US3098718A

US3098718A - Concentration apparatus for quantitative analysis of a substance in a liquid

Info

Publication number: US3098718A
Application number: US838579A
Authority: US
Inventors: Ferrari Andres
Original assignee: Technicon Instruments Corp
Current assignee: Bayer Corp
Priority date: 1959-09-08
Filing date: 1959-09-08
Publication date: 1963-07-23
Anticipated expiration: 1980-07-23

Description

July 23, 1963 A. FERRARI 3,093,718

CONCENTRATION APPARATUS FOR QUANTITATIVE ANALYSIS OF A SUBSTANCE IN A LIQUID Filed Sept. 8, 1959 IN V EN TOR A voges FE A Arr-owns) rates atent Ofificc Patented July 23, 1963 CONCENTRATION APPARATUS FOR QUANTITA- TIVE ANALYSES OF A SUBSTANCE IN A LIQUID Andres Ferrari, Scarsdale, N.Y., assignor to Technicon Instruments Corporation, Chauncey, N.Y., a corporation of New York Filed Sept. 8, 1959, Scr. No. 838,579 6 Claims. (Cl. 23-253) This invention relates to a liquid concentration and treatment method and apparatus. for quantitative analysis of said liquid in respect to a substance therein.

One object of the invention is to provide apparatus which is well adapted for use in a continuou analysis system for flash-heating a flowing stream of a liquid for partial evaporation thereof, in order to increase the concentration of a substance therein, especially in the case of liquids in which the substance is present in minute or only trace quantities, with concurrent with-dr-awalof the concentrated liquid and treatment thereof for colorimetric examination.

In accordance with another object of the invention, the apparatus may be provided with means to introduce a reagent into the liquid under investigation with respect to a constituent thereof whereby when the liquid containing said reagent is heated, the constituent which may be present in a normally insoluble form is. rendered soluble in the liquid and its concentration therein is increased by liquid evaporation. For example, in theanalysis of boiler feed water supplied to steam boilers from condensers in power plants or boiler rooms, such water containing, in addition to water-soluble iron, highly oxidized iron which is considered insoluble, would be rendered totally soluble by the addition of sulfuric acid to said liquid andthe heating of the liquid would greatly increase the concentration of the iron whereby to facilitate analysis.

A further object is the provision of a continuous analysis system or method, as distinguished from a batch or discontinuous method of analysis, for performing quantitative analyses of a liquid in respect to substances which are present therein in trace or very small quantities.

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

In the drawings:

FIG. 1 is a schematic view illustrative of the apparatus and method of the present invention;

FIG. 2 is a view partly in elevation and partly in section and on a larger scale of part of the apparatus; and

FIG. 3 is. a sectional view, on a larger scale, on the line 3-3 of FIG. 2.

Referring to the drawings in detail, the apparatus of the present invention comprises a glass flask 1t mounted for rotation about its longitudinalaxis and disposed in a downwardly inclined position for rotation in said position with an electrically heated oven 12. As illustrated in FIG. 2, oven 12 has a stationary lower section 14 and an upper movable section 16 which is hinged to the lower section 14 by the hinge indicated at 18 so that said upper section can be moved to retracted position to permitthe insertion and removal of flask 10. The electric resistance heating elements on said sections are indicated at 20, and it will be understood that the electric heater constituted by said resistance elements surrounds the flask and also confronts the bottom thereof as illustrated in FIG. 2. Sections 14 and 16 of the electrically heated oven 12 are provided with suitable heat insulation as indicated at 22.

