EP3311925B1 - Centrifuge bucket and centrifuge - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

(Laboratory) centrifuges are used, for example, in biotechnology, the pharmaceutical industry, medical technology and environmental analysis. By means of a centrifuge is carried out a centrifugation of a product, in particular a sample container with a sample or substance arranged therein, or a plurality of such products. As a result of the centrifugation, accelerations acting on the product are to be generated so that a substance mixture formed by the sample or the substance is decomposed into components of different density. Depending on the chemical and / or physical properties of the substance mixture, a targeted control of the pressure and / or temperature conditions can additionally take place during the centrifugation. To mention just a few examples, the use of a centrifuge in connection with a polymerase chain reaction (PCR), a determination of hematocrit, cytological examinations or the centrifuging of microtitres, blood bags, petroleum vessels or blood vessels u. Ä.

The invention relates to a centrifuge cup for a centrifuge. Furthermore, the invention relates to a centrifuge equipped with such a centrifuge cup. In the following, the invention will be explained with reference to a centrifuge cup for a centrifuge with a so-called swing-bucket rotor, without any limitation of the invention to this particular type of centrifuge cup or centrifuge.

Centrifuge cups serve to receive sample containers, such as sample cups or sample tubes, which in some cases can be inserted into the centrifuge cup via separate receiving inserts and held therein during centrifugation. The centrifuge cups usually have recordings on opposite sides, which form part-cylindrical bearing surfaces in the upper half plane of the receptacles and are open at the bottom. A centrifuge cup with sample containers disposed therein may be placed in a rotor the centrifuge are used. Here, the sample container is connected to the rotor in that coaxial and facing each other, spaced from each other cylindrical bearing journal of the rotor from below into the opening of the receptacles of the centrifuge cup and come to rest on the bearing surfaces of the recordings. The bearing surfaces of the receptacles specify a bearing axis which corresponds to the central axis of the part cylinder in the case of a partially cylindrical design of the bearing surfaces. The longitudinal axes of the bearing pin of the rotor and the bearing axes of the receptacles are oriented approximately in the circumferential direction to a rotational axis of the rotor. While without rotation of the rotor, the centrifuge cups depend on the gravity of the same downwards, the centrifuge cups are pivoted upon rotation of the rotor about the bearing axis relative to the rotor to the outside.

The centrifuge cups and their receptacles are exposed to high mechanical stresses during operation. On the one hand, the rotors are rotated at high speeds in order to provide large accelerations (in particular accelerations of at least 5,000 × g, at least 10,000 × g or at least 20,000 × g) for the centrifugation of the samples. For this purpose, for example, a drive of the rotor at a speed of at least 4,000 U / min, at least 5,000 U / min, at least 10,000 U / min, at least 15,000 U / min or even at least 20,000 U / min done. The large accelerations produce considerable centripetal or centrifugal forces on the recordings. Since the centrifuge cups are accelerated and decelerated during centrifugation, dynamic loading of the images also takes place. The centrifuge cups and their receptacles should have the highest possible service life, in particular with cycle numbers of possibly more than 50,000 cycles, more than 100,000 cycles or even more than 200,000 cycles. Furthermore, for economical operation of the centrifuge and a possibility of simultaneous centrifugation of a larger number of sample containers, it may be desired to increase the number of sample containers placed in the centrifuge cup and / or to increase the volume of the centrifuge cup, thus including the mass of the centrifuge cup the sample container becomes larger and the forces acting on the receptacles during operation of the centrifuge become correspondingly greater. Finally, a high level of safety is required for a design of the centrifuge cups and receptacles, as mechanical failure of a receptacle when operating at the above high speeds may result in significant damage to the centrifuge and centrifuge environment.

During operation of the centrifuge cups, as a result of the stresses described above, cracks in the area of the receptacles of the centrifuge cups, which require replacement of the centrifuge cup, occur again and again.

STATE OF THE ART

DE 35 39 916 C1 suggests influencing the stress conditions and avoiding stress peaks in the region of the receptacle to form the bottom of the receptacle in a curved manner, wherein a groove arranged in the comb region of the receptacle opens into the curved region of the bottom of the receptacle. Furthermore, it is proposed that the comb portion of the receptacle is formed inclined to the lateral surface of the bearing pin of the rotor, whereby at the beginning of the centrifugation of the comb portion of the receptacle rests only in the region of the outer edge on the bearing pin, while with increasing speed and the elastic deformation of the comb area due to the centripetal force increases the contact area between the comb portion of the receptacle and the journal.

DE 39 03 236 C1 Proposes to increase the wall thickness of the centrifuge cup in the area of the receptacle in order to increase the service life of the centrifuge cup.

US 6,712,750 B2 proposes to extend the maintenance intervals of the centrifuge cup conical end portions of the journals.

