EP4656291A1

EP4656291A1 - Centrifuge for continuous flow centrifugation

Info

Publication number: EP4656291A1
Application number: EP24179344.7A
Authority: EP
Inventors: Michael Blocher; Henning JONAS; Rafael WEIPPERT; Thomas EBERHAGEN; Matthias Hielscher
Original assignee: Sartorius Stedim Biotech GmbH
Current assignee: Sartorius Stedim Biotech GmbH
Priority date: 2024-05-31
Filing date: 2024-05-31
Publication date: 2025-12-03
Also published as: WO2025248037A1

Abstract

The invention relates to a centrifuge for continuous flow centrifugation, wherein the centrifuge (1) comprises a drum (3), a rotor (4) and a motor (5) for driving the drum (3) and the rotor (4), wherein the centrifuge (1) comprises a drive bearing arrangement (7) with at least two drive roller bearings (8) with an inner race (9), an outer race (10) and a lubricant, wherein one of the drive roller bearings (8) comprises a sealing (11), wherein the drive roller bearings (8) rotate around the common rotation axis (A), wherein the drive bearing arrangement (7) comprises a bearing housing (12) with an outer wall (13). It is proposed that the outer wall (13) comprises a ridge (14) connected to the outer wall (13) by a connection providing a sealing (11) function and extending from the outer wall (13) towards the inner races (9) along the sealing (11).

