Flow-through centrifuge and compensation rotor guide

Abstract

The invention relates to a flow-through centrifuge comprising a rotor which has at least one centrifugal chamber and which rotates about a rotor axis (7) at a rotor speed. The flow-through centrifuge has a connection line (12), and a connection line (16; 17) extends through the connection line. When the flow-through centrifuge is operated with the rotor rotating, the medium passes through the connecting line (16; 17) can be supplied to the centrifugal chamber and can be discharged from the centrifugal chamber. One end region (18) of the connecting line (12) is fixedly arranged on the housing and the other end region (19) of the connecting line (12) is twisted with the rotor. In order to avoid twisting of the connecting line (12), the connecting line (12) is guided in a compensating rotor guide (20), in particular a guide tube (21), which is twisted about the rotor axis (7) by half of the rotor speed. According to the invention, the compensating rotor guide (20) has a guide contour (27), the curvature (32) of which in a first guide contour section (28) is greater than the curvature (33) in a second guide contour section (29). Therefore, the service life of the connecting line (12) can be prolonged.

Description

Technical Field

[0001] The invention relates to a flow-through centrifuge in which at least one medium, in particular a fluid, a liquid, a suspension, etc., is at least temporarily supplied to a centrifuge chamber and / or is discharged from the centrifuge chamber during the rotation of the centrifuge chamber. The medium can be arranged in a container in the centrifuge chamber. The at least one medium is in particular a medium to be centrifuged, a flushing liquid, a washing or buffer solution, a modified medium extracted from the centrifuge medium and / or a precipitate in the centrifuge chamber.

[0002] To name a few examples that are not limiting of the present invention, the flow-through centrifuge may be a blood centrifuge, wherein the medium to be centrifuged is blood, and the modified medium or precipitate extracted is blood cells or blood particles; or a flow-through centrifuge, through which cells, microcarriers or other particles contained in the medium can be obtained from the medium. It is also possible that the medium after centrifugation is not a pure liquid, but a solution or suspension containing particles such as cells, cell fragments or cell microparticles.

[0003] For example, flow-through centrifuges can be used in biopharmaceutical companies for the production of biopharmaceutical products or in bioprocessing applications. For example, flow-through centrifuges can be used to obtain and / or clarify cells or microcarriers, and the cells obtained in this way can also be used in cell therapy. Another application area of ​​flow-through centrifuges is the production of vaccines, etc.

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

[0005] For example, Sartorius AG (address: Otto-Brenner-Str. 20, 37079 Göttingen, Germany) and related companies sell flow-through centrifuges of the same type under the trademark "Ksep" (registered trademark). On the website www.sartorius.com / en / products / process-filtrati0N / cell-harvesting / ksep-systems related to these flow-through centrifuges (check date: July 6, 2022), the functional principle of the flow-through centrifuge (which can also be used in the present invention) is described as follows according to the linked video:

[0006] The rotor of the flow-through centrifuge has any number (e.g., two or four) of centrifugal chambers, which can be designed to hold blood bags on the rotor body and are evenly distributed on the circumference. The centrifugal chambers are at equal radial distances from the axis of rotation of the rotor. The first connecting line leads to the centrifugal chamber in the radially inner part, while the second connecting line leads to the centrifugal chamber in the radially outer part. In the first operating phase, the first medium (e.g., blood) is supplied to the centrifugal chamber through the second connecting line, while the centrifugal chamber rotates with the rotor. In the centrifugal chamber, particles (e.g., blood cells) contained in the blood are deposited radially outside due to centrifugal action, while the residual medium (i.e., the medium supplied radially outside with reduced particles squeezed radially outward) is discharged from the centrifugal chamber in the radially inner part through the first connecting line. Therefore, in the first operating phase, the first connecting line is the discharge line, while the second connecting line is the supply line. As the operation continues, the proportion of particles in the centrifugal chamber and their concentration increase continuously until the centrifugal chamber is mostly and eventually completely filled with particles. In the subsequent optional second operating phase, the particles in the centrifugal chamber are washed. For this purpose, the washing or buffer solution enters the centrifugal chamber through the second connecting pipe. The washing or buffer solution rinses the centrifugal chamber and is discharged radially inwardly through the first connecting pipe. In this operating phase, the centrifugal chamber also rotates with the rotor to prevent the particles from flowing out of the centrifugal chamber through the first connecting pipe together with the washing or buffer solution under the action of centrifugal force. During the second operating phase, the first connecting pipe also serves as a discharge pipe for the washing or buffer solution, while the first connecting pipe serves as a supply pipe for the washing or buffer solution. In the subsequent third operating phase, the centrifugal chamber continues to twist with the rotor. In the third operating phase, the flow direction through the centrifugal chamber is opposite, the particles are removed from the centrifugal chamber through the second connecting pipe, and the washing or buffer solution can be replenished into the centrifugal chamber through the first connecting pipe. When all particles have been removed from the centrifugal chamber, the third operating phase ends. Subsequently, the above three operating phases can be circulated continuously.

[0007] EP3936601A1 describes the design of a media network that is connected to connecting pipes and ensures different operating phases. With regard to the media network, the pump device, process control unit, additional filter device, receiving containers for different media, and process flow contained therein, reference may also be made to EP3936601A1, EP2310486B1, and EP2485846B1.

[0008] EP2485846B1 points out that in a flow-through centrifuge, there may be problems with fluid connection with a connecting pipeline that rotates with the rotor through a rotating guide device, because the rotating guide device is prone to leakage and brings the risk of accidental contamination of the medium. On the other hand, according to US4,216,770, US4,419,089, US4,389,206 and US5,665,048, a connecting line is used, and the connecting pipeline can be integrated into the connecting line. One end area of ​​the connecting line is fixed to the housing, and the other end area is connected to the rotor and twisted with the rotor. In order to prevent the torsion of the rotor and the relative torsion of the end of the connecting line from causing the twisting of the connecting line to intensify, the connecting line is also additionally guided in a rotor compensation guide device in the form of a guide tube. The guide tube has a partial segment, which is in the shape of a rounded U-shaped, and its side feet are of different lengths and slightly separated. The opening of the U-shaped points in the direction of the rotor rotation axis. Starting from the end area fixed to the housing, the connecting line bends outward and enters the side legs of the U-shaped. In a partial section of the U, the connection line is guided around the rotor by a guide tube. The free end region of the other leg of the U of the guide tube is bent back so that it is coaxial with the axis of rotation of the rotor and directly adjacent to the point where the connection line enters the rotor. The guide tube is then driven at half the speed of the rotor. EP2485846B1 refers to US3,586,413 and explains how to avoid increasing the twisting of the connection line by using a rotating guide tube.