According to JP 06-2 85 390 A has the wall of a base of the centrifuge cup in the receiving area a bore whose diameter is greater than the diameter of the journal. In this bore, a receiving insert is used, which is supported with a radial collar axially on the wall of the centrifuge cup and has a bore into which the journal is accurately inserted. Here, the wall thickness of the receiving insert is greater than the wall thickness of the main body of the centrifuge cup.

Also the centrifuge cup according to DE 10 2009 015 111 A1 has a base body which has a bore in the region of the receptacles whose diameter is greater than the diameter of the bearing journals. In these holes, a receiving insert is used, which is to serve as a link between the bearing pin and the main body of the centrifuge cup. The receiving insert may be made of a material with higher strength than the strength of the Be prepared material of the body, whereby the formation of cracks in the contact area between the bearing pin and the centrifuge cup, here the recording inserts to be avoided. By a flat introduction of forces from the receiving inserts in the body, the stress on the body should be reduced. With releasable connection between the receiving insert and the base of the centrifuge cup, a replacement of the receiving insert can be carried out even with a wear or failure of the receiving insert. While aluminum, an aluminum alloy, plastic, a lightweight construction material, a composite material or a carbon fiber material is proposed as the material for the main body of the centrifuge cup, the receiving insert should be made of titanium, a titanium alloy, ceramic, steel or a hard metal.

Further prior art is out US 4,147,294 A known.

The publication DE 10 2011 100 209 A1 discloses a centrifuge cup in which the mechanical strength of the centrifuge cup is ensured by the design of the wall thickness of a base of the centrifuge cup and suitable reinforcements and ribs. For an embodiment of the centrifuge cup, a retaining clip in the form of an inverted W is formed on the upper edge of the base body by connecting the side legs of the W to the base body. The middle limbs of the W form a nose, which serve the pivotable mounting of a handle. On the one hand the handling of the centrifuge cup is possible on the handle. On the other hand, the handle ensures in a closed position a pressing of a lid to the main body of the centrifuge cup.

Further prior art is from the documents JP 2005 152819 A and EP 0 025 945 B1 known.

OBJECT OF THE INVENTION

The invention has for its object to propose an alternative embodiment for a centrifuge cup, which is particularly improved in terms of mechanical strength, durability and / or susceptibility to failure due to cracking. Furthermore, the invention has for its object to propose an alternative embodiment of a centrifuge.

SOLUTION

The object of the invention is achieved with the features of the independent claims. Further preferred embodiments according to the invention can be found in the dependent claims.

DESCRIPTION OF THE INVENTION

According to the invention, the centrifuge cup has a base body (one or more parts) which has a recess in the region of the receptacles for the bearing journal. In this case, the recess may pass through a wall of the main body or may not be continuous, so that the recess has a bottom. The recess serves (directly or indirectly) to prevent cracking or delay of crack propagation in the body due to centripetal force acting on the centrifuge cup by centrifugation.

The centrifuge cup according to the invention has a receptacle. The receptacle has a bearing surface for a bearing journal of the centrifuge. The bearing surface defines a bearing axis about which is pivotable during centrifugation of the centrifuge cups relative to the rotor.

The centrifuge cups known from the prior art follow the prejudice of those skilled in the art that in their constructive design as far as possible any formation of cracks is to be avoided. For this reason, as explained above, thickening of the wall thickness, special designs of the bearing journal and the use of recording inserts use.

While according to the document DE 10 2009 015 111 A1 the bearing surface of a receiving insert, that is separately formed from the main body of the centrifuge cup, according to the invention, the bearing surface of the main body itself is formed. Thus, for a possible approach according to the invention, under certain circumstances, it is deliberately accepted that in some cases cracking occurs in the area of the bearing surface formed by the main body due to a lack of a receiving insert with a higher strength. Yet can be ensured according to the invention in a surprising manner, a high reliability and fatigue strength of the centrifuge cup: According to the invention, the bearing surface (viewed in the radial direction with respect to the bearing axis) between the bearing axis and the recess. Thus, the recess, as viewed from the bearing axis, "displaced into the interior" of the body or the recess is spaced from the bearing surface.

Surprisingly, it has been found that even for such a configuration of crack propagation of a crack forming in the region of the bearing surface, it can be stopped in good time by preventing the propagation of the crack beyond the recess through the recess. In the direction of the stress of the centrifuge cup and / or in the direction of the expected propagation of the crack during centrifugation as a result of the centripetal force, the centrifuge cup has, in particular, two material regions of the main body which are separated from one another via the recess. If a crack occurs in the region of the bearing surface, it can progress in the first material region up to the recess. The crack propagation into the second material region is then prevented by the recess, so that despite the possibly existing crack of the centrifuge cup (at least temporarily) can continue to be used.

