Patent Publication Number: US-2010126536-A1

Title: Cleaning device and analyzer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of PCT international application Ser. No. PCT/JP2008/063304 filed on Jul. 24, 2008 which designates the United States, incorporated herein by reference, and which claims the benefit of priority from Japanese Patent Application No. 2007-192244, filed on Jul. 24, 2007, incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cleaning device that cleans inside of a vessel and an analyzer that includes the cleaning device. 
     2. Description of the Related Art 
     Conventionally, an analyzer that dispenses a reagent and a specimen into a cuvette and optically detects a reaction of the reagent and the specimen in the cuvette has been known as a device that automatically analyzes a specimen such as blood or body fluid. In such an analyzer, cleaning is performed so that a cuvette can be used repeatedly. Mixed liquid in the cuvette, for which optical measurement has been finished, is sucked and discharged out through a plurality of cleaning nozzles. Cleaning liquid such as detergent or cleaning water is injected and then is sucked away (see Japanese Patent Application Laid-open No. S62-228951). 
     SUMMARY OF THE INVENTION 
     A cleaning device according to an aspect of the invention that cleans inside of a vessel, includes a suction nozzle configured to be inserted into the vessel to suck liquid contained in the vessel; and a supply nozzle configured to be inserted into the vessel to supply cleaning liquid into the vessel, wherein at least one of the suction nozzle and the supply nozzle is formed such that a wall cross-sectional area thereof is larger than an inner-diameter cross-sectional area thereof. 
     An analyzer according to another aspect of the invention that analyzes a liquid specimen contained in a vessel, includes the cleaning device, wherein the cleaning device cleans the vessel, into which the liquid specimen is dispensed in the analyzer. 
     The above and other features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a configuration of an analyzer according to an embodiment of the present invention; 
         FIG. 2  is a schematic diagram explaining a configuration of a cleaning unit shown in  FIG. 1 ; 
         FIG. 3  is a schematic diagram illustrating a cross-sectional shape of each of a supply nozzle and a suction nozzle shown in  FIG. 2 ; 
         FIG. 4  is a schematic diagram illustrating a cross-sectional shape of each of a supply nozzle and a suction nozzle of a conventional technology; 
         FIG. 5  is a schematic diagram illustrating a state in which the supply nozzle and the suction nozzle shown in  FIG. 4  are inserted into the cuvette; 
         FIG. 6  is a schematic diagram illustrating a state in which the supply nozzle and the suction nozzle shown in  FIG. 3  are inserted into the cuvette; 
         FIG. 7  is a schematic diagram illustrating another example of the cross-sectional shape of each of the supply nozzle and the suction nozzle shown in  FIG. 3 ; 
         FIG. 8  is a schematic diagram illustrating a state in which a supply nozzle and a suction nozzle according to the embodiment are inserted into a cuvette; and 
         FIG. 9  is a schematic diagram illustrating a cross-sectional shape of each of the supply nozzle and the suction nozzle shown in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Exemplary embodiments of a cleaning device and an analyzer according to the present invention will be described below with reference to the drawings, taking an analyzer that includes a cleaning device that cleans cuvettes into which liquid specimens such as blood or urine are dispensed as an example. The present invention is not limited to the following embodiments. In the descriptions of the drawings, the same components are denoted with the same reference symbols. 
       FIG. 1  is a schematic diagram illustrating a configuration of an analyzer  1  according to an embodiment of the present invention. As shown in  FIG. 1 , the analyzer  1  of the present embodiment includes a measurement system  2  that dispenses a specimen and a reagent as analysis objects into each of cuvettes  21  and optically measures a reaction that takes place in each of the cuvettes  21  into which the specimen and the reagent are dispensed. The analyzer  1  also includes a controller  3  that controls the entire analyzer  1  including the measurement system  2  and analyzes a result of measurement performed by the measurement system  2 . The analyzer  1  automatically performs biochemical analysis on a plurality of specimens due to cooperation between the above two systems. Each of the cuvettes  21  is a vessel with an extremely small capacity ranging from a few nL (nanoliters) to a few mL (milliliters). The cuvette  21  is made of transparent material capable of transmitting not less than 80% of light contained in analysis light (340 to 800 nm) emitted from a light source of a photometric unit  18 . Examples of the transparent material include glass including heat-resistant glass, and synthetic resin including cyclic olefin and polystyrene. Each of the cuvettes  21  includes a liquid holding portion for holding liquid by a side wall and a bottom wall thereof, and an opening that is formed on an upper portion of the liquid holding portion. 
