U.S. patent number 3,804,593 [Application Number 04/369,695] was granted by the patent office on 1974-04-16 for automatic analysis apparatus and method.
This patent grant is currently assigned to Technicon Instruments Corporation. Invention is credited to Morris H. Shamos, William J. Smythe.
United States Patent |
3,804,593 |
Smythe , et al. |
April 16, 1974 |
AUTOMATIC ANALYSIS APPARATUS AND METHOD
Abstract
An automatic analysis apparatus includes an indexible table
supporting a plurality of liquid sample containers, a stationary
reagent liquid container, two off-take tubes, one tube insertable
in a presented thereto sample container, the other tube insertable
in the reagent container, means for concurrently inserting both
tubes repeatedly into their respective containers to provide a
flowing stream of segments of liquid sample interspersed by air
segments, and a similar stream of segments of reagent. These
streams are merged to form stream of liquid and air segments, which
stream of liquid and air segments is passed through the sight
passageway of a flow cell of a colorimeter. A recorder is coupled
to the colorimeter, and may be rendered operational when the sight
passageway of the flow cell is fully occupied by liquid.
Inventors: |
Smythe; William J. (Rye,
NY), Shamos; Morris H. (New York, NY) |
Assignee: |
Technicon Instruments
Corporation (Chauncey, NY)
|
Family
ID: |
23456517 |
Appl.
No.: |
04/369,695 |
Filed: |
May 25, 1964 |
Current U.S.
Class: |
436/53; 356/410;
356/246; 356/432; 422/82 |
Current CPC
Class: |
G01N
35/08 (20130101); Y10T 436/118339 (20150115) |
Current International
Class: |
G01N
35/08 (20060101); G01n 031/00 () |
Field of
Search: |
;23/230,253,259
;73/423,423A ;141/130,131 ;356/181,201,246 ;346/33 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Scovronek; Joseph
Attorney, Agent or Firm: Tedesco; S. P. Rockwell; S. E.
Claims
1. A method of automatic quantitative analysis of a plurality of
liquid samples each disposed in a respective container, wherein
said samples are off-taken by an off-take device and are
transmitted successively as a flowing stream to an analytical
device including a flow cell having a sight passageway, said method
including:
for each sample container in succession, coupling said off-take
device to such sample container, and in alternation therewith, to a
source of an inert fluid immiscible with said liquid samples,
thereby to off-take a segment of each of said liquid samples and
intermediate segments of the inert fluid;
transmitting said segments of the liquid samples and inert fluid as
a flowing stream to said analytical device; and
passing said flowing stream including segments of both the liquid
samples of inert fluid through the sight passageway of the flow
cell, the volume of at least one homogeneous portion of each liquid
sample being at least
2. A method according to claim 1 comprising the further steps
of:
dividing each liquid sample by further inclusions of said inert
fluid which is immiscible with the liquid sample, and
introducing said further inclusions of said inert fluid in the
liquid samples immediately at the point of introduction of the
liquid samples
3. A method according to claim 1 wherein the liquid samples are
stored in respective sample containers and are withdrawn therefrom
by an off-take tube coupled to a pump means, comprising the further
steps of:
alternately immersing and withdrawing said off-take tube into and
from a same sample container to expose said off-take tube to the
atmosphere
4. A method according to claim 2 comprising the further steps
of:
dividing each liquid sample into a leading segment of relatively
short length and a following segment of relatively long length,
said following segment having a volume at least equal to the volume
of the sight passageway of the flow cell,
said leading segment providing a conduit cleansing function and
said
5. A method according to claim 3 comprising the further steps
of:
combining a flowing stream of reagent liquid with said flowing
steam of liquid samples, and
before such combination, dividing said flowing stream of reagent
with inert fluid segments such that upon combination the inert
fluid segments in both
6. Apparatus for the automatic quantitative analysis of a plurality
of liquid samples each disposed in a respective container,
comprising:
an indexible table for supporting said sample containers,
off-take means including an off-take tube coupled to a pump
means,
means for intermittently indexing said table to sequentially
present each of such containers to said off-take means,
means for inserting said off-take tube into a presented thereto
container and alternatively exposing said off-take tube to the
atmosphere;
whereby said pump means draws through said off-take tube a flowing
stream of successive liquid samples spaced apart by intermediate
segments of air;
colorimeter means including a flow cell having a sight passageway
and associated means for analyzing liquid samples passing through
the sight passageway of the flow cell; and
conduit means for passing the flowing stream of successive liquid
samples spaced apart by intervening segments of air through the
sight passageway
