Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF THE INVENTION
[0001] The present invention relates generally to equipment
and methods used with optical particle counters for determining
the size and concentration of particles of different sizes
contained within liquid samples, and more particularly to a
system and method for the automated dilution and delivery of a
plurality of liquid samples in a batch process to such optical
particle counters.
BACKGROUND OF THE INVENTION
[0002] It is common to quantitatively measure the size and
concentration of particulate contaminates in liquids, such as
new and used oils, in order to determine various characteristics
of the liquids. In samples of used oil, for instance, there are
both "hard particles" that are targeted for measurement in terms
of size and concentration, and similarly-sized "soft particles"
that inhibit the accurate measurement of the hard particles.
The presence of soft particles in a liquid sample is known to
significantly elevate particle counts to the point where their
presence compromises the validity of the count data obtained.
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It has been found, however, that the addition of a suitable
diluent to oil samples, can substantially eliminate the
interference of soft particles in obtaining accurate hard
particle count data.
[0003] Hard particles in oil include without limitation, dirt
and metal fragments, which have a serious impact on the life of
equipment by accelerating wear and erosion. Such hard particles
originate from a variety of sources, including generation from
within an operating fluid system, ingress into the operating
fluid system, or contamination that may occur during the storage
and handling of new oils. Typically, "soft particles" include
certain additives or additive by-products that are semi-
insoluble or insoluble in oil, and other similar materials that
are not known to directly increase wear and erosion within an
operating system, such as, for example, air bubbles and water
bubbles.
[0004] The measurement of such contaminants is particularly
important in order to identify the potential problems with
samples of new or used oils, to determine the characteristics of
various types of new or used oils, and also to determine whether
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engines and/or machinery are introducing metal particles into
used oil. More particularly, particle count results can be used
to aid in assessing the capability of the filtration system
responsible for cleaning oil or other fluid, determining if off-
line recirculating filtration is needed to clean up the fluid
system, or aiding in the decision of whether or not a fluid
change is required. An
abnormal particle count may trigger
concerns of these possibilities, which can be confirmed by
additional testing.
[0005]
Fundamentally, in order to permit the calculation of
useful and relevant data related to particles found in fluids,
such as oil, the quantity of various sizes of contaminants needs
to be determined. It is well known that in order to be useful,
such measurement requires quantitative guidelines in order to
meaningfully present the results.
Accordingly, various
standards are used for testing and reporting fluid cleanliness.
Two such standards include the SAE Aerospace Standard (AS) and
the ISO Code System. It has been found useful to group particle
sizes into coded ranges in order to permit ready handling and
manipulation of the data. The following table illustrates one
such standard of measurement as per the SAE Aerospace Standard
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(AS) system, with the codes for each range given in the left-
most column.
Cleanliness Classes for Differential Particle Counts (particles/100 ml) _
Size ,6 m (c) to 14um(c) to 21um(c) to 381.un(c)t9 ,
Code 141.trn(c) , 21prn(c) 381.un(c) - 7011rnfr) > 70pm(c) 1
00 126 22 4 1 0
0 250 44 8 2 0
1 500 , 89 16 3 1
2 1000 178 32 6 1
3 2000 356 63 11 2
4 4000 712 126 22 4
8000 1425 253 45 8
6 16000 2850 506 90 16
7 32000 5700 1012 180 32
8 64000 11400 2025 360 64
, 9 128000 22800 4050 720 128
256000 45600 , 8100 1440 256
11 512000 91200 16200 2880 512
12 1024000 182400 32400 5760 1024
[0 0 0 6 ] It is
well known to use automated optical particle
counters to quantitatively measure the size and concentration of
particulate contaminants in samples of fluids, such as new and
used oil.
Commonly, such optical particle counters perform
analysis based on the light extinction principle, using a laser
beam passing through a liquid sample. Such optical particle
counters are capable of recording the size and number of
particles as they pass across a detector, and such equipment
typically includes a sampling apparatus that automatically
delivers a pre-determined volume of liquid specimen at a
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controlled flow rate to the optical sensing cell of the optical
particle counter.
Examples of prior art optical particle
counters are taught in, amongst others, US Patent No. 5,426,501
(Hokanson et al.) issued June 20, 1995, and US Patent No.
5,172,004 (Furuya) issued December 15, 1992.
Indeed, tests
performed by such automated optical particle counters are
considered by many to be the single most important test for oil
analysis.
[0007] There
are various well-known problems associated with
the use of optical particle counters to test liquid samples,
especially samples of oil. One of the two most fundamental
problems is that of particle co-incidence.
Particle co-
incidence occurs when more than one particle is present in the
optical sensing cell of the optical particle counter at the same
time and a "large" particle is falsely detected rather than two
(or more) smaller ones. It is
well known that particle co-
incidence causes inaccurate counting of the "hard particles" due
to the presence of other type of particles, such as the "soft
particles" in the liquid sample. Soft
particles cause false
high counts of particles in their size category, thus yielding
false counts and an over-estimation of contamination levels
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across all sizes. Dilution of samples with a suitable diluent
can reduce the probability of particle co-incidence.
[0008]
Particle co-incidence can also occur due to the
existence of air bubbles in the oil, thereby causing false
positive readings.
Bubbles can be caused by overly vigorous
mixing or agitation of a liquid sample, which mixing may be
necessary as part of the test procedure. Further, suspended or
free water in the oil will generally be counted as particles.
[0009]
Another fundamental problem associated with the use of
optical particle counters to test liquid samples is that of the
proper flow of high viscosity liquid samples. The forces
required in order to develop the necessary pressure to rapidly
achieve the required flow rate of the liquid samples through the
optical sensing cell becomes quite significant, and even
prohibitive. For
this reason, it is extremely difficult to
properly and accurately test high viscosity liquid samples in an
optical particle counter without sample dilution using a
suitable diluent.
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[00010] In spite of the above stated advantages of using
diluted oil samples for testing with optical particle counters,
the vast majority of such testing is still carried out on
undiluted samples where the oil sample to be tested is taken
directly from a sample bottle without dilution. In such cases,
a mechanically controlled syringe is typically used to draw up a
measured volume of the liquid sample and inject it directly into
the inlet port of the optical sensing cell of the optical
particle counter. Alternatively, a sampling tube connected to
the optical sensing cell inlet is lowered into the sample
bottle. Pressure is used to force the liquid sample through the
optical sensing cell of the optical particle counter. Samples
are typically processed one by one (i.e., not in a batch
process), with the optical sensing cell and feeding tubes being
cleaned with solvent between tested samples.
[00011] Where
liquid sample to be tested by optical particle
counting are to be diluted prior to such testing in the prior
art, it is common to manually measure and mix known quantities
of the liquid sample and of a suitable diluent prior to testing.
More specifically, a laboratory pipette is often used to
manually draw a quantity of liquid from each sample bottle, as
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measured against volume markings on the pipette, and to inject
this drawn quantity of liquid sample from the pipette into a
sample container. This process is then repeated by pipette for
adding a measured volume of a suitable diluent to the sample
container. The two volumes are then summed for purposes of use
in any subsequent calculations required to convert raw particle
counts taken from a sample into standardized volumetric particle
counts.
[00012]
Although manual pipetting is accurate, it has a number
of significant drawbacks associated with it, particularly where
carried out repetitively for a high number of liquid samples to
be subsequently presented for testing by an optical particle
counter. These problems include, without limitation: i)
pipetting is labour intensive (i.e., time consuming) for the
operator carrying out the procedure; ii) pipetting is tedious
for the operator carrying out the procedure; iii) the
preparation of test samples cannot be performed outside of
normal laboratory operation hours without special (and typically
more expensive) arrangements being made to staff the test
facility with appropriate laboratory personnel; and, iv)
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operators carrying out the pipetting procedure for large numbers
of test samples are susceptible to repetitive strain injuries.