     The measurement system  2  is now described. The measurement system  2  mainly includes a specimen transfer unit  11 , a specimen dispensing system  12 , a reaction table  13 , a reagent container  14 , a reagent dispensing system  16 , a stirring unit  17 , the photometric unit  18 , and a cleaning unit  19 . 
     The specimen transfer unit  11  includes a plurality of specimen racks  11   b,  each of which carries a plurality of specimen vessels  11   a  each containing a liquid specimen such as blood and is sequentially transferred in a direction indicated by an arrow in the drawing by a not-shown transfer system. A specimen contained in the specimen vessel  11   a  that has been transferred to a predetermined position on the specimen transfer unit  11  is dispensed into the cuvette  21  to be conveyed in an aligned state on the reaction table  13 . 
     The specimen dispensing system  12  has an arm  12   a  that is movable up and down in a vertical direction and rotatable about a vertical line that passes through a base end portion thereof as a central axis. At a tip end portion of the arm  12   a,  a nozzle through which a specimen is sucked in and discharged out is attached. The specimen dispensing system  12  has a not-shown sucking-discharging system that uses a sucking-discharging syringe or a piezo-electric device. The specimen dispensing system  12  sucks in a specimen through the nozzle from the specimen vessel  11   a  that has been transferred to the predetermined position on the specimen transfer unit  11  as described above, and discharges out to dispense the specimen into the cuvette  21  by rotating the arm  12   a  in a clockwise direction in the drawing. 
     The reaction table  13  transfers the cuvette  21  to predetermined positions to perform dispensation of a specimen or a reagent to the cuvette  21 , stirring, optical measurement, cleaning, or optical measurement for detecting unwanted material, with respect to the cuvette  21 . The reaction table  13  is rotatable about a vertical line that passes through the center of the reaction table  13  as a rotation axis by driving of a not-shown driving system with a control by a control unit  31 . An openable and closable lid and a thermostatic bath not shown are provided above and below the reaction table  13 , respectively. 
     The reagent container  14  can house a plurality of reagent vessels  15 , each of which contains a reagent to be dispensed into the cuvettes  21 . In the reagent container  14 , plural rooms are arranged at regular intervals, and in each of the rooms, the reagent vessel  15  is detachably housed. The reagent container  14  is rotatable in a clockwise or counterclockwise direction about a vertical line that passes through the center of the reagent container  14  as a rotation axis by driving of a not-shown driving system with a control by the control unit  31 . The regent container  14  transfers a desirable one of the reagent vessels  15  to a reagent sucking position for the reagent dispensing system  16 . Above the reagent container  14 , an openable and closable lid (not shown) is provided. Also, under the reagent container  14 , a cool box is provided. Therefore, when the reagent vessel  15  is housed inside the reagent container  14  and the reagent container  14  is closed with the lid, a reagent contained in the reagent vessel  15  is cooled so that evaporation and degeneration of the reagent contained in the reagent vessel  15  can be suppressed. 
     The reagent dispensing system  16  has, similarly to the specimen dispensing system  12 , an arm  16   a  to which a reagent nozzle through which a reagent is sucked in and discharged out is attached at a tip end portion thereof. The arm  16   a  is movable up and down in a vertical direction and rotatable about a vertical line that passes through a base end portion thereof as a central axis. The reagent dispensing system  16  sucks in a reagent in the reagent vessel  15  that has been moved to a predetermined position on the reagent container  14  through the nozzle. The reagent dispensing system  16  discharges out to dispense the reagent into the cuvette  21  that has been conveyed to a predetermined position on the reaction table  13  by rotating the arm  16   a  in a clockwise direction in the drawing. The stirring unit  17  stirs the specimen and the reagent that are dispensed into the cuvette  21  to promote reaction. 
     The photometric unit  18  irradiates the cuvette  21  that has been conveyed to a predetermined optical measurement position with analysis light (340 to 800 nm), disperses light that has transmitted through liquid in the cuvette  21 , and measures intensity of light of each wavelength using a photodetecting element such as PDA (Photo Diode Array). Thus, absorbance of a wavelength that is specific to the reaction liquid of the specimen and the reagent, which is an analysis object, is measured. 
