Abstract:
A specimen analyzer comprising: a reagent refrigerator configured to store and cool a reagent container; a measurement unit configured to measure a specimen by using a reagent in the reagent container cooled by the reagent refrigerator; wherein the reagent refrigerator comprises: a housing configured so that an upper portion of the housing is openable and closable; a reagent container table configured so that the reagent container is set thereon, wherein the reagent container table is arranged within the housing so as to space away from a bottom of the housing; a first member arranged so as to face a side surface of the reagent container set on the reagent container table; and a second member arranged lower than the reagent container table, wherein the second member has a higher thermal conductivity than that of the first member.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 to Japanese Patent Application Nos. 2011-058480 and 2011-058481 both filed on Mar. 16, 2011, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a specimen analyzer for analyzing a sample using a cooled reagent. 
         [0004]    2. Description of the Related Art 
         [0005]    There are known specimen analyzers provided with a reagent refrigerator for cooling reagent within an accommodated reagent container, wherein the specimen analyzer analyzes specimens using the reagent cooled within a reagent refrigerator (for example, U.S. Patent Application Publication No. 2009/0004057). The reagent refrigerator disclosed in U.S. Patent Application Publication No. 2009/0004057 is configured to accommodate a reagent container within a reagent case that is cooled by Peltier element, and cool the reagent within the reagent container by circulating the air within the reagent case via a circulation unit, the reagent case being formed of a material that has excellent thermal conductivity, such as aluminum or the like. 
         [0006]    The reagent refrigerator disclosed in U.S. Patent Application Publication No. 2009/0004057 readily generates condensation, particularly in the reagent case, because the reagent case has high thermal conductivity and is cooled by a Peltier element. Hence, when the user sets a reagent container in the reagent case, there is concern that the reagent container may come into contact with the side walls and the like of the reagent case causing condensation water to adhere to the reagent container. Condensation water adhering to the reagent container may interfere with the reading of the barcode label adhered to the reagent container, and there is further concern that condensation water may penetrate into the reagent container. 
       SUMMARY OF THE INVENTION 
       [0007]    The scope of the present invention is defined solely by the appended claims, and is not affected to any degree by the statements within this summary. 
         [0008]    According to a first aspect of the present invention, a specimen analyzer comprising: a reagent refrigerator configured to store and cool a reagent container; a measurement unit configured to measure a specimen by using a reagent in the reagent container cooled by the reagent refrigerator; wherein the reagent refrigerator comprises: a housing configured so that an upper portion of the housing is openable and closable; a reagent container table configured so that the reagent container is set thereon, wherein the reagent container table is arranged within the housing so as to space away from a bottom of the housing; a first member arranged so as to face a side surface of the reagent container set on the reagent container table; and a second member arranged lower than the reagent container table, wherein the second member has a higher thermal conductivity than that of the first member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view showing the general structure of a specimen analyzer of an embodiment of the present invention; 
           [0010]      FIG. 2  is a brief structural view of the specimen analyzer of  FIG. 1 ; 
           [0011]      FIG. 3  is a brief plan view showing the reagent refrigerator and dispenser unit; 
           [0012]      FIG. 4  is a brief plan view showing top surface of the housing in an opened condition; 
           [0013]      FIG. 5  is a side cross sectional view briefly showing the reagent refrigerator of  FIG. 1 ; 
           [0014]      FIG. 6  is a horizontal cross sectional view of the inner bottom surface of the reagent refrigerator viewed from above; 
           [0015]      FIG. 7  is a side cross sectional view briefly showing the enlarged essential parts within the reagent refrigerator; 
           [0016]      FIG. 8  is a plan view showing part of the upright wall member; 
           [0017]      FIG. 9  is a cross sectional view on the A-A arrow line in  FIG. 6 . 
           [0018]      FIG. 10  is a cross sectional view on the B-B arrow line in  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    The embodiments of the specimen analyzer of the present invention are described in detail hereinafter with reference to the accompanying drawings.  FIG. 1  is a perspective view showing the general structure of a specimen analyzer  1  of an embodiment of the present invention. 
