U.S. patent number 3,811,780 [Application Number 05/357,063] was granted by the patent office on 1974-05-21 for chemical analysis cuvette.
This patent grant is currently assigned to Abbott Laboratories. Invention is credited to Max D. Liston.
United States Patent |
3,811,780 |
Liston |
May 21, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
CHEMICAL ANALYSIS CUVETTE
Abstract
Improved components, such as a cuvette, are disclosed in the
specification.
Inventors: |
Liston; Max D. (Irvine,
CA) |
Assignee: |
Abbott Laboratories (North
Chicago, IL)
|
Family
ID: |
26831017 |
Appl.
No.: |
05/357,063 |
Filed: |
May 3, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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133081 |
Apr 12, 1971 |
3748044 |
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Current U.S.
Class: |
356/246;
73/866.1; 356/409; 73/290R; 356/244; 422/562 |
Current CPC
Class: |
G01N
21/03 (20130101); G01N 2035/00396 (20130101); G01N
2035/0448 (20130101) |
Current International
Class: |
G01N
21/03 (20060101); G01N 35/04 (20060101); G01N
35/00 (20060101); G01j 003/46 (); G01n
001/10 () |
Field of
Search: |
;250/218
;356/180,244,246 ;73/423A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wibert; Ronald L.
Assistant Examiner: McGraw; V. P.
Attorney, Agent or Firm: Molinare, Allegretti, Newitt &
Witcoff
Parent Case Text
RELATED APPLICATION
This application is a Division of my application Ser. No. 133,081
filed Apr. 12, 1971, now U.S. Pat. No. 3,748,044, entitled "Digital
Chemical Analysis Apparatus".
Claims
1. In a chemical analyzer, an improved cuvette comprising:
integrally formed means for defining individual compartments
adapted to hold specimens, said compartments being arranged to pass
through a line defining a closed curve having a central axis;
and
window means for transmitting radiant energy through at least some
portions
2. A cuvette, as claimed in claim 1, and further comprising
ventilation means for defining an opening within said curve for
allowing the passage
3. A cuvette, as claimed in claim 1, wherein a common plane
intersects each
4. A cuvette, as claimed in claim 1, wherein the window means
associated with each compartment comprises opposed planar members
that are parallel
5. A cuvette, as claimed in claim 1, wherein the compartments
comprise sidewall means and wherein the window means are formed
integrally with the
6. A cuvette, as claimed in claim 1, wherein each compartment
comprises
7. A cuvette, as claimed in claim 1, wherein the window means
are
8. A cuvette, as claimed in claim 7, wherein the window means
are
9. A cuvette, as claimed in claim 1, wherein the compartments
are
10. A cuvette, as claimed in claim 9, and further comprising
temperature control means for maintaining the specimens at a
predetermined temperature comprising:
a bath solution in which the sidewall means are at least partially
immersed so that the bath solution enters the air spaces between
the compartments; and
11. A cuvette, as claimed in claim 2, in combination with
additional analyzing apparatus comprising a source of radiant
energy located within the area bounded by a vertical projection of
said line defining a closed
12. Apparatus, as claimed in claim 11, and further comprising:
rotation means for rotating the cuvette in relationship to the
radiant energy source, whereby the radiant energy sequentially
passes through the window means in each of said compartments;
and
means for passing air over the source and through said opening,
whereby the
13. Apparatus, as claimed in claim 12, wherein the source is
aligned so that the radiant energy is transmitted perpendicular to
the surface of the window means at some time during the operation
of the rotation means.
Description
BACKGROUND OF THE INVENTION
This invention relates to a chemical analysis cuvette, and more
particularly relates to a cuvette which enables the analysis of
substances by radiant energy.
In order to rapidly analyze the concentration of a particular
substance present in a chemical specimen, such as blood, chemists
are placing increasing reliance on various types of machines. Such
machines devised in the past may be divided into at least the
following types:
1. Blood gas analyzers;
2. Prothrombin time determining systems;
3. Flow systems;
4. Electromechanical methods not related to colorimetry; and
5. Monochromatic servomechanism systems.
Although such machines have somewhat reduced the labor involved in
performing chemical analysis, they have exhibited many deficiencies
that have limited their overall usefulness. One such deficiency is
the difficulty of loading and cleaning the specimen dispensers and
cuvettes of prior art systems. Such difficulties are particularly
pronounced when flow-through cuvettes are utilized. These cuvettes
provide a single chamber for analyzing multiple specimens that must
be purged with a relatively large volume of specimen fluid each
time a new specimen is introduced into the chamber. Prior art
systems also fail to mix the specimen and reagent with the degree
of accuracy desired by most chemists.