     The cleaning unit  19  sucks in and discharges out mixed liquid in the cuvette  21 , for which measurement by the photometric unit  18  has been finished. The cleaning unit  19  injects cleaning liquid such as detergent or cleaning water into the cuvette  21  and then sucks it away to thereby clean the cuvette  21 , for which an analysis process has been finished. 
     Next, the controller  3  is described. The controller  3  includes the control unit  31 , an input unit  32 , an analyzing unit  33 , a storage unit  35 , and an output unit  36 . Each of components in the measurement system  2  and the controller  3  is electrically connected to the control unit  31 . 
     The control unit  31  is formed with a use of a CPU and the like, and controls processing and operations of each of components in the analyzer  1 . The control unit  31  performs predetermined input and output control of information to be input to and output from each of the components, and also performs predetermined information processing on the information. The input unit  32  is formed with a use of a keyboard, a mouse, and the like, and acquires various kinds of information required for analyzing a specimen, instruction information for an analysis operation, and the like from an external source. The analyzing unit  33  performs a component analysis and the like of a specimen based on the absorbance measured by the photometric unit  18 . The storage unit  35  is formed with a use of a hard disk that magnetically stores therein information, and a memory that loads, when the analyzer  1  performs processing, various kinds of computer programs related to the processing from the hard disk to electrically store therein. The storage unit  35  stores various kinds of information including a result of analysis of a specimen. The storage unit  35  can include an auxiliary storage device that can read information stored in a storage medium such as a CD-ROM, a DVD-ROM, and a PC card. The output unit  36  is formed with a use of a display, a printer, a speaker, and the like, and outputs various kinds of information including a result of analysis of a specimen. The output unit  36  outputs various kinds of information to an external device via a not-shown communication network. 
     In the analyzer  1  configured as described above, the specimen dispensing system  12  dispenses a specimen contained in each of the specimen vessels  11   a  and the reagent dispensing system  16  dispenses a reagent contained in each of the reagent vessels  15 , into each of the cuvettes  21  that are sequentially conveyed in an aligned state. Then, the photometric unit  18  measures spectral intensity of the specimen while the specimen and the reagent react with each other. The analyzing unit  33  analyzes a result of the measurement, so that component analysis and the like of the specimen can be performed. This operation is performed automatically with a control by the controller  3 . The cleaning unit  19  cleans the cuvettes  21 , which have been conveyed after the measurement by the photometric unit  18  is finished, while conveying the cuvettes  21 . Thus, a series of analysis operation is repeatedly performed successively. 
     Next, the cleaning unit  19  shown in  FIG. 1  is described.  FIG. 2  is a schematic diagram explaining a configuration of the cleaning unit  19  shown in  FIG. 1 . As shown in  FIG. 2 , the cleaning unit  19  shown in  FIG. 1  is mounted on a holder  131  that forms the reaction table  13 . The cleaning unit  19  has three cleaning nozzles including a supply nozzle  191 , a suction nozzle  192 , and an overflow suction nozzle  193 , as cleaning nozzles for cleaning the cuvette  21  that has been conveyed to a cleaning position. On the holder  131 , photometric windows W 1  and w 2  that form paths of incident light on the cuvette  21  and transmitted light transmitted from the cuvette  21  are formed to perform optical measurement. 
     The supply nozzle  191  is configured to be inserted into the cuvette  21  to supply cleaning liquid into the cuvette  21 . The suction nozzle  192  is configured to be inserted into the cuvette  21  to suck in liquid as a discharging object in the cuvette  21 . The overflow suction nozzle  193  sucks in an overflow portion of the cleaning liquid so that the cleaning liquid does not overflow from the cuvette  21 . The cleaning unit  19  includes an up-down moving system  194  that integrally moves up and down the three cleaning nozzles. The cleaning unit  19  performs a cleaning process on the cuvette  21  by causing the up-down moving system  194  to integrally move up and down the three cleaning nozzles so that a cleaning-liquid supply process by the supply nozzle  191 , a drainage suction process by the suction nozzle  192 , and a suction process of sucking an overflow liquid at an overflow height position by the overflow suction nozzle  193  can smoothly be performed. 