         [0020]    The specimen analyzer  1  is an apparatus for performing specific measurements of a measurement sample prepared by mixing a reagent and a specimen collected from a human body, then analyzing the specimen based on the measurement results, and is, for example, a blood coagulation measuring apparatus, immunoanalyzer, or biochemical analyzer. The specimen analyzer  1  is configured by a measuring device  2 , and a control device  4  that is electrically connected to the measuring device  2 . Provided within a casing  5  of the measuring device  2  is a reagent refrigerator  10  for accommodating and cooling a plurality of reagent containers which hold reagent. The casing  5  of the measuring device  2  has a cover body  5 A that can be opened and closed; at least part of the reagent refrigerator  10  can be exposed by opening the cover body  5 A. 
         [0021]      FIG. 2  is a brief structural view of the specimen analyzer  1  of  FIG. 1 . The measuring device  2  of the specimen analyzer  1  is provided with, in addition to the reagent refrigerator  10 , a specimen supply unit  12 , transport drive unit  13 , dispensing section  14 , measuring unit  15 , reader  33 , and control circuit  16 . The specimen supply unit  12  has the function of setting a specimen rack that holds specimen containers (test tubes or the like) containing a specimen, and positioning each specimen container at a predetermined dispensing position by transporting the specimen rack. The transport drive unit  13  has the function of transporting the reagent container accommodated in the reagent refrigerator  10  to the predetermined dispensing position. 
         [0022]    The dispensing section  14  has the function of dispensing specimen and reagent from the specimen container and reagent container positioned at the predetermined dispensing positions to prepare a measurement sample.  FIG. 3  is a plan view showing the reagent refrigerator  10  and the dispensing section  14 . As shown in  FIG. 3 , the dispensing section  14  has a plurality of dispensing units  25  through  29 ; each dispensing unit  25  through  29  is capable of dispensing reagent from within the reagent container accommodated in the reagent refrigerator  10 . 
         [0023]    When describing a single dispensing unit  25  by way of example, the dispensing unit  25  has a support  25   a , an arm  25   b  wherein the base end is supported by the support  25   a , and a pipette  25   c  provided at the tip of the arm  25   b . The arm  25   b  is driven to pivot on the base end to rotate in horizontal directions and is further driven to ascend and descent in vertical directions. The pipette  25   c  is inserted into an aspiration hole  71  formed in the top surface of the reagent refrigerator  10 , and aspirates reagent from the reagent container  300  (refer to  FIG. 5 ) within the reagent refrigerator  10  via the horizontal rotation and vertical elevator action of the arm  25   b . The other dispensing units  26  through  29  have structures identical to that of the dispensing unit  25 , and their detailed description is therefore omitted. 
         [0024]    As shown in  FIG. 2 , the measuring unit  15  has the function of performing specific measurements of the measurement sample prepared by mixing a specimen and reagent. The reader  33  is a barcode reader for reading a barcode adhered to the reagent container racks  310  and  320  (refer to  FIG. 5 ) that accommodate the reagent container  300 , and the reagent container  300  accommodated in the reagent refrigerator  10 . As shown in  FIG. 5 , the reagent container  300  has a side surface  300   a . The barcode is adhered to the side surface  300   a . The reader  33  is disposed outside the reagent refrigerator  10 , and is capable of reading a barcode within the reagent refrigerator  10  through a slit (not shown in the drawing) which is formed in the reagent refrigerator  10  and is opened and closed via a shutter. 
         [0025]    As shown in  FIG. 2 , the control circuit  16  has a CPU, memory such as RAM, ROM or the like, and a communication interface; the control circuit  16  has the function of controlling the operations of the reagent refrigerator  10 , transport drive unit  13 , dispensing unit  14 , measuring unit  15 , and reader  33 , and transmitting and receiving various types of information to/from the control device, to which the control circuit  16  is connected so as to be capable of communication. 
