US3740157A - Flow cuvette - Google Patents

Flow cuvette Download PDF

Info

Publication number
US3740157A
US3740157A US00159866A US3740157DA US3740157A US 3740157 A US3740157 A US 3740157A US 00159866 A US00159866 A US 00159866A US 3740157D A US3740157D A US 3740157DA US 3740157 A US3740157 A US 3740157A
Authority
US
United States
Prior art keywords
conduit means
cuvette
funnel
measuring chamber
liquid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00159866A
Other languages
English (en)
Inventor
V Kasparek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US3740157A publication Critical patent/US3740157A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G01N21/03—Cuvette constructions
    • G01N21/05—Flow-through cuvettes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01—Arrangements or apparatus for facilitating the optical investigation
    • G01N21/03—Cuvette constructions
    • G01N21/05—Flow-through cuvettes
    • G01N2021/054—Bubble trap; Debubbling

Definitions

  • a funnel is attached to the end of the drain tube to aid in the introduction of the sample.
  • a UNITED STATES PATENTS means can be included in the funnel to prevent eddying Schubart or vortexing of the ample and thus prevent en 356/246 trainment of air bubbles in the sample.
  • the present invention relates to a flow cuvette which is used for retaining and holding samples for photometric, fluorometric, turbidimetric, and nephelometric measurements.
  • the flow cuvette provides a transparent measuring chamber for the reception of the liquid to be investigated.
  • Prior art flow cuvettes of this type have to be either connected to a pump, such as an air pump, or provided with a series of shutoff valves for the purpose of filling and emptying the samples from the cuvette. Operation of these cuvettes, therefore, is fairly cumbersome; and for this reason, the earlier models consisting simply of a glass or quartz chamber are usually still preferred. These devices were formed in various shapes, such as a hollow cylinder or a hollow prism. These simple cuvettes, however, have the disadvantage that for emptying and refilling they must be removed from the photometric-type instrument. Thus, each time a sample is changed, the cuvette must be removed from the instrument and replaced.
  • the present invention is intended to provide a flow cuvette which is simple to operate and which does not have to be removed from the photometric-type equipment when a change of sample is to be made.
  • Another object of this invention is that the sample of the liquid present in the flow cuvette automatically is removed and drained away by simply feeding in the next sample. With this apparatus, an ai bubble divides the two samples, thus, preventing the samples from flowing together and becoming mixed.
  • Another object consists in the provision of a flow cuvette wherein the liquid to be investigated can flow into the sample chamber without the introduction of air bubbles even though the successive samples of liquid are separated by an air bubble.
  • the flow cuvette of the present invention is characterized in that the sample or measuring chamber is attached at the bottom to an upwardly directed U-shaped feed tube and at the top to a downwardly directed U- shaped drain tube.
  • the feed tube is designed so that it extends at least above the upper end portion of the drain tube.
  • the lower end of the drain tube is positioned so that it does not extend beyond the lower or bottom end portion of the feed tube.
  • a funnel is provided at the upper end of the feed tube, thus, facilitating the introduction of the liquid sample to the device.
  • Vortexing or eddying in a funnel of this nature can cause the introduction of air bubbles to the liquid sample which is being introduced and, thus, render the sample unsatisfactory for the photometric-type process.
  • the funnel can be designed to prevent this vortexing by various means such as designing the inside surface of the funnel with an elliptical cross-section, providing longitudinal ribs on the inside surface of the funnel, or providing X- shaped cross ribs in the funnel. These ribs can be permanently attached or designed to be easily removed, as desired.
  • the drain tube In certain types of measurements, such as those car ried out with a fluorometric or a nephelometric instrument, it is convenient for the drain tube to project at an angle of about from the common plane which encompasses both the feed tube and the measuring chamber which is necessary in this type of instrument.
  • FIG. 1 is a side elevation view of the flow cuvette of the present invention
  • FIG. 2 is a sectional view of the funnel portion taken on the line 2-2 of FIG. 1;
  • FIG. 3 is a side elevation of a second embodiment of this invention.
  • FIG. 4 is a top plan view of the flow cuvette shown in FIG. 3; l
  • FIG. 5 shows an enlarged plan view of an embodiment of the feed funnel
  • FIG. 6 shows an enlarged detail view of the attachment of the rib to the inside surface of the feedfunnel of FIG. 5.
  • the flow cuvette of the present invention is composed of a feed tube 1 which is provided in this embodiment with a feed funnel 2
  • the funnel 2 as can be seen in FIG. 2, has an elliptical cross-section 3 constituting a vortex preventing means so that eddying or vortexing of the inflowing; liquid will be presented. Vortexing in a funnel arrangement such as this allows the entrainment of air bubbles in the inner central portion of the liquid flow.
  • This: type of funnel crosssection is utilized to prevent such vortexing and consequently this air entrainment. [t has been found that a liquid which contains air bubbles is not satisfactory for carrying out photometric-type measurements.
  • the feed tube 1 is formed at its end'in a U-shape or bend 4 which opens upwardly into a sample or measuring chamber 5.
  • the measuring chamber 5 can have a somewhat larger diameter eross-section than that of the feed tube 1
  • This measuring chamber 5 is connected at its top end to a drain tube 6 which also has a U-shape or 180 bend 7, and thereafter is directed downwardly.
  • the feed tube 1 extends at least above the upper edge 7a of the drain tube bend; and in addition, the drain tube 6 is open at its lower end a nd terminates at a point which is above the lower edge Ia of the bend 4 of the feed tube 1. It has been found that the best results are obtained when the outlet orifice of the drain tube 6 is positioned at about'the level of the innerradius of the bottom end portion or lower bend 4.
  • the dimension designated as a in FIG. 1 is the distance the drain tube 6 terminates above the lower edge 1a of the bend 4.
  • m is the mass of a drop of liquid detaching from the drain tube
  • F is the surface tension of the liquid.