     The supply nozzle  191  is connected to a cleaning liquid vessel  191   b  that houses cleaning liquid Ls via a tube  191   a.  On the tube  191   a,  an open-close valve  191   c  that controls a supply process of the cleaning liquid Ls and a pump  191   d  that performs sucking and discharging operation of the cleaning liquid Ls with respect to the cleaning liquid vessel  191   b  are mounted. When the open-close valve  191   c  is opened, the cleaning liquid Ls that has been sucked in by the pump  191   d  is supplied from the supply nozzle  191  into the cuvette  21 . 
     The suction nozzle  192  is connected to a drainage vessel  195  that collects drainage Ld via a tube  192   a.  On the tube  192   a,  a tank  192   b  for temporarily collecting drainage is mounted. The tank  192   b  is connected to, via a tube  192   f,  an open-close valve  192   e  that is to be opened when the temporarily-collected drainage is drained to the drainage vessel  195 . The tank  192   b  is also connected to, via a tube  192   d,  an open-close valve  192   c  that is to be opened when liquid in the cuvette  21  is sucked in by the suction nozzle  192 , and a vacuum pump  196 . A tube  192   h  is branched from the tube  192   d  in a distribution connector  192   i.  The tube  192   d  is connected to an air open valve  192   g  via the branched tube  192   h.  One tube connecting port of the air open valve  192   g  is connected to atmosphere. When the open-close valve  192   c  is opened while the air open valve  192   g  and the open-close valve  192   e  are closed, the liquid that has been sucked in from the cuvette  21  by the suction nozzle  192  is sucked in by a suction process by the vacuum pump  196 , and collected in the tank  192   b.  When the open-close valve  192   c  is closed and the air open valve  192   g  is opened after suction operation has been finished, a vacuum state in a pipeline from the suction nozzle  192  to the tank  192   b  can be relieved. Then, when the open-close valve  192   e  is opened, the liquid collected in the tank  192   b  flows down towards the drainage vessel  195  by gravity. 
     The overflow suction nozzle  193  is connected to the drainage vessel  195  that collects the drainage Ld via a tube  193   a.  On the tube  193   a,  a tank  193   b  for temporarily collecting drainage is mounted. The tank  193   b  is connected to, via a tube  193   f,  an open-close valve  193   e  that is to be opened when the temporarily-collected drainage is drained to the drainage vessel  195 . The tank  193   b  is also connected to, via a tube  193   d,  an open-close valve  193   c  that is to be opened when the liquid in the cuvette  21  is sucked in by the overflow suction nozzle  193 , and the vacuum pump  196 . A tube  193   h  is branched from the tube  193   d  in a distribution connector  193   i.  The tube  193   d  is connected to an air open valve  193   g  via the branched tube  193   h.  One tube connecting port of the air open valve  193   g  is connected to atmosphere. When the open-close valve  193   c  is opened while the air open valve  193   g  and the open-close valve  193   e  are closed, the liquid that has been sucked in from the cuvette  21  by the overflow suction nozzle  193  is sucked in by a suction process by the vacuum pump  196 , and collected in the tank  193   b.  When the open-close valve  193   c  is closed and the air open valve  193   g  is opened after suction operation has been finished, a vacuum state in a pipeline from the overflow suction nozzle  193  to the tank  193   b  can be relieved. Then, when the open-close valve  193   e  is opened, the liquid collected in the tank  193   b  flows down towards the drainage vessel  195  by gravity. 
     Next, shapes of the supply nozzle  191  and the suction nozzle  192  are described.  FIG. 3  is a schematic diagram illustrating a cross-sectional shape of each of the supply nozzle  191  and the suction nozzle  192 . In  FIG. 3 , a state in which the supply nozzle  191  and the suction nozzle  192  are inserted into the cuvette  21  that is filled with the cleaning liquid Ls is illustrated. The overflow suction nozzle  193  is located at a position of an opening portion of the cuvette  21  to suck in an overflow portion of the cleaning liquid, so that the overflow suction nozzle  193  is not inserted into a position of the cleaning liquid Ls filled in the cuvette  21 . Therefore, the overflow suction nozzle  193  is illustrated in a chain double-dashed line in  FIG. 3 . 
