
processing technique either now known or later developed in the future.
Finally, the
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scope of the invention is not intended to be limited to any particular type or
kind of
tomography or tomographic processing technique either now known or later
developed in the future.
A person skilled in the art without undue experimentation would be able to
adapt one or more of the aforementioned tomography or tomographic processing
technique in order to implement the present invention, including to configure
a signal
processing module at least to receive signaling containing information about
the
conductivity of a fluid contained, processed or flowing in a pipe, tank, cell
or vessel
having electrodes around the circumference of the pipe, tank, cell or vessel
in an
irregular configuration; and determine a scale build-up in the pipe, tank,
cell or vessel
using a tomographic processing technique, based at least partly on the
signaling
received.
Applications
By way of example, the present invention may be used in, or form part of, or
used in conjunction with, industrial processes like a mineral extraction
processing
system for extracting or separating minerals in a fluidic medium that are
either now
known or later developed in the future, including any mineral process, such as
those
related to processing substances or compounds that result from inorganic
processes
of nature and/or that are mined from the ground, as well as including either
other
extraction processing systems or other industrial processes, where the
extraction, or
separating, or sorting, or classification, of product by size, or density, or
some
electrical characteristic, is critical to overall industrial process
performance.
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The Scope of the Invention
While the invention has been described with reference to an exemplary
embodiment, it will be understood by those skilled in the art that various
changes
may be made and equivalents may be substituted for elements thereof without
departing from the scope of the invention. In addition, may modifications may
be
made to adapt a particular situation or material to the teachings of the
invention
without departing from the essential scope thereof. Therefore, it is intended
that the
invention not be limited to the particular embodiment(s) disclosed herein as
the best
mode contemplated for carrying out this invention.
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