         [0026]    As shown in  FIG. 1 , the control device  4  is a personal computer  401  (PC), and includes a controller  4   a , display  4   b , and keyboard  4   c  for inputting information. The controller  4   a  has the functions of transmitting an operation start signal of the measuring device  2  to the control circuit  16  of the measuring device  2 , and analyzing the information of the measurement result obtained by the measuring device  2 . The display  4   b  has the function of displaying the analysis result obtained by the controller  4   a.    
       Detailed Structure of the Reagent Refrigerator  10   
       [0027]      FIG. 5  is a side sectional view briefly showing the reagent refrigerator  10 . 
         [0028]    The reagent refrigerator  10  is provided to refrigerate the reagent container  300  containing a reagent to be added to a specimen, and transport the reagent container  300  in a rotational direction around an axis O. The reagent is prevented from degenerating by being preserved at low temperature. The reagent refrigerator  10  is provided with a housing  20 , and reagent container tables  21  and  22  arranged within the housing  20  and loaded with reagent containers  300  containing reagent. 
         [0029]    The reagent container tables  21  and  22  are configured by annular first reagent table  21 , and an annular reagent container table  22  arranged concentrically with the first reagent container table  21  and on the outer side in the diameter direction of the first reagent container table  21 . The first reagent container table  21  and the second reagent container table  22  are arranged so that the first reagent container rack  310  and the second reagent container rack  320  holding a plurality of reagent containers  300  are respectively detachable. 
         [0030]    The first reagent container table  21  and the second reagent container table  22  are respectively and independently rotatable in both clockwise and counterclockwise directions on the axis O via the transport drive unit  13 . Hence, the reagent containers  300  set on the reagent container tables  21  and  22  are transported in rotational directions. Each reagent container  300  is positioned at the dispensing position of the dispensing units  25  through  29  by transporting the reagent container  300  in a rotational direction. Details of the structure of the transport drive unit  13  are described later. 
         [0031]    As shown in  FIG. 5 , the reagent refrigerator  10  and the housing  20  are provided with a solid-bottom cylindrical shaped main body  65  with a bottom wall  63  forming the bottom part of the housing  20  and a circumferential wall (side wall)  64  rising from the periphery of a bottom wall  63 , and a cover  66  that functions as a top wall of the reagent refrigerator  10  by closing the top opening of the main body  65 . The sealed space circumscribed by the main body  65  and the cover  66  is a refrigeration chamber, and the plurality of reagent containers  300  set in the reagent container tables  21  and  22  within the refrigeration chamber are enclosed completely therein on the outside in the diameter direction (outside in the horizontal direction) by the circumferential wall  64 . 
         [0032]    As shown in  FIG. 3 , the cover  66  is configured by a fixed cover  67  that closes approximately the back half of the main body  65 , and a movable cover  68  that closes the approximate front half of the main body  65  and is openable. The movable cover  68  is coupled to the front edge of the fixed cover  67  so as to oscillate through a hinge member  69 . 
         [0033]    The cover  66  of the housing  20  has a plurality of aspiration holes  71  formed therein; these aspiration holes  71  are configured so that the pipette  25   c  of the dispensing units  25  through  29  can be inserted, and the reagent within the reagent container  300  held in the reagent refrigerator  10  can be aspirated from the top opening of the reagent container  300 . 
         [0034]    Note that exchanging the reagent in the reagent refrigerator  10  is accomplished for each reagent container rack  310  and  320  by opening the cover  5 A (refer to  FIG. 1 ) of the measuring device  2  to expose the front side of the reagent refrigerator  10 , opening the movable cover  68  upward to open the front half of the reagent refrigerator  10 .  FIG. 4  is a plan view of the reagent refrigerator showing the cover  66  in the open condition. When the cover  66  is open, the interior of the main body  65  is exposed, and the reagent racks  310  and  320  holding the reagent containers  300  can be inserted into the main body  65  and removed from the main body  65 . 
