Abstract:
A centrifugal separator having a cylindrical bottomed main rotor body, and a rack configured with a plurality of rack parts along the inner circumferential surface of the main rotor body, which rack parts are linked together and are able to move in radial directions of the main rotor body, so that when the main rotor body is rotated, the rack parts are pressed against the inner circumferential surface of the main rotor body and held there by the centrifugal forces associated with the rotating of the main rotor body.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a centrifugal separator, and particularly to a rotor structure. 
     2. Description of the Related Art 
     In the centrifugal separator  100  diagramed in FIG. 9, a motor  101  is installed via elastic bodies  103  to flanges  102   a  formed inside a frame  102 . To the drive shaft  104  of this motor  101 , a rotor  105  is engaged so as to be freely removable. 
     In this centrifugal separator, the rotor  105  is formed in a disc shape. On the upper surface periphery of the rotor  105  is formed an inclined surface  105   a  that is inclined toward the inside and downward. In this inclined surface  105   a , tube (test tube) insertion holes  106  are formed. 
     Now, a rotor  105  such as this is formed by machining an aluminum block or the like into a disc shape and then cutting the inclined surface  105   a , using a lathe or the like, and thereafter making the tube insertion holes  106  with a drill or the like. Accordingly, the machining becomes intricate and costly. Also, with such a rotor  105  as this, a certain thickness is required in the peripheral portion of the rotor  105  for forming the tube insertion holes  106 , resulting in increased weight. Accordingly, the motor  101  must have a sufficient capacity therefore, whereupon the centrifugal separator must be made large. In order to lighten the rotor  105 , the center portion of the rotor  105  (the portion where the drive shaft  104  of the motor  101  is attached) and portions other than those portions needed for forming the tube insertion holes  106 , indicated by the double-dotted lines in FIG. 9, can be cut away, but that results in the shape of the rotor  105  becoming complex and machining that is much more intricate. Furthermore, in order to accommodate other types of tubes having different diameters, other rotors  105  must be made available that are provided with tube insertion holes  106  having diameters corresponding to those other tubes, resulting in escalating costs. 
     In a centrifugal separator  110  diagramed in FIG. 10, a rotor  111  is configured by a main rotor body  112  provided with a plurality of holes  112   a  in the upper surface periphery of a disc, and cubical racks  113  loaded in the main rotor body  112 . With this rotor  111 , the main rotor body  112  is engaged to the drive shaft  104  of the motor  101 , and the racks  113  are accommodated, respectively, in the holes  112   a  in that main rotor body 
     With such a rotor  111  as this, in order to prevent the weight from being displaced to one side, the multiple racks  113  must be accommodated respectively in the holes  112   a  of the main rotor body  112  symmetrically about the center of the drive shaft  104  to achieve balance. Since the operation of accommodating these racks  113  in the main rotor body  112  is intricate, and each of the racks  113  is formed independently, not all that many tube insertion holes (not shown) can be formed in the upper surface of the racks  113 . 
     SUMMARY OF THE INVENTION 
     Thereupon, an object of the present invention is to provide a centrifugal separator rotor that is both lightweight and easy to machine. 
     Another object of the present invention is to provide a centrifugal separator rotor wherewith the rack loading operation is simple, and the number of tube insertion holes can be increased. 
     Yet another object of the present invention is to provide a centrifugal separator rotor that can easily and inexpensively be made to accommodate various tube types. 
     In order to achieve the objects stated above, the centrifugal separator of the preset invention comprises: a cylindrical bottomed main rotor body; and a rack configured with a plurality of rack parts along the inner circumferential surface of the main rotor body, the rack parts of which are linked together and are able to move in radial directions of the main rotor body; wherein: when the main rotor body is being turned, the rack parts are pressed against the inner circumferential surface of the main rotor body and held there by the centrifugal forces associate with the turning of the main rotor body. 
     As based on the centrifugal separator of this invention, the rotor is made up of the main rotor body and the rack, respectively, as separate parts, wherefore the shape thereof can be simplified and machining made easy. 
     More specifically, because the main rotor body of the centrifugal separator of this invention can be a shape that stops the rack on the inner circumferential surface thereof, the main rotor body may have the simple structure of a bottomed cylinder, whereby the rotor can be made lighter in weight and less costly. It is also possible to form the rack of lightweight parts of plastic or the like, which not only facilitates cost reduction but also makes it possible to make the motor, etc., smaller, and thus to make the centrifugal separator both smaller and lighter in weight. Furthermore, when tubes are loaded into the rotor, the tubes can be loaded into a rack at another location beforehand and that rack then can be accommodated in the main rotor body. Thus, work efficiency is improved because only the lightweight rack need be moved, and tubes can be loaded into racks at other locations. 