[00013] In order to improve and standardize methods for
optical particle counting utilizing diluted liquid samples, ASTM
International of West Conshohocken, PA, USA has developed and
published a test protocol known as ASTM-D7647 and entitled "Test
Method for Automatic Particle Counting of Lubricating and
Hydraulic Fluids Using Dilution Techniques to Eliminate the
Contribution of Water and Interfering Soft Particles by Light
Extinction". ASTM-
D7647 prescribes a standardized testing
methodology that requires the use of a diluent to dilute the
original samples to specified ratios of oil to diluent, prior to
optical particle counting readings taking place. It has been
found that the ASTM-D7647 test protocol notably addresses the
particle count inaccuracy issues caused by particle coincidence
and soft particles (as discussed above), especially where high
viscosity liquids are being tested. Accordingly, the erroneous
contribution of soft particles to the particle size cumulative
count is substantially negated by the ASTM-D7647 methodology.
The quality of particle count data is significantly improved on
many samples as the effects of known interference are removed.
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The present invention discloses and claims, in its simplest non-
limiting terms, a system for the automatic dilution and delivery
of a plurality of liquid test samples to an optical particle
counter for batch testing of diluted liquid samples according to
ASTM-D7647 in a more accurate and efficient manner than has been
possible with prior art sample handling equipment and
methodologies.
[00014] In
spite of the fact that ASTM-D7647 test protocol
provides significantly more accurate automated optical particle
counts than earlier testing methods, it has not gained
widespread commercial acceptance. This
lack of widespread
commercial acceptance is thought in large part to stem from the
fact that while the injection of the test sample into the
optical sensing cell and the reading of particle counts by the
optical sensing cell may be substantially automated through the
use of existing equipment, the preparation and presentation of
the test samples, including the addition of the aforesaid
diluent (by prior art manual pipetting techniques), has not been
significantly automated to date, and remains extremely labour
intensive. In other words, the testing of diluted oil samples
using the ASTM-D7647 protocol is presently known to be used only
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with manual sample presentation procedures, which include
pipetting, as aforesaid, with all of the attendant problems and
difficulties previously mentioned. As such, while ASTM-D7647 is
able to obtain improved particle count results over earlier
testing methodologies which do not involve the addition of a
diluent to the original sample volume to be tested, the prior
art drawbacks associated with pipetting, represent an ongoing
limitation to its widespread commercial acceptance, particularly
in light of the fact that the number of pipetting operations per
sample tested has necessarily been doubled over prior
methodologies not utilizing sample dilution.
[00015] Apart from manual pipetting of samples and diluent as
discussed above, there is presently no known apparatus, system,
or method for reliably automating the dilution and delivery of
liquid samples of oils and hydraulic fluids to an optical
particle counter, in accordance with the ASTM-D7647 test
protocol.
[00016] It is therefore an object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
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samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter in compliance
with the ASTM-D7647 testing protocol.
[00017] It is a further object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter in a manner
that eliminates the need for manual pipetting of the liquid
samples or of any diluents added to such liquid samples before
such testing.
[00018] It is a further object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, wherein
presentation of such mixtures for automated testing is less
labour-intensive than with known prior art equipment and methods
used for this purpose.
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[00019] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, wherein The
system permits for much more prompt and uniform presentation of
such mixtures for testing on a batch process basis.
[00020] It is still an object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, wherein The
system precludes the operator performing the preparation of such
mixtures from becoming unduly fatigued or from incurring
repetitive strain injuries.
[00021] It is also an object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, wherein The
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system permits comparable testing accuracy to prior art manual
dilution methods that use a pipette.
(00022] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, which
apparatus permits an accurate automated determination of the
volume of the liquid sample and of any diluent required to be
added to said sample in order to provide for automated filling
of each said test container to a standard test volume prior to
commencement of said automated testing.
(00023] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, which
apparatus permits automated dilution of the liquid samples to be
tested, especially new and used oils, in the higher viscosity
ranges.
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[00024] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, the
construction of which apparatus is relatively simple, compact,
and economical.
[00025] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, which system
saves the time and expense of manual sample presentation methods
which make uses of pipetting, and which presents the mixtures in
an ordered array, so as to allow automated testing of the
presented liquid samples without the need for additional manual
manipulation or supervision of the mixtures during said
automated testing, thereby permitting such testing to run
outside of normal laboratory operational hours.
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[00026] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, which system
maximizes the effective capacity of operators by freeing them
from the need for manual pipetting of liquid samples.
[00027] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, which
apparatus precludes operators from experiencing repetitive
strain injuries by reason of the elimination of pipetting tasks
associated with such presentation in the prior art.
[00028] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, which system
permits the dilution and delivery of a plurality of mixtures of
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diluent and liquid samples contained in congruent sample
containers to an optical particle counter, in accordance with
the ASTM-D7647 test protocol.
[00029] It is yet another object of the present invention to
provide an improved system for reliably automating the dilution
and delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter, which system
facilitates and promotes the adoption of the ASTM-D7647 test
method on a more widespread commercial scale.
SUMMARY OF THE INVENTION
[00030] In accordance with one aspect of the present invention
there is disclosed herein a novel system for the automated
dilution and delivery of a plurality of mixtures of diluent and
liquid samples respectively disposed in an equal plurality of
congruent sample containers to an optical particle counter, the
congruent sample containers having an upwardly facing open
mouth. The system comprises a container positioning member for
receiving and retaining the congruent sample containers in an
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array with a respective unknown volume of liquid sample having
been poured into each sample container, wherein the unknown
volume of each liquid sample is less than a pre-determined
threshold volume that is less than the total volume of the
respective sample container. An
automated diluent pumping
mechanism, having a diluent ingress port in fluid communication
with a diluent source and a diluent egress port, is positionable
in programmed sequence over the open mouth of each of the
congruent sample containers retained in the array, so as to be
able to draw a respective volume of a suitable diluent from the
diluent source and to introduce the drawn volume of the diluent
though the open mouth of each sample container for mixing with
the respective unknown volume of the liquid sample already
placed within each sample container, to together form a mixture
of the liquid sample and diluent, wherein the volume of the
mixture is substantially equal to the pre-determined threshold
volume. There
is also provided a mixer for agitating the
mixture of liquid sample and diluent in the sample containers.
Further, an automated mixture pumping mechanism is provided,
with said mechanism having a mixture ingress port positionable
in the programmed sequence over the mouth of each of the
congruent sample containers retained in the array, so as to be
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in fluid communication with the mixture of liquid sample and
diluent in each sample container, and a mixture egress port in
fluid communication with the optical particle counter, for
sequentially drawing a respective volume of mixture of diluent
and liquid sample from the sample containers and for delivering
the respective drawn volume of mixture of the liquid sample and
the diluent to the optical particle counter.
[00031] In accordance with another aspect of the present
invention, the system further comprises an ultrasonic measuring
device having an ultrasonic transducer and an ultrasonic sensor,
for measuring the vertical position of the top surface of the
liquid sample in each selected sample container with respect to
said ultrasonic 'measuring device.
[00032] In accordance with a further aspect of the present
invention, the system further comprises a computer/CPU that is
connected in data communicating relation to said ultrasonic
measuring device and that is programmed to calculate an accurate
height measurement of the top surface of the liquid sample in
the selected sample container with respect to an upwardly
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directed planar reference surface, using the measurement of the
vertical position of the top surface of the liquid sample.
