U.S. patent number 3,695,281 [Application Number 05/089,753] was granted by the patent office on 1972-10-03 for method and apparatus for fluid injection.
This patent grant is currently assigned to Technicon Instruments Corporation. Invention is credited to Luis P. Leon.
United States Patent |
3,695,281 |
Leon |
October 3, 1972 |
METHOD AND APPARATUS FOR FLUID INJECTION
Abstract
A fluid injection device for incorporation in automated
apparatus for the quantitative analysis of a substance transported
in a flowing liquid stream segmented by gas bubbles or other
immiscible fluid segments. The device includes a body defining an
elongated fluid passageway portion. One end of the passageway
portion provides an inlet for fluid or gas under pressure through a
tube extending into the passageway portion from the last-mentioned
end toward the other end thereof, which tube has a discharge end
portion received axially within the passageway portion. An inlet
for unsegmented liquid under pressure communicates with the
passageway portion, upstream of the aforementioned discharge end
portion of the tube, providing for axial injection of gas into the
stream of liquid flowing from the liquid inlet toward the other end
of the passageway portion. By varying the resistance to liquid flow
in the area around the discharge end of the tube the size of the
bubbles injected into the liquid stream may be changed.
Inventors: |
Leon; Luis P. (Ossining,
NY) |
Assignee: |
Technicon Instruments
Corporation (Tarrytown, NY)
|
Family
ID: |
22219423 |
Appl.
No.: |
05/089,753 |
Filed: |
November 16, 1970 |
Current U.S.
Class: |
137/1; 73/864.81;
137/154; 137/602 |
Current CPC
Class: |
F16K
11/00 (20130101); Y10T 137/0318 (20150401); Y10T
137/87571 (20150401); Y10T 137/2931 (20150401) |
Current International
Class: |
F16K
11/00 (20060101); F16k 019/00 (); F17d
001/08 () |
Field of
Search: |
;137/1,13,154,602,604
;23/23A,253A ;73/53,423A ;259/4 ;356/179,181 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nilson; Robert G.
Claims
What is claimed is:
1. A fluid injection device for a continuous-flow sample analysis
system utilizing at least one segmented liquid stream in a
utilization conduit, comprising: a first unobstructed fluid
passageway conduit for laminar liquid flow therethrough, having an
inlet and having an outlet connected to said utilization conduit, a
second unobstructed fluid passageway conduit extending a distance
inwardly into a portion of said first fluid passageway conduit of
uniform diameter, having an outlet axially directed within said
portion of said first fluid passageway conduit in a direction
toward and terminating short of said first passageway conduit
outlet, said second passageway conduit having an inlet without said
first passageway conduit, said inlet of said first passageway
conduit being adapted to receive a stream of unsegmented liquid,
said inlet of said second passageway conduit being adapted to
receive a stream of segmenting fluid immiscible with said liquid,
and said outlet of said first passageway conduit being adapted to
discharge segmented liquid, and means in said first conduit,
downstream from said second conduit outlet, creating a
predetermined resistance to flow of said fluid from the
last-mentioned outlet, thereby determining the size and frequency
of the segments of said immiscible fluid.
2. A method of injecting a fluid into a stream of liquid immiscible
therewith for utilization in a sample analysis system comprising:
flowing a first stream constituted by a liquid under pressure on a
path toward an analysis utilization conduit, injecting axially into
said first stream a second stream flowing in the same direction as
said first stream to segment the latter, which second stream is
constituted by a fluid under pressure which is immiscible with said
liquid, and creating by confinement a predetermined resistance to
flow of said first stream in the area where said second stream is
injected into said first stream, thereby determining the size and
frequency of the segments in said first stream.
3. The method of claim 2, wherein: there is provided a conduit for
said second stream having an inlet and having an outlet, and said
first stream is flowed along and around the outlet portion of the
last-mentioned conduit.
4. The method of claim 2, wherein said second stream is injected
concentrically into said first stream.