• Die Ausbildung der Lagerfläche durch einen hochfesten Aufnahmeeinsatz gemäß DE 10 2009 015 111 A1 hat zur Folge, dass die Lagerfläche ebenfalls von einem hochfesten Material ausgebildet ist. Eine etwaige Formabweichung der Mantelfläche des Lagerzapfens von der Lagerfläche des Aufnahmeeinsatzes kann nicht oder nur in reduziertem Ausmaß durch eine elastische oder plastische Verformung der Lagerfläche ausgeglichen werden. Dies führt zu Spannungsspitzen im Bereich der Mantelfläche des Lagerzapfens, welche einen erhöhten Verschleiß des Lagerzapfens zur Folge haben können. Im Rahmen der Erfindung ist durchaus möglich, dass die Lagerfläche von einem Grundkörper mit einer verringerten Festigkeit ausgebildet wird, so dass auch elastische oder plastische Verformungen der Lagerfläche möglich sind.
• Auch für eine schwingungstechnische Auslegung infolge der hochdynamischen Prozesse bei dem Betrieb einer Zentrifuge ist unter Umständen die Verwendung eines nicht hochfesten Materials im Bereich der Lagerfläche wünschenswert.
• Infolge der hohen Drehzahlen des Rotors mit dem daran gehaltenen Zentrifugenbecher und sich daraus ergebenden hohen Zentripetalkräften ist eine exakte Vorgabe der Lagerachsen erforderlich. Bei der Verwendung eines Aufnahmeeinsatzes gemäß DE 10 2009 015 111 A1 summieren sich Fertigungstoleranzen einerseits des Grundkörpers und hier der Aufnahme für den Aufnahmeeinsatz und andererseits des Aufnahmeeinsatzes und der von diesem ausgebildeten Lagerfläche auf, wobei zusätzlich noch etwaige Montageungenauigkeiten bei der Montage des Aufnahmeeinsatzes in den Grundkörper zu berücksichtigen sind. Dies erfordert eine hohe Montage- und Fertigungsgenauigkeit. Hingegen bildet erfindungsgemäß der Grundkörper des Zentrifugenbechers unmittelbar die Lagerfläche aus, womit durch die hinreichend exakte Fertigung des Grundkörpers ohne zusätzliche Beachtung von Toleranzen eines etwaigen Aufnahmeeinsatzes und ohne erhöhte Anforderungen an eine Montagegenauigkeit der Ort und die Ausrichtung der Lagerachse exakt vorgegeben werden kann.

In the following, some possible advantages and possibly used technical functions of the embodiment according to the invention are mentioned, without a limitation of the invention to embodiments with these advantages or functions:

• The formation of the bearing surface by a high-strength receiving insert according to DE 10 2009 015 111 A1 As a result, the bearing surface is also formed by a high-strength material. Any deviation in shape of the lateral surface of the journal from the bearing surface of the receiving insert can not be compensated or only to a reduced extent by an elastic or plastic deformation of the bearing surface. This leads to voltage peaks in the region of the lateral surface of the bearing journal, which can result in increased wear of the journal. In the context of the invention is quite possible that the bearing surface is formed by a body with a reduced strength, so that elastic or plastic deformation of the bearing surface are possible.
• Even for a vibrational design due to the highly dynamic processes in the operation of a centrifuge, the use of a non-high-strength material in the area of the bearing surface is desirable under certain circumstances.
• Due to the high rotational speeds of the rotor with the centrifuge cup held thereon and resulting high centripetal forces an exact specification of the bearing axes is required. When using a pick-up insert according to DE 10 2009 015 111 A1 Manufacturing tolerances on the one hand of the body and here the recording for the receiving insert and on the other hand of the receiving insert and formed by this bearing surface add up, with any additional assembly inaccuracies in the assembly of the receiving insert are to be considered in the body in addition. This requires a high assembly and manufacturing accuracy. By contrast, according to the invention, the base body of the centrifuge cup directly forms the bearing surface, which can be specified exactly by the sufficiently accurate production of the body without additional attention to tolerances of any recording insert and without increased demands on a mounting accuracy of the location and orientation of the bearing axis.

The invention includes embodiments in which the recess is completely filled by the insert, as well as embodiments in which the recess is filled only in a portion of the insert, while in at least one other portion of the recess remains a space.

The experiments on which the invention is based have shown that crack propagation can already be stopped solely by the provision of the recess in a location or in a region which is arranged in the direction of a possible crack propagation or in the direction of the stress due to the centripetal force.