[00033] In accordance with a still further aspect of the
present invention there is disclosed herein a method of
automatic dilution and delivery of a plurality of mixtures of
diluent and liquid samples respectively disposed in an equal
plurality of congruent sample containers to an optical particle
counter, the congruent sample containers having an upwardly
facing open mouth, the method comprising the steps of: (a)
receiving and retaining a plurality of congruent sample
containers in an array in a container positioning member on a
upwardly directed planar reference surface; (b) placing an
unknown volume of the liquid sample into each sample container,
wherein the unknown volume of each liquid sample is less than a
pre-determined threshold volume that is less than the total
volume of the respective sample container; (c) drawing a
respective volume of a suitable diluent from a diluent source;
(d) introducing the drawn volume of the diluent though the open
mouth of each sample container for mixing with the respective
unknown volume of the liquid sample placed within each sample
container to together form a mixture of the liquid sample and
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diluent, wherein the volume of the mixture is substantially
equal to the pre-determined threshold volume; (e) agitating the
mixture of liquid sample and diluent in the sample containers;
and, (f) sequentially drawing a respective volume of mixture of
liquid sample and diluent from the sample containers; and (g)
delivering the respective drawn volume of mixture of the liquid
sample and the diluent to the optical particle counter.
[00034] In
accordance with another aspect of the present
invention, the method further comprises the step of, after step
(b),above, but before step(c), above:
(b2) mechanically moving a measurement mechanism into place
over said unknown volume of liquid in said selected sample
container; and,
(b3) electronically measuring the vertical position of the
top surface of the liquid sample in each selected sample
container with respect to said measurement device.
[00035] These and other objects, advantages, features and
characteristics of the present invention, as well as methods of
operation and functions of the related elements of the structure
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and method, together with the combination of parts and economies
of manufacture and process, will become more apparent upon
consideration of the following detailed description and the
appended claims with reference to the accompanying drawings, the
latter of which is briefly described herein below.
BRIEF DESCRIPTION OF THE DRAWINGS
[00036] The novel features which are believed to be
characteristic of the method and apparatus for dilution and
delivery of a plurality of mixtures of diluent and liquid
samples respectively disposed in an equal plurality of congruent
sample containers to an optical particle counter according to
the present invention, as to its structure, organization, use
and method of operation, together with further objectives and
advantages thereof, will be better understood from the following
drawings in which a presently preferred embodiment of the
invention will now be illustrated by way of example. It is
expressly understood, however, that the drawings are for the
purpose of illustration and description only, and are not
intended as a definition of the limits of the invention. In the
accompanying drawings:
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[00037] Figure 1 is a perspective view illustrating an
embodiment of a system according to the invention shown in use
with an optical particle counter and with the container
positioning member removed from its in-use sampling
configuration;
[00038] Figure 2 is a top plan view of the base member of The
system of Figure 1, with the container positioning member
completely removed from view;
[00039] Figure 3A is a cut-away perspective view of a portion
of the base member of Figure 2, showing one of the gimbal mounts
there beneath;
[00040] Figure 3B is an exploded cut-away perspective view of
Figure 3A;
[00041] Figure 4 is a top plan view of the container
positioning member of Figure 1, with all of the congruent sample
containers removed therefrom;
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[00042] Figure 5 is an enlarged side elevational view of an
empty sample container;
[00043] Figure 6 is an enlarged side elevational view of the
sample container of Figure 5, but with a volume of liquid sample
therein;
[00044] Figure 7 is a top plan view similar to Figure 4, but
with the congruent sample containers of Figure 1 in place
therein;
[00045] Figure 8 is a front elevational view of The system
shown in Figure 1, with the container positioning member being
removed from its in-use sampling configuration;
[00046] Figure 9 is a front elevational view similar to Figure
8, but with the container positioning member shown in its in-use
sampling configuration;
[00047] Figure 10 is a sectional front elevational view taken
along section line 10-10 of Figure 8;
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[00048] Figure 11 is a sectional front elevational view taken
along section line 11-11 of Figure 9;
[00049] Figure 12 is an enlarged scale front elevational view
of a portion of The system illustrated in Figure 1, the
illustrated portion including a sampling head with various
devices mounted thereon;
[00050] Figure 13 is a front elevational view similar to
Figure 12, showing the sampling head with various devices
mounted thereon and showing a diluent reservoir, a diluent
syringe, and a delivery and uptake tube apparatus in use;
[00051] Figure 14 is a diagrammatic sketch showing other
components of The system of Figure 1;
[00052] Figure 15 is an enlarged side elevational view of one
of the components of Figure 14, being a delivery and uptake tube
apparatus;
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[00053] Figure 16 is a front elevational view similar to
Figure 9, showing an unknown volume of liquid sample being
poured into each congruent sample container;
[00054] Figure 17 is a front elevational view similar to
Figure 16, showing a pre-determined threshold volume of a
mixture of liquid sample and diluent being the same volume for
each sample container;
[00055] Figure 18 is a front elevational view similar to
Figure 13, showing a respective volume of a suitable diluent
being drawn from a diluent source;
[00056] Figure 19 is a front elevational view similar to
Figure 18, showing a drawn volume of diluent being introduced
into a congruent sample container though its open mouth;
[00057] Figure 20 is a front elevational view similar to
Figure 19, showing the mixture of liquid sample and diluent in
the congruent sample container being agitated by a mixer;
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[00058] Figure 21 is a diagrammatic sketch similar to Figure
14, showing a respective volume of mixture of liquid sample and
diluent being sequentially drawn from a congruent sample
container; and,
[00059] Figure 22 is a diagrammatic sketch similar to Figure
21, showing a respective drawn volume of mixture of the diluent
and liquid sample the being delivered to an optical particle
counter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[00060] Reference will now be made to Figures 1 through 22,
which show an exemplary embodiment of a system, as indicated by
the general reference numeral 120, according to the present
invention, for the automated dilution and delivery of a
plurality of mixtures 107 of diluent 103 and liquid samples 122
respectively disposed in an equal plurality of congruent sample
containers 130 to an optical particle counter, as indicated by
the general reference numeral 110. In overview, the system 120
claimed herein comprises, in broad, non-limiting terms, four
main components, namely a container positioning member 150, an
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automated diluent pumping mechanism 108, an automated mixer 116,
and an automated mixture pumping mechanism 106, as will be
described in more detail below.
[00061] The container positioning member 150 is manually
movable by an operator from an operative in-use sampling
configuration (see Figures 9 and 11) wherein it rests atop the
base member 126 with the base 132 of each one of a plurality of
congruent sample containers 130 resting on an upwardly directed
reference surface 170, to a plurality of configurations (see for
example Figures 1 and 8) wherein the container positioning
member 150 is removed from such resting contact with the
reference surface 170, as will be described below in
considerably more detail. In
the operative in-use sampling
configuration, the congruent sample containers 130 are retained
in an array for sequential access by the system 120, as
described more fully below.
[00062] As
can be best seen in Figures 13 and 14, the system
120 interacts with a prior art automated optical particle
counter 110, and includes a computer/CPU 112 connected in data
transfer relation to the automated optical particle counter 110
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(which includes an optical sensing cell 111), a sampling head
114, a delivery and uptake tube apparatus 115, the slow speed
mixer 116, a small and accurate ultrasonic measuring device 117
having an ultrasonic transducer 117t and an ultrasonic sensor
117s, a mounting mechanism 118, a mixture syringe 106, a diluent
syringe 108, and a diluent reservoir 109, which will typically,
as shown in the figures, be remotely located from the other
components shown in Figure 1. In
the exemplary embodiment
illustrated, the mixture syringe 106, the diluent syringe 108,
the optical particle counter 110, which includes the optical
sensing cell 111, are preferably located within, or mounted on,
the housing 113. They may, however, also be located remotely
from the housing 113, with the use of suitable tubing and
cabling used to extend their operative connections, as per
design choice.
[00063] The sampling head 114 has mounted on it for movement
therewith, and a delivery and uptake tube apparatus 115, a slow
speed mixer 116 in horizontally movable relation on a
horizontally oriented "X-Y" reference frame 127, for controlled
two-dimensional movement in a horizontal "X-Y" coordinate grid
over the container positioning member 150, the sample containers
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130, and the reference surface 170 when The system 120 of the
present invention is in its in-use sampling configuration for
use with the automated optical particle counter 110 as described
herein.
