Apparatus for continuously colorimetrically analyzing fluids for chemical components

995 425

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FLUIDS FOR CHEMICAL COMPONENTS

Filed Dec. 18, 1958

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BY

HANS inventor: FUHRMANN

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ATTYS,

United States Patent Office

2,995,42$

Patented Aug. 8, 1961

995 425

APPARATUS FOR CONTINUOUSLY COLORIMETRICALLY ANALYZING FLUIDS FOR CHEMICAL COMPONENTS

Hans Fuhrmann, Hamburg, Germany, assignor to S.L.F. Engineering Company, Philadelphia, Pa., a partnership

Filed Dec. 18,1958, Ser. No. 781,378

Claims priority, application Germany Dec. 24,1957 4 Claims. (Cl. 23—253)

The present invention relates broadly to apparatus for determining continuously chemical components or constituents in fluids, and more particularly to apparatus for continuously and automatically determining chemical components in fluids by colorimetric analysis.

Heretofore apparatus has been utilized to determine chemical contents of fluids in a continuous and fully automatic process by introducing reagents, indicators, buffers and the like into, or into contact with, a fluid having chemical components therein. Such apparatus have been utilized to test for hardness of water for different applications, silica, phosphate, chlorine content, etc.

Some known apparatus of this nature based upon a colorimetric principle have utilized reagents in the nature of solid rods which act as indicators, buffers, etc., and which solid rods are openly introduced into a mixing vessel wherein they are contacted by the fluids that are to be tested. Color of the fluid contacted by the solid reagent rods is affected by the reagent which is washed off or dissolved into the fluid, and this results in a color change depending upon the chemical constituent in the fluid being sought, and which color is brought about by a chemical reaction between the chemical content and the reagent. In some intances the amount of color change is measured colorimetrieally to give a quantitative value of content of the chemical being sought. The composition of the reagent rod used is varied, dependent upon requirements for colorimetrieally indicating specified chemicals in the fluid. Additionally, the reagent rods can contain additional substances in the nature of buffers etc. Such reactions, and chemical reagents required, to bring about color changes for indicating chemical components carried in the fluid are well-known.

Apparatus heretofore known, have for the most part included open vessels or chambers, and used agitators for insuring a proper mixing, of reagent in the fluids.

The present invention, while broadly related to such previously known apparatus, includes structure whereby the reagent reaction rod is physically separated from a mixing chamber or vessel by means of a fluid pervious diaphragm in such a manner that reagent from the reagent rod is mixed with the liquid by diffusion through the diaphragm, thus providing· improved results by preventing contamination of the reagent rod, or accumulation of crystals or the like on the rod which might otherwise alter its effective transmission of the reagent to the fluid. Additionally, the present invention, due to the arrangement of the reagent rod out of direct contact or immersion, in the fluid, insures an equal reactance face area of the rod with respect to the fluid through the diaphragm. .

Additionally, the present invention teaches apparatus for colorimetrieally testing fluids continuously, and which has outstanding reliability in action due to lack of moving parts and valves or the like, the entire system and apparatus functioning automatically, continuously and by gravitational flow of the fluid, which flow can be regulated as desired.

Other features and advantages of the present invention will be more readily apparent from the following detailed description of an embodiment thereof when ³⁰ ao

65.

taken together with the accompanying drawing in which the single figure of the drawing schematically depicts an embodiment of the invention.

Referring now in detail to the drawings, the apparatus includes a housing generally designated 10, and which can consist of a block of desired material in which various chambers and passages are provided. An inlet fitting 12 for fluid to be tested is connected into housing 10 and opens into an inlet fluid channel 14, which discharges the sample fluid into an overflow chamber 16 adapted for maintaining a constant volume or head of fluid. Excess fluid flows over a weir lip 18 or the like, as indicated by. arrow 20. The overflow passes into a fluid discharge channel 22 and drains out of outlet opening 24. A mixing chamber 26 is provided in housing -10 and is interconnected with the overflow chamber 16 by channel 28. As shown in the drawing, the overflow chamber 16 is situated in a plenum chamber 30 in open communication with the atmosphere by means of vent pipe 32.

The mixing chamber 26 extends upwardly through the top wall of housing 10, terminating in an opening 34. A tubular casing or the like 36, preferably open at both ends, extends downwardly into the upper portion of mixing chamber 26, through opening 34, and is positioned therein by means of flange 38 coacting with the top· of housing 10 around opening 34. The lower end of tubular casing; 36 has a liquid pervious diaphragm 40 secured in the open end thereof. A stick or rod of solid reagent 42 is slidably confined within tubular housing 36, with its lower end resting on and supported by the diaphragm 40. A weight 44 rests On the upper end of reagent rod 42 and maintains the lower end thereof in contact with the diaphragm 40 at all times. In operation, as liquid passes into and through mixing chamber 26, the lower end of reagent rod 42, being in contact with the liquid pervious diaphragm 40, will mix the reagent into the liquid by diffusion through the diaphragm.

In order to insure a proper and thorough mixing of the sample fluid with the reagent in the rod, agitation means are provided including a permanent magnet reagent mixing bar or rod 46, enclosed in glass or plastic, and which is freely movable in all directions in mixing chamber 26. An air gap transformer 48 or the like is disposed externally of mixing chamber 26 and has a big leakage field. When the transformer is actuated by means of A.C. current of for example 50 to 60 cycles, the transformer will cause movement and rotation of the mixing bar 46, which therefore constitutes means for mixing the liquid and reagent which has diffused through the diaphragm 40.

The so mixed fluid and reagent upon reaction with the chemical provides a color change in the sample fluid dependent upon the chemical constituent being sought, and the nature of the reagent in· the reagent rod, in a known manner to provide a colorimetrieally suitable test sample. The so mixed fluid passes from the mixing chamber 26 through channel 50 into an optical measuring chamber 52 through inlet conduit 54 which, is open at its upper end 56 to the atmosphere. The fluid then passes from the measuring chamber 52 through a discharge conduit 58 which acts as an overflow pipe in overflow chamber 60. Fluid flowing out of conduit 58 into chamber 60 passes into discharge channel 62 flowing to outlet opening 24. Measuring chamber 52 is connected to the atmosphere by means of the open upper end 56 of conduit 54.

The liquid levels in overflow chamber 16 and overflow chamber 36 are fixed by the respective positions of weir 18 and the outlet of conduit 58. This provides a constant water level or fluid level in mixing chamber 26. If desired, the various overflows can be made adjustable

2,995,425 purpose likewise being well-known, a detailed description thereof is not considered necessary.

The apparatus of the present invention has been only schematically shown in the drawings for sake of simplicity and clarity. It is felt that the basic concepts and structure, however, are clearly understandable therefrom. Manifestly many minor changes in details of construction and arrangement can be effected within the scope and spirit of the invention without departing therefrom, as limited solely by the appended claims.