US 3726297 A
Method and device for introducing for mixing a first liquid into a second liquid for use in automated apparatus for the quantitative analysis of a treated substance. The device includes a body defining an elongated passageway portion. One end of the passageway portion provides an inlet for the first liquid, and the other end provides an outlet for the first liquid to which the second liquid has been admixed in the passageway portion. A tube, carrying the second liquid in a countercurrent direction, has a discharge end directed axially within the passageway portion and spaced from the wall structure thereof for mixing impact of the two liquids in substantially the central area of the passageway portion, and so arranged that the intermixed liquids flow around the last-mentioned tube end substantially throughout the cross section of the cavity between the tube and the passageway portion before exiting from the last-mentioned portion.
Description (OCR text may contain errors)
United States Patent [191 Heimann et all.
 METHOD AND DEVICE FOR INTRODUCING FOR MIXING A FIRST LIQUID INTO A SECOND LIQUID  Inventors: Richard H. Heimann,
Aaron Kassel, Tarrytown; Donald F. Kopelman, New York, all of N.Y.
 Assignee: Technicon Instruments Corporation,
 Filed: Apr. 14, 1971  Appl.No.: 133,989
137/604, 73/423 A  Int. Cl. ..Fl7d 1/08, Fl6k 19/00  Field of Search ..137/1, 13, 154, 602,
137/604; 23/230 A, 253 A; 73/53, 423 A; 259/4; 356/179, 181
2,933,293 4/1960 Ferrari, Jr. ..259/4 Flushing;
[451 Apr. 10, 1973 8/1970 Hrdina ..137/154 X Primary Examiner-Robert G. Nilson Attorney-Tedesco & Rockwell [57 ABSTRACT Method and device for introducing for mixing a first liquid into a second liquid for use in automated apparatus for the quantitative analysis of a treated substance. The device includes a body defining an elongated passageway portion. One end of the passageway portion provides an inlet for the first liquid, and the other end provides an outlet for the first liquid to which the second liquid has been admixed in the passageway portion. A tube, carrying the second liquid in a countercurrent direction, has a discharge end directed axially within the passageway portion and spaced from the wall structure thereof for mixing impact of the two liquids in substantially the central area of the passageway portion, and so arranged that the intermixed liquids flow around the last-mentioned tube end substantially throughout the cross section of the cavity between the tube and the passageway portion before exiting from the last-mentioned portion.
10 Claims, 3 Drawing Figures PATENTEDAFRIOIQYS 3,726,297
FIG. 1 PRIOR ART INVENTORS RICHARD H. HEIMANN AARON KASSEL DONALD F. KOPELMAN ATTORNEY METHOD AND DEVICE FOR INTRODUCING FOR MIXING A FIRST LIQUID INTO A SECOND LIQUID BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method and device for introducing for mixing a first liquid into a second liquid for use in automated apparatus for the quantitative wet-chemical analysis of a treated substance.
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 propor tion with one or more reagents, and otherwise processed to provide a color reaction, for example, the optical density of which at a particular wavelength 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, I957. Skeggs et al. U.S. Pat. No. 3,241,432 issued Mar. 22, 1966 shows and describes apparatus for performing multiple different tests on each of a series of samples.
Customarily, the flowing stream of sample plus reagent and, perhaps, diluent is divided into sequential segments, each succeeding segment of sample plus additions being spaced from the preceding segment by a segment of gas or other immiscible fluid. Each segment of sample plus any addition thereto is then mixed, as in a mixing coil, as it flows along in the stream such as shown and described in Ferrari, Jr. U.S. Pat. No. 2,933,293 issued Apr. 19, 1960. In todays systems it is often necessary to intermix other liquids such as two or more reagents or a diluent and a reagent, for example.
Prior to being intermixed, the streams of sample and reagent, for example, are supplied in predetermined proportions to a junction as by a peristaltic proportiom ing pump such as shown and described in Bilichniansky et al U.S. Pat. No. 3,425,357 issued Feb. 4, I969. The stream of sample, which may be segmented, may be supplied from a turntable supporting a series of liquid samples in cups as shown and described in Skeggs U.S. Pat. No. 2,879,141 issued Mar. 24, 1959.
Today, in many hospitals, for example, there is a need for automated quantitative analysis apparatus which will accurately and speedily perform a large number of different tests on each one of a large number of different samples, as in the analysis of human blood samples. It is desired that up to l2 different tests or more be made on such apparatus on each of 60 or more different samples within a period of an hour. Such desirable systems must inherently employ miniscule amounts of each sample for each test and a correspond- -ing volume of reagent. The speed of mixing liquids together is critical to the fast performance of any such apparatus which carries out the tests and then records the results.
