U.S. patent application number 11/692826 was filed with the patent office on 2008-10-02 for micronaire measurement.
This patent application is currently assigned to USTER TECHNOLOGIES AG. Invention is credited to Preston S. Baxter, Hossein M. Ghorashi, James T. Wender.
Application Number | 20080236252 11/692826 |
Document ID | / |
Family ID | 39464887 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080236252 |
Kind Code |
A1 |
Wender; James T. ; et
al. |
October 2, 2008 |
Micronaire Measurement
Abstract
A method of determining a testing volume for a micronaire
measurement by containing a fiber sample within a micronaire
chamber having a length and at least one movable end wall. A flow
is initiated along the length of the micronaire chamber. The fiber
sample is compressed within the micronaire chamber by advancing the
movable end wall, and the advancement of the movable end wall is
stopped when at least one property of the flow attains a set point.
The position of the movable end wall defines the testing volume. In
this manner, there is provided a convenient method of setting a
testing volume and acquiring the information needed to take a
micronaire measurement.
Inventors: |
Wender; James T.; (Seymour,
TN) ; Baxter; Preston S.; (Friendsville, TN) ;
Ghorashi; Hossein M.; (Knoxville, TN) |
Correspondence
Address: |
LUEDEKA, NEELY & GRAHAM, P.C.
P O BOX 1871
KNOXVILLE
TN
37901
US
|
Assignee: |
USTER TECHNOLOGIES AG
Uster
CH
|
Family ID: |
39464887 |
Appl. No.: |
11/692826 |
Filed: |
March 28, 2007 |
Current U.S.
Class: |
73/37 ; 73/149;
73/159 |
Current CPC
Class: |
G01N 33/362 20130101;
G01N 15/0826 20130101 |
Class at
Publication: |
73/37 ; 73/159;
73/149 |
International
Class: |
G01M 3/02 20060101
G01M003/02 |
Claims
1. A method of determining a testing volume for a micronaire
measurement, the method comprising the steps of: containing a fiber
sample within a micronaire chamber having a length and at least one
movable end wall, initiating a flow along the length of the
micronaire chamber, compressing the fiber sample within the
micronaire chamber by advancing the movable end wall, and stopping
the advancement of the movable end wall when at least one property
of the flow attains a set point, a position of the movable end wall
thereby defining the testing volume.
2. The method of claim 1, wherein the at least one property of the
flow is pressure.
3. The method of claim 1, wherein the at least one property of the
flow is volumetric flow rate.
4. The method of claim 1, wherein the movable end wall is advanced
with a stepper motor.
5. The method of claim 1, wherein the flow is a flow of air.
6. A method of taking a micronaire measurement, the method
comprising the steps of: containing a fiber sample within a
micronaire chamber having a length and at least one movable end
wall, initiating a flow along the length of the micronaire chamber,
compressing the fiber sample within the micronaire chamber by
advancing the movable end wall, stopping the advancement of the
movable end wall when at least one property of the flow attains a
set point, a position of the movable end wall thereby defining the
testing volume, and using the at least one property of the flow and
the testing volume to calculate the micronaire measurement.
7. A method of preparing a fiber sample for a micronaire
measurement, the method comprising the step of forming the fiber
sample into a plug having a cross-sectional shape and size that are
substantially similar to a cross-sectional shape and size of a
micronaire chamber in which the micronaire measurement is to be
taken, before inserting the plug into the micronaire chamber.
8. A method of preparing a fiber sample for a micronaire
measurement, the method comprising the steps of: placing an amount
of unformed fiber as a fiber sample in a fiber sample loader, and
bringing together forming surfaces of the fiber sample loader to
form the fiber sample into an elongate plug having a
cross-sectional shape and size that are substantially similar to a
cross-sectional shape and size of a micronaire chamber in which the
micronaire measurement is to be taken, before inserting the plug
into the micronaire chamber.
9. A method of preparing a fiber sample for a micronaire
measurement, the method comprising the steps of: placing an amount
of unformed fiber as a fiber sample in a fiber sample loader,
bringing a first lateral forming surface of the fiber sample loader
toward a second lateral forming surface of the fiber sample loader
and forming the fiber sample between the first lateral forming
surface and the second lateral forming surface to form three sides
of the fiber sample, bringing a vertical forming surface of the
fiber sample loader down between the first lateral forming surface
and the second lateral forming surface and onto the fiber sample to
form a fourth side of the fiber sample, thereby forming the fiber
sample into an elongate plug having a cross-sectional shape and
size that are substantially similar to a cross-sectional shape and
size of a micronaire chamber in which the micronaire measurement is
to be taken, and inserting the plug into the micronaire chamber
with a plunger having a cross-sectional shape and size that are
substantially similar to the cross-sectional shape and size of a
micronaire chamber in which the micronaire measurement is to be
taken.