  • the maximum permissible radius r is an amount effective to establish a hydrostatic equilibrium so that the liquid is maintained within the measuring chamber and the open ended drain tube 6.
  • a second sample is poured into the funnel 2, and this sample, in turn, pushes out the previous sample from the cuvette. Mixing of the two samples is prevented by the entrapped air bubble which forms between the two samples of liquid during the introduction of the second sample. If an excess of the second sample is introduced, this excess will wash away any remainder of the previous sample which has adhered to'the inner walls of the cuvette. Thus, any contamination of the first portion of the second sample can be flushed away with a minimum of liquid loss.
  • the drain tube in a direction of approximately 90 from the common plane of the measurement chamber and the feed tube 1. This permits different positioning and access of the measurement chamber with respect to the measuring instrument.
  • the feed tube 1 can be of a straight section as shown in FIG. 3 or of an offset arrangement as shown in FIG. 1. With the offset arrangement, the funnel 2 can be positioned over the measuring chamber 5 and, thus, provide a more compact unit.
  • the cuvette includes a feed tube 8 which is joined through the bottom end portion or U-shaped bend 9 to a measuring or sample chamber 10.
  • the measuring chamber 10 has the same diameter as the feed tube 8. It is to be understood that the measuring chamber 10 can be of any diameter that is desired. Usually this diameter is dictated by the type of instrument that is to be used.
  • the upper end of the measuring chamber 10 then merges with a second U-shaped bend 11 which then extends into a downwardly directed drain tube 12. Again, the open end of this drain tube 12 is positioned above the lower bottom portion of the feed tube 8.
  • the drain tube 12 does not lie in a common plane of the measuring chamber 10 and the feed tube 8, but is repositioned approximately 90 thereto.
  • the desired access to the measuring chamber 10, as explained above, can be obtained.
  • the feed tube 8 has mounted at its upper end a feed funnel 13 whose inside surfaces define the shape of an inverted frustum 14.
  • Three guide ribs 15, each displaced l, are positioned on the inside surface 14 of the funnel and project radially inward from the inside surface of the funnel 13. These ribs provide an antivorlexing means to prevent the eddy or whirlpool effect during the introduction of the liquid sample to be investigated.
  • the radial dimension of the guide ribs 15 may only be a portion of the radius or can extend the entire radius of the funnel, as shown in FIG. 5.
  • each guide rib 15 is provided with a retaining bead 15a which is intended to be mated with an appropriate groove 15b formed in the side wall of the funnel.
  • the guide rib 15 can be slid into the guide groove 15b and, thus, form an easy means of attachment.
  • the guide ribs 15 are therefore easily installed and removed and may be used in any number of combinations desired based primarily according to the viscosity of liquid being investigated. It should be understood that these guide ribs could be permanently or integrally molded into the surface of the funnel and that any number of guide ribs could be integrally formed. As another possibility, all the guide ribs could be formed in one piece which is then simply inserted into the funnel when required. It is to be further understood that the funnel itself can be eliminated, if desired, and any form of device effective to aid in the introduction of the sample and to prevent vortices in the inflowing liquid can be used.
  • the cuvette described herein is preferably made from glass, such as quartz glass. Other materials may, however, be used for the manufacture of the cuvette provided they exhibit the ray transparency required of the photometric type equipment and are stable with respect to the liquid to be investigated. Plastics such as Plexiglass may also be used. If desired, it is possible to make only the measuring chamber 5 or 10 of a raytransparent material and to use another material for the remaining parts of the cuvette. The choice of materials used will be governed mainly by the liquid to be investigated and the radiation, for example, visible light, infrared, or ultraviolet rays, used by the analyzing instrument.
  • a flow cuvette for retaining a liquid sample for photometric-type investigations comprising:
  • a downwardly directed outlet conduit means with one end connected to the top of said measuring chamber and there being an open outlet at the op posite end thereof;
  • the maximum permissible radius of the drain conduit means being an amount effective to establish a hydrostatic equilibrium so that liquid may be maintained within the measuring chamber and the open ended drain conduit means.
  • a flow cuvette as defined in claim 3 wherein the vortex preventing means comprises an elliptical cross section configuration on the linear surface of the funnel means.
  • a flow cuvette as claimed in claim 3 wherein the vortex preventing means comprises one or more ribs located on the inner surface of said funnel means and which extend radially inwardly towards the center axis of the funnel means.
  • each guide rib includes a bead and the inner surface of the funnel means includes a longitudinal groove which mates with said bead of the rib, said bead thereby constitutes an attachment means for said rib when it is located in said groove.
  • a flow cuvette for retaining a liquid sample to be measured comprising:
  • a downwardly directed, tubular drain conduit means having an upper end portion connected to the top of said measuring chamber and a lower end thereof being open,
  • said feed conduit means extending upwardly at least to the level of the upper edge of said upper end portion
  • drain conduit means extending downwardly a distance which does not extend beyond the level of the lower most portion of the feed conduit means
  • the maximum permissible radius of the tubular drain conduit means being an amount effective to establish a hydrostatic equilibrium so that liquid may be maintained within the measuring chamber and the open ended tubular drain conduit means.
  • a cuvette as defined in claim 12 wherein the maximum permissible radius of the drain conduit means is defined by the formula:
  • r is. the maximum permissible radius of the drain conduit means;
  • m is the mass ofa drop of the liquid detaching from the drain conduit means;
  • a cuvette as defined in claim 15 wherein the vortex preventing means comprises an elliptical cross-section configuration on the inner surface of I the funnel means.
  • a cuvette as defined in claim 15 wherein I the vortex preventing means comprises one or more ribs located on the inner surface of said funnel means and which extend radially toward the center axis of the funnel means.