     In a centrifugal separator of the present invention, moreover, a disc Is provided which fits tightly and integrally to the main rotor body at the center part thereof, and the multiple rack parts are linked together via the circumferential edge of the disc. 
     With the centrifugal separator of this invention, after mounting the rack parts about the circumferential edge of the disc, the disc is fit tightly on to the center part of the main rotor body. In this condition, when the main rotor body is driven so that it turns, the rack parts move out in radial directions due to centrifugal force, and are stopped when they come up against the inner circumferential surface of the main rotor body. 
     That is, with the centrifugal separator of this invention, the disc need only position the rack, and-need not have the strength required to hold the rack. Also, the rack is stopped by the inner circumferential surface of the main rotor body, due to the centrifugal force generated when the main rotor body is driven so that it turns, wherefore it is only necessary that the main rotor body retain sufficient strength, and thus the rotor can be made lighter. 
     In centrifuge operations, moreover, tubes are loaded into a rack at a different location beforehand, so that it is only necessary to mount the disc on which do racks have been mounted to the main rotor body. That is, only lightweight racks need be carried about, which makes the work easier. 
     In a centrifugal separator of the present invention, further more, a hub is erected in the center of the main rotor body. Splines are formed which extend upward and downward on the outer circumferential surface of the hub, and a spline hole is formed in the center of the disc. By pushing the spline hole of the disc down onto the splines of the main rotor body, the disc is made to fit tightly on the main rotor body. 
     With the centrifugal separator of this invention, the disc can be made to fit tightly to the main rotor body by pushing the center of the disc down onto the hub erected in the center of the main rotor body, wherefore the operation of mounting a rack on the main rotor body is extremely simple. 
     In a centrifugal separator of the present invention, moreover, grooves are formed in the inner circumferential surface of the rack parts. These grooves are made to mate with the circumferential edge of the disc, and, at the same time, the rack parts are mounted to the disc by pins inserted into the rack parts and the disc. 
     With the centrifugal separator of this invention, rack grooves are mated with the circumferential edge of the disc and the rack parts are held by the disc, wherefore the rack parts are securely held by the disc. 
     In a centrifugal separator of the present invention, furthermore, the rack is formed in a ring shape. At multiple locations in this rack, one slit is formed in a radial direction so as to completely cut and separate the rack, and slits are made in radial directions which cut the rack while leaving a portion of the inner circumferential edge thereof. The rack parts are formed by these slits so that they are divided. 
     As based on the centrifugal separator of this invention, the rotor is fabricated by a main rotor body and a rack, respectively, as separate parts, wherefore the shape is simplified and machining is made easy. 
     More specifically, the main rotor body need only be of a shape that will stop the rack with the inner circumferential surface thereof, wherefore the main rotor body can have the simple structure of a bottomed cylinder, and hence the rotor can be made lighter in weight and less costly. It is also possible to form the rack of lightweight parts made of plastic or the like, as a consequence costs can be reduced, the motor made smaller, and the centrifugal separator made both smaller and lighter in weight. Furthermore, when loading tubes into the rotor, the tubes can be loaded beforehand into a rack at a different location and then that rack accommodated in the main rotor body, so that it is only necessary to move the lightweight racks, making the work easier and enhancing work efficiency. 
     With the centrifugal separator of this invention, furthermore, the rack parts are formed integrally so that they do not separate, wherefore the number of tube insertion holes can be increased. In order to accommodate different types of tubes, moreover, it is only necessary to have racks that conform to the different tube types, using the same main rotor body in common, wherefore costs can be kept low. 
     In a centrifugal separator of the present invention, moreover, either projections or concavities are formed in the main rotor body while concavities or projections, respectively, are formed in the rack, so that the rack can be engaged with the main rotor body by those projections or concavities, such that the rack will be restricted to the same direction of turning as the main rotor body. 
     As based on the centrifugal separator of this invention, the engagement between the main rotor body and the rack can be implemented in a simple configuration, making it easy to mount the rack on the main rotor body. 
     In a centrifugal separator of the present invention, furthermore, the rack is configured with a ring-shaped main rack that is accommodated inside the main rotor body and auxiliary racks that accommodate pluralities of tubes, and auxiliary rack accommodation holes that are formed about the entire circumference of the main rack. 