The flask lit is mounted for rotation by a hollow rotary shaft 24 which has an end portion 26 which is firictionally engaged by the mouth 28 of the flask, interiorly of the latter, for removably supporting the flask and providing a fluid-tight seal with the mouth of the flask. Hollow shaft 24 is removably secured by-a chuck St) to the flange 31 of a rotary gear 32 which is journaled in a bearing 33 at the upper end of post 34. An electric motor 35 which may also be supported on said post a-ctu-ates shaft 24, the driving connection between the motor and said shaft being here shown as comprising the bevel gear 36 which meshes with the bevel gear 32. It will be understood that flask 10 may be rotated at a suitable speed, according to the gear ratio of

gears

32 and 36 and also by the provision, ifdesired, of speed reducing gearing (not shown), drivingly connecting the shaft of motor 35 to shaft 24 in any suitable way.

A plurality of fluid passages extend through shaft 24 into flask 10 These passages are preferably constituted by a plurality of

glass tubes

38, 40 and 42. Tube 38 provides a tubular passage for the introduction of the liquid, which is to be concentrated, into the flask at an upper part thereof, as clearly shown in FIGS. 1 and 2. More particularly, the liquid inlet for the flask is provided by the inner end or outlet end 44 of said tube, so that the liquid supplied through tube 38 flows downwardly on the inner side of the flask to the bottom thereof. Since the flask is being rotated and is in heated condition while the liquid is introduced into the flask, the liquid comes in contact with successive portions of the flask peripherally thereof, as well as longitudinally thereof in the form of a film-like coating on the inner surface of the flask so that rapid evaporation of some of the liquid occurs with concomitant concentration of the liquid during the flow of the liquid to the bottom of the flask. Tube 40 provides means for withdrawing the concentrated liquid from the flask and for this purpose the inner end portion 46 of said tube is positioned, as illustrated in FIG. 2, so that it is immersed in the pool of liquid which collects at the bottom of the flask. Tube 42 is provided for withdrawing vapors or fumes from theflask'formed as a result of theheating or flash evaporation of some of the liquid which is admitted through tube 38. Tube 42 is connected to an aspirator 43 of a well known type which is operated by a stream of water, which flows through tube 45, for withdrawing the fumes through said tube. The water is also effective to dilute and cool the fumes so that the fluids may be exhausted to waste through the outlet 47. The rate of withdrawal of the vapors or fumes may be adjusted to prevent the accumulation of excessive pressure within the flask.

The apparatus of the present invention includes means for transmitting the liquid through tube 38 for concentration in flask 10, as Well as means for withdrawing from the flask the concentrated liquid, concurrently with the introduction into the flask of the liquid which is to be concentrated therein. For these purposes there is provided a proportioning pump 52 of any suitable construction for transmitting liquids or fluids into the flask and withdrawing them from the flask at predetermined rates of flow. The proportioning pump is preferably of the type described in U.S. Patent No. 2,893,324, issued to the assignee of the present application. Briefly described, said pump comprises a plurality of resiliently compressible tubes which are mounted on a platen in laterally spaced relation and which are engaged simultaneously by a plurality of pressure rollers which are moved progressively along the lengths of the tubes for pumping the liquids or fluids therethrough. As the pnoportioning pump does not'in itself constitute a part of the present invention, further description and illustration thereof are unnecessary.

The apparatus of the present invention, as thus far described, may be emploved solely for the purpose of concentrating a liquid, for example, when the liquid contains a very small quantity of a substance by reason of which quantitative analysis of the liquid in respect to said substance in the liquid is ordinarily extremely difl'icult or impossible, especially in continuous analysis or monitoring systems. More particularly, in power plant operations, for example, the analysis of boiler feed water in respect to the iron or copper content thereof, requires the employment of trace analysis techniques, such as the use of long flow cell colorimeters and other complicated devices and procedures because of the low concentration of iron or copper, as the case may be, in the feed water. Accordingly, by treating the boiler feed water fior increasing the concentration of the iron or copper concurrently with the performance of the analysis or monitoring operation, the important advantage is obtained by reason of the fact that it is possible to employ a continuous analysis system without requiring the use of complicated trace analysis techniques and devices. This will be more clearly evident from the following description of a method of continuous analysis of boiler feed water for the quantitative determination of iron therein.

