US3419358A - Automatic analysis apparatus and method - Google Patents

Description

1968 w. J. SMYTHE ET AL 3,419,358

AUTOMATIC ANALYSIS APPARATUS AND METHOD Filed Oct. 19. 1965 w 0 cu INVENTORS WILLIAM J. SMY I-IE MORRIS H SHA M05 ATTORNEY United States Patent 3,419,358 AUTOMATIC ANALYSIS APPARATUS AND METHOD William J. Smythe, Rye, and Morris H. Shamos, New

- York, N .Y., assignors to Technicon Corporation, a corporation of New York Filed Oct. 19, 1965, Ser. No. 497,679 6 Claims. (Cl. 23-230) ABSTRACT OF THE DISCLOSURE A large ratio dilution system for an automatic analysis system includes an aspirator vacuum pump which produces a vacuum by the entrainment of gas by a diluent liquid jet, and which has an adjustable input flow of diluent liquid, an aspirator input for the sample liquid to be diluted, and means for adjusting the vacuum pressure at the aspirator input.

This invention relates to the analysis of a continuous stream of liquid. This stream may comprise a plurality of samples transmitted successively, or a continuous monitoring stream.

The stream is customarily treated for analysis, as by dialysis, heating, solvent extraction and by the addition of one or more reagents; and a quantitative measurement for a constituent of interest is obtained by photometric methods, as by colorimetry or flame photometry. The US. Patent 2,797,149 to Leonard T. Skeggs, issued June 25, 1957 is illustrative of methods wherein the sample stream is dialyzed, a reagent is added to the dialyzate producing a color reaction, and the reacted stream is passed through a colorimeter, the light transmittance of the stream at a particular wavelength being responsive to the concentration of a constituent of interest.

Certain applications of continuous analysis require the samples of liquid to be diluted with rather large volumes of a diluent before they can be introduced into the continuous stream for analysis; as for example, when highly corrosive liquids are being analyzed; or when high dilutions are required for colorimetric techniques. Customarily, these dilutions are performed manually.

Dilutions can be performed in the presently known continuous analysis systems. The samples of liquid are initially supplied to the system by a sampler, such as is shown in the US. Patent No. 3,038,340 to Jack Isreeli, issued June 12, 1962. Here an otf-take tube coupled to a pump tube operated by a peristaltic type pump, such as is shown in the US. Patent No. 2,935,028 to Andres Ferrari, Jr., et al., issued May 3, 1960, aspirates the sample from a container into the system. Without resampling, a dilution of l to 100 is sometimes practical. With resampling, it is conceivable that dilutions of l to 10,000 could be achieved. This latter technique is not desirable because a large number of pump tubes is required, the probability of contamination of a suceeding sample by a preceding sample is high, and the consumption of reagents is high.

An object of this invention is the provision of a system wherein dilutions of the order of 1 to 20,000 and 1 to 2,000,000 can be obtained.

Another object of this invention is the provision of dilution system wherein the internal diameter of the offtake line from the sample container is independent of the amount of sample to be ofi-taken into the system, whereby small constrictions which might be clogged by particulate matter are avoided.

Yet another object of this invention is the provision of an all glass, or otherwise corrosion and solvent resistant dilution system, so that highly corrosive or solvent sample liquids may be safely processed.

3,419,358 Patented Dec. 31, 1968 A feature of this invention is the provision of an aspirator vacuum pump which produces .a vacuum by the entrainment of gas by a carrier liquid jet, having an adjustable input flow of carrier or diluent liquid, an aspirator input for the sample liquid, and means for adjusting the vacuum pressure at the aspirator input.

The above and other objects, features and advantages of this invention will be more fully understood from the following description considered in connection with the accompanying illustrative drawing, in which:

The figure is a schematic diagram of an embodiment of this invention.