[0009] For more prior art, please refer to EP1295642A1. Summary of the invention

[0010] The object of the present invention is to provide a flow-through centrifuge and a compensating rotor guide for a flow-through centrifuge which are improved with regard to stress and fatigue resistance.

[0011] According to the invention, this object is achieved by the features of the independent claim. Further preferred embodiments of the invention can be derived from the dependent claims.

[0012] The invention relates to a flow-through centrifuge. The flow-through centrifuge has a rotor having (at least) one centrifuge chamber. The medium to be centrifuged can be arranged in the centrifuge chamber directly or in a suitable container and can be rinsed with other media (such as washing or buffer solutions). In the flow-through centrifuge, the rotor is twisted around the rotor axis at a certain rotor speed. The flow-through centrifuge has a connecting line. The connecting line has a connecting pipeline, through which the medium can be supplied to the centrifuge chamber (especially to a container arranged in the centrifuge chamber) when the flow-through centrifuge is operated with the rotor rotating. In addition, the connecting line also has a connecting pipeline, through which the medium can be discharged from the centrifuge chamber (especially the container arranged in the centrifuge chamber). Depending on the current operating phase, the flow direction through the connecting pipeline can be reversed. One end region of the connecting line is fixedly arranged on the housing, while the other end region of the connecting line twists with the rotor. In order to avoid the connection line twisting, the connecting line twists with the compensating rotor, wherein the connecting line is guided in a compensating rotor guide device (especially a guide pipe) of the compensating rotor. The compensating rotor and the compensating rotor guide are twisted around the rotor axis at half the rotor speed. In this respect, the design of the flow-through centrifuge can be identical with the flow-through centrifuge in the prior art mentioned at the beginning.

[0013] In conventional flow-through centrifuges, the connecting line consists of a flexible tube or hose (preferably a corrugated tube) through which the connecting line passes. The costs of such a connecting line are likely to be between 5,000 and 15,000 Euros, which include the connecting line and the interface to the rotor on the one hand and the interface to the medium network on the other hand. Since the connecting line is subject to great stress during operation of the flow-through centrifuge, it may only take 5 to 20 hours of operation before the connecting line needs to be replaced, which on the one hand leads to excessive replacement times and downtimes of the flow-through centrifuge and on the other hand also results in considerable costs. Since it is generally not possible to extend the service life of the connecting line by reducing the rotor speed or increasing the size of the connecting line and / or selecting a high-strength material for the connecting line, such a short service life of the connecting line must be tolerated according to the prior art.

[0014] The invention is based firstly on a study of the stresses acting on the connecting lines during operation of a flow-through centrifuge. The study on which the invention is based has led to the conclusion that in a flow-through centrifuge the connecting lines are subject to complex stresses:

[0015] a) The connecting line performs a relative rotational movement about the longitudinal axis in the compensating rotor guide. This relative rotational movement leads to friction between the connecting line and the compensating rotor guide. This friction leads to torsional stresses in the connecting line that vary with the longitudinal extension of the connecting line. In addition, the friction between the connecting line and the inner wall of the compensating rotor guide leads to the introduction of heat into the connecting line in the region of the contact and friction surfaces and, under certain circumstances, to wear.

[0016] b) The connecting line is guided in the compensating rotor guide device in such a way that it bends outwards following a first guide contour section of the compensating rotor guide device from an end region fixed to the housing and arranged coaxially with respect to the rotor axis. Starting from a point of inflection, the connecting line bends in the opposite direction in a second guide contour section of the compensating rotor guide device until the connecting line is guided radially outwardly through the rotor in a section oriented parallel to the rotor axis. Thus, in the above-mentioned guide contour section, the connecting line is guided according to an elongated S-shape, wherein the two ends of the S-shape are oriented parallel to each other, one end is coaxial with the rotor axis, and the other end has the maximum distance between the connecting line and the rotor axis. The connecting line is bent in the compensating rotor guide device according to the guide contour of the above-mentioned guide contour section and is therefore subjected to bending starting from its elongated initial position.

[0017] Due to the mechanical boundary conditions of the connecting line, i.e.

[0018] - one end region of the connecting line is fixed to the stationary housing,

[0019] the other end region of the connecting line is fastened to a rotor rotating at the rotor speed, and

[0020] - Guiding of the connecting line in a compensating rotor guide which rotates at half the rotor speed,

[0021] The bending of the connection line is not static, but a circumferential bending. Far away from the (imaginary) neutral fiber, the temporary radially outer material area of ​​the connection line, in particular the flexible hose or flexible (corrugated) pipe, is subjected to alternating stresses, i.e. alternating tensile stresses and alternating compressive stresses, due to the circumferential bending.

[0022] c) If the connection line has a bellows, circumferential bending of the bellows can cause the bellows or ribs to contact each other radially inside the bending guide contour, which can lead to nonlinearity of the bellows stiffness and thus to changes in the stress mechanism of the bellows.

[0023] d) The considerations on which the invention is based lead to the conclusion that the centrifugal forces acting on the longitudinal sections of the connecting line (in particular the hose or (corrugated) tube and the pipeline arranged therein and the medium arranged therein) are of a magnitude which depends on the distance of the respective longitudinal section from the rotor axis. In this case, the centrifugal forces acting on the respective longitudinal sections have

[0024] a first component, which acts in the direction of the guide surface of the compensating rotor guide, thereby increasing the contact pressure and friction between the connecting line and the compensating rotor guide; and

[0025] A second component which is oriented in the longitudinal direction of the connecting line and results in a tensile or compressive force in the longitudinal direction of the connecting line.

