Petitioner: Haag-Streit AG
`Petitioner: Haag-Streit AG
`
`Ex. 10(cid:20)(cid:28)
`
`EX. 1019
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`

`

`[19]
`United States Patent
`6,069,687
`[11] Patent Number:
`Briggs May 30, 2000 [45] Date of Patent:
`
`
`
`
`
`USOO6069687A
`
`[54] CONTAMINANT DETECTOR
`
`[75]
`
`Inventor: Dennis Briggs, Westchester, Pa.
`
`[73] Assignee: Therakos, Inc., Exton, Pa.
`
`[21] Appl. No.: 08/976,386
`
`[22]
`
`Filed:
`
`N0v.21, 1997
`
`Related US. Application Data
`Provisional application No. 60/031,649, NOV. 22, 1996.
`
`Int. Cl.7 ..................................................... G01N 33/48
`356/39; 356/73
`
`Field of Search ................................. 356/39, 73, 410
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`.
`
`4/1982 Robertson et al.
`4,324,556
`10/1983 Steuer et al.
`.
`4,407,295
`4,775,794 10/1988 Behmann .
`4,810,090
`3/1989 Boucher et al.
`5,331,958
`7/1994 Oppenheimer .
`5,351,686
`10/1994 Steuer et al.
`............................ 128/633
`5,372,136
`12/1994 Steuer et al.
`.
`5,561,065
`10/1996 Schabron .
`FOREIGN PATENT DOCUMENTS
`
`.
`
`1/1992 European Pat. Off.
`0 467 804
`WO 94/29722 12/1994 WIPO .
`WO 95/04266
`2/1995 WIPO .
`
`.
`
`OTHER PUBLICATIONS
`
`“Silicon Carbide Blue LEDs”, Product Brochure, Cree
`Research, Sep. 1994.
`“VTB Process Diodes”, Product information, date unknown.
`
`Primary Examiner—Frank G. Font
`Assistant Examiner—Roy M. Punnoose
`
`[57]
`
`ABSTRACT
`
`Acontaminant detector including a light source for emitting
`light of a wavelength with peak emission corresponding to
`that of “blue” light or to that of light of even lower
`wavelength. Light is emitted through an arrangement con-
`taining a liquid sample having a given contaminant, and a
`sensing arrangement on the other side of the liquid sample
`detects the amount of light passing through the liquid
`sample. The measured light is converted into a value indica-
`tive of the relative presence of the given contaminant in the
`liquid sample. It is contemplated that other types of light can
`be used, particularly if the color of the light is matched, or
`even approximately matched, with that portion of the liquid
`sample that is not to be measured (i.e. the “background” or
`“non-contaminant” portion of the liquid.
`
`0 268 025
`
`5/1988 European Pat. Off.
`
`.
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`27 Claims, 8 Drawing Sheets
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`US. Patent
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`May 30, 2000
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`US. Patent
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`May 30, 2000
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`US. Patent
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`May 30, 2000
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`LED INPUT
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`ClHCU/THY
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`1
`CONTAMINANT DETECTOR
`
`This case claims benefit of Provisional application Ser.
`No. 60/031,649 filed Nov. 22, 1996.
`
`FIELD OF THE INVENTION
`
`The present invention generally relates to apparatus for
`quantitatively determining the presence of a given contami-
`nant or contaminants in a given liquid. The present invention
`also generally relates to apparatus for measuring hematocrit
`in human blood, or in blood products extracted or derived
`from human blood, and to processes for undertaking such
`measurements.
`
`BACKGROUND OF THE INVENTION
`
`Historically, it has often been important to determine the
`amount of a given contaminant or foreign substance present
`in a given product. For example, determinations of this
`nature can be vitally important
`if a product, during
`manufacture, needs to be screened in order that unduly
`contaminated portions thereof can be safely rejected and
`prevented from reaching the consumer public. Some
`examples of products in which such determinations might be
`important are, but are not limited to, the following: clear
`solvents (such as alcohol, paint thinner, turpentine, etc.);
`liquid pharmaceutical or medicinal products (e.g.
