U.S. patent number 3,622,795 [Application Number 04/766,488] was granted by the patent office on 1971-11-23 for colorimetric fluid test apparatus having plural fluid sequential control.
This patent grant is currently assigned to Coulter Electronics, Inc.. Invention is credited to Wallace H. Coulter, Ervin L. Dorman, Jr., Robert I. Klein, Robert L. Kreiselman.
United States Patent |
3,622,795 |
Dorman, Jr. , et
al. |
November 23, 1971 |
**Please see images for:
( Certificate of Correction ) ** |
COLORIMETRIC FLUID TEST APPARATUS HAVING PLURAL FLUID SEQUENTIAL
CONTROL
Abstract
Apparatus to be used in making hemoglobin determinations of
samples of blood and other colorimetric fluid tests, which includes
colorimetric computing circuitry and a flow-through cuvette in the
same housing, the flow-through cuvette being normally covered by a
lid which is raised by the operator when pouring the test sample
into the cuvette. The construction is such that the technician need
use only one hand for raising the lid and pouring the sample,
leaving the other hand free for making notes or other purpose. The
lid movement initiates programming means and the operating cycle,
which includes: draining a blanking fluid with which the cuvette is
filled between the cycles of use of the apparatus, accepting the
sample poured into the cuvette, making the colorimetric measurement
thereof, emptying the sample from the cuvette, rinsing the cuvette,
and refilling the cuvette with the blanking fluid for the next
measuring cycle. All fluid movement is achieved through the use of
a system operating in conjunction with suitable valves, solenoids
and at least one spring-return operated, piston-type liquid
dispenser. A novel cuvette construction provides concentric
fluid-receiving mouths leading to inner and outer receptacles, the
inner being the receptacle for the sample fluid, the outer being an
overflow basin. The receptacles lead to respective independent
drains, the inner being provided with a light transmitting section
at which the fluid is traversed by a beam of radiant energy.
Inventors: |
Dorman, Jr.; Ervin L. (Hialeah,
FL), Klein; Robert I. (Hialeah, FL), Kreiselman; Robert
L. (Miami, FL), Coulter; Wallace H. (Miami Springs,
FL) |
Assignee: |
Coulter Electronics, Inc.
(Hialeah, FL)
|
Family
ID: |
25076575 |
Appl.
No.: |
04/766,488 |
Filed: |
October 10, 1968 |
Current U.S.
Class: |
356/40; 250/432R;
356/42; 356/440; 137/624.13; 356/39; 356/246 |
Current CPC
Class: |
G01N
21/05 (20130101); G01N 21/85 (20130101); G01G
23/14 (20130101); G01G 3/08 (20130101); G01G
3/02 (20130101); Y10T 137/86405 (20150401) |
Current International
Class: |
G01N
21/03 (20060101); G01G 3/02 (20060101); G01N
21/85 (20060101); G01G 23/14 (20060101); G01N
21/05 (20060101); G01G 3/08 (20060101); G01G
3/00 (20060101); G01G 23/00 (20060101); G01n
021/26 (); E03b (); G01n 033/16 () |
Field of
Search: |
;137/624.11,624.12,624.13 ;250/218,43.5 ;356/246,39,40,41,42
;200/61.7 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lawrence; James W.
Assistant Examiner: Nelms; D. C.
Claims
What it is desired to secure by Letters Patent of the United States
is:
1. Colorimetric fluid test apparatus for rapidly and cyclically
comparing the absorbance of a reference fluid against a succession
of fluid test samples, comprising:
A. means providing a beam of radiant energy impinging on a
photoresponsive device,
B. a flow-through cuvette having a radiant energy transmitting
section in the path of the beam,
C. a source of an absorbance reference fluid and means directing
the flow of said fluid into said cuvette,
D. said cuvette also adapted to have one of a succession of fluid
samples poured into said cuvette from a vessel brought into pouring
position over said cuvette,
E. means for controlling the flow of the reference fluid into said
cuvette and both fluids out of said cuvette,
F. means responsive to signals from said photoresponsive device for
comparing against each other the absorbance of the reference and
sample fluids,
G. programming means for commanding the operation of said
flow-controlling means and said absorbance comparing means to occur
in a predetermined, rapidly repeating cycle of entry of the fluids
into said cuvette at mutually exclusive periods of time and
draining thereof from said cuvette, and
H. structure responsive to the bringing of said vessel into said
pouring position over said cuvette for initiating the operation of
said programming means.
2. Colorimetric fluid test apparatus comprising:
A. means providing a beam of radiant energy impinging on a
photoresponsive device,
B. a flow-through cuvette having a radiant energy transmitting
section in the path of the beam,
C. a source of a first fluid and means directing the flow of said
fluid into said cuvette,
D. said cuvette also adapted to have a second fluid poured into
said cuvette from a vessel brought into pouring position over said
cuvette,
E. means for controlling the flow of the first fluid into said
cuvette and both fluids out of said cuvette,
F. means responsive to signals from said photoresponsive device for
comparing the absorbance of the two fluids,
G. programming means for commanding the operation of said flow
controlling means and said absorbance comparing means to occur in a
predetermined cycle of entry of the fluids into said cuvette at
mutually exclusive periods of time and draining thereof from said
cuvette, and
H. structure responsive to the bringing of said vessel into said
pouring position over said cuvette for initiating the operation of
said programming means, in which said initiating structure
comprises a movable closure blocking the admission of said second
fluid into said cuvette and is required to be moved to unblocking
condition to enable said vessel to be placed in said pouring
position and in which said flow-directing means comprise a conduit
extending from said source of first fluid and having a discharge
end which moves into discharge position only when said closure is
in its blocking condition.
3. Apparatus as claimed in claim 2 in which said cuvette has two
separate receptacles arranged with upwardly opening concentric
mouths comprising an inner receptacle having said
radiant-energy-transmitting section and an outer overflow-receiving
receptacle, said flow directing means being arranged to flow said
first fluid into said inner receptacle and the second fluid adapted
to be poured into said inner receptacle, the said blocking position
of said closure being such as to cover both of said mouths.
