Flow-through centrifuge and compensating rotor guide device

Abstract

The present invention relates to a flow-through centrifuge, comprising a rotor with at least one centrifugation chamber, which is rotated about a rotor axis (7) at any rotor speed. The flow-through centrifuge comprises a connecting strand (12) through which connecting lines (16, 17) extend. Through the connecting lines (16, 17), a medium can be supplied to and discharged from the centrifugation chamber during operation of the flow-through centrifuge with the rotor rotating. One end region (18) of the connecting strand (12) is fixed to the housing, while the other end region (19) of the connecting strand (12) rotates together with the rotor. To prevent twisting of the connecting strand 12, the connecting strand 12 is guided in a compensating rotor guide device 20 (particularly a guide pipe 21), which is rotated around the rotor axis 7 at half the rotor speed. According to the invention, the compensating rotor guide device 20 has a guide profile 27, the radius of curvature 32 of which in a first guide profile section 28 is greater than the radius of curvature 33 of which in a second guide profile section 29. This can improve the service life of the connecting strand 12.

Description

[Technical Field]

[0001] The present invention relates to a flow-through centrifuge, in which at least one medium (in particular a fluid, liquid, suspension, etc.) is supplied to and / or discharged from the centrifugation chamber at least temporarily while the centrifugation chamber is rotating. The medium can be arranged in a container in the centrifugation chamber. The at least one medium is in particular the medium to be centrifuged, a purge liquid, a washing or buffer solution, a medium extracted and transformed from the centrifuged medium and / or a sediment in the centrifugation chamber.

[0002] To give just a few non-limiting examples, a flow-through centrifuge may be a blood centrifuge in which the medium to be centrifuged is blood and the extracted and transformed medium or sediment is blood cells or blood particles, or it may be a flow-through centrifuge in which cells, microcarriers or other particles contained in the medium are to be obtained from the medium. It is also possible that the medium to be centrifuged is not a pure liquid, but rather the medium is a solution or suspension containing particles, such as cells, cell debris or cell debris.

[0003] Flow-through centrifuges are used, for example, in biopharmaceutical companies to produce biopharmaceutical products or in bioprocessing applications. They may then be used, for example, for the harvesting and / or clarification of cells or microcarriers, and the cells thus harvested may also be used for cell therapy. A further field of use for flow-through centrifuges is, for example, the production of vaccines.

[0004] The present invention also relates to a compensating rotor guide device. [Background technology]

[0005] The flow-through centrifuges mentioned in the preamble are sold, for example, by the company Sartorius AG (German: Sartorius AG, Otto-Brenner-Strasse 20, 37079 Göttingen, Germany) and associated companies under the trademark "Ksep" (registered trademark). On the Internet page for these flow-through centrifuges (Non-Patent Document 1), the functional principle of a flow-through centrifuge, which may also be used in the present invention, is explained as follows on the basis of the linked video: The rotor of a flow-through centrifuge has any number of centrifugation chambers (e.g., two or four), which may be formed as blood bags held in the rotor body and uniformly distributed around the periphery. The centrifugation chambers are arranged at the same radial distance from the rotation axis of the rotor. A first connecting line opens into the centrifugation chambers radially inward, while a second connecting line opens into the centrifugation chambers radially outward. In a first operating phase, while the centrifugation chambers rotate with the rotor, a first medium, for example, blood, is supplied to the centrifugation chambers via the second connecting line. As a result of centrifugation in the centrifugation chambers, particles contained in the blood (e.g., blood cells) settle outward, while the remaining medium (i.e., the medium supplied radially outward and reduced by the particles displaced radially outward) is discharged radially inward from the centrifugation chambers via the first connecting line. During this first operating phase, the first connecting line is a discharge line, while the second connecting line is a supply line. As this operation continues, the proportion and concentration of particles in the centrifuge chamber increases until the centrifuge chamber is largely, and eventually completely, filled with particles. In a subsequent, optional, second operating phase, washing of the particles in the centrifuge chamber is performed. For this purpose, a washing or buffer solution is introduced into the centrifuge chamber via the second connecting line. The washing or buffer solution purges the centrifuge chamber and is discharged radially inward via the first connecting line. Even during this operating phase, the centrifuge chamber rotates with the rotor, preventing particles from leaving the centrifuge chamber with the washing or buffer solution via the first connecting line as a result of the centrifugal force acting thereon. During the second operating phase, the first connecting line is still used as a discharge line for the washing or buffer solution, while the second connecting line is still used as a supply line for the washing or buffer solution. In the following third operating phase, the rotation of the centrifuge chamber together with the rotor continues.In the third operating phase, the flow direction through the centrifuge chamber is reversed, and particles are removed from the centrifuge chamber via the second connecting line, while a wash solution or buffer solution can be replenished into the centrifuge chamber via the first connecting line. The third operating phase ends when all particles have been removed from the centrifuge chamber. Further cycles having the three described operating phases can then be performed sequentially.

[0006] In EP 0 699 597 B1 it is possible to see the construction of a media network, which is connected to connecting lines and ensures the various operating phases. With regard to this media network, the included pump assemblies, process control units, additional filter assemblies, containers for the different media, and with regard to the process flows, reference is additionally made to EP 0 699 599 B1, EP 0 699 599 B1 and EP 0 699 599 B1.

[0007] Patent Document 3 describes problems that can occur in flow-through centrifuges when using rotary feedthroughs to connect lines that rotate with the rotor. This is because rotary feedthroughs are prone to leaks and entail the risk of undesired contamination of the medium. On the other hand, Patent Documents 4, 5, 6, and 7 describe the use of connecting strands into which connecting lines can be integrated. One end region of the connecting strand is fixed to the housing, while the other end region is attached to the rotor and rotates with it. To prevent the connecting strand from becoming twisted as a result of the rotor rotating relative to the end region of the connecting strand, the connecting strand is additionally guided in a compensating rotor guide device formed as a guide pipe. The guide pipe has rounded U-shaped subsections with side legs of different lengths that can easily expand from one another. The opening of the U is oriented toward the rotation axis of the rotor. The connecting strands start from the fixed end region of the housing and curve outward into one side leg of the U. Within the U-shaped section, the connecting strands are routed around the rotor by a guide pipe. The free end region of the other side leg of the U of the guide pipe is curved back so that it is arranged coaxially with the rotor's rotation axis and directly adjacent to the entrance of the connecting strands into the rotor. The guide pipe is driven in this case at half the rotor rotation speed. Patent Document 3 refers to Patent Document 8 to explain how the use of a rotating guide pipe avoids increased twisting of the connecting strands.