     As based on the centrifugal separator of this invention, tubes are accommodated in tube-holding holes in the auxiliary racks, those racks are accommodated beforehand in the auxiliary rack accommodation holes in the main rack, and that [main rack] is accommodated inside the main rotor body. Accordingly, if auxiliary racks are provided which have tube-holding holes corresponding to different types of tubes, the main rack body and the main rack can be used commonly and costs reduced accordingly. 
     In a centrifugal separator of the present invention, moreover, projections or concavities are formed on the upper surface of one rack while concavities or projections, respectively, are formed in the lower surface of another rack, the other rack is mounted on the first rack, and the concavities or projections in the other rack in the upper stage are mated with the projections or concavities, respectively, in the first rack in the lower stage, thereby restricting the other rack in the upper stage to the same turning direction as the first rack in the lower stage. 
     With the centrifugal separator of this invention, the rack in the upper stage is restricted to the same circumferential direction as the rack in the lower stage by mating the concavities or projections in the rack in the upper stage with the projections or concavities, respectively, of the rack in the lower stage, thus making it possible to simultaneously centrifuge tubes accommodated in multiple stages of racks. This is very efficient, and makes it possible to simultaneously perform centrifuge operations on racks of different types, and, hence, on tubes of different types. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded diagonal view of an aspect of one embodiment of a centrifugal separator relating to the present invention; 
     FIG. 2 is an enlarged cross-sectional view of the main parts of the rotor diagramed in FIG. 1, showing how they are assembled; 
     FIG. 3 is a cross-sectional view showing how the racks diagramed in FIG. 1 are assembled in multiple, stages in the main rotor body; 
     FIG. 4 is an exploded diagonal view of an aspect of another embodiment of a rotor in a centrifugal separator relating to the present invention; 
     FIG. 5 is a plan of a rack in the rotor diagramed in FIG. 4; 
     FIG. 6 is a cross-sectional view showing how the rotor diagramed in FIG. 4 is assembled; 
     FIG. 7 is a cross-sectional view of an example modification of the rotor diagramed in FIG. 4, showing how the rotor is assembled; 
     FIG. 8 is a cross-sectional view of another example modification of the rotor diagramed in FIG. 4, showing how the rotor is assembled; 
     FIG. 9 is a conceptual cross-sectional view of a centrifugal separator comprising a conventional rotor; and 
     FIG. 10 is a conceptual cross-sectional view of a centrifugal separator comprising another conventional rotor. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An aspect of one embodiment of a rotor in a centrifugal separator relating to the present invention is represented in FIGS. 1 to  3 . 
     A rotor  20  in this centrifugal separator is configured by a main rotor body  21 , a disc  22 , and a rack  23 , etc. 
     The main rotor body  21  is shaped as a bottomed cylinder, provided with a hub  24  in the center thereof protruding toward the inside. Splines  25  are formed about the circumferential surface of this hub  24 , parallel to the axial centerline thereof. In the hub  24  a hole  26  is formed that opens at the lower surface of the bottom wall  21   a  of the main rotor body  21 , as diagramed in FIG. 2, and a hexagonal concavity  27  is formed in the circumferential surface at the opening of that hole  26 . In the hub  24 , moreover, a bolt insertion hole  28  is formed that allows the hole  26  to penetrate to the upper surface. 
     To a motor drive shaft  1   a , meanwhile, a hexagonal convexity  2  is formed, about the circumference thereof, as diagramed in FIG.  1 . 
     Then, as diagramed in FIG. 2, when the hole  26  in the main rotor body  21  is mated to the motor drive shaft  1   a , the concavity  27  fits down over the convexity  2  in the motor drive shaft  1   a . Next, a bolt  4  is inserted from the bolt insertion hole  28  in the main rotor body  21 , the tip thereof is screwed into the female-threaded hole  3  in the drive shaft  1   a , and the main rotor body  21  is thus coupled to the motor drive shaft  1   a . Accordingly, the main rotor body  21  has its turning relative to the motor drive shaft  1   a  restricted by the engagement between the concavity  27  and the convexity  2  in the motor drive shaft  1   a.    
     The disc  22  has, in the center thereof, a spline hole  29  corresponding to the splines  25  in the hub  24 , and also has four sets of long holes  30  about the circumferential edge thereof. In each set of long holes  30 , two holes are formed within the range of a quarter circle ([at angles of] 45° with the center). These long holes  30  are formed so that they are mutually parallel. 