4. The apparatus as claimed in claim 2 in which said initiating
structure also includes a control element operated by movement of
said closure.
5. The apparatus as claimed in claim 4 in which said control
element comprises an electrical switch having two circuit states
and being coupled with said closure member so that movement of the
closure member between blocking and unblocking conditions will
change the switch between said states, and in which said
programming means operation is electrically initiated when said
switch is in one of said states.
6. The apparatus as claimed in claim 4 in which said movable
closure is a lid hinged at one edge and adapted to be rotated
upward about said one edge, and in which said control element is a
switch linked to said lid for mechanical movement therewith.
7. The apparatus as claimed in claim 6 in which the switch is
electrical and the operation of said programming means is
electrically initiated by said switch when said lid is raised.
8. Colorimetric fluid test apparatus comprising:
A. means providing a beam of radiant energy impinging on a
photoresponsive device,
B. a flow-through cuvette having a radiant energy transmitting
section in the path of the beam,
C. a source of a first fluid and means directing the flow of said
fluid into said cuvette,
D. said cuvette also adapted to have a second fluid poured into
said cuvette from a vessel brought into pouring position over said
cuvette,
E. means for controlling the flow of the first fluid into said
cuvette and both fluids out of said cuvette,
F. means responsive to signals from said photoresponsive device for
comparing the absorbance of the two fluids,
G. programming means for commanding the operation of said
flow-controlling means and said absorbance comparing means to occur
in a predetermined cycle of entry of the fluids into said cuvette
at mutually exclusive periods of time and draining thereof from
said cuvette,
H. structure responsive to the bringing of said vessel into said
pouring position over said cuvette for initiating the operation of
said programming means, said structure also responsive to said
vessel being moved out of pouring position for further operation of
said programming means, and
I. said flow-directing means comprising a conduit extending from
said source of first fluid and having a discharge end which moves
into discharge position only when said structure is being
responsive to said vessel being moved out of pouring position.
9. The apparatus as claimed in claim 8 in which said cycle includes
two phases, one phase being initiated when said vessel is brought
into said pouring position and the other phase being initiated when
said vessel is moved out of said pouring position.
10. The apparatus as claimed in claim 9 in which said initiating
structure comprises a movable closure blocking the admission of
said second fluid into said cuvette and is required to be moved to
unblocking condition to enable said vessel to be placed in pouring
position, said closure being constructed such that it will return
to blocking condition when said vessel is moved out of pouring
position.
11. The apparatus as claimed in claim 10 in which said initiating
structure also includes a control element operable between two
control conditions by movement of said closure between blocking and
unblocking conditions.
12. The apparatus as claimed in claim 11 in which the first phase
of said cycle comprises draining first fluid remaining in said
cuvette from a previous cycle and accepting and retaining said
second fluid poured into said cuvette, said programming means
commanding performance of said first phase when said control
element is in one control condition, the second phase of said cycle
comprising responding to the absorbance of said second fluid and
making said comparison, draining the second fluid from said cuvette
and replacing the same with a quantity of first fluid and
responding to the absorbance of said first fluid while retaining
same in said cuvette, said programming means commanding performance
of said second phase when said control element is in said second
control condition.
13. The apparatus as claimed in claim 12 in which said second phase
further includes a filling of said cuvette with said first fluid
and a draining thereof without measurement, for rinse purposes
after the draining of said first fluid from said cuvette.
14. Apparatus as claimed in claim 8 which said flow-directing means
further comprise a piston-type liquid dispenser connected to said
conduit upstream of said discharge end.
15. Apparatus as claimed in claim 12 in which said cuvette has two
separate receptacles arranged with upwardly opening concentric
mouths comprising an inner receptacle having said
radiant-energy-transmitting section and an outer overflow-receiving
receptacle, said flow-directing means being arranged to flow said
first fluid into said inner receptacle and the second fluid adapted
to be poured into said inner receptacle, said lid covering both of
said mouths when in blocking condition, said second phase also
including draining any fluids from said overflow receptacle.
16. Apparatus as claimed in claim 8 in which said cuvette has two
separate receptacles arranged with upwardly opening concentric
mouths comprising an inner receptacle having said
radiant-energy-transmitting section and an outer overflow-receiving
receptacle, said flow directing means being arranged to flow said
first fluid into said inner receptacle and the second fluid adapted
to be poured into said inner receptacle.
17. Apparatus as claimed in claim 15 in which said flow-directing
means comprise a first piston-type liquid dispenser having a
discharge end coupled to discharge said first fluid into said inner
receptacle.
18. Apparatus as claimed in claim 17 in which the receptacles have
independent drain means operated by said flow-controlling means
which further comprise a second and a third piston-type liquid
dispenser, respectively connected to said independent drain
means.
19. Colorimetric fluid test apparatus for rapidly and cyclically
comparing the absorbance of a reference fluid against a plurality
of different fluid test samples comprising:
A. means providing a beam of radiant energy impinging on a
photoresponsive device,
B. a flow-through cuvette with an upwardly opening mouth, having a
radiant energy transmitting section in the path of the beam,
C. a source of a first fluid, such fluid to be employed cyclically
as the absorbance reference, and means directing the flow of said
reference fluid into said cuvette, said flow-directing means
including a fluid-conducting path from said source to said cuvette
and a first piston-type liquid dispenser within said
fluid-conducting path between said cuvette and source,
D. said cuvette also adapted to have a second fluid poured into the
mouth of said cuvette from an external vessel, said second fluid
constituting a test sample,
E. means for controlling the flow of the reference fluid into said
cuvette and both fluids out of said cuvette, said flow-controlling
means including automatic means operating the piston of said
dispenser to withdraw a measured quantity of reference fluid out of
said source on one movement of the piston and to dispense said
amount into said cuvette on an opposite dispensing movement of said
piston,
F. means responsive to signals from said photoresponsive device for
comparing against each other the absorbance of the two fluids,
and
G. programming means for commanding the operation of said
flow-controlling means and said absorbance comparing means to occur
in a predetermined cycle of entry of the fluids into said cuvette
at mutually exclusive periods of time and draining thereof from
said cuvette and providing rapidly repeating cycles for entry of
different of the test samples.
