Abstract:
A cuvette for an automatic analyzing apparatus according to the invention includes at least two positions, for each position pair one separating wall connecting the positions, and brackets, which are at the outermost positions and which guide the cuvette into a curved shape. In a handling method of a cuvette according to the invention a cuvette is transported from its brackets to an incubator and bent into a curved shape. In the method the cuvette is then loaded into an opening of the incubator, in which opening it remains by its own spring back factor, until the cuvette is removed from the opening after the analysis.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of co-pending application Ser. No. 12/993,710 filed on Nov. 19, 2010, which is the national phase of PCT International Application No. PCT/FI2009/050450 filed on May 27, 2009, and which claims priority to Application No. 20085509 filed in the Finland on May 28, 2008. The entire contents of all of the above applications are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a new type of a reaction vessel, i.e. a cuvette, for usage in automatic analyzers and to a cuvette incubation method. More precisely, the present invention relates to a cuvette and an incubation method according to the preambles of the independent claims. 
         [0004]    2. Description of Background Art 
         [0005]    As known, disposable and reusable cuvettes have been used in automatic analyzers as individual cuvettes or as sets of cuvettes. Cuvettes are vessels into which a sample to be analyzed and possible other substances to be used in the test are portioned out for the analysis. Reusable cuvettes are cleaned between the analyses, whereas disposable cuvettes are designed to receive only one sample during their life span. The cleaning of the cuvettes between the tests is laborious due to the properties of the cleaning products and to the potentionally dangerous substance to be removed. Thus, especially when performing a large amount of tests, disposable cuvettes are favored, which are delivered to waste treatment after use and it is certain enough that they are clean at least when taken into use. 
         [0006]    Disposable cuvettes are known that there are manufactured as a continuous chain of cuvettes, which can be bent about two axes into a spiral shape and which are adapted to be moved, wrapped around the moving orbicular bodies of the analyzer. Likewise, columns of cuvettes are already known, which can be moved from cuvette specific protrusions, between which conveying members, such as toothed belts, are adapted to penetrate. As known, the attachment of the cuvette or the set of cuvettes to a testing apparatus is performed with external shaped connection of the cuvette, such as pin couplings, and such that the receiving means of the testing apparatus comprising flexible separating walls hold the cuvette in place. 
         [0007]    However, the prior art has some disadvantages. The cuvettes according to prior art are usually suitable to be used in only one application, whereby they have not been suited to be used in several different types of analyzers and incubators. The known cuvette-incubator-pairs have included a plurality of maneuvers and precision mechanics and thus, not being particularly robust in structure nor in operation. In addition, said pairs are typically test-oriented, which means that only analyses of a specific test, typically a photometric analysis, is performed in one test sequence. This is why there have been gratuitous delays in receiving patient or sample specific results. Likewise, the abundance of maneuvers has resulted in that the sample-carrying cuvettes being exposed to several contacts, which has worn their outer surfaces. In some cases excess wear has have impaired the optical properties of the clear vessels. The wear and tear is especially intensive when the vessels are being washed, which is disadvantageous only with reusable cuvettes. 
       SUMMARY AND OBJECTS OF THE INVENTION 
       [0008]    An object of an embodiment of the present invention is to solve at least part of the aforementioned problems and to provide an improved cuvette and a handling method thereof. 
         [0009]    A cuvette according to the invention comprises two positions, which are connected by a separating wall, and at least one bracket at the outermost positions being able to support the cuvette and yield elastically when pressed inward. The separating walls between the cuvette positions allow for the elastic bending of the cuvette about its vertical axis. More precisely, the cuvette according to the present in invention is characterized by what has been stated in the characterizing portion of the independent apparatus claim. 
         [0010]    In a cuvette handling method according to the present invention a cuvette is transported from its brackets to an incubator and it is bent into a curved shape after which the cuvette is loaded into an incubator opening in which it remains by means of its own spring back factor. Hereafter the sample to be analyzed is portioned out into the sample space of the position of the cuvette, it is analyzed while being in the incubator, and the cuvette is finally removed from the incubator opening. More precisely, the handling method according to the present invention is characterized by what has been stated in the characterizing portion of the independent method claim. 
         [0011]    Considerable advantages are gained with the aid of the invention. Due to the brackets and elasticity along the vertical axis, the cuvette according to the present invention can advantageously be used in apparatuses that automatically analyze samples. Due to the suitable yielding properties the cuvette may be transported to an incubator and loaded therein without scratching the vulnerable optical surfaces of the cuvette. Likewise, the brackets contribute to bending the cuvette tightly into the exact bow for it to be throughout its length in continuous contact with the walls of the receiving incubator opening. With the aid of the brackets is also easy to place and center the cuvette into the receiving incubator opening. 
