DE10017904A1 - Rapid automatic loader for swing-rotor centrifuge separating e.g. blood plasma for analysis includes system dispensing fluid into reservoir for perfect balancing - Google Patents

Abstract

A rack holder (30) can be attached to the reception pocket of the centrifuge swinging hanger. The rack holder includes balancing fluid reservoirs (32). Loading of the centrifuge, comprising the total weight of: the rack (15) for small sample tubes, their varied contents, the rack holder (30) and fluid contained in the rack holder reservoir, is maintained sensibly constant. An Independent claim is included for the method of loading and unloading the centrifuge. The rack, filled with sample tubes, is introduced into the centrifuge by a supply unit. The rack is grasped by the handling robot. Weight of the rack is determined using the weigher (16) of the handling robot. A determined quantity of fluid is supplied into the dosing reservoir (17) of the handling robot. The rack is inserted into the rack holder in the centrifuge hanger. The set quantity of fluid is transferred into the rack holder reservoirs (32), achieving the required constant total weight. Centrifugation proceeds. The robot sucks fluid from the rack holder reservoir. It unloads the rack from the centrifuge hanger. A removal unit takes the rack from the centrifuge.

Description

The invention relates to a device and a method for loading and unloading a Centrifuge according to the preamble of the independent claims.

Such a device for loading and unloading a centrifuge is for example with the patent US 5,769,775, which has a swing-bucket rotor has several on its rotationally symmetrical arms Has centrifuge hangers with at least one storage compartment each. In this The receiving compartment is at least one that can be equipped with several sample tubes Sample tube rack added, one for weight determination Weighing device and a handling device for handling the sample tube rack Robot is available, which has a gripper that can be moved in two axes.  

Such centrifuges are generally used to measure the components of the liquids in the sample tubes, such as e.g. B. blood from each other separate. So blood plasma from the blood cells can be used for a subsequent one Analysis to be separated.

With this centrifuge, the weight of the centrifuge is first incoming sample tube racks are determined in a weighing device, and then the sample tube racks are moved in using a handling robot the centrifuge inserted itself.

This insertion of the sample tube racks does not take place one after the other following or about randomly, but takes over the control of the handling robot the task of inserting the sample tube racks into the centrifuge in such a way that the centrifuge is optimally balanced. Here is a run through complicated calculation algorithm several times.

The disadvantage here is that on the one hand all sample tube racks individually must be weighed, then according to the calculation algorithm in the centrifuge be introduced and accordingly additional empty inserts or Replacement weights (dummies) can be used for optimal balancing have to.

On the one hand, this requires more time to load the centrifuge, secondly, dummies or empty bets must be made available. This means that the space in the centrifuge is not complete for too centrifuging sample tube is used, and also the balancing will never be optimal, what with increased wear of the swing-bucket rotor connected is. This results in increased acquisition and operating costs.

Such automatic centrifuges are used more and more often because the Samples are increasingly processed centrally, the findings of the analyzes always  must be available more quickly, the cost per sample must be reduced and the risk of infection and injury to laboratory personnel is minimized have to.

The object of the present invention is now a device and a method the genus mentioned in such a way that a simpler and faster, automated loading of the centrifuge is made possible and the Acquisition and operating costs of such a centrifuge can be reduced.

The technical teaching of independent claims.

An essential feature here is that the A rack holder can be attached to the centrifuge hanger, which rack holder has at least one fluid reservoir in which a fluid for balancing the centrifuge can be accommodated, so that the total weight of the Sample tube rack with sample tube, the rack holder and the fluid within the fluid reservoir of the rack holder different samples for one Loading of the centrifuge is essentially constant.

The advantage here is that the possibility of optimally balancing the Centrifuge it is now possible for the first time to reduce the size of the centrifuge bearings dimension and by fully loading the centrifuge without complex Calculation algorithms and without the use of replacement weights as a dummy or as empty inserts, each with a predetermined weight, the manufacturing and Reduce operating costs for the centrifuge significantly.

In addition, the centrifuge can be filled by filling the fluid reservoir of the rack Holders with a liquid can be loaded faster and easier as one unnecessary additional handling of replacement weights by the robot is eliminated can.  

In addition, a rack holder once filled with liquid only needs in minor filling or pumping out a minor Amount of liquid for optimized balancing, which saves additional time brings with it.

To further simplify the construction and use of existing ones Institutions may also have only one common Device for loading and unloading used for two or more centrifuges becomes. The shared facility for loading and unloading is then alternately back and forth between the centrifuges and as straight as possible then load or unload a centrifuge, if one or more others Centrifuges are in proper operation, i.e. centrifuge.