7. Apparatus for the automatic quantitative analysis of a plurality
of liquid samples, said apparatus comprising:
a colorimeter including a flow cell having a sight passageway and
an inlet and an outlet through which liquid samples are transmitted
for the quantitative analysis thereof in respect to the same known
ingredient in each sample,
conduit means for the passage of the liquid samples through the
sight passageway of said flow cell,
means for introducing a sample treating liquid and a segmentizing,
inert, immiscible, fluid into said conduit and thereby forming in
said conduit means at a location upstream of said flow cell a fluid
stream containing segments of treated sample liquid spaced from
each other in the direction of stream flow by intervening
immiscible fluid segments,
said conduit means having an outlet connected to said inlet of said
flow cell and devoid of other openings downstream of said upstream
location to pass said fluid stream including treated liquid samples
and said immiscible fluid segments through said sight passageway of
said flow cell for analysis of said treated liquid samples with
said accompanying cleansing of the sight passageway by said
segmentizing fluid; and
means for measuring the optical density of said treated liquid
samples
8. Apparatus according to claim 7 wherein said flow cell has a
sight passageway, and said colorimeter further includes means for
providing a signal indicative of the optical density of said
treated liquid samples passing through said sight passageway;
a chart recorder coupled to said signal providing means; and
means for interrupting the operation of said recorder except when
said sight passageway is fully occupied by a treated liquid sample,
the volume of said treated liquid sample being at least equal to
the volume of said
9. Apparatus according to claim 6 wherein said colorimeter further
includes means for providing a signal responsive to the optical
density of the contents of said sight passageway;
a chart recorder coupled to said signal providing means, and
means for interrupting the operation of said recorder except when
said sight passageway is fully occupied by a sample liquid segment,
the volume of said sample liquid segment being at least equal to
the volume of said
10. A method of automatic quantitative analysis of a plurality of
liquid samples each disposed in a respective container, wherein
said samples are off-taken by an off-take device and are
transmitted successively as a flowing stream to an analytical
device including a colorimeter having a flow cell with a sight
passageway, said method including:
for each sample container in succession, coupling said off-take
device to such sample container, and in alternation therewith, to a
source of an inert gas immiscible with said liquid samples, thereby
to off-take a segment of each of said liquid samples and
intermediate segments of the inert gas;
transmitting said segments of the liquid samples and inert gas as a
flowing stream to said analytical device;
passing said flowing stream including segments of both the liquid
samples and inert gas through the sight passageway of the flow
cell, the volume of at least one homogeneous portion of each liquid
sample being at least equal to the volume of the sight passageway
of the flow cell;
measuring the optical density of the liquid samples passing through
the sight passageway of the flow cell; and
interrupting the operation of said recorder except when said
portion of each sample having a volume at least equal to the volume
of the sight
11. A method of automatic quantitative analysis of a plurality of
liquid samples each disposed in a respective container, wherein
said samples are off-taken by an off-take device and are
transmitted successively as a flowing stream to an analytical
device including a flow cell having a sight passageway, said method
including:
for each sample container in succession, coupling said off-take
device to such sample container, and in alternation therewith, to a
source of an inert gas immiscible with said liquid samples, thereby
to off-take a segment of each of said liquid samples and
intermediate segments of the inert gas;
transmitting said segments of the liquid samples and inert gas as a
flowing stream to said analytical device;
passing said flowing stream including segments of both the liquid
samples and inert gas through the sight passageway of the flow
cell, the volume of at least one homogeneous portion of each liquid
sample being at least
12. A method according to claim 11 comprising the further steps
of:
dividing each liquid sample by further inclusions of said inert gas
which is immiscible with the liquid sample, and
introducing said further inclusions of said inert gas in the liquid
samples immediately at the point of introduction of the liquid
samples into the
13. A method according to claim 12 wherein the liquid samples are
stored in respective sample containers and are withdrawn therefrom
by an off-take tube coupled to a pump means, comprising the further
steps of:
alternately immersing and withdrawing said off-take tube into and
from a same sample container to expose said off-take tube to the
atmosphere between successive immersions into a same sample
container.