• die Ausbildung eines Risses in dem ersten Materialbereich,
• die Übertragung des Risses von den ersten Materialbereich zu dem Einsatz,
• den Fortschritt des Risses durch den Einsatz und
• die Übertragung des Risses von dem Einsatz zu dem zweiten Materialbereich,

womit die Wahrscheinlichkeit eines Risses in den zweiten Materialbereich drastisch reduziert ist. Dieser Effekt kann bereits genutzt werden, wenn über den Einsatz dasselbe Material genutzt wird wie für den Grundkörper des Zentrifugenbechers. Vorzugsweise findet allerdings für den Einsatz ein Material Einsatz, dessen Festigkeit oder Widerstand gegen eine Rissbildung größer ist als die Festigkeit oder der Widerstand gegen eine Rissbildung des Materials des Grundkörpers. Beispielsweise kann der Einsatz aus Titan, einer Titanlegierung, Keramik, Stahl oder einem Hartmetall hergestellt sein.For an alternative of the invention, however, an insert is inserted into the recess. When a crack in the first material region of the base body reaches the recess between the bearing surface and the recess, crack propagation requires the creation of a corresponding crack in the insert. However, this does not affect the contact surface of the insert with the base body, the same stresses and any voltage peaks as in the bearing surface of the body due to the contact with the bearing pin. Rather distribute it Depending on the design of the contact surface between the main body and the insert, the stresses, whereby the risk of the formation of a crack in the insert is prevented or at least reduced. Even if it comes in the use of the formation of a crack, this crack would also be transferred from the use of a second material region of the base body, which is arranged on the side facing away from the bearing axis of the recess, but where the above applies accordingly and in view of the large-area contact area between the insert and the second material region of the main body, stress peaks which can initiate a crack in the second material region are avoided. Finally, the formation of a crack in the second material region requires

• the formation of a crack in the first material area,
• the transfer of the crack from the first material area to the insert,
• the progress of the crack through the use and
• the transfer of the crack from the insert to the second material region,

whereby the probability of a crack in the second material area is drastically reduced. This effect can already be used if the same material is used over the insert as for the main body of the centrifuge cup. Preferably, however, a material is used for the use whose strength or resistance to cracking is greater than the strength or resistance to cracking of the material of the body. For example, the insert can be made of titanium, a titanium alloy, ceramic, steel or a hard metal.

For another alternative of the invention, a plurality of recesses are arranged in the region of a receptacle. These are arranged at different distances from the bearing axis and with partial overlaps in the circumferential direction. As a result of the partial overlaps, the likelihood of crack propagation between adjacent recesses is reduced since the partial overlaps "block" a crack propagation in the radial direction and thus crack propagation beyond the recesses and inserts requires a crack advance in the body deflected circumferentially about the bearing axis.

It is possible within the scope of the invention that a recess (and any insert arranged therein) is arranged on the centrifuge cup only in the region of a receptacle.

Preferably, however, a recess and a possible insert are each in the area of both receptacles. For a particular proposal of the invention, a plurality of recesses (and possibly inserts therein) are present in the region of at least one receptacle, wherein it is also possible that in some recesses inserts are present, while this is not the case in other recesses.

For the connection between an insert and a recess, there are many possibilities within the scope of the invention. To mention only a few of these, holding the insert in an associated recess of the base body of the centrifuge cup by a material or adhesive connection (in particular gluing, welding, soldering), a press fit, a screw and / or a locking pin can be done.

A shape of the insert and the associated recess (in particular with respect to the longitudinal axis, the depth, the inner surface with respect to the bearing axis and / or the outer surface with respect to the bearing axis) may be arbitrary within the scope of the invention. In this case, the shaping can take into account the stresses which form during operation and / or further space requirements of the centrifuge cup. Preferably, the recess (and thus also any insert inserted therein) has a curved longitudinal axis.

In this case, the curvature can be formed with any desired constant curvature or changing curvature, it being also possible that an alternating curvature with at least one inflection point is present.

For a preferred embodiment of the invention, the curvature is formed concentrically to the bearing axis. In this way, it can be utilized that the first material region of the main body between the recess with the insert and the bearing surface over the partial circumferential region of the recess with the insert has approximately the same extent in the direction of view radially to the bearing axis, which can be advantageous for the stress ratios and avoidance a possible crack formation and / or the space design.

For these or other embodiments of the invention, the invention takes into account the fact that a possible crack u. U. not at a defined location, but can be initiated in a partial peripheral area of the storage area. Furthermore, a crack does not proceed exactly in a predetermined direction, in particular radially to the bearing axis.

On the other hand, the centripetal force in the area of the bearing surface acts in different radial directions depending on the rotational speed of the centrifuge and the resulting pivoting angle of the centrifuge cup about the bearing axis. This fact can be taken into account for a proposal of the invention in that the recess (and any insert disposed therein) extends / extend over a partial circumferential area of the bearing axis in the base body.