In one embodiment of the invention it is provided that the handling of the Rack holder also by the handling robot for the sample tube racks is accomplished. Thus, unnecessary costs and space within the Centrifuge saved for a second robot and its control devices and a time-consuming and costly installation and removal of the rack holder in the centrifuge hangers are no longer needed by hand.

In another embodiment of the invention, however, it is provided that the Handling of the rack holder and / or the sample tube rack by a second one Handling robots happen, which gives another significant time advantage becomes. Simultaneously with picking up or putting down a sample tube rack by means of the first handling robot, the second handling Robot already has a second sample tube rack or a rack holder Pick Up, Procedure or Filing. This is a "two-handed operation" possible, similar to the loading of the centrifuge by a human.

The rack holders have a counterweight to hold liquid at least one, but preferably several fluid reservoirs, these  then connected to each other via connections to communicating vessels are. This also enables an optimized weight distribution within the rack Holder take place automatically and thereby balancing the entire Centrifuge to be improved.

For the optimized balancing of the centrifuge, it is preferred that Fluid reservoirs mirror-symmetrical to the longitudinal axis and / or to the transverse axis and / or to arrange the vertical axis of the rack holder.

The connections of the fluid reservoirs of the preferably made of plastic Rack holders are directly cast or injected with one another, or in the form of through holes and Connection channels provided. These are connections of the fluid reservoirs preferably in the bottom of the rack holder at the lowest point of the Fluid reservoirs are provided so that a liquid balance even at low Level between the fluid reservoirs is possible.

The fluid reservoirs are preferably designed to be open at the top and are then filled or emptied from above, which has the advantage that no liquid is accidentally when coupling with the connecting hoses of the higher-level dosing reservoir can be spilled, what that Balancing the centrifuge would affect.

The weighing device and / or the dosing reservoir for the rack holder are included either upstream of the handling robot or in the handling robot integrated. Integrating the weighing device or the dosing reservoir into the Handling robot has the advantage that at the same time as placing the Sample tube racks a weight determination and / or the addition of Liquid can be used for balancing. In turn, the loading time the centrifuge can be shortened considerably, even if this means a more expensive, constructive effort is connected.  

For a suitable weight determination, the weighing device or the Dosing reservoir on or between the pair of pliers of the gripper of the handling Robot attached.

It can also be provided that the weighing device or the dosing reservoir within at least one of the tongs of the handling robot's gripper itself is introduced, which leads to a further improvement in the loading speed and leads to more exact weight determination and thus to an improved Balancing, even if this affects the volume of the dosing reservoir.

The specific characteristics of the gripper are:

• - acid and corrosion resistance;
• - Safe clamping force, especially through a pneumatic control;
• - High flexibility through the use of different gripper fingers.

With regard to the method for loading and unloading the centrifuge according to the invention described above, the following routes can be followed:
A preferred method of the present invention provides the following method steps:

• a) Introducing at least partially filled with sample tubes Sample tube racks via the feed unit into the centrifuge;
• b) grasping the sample tube racks using the handling robot;
• c) Weight determination of the sample tube racks using the weighing device the handling robot;  
• d) feeding the determined amount of fluid into the dosing reservoir of the handling Robots;
• e) inserting the sample tube racks into the rack holders in the centrifuge hanger;
• f) supplying the determined amount of fluid from the dosing reservoir of the Handling robots in the fluid reservoirs of the rack holder to do that Total weight of the sample tube rack with the sample tube, the rack holder and the fluid within the fluid reservoir of the rack holder to keep essentially constant;
• g) centrifugation;
• h) Sucking the fluid out of the fluid reservoirs using the handling robot the rack holder;
• i) Unloading the sample tube racks from the centrifuge suspension using the Handling robots;
• j) Removing the sample tube racks via the removal unit from the centrifuge.

The weight determination of the sample tube racks according to the Process step c) of the preferred process mentioned above can also be carried out in another procedure via the weighing device outside of the handling Robot be provided before step b), rather than on the Weighing device of the handling robot.

A combination of both weight determination principles should also be through the Invention to be covered. So z. B. a first weight determination before The robot grabs the sample tube racks using the first Weighing device carried out outside the handling robot, by means of which  e.g. B. the dosing reservoir is filled. This is then followed by grasping the Sample tube racks by the robot using a second weight determination the weighing device of the handling robot, by means of which the filling of the Fluid reservoirs of the rack holder takes place. This allows the throughput through the Centrifuge can be increased.