[0008] Further prior art is known from US Pat. No. 5,629,999. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] European Patent Application Publication No. 3936601 [Patent Document 2] European Patent No. 2310486 [Patent Document 3] European Patent No. 2485846 [Patent Document 4] U.S. Patent No. 4,216,770 [Patent Document 5] U.S. Patent No. 4,419,089 [Patent Document 6] U.S. Patent No. 4,389,206 [Patent Document 7] U.S. Patent No. 5,665,048 [Patent Document 8] U.S. Patent No. 3,586,413 [Patent Document 9] European Patent Application Publication No. 1295642 [Non-patent literature]

[0010] [Non-Patent Document 1] www.sartorius.com / en / products / process-filtration / cell-harvesting / ksep-systems (accessed July 6, 2022) Summary of the Invention [Problem to be solved by the invention]

[0011] The problem underlying the present invention is to propose a flow-through centrifuge and a compensating rotor guide device for a flow-through centrifuge which are improved in terms of load and fatigue strength. [Means for solving the problem]

[0012] The object of the present invention is achieved according to the features of the independent claims. Further preferred configurations according to the invention can be found in the dependent claims.

[0013] The present invention relates to a flow-through centrifuge. The flow-through centrifuge comprises a rotor having (at least) one centrifugation chamber. The medium to be centrifuged can be placed in the centrifugation chamber either directly or in a suitable container, and the centrifugation chamber can be purged with another medium, such as a washing solution or a buffer solution. In a flow-through centrifuge, the rotor is rotated around the rotor axis at any rotor speed. The flow-through centrifuge comprises a connecting strand. The connecting strand has a connecting line through which a medium can be supplied to the centrifugation chamber (in particular a container placed in the centrifugation chamber) during operation of the flow-through centrifuge in which the rotor rotates. The connecting strand further has a connecting line through which a medium can be discharged from the centrifugation chamber (in particular a container placed in the centrifugation chamber). Depending on the current operating phase, the flow direction through the connecting line can be reversed. One end region of the connecting strand is fixed to the housing, while the other end region of the connecting strand rotates together with the rotor. To prevent twisting of the connecting strand, the connecting strand is rotated together with the compensating rotor and is guided in a compensating rotor guide device of the compensating rotor, in particular in a guide pipe. The compensating rotor and the compensating rotor guide device are rotated about the rotor axis at half the rotor speed. In this respect, the flow-through centrifuge can be configured similarly to the prior art flow-through centrifuges described at the beginning, for example.

[0014] In conventional flow-through centrifuges, the connecting strand consists of a flexible pipe or tube (preferably a corrugated pipe) through which the connecting lines extend. The cost of such a connecting strand, including the connecting lines and the interface to the rotor, on the one hand, and the media network, on the other, can easily be in the range of 5,000 to 15,000 euros. As a result of the high load on the connecting strand during operation of the flow-through centrifuge, the connecting strand may need to be replaced after 5 to 20 hours of operation, which, on the one hand, leads to high retooling times and downtime of the flow-through centrifuge, and, on the other hand, causes considerable costs. According to the prior art, such a short lifespan of the connecting strand is usually accepted, since it is not possible to extend the operating time of the connecting strand by reducing the rotor speed or by dimensioning the connecting strand more strongly and / or by selecting a high-strength material for the connecting strand.

[0015] The present invention is based primarily on an investigation of the loads acting on the connecting strands during operation of a flow-through centrifuge. The investigations underlying the present invention led to the conclusion that the connecting strands in a flow-through centrifuge are subjected to complex loads.

[0016] a) The connecting strands undergo a relative rotational movement about the longitudinal axis within the compensating rotor guide device. This relative rotational movement leads to friction between the connecting strands and the compensating rotor guide device. This friction leads to torsional loads on the connecting strands that vary over their longitudinal sections. Furthermore, friction between the connecting strands and the inner wall of the compensating rotor guide device leads to heat input into the connecting strands in the region of the contact and friction surfaces, and possibly to wear.

[0017] b) The connecting strands are guided in the compensating rotor guide device so that they curve outward from the end region of the housing fixture and its coaxial arrangement with the rotor axis, following the first guide profile section of the compensating rotor guide device. From the inflection point, the connecting strands then curve in the opposite direction in the second guide profile section of the compensating rotor guide device until they can be guided past the rotor so that the connecting strand is located radially outward with a section oriented parallel to the rotor axis. The connecting strands are thereby guided in the designated guide profile section according to an elongated S, with both ends of S oriented parallel to each other and one end arranged coaxially with the rotor axis, while the other end has the greatest distance from the rotor axis of the connecting strand. The connecting strands are curved in the compensating rotor guide device according to the guide profile of the designated guide profile section, and thus the connecting strands are bent from their initial elongated position.

[0018] The mechanical boundary conditions of the connecting strands, i.e., Attaching one end region of the connecting strand to a stationary housing; Attaching the other end region of the connecting strand to the rotor rotating at the rotor speed and Guiding of the connecting strands in a compensating rotor guide device rotated at half the rotor speed; As a result, the bending of the connecting strand is not static, but exhibits rotational bending. Beyond the (imaginary) neutral axis, as a result of rotational bending, the material regions of the connecting strand, in particular of the flexible tube or flexible (corrugated) pipe, which are each temporarily located radially outward, are exposed to alternating, harmonic progressions of alternating stresses, i.e., alternating tensile and compressive stresses.

[0019] c) When the connecting strands comprise corrugated pipes, the rotational bending of the corrugated pipes can cause the waves or ribs of the corrugated pipes to abut against each other on the radially inner side of the curved guide profile, which can lead to non-linearities in the stiffness of the corrugated pipes, which can result in modified loading mechanisms of the corrugated pipes.