5. A method of injecting a fluid into a stream of liquid immiscible
therewith for utilization in a sample analysis system comprising:
flowing a first stream constituted by a liquid under pressure on a
path toward an analysis utilization conduit, injecting axially into
said first stream a second stream flowing in the same direction as
said first stream to segment the latter, which second stream is
constituted by a gas under pressure which is immiscible with said
liquid, and creating by confinement a predetermined resistance to
flow of said first stream in the area where said second stream is
injected into said first stream, thereby determining the size and
frequency of the segments in said first stream.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a device, useful in automated
quantitative analysis of samples flowing in a liquid stream, for
adjustably injecting gas bubbles or other immiscible fluid segments
into the stream in a manner to control the size and frequency of
the injected bubbles or segments, the size and frequency being
interdependent.
2. Prior Art
In analysis systems of this kind, a flowing stream of sample
liquid, which stream may be a continuous monitoring stream, or a
stream of sequential liquid samples, may be continuously mixed in a
predetermined proportion with one or more reagents, and otherwise
processed to provide a color reaction, for example, the optical
density of which at a particular wave length is responsive to the
concentration of a constituent of interest in the original sample.
Such a system is disclosed in Skeggs U.S. Pat. No. 2,797,149 issued
June 25, 1957. Customarily, the flowing stream of sample plus
reagent is divided into sequential segments, each succeeding
segment of sample plus reagent being spaced from the preceding
segment by a gas segment. Each segment of sample plus reagent is
then mixed as it flows along in the stream, as shown for example in
Ferrari, Jr. U.S. Pat. No. 2,933,293 issued Apr. 19, 1960. The
streams of sample and reagent are supplied in a predetermined
proportion to a junction by a peristaltic proportioning pump such
as is shown in Bilichniansky et al. U.S. Pat. No. 3,425,357 issued
Feb. 4, 1969 wherein it is pointed out that a transient change in
proportions between the sample and the reagent or reagents may
affect the accuracy of the analysis system, which accuracy is
premised on constant proportions, referring to the solution to this
problem taught by earlier Smythe U.S. Pat. No. 3,306,229 issued
Feb. 28, 1967.
U.S. Pat. No. 3,425,357, supra, illustrates and describes apparatus
tending to provide in use, over a given range of flow rates,
identical liquid segments of sample plus reagent by the provision
of substantially uniform periodic gas segments between the liquid
segments, and which apparatus is susceptible of some adjustment to
vary the size of the gas segment. The aforementioned adjustment may
not be made on a single pump tube but may be made only
simultaneously with reference to all of a family of pump tubes.
Moreover the control of gas bubble patterns is not sufficiently
fine in at least some analysis systems to meet requirements.
Modern analysis systems, making up to twelve or more tests on a
single sample, employ very small quantities of sample for a single
test and concomitantly small volumes of reagents. Hence, the
control of proportions has become even more critical. In this
connection, a need has arisen for a device to control liquid
segmentation very closely and a need has also arisen to control the
gas segmenting pattern in a plurality of liquid streams
independently of one stream to another.
While reference has been made to the use of gas as a liquid
segmenting fluid it is to be understood that the fluid need not be
a gas in at least certain applications but may be a liquid
immiscible with the liquid which it segments. It is now well known
that segmenting fluids are used in sample analysis apparatus of the
automated type to occlude and cleanse the wall structure of the
conduit in which the particular segmented stream flows and to
maintain the integrity of each slug of liquid used for analysis
purposes so that each will not contaminate the next succeeding one
or be contaminated by the one which it follows.
SUMMARY OF THE INVENTION
One object of the invention is to provide an improved fluid
injection device for use in automated apparatus for sample analysis
of the continuous flow type such as characterized above. Another
object is to provide a fluid injection device for segmenting any
liquid with a fluid immiscible with the liquid such as a gas or
another liquid, which device injects such fluid axially into the
moving stream of liquid to be segmented. Still another object is to
provide such a fluid injection device for each one of a plurality
of segmented streams so that the operation of one is not dependent
on the operation of another. A further object is to provide a fluid
injection device which injects a gas, for example, into a liquid
stream to segment the stream, the gas being in the form of bubbles,
wherein the resistance to liquid flow acts to vary the bubble size
and thereby the frequency of the gas bubbles within certain
limits.