In order to overcome the difficulties of the prior art devices,
applicant's cuvette means preferably comprises integrally-formed
sidewalls and spacer means that define compartments in which
specimens may be introduced. Opposed, planar window means for
transmitting radiant energy may also be provided in the
compartments so that the specimens may be analyzed with a degree of
accuracy unattained by systems employing curved windows, such as
test tubes. By integrally fabricating the sidewall and spacer means
from the plastic material described herein, the cuvette means is
rendered disposable, thereby eliminating the most common cause of
specimen contamination.
DESCRIPTION OF THE DRAWINGS
These and other advantages and features of the present invention
will hereinafter appear for purposes of illustration, but not of
limitation, in connection with the accompanying drawings, in which
like numbers refer to like parts throughout, and in which:
FIG. 1 is a perspective view of a preferred form of apparatus made
in accordance with the present invention;
FIG. 2 is a top plan view of a preferred form of cuvette assembly
made in accordance with the present invention;
FIG. 3 is a cross-sectional view taken along line 3--3 of FIG.
2;
FIG. 4 is a side elevational view of the cuvette assembly shown in
FIG. 2;
FIG. 5 is a cross-sectional, fragmentary, partially schematic view
showing the cuvette assembly, carrousel assembly, cycling
apparatus, positioning apparatus, and a portion of the analyzing
apparatus of the preferred embodiment;
FIG. 6 is a front elevational view of a preferred form of position
encoding apparatus made in accordance with the present invention;
and
FIG. 7 is a fragmentary, partially cross-sectional side elevational
view of a preferred form of carrousel advance apparatus made in
accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, a preferred system for analyzing
chemical specimens made in accordance with the present invention
basically comprises a cuvette assembly 30; a carrousel assembly
110, including a cycling assembly 168; a dispenser assembly 200;
and a console 502 that includes analyzing apparatus, a processing
circuit and a memory.
Referring to FIGS. 1-4, cuvette assembly 30 provides 32
compartments in which 32 separate chemical specimens may be mixed
and held for analysis. The assembly is integrally formed from an
acrylic plastic material that transmits ultraviolet light, such as
Rohm and Haas Plexiglas V(811)-100UVT. Applicant has found that
this material offers a number of advantages. It is relatively
inexpensive, and therefore enables the cuvette to be disposed of
after use. In addition, the described acrylic plastic offers
excellent optical properties for the transmission of ultraviolet
light which are not provided by many other acrylic plastics.
Referring to FIGS. 2-4, cuvette assembly 30 comprises a slanting,
inner sidewall 32 having an inner surface 34 and an outer surface
36. Cuvette assembly 30 also comprises a slanting, outer sidewall
40 having an inner surface 42 and an outer surface 44. Sidewalls 32
and 40 are each slanted at an angle of 15.degree. from a vertical
plane. Applicant has found that this is the minimum angle required
to prevent specimen fluid from splashing out of the cuvette as it
is being discharged therein.
Another portion of cuvette assembly 30 comprises a cylindrical
collar 50 having an upper edge 52, a lower edge 54, and a central
axis 56. Collar 50 defines a ventilating opening 55 that allows the
passage of air.
Assembly 30 further comprises a positioning lip 92 attached to
outer sidewall 40 in the manner shown. Lip 92 has notches, such as
notches 94, 96 that are equally spaced between each other and are
located along a center line radius of a compartment.
Spacers 58 are integrally formed with the sidewalls in a
fluid-tight manner to form 32 separate compartments 60-91. The
compartments lie along a line defining a circle. The lower portion
of each spacer is split into two sections 57,59 that separate each
of the compartments by an air space 53. This feature enables
several cuvettes to nest on top of each other, thereby reducing the
space required for storage. In addition, this air space allows the
fluid of an incubating device to separately flow around each
compartment, thereby reducing the time required to bring the
specimens up to temperature. This feature will be described in more
detail later. Each of the compartments is adapted to hold a
specimen to be analyzed. The lower portion of each compartment is
fitted with a bottomwall that is integrally formed with the
adjacent spacers and sidewalls in a fluid-tight manner. Exemplary
bottomwalls 48 have curved upper surfaces 49 that cause fluid
ejected into the compartments to engage in a swirling motion that
aids mixing.
Each of the compartments 60-91 is identical and may be understood
from exemplary compartments 67 and 83 shown in FIG. 3. Compartment
67 comprises the sidwalls and bottomwalls described previously. In
addition, compartment 67 comprises flat, planar portions 98 and 100
that form a window section 38. Likewise, compartment 83 comprises
the sidewall and bottomwall described previously. In addition, it
comprises flat planar portions 102 and 104 that form a window
section 46. It should be noted that portions 98, 100 are opposed
planar members that are parallel to each other. Likewise, portions
102, 104 are also opposed planar members that are parallel to each
other and to portions 98, 100. As can be seen in FIGS. 2-4, the
flat planar portions forming the window sections lie in a common
plane and are integrally formed with the bottomwall and sidewalls.