For a particular proposal of the invention, the recess and any insert disposed therein are / are formed hollow cylinder segment-shaped, wherein preferably the center of the hollow cylinder segment lies on the bearing axis. Thus, the insert in a direction radially to the bearing axis has a constant extent over the circumference.

In a further embodiment of the invention it is proposed that the recess passes through the wall formed by the main body. The depth of the insert corresponds to the wall thickness of the wall in the boundary or surrounding area of the recess, so that the insert can be flush with the wall of the base body.

In the event that a plurality of recesses and inserts are arranged in the region of a receptacle, these can be arranged for a proposal of the invention with different distances from the bearing axis and with partial overlaps in the circumferential direction. As a result of the partial overlaps, the likelihood of crack propagation between adjacent recesses and inserts is reduced since the partial overlaps will "block" crack propagation in the radial direction and thus crack propagation beyond the recesses and inserts will necessitate a crack propagation in the body circumferentially deflected about the bearing axis.

For a dimensioning of the first material region of the base body, which is arranged between the recess and the bearing surface, there are many possibilities. Investigations have shown that, for a possible embodiment, the first material region between the recess and the bearing surface forms a transition region whose extent is at least 3 mm radially to the bearing axis. The second material region, which is arranged on the side facing away from the bearing axis of the recess, may have a smaller, a corresponding or a greater extent radially to the bearing axis.

Advantageous developments of the invention will become apparent from the claims, the description and the drawings. The advantages of features and of combinations of several features mentioned in the description are merely exemplary and can take effect alternatively or cumulatively, without the advantages having to be achieved by embodiments according to the invention. Without thereby altering the subject matter of the appended claims, as regards the disclosure of the original application documents and the patent, further features can be found in the drawings, in particular the illustrated geometries and the relative dimensions of several components and their relative arrangement and operative connection. The combination of features of different embodiments of the invention or of features of different claims is also possible deviating from the chosen relationships of the claims and is hereby stimulated. This also applies to those features which are shown in separate drawings or are mentioned in their description. These features can also be combined with features of different claims. Likewise, in the claims listed features for further embodiments of the invention can be omitted.

The features mentioned in the patent claims and the description are to be understood in terms of their number that exactly this number or a greater number than the said number is present, without requiring an explicit use of the adverb "at least". If, for example, a recess or an insert is mentioned, it should be understood that exactly one recess or insert, two recesses or inserts or more recesses or inserts are present. These features may be supplemented by other features or be the only characteristics that make up the product in question.

The reference numerals contained in the claims do not limit the scope of the objects protected by the claims. They are for the sole purpose of making the claims easier to understand.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1

zeigt einen Zentrifugenbecher in räumlicher Ansicht schräg von oben.

Fig. 2

zeigt einen Zentrifugenbecher gemäß dem Stand der Technik mit einem durchgehenden Riss bei Blickrichtung in Richtung der Lagerachse.

Fig. 3

zeigt einen Zentrifugenbecher mit einem durch eine Ausnehmung (ggf. mit einem darin angeordneten Einsatz) blockierten Riss bei Blickrichtung in Richtung der Lagerachse.

Fig. 4 und 5

zeigen weitere Zentrifugenbecher bei Blickrichtung in Richtung der Lagerachse.

In the following the invention will be further explained and described with reference to preferred embodiments shown in the figures.

Fig. 1

shows a centrifuge cup in a spatial view obliquely from above.

Fig. 2

shows a centrifuge cup according to the prior art with a continuous crack when looking in the direction of the bearing axis.

Fig. 3

shows a centrifuge cup with a through a recess (possibly with an insert disposed therein) blocked crack when looking in the direction of the bearing axis.

4 and 5

show more centrifuge cups when looking in the direction of the bearing axis.

DESCRIPTION OF THE FIGURES

Fig. 1 shows a centrifuge cup 1. A one-piece base body 2 forms a circumferentially closed lateral wall 3 and a bottom wall 4 from. The lateral wall 3 and the bottom wall 4 define an upwardly open interior space 5, in which (with or without additional receiving insert) sample containers can be used and in which the sample containers are accommodated during the centrifugation. The lateral wall 3 basically has a constant height, although in the area of receptacles 6a, 6b the wall 3 has a greater height, forming retaining areas 8a, 8b. In this way, on the one hand ensures that a bearing axis 9 can be arranged at a sufficient height. On the other hand, the wall 3 in the holding areas 8a, 8b above the receptacles 6a, 6b formed bearing surfaces 10a, 10b still sufficient material to ensure the strength of the centrifuge cup 1 at the centripetal forces acting during centrifugation. It is possible that the lateral wall 3 has a constant wall thickness over the circumference or that the wall thickness of the centrifuge cup 1 in the holding areas 3 is increased. The receptacles 6a, 6b are formed on opposite sides. For the recordings 6a, 6b and the associated components, the same reference numerals are used, the individual recordings and components are then distinguished by a supplementary letter a, b. If a description applies to different components marked with the letters a, b, reference is made in the present description and in the patent claims partly to the assigned reference number without the use of the additional letters a, b.