         [0035]    As shown in  FIG. 5 , the circumferential wall (side wall)  64  of the main body  65  of the housing  20  is formed of a material having low thermal conductivity. The bottom wall  63  has different material for the outer part  77  and the heat transfer layer  78 ; the outer part  77  is formed of the same low thermal conductivity material as the circumferential wall  64  and is linked to the bottom end of the circumferential wall  64 . 
         [0036]    The heat transfer layer  78  of the bottom wall  63  is formed of a material that has a higher thermal conductivity than the circumferential wall  64  and the outer part  77 , and protrudes upward from the outer part  77 . The circumferential wall  64 , bottom wall  63 , and outer part  77  of the main body  65  may be formed of thermoplastic resin such as ABS and the like. The heat transfer layer  78  may be formed of a metal such as aluminum, iron, steel and the like. The outer surface of the circumferential wall  64  and the bottom wall  63  are covered by thermal shield layers  76  and  79  that have lower thermal conductivity. 
         [0037]      FIG. 6  is a horizontal cross sectional view of the inner bottom surface of the reagent refrigerator  10  viewed from above. As shown in  FIG. 6 , the heat transfer layer  78  provided on the bottom wall  63  of the housing  20  is formed in a polygonal shape (hexagonal shape in the example of the drawing) in the plan view. As shown in  FIGS. 5 and 6 , part of the bottom surface of the heat transfer layer  78  is exposed below, and a cooler  80  is provided on this exposed surface. In the present embodiment, two coolers  80  are arranged at symmetrical positions centered on the central axis O of the reagent refrigerator  10  (that is, the center of rotation of the first and second reagent container tables  21  and  22 ). The cooler  80  is configured to cool the air within the reagent refrigerator  10  using the heat transfer layer  78  as a cooling medium by directly cooling the heat transfer layer  78  which has a high thermal conductivity. Note that the cooler  80  is not limited to using a Peltier element, and also may provide cooling, for example, by air cooling or water cooling the heat transfer layer  78 . The planar shape of the heat transfer layer  78  is not limited a polygonal shape, and also may be circular. 
         [0038]    An upright wall member  81  is provided in the circumferential direction along the circumferential wall  64  on the inside of the circumferential wall  64  of the main body  65 . As shown in  FIG. 5 , the upright wall member  81  is positioned below the top surface of the first and second reagent container tables  21  and  22 , and is separated from the inner surface of the circumferential wall  64  at the inner side of the circumferential wall  64 . As shown in  FIG. 6 , the upright wall member  81  is formed with an approximately circular shape in the plan view, and extends the approximate entire circumference of the housing  20 . Note that the upright wall member  81  of the present embodiment has an approximately circular shape by curving a band-like plate in a polygonal shape. 
         [0039]    A mounting part  81   a  that protrudes inward in the diameter direction is provided at the bottom end of the upright wall member  81 , and the upright wall member  81  is connected to the heat transfer layer  78  by the mounting part  81   a  being screwed to the top surface of the heat transfer layer  78 . The upright wall member  81  is formed of metal, for example, aluminum, that is a material that has the same high thermal conductivity as the heat transfer layer  78 . The upright wall member  81  connected to the heat transfer layer  78  and is cooled by the cooler  80 . 
         [0040]    A heat sink (condensation promoting member)  82  is provided on the top surface of the heat transfer layer  78 . The heat sink  82  is formed of a material having a high thermal conductivity such as aluminum, and increases the surface area by having a plurality of protuberances or fins. As shown in  FIG. 6 , the heat sinks  82  are respectively provided positions above the two coolers  80 , and are cooled by the coolers  80  through the heat transfer layer  78 . Note that the heat transfer layer  78 , upright wall member  81 , and heat sink  82  configure the “second member” in the present embodiment. 
         [0041]    As shown in  FIG. 5 , in the reagent refrigerator  10 , a cylindrical ventilation body  21   d  stands in the center of the first reagent container table  21 , and a forced air fan (fan unit)  88  is provided within the ventilation body  21   d . The forced air fan  88  is configured to blow the air taken in from above the ventilation body  21   d  downward in the ventilation body  21   d , the ventilation body  21   d  being the air flow pass. The airflow produced by the forced air fan  88  therefore blows on the heat transfer layer  78  that is directly cooled by the cooler  80 . The airflow is thus effectively cooled. 