[0020] d) The considerations underlying the present invention have led to the conclusion that the longitudinal sections of the connecting strands (in particular the tubes or (corrugated) pipes and the conduits arranged therein) and also the medium arranged in the conduits are subjected to centrifugal forces whose amount depends on the distance of each longitudinal section from the rotor axis. The centrifugal force acting on each longitudinal section is then: a first component acting in the direction of the guide surface of the compensating rotor guide device and thus increasing the clamping force and friction between the connecting strand and the compensating rotor guide device; a second component oriented in the longitudinal direction of the connecting strand and resulting in a tensile or compressive force in the longitudinal direction of the connecting strand; It has the following characteristics.

[0021] The division of the centrifugal force into both components is obtained from trigonometric functions as a function of the angle at which the longitudinal section is inclined relative to the rotor axis.

[0022] In the first guide profile section, the second component leads to a tensile force which results in an elongation of the connecting strand, whereas in the second guide profile section, this second component leads to a compressive force which compresses the connecting strand.

[0023] In this case, the tensile force as a result of the centrifugal force in the first material region of the connecting strand at a first longitudinal extension coordinate of the connecting strand with a small distance from the rotor axis may be greater than the tensile force as a result of the centrifugal force in the second material region of the connecting strand at a second longitudinal extension coordinate of the connecting strand with a larger distance from the rotor axis, since a longer section of the connecting strand is arranged radially outside the first material region of the connecting strand at the first longitudinal extension coordinate of the connecting strand, and this longer section may lead to a greater tensile force as a result of the centrifugal force.

[0024] e) Depending on the applied loads, modified boundary conditions may arise within the connecting strands. Thus, for example, elongation of a connecting line within a tube or (corrugated) pipe may lead to the connecting line no longer abutting the inner surface of the tube or (corrugated) pipe, thereby no longer providing support inside the tube or (corrugated) pipe, and the friction inside the connecting strand may change. This may also change the longitudinal and / or bending stiffness of the connecting strand.

[0025] f) The possible elasticity of the medium in the lines of the connecting strands may have further significance, since centrifugal forces may, as a result of this elasticity, lead to pressure changes inside the connecting lines and thus to altered mass distribution and / or stiffness changes.

[0026] Based on these considerations, the investigation of the loads on the connecting strands described above, and the experiments underlying the present invention, the present invention proposes to use a compensating rotor guide device in a flow-through centrifuge, the compensating rotor guide device having a guide contour whose radius of curvature for a first distance from the rotor axis is greater than the radius of curvature for a second distance from the rotor axis, the first distance being smaller than the second distance.

[0027] This is explained by a simplified, non-limiting example in which the guide profile is formed according to a horizontally elongated S and has a lower left end region oriented coaxially with the rotor axis and an upper right end region oriented parallel to the rotor axis. An inflection point is present midway between these end regions, and in the region of the inflection point the curvature changes sign in a mathematical sense. In this simplified example, in the first guide profile section between the lower left end region and the inflection point, the radius of curvature is constant according to a first radius of curvature, while in the second guide profile section between the inflection point and the upper right end region, the radius of curvature is constant according to a second radius of curvature, which is smaller than the first radius of curvature.

[0028] As a result of the rotational bending, the cross section in the respective longitudinal coordinate of the first guide profile section is subjected to a rotational bending stress, which may be constant in amount over the longitudinal section of the first guide profile section but changes sign in a harmonic progression as a function of the rotation. This rotational bending stress is superimposed by a tensile stress, which arises as a result of the mass of the connecting strands as a result of centrifugal forces and depends on the distance from the rotor axis and which depends on the square of the rotational frequency. A centrifugal force acts on the first end of the first guide profile section, where the bending begins starting from a coaxial orientation with respect to the rotor axis, and which is generated by the entire connecting strand subsection in the first guide profile section and, if applicable, by a subsection in the second guide profile section. The tensile force acting in the longitudinal cross-section as a result of centrifugal force decreases with respect to the longitudinal coordinate of the first guide profile section that is spaced farther from the rotor axis, so that the tensile force and resulting tensile stress are greatest at the first end. In each longitudinal cross-section, a superposition of rotational bending stress and tensile stress resulting from centrifugal force occurs. When rotational bending temporarily leads to rotational bending compressive stress, the superposition of the tensile stress resulting from centrifugal force results in a reduction in the resultant stress, which is favorable for material loads. However, in this case, a short time later, rotational bending tensile stress is also applied to the same cross-sectional area due to further rotational bending. The superposition of the tensile stress resulting from centrifugal force with the rotational bending tensile stress results in the sum of the amount of rotational bending tensile stress and the amount of tensile stress resulting from centrifugal force. This results in an increased maximum value of synthetic stress, which may be significant for elucidation experiments that may be performed regarding the limit of the lifespan of the connecting strands.

[0029] By means of the configuration according to the invention, the maximum combined load can be reduced, and thus the service life can be improved (possibly significantly): In the region of the rotor axis or adjacent to this region, the radius of curvature is selected to be larger according to the invention. By increasing the radius of curvature, the amplitude of the rotational bending stresses is reduced, which in this case, despite the above-mentioned superposition with tensile stresses as a result of centrifugal forces, can lead to a reduction in the maximum resultant stress and therefore a reduction in the load.

[0030] According to the present invention, the guide profile has a first guide profile section and a second guide profile section. In the aforementioned example, the guide profile sections can each be quadrant-shaped and have opposite curvatures, in which case the guide profile sections each have a different radius. However, it is also possible that within at least one guide profile section, there are several guide profile subsections each having a different radius of curvature, where the radius of curvature can vary in steps or continuously. In this proposal of the present invention, the guide profile section has a curvature in a first direction, while the second guide profile section has a curvature in a second direction. The first and second guide profile sections are preferably connected to each other by an intermediate section oriented radially relative to the rotor axis. In the initially described example with quadrant-shaped guide profile sections, the intermediate section can be formed by a local connection of the opposing ends of the guide profile sections, and a straight, preferably radially oriented intermediate section can also extend between these ends. Alternatively or cumulatively, the first guide profile section and the second guide profile section can be connected to each other via an inflection section that switches the sign of curvature. The first guide profile section has a smaller distance from the rotor axis than the second guide profile section. The radius of curvature in the first guide profile section is larger than the radius of curvature in the second guide profile section. To give only a few examples that are not limiting of the invention, the radius of curvature in the first guide profile section can be at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40% or even at least 50% larger than the radius of curvature in the second guide profile section. This means, for example, Only for discrete radii of curvature at specific longitudinal extension coordinates of the guide contour section, A partial section of the guide contour section with a constant radius of curvature, the average radius of curvature in the guide profile section, or For all curvature radii when the curvature radius changes continuously in the guide contour section, This may apply.