     As shown in  FIG. 3 , in the cleaning unit  19 , a wall of each of the supply nozzle  191  and the suction nozzle  192  is thickened to increase the volume of a submerged portion of the supply nozzle  191  and the volume of a submerged portion of the suction nozzle  192  when the supply nozzle  191  and the suction nozzle  192  are inserted into the cuvette  21 . Specifically, in the supply nozzle  191 , an inner diameter R 11  and a wall thickness T 21  are set so that a wall cross-sectional area S 12  becomes larger than an inner-diameter cross-sectional area S 11  of the supply nozzle  191  as shown in  FIG. 3 . Furthermore, in the suction nozzle  192 , an inner diameter R 21  and a wall thickness T 22  are set so that a wall cross-sectional area S 22  becomes larger than an inner-diameter cross-sectional area S 21  of the suction nozzle  192 . A distance Dl between the supply nozzle  191  and an inner wall of the cuvette  21  and a distance D 2  between the suction nozzle  192  and the inner wall of the cuvette  21  can be set such that the cleaning liquid Ls can flow therethrough. 
     Here, a shape of a cleaning nozzle of a conventional analyzer is described.  FIG. 4  is a schematic diagram illustrating a cross-sectional shape of each of a conventional supply nozzle and a conventional suction nozzle. In  FIG. 4 , an overflow suction nozzle  1193  is illustrated in a chain double-dashed line similarly to  FIG. 3 . 
     As shown in  FIG. 4 , a supply nozzle  1191  and a suction nozzle  1192  that respectively have thin walls have conventionally been used. In the supply nozzle  1191 , a wall thickness T 120  is extremely smaller than a value of an inner diameter R 110  of the supply nozzle  1191 , so that a wall cross-sectional area S 120  of the supply nozzle  1191  becomes smaller than an inner-diameter cross-sectional area S 110  of the supply nozzle  1191 . Similarly, in the suction nozzle  1192 , a wall thickness T 220  is extremely smaller than a value of an inner diameter R 210  of the suction nozzle  1192 , so that a wall cross-sectional area S 220  of the suction nozzle  1192  becomes smaller than an inner-diameter cross-sectional area S 210  of the suction nozzle  1192 . 
     As described, the supply nozzle  1191  and the suction nozzle  1192  that respectively have thin walls have conventionally been used, so that, as shown in  FIG. 5 , a volume VL 0  occupied by the cleaning liquid Ls in the cuvette  21  becomes extremely larger than a sum of a volume V 120  of a submerged portion of the supply nozzle  1191  and a volume V 220  of a submerged portion of the suction nozzle  1192  in the cuvette  21 . Unwanted material on a surface of an inner wall of the cuvette  21  can be sufficiently removed if the cleaning liquid Ls flow over the surface of the inner wall of the cuvette  21 . However, nearly the same amount of the cleaning liquid Ls as the inner volume of the cuvette  21 , which is extremely larger than the amount by which cleaning can actually be performed, has had to be used because the supply nozzle  1191  and the suction nozzle  1192  that respectively have thin walls are used and the sum of the volume of the submerged portions of the supply nozzle  1191  and the suction nozzle  1192  is small as shown in  FIG. 5 . 
     In contrast, in the analyzer  1  of the present embodiment, as shown in  FIG. 3 , the wall thickness of each of the supply nozzle  191  and the suction nozzle  192  is thickened so that the wall cross-sectional area can be made larger than the inner cross-sectional area. Therefore, as shown in  FIG. 6 , in the present embodiment, the volume occupied by the cleaning liquid Ls in the cuvette  21  is small compared to the conventional one. Specifically, a sum of a volume V 12  of the submerged portion of the supply nozzle  191  and a volume V 22  of the submerged portion of the suction nozzle  192  in a state where the supply nozzle  191  and the suction nozzle  192  are inserted into the cuvette  21  is made larger than a volume VL 1  occupied by the cleaning liquid Ls in the cuvette  21  by adjusting the wall thickness of each of the supply nozzle  191  and the suction nozzle  192 . 
     In the present embodiment, the supply nozzle  191  and the suction nozzle  192  that respectively have the wall cross-sectional areas larger than the inner-diameter cross-sectional areas are used. The sum of the volumes of the respective submerged portions of the supply nozzle  191  and the suction nozzle  192  becomes large. Thus, the volume occupied by the cleaning liquid Ls in the cuvette  21  can be reduced as shown in  FIG. 6 . Therefore, the amount of the cleaning liquid required for cleaning the cuvette  21  can be reduced. As a result, the cleaning liquid vessel  191   b  to be installed in the analyzer  1  can be downsized. 