Description

The present invention relates to a centrifuge for continuous flow centrifugation according to the general part of claim 1 and to a method of use of a centrifuge according to claim 15.
Centrifuges for continuous flow centrifugation and in particular centrifuges for fluidized bed centrifugation, which are of particular interest here, are used for a range of applications in biotechnology, including cell therapy, vaccine production and cell cultivation for recombinant protein production like antibody production. Generally, the type of continuous centrifuge in focus here comprises a rotor with chambers which are usually single-use chambers that can be fed with media while rotating. A force equilibrium between the centrifugal force and a fluid flow in the opposite direction suspends particles of different sizes at different locations in the chambers. Accordingly, applications of fluidized bed centrifuges comprise for example cell separation.
As the chambers can be filled and emptied while rotating, an anti-twisting mechanism is implemented for the tubes leading to the chambers. This anti-twisting mechanism is based on the known principle that the chambers may rotate with double the velocity of the tubes without the tubes twisting. Implementing this principle puts a number of constructional restraints on the centrifuge, leading to complex mechanics.
The known prior art ( EP 4 321 255 A1 ) that builds the basis of the invention is related to a centrifuge according to the general part of claim 1. This document also summarizes the general working principle of fluidized bed centrifuges. This document shows a centrifuge for continuous flow centrifugation, wherein the centrifuge comprises a drum, a rotor and a motor for driving the drum and the rotor, wherein the drum, driven by the motor, rotates around a common rotation axis with a rotational frequency during use of the centrifuge, wherein the rotor is coupled to the drum, wherein due to being coupled to the drum, the rotor, driven by the motor, rotates around the common rotation axis with the double of the rotational frequency, wherein the centrifuge comprises a drive bearing arrangement, wherein the drive bearing arrangement comprises at least two drive roller bearings, wherein the drive roller bearings each comprise an inner race, an outer race and a bearing axis, wherein one of said races is connected to the drum and one of said races is connected to the rotor, wherein the drive roller bearings each comprise a lubricant, wherein at least one of the drive roller bearings comprises a sealing separate from and connected to the outer race and extending towards the inner race, wherein the bearing axes of the drive roller bearings are each located spaced apart from, and in particular parallel to, the common rotation axis, such that the drive roller bearings rotate around the common rotation axis, wherein the drive bearing arrangement comprises a bearing housing, wherein the bearing housing comprises an outer wall rotationally fixed to the outer races of the drive roller bearings. The roller bearings there are ball bearings. A known way of keeping the lubricant of ball bearings inside is the use of sealed bearings as described in EP 4 321 255 A1 .
Another way of keeping ball bearings lubricated is encasing the ball bearings in a chamber and lubricating the chamber, as for example shown in US 2015/0174539 A1 . In both documents the ball bearings are located on a rotating drum such that the ball bearings as a whole are subject to centrifugal forces. In US 2015/0174539 A1 the ball bearings are oriented at an angle to the centrifugal force and the chamber in which the ball bearings are placed is closed at a side in the direction of centrifugal force from the ball bearings, such that lubricant is urged towards the sealed side of the chamber and therefore not lost.
It is a challenge to provide centrifuges with high rotational speeds, for example for low volumes that have a long lifetime.
The invention is based on the problem of improving the known centrifuges such that the lifetime of the known centrifuge is achieved.
The above-noted problem is solved by the features of the characterizing part of claim 1.
The main realization of the present invention is that in an arrangement as in EP 4 321 255 A1 , high rotational speeds of the drum can lead to a loss of lubricant through the seal of the bearings. That is, even if the seal is connected to an outer race of the bearing and the direction of centrifugal force is towards the outer race of the bearing and therefore towards the sealed side and away from a space between the seal and an inner race of the bearing, lubricant can still leave the bearing. Having identified this problem, a solution has been found in providing a further sealing outside the bearing and thereby catching the released lubricant and keeping it near the bearing. This solution is significantly easier to manufacture and cheaper than improving the sealing of the bearing, in particular taking into account that commercial bearings often have sealings clipped onto the outer race. For usual applications, these provide enough sealing and only subjecting the whole bearing to strong centrifugal forces allows the lubricant to leave the bearing through the clipped connection between outer race and sealing, leading to premature failure of the bearings. Exemplarily, in experiments, bearings have failed after 200 hours to 400 hours of use due to lost lubricant, which is a very short time for a bearing.
In detail, it is proposed that the outer wall comprises a ridge connected to the outer wall by a connection providing a sealing-function and extending from the outer wall towards the inner races along the sealing.
A preferred embodiment according to claim 2 relates to a feeding pipe for the rotor in which tubes may be placed. The feeding pipe of this embodiment helps provide an anti-twisting mechanism, however, because the feeding pipe rotates around the rotor, driving the rotor via the motor is mechanically challenging. An end of the feeding pipe may define a front side of the centrifuge.
It is proposed in an embodiment according to claim 3 to mount a main shaft for the drum and the rotor of the centrifuge to a side located opposite the front side. In that case, the main shaft and the feeding pipe do not interfere with each other.
The centrifuge may comprise a rotor drive train between the motor and the rotor with a drive shaft connected to the drive roller bearings (claim 4). Preferably, the drive shaft extends through the drum such that motor and rotor may be located on different sides of the drum functionally. In addition thereto, the bearing housing may be mounted onto the drum (claim 5) and the rotor drive shaft may extend completely through the bearing housing (claim 6). The bearing arrangement then may rotate with the feeding pipe, providing a solution to drive the rotor without interference with the feeding pipe.
According to claim 7, the drive bearing arrangement may comprise one or two rings screwed into the bearing housing for exerting an axial preload on the drive roller bearings. With a drive roller bearing subject to centrifugal force, the load on the drive roller bearings in the direction orthogonal to the bearing axes, i.e. in a direction pointing from one race to the other race may become balanced between a force exerted by the drive train, in particular tooth belts, and the centrifugal force. In this balanced state, especially regular ball bearings fail within hours as the balls without load slip. This happens because at two points of the circular motion trajectory of the balls, the balls move parallel to the centrifugal force. Providing an axial load for the bearings protects the drive roller bearings from this problem as there is always a load on the drive roller bearings. The angular ball bearings with an axial preload transfer the axial preload to the balls (claim 8).
In embodiments according to claim 9, the ridge may be formed integral with the outer wall, providing for a maximum sealing between the wall and the ridge and a simple production of the bearing housing. The ridge may also be formed by one of the rings. Providing a thread and a screwed connection between the bearing housing and the ring that provides sufficient sealing for the lubricant is usually not problematic as the lubricant does not move through most threads in relevant quantities. As the bearing housing may have two longitudinal sides with holes, it is preferably the case that both comprise a ridge, therefore a further ridge may be provided.
Between the ridge and/or the further ridge and the rotor drive shaft a space may be provided to avoid friction and leave room for mounting the rotor drive shaft (claim 10).
The ridge is preferably provided at least at the side to which the centrifugal force moves the lubricant, that being a side of the bearing housing furthest away from the common rotation axis (claim 11). For ease of production and to capture more grease, the ridge may extend around the bearing axis.
Claim 12 refers to preferred arrangements of the drive roller bearings in relation to the common rotation axis. Claim 13 refers to preferred arrangements of the sealing and the ring.
According to claim 14, a space is provided between the ridge and the closest roller bearing such that enough volume to collect the lubricant is provided.
Another teaching according to claim 15, which is of equal importance, relates to method of use of a proposed centrifuge, wherein the rotor and drum are rotated by the motor.
All explanations given with regard to the proposed centrifuge are fully applicable.
In the following, embodiments of the invention are explained with respect to the drawing. The drawing shows in