20. The apparatus as claimed in claim 19 in which said piston has
spring-biasing means for producing said dispensing movement, said
piston operating means comprise a source of vacuum and a vacuum
line extending to said dispenser and connected to reduce pressure
on one face of the piston, said flow-controlling means include a
first valve in said line, and said programming means controls
operation of said first valve to relieve the vacuum to permit said
spring-biasing means to drive the piston in dispensing movement
during said cycle.
21. The apparatus as claimed in claim 20 in which said cuvette has
a drain and said source of vacuum has a second line connected to
said drain, said flow-controlling means includes a second valve in
said second line, and said programming means controls said second
valve to enable draining said cuvette of first or second fluid
during said cycle.
22. The apparatus as claimed in claim 21 in which a two-state
control element is provided for operating said programming means in
two phases of said cycle, the normal condition of said apparatus
with the control element in one state being with the valves closed,
a quantity of first fluid in the dispenser and in the cuvette, the
response to the absorbance of said first fluid having been received
and stored in said comparing means, the first phase beginning with
a change of the state of the control element to its second state
and a pouring of said second fluid into said cuvette thereafter,
and said first phase consisting of opening the second valve to
drain the first fluid from said cuvette and closing the same valve
in quick succession to enable the cuvette to retain said second
fluid, the second phase beginning with a reversion of the control
element back to its first state, and comprising responding to the
absorbance of the second fluid and comparing said response with
that of the first fluid to obtain the difference, opening the
second valve to drain the second fluid from said cuvette, closing
said second valve, opening the first valve and dispensing said
measured quantity of first fluid into said cuvette and closing said
first valve to draw another quantity of first fluid into said
dispenser and responding to and storing the absorbance of said
measured quantity in the cuvette.
23. The apparatus as claimed in claim 22 in which the second phase
includes opening and closing of said second valve and a subsequent
opening and closing of the first valve so that the first quantity
of first fluid dispensed into said cuvette comprises a rinse.
24. The apparatus as claimed in claim 19 in which said
flow-controlling means comprise at least a second piston-type
liquid dispenser connected to said cuvette and coupled to said
programming means for purposes of draining said cuvette.
25. The apparatus as claimed in claim 24 in which a two-state
control element is provided for initiating operation of said
programming means, said cuvette having said measured quantity of
first fluid therein while said control element is in one state, the
first fluid being drained from said cuvette and the cuvette
conditioned to receive the second fluid when the control element is
placed in the second state, an absorbance response to said second
fluid being received by said comparing means after said control
element has been returned to its first state, said cycle including
the sequential draining of said second fluid from said cuvette,
further dispensing of first fluid into said cuvette, and an
absorbance response to said first fluid being received and stored
by said comparing means.
26. Apparatus as claimed in claim 25 in which said cuvette has two
separate receptacles both arranged with upwardly opening concentric
mouths comprising an inner receptacle, having said
radiant-energy-transmitting section, and an outer
overflow-receiving receptacle, said directing means being arranged
to flow said first fluid into said inner receptacle, and the second
fluid to be poured into said inner receptacle.
27. Apparatus as claimed in claim 26 in which said second
piston-type liquid dispenser has an input connected to said inner
receptacle, for draining same and said flow-controlling means
further comprise a third piston-type liquid dispenser having an
input connected to said outer receptacle, for draining same.
28. Apparatus as claimed in claim 27 in which solenoid drive means
is provided for each of said liquid dispensers and check valves are
positioned at the input and output of each liquid dispenser.
Description
REFERENCE TO RELATED APPLICATIONS
In the specification and claims herein reference is made to a
measuring circuit which gives a signal output representing the
colorimetric comparison between a sample liquid and a reference
liquid. The particular purpose for which the apparatus was intended
is to measure the hemoglobin content of a blood sample, although
this in not intended to be limiting of the invention. The
electronic circuit receives a signal from the optical portion of
the device which represents the light absorbance of a reference
liquid, remembers this signal, then receives a second signal which
represents the light absorbance of the sample, then compares the
two signals and provides an output signal that is proportional to
the absorbance of the sample, related in terms of the number of
grams of hemoglobin per 100 cubic centimeters of blood.
Apparatus which provide the circuitry and structure for
accomplishing this kind of measurement are disclosed and claimed in
the following application:
Ervin L. Dorman, Jr. and Walter R. Hogg application, Ser. No.
713,958 filed Mar. 18, 1968, U.S. Pat. No. 3,566,133 and entitled A
HEMOGLOBINOMETER.
Although it is intended that the apparatus of the invention herein
use the circuitry of the copending application mentioned above, any
other circuitry may be used which is capable of measuring the
absorbance of a sample of liquid as related to the absorbance of a
reference liquid.
The instant application, as well as the copending application, are
owned by a common assignee. The applicant Ervin L. Dorman, Jr.,
named in said copending application is the same applicant named
with others herein.
FIELD OF THE INVENTION
The invention relates generally to measurement of absorbance of
light in a liquid, and more particularly relates to the absorbance
of light of a particular wavelength in a specific liquid in order
to ascertain the colorimetric factor which caused the absorbance.
The most important example, as considered by the principal purpose
for the invention, is the ascertaining of the hemoglobin content of
a sample of blood. This index is well known in medicine, and
furnishes important information for diagnosis and cure of disease.
Through the use of the information relating to hemoglobin, other
indices of the blood may be obtained which provide additional
important data.