[0031] Alternatively or cumulatively, the radius of curvature in the first guide profile section can decrease continuously or in steps in the direction of longitudinal extension and with increasing distance from the rotor axis.

[0032] In principle, within the scope of the present invention, the connecting strands may have any desired configuration. Preferably, the connecting strands have a corrugated pipe through which the various lines of the connecting strands, in particular the connecting lines, extend. The corrugated pipe is used, for example, to bundle, protect, guide and encapsulate the lines.

[0033] As a special proposal of the invention, the radius of curvature of the first guide profile section decreases continuously with increasing distance from the rotor axis. This may apply only to the first guide profile section. Preferably, the radius of curvature of the second guide profile section also decreases continuously with increasing distance from the rotor axis.

[0034] As mentioned above, the loads of the connecting strands in the guide device are very complex, which may also complicate the requirements for the configuration of the geometry of the guide profile sections. In one configuration of a flow-through centrifuge, the radii of curvature in the first guide profile section and / or in the second guide profile section, respectively, at different longitudinal extension coordinates are dimensioned in such a way that the loads of the connecting strands guided in the compensating rotor guide device at these or all longitudinal extension coordinates are constant or vary by no more than ±20%, no more than ±15%, no more than ±10% or no more than ±5%. In this case, the loads that should remain constant or vary only by the indicated percentages are divided into two different partial loads: a tensile load on the connecting strand in the longitudinal extension coordinate resulting from centrifugal forces as a result of the section of the connecting strand being arranged so as to be located radially outside the longitudinal extension coordinate; a rotational bending load of the connecting strand in the longitudinal coordinate, which results from the rotational bending of the connecting strand and corresponds to the curvature of the connecting strand; It can be obtained by superposition of

[0035] This design is based on the assumption that both of the mentioned partial loads are crucial for the strength of the connecting strand, and the range of percentage variations given allows for safety considerations on the one hand and for the additional loads that occur (friction, heating, wear, etc.) on the other hand.

[0036] For alternative or cumulative design criteria, the curvature radius is dimensioned so that the load resulting from both of the aforementioned partial loads over the longitudinal section of the connecting strand in the first guide profile section and / or in the second guide profile section is less than the allowable load of the connecting strand by at least a predetermined percentage. Thus, for example, for the use of a corrugated pipe in the connecting strand, the maximum static bending load may be predetermined by the manufacturer, so that in this case the resultant stress determined from both partial loads is less than this bending load provided by the manufacturer by a fixed, predetermined percentage. Another allowable load, which defines a percentage relationship to the load determined using these partial loads, can be the maximum dynamic tensile and / or bending stress or a predetermined tensile or fatigue strength of the connecting strand component or of the entire connecting strand.

[0037] A further solution to the problem underlying the present invention provides a compensated rotor guide device, specifically for a flow-through centrifuge as described above. The compensated rotor guide device comprises or is a guide pipe having a guide profile, the guide profile having a first guide profile section and a second guide profile section. The first guide profile section has a curvature in a first direction, while the second guide profile section has a curvature in a second direction oriented opposite to the first direction. The first and second guide profile sections are preferably connected to each other by an intermediate section or an inflection section oriented radially relative to the rotor axis. The first guide profile section has a smaller distance from the rotor axis than the second guide profile section. The radius of curvature of the first guide profile section is greater than the radius of curvature of the second guide profile section. In the guide pipe, the radius of curvature in the first guide profile section can decrease in the direction of the end region facing the second guide profile section, which can be done in steps or continuously.

[0038] Advantageous developments of the invention can be seen from the claims, the description and the drawings.

[0039] The advantages listed in the specification of features and combinations of features are merely examples, and these advantages are not necessarily achieved by an embodiment according to the invention, but may act alternatively or cumulatively.

[0040] With respect to the disclosure of the original application and patent, the following applies, except to the scope of protection: further features, in particular the geometric shapes shown and the relative dimensions of the various components to one another, as well as their relative arrangement and interaction, can be seen in the drawings. Combinations of features of different embodiments of the invention or of features of different claims are likewise possible and are hereby envisaged apart from the selected references in the claims. This also relates to features shown in different drawings or mentioned in their descriptions. These features may also be combined with features of different claims. Likewise, features recited in the claims may be omitted for the sake of another embodiment of the invention, but this does not apply to the independent claims of the granted patent.

[0041] Features recited in the claims and the specification should be understood as being present in exactly that number or in a greater number than the recited number, without the need to explicitly use the adverb "at least" in relation to the number. That is, for example, when referring to one element, this should be understood as meaning that there is exactly one element, two elements, or more elements. Features recited in the claims may be supplemented by further features or may be a single feature possessed by the subject matter of each claim.

[0042] The reference numerals in the claims do not limit the scope of the subject matter protected by the claims, but are used solely to facilitate the understanding of the claims.

[0043] The present invention will be further explained and illustrated below with reference to preferred embodiments shown in the drawings. [Brief explanation of the drawings]

[0044] [Figure 1] 1 is a highly schematic, three-dimensional, half-section longitudinal section of a flow-through centrifuge with connecting strands (without showing the guide device); FIG. [Figure 2]FIG. 2 shows a connecting strand in a guide device such as can be used in the flow-through centrifuge shown in FIG. 1. [Figure 3] 10 is a table relating to the setting of the curvature radius of the guide pipe of the compensating rotor guide device. [Figure 4] 10 is a table relating to the setting of the curvature radius of the guide pipe of the compensating rotor guide device. [Figure 5] 10 is a table relating to the setting of the curvature radius of the guide pipe of the compensating rotor guide device. [Figure 6] 4 shows an exemplary progression of the radius of curvature of the guide pipe of the compensating rotor guide device and the resulting pulling force due to the centrifugal force as a function of the distance from the rotor axis; FIG. [Figure 7] FIG. 1 is a schematic diagram to aid in the discussion of determining the tensile forces acting on the pipes or tubes of the connecting strands in a longitudinal section in the longitudinal extension coordinate and spaced from the rotor axis as a result of centrifugal forces. DETAILED DESCRIPTION OF THE INVENTION

[0045] In the figures, corresponding or similar components or features are in part designated by the same reference numerals, and these components or features may then be distinguished from one another by the addition of the letters a, b, .... In this case, the components or features may be associated with or without the addition of the letters, and thus reference may be made to one, several or all of the components or features.