[0026] The division of the centrifugal force into two components is the result of a trigonometric function of the angle at which the longitudinal segment is inclined relative to the rotor axis.

[0027] In the first guiding profile section, the second component causes a tensile force which causes the connecting line to stretch, whereas in the second guiding profile section, the second component causes a compressive force which causes the connecting line to compress.

[0028] In this case, the tensile forces caused by the centrifugal force in the first material region of the connecting line at a first longitudinal extension coordinate of the connecting line (shorter distance from the rotor axis) are in particular greater than the tensile forces caused by the centrifugal force in the second material region of the connecting line at a second longitudinal extension coordinate of the connecting line (greater distance from the rotor axis). This is because, at the first longitudinal extension coordinate of the connecting line, a longer section of the connecting line is arranged radially outside the first material region of the connecting line, which can lead to greater tensile forces caused by the centrifugal force.

[0029] e) Depending on the applied stresses, the boundary conditions in the connection line may change. For example, an elongation of the connection line in a hose or (corrugated) tube may result in the connection line no longer being in close contact with the inner surface of the hose or (corrugated) tube, so that the hose or (corrugated) tube is no longer internally supported and the internal friction of the connection line changes. It is also possible that the longitudinal strength and / or the bending strength of the connection line changes as a result.

[0030] f) Any elasticity of the medium in the lines of the connecting line has a further significance, since the centrifugal forces caused by the elasticity can lead to pressure changes inside the connecting line, and to changes in the mass distribution and / or changes in the stiffness associated therewith.

[0031] Based on the above considerations, the above studies on the stresses in the connection lines and the experiments on which the invention is based, the invention proposes to use a compensating rotor guide device in a flow-through centrifuge, which compensating rotor guide device has a guide profile whose radius of curvature at a first distance from the rotor axis is greater than at a second distance from the rotor axis, wherein the first distance is smaller than the second distance.

[0032] This can be explained by a simplified example which does not limit the invention, namely that the guide profile is designed in the form of an S-shape elongated in the horizontal direction, whose lower left end region is oriented coaxially with the rotor axis and whose upper right end region is oriented parallel to the rotor axis. In the center between these two end regions there is a turning point, in the region of which the curvature changes its sign in a mathematical sense. For this simplified example, in a first guide profile segment between the lower left end region and the turning point, the radius of curvature constantly corresponds to the first radius of curvature, while in a second guide profile segment between the turning point and the upper right end region, the radius of curvature constantly corresponds to the second radius of curvature, wherein the second radius of curvature is smaller than the first radius of curvature.

[0033] In the first guide profile segment, due to the circumferential bending, the cross section is subjected to a circumferential bending stress at the respective longitudinal extension coordinates, the magnitude of which can be constant within the longitudinal extension range, but its sign changes with the harmonic trend of the circumferential bending. The circumferential bending stress is superimposed by a tensile stress, which comes from the mass of the connecting line, is generated by the centrifugal force corresponding to the distance from the rotor axis and is quadratically related to the rotation speed. At the first end of the first guide profile segment, i.e., the position where the bending starts from the coaxial axis with the rotor axis, a centrifugal force acts, which is generated by the entire section of the connecting line in the first guide profile segment and may also be generated by a section in the second guide profile segment. For the longitudinal extension coordinates of the first guide profile segment that are farther away from the rotor axis, the tensile force acting on the longitudinal extension coordinate due to the centrifugal force in the cross section is reduced, so that at the first end, the tensile force caused by the centrifugal force and the tensile stress caused by the centrifugal force are the largest. Then, the circumferential bending stress and the tensile stress caused by the centrifugal force are superimposed on the cross section at the respective longitudinal extension coordinates. If circumferential bending temporarily results in circumferential bending compressive stresses, the superposition of the tensile stresses caused by the centrifugal force leads to a reduction in the stresses generated, which is beneficial for the material stresses. However, shortly afterwards, the same cross-sectional area is also subjected to circumferential bending tensile stresses during further circumferential bending, and the superposition of the tensile stresses caused by the centrifugal force leads to the addition of the circumferential bending tensile stresses and the tensile stresses caused by the centrifugal force. This leads to an increase in the maximum stresses generated, which is also a possible reason for limiting the service life of the connecting line.

[0034] The design of the present invention can reduce the maximum stress generated, thereby extending the service life (probably significantly):

[0035] According to the invention, the radius of curvature is selected to be larger at or near the rotor axis. By increasing the radius of curvature, the amplitude of the circumferential bending stress can be reduced, thereby reducing the maximum stress generated and thus reducing the stress, although as mentioned above, the stress is superimposed on the tensile stress caused by the centrifugal force.

[0036] According to the present invention, the guide profile has a first guide profile segment and a second guide profile segment. For the above example, each guide profile segment can be designed as a quarter circle, and their curvature directions are opposite, wherein in this case, the guide profile segments have different radii. However, it is also possible to have guide profile segments with different curvature radii in at least one guide profile segment, wherein the curvature radius can change in a step-like manner, or it can also change continuously. For the suggestion of the present invention, the guide profile segment has a curvature in a first direction, and the second guide profile segment has a curvature in a second direction. The first guide profile segment and the second guide profile segment are connected to each other through an intermediate segment, which is preferably oriented radially relative to the rotor axis. For the example of the quarter circle guide profile segment introduced at the beginning, the intermediate segment can be formed by the local connection points of the ends of the guide profile segment facing each other, wherein a straight line, preferably radially oriented intermediate segment can also be extended between these ends. Alternatively or cumulatively, the first guide profile segment and the second guide profile segment can also be connected to each other through a turning segment, and the curvature sign changes in the turning segment. The distance between the first guide profile segment and the rotor axis is smaller than that of the second guide profile segment. The radius of curvature in the first guide profile segment is greater than the radius of curvature in the second guide profile segment. To name a few examples that do not limit the invention, the radius of curvature in the first guide profile segment may 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% greater than the radius of curvature in the second guide profile segment. For example, this may:

[0037] - discrete radii of curvature that apply only at certain longitudinal extension coordinates of the guiding profile segment,

[0038] - for partial segments of guide contour segments with a constant radius of curvature,

[0039] - applies to the mean radius of curvature in the guiding contour segment, or

[0040] - Applies to all curvature radii that change continuously in the guiding contour segment.