         [0042]    The airflow produced by the forced air fan  88  flows outward in the radial direction after striking the heat transfer layer  78 , and changes direction upward after striking the upright wall member  81 , so that the air flows between the circumferential wall  64  (inside surface) of the reagent refrigerator  10  and the second reagent container table  22  and upward above the second reagent container table  22 . Thereafter, the air flows in an inward radial direction along the bottom surface of the cover  66 , and is taken into the top of the forced air body  21   d  so as to be once again blown downward by the forced air fan  88 , hence, circulating the air within the reagent refrigerator  10 . The reagent in the reagent container  300  placed in the first and second reagent container tables  21  and  22  is cooled to a desired temperature, for example, approximately 10° C., by the air circulated by the forced air fan  88 . 
         [0043]    Condensation is facilitated by the heat transfer layer  78 , upright wall member  81 , and heat sink  82  because the high thermal conductivity heat transfer layer  78 , upright wall member  81 , and heat sink  82  are exposed in the region below the top surfaces of the first and second reagent container tables  21  and  22  and the heat transfer layer  78 , upright wall member  81 , and heat sink  82  are cooled by the coolers  80 . On the other hand, condensation is inhibited mainly because the low thermal conductivity circumferential wall  64  (first member in the present invention) is arranged in the region above the top surfaces of the first and second reagent container tables  21  and  22 . 
         [0044]    Accordingly, condensation is produced solely below the top surface of the first and second reagent container tables  21  and  22  and condensation is inhibited above the top surface of the first and second reagent container tables  21  and  22  even though warm outside air flows into the housing  20  when the movable cover  68  of the cover  66  is opened and a reagent container  30  is set inside the housing  20 . Therefore, condensation water is prevented from adhering to the reagent container  300  even when the reagent container  300  comes into contact with the circumferential wall  64  while being set within the housing  20 . The problem of condensation water adhering to the reagent container  300  and, for example, the problems of condensation water penetrating into the reagent container  300  and adversely affecting the reading of the barcode adhered on the reagent container  300  are likewise avoided. 
         [0045]    The circumferential wall  64  is directly cooled by the upright wall member  81  which is cooled by the cooler  80  since the upright wall member  81  is arranged a distance from the inner surface of the circumferential wall  64  on the inner side of the circumferential wall  64  of the housing  20 . The circumferential wall  64  is therefore not overly cooled, and the formation of condensation on the circumferential wall  64  is inhibited. 
         [0046]    The upright wall member  81  is formed in a polygonal shape in plan view. As shown in  FIG. 8 , the airflow at the inner surface of the upright wall member  81  is directed toward a corner angle  81   b  of the upright wall member  81 , which changes the direction upward. Hence, the upright wall member  81  functions to direct the flow of the air upward. The air is effectively cooled since the airflow is within the entire inner surface of the upright wall member  81 , which is cooled by the cooler  80 . 
         [0047]    A cover heater  95  (refer to  FIG. 5 ) is provided inside the cover  66 , and the cover  66  is warmed by the cover heater  95 . Specifically, as shown in  FIGS. 3 and 5 , a channel  72 , which extends along the movement track of the arm  25   b  of the dispensing units  25  through  29 , is formed in the top surface of the cover  66 , and an aspirating hole  71  is formed in the channel  72 . The cover  66  becomes thin in the part of the channel  72 , and is therefore easily cooled by the cool air in the housing  20  so that external air readily condenses. Condensation formation is prevented in the channel  72  and penetration of condensation water into the housing  20  from the aspirating hole  71  is prevented by providing the cover heater  95  inside the cover  66  in the region of the channel  72 . 