It is often desired to intermix two liquids in a stream prior to the introduction of a third liquid downstream and upstream from a mixer such as a mixing coil. It may also be desirable to maintain the points of confluence of the last-mentioned liquids at a short distance apart in a stream for fast execution of a test by such apparatus. It is desirable that the first two liquids, which may react with one another, mix and commence any reaction therebetween as soon as possible after the confluence of the streams of the first and second liquids, and for this to occur it is necessary that the two streams be intermixed substantially thoroughly at the point of confluence.
Heretofore, such instantaneous substantially thorough mixing at the confluence of such streams has not taken place in analytical apparatus such as described as far as is known. It has been the practice to bring the confluence of two such streams together at approximate right angles and to then flow the resultant stream in the same direction as the direction of inflow of one of the aforementioned converging streams. When a liquid to be admixed in this fashion in another liquid is introduced in this manner it tends to flow along that part of the wall structure of the conduit in which it was introduced and not mix thoroughly with the other liquid unless or until the two liquids are passed through a mixer such as a coil. Of course, the flow of the stream through one or more mixing coils or even through a static mixer, such as shown and described in Dannewitz et al. U.S. Pat. application Ser. No. 60,474, filed Aug. 3, I970 and assigned to the same assignee as the instant invention, delays the transit of the stream to the analysis station of the apparatus.
SUMMARY OF THE INVENTION One object of the invention is to provide an improved method and device for introducing for mixing one liquid into another liquid in a manner to cause impact of one on the other for a mixing effect for use in automated apparatus for the quantitative analysis of a treated substance. It is within the purview of the invention that one of the liquids may be segmented as by gas bubbles and that the other liquid may be added to the first liquid according to the technique without disturbing the segmentation of the stream.
In accordance with the invention, there is further provided a body defining a walled, elongated fluid passageway portion having an inlet end for a first liquid supplied at a substantially constant flow rate and having an outlet end. A tube is provided having an inlet for a second liquid at a substantially constant but slower flow rate and at a pressure in excess of the pressure of the inflowing first liquid. The tube, which carries the second liquid for admixture with the first liquid, has a discharge end portion directed axially within the aforementioned passageway portion intermediate the inlet and the outlet of the latter and spaced from the wall structure thereof. The discharge end portion of the tube extends in a countercurrent direction to the direction of flow of the first liquid for impact mixing of the liquids in the aforementioned passageway portion and flow of the mixture around the tube discharge end portion prior to exit of the mixture from the aforesaid passageway portion outlet.
BRIEF DESCRIPTION OF THE DRAWING lustrated somewhat diagramatically for introducing for.
mixing a first liquid with a second liquid, embodying the invention; and
FIG. 3 is a sectional view taken on line 3-3 of FIG. 2.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the aforementioned prior art technique of bringing together at a junction two streams of liquid to be subsequently mixed there is shown in FIG. 1 by way of example a block of any suitable material for forming passageways therein for fluids which may be corrosive. The block may be structured of a material sold under the trademark Lucite, for example. The block 10 has a bore 11 therethrough and a smaller bore 12 extends through one face of the block into communication with the bore 1 1.
A stream of liquid is caused to flow in a conventional manner through the bore 11 in the direction of the arrows shown in the last-mentioned view. This liquid is shown as having segments 13 separated from one another by segments 14 of an immiscible fluid which may be a gas. The segments 14 are inert and may take the form of air bubbles, for example, introduced in a conventional manner into the stream prior to introduction of the stream into the bore 11 and of a size to completely occlude the bore. The segmented stream may be considered by way of example as a stream of reagent liquid to which another liquid is to be admixed subsequent to introduction into the bore 11 through the bore 12.
As shown in FIG. 1, a liquid suitably supplied for laminar flow enters the bore 11 from the bore 12 which liquid, indicated at 15, may be considered for purposes of illustration as a sample. It will be seen in this view that the liquid 15 introduced into the bore 11 in which the segmented reagent flow tends to lie along the area of the point of its introduction into the bore 11 as it flows with the reagent stream toward the aforementioned analysis station. In other words, the two streams do not tend to mix as clearly shown in this view, and if the two streams are carried in a common conduit in a straight line downstream from the block 10 for a distance of a foot or more the reagent stream of liquid and the admixed sample stream tend to remain in substantially the same separated condition as shown in FIG. 1. Of course, some liquids mix more readily than others.