[0041] Alternatively or additionally, the radius of curvature in the first guide contour section can also decrease continuously or in steps along the longitudinal extension direction and with increasing distance from the rotor axis.

[0042] In principle, within the scope of the invention, the connecting line can be constructed in any manner. Preferably, the connecting line has a bellows through which the different lines of the connecting line, in particular the connecting line, can extend. The bellows has the functions of bundling the lines, protecting the lines, guiding and encapsulating the lines.

[0043] In a special proposal of the present invention, the radius of curvature in the first guide profile segment decreases continuously with increasing distance from the rotor axis. This may only apply to the first guide profile segment. Preferably, the radius of curvature in the second guide profile segment also decreases continuously with increasing distance from the rotor axis.

[0044] As mentioned above, the stresses in the connecting lines in the guide are quite complex, which also complicates the geometrical design requirements of the flow-guiding contour segments. In one embodiment of the flow-through centrifuge, the radius of curvature of the first guide contour segment and / or the second guide contour segment at different longitudinal extension coordinates is dimensioned such that at these or all longitudinal extension coordinates, the stresses in the connecting lines guided in the compensating rotor guide are constant or vary by a maximum of ±20%, a maximum of ±15%, a maximum of ±10% or a maximum of ±5%. The stress that is to remain constant or vary only by a specified percentage is determined by the superposition of two different partial stresses:

[0045] - tensile stresses in the connecting line at the longitudinal extension coordinate, which are caused by centrifugal forces caused by connecting line sections arranged radially outside the longitudinal extension coordinate;

[0046] - circumferential bending stresses of the connecting line at the coordinates of the longitudinal extension, which are caused by a circumferential bending of the connecting line corresponding to said bending of the connecting line.

[0047] This design is based on the assumption that the two aforementioned partial stresses are decisive for the strength of the connection line, wherein on the one hand safety can be taken into account by means of a specified percentage change range and on the other hand other occurring stresses (friction, heating, wear, etc.) can be taken into account.

[0048] For alternative or cumulative design criteria, the radius of curvature is dimensioned such that the two stress components in the longitudinal extension of the connection in the first guide profile segment and / or the second guide profile segment are at least a predetermined percentage less than the permissible stress of the connection. For example, the manufacturer may specify a maximum static bending stress when a bellows is used in the connection, so that in this case the stress determined from the two stress components is a predetermined percentage less than the bending stress specified by the manufacturer. The other permissible stress corresponding to the stress determined from the stress components may be a maximum dynamic tensile stress and / or bending stress, or a predetermined tensile strength or fatigue strength of the connection or a component of the entire connection.

[0049] As mentioned above, another solution to the task of the present invention is a compensating rotor guide device for a flow-through centrifuge. The compensating rotor guide device has a guide tube or is composed of a guide tube, wherein the guide tube has a guide profile, and the guide profile has a first guide profile segment and a second guide profile segment. The first guide profile segment has a curvature in a first direction, and the second guide profile segment has a curvature in a second direction opposite to the first direction. The first guide profile segment and the second guide profile segment are connected to each other through an intermediate segment preferably oriented radially relative to the rotor axis or through a turning segment. The distance between the first guide profile segment and the rotor axis is smaller than that of the second guide profile segment. The radius of curvature in the first guide profile segment is larger than the radius of curvature in the second guide profile segment. In the guide tube, the radius of curvature in the first guide profile segment may become smaller in the direction of the end region facing the second guide profile segment, which can be performed in a step-like manner or can also be performed continuously.

[0050] Further advantageous developments of the invention are apparent from the claims, the description and the drawings.

[0051] The advantages of the features and combinations of several features mentioned in the specification are merely exemplary and may be effective alternatively or cumulatively, but these advantages do not necessarily have to be achieved by the embodiments according to the present invention.

[0052] With regard to the disclosure of the original application documents and the patent (but not the scope of protection), the following applies: Further features can be taken from the drawings - in particular the geometric shapes shown in the drawings and the relative dimensions between the several components as well as their relative arrangement and functional connection. Combinations of features from different embodiments of the invention or features from different claims are also possible, which may deviate from the reference relationships selected in the claims and are hereby disclosed. This also applies to features shown in separate drawings or mentioned in their description. These features can also be combined with features from different claims. Similarly, in further embodiments of the invention, the features listed in the claims can also be omitted, but this does not apply to authorized independent claims.

[0053] The features mentioned in the claims and the description are to be understood in terms of their quantity to mean exactly that number or more than the number mentioned, without the explicit use of the adverb "at least". Thus, for example, when one element is mentioned, it is to be understood that there is exactly one element, two elements or more. The features listed in the claims may be supplemented by other features or may be the only features possessed by the subject matter of the respective claim.

[0054] The reference numerals in the claims do not limit the scope of the objects protected by the claims. They are only used to make the claims easier to understand. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present invention will be further explained and illustrated below with reference to the preferred embodiments shown in the drawings.

[0056] Figure 1 A flow-through centrifuge with connecting lines (guiding devices not shown) is shown highly schematically in a spatial half longitudinal section.

[0057] Figure 2 Shown can be used Figure 1 The connecting lines in the guide device of the flow-through centrifuge are shown.

[0058] Figures 3 to 5 Table showing dimensions of the guide tube curvature radius of a compensating rotor guide.

[0059] Figure 6 Example curves showing the radius of curvature of the guide tube of a compensating rotor guide, and the tensile force due to centrifugal force as a function of the distance from the rotor axis.