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Optical Measuring Cells (AREA)
US00159866A 1970-07-06 1971-07-06 Flow cuvette Expired - Lifetime US3740157A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1022170A CH515502A (de) 1970-07-06 1970-07-06 Durchflussküvette

Publications (1)

Publication Number Publication Date
US3740157A true US3740157A (en) 1973-06-19

Family

ID=4360753

Family Applications (1)

Application Number Title Priority Date Filing Date
US00159866A Expired - Lifetime US3740157A (en) 1970-07-06 1971-07-06 Flow cuvette

Country Status (6)

Country Link
US (1) US3740157A (de)
CH (1) CH515502A (de)
DE (1) DE2132308A1 (de)
FR (1) FR2100249A5 (de)
GB (1) GB1361044A (de)
SE (1) SE375615B (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4312591A (en) * 1978-02-07 1982-01-26 Bodenseewerk Perkin-Elmer & Co. Gmbh Apparatus for automatically transporting liquid samples to an analyzer
US4567021A (en) * 1981-10-19 1986-01-28 Olympus Optical Company Limited U-Shaped reaction tube made of elastic material
FR2719902A1 (fr) * 1994-05-11 1995-11-17 Pasteur Sanofi Diagnostics Système d'analyse optique d'un échantillon de mélange réactionnel.
CN105181593A (zh) * 2015-10-14 2015-12-23 厦门大学 一种无气泡干扰流通池，流动分析-光学检测装置及用途
CN111751283A (zh) * 2020-06-23 2020-10-09 苏州国溯科技有限公司 一种流通比色池及进样和清洗的方法
CN113671098A (zh) * 2020-05-13 2021-11-19 上海伍丰科学仪器有限公司 一种用于液相色谱仪荧光检测器的流通池部件