A further object is to provide a fluid injection device which
includes a body defining an elongated fluid passageway portion. One
end of the passageway portion provides a fluid or a gas inlet for
gas under pressure through a tube extending into the passageway
from the last-mentioned end toward the other end thereof, which
tube has a discharge end portion received with clearance
concentrically within the passageway portion. An inlet for
unsegmented liquid under pressure communicates with the passageway
portion upstream of the aforementioned discharge end portion of the
tube, providing for a concentric injection of gas into the stream
of liquid flowing from the liquid inlet toward the other end of the
passageway portion, and wherein the resistance to liquid flow in
the area around the discharge end of the tube may be changed to
vary the size of gas bubbles injected into the liquid stream.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
FIG. 1 is an end view of a fluid injection device shown in
elevation, embodying the invention, showing the left end of the
device as illustrated in FIG. 2;
FIG. 2 is a side elevational view, partially in section; and
FIG. 3 is a view illustrating a detail of the construction,
partially in section.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawing, the body of the fluid injection device is indicated
generally at 10. It may be formed of a clear, hard plastic
material, by way of example, such as one sold under the trademark
Plexiglas. As shown in the drawing, its vertical dimension shown in
FIG. 2 is greater than its width shown in FIG. 1, and it is
elongated horizontally as shown in FIG. 2. As shown, the end of the
body remote from that illustrated in FIG. 1 is undercut at 11 as
shown in FIG. 2. As shown in the last-mentioned view, adjacent the
last-mentioned end of the body there is provided a vertically
elongated opening 12 extending through the body from one side
through the other.
The body has a longitudinal bore 14 extending therethrough
approximately midway between the upper and lower extremities
thereof and interrupted by the opening 12. The right end portion of
this bore as viewed in FIG. 2 is threaded, as at 16, this threaded
portion extending through the right end of the body into the
opening 12.
Also, as shown in FIG. 2, a portion of the bore, extending left
from the interruption created by the opening 12, is threaded and
indicated at 18. The bore 14, has a portion 20 thereof extending to
the left as viewed in FIG. 2. The bore portion 20 is smooth and has
a uniform diameter throughout the length thereof.
The bore portion 20 merges with a smaller smooth bore portion 22
extending to the left as viewed in FIG. 2. A shoulder 24 is formed
at the junction of the bore portions 20 and 22 for a purpose which
will appear hereinafter.
Again extending to the left as viewed in FIG. 2, the bore portion
22 merges with portion 26 through a bore portion 28 in the
illustrated form. In the illustrated embodiment, the bore portions
26 and 28 constitute a restriction. The bore 14 at its left end as
viewed in FIG. 2 terminates in a portion 30 which may be of larger
cross section and receive a suitable nipple for connection to a
fluid line, neither being shown.
Another bore is provided in the body 10 and indicated generally at
32. In the illustrated form, the bore 32 extends through the upper
extremity of the body 10 and is provided with a portion 34 similar
to the portion 30 of the bore 14 previously described. The bore 32
communicates with the bore portion 22 of the bore 14 as shown in
FIG. 2. As shown in the last-mentioned view, the point of entry of
the bore 32 into the bore portion 22 is in the central portion of
the latter, that is approximately midway between the ends of the
portion 22. The bore portion 34 may receive a suitable nipple for
connection to a fluid line, neither being shown.
A tube 36 is provided in axial relation to the bore portion 22 and
extending thereinto. In the form illustrated by way of example, the
tube 36 is supported concentrically with clearance in the portion
22 of the bore 14, the tube having a discharge end 37 and having an
inlet end 39 beyond the bore 14, as shown in FIG. 2, for suitable
connection to a conventional conduit, now shown. The tube 36
extends through and is fixed to a screw member 38 in axial and
concentric relation thereto. The screw member 38, best shown in
FIGS. 2 and 3, provides a rigid support for the tube 36 and is
threadedly received in the bore portion 16 for axial adjustment
therein. The screw member 38 has a radial flange 40 to be gripped
for manipulation and adjustment of the axial position of the tube
36 with the screw member 38. Both the tube 36 and the screw member
38, but particularly the tube, should be formed of a suitable
corrosion-resistant metal such as platinum or stainless steel for
example.