`liquid
`cold/fever medicines, hydrogen peroxide, liquids for use in
`vaporizers); various clear or “dye-free” products in the
`market place (including, among others, liquid soaps, deter-
`gents and waxes, shampoos, hair sprays, cosmetics,
`deodorants, topical medications, beverages, ingestible and
`parenteral alimentation solutions);
`fossil fuels, such as
`petroleum (either in crude or refined form); and other liquids
`which may either be essentially clear in nature or may have
`a given base color.
`in the context of medicine and
`As another example,
`physiology, there has often been a need to accurately deter-
`mine the levels of certain substances, which may be con-
`sidered “contaminants”, in a given portion of a patient’s
`bodily fluids. Such substances may be foreign to or naturally
`occurring in the human body. They may be innately unde-
`sirable or physiologically beneficial. By way of example, a
`brief discussion of red blood cells as a possible “contami-
`nant” in certain contexts is provided herebelow.
`Normally, human blood will contain a quantity of red
`blood cells and a quantity of white blood cells, in addition
`to other components. Historically, it has often been impor-
`tant to measure, with some accuracy, the presence of these
`constituent portions in a patient’s blood, in order to assist,
`for example, in the diagnosis of given diseases or disorders.
`One convenient parameter for assessing the relative pres-
`ence of different constituents in a sample of patient’s blood
`is the hematocrit parameter. Nominally,
`the hematocrit
`parameter will indicate, with some degree of accuracy, the
`degree to which the volume of the patient’s blood is
`accounted for by red blood cells. Generally, the hematocrit
`value can be expressed as a percentage or a decimal
`proportion, or by any other means for clearly expressing
`such a ratio or proportion. Thus, the hematocrit of a blood
`sample or blood product sample can be considered, for most
`purposes, as being roughly equivalent to the percentage (by
`volume) of the blood or blood product sample that
`is
`constituted by red blood cells.
`Conventionally, hematocrit measurements have often
`been determined for whole-blood samples,
`i.e. blood
`samples withdrawn directly from a patient which are not
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`subject to subsequent separation, treatment or other modi-
`fication. In addition, however, a tremendous value has often
`been placed on measuring hematocrit values with regard to
`a blood sample that has itself already undergone some type
`of modification or alteration, such as blood products, having
`been selectively extracted from a whole blood sample, that
`contain, for instance, a preponderance of white blood cells.
`In such instances, it is often extremely vital to ensure that
`hematocrit levels will not be excessively high, or, more
`particularly,
`that
`they will not exceed a predetermined
`threshold. It is in such instances that, for practical purposes,
`the red blood cells may be viewed as a “contaminant”.
`In the context of blood products containing a preponder-
`ance of white blood cells, the need for accuracy in hemat-
`ocrit measurements has been widely recognized.
`Particularly, it has been widely recognized that the accept-
`able margin of error in taking hematocrit measurements of
`blood products containing a preponderance of white blood
`cells is tremendously smaller than in the case of measuring
`whole-blood samples. Therefore, even though a margin of
`error built into a given measuring apparatus or process might
`arguably have a negligible effect in the context of whole
`blood samples (e.g., blood samples in which the hematocrit
`value is on the order of magnitude of 50% or higher), it
`would, in proportion to the actual hematocrit values present,
`be much more significant in the context of a blood sample
`containing a preponderance of white blood cells (e.g., a
`blood sample having a hematocrit value on the order of
`magnitude of only a few percent or less).
`The need for a high degree of accuracy at low levels of
`hematocrit might be especially important in order to prop-
`erly diagnose or verify a particular disorder or disease the
`patient might have in order to provide proper treatment for
`the patient. For example, if a blood sample is extracted from
`a patient, and then is subsequently separated in a centrifuge
`or other cell separating device, it might be extremely impor-
`tant to ensure that the hematocrit level is sufficiently low in
`order for the blood sample to be able to undergo subsequent
`treatment, such as irradiation in an irradiation apparatus. In
`this vein, it is a distinct possibility that an unduly high level
`of hematocrit in a patient’s blood sample (i.e., a blood
`sample containing a preponderance of white blood cells),
`even on the order of magnitude of a few tenths of a
`percentage point or less, could subsequently result in rela-
`tively ineffective treatment (thus either delaying or even
`jeopardizing the possibility of the patient’s recovery), or
`could simply represent an undesirable waste of time and
`resources (in that a complete restart of the procedures of
`withdrawing, centrifuging and treatment might be
`necessary).