Process step d) of the above-mentioned processes, namely the feeding of the determined amount of fluid in the dosing reservoir of the handling robot, can can also be replaced by supplying fluid into the dosing reservoir of the Handling robot until it contains at least the determined amount of fluid, which leads to shorter filling times. This can also be done with very large dosing reservoirs Process step d) is completely omitted, or only rarely, for. B. once a day.

A development of the method provides that step h) of the above cited preferred method completely eliminated, so that after Centrifuge no suction of the fluid from the fluid reservoirs of the rack Holder is performed. The fluid therefore remains until the next Weight determination in the fluid reservoirs, so that then depending on the weight only introduced a small amount of fluid according to process step f) or must be suctioned off.

This frees the robot for loading the centrifuge suspension with the next batch of racks. For reasons of hygiene, the fluid is after a completely sucked out of the fluid reservoirs for a certain period of use, for example once a day.

The suction of the fluid by means of the handling robot Fluid reservoirs of the rack holder according to method step h) or the Modified process step f) can take place in a drain or in Cycle are performed so that the extracted fluid back into the  Dosing reservoir is returned. Also a combination of drainage and Circulation is to be covered by the invention.

In the following, the invention will be explained using only one embodiment illustrative drawings explained in more detail. Here go from the drawings and their description further features and advantages of the invention.

Show it:

Figure 1 shows the rack holder according to the invention in front view in section along the line II in Fig. 2.

FIG. 2 shows the inventive rack holder according to Figure 1 in plan view.

FIG. 3 shows the inventive rack holder according to Fig 1 in a side view in section along the line III-III.

Fig. 4 is a centrifuge suspension by the arms of a swing-a centrifuge in front view;

Fig. 5, the centrifuge suspension according to Fig 4 in a side view.

Fig. 6 shows an embodiment of the handling robot according to the invention in perspective view;

Fig. 7 is a perspective view of a centrifuge with the loading and unloading device according to the invention.

FIG. 7 shows a perspective illustration of a centrifuge 1 with the loading and unloading device according to the invention, the loading and unloading device according to the invention being introduced within a centrifuge 1 known per se.

This centrifuge 1 now consists of a feed unit 3 , which conveys sample tube racks 15 into the centrifuge 1 in the feed direction 4 . Here, the sample tube racks 15 are moved first to a weighing device 8, where they are subjected to weight measurement, and then these sample tube racks 15 are placed in the centrifuge pot 2 7 by means of the handling robot, where they are then centrifuged, and then by the downstream discharge unit 5 in the discharge direction 6 are in turn removed from the centrifuge 1 for analysis.

In addition, a feed buffer can be provided in the feed unit 3 and a discharge buffer can be provided in the discharge unit 5 in order to enable the centrifuge to be fed continuously, and a discharge buffer can be provided in the discharge unit 5 in order to be able to feed the downstream analysis device continuously.

The entire centrifuge 1 , and in particular the handling robot 7 , is controlled by the controller 14 .

In FIG. 6, an embodiment of the handling robot 7 according to the invention in a perspective view is shown. Here, a sample tube rack 15 loaded with numerous sample tubes which contain liquids to be centrifuged is being introduced into a rack holder 30 according to the invention.

The handling robot 7 now basically consists of a pair of grippers 9 arranged parallel to and at a distance from one another, which can be moved three-dimensionally in the three axes by means of at least one stepping motor (not shown) with spindle and brake, with a vertical guide 11 in the Z direction, a horizontal guide 12 in the X direction and a horizontal guide 13 in the Y direction are provided.

All movements can take place simultaneously, with the movement in the horizontal X and Y directions can also be coupled and the gripper for example, just a horizontal rotation by means of another Stepper motor with spindle and brake performs.

The gripper can thus move a gripped sample tube rack 15 to certain spatial points within certain basic values and thus - controlled by the controller 14 - insert the sample tube rack 15 into the rack holder 30 in the centrifuge hanger 23 , which centrifuge hanger 23 over the arms 22 are attached to the pivot point 20 of the swing-bucket rotor, which is shown in more detail in FIGS. 4 and 5.

The motor 10 for the gripper 9 is designed as an electric motor and is located directly above the pair of grippers 9 in order to keep the drive paths as short as possible and to keep the number of deflections as low as possible and thus to optimize the effectiveness and the response behavior of the gripper 9 . Instead of the motor 10 , the gripper 9 can also be moved via a pneumatic control, which is less susceptible to faults.