The design of the receptacles 6a, 6b will be explained with reference to the receptacle 6a, wherein the corresponding applies to the receptacle 6b:
In the lateral wall 3, a recess 11 a is introduced from the outside to form the receptacle 6 a in the direction of the bearing axis 9. The recess 11a is of open-plan design in cross-section, that is to say in a plane vertical to the bearing axis 9, wherein the opening 20a of the recess 11a is oriented downwards. The recess 11a is not in the direction of the bearing axis 9 through the wall 3, so that it has a bottom 12a.

• Im oberen Endbereich oder Kammbereich ist der Querschnitt der Ausnehmung 11a begrenzt durch eine zylindersegmentförmige Lagerfläche 10a, deren Umfangswinkel ca. 120° bis 170°, vorzugsweise 130° bis 150° beträgt.
• An die Lagerfläche 10a schließen sich nach unten öffnende, hier geradlinige Einführflächen 14a, 15a und sich wiederum hieran nach unten anschließende, hier ebenfalls geradlinige Einführflächen 16a, 17a, deren Öffnungswinkel größer ist als der der Einführflächen 14, 15, an.
• Über parallele Begrenzungsflächen 18a, 19a erstreckt sich die Ausnehmung 11a bis zu der unteren Öffnung 20a der Ausnehmung 11a.

The cross section of the open-edged recess 11a is formed with the following subregions:

• In the upper end region or comb region, the cross section of the recess 11a is bounded by a cylinder-segment-shaped bearing surface 10a whose circumferential angle is approximately 120 ° to 170 °, preferably 130 ° to 150 °.
• The bearing surface 10a is followed by downwardly opening, here rectilinear insertion surfaces 14a, 15a and, in turn, downwardly adjoining here likewise rectilinear insertion surfaces 16a, 17a whose opening angle is greater than that of the insertion surfaces 14, 15.
• Via parallel boundary surfaces 18a, 19a, the recess 11a extends to the lower opening 20a of the recess 11a.

Here, the mentioned subregions of the recess 11a are mirror-symmetrical to the vertical axis. The centrifuge cup 1 can be placed with the receptacles 6a, 6b from above on bearing journal of a rotor of the centrifuge facing each other (not shown here). Here, the bearing pins enter through the opening 20a, 20b in the recesses 11a, 11b. With the further movement of the centrifuge cup 1 down a guide or self-centering of the centrifuge cup 1 relative to the two coaxial bearing pin of the rotor through the boundary surfaces 18, 19 and the insertion surfaces 14, 15, 16, 17, until the lateral surface of the bearing pin comes to rest on the bearing surfaces 10a, 10b. Preferably, the diameter of the bearing surfaces 10a, 10b corresponds to the diameter of the lateral surface of the bearing pin, so that there is a large contact surface. In the thus formed Operating state of the centrifuge cup 1 relative to the rotor, the end faces of the bearing journal adjacent (in particular, with a slight play) to the bottoms 12a, 12b of the recesses 11a, 11b are arranged, it being also possible that the centrifuge cup 1 in the region of the bottom 12a, 12b is trapped between the end faces of the bearing pin, whereby the axial position of the centrifuge cup can be specified relative to the rotor 9 in the direction of the bearing axis.

In that regard, the embodiment still corresponds to the embodiment according to the prior art, wherein basically any other known embodiment of a centrifuge cup (with the additional features described below) can be used within the scope of the invention.

Fig. 2 shows a centrifuge cup 1 according to the prior art with a forming in the region of the bearing surface 10 crack 21. A crack 21 forming in the region of the bearing surface 10 as shown by the holding portion 8 radially to the bearing axis 9 advance until it is completely through the Holding portion 8 and extends to the upper end of the side wall 3, which may be at the latest to a failure of the centrifuge cup 1. In this case, the holding region 8 designates the material region which remains in the direction of loading during the centrifugation between the bearing surface 10 and the upper end region of the lateral wall 3 and thus has to absorb the centripetal force.

As in the Fig. 1 and 3 can be seen, according to the invention in the holding area 8 above the bearing surface 10 each have a recess 22 which is bounded by the material of the base body 2. The recess 22 separates in the holding region 8 a first material region 23 and a second material region 24. The first material region 23 is in this case arranged between the bearing surface 10 and the recess 22. The second material region 24 is arranged on the side facing away from the bearing axis 9 of the recess 22 and extends in the radial direction to the bearing axis 9 of the recess 22 to the upper edge of the wall 3. The bearing surface 10 is between the recess 22 and the bearing axis 9 arranged.