Description
This invention relates to improved method and apparatus for
automatic quantitative analysis of a stream of separate discrete
liquid samples especially, but not limited to, the quantitative
analysis of blood and other body fluids with respect to known
substances therein.
The primary object of the present invention is to improve the
precision of quantitative analysis of the samples of liquid. We
have discovered that this important object can be accomplished by
utilizing as much as possible liquid conduits, such as Teflon
tubing, which have non-wetting surfaces instead of wettable
surfaces, and by washing the flow cell between the passage of
successive samples therethrough with one or more bubbles of air or
other gas which is inert to the liquid transmitted through the
conduits and through the flow cell, whereby contamination of one
sample by another is prevented or is negligible. Further, the
sample liquid which is transmitted through the flow cell during the
analysis operation, at which time a record of the analysis is made,
has a volume at least as large and preferably larger than the
volume of the flow cell, so that there is no air in the flow cell
when the liquid analysis operation is being performed. More
specifically, while one or more segments or bubbles of the air or
other gas are introduced into the liquid stream for separating one
sample from another in the apparatus and for washing the conduits
and the flow cell, it is unnecessary to remove said bubbles before
transmission of the treated liquid samples through the flow cell,
since the segmentation of the liquid stream by air bubbles is such
that a sufficient volume of the treated sample liquid is devoid of
air bubbles to enable its analysis as it flows through the flow
cell. By reason of the provision of a volume of non-segmented
treated liquid sample sufficiently large for analysis, namely, a
volume of treated liquid sample at least as large as the volume of
the flow cell, blending of segments of the same liquid sample and
the need for removal of a comparatively large number of air bubbles
are obviated.
Another object of the invention is to provide an apparatus and
method of automatic quantitative analysis of a series of liquid
samples in a flowing stream in such manner that the quantitative
determination in the analysis of each sample is indicated
substantially instantaneously during the flow of the treated sample
through the flow cell, to the extent that the recorder is able to
provide such substantially instantaneous recording, so that the
trace on the recorder chart has a square wave form.
In a herein-disclosed preferred embodiment, the apparatus of our
invention generally comprises automatic, sample supply means for
the provision of the said sample and reagent streams, means to mix
the said streams to promote the desired reactions between the said
samples and the reagent, and means to automatically analyze the
resultant, reacted samples with respect to the relative quantities
of predetermined constituents contained therein. The said sample
supply means are generally similar to those disclosed in the
copending U.S. Pat. No. 3,230,776 to J. Isreeli et al., granted
Jan. 25, 1966, and comprise readily interchangeable, indexable
carrier means for supporting a plurality of individual liquid
sample containers. Separate receptacle means are stationarily
positioned laterally of the said carrier means to provide a supply
of a suitable reagent for mixing with the said samples to enable
the automatic quantitative analysis of the latter with respect to
predetermined constituents thereof. First and second liquid
take-off means are positioned adjacent the carrier means and above
the said reagent receptacle, respectively, and are operative twice,
in unison, through the medium of interconnected electromechanical
control means as each container is indexed into alignment with the
said first take-off means, to concomitantly withdraw two spaced
portions of the liquid from the said container and two,
correspondingly spaced, suitable quantities of reagent from the
said reagent receptacle, respectively, for supply to the said
mixing means in the said sample and reagent streams referred to
hereinabove. The said mixing means comprise a junction block for
the joinder of the two streams, and a mixing coil, each of which is
constructed of a material of natural anti-wetting properties to
inhibit contamination of one sample by the residue of a preceding
sample; while the said automatic analysis means comprise
colorimetric analysis apparatus and analysis result recording means
operatively associated therewith.
The above and other objects, features and advantages of our
invention are believed made clear by the following detailed
description thereof taken in conjunction with the accompanying
drawings wherein:
FIG. 1 is a top plan view, with parts in section and portions cut
away for purposes of illustration, of the sample supply means of
the apparatus in our invention;
FIG. 2 is a vertical sectional view taken along line 2--2 of FIG.