Fig. 1,: a fluidized bed centrifuge from the outside without an outer hous-ing,
Fig. 2,: a cut through Fig. 1,
Fig. 3,: the drive bearing arrangement in full (a)) and in a cut (b)) and the bearing housing (c)) and
Fig. 4,: an enlarged cut through the drive bearing arrangement and en-largements of the ridge and the further ridge.

Fig. 1 shows as a preferred embodiment a centrifuge 1 for continuous flow centrifugation. The centrifuge 1 is here and preferably usable for fluidized bed centrifugation. The outer view of Fig. 1 shows a front side of the centrifuge 1 with a closed door 2. The centrifuge 1 may comprise an outer housing not shown in Fig. 1.
Fig. 2 shows a longitudinal cut through the centrifuge 1 in Fig. 1 along the line marked with II. As can be seen, the centrifuge 1 comprises a drum 3, a rotor 4 and a motor 5 for driving the drum 3 and the rotor 4. The drum 3, driven by the motor 5, rotates around a common rotation axis A with a rotational frequency during use of the centrifuge 1. The rotational frequency here and preferably can be set arbitrarily by the user in a range leading up to for example a g-force of 2000g applied to a medium in the rotor 4.
The rotor 4 is coupled to the drum 3. Due to being coupled to the drum 3, the rotor 4, driven by the motor 5, rotates around the common rotation axis A with the double of the rotational frequency. It is a known principle that providing a ratio of 1:2 leads to an anti-twisting mechanism for tubes 6 feeding the rotor 4. The rotor 4 is preferably coupled mechanically to the drum 3, though a software coupling is conceivable. The mechanical coupling ensures that the rotational frequencies of the drum 3 and the rotor 4 keep the ratio of 1:2 without high precision sensors and software, such that the anti-twisting mechanism works.
Shown in the bottom part of Fig. 2 and shown in more detail in Figs. 3 and 4, the centrifuge 1 comprises a drive bearing arrangement 7. The drive bearing arrangement 7 comprises at least two drive roller bearings 8, here and preferably four ball bearings. With reference to Fig. 3 b), which shows a cut through the drive bearing arrangement 7 in Fig. 3 a), and Fig. 4, the drive roller bearings 8 each comprise an inner race 9, an outer race 10 and a bearing axis B. The races 9, 10 of the outer ball bearings are visible in more detail in Fig. 4.
Using the known working principle of roller bearings, one of said races 9, 10 is connected to the drum 3 and one of said races 9, 10 is connected to the rotor 4. The drive bearing arrangement 7 therefore provides a connection between the drum 3 and the rotor 4 that allows for relative rotation between both.
The drive roller bearings 8 each comprise a lubricant, in particular grease. At least one of the drive roller bearings 8 comprises a sealing 11 separate from and connected to the outer race 10 and extending towards the inner race 9. Here and preferably at least the outer drive roller bearings 8 comprise a sealing 11 at their outer sides. More preferably and also realized here is that each drive roller bearing 8 comprises two sealings 11. Such sealings 11 are well known in the art and often clipped onto the outer races 10, a solution usually providing for enough sealing-functionality for usual use cases. It is also known that the sealings 11 usually, as is preferably the case here, do not reach the inner race 9, which would create friction and possibly wear down the sealing 11. The opening between the inner race 9 and the sealing 11 may lead to a loss of lubricant, which however is tolerable and not the focus here.
It is proposed that the bearing axes B of the drive roller bearings 8 are each located spaced apart from, and in particular parallel to, the common rotation axis A, such that the drive roller bearings 8 rotate around the common rotation axis A. The term "spaced apart" here means that the bearing axes B and the common rotation axis A do not intersect at least within the respective roller bearing. Preferably, they do not intersect within the drive bearing arrangement 7, more preferably within the centrifuge 1 and more preferably never. The bearing axes B and the common rotation axis A may be parallel. The distance between the bearing axis B of each drive roller bearing 8 and the common rotation axis A may be greater than a radius or diameter of the drive roller bearing 8.