Description
FIELD
[0001] This invention relates to the field of fiber property
measurement. More particularly, this invention relates to
micronaire measurement of fibers.
BACKGROUND
[0002] Micronaire readings are derived from Koxeny's equation,
which provides an approximation for the permeability of powders
having a negligible number of blind pores. This equation
characterizes the relationship of air flow resistance over a
surface with a known mass in a known volume, as in:
M=(RM).sup.x
[0003] when:
RM = [ ( HMC - LMC ) ( LMP - HMP ) ] [ LMC + ( LMP - P ) ]
##EQU00001##
[0004] and:
X=1+[(W-10)100][0.00125-|3.5-RM|0.00015]
[0005] where, over a sample weight range of about eight grams to
about twelve grams:
[0006] M=Corrected micronaire value
[0007] RM=Raw micronaire value
[0008] HMC=High calibration cotton value
[0009] LMC=Low calibration cotton value
[0010] LMP=Pressure of low calibration cotton value
[0011] HMP=Pressure of high calibration cotton value
[0012] P=Pressure of cotton under test
[0013] W=Weight of cotton under test, grams
[0014] Even though there are certain properties of the fiber
sample, cotton for example, that must be known or derived in order
to produce a micronaire value, these properties can be determined
in a variety of different ways--some ways easier or more convenient
than others. Likewise, the method by which the micronaire readings
are taken can also vary in efficiency, speed, or convenience of
operation.
[0015] What is needed, therefore, is a system for measuring
micronaire that provides benefits, such as those mentioned above,
at least in part.
SUMMARY
[0016] The above and other needs are met by a method of determining
a testing volume for a micronaire measurement by containing a fiber
sample within a micronaire chamber having a length and at least one
movable end wall. A flow is initiated along the length of the
micronaire chamber. The fiber sample is compressed within the
micronaire chamber by advancing the movable end wall, and the
advancement of the movable end wall is stopped when at least one
property of the flow attains a set point. The position of the
movable end wall defines the testing volume.
[0017] In this manner, there is provided a convenient method of
setting a testing volume and acquiring the information needed to
take a micronaire measurement.
[0018] In various embodiments, the at least one property of the
flow is pressure or volumetric flow rate. The movable end wall is
advanced with a stepper motor in one embodiment. The flow is
preferably a flow of air. Preferably, the at least one property of
the flow and the testing volume are used to calculate the
micronaire measurement.
[0019] According to another aspect of the invention there is
described a method of preparing a fiber sample for a micronaire
measurement by forming the fiber sample into a plug having a
cross-sectional shape and size that are substantially similar to a
cross-sectional shape and size of a micronaire chamber in which the
micronaire measurement is to be taken, before inserting the plug
into the micronaire chamber.
[0020] According to another aspect of the invention there is
described a method of preparing a fiber sample for a micronaire
measurement by placing an amount of unformed fiber as a fiber
sample in a fiber sample loader, and bringing together forming
surfaces of the fiber sample loader to form the fiber sample into
an elongate plug having a cross-sectional shape and size that are
substantially similar to a cross-sectional shape and size of a
micronaire chamber in which the micronaire measurement is to be
taken, before inserting the plug into the micronaire chamber.
[0021] According to another aspect of the invention there is
described a method of preparing a fiber sample for a micronaire
measurement by placing an amount of unformed fiber as a fiber
sample in a fiber sample loader. A first lateral forming surface of
the fiber sample loader is brought toward a second lateral forming
surface of the fiber sample loader and the fiber sample is formed
between the first lateral forming surface and the second lateral
forming surface to form three sides of the fiber sample. A vertical
forming surface of the fiber sample loader is brought down between
the first lateral forming surface and the second lateral forming
surface and onto the fiber sample to form a fourth side of the
fiber sample, thereby forming the fiber sample into an elongate
plug having a cross-sectional shape and size that are substantially
similar to a cross-sectional shape and size of a micronaire chamber
in which the micronaire measurement is to be taken. The plug is
inserted into the micronaire chamber with a plunger having a
cross-sectional shape and size that are substantially similar to
the cross-sectional shape and size of a micronaire chamber in which
the micronaire measurement is to be taken.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Further advantages of the invention are apparent by
reference to the detailed description when considered in
conjunction with the figures, which are not to scale so as to more
clearly show the details, wherein like reference numbers indicate
like elements throughout the several views, and wherein:
[0023] FIG. 1 depicts a micronaire measurement system according to
a preferred embodiment of the present invention, with the loader in
the sample reception position.