1;
FIG. 3 is an isometric projection of the sample and reagent
take-off means of our invention in a first position thereof;
FIG. 4 is an enlarged top plan view of the sample and reagent
take-off means of our invention in a second position thereof;
FIG. 5 is a cross sectional diagram of the sample and reagent
supply lines illustrating the relative positions therein of the
respective, correspondingly spaced, sample and reagent streams;
and
FIG. 6 is a diagrammatic illustration of the apparatus of our
invention.
Referring now to the drawings, and particularly to FIGS. 1-4, the
sample supply means of the herein-disclosed preferred embodiment of
our invention comprise essentially a housing 11; with indexable
turntable assembly 12, turntable drive means 13, sample and reagent
take-off assemblies 14 and 16, respectively, take-off assembly
actuating mechanisms 17, timing mechanism 18, and reagent
receptacle 20, positioned thereon or therewith in the depicted
manner.
In the operation of the sample supply means, a plurality of
liquid-sample containing cups 23 are mounted as shown in a
generally circular array upon the turntable assembly 12 and
successively positioned in turn thereby, through the operation of
the turntable drive mechanism 13, to positions in alignment with
the sample take-off assembly 14. As each said cup is indexed into
the said aligned position, the respective sample and reagent
take-off assemblies are actuated, by actuating mechanism 17 under
the control of timing mechanism 18, with the former functioning to
withdraw a portion of the sample from the said cup, and the latter
functioning to withdraw a suitable quantity of reagent of
corresponding extent, from the reagent receptacle 20. The
respective sample and reagent take-off assemblies are then
momentarily withdrawn from the said sample cup and reagent
receptacle, and then returned thereto for the withdrawal therefrom
of a second portion of the same sample from the same sample cup,
and another suitable quantity of reagent of corresponding extent
from the reagent receptacle. At the conclusion of this second
sample and reagent withdrawal, the sample take-off assembly 14 is
withdrawn from the said sample cup, and the turntable assembly 12
indexed one cup position to present the next succeeding sample cup
in position for withdrawal of the two sample portions therefrom by
the said sample take-off assembly 14. Operation continues in this
manner until two separate portions of each of the samples have been
withdrawn from each of the sample cups in the manner described
above. Alternatively, the reagent take-off assembly 16 may be
eliminated and the reagent supplied as a constant stream thereof as
described hereinbelow.
Turning now in greater detail to the structure of the sample supply
means, the turntable assembly 12 comprises a generally circular
plate 21 incorporating a generally circular array of cup mounting
holes formed adjacent the periphery thereof. The sample cups 23 are
removably positioned within these holes by insertion therewithin
and include canted bottom portions, in the manner made clear in
FIG. 2, whereby any appreciable quantity of liquid within the cup
will tend to accumulate at the outer cup edge for convenient
removal therefrom by the take-off assembly 14.
The turntable plate 21 is detatchably secured, in a manner made
clear in the said co-pending Isreeli et al. application referred to
hereinabove, to rotatable support shaft 24, whereby rotation of the
said shaft will result in corresponding rotation of the said plate.
A Geneva gear plate 32, including notches 35 formed therein as
shown, is also secured to the said support shaft, whereby driven
rotation of the said Geneva gear plate will result in
correspondingly driven rotation of the said support shaft and
turntable plate, respectively.
The Geneva gear plate 32 is in turn driven by the engagement
therewith of Geneva cam 34 in the manner made clear by FIGS. 1 and
2. The configuration of the said cam 34 is such that every complete
revolution thereof will function, in a well-known manner, to
advance the Geneva gear plate 32 one notch and then maintain the
plate stationary as positioned until the leading edge 36 of the cam
driving portion 30 enters the next succeeding notch 35 to repeat
the driving process. There is one notch 35 formed in the periphery
of Geneva gear plate 32 for each of the array of sample cup
mounting holes formed on turntable plate 21, whereby may be
appreciated that each complete revolution of Geneva cam 34 will
function to advance the turntable plate 21 one sample cup position
to in turn index a new sample cup into alignment with the sample
take-off means 14. The Geneva cam 34 is fixedly mounted as shown
upon drive shaft 37 of drive motor 38, and is rotatably driven
thereby to drive the Geneva gear plate 32 and turntable plate 21 as
described hereinabove.