With further reference to FIG. 1, a stream of the boiler feed water is transmitted by the pump tube 54 to a helical glass mixing coil 56 simultaneously with the transmission to said mixing coil of sulfuric acid (50% concentration) by the pump tube 58. When the water containing the sulfuric acid is heated to a high temperature in flask any iron which may be present in the water and is normally insoluble therein is rendered soluble. The acid treated water passes from the mixing coil 56 to the tube 38 and is introduced by the latter into the heated revolving flask, and as a result any insoluble iron present in the water is dissolved therein and the total iron concentration is increased. The concentrated liquid is withdrawn through the flask 10' through the tube 40 and is transmitted through the mixing and cooling coil 60 by the pump tube 62 where it is mixed with potassium thiocy-anate (40% concentration) introduced into the mixing coil by the pump tube 64. Air or other inert gas is preferably introduced into the liquid stream prior to the flow thereof into the mixing coil, through the pump tube 66, whereby the stream of liquid is divided by said air or other inert gas into flowing segments of liquid separated from each other by intervening segments of the gas, one of the purposes of segmentizing the stream being to provide a cleansing action on the tubular pas sages. The pump tube 62 by which the liquid stream is withdrawn from flask 10 and transmitted through the mixing coil together with the potassium thi-ocyanate is connected to a tube 68 for transmitting the liquid through the flow cell (not shown) of a colorimeter 7 0 which controls the operation of a recorder 72 in a well known manner. It will be understood that the potassium thiocyanite constitutes a color reagent for treating the concentrated liquid stream for colorimetric examination in respect to the total iron content of the boiler feed water concurrently with the concentration operation.

An overflow tube 74, which is made of glass, is provided to limit the quantity of liquid which may collect in flask 10, the inlet end 76 of this overflow tube being above the inlet end of tube 46. Said overflow tube 74 is connected to the aspirator 43 for the removal of excess liquid from the flask, and it will be noted that the stream of water which flows through the aspirator is effective to cool and dilute the hot liquid.

As an illustrative but not limitative example of the rates of flow of the above-mentioned fluids pursuant to the operation of the proportioning pump 52 concurrently with the continuous concentration described above, it may be noted that the boiler feed water under analysis is transmitted by pump tube 54 at the rate of 11.7 mls. per minute, the sulfuric acid is transmitted through pump tube 58 at the rate of 1.2 mls. per minute, the potassium thiocyanate is transmitted through pump tube 64 at the rate of 2.0 mls. per minute, and the air is transmitted through pump tube 66 at the rate of 0.8 ml. per minute. The liquid introduced into the flask is heated to a temperature of about 350 C. to 400 C.

While I have shown and described the preferred embodiment of my 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 par-ts and in the specific manner of practicing the invention may be made without departing from the underlying idea orprinciples of this invention within the scope of the appended claims.

What I claim is:

l. Liquid-treatment apparatus, comprising a flask mounted for rotation about its longitudinal axis, said flask being disposed in a downwardly inclined position during its rotation, means =for rotating said flask in said position about said axis, means for heating said flask during said rotation thereof, and stationary conduit means extending into said flask and providing a plurality of fluid passages in communication with the interior of the flask, said flask being rotated about said conduit means by said flask rotating means, one of said passages terminating in a liquid inlet positioned above the bottom of the flask adjacent the side thereof so that liquid admitted through said inlet flows down and around on the inner heated side of the flask during the rotation of said flask in contact with successive peripheral portions or said inner side to form a liquid film thereon for effecting a rapid heating and partial evaporation of the liquid as it flows to the bottom of the flask, another of said passages terminating nearer the bottom of the flask than said inlet passage and constituting an outlet passage for the heated liquid while the flask rotates, and another of said passages having an inlet opening above the termination of said last mentioned passage and providing an overflow passage for the heated liquid to limit the quantity of concentrated liquid at the bottom of the flask while the flask rotates. e a