In the figure, an aspirator vacuum pump 10 is employed to aspirate and dilute a sample liquid supplied in acontainer 12. The diluent is stored in a container 14 into which is mounted acentrifugal pump 16. The pum-p may have a constant volumetric rate output which is supplied through aconduit 18. Theconduit 18 is coupled to aconduit 20 which has a branch conduit 22 controlled by a valve 24 returning to the container 14, and a valve 26. Opening the valve 26 and closing the valve 24 increases the output flow from theconduit 20, while closing the valve 26 and opening the valve 24 decreases the output flow from theconduit 20. The downstream end of theconduit 20 is coupled to the carrier ordiluent input 28 of the aspirator 10.

The aspirator includes ajacket 30 having anaspirator inlet 32, ajet nozzle 34, and anoutput conduit 36 which has areceptacle end 38. In the aspirator here shown the end of the jet nozzle is disposed within the receptacle end of the output conduit. The jet of diluent streaming from thenozzle 34 entraps air therein, reducing the ambient gas pressure within thejacket 30.

Thesample container 12 may be one of a plurality of containers which are mounted on a sampler such as is shown in US. 3,038,340 supra. Each container is sequentially presented to an oil-take tube 40 which is coupled to aconduit 42. The downstream end of theconduit 42 passes through theaspirator inlet 32 and into the airgap between thejet nozzle 34 and thereceptacle end 38 of theconduit 36. The reduced pressure within thejacket 30 provided by the jet of diluent provides a reduced pressure in theconduit 42 which is communicated to the off-take tube 40 which aspirates a stream of sample liquid from thesample container 12. The stream of sample liquid is carried by the stream of diluent through theoutput conduit 36. Theoutput conduit 36 is coupled to the input of .amixing coil 44 whose output is coupled to the input of anautomatic analysis system 46, such as is shown in US. 2,797,149 supra. The input of the system may comprise a pump tube 48 operated by a pump such as is shown in US. Patent No. 2,935,028, issued May 3, 1960 to A. Ferrari, Jr. et al. If less than the total flow from themixing coil 44 is required for analysis, the mixing coil output may be coupled to one leg of a three-legged fitting 50. One of the other legs is coupled to the input of the pump tube 48, and the third leg is coupled to a waste receiver.

The vacuum in theconduit 42 is controlled by avacuum regulator 60. Thepump jacket 30 has an extension formed by asleeve 62. One end of the sleeve is secured onto theaspirator inlet 32; the other end has aplug 64 through which theconduit 42 passes. Thejacket 30, thesleeve 62 and theplug 64 form an air tight enclosure. Theconduit 42 passes, with clearance, through theinlet 32. The vacuum regulator is conveniently provided in the form of a column 66 with a plug 68. Along tube 70, which may be adjusted in height, is passed through the plug 68. Ashort tube 72 is also passed through the plug 68 and is connected to aconduit 74 which is connected to ahypodermic needle 76. The tip of the needle is passed through thesleeve 62. The interior of the column 66 is filled with a liquid such as water. The vacuum developed in the airspace within the column 66 controls the vacuum in thejacket 30, and is determined by the height and the density of the liquid above the lower end of thetube 70.

By making the length of theconduit 42 long enough, the interior diameters of theinlet 32 and theinlet 38 large enough, and thesleeve 62 of a flexible material, such as polyvinylchloride, the off-take tube 40 and theconduit 42 may be integrally formed as a glass tube, and may be swung up and down by acam 43 for insertion and removal of theinlet tube 40 into and from eachsample container 12 presented thereto. Thejacket 30, theconduit 36 and themixing coil 44 may also be integrally formed of glass. Such an all glass sampling system permits the processing of sample liquids of a highly corrosive or solvent nature, since the aspirator 10 permits exceedingly high dilutions, which will make the sample innocuous.

The interior diameters of the oif-take tube 40 and theconduit 42 may be made relatively large since the volumetric rate of flow of the sample liquid can be determined by the diluent flow rate and the setting of thevacuum regulator 60. Thus the interior diameter of the tube and the conduit may be made large enough to avoid clogging which might be caused by a sample liquid containing particulate matter.

