US3185447A - Analyzer mixing apparatus - Google Patents

Description

May 25, 1965 c. c. HACH ANALYZER MIXING APPARATUS Filed March 25, 1963 WW1? m m m /m M United States Patent 3,185,447 ANALYZER MIXING APPARATUS Clifford C. Hach, Ames, Iowa, assignor to Hach Chemical Company, Ames, Iowa, a corporation of Iowa Filed Mar. 25, 1963, Ser. N 0. 267,712 3 Claims. (Cl. 259-4) This invention relates to automatic continuous analyzers and more particularly concerns a fluid mixing apparatus for such equipment.

An automatic continuous analyzer of an improved kind is shown in my copending application Serial No. 267,467 filed March 25, 1963. This analyzer reliably mixes a reagent with a fluid sample in controlled proportions and continuously. The resulting mixture is sensed, as for color changes with a colorimeter, toobtain the desired test information.

Some reagents blend less readily with a flowing sample than others, and it is sometimes desirable, in making a test, to smoothly blend one reagent into the sample before adding additional reagents.

Accordingly, it is an object of the invention to provide a mixing apparatus for insuring complete blending of one or more reagents, in desired order, into a fluid sample while maintaining controlled proportions of reagent and sample.

A further object is to provide a mixing apparatus of the above character which is simple and compact so as to be well suited for use in an economical automatic analyzer.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIGURE 1 is a plan of a mixing body constructed in accordance with the invention.

FIG. 2 is a section taken approximately along the line 22 in FIG. 1; and

FIG. 3 is a fragmentary along the line 3-3 in FIG. 1.

While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. On the contrary, I intend to cover all alternatives, modifications, and equivalents which may be included within the spirit and scope of the invention as defined by the appended claims.

Turning now to the drawings, there is shown an apparatus for mixing and blending fluid reagents with a less dense fluid sample in controlled proportions. The apparatus includes a mixing body of generally cylindrical shape and including a wall 16 which defines a sample reservoir 17 surrounded by a trough 18 formed between the wall 16 and an outer wall 19.

The body 15 also includes a center block 20 within the sample reservoir 17 that is bored to form vertically extend ing mixing passages 21, 22 and 23, and to form a discharge passage 24 at approximately the center of the block 20. The discharge passage 24 is provided with a bottom aperture defined by a tube 25 having a center opening 26. The opening 26 is of capillary size or slightly larger, depending upon the sample flow rate desired, as will be discussed below:

A channel 31 connects the bottom of the sample reservoir 17 with the bottom of the mixing passage 21. A channel 32 connects the top of the mixing passage 21 to the top of a down passage 33, and another channel 34 connects the lower portion of the down passage 33 to the bottom of the next mixing passage 22. Similarly, a channel 35 connects the top of the mixing passage 22 to the top of a down passage 36, and the bottom portion of the down passage 36 is connected to the bottom of the mixing pas sage 23 by a channel 37. Finally, a channel 38 connects section taken approximately the top of the third mixing passage 23 to the top of the discharge passage 24.

Thus, the bottom of the sample reservoir 17 is connected to the bottom of the mixing passages 21-23 through the channel 31 and the passages and channel preceding the mixing passages 22 and 23. The tops of the mixing passages 21-23 are connected to the top of the discharge passage 24 through the channel 38 and the passages and channels following the mixing passages 21 and 22.

The fluid sample is introduced into the reservoir 17 through a port 40 at a rate that is greater than the flow rate of the sample through the aperture 26. The channels 32, 35 and 38 lie below the level of the wall 16 so that the fluid sample flows from the reservoir 17 through the channel 31, up the mixing passage 21, over the channel 32, down the down passage 33, through the channel 34, up the mixing passage 22, and so forth to the discharge passage 24, where the fluid flows through the aperture 26 and is discharged from the apparatus (see the arrows in the several figures). Since the fluid sample is added at a rate greater than it can pass through the aperture 26, the excess fluid spills over the wall 16 into the trough 18 and is carried away through a discharge port 41. The wall 16 thus maintains a constant head of fluid relative to the aperture 26 and, hence, the rate of sample flow through the mixing body 15 is determined by the size of the aperture 26 in the tube 25.

Two fluid reagents are added to the flow of fluid sample through the body 15. The first reagent is added through a capillary tube 42 extending down into the reservoir 17 and positioned with the tube end adjacent the channel 31. The second reagent is added through a capillary tube 43 disposed in the down passage 36.- The reagent heads are adjusted relative to the capillary tubes 42, 43 so that reagent flows at a desired rate into the stream of fluid sample. In this way, and by controlling the size of the aperture 26, the proportions of fluid and reagent mixed in the body 15 can be adjusted as required by the particular test to be made.