         [0012]    The loading and ejecting movement of the handling method comprises only one direction and movement, whereby the method is robust and reliable. Due to the yielding properties in relation to the vertical axis of the cuvette, neither excess shaped connections nor precision mechanics is required. For the same reason one type of cuvette can be used in various different incubators resulting in considerable cost savings for the user. In addition to the previously mentioned advantages, the sufficiently long brackets and the separating walls separating the positions of the cuvette according to the present invention guarantee that there is an even temperature distribution during the test sequence in the cuvette. Thus, the heat conducting from one sample space to another does not compromise the accuracy and reliability of the test. 
         [0013]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific example, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0015]      FIG. 1  shows an isometric view of a cuvette with 10 positions. 
           [0016]      FIG. 2  shows a side view of the cuvette of  FIG. 1 . 
           [0017]      FIG. 3  shows an elevated view of the cuvette of  FIG. 1 . 
           [0018]      FIG. 4  shows an incubator and a cuvette, which can to be adapted to its orbicular body. 
           [0019]      FIG. 5  shows the loading funnel of the incubator of  FIG. 4 . 
           [0020]      FIG. 6  shows a cuvette according to another embodiment of the present invention equipped with single projection brackets. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    As illustrated in  FIG. 1 , the cuvette  10  comprises positions  20 , which are in line next to each other. By a cuvette  10  is meant in this context a sample-receiving member with at least one position  20  for receiving the sample and for storage at least during analysis. The position  20  is a tubular vessel wherein a confined sample space  28  for a sample to be analyzed is formed and which is limited by the walls of the vessel. The position  20  has, according to one embodiment, a rounded quadrangular shaped cross-section and is generally shaped such that the sides of the opening of the sample space  28  are considerably shorter than the depth thereof. The sample space  28  can also have another shape. In this context, the direction of the longest side of the sample space  28  of the position  20 , i.e. the depth, is called the vertical axis. Correspondingly by a horizontal axis is meant the Cartesian axes orthogonal to the vertical axis. 
         [0022]    The cuvette  10  has, according to one embodiment of the invention,  10  positions, which are separated from each other by separating walls  22 . The separating wall  22  is an isthmus-like connecting part between two positions  20 . As illustrated in  FIGS. 1 and 2 , the separating wall  22  is essentially in the middle of the narrow faces of the parallel positions  20  such that the separating wall  22  extends from the upper edge of the cuvette  10  to about half way of the side face of the positions  20 . In other words, the separating wall  22  does not connect the positions  20  over their whole length, but only along their upper half. The basic idea of the separating wall  22  is to be a connecting element, which does not contribute to transfer heat from position to another, but on the contrary isolates the positions  20  from each other. Thus, the heat conducted between the positions  20  remains as minimal as possible, which improves the accuracy of the analysis. 
         [0023]    One essential feature of the separating wall  22  is its elasticity. As illustrated in  FIG. 3 , the separating walls  22  are rather thin compared to the walls of positions  20 , especially compared to their vertical length. Due to the profile of the separating walls  22  and the elastic material thereof, the cuvette  10  can be bent about its vertical axis, i.e. about the axis directed orthogonally upward from the plane of  FIG. 3 . By elastic material is in this context meant a material, which is elastic enough to cope with intended deformations it experiences. The material of the cuvette  10  and especially of the separating wall  22  is selected such that the construction may be exposed to bending, whereby the separating walls  22  experience elastic deformation, due to which elasticity the cuvette  10  tends to react against the bending thus tautening itself back to its original position. Thus, the elasticity of separating walls  22  is essential, because the structure must remain elastic also under bending strain for reasons explained later on. Besides elasticity the material must have suitable optical properties at least as positions  20  are concerned. Plastic, especially acryl, is for example a sufficiently elastic and suitable bright material. Alternatively the cuvette  10  may be manufactured of more than one material. In this case, parts requiring yielding properties, such as brackets  24  and separating walls  22 , can be made of essentially elastic material, such as polyurethane, and parts requiring optical properties, such as positions  20 , can be made of material having good optical properties, such as acryl. Furthermore, upon material selection, it is possible to favor materials that have good optical characteristics. For example, a material can be favored, which is elastic in its application, but of which material made cuvette  10  is not adapted to recover entirely after the bending, but the separating walls  22  of the cuvette  10  would experience partial plastic deformation. Thus, the cuvette  10  would remain slightly bent after use, which would indicate that the product has been used and reuse would be prohibited. 
         [0024]    As illustrated in  FIGS. 1 ,  2  and  3 , the outermost positions  20  are equipped with brackets  24 . According to one embodiment of the invention, the bracket  24  consists of two protrusions, which are considerably shorter in the direction of the vertical axis of the cuvette  10  than the cuvette  10  and which are rather fragile in regard to their wall thickness. The protrusions of the bracket  24  are oriented outward from the upper part of the outer edge of the outermost positions  20  such that the protrusions curve towards each other. By the outer edge of the position  20  is meant the side edge of either of the outermost position  20  not having a separating wall  22 . Correspondingly, the direction oriented outward is the horizontal direction oriented from the separating wall  22  toward the outer edge of the position  20 . 