[00064] More specifically, the system 120 provides for the
automated dilution and delivery of a plurality of mixtures 107
of diluent 103 and liquid samples 122 respectively disposed in
an equal plurality of congruent sample containers 130 to
sampling cell 111 of the optical particle counter 110. The
congruent sample containers 130 each have an upwardly facing
open mouth 142 through which liquids may enter the exit the
congruent sample containers 130. The system also comprises a
container positioning member 150 for receiving and retaining the
congruent sample containers 130 in an array. The
array is
preferably regularly and evenly spaced, and is based on a
perpendicular "X-Y" reference system, or in other words, a
quadrilateral array. Other patterns or arrangement of arrays
are also acceptable and within the scope of the present
invention.
- 30 -
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[00065] A respective unknown volume of liquid sample 122 has
been poured into each sample container 130, as can be best seen
in Figures 16 and 17. Typically, the unknown volume of liquid
sample 122 is manually poured by an operator (without the need
of a pipette) from a sample bottle 101, as seen in Figure 16.
Typically each sample bottle 101 will contain a unique liquid
sample 122 originating from a unique identified source, which
source information will be tracked throughout the testing
process as per usual laboratory procedures. The unknown volume
of each liquid sample 122 may be approximated by visual
estimation of the operator with respect to indicia 131 marked on
the sidewall of each of the sample containers 130.
[00066] The unknown volume of each liquid sample 122 must
essentially be less than a pre-determined threshold volume
determined to be a useful overall volume to use with the optical
particle counter 110. As can be readily understood, the pre-
determined threshold volume is necessarily also less than the
total volume of the respective sample container 130.
[00067] The system 120 also comprises an automated diluent
pumping mechanism 108 having a diluent ingress port 108ip, and a
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diluent egress port 115e. More
specifically, the diluent
pumping mechanism 108 preferably comprises a diluent syringe 108
having a mouth 108m, and a valve 108a connected in leak-proof
relation to the diluent syringe 108 at the mouth 108m. The
valve 108a has a valve inlet 108vi, a valve outlet 108vo, and a
syringe opening 108b. The
valve inlet 108vi is in fluid
communication with the diluent ingress port 1081p and the valve
outlet 108vo in fluid communication with the diluent egress port
115e. The syringe opening 108b connects the valve inlet 108vi,
the valve outlet 108vo, and the mouth 108m of the diluent
syringe 108 in fluid communication with each other.
[00068] The diluent ingress port 108ip is in fluid
communication with a diluent source 109 shown in Figures 13, 18
and 19, as diluent reservoir 109. In the preferred embodiment
as illustrated, the diluent egress port comprises an outlet 115e
of an outer diluent tube 115, that is part of the delivery and
uptake tube apparatus 115. The
diluent egress port 115e is
positionable in programmed sequence, as controlled by the
computer/CPU 112, over the open mouth 142 of each of the
congruent sample containers 130 retained in the array.
- 32 -
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[00069] The
automated diluent pumping mechanism 108 is adapted
as described for drawing a respective volume of a suitable
diluent from the diluent source 109, and for introducing the
drawn volume of the diluent 107 though the open mouth 142 of
each sample container 130 for mixing with the respective unknown
volume of the liquid sample 122 placed within each sample
container 130 to together form a mixture 107 of the diluent 107
and liquid sample 122 for testing by the optical particle
counter 110. The
volume of the mixture 107 in each sample
container 130 should be substantially equal to the pre-
determined threshold volume.
[00070] The
system 120 further comprises an automated mixture
pumping mechanism that preferably comprises an electrical motor
driven mixture syringe 106 having a mixture ingress port 115i
(on uptake tube apparatus - see Figure 15), and a mixture egress
port 106ep. More
specifically, the mixture pumping mechanism
preferably comprises the mixture syringe 106 having a mouth
106m, and a valve 106a connected in leak-proof relation to the
mixture syringe 106 at the mouth 106m. The valve 106a has a
valve inlet 106vi, a valve outlet 106vo, a syringe opening 106b
and a central chamber 106c. The valve inlet 106vi is in fluid
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communication with the mixture ingress port 115i, and the valve
outlet 106vo is in fluid communication with the mixture egress
port 106ep. The central chamber 106c connects the valve inlet
106vi, the valve outlet 106vo, and the syringe opening 106b in
fluid communication with each other. The syringe opening 106b
and the mouth 106m of the mixture syringe 106 connect the valve
106a and the syringe 106 in fluid communication one with the
other.
[00071] The mixture egress port 106ep is also in fluid
communication with the optical sensing cell 111 of the optical
particle counter 110, as can be best seen in Figures 14, 21 and
22. In
the preferred embodiment illustrated, the mixture
ingress port 1151 comprises an inlet 115i disposed at the bottom
end 115h of the uptake tube apparatus, as best seen in Figure
15. The mixture ingress port 115i is positionable in programmed
sequence over the open mouth 142 of each of the congruent sample
containers 130 retained in the array so as to be in fluid
communication with the mixture 107 of diluent 103 and liquid
sample 122 in each congruent sample container 130.
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[00072] As
described, the automated mixture pumping mechanism
is for sequentially drawing a respective volume of mixture 107
of diluent 103 and liquid sample 122 from the sample containers
130 and for delivering the respective drawn volume of mixture
107 of diluent 103 and liquid sample 122 to the optical particle
counter 110.
[00073] The
system 120 further comprises the computer/CPU 112,
that is connected in data communicating relation to the
ultrasonic measuring device 117. Any
suitable type of
computer/CPU 112 could be used, from a portable dedicated
handheld unit, through a laptop computer, or a desktop computer,
through a mainframe computer. The
terms "computer", "central
processing unit" and "computer/CPU" are used interchangeably in
this specification and the claims appended hereto, as will be
understood by those skilled in the art. The computer/CPU 112 is
programmed, inter alia, to electronically measure the vertical
position of the top surface 122t of the liquid sample 122 in
each selected sample container 130 with respect to the
measurement device, namely the ultrasonic measuring device 117.
The computer/CPU 112 is also programmed to electronically
calculate an accurate height measurement of the top surface 122t
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of the liquid sample 122 in the selected sample container 130
with respect to an upwardly directed planar reference surface
170, using the measurement of the vertical position of the top
surface 122t of the liquid sample 122. The
accurate height
measurement of the top surface 122t of the liquid sample 122 in
the selected sample container 130 with respect to an upwardly
directed planar reference surface 170 is calculated by means of
determining the vertical difference between the vertical
position of the top surface 122t of the liquid sample 122 and
the vertical position of the upwardly directed planar reference
surface 170.
[00074] The computer/CPU 112 is also programmed to
electronically calculate the unknown volume of the liquid sample
122 in the selected sample container 130 using the aforesaid
accurate height measurement combined with the known geometry of
the congruent sample containers 130. The
congruent sample
containers 130 as illustrated are frustum shaped, which makes
the calculation of the internal volume of the containers at any
particular height relatively straight forward, as would be well
known by one skilled in the art.
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[00075] The computer/CPU 112 is further programmed to
electronically calculate the volume of diluent to add into the
selected sample container 130 necessary to obtain the pre-
determined threshold volume of the mixture 107, based on the
difference between the volume of the liquid sample 122 in the
selected sample container 130 and the pre-determined threshold
volume. The
computer/CPU 112 is further programmed to
electronically calculate the volume of diluent to add into the
selected sample container 130 to obtain the pre-determined
threshold volume of the mixture 107, as aforesaid, based on the
viscosity of the liquid sample 122.
Alternatively, the
computer/CPU 112 is programmed to electronically calculate the
volume of the liquid sample 122 in the selected sample container
130 based on a calibration graph of sample height versus sample
volume.
Further, the computer/CPU 112 is further programmed
such that the pre-determined threshold volume of the mixture 107
is substantially the same volume for each sample container 130.