`Conventionally, one method of measuring hematocrit
`involves the centrifuging of a sample with a standard
`centrifuge and a capillary tube. A physical measurement is
`made of packed red cells in the tube, and a hematocrit
`calculation is derived therefrom. However, disadvantages
`are found in that the blood must first be collected and then
`
`centrifuged, and in that results are generally not immediately
`available. Further, results tend not to be highly accurate at
`lower hematocrit levels, such as hematocrit levels of about
`30% or less.
`
`Another conventional method contemplates a technique
`in which two LED (light-emitting diode) emitters of differ-
`ing wavelength (typically red [i.e., generally about 600 nm]
`and green [i.e., generally about 500 nm]) are modulated
`through a sampling cuvette. A photodiode and electrical
`circuit amplify the light that has originated from the emitter
`and passed through the cuvette. Once the LED has been
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`6,069,687
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`3
`switched on and permitted to stabilize, a measurement is
`made of the difference in the signal amplitude of the
`modulated light. A computer calculates the hematocrit mea-
`surement based differences in the light reaching the detector.
`Results obtained in connection with such systems tend not to
`be accurate with respect to blood products samples having
`significantly low hematocrit levels (such as about 6% or
`less), and response time tends to be slow in view of the use
`of modulated light and in view of the response time of the
`photodiode circuit. These systems tend to be highly complex
`in view of the light modulation technique and the need to
`compute the difference between two detector readings.
`US. Pat. No. 5,351,686 to Steuer et al. discloses an
`arrangement in which a disposable cuvette, through which
`pulsatile flowing blood is to pass, has a conduit with two
`opposed walls having a predetermined separation therebe-
`tween that varies with each pulse of the flowing blood. In
`this procedure, it is possible to produce a value indicative of
`the change in a patient’s hematocrit from one point in time
`to another, as well as values indicating absolute hematocrit.
`However, since this patent to Steuer et al. appears only to
`contemplate the detection of hematocrit in whole blood, it
`would appear that the apparatus disclosed therein may not be
`as accurate as desired at relatively low levels of hematocrit
`(as discussed more generally heretofore).
`US. Pat. No. 5,372,136 to Steuer et al. discloses a system
`and method for hematocrit monitoring in which,
`for
`example, a finger may be inserted into a tube-like structure
`or a clip may be placed on an earlobe. In either case, a
`photodiode arrangement assists in the determination of a
`hematocrit value on the basis of the extinction of various
`
`wavelengths of light that have traveled through the human
`body part in question. This procedure involves what may be
`called a “non-invasive” detection of hematocrit. However, it
`only appears to be capable of determining a value indicative
`of a change in a patient’s hematocrit from one point in time
`to another, and not absolute values of hematocrit. Further,
`the apparatus disclosed in this patent to Steuer et al. would
`also appear to encompass similar disadvantages as described
`immediately above and more generally heretofore (that is, it
`may not be as accurate as desired at
`low levels of
`hematocrit). Additionally, there would also appear to be a
`potential distorting factor arising from the passage of light
`through additional,
`intervening media, e.g.,
`the patient’s
`skin, bone, muscle and other bodily components.
`It
`is believed that
`the known devices and processes
`discussed and alluded to hereinabove, for the most part, are
`complex and expensive, and present results that are not as
`accurate as may be desired.
`In view of the foregoing, a need has arisen for the
`provision of a detector or detectors that can, in the presence
`of a given liquid containing an undesirable substance or
`contaminant therewithin, accurately ascertain the degree of
`the contaminant’s presence.
`SUMMARY OF THE INVENTION
`
`In accordance with at least one embodiment of the present
`invention, an apparatus and method are contemplated in
`which preferably a single light source, for emitting light of
`a wavelength with peak emission generally corresponding to
`that of “blue” light in the visible spectrum or to that of light
`of even lower wavelength, emits light through an arrange-
`ment containing a liquid sample, for which it is desired to
`measure or detect a given contaminant. Further, a sensing
`arrangement located on the other side of the liquid sample
`preferably detects the amount of light passing through the
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`liquid sample. Appropriate circuitry will preferably convert
`the measured light into a value indicative of the relative
`presence of the given contaminant in the liquid sample. With
`such an arrangement, it is also conceivable to detect instan-
`taneous changes in the level of the contaminant in question.