[0060] Figure 7 A schematic diagram shows auxiliary considerations for determining the tensile forces acting on the pipes or hoses of the connecting lines due to the centrifugal force in the longitudinal section at the longitudinal extension coordinate and at the distance from the rotor axis. DETAILED DESCRIPTION

[0061] In the figures, corresponding or similar components or features are partly marked with the same reference numerals, wherein these components or features can be distinguished from one another by additional letters a, b, ... In this case, these components or features can be referenced with or without additional letters, thereby referring to one, several or all components or features.

[0062] Figure 1 A semi-longitudinal section through a flow-through centrifuge 1 is shown in a highly schematic perspective view. The flow-through centrifuge 1 has a housing 2 and, in particular, a vessel 3 with a wall 4. The wall 4 of the vessel 3 delimits a rotor chamber 5 in which a rotor 6 rotates about a rotor axis 7 at a rotor speed. Figure 1 In the schematic diagram of FIG. 1 , only containers 8 a, 8 b (here two containers 8 a, 8 b, but any other number of containers 8 may be present) arranged in the centrifugal chamber of the rotor 6 are shown for the rotor 6, which may be, for example, blood bags 9 or any other containers. Here, these containers 8 are evenly distributed around the rotor axis 7 in the circumferential direction and are at the same distance from the rotor axis 7.

[0063] The flow-through centrifuge 1 has a rotor chamber temperature control circuit 10. Figure 1 Only one of the rotor chamber temperature control rings 11 is shown in the figure. The rotor chamber temperature control ring 11 is integrated into the wall 4 of the vessel 3 and is wound around the rotor axis 7 and the rotor chamber 5 several times.

[0064] In addition, Figure 1 1 . The connecting line 12 can be seen in the figure. The connecting line 12 has a flexible hose or flexible tube 13, in particular a bellows. A temperature control supply line 14 and a temperature control discharge line 15 can be used to control and cool the connecting line and extend selectively through the hose or tube 13. Two connecting lines 16, 17 extend through the hose or tube 13, through which the medium flows in different directions in different operating phases of the centrifugation process. In one end region 18, the connecting line 12 is fixed to the housing 2 or to the wall 4 of the kettle 3, while in the other end region 19, the connecting line 12 is fixed to the rotor 6 and rotates with it.

[0065] A compensating rotor also rotates about the rotor axis 7, wherein the speed of the compensating rotor is half the speed of the rotor 6. The compensating rotor has a compensating rotor guide device 20, which is arranged at Figure 2 2 and is designed as a guide tube 21. The guide tube 21 has two guide tube halves 22, 23, which are separated from each other by a dividing line 24 indicated by a dashed line. The guide tube 21 has a constant circular cross section along a longitudinal extension coordinate 25, wherein the longitudinal extension coordinate 25 is curved in different directions, which will be explained in detail below. The connecting line 12 is designed as a bellows, which extends through the guide tube 21. At the two end regions of the guide tube 21, the connecting line 12 extends out of the guide tube 21 so that it can be fixed to the housing 2 or the rotor 6. There is a radial gap between the inner surface 26 of the guide tube 21 and the circumference of the connecting line 12, wherein, depending on the curvature of the connecting line 12 and the connecting line stresses described above, the connecting line 12 may contact the inner surface 26 of the guide tube 21 on one side.

[0066] In the guide tube half 22, the guide tube 21 has a guide profile 27 formed by an inner surface 26. The guide profile 27 has a first guide profile section 28 and a second guide profile section 29, which are directly connected by a deflection section 30. In the present exemplary embodiment, the deflection section 30 simultaneously forms a middle section 31, in the region of which the guide tube 21 is oriented radially relative to the rotor axis 7. In the first guide profile section 28, the guide profile 27, in particular the longitudinal extension coordinate 25 of the guide tube 21, has a first radius of curvature 32, while in the second guide profile section 29, the guide profile 27 has a second radius of curvature 33. Figure 2In the embodiment of the invention, 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, wherein the second radius of curvature 33 is 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, while in the deflection section 30 it is the opposite, so that in the second guide profile section 29, the curvature of the longitudinal extension coordinate 25 is clockwise. The guide profile sections 28, 29 each extend at a circumferential angle of 90°. However, a smaller circumferential angle can also be used, so that in this case the guide tube 21 is oriented non-radially relative to the rotor axis 7 in the deflection section 30.

[0067] like Figure 2 As shown, an end region 34 of the first guide profile segment 28 is oriented (approximately) coaxially with respect to the rotor axis 7, while the other end region 35 of the first guide profile segment 28 is oriented radially with respect to the rotor axis 7. The end region 36 of the second guide profile segment 29 is flush with the end region 35 in the deflection section 30 and the middle section 31, and this 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 segment 29 is oriented parallel to the rotor axis 7, wherein the distance of the guide tube 21 from the rotor axis 7 is greatest in this region. In principle, the second guide tube half 23 can be designed to be mirror-symmetrical with respect to the dividing line 24 of the first guide tube half 22. For the illustrated embodiment, this mirror symmetry only applies to the second guide profile segment 29', while the first guide profile segment 28' in the second guide tube half 23 is not mirror-connected to the second guide profile half 29', so that in the direction of the longitudinal extension coordinate 25, the two guide profile segments 28', 29' are both bent in the clockwise direction and together form a semi-ring with a curvature radius of 32', which increases in the direction of the longitudinal extension coordinate 25 in the area of ​​the turning section 30' and the intermediate section 31'.

[0068] Therefore, for Figure 2 In the embodiment shown, the guide tube 21 can be composed of two guide profile parts assembled together and forming the guide profile segments 29, 29' and two guide profile parts forming the guide profile segments 28, 28', so that in some cases, the same parts can be used to manufacture the guide tube 21. However, it is also understood that, depending on the manufacturing process used, the guide tube 21 can also be manufactured in a single piece.

[0069] Figure 2 The guide profile segments 28 , 29 shown are merely examples and do not restrict the invention.