         [0048]    As shown in  FIG. 5 , the first and second reagent container tables  21  and  22  are driven in rotation by the transport drive unit  13 . Specifically, the transport drive unit  13  has a first drive body  97  and a second drive body  98  configured by stepper motors or the like. The first and second drive bodies  97  and  98  are arranged at the side of the housing  20 , and are connected to the first and second reagent container tables  21  and  22  through a power transmission device  99 . The power transmission device  99  is configured by a first driven pulley  100 , second driven pulley  101 , first drive pulley  102 , second drive pulley  103 , first transmission belt  104 , and second transmission belt  105 . The first driven pulley  100  and the second driven pulley  101  are arranged on the center axis O of the reagent refrigerator  10 , and are supported by the bottom part of the housing  20  so as to be relatively mutually rotatable. The first reagent container table  21  is connected to the first driven pulley  100 , and the second reagent container table  22  is connected to the second driven pulley  101 . 
         [0049]    The first driven pulley  102  is mounted on the output shaft of the first drive body  97 , and the second drive pulley  103  is mounted on the output shaft of the second drive body  98 . The first drive belt  104  is reeved around the first driven pulley  100  and the first drive pulley  102 , and the second drive belt  105  is reeved around the second driven pulley  101  and the second drive pulley  103 . Therefore, the first reagent container table  21  can be rotated through the first drive pulley  102 , first transmission belt  104 , and first driven pulley  100  by operating the first drive body  97 ; the second reagent container table  22  can be rotated through the second drive pulley  103 , first transmission belt  105 , and second driven pulley  101  by operating the second drive body  98 . 
         [0050]    A first insertion opening  107  and a second insertion opening  108  are formed in the circumferential wall  64  of the housing  20  for the first drive transmission belt  104  and the second drive transmission belt  105  to pass through. At the side of the reagent refrigerator  10  is formed a chamber  109  to maintain airtightness and that is circumscribed by a heat insulating material; the receptacle  109  is connected to the reagent refrigerator  10  through the first insertion opening  107  and the second insertion opening  108 . Part of the drive shafts of the first and second drive bodies  97  and  98 , and the first and second drive pulleys  102  and  103 , the first and second transmission belts  104  and  105  are arranged in the chamber  109 . Therefore, since cool air is prevented within the chamber  109  even though the cool air within the housing  20  leaks from the first and second insertion openings  107  and  108 , there is no reduction in the cooling efficiency within the housing  20 . 
         [0051]    Since the first drive body  97  and the second drive body  98  are arranged at the side of the reagent refrigerator  10 , condensation does not adhere to the first drive body  97  and the second drive body  98  even when condensation water formed within the reagent refrigerator  10  spreads downward from the reagent refrigerator  10 , hence damage to the first drive body  97  and the second drive body  98  is prevented. 
         [0052]    Note that the first drive body  97  and the second drive body  98  are not limited to the side of the reagent refrigerator  10 , and may be arranged anywhere, even outside the reagent refrigerator  10 , with the exclusion of below the reagent refrigerator  10 . Although the power transmission device  99  is a transmission device employing drive belts reeved on pulleys, the present invention is not limited to this arrangement inasmuch as other drive transmission device also may be used, such as a gear transmission device. 
         [0053]      FIG. 7  is a side cross sectional view briefly showing the enlarged essential parts within the reagent refrigerator  10 . 
         [0054]    As shown in  FIG. 10 , the first reagent container table  21  has a first placement part  21   a  with a top surface  21   h  for setting a reagent container  300 , and a first support part  21   b  for supporting the first placement part  21   a  from the bottom side; the center part of the first support part  21   b  is connected to the first driven pulley  100  so as to be integratedly rotatable. A plurality of first openings  21   c  are formed with spacing in the circumferential direction from the center (region below the forced air fan  88 ) of the first support part  21   b , and air flows vertically through the first openings  21   c . The outer circumference end of the first support part  21   b  is positioned outside in the radial direction from the outer circumference end of the first placement part  21   a , and a concave step part  21   e  is formed in an approximate L-shape at the top surface side of the circumferential edge of the first reagent container table  21 . 
