U.S. patent number RE44,943 [Application Number 13/591,593] was granted by the patent office on 2014-06-10 for fluid properties evaluation.
This patent grant is currently assigned to Commonwealth Scientific and Industrial Research Organisation. The grantee listed for this patent is Vincent T. O'Brien. Invention is credited to Vincent T. O'Brien.
United States Patent |
RE44,943 |
O'Brien |
June 10, 2014 |
Fluid properties evaluation
Abstract
Fluid flow properties often dictate the performance of
processing operations. The present invention relates to a system
for evaluating properties of a fluid flowing in a pipe. A test cell
(20) which includes two parallel surfaces (5, 6) which are
positioned in the flow. One of the surfaces is moveable relative to
the other, to a position in close proximity to the other, to create
a stagnant flow region between the surfaces. The system further
includes a test input device (10) to apply input motion to one of
the surfaces, and a test output device (13) to measure output
motions from the cell in response to input motions. Furthermore,
the system includes a processing device (9) to calculate
rheological parameters of the fluid from signals produced from the
test input and test output device. There is also a process for
evaluating properties of a flowing fluid.
Inventors: |
O'Brien; Vincent T. (Unley,
AU) |
Applicant: |
Name |
City |
State |
Country |
Type |
O'Brien; Vincent T. |
Unley |
N/A |
AU |
|
|
Assignee: |
Commonwealth Scientific and
Industrial Research Organisation (Australian Capital Territory,
AU)
|
Family
ID: |
50845646 |
Appl.
No.: |
13/591,593 |
Filed: |
August 22, 2012 |
PCT
Filed: |
April 18, 2002 |
PCT No.: |
PCT/AU02/00484 |
371(c)(1),(2),(4) Date: |
April 28, 2004 |
PCT
Pub. No.: |
WO02/086462 |
PCT
Pub. Date: |
October 31, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
10475297 |
Apr 18, 2002 |
7054766 |
May 30, 2006 |
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Foreign Application Priority Data
Current U.S.
Class: |
702/50; 73/54.24;
137/10; 422/68.1 |
Current CPC
Class: |
G01N
11/165 (20130101); G01N 11/04 (20130101); G01N
35/085 (20130101); Y10T 137/0368 (20150401) |
Current International
Class: |
G06F
17/00 (20060101); G01N 11/00 (20060101); G01L
7/00 (20060101) |
Field of
Search: |
;702/33,45,50,51,100,114
;73/54.09,54.24,54.28 ;137/10 ;435/293.1 ;700/281,282
;422/68.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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31075/77 |
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Jun 1979 |
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AU |
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1 213 575 |
|
Jun 2002 |
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EP |
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2 772 129 |
|
Jun 1999 |
|
FR |
|
2306670 |
|
May 1997 |
|
GB |
|
WO 95/12822 |
|
May 1995 |
|
WO |
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WO 97/210990 |
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Jun 1997 |
|
WO |
|
Primary Examiner: Le; John H
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
The invention claimed is:
1. A system for evaluating properties of a flowing fluid
comprising: a section of pipe through which the fluid flows; a test
cell positioned in the pipe and presenting two parallel surfaces in
line with the flow, one of which is moveable relative to the other,
to a position in close proximity to the other, to create a stagnant
flow region between the surfaces.[.,.]..Iadd.;.Iaddend. a test
input means to apply input motions to one of the surfaces; a test
output means to measure output motions from the cell in response to
the input motions; and processing means to calculate rheological
parameters of the fluid from signals produced from the test input
and test output means.Iadd.; wherein the input motions are
substantially perpendicular to the surfaces.Iaddend..
2. A system according to claim 1, further comprising a temperature
sensor positioned in the fluid flow.
3. A system according to claim 1, further comprising a shield
positioned upstream of the test cell to assist in the creation of a
stagnant flow.
4. A system according to claim 1, wherein the test input means is
an actuator.
5. A system according to claim 1, wherein the test input means
includes a motion sensor to determine the waveform of the input
motion.
6. A system according to claim 1, wherein the input motion
comprises a complex waveform.
7. A system according to claim 1, wherein the test output means is
a piezoelectric transducer.
8. A system according to claim 1, wherein the processing means
comprises: a computer; an analogue to digital converter; and a
power amplifier.
9. A system according to claim 8, wherein the processing means
further comprises computer software to perform at least one of the
following: assemble input signal waveforms; store output signal
data; compensate and adjust for drift occurring between the cell
surfaces; and implement sampling regimes for the system to
perform.