A drive gear 39 is also fixedly secured to the motor drive shaft
37, and a driven gear 41 mounted for rotation adjacent thereto and
enmeshed therewith as shown, whereby rotation of gear 39 will
result in driven rotation of gear 41. A connecting link 42 is
pivotally attached as shown adjacent the periphery of driven gear
41 in the manner indicated at 44 in FIG. 1. In the hereindisclosed
preferred embodiment, the relative sizes of gears 39 and 41,
respectively, are chosen so that one complete revolution of gear 39
will result in two complete revolutions of gear 41.
Each complete revolution of gear 41 results in turn, through the
action of connecting link 42 and take-off assembly support post 81
in the manner made clear in the said copending Isreeli et al.
application referred to hereinabove, in the movement of the sample
and reagent take-off assemblies 14 and 16, respectively, from the
positions thereof depicted in solid lines in FIG. 3 to the
positions thereof depicted in phantom in the said Figure, and back
to the first-mentioned position thereof. Thus may be understood
whereby one complete revolution of motor drive shaft 37 will result
first in the advancement of turntable plate 21 one cup position,
through the action of Geneva cam 34 and Geneva gear plate 32,
followed by two successive movements of the take-off assemblies 14
and 16 from the positions thereof depicted in solid lines in FIG. 3
to the positions thereof depicted in phantom in the said Figure,
and back to the first-mentioned positions thereof.
The sample take-off assembly 14 comprises a metal crook 75, shaped
as shown, with sample supply line 76, preferably of polyethylene
tubing, extending therethrough. The reagent takeoff assembly 16
comprises a metal crook 77, shaped as shown, with reagent supply
line 78, preferably of polyethylene tubing, extending therethrough.
Each of the metal crooks 75 and 77 extend as shown through holes
provided therefor in the crook support bar 79 and are maintained
properly positioned therewithin by set screws 80 bearing
thereagainst. The said crook support bar 79 is in turn positioned
atop crook support post 81 and movable therewith, whereby movement
of the said support post will result in corresponding movement of
the inlet end of the sample and reagent lines 76 and 78,
respectively, between the respective positions thereof depicted in
FIG. 3. A slot 82 is provided as shown in the housing 11 to enable
movement of the crook support post 81 relative thereto. Generally
speaking, it may be noted that the respective take-off assemblies
14 and 16 are each movable, through the movement of support post
81, in the same vertical plane. The reagent receptacle 20 is
positioned as shown in any convenient manner on the housing 11, as,
for example, by attachment screws 83 extending therebetween. The
said receptacle comprises hollow interior portions 89 and 90 with
inlet and outlet conduits, 85 and 86, respectively, extending
therefrom. A dam 87 extends as shown in FIG. 1 between the said
hollow interior portions of the receptacle whereby reagent may
enter the receptacle through inlet 85, spill over the dam 87 and
flow from the receptacle through outlet 86. Outlet 86 is of larger
internal diameter than inlet 85 whereby may be appreciated that the
reagent will never overflow from the said receptacle, or accumulate
to any appreciable degree within hollow interior portion 90
thereof.
In a first position of the respective sample and reagent take-off
assemblies, i.e., that depicted in solid lines in FIG. 3, the inlet
end of sample-supply line 76 is exposed to the atmosphere in the
space immediately adjacent the reagent receptacle 20, while the
inlet end of reagent supply line 78 is exposed to the atmosphere
within the hollow interior portion 90 of the said receptacle. Thus,
with reduced pressure conditions maintained in the said lines in
the manner described in detail herein below, air only will be
aspirated through the said lines with the said assemblies thusly
positioned. In a second position of the said take-off assemblies,
i.e., that depicted in phantom in FIG. 3, and normally in FIGS. 2
and 4, the inlet end of the sample supply line 76 is positioned
within the sample liquid in the cup 23 positioned in alignment
therewith, while the inlet end of the reagent supply line 78 is
positioned within the reagent contained within hollow interior
portion 89 of the receptacle. Thus, reduced pressure conditions
within the said supply lines will result in the aspiration of
liquid sample through the former, and reagent through the latter.
Since the said supply line inlet ends always move in unison as made
clear above, it may be understood whereby the extent, taken along
the respective axes of the lines, of sample and reagent, or air,
quantities aspirated thereby will always correspond.