         [0055]    The second reagent container table  22  has a second placement part  22   a  with a top surface  22   h  for setting a reagent container  300 , and a second support part  22   b  for supporting the second placement part  22   a  from the bottom side; the center part of the second support part  22   b  is connected to the second driven pulley  101  so as to be integratedly rotatable. A plurality of second openings  22   c  are formed with spacing in the circumferential direction of the second support part  22   b , and air flows vertically through the second openings  22   c.    
         [0056]    Note that in the present embodiment, the first placement part  21   a  of the first reagent container table  21  is made of synthetic resin such as ABS or the like, and the second placement part  22   a  of the second reagent container table  22  is made of metal such as aluminum or the like. Alternatively, the first placement part  21   a  of the first reagent container table  21  may be made of metal, and the second placement part  22   a  of the second reagent container table  22  may be made of synthetic resin, or both may be made of synthetic resin or of metal. From the perspective of inhibiting formation of condensation, the placement parts  21   a  and  22   a  of the first and second reagent container tables  21  and  22  are most suitably both made of low conductivity synthetic resin. 
         [0057]    The outer peripheral edge of the first reagent container table  21 , that is, the outer circumferential edge of the first support part  22   b , is arranged to be outside in the radial direction from the inner peripheral edge of the second reagent container table  22 , that is, the inner circumferential edge of the second placement part  22   a . Thus, the outer peripheral edge of the first reagent container table  21  and the inner peripheral edge of the second reagent container table  22  overlap in a vertical direction so that no space occurs between the tables  21  and  22  in the plan view. The dimension of the overlap of the tables  21  and  22  is designated t. 
         [0058]    The outer peripheral edge of the first reagent container table  21  is arranged on the bottom side of the inner peripheral edge of the second reagent container table  22 . That is, when the airflow direction C below the first and second reagent container tables  21  and  22  is set as standard, the outer peripheral edge of the first reagent container table  21  positioned upstream of the airflow direction C is disposed below the inner peripheral edge of the second reagent container table  22  positioned on the downstream side. Therefore, the air flowing below the first and second reagent container tables  21  and  22  is unlikely to escape upward through the gap of the first and second reagent container tables  21  and  22 . Below the first and second reagent container tables  21  and  22 , an airflow can be reliably produced from the center of the housing  20  to the circumferential wall  64  of the housing  20 , thus suitably producing circulating air within the housing  20 . 
         [0059]    The inner peripheral edge of the second reagent container table  22  is arranged to fit into the step part  21   e  of the first reagent container table  21 , so that the top surface of the first reagent container table  21  and the top surface of the second reagent container table  22  are mutually at the same height. Thus, the heights of the reagent containers  300  of both reagent container tables  21  and  22  are the same, and the elevator strokes of the pipette  25   c  in the dispensing units  25  through  29  (refer to  FIG. 3 ) are uniform when aspirating reagent from the reagent container  300 . Operational control of the dispensing units  25  through  29  is therefore simplified. Moreover, there is no contact between the outer peripheral edge of the first reagent container table  21  and the inner peripheral edge of the second reagent container table  22 , and both tables  21  and  22  can rotate smoothly with little rotational friction even without a gap between the tables  21  and  22  in the plan view. 
         [0060]    As shown in  FIG. 6 , an annular first circumferential channel  135  is formed in the outer circumferential side of the heat transfer layer  78  provided on the bottom wall  63  of the housing  20 . The first circumferential channel  135  has the function of collecting condensation water formed by the heat transfer layer  78 . The first circumferential channel  135  is polygonal in shape (hexagonal in the example of the drawing) in plan view similar to the heat transfer layer  78 . A first drain hole  136  is formed in the bottom surface of the first circumferential channel  135 . 
         [0061]      FIG. 9  is a cross sectional view on the A-A arrow line in  FIG. 6 . The first drain hole  136  is connected to a first drain pipe  137 . The condensation water collected in the first circumferential channel  135  is discharged from the first drain hole  136  by periodically operating a pump (not shown in the drawing) that is connected to the first drain pipe  137 . 