`In this posture, it has been found that significantly accu-
`rate measurements of the presence of a given contaminant in
`a given liquid can be obtained if, as a general rule, a
`principle of “color affinity” is followed in exposing tne
`liquid to light during a detection procedure. For example,
`since “blue” wavelengths of light (or light of lesser
`wavelengths) tend to mimic the “color”, or lack of color,
`present in white blood cells more closely than does light of
`higher wavelengths (such as red and/or green wavelengths),
`it appears that, especially in the context of a blood sample
`containing a preponderance of white blood cells, the pres-
`ence of red blood cells is much more likely be distinguished
`by a detector using blue light (or light of lesser wavelengths)
`than if red or green light were being passed through the
`blood sample in question. It will be appreciated that, con-
`sistent with the present invention, similar principles can be
`applied to measuring contaminants in liquids other than
`bodily fluids including, without limitation, consumer and
`industrial products.
`Thus, a great deal of accuracy can be obtained by essen-
`tially matching, or even approximately matching, the color
`of the light being emitted to that portion of the liquid sample
`that
`is not being directly measured (i.e.,
`the non-
`contaminant, “background” or “fundamental” portion of the
`liquid) but whose purity may be derived through measure-
`ment of the contaminant content therein. In this manner, it
`would appear to be much easier to ascertain the presence of
`contaminants that differ significantly in color from the light
`being directed through the liquid sample in question.
`In accordance with at least one preferred embodiment of
`the present invention, a particular advantage may be found,
`in the context of measuring hematocrit in a blood product
`sample containing a preponderance of white blood cells, and
`especially in instances in which the blood produce sample is
`destined for irradiation in an irradiation apparatus, in that
`light having a wavelength substantially corresponding to
`that of “blue” light can be considered as closely mimicking
`UV—A light (i.e., light having a wavelength of about 352
`nm), which UV—A light itself is often used in such irradiation
`procedures. Thus, by closely mimicking the physical char-
`acteristics of light that is later to be used on the same blood
`product sample during an irradiation procedure, the likeli-
`hood that any portion of the blood product sample being
`measured in a hematocrit detector will be unduly effected or
`altered by the light from the LED is greatly reduced.
`In summary, one aspect of the present invention broadly
`contemplates a device for measuring hematocrit, the device
`including:
`a light source for emitting light along a predetermined
`path;
`an arrangement for disposing a portion of a human blood
`sample in the path of light emitted by the light source,
`wherein the light source emits light having a peak
`emission wavelength no greater than that of blue light;
`an arrangement for sensing light that has originated from
`the light source and that has passed through a portion
`of a human blood sample disposed, by the disposing
`arrangement, in the path of light emitted by the light
`source; and
`an arrangement for converting the light sensed by the
`sensing arrangement to a hematocrit value.
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`5
`In another aspect, the present invention broadly contem-
`plates apparatus for measuring a contaminant present in a
`liquid, the apparatus comprising:
`a light source for emitting light along a predetermined
`path;
`an arrangement for temporarily disposing a portion of a
`liquid sample,
`the sample containing a contaminant
`portion and a non-contaminant portion, in the path of
`light emitted by the light source,
`the contaminant
`portion of the liquid being identifiable by emission
`thereof of light predominantly comprised of a first
`wavelength and the non-contaminant portion of the
`liquid being identifiable by emission thereof of light
`predominantly comprised of a second wavelength dif-
`ferent from the first wavelength;
`an arrangement for sensing light that has originated from
`the light source and that has passed through a portion
`of a liquid sample disposed, by the disposing
`arrangement, in the path of light emitted by the light
`source; and
`an arrangement for converting the light sensed by the
`sensing arrangement to a value indicative of the pres-
`ence of the contaminant portion in the liquid sample;
`wherein the light source comprises an arrangement for
`emitting light having a peak emission wavelength that
`is substantially no greater than the second wavelength.