The recess 22 extends for the illustrated embodiment over a partial circumference of the bearing axis 9, preferably over the entire upper half-plane. In the recess 22, an insert 25 is inserted, which completely fills the recess 22. The insert 25 and the recess 22 have a curved longitudinal axis 26. An inner surface 27 and an outer surface 28 of the insert 25 (and correspondingly the associated inner surface and outer surface of the recess 22) are curved. Here, the recess 22 has over the longitudinal axis 26 a constant transverse extent and extension in the depth direction. Here, preferably, the recess 22 is formed continuously and without bottom and end faces of the insert 25 are arranged flush with the inner surface and the outer surface of the wall 3 in the holding area 8. For the illustrated embodiment, the recess 22 and the insert 25 on a hollow cylinder segment-like portion 29, which is in Fig. 3 extends at least from a 10:00 o'clock position to a 2:00 o'clock position, as well as rectilinear portions 30, 31 which respectively adjoin the end portions of the hollow cylinder segment-like portion 29. These rectilinear portions 30, 31 are preferably oriented parallel to the insertion surfaces 16, 17. The rectilinear portions 30, 31 preferably terminate in the lower half-plane, ie below the bearing axis 9.

Fig. 3 shows the centrifuge cup 1 with a crack 21, which has been initiated in the region of the bearing surface 10. During operation of the centrifuge with the centrifuge cup 1, the crack 21 has progressed so far that it extends as far as the recess 22 and thus completely through the first material region 23. However, crack propagation is prevented by the recess 22 and the insert 25 arranged therein. While the carrying capacity of the first material region 23 is at least impaired as a result of the crack 21, the transmission of the forces and stresses from the first material region 23 via the recess 22 and the insert 25 to the second material region 24 with a good distribution of the acting forces and stresses, so that the crack can not continue in the second material region 24. Even in the event that no insert 25 is arranged in the recess 22, a crack progress is blocked by the then in particular continuous recess 22.

It is also possible that the insert 25 is inserted with a local game or with a game in at least a portion or a transition fit into the recess 22, wherein any remaining game then under certain circumstances only with the mechanical stress due to centrifugation and / or a resulting elastic or plastic deformation is closed.

Fig. 4 shows a further embodiment of a centrifuge cup 1, wherein in the region of each receptacle 6, two recesses 32, 33 are formed by the base body 2, wherein in this optionally also an associated insert 34, 35 used and can be held therein. Here, the recesses 32, 33 and possibly associated inserts 34, 35 are basically curved according to the embodiment according to Fig. 3 , However, here are the two recesses 32, 33 and associated inserts 34, 35 with different radii concentric, but radially offset from the bearing axis 9. Here, a recess 32 with associated insert 34 extends approximately from a 10:00 o'clock position to a 1:00 o'clock position, while the other recess 33 with associated insert 35 extends from an 11:00 o'clock position extends to a 2:00 o'clock position. Between the two recesses 32, 33 there results a third material region 36, which extends from the 11:00 o'clock position to the 1:00 o'clock position and has a constant extension in the direction radial to the bearing axis 9. If a crack is to propagate from the bearing surface 10 into the second material region 24, this requires that the crack has to propagate through the third material region 36 in the circumferential direction.

Fig. 5 shows a further embodiment of a centrifuge cup 1, wherein in the holding area 8, a plurality of recesses 37A, 37B, ... and possibly associated inserts 38A, 38B, ... are present. Here, the recesses 37 are arranged distributed with associated inserts 38 in the lateral wall 3, that they are offset in the direction of the stress and in the direction of a possible propagation of a crack to each other that a propagation of a crack on the recesses 37 and inserts 38th is only possible via a partial deflection, in particular in the circumferential direction. Preferably, the paths of a crack are thus radially blocked in the region of the recesses 37 to the bearing axis 9 through the recesses 37 and inserts 38. It is possible that such recesses 37 and inserts 38 are distributed over the entire partial circumference of the bearing surface 10. For the in Fig. 5 illustrated embodiment, these recesses 37 and inserts 38 are preferably in the maximum during centrifugation claimed material area of the holding portion 8, which may be here, for example, for a 11:30 clock peripheral area and a 13:30 clock peripheral area of the case.

For all illustrated embodiments ( Fig. 1 . 3 . 4 and 5 ), the implementation of the invention can be carried out with or without the use of inserts in the recesses, wherein an embodiment with only one recess without insert therein is not included in the wording of the claims.

The first material region 23 forms a transfer region 13, in which, under certain circumstances, crack propagation is tolerated and which transfers the acting forces and stresses to the region of the recess or onto the insert.