(00076] If desired, a further step can be included. More
specifically, the computer/CPU 112 can be further programmed to
electronically calculate the dilution ratio of the unknown
volume of diluent 103 and liquid sample 122 in the sample
- 37 -
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container 130. If the dilution ratio of the unknown volume of
liquid to the diluent is between about 1:0 and 1:9, the
subsequent step of agitating the mixture 107 of the diluent 103
and liquid sample 122 can also be performed.
[00077] The computer/CPU 112 is further programmed to
electronically control the speed of the slow speed mixer 116.
The slow speed mixer 116 is for agitating the mixture 107 of the
diluent 103 and liquid sample 122 in the sample containers 130.
Controlling the speed of the mixer 116 is important in order to
accommodate various pre-determined threshold volumes, various
sizes of congruent sample containers 130, and also various
viscosities of liquid samples 122.
[00078] In order for the above described functions to be
performed, the sampling head 114, the delivery and uptake tube
apparatus 115, the slow speed mixer 116, and the small and
accurate ultrasonic measuring device 117 must be horizontally
and vertically movable over the horizontally oriented "X-Y"
reference frame 127. The sampling head 114, the delivery and
uptake tube apparatus 115, the slow speed mixer 116, and the
small and accurate ultrasonic measuring device 117 are
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preferably operatively mounted in horizontally and vertically
movable relation on the reference frame 127 by the mounting
mechanism 118. The
diluent ingress port 108ip, the diluent
egress port 115e and the mixer are mounted on the sampling head
114, that is itself mounted in vertically movable relation on
the horizontally oriented "X-Y" reference frame 127 by means of
a mounting mechanism 118.
[00079] Fundamentally, the horizontally oriented "X-Y"
reference frame 127 is for operatively mounting the diluent
egress port 115e, the mixture ingress port 115i and the mixer
116 in horizontally movable relation for controlled two-
dimensional movement in a horizontal "X-Y" coordinate grid over
the container positioning member 150.
Further, the "X-Y"
reference frame 127 carries the mounting mechanism 118, to which
the sampling head 114 is operatively mounted, for controlled
movement in a vertical "Z" direction with respect to the "X-Y"
reference frame 127 and the container positioning member 150.
The overall horizontal and vertical movement may also be
considered as three-dimensional movement in an "X-Y-Z" reference
frame.
- 39 -
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[00080] The
horizontally oriented "X-Y" reference frame 127
comprises a first horizontal track 127a and a second horizontal
track 127b oriented substantially perpendicularly one to the
other. The mounting mechanism 118 is mounted in horizontally
movable relation on the horizontally oriented "X-Y" reference
frame 127, and more specifically, mounted in horizontally
movable relation in a "Y"-direction on the first horizontal
track 127a. The first horizontal track 127a is mounted on the
second horizontal track 127b in horizontally movable relation in
an "X"-direction that is perpendicular to the "Y"-direction.
[00081] The system 120 further comprises an "X"-horizontal-
movement motor 127x for moving the first horizontal track 127a
in horizontally movable relation in the "X"-direction along the
second horizontal track 127b, a "Y"-horizontal-movement motor
127y for moving the mounting mechanism 118 in horizontally
movable relation in the "Y"-direction along the first horizontal
track 127a, and a "Z"-vertical-movement motor 127z for moving
the sampling head 114 in vertically movable relation in the "Z"-
direction along the mounting mechanism 118. The "X"-horizontal-
movement motor 127x, the "Y"-horizontal-movement motor 127y, and
the "Z"-horizontal-movement motor are each controlled by
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suitable software executed by the computer/CPU 112 and are
independently movable one with respect to the other.
[00082] The
delivery and uptake tube apparatus 115, which is
best shown in enlarged isolated format in Figure 15, is mounted
on the sampling head 114. As will be seen in the Figures, the
diluent ingress port 108ip and the diluent egress port 115e are
part of the delivery and uptake tube apparatus 115. In
the
preferred embodiment illustrated, the delivery and uptake tube
apparatus 115 comprises an outer diluent tube 115a and an inner
delivery tube 115f. The outer diluent tube 115a has a top end
115b and a bottom end 115c, with an inlet 115d disposed adjacent
the top end 115b and an outlet 115e comprising a plurality of
jets disposed adjacent the bottom end 115c. The inlet 115d is
connected in fluid communication to the diluent syringe 108
through the line indicated by arrow "G2" in Figure 13. The inner
delivery tube 115f has a top end 115g and a bottom end 115h,
with an inlet 1151 disposed adjacent the bottom end 115h and an
outlet 115j disposed adjacent the top end 115g. The outlet 115j
is connected in selective fluid communication to the input side
of the optical sensing cell 111 of the optical particle counter
110, as described more fully below.
- 41 -
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[00083] This double tube arrangement keeps separate the sample
mixture 107 and diluent 103 supply streams.
Accordingly,
diluent enters the outer diluent tube 115a near the top end 115b
through the inlet 115d and flows from the outer diluent tube
115a over the inner delivery tube 115f, and egresses from the
outer diluent tube 115a through the outlet 115e positioned at
the bottom end 115c.
Liquid sample 122 enters the inner
delivery tube 115f through the inlet 115i disposed at the bottom
end 115h and egresses the inner delivery tube 115f through the
outlet 115j disposed adjacent the top end 115g. The
inner
delivery tube 115f is slidably mounted within the outer diluent
tube 115a in fixed final relation thereto.
[00084] In conjunction with the system 120 of the present
invention, an automated optical particle counter 110 performs
automated particle counts of mixtures 107 of diluent 103 and
liquid samples 122 presented by the system 120 and contained
within the plurality of substantially congruent sample
containers 130. As an integral part of the process, the volume
of liquid sample 122 in each sample container 130 must be
determined with considerable accuracy in order to achieve an
accurate particle count. Further, the amount of diluent 103 to
- 42 -
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add to the unknown volume of liquid sample 122 must be
calculated accurately, and must be added accurately to the
liquid sample 122. It has been found that the system 120 of the
present invention produces a potential sample volume error of
less than 2%, which is well within acceptable tolerances for the
ASTM-D7647 test method, and which tolerance level has not been
achieved in the prior art, so far as automated liquid sample 122
dilution and presentation systems are concerned.
[00085] In
order to accurately perform volumetric calculations
of liquid sample 122 in the sample containers 130 received and
retained by the cup positioning member 150, the ultrasonic
measuring device 117 with its ultrasonic transducer 117t and its
ultrasonic sensor 117s is used. The ultrasonic measuring device
117 uses very small sensor (VSS) technology, and is used to
accurately measure the height of liquid in each of the congruent
sample containers 130 tested. The ultrasonic measuring device
117 is preferably incorporated into a plastic mounting member
119 mounted adjacent the bottom end 118a of the mounting
mechanism 118 that carries the moveable sampling head 114. Data
can be obtained from the ultrasonic sensor and is used by the
computer/CPU 112 to quickly and accurately calculate the volume
- 43 -
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of liquid sample 122, such as used oil, to be tested in each
congruent sample container 130 immediately before proceeding
with dilution of each liquid sample 122.
[00086] Generally speaking, for each congruent sample
container 130 containing a liquid sample 122, the measurement
mechanism, namely the transducer 117t and the sensor 117s of the
ultrasonic measuring device 117, is moved into place in a fixed
"X-Y" coordinate position directly over the unknown volume of
liquid sample 122 in the sample container 130. An ultrasonic
wave is emitted from the ultrasonic transducer 117t, and is
reflected from the surface of the liquid 122 in the sample
container 130. The reflected ultrasonic wave is received back at
the sensor 117s and the time difference between emission and
reflection is measured, and is used to determine the height of
the top surface 122t of the liquid 122. Once the height of the
top surface 122t of the liquid 122 in the congruent sample
container 130 is established in this manner, the volume of
liquid 122 in the sample container 130 can be determined from
the geometry of the sample container 130.