Sufficient discussion of the nature of hemoglobin are contained in
the copending applications to justify curtailing detailed
discussion herein. Suffice it to say that a blood sample is
diluted, treated to release the protein pigment of the red cells,
and this latter mixed with a suitable reagent to provide the
necessary sample liquid. Light of a particular wavelength is passed
through the liquid and its absorbance represents the change in
color caused by the presence of the pigment. This absorbance is
compared with the absorbance of the same beam of light passing
through a reference, which ideally is of the identical color as the
diluent. The difference is the absorbance due only to the pigment,
and this is related to the hemoglobin content of the original blood
sample.
The invention contemplates a fully automatic device in which the
operator performs only one simple act and causes the entire process
of measurement to take place. This act consists of pouring a liquid
sample into the cuvette of the apparatus from a vessel. Actually,
the act is made up of several simple motions which may be described
as follows: first, the technician brings his hand holding the
liquid sample close to the device; next, with the same hand he
lifts the lid covering the cuvette and holding the lid in open
position, he pours the sample liquid into the center receptacle of
the cuvette; finally, he removes his hand carrying the vessel away
from the device and permits the lid to drop down to its original
closed position. The hemoglobin index immediately appears as a
readout from the device and the apparatus is ready for the next
sample.
In the structure described above the lid carries a switch which is
actuated to one condition when the lid is opened and is actuated to
another condition when the lid is closed. These conditions activate
the programming device and cause the functions of the apparatus to
be performed. A simple mercury switch or any other can be used,
being normally open when the lid is closed and closed when the lid
is open--or vice versa, if desired.
The invention contemplates that the act of bringing the
technician's hand adjacent the apparatus can be used in several
alternate schemes to perform the same functions. For example, it
could interrupt a light beam, or change the capacitance of a tank
circuit, ro actuate a heat-sensitive switch of the type used in
modern elevators. Removal of the hand would restore the controlled
switching circuit to its original condition. This, of course, would
eliminate the need for a lid or cover member over the cuvette, but
as will be seen, this lid provides advantages which justify its use
as being preferred.
Any colorimetric measurement may be made by the device, and not
necessarily a determination of hemoglobin. This should be kept in
mind during a reading of the specification and a consideration of
the claims.
DESCRIPTION OF THE PRIOR ART
The literature on methods and apparatus for measuring hemoglobin is
quite extensive. The most common methods used in laboratories today
are batch methods, although some flow-through apparatuses are
available albeit they are expensive. Spectrophotometers are in
general use, using split beams to compensate for changes in the
system during the measurement of samples. These provide the
monochromatic light required by international standards, or the
light can be provided by filters. The invention herein contemplates
a simple system not requiring expensive apparatus, and it is
substantially compact.
Some of the prior art contemplates chemical methods, but the method
utilized by the invention is colorimetric and has been described as
comparing the color of the acid hematin of a diluted blood sample
with a standard and calculating the hemoglobin content of the
original blood sample from the result of colorimetric evaluation.
This descriptive statement will be noted in a discussion in U.S.
Pat. No. 3,374,063, which itself is concerned with a chemical
method.
SUMMARY OF THE INVENTION
The invention contemplates a compact apparatus in one or at most
two housings, light in weight and easily transported. The
technician has nothing to do, after the hemoglobin sample has been
prepared, but to pour it into the apparatus. The hemoglobin index
appears almost immediately as a readout. The next sample requires
nothing more than the same act.
In order to accomplish the above, the apparatus of the invention
provides for a sequence of events that make the same reliable, fast
and accurate.
The apparatus has a cuvette which is connected with a liquid system
operated by suitable valves, these valves are actuated as a result
of the proximity of the technician's hand with the sample vessel
held therein. In the preferred embodiment, the cuvette mouth is
covered by a hinged lid, and the technician lifts the lid using the
knuckles of the same hand that holds the sample vessel. This closes
an electric switch in a programming circuit. After the liquid is
poured into the cuvette, the hand is taken away, the lid lowered,
and the same switch is opened. The programming circuit operates the
measuring device to provide the desired information, and this is
used to drive some kind of readout device, such as digital display
electronic counter tubes.
When the lid has been lowered, the photoresponsive circuit is
programmed to provide a signal representing the absorbance of a
beam of specific wavelength of radiant energy which has passed
through the center receptacle of the cuvette carrying the sample,
and since the measuring circuit has been remembering a signal from
a reference liquid which previously had been in the receptacle, it
can make the comparison and computation. As soon as this is done,
by a system of valves and the use of a liquid dispenser, the
cuvette is emptied of the measured sample, rinsed with diluent,
emptied, filled with diluent, and a measurement is made of
absorbance of the diluent and is electrically stored in the
measuring circuit, waiting for the next sample measurement.
The actual function performed when the lid is lifted is to close a
circuit which starts the programming cycle. The first thing that
happens is to empty the reference, comprising a quantity of diluent
standing in the center receptacle of the cuvette. The liquid line
leading from the center receptacle is then quickly closed so that
the next sample may be poured in and will not drain out.
The programming means also programs the draining of liquid from an
overflow receptacle, which is coaxially arranged as an annular
basin around the principal receptacle.
The cuvette construction, and the arrangement for mounting the
cuvette and its associated apparatus are believed also novel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a system constructed in accordance
with the invention, same being primarily a flow diagram, but also
including some electrical circuitry and blocks representing the
measuring circuit, programming means and readout device, these
three elements being capable of assuming many different forms.
FIG. 2 is a bar chart illustrating the operation of the apparatus
on the basis of time sequence energization of the several solenoids
illustrated in the diagram of FIG. 1.
FIG. 3 is a perspective view illustrating the apparatus of the
invention in use.
FIG. 4 is a fragmentary median sectional view taken generally on a
vertical plane at the line 4--4 of FIG. 3 and in the indicated
direction, showing the optical system of the apparatus located at
the front thereof.
FIG. 5 is a perspective view of the cuvette of the apparatus
dissociated from the remainder of the apparatus.
FIG. 6 is a median sectional view through the cuvette generally
along a vertical plane at 6--6 of FIG. 5 and in the indicated
direction.