This process observed on closed circuit television, has indicated that the sample liquid 15 tends to pile up to a small extent on the leading edges of the bubbles 14 as shown in FIG. 1. It will be understood that the passageways l1 and 12 shown in FIG. 1 may be structured of lengths of glass tubing if desired rather than formed in a block as shown. 4
In the device shown in FIGS. 2 and 3 embodying the invention there is provided a block 16 similar to the block 10 and having a passageway portion, indicated generally at 18, extending therethrough having an inlet end 20 and an outlet end 21. A liquid such as a reagent, for example, is caused to flow in a conventional manner into the inlet 20 and out the outlet 21. The direction of flow is indicated by the arrows. This liquid may be segmented as shown by segments of an immiscible fluid such as inert gas bubbles 22. Such bubbles may be formed of air or nitrogen for example. The segments 22 may be formed of a liquid immiscible with the reagent, provided that such segments do not have a tendency to break up while passing through the passageway portion 18 in a manner to be described hereinafter. It is also to be understood that the laminar stream entering the inlet 20 may be unsegmented within the purview of the invention and the stream may be formed of a liquid other than a reagent such as a diluent or a sample for example.
A tube 24 constructed of a non-corrosive material extends into the passageway portion 18 to carry a liquid to be admixed with the liquid entering the inlet 20 and directed by the tube in a countercurrent direction to the stream entering the last-mentioned inlet so that impact is created between the liquid flowed through the tube 24 and the liquid which has entered the inlet 20. This impact creates a turbulence in the respective liquids which effects substantially thorough mixing of the liquids at this point in their travel and prior to their combined exit through outlet 21.
The liquid, which may be supplied to the tube 24 in any conventional manner for admixture with the liquid flowing between the inlet 20 and the outlet 21, may be a sample, for example, or may be a reagent or a diluent. Like the stream entering the inlet 20, the liquid flowing in the tube 24 may be segmented if desired, although, if this is the case, segments in the liquid traveling in the tube 24 and discharged therefrom will disturb the segmentation pattern formed by the segments 22 in the liquid entering the inlet 20. Of course, the segmentation of the liquid entering the inlet 20 may be omitted as previously indicated.
At least primarily for the purpose of ease of assembly of the tube 24 in the passageway portion 18, the passageway portion is elbowed as shown to provide arm parts 26 and 28. The tube 14 is inserted into the arm part 26 with which the inlet 20 is associated through the elbow of the passageway portion 18 as shown in FIG. 2. The tube 24 has an inlet, as at 30, and an outlet or discharge end 32. As shown, the discharge end portion of the tube 24 is spaced from the wall structure of the passageway portion 18 and may be concentric therewith. It is deemed unnecessary that the tube 24 be absolutely concentric. Such concentricity appears to provide for better mixing of the two liquids but it may be sufficient that the tube extend in the direction shown into the passageway portion 18 only axially and in spaced relation from the wall structure of the portion 18.
It should be noted that the outer surface portion of the tube 24 extending within the arm part 26 and the wall structure of the arm part 26 form therebetween a cavity or chamber in which the flow of the liquid inflowing through the inlet 20 is restricted. This restriction creates a faster flow of fluids in this area toward the outlet 21, and this enhances the mixing effect between the liquids.
Tube 24 has a tight fit within a bore 34 of the block, and the bore 34 is counter-bored, as shown in FIG. 2, to receive a suitable sealing gasket 36 around the tube. The tube 24 extends a sufficient distance into the arm part 26 of the passageway portion to permit the longest anticipated stream segment or bubble 22 to be completely deformed around the tube 24 before the bubble reaches the elbow and must pass from its embracing position around the tube 24 into the arm part 28 of the passageway portion, so as to effectively tend to prevent the breakup of such bubble.
The arm parts 26 and 28 of the passageway portion are illustrated, by way of example only, in right angular relationship to one another with the junction being formed on a radius, as at 38. Because of the elbowed form of the passageway portion 18, the arm part 28 is restricted, as at 40, in the region adjoining the elbow to effectively tend to prevent the breakup of a bubble as it passes through the elbow. It is believed made clear that the gas bubbles 22 effectively maintain the segmentation pattern of the stream isolating liquid segments therebetween while also serving to cleanse the conduit walls as they pass through the device. It should be made clear in this connection that a bubble passing through the passageway portion 18 and deformed by the end 32 of the tube 24 may embrace the tube 24 and substantially encircle it without completely doing so. it is believed that at least rarely does such a deformed bubble form a true annulus around the tube 24.