[0070] For a suggestion, Figure 2In contrast, the radius of curvature 32 in the guide contour section 28 is not constant. Instead, it decreases along the longitudinal extension coordinate 25 in a stepped or stepless manner.

[0071] It is also possible that the radius of curvature 32 initially decreases continuously (for example only in the vicinity of the end 34 ) and then remains constant or continues to decrease in steps in the guide contour section 28 .

[0072] For all exemplary embodiments, a constant radius of curvature 33 , a radius of curvature 33 which decreases in steps, or a radius of curvature 33 which decreases continuously in one section and is constant or changes in steps in another section can be used in the second guide contour segment 29 .

[0073] In the following, an exemplary possibility for determining the curvature radii 32, 33 of the guide tube 21 of the compensating rotor guide 20 will be explained, wherein a simplified calculation with simplified assumptions is explained here, and it is not intended that the invention is limited to determining the curvature radii in this way. In the following exemplary calculation, it is assumed that the hose or (corrugated) tube 13 follows the course of the guide contour 27 of the guide tube 21. From Figure 2 It can be seen that the actual situation is not the case. Therefore, in order to improve the calculation accuracy, the direction of the hose or (corrugated) tube 13 in the guide tube 21 must be determined, and then the curvature radius of the direction must be calculated accordingly.

[0074] In this example calculation, a hose or (corrugated) tube 13 with a diameter D of 0.013 m is used as the basis. When subjected to a longitudinal tensile force, its spring constant is c=5000 [tensile force (Newton / strain)]. This spring constant c can be given by the manufacturer or can also be determined by a simple tensile test.

[0075] exist Figure 3 The table shows that in the range of 0N to 330N, the hose or (corrugated) tube 13 is subjected to different tensile forces F Zug When the hose or (bellows) tube 13 is acted upon, the strain D resulting from the spring constant c Zugkraft for:

[0076] D Zugkraft =F Zug / C (see first and second columns).

[0077] If a hose or tube is bent with a radius of curvature R, the material area outside the bend is stretched, while the material area inside is compressed. The strain D in the radially outer area due to the bend Biegung It can be determined by the following formula:

[0078] D Biegung =0.5D / (R+0.5D).

[0079] exist Figure 3 The fourth row of the table shows the strain D caused by this bending within the range of curvature radius R of 0.45 m to 0.175 m given in the second row. Biegung .

[0080] If during operation, the bending strain D Biegung and tensile strain D Zugkraft Superimposed on the area of ​​the material that is stretched to the maximum due to bending, the tensile strain D Zugkraft and pure bending strain D Biegung join in Figure 3 The table shows the strain D resultierend .

[0081] If the radius of curvature R is designed so that the superimposed strain D resultierend If it is always less than 12%, then only Figure 3 The strain D caused by the curvature radius R highlighted in bold in the table resultierend It follows that for strains D less than 12% resultierend :

[0082] - For a tensile force of 0 N to 60 N (i.e. when the longitudinal extension coordinate 25 is away from the rotor axis 7, the direction of the guide tube 21 is preferably parallel to the rotor axis 7, so there is no centrifugal force), the radius of curvature R can be 0.055 m;

[0083] - For a tensile force of 90N to 120N, the radius of curvature R may be 0.065m;

[0084] - For a tensile force of 150N to 180N, the radius of curvature R may be 0.075m;

[0085] - For a tensile force of 210N to 240N, the radius of curvature R may be 0.085m,

[0086] -For a tensile force of 270N, the radius of curvature R can be 0.095m,

[0087] -For a tensile force of 300N, the radius of curvature R can be 0.105m,

[0088] For a tensile force of 330 N, which results, for example, at the longitudinal extension coordinate 25 of the guide tube 21 in the guide profile section 8 in the end region 34 , the radius of curvature R can be 0.115 m.

[0089] (It is also possible to use smaller step tensile forces or continuously changing tensile forces for corresponding calculations).

[0090] exist Figure 4In the table shown, the first column specifies the length of the guide tube 21 from the rotor axis 7 along the longitudinal extension coordinate 25, ranging from 0 m to 0.21 m, which corresponds to the length up to the separation line 24. The second column specifies the angle 43 of the longitudinal section of the connecting line 12 arranged at the longitudinal extension coordinate 25 relative to the orientation radial to the rotor axis 7, expressed in radians. At the longitudinal extension coordinate 0.00 m, i.e. upon entry into the guide tube 21, the angle 43 is π / 2, while at the turning section 30 the angle 43 is zero, and at the end region 37 the angle 43 is -π / 2.

[0091] If it is simplified to assume that the two guide contour sections 28 , 29 are curved in a quarter circle with the same radius of curvature R, the angle 43 between these characteristic angles 43 at the respective longitudinal extension coordinate 25 can be calculated as follows:

[0092] Angle 43 = π / 2-(π / 2×longitudinal extension coordinate 25 / R),

[0093] Here, the radius of curvature R is assumed to be 0.105 meters.

[0094] The distance A of the longitudinal segment at the longitudinal extension coordinate 25 can be derived as follows:

[0095] A = R (1-sin (angle 43)),

[0096] The distance A is Figure 4 is shown in the third column.

[0097] If, for example, it is assumed that the relative mass per length of the connecting line 12 is m r = 0.3705 kg / m, then the relative centripetal acceleration at each longitudinal extension coordinate 25 (which is determined by the absolute centripetal acceleration a z and the gravitational acceleration g) can be calculated as follows:

[0098] a z / g=(2πn) 2 A / g,

[0099] Where n is the rotational speed of the compensation rotor guide device 20 and for this exemplary calculation is 36.67 rpm (2200 rpm), where g=9.813 m / s 2 .

[0100] If the relative centripetal acceleration a z / g multiplied by the relative mass m r and the longitudinal length ΔL (where ΔL = 0.01 m), we can derive Figure 4 Values ​​in column 5. Thus, in this column the centrifugal force acting on the longitudinal segment is shown as a function of the longitudinal segment length AL.