[0046] FIG. 1 shows a highly schematic, three-dimensional half-section longitudinal section of a flow-through centrifuge 1. The flow-through centrifuge 1 comprises a housing 2 and, in particular, a can 3 having a wall 4. The wall 4 of the can 3 defines a rotor chamber 5, in which a rotor 6 is rotated about a rotor axis 7 at a given rotor speed. Of the rotor 6, the schematic view shown in FIG. 1 shows only containers 8a, 8b (here, two containers 8a, 8b; however, any other number of containers 8 may also be present) arranged in the centrifugation chamber of the rotor 6. The containers 8a, 8b may be, for example, blood bags 9 or any other container. The containers 8 are uniformly distributed around the rotor axis 7 and have the same distance therefrom.

[0047] The flow-through centrifuge 1 includes a rotor chamber thermoregulation circuit 10, of which only the rotor chamber thermoregulation loop 11 is shown in Figure 1. The rotor chamber thermoregulation loop 11 is integrated into the wall 4 of the can 3 and wraps around the rotor axis 7 and the rotor chamber 5 with multiple turns.

[0048] Also visible in FIG. 1 is a connecting strand 12. The connecting strand 12 comprises a flexible tube or flexible pipe 13, which is in particular a corrugated pipe. A temperature-regulated supply line 14 and a temperature-regulated discharge line 15 optionally extend through the tube or pipe 13 and can be used for temperature regulation and cooling of the connecting strand. Two connecting lines 16, 17 extend through the tube or pipe 13, which are passed through by a medium in different directions during different operating phases of the centrifugation process. At one end region 18, the connecting strand 12 is attached to the wall 4 of the housing 2 or can 3, while at the other end region 19, the connecting strand 12 is attached to the rotor 6 and rotates therewith.

[0049] The compensating rotor also rotates around the rotor axis 7, with its rotation speed being half that of the rotor 6. The compensating rotor has a compensating rotor guide device 20, which is shown in FIG. 2 and is here formed as a guide pipe 21. The guide pipe 21 has two guide pipe halves 22, 23, which are separated from each other by an imaginary dividing line 24, shown by a dashed line. The guide pipe 21 has a constant circular cross section along a longitudinal extension coordinate 25, which is curved in various directions, as will be explained in more detail below. The connecting strand 12 extends through the guide pipe 21, here formed as a corrugated pipe. In the end regions of the guide pipe 21, the connecting strand 12 extends out from the guide pipe 21 to enable the connecting strand 12 to be attached to the housing 2 or the rotor 6. There is radial play between the inner surface 26 of the guide pipe 21 and the circumferential surface of the connecting strand 12, and depending on the curvature of the connecting strand 12 and the aforementioned load on the connecting strand 12, the connecting strand 12 may abut against the inner surface 26 of the guide pipe 21 on one side.

[0050] Within the guide pipe half 22, the guide pipe 21 has a guide contour 27, which is formed by an inner surface 26. The guide contour 27 comprises a first guide contour section 28 and a second guide contour section 29, which are directly connected to one another via an inflection section 30. In this embodiment, the inflection section 30 simultaneously forms an intermediate section 31, in the region of which the guide pipe 21 is oriented radially relative to the rotor axis 7. In the first guide contour section 28, the guide contour 27, in particular the longitudinal extension 25 of the guide pipe 21, has a first radius of curvature 32, whereas in the second guide contour section 29, the guide contour 27 has a second radius of curvature 33. 2, the first radius of curvature 32 in the first guide section 28 is constant, and the second radius of curvature 33 in the second guide section 29 is also constant, with the second radius of curvature 33 being smaller than the first radius of curvature 32. In the first guide profile section 28, the curvature of the longitudinal extension coordinate 25 is counterclockwise, whereas the curvature of the longitudinal extension coordinate 25 is reversed in the inflection section 30, so that in the second guide profile section 29, the curvature of the longitudinal extension coordinate 25 extends clockwise. The guide profile sections 28, 29 each extend over a circumferential angle of 90°. However, smaller circumferential angles are also possible, so that in this case the guide pipe 21 is not oriented radially relative to the rotor axis 7 in the inflection section 30.

[0051] 2, one end region 34 of the first guide profile section 28 is oriented (approximately) coaxially with respect to the rotor axis 7, whereas the other end region 35 of the first guide profile section 28 is oriented radially with respect to the rotor axis 7. In the inflection section 30 and the intermediate section 31, the end region 35 is flush with the facing end region 36 of the second guide profile section 29, which end region 36 is also oriented radially with respect to the rotor axis 7. In contrast, the other end region 37 of the second guide profile section 29 is oriented parallel to the rotor axis 7, and in this region the guide pipe 21 has the greatest distance from the rotor axis 7. Essentially, the second guide pipe half 23 can be shaped mirror-symmetrically with respect to the dividing line 24 of the first guide pipe half 22. In the illustrated embodiment, this mirror symmetry applies only to the second guide profile section 29', whereas the first guide profile section 28' in the second guide pipe half 23 is not mirror symmetrical and is joined to the second guide profile half 29', so that in the direction of the longitudinal extension coordinate 25, both guide profile sections 28', 29' are curved clockwise and together form a half ring which has a radius of curvature 32' that expands in the direction of the longitudinal extension coordinate 25 in the region of the inflection section 30' and the intermediate section 31'.

[0052] 2, the guide pipe 21 can thus consist of two identical, combined guide profile parts forming the guide profile sections 29, 29' respectively, and two guide pipe parts forming the guide profile sections 28, 28', which can potentially increase the proportion of identical parts required for the manufacture of the guide pipe 21. However, it is self-evident that, depending on the manufacturing method used, it is also possible to manufacture the guide pipe 21 from one piece.