     Furthermore, in the present embodiment, the distance D 1  between the supply nozzle  191  and the inner wall of the cuvette  21  and the distance D 2  between the suction nozzle  192  and the inner wall of the cuvette  21  are set such that the cleaning liquid Ls can flow over the inner wall of the cuvette  21 . Therefore, unwanted material on the surface of the inner wall of the cuvette  21  can be sufficiently removed. 
     Moreover, in the present embodiment, a liquid amount of the cleaning liquid Ls to be filled in the cuvette  21  can be reduced, so that a time for filling the cuvette  21  with the cleaning liquid Ls can be reduced. Therefore, to the extent that the time for filling is reduced, a time for substituting the cleaning liquid Ls in the cuvette  21 , that is, a time for supplying a cleaning liquid by the supply nozzle  191  and a time for sucking in an overflow portion by the overflow suction nozzle  193 , can be increased so that the cleaning process can be performed more reliably. Furthermore, in the present embodiment, a filling process and a substitution process can be performed more frequently than the conventional ones within the same cleaning time, so that a cleaning effect can be improved compared to the conventional one. 
     The thickness of the wall of each of the supply nozzle  191  and the suction nozzle  192  should preferably be set corresponding to the volume of the cuvette  21 , a surface area of the cuvette  21 , and types and dispense amounts of a reagent and a specimen that are used depending on an analysis item, so that cleaning can be sufficiently performed. The cleaning nozzles are not required to achieve high dispensing accuracy that a dispensing nozzle that dispenses a reagent or a specimen is required to achieve. Thus, even when the walls are thickened as shown in  FIG. 3 , the cleaning process can be sufficiently performed. Furthermore, in the present embodiment, reducing the thickness of the wall of each cleaning nozzle is not required unlike the conventional one. Therefore, options of material for the cleaning nozzle increase. 
     While, in the present embodiment, as shown in  FIG. 3 , an example is described in which the wall of each of the supply nozzle and the suction nozzle is thickened so that the wall cross-sectional area can be made larger than the inner-diameter cross-sectional area in each of the supply nozzle and the suction nozzle, the present invention is not limited to this example. It is possible to thicken a wall of at least one of the supply nozzle and the suction nozzle so that the wall cross-sectional area can be made larger than the inner-diameter cross-sectional area. For example, as shown in  FIG. 7 , even when a supply nozzle  2191  in which a wall thickness T 212  is made thin and a wall cross-sectional area S 212  is made smaller than an inner-diameter cross-sectional area S 11  is used similarly to the conventional one, if the suction nozzle  192  that is configured to be inserted into a position close to a bottom wall of the cuvette  21  is formed such that the inner diameter R 21  and the wall thickness T 22  are set such that the wall cross-sectional area S 22  becomes larger than the inner-diameter cross-sectional area S 21 , the volume occupied by the cleaning liquid Ls in the cuvette  21  can be reduced. 
     Furthermore, while, in the present embodiment, as shown in  FIG. 6 , an example is described in which the sum of the volume V 12  of the submerged portion of the supply nozzle  191  and the volume V 22  of the submerged portion of the suction nozzle  192  is made larger than the volume VL 1  occupied by the cleaning liquid Ls in the cuvette  21 , the present invention is not limited to this example. To reduce the amount of the cleaning liquid required for the cleaning compared to the conventional one, as shown in  FIG. 8 , a volume V 312  of a submerged portion of a supply nozzle  3191  and a volume V 322  of a submerged portion of a suction nozzle  3192  may be increased compared to the volume of the submerged portion of the conventional supply nozzle and the volume of the submerged portion of the conventional suction nozzle, respectively, so that the volume occupied by the cleaning liquid Ls in the cuvette  21  can become a value VL 3  that is smaller than the conventional one. Conventionally, the wall thickness of each of the cleaning nozzles is made thin so that the wall cross-sectional area is made smaller than the inner-diameter cross-sectional area. Therefore, to reduce the volume occupied by the cleaning liquid Ls in the cuvette  21  compared to the conventional one, as shown in  FIG. 9 , the inner diameter R 11  and a wall thickness T 312  may be set so that a wall cross-sectional area S 312  of the supply nozzle  3191  can be made larger than the inner-diameter cross-sectional area S 11 , or the inner diameter R 21  and a wall thickness T 322  may be set so that a wall cross-sectional area S 322  of the suction nozzle  3192  can be made larger than the inner-diameter cross-sectional area S 12 . 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.