[0101] If you want to calculate Figure 4 The tensile force acting at the longitudinal extension coordinate 25 given in the last column of the table must be calculated as the centrifugal force acting at the longitudinal segment 25 (starting from the radially outermost longitudinal segment at the longitudinal extension coordinate 0.21 m). This centrifugal force is obtained by multiplying the corresponding value in the fifth column by g, and the result must be multiplied by Figure 4 The cosine of the angle 43 in the second column of the table in FIG. 4 is the cosine of the angle 43. This is because only the component calculated from the cosine of the angle 43 contributes to the tensile force acting in the direction of the longitudinal extension coordinate 25. When transitioning to the next radially inner adjacent longitudinal segment 25, the previously determined tensile force must be added to the tensile force calculated from the changed angle and the changed longitudinal extension coordinate 25 for this further longitudinal segment 25. In the last column, the tensile force components of increasingly radially outer longitudinal segments in the direction of the longitudinal extension coordinate 25 are added.

[0102] exist Figure 4 The tensile force at each longitudinal extension coordinate 25 determined in the last column is also recorded Figure 5 In the third column, calculate the strain D Zugkraft .according to Figure 3 , in the subsequent columns the bending strain D for different radii of curvature R is calculated Biegung and tensile force strain D Zugkraft The superimposed strain D resultierend .

[0103] If the design requires the resulting strain D resultierend Should be kept less than 12%, the radius of curvature R must be selected so that Figure 5 The strain shown in bold is D resultierend . This means:

[0104] - for a longitudinal extension coordinate 25 in the range of 0.0 m to 0.05 m, the radius of curvature R may be 0.115 m;

[0105] - for a longitudinal extension coordinate 25 in the range of 0.06 m to 0.09 m, the radius of curvature R may be 0.105 m;

[0106] - for a longitudinal extension coordinate 25 in the range of 0.10 m to 0.11 m, the radius of curvature R may be 0.095 m,

[0107] - for a longitudinal extension coordinate 25 in the range of 0.12 m to 0.14 m, the radius of curvature R may be 0.085 m,

[0108] - for a longitudinal extension coordinate 25 in the range of 0.15 m to 0.16 m, the radius of curvature R may be 0.075 m,

[0109] - for a longitudinal extension coordinate 25 in the range of 0.17 m to 0.18 m, the radius of curvature R may be 0.065 m, and

[0110] For a longitudinal extension coordinate 25 in the range of 0.19 m to 0.21 m, the radius of curvature R may be 0.55 m.

[0111] It is also possible to carry out a more refined subdivision or a continuous calculation of the longitudinal extension coordinate 25. Excessive strains can also be avoided if the radius of curvature of the respective longitudinal extension coordinate 25 is greater than the radius of curvature given in the above table.

[0112] exist Figure 6 In FIG. 1 , the coordinate 38 of the longitudinal extension coordinate 25 of the guide tube 21 or hose or (corrugated) tube 13 shows, on the one hand, the tensile forces 39 (see solid line, which is determined using the spline approximation of the determined tensile forces) caused by the centrifugal force. On the other hand, if the resulting strain D resultierend The maximum is 12%, and the radius of curvature R40 is shown here (see the dotted line, which is also determined using the spline approximation method).

[0113] As mentioned above, Figure 6 The calculation method and curve trends shown are only exemplary and make simplified and possibly distorted assumptions. As mentioned above, the actual radius of curvature R can be compared with the table or Figure 6 The radius of curvature R can be kept constant in the partial segments, in particular in the guide contour segment 28 on the one hand and in the guide contour segment 29 on the other hand, provided that the radius of curvature R is larger in the partial segment adjacent to the rotor axis 7 than in the partial segment remote from the rotor axis 7. It is also possible to use a segment-by-segment follow-up of the radius of curvature R. Figure 6 The curve, step or any other suitable trend in the embodiment.

[0114] Figure 7 A highly simplified schematic diagram (for example, ignoring the friction between the connection line 12 and the hose or tube 13 and the support of the hose or tube 13 radially outward) is shown for auxiliary consideration. In this case, the connection line 12 (especially the hose or tube 13 and / or the pipelines 14, 15, 16, 17) is divided into longitudinal segments 41 of equal size, which are distinguished by the suffixes "-1", "-2". These longitudinal segments 41 have the same mass Δm due to the same size, but their respective distances A1, A2, ... from the rotor axis 7 are different. Figure 7 The centrifugal acceleration is indicated by reference numeral 42 and is distinguished by suffixes "-1", "-2", ... z Acting on each longitudinal segment 41 , the following applies for the centrifugal acceleration:

[0115] az =(2πn) 2 A,

[0116] Wherein, A is the respective distance 42 between the longitudinal section 41 and the rotor axis 7, and n is the rotation speed of the compensation rotor guide device 20 (unit: [s -1 ]). Thus, the centrifugal force F acting on the longitudinal section 41 z It follows from the following:

[0117] F z =Δm a z .

[0118] For each longitudinal segment 41, the centrifugal force F z Only a force component which is dependent on the angle 43 of the respective longitudinal extension results in a tensile force acting in the direction of the longitudinal extension.

[0119] For the first longitudinal section 41 - 1 arranged coaxially with the rotor axis 7 , in the simplified view chosen here, the tensile force F acting on the longitudinal section 41 - 1 is Zug,1 It is obtained from the sum of the centrifugal forces that the longitudinal section 41-1 must withstand, that is, from the sum of the force components of the centrifugal force acting in the direction of the longitudinal extension coordinate 25, which act on the longitudinal sections 41-2, 41-3, .... Therefore, for the tensile force F acting on the longitudinal section 41-1 Zug,1 The following applies:

[0120] F Zug,1 =Δm 4π 2 n 2 (C2A2+C3A3+C4A4+......),

[0121] For the next longitudinal section 41 - 2 , the tensile force F can be determined accordingly as follows: Zug,2 :

[0122] F Zug,2 =Δm 4π 2 n 2 (C3A3+C4A4+......).

[0123] And so on.