It should be noted that sidewalls 32 and 40 are each 0.040 inches
thick, and that the distance between planar portions 98, 100 and
the distance between planar portions 102, 104 is in each case
exactly 1 centimenter.
As will be described in more detail later, this arrangement of
window sections provides an accurate path-length for a radiant
energy analyzing beam not found in the test tube cuvettes employed
in some systems. Moreover, since the entire cuvette assembly is
made from a relatively inexpensive plastic, it may be disposed of
after a single use so as to prevent contamination from previous or
improper washing. The disposability of the cuvette is very
important, since it eliminates the necessity of using large volumes
of reagent to wash the previous sample from a flow-through cuvette.
By using the cuvette assembly described herein, the same
compartment is used as a reaction chamber and radiant energy
analyzing chamber, thereby achieving economy of operation and a
more compact system than would be otherwise possible.
Referring to FIGS. 1 and 5, carrousel assembly 110 comprises a
cylindrical base member 112 that supports platforms 114, 115.
Platform 114 carries cylindrical support column 116 through which
air is circulated by a fan 118 for cooling purposes. A cylindrical
outer column 120 is carried by the top of column 116.
An incubator assembly 122 comprises a generally toroidal bath
chamber 124 which is formed by a hollow receptacle 125 comprising a
cylindrical inner wall 126 and a cylindrical outer wall 128. Wall
126 is integrally formed with column 120. Walls 126 and 128 are
fabricated from a good thermal conducting material such as aluminum
or copper. Windows that readily pass radiant energy in order to
accommodate analyzing apparatus described hereafter are located in
walls 126 and 128. Bath chamber 124 is filled with water to level A
shown in FIG. 5. The water is heated to a predetermined temperature
by a heater element 129, and the heater element is controlled by a
thermistor 131 and a manually adjustable control switch (not
shown). As shown in FIG. 5, the incubator is used in order to
maintain the specimens held in the cuvette compartments at a
predetermined temperature. As previously described, the cuvette
compartments are separated so that the water of incubator assembly
122 freely flows adjacent each specimen. Applicant has found that
this arrangement brings the specimens up to temperature faster and
holds the specimens at a more uniform temperature than has
heretofore been possible.
Still referring to FIGS. 1 and 5, assembly 110 is provided with a
movable positioning platform 130 comprising a cylindrical skirt 132
and a ring-shaped test tube retainer 134. The retainer comprises a
horizontal ring member 136 that is provided with holes for
receiving 32 test tubes commonly designated by the number 138, and
including exemplary test tubes 140, 141. Each of the test tubes
lies along a radius common to a corresponding cuvette compartment.
The retainer also comprises a vertical ring-shaped retainer 142.
According to the preferred embodiment of the invention, the test
tubes are used to hold chemical samples prior to the time they are
mixed with a suitable reagent to form a specimen for analysis. The
tubes are biased against retainer 142 by resilient spring clips,
such as exemplary clips 143, 144. The clips are mounted on skirt
132.
Positioning platform 130 also comprises a raised, ring-shaped
portion 146 that carries on its underside a circular positioning
member 148 bearing detents. Member 148 is provided with one detent
opposite each test tube and corresponding cuvette compartment, so
that each specimen may be accurately located in a predetermined
analyzing position during the analysis procedure. The entire
positioning platform is rotatably mounted on the platform 115 by
means not shown. The inner edges of platform 130 are fitted with
guides, such as guides 149, 150 that comate with the notches of lip
92 of cuvette assembly 30. By using the guides, the cuvette
assembly is precisely located on the platform and is rotatable
therewith.
Cylindrical skirt 132 comprises 32 sets of five coded holes that
are drilled adjacent a radial line extending from each cuvette
compartment. An exemplary set of 152 of such coded holes are shown
in FIG. 6. Referring again to FIG. 5, light is transmitted through
the coded holes to a plurality of stationary phototransistors 154
by a light pipe 156. As explained in more detail later, the coded
holes are used to generate a binary identity code that uniquely
identifies each test tube and corresponding cuvette compartment
that is moved into the analyzing position. That is, each of the
test tubes and corresponding cuvette compartments is identified by
a different arrangement of coded holes which can be recognized and
used to perform certain machine functions. The manner in which
cells 154 are arranged in order to recognize the hole binary code
is well-known to those skilled in the art.
As shown in FIG. 5, a test tube detection assembly 158 is held in a
cabinet 160 that is located one position ahead of the analyzing
position. The assembly comprises a pendulum 162 pivoted around a
rod 164. The pendulum normally swings into the path of test tubes
138, and in that position, causes a mercury switch 166 to be
closed. When a test tube is positioned opposite assembly 158,
pendulum 162 is moved to the position shown in FIG. 5, thereby
causing switch 166 to open. Assembly 158 is arranged so that the
normal operation of the system is interrupted if no test tube is
present at a particular position in ring member 136.