FIG. 7 is a sectional view taken through the cuvette generally
along the line 7--7 of FIG. 6 and in the indicated direction.
FIG. 8 is an exploded perspective view of the components making up
the mounting means for the optical system of the apparatus.
FIG. 9 is a partial schematic diagram of the system, illustrating
an alternate embodiment of the fluid flow control elements.
FIG. 10 is a bar chart showing the sequencing of that portion of
the embodiment of FIG. 9 which differs from the timing sequence in
FIG. 2
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention will best be understood preliminarily by considering
the flow diagram of FIG. 1 in conjunction with the timing sequence
chart of FIG. 2. The several symbols used in the chart of FIG. 1
are for the most part conventional, although the system is believed
novel. Likewise, some of the components illustrated are believed
novel, these including the flow-through cuvette and the measuring
circuit, the latter being disclosed and claimed in said copending
application Ser. No. 713,958. Other measuring circuits can be
used.
Referring to the flow diagram, the fluids which are utilized for
achieving the operation of the apparatus comprise gas and liquid,
the gas in this case being air, and the liquid being diluent and
the blood sample. A reservoir of diluent is shown at 20, this
diluent being that which has been used previously to dilute the
blood sample. This same diluent is used to rinse the cuvette and
likewise serves as a blank or standard for use in comparing with
the colorimetric response of the blood sample. Most diluents will
have some color, and it is best that the so-called blank take this
color into account. The liquid conduit 22 is connected to the
reservoir 20 and extends through a check valve CV2 to a liquid
dispenser pump 24, with a lateral connecting line 26 branching down
between the valve CV2 and the pump 24.
The pump 24 includes a cylinder 28 which has a free piston 30
therein, there being helical spring 32 on the left side of the
piston 30 whose function is to dispense the fluid when permitted to
do so. The left-hand end of the cylinder 28 is connected to the
atmosphere by way of the air conduit 34 in which the normally
closed valve V1B is located. The air conduit 34 is a branch of the
principal air line 36 which connects directly with the left-hand
end of the cylinder 28. The air line 36 has a normally open valve
V1A in the path of airflow, followed by a vacuum reservoir 38 which
may be in series, if desired, and a check valve CV1. At the bottom
of the air line 36, connection is made at 40 with the liquid flow
line 42 that brings fluids from the cuvette 50, and the combined
liquid and air line 44 connects with a vacuum pump 46 by means of
which air and liquid are constantly being sucked out of the lines
if the valves and connections are suitably arranged therefor.
The flow-through cuvette 50 has inner and outer receptacle parts 52
and 54, respectively, the principal receptacle being the inner one.
The exact construction will be described in detail in connection
with FIGS. 5, 6 and 7 hereinafter. The inner or central receptacle
52 is substantially longer than the outer one, the latter serving
as the overflow receptacle. The word "cuvette" will be used
principally to refer to the entire structure comprising both
receptacles. The central receptacle has a central
light-transmitting section at 56 through which a beam of radiant
energy is to be projected, as described below, for the purposes
described in said copending applications. Also, there is a drain
formed at 58 at the bottom end of the receptacle 52. The outer or
overflow receptacle 54 is relatively shallow and has a drain 60
formed at the bottom end thereof, neither the receptacle nor its
drain being located to interfere with clear passage of the radiant
energy beam through the light-transmitting section 56 of the
central receptacle.
When permitted to do so, liquid dispensed through the line 26 will
pass through the valve V1C and will enter the upwardly opening
mouth of the central receptacle 52 of the cuvette 50 by way of the
nozzle 62. Also, as described later, the operator may pour a sample
into the central receptacle by way of its mouth. Overflow from
either of these operations will enter the annular mouth of the
overflow receptacle 54 and pass to the bottom thereof at the drain
60. In both cases, the liquid will flow down into the respective
conduits 64 and 66, being blocked normally by the normally closed
valves V2 and V3. If permitted to pass through these valves, the
liquid will enter the liquid flow line 42 by way of the respective
branches 68 and 70. It should be kept in mind that the valves V2
and V3 need not operate simultaneously.
The block 72 represents a programming device, which in a practical
example is preferably an electronic logic circuit providing
necessary signals to accomplish the desired sequence of events
operating the system. It could alternatively be a timed rotating
member with suitable contacts to be made and broken in desired
sequence, as used in some well-known types of apparatus. The
precise structure is not material to the invention. The programming
device operates three solenoids S1, S2 and S3 through the
connections 74, 76 and 78, respectively. It also energizes the
measuring circuit 79 at the proper time with respect to the
sequence of events, the connection 80 being indicative of this
control. The lines or connections respectively may be electrical
leads or a plurality thereof, the diagram being symbolic and not
intended to constitute an actual electrical circuit.
The solenoids in the diagram FIG. 1 are connected to the several
valves by dashed lines, these signifying mechanical driving
connections. Thus, the solenoid S1 is connected to the valves V1A,
V1B and V1C by the respective dashed lines 82, 84 and 86 because
all three of these valves are mechanically operated simultaneously
when the solenoid S1 is energized. The condition of the respective
valves is indicated alongside the valves in FIG. 1, so that V1A is
normally open, V1B is normally closed and VIC is normally closed.
When the solenoid S1 is energized, the valves operate to the
conditions closed, open and open, respectively. When the solenoid
is deenergized, these valves return to their normal condition.
Solenoid S2 is connected to the outer receptacle drain valve V2
which is normally closed by the mechanical driving connection 88.
The solenoid S3 is connected to the central receptacle drain valve
V3 by the mechanical driving connection 90.
The programming means 72 is initially started by the closing of a
switch SW1 that is connected to the lid 92 of the apparatus, as
will be described. Switch SW1 has an electrical connection 94 with
the programming means 72.