10. A test cell to evaluate properties of a flowing fluid,
comprising: a housing having an aperture for fluid to flow through
and two parallel surfaces in the aperture in line with the flow,
one of which is moveable relative to the other to a position in
close proximity to the other to create a stagnant flow between the
surfaces; a test input means to apply input motions to one of the
surfaces; and a test output means to measure output motions related
to calculations of rheological parameters from the cell in response
to the input motions.Iadd.; wherein the input motions are
substantially perpendicular to the surfaces.Iaddend..
11. A test cell according to claim 10, further comprising a
temperature sensor positioned in the fluid flow.
12. A test cell according to claim 10, further comprising a shield
positioned upstream of the test cell to assist in the creation of a
stagnant flow.
13. A test cell according to claim 10, wherein the test input means
is an actuator.
14. A test cell according to claim 10, wherein the test input means
includes a motion sensor to determine the waveform of the input
motion.
15. A test cell according to claim 10, wherein the input motion
comprises a complex waveform.
16. A test cell according to claim 10, wherein the test output
means is a piezoelectric transducer.
17. A test cell according to claim 10, wherein the processing means
comprises: a computer; an analogue to digital converter; and a
power amplifier.
18. A test cell according to claim 17, wherein the processing means
further comprises computer software to perform at least one of the
following: assemble input signal waveforms; store output signal
data; compensate and adjust for drift occurring between the cell
surfaces; and implement sampling regimes for the system to
perform.
19. A process for evaluating properties of a flowing fluid,
comprising the following steps: positioning two parallel surfaces
in line with the flow to define a test cell therebetween; moving
one of the surfaces relative to the other, to a position in close
proximity to the other, to create a stagnant flow region between
the surfaces; applying input motions to one of the surfaces;
measuring output motions from the cell in response to the input
motions; and calculating rheological parameters of the fluid from
signals produced from test input and test output means.Iadd.;
wherein the input motions are substantially perpendicular to the
surfaces.Iaddend..
20. A process according to claim 19, further comprising a
temperature sensor positioned in the fluid flow.
21. A process according to claim 19, further comprising a shield
positioned upstream of the test cell to assist in the creation of a
stagnant flow.
22. A process according to claim 19, wherein the test input means
is an actuator.
23. A process according to claim 19, wherein the test input means
includes a motion sensor to determine the waveform of the input
motion.
24. A process according to claim 19, wherein the input motion
comprises a complex waveform.
25. A process according to claim 19, wherein the test output means
is a piezoelectric transducer.
26. A process according to claim 19, wherein the processing means
comprises: a computer; an analogue to digital converter; and a
power amplifier.
27. A process according to claim 26, wherein the processing means
further comprises computer software to perform at least one of the
following: assemble input signal waveforms; store output signal
data; compensate and adjust for drift occurring between the cell
surfaces; and implement sampling regimes for the system to perform.
Description
This application is a 371 of PCT/AU02/00484, filed Apr. 18, 2002;
the disclosure of which is incorporated herein by reference.
TECHNICAL FIELD
This invention concerns a system for evaluating properties of a
flowing fluid. In another aspect, it concerns a test cell to
evaluate the properties of a flowing fluid. In a further aspect it
concerns a method for evaluating properties of a flowing fluid.
BACKGROUND ART
Rheology concerns the deformation and flow of matter. Materials can
resist deformation in a solid-like manner or in a viscous-like
manner. Solid-like materials store energy under deformation, upon
removal of the stress, the material returns to its undeformed
state. Viscous-like materials dissipate stress during deformation.
Materials with combined solid-like and viscous-like properties are
said to be viscoelastic.
Most materials such as foodstuffs, paints, gels and polymer melts
are viscoelastic in nature. Their viscoelasticity is often
essential to performance criterion and consequently oscillatory
strain techniques have been developed for measuring these
properties. The solid-like or viscous-like nature is quantified
from the stress response to an oscillatory strain. In ideal
solid-like materials, the stress response will be in phase with the
oscillatory strain, ie the largest deformation will coincide with
the largest stress. Viscous-like materials do not store energy and
the stress developed depends on the rate of deformation.
Consequently, the stress response will be out of phase with the
oscillatory strain. In viscoelastic materials, the stress will be
between 0.degree. and 90.degree. out of phase with the deformation,
displaying viscous-like and solid-like properties. Storage modulus
is defined as a measure of the solid-like or in-phase stress
response. The loss modulus measures the fluid-like response.
