Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THE INVENTION
` 1. Pield of the Invention
; This invention relates to an automated llquid sample -
analyzer having a fluid system for proportioning two liquids in
highly reproducible volumes, ~ith substantial independence with
respect to the flow rates of such liquids.
2. Prior Art
; In automated apparatus for quantitatively analyzing se-
quentially a series of samples of blood or other liquids for
one or more constituents of interest, it has been common to
proportion various liquids utilized in the analytical process
. by employing a proportioning unit comprising a peristaltic pump ~-
and a manifold including compressible pump tubes. This general
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type of apparatus is illustrated, for example, in Skeggs et al
U.S. Patent 3,241,432 issued March 22, 1966. Such liquid
proportioning has been highly dependent on flow rates in the
various manifold tubes. The flow rates and the liquid proportion-
ing have been subject to variations effected by such factors
as changes in the effective diameters of the tubes, temperature
~ 20 and fluid viscosity for example. Changes in proportioning of
~` liquids such as sample, diluent or reagent adversely affects the
analytical results of such an automated analyzer.
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It is also known that a shear valve has been
. utilized in an automated analyzer to provide a fixed-volume
chamber for only a single liquid such as the sample to
obtaîn a reproducible volume of such samp].e, the sample
.- volume being displaced from the chamber toward an analysis
station by a pilot fluid. One such apparatus is illustrated
in Isreeli et al U.S. Patent 3,583,232 issued June ~, 1971.
The present invention relates to a method of
: proportioning liquids in a fluid sample analyzer, comprising
the steps of filling a first chamber of fixed-volume with
. a first liquid, filling a second larger chamber offixed-
.~ volume with a second liquid to be combined with the first
liquid; displacing the volume of the first liquid in the
. first chamber into the filled second chamber, using a
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quantity of the second liquid as a pilot liquid; and
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exh.austing concurrently a volume of the second liquid by
. overflow from the second chamber equal to the volume of the ~::
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. first liquid and any pilot fluid introduced into the second
chamber. ;~.
In its apparatus aspect the invention relates to
a liquid proportioning system in a fluid sample analyzer
comprising; means for flowing a first liquid along a first -~
conduit for filling means defining a first chamber of fixed
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volume; means for flowing a second liquid along a second
conduit for filling means defining a second larger chamber
of fixed volume; means for flowing a different quantity of
the second liquid as a pilot fluid along a third conduit
: to the first chamber; and first means for selectively .
coupling the first chamber to the second chamber, the last- ~.
named means coupling the chambers during the flow of the
;; pilot fluid such that the volume of the flrst liquid in the ~ .
first chamber i8 displaced into the filled second chamber,
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the means defining the second chamber comprising means
for overflowing a volume of the second liquid from the
second chamber equal to the volume of the first liquid and
any pilot fluid introduced into the second chamber.
Specifically, there is provided a liquid sample
analyzer having a first fixed-volume chamber-into which
a first liquid is flowed filling it for subsequent dis-
placement of the liquid volume therefrom by a second
liquid into a substantially larger second fixed-volume
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; 10 chamber through a first port thereof, the second liquid
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; acting as a pilot fluid. Prior to such liquid volume
~ displacement from the first chamber, the second chamber,
- having an overflow outlet at a location remote with respect
to the first port, is washed out and filled to an overflow
level by a flow of the second liquid entering the second
c~amber through a second port. On such dis-
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placement of the volume of the first liquid into the second
chamber, the last-mentioned volume and a relatively small volume
of the second liquid entering the second chamber displace from
the second chamber through the aforementioned outlet an equi-
valent volume of the second liquid, so that a reproducible
volume of the first liquid remains in the second chamber with a
reproducible volume of the second liquid. One of the liquids
may be a sample and the other may be a diluent. The contents ;
of the second chamber may be analyzed therein and/or withdrawn
for analysis elsewhere.
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BRIEF DESCRIPTION OF THE DRAWINGS
` In the Drawings:
Fig. 1 illustrates diagramatically in a fragmentary view
a liquid sample analyzer having a liquid proportioning system
embodying the invention;
Fig. 2 is a diagrammatic fragmentary view illustrating
a modified form of the invention, showing a liquid proportion- -
ing probe immersed in a source of one liquid;
Fig. 3 is a fragmentary view illustrating the probe of
Fig. 2 transferred relatively to the first liquid source and
immersed in a source of a second liquid; and
Fig. 4 is a fragmentary view illustrating the probe of
Fig. 2 transferred relatively to the source of the second liquid
and in a position to dispense the first and second liquids to-
gether into a receptacle in proportioned condition.