The cross section of the tube is preferably round but it could be structured as a square, for example, which would indicate, for best performance, that the cross section of the passageway portion 18, which is preferably the same as that of the tube, would also be square.
For illustrative purposes only, the diameter of the passageway portion 18, except for the restriction 40, formed therein may be in the neighborhood of 0.039 inch. The restriction 40 may be in the neighborhood of 0.031 inch in diameter. The tube 24 may have an outer diameter of 0.024 inch and an inner diameter of 0.016 inch for example.
It is believed made clear from the foregoing that the passageway portion 18 could well be provided by glass tubing instead of being formed in a block. As shown, the inlet end 30 of the tube 24 extends a distance from the block 16 for suitable connection to a conduit for the inflow of liquid in the tube 24 as aforesaid. it should be noted that when this liquid is discharged from the end 32 of the tube to impact liquid flowing in the op posite direction into the passageway portion 18 through the inlet 20, the mixing action is such that liquid from the discharge end 32 of the tube tends to mix with the other liquid entirely around the tube 32 as it reverses its direction and flows toward the outlet 21. In this manner, a good mixing action is obtained in the cavity formed between the tube 24 and the wall structure of the passageway portion 18.
It will be evident that the liquid supplied to the inlet 20 should be provided at a substantially constant flow rate, and that the liquid supplied to the inlet 30 of the tube should be provided at a constant but slower flow rate and at a pressure in excess of the pressure of the inflowing liquid at the inlet 20. For illustrative'purposes only, the inflow at the inlet 20 may be at the rate of 0.32 ml/min. of liquid plus 0.1 ml/min. of air in the form of gas bubbles which may number approximately 60/min; The inflow through the inlet 30 of the tube may be 0.03 rnl/min. ofliquid.
While several embodiments of the invention have been described, it will be apparent to those versed in the art that the method and device for introducing for mixing a first liquid into a second liquid for use in automated apparatus for quantitative analysis of a treated substance may take other forms and are susceptible of various changes without departing from the principles of the invention.
What is claimed is:
l. A device for use in a flowing stream of a quantitative wet-chemical analysis apparatus, for introducing for mixing a first liquid into a gas-segmented second liquid having a segmentation pattern, comprising: a body defining a walled generally L-shaped fluid passageway portion having an inlet end for the second liquid supplied at a substantially constant laminar flow rate and having an outlet end, said passageway portion being elbowed and the elbow being formed on a radius, and a tube having an inlet for the first liquid at a substantially constant but slower flow rate and under pressure in excess of the pressure of the inflowing second liquid, said tube, extending into and beyond said elbow, in the central region of said passageway portion, carrying said first liquid for admixture to said second liquid and having a discharge end portion directed in a countercurrent direction to the direction of flow of said second liquid for mixing of the liquid in said passageway portion prior to the exit in laminar flow of the mixture from said passageway portion outlet, without destruction of said segmentation pattern.
2. A device as defined in claim 1 wherein, said tube and said passageway portion define therebetween an annular chamber forming a restriction in said passageway portion to create a faster flow of said liquids, thereby enhancing the mixing effect of said liquids.
3. A device as defined in claim 1 wherein, said passageway portion has in proximity to said elbow a restriction to prevent destruction of said segmentation pattern.
4. A method for use in quantitative wet-chemical analysis of a sample, for introducing for mixing a first liquid into a gas segmented second liquid having a segmentation pattern, comprising the steps of: flowing said second liquid at a substantially constant laminar flow rate into an inlet end of an elongated passageway portion of a first conduit which portion has an outlet end, flowing said first liquid in a second conduit at a substantially constant but slower laminar flow rate and at a pressure in excess of the pressure of the first liquid, and
introducing the second liquid from the second conduit into the central region of the first liquid stream in a countercurrent direction thereto intermediate said inlet and said outlet of said passageway portion, so that said liquids mix with one another in some turbulence without destroying said segmentation pattern prior to exiting from said passageway portion outlet in laminar flow.
5. The method as defined in claim 4, further including the step of restricting the flow of the first liquid immediately downstream from the point of said introduction of the first liquid, thereby creating a faster flow in this region and enhancing mixing of the liquids.
6. The method as defined in claim 4, wherein, said first liquid is a reagent.
7. The method as defined in claim 4 wherein, said first liquid is a sample.
8. The method as defined in claim 4 wherein said first liquid is a diluent.
9. The method as defined in claim 4 wherein said second liquid is a sample.
10. The method as defined in claim 4 wherein said first and second liquids are reagents.