Thereafter, the
volume of diluent 103 that will be needed to dilute the liquid
sample 122 to a final volume for testing, can then be calculated
- 44 -
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by the computer/CPU 112 and automatically added to the liquid
sample 122 in the sample container 130. It has been found that
a suitable diluent is one such as a solvent comprising, for
example, 75% toluene and 25% Propan-2-ol.
[00087]
Reference will now be made to Figures 5 through 11,
which figures show the congruent sample containers 130 being
prepared and presented for batch testing according to the
present invention. Figure 5 shows an empty congruent sample
container 130 about to have an unknown volume of liquid sample
122 poured into it, and sequentially Figure 6 shows a sample
container 130 having about seventeen (17) milliliters of liquid
sample 122 having been manually poured by optical estimation by
a laboratory technician into it, =after the liquid sample 122 has
been sufficiently pre-mixed in the sample bottle 101 to evenly
distribute any contaminants.
Figures 7 through 11 show a
plurality of congruent sample containers 130 retained by the
container positioning member 150 being manipulated into place on
the reference surface 170. While a liquid sample 122 having a
volume of about seventeen (17) milliliters has been manually
poured into each of the congruent sample containers 130 by a
laboratory technician without pipetting, the exact volume is
- 45 -
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unimportant, so long as the volume is below the pre-determined
threshold volume of thirty (30) milliliters.
(00088] The main operational advantage of the present
invention, namely the system 120, is that it allows approximate
volumes of oil samples that are to be tested to be manually
poured by laboratory personnel directly into congruent sample
containers 130. This method of directly pouring the oil samples
into the congruent sample containers 130 is quick, simple, and
easy. Most importantly, it also eliminates the use of a pipette
for handling of the liquid samples 122 and of the diluent,
thereby ameliorating, or even entirely eliminating, the known
disadvantages associated with pipetting, as mentioned
previously, namely a high labour content and associated costs,
lack of availability of labour during off hours, slowness of the
process, and repetitive strain injuries to pipetting personnel.
(00089] Figure 7 is a top plan view of the container
positioning member 150 and a plurality of congruent sample
containers 130, and shows that the first two positions 130a and
130b may contain empty congruent sample containers 130, as they
may be used for storing diluent and for system cleanliness
- 46 -
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verifications. Diluent 103 from the reservoir 109 (see Figure
13) is delivered to the sample container 130a in position number
"one" (i.e., Column 1, Row 1 in Figure 7) and used to flush the
delivery tubing and the optical sensing cell 111 of the optical
particle counter 110 prior to diluent verification.
Further,
diluent 103 from the reservoir 109 is dispensed to the sample
container 130b in position number "two", (i.e., Column 1, Row 2
in Figure 7) for example, and twenty-five (25) milliliters of
this diluent aspirated to the mixture syringe 106.
(00090] In
order to determine the volume of liquid sample 122
in the sample container 130 being tested, and also to determine
the volume of diluent 103 that will be needed to dilute the
liquid sample 122 to a pre-determined threshold volume for
testing of, for example, thirty (30) milliliters, data from the
ultrasonic height sensor 117 in the sampling head 114 is
transferred to the computer/CPU 112. A batch file containing
the position of the cup positioning member 150 and other
information related to the liquid sample 122 in the congruent
sample containers 130 is stored on the computer/CPU 112
controlling the automated optical particle counter 110.
- 47 -
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[00091]
Depending on the viscosity and expected cleanliness of
the liquid sample 122, each liquid sample 122 is preferably
diluted before testing by means of the addition of a suitable
diluent (solvent) added to each sample container 130 such that
the volume of diluent 103 added is preferably between three (3)
milliliters (1:10 dilution) and fifteen (15) milliliters (1:1
dilution), assuming a thirty (30) milliliter sample container
130 is utilized. The diluent 103 and the liquid sample 122 must
then be agitated in order to fully mix the diluent 103 and the
liquid sample 122 to create the mixture 107. In
order to
accomplish this, the sampling head 114 moves under control of
the computer/CPU 112 down into the sample container 130 and the
slow speed mixer 116 is started. The required volume of diluent
103 is then added to the sample container 130 through the
diluent tube 115a to dilute the liquid sample 122, as previously
explained (see Figure 13). The
diluent 103 and the liquid
sample 122 are mixed under control of the computer/CPU 112 for a
specified time period to dissolve the diluent 103 and liquid
sample 122 and suspend the various particulates.
[00092] After
the mixing period expires, the mixture syringe
106 is programmed to draw a volume of approximately six (6)
- 48 -
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milliliters of mixture 107 from the sample container 130 through
the delivery uptake tube apparatus 115 and into the mixture
syringe 106. The
mixture syringe 106 is then programmed to
dispense the volume of six (6) milliliters to the optical
sensing cell 111 and to eject displaced air from the syringe
106, and to thereafter flush the optical sensing cell 111 with
about three (3) milliliters of a new mixture sample. A further
volume of approximately twenty-three (23) milliliters of new
mixture sample 107 is then aspirated to the mixture syringe 106.
The valve 106a is switched by the computer/CPU 112 to isolate
the inlet port 106b of the syringe 106. The mixture syringe 106
is further programmed to aspirate a small additional volume of
mixture 107 against the closed inlet port 106b in order to
create a partial vacuum in the syringe 106 and thereby degas the
mixture 107. After a specified degassing period, the mixture
syringe 106 is programmed to dispense the additional volume of
mixture 107 to the optical sensing cell 111 to restore near
normal pressure.
[00093] Once
the mixture 107 has been degassed as aforesaid,
the sample analysis takes place within the optical sensing cell
111 according to the know processes of such devices. Three
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separate tests as just described are preferably conducted
sequentially by the optical particle counter 110. In each of
the three tests, a five (5) milliliter samples of the mixed
diluent liquid sample is analyzed. The data set is tested for
ASTM D7647 validity and an average particle count and
distribution result is calculated by the computer/CPU 112. All
measured and calculated data is stored in a sample specific text
file in the computer/CPU 112 for subsequent processing time by
the operator.
Subsequent to each test, the mixture 107 is
expelled from the optical sensing cell 111 of the particle
counter 110, as indicated by arrow "L" in Figures 14, 21 and 22.
[00094] In the embodiment illustrated, the system, as
indicated by the general reference numeral 120, is used for the
automated dilution and delivery of a plurality of mixtures 107
of diluent 103 and liquid samples 122 respectively disposed in
an equal plurality of congruent sample containers 130 to an
optical particle counter 110. The congruent sample containers
130 are substantially identical to one another and are,
preferably, cup-like in shape (without a handle) and may, for
reasons of availability and economy, be the same as, or similar
to, the well known plastic pill containers used in hospitals and
- 50 -
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the like to dispense a dosage of pills or other medicine to
patients of such facilities. In any event, each container 130
has a base 132, and a continuous sidewall 134 that is preferably
annular in shape so that the rotational orientation of each
congruent sample container 130 during use is not relevant.
Preferably, but not essentially, the congruent sample containers
130 are each frustum shaped. As can be best seen in Figures 5,
6, 8 and 9, the continuous sidewall 134 of the congruent sample
containers 130 each has an inner wall surface 136 and an outer
wall surface 138, and extends upwardly from the base 132 to
terminating at a top end 140 to thereby define the upwardly
facing open mouth 142. There is also an engagement portion 144
of the outer wall surface 138 that is wider than the base 132
and closer to the mouth 142 than to the base 132. The
engagement portion 144 is dimensioned for engaging the container
positioning member 150, in one configuration (only) of the
container positioning member 150, as will be discussed
subsequently in greater detail.
[00095] Further, the container positioning member 150
comprises a horizontally extending main body portion 152. In
the preferred embodiment, as illustrated, the main body portion
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152 preferably, but not essentially, comprises an upper plate
154 and an optional lower plate 156, which may be connected
together in secure relation by peripheral side walls 157a and
peripheral end walls 157b and by a plurality of spacers 158.