[0024] FIG. 2 depicts a micronaire measurement system according to
a preferred embodiment of the present invention, with the loader in
the lateral plug 18 formation position.
[0025] FIG. 3 depicts a micronaire measurement system according to
a preferred embodiment of the present invention, with the loader in
the vertical plug 18 formation position.
[0026] FIG. 4 depicts a micronaire measurement system according to
a preferred embodiment of the present invention, with the loader in
the plug 18 insertion position.
[0027] FIG. 5 depicts a micronaire measurement system according to
a preferred embodiment of the present invention, with the plug 18
in the micronaire chamber 28.
[0028] FIG. 6 depicts a micronaire measurement system according to
a preferred embodiment of the present invention, with the loader in
the plug 18 expulsion position.
[0029] FIG. 7 is a functional block diagram of a micronaire
measurement system according to a preferred embodiment of the
present invention.
DETAILED DESCRIPTION
Sample Loading and Unloading
[0030] With reference now to FIG. 1, there is depicted a micronaire
measurement system 10 according to a preferred embodiment of the
present invention. As depicted in FIG. 1, the sample loading
mechanism 12 is in the sample reception position, with the lateral
plug formation member 14 and the vertical plug formation member 16
extended. With the loader 12 in this position, the loader 12 is
adapted to receive the fiber sample 18, on which micronaire
measurements are to be made. The fiber sample 18 may be any one or
blend of more than one fiber types, but in the preferred embodiment
the fiber sample 18 is cotton fiber.
[0031] The various elements of the loader 12 are preferably adapted
so as to form the fiber sample 18 into a plug 18 that is
substantially the same cross-sectional shape as the micronaire
chamber 28 into which the plug 18 will be loaded for measurement of
the micronaire readings. For example, in the depicted embodiment,
the micronaire chamber 28 has a generally circular cross-sectional
shape, and thus the loader 12 preferably forms the fiber sample 18
into a plug 18 having a generally circular cross-sectional
shape.
[0032] To accomplish this, an interior lateral wall 20 of the
loader 12 has a rounded bottom corner, to approximate the interior
of the micronaire chamber 28 at that equivalent location.
Similarly, the exterior lateral wall 22 of the loader 12 also has a
rounded bottom corner, again to approximate the interior of the
micronaire chamber 28 at that equivalent location. It is
appreciated that if the micronaire chamber 28 has a different
cross-sectional shape, the elements described would preferably have
different shapes than those described herein, which different
shapes are again selected so as to approximate the equivalent
locations of the micronaire chamber 28. Thus, the desired function
is the substantial pre-formation of the fiber sample 18 into a plug
18 that has the general shape of the micronaire chamber 28.
[0033] As depicted in the FIG. 2, and according to the
configuration of the present example, the exterior lateral wall 22
of the loader 12 is brought toward the interior lateral wall 20 of
the loader 12, thus laterally forming the fiber sample 18 into the
shape of the micronaire chamber 28. More specifically, the bottom
portion of the fiber sample 18 is formed into the shape of the
micronaire chamber 28, by the two rounded bottom corners of the
interior lateral wall 20 and the exterior lateral wall 22 that have
been brought together.
[0034] As depicted in FIG. 2, the top formation member 24
preferably also has elements that assist in forming the fiber
sample 18 into the shape of the micronaire chamber 28. In the
example depicted, the top formation member 24 has a rounded
interior surface, to approximate the interior of the micronaire
chamber 28 at that equivalent location.
[0035] As depicted in FIG. 3, the top formation member 24 is
brought down onto the fiber sample 18, to complete the formation of
the fiber sample 18 into the shape of the micronaire chamber 28. It
is appreciated that the order of the compaction by which the fiber
sample 18 is formed into a plug 18 with the same cross-sectional
shape as the micronaire chamber 28 is by way of example only, and
that in various embodiments the plug 18 can be vertically shaped
first and then laterally shaped, or the shaping members can be
oriented into a configuration that is something other than
orthogonal. All such configurations are within the contemplated
scope of the present invention.