The tube 36 passes through a sealing element 42 of sleeve form and
structured of a suitable elastomer material such as silicone rubber
for example. The sealing element 42 is received in the bore portion
20 and bottoms on the aforementioned annular shoulder 24. The
sealing element 42 is compressed to form a seal between the body 10
and the tube 36 by a thrust element 44 of sleeve-like form formed
of a suitable hard plastic or metal, which embraces the tube 36 and
extends into the bore portion 20 from the right of the sealing
element 42 as shown in FIG. 2. The right end of the thrust element
44 receives pressure axially thereof from a clamping member 46.
The clamping member 46, also formed of a suitable
corrosion-resistant metal, is of cylindrical cross section and has
an axial bore extending concentrically therethrough which slidably
receives the tube 36, permitting axial adjustment of the tube 36
with reference to the member 46. The clamping member 46 has an
externally threaded portion threadedly received in the bore portion
18 for axial adjustment therein. The inner end of the clamping
member bears against the right end of the thrust element 44, as
previously indicated, and the member 46 is provided with a radial
flange 48 accessible in the opening 12 in the body to be gripped
and manipulated for adjustment purposes of the sealing pressure of
the seal effected by the element 42 between the body 10 and the
tube 36.
It will be understood from the foregoing that, when it is desired
to adjust the axial position of the tube 36, the sealing pressure
between the tube and the body may be relieved first, if necessary
for axial movement of the tube 36, by manipulation of the clamping
member 46. After this is done the tube adjusting member 38 may be
manipulated as aforesaid to vary the axial position of the tube 36
carried thereby. The clamping member 46 may then be re-tightened to
provide the aforementioned seal between the tube and the body in
the desired axial position of the tube. The radial flange 40 of the
adjusting member 38 may have on its outer face circumferentially
spaced radial lines, not shown, to selectively index with a
suitable reference line, not shown, on the overhanding surface 50
of the body, for the purpose of indicating the axial position of
the tube 36.
Broadly considered, liquid delivered under pressure to the inlet of
the passageway 32 to be segmented may be any liquid, which includes
sample streams and reagent streams but is not limited thereto, with
which liquid it is desired to provide an interface with a fluid
immiscible therewith. The liquid to be segmented may be delivered
in any conventional manner as from a pressurized container of such
liquid or from a suitable pump such as that illustrated and
described in U.S. Pat. No. 3,425,357, supra, or of the type of
Ferrari, Jr. et al. U.S. Pat. 2,935,028 issued May 3, 1960. The
immiscible fluid for segmentation of the liquid stream is also
delivered under pressure to the inlet end of the tube 36, as
previously indicated.
The immiscible fluid, which may be a gas, may be delivered to the
last-mentioned inlet from a source of such fluid in a pressurized
container or may be delivered by a suitable pump of the type of
U.S. Pat. No. 2,935,028 supra, or of the type of U.S. Pat. No.
3,425,357. Whatever the source of pressure, that is, independently
thereof, the gas line to the inlet of tube 36 may be valved in the
manner of U.S. Pat. No. 3,425,357, supra, so as to be pulsed to the
last-mentioned tube inlet. As previously indicated, the fluid
injection device shown by way of example in the drawing may be used
in any or as many liquid lines of analysis apparatus as require
segmentation, one such device being used in each such liquid line.
The segmented stream is discharged from the device through the bore
portion 30.
From the foregoing, it will be evident that the bore portions 22,
28, 26 and 30, constitute an elongated passageway portion. One end
of the last-mentioned portion provides an inlet for fluid or gas
under pressure through the tube 36 extending into the passageway
portion from the last-mentioned end toward the other end thereof.
The bore or passageway 32 provides an inlet for unsegmented liquid
under pressure, communicating with the passageway portion upstream
of the discharge end 37 of the tube, providing for concentric
injection of gas into the stream of liquid flowing from the liquid
inlet toward the discharge end 30 of the passageway portion.
The operation of the fluid injection device will now be described.
With the discharge end of the tube 36 in the position shown in FIG.