In operation, the reagents are usually slightly more dense than the fluid sample. The reagent added through the tube 42 thus falls downwardly in the reservoir 17 and is carried with the flowing fluid sample through the channel 31. However, the reagent and sample must move upwardly through the mixing passage 21, and it has been found that the slightly more dense reagent, being carried upwardly by the fluid stream moving in the mixing passage 21, is effectively dispersed and smoothly blended throughout the fluid sample. It will be noted that the combined reagent and sample is again carried, via the channels 32, 37 and the down passage 33, to a second mixing passage 22 which again requires that the slightly heavier reagent be lifted by the flowing fluid sample to the next channel 35. The second upward movement of the sample and reagent insures complete mixing and blending. The stream then moves downwardly through the down passage 36 and the second reagent is added through the tube 43. This reagent is blended as the fluid flows through the channel 37 and upwardly in the mixing passage 23. As a result, the fluid being discharged at a controlled rate through the aperture 26 is a smoothly blended mixture of the fluid sample introduced through the port 40 and the two reagents introduced through the tubes 42, 43.

It will, of course, be evident that the order of adding reagents and the number of reagents added can be varied, depending upon the test being performed. The significant feature of the apparatus is the creation of an upwardly moving stream of fluid sample to insure complete and smooth blending of the test reagent which has been added to the stream. The simplicity, compactness, and economy of the mixing body 15 will be readily apparent. Those skilled in this art will also appreciate how the apparatus 16 can be embodied in automatic analyzing apparatus of the character shown in my copending application identified above.

I claim as my invention:

1. A one piece mixing body for analyzer apparatus comprising an integral wall defining a sample reservoir, said body having a first hole defining a discharge passage adjacent said reservoir with an aperture at the bottom of the passage, said body having a second hole defining a ver tically extending mixing passage adjacent said reservoir and said discharge passage, and said body having relieved portions defining channels interconnecting the bottom of said reservoir with the bottom of said mixing passage and the top of said mixing passage with the top of said discharge passage.

2. In an analyzer, apparatus for mixing and blending a fluid reagent with a less dense fluid sample in-controlled proportions comprising, in combination, means defining a sample reservoir, a discharge passage, and a mixing pas sage, means providing a bottom aperture in said discharge passage, means interconnecting the bottom of said reservoir with the bottom of said mixing passage and the top of said mixing passage with the top of said discharge passage, means for supplying a fluid sample to said reservoir at a rate greater than the flow rate through said aperture, and a capillary tube extending into said reservoir with its lower end adjacent said means interconnecting the bottom of the reservoir for delivering reagent into the stream of sample flowing from said reservoir to said mixing passage.

3. In an analyzer, apparatus for mixing and blending a fluid reagent with a less dense fluid sample in controlled proportions comprising, in combination, a mixing body having, in horizontally spaced relation, a sample reservoir, a discharge passage, and a mixing passage, said body having a bottom aperture in said discharge passage, said body also having channels interconnecting the bottom of said reservoir with the bottom of said mixing passage and the top of said mixing passage with the top of said discharge passage, means for supplying a fluid sample to said reservoir, and thus to said discharge passage through said channels, at a rate greater than the flow rate through said aperture, and a capillary tube extending into said reservoir with its lower end adjacent said channel to said mixing passage for delivering reagent into the stream of sample.

References Cited by the Examiner UNITED STATES PATENTS 2,440,623 4/48 Voorhees 214-152 CHARLES A. WILLMUTH, Primary Examiner.

Claims (1)

1. AT ONE PIECE MIXING BODY FOR ANALYZER APPARATUS COMPRISING AN INTEGRAL WALL DEFINING A SAMPLE RESERVOIR, SAID BODY HAVING A FIRST HOLE DEFINING A DISCHARGE PASSAGE ADJACENT SAID RESERVOIR WITH AN APERTURE AT THE BOTTOM OF THE PASSAGE, SAID BODY HAVING A SECOND HOLE DEFINING A VERTICALLY EXTENDING MIXING PASSAGE ADJACENT SAID RESERVOIR AND SAID DISCHARGE PASSAGE, AND SAID BODY HAVING RELIEVED PORTIONS DEFINING CHANNELS INTERCONNECTING THE BOTTOM OF SAID RESERVOIRS WITH THE BOTTOM OF SAID MIXING PASSAGE AND THE TOP OF SAID MIXING PASSAGE WITH THE TOP OF SAID DISCHARGE PASSAGE.

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