Starting with the condition that the lid 92 is down, covering the
mouths of the receptacles of the cuvette 50, at this time, the
condition of the respective valves is as indicated alongside the
valves in FIG. 1. The receptacle 52 is filled with liquid
comprising the same diluent which was used to make the blood sample
to be measured, this liquid being that shown at 96 in the reservoir
20. None of the solenoids has been energized. This condition is
represented on the bar chart as the period of time before
t.sub..sub.- and the period of time after 3.75 seconds, this latter
being the end of the cycle. The entire apparatus has been
energized, of course, and the vacuum pump 46 is operating, pulling
a vacuum in the lines 42 and 36. This has pulled the piston 30 to
the left against the bias of the spring 32, which is now contracted
and has potential energy stored in it. When the piston moves to the
left, diluent 96 is drawn through the check valve CV2 into the
cylinder 28 on the right-hand side of the piston 30. It therefore
fills the line 22 throughout its extent and likewise the chamber in
the cylinder to the right of the piston 30. The line 26 will always
be filled. At this time, the center receptacle 52 is filled with a
charge of liquid consisting of the diluent 96. It has been
deposited there as a part of the previous cycle. The optical system
is "looking" at this liquid, which is the reference fluid. The
blood samples, which are to be tested for hemoglobin content in the
apparatus, have been diluted using this identical fluid, so that
whatever the response of the optical system due only to the cast of
the diluent, this color will be compensated by reason of using the
diluent as a reference. Obviously, this is not essential, since the
apparatus may be calibrated using any other kind of liquid, clear
or colored.
The optical system will be described in detail below, but for the
moment, there is a light source 100 which projects a beam of light
104 through a suitable color filter 102 in order to achieve the
desired wavelength of light required for a hemoglobin
determination. The wavelength according to the international
standard of today is 540 nanometers, and this may be achieved by
color filters. The formula which is accepted as the definition of
hemoglobin in grams per centimeter as given in said copending
application Ser. No. 713,958, is based upon absorbance in the
sample while traversing 1 centimeter of length, and the length of
the path of the beam 104 through the liquid blood sample in the
light-transmitting section 56 is considered in the measurement and
computation of the index. There is a photoresponsive device 106
which has the beam 104 projected thereon after it has passed
through the section 56. Although the diagram of FIG. 1 appears to
have the drain 60 in the path of the beam 104, the drain is
actually displaced from the beam by a substantial angular distance
and does not interfere therewith.
The circuits for the optical system are connected to the measuring
circuit 79, such as shown in FIG. 1. The photoresponsive device 106
is connected by the channel 108 to the measuring circuit 79 so that
the response produced therein may be used to make the necessary
computations and achieve the desired information. The light source
100 is energized by the connection 110 from any suitable electrical
energy source, and is shown in FIG. 1 connected to the measuring
circuit 79 although this is not essential, since the light source
100 may be energized at all times. Some form of good regulation is
preferred for the electrical energizing of the light source. As
will be seen, the measuring circuit 79, programming means 72 and
the readout device 112 are all conveniently housed in a single
cabinet or housing.
With the beam 104 passing through the reference liquid and
impinging upon the active element of the photoresponsive device
106, the resulting output of the device is a signal which
establishes a condition in the measuring circuit of the type
described in said copending application. The apparatus is now ready
for the next signal.
Looking now at FIG. 2, the next period of time commences at
t.sub..sub.-2 with the raising of the lid 92 by the technician. As
seen in FIG. 3, this is easily done by the technician grasping the
test tube or other vessel 114 in his hand 116, raising the lid 92
with his knuckles or fingers, and holding the lid while he pours
the sample 118 into the cuvette 50. This could be as easily done
with the left hand as the right. As soon as the lid is raised, a
mercury switch SW1 connected to the lid 92 by the bracket 119
closes and the programming device 72 energized the solenoid S3. The
bar 120 extending from time t.sub..sub.-2 to t.sub..sub.-1
represents the energization of the solenoid S3 for a period of
three-fourths of a second, which, of course, is substantially less
than the time that it takes for the technician to lift the lid
fully and bring the mouth of the vessel 114 into position for
pouring. During this period of time, the conditions of the other
two solenoid S2 and S1 do not change, and the bars 122 and 124 are
still shown in the "OFF" level in the bar chart FIG. 2.
As soon as the solenoid S3 is energized, it opens the valve V3 and
keeps it open for the three-fourths second mentioned above, during
which time the vacuum pump 46 sucks the diluent from the receptacle
52 by way of the lines 70, 42 and 44 and discharges the same to
waste. When the solenoid S3 once more reverts to its original off
condition, the valve V3 closes, as indicated by the bar 126 and
remains closed from the time t.sub..sub.-1 until one-fourth second
after the time "0" on the bar chart. This period of time is
indefinite because it represents the time that the technician uses
to empty the contents of the vessel 114 into the center receptacle
52 of the cuvette 50 and to permit the lid 92 to lower to its
covering position. Experience has shown that this will probably be
of the order of 2 or more seconds.
While the sample 118 is being poured into the center receptacle,
the conditions of the respective solenoids are the same as during
those periods between cycles, except that the receptacle 52 has
been emptied of the reference liquid.
When the lid 92 has been lowered sufficiently to open the switch
SW1, the timing represented by the bars to the right of 0 in FIG. 2
commences. The programming means 72 responds to the closing of the
switch SW1 first, by commanding the measuring circuit 79 to make
the measurement needed to obtain the value of the absorbance of the
sample which was poured into the receptacle 52. The same light
source 100 and photoresponsive element 106 are used to produce the
signal. This measurement occurs some time between 0 time and
one-fourth second later, preferably toward the end of this period
of time. As soon as the measurement is made, the circuit described
in the copending application, preferably that of application Ser.
No. 713,958, makes the computation and the index appears in the
readout device 112 as a number seen by the technician. Note the
window 128 of the housing 150 of FIG. 3 in which there are shown
the axial ends of three digital display counter tubes 130 which
provide the visual display desired. The technician can see this
index almost immediately after pouring the sample into the cuvette
50.