2. Liquidatreatment apparatus, comprising a flask mounted for rotation about its longitudinal axis, said,

flask being disposed in a downwardly inclined position during its rotation, means for rotating said flask in said position about said axis, means for heating said flask during said rotation thereof, aid a plurality of stationary conduits extending into said flask for providing a plurality cf fluid passages in communication with the interior of the flask, said flask being rotated about said conduit means by said flask rotating means, one of said passages terminating in a liquid inlet positioned above the bottom of the flask adjacent the side thereof so that liquid admitted through said inlet flows down and around on the inner heated side of the flask during the rotation of said flask in contact with successive peripheral portions of said inner side to form a liquid filmrthereon for effecting a rapid heating and partial evaporation of the liquid as it flows to the bottom of the flask, another of said p'a-ssages terminating nearer the bottom of the flask than said inlet passage and constituting an outlet pass-age for the heated liquid which the flask rotates, another of said passages having an inlet opening above the lower end of said last mentioned passage and providing an overflow passage for the heated liquid to limit the quantity of heated liquid at the bottom of the flask, one of said conduits providing a passage for withdrawing from said flask vapors formed during said heating of the liquid.

3. Liquidtreatment apparatus, comprisifig a flask having an open top, an inclined rotary hollow member inserted in said open top and engaged therewith for mounting said flask for rotation about its longitudinal axis in a downwardly inclined position, means for rotating said hollow member and thereby rotating said flask in said position about said axis, means for heating said flask during said rotation thereof, and a plurality of stationary conduits disposed in said rotary hollow member and extending into said flask through said open top thereof to provide a plurality of stationary fluid passages in communication with the interior f said flask during the rotation thereof, one of said conduits terminating in a liquid inlet positioned above the bottom of said flask adjacent the side thereof so that liquid admitted through said inlet during the rotation of said flask flows down and around on the inner heated side of the flask during the rotation of said flask in contact with successive peripheral portions of said inner side thereof for effecting a rapid heating and partial evaporation of the liquid as it flows to the bottom of the flask, and another of said conduits terminating nearer the bottom of said flask than said liquid inlet and constituting an outlet passage for the heated liquid.

4. Liquid-treatment apparatus, comprising a flask having an open top, an inclined rotary hollow member inserted in said open top and engaged therewith for mounting said flask for rotation about its longitudinal axis in a downwardly inclined position, means for rotating said hollow member and thereby rotating said flask in said position about said axis, means for heating said flask during said rotation thereof, and a plurality of stationary conduits disposed in said rotary hollow member and extending into said. flask through said open end thereof to provide -a plurality of stationary fluid passages in communication with the interior of said flask while the flask rotates, one of said conduits terminating in a liquid inlet positioned above the bottom of said flask adjacent the side thereof so that liquid admitted through said inlet flows down and around on the inner heated side of the flask during the rotation of said flask in contact with successive peripheral portions of said inner side thereof for effecting a rapid heating and partial evaporation of the liquid as it flows to the bottom of the flask, another of said conduits terminating nearer the bottom of said flask than said liquid inlet and constituting an outlet passage for the heated liquid, and another of said conduits having an inlet opening above the lower end of said last mentioned conduit for providing an overflow passage for the heated liquid to limit the quantity of liquid in said flask.

5. Apparatus for treating a liquid for quantitative analysis in respect to a substance present therein in a small quantity, comprising a vessel mounted for rotation about its longitudinal axis and having a downwardly inclined inner surface means for rotating said vessel about said axis, means for heating said vessel while it is being rotated about said axis, an inlet tube for said liquid having its outlet end positioned above the bottom of said vessel adjacent said inner turfaceso that liquid admitted through said inlet end flows down and 'around said inner surface during the rotation of said vessel to form a liquid film thereon for effecting a rapid evaporation of a portion of said liquid as it flows to the bottom of said vessel, an outlet tube having its inlet end adjacent the bottom of said vessel [for withdrawing the heated liquid therefrom in the form of a stream, said tubes being stationary and said vessel being rotated around the axes of said tubes by said rotating means while the flask is being heated and means in liquid flow communication with said outlet tube for treating said withdrawn liquid stream for analysis concurrently with said evaporation operation and rotation of said vessel.