Carrousel assembly 200 also comprises a cycling assembly 168 shown
in FIG. 7. Assembly 168 comprises a solenoid 170 that operates an
actuator arm 172 comprising an upper arm 171 and a lower arm 173
that pivot about a bearing 174. Assembly 168 also comprises a
metallic bellows 176 that is normally filled with oil. A flexible
hat-section 177 is located above the bellows and is connected
thereto by a flapper valve 178 that controls the movement of oil. A
spring 180 mounted on actuator arm 172 biases a roller arm 182 in
an upward direction (as shown in FIG. 7). A roller 184 is rotatably
mounted at the outer end of roller arm 182 and is biased into
contact with the detents of positioning member 148, such as
exemplary detents 185, 186. As previously described, positioning
member 148 is rigidly attached to positioning platform 130 on which
cuvette 30 is carried. The biasing action of spring 180 ensures the
precise positioning of the positioning platform at all times.
The cycling assembly operates as follows. When solenoid 170 is
activated, it forces upper arm 171 to the right (as shown in FIG.
7), and forces lower arm 173 upward, thereby compressing bellows
176 in an upward direction. This force is resisted by the bellows
which is filled with oil. In order to relieve the oil pressure,
flapper valve 178 opens, thereby permitting oil from the bellows to
flow freely into flexible hat-section 177. As upper arm 171 is
moved to the right, roller 184 is removed from detent 185 and is
repositioned in detent 186. The foregoing motion of the actuator
arm is extremely rapid, so that the carrousel positioning platform
130 temporarily remains in a stationary position. At the completion
of the solenoid stroke, the actuator arm reaches the position shown
in phantom in FIG. 7. At this time, the solenoid is de-energized,
and the resiliency of the metallic bellows biases the actuator arm
toward its original position. The return of the actuator arm to its
original position is damped by the closing of flapper valve 178.
The flapper valve is provided with a hole therein so that the oil
can leak into the metallic bellows at a predetermined rate, thereby
providing a smooth, steady return motion to the actuator arm. As a
result, when the actuator arm is returned to its initial position,
detent 186 is moved to the position formerly occupied by detent
185, so that positioning platform 130 is advanced one position. As
the positioning platform is advanced, the cuvette compartments are
also advanced one position.
A stop lever 188 having a threaded adjustment screw 189 is used to
adjust the normal position of the actuator arm so that the
positioning platform will support the cuvette assembly in an exact,
predetermined position after every solenoid stroke. The cycling
assembly is used to sequentially advance the cuvette compartments
into the path of an analyzing beam.
Referring to FIG. 5, light is passed through the cuvette by
analyzing apparatus comprising a light source 402 having a filament
404 that produces light throughout the visible and ultraviolet
spectrum. The light source is held in a socket 401 by a spring 403
and an indexing plate 405. The light source supplies light to
lenses 406, 407 that focus the light through a mirror 408 onto a
ring-shaped filter 412 located on a disc 410, and to a commutator
ring of disc 410. Disc 410 rotates about an axis located in the
center thereof.
Disc 410 is rotated by a motor-gear unit 444 (FIG. 5) that rotates
a shaft 446 through a magnetic coupling 448 and bearings 450, 452.
Unit 444 is geared to rotate disc 410 at about 1800 rmp.
When filter 412 is being rotated, light from source 402 passes
therethrough and generates beams of light along a single path 454.
The monochromatic light pulses generated by the filter and source
402 in a single path pass through each specimen to be analyzed. For
example, if compartment 83 of cuvette 30 is located in the
analyzing position shown in FIG. 5, the pulses are passed through a
lens 456, reflected from a mirror 457, and transmitted through the
incubator bath chamber 124. The pulses thereafter pass through
planar portion 98 of cuvette 30, the specimen in compartment 83,
planar portion 100, bath chamber 124, a mirror 458, and another
lens 460 that focuses the resulting transmitted pulses onto a
portion of filter 412 that is 180.degree. displaced from the
portion of the filter which produced the pulses. Since
corresponding identical segments of the filter are displaced by
180.degree. of arc, each pulse is filtered by identical filters
before it enters the specimen and after it leaves the specimen.
After the pulses transmitted from the specimen pass through filter
412, they are transmitted into a photomultiplier transducer tube
462 that sequentially produces electrical pulse signals having
values proportional to the intensity of the light transmitted
through the specimen. Preferred apparatus for processing signals
produced by tube 462 is shown in the above-described related
application which is incorporated by reference.
Those skilled in the art will appreciate that the specific
embodiments described herein may be altered and changed by those
skilled in the art without departing from the true spirit and scope
of the invention which is defined in the appended claims.
* * * * *