`In yet another aspect, the present invention broadly con-
`templates a method of measuring a contaminant present in a
`liquid, the method including the steps of:
`providing a light source for emitting light along a prede-
`termined path;
`obtaining a liquid sample containing a contaminant por-
`tion and a non-contaminant portion, the contaminant
`portion of the liquid being identifiable thereof by
`emission of light predominantly comprised of a first
`wavelength and the non-contaminant portion of the
`liquid being identifiable by emission thereof of light
`predominantly comprised of a second wavelength dif-
`ferent from the first wavelength, the non-contaminant
`portion having a given color;
`disposing a portion of the liquid sample in the path of light
`emitted by the light source;
`emitting light through the liquid sample portion;
`sensing light that has originated from the light source and
`has passed through the liquid sample portion; and
`converting the light sensed to a value indicative of the
`relative presence of one of:
`the contaminant portion in the liquid sample; and
`the non-contaminant portion in the liquid sample;
`wherein the light source emits light having a peak emis-
`sion wavelength that is substantially no greater than the
`second wavelength.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`invention, as contemplated in accordance
`The present
`with at least one preferred embodiment thereof, will be more
`readily understood with reference to the accompanying
`drawings, wherein:
`FIG. 1 illustrates a contaminant detector in exploded
`view;
`FIG. 2 provides a detailed illustration of a cuvette;
`FIG. 3 is a front elevational view of the contaminant
`detector illustrated in FIG. 1, with a cover and cuvette in
`place (in preparation for a detection procedure);
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`FIG. 4 is substantially the same view as FIG. 3, but with
`the cuvette and cover being removed;
`FIG. 5 is a plan view of the contaminant detector shown
`in FIGS. 1, 3 and 4;
`FIG. 6 is a cutaway view taken substantially along the line
`VI—VI shown in FIG. 5;
`FIG. 7 is a cutaway view taken substantially along the line
`VII—VII shown in FIG. 5;
`FIG. 8 is a schematic illustration of a detection arrange-
`ment;
`FIG. 9 is a perspective view of an alternative cuvette
`according to the present invention;
`FIG. 10 is a perspective view, in partial section, of an
`alternative light assembly according to the invention for
`receiving the cuvette of FIG. 9; and
`FIG. 11 is a perspective view of the cuvette of FIG. 9
`received within a recess on the light assembly of FIG. 10.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`FIG. 1 illustrates a contaminant detector according to a
`preferred embodiment of the present invention. Particularly,
`FIG. 1 shows a contaminant detector 10, in exploded view,
`as having cover 12 and a main body 14. Also shown is a
`cuvette 27 that is selectively insertable into the main body 14
`in a manner that will be described in greater detail herein-
`after.
`
`In accordance with at least one preferred embodiment of
`the present invention, a mounting block 23 may be mounted
`on a suitable mounting plate 21. In turn, mounting block 23
`may preferably form a base for main body 14. As shown in
`FIG. 1, main body 14 could preferably be constituted by a
`larger cylindrical portion 25 and a smaller cylindrical por-
`tion 29 (i.e., “larger” and “smaller” in terms of their relative
`diameters). Further, on a surface 21a of mounting plate 21,
`it
`is conceivable to mount,
`in any appropriate manner,
`circuitry for the purpose of processing measurements taken
`by the detector 10. Alternatively, such circuitry could be
`provided on that surface of mounting plate 21 disposed
`opposite from surface 21a.
`Preferably, smaller cylindrical portion 29 will have a slot
`18 disposed therein that is suitable for accommodating the
`aforementioned cuvette 27. Also preferably provided in
`cylindrical portion 29 is a light-emitting diode (LED)
`arrangement or other suitable light source 20 for emitting
`light during measurement procedures.
`To facilitate the propagation of light through cuvette 27
`(when inserted in main body 14),
`the main body further
`preferably comprises a first passage 22 leading from LED 20
`to slot 18 and a second passage 24 leading from the slot 18
`to a suitable sensing arrangement 26 (see FIG. 5).
`Preferably, slot 18 will accommodate cuvette 27 in a
`manner that permits the light emitted by LED 20 to pass
`through cuvette 27 and onward to sensing arrangement 26
`(again, see FIG. 5). Preferably, for the duration of a detection
`procedure, cover 12 will be placed over main body 14 in
`such a manner as to significantly minimize, if not virtually
`completely eliminate, the ingress of ambient light (i.e., light
`from outside of the apparatus) towards cuvette 27.
`FIG. 2 more closely illustrates a cuvette 27 that may be
`utilized in accordance with a preferred embodiment of the
`present invention. Preferably, cuvette 27 will include an
`infeed line 28, an outfeed line 32 and a main body portion
`34.