[0053] The guide profile sections 28, 29 shown in FIG. 2 are shown and described for illustrative purposes only and are not intended to be limiting of the present invention.

[0054] As a first suggestion, unlike in Figure 2, the radius of curvature 32 in the guide profile section 28 is not constant, but rather decreases along the longitudinal extension coordinate 25 in a stepped or unstepped manner.

[0055] First, the radius of curvature 32 may decrease continuously (eg, only adjacent the end 34) and then remain constant in the guide profile section 28 or may decrease further in a stepped manner.

[0056] For all embodiments, a constant radius of curvature 33 may then be used in the second guide contour section 29, or a stepped decreasing radius of curvature 33 may be used, or a radius of curvature 33 that decreases continuously in some subsections and is constant or changes in steps in some other subsections.

[0057] In the following, one exemplary possibility for determining the extension of the curvature radii 32, 33 of the guide pipe 21 of the compensating rotor guide device 20 is described. A simplified calculation with simplifying assumptions is described here, without limiting the invention to the curvature radii determined in this way. For the following exemplary calculation, it is assumed that the tube or (corrugated) pipe 13 follows the extension of the guide contour 27 of the guide pipe 21. As can be seen in FIG. 2, this is not the case in practice, so for a calculation with increased accuracy, the extension of the tube or (corrugated) pipe 13 in the guide pipe 21 must be determined and then the curvature radii must be calculated accordingly for this extension.

[0058] For the purposes of the exemplary calculation, a tube or (corrugated) pipe 13 is used as a base, having a diameter D of 0.013 m and a spring constant c=5,000 [tensile force (unit: N) / elongation] when subjected to a tensile force acting in the longitudinal direction. This spring constant c can be provided by the manufacturer or determined via a simple tensile test.

[0059] The table in FIG. 3 shows different tensile forces F acting on the tube or (corrugated) pipe 13 in the range of 0N to 330N. Zug Regarding the elongation D obtained from the spring constant c of the tube or (corrugated) pipe 13, Zugkraft D Zugkraft =F Zug / c are calculated (see columns 1 and 2).

[0060] When a tube or pipe is bent through a radius of curvature R, the material area located on the outer side of the bend is stretched, while the material area located on the inner side is compressed. The elongation D of the outer radial area as a result of bending is Biegung teeth, D Biegung =0.5D / (R+0.5D) can be found via

[0061] In the table of FIG. 3, the fourth row shows the elongation D resulting from bending for each radius of curvature R in the range of 0.45 m to 0.175 m shown in the second row. Biegung is displayed.

[0062] The elongation D as a result of bending in the area of the material that is elongated most as a result of bending during operation Biegung and the elongation D as a result of the pulling force Zugkraft When the superposition of the two is carried out, in the table of FIG. 3, on the one hand, the elongation D as a result of the tensile force Zugkraft and the elongation D for pure bending Biegungand must be added together, and from this we can see that the composite elongation D resultierend occurs.

[0063] Resultant stretch D resulting from overlap resultierend If the design of the radius of curvature R should be carried out so that the composite elongation D is always less than 12%, then resultierend Only the radius of curvature R at this time is taken into consideration. resultierend To make it less than 12%, When the pulling force is between 0N and 60N (i.e., at a longitudinal extension coordinate 25 far away from the rotor axis 7, preferably where the guide pipe 21 is oriented parallel to the rotor axis 7 and thus where no centrifugal force acts), the radius of curvature R can be 0.055m; When the pulling force is 90N to 120N, the radius of curvature R can be 0.065m; When the pulling force is 150N to 180N, the radius of curvature R can be 0.075m; When the pulling force is 210N to 240N, the radius of curvature R can be 0.085m; When the pulling force is 270 N, the radius of curvature R can be 0.095 m; When the pulling force is 300 N, the radius of curvature R can be 0.105 m; When the pulling force is 330 N (this pulling force occurs, for example, at the longitudinal extension coordinate 25 of the guide pipe 21 in the guide profile section 8 in the end region 34), the radius of curvature R can be 0.115 m. This is the result obtained.

[0064] (Corresponding calculations may be performed in which the pulling force is changed in smaller increments or continuously.)

[0065] 4 lists in the first column the length of the guide pipe 21 along the longitudinal extension coordinate 25 from the rotor axis 7, in the range of 0 m to 0.21 m, which corresponds to the length to the dividing line 24. In the second column, the angle 43 in radians is listed for any longitudinal section of the connecting strand 12 located at the longitudinal extension coordinate 25 relative to the rotor axis 7. At the longitudinal extension coordinate 0.00 m, i.e., at the entrance to the guide pipe 21, the angle 43 is π / 2, whereas the angle 43 is zero in the inflection section 30 and −π / 2 in the end region 37.

[0066] If we simplify by assuming that both guide profile sections 28, 29 are quadrant-curved with the same radius of curvature R, then between these characteristic angles 43 with respect to their respective longitudinal extension coordinates 25, the angle 43 is: Angle 43=π / 2-(π / 2×Longitudinal extension coordinate 25 / R) where the radius of curvature R is assumed to be constant and equal to 0.105 m.

[0067] The spacing A of any longitudinal section in the longitudinal extension coordinate 25 is then: A=R(1-sin(angle 43)) where the spacing A is shown in the third column of FIG.

[0068] For example, the relative mass m of the connecting strand 12 per unit length r But, m r = 0.3705 kg / m, the absolute centripetal acceleration a z The relative axial accelerations in the respective longitudinal coordinates 25, obtained from the quotient of the acceleration of gravity g and the axial acceleration g, are given by: a z / g=(2πn) 2 A / g where n is the rotational speed of the compensating rotor guide device 20, which for an exemplary calculation is 36.67 revolutions per second (2200 revolutions per minute), and g=9.813 m / s 2 is established.

[0069] Opposing central acceleration a z / g, relative mass m r and multiplied by the length of the longitudinal section ΔL, where ΔL=0.01 m, we obtain the value displayed in column 5 of Figure 4, which displays the centrifugal force acting on this longitudinal section with respect to its length ΔL.