     The turning of this disc  22  relative to the main rotor body  21  is restricted by the mating of this spline hole  29  with the spines  25  in the hub  24  of the main rotor body  21 . 
     The rack  23  is configured by combining together four rack parts  23   a  formed by cutting a doughnut ring shape roughly into quarters. Each rack part  23   a  is formed in a circular arc that forms roughly a quarter circle. In the inner circumferential surface of each of these circular-arc shaped rack parts  23   a  is formed an arc-shaped groove  31  that is open at that inner circumferential surface. In the upper and lower lip pieces  32  and  33  that define that groove  31  two holes  34  are formed that penetrate those pieces. These holes  34  are formed at positions corresponding to the long holes  30  in the disc  22 . 
     The rack parts  23   a  have inclined surfaces  35  formed on the upper surface thereof so that they face inward. In each inclined surface  35  are formed six tube accommodation holes  36 . 
     This rack part  23   a  is manipulated so that the groove  31  therein is mated with the circumferential edge of the disc  22 , the holes  34  in the rack part  23   a  are matched with the holes  30  of the disc  22 , and spring pins  37  are inserted into those holes  34  and  30 , thus holding the rack part  23   a  to the disc  22 . Each rack part  23   a  held to the disc  22  in this manner can move in the radial direction of the disc  22  because the pins  37  can move within the long holes  30  in the disc  22 . 
     In a centrifugal separator rotor  20  configured in this way, the rack parts  23   a  are mounted by mating their grooves  31 , respectively, with the circumferential edge of the disc  22 , and spring pins  37  are inserted respectively into the holes  34  in the rack parts  23   a  and into the long holes  30  in the disc  22  to hold the rack parts  23   a  to the circumferential edge of the disc  22 . Then, after loading tubes A into the holes  36  in the rack  23  configured in this manner by assembling the rack parts  23  in a ring shape, the spline hole  29  of the disc  22  is mated to the splines  25  of the hub  24  of the main rotor body  21 . Repeating this operation, racks  23  are sequentially stacked in upper stages, as diagramed in FIG.  3 . 
     In FIG. 3, moreover, in this centrifugal separator, a motor  1  having the drive shaft  1   a  is mounted to flanges  6 ( a ) of a frame  6  via elastic bodies  5 . In the upper part of the frame  6 , an inner case  7  is deployed so that it encloses the rotor  20 . A cooling line  8  is wound about the outer circumferential surface of the inner case  7 . An outer case  9  is deployed about the periphery of the inner case  7 , and the space between the outer case  9  and inner case  7  is filled with thermal insulation  10 . One end of the cooling line  8  is passed through a compressor  11 , condenser  12 , and capillary tube  13  and connected to the other end of the cooling line  8  thereby configuring a cooling system. 
     When the rack  23  has been set in the main rotor body  21  in this way, if the rotor  20  is not being turned, a slight gap is opened between the outer circumferential surface of the rack parts  23   a  and the inner circumferential surface of the main rotor body  21 , as diagramed in FIG.  2  and FIG.  3 . Then, when the main rotor body  21  is driven so that it turns, centrifugal forces operate on the rack parts  23   a , the spring pins  37  in the rack parts  23   a  move outward in radial directions along the long holes  30  in the disc  22 , and, as a consequence, each rack part  23   a  comes up against and is stopped by the inner circumferential surface of the main rotor body  21 . 
     That is, with the rotor  20  of this invention, the centrifugal forces that develop in the rack parts  23   a  are stopped by the inner circumferential surface of the main rotor body  21 , wherefore the disc  22  need only position the rack parts  23   a , and need not have strength sufficient to securely hold the rack  23 . Accordingly, by forming the disc  22  of something having a thin wall thickness and forming the rack parts  23   a  with the minimum capacity required for inserting the tubes A, the rotor  20  can be made lightweight. 
     In the embodiment aspect described in the foregoing, the rack parts  23   a  are mounted to the disc  22  with spring pins  37 , but it is also permissible, for example, to form female threads in the holes  34  in the lip  33  in the rack parts  23   a  and use screws instead of the spring pins  37 , whereupon the screws may be inserted into the holes  34  in the lips  32  of the rack pieces  23   a  and the long holes  30  in the disc and their tips screwed into the holes  34  in the lip  33 . In other words, if the rack parts  23   a  are deployed along the inner circumferential surface of the main rotor body  21 , and the circumferential direction thereof is restricted relative to the main rotor body  21 , so that, when centrifugal forces act on the rack parts  23   a , the rack parts  23   a  can move outward in radial directions so that they come up against the inner circumferential surface of the main rotor body  21  due to those centrifugal forces, that is sufficient to hold the racks in place. 