`
`Main body portion 34 will preferably be so configured as
`to include therewithin a portion defining a “flattening”
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`6,069,687
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`7
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`(which could be alternatively termed an
`chamber
`“exposure”, “detection” or “testing” chamber) 36 of signifi-
`cantly small
`thickness to effectuate the provision of a
`significantly thin layer of a blood product sample in the path
`of light emitted from the light source 20. In one embodiment
`of the present invention, the thickness of chamber 36 could
`be about 0.030 inch (resulting in a blood film layer of similar
`thickness), but slightly larger or smaller thicknesses could
`also be used.
`
`Preferably, main body portion 34 will also be so config-
`ured as to readily accommodate infeed and outfeed lines 28
`and 32 so that infeed and outfeed lines 28 and 32 may
`respectively direct blood portions into and out of chamber
`36 via suitable interior conduits 28a and 32a.
`Interior
`
`conduits 28a and 32a may be generally tubular in nature and
`may effect a transition into chamber 36 via suitably config-
`ured transition zones 31 and 33. Preferably, chamber 36 will
`be so configured as to present a thin, and substantially
`laminar,
`layer of liquid to light emitted from LED
`arrangement, or other suitable light source 20 (see FIG. 1).
`In accordance with at least one preferred embodiment of the
`present invention, at least chamber 36 is made of an essen-
`tially transparent material (e.g., a clear plastic). It will be
`understood that the balance of the main body portion 34, as
`well as the infeed and outfeed lines 32, 34 may be made of
`similar material (although materials of greater opacity may
`be more preferable for these components in order to further
`inhibit the ingress of ambient light into chamber 36).
`FIG. 3 illustrates the contaminant detector with the
`
`cuvette 27 inserted into slot 18 (see FIG. 1) and with cover
`12 in place, in preparation for a detection procedure.
`FIG. 4 is a front elevational view of a contaminant
`
`detector according to the present invention, with the afore-
`mentioned cover 12 being removed. The aforementioned
`LED arrangement 20 is preferably positioned in a suitably
`dimensioned slot 38.
`
`FIG. 5 is a plan view of the contaminant detector shown
`in FIG. 3. As illustrated, slot 18 preferably spans at least the
`diameter of the smaller cylindrical portion 29 of main body
`14.
`
`FIG. 6 is a cut-away view taken substantially along the
`line VI—VI shown in FIG. 5. As shown, slot 18 will
`preferably be so configured as to fully accommodate cuvette
`27, and thus preferably includes a downward recessed
`portion 42. Preferably, downward recessed portion 42 will
`contain a window 43 that, upon placement of cuvette 27 in
`slot 38, will be aligned with the aforementioned flattening
`chamber 36 of cuvette 27 so as to direct light into second
`passage 24 (see FIG. 5).
`FIG. 7 is a cut-away view substantially taken along the
`line VII—VII shown in FIG. 5. As shown, this portion of
`main body 14 will preferably have a hole 44 disposed
`therewithin configured for directing LED or other light from
`first passage 22 (see FIG. 5) towards flattening chamber 36
`of cuvette 27 and thence to the aforementioned window 43.
`
`FIGS. 6 and 7 illustrate that, in accordance with at least
`one preferred embodiment
`to the present
`invention,
`the
`aforementioned cuvette-accommodating slot 18 (see FIG. 5)
`can preferably be constituted by: downward recessed portion
`42, substantially horizontal ledge portions 45 and substan-
`tially vertical wall portions 47. Downward recessed portion
`42 itself may preferably be constituted by a first vertical wall
`portion 42a (as shown in FIG. 6) and a second vertical wall
`portion 42b (as shown in FIG. 7).
`Preferably, portions 42a, 42b, 47 and 45 will be so
`dimensioned and configured as to adequately accommodate
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`cuvette 27 when the same is inserted into slot 18 and
`
`supported within downward recessed portion 42. In this
`regard, when cuvette 27 (see FIG. 2) is inserted into down-
`ward recessed portion 42, a significant portion of main body
`34 of cuvette 27 will preferably be cradled in downward
`recessed portion 42. So configured, the infeed and outfeed
`lines 28 and 32 will preferably respectively rest on corre-
`sponding horizontal ledge portions 45, whereas opposite
`longitudinal ends of cuvette 27 will substantially abut
`against corresponding vertical wall portions 47. Preferably,
`with respect to the view shown in FIG. 6, vertical wall
`portion 42a will preferably be axially more recessed than
`vertical wall portions 47, in order to readily accommodate
`the thickness of main body 34 beyond the infeed and outfeed
`lines 28 and 32. With infeed line 28 and outfeed line 32 of
`
`cuvette 27 resting on horizontal ledge portions 45, the same
`will also preferably be accommodated by suitably dimen-
`sioned recesses 48 in cover 12 (one of which is shown in
`FIG. 1).