         [0025]    The brackets  24  are, as the separating walls  22 , of elastic material, due to which they too endure elastically the bending about their longest side. The yielding properties of the brackets  24  are the best in the orientation direction of the cuvette  10 . Thus, the protrusions of the brackets  24  persist the compression toward the position  20 . The elasticity of the brackets  24  is essential, because the structure must remain elastic under compression due to reasons explained later on. It is likewise important that the inward compressed brackets  24  do not bend into contact with the position  20  under compression, but keep a distance between the fixation and the position  20 , whereby there is no thermal conduction between its outer edge and the fixation. If there were to occur thermal conduction between the fixation and the outermost positions  20  of the cuvette  10 , they would receive more heat than the rest of the positions  20 . In such a case, an uneven temperature distribution would be formed into the cuvette  10 , which would impair the accuracy of the measurement. 
         [0026]    As is apparent from  FIGS. 1 and 2 , the positions  20  of the cuvette  10  may be equipped with screens  26  suitable for optical analysis. According to one embodiment of the present invention, the screen  26  is a part in the lower end of the position  20 , which has been made transparent and which has suitable optical properties for analysis. In addition, the screen  26  must be large enough for the analyzing ray to fit reliably across the position  20  and for the small aligning errors caused by the mechanical parts of the analyzing apparatus not to make the measurement more difficult. It is thus possible to perform analyses based on optical examination such that the sample remains in the sample space  28  of the position  20 , whereby the number of maneuvers and sample transfers is small as possible. In order to avoid excess wear and tear of the screen  26 , its sensitive surface can be manufactured such that it is slightly deeper than the rest of the face of the position  20 . Said cavity provides protection from the majority of scratching contacts, whereby wearing occurring during the packaging phase, for example, is directed toward the side faces of the positions  20  instead of toward the screens  26 . 
         [0027]    As illustrated in  FIG. 4 , the cuvette  10  is especially suitable to be used in an automatic incubator  30 . According to one preferred embodiment, the incubator  30  comprises a heated disc  32  into the outer perimeter of which openings  34  for receiving the cuvettes  10  have been made. The disc  32  is fitted with a bearing in the middle wherein means for rotation (not shown) are arranged, with the aid of which the disc  32  can be rotated a desired amount in a desired direction. The rotation means can, for example, comprise a servomotor, which has excellent positioning accuracy but which is considerably expensive. The power transmission of the incubator  30  can be arranged with sufficient accuracy by fitting the disc directly on the axle of a cost efficient and sufficiently accurate stepping motor, whereby the transmission has only a necessary amount of moving parts and as few sources of play as possible. The incubator  30  further comprises, in connection with the disc  32 , a loading track  38 , along which cuvettes  10  are brought to be loaded into the opening  34  of the disc  32 . The loading track  38  is in its simplest embodiment a channel having a U-shaped cross-section and whose horizontal edge is essentially as wide as the lower edge of the cuvette  10  and whose vertical edges are essentially lower than the cuvette  10 . Thus the cuvette  10  may be transported from its brackets  24  along the loading track  38  such that the brackets  24  of the cuvette  10  are placed on top of the vertical edges of the loading track  38 , whereby the lower edges of the positions  20  are at a distance from the bottom of the loading track  38 . The gap between the lower edge of the positions  20  and the bottom of the loading track  38  makes it possible for the lower edge of the position  20  not to grind the bottom of the loading track  38  and thus preventing scratching. 