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DETAILED DESCRIPTION OF T~E INVENTION
In the form of Fig. 1, there is provided a series of
~ receptacles, each for containing sample liquid such as whole
blood, for example, for quantitative analysis of plural con- ;
stituents therein such as hemoglobin and white cell count by
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way of example, one such receptacle being indicated a~ 10. An
open-ended tubular probe 12 is shown immersed in the liquid of
receptacle 10 and has an outlet end coupled to the inlet end of
compressible tube 14. Connected to the tube 14 intermediate
the ends thereof is the inlet end of a compressible tube 16
which extends through a peristaltic pump 18. In proximity to the
junction of the tube 16 with the tube 14, there is a pinch valve
20 which is electrically operated and which cooperates with the
compressible tube 16. A programmer 22 has an output to the in-
put of a lead 24 which has an output to the valve 20. A com-
pressible pump tube 26 has an inlet end immersed in the liquid
of a container 28 which liquid is a diluent and may be Drabkin's
reagent with a lysing agent. The tube 26 extends through the
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pump 18 and has an outlet end connected to the tube 14 inter-
; mediate the end thereof connected to the probe 12 and the junction
of the tube 14 with the tube 16. Intermediate the ~unction of
the tube 14 with the tube 26 and the inlet end of tube 14, there
is an electrically operated pinch valve 30 cooperating with the
tube 14. The programmer 22 has an output which is connected
to the input of lead 32 which has an output to the valve 30.
Further, near the junction of the tube 26 with the tube 14, there
is an electrically operated pinch valve 34 cooperating with the
pump tube 26. The programmer 22 has an output to the input of
a lead 36 having an output to the valve 34.
A body or flowcell 38 is provided defining a vertically
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arranged chamber 40 having a restricted overflow outlet 42 in
: the top thereof and extending upwardly through the bottom of an
integral bowl shaped catch basin 44, the basin being open to at-
mosphere at the top and having a lower lateral drain outlet 46
waste. The flowcell 38 has a lower lateral opening or first
port to which the outlet of the compressible tube 14 is connected.
A pinch valve 45 cooperates with the tube 14 near the outlet
end thereof. The programmer 22 has an output to the input of a
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lead 47 which has an output to the valve 45. In the illustrated
form, the body or flowcell 38 is structured of a transparent
substance such as glass so that the contents of the body may
be photometrically analyzed in the chamber 40 in a manner which
will be described hereinafter.
The flowcell 38 has a bottom opening or second port to
which is connected one end of a tube 48. In this form shown, ;~
the tube 48 is structured as a transparent glass flowcell for
analysis of liquid in the tube 48 as will be described herein-
after. The other end of the tube 48 i5 connected to one arm of
a T fitting 50.
A compressible tube 52 extends through the pump 18 and
has an inlet end immersed in the diluent in the container 28.
The outlet end of the tube 52 is coupled to a lower lateral in-
let of a container 54 which has a lower lateral outlet coupled
to the inlet end of a compressible tube 56. The outlet end of
the tube 56 is connected to another arm of the T fitting S0. An
electrically operated pinch valve 58 cooperates with the tube 56 ;
in proximity to the T fitting 50. The programmer 22 has an out-
put connected to the input of a lead 60 which has an output
connected to the valve 58. The container 54 is closed ex-cept for
the aforementioned connections thereof to the tubes 52 and 56,
and forms a chamber 55 which in practice is preferably at least ;~
twice the size of the chamber 40 defined by the flowcell 38. Air
is constantly trapped in the chamber 55 above the diluent level
therein and the aforementioned tube connections thereof. This ,~
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trapped air serves to pressurize the chamber 55 when the valve
58 occludes the tube 56 and the chamber 55 is substantially
filled with diluent by the action of the pump 18 on the pump ~ -
tube 52. In the operation of the apparatus shown in Fig. 1, the
pump 18 is operated continuously.
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A compressible tube 62 has an inlet end connected to the
remaining arm of the T fitting 50 and has an outlet end con-
nected to a lateral inlet of a vessel 64 providing a chamber 66
which has a bottom outlet connected to the inlet end of a com-
pressible tube 68 extending through the pump 18. Except for the
aforementioned inlet and outlet connections, the chamber 66 is
closed. In practice the chamber 66 is preferably at least tuice
the size of the chamber 40. A pinch valve 70 cooperates with
the tube 62 in proximity to the T fitting 5C. The programmer 22
has an output to the input of a lead 72 which has an output to
the valve 70. When the valve 70 occludes the tube 62, the
action of the pump 18 on the pump tube 68 effects a vacuum in
the chamber 66.