Preferably, the material of the base body 2 of the centrifuge cup 1 is aluminum, an aluminum alloy, a plastic, optionally with embedded carbon fibers, a lightweight plastic, a composite material or the like. The at least one insert may consist of the same material or a different material. Preferably, the insert is made of titanium, a titanium alloy, ceramic, steel, a hard metal, a plastic or a plastic with embedded carbon fibers, a lightweight construction material, a composite material u. ä.

It is possible that the insert is received with a game, in particular in the range of 1 / 10th mm to 2 / 10th mm in the associated recess, in which case, for example, a fastening, fixing and holding the insert via a pin or a screw is made. It is possible that the connection between the insert and the recess is formed positively or non-positively.

LIST OF REFERENCE NUMBERS

1

centrifuge tube

2

body

3

lateral wall

4

bottom wall

5

inner space

6

admission

8th

holding area

9

bearing axle

10

storage area

11

recess

12

ground

13

Frequency response

14

lead-in

15

lead-in

16

lead-in

17

lead-in

18

boundary surface

19

boundary surface

20

opening

21

Crack

22

recess

23

first material area

24

second material area

25

commitment

26

longitudinal axis

27

palm

28

outer surface

29

hollow cylinder segment-like partial area

30

rectilinear section

31

rectilinear section

32

recess

33

recess

34

commitment

35

commitment

36

third material area

37

recess

38

commitment

Claims (11)

1. Centrifuge bucket (1) with

   a) a base body (2) comprising a recess (22; 32, 33; 37), which serves to directly or indirectly inhibit formation of a tear (21) or to delay a progression of a tear (21) in the base body (2) due to a centripetal force effective onto the centrifuge bucket (1) due to centrifugation, and

   b) an accommodation (6) comprising a bearing surface (10) for a bearing pin of the centrifuge defining a bearing axis (9),

   c) where the bearing surface (10) is formed by the base body (2) and

   d) the bearing surface (10) when viewed in the radial direction with respect to the bearing axis (9) is arranged between the bearing axis (9) and the recess (22; 32, 33; 37),
   characterised in that

   e) an insert (25; 34, 35; 38) is inserted into the recess (22; 32, 33; 37) or recesses (32, 33; 37a, 37b, ...) are arranged with different distances from the bearing axis (9) and partial overlaps in the circumferential direction.
2. Centrifuge bucket (1) according to claim 1, characterised in that multiple recesses (32, 33; 37a, 37b, 37c, ...) and multiple inserts (34, 35; 38a, 38b, 38c, ...) are present.
3. Centrifuge bucket (1) according to claim 1 or 2, characterised in that the or at least one insert (25; 34, 35; 38) is held in the recess (22; 32, 33; 37) of the base body (2) via

   a) a material connection or an adhesive connection,

   b) an interference fit,

   c) a screw and/or

   d) a securing pin.
4. Centrifuge bucket (1) according to one of claims 1 to 3, characterised in that the or at least one insert (25; 34, 35; 38) and/or the recess (22; 32, 33; 37) comprises a curved longitudinal axis (26).
5. Centrifuge bucket (1) according to claim 4, characterised in that the curvature is realized to be concentric to the bearing axis (9).
6. Centrifuge bucket (1) according to one of claims 1 to 5, characterised in that the or at least one insert (25; 34, 35; 38) and at least one recess (22; 32, 33; 37) extend over a part of the circumferential area of the bearing axis (9) in the base body (2).
7. Centrifuge bucket (1) according to one of claims 1 to 6, characterised in that the or at least one insert (25; 34, 35; 38) and at least one recess (22; 32, 33; 37) are realized to be shaped as a segment of a hollow cylinder.
8. Centrifuge bucket (1) according to one of claims 1 to 7, characterised in that

   a) the or a recess (22; 32, 33; 37) extends through a wall (3) formed by the base body (2),

   b) the depth of the or at least one insert (25; 34, 35; 38) corresponds to a wall thickness of the wall (3) in the neighbourhood of the recess (22; 32, 33; 37),

   c) the front face of the insert (25; 34, 35; 38) ends flush with the outer surface of the wall (3) in the neighbourhood of the recess (22; 32, 33; 37) and

   d) the other front face of the insert (25; 34, 35; 38) ends flush with the inner surface of the wall (3) in the neighbourhood of the recess (22; 32, 33; 37).
9. Centrifuge bucket (1) according to one of the preceding claims, characterised in that inserts (34, 35; 38a, 38b, ...) and recesses (32, 33; 37a, 37b, ...) are arranged with

   a) different distances from the bearing axis (9) and

   b) partial overlaps in the circumferential direction.
10. Centrifuge bucket (1) according to one of the preceding claims, characterised in that between the or at least one recess (22; 32, 33; 37) and the bearing surface (10) the base body (2) forms a transfer portion (13), the extension of which radially to the bearing axis (9) is at least 3 mm.
11. Centrifuge with a centrifuge bucket (1) according to one of the preceding claims.

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