The drive roller bearings 8 may be significantly spaced apart from the common rotation axis A, leading to a strong centrifugal force acting on the drive roller bearings 8 as a whole. That is usually not the case for common uses of roller bearings. This centrifugal force leads to a loss of lubricant through the connection of the outer race 10 and the sealing 11. In Fig. 2, the centrifugal force acts on the drive bearing arrangement 7 in a direction pointing downwards. Keeping this direction in mind, in Figs. 3 and 4 the lubricant is forced downwards during rotation of the drum 3. The rotating outer race 10 and balls redistribute the lubricant within the drive roller bearings 8, however, some lubricant is pressed through the connection of the outer race 10 and the sealing 11 at the bottom side (outer side from the common rotation axis A) of the drive bearing arrangement 7. This generally happens for all four drive roller bearings 8, however, between two drive roller bearings 8 this is not problematic. At the outsides of the outer drive roller bearings 8 however, the lubricant may be lost.
As can also be seen, the drive bearing arrangement 7 comprises a bearing housing 12. The bearing housing 12 comprises an outer wall 13 rotationally fixed to the outer races 10 of the drive roller bearings 8. The connection between the outer races 10 and the outer wall 13 may be based on friction as the rotational forces on the outer races 10 will usually be rather low.
Essential is, that the outer wall 13 comprises a ridge 14 connected to the outer wall 13 by a connection providing a sealing-function and extending from the outer wall 13 towards the inner races 9 along the sealing 11. Figs. 2 to 4 show two ridges 14, a ridge 14 and a further ridge 14, on both longitudinal sides 15 of the bearing housing 12. Longitudinal sides 15 are the sides along a bearing axis B and preferably common rotation axis A, all of which axes are preferably parallel. The ridges 14 provide for a volume to collect the lubricant leaving the drive roller bearings 8 and keeping the lubricant close to the connection between outer race 10 and sealing 11. The loss of lubricant from the drive roller bearings 8 is therefore stopped and the lifetime of the drive roller bearings 8 increases greatly. The ridge 14 is here and preferably located outwards of one of the outer drive roller bearings 8 in the direction of the roller bearing axis B.
Here and preferably the centrifuge 1 comprises a feeding pipe 16 for continuously feeding the rotor 4 with a medium for centrifugation, which can be seen in Fig. 2. The feeding pipe 16 may be connected to the drum 3. The feeding pipe 16 preferably rotates around the common rotation axis A with the rotational frequency. The feeding pipe 16 leads along a back direction 17 of the centrifuge 1 around the rotor 4 and is connected to the drum 3 along a front direction 18 of the centrifuge 1, such that the feeding pipe 16 rotates around the rotor 4 around the common rotation axis A. As can be seen, the rotation of the feeding pipe 16 completely envelopes the rotor 4. In such an embodiment, to contact the rotor 4, only elements rotating synchronously with the feeding pipe 16 can be used. For that reason, the drive bearing arrangement 7 for driving the rotor 4 is connected to the drum 3. Preferably, the feeding pipe 16 takes in tubes 6 of a single-use tube set 19 connected to chambers 20 of the single-use tube set 19 and the rotor 4 takes in the chambers 20. The anti-twister mechanism aims at not intertwining these tubes 6. The chambers 20 may comprise a volume of at least 25 ml, preferably at least 50 ml, and/or, at most 200 ml, preferably at most 100 ml, more preferably exactly 50 ml, per chamber 20. The tube 6 set may comprise two or four or six chambers 20. The chambers 20 may also have a greater volume for example of 100 ml or 1000 ml.
As can be seen on the right side of Fig. 2, the centrifuge 1 may comprise a main shaft 21 defining the common rotation axis A. The main shaft 21 is mounted to a centrifuge housing 22, in particular at a side located in the back direction 17 from the drum 3 and the rotor 4, here at a back side 23, though it could also be mounted to a top side at the back of the centrifuge 1 or the like. The drum 3 and the rotor 4 are mounted onto the main shaft 21. The motor 5 may be mounted onto the centrifuge housing 22, too, here from the outside. A further outer housing is not shown. It can be seen that between the main shaft 21 and the rotor 4 and the drum 3, several main bearings 24 are located. These do not rotate around the main shaft 21 and are therefore not in the focus. The back direction 17 and front direction 18 are defined along the common rotation axis A. In principle, the directions are arbitrary and defined only by their functions. The front side may also be an upper side, for example.