An electrical mixer motor 73 is suitably supported a
distance above the catch basin 44. The motor shaft extends down-
wardly into the chamber 40 through the overflow outlet S2 thereof, -
the shaft having a paddle 74 fast thereon. The programmer 22
has an output to the input of a lead 76 which has an output to
the motor 73.
In this form, a particle counter, indicated generally at
78, is associated with a portion of the flowcell 48 and may take
the form conveniently of the particle counter described in detail
in Isreeli U.S. Patent 3,511,573 issued May 12, 1970. The
particle counter 78 includes a light source 80 from which a
light path is directed through the flowcell onto a photomulti-
plier 82. The particle counter 78 is provided with non-
illustrated data processing and analytical-result display as de-
scribed in the last-mentioned patent. Operation of the particle
counter 78 may b-e initiated in a conventional non-illustrated
manner on opening of the valve 70. In this form, spaced up-
wardly from the particle counter 78 is a light source 84 from
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- which a light path is directed through the flowcell 48 onto a
photocell 86. A signal from the photocell 86 may shutdown the
operation of the particle counter in a conventional non-
illustrated way and in a sequence to be described hereinafter.
As previously lndicated, sample analysis may take place
in the chamber 40 of the flowcell 38, and this analysis may be
a photometric analysis utilizing a colorimeter including a
photocell operationally driving a pen recorder in the manner
described in Skeggs U.S. Patent 2,797,149 issued June 25, 1957.
For present purposes, it is sufficient that for such analysis
there is provided a light source 88 from which a light path is
- directed through the flowcell 38 and the chamber 40 thereof
- onto a photocell 90.
In this form illustrated by way of example only, es-
pecially with reference to the particular sample and the tests
performed thereon but not limited thereto the sample is whole
blood and the analyses are for quantitative determinations of
hemoglobin and white cell count.
The operation of the apparatus of Fig. 1 will now be
; 20 described. It has been indicated previously that the sample
receptacle 10 i8 one of a series of such receptacles, and for
purposes of explaining the operation, the assumption is made
that a sample of whole blood from another such receptacle, the
first sample, has been previously aspirated into the apparatus,
- analyzed therein and discharged therefrom. When the probe 12
is immersed as shown in the sample of whole blood in the re-
ceptacle 10, the second sample, and valves 30 and 20 are the
only valves in open condition, the second sample is aspirated
through the probe 12 into the compressible tube 14 and outletted
therefrom into the pump tube 16 through the action of pump 18.
Concurrently, pump tube 52 aspirates diluent, in the form of
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the aforementioned Drabkin's reagent with a lysing agent, from
- the container 28 into chamber 55 causing the diluent therein to
be pressurized. The ~.ixer motor 22 is deenergized. As previously
described, all the valves are controlled by the programmer 22.
Valve 58 then opens allowing diluent to pass the valve in com-
pressible tube 56, so that diluent from the pressure chamber 55
flows through the corresponding arms of fitting 50 and through
the connected flowcells 48 and 38 and out overflow outlet 42.
This washes out traces of the first sample from the flowcell 48
and the fixed-volume chamber 40 of the flowcell 38. The diluent
exiting from the overflow outlet 42 spills into the catch basin 44
and leaves the latter through drainage outlet 46 thereof. Any
gas present escapes through the outlet 42 to the atmosphere. A
flow of the diluent from the pressure chamber 55 of 1.5 times -
the combined volumes of the flowcell 38 and the flowcell 48 is
presently considered the minimum volume necessary to washout
and fill the flowcell 38 and the flowcell 48. The valve 58
closes leaving these cells full of diluent. Concurrently with
all the foregoing, the pump tube 68 through the action of the
pump 18 effects a vacuum in the chamber 66 of the vessel 64.