The timing mechanism 18 comprises a timing cam 102 driven at
constant speed by a non-illustrated, constant speed timer motor
through shaft 104. Notches 105 and 107 are formed as shown in the
periphery of the timing cam. A two-position switch 106 is
positioned as shown on the housing 11 adjacent the timing cam, and
includes a switch actuator 108 which extends into contact with the
periphery of the cam in such a manner that the said switch is moved
to one position thereof when actuator 108 rides on the un-notched
periphery of the cam, and to the second position thereof when the
said actuator rides within one of the notches 105 or 107. The
extent and placement of the said notches 105 and 107 control,
through switch 106 and operatively associated control circuitry not
illustrated or described in detail in this application, the
operation of the drive motor 38 and thus of the turntable and
respective sample and reagent take-off assemblies. This control
circuitry, and the manner of operation thereof, is described in
detail in the said copending Isreeli et al. application. Suffice,
however, for purposes of this application to note that, in
accordance with the presently preferred form of the invention, the
entry of switch actuator 108 into a notch will result in the
movement of the sample and reagent take-off assemblies to the
positions thereof depicted in solid lines in FIG. 3, whereby air
only will be aspirated through the respective sample and reagent
supply lines 76 and 78 during the entire time that actuator 108
remains in a notch 105 or 107. Further, the entry of the switch
actuator into notch 105 will result in the advancement of the
turntable plate 21 one cup position, through the action of Geneva
cam and plate 34 and 32, to position a new sample cup in alignment
with sample take-off assembly 14. Conversely, when actuator 108
rides out of either notch 105 or 107 on to the unnotched periphery
of the timing cam, this will result in the movement of the sample
and reagent take-off assemblies to the positions thereof depicted
in FIG. 2, whereby sample will be aspirated through the sample
supply line 76 and reagent through the reagent supply line 78.
Referring now to FIG. 5, the sample supply line 76 and reagent
supply line 78 are depicted in cross section to illustrate the
corresponding extent and placement of the respective air, sample,
and reagent segments aspirated therethrough through the use of a
timing cam 102 of the general configuration depicted in FIG. 1.
Segment S of sample and R of reagent represent respectively the end
of the second-aspirated segments of a preceding sample, and the
correspondingly aspirated reagent segment. Air segments A.sub.1
would then be aspirated through the sample and reagent supply lines
as the switch actuator 108 rode within timing cam notch 105 to
position the sample and reagent take-off assemblies in the manner
depicted in solid lines in FIG. 3 in the manner set forth above.
Concurrently therewith, the turntable plate 21 would be advanced
one cup position to present a new sample cup 23 in alignment with
the sample take-off assembly 14. As switch actuator 108 rides out
of notch 105 onto the unnotched peripheral portion 109 of the
timing cam 102, the sample and reagent take-off assemblies are
moved to the positions thereof depicted, for example, in FIG. 2
whereby the first-aspirated segment S.sub.1, of the new sample, and
the correspondingly aspirated reagent segment R.sub.1 are provided.
As cam portion 109 completes its travel beneath actuator 108, the
latter rides into notch 107 whereby the respective take-off
assemblies are again returned momentarily to the positions thereof
depicted in solid lines in FIG. 3 and segments of air A.sub.2
aspirated therethrough. As soon as actuator 108 rides out of notch
107 onto the un-notched portion 112 of the timing cam, the
respective take-off assemblies are returned to the position thereof
of FIG. 2. Since no movement of the turntable plate 21 occurred
during the aspiration of air segments A.sub.2, the same sample cup
23 is still in alignment with the sample take-off assembly 14,
whereby the second-aspirated segment S.sub.2 of the said sample,
and the correspondingly aspirated reagent segments R.sub.2, are
provided. The entire process is then repeated as the switch
actuator reenters notch 105 to return the take-off assemblies to
the positions thereof of FIG. 3 to aspirate air segments A.sub.3,
advance the turntable another cup position to position a new sample
cup 23 in alignment with the sample take-off assembly, whereby the
first and second-aspirated segments S.sub.4 and S.sub.5 of the new
sample, and the correspondingly aspirated reagent segments R.sub.4
and R.sub.5, spaced as shown by air segments A.sub.4, may be
provided in the same manner. In accordance with the presently
preferred form of the invention, reagent supply line 78 is chosen
of greater inner diameter than the sample supply line 76, whereby
each of the reagent segments will be of greater volume than the
correspondingly aspirated sample segment, although of the same
lateral extent within the said supply lines.