[0036] Also depicted in FIG. 3 is the forward plunger 26, which
preferably also is configured to have a cross-sectional shape that
is substantially equivalent to the cross-sectional shape of the
micronaire chamber 28. As depicted in FIG. 3, the forward plunger
26 is preferably perforated, for purposes as described in more
detail hereafter.
[0037] FIG. 4 depicts the loader 12 where the forward plunger 26
has been extended, thus driving the fiber sample 18, which has been
formed by the loader into substantially the shape of the micronaire
chamber 28, from the loader 12 and into the micronaire chamber 28.
In alternate embodiments, however, the loader 12, after being
configured to compact the fiber sample 18, then becomes the
micronaire chamber 28, and no separate micronaire chamber 28 is
required. In such an embodiment, the various moving elements of the
loader 12 are preferably fashioned from materials that form
substantially air-tight seals at the interfaces between them, or
are fitted with edge moldings of such material.
[0038] As depicted in FIG. 5, in those embodiments where there is a
separate micronaire chamber 28 into which the forward plunger 26
drives the fiber sample that has been pre-formed into a plug 18,
the plug 18 meets the rear plunger 30 at the back of the micronaire
chamber 28, and begins to be compacted in its length between the
forward plunger 26 and the rear plunger 30 as the forward plunger
26 moves forward. In alternate embodiments, the forward plunger 26
can be brought to a point in the micronaire chamber 28 where the
plug 18 has not yet compacted, and then the rear plunger 30 can be
moved to compact the plug 18 against the forward plunger 26.
Various other embodiments are also within the scope of this
disclosure, such as where both plungers 26 and 30 move toward each
other, or move in the same direct at differing speeds that produce
a compaction of the fibers in the plug 18.
[0039] The methods by which the apparatus 10 takes the micronaire
measurements are described in more detail hereafter. After the
micronaire measurements have been taken on the plug 18, the plug 18
is preferably expelled from the apparatus 10. This can be
accomplished be either withdrawing one of the forward plunger 26
and the rear plunger 30, and using the other plunger to expel the
plug 18 from one or both of the micronaire chamber 28 or the loader
12. Alternately, and especially in those embodiments where the
loader 12 comprises the micronaire chamber 28, the combined loader
12--micronaire chamber 28 can be opened up and the plug 18 can be
withdrawn, either by gravity or some other means.
[0040] FIG. 6 depicts an embodiment where the rear plunger 30 is
withdrawn from the back of the bore of the micronaire chamber 28,
and the forward plunger 26 pushes the plug 18 out the back of the
bore of the micronaire chamber 28. The plug 18, similar to that as
described in alternate embodiments above, can either fall from the
micronaire chamber 28 or be withdrawn by some other removal means,
such as a mechanical device or a vacuum-induced air flow.
[0041] In the preferred embodiment, the fiber sample 18 is weighed
as a part of the micronaire measurement. Although the weight of the
sample can be approximated in a variety of different ways, it has
been determined that actually weighing the fiber sample 18 tends to
produce more accurate micronaire readings. Weighing the fiber
sample 18 can be accomplished either before or after the fiber
sample 18 is formed into a plug 18 by the loader 12, and either
before or after the plug 18 is processed in the micronaire chamber
28.
[0042] If the weight of the fiber sample 18 is not measured until
after the micronaire measurements are taken in the micronaire
chamber 28, such as after the plug 18 has been expelled from the
micronaire chamber 28, then an actual micronaire reading might not
be presented until after the fiber sample 18 has been weighed.
Alternately, various means can be used to estimate the weight of
the fiber sample 18, and those estimates can be used to provide a
calculated micronaire reading for the fiber sample 18. Further yet,
an estimated weight can be used for a preliminary calculation,
which is then fine-tuned by the use of the actual weight of the
fiber sample 18 after it has been weighed.