At the point in time designated 0.25 second, the programming means
again energizes the solenoid S3 and the condition thereof is
represented thereafter by the bar 132. Thus, the sample which was
disposed in the receptacle 52 empties to waste in the manner
described in connection with the previous energization of the
solenoid S3.
At the time designated 1 second, the solenoid S3 is once more
deenergized and this is represented by the bar 134. This means, of
course, that the valve V3 is closed for three-fourths second after
the 1-second point. During the same period, the programming means
energizes the solenoid S1 which operates the three valves V1A, V1B
and V1C. The valve V1A closes, blocking the vacuum effect from
being felt in the line 36. The valve V1B opens to atmosphere,
relieving any vacuum remaining in the line 36, and the spring 32 is
now permitted to expand from its previously contracted condition.
Since the valve V1C is also opened, the spring 32 pushes the piston
30 to the right, emptying the contents of the right-hand end of the
cylinder 28 into the line 22 from which it passes by way of the
lateral branch 26 through the nozzle 62 into the receptacle 52. The
bar representing this action is 136, its length being three-fourths
second. The cuvette is filled with diluent for this period of time,
the programming device acting to provide the necessary commands.
The optical system is also rendered inoperative by the programming
device, since the purpose of the introduction of the liquid into
the receptacle 52 at this time is for rinsing.
The next period of time extends from 1.75 seconds to 2.5 seconds,
also a period of three-fourths second. During this period as seen
from the bar chart, the solenoid S1 is deenergized as indicated by
the bar 138 and the solenoid S3 is energized as indicated by the
bar 140 and the result will be that the liquid in the receptacle 52
will be drained to waste. At 2.5 seconds, the solenoid S3 is
deenergized, the solenoid S1 energized and, for the first time, the
solenoid S2 is energized.
The bars 142 and 144 provide the same conditions that existed
between 1 second and 1.75 seconds, so, the cuvette 50 is once more
filled with diluent, but since the solenoid S3 is not energized
after the liquid dispenser pump 24 has operated, the charge of
liquid remains in the receptacle 52. Note that the condition of
solenoid S3 obtains to the end of the cycle and continues as bar
144 until the time t.sub..sub.-2 of the next succeeding cycle. The
condition of the solenoid S1 reverts to deenergized after
three-fourths second as indicated by the bar 124, and this likewise
obtains until the start of the next succeeding cycle. The
energizing of the solenoid S2 from the time 2.5 seconds to the time
3.75 seconds as indicated by the bar 148 causes the mechanical
connection 88 to open the valve V2 and this enables the vacuum pump
46 to suck any overflow liquid from the receptacle 54 out of the
drain 60 by way of the lines 64, 68 and 42 to the main line 44 and
discharge the same to waste. Thereafter the solenoid S2 is
deenergized and reverts to its original condition represented by
the bar 122.
The filling and draining of the cuvette 50 as represented by the
sequence from 1 second to 2.5 seconds may be programmed to repeat
several times if desired, since this is a rinsing function. In this
described structure, the rinsing is done only once, after which the
receptacle 52 is permitted to retain the diluent. If the rinsing is
not needed for some types of colorimetric measurements, the fill
and drain cycle may be omitted, and the receptacle 52 is filled
with the reference sample immediately after the test sample has
been drained.
The structure described above uses very little sample and diluent.
The charge provided by the dispenser 24 need only be about 3 cc.
The overflow assures that no liquid will contaminate the optical
system and likewise assures that the receptacle 52 will be full, or
at least have sufficient liquid to fill the measuring section 56.
The technician will not hesitate to pour as much liquid as required
into the cuvette because he knows that the overflow receptacle 54
will be emptied once each cycle when the solenoid S2 is energized.
Its volume could be chosen at about 5 to 7 cc., while the volume of
the center receptacle 52 is about 21/2 to 3 cc. The maximum vacuum
is used for draining the center receptacle 52 by draining the
overflow receptacle 54 while valve V3 is closed and not during any
period of time that speed of draining receptacle 52 is
important.
The reservoir 38 provides a constant vacuum notwithstanding the
pulsing of the pump 46, so that the action of the piston 30 will be
fast and so that it will stay in "cocked" position during the
portion of the cycle that it is compressing the spring 32. In FIG.
3 the apparatus of the invention is illustrated in a design which
is convenient. The cabinet 150 will house the entire electrical
circuitry, including the programming means 72, the measuring
circuit 79 and the readout 112. In the view there has been shown
another cabinet or housing 154 which conveniently will carry the
vacuum pump 46, an electric motor (not shown) to drive the pump,
the vacuum reservoir 38 and various other parts of the apparatus,
but these could easily be incorporated into a single cabinet. The
separation of the electrical parts from these larger components of
the liquid system may make for ease of assembly and servicing. Some
of the valves and the pump 24 are easily included in the main
cabinet 150.
The optical system and the cuvette mounting means are supported in
a chassis of sheet metal such as indicated at 158 that is connected
to the front of the cabinet 150 as shown at 160 in FIG. 4. The
mounting gives easy access to these structures especially if an
outer shroud or sheet metal enclosure 162 is provided to be removed
readily. Slots and thumbscrews as at 164 provide for removability
of the shroud 162.
The cabinet 150 has cables and connections with the cabinet 154,
these including fluid and electrical connection and being indicated
at 166. The main electric power cable from the power line is shown
at 168. Only one operating control is needed, being the main power
switch 169.
The lid 92 is hinged at 170 to the front wall 172 of the cabinet
150 and preferably has an overhang 174 extending forward of the
shroud 162 and over its sidewalls so that the technician may easily
be enabled to engage his hand under the lid to lift the same when
using the apparatus. There is a fitting 176 secured to the
underside of the lid aligned with the center of the receptacle 52
so that the nozzle 62 may be supported thereat. The nozzle is part
of the flexible pipe 178 that connects through the wall 172 with
the valve V1C that is not shown in FIG. 4.