In FIG. 6 a proportioning pump is indicated diagrammatically at
130, and may be of the nature disclosed in U.S. Pat. No. 2,893,324.
The said pump comprises resiliently flexible pump tubes 132 and 134
which are connected as shown to the sample and reagent supply lines
76 and 78, respectively, and have substantially the same internal
diameters as the said lines. In pumps of this nature, the said pump
tubes are compressed progressively along their lengths by
non-illustrated rollers which are moved in compressing engagement
with the tubes longitudinally thereof. The relative quantities of
fluids pumped through the said tubes may thus be understood to
depend upon the respective internal diameters thereof since the
tubes are longitudinally compressed, at the same linear speed, by
the said rollers.
The pump tubes are connected as shown by lines 136 and 138 to flow
passages 142 and 144 of junction block 140. The said junction block
is preferably of a material of very tight molecular structure with
natural non-wetting properties, as for example "Kel-F," whereby the
formation of a residue of a sample flowing therethrough which could
contaminate the next succeeding sample, is effectively inhibited.
Flow passages 142 and 144 merge within the junction block into flow
passage 146, whereby may be understood the manner in which the
correspondingly aspirated sample and reagent segments, described
above in conjunction with the description of FIG. 5, may be joined
together to form a larger segment of sample and reagent. This
joining together of the said correspondingly aspirated sample and
reagent segments of course requires that the flow path lengths from
the inlet ends of the respective sample and reagent supply lines,
to the juncture of flow passages 142 and 144 at flow passage 146,
be substantially equal because the said segments flow through the
said supply lines and pump tubes at the same velocity as described
above. To this effect, reagent supply line 78 is depicted as
somewhat curved to illustrate the need for the equalization of the
said flow path lengths.
A mixing coil 150, preferably of Teflon for the same non-wetting
reasons discussed above, is provided and connected to flow passage
146 of the junction block 140 by line 148 extending therebetween.
The said mixing coil may, if desired, be placed in a heating bath,
and functions to thoroughly mix, and promote the desired reaction
between, the combined sample and reagent segments resulting from
the juncture of flow passages 142 and 144 in the junction
block.
Colorimetric analysis apparatus are generally indicated at 159 and
comprise a source of light 156, collimating lenses 157 and 158,
optical filter 160, flow cell 154, light responsive detecting means
162, and a chart recorder operative to record analysis results
connected to the detecting means through line 164. In accordance
with a presently preferred form of our invention, the said
colorimetric analysis apparatus may be similar to those disclosed
in U.S. Pat. No. 3,031,917.
The said flow cell 154 is connected to the outlet of the mixing
coil 150 by line 152, whereby the reacted sample segments may be
flowed therethrough for colorimetric analysis, and the results
thereof by stylus 167 on recorder chart 168 in a manner made clear
in the said U.S. Pat. No. 3,031,917.
The supply of each sample in two separate segments functions to
effectively inhibit the contamination of a sample by the residue of
a preceeding sample. Thus, with further reference to FIGS. 5 and 6,
it may be understood whereby sample segment S.sub.1 will function
to remove any residue from segment S of the preceeding sample from
the interior walls of sample supply line 76, pump tube 132,
connecting line 136, and flow passage 142 of the junction block
140. After combination of sample segment S.sub.1 and reagent
segment R.sub.1 in flow passage 146 of the junction block, the
resultant combined sample and reagent segment S.sub.1 R.sub.1 will
function to remove any residue of the preceeding combined segment
SR from flow passage 146, connecting line 148, mixing coil 150,
connecting line 152, and flow cell 154. Thus may be understood
whereby the smaller or first-aspirated segment of each sample, and
the air segments provided on either side thereof, function as
cleansing agents to prevent the contamination of the succeeding
larger, second-aspirated segment of the same sample, by the residue
of a preceeding sample remaining in the apparatus. Thus, the supply
of a segment of a wash liquid after each sample, or of additional
air to further segment each sample or wash liquid segment to
increase the cleansing power thereof, is made unnecessary. Further,
the elimination of the air segmentation of each sample segment
makes unnecessary the provision of means to remove the air prior to
the introduction of the sample segment to the flow cell for the
colorimetric analysis thereof.