A segment of air may be introduced into theconduit 42 between sample container to separate the sample liquids therefrom in the conventional manner.

A wide range of adjustment is possible and the fiows of diluent to sample liquid may be varied so that they are more nearly equal. In this manner the solid glass sampling system may be utilized Without high dilutions of the sample liquid.

In many techniques of colorimetric analysis, it is necessary to utilize highly dilute samples in order to obtain incremental color changes which are responsive to incremental concentration changes. An example of this is: The colorimetric tests for NHS, in the range of -130,000 ppm. Here the sample liquid is initially diluted to approximately 112700, and successively has added to it NaCl, 20% NaOH+4% EDTA, NaPhenate, and NaOCl. Under these circumstances the high dilution factor provided by this invention is very usefull, even though the question of corrosion or solvent resistance is not raised.

While we have shown and described a preferred embodiment of the invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may be made without departing from the underlying ideas or principles of this invention within the scope of the appended claims.

What is claimed is:

1. Liquid sample supply apparatus comprising: an aspirator pump including a jacket forming a closed vessel, a first conduit passing through said jacket having an upstream end for coupling to a source of diluent and a downstream end with said vessel for discharging a stream of diluent within said vessel, a second conduit passing through said jacket having a downstream end for coupling to a mixing means and an upstream end within said vessel for receiving the stream of diluent from said first conduit, whereby the stream will entrap gas within said vessel, a third conduit passing through said jacket having an upstream end for coupling to a source of sample liquid and a downstream end within said vessel for discharging sample liquid into said upstream end of said second conduit, and a fourth conduit in communication with said vessel for limiting the vacuum within said vessel.

2. Liquid sample supply apparatus comprising: an aspirator pump including a jacket forming a closed vessel, a first conduit passing through said jacket having an upstream end coupled to a source of diluent and a downstream end terminating in a nozzle within said vessel for discharging a stream of diluent within said vessel, a second conduit passing through said jacket having a downstream end coupled to a mixing coil and an upstream end Within said vessel forming a receptacle spaced from said nozzle for receiving the stream of diluent from said nozzle, whereby the stream of diluent entraps gas within said vessel thereby lowering the gas pressure within said vessel; a third conduit passing through said jacket having an upstream end coupled to a source of sample liquid and a downstream end within said vessel for discharging sample liquid into said upstream end of said second conduit, which liquid is drawn through said third conduit by the lowered gas pressure within said vessel; and a fourth means in communication with said vessel for limiting the lowered gas pressure within said vessel.

3. Apparatus according to claim 2 wherein said source of diluent includes a constant rate of flow centrifugal pump in communication with a container of diluent.

4. Apparatus according to claim 2 wherein said fourth means includes a vacuum regulator having a conduit coupled through said jacket into said vessel.

5. Apparatus according to claim 2 wherein said mixing coil is integral with said second conduit, and said second conduit, said mixing coil, and said third conduit are made of materials having a high corrosion and solvent resistance characteristic.

6. An automatic method of preparing a sample liquid for automatic analysis comprising: producing a reduced gas pressure in a vessel by passing a jet of a diluent liquid therethrough; adjusting the gas pressure to a predetermined value by passing the jet of diluent liquid adequate to produce a lower gas pressure than desired, and regulating the gas pressure in the vessel to the higher desired value; aspirating the sample liquid as a stream from a supply through a conduit by means of said reduced gas pressure; discharging the aspirated sample liquid into the diluent liquid; withdrawing the added together sample and diluent liquids as a stream; and intermixing the sample and diluent liquids in the stream.

References Cited UNITED STATES PATENTS 2,800,313 7/1957 Targosh et al. 239--318 XR 3,081,158 3/1963 \Vinter 23230 XR 3,211,530 10/1965 Harvey 23-253 3,231,200 1/1966 Heald 239-318 3,333,601 8/1967 Lofgreen 239-318 MORRIS O. WOLK, Primary Examiner.

R. E. SERWIN, Assistant Examiner.

US. Cl. X.R.

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