Looking now at FIGS. 4 and 8, the center of the chassis 158 mounts
three blocks 180, 182 and 184 which are secured together by any
suitable fastening means to from the assembly shown in FIG. 8. The
mounting block 180 carries the cuvette 50, and is provided with a
shallow recess 186 for seating the fillets or bulges formed in the
cuvette at the points where the depending portions are connected,
and two vertical passageways 188 and 190 for accommodating the
drain 60 and the measuring section 56 of the cuvette 50. When
engaged in these passageways, the bowllike exterior of the
receptacle 54 will be spaced slightly above the upper surface of
the block 180. A cylindrical passageway passes horizontally through
the block, intersecting the vertical passageway 190 and another
vertical passageway 194, and opens to the bottom of a groove 196 at
198. The groove 196 accommodates a glass or other filter, and since
the groove opens to the side of the assembly, the filter 102 is
readily exchanged for any suitable other kind. The passageway 192
is aligned with the light-transmitting section 56 when the
structure is assembled so that the beam of light 104 passing
coaxially through the passageway 192 will also pass through any
liquid in the section 56.
The block 182 has a vertical cylindrical bore 200 which aligns with
the vertical passageway 194 when the block 182 is connected to the
bottom of the block 180. A photoresponsive device 106, such as a
photomultiplier tube is mounted in the block 182 with its sensitive
element 202 facing the opening 198 and aligned therewith. A
suitable setscrew 204 holds the base 206 of the tube 106 in place.
Over the front of the block 180, there is secured the lamp-mounting
block 184, having a central horizontal passageway 208 aligned with
the passageway 192. A lamp 100 is mounted to a socket 210 that
plugs into the end of the passageway 208 so that the lamp may serve
to provide a light source. The lamp 100 is preferably of a type
having a lens 212 incorporated in the end thereof to enable
collimating of the light.
Light passes through the filter 102 and the liquid in the
light-transmitting section 56 and illuminates the element 202 of
the tube 106. The purpose is as explained above.
Reference may now be had to FIGS. 5, 6 and 7 for the details of the
cuvette 50. The cuvette is preferably formed from glass parts
suitable fused together by well-known glassblowing techniques. The
receptacle 52 and the receptacle 54 are concentric with the
receptacle 52 having a bell-shaped mouth 220 opening in the center
and slightly below the annular flanged rim 224 of the receptacle
54. This rim 224 engages upon the top of a resilient pad 226 (see
FIG. 4) which supports the same. The receptacle 45 is in the form
of an annular bowl that slopes slightly toward the lateral opening
228 which serves as the entrance to the depending drain 60. The
light-transmitting section 56 is somewhat oval at the point where
the beam 104 passes through the same and the opposite walls are
flat at this point to prevent distortion and refraction of the beam
and to enable the distance between them to be easily
ascertained.
Modifications of the structure are capable of being made within the
scope of the invention. For example, a cuvette could be used
without the overflow receptacle 54 and the added drain and
electrical and fluid structure for emptying the same. Certain
advantages would be lost, but benefits as taught by the invention
would be achieved. The method of initiating the operation of the
programming means is preferred to be a lid, covering the mouths of
the cuvette, but instead there could be some other structure which
is actuated when the technician's hand comes into sample-pouring
position. The lid is preferred because it prevents contamination of
the sample and the reference, and keeps light out of the optical
system. Other modifications can be made.
As understood from the above, although the apparatus is
specifically intended for use as a hemoglobinometer, it is capable
of making colorimetric determinations of fluid other than blood
samples. The filter 102 is readily changed to give wavelengths as
desired, and modifications readily made in the measuring circuit 79
to provide the desired range of measurements.
One modification, which would increase the compactness of the
apparatus and enable all components to be contained in a single,
relatively small housing, is shown in FIG. 9. Such modification
relates to the fluid controlling elements, and, except as next
specifically noted, is the same as that described in connection
with FIGS. 1 and 2.
The primary purpose of this modification is to eliminate the bulk
of the vacuum reservoir 38, the vacuum pump 46, and the need for
solenoid driven valves, while retaining the simple fluid flow
pattern and programmed cyclic action of the primary embodiment.
Such is accomplished by employing the solenoid S1 to actuate the
fluid dispensing pump 24, and by adding similarly operating fluid
pumps 230 and 232 actuated respectively by the solenoids S2 and
S3.
All of the solenoid driven valves are eliminated as well as the
check valve CV1. In lieu thereof there are a check valve CV3 in the
line 26 leading to the nozzle 62; check valves CV4 and CV5 leading
to and from the fluid pump 232, respectively in the conduit 66 and
branch 70; and check valves CV6 and CV7 leading to and from the
fluid pump 230, respectively in the conduit 64 and the branch
68.
The timing of the activation of the solenoids S2 and S3 are the
same as previously described with respect to FIG. 2, and the fluid
controlling thereby is also the same. However, the timing of the
solenoid S1 is advanced by three-fourth second, as shown in FIG.
10, specifically with reference to time bars 136' and 142' so as to
place the fluid pump 24 in the cocked position in sufficient time
for diluent dispensing to commence at the same times as in the
primary embodiment, i.e., 1 second and 2.5 seconds of the cycle, as
represented by time bars 138' and 146'. Such dispensing is
accomplished on the release of the solenoid S1 which drives the
piston 30 toward the right end of the cylinder 28 (with reference
to FIG. 1).
In the event that the lid 92 and its switch SW1 are replaced by
another form of proximity initiating arrangement, some stray light
might impinge upon the photoresponsive device 106. In such event,
the filter 102 could be located in protective proximity to the
device 106 as illustrated. In all other respects, the embodiment of
FIG. 9 is intended to be the same as that of FIG. 1, and common
reference designations have thus been employed.
It is anticipated that those skilled in the art might find it
advantageous to introduce certain technical changes to suit
particular environmental, testing and measuring need, while at the
same time remaining within the scope of the invention.
* * * * *