`Preferably, window 43 leads to passage 24 and terminates
`at suitable sensing device, or sensor, 26 (see FIG. 5). Such
`a sensor 26 is schematically indicated in FIG. 8, with the
`LED input being indicated schematically at 50. Preferably,
`sensor 26 will be connected to suitable circuitry and/or
`programming 52 for the purpose of determining the actual
`contaminant level in the liquid sample in question.
`FIGS. 9 to 11 illustrate a further embodiment of the
`invention. FIG. 9 shows an alternative cuvette 100 molded
`
`of an opaque plastic or other suitable material. The cuvette
`100 comprises a flat elongated body 102 having an integral
`light shield flange 104 molded over ends 106 and an upper
`edge 108 of the body 102. Ports 110 and 112 connect to the
`tubing (not shown) as in the prior embodiment. Passageways
`114 and 116 lead from ports 110 and 112 respectively into a
`discoidal viewing chamber 118. The chamber 118 is defined
`by an annular wall 120 normal to and penetrating the body
`102. Apair of transparent windows 122 are sonically welded
`within the wall 120, abutting an annular ledge 124 within the
`chamber 118, to enclose the chamber 118. A longitudinal
`vane 126, coplanar with the body 102, extends through an
`upper portion of the chamber 118 between the windows 122
`to promote laminar flow of sufficient velocity to carry any
`entrained air bubbles out of the chamber 118.
`
`FIG. 10 shows an optical assembly 128 for receiving the
`cuvette 100 (not shown in FIG. 10). The assembly 128
`comprises a body 130 formed of an opaque material having
`a recess 132 shaped to receive the cuvette 100, with an LED
`134 on one side thereof and a photodiode 136 on an opposite
`side thereof. Awindow 138 separates the LED 134 from the
`recess 132. FIG. 11 shows the cuvette 100 received within
`
`the recess 132. The light shielding flange 104 and the optical
`assembly body 130 shield the chamber 118 from ambient
`light sources. The LED 134 can direct its light through its
`window 138, through the chamber windows 118, and the
`chamber 118 to be received by the photodiode 136. The
`hematocrit level of fluids flowing through the chamber 118
`can thus be measured quickly and easily.
`It is to be understood that, in accordance with at least one
`preferred embodiment of the present invention, the contami-
`nant detectors described and illustrated with respect
`to
`FIGS. 1 to 11 provide only illustrative examples and are in
`no way meant to limit the scope of the present invention.
`It will be appreciated that the structural and functional
`aspects of the present invention may be applicable to a wide
`variety of contexts, involving a wide variety of liquids and
`associated contaminants. Thus, although specific reference
`
`

`

`6,069,687
`
`9
`has been made to the context of detecting the presence of red
`blood cells in a human blood sample containing a prepon-
`derance of white blood cells, it is to be understood that other
`liquids and other contaminants can conceivably be adopted
`within the scope and spirit of the present invention, espe-
`cially by employing the concept of “color affinity” described
`and alluded to throughout the instant application. Examples
`of such liquids include, but are not limited to: clear solvents
`(such as alcohol, paint
`thinner,
`turpentine, etc.);
`liquid
`pharmaceutical or medicinal products (e.g. liquid cold/fever
`medicines, hydrogen peroxide, liquids for use in vaporizers);
`various clear or “dye-free” consumer products in the market
`place (including, among others, liquid soaps, detergents and
`waxes, shampoos, hair sprays, cosmetics, deodorants, topi-
`cal medications, beverages, parenteral alimentation
`solutions); fossil fuels, such as petroleum (either in crude or
`refined form); and other liquids which may either be essen-
`tially clear in nature or may have a given base color.
`It will be appreciated that, in accordance with at least one
`preferred embodiment of the present invention, and espe-
`cially in the context of determining hematocrit values in
`human blood or blood product samples (particularly blood
`samples containing a preponderance of white blood cells