It is preferred here if the motor 10 itself is only moved in the vertical direction with the vertical guide 11 , but is not moved with the horizontal movement via the horizontal guide 12 , 13 of the gripper 9 in order to keep the moving masses as low as possible.

The same applies to the dosing reservoir 17 , from which the liquid to be dosed is brought in directions 34 via connecting lines 19 and a pump 18 into / out of the fluid reservoir 32 of the rack holder 30 .

The dosing reservoir 17 , the pump 18 and the motor 10 for the gripper are therefore preferably moved only in the vertical direction, but not when the gripper is moved horizontally.

It can also be seen between the two gripper tongs 9 that a weighing device 16 is attached there, so that gripping and moving the sample tube racks 15 and a simultaneous weight determination is possible, as a result of which the loading time of the centrifuge is considerably reduced.

Fig. 6 thus into the slot 31 shows the loading of a test tube racks 15 of the Rackhalters 30, which slide-in compartment 31 is located between the two Fluidumreservoirs 32nd Simultaneous with the introduction of the sample tube racks 15, the weight of this sample tube racks 15 and determines accordingly introduced from the metering reservoir 17 liquid into the Fluidumreservoirs 32 or sucked over the scale device sixteenth

In Figs. 4 and 5, a centrifuge buckets 23, there is shown, in which the rack holder 30 and then placed the sample tube racks 15 °.

The rack holders 30 are thus introduced into the receiving compartment 24 of the centrifuge hanger 23 , which receiving compartment 24 consists of a front boundary 25 and a rear boundary 26 , as well as lateral tongues 27 and a bottom 28 . On the side in the tongues 27 introduced grooves the centrifuge buckets 23 is now connected to the arms 22 of the swing-, the pin 21 now engage the grooves of the lateral tongues 27th In this case, two arms 22 are provided for a centrifuge hanger 23 , these two arms 22 then being connected to the swing-out rotor at the pivot point 20 .

During centrifugation itself, the centrifuge hanger 23 together with the rack holder 30 therein and the sample tube racks 15 are then turned outwards in accordance with the centrifugal forces in the axis of rotation 29 such that the liquid in the sample tubes can be separated.

In Figs. 1 to 3 of the rack holder according to the invention is now 30 in a front view (Fig. 1) shown in cross section in a plan view (Fig. 2) and in a side view in section (Fig. 3).

Starting from a bottom 40 of the rack holder according to the invention is now 30 arranged in mirror symmetry to the longitudinal axis 37, being respectively provided to said longitudinal axis 37 depending on a Fluidumreservoir 32 left and right, which are in turn each mounted approximately mirror-symmetrically to the transverse axis 38 and extending along the vertical axis 39 of the rack holder 30 extend from the floor 40 upwards.

The connection between these two fluid reservoirs 32 is brought about by the connecting channel 33 , which is also located on the bottom 40 and which was introduced from the outside by means of a transverse bore introduced approximately parallel to the transverse axis 38 , so that after its introduction a sealing plug 36 extends from this bore Leakage reasons must be applied.

The connection between the connecting channel 33 and the fluid reservoirs 32 is then achieved via additional through bores 35 which run approximately parallel to the vertical axis 39 . These through holes 35 are then located between the connecting channel 33 and the boundary wall of the respective fluid reservoir 32 located in the vicinity of the base 40 .

The liquid itself can now be introduced into the fluid reservoirs 32 in the feed direction 34 and can also be sucked off in this discharge direction 34 .

In Figs. 1 to 3 can also be seen that the connecting channel 33 extends only parallel to the transverse axis 38, but not so that the insertion compartment 31 on the bottom 40 of the Rackhalters 30 into two unequal parts divided on this symmetrical transverse axis 38 is, since the connecting channel 33 protrudes a bit in the direction of the vertical axis 39 from the floor 40 . Thus, the panel insert are inserted into the two parts 15 so long sample tube racks 15, as well as shorter test tube racks and encounter there the end face of the connecting channel 33 at.

Also it can be provided that this rib is taken of the connecting channel 33 for securing the position of the sample tube racks 15, so that therefore this rib of the connecting channel 33 in a corresponding recess at the bottom of the sample tube racks 15 engages and thus slipping this sample tube -Racks 15 from the slot 31 is no longer possible.