[0124] On the one hand, C represents 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. In addition, other correction factors can also be taken into account in C, such as friction. The above simplified observation shows that the tensile force F Zug The tensile force and stress are the largest at the longitudinal section 41 - 1 , and decrease as the distance between the longitudinal section 41 and the rotor axis 7 increases.

[0125] In certain cases, the acting stresses can be modeled more accurately, wherein the qualitative statement that the fatigue resistance can be increased by increasing the radius of curvature of the longitudinal section 41 near the rotor axis 7 remains unchanged.

[0126] List of reference numerals:

[0127] 1Flow-through centrifuge

[0128] 2 Shell

[0129] 3 cauldron

[0130] 4 walls

[0131] 5 Rotor chamber

[0132] 6 rotors

[0133] 7 Rotor axis

[0134] 8 containers

[0135] 9 Blood Bags

[0136] 10 Rotor chamber temperature control circuit

[0137] 11 Rotor chamber temperature regulating ring

[0138] 12 Connection lines

[0139] 13Hose, tube

[0140] 14 Temperature control supply line

[0141] 15 Temperature control discharge pipe

[0142] 16 Connecting pipes

[0143] 17 Connecting pipes

[0144] 18 End area

[0145] 19 End area

[0146] 20 Compensating rotor guide device

[0147] 21 Guide tube

[0148] 22 Guide tube half

[0149] 23 Guide tube half

[0150] 24 Divider

[0151] 25 Vertical extension coordinate

[0152] 26 Inner surface

[0153] 27 Guide profile

[0154] 28 First guiding contour segment

[0155] 29 Second guiding contour segment

[0156] 30 Turning section

[0157] 31 Middle section

[0158] 32 First radius of curvature

[0159] 33 Second radius of curvature

[0160] 34 End area

[0161] 35 End area

[0162] 36 End area

[0163] 37 End area

[0164] 38 Distance

[0165] 39 Tensile force

[0166] 40 Radius of curvature

[0167] 41 longitudinal segment

[0168] 42 Distance

[0169] 43 angles.

Claims

1. A flow-through centrifuge (1), comprising: a) a rotor (6) having a centrifugal chamber, wherein the rotor (6) is rotatable about a rotor axis (7) at a rotor speed; and b) a connecting line (12) comprising: a connecting line (16; 17) through which a medium can be supplied to the centrifuge chamber when the flow-through centrifuge (1) is operated with the rotor (6) rotating; and a connecting line (17; 16) through which a medium can be discharged from the centrifuge chamber, c) wherein one end region (18) of the connecting line (12) is fixedly arranged on the housing and the other end region (19) of the connecting line (12) rotates with the rotor (6), d) in order to prevent the connecting line (12) from twisting, the connecting line (12) is guided in a compensating rotor guide (20) which is twisted about the rotor axis (7) at half the rotor speed, e) wherein the compensating rotor guide (20) has a guide profile (27) whose radius of curvature (32) at a first distance from the rotor axis (7) is greater than the radius of curvature (33) at a second distance from the rotor axis (7), wherein the first distance is smaller than the second distance, f) the guide profile (27) has a first guide profile segment (28) and a second guide profile segment (29), g) the first guide profile segment (28) has a curvature in a first direction, and the second guide profile segment (29) has a curvature in a second direction, h) the first guide profile segment (28) and the second guide profile segment (29) are connected to each other via an intermediate segment (31) or a deflection segment (30) which is preferably oriented radially with respect to the rotor axis (7), i) the first guide profile segment (28) is at a smaller distance from the rotor axis (7) than the second guide profile segment (29), It is characterized in that j) The radius of curvature (32) in the first guide contour segment (28) is greater than the radius of curvature (33) in the second guide contour segment (29), wherein the radius of curvature (32) in the first guide contour segment (28) preferably decreases in the direction of the longitudinal extension coordinate (25) and with increasing distance from the rotor axis (7).

2. The flow-through centrifuge (1) according to claim 1, characterized in that The connecting line (12) has a bellows.

3. The flow-through centrifuge (1) according to one of the preceding claims, characterized in that The radius of curvature (32) in the first guide contour section (28) and / or the radius of curvature (33) in the second guide contour section (29) decreases continuously with increasing distance from the rotor axis (7).

4. The flow-through centrifuge according to claim 3, characterized in that In the first guide profile section (28) and / or the second guide profile section (29), the curvature radii (32; 33) at different or all longitudinal extension coordinates (25) are dimensioned such that at the longitudinal extension coordinate (25), the stresses in the connecting line (12) guided in the compensating rotor guide (20) are a) a tensile stress of the connecting line (12) at the respective longitudinal extension coordinate (25), which tensile stress is caused by centrifugal forces caused by the longitudinal section of the connecting line (12) arranged radially outside the respective longitudinal extension coordinate (25), and b) the circumferential bending stress of the connecting line (12) at the respective longitudinal extension coordinates (25), which circumferential bending stress is caused by the circumferential bending of the connecting line (12) corresponding to the curvature radius (32; 33), and is constant in the longitudinal extension or varies only by a maximum of ±20%, a maximum of ±15%, a maximum of ±10% or a maximum of ±5%.

5. The flow-through centrifuge (1) according to claim 3 or 4, characterized in that In the first guide profile section (28) and / or the second guide profile section (29), the curvature radii (32; 33) at different or all longitudinal extension coordinates (25) are dimensioned such that at the longitudinal extension coordinate (25), the stresses in the connecting line (12) guided in the compensating rotor guide (20) are a) a tensile stress of the connecting line (12) at the respective longitudinal extension coordinate (25), which tensile stress is caused by centrifugal forces caused by the longitudinal section of the connecting line (12) arranged radially outside the respective longitudinal extension coordinate (25), and b) at the respective longitudinal extension coordinates (25), the circumferential bending stress of the connecting line (12) - the circumferential bending stress resulting from the circumferential bending of the connecting line (12) corresponding to the curvature radius (32; 33) - is at least a predetermined percentage less than the permissible stress of the connecting line (12).

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

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