     With the embodiment aspect described in the foregoing, moreover, a disc  22  is used, and the arc-shaped rack parts  23   a  are coupled to the circumferential edge of the disc  22  to configure a ring-shaped rack  23 , but it is permissible to mutually couple the side surfaces of adjacent rack parts  23   a  to assemble them into a ring shape, and to position these along the inner circumferential surface of the main rotor body  21 , without using a disc  22 . In that case, it is desirable that adjacent rack parts  23   a  be coupled so that the rack parts  23   a , respectively, can independently move outward in radial directions so that they come up against the inner circumferential surface of the main rotor body  21 . It is also desirable that the rack  23  have its circumferential direction restricted relative to the main rotor body  21  by such means as stoppers. 
     An aspect of another embodiment of a rotor in a centrifugal separator relating to the present invention is represented in FIGS. 4 to  6 . 
     A rotor  40  in this centrifugal separator is configured by a main rotor body  41  and a rack  42 . 
     The main rotor body  41  is shaped as a bottomed cylinder, provided with a hub  43  protruding in the center toward the inside. In this hub  43  a concavity  44  is formed, from the lower surface of the bottom wall  41   a  of the main rotor body  41 , as diagramed in FIG. 6, and a cut-out  45  is made in the opening in this concavity  44  extending in a radial direction. Then, when the concavity  44  in the main rotor body  41  is mated with the motor drive shaft  1   a , the cut-out  45  mates with a pin  46  implanted in the motor drive shaft  1   a , and the turning of the main rotor body  41  relative to the motor drive shaft  1   a  is restricted. In addition, positioning pins  47  are erected in the upper surface of the bottom wall  41   a  of the main rotor body  41 . 
     The rack  42  forms a ring, and inclined tube holding holes  48  are formed about the entire circumference in the inner circumferential surface thereof. Also, as diagramed in FIG. 5, a slit  49  is formed in this rack  42 , at one location in the circumferential direction thereof, to completely separate the rack  42  in a radial direction, and slits  50  are also formed at two more locations therein, having cuts made therein which leave the inner circumferential portion of the circumferential edge. The rack  42  is thus delineated by these slits  49  and  50  into a plurality of rack parts  42   a  (three parts in the diagram). Also, as diagramed in FIG. 6, holes  51  are formed in the bottom surface of the rack  42  so that, by mating these holes  51  with the positioning pins  47  in the main rotor body  41 , the turning of the rack  42  relative to the main rotor body  41  is restricted. The holes  51  are formed slightly larger than the diameters of the pins  47  to permit movement of the rack parts  42   a  outward in radial directions due to the centrifugal forces described below. 
     With a centrifugal separator configured in this way, the concavity  44  in the main rotor body  41  is mated with the motor drive shaft  1   a , the cut-out  45  therein is mated with the pin  46  in the motor drive shaft  1   a , and the turning of the main rotor body  41  relative to the motor drive shaft  1   a  is restricted. Also, the holes  51  in the rack  42  are mated with the pins  47  in the main rotor body  41 , and the rack  42  is restricted to the same turning direction as the main rotor body  41 . Either before or after setting the rack  42  in the main rotor body  41 , the tubes (not shown) are loaded in the rack  42 . Then the motor  1  is driven. Thereupon, centrifugal force develops in each of the rack parts  42   a  in the rack  42 , and each rack part  42   a  opens out in the direction of the ring-shaped circumferential wall of the main rotor body  41  and comes up against that circumferential wall  41   b . The rack parts  42   a  are therefore held stable in the main rotor body  41 . 
     In the aspect of the embodiment described in the foregoing, furthermore, the tube holding holes  48  are formed facing downward, but, in the centrifugal separator of the present invention, these holes  48  may of course be formed in either vertical or horizontal directions. 
     In the aspect of the embodiment described in the foregoing, moreover, the holes  51  formed in the rack parts  42   a  may have a circular cross-section or an elliptical cross-section. 
     In the aspect of the embodiment described in the foregoing, furthermore, pins  47  are erected in the main rotor body  41  and holes  51  corresponding to those pins  47  are formed in the rack parts  42   a , but it is also permissible to form projections having some other shape than the pins  47  in the main rotor body  41  to form concavities corresponding to those projections in the rack parts  42   a , or, conversely, to form concavities in the main rotor body  41  and form projections in the rack parts  42   a.    