- Valves 30 and 20 close and valves 34 and 45 open. This
permits diluent from the container 28 to flow in pump tube 26
past the valve 34. This flow enters tube 14 and displaces the
portion of the sample in the tube 14 between the junction of
tubes 14 and 26 and the junction of tubes 14 and 16. This
sample portion is displaced past the valve 45 into the chamber 40
of the flowcell 38 through the tube 14. It will be understood
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that the portion 14a of the tube 14 between the last-mentioned
junctions thereof constitutes a fixed-volume liquid chamber. In
such displacement of the fixed sample volume, this volume of
the second sample displaces into the chamber 40 the relatively
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small volume of diluent in the tube 14 between the junction of
the tubes 14 and 16 and the outlet of the tube 14, which diluent
has remained in this tube portion from displacement in similar
manner of the fixed volume of the preceding or first sample.
In such displacement of the second sample volume into the
chamber 40, the diluent from the tube 26 serves as a pilot fluid,
and a relatively small amount or volume of such pilot fluid fol-
- lows the second sample volume into the chamber 40 prior to
simultaneous closing of the valves 34 and 45. The sample does
not diffuse to any significant extent when entering the lower
portion of the chamber 40 and, hence, the sample volume and such
diluent entering the chamber 40 with it displace through the
chamber overflow outlet 42 an equivalent amount or volume of
diluent only. In this manner, highly reproducible volumes of
both sample and diluent are achieved with substantial independ-
ence with respect to flow rates. It will be understood from !., ~ .
the foregoing that any desired fixed volume of sample may be
chosen by selection of the length and/or the internal dia-
meter of the portion 14a of the tube 14 between the junction of
the tubes 14 and 16 and the junction of the tubes 14 and 26. The -
last-mentioned tube portion may be rigid and formed of glass, if
desired, for even greater reproducibility.
When the valves 34 and 45 are closed, the mixer motor 73
; is energized by the programmer 22 with consequent mixing of the
liquid contents of the flowcell 38. This mixing results in
hemolysis of the erythrocytes of the sample in the flowcell 38.
During the entry of the sample into the cell 38 and during hemo-
lysis, the sample does not tend to diffuse into the flowcell
48 owing to the relatively very small inner diameter of the flow-
cell 43. Hemolysis in the flowcell 38 enables measurement of
hemoglobin in the sample utilizing the aforementioned photocell 90.-
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The mixer motor 73 is deenergized by the programmer 22.
- The valve 70 then opens, which initiates operation of
the particle counter 78, and the vacuum in the chamber 66 of the
vessel 64 draws the liquid contents of the flowcell 38 through
the flowcell 48 while the white cells or leukocytes of the sample
are counted in the flowcell 48. The diluted sample, emptying
first from the flowcell 38 and then the flowcell 48, flows
through the corresponding arms of the T fitting 50 and through
the tube 62 into the chamber 66. As the liquid level on the
flowcell 48 falls below the light path on the photocell 86 the
presence of air in the flowcell 48 is detected in a conventional
manner by a decrease in light falling on the photocell 86 which
generates a signal to shutdown operation of the particle counter
78. Liquid flowing into the chamber 66 is discharged therefrom
by the action of the pump 18 on the pump tube 68. In this form,
- liquid conveyed by the pump tube 68 is discharged to waste as is
the liquid conveyed by the pump tube 16. ~owever, it will be ap-
- parent that a sample diluted in the chamber 40 in the afore-
mentioned manner may be withdrawn from the chamber 40 through the
pump tube 68 for subsequent treatment and analysis. It will be
.~ understood from the foregoing that when a diluted sample is dis-
charged from the apparatus, the cycle may be repeated with a
third sample of the series in a receptacle similar to the re-
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ceptacle 10 and taking its place with reference to the probe 12.
It is to be understood that the form of the invention
of Fig. 1 may be utilized for proportioning liquids other than
sample and a diluent or reagent. For example, the invention may
be utilized to proportion one unstable reagent with another
reagent or to proportion one unstable diluent with another diluent.
It will also be understood that the invention may be utilized for
platelet and red cell counts of whole blood samples for example,
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and many chemistry tests on blood serum, urine and other liquids.
It will also be apparent that the valves of the apparatus may be
of a type other than pinch valves and may be associated with
rigid tubing instead of compressible tubing.
In the form of Fig. 2, there is shown apparatus for
proportioning liquids in a fluid sample analytical system, com-
prising an aspirating/dispensing probe9 indicated generally at
98, structured of glass, for example. The probe 98 has a lower
tube portion 100 with a lateral outlet 104 spaced upwardly from
an inlet and outlet 102. The portion of probe 98 below the imagi-
nary line 106, defines a second probe chamber, as will appear
hereinafter. Above the line 106, a bulbous enlargement 108 com-
municates with portion 100 and also with an upper tube portion
110, which includes an inlet 112 and an outlet 114. The portion
. of the probe 98 extending between the imaginary line 106 to an -
imaginary line 116 defines a first probe chamber as will appear -
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hereinafter.