[0070] 4, it is necessary to calculate the tensile force acting at the longitudinal extension coordinate 25, which is displayed in the last column of the table in FIG. 4, by multiplying the value assigned in the fifth column by g (starting from the radially outermost longitudinal section at the longitudinal extension coordinate 25 of 0.21 m), and multiply this result by the cosine of the angle 43, which is displayed in the second column of the table in FIG. 4, since only the component due to the cosine of the angle 43 contributes to the tensile force acting in the direction of the longitudinal extension coordinate 25. With the transition to the next adjacent longitudinal section 25, which is located radially inward, the previously determined tensile force must be added to the tensile force calculated for this other longitudinal section 25 with respect to the changed angle and changed longitudinal extension coordinate 25. In the last row, the tensile force components of the individual longitudinal sections which are arranged radially outwardly in the direction of the longitudinal extension coordinate 25 are summed.

[0071] The tensile force determined in the last column of FIG. 4 for each longitudinal extension coordinate 25 is also entered in column 2 of FIG. 5. In the third column, the resulting elongation D Zugkraft Corresponding to FIG. 3, the following columns then show the elongation D as a result of bending for various radii of curvature R. Biegung and the elongation D as a result of the pulling force Zugkraft The resulting composite elongation D with respect to the superposition with resultierend has been calculated.

[0072] Again, the synthetic elongation D resultierend When designing to keep the elongation of the curve to less than 12%, the radius of curvature R is determined by the resultant elongation D shown in bold in Figure 5. resultierend This means that When the longitudinal extension coordinate 25 is within a range of 0.0 m to 0.05 m, the radius of curvature R may be 0.115 m; When the longitudinal extension coordinate 25 is within a range of 0.06 m to 0.09 m, the radius of curvature R may be 0.105 m; When the longitudinal extension coordinate 25 is within a range of 0.10 m to 0.11 m, the radius of curvature R may be 0.095 m; When the longitudinal extension coordinate 25 is within a range of 0.12 m to 0.14 m, the radius of curvature R may be 0.085 m; When the longitudinal extension coordinate 25 is within a range of 0.15 m to 0.16 m, the radius of curvature R may be 0.075 m; When the longitudinal extension coordinate 25 is within the range of 0.17 m to 0.18 m, the radius of curvature R may be 0.065 m; and When the longitudinal extension coordinate 25 is within the range of 0.19 m to 0.21 m, the radius of curvature R may be 0.55 m. This means that...

[0073] A more detailed or continuous calculation of the longitudinal extension coordinate 25 may be performed. Avoidance of overstretching may also be performed when a larger radius of curvature than those listed above for each longitudinal extension coordinate 25 is used.

[0074] 6 shows, on the one hand, the resulting and acting tensile forces 39 (see solid lines determined via spline approximation of the determined individual tensile forces) as a function of the coordinate 38 of the longitudinal extension 25 of the guide pipe 21 or of the tube or (corrugated) pipe 13. On the other hand, it shows the resultant elongation D resultierendshould be at most 12%.

[0075] As explained above, the calculation method and the curve extension shown in Figure 6 are shown only by way of example, and simplifying and possibly distorting assumptions are made here. As also mentioned above, the actually used radius of curvature R may be constant in the partial sections, in contrast to the table or Figure 6, provided that the radius of curvature R in the partial sections adjacent to the rotor axis 7 is greater than the radius of curvature R in the partial sections further away from the rotor axis 7, in particular in the guide profile section 28 on the one hand and in the guide profile section 29 on the other hand. A stepped or arbitrarily differently adapted progression of the radius of curvature R gradually following the curve extension shown in Figure 6 may also be used.

[0076] 7 shows a highly simplified schematic diagram (for example, ignoring friction between the connecting strand 12 and the tube or pipe 13 and radially outward support of the tube or pipe 13) to aid in discussion. In this case, the connecting strand 12 (particularly the tube or pipe 13 and / or the pipelines 14, 15, 16, 17) is divided into a number of longitudinal sections 41 of the same size, which are distinguished from one another by the auxiliary symbols "-1", "-2". These longitudinal sections 41, which have the same size and therefore the same mass Δm, respectively have different distances A1, A2, ... from the rotor axis 7, which distances A1, A2, ... are indicated in FIG. 7 by the reference numeral 42 and are also distinguished from one another by the auxiliary symbols "-1", "-2", .... For each longitudinal section 41, the centrifugal acceleration a z acts on it, and the centrifugal acceleration a z Regarding a z =(2πn) 2 A where A is the distance 42 of each of the longitudinal sections 41 from the rotor axis 7, and n is the rotation speed [s -1The centrifugal force F acting on the longitudinal section 41 is z In this case, F z =Δma z It is obtained via.

[0077] For each longitudinal section 41, the centrifugal force F z leads to a tensile force acting in the direction of the longitudinal extension coordinate only with a force component that depends on the angle 43 with respect to the respective longitudinal extension coordinate.

[0078] With respect to the first longitudinal section 41-1, which is arranged coaxially with respect to the rotor axis 7, the simplified observation chosen here is that the pulling force F acting on the longitudinal section 41-1 is Zug,1 arises from the sum of the centrifugal forces that must be maintained by the longitudinal section 41-1, i.e. from the sum of the force components of the centrifugal forces acting on the longitudinal sections 41-2, 41-3, ..., acting in the direction of the longitudinal extension coordinate 25. This results in the tensile force F acting on the longitudinal section 41-1 Zug,1 Regarding F Zug,1 =Δm4π 2 n 2 (C2A2+C3A3+C4A4+...) holds true, whereas for the next longitudinal section 41-2, the tensile force F Zug,2 is calculated as follows: F Zug,2 =Δm4π 2 n 2 (C3A3+C4A4+...) Same as below.

[0079] Here, C represents, on the one hand, the conversion of the centrifugal force acting on the longitudinal section 41 into a force component acting in the direction of the longitudinal extension coordinate 25. Furthermore, in C, other correction factors can be taken into account, for example correction factors resulting from taking friction into account. From the above simplified observation, the acting tensile force F Zugis greatest in the longitudinal section 41-1, and as the distance of the longitudinal section 41 from the rotor axis 7 increases, the acting tensile force, and therefore the load, decreases.