Micronaire Measurement
[0043] The apparatus 10 described above can be used in a variety of
different ways to take micronaire readings. FIG. 7 depicts a
functional block diagram of portions of the apparatus 10, which
will be used to describe the micronaire measurements. In taking
micronaire measurements, several parameters are preferably known,
including the weight of the fiber sample 18, the volume of the
portion of the micronaire chamber 28 in which the tests are
conducted, the volumetric rate of the air flow that enters 32 and
exits 34 the micronaire chamber 28, and the pressure differential
within the micronaire chamber 28 as measured on a pressure
differential meter 40 between an upstream pressure port 36 and a
downstream pressure port 38. Information such as this is used in
the equations as given above to calculate the micronaire of the
fiber sample 18.
[0044] Preferably, the fiber sample 18 is compacted within the
micronaire chamber 28 to a relatively consistent degree between the
forward plunger 26 and the rear plunger 30, for all micronaire
readings. Thus, if the fiber sample 18 has been weighed prior to
testing, the volume of the micronaire chamber 28 can be set by
bringing the forward plunger 26 and the rear plunger 30 relatively
toward each other to form a volume that is based on the weight of
the fiber sample 18 and an assumed density of the fiber sample
18.
[0045] If the fiber sample 18 has not been weighed prior to taking
the readings, or if the weight of the fiber sample 18 is otherwise
not to be used to determine the desired degree of compaction, then
the desired degree of compaction can be set by turning on the air
flow 32, and reducing the distance between the forward plunger 26
and the rear plunger 30 in a controlled manner, preferably such as
at a constant velocity. This can be accomplished with stepper
motors that drive one or both of the forward plunger 26 and the
rear plunger 30. Various elements of the air flow properties of the
air flow 32 are then monitored, which measured properties are then
used to determine the desired micronaire chamber 28 length.
Properties of the air flow 32 such as the volumetric flow and the
pressure of the air flow 32/34 are generally referred to as air
flow properties.
[0046] For example, the volumetric flow of the air flow 32 as
delivered at a constant inlet pressure can be measured, and when
the flow rate falls to a desired value, then the relative movement
of the plungers 26 and 30 is stopped. Alternately, the air flow 32
is initiated, and as the degree of compaction increases the air
flow resistance through the compacting fiber sample 18, the air
flow decreases and the pressure increases. Either the reduction in
the air flow or the increase in the pressure can be measured, and
the plunger movement can be stopped when a desired set point is
attained. In yet another alternate embodiment, a constant
volumetric flow of the air flow 32 can be initiated, while the
pressure required to produce the constant volumetric flow is
measured. When the pressure required to produce the constant
volumetric flow rises to a determined level, then the relative
movement of the plungers 26 and 30 is stopped.
[0047] These air flow properties as monitored provide an indication
of the degree of resistance to the air flow 32/34 through the
compacted fiber sample 18, which in turn provides an indication of
the degree of compaction of the fiber sample 18. At this point the
distance between the plungers 26 and 30 is determined, so that the
volume of the micronaire chamber 28 is known. The distance between
the plungers 26 and 30 can be directly measured, sensed along the
length of the micronaire chamber 28, or determined by tracking the
progress of the stepper motors that drive one or both of the
plungers 26 and 30.
[0048] The volume of the micronaire chamber 28 when a desired
degree of compaction of the fiber sample 18 has been attained can
also be used to estimate the weight of the fiber sample 18 within
the micronaire chamber 28. In some embodiments this estimated
weight of the fiber sample 18 is sufficient. However, if more
accurate micronaire values are desired, then the fiber sample 18 is
preferably weighed at some point before, during, or after the
measurement process.
[0049] The micronaire chamber 28 preferably has an operable length
of up to about six inches in which micronaire testing can be
performed on a compacted fiber sample 18, so as to accommodate a
wide range of fiber sample 18 weights. In this manner, the means by
which the loader 12 is loaded with the fiber sample 18 does not
need to be too sensitive in regard to the amount of the fiber
sample 18 that is so loaded. Preferably the diameter of the bore of
the micronaire chamber 28 is selected so that the length specified
above can hold between about one and about ten grams of a cotton
fiber sample 18.
[0050] The foregoing description of preferred embodiments for this
invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form disclosed. Obvious modifications or
variations are possible in light of the above teachings. The
embodiments are chosen and described in an effort to provide the
best illustrations of the principles of the invention and its
practical application, and to thereby enable one of ordinary skill
in the art to utilize the invention in various embodiments and with
various modifications as are suited to the particular use
contemplated. All such modifications and variations are within the
scope of the invention as determined by the appended claims when
interpreted in accordance with the breadth to which they are
fairly, legally, and equitably entitled.
* * * * *