The probe outlet 104 is coupled to the inlet of a com-
pressible pump tube 118 which extends through a single-channel
peristaltic pump 120 to waste. Inlet 112 is coupled to com-
pressible pump tube 126, which extends through peristaltic pump -~
128 and has an inlet open to ambient air. Outlet 114 is coupled
to compressible pump tube 132 which extends through a peri-
staltic pump 134 to waste. Pump tubes 118, 126 and 132 provide
flow rates of 0.5 ml~min., 5.0 ml/min., and 5.0 ml/min., when -
the respective pumps 120, 128 and 134 are operated. A pro-
grammer 122 is connected along leads 124, 130 and 136 to se-
lectively energi~e pumps 120, 128 and 134, respectively.
The operation of the form ofthe invention shown in -
Figs. 2-4 will now be described. When probe 98 is immersed in
a liquid receptacle 138, as shown in Fig. 2, programmer 122
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energizes pump 120 to clear outlet 104 of any residua1 liquid.
Subsequently, programmer 122 energizes pump 134, while pu~p 120
remains energized, which aspirates liquid from receptacle 138
to fill probe portions 100, 108 and 110, with excess liquid
flowing to waste through the tubes 118 and 132, respectively. In
this manner, probe portions 100, 108 and llO are washed to re-
move any residue from the previous cycle of operation. Sub-
sequently, pump 134 is deenergized by programmer 122 while the
operation of the pump 120 is continued and probe 98 transferred
from receptacle 138 and immersed in a liquid in receptacle 140,
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shown in Fig. 3. During this transfer, air is aspirated into
probe 98 to further wash the second chamber below line 106,
followed by the liquid from the receptacle 140. Such liquid
fills the second chamber below line 106, any excess being out-
letted to waste along tube 118. In this condition, the first
probe chamber between lines 106 and 116 remains filled with
the previously aspirated liquid from receptacle 138.
The programmer 122 then deenergizes pump 120 and liquid
flow in probe 98 ceases. The probe 98 is then transferred from -
the receptacle 140 to a dispensing position above receptacle 142.
Receptacle 142 may be empty, as shown, or may contain one or
more different liquids in predetermined volumes. The programmer
122 then energizes pump 128 which pumps gas or air along tube 126
and into probe inlet 112, which gas acts as a pilot fluid to
eject the respective contents of the first and second chambers
through probe outlet 102 and into receptacle 142. In so doing,
liquid in the first chamber between lines 106 snd 116 acts as a
pilot fluid to displace liquid in the second probe chamber below
line 106. Pump 128 is deenergized by programmer 122 to end the
cycle of operation. The next cycle may then commènce utilizing
another set of receptacles such as the receptacles 13~, 140 and
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142 previously described.
It is obvious that the relative sizes of the first and
second probe chambers may be varied according to the ratio of
the first and second liquids to be mixed. Such liquids are many
and diverse in character. For the purpose of illustration, the
liquid from receptacle 13~ may be a diluent, while the liquid
from receptacle 140 may be a blood serum sample to be analyzed
for a particular constituent. Also, an appropriate reagent or
reagents for reaction with the sample may be contained in or
added to receptacle 142 prior or subsequent to the dispensing
operation. The reaction product in receptacle 142 may be
measured by conventional techniques, e.g., photometry.
Transfer of the probe 98 between receptacles 138, 140
and 142, shown in Figs. 2-4, and relative movement therebetween
to effect the successive positioning of different sets of
receptacles with respect to probe 98 may be accomplished by auto- -
mated apparatus knoYn in the art. Alternatively, the relative
transfer of probe 98 may be by manipulation of the respective
receptacles while the probe is stationary.
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The form of the invention of Figs. 2-4, like the form of
Fig. 1, provides apparatus and a method for proportioning plural
liquids in highly reproducible volumes, with substantial in-
dependence with respect to the flow rates of such liquids in
liquid sample analysis. The invention includes the utilization
- of plural fixed-volume chambers each with an overflow outlet,
and further includes the use of a pilot fluid to empty a liquid
volume in at least one of such chambers.
While two forms of the invention have been illustrated
in the drawings, it will be apparent, especially to those versed
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in the art, that the invention is susceptible of changes in
details and may take other forms without departing from the
principles of the invention.
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