Rheological, particuarly viscosity, measurements are important for
process control. Flow properties often dictate the performance of
processing operations. Highly viscous products may be undesirable
due to expensive pumping costs, however low viscosity products may
be prone to settling problems. Flow properties may be critical to
performance in the desired end use. For example, the surface
roughness of painted films during and after application is
controlled through tailoring very specific flow resistance in paint
products. Furthermore, flow properties are dictated by the inherent
material microstructures. Consequently, rheological measurements
that gauge material conversion rates and addition levels during
processing may predict many performance criterion after
processing.
SUMMARY OF THE INVENTION
In a first aspect the invention is a system for evaluating
properties of a flowing fluid comprising:
a section of pipe through which the fluid flows;
a test cell positioned in the pipe and presenting two parallel
surfaces in line with the flow, one of which is moveable relative
to the other, to a position in close proximity to the other, to
create a stagnant flow region between the surfaces,
a test input means to apply input motions to one of the
surfaces;
a test output means to measure output motions from the cell in
response to the input motions; and
processing means to calculate rheological parameters of the fluid
from signals produced from the test input and test output
means.
The system is able to measure the rheological properties of the
fluid while it is flowing in the pipe. The advantages of fluid
capture and testing in a process stream are that the fluid remains
unpolluted, requiring low maintenance of the system, that
measurements of complex viscosity and viscoelastic properties can
be made quickly and on demand, and that quantified measurements can
be available for effective process control.
In another aspect, the invention is a test cell to evaluate
properties of a flowing fluid, comprising: p a housing having an
aperture for fluid to flow through and two parallel surfaces in the
aperture in line with the flow, one of which is moveable relative
to the other;
a test input means to apply input motions to one of the surfaces;
and
a test output means to measure output motions from the cell in
response to the input motions.
A temperature sensor may be positioned in the fluid flow to measure
the temperature of the fluid. In high fluid flows, a shield may be
appropriately positioned upstream of the test cell to assist in the
creation of a stagnant flow.
The test input means may be an actuator. The test input means may
include a motion sensor to determine the waveform of the input
motion. The test input means may apply mechanical or electrical
vibrations to the surface and may use rotational, harmonic or
piston methods. The input motion may be a single wave such as a
sine wave, square wave, triangular wave, sawtooth wave, or the
like, or alternative, may be a complex signal having for instance a
waveform formed from the superposition of two or more single sine
waves, square waves, triangular waves, or sawtooth waves, where
each wave is of a different frequency.
An analogue to digital converter and a power amplifier may be
provided to drive the test signal input means.
A shield may be provided near the surfaces to assist in trapping
fluid between the cell surfaces.
The processing means may include a computer, an analogue to digital
converter and a power amplifier. The processing means may further
include computer software to assemble input signal waveforms; store
output signal data; compensate and adjust for drift occurring
between the cell surfaces; and implement sampling regimes for the
system to perform.
In another aspect, the invention is a process for evaluating
properties of a flowing fluid, comprising the following steps:
positioning two parallel surfaces in line with the flow,
moving one of the surfaces relative to the other, to a position in
close proximity to the other, to create a stagnant flow region
between the surfaces,
applying input motions to one of the surfaces;
measuring output motions from the cell in response to the input
motions; and
calculating rheological parameters of the fluid from signals
produced from the test input and test output means.
BRIEF DESCRIPTION OF DRAWINGS
An example of the invention will now be described with reference to
the accompanying drawing, FIG. 1, which is a diagram of a
rheometer.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to FIG. 1, the rheometer 1 is connected directly to a
pipe 2 through which flows a process stream 3. A housing 4 of the
rheometer 1 is fixed to the walls of the pipe 2. Two parallel
smooth plates 5 and 6 extend from the housing into the pipe in line
with the flow to form a test cell 20. The bottom plate 6 may be of
complex design to reduce or eliminate edge effects and compensate
for the non-compressibility of many fluids which may be measured in
this immersed environment.
The rheometer 1 has an actuator stage 10 inside the housing 4 and a
shaft 11, to connect it to the upper moveable plate 5. The shaft is
provided with a thermal barrier so as to limit the heat flow out of
the chamber. The cell also has a temperature sensor 7 such as a
thermocouple or thermistor mounted in the stream. A piezoelectric
AC transducer 13 is attached to the bottom plate 6 in the cell.
Seals are provided to prevent ingress of the measured fluid around
the shafts 11 and 16.
The actuator 10 is provided with a motion sensor 8 to determine the
actual waveform applied to the plate 5. A processing means such as
a computer 9 is connected to the rheometer with an attaching
analogue to digital converter 14 and preamplifier 15 to control and
process results from the rheometer.
If the flow rate of the fluid is too high, preventing a stagnant
region forming between the two plates, a shield 12 may be used to
assist in the trapping of fluid between the plates.