     In the aspect of the embodiment described in the foregoing, moreover, the pins (projections)  47  are formed on the upper surface of the bottom wall  41   a  of the main rotor body  41 , and the holes (concavities)  51  are formed on the lower surface of the rack parts  42   a , but those may be formed in the circumferential wall of the main rotor body  41  and the circumferential walls of the rack parts  42   a.    
     In the centrifugal separator diagramed in FIG. 6 also, as in the centrifugal separator diagramed in FIG. 3, a motor  1  having a drive shaft  1   a  is mounted on flanges  6 ( a ) in a frame  6  via elastic bodies  5 . In addition, an inner case  7  is deployed in the upper part of the frame  6  so as to enclose the rotor  40 , and a cooling line  8  is wound about the outer circumferential surface of that inner case  7 . An outer case  9  is also deployed about the periphery of the inner case  7 , and the space between the outer case  9  and inner case  7  is filled with thermal insulation  10 . One end of the cooling line  8  is passed through a compressor  11 , condenser  12 , and capillary tube  13  and connected to the other end of the cooling line  8  to configure a cooling system. 
     In FIG. 7, another modification example of the rotor diagramed in FIGS. 4 to  6  is diagramed. This modification example is configured so that the rack diagramed in FIGS. 4 to  6  is mounted in two stages in the main rotor body. 
     In this embodiment aspect, the rotor  60  is basically the same as the rotor  40  described above, but, inside a main rotor body  61 , in order to accommodate racks  62  and  63  in two stages, the side wall  61   a  is formed higher than the side wall in the main rotor body  41  in the embodiment aspect described above, and pins  64  are implanted in the upper surface of the rack  62  in the lower stage. 
     The structure of the parts other than the main rotor body  61  in the rotor  60  are the same as diagramed in FIGS. 4 to  6 , and the shapes and positions of the pins  65  are the same as for the pins  47  described earlier. The parts other than the racks  62  and  63 , such, for example, as the overall shape of the rack  42 , and the positions and shapes of the slits  49  and  50 , etc., in the aspect of the embodiment diagramed in FIGS. 4 to  6 , are formed similarly. The holes  66  and  67  formed in the racks  62  and  63 , and the tube holding holes  68  and  69 , are also no different, in terms of shape and position, than the holes  51  and  48  in the rack  42  described earlier. 
     In this modification example, furthermore, in activating the rotor  60 , tubes A are loaded in the tube holding holes  68  in the lower-stage rack  62 , the holes  66  in that lower-stage rack  62  are mated with the pins  65  in the main rotor body  61 , and the rack  62  is loaded in the main rotor body  61 . Similarly, tubes A are loaded in the tube holding holes  69  in the upper-stage rack  63 , the holes  67  in that upper-stage rack  63  are mated with the pins  64  in the lower-stage rack  62 , and the rack  63  is mounted on the lower-stage rack  62  and thus loaded in the main rotor body  61 . 
     In FIG. 8 is diagramed a modification example of the rotor diagramed in FIGS. 4 to  6 . This modification example is also configured by a main rotor body  71  and a rack  72 , as in the embodiment aspects described earlier. The main rotor body  71  is shaped as a bottomed cylinder, as is the main rotor body  41  in an embodiment aspect described earlier, and pins  73  are erected on the upper surface of a bottom wall  71   a.    
     The rack  72 , however, is configured by a main rack  72   a  and auxiliary racks  72   b . The main rack  72   a  forms a ring as does the rack  42  in the embodiment aspect described earlier. On the inner circumferential surface thereof, multiple auxiliary rack accommodation holes  74  are formed about the entire circumference, which are inclined, and holes  75  are formed in the lower surface thereof. The auxiliary racks  72   b  each have a plurality of tube holding holes  76  for accommodating tubes A. 
     Then, when activating the rotor  70 , tubes A are loaded in the tube holding holes  76  in the auxiliary racks  72   b , those auxiliary racks  72   b  are loaded in the auxiliary rack accommodation holes  74  in the main rack  72   a , the holes  75  in that main rack  72   a  are mated with the pins  73  in the main rotor body  71 , and the main rack  72   a  is thus loaded in the main rotor body  71 . 
     The positions and shapes, etc., of the parts other than the main rack  72   a  in the rotor  70  are formed in the same way as the overall shape of the rack  42  and the positions and shapes, etc., of the slits  49  and  50  in the embodiment aspects described earlier, and there are no differences in the functions thereof. The main rotor body  71  is the same, moreover, as the main rotor body  41  in the embodiment aspect described earlier.