The centrifuge 1 may comprise a rotor drive train 25 between the motor 5 and the rotor 4. The rotor drive train 25 comprises a rotor drive shaft 26 connected to one of the races 9, 10 of each drive roller bearing 8. Preferably, the rotor drive shaft 26 is connected, in particular directly, to the inner races 9 of the drive roller bearings 8 and the drum 3 is connected to the outer races 10 of the drive roller bearings 8 via the bearing housing 12. Further elements of the drive train will be explained in the following. In Fig. 3, the rotor drive shaft 26 is visible in a) and b). In Fig. 3 c), the bearing housing 12 is cut with the components of the rotor drive train 25 and the drive roller bearings 8 removed to allow a view inside the bearing housing 12 and in particular to show one embodiment of the ridge 14. Here and preferably, the rotor drive train 25 extends through the drum 3 via the rotor drive shaft 26. The mechanical coupling of the rotor 4 and the drum 3 is realized here by driving the rotor drive train 25 and the drum 3, via a drum drive train 27, by the same motor 5. It is then a question of gearing to synchronize the speeds with a factor of 1:2. For that, the rotor drive train 25 and the drum drive train 27 may comprise gearwheels 28, here belt wheels, in particular toothed belt wheels 29, with different sizes.
The rotor drive train 25 here and preferably leads to the rotor 4 from the back direction 17 of the centrifuge 1. Further, it is conceivable to connect the races 9, 10 the other way around, the inner races 9 being connected to the drum 3 and the outer races 10 to the rotor 4. The rotor drive shaft 26 may be a counter shaft with regard to the main shaft 21.
The connection or a connection between the housing and the drum 3 may be achieved by mounting the bearing housing 12 onto the drum 3. Preferably, the bearing housing 12 is screwed to the drum 3.
It may be the case that the rotor drive shaft 26 extends completely through the bearing housing 12 from one longitudinal side 15 to another longitudinal side 15 of the bearing housing 12 along at least one of the bearing axes B and the rotor drive train 25 comprises drive elements 30 connected to the rotor drive shaft 26 at both longitudinal sides 15 of the bearing housing 12. Preferably, the drive elements 30 on both sides are belts, in particular tooth belts. In addition to the tooth belts, the rotor drive train 25 here and preferably comprises toothed belt wheels 29 on both longitudinal sides 15 of the bearing housing 12, one of them leading towards the motor 5 and one leading towards the rotor 4, here driving the rotor 4 directly. It can be seen that parts of the rotor drive train 25 rotate together with the feeding tube 6, enabling the rotation of the rotor 4 in spite of the feeding tube 6 enveloping the rotor 4. The belts may comprise mechanisms for adjusting the belt tension 31.
Turning from the general structure of the centrifuge 1 towards the drive bearing arrangement 7, it may be the case that the drive bearing arrangement 7 comprises a ring 32 screwed into the bearing housing 12 exerting an axial preload along at least one of the bearing axis B onto the drive roller bearings 8 (Fig. 3 b) and Fig. 4). Here and preferably, the drive bearing arrangement 7 comprises a further ring 33 screwed onto the rotor drive shaft 26 exerting an axial preload along at least one of the bearing axes B onto the drive roller bearings 8. More preferably, the axial preload can be adjusted by adjusting a tightening torque of the ring 32 and/or the further ring 33. One of the ring 32 and the further ring 33 may preload only the outer races 10 and the other only the inner races 9. The outer races 10 may contact each other and/or be pressed against an outer race ridge 34 of the bearing housing 12. The inner races 9 may contact each other and/or be pressed against an inner race ridge 35 of the rotor drive shaft 26. For screwing the ring 32 into the bearing housing 12, the bearing housing 12 may comprise a screw thread 36. For screwing the further ring 33 onto the rotor drive shaft 26, the rotor drive shaft 26 may comprise a screw thread 36.