The upper plate 154 and the lower plate 156 may be secured
together via the peripheral side walls 157a and peripheral end
walls 157b by threaded fasteners 157c. Further, the upper plate
154 and the lower plate may be secured together via the
plurality of spacers 158 by threaded fasteners 158c. There are
also preferably provided two horizontally outwardly projecting
end flanges 157d disposed one flange at each end of the main
body portion 152.
(00096] The
upper plate 154 and the lower plate 156 are each
preferably substantially planar and substantially parallel one
to the other. For the sake of strength and rigidity, the main
body portion 152 is made substantially from metal components
and, preferably from aluminium-based materials, or from
stainless steel-based materials.
Alternatively, the container
positioning member 150, and/or any of the components thereof,
may be made from any other suitably rigid and robust material.
- 52 -
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[00097] As
can best be seen in Figures 8 and 9, the main body
portion 152 of the container positioning member 150 comprises a
plurality of substantially vertically disposed container-
receiving sockets 160 formed in the main body portion 152.
Preferably, the substantially vertically disposed container-
receiving sockets 160 are arranged in an ordered array, or in
other words, a rectangular matrix pattern, in order to simplify
the positioning of the sampling head 114 during use of The
system 120.
Further, the substantially vertically disposed
container-receiving sockets 160 are substantially annular in
plan outline, in order to help control and minimize the vertical
and lateral movement of the congruent sample containers 130
during use.
[00098] Each
of the container-receiving sockets 160 preferably
has a top end 162 and a bottom end 164, and is open at the top
end 162 and the bottom end 164, in order to permit a sample
container 130 to extend therethrough. Each container-receiving
socket 160 is defined at the top end 162 by a container-
receiving rim portion 166. In the preferred embodiment
illustrated, each of the substantially vertically disposed
container-receiving sockets 160 comprises an upper container-
- 53 -
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receiving aperture 168 in the upper plate 154 and a lower
container-receiving aperture 169 in the lower plate 156 in axial
alignment with the upper container-receiving aperture 168 (best
seen in Figures 10 and 11).
[00099] The
container positioning member 150 further comprises
a plurality of feet 159 projecting downwardly from the main body
portion 152 at each of the two horizontally outwardly projecting
end flanges 157c. As can be best seen in Figures 8 and 9, each
of the feet 159 is secured in place on the bottom of the two
horizontally outwardly projecting end flanges 157c by a co-
operating threaded fastener 159a extending downwardly through
co-operating through passages (not specifically shown) in the
cylinders 159b disposed above the outwardly projecting end
flanges 157c and through apertures (not specifically shown) in
the horizontally outwardly projecting end flanges 157c, to each
threadingly engage one of the feet 159, to thereby secure the
feet 159 in a fixed vertical orientation as illustrated.
[000100] A corresponding plurality of co-operating foot-
locating recesses 124 (see Figures 1 and 2) may optionally be
formed in opposed side rails 126a of the base member 126
- 54 -
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adjacent to the reference surface 170, for receiving the feet
159 in stable indexed relation therein when the container
positioning member 150 is placed over the reference surface 170
in the operative in-use configuration (see Figures 4, 7, 9, and
11).
[000101] The base member 126, which structure may be generally
table-like, having parallel front and back rails 126b, 126b
rigidly connected to opposed side rails 126a, 126a, with the
space between all four rails being occupied by a horizontal base
plate 195 rigidly connected to the rails. All four rails 126a,
126a, 126b, 126b preferably stand proud of the horizontal base
plate 195, so as to define a cavity of quadrilateral plan
outline, in which cavity the reference surface 170 may be
located as shown. Ideally, but not necessarily, the reference
surface 170 is mounted so as to extend upwardly from within the
cavity to approximately the same height as the upper surfaces of
the four rails 126a, 126a, 126b, 126b. A set of four legs 126c
complete the table-like structure that is the base member 126.
The components of the base member 126 are preferably constructed
from the same general type of metal materials as is the
container positioning member 150.
- 55 -
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[000102] The base member 126 has a reference surface 170
mounted thereon for adjustment of its horizontal level.
Preferably, the reference surface 170 is planar, and may, as
shown, be constructed from a sheet of plate glass 172 which
presents its upper surface as the reference surface 170. It has
been determined by the inventor that a high quality precision
formed sheet of plate glass provides a reference surface 170
having a height variation of less than 0.025mm across its upper
surface, which is sufficiently flat for most testing discussed
herein at a reasonable cost, as compared to having a similarly
dimensioned reference surface constructed from plate metal, the
latter of which would typically require a costly machining
operation to achieve a similar degree of levelness (i.e.
flatness) across its upper surface.
[000103] The reference surface 170 may be mounted on the base
member 126 for adjustment of its horizontal level as aforesaid
by means of at least three gimbal mounts 190 (one of which is
illustrated in detail in Figures 3A and 3B), atop of which
gimbal mounts 190 the reference surface 170, specifically the
sheet of plate glass 172, sits. In the embodiment illustrated,
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four gimbal mounts 190 are positioned adjacent each of the four
corners of the reference surface 170 (see Figure 2). If
required, a fifth gimbal mount (not shown) may also be centrally
positioned between the four gimbal mounts shown to support the
underside of the reference surface 170 adjacent its middle area.
This may be particularly advantageous where very large sheets of
plate glass are employed.
[000104] Each of the four gimbal mounts 190 may comprise a
vertically oriented threaded member 193 threadibly engaged in a
co-operating threaded aperture 194 in the horizontal base plate
195 of the table frame 126. A concave recess 193r in the top
end 193t of the vertically oriented threaded member 193 receives
a ball bearing 196 in weight bearing relation. The ball bearing
196 receives a disk member 197 at a downwardly facing recess 198
in weight bearing relation. The
disk member 197 resides at
least partially within a circular recess 195r in the top surface
195t of the horizontal base plate 195. In
this manner, the
sheet of plate glass 172 that presents the reference surface 170
rests in vertically adjustable supported relation on the four
disk members 197. While
a relatively small degree of self-
levelling is built into the gimbal mounts 190 as illustrated and
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described, the vertically oriented threaded members 193 are each
independently rotatable to thereby selectively move the four
disk members 197 up and/or down, as necessary, to more fully
adjust the horizontal level of the reference surface 170 until
an operatively acceptable degree of horizontal level of the
reference surface 170 is achieved.
[000105] In an in-use sampling configuration, as can be best
seen in Figures 10 and 11, the container positioning member 150
is positioned over the base member 126 and the reference surface
170, with the congruent sample containers 130 each positioned
within a respective container-receiving socket 160. More
specifically, the congruent sample containers 130 each project
through both the upper container-receiving aperture 168 in the
upper plate 154 and the lower container-receiving aperture 169
in the lower plate 156. As such, the bases 132 of each of the
congruent sample containers 130 project through the bottom ends
164 of the container-receiving sockets 160 at the lower
container-receiving aperture 169, to thereby be supported in
weight bearing relation by the reference surface 170.
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[000106] It will also be noted that when the container
positioning member 150 is in the in-use sampling configuration,
the plurality of substantially vertically disposed container-
receiving sockets 160 are positioned, shaped and dimensioned
such that a gap 161 exists, as is best seen in Figure 10,
between the engagement portion 144 of the outer wall surface 138
of the congruent sample containers 130 and the container-
receiving rim portion 166 of the respective container-receiving
socket 160. In this manner, the congruent sample containers 130
have basically been temporarily released from contact with the
container positioning member 150 in order to be fully supported
by the reference surface 170.
[000107] Further, in the in-use sampling configuration, the
container positioning member 150 is supported in weight bearing
relation adjacent the reference surface 170, by means of its
feet 159 engaged in the co-operating foot-locating recesses 124
in the table frame 126 adjacent the reference surface 170.