The actuator 10 is capable of providing motion to the cell surfaces
in a direction perpendicular to the centroid axis of the cell, or
alternatively it may be in a direction orthogonal to the axis. The
actuator is generally axisymmetric with the test cell 20 and
situated directly above it to generate oscillatory displacements
with a resolution of greater than a tenth of a micron. The motion
provided by the actuator may be a single sine wave, square wave,
triangular wave, sawtooth wave, or the like, or a complex signal
having for instance any waveform formed from the superposition of
two or more single sine waves, square waves, triangular waves, or
sawtooth waves, of different frequencies.
In Use
Sample collection is achieved by using the actuator stage 10 to
drive the upper plate 5 towards the lower plate 6 and squeezing
them together until a stagnant flow region forms within the test
cell 20. In circumstances where the flow rate of the process stream
3 is too fast, insertion of an appropriately placed shield, or
baffle, 12 may be required to assist in creating the stagnant flow
region. When the stagnant flow region is formed, there may still be
some small flow between the two plates (5, 6), but this drift may
be corrected and compensated for in the rheological calculations by
software.
When fluid capture is achieved, measuring commences by oscillating
the top plate 5 with the desired waveform, x(t). Forces generated
by the oscillation are determined, G(t) from the piezoelectric
transducer 13. Alternatively, the force measuring means may take
the form of measuring the voltage necessary to drive the actuator
10. Oscillation is applied in a random or pseudo random
reciprocating movement to one of the plates in a direction normal
to the other plate by the actuator. Movements include squeeze flow,
extensional flow, rotational, torsional or orthogonal to be used as
the basis of the rheological measurement. For these measurements,
the control of the sample fluid is achieved by controlling the
velocity of sample fluid relative to the time taken for the fluid
to pass through the cell. The signal from the motion sensor is used
in a feedback loop to increase the voltage when the motion
amplitude falls below that required by the waveform definition.
There are no limitations in respect to the signal processing,
allowing any torsional movement to be processed to calculate the
complex modulus of the fluid. Waveforms are assembled by the
computer software and stored as a repeating pattern of numbers
representing amplitude. The rate at which these numbers are read
determines the frequency range. From the oscillation of the top
plate, the complex transfer function may then be calculated as:
.function..omega..function..function..function. ##EQU00001##
automatically, where the operator I indicates Fourier transforms.
The viscosity and viscoelastic parameters are then calculated
using:
.function..omega..times..times..pi..times..times..times..function..omega.
##EQU00002##
This operation can be repeated and averaged several times by the
software to improve resolution of rheological data. After the
software calculates the rheological parameters, the sample is
ejected by first squeezing the plates together driving the tested
sample out of the test cell 20. The plates are then separated
allowing flow in the process stream to scrub the plate surfaces and
prevent residue build up or fouling of the test cell 20.
The rheometer is designed to run continuously as part of a
production process with little or no operator intervention. The
rheometer relies on continuous cycles of sample collection,
measurement and sample ejection. This continuous sampling provides
savings in time and allows the collation of rheological data to be
more accurately calculated through multiple sampling. The sampling
regime may be automatically controlled by computer software, and
administered at various time intervals.
In an alternative embodiment, the rheometer can also be connected
to a bypass stream for on-line operation. This may be suitable when
there are very large amounts of flowing fluid or when there is
difficulty in installing the system to a process stream such as
limited space. Fluid capture and measurement are performed similar
to the preferred embodiment Furthermore, an electromagnetic motor
may replace the alternator 10 to drive the upper plate 5 towards
the lower plate 6.
In another alternative embodiment, the housing 4 of the rheometer 1
may extend into the flow in pipe 2. In such an embodiment, a
diaphragm may cover the bottom surface of the top plate to prevent
flow escaping from the pipe. In a still alternate embodiment, the
plates (5, 6) may be concentric cylinders.
Alternative techniques available for measuring rheological
properties are rotation of the upper plate or harmonic vibration of
the upper plate. Rotational methods apply large rotational strains
to samples thereby generating equilibrium stress. Harmonic types
resonate the upper plate. Fluid viscosity is calculated from either
the change in harmonic frequency, amplitude or current required to
maintain constant amplitude.
In additon to the flat plates described parallel lenses or
concentric cylinders may be used.
It will be appreciated by persons skilled in the art that numerous
variations and/or modifications may be made to the invention as
shown in the specific embodiments without departing from the spirit
or scope of the invention as broadly described. The present
embodiments are, therefore, to be considered in all respects as
illustrative and not restrictive.
* * * * *