         [0062]    As shown in  FIG. 6 , since the heat transfer layer  78  provided on the bottom wall  63  of the reagent refrigerator  10  is formed higher than the outer peripheral part in the outside radial direction, a second circumferential channel  110  is formed in the bottom surface of the outer circumferential part  77  between the heat transfer layer  78  and the circumferential wall  64 . The second circumferential channel  110  is positioned below the upright wall member  81 . Accordingly, the condensation water formed on the upright wall member  81  and the condensation water formed on the outer circumferential part of the heat transfer layer  78  is mainly collected in the second circumferential channel  110 . 
         [0063]    A second drain hole  121  and a third drain hole  131  are formed in the second circumferential channel  110 . As shown in  FIG. 9 , the third drain hole  131  is formed flush with the bottom surface (top surface of the outer circumferential part  77 ) of the second circumferential channel  110 , and a third drain pipe  132  is connected to the third drain hole  131 . The condensation water collected in the second circumferential channel  110  is discharge from the third drain hole  131  by periodically operating a pump (not shown in the drawing) connected to the third drain pipe  132 . 
         [0064]      FIG. 10  is a cross sectional view on the B-B arrow line in  FIG. 6 . A cylindrical preventer  123  is formed on the circumferential edge of the second drain hole  121 , and protrudes upward from the bottom surface of the second circumferential channel  110 . The preventer  123  has an apex height H that is lower than the top surface of the heat transfer layer  78 . The second drain hole  121  is connected to a third drain pipe  124 . When an amount of condensation water is collected in the second circumferential channel  110  that exceeds the preventer  123 , the condensation water overflows the preventer  123  and is naturally discharged from the second drain hole  121  to the outside. 
         [0065]    The present invention is not limited to the above embodiment and may be variously modified insofar as such modifications are within the scope of the claims. 
         [0066]    For example, although the forced air fan  88  generates an airflow that flows from top to bottom, an airflow also may be generated that flows from bottom to top. The flow of the air below the first and second reagent container tables  21  and  22  also may flow inward in the radial direction toward the center axis O of the circumferential wall  64  of the housing  20 . 
         [0067]    The upright wall member  81  also may be provided so as to contact the inner surface of the circumferential wall  64  of the housing  20 , and also may be detached from the heat transfer layer  78 . The upright wall member  81  also may be inclined so that the top part is positioned at the outside in the radial direction, thereby increasing the effect of changing the direction of the airflow. 
         [0068]    Although the first member of the present invention is configured by the circumferential wall  64  of the housing  20  of the reagent refrigerator  10  in the above embodiment, the first member may be configured by a low thermal conductivity member that is separate from the circumferential wall  64 , for example, a member arranged along the inner side of the circumferential wall  64 . In this case, the circumferential wall  64  may be formed of a high thermal conductivity material such as metal. It is preferable that the first member is configured by the circumferential wall  64  of the housing  20  as in the above embodiment because the first member reduces the space for placement of the reagent container  300  within the housing  20  when the first member is configured by a member that is separate from the circumferential wall  64 . 
         [0069]    The first member and the second member of the present invention are not limited to provision extending the entirety of the housing  20 , inasmuch as the first and second members also may be provided at intervals or provided intermittently. Particularly the first member also may be provided in a part allowing easy touching of the reagent container  300  when setting the reagent container  300  in the housing  20 . For example, as shown in  FIG. 4 , only the part of the circumferential wall  64  of the housing  200  that is exposed when the movable cover  68  of the cover  66  is opened may be formed of low thermal conductivity material, while the other parts (parts normally hidden by the cover  66 ) are formed of high thermal conductivity material. 
         [0070]    The first member and the second member of the present invention also may both be configured by the circumferential wall  64 . In this case, the part of the circumferential wall  64  above the top surface of the first and second reagent container tables  21  and  22  may be formed by a low thermally conductive material, and the part below the top surface of the first and second reagent container tables  21  and  22  may be formed of high thermally conductive material. 
         [0071]    The transport drive unit also may relatively rotate both reagent container tables  21  and  22  by rotating one or another of the first reagent container table  21  and the second reagent container table  22 .