Overall, the loading and unloading device according to the invention for a centrifuge and the rack holder 30 according to the invention with fluid reservoir 32 and the associated methods for loading and unloading such a centrifuge enable a simpler and faster, automated loading and at the same time the acquisition and Operating costs for this reduced. Replacement weights and / or empty inserts with a predetermined weight can be omitted according to the invention.

Drawing legend

1

centrifuge

2

Centrifuge bowl

3rd

Feed unit

4

Feed direction

5

Discharge unit

6

Discharge direction

7

Handling robots

8th

Weighing device from

1

9

Gripper

10th

engine

11

Vertical guidance

12th

Horizontal guidance x

13

Horizontal guidance y

14

control

15

Sample tube rack

16

Weighing device from

7

17th

Dosing reservoir

18th

pump

19th

connection

20th

Swing-bucket rotor pivot

21

Cones

22

poor

23

Centrifuge hangers

24th

Storage compartment for rack holders

25th

front limit

26

rear limit

27

tongue

28

Bottom of

23

29

Axis of rotation

30th

Rack holder

31

Slot

32

Fluid reservoir

33

Connection channel for fluid

34

Feed and discharge direction for fluid

35

Through hole

36

Sealing plug

37

Longitudinal axis

38

Transverse axis

39

Vertical axis

40

Bottom of

30th

Claims (15)

1. Device for loading at least one centrifuge ( 1 ) with a swing-out rotor, which on its rotationally symmetrical arms ( 22 ) has a plurality of centrifuge hangers ( 23 ) with at least one receiving compartment ( 24 ), in which receiving compartment ( 24 ) at least one sample tube that can be equipped with several sample tubes -Rack ( 15 ) can be accommodated, at least one weighing device ( 8 , 16 ) being available for determining the weight, and a handling robot ( 7 ) is available for handling the sample tube rack ( 15 ), which robot can be moved at least in two axes Has gripper ( 9 ), characterized in that a rack holder ( 30 ) can be attached to the receiving compartment ( 24 ) of the centrifuge suspension ( 23 ), which rack holder ( 30 ) has at least one fluid reservoir ( 32 ) in which a fluid for balancing the centrifuge ( 1 ), so that the total weight of the sample tube rack ( 15 ) with the sample tube, the rack - Holder ( 30 ) and the fluid within the fluid reservoir ( 32 ) of the rack holder ( 30 ) of different samples for loading the centrifuge ( 1 ) is essentially constant. 2. Device for loading at least one centrifuge ( 1 ) with a swing-out rotor according to claim 1, characterized in that the rack holder ( 30 ) is introduced into the receiving compartment ( 24 ) of the centrifuge suspension ( 23 ) and the sample tube rack ( 15 ) in an insertion compartment ( 31 ) of the rack holder ( 30 ) can be inserted. 3. Device for loading at least one centrifuge ( 1 ) with a swing-out rotor according to one of claims 1 or 2, characterized in that the handling of the rack holder ( 30 ) also by the handling robot ( 7 ) for the sample tube rack ( 15 ) is accomplished. 4. Device for loading at least one centrifuge ( 1 ) with swing-out rotor according to one of claims 1 to 3, characterized in that the rack holder ( 30 ) has a plurality of fluid reservoirs ( 32 ) and these via connections ( 35 , 36 ) to be communicated vessels are interconnected. 5. A device for loading at least one centrifuge ( 1 ) with a swing-out rotor according to claim 4, characterized in that the fluid reservoirs ( 32 ) are arranged approximately mirror-symmetrically to the longitudinal axis ( 37 ) of the rack holder ( 30 ). 6. Device for loading at least one centrifuge ( 1 ) with a swing-out rotor according to one of claims 4 or 5, characterized in that the fluid reservoirs ( 32 ) are arranged approximately mirror-symmetrically to the transverse axis ( 38 ) of the rack holder ( 30 ). 7. Device for loading at least one centrifuge ( 1 ) with swing-out rotor according to one of claims 4 to 6, characterized in that the fluid reservoirs ( 32 ) are arranged approximately mirror-symmetrically to the vertical axis ( 39 ) of the rack holder ( 30 ). 8. Device for loading at least one centrifuge ( 1 ) with a swing-out rotor according to one of claims 4 to 7, characterized in that the connections ( 35 , 36 ) in the form of through bores ( 35 ) and connecting channels ( 36 ) in the bottom of the rack holder ( 30 ) are provided. 9. Device for loading at least one centrifuge ( 1 ) with a swing-out rotor according to one of claims 1 to 8, characterized in that the weighing device ( 8 ) and / or a dosing reservoir for the rack holder ( 30 ) the handling robot ( 7 ) is connected upstream. 10. Device for loading at least one centrifuge ( 1 ) with swing-out rotor according to one of claims 1 to 9, characterized in that the weighing device ( 16 ) and / or the dosing reservoir ( 17 ) is integrated in the handling robot ( 7 ). 11. Device for loading at least one centrifuge ( 1 ) with a swing-out rotor according to claim 10, characterized in that the weighing device ( 16 ) and / or the dosing reservoir ( 17 ) on and / or between the pair of tongs of the gripper ( 9 ) of the handling Robot ( 7 ) is located and / or within at least one of the tongs of the gripper ( 9 ) of the handling robot ( 7 ). 12. A method for loading and unloading a centrifuge with a loading and unloading device according to one of the device claims 1-11, characterized in that the following steps are carried out:

• a) introducing sample tube racks ( 15 ) at least partially equipped with sample tubes via the feed unit ( 3 ) into the centrifuge ( 1 );
• b) gripping the sample tube racks ( 15 ) by means of the handling robot ( 7 );
• c) determining the weight of the sample tube racks ( 15 ) by means of the weighing device ( 16 ) of the handling robot ( 7 );
• d) feeding the determined amount of fluid into the dosing reservoir ( 17 ) of the handling robot ( 7 ) or feeding fluid into the dosing reservoir ( 17 ) of the handling robot ( 7 ) until it contains at least the determined amount of fluid;
• e) inserting the sample tube racks ( 15 ) into the rack holders ( 30 ) in the centrifuge suspension ( 23 );
• f) Feeding the determined amount of fluid from the dosing reservoir ( 17 ) of the handling robot ( 7 ) into the fluid reservoirs ( 32 ) of the rack holder ( 30 ) to the total weight of the sample tube rack ( 15 ) with sample tube, the rack - To keep the holder ( 30 ) and the fluid within the fluid reservoir ( 32 ) of the rack holder ( 30 ) substantially constant;
• g) centrifugation;
• h) suction of the fluid by means of the handling robot ( 7 ) from the fluid reservoirs ( 32 ) of the rack holder ( 30 );
• i) unloading the sample tube racks ( 15 ) from the centrifuge suspension ( 23 ) by means of the handling robot ( 7 );
• j) Removing the sample tube racks ( 15 ) via the discharge unit ( 5 ) from the centrifuge ( 1 ).

13. A method for loading and unloading a centrifuge with a loading and unloading device according to one of the device claims 1-11, characterized in that the following steps are carried out:

• a) introducing sample tube racks ( 15 ) at least partially equipped with sample tubes via the feed unit ( 3 ) into the centrifuge ( 1 );
• b) determining the weight of the sample tube racks ( 15 ) by means of the separate weighing device ( 8 );
• c) gripping the sample tube racks ( 15 ) by means of the handling robot ( 7 );
• d) feeding the determined amount of fluid into the dosing reservoir ( 17 ) of the handling robot ( 7 ) or feeding fluid into the dosing reservoir ( 17 ) of the handling robot ( 7 ) until it contains at least the determined amount of fluid;
• e) inserting the sample tube racks ( 15 ) into the rack holders ( 30 ) in the centrifuge suspension ( 23 );
• f) Feeding the determined amount of fluid from the dosing reservoir ( 17 ) of the handling robot ( 7 ) into the fluid reservoirs ( 32 ) of the rack holder ( 30 ) to the total weight of the sample tube rack ( 15 ) with sample tube, the rack - To keep the holder ( 30 ) and the fluid within the fluid reservoir ( 32 ) of the rack holder ( 30 ) substantially constant;
• g) centrifugation;
• h) suction of the fluid by means of the handling robot ( 7 ) from the fluid reservoirs ( 32 ) of the rack holder ( 30 );
• i) unloading the sample tube racks ( 15 ) from the centrifuge suspension ( 23 ) by means of the handling robot ( 7 );
• j) Removing the sample tube racks ( 15 ) via the discharge unit ( 5 ) from the centrifuge ( 1 ).

14. A method for loading and unloading a centrifuge according to one of claims 12 or 13, characterized in that method step d) is replaced by:

• a) supplying fluid into the dosing reservoir of the handling robot until it contains at least the determined amount of fluid or until this method step d) is completely omitted, with a large dosing reservoir ( 17 ).

15. A method for loading and unloading a centrifuge according to one of claims 12 to 14, characterized in that process step h) is omitted.