         [0028]    To the loading track  38  side of the disc  32  a loading funnel  40  has been fitted, through which cuvettes  10  are loaded into the openings  34  of the disc  32 . The loading is performed by using a press  36 , the lower edge of which is adapted to press the cuvette  10  into the loading funnel  40 , in which it is adapted to acquire a shape allowing it to fit into the opening  34  and to proceed into the opening  34 . The curvature of the opening  34  conforms to the curvature of the disc  32 . Due to of the elasticity of the cuvette  10 , it may be used with various discs  32  and further openings  34  with different curvature radii. As is apparent from  FIG. 5 , the loading funnel  40  is shaped such that a cuvette  10  passing through it assumes a curved shape able to fit into the opening  34 . The cuvette  10  receiving edge  42  of the loading funnel  40  is convex when viewed from the entering direction of the cuvette, whereby a cuvette  10  pressed against it bends into a shape conforming to the perimeter of the disc  32 . The curvature of the receiving edge  42  of the loading funnel  40  can be planar, i.e. constant, or it can vary in the horizontal direction, whereby the receiving edge  42  is planar at its upper edge and progressively convex when viewed lower. Thus the cuvette  10  is adapted to bend gradually conforming to the receiving edge  42 , whereas the face  42  being evenly curvaceous, the cuvette  10  is adapted to bend immediately to the curve shape desired. The loading funnel  40  is also equipped with brackets  24  with receiving side edges  44 , against whose inner edge the brackets  24  are pressed. Thus, the cuvette  10  is in intensive contact with the loading funnel  40  only at the brackets  24 , whereby they receive the wear and scratching resulting from bending. Therefore the fragile surfaces of the cuvette  10 , such as screens  26  and their surroundings, avoid erosion. Furthermore, the side edges  44  of the loading funnel are equipped with guides  46  securing that the brackets  24  of the cuvette  10  are pressed against the inner faces of the side edges  44 . When the cuvette  10  is pressed against the lower edge of the loading funnel  40 , its brackets  24  are pressed in and the separating walls  22  are bent, whereby the cuvette  10  is tightly curved against the receiving face  42  of the loading funnel  40  and ready to be loaded equally tightly in to the opening  34  of the disc  32 . With the aid of the brackets  24  the cuvette  10  is placed and centers itself automatically into the opening  34  even though the disc  32  should not be in the exactly correct position. The cuvette  10  can certainly have a different construction achieving the qualities described above. For example, a cuvette  10  illustrated in  FIG. 7  could be a possible embodiment, but only if it would result in above described qualities. Likewise, the cuvette  10  could also be straight and not adapted to assume a curved shape, whereby the cuvette  10  would be designed to remain in a corresponding straight opening  34  only due to the elastic properties of its brackets. 
         [0029]    The path of the press  36  is so long that the upper edge of the cuvette  10  is at a desired height when it is pressed in to the opening  36 . Accordingly, the pressing depth of the press  36 , which may be programmed to suit the application, determines the vertical alignment. As above, the when loading the cuvette  10  into the opening  34  its brackets  24  receive the most abrasion, which the other surfaces avoid. As the cuvette  10  is in the opening  34  of the incubator  30 , the fluid or other substance to be analyzed can be distributed into the sample spaces  28 . It is to be noted that the cuvette  10  may be designed for incubators  30  with discs  32  and further openings  34  of various sizes, as described above. Thus, a cuvette  10  of a certain size can be used in various applications, which provides considerably cost savings while the variety of cuvettes is minimal. 
         [0030]    The disc  32  is heated for maintaining as favorable analyzing conditions as possible, due to which heat is conducted to positions  20  and further to sample spaces  28  through the side face of the opening  34 . With the aid of separating walls  22  the positions  20  are separated from each other not causing temperature distortion with their preheat between adjacent positions  20 . An even temperature is further improved by sufficiently prominent brackets  24 , which isolate the outer edges of the outer positions  20  of the cuvette  10  from the heated faces of the opening  34 . 
         [0031]    The analyzing apparatuses have been arranged around the incubator  30  such that there is no need to remove the cuvette  10  from the opening  34  during testing. For example, optical tests may be performed directly through the screen  26  of the position  20 . Therefore, the position  20  of the cuvette  10  loaded from the loading track  28  into the opening  34  of the incubator  30  is adapted to receive substances from several manipulators by changing the position of the disc  32 . The analyzing procedure can in this case be arranged such that the reagent is portioned out into the sample space  28  of the position  20  by means if a reagent dispenser, which retrieves the substance from a reagent storage. The dispensing of the reagent requires that the disc  32  of the incubator  30  has been rotated into a correct position such that the correct position  20  is in a reagent receiving position. The basic idea of the arrangement is that the sample is moved in the cuvette  10 , the position of which is changed by rotating the disc  32  of the incubator, whereby the number of maneuvers and directions is as small as possible. The samples for their part are dispensed in a similar manner by means of a sample dispenser, which retrieves the substance from a sample storage. The reagent and sample can be mixed by rotating the disc  32  into the vicinity of a mixer and by starting the mixer. The contents of the position  20  can be analyzed optically as described above and, for example, with a manipulating analyzer adapted to suck the sample into its test space and to measure its voltage compared to a reference value. The sectioning and programming of the test sequences and maneuvers is previously known. 
         [0032]    When the tests performed to all used positions  20  are completed, the cuvette  10  can be ejected from the opening  34  such that the press  36  having performed the loading pushes the cuvette  10  out of the opening  34  into a separate receiving bin or into the waste opening  50  of the incubator  30 . Alternatively, the press  36  can load a new cuvette  10  through the loading funnel  40  into the opening  34 , whereby the used cuvette  10  is pushed out by the new one into a separate waste bin or into the waste opening  50  of the incubator  30 . 
         [0033]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.