In accordance with a presently preferred form of our invention, it
is only the larger, or second-aspirated segment of each sample, as
for example sample segments S.sub.2 or S.sub.5 of FIG. 5, which are
subjected to colorimetric analysis for analysis result recording
purposes; the smaller or first-aspirated sample segments, and
adjacent air segments, being provided primarily for the cleansing
effect thereof as described above. To this effect, switch means 175
may be provided, if preferred, in electrical line 164 and
controlled, as indicated, by the operation of the sample supply
assembly, to complete the circuit from the detecting means 162 to
the chart recorder 166 only when a said larger or second-aspirated
sample segment, mixed and reacted of course with the
correspondingly aspirated reagent segment, flows through the flow
cell. Alternatively, the supply of power to the colorimetric
analysis apparatus as a whole may be effected only when a larger
sample segment flows through the flow cell.
In the analysis operation, there is no air or other gas in the flow
cell and during that operation the volume of sample liquid, treated
for colorimetric analysis, which is transmitted through the flow
cell, is at least as large as and preferably larger than the volume
of the flow cell. Each volume of reagent-treated sample liquid is
in an intermediate position in the flowing stream between a leading
gas bubble and a trailing gas bubble as the stream flows through
the conduit to the flow cell for said analysis operation, and said
gas bubbles are disposed, respectively, between said volume of
treated sample liquid and a down stream portion of the same treated
sample liquid and between said volume of treated sample liquid and
an upstream portion of the same treated sample liquid. During the
flow of this volume of reagent-treated liquid sample, free of air
or other gas, through the flow cell, the quantitative indication of
the analysis by the trace of the recorder stylus on the chart paper
reaches its peak value almost instantaneously, i.e., as fast as the
stylus can move, so that the continuous trace on the chart paper,
corresponding to the seriatim analyses of a series of treated
sample liquids in the stream, is of a square wave form.
The use of an air-segmented supply of reagent is especially
desirable in cases wherein the available quantity of each sample is
very limited, as for example in the case of automatic analysis on
the blood of infants. In these cases, since the supply of sample is
small, the internal diameter of sample supply line 76 must also be
small whereby it becomes quite difficult to introduce sufficient
air through the said supply line to properly separate the
respective sample segments through to the analysis apparatus after
the combination thereof with the reagent. Thus, the major portion
of the air for sample segment separation is introduced as the air
segments in the reagent supply line 78 as described above.
In cases, however, wherein the available quantity of each sample is
not strictly limited, it is possible to use a sample supply line 76
of sufficient internal diameter to provide air segments of
sufficient extent to properly separate the sample segments, even
after the mixture thereof with reagent. In such cases, the air
segmenting of the reagent supply stream is not necessary whereby
the reagent take-off assembly 16 may be eliminated and the inlet
end of reagent supply line 78 merely submerged in any convenient
source of reagent, as, for example, reagent receptacle 20, and a
continuous stream of reagent supplied through the said supply line,
pump tube 134 and connecting line 138, to flow passages 144 and 146
of the junction block 140 for combination therewithin with the
respective air and sample segments supplied thereto through
connecting line 136.
It will be understood that all of the tubing except the resiliently
compressible pump tubes, here indicated at 132 and 134, are made of
Teflon which, as is well known, is non-wetting. This non-wetting
characteristic is maintained permanent in the operation of the
apparatus by the absence of wetting agents in the sample liquids
and by the omission from the sample treating reagents of any
wetting agent. As the pump tubes are comparatively small in length
as well as in internal diameter and are made of Tygon, there is no
significant residual deposit of sample on the inner surfaces of the
pump tubes, especially since each sample which flows through the
pump tube is followed by one or more bubbles of air or other gas
inert to the sample liquid as above indicated.
While we have shown and described the preferred embodiment of the
invention, it will be understood that the invention may be embodied
otherwise than as herein specifically illustrated or described, and
that certain changes in the form and arrangement of parts and in
the specific manner of practicing the invention may be made without
departing from the underlying idea or principles of this invention
within the scope of the appended claims.
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