[0080] In some cases, more accurate modeling of the acting loads may be performed. The qualitative statement remains that an increase in fatigue strength can be achieved by increasing the radius of curvature for the longitudinal section 41 adjacent the rotor axis 7. [Explanation of symbols]

[0081] 1 Flow-through centrifuge 2. Housing 3 cans 4. Wall 5 Rotor chamber 6 rotors 7 Rotor axis 8 containers 9 Blood Bags 10 Rotor chamber temperature control circuit 11. Rotor chamber temperature control loop 12 connecting strands 13 Tubes and pipes 14 Temperature control supply line 15 Temperature control discharge pipe 16 Connecting pipeline 17 Connecting Pipes 18 End area 19 End area 20 Compensating rotor guide device 21 Guide pipe 22 Guide pipe half 23 Guide pipe half 24 Dividing Line 25 Longitudinal extension coordinate 26 Inner 27 Guide Contour 28 First Guide Contour Section 29 Second Guide Contour Section 30 Inflection Section 31 Middle Section 32 First radius of curvature 33 Second radius of curvature 34 End area 35 End area 36 End area 37 End area 38 interval 39 Pulling force 40 radius of curvature 41 Longitudinal Section 42 interval 43 angle

Claims

1. A flow-through centrifuge (1), comprising: a) a rotor (6) having a centrifugal chamber, the rotor (6) being rotatable about a rotor axis (7) at any rotor speed; b) a connecting strand (12) having connecting lines (16; 17) through which a medium can be supplied to the centrifugation chamber and connecting lines (17; 16) through which a medium can be discharged from the centrifugation chamber during operation of the flow-through centrifuge (1) with the rotor (6) rotating, c) one end region (18) of the connecting strand (12) is arranged fixedly in the housing, and the other end region (19) of the connecting strand (12) is rotated together with the rotor (6); d) in order to avoid twisting of the connecting strands (12), the connecting strands (12) are guided in a compensating rotor guide device (20), which is rotated about the rotor axis (7) at half the rotor speed; e) the compensating rotor guide device (20) has a guide contour (27), the radius of curvature (32) of the guide contour (27) for a first distance from the rotor axis (7) being greater than the radius of curvature (33) for a second distance from the rotor axis (7), the first distance being smaller than the second distance; f) the guide profile (27) comprises a first guide profile section (28) and a second guide profile section (29); g) the first guide profile section (28) has a curvature in a first direction and the second guide profile section (29) has a curvature in a second direction; h) the first guide profile section (28) and the second guide profile section (29) are preferably connected to each other by an intermediate section (31) or an inflection section (30) oriented radially relative to the rotor axis (7); i) the first guide profile section (28) has a smaller spacing from the rotor axis (7) than the second guide profile section (29); In a flow-through centrifuge (1), j) the radius of curvature (32) of the first guide profile section (28) is greater than the radius of curvature (33) of the second guide profile section (29), and preferably the radius of curvature (32) of the first guide profile section (28) decreases with increasing distance from the rotor axis (7) in the direction of the longitudinal extension coordinate (25); A flow-through centrifuge (1) characterized by:

2. 2. A flow-through centrifuge (1) according to claim 1, characterized in that the connecting strands (12) comprise corrugated pipes.

3. 3. A flow-through centrifuge (1) according to claim 1 or 2, characterized in that the radius of curvature (32) of the first guide profile section (28) and / or the radius of curvature (33) of the second guide profile section (29) become successively smaller with increasing distance from the rotor axis (7).

4. In the first guide profile section (28) and / or in the second guide profile section (29), the radii of curvature (32; 33) at different or all longitudinal extension coordinates (25) are: a) tensile loads of the connecting strands (12) at their respective longitudinal coordinates (25) resulting from centrifugal forces caused by longitudinal sections of the connecting strands (12) arranged so as to be located radially outside of the respective longitudinal coordinates (25); b) the rotational bending load of the connecting strand (12) in each longitudinal coordinate (25) resulting from the rotational bending of the connecting strand (12) as a function of the radius of curvature (32; 33); so that the load on the connecting strand (12) guided in the compensating rotor guide device (20) in a longitudinally extending coordinate (25) as a result of the superposition of is constant over the longitudinal section or varies by no more than ±20%, no more than ±15%, no more than ±10% or no more than ±5%; The dimensions are set, 4. The flow-through centrifuge according to claim 3, characterized in that

5. In the first guide profile section (28) and / or in the second guide profile section (29), the radii of curvature (32; 33) at different or all longitudinal extension coordinates (25) are: a) tensile loads of the connecting strands (12) at their respective longitudinal coordinates (25) resulting from centrifugal forces caused by longitudinal sections of the connecting strands (12) arranged so as to be located radially outside of the respective longitudinal coordinates (25); b) the rotational bending loads of the connecting strands (12) in the respective longitudinal coordinates that arise as a result of the rotational bending of the connecting strands (12) as a function of the radii of curvature (32; 33); the load on the connecting strand (12) guided in the compensating rotor guide device (20) in the longitudinal extension coordinate (25) as a result of the superposition of the above is at least a predetermined percentage less than the allowable load of the connecting strand (12), The dimensions are set, A flow-through centrifuge (1) according to claim 3 or 4, characterized in that

6. A compensating rotor guide device (20) for a flow-through centrifuge (1) with a guide pipe (21) according to any one of claims 1 to 5, comprising: The guide pipe (21) has a guide profile (27), the guide profile (27) having a first guide profile section (28) and a second guide profile section (29); a) the first guide profile section (28) has a curvature in a first direction and the second guide profile section (29) has a curvature in a second direction; b) the first guide profile section (28) and the second guide profile section (29) are preferably connected to each other by an intermediate section (32) or an inflection section (30) oriented radially relative to the rotor axis (7); c) the first guide profile section (28) has a smaller spacing from the rotor axis (7) than the second guide profile section (29); d) the radius of curvature (32) of the first guide profile section (28) is greater than the radius of curvature (33) of the second guide profile section (29), and preferably the radius of curvature (32) of the first guide profile section (28) decreases in the direction of the end region (35) facing the second guide profile section (29); A compensating rotor guide device (20) for a flow-through centrifuge (1).

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