2, extending beyond the junction of the passageway portions 14 and
32 toward the aforementioned liquid outlet, liquid under pressure
entering the passageway portion 14 from the passageway portion 32
flows around the tube 36 as it passes in a direction toward the
discharge end of the passageway 14. As this occurs, immiscible
fluid, say, gas, is discharged concentrically from the discharge
end of the tube 36 into the stream of liquid. Hence a bubble
ballons out of the tube in a longitudinal direction toward the
outlet of the passageway 14, with liquid flowing around it.
The bubble is eventually sheared off the tube 36 and passes
downstream in the bore portion 26 and beyond followed by a portion
of the liquid stream, while another bubble builds from the tube 36.
It has been found that gas bubbles formed in this manner are much
more uniform in size than those formed customarily by injecting one
fluid into another in a right angular relationship. The frequency
of bubbles, or the bubble pattern in a segmented liquid, is also
more uniform when the injection is made concentrically according to
the invention.
Bubble size is important in sample analysis apparatus. Of course,
the bubbles must be of a size to occlude analysis tubing to
maintain the integrity of liquid segments. Bubbles must also reach
a greater diameter than the inner diameter of the conduits used in
analysis in order to cleanse the wall structure of such conduits
properly. On the other hand, bubbles in such conduits should not be
unduly elongated as such bubbles, which have no analysis function,
only delay analysis, and because their friction with such conduit
wall structures creates undesirable resistance to flow.
With constant flow rates of the liquid and the immiscible fluid to
the injection device, the size of the bubbles, together with their
frequency, may be varied by adjusting the outlet of the tube 36
toward or away from the narrowed bore portion 26 from the position
of FIG. 2. Within practical limits, when the adjustment is away
from the bore portion 26, the resistance to liquid flow lessens and
the bubbles become larger and the interval therebetween
correspondingly longer; and when the adjustment is in the other
direction, increasing the resistance to liquid flow, the bubbles
become smaller and the interval therebetween smaller. Initially,
for given flow rates, the size of bubbles formed is dependent on
the ratio of the liquid flow rate to the immiscible fluid flow
rate, these being delivery rates to the injection device. The
higher the liquid flow rate is to the immiscible fluid flow rate,
the smaller the bubbles become. The greater the resistance is to
liquid flow in the passageway portion 22, the smaller the bubbles
of gas become.
For illustrative purposes only, the internal diameter of the tube
36 may be approximately 0.020 inch, and the bore portion 26 of the
passageway 14 may be of approximately the same diameter. The
clearance between the tube 36 and the bore portion 22 of the
passageway 14 may be approximately 0.001 inch.
Though not limited thereto, the passageway 32 of the fluid
injection device may be considered a conduit for a reagent to be
segmented before the confluence of the reagent stream and a sample
stream. If desired, a sample stream inlet bore, not shown, may be
included in the fluid injection device communicating with the
passageway 14 downstream from the inlet end of the bore portion
26.
As previously indicated, the apparatus disclosed in the drawing is
for the purpose of example only. The method of injecting a fluid
into a stream of liquid immiscible therewith comprises flowing a
first stream constituted by a liquid under pressure on a path so
that it flows along and around the discharge end portion of a
conduit, and flows beyond the last-mentioned end portion toward an
analysis utilization conduit, and flowing a second stream through
the first-mentioned conduit in the same direction as the first
stream to segment the latter, which second stream is constituted by
a fluid under pressure which is immiscible with the liquid. The
method further comprises predetermining the resistance to flow of
the first stream around the discharge end of the first-mentioned
conduit to thereby determine the size and frequency of the segments
in the first stream.
The precision with which the injection device functions in sample
analysis apparatus for proper proportioning of liquids, and the
precision with which it forms immiscible fluid segments of the
desired size are significant advantages. The feature of the device
which permits the adjustment of size of, say, bubbles, within
previously established flow rates is highly advantageous for
reasons previously brought out.
It is believed that many advantages of this invention will now be
apparent to those skilled in the art. The foregoing description is
illustrative, rather than limiting, as a number of variations and
modifications may be made without departing from the true spirit
and scope of the invention. The invention is limited only by the
scope of the following claims.
* * * * *