[000108] As can be best seen in Figures 8 and 10, when the
system is removed from its in-use sampling configuration by, for
example, upward removal of the container positioning member 150
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from positioning over the reference surface 170, each of the
congruent sample containers 130 moves downwardly from its
position in the in-use sampling configuration, relative to the
container positioning member 150, to be supported by the
engagement portion 144 of the outer wall surface 138 contacting
the container-receiving rim portion 166 of the respective
container-receiving socket 160 in weight bearing relation
therewith. The
container positioning member 150 and the
congruent sample containers 130 retained by the container
positioning member 150 with the liquid samples 122 therein can
then readily be carried away from the base member 126 by a user.
[000109] Reference will now be made to the figures, which show
the system 120 according to the present invention in use. As
can be best seen in Figures 5 and 6, the congruent sample
containers 130 are being prepared for testing as a sample batch.
Figure 5 shows an empty sample container 130 ready to have a
volume of liquid sample 122 manually poured into it, and
sequentially Figure 6 shows a sample container 130 having about
seventeen (17) millilitres of liquid sample 122 having been
poured into it from a sample bottle 101, after the liquid sample
122 has been sufficiently mixed in, for example, the sample
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bottle 101 by the operator to evenly distribute any
contaminants. Figures 1 and 7 through 11 show a plurality of
congruent sample containers 130 retained by the container
positioning member 150 in place on the reference surface 170. A
liquid sample 122 having a volume of about seventeen (17)
millilitres has been poured into each of the congruent sample
containers 130. The exact volume is unimportant as long as the
volume is below the target volume of thirty (30) millilitres.
[000110] AS can be seen in Figures 8 and 10, when the container
positioning member 150 is removed from the in-use sampling
configuration, the partially full congruent sample containers
130 are supported by the engagement portion 144 of the outer
wall surface 138 contacting the container-receiving rim portion
166 of the respective container-receiving socket 160 in weight
bearing relation therewith. This configuration would be realized
when, for example, an operator carries the container positioning
member 150 and the congruent sample containers 130 to the base
member 126 and the associated optical particle counter 110, or
removes it therefrom after the optical particle counting testing
has been completed. Arrow
"A" in Figure 1 and arrow "B" in
Figure 8 indicate movement of the container positioning member
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150 and sample containers 130 contained thereby into the
operative in-use configuration by being lowered into position
atop the base member 126, as the feet 159 are indexingly
received by the co-operating foot-locating recesses 124 formed
in each of opposed side rails 126a of the base member 126. As
can be best seen in Figures 8 and 9, and as shown by arrows "C"
in Figure 9, the congruent sample containers 130 are received by
the previously levelled reference surface 170 as the container
positioning member 150 moves downwardly into contact with the
base member 126, into an in-use sampling configuration. In the
in-use sampling configuration, the container positioning member
150 is positioned over the reference surface 170 with the
congruent sample containers 130 each positioned within a
respective container-receiving socket 160 with the bases 132 of
the congruent sample containers 130 projecting through the
bottom ends 164 of the container-receiving sockets 160, to be
supported in weight-bearing relation by the reference surface
170.
[000111] In the in-use sampling configuration, (see Figures 9
and 11) the congruent sample containers 130 are all supported
with respect to a substantially level planar surface, namely the
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reference surface 170. Accordingly, testing errors induced by
having the sampling cups supported by an uneven or non-level
supporting surface, such as a prior art sample tray, is
virtually eliminated. As can be best seen in Figure 12, the
ultrasonic measuring device 117 can take an accurate and
meaningful measurement of the height of the top surface 122t of
the liquid sample 122 with reference to a substantially level
base reference point in each of the congruent sample containers
130, and thereby use this data to accurately calculate the
volume of the liquid sample 122 in each of the congruent sample
containers 130, and subsequently to calculate the amount of
diluent to be added to accurately achieve the desired final
volume of the mixture of the liquid sample 122 and the diluent.
More specifically, the sampling head 114 is positioned, by means
of the "X-Y" reference frame 127 operating under control of the
computer/CPU 112, over a selected sample container 130, whereat
the ultrasonic measuring device 117 is able to perform a height
measurement of the top surface 122t of the liquid sample 122 in
the selected sample container 130. In order to accomplish this
measurement, the ultrasonic transducer 117t of the ultrasonic
measuring device 117 transmits an ultrasonic signal to the top
surface 122t of the liquid sample 122 in the selected sample
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container 130, as indicated by arrow "D" of Figure 12. The
ultrasonic signal is reflected off the top surface 122t of the
liquid sample 122, and the reflected signal, as indicated by
arrow "E" of Figure 12, is received by the ultrasonic sensor
117s. Data related to the height of the top surface 122t of the
liquid sample 122, as compared to the height of the base 132 of
the sample containers 130 supported by the previously levelled
reference surface 170, is received by the computer/CPU 112.
Based upon the standard geometry of the congruent sample
containers 130, the computer/CPU 112 is able to accurately
calculate the volume of diluent 103 that needs to be added to
the selected sample container 130 in order to produce an overall
volume of mixture 107 of thirty (30) millilitres.
[000112] Next, with reference to Figure 18, the necessary
quantity of diluent 103 is drawn by the diluent syringe 108
moving in the direction indicated by arrow "F111, from the diluent
reservoir 109 through the diluent ingress port 108ip, with the
diluent syringe valve 108a open to the diluent reservoir 109
through the valve inlet 108vi, and open to the syringe 108
through the mouth 108m, as indicated by arrows "Fl" to "F2". As
can be seen in Figure 19, the diluent syringe valve 108a is then
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adjusted to be open to the inlet 115d of the outer diluent tube
115a, which is the diluent egress port 115e (see Figure 15),
through the mouth 108m and the valve outlet 108vo. The diluent
syringe 108 is then moved (as indicated by arrow "GI", in Figure
19), to inject the necessary quantity of diluent 103 into the
selected sample container 130, as indicated by arrows "G2". The
mixer 116 is then used to agitate the liquid sample 122 and the
diluent 103 until a substantially uniform mixture 107 is
achieved with the various particulates in suspension, as
indicated by arrow "H" in Figure 20.
[000113] Subsequently, as can be seen in Figure 21, an amount
of more than twenty-one (21) millilitres of the mixture 107 is
drawn, by movement of the mixture syringe 106 (in the direction
indicated by arrow "II") into the mixture syringe 106 from the
sample container 130 through the mixture ingress port 115i (as
indicated by arrow "12"), with the mixture syringe valve 106a
open to the sample container 130 through the valve inlet 108vi
and with the stop valve 102 open to the mixture syringe 106
through the mouth 106m. The mixture 107 is then de-gassed in a
suitable manner, the explanation of which is beyond the
necessary scope of the present disclosure, except to say that
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the stop valve 102 is closed to the ambient surroundings while
the mixture syringe 106 is moved again in the direction of "II".
Finally, the mixture syringe 106 is then moved in the direction
of arrow "J1" (as seen in Figure 22) to inject the de-gassed
mixture 107 into the optical sensing cell 111 of the automated
optical particle counter 110, preferably in three separate test
volumes of seven (7) millilitres each, as indicated by arrows
"3-2".
[000114] With this system, the congruent sample containers 130
can be accurately tested in a batch sequence by the automated
optical particle counter 110, due to an absence of interference
by "soft particles" with the optical sensing cell 111 of the
automated optical particle counter 110. It has been found that
the present invention produces a potential volume error of less
than 2%, which is well within the acceptable tolerances allowed
under the ASTM-D7647 test method, and which low level of error
is unattainable with prior art automated particle counting
systems not involving manual pipetting of the liquid samples 122
and diluents used in testing.
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[000115] This concludes the description of but one exemplary
embodiment of the invention. Many modifications and variations
are possible in light of the above teaching and will be apparent
to those skilled in the art. The scope of the claims should not
be limited by the preferred embodiments set forth in the
examples, but should be given the broadest interpretation
consistent with the description as a whole.
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