6. Apparatus for treating a liquid for quantitative analysis in respect to a substance present therein in a small quantity, comprising a vessel mounted for rotation about its longitudinal axis and having a downwardly inclined inner surface means for rotating said vessel about said axis, means for heating said vessel during its said rotation and thereby heating said inner surface, an inlet tube for said liquid having its outlet end positioned above the bottom of said vessel adjacent said inner surface so that liquid admitted through said inlet end flows down and around said heated inner surface during the rotation of said vessel to form -a liquid film thereon for effecting a rapid heating and partial evaporation of the liquid as it flow-s to the bottom of said vessel, an outlet tube having its inlet end adjacent the bottom of said vessel for withdrawing the concentrated liquid therefrom in the form of a stream, said tubes being stationary and said vessel being rotated around the axes of said tubes by said rotating means while the flask is being heated, means in liquid flow communication with said outlet tube for treating said withdrawn liquid stream for analysis concurrently with said evaporation operation and rotation of said vessel, and a stationary tube extending into said vessel to a point above end of said outlet tube for Withdrawing vapors formed during the heating of said vessel.

References Cited in the file of this patent UNITED STATES PATENTS 1,086,432 Zinkeiser et a1. July 14, 1911 1,231,247 Freeman June 26, 1917 2,686,754 Monod Aug. 17, 1954 2,879,141 Skeggs Mar. 24, 1959 2,899,280 Whitehead Aug. 11, 1959 2,941,501 Bell June 21, 1960 OTHER REFERENCES Analytical Chemistry, volume 14, Feb. 15, 1942, page 166, Determination of Solubilities of Gases at High Temperatures and High Pressures by the Rotating Born by Ispatieff et a1.

Claims

5. APPARATUS FOR TREATING A LIQUID FOR QUANTITATIVE ANALYSIS IN RESPECT TO A SUBSTANCE PRESENT THEREIN IN A SMALL QUANTITY, COMPRISING A VESSEL MOUNTED FOR ROTATION ABOUT ITS LONGITUDINAL AXIS AND HAVING A DOWNWARDLY INCLINED INNER SURFACE MEANS FOR ROTATION SAID VESSEL ABOUT SAID AXIS, MEANS FOR HEATING SAID VESSEL WHILE IT IS BEING ROTATED ABOUT SaID AXID, AN INLET TUBE FOR SAID LIQUID HAVING ITS OUTLET END POSITIONED ABOVE THE BOTTOM OF SAID VESSEL ADJACENT SAID INNER TURFACE SO THE LIQUID ADMITTED THROUGH SAID INLET END FLOWS DOWN AND AROUND SAID INNER SURFACE DURING THE ROTATION OF SAID VESSEL TO FORM A LIQUID FILM THEREON FOR EFFECTING A RAPID EVAPORATION OF A PORTION OF SAID LIQUID AS IT FLOWS TO THE BOTTOM OF SAID VESSEL, AN OUTLET TUBE HAVING ITS INLET END ADJACENT THE BOTTOM OF SAID VESSEL FOR WITHDRAWING THE HEATED LIQUID THEREFROM IN THE FORM OF A STREAM, SAID TUBES BEING STATIONARY AND SAID VESSEL BEING ROTATED AROUND THE AXES OF SAID TUBES BY SAID ROTATING MEANS WHILE THE FLASK IS BEING HEATED AND MEANS IN LIQUID FLOW COMMUNICATION WITH SAID OUTLET TUBE FOR TREATING SAID WITHDRAWN LIQUID STREAM FOR ANALYSIS CONCURRENTLY WITH SAID EVAPORATION OPERATION AND ROTAION SAID VESSEL.