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2467599A (en) * 1945-01-23 1949-04-19 Frederick C Schubart Colorimetric vessel
US3236602A (en) * 1962-05-03 1966-02-22 Technicon Instr Colorimeter flow cell and holder therefor
US3580686A (en) * 1969-03-17 1971-05-25 Coulter Electronics Vessel having intersample anticontamination construction

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2467599A (en) * 1945-01-23 1949-04-19 Frederick C Schubart Colorimetric vessel
US3236602A (en) * 1962-05-03 1966-02-22 Technicon Instr Colorimeter flow cell and holder therefor
US3580686A (en) * 1969-03-17 1971-05-25 Coulter Electronics Vessel having intersample anticontamination construction

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4312591A (en) * 1978-02-07 1982-01-26 Bodenseewerk Perkin-Elmer & Co. Gmbh Apparatus for automatically transporting liquid samples to an analyzer
US4567021A (en) * 1981-10-19 1986-01-28 Olympus Optical Company Limited U-Shaped reaction tube made of elastic material
FR2719902A1 (fr) * 1994-05-11 1995-11-17 Pasteur Sanofi Diagnostics Système d'analyse optique d'un échantillon de mélange réactionnel.
EP0683387A1 (de) * 1994-05-11 1995-11-22 Pasteur Sanofi Diagnostics Einrichtung zur optischen Analyse einer Probe Reaktionsmischung
CN105181593A (zh) * 2015-10-14 2015-12-23 厦门大学 一种无气泡干扰流通池，流动分析-光学检测装置及用途
CN113671098A (zh) * 2020-05-13 2021-11-19 上海伍丰科学仪器有限公司 一种用于液相色谱仪荧光检测器的流通池部件
CN111751283A (zh) * 2020-06-23 2020-10-09 苏州国溯科技有限公司 一种流通比色池及进样和清洗的方法

Also Published As

Publication number Publication date
SE375615B (de) 1975-04-21
DE2132308A1 (de) 1972-03-09
CH515502A (de) 1971-11-15
FR2100249A5 (de) 1972-03-17
GB1361044A (en) 1974-07-24

Similar Documents

Publication Publication Date Title
US4477186A (en) Photometric cuvette
US4781459A (en) Apparatus for measuring the amount of minute particles contained in liquid
US3838926A (en) Method of continuously determining the absorbance light of a chemical reaction mixture
US4332471A (en) Cuvette with tub-shaped bottom for the optical examination of liquids
US3740157A (en) Flow cuvette
JP2012521007A (ja) キュベット
US3734629A (en) Instrument for determining the optical density of fluids
DE3476121D1 (en) Equipment for the measurement of fluorescence, turbidity, luminescence, or absorption
US4330206A (en) Cuvette for use in optical measurements
US3867042A (en) Cuvette construction
US3702403A (en) Optical testing apparatus comprising means for flowing liquids in free fall condition at constant flow rate
US4681443A (en) Optical detector cell
US3493306A (en) Cell for photometric and/or spectrophotometric measurements
US2003474A (en) Fluid flow meter
US3520517A (en) Through-flow measuring cell for photometers
GB899298A (en) Improvements in or relating to photo-electric colorimeter flow cuvettes
US3582222A (en) Sampling cells
GB1391658A (en) Fluid sample flow cell
US3418061A (en) Flow cell construction with delivery and discharge means
JPH1038796A (ja) 光学的分析用セル
JP5047295B2 (ja) 分光光度計に使用するためのクローズドセル
US3981182A (en) Flow-through capillary viscometer
RU2229113C2 (ru) Модуль для измерения активности жидкости, имеющий средство промывки датчика
SU1578494A1 (ru) Измеритель уровн прозрачной жидкости
RU187228U1 (ru) Фотометрический анализатор жидкости