As mentioned, here and preferably, the drive roller bearings 8 are ball bearings. Additionally or alternatively, the drive bearing arrangement 7 may comprise four drive roller bearings 8 and/or the drive roller bearings 8 may be angular ball bearings with an axial preload. Here and preferably and as shown in the enlarged sections in Fig. 4, the inner races 9 or outer races 10 of the angular ball bearings are angled and the respective other races 9, 10 are not angled. It may be the case that the inner races 9 and/or, as here, the outer races 10 of at least two angular ball bearings are angled in different directions (also visible in the enlarged sections in Fig. 4). The drive roller bearings 8 as ball bearings may be arranged in a TOT arrangement.
According to one embodiment it is proposed that the ridge 14 is formed integral with the outer wall 13, or, that the ridge 14 is formed by the ring 32. Here and preferably, the drive bearing arrangement 7 comprises a further ridge 14 and the further ridge 14 is also formed integral with the outer wall 13 or by the ring 32. As can be seen here, one ridge 14 is formed integral with the outer wall 13 (Fig. 4 on the left) and one ridge 14 is formed by the ring 32 (Fig. 4 on the right). Which of those is seen as the ridge 14 and which as the further ridge 14 is arbitrary. Preferably, the ridge 14 and the further ridge 14 are located at opposite longitudinal sides 15 of the bearing housing 12. If the ridge 14 is formed by the ring 32, the threaded connection may have the sealing-function simply by a tight fit between the ring 32 and the screw thread 36.
It can also be seen in Fig. 4 that here and preferably, the ridge 14 and/or the further ridge 14 extends from the outer wall 13 towards the rotor drive shaft 26, leaving a space between the ridge 14 and the rotor drive shaft 26. It may additionally or alternatively be the case that the ridge 14 and/or the further ridge 14 extends from the outer wall 13 towards the inner races 9 along the sealing 11 for at least 5 %, preferably at least 7 %, more preferably at least 10 %, even more preferably at least 15 %, even more preferably at least 20 %, even more preferably at least 30 %, even more preferably at least 40 %, even more preferably at least 50 %, and/or at most 90 %, preferably at most 80 %, of a distance between the outer race 10 and the inner race 9. The distance between the outer race 10 and the inner race 9 is measured as the diameter of the balls for ball bearings and as a distance between the contact surfaces for other roller bearings. These distances allow for catching the lubricant and at the same time leave enough room for mounting the rotor drive shaft 26. Here and preferably, the further ring 33 is located in the space between the ridge 14 and the rotor drive shaft 26.
In response to the direction of centrifugal force, the ridge 14 preferably extends from a side of the bearing housing 12 furthest away from the common rotation axis A towards the common rotation axis A. Here and preferably, the ridge 14 extends around at least one of the bearing axes B. This embodiment is easier to produce.
The bearing axes B may be parallel, in particular identical. Here and preferably, the common rotation axis A does not pass through the drive roller bearings 8 and/or does not pass through the bearing housing 12. The drive roller bearings 8 therefore rotate around the common rotation axis A as a whole.
According to one embodiment it is proposed that the connection formed between the bearing housing 12 and the ring 32 by screwing the ring 32 is sealed. For that, for example, the ring 32 may be screwed into a sealing-material. The sealing 11 may be clipped onto the outer race 10 of the drive roller bearing 8 comprising the sealing 11. Here and preferably, each drive roller bearing 8 comprises a sealing 11, in particular two sealings 11.
Here and preferably the ridge 14 is spaced apart from the drive roller bearing 8 closest to the ridge 14 along a direction of the bearing axis B of said drive roller bearing 8. Preferably, a distance between the ridge 14 and the drive roller bearing 8 closest to the ridge 14 along a direction of the bearing axis B is at least 2 %, preferably at least 5 %, of a width of said drive roller bearing 8 and/or at least 0.5 mm, preferably at least 0.8 mm. The distance may alternatively or additionally be at most 3 mm, preferably at most 2 mm and/or at most 20 % of a width of said drive roller bearing 8, preferably at most 10 % of a width of said drive roller bearing 8. The volume should be large enough but the lubricant should stay close to the drive roller bearings 8.
Another teaching which is of equal importance relates to a method of use of the proposed centrifuge 1, wherein the rotor 4 and drum 3 are rotated by the motor 5.
All explanations given with regard to the proposed centrifuge 1 are fully applicable.

Claims

Centrifuge for continuous flow centrifugation, wherein the centrifuge (1) comprises a drum (3), a rotor (4) and a motor (5) for driving the drum (3) and the rotor (4), wherein the drum (3), driven by the motor (5), rotates around a common rotation axis (A) with a rotational frequency during use of the centrifuge (1), wherein the rotor (4) is coupled to the drum (3), wherein due to being coupled to the drum (3), the rotor (4), driven by the motor (5), rotates around the common rotation axis (A) with the double of the rotational frequency, wherein the centrifuge (1) comprises a drive bearing arrangement (7), wherein the drive bearing arrangement (7) comprises at least two drive roller bearings (8), wherein the drive roller bearings (8) each comprise an inner race (9), an outer race (10) and a bearing axis (B), wherein one of said races (9, 10) is connected to the drum (3) and one of said races (9, 10) is connected to the rotor (4),
wherein the drive roller bearings (8) each comprise a lubricant, wherein at least one of the drive roller bearings (8) comprises a sealing (11) separate from and connected to the outer race (10) and extending towards the inner race (9),

wherein the bearing axes (B) of the drive roller bearings (8) are each located spaced apart from, and in particular parallel to, the common rotation axis (A), such that the drive roller bearings (8) rotate around the common rotation axis (A),

wherein the drive bearing arrangement (7) comprises a bearing housing (12), wherein the bearing housing (12) comprises an outer wall (13) rotationally fixed to the outer races (10) of the drive roller bearings (8),
characterized in
that the outer wall (13) comprises a ridge (14) connected to the outer wall (13) by a connection providing a sealing-function and extending from the outer wall (13) towards the inner races (9) along the sealing (11).
Centrifuge according to claim 1, characterized in that the centrifuge (1) comprises a feeding pipe (16) for continuously feeding the rotor (4) with a medium for centrifugation, that the feeding pipe (16) rotates around the common rotation axis (A) with the rotational frequency, that the feeding pipe (16) leads along a back direction (17) of the centrifuge (1) around the rotor (4) and is connected to the rotor (4) along a front direction (18) of the centrifuge (1), such that the feeding pipe (16) rotates around the drum (3) around the common rotation axis (A), preferably, that the feeding pipe (16) takes in tubes (6) of a single-use tube set (19) connected to chambers (20) of the single-use tube set (19) and that the rotor (4) takes in the chambers (20).
Centrifuge according to claim 1 or 2, characterized in that the centrifuge (1) comprises a main shaft (21) defining the common rotation axis (A), that the main shaft (21) is mounted to a centrifuge housing (22), in particular at a side located in the back direction (17) from the drum (3) and the rotor (4), and, that the drum (3) and the rotor (4) are mounted onto the main shaft (21).
Centrifuge according to one of the preceding claims, characterized in that the centrifuge (1) comprises a rotor drive train (25) between the motor (5) and the rotor (4), that the rotor drive train (25) comprises a rotor drive shaft (26) connected to one of the races (9, 10) of each drive roller bearing (8), preferably, that the rotor drive shaft (26) is connected, in particular directly, to the inner races (9) of the drive roller bearings (8) and that the drum (3) is connected to the outer races (10) of the drive roller bearings (8) via the bearing housing (12), more preferably, that the rotor drive train (25) extends through the drum (3) via the rotor drive shaft (26).
Centrifuge according to one of the preceding claims, characterized in that the bearing housing (12) is mounted onto the drum (3), preferably, that the bearing housing (12) is screwed to the drum (3).
Centrifuge according to claim 4 or 5, characterized in that the rotor drive shaft (26) extends completely through the bearing housing (12) from one longitudinal side (15) to another longitudinal side (15) of the bearing housing (12) along at least one of the bearing axes (B) and the rotor drive train (25) comprises drive elements (30) connected to the rotor drive shaft (26) at both longitudinal sides (15) of the bearing housing (12), preferably, that the drive elements (30) on both sides are belts, in particular tooth belts.
Centrifuge according to one of the preceding claims, characterized in that the drive bearing arrangement (7) comprises a ring (32) screwed into the bearing housing (12) exerting an axial preload along at least one of the bearing axis (B) onto the drive roller bearings (8), preferably, that the drive bearing arrangement (7) comprises a further ring (33) screwed onto the rotor drive shaft (26) exerting an axial preload along at least one of the bearing axis (B) onto the drive roller bearings (8), more preferably, that the axial preload can be adjusted by adjusting a tightening torque of the ring (32) and/or the further ring (33).
Centrifuge according to one of the preceding claims, characterized in that the drive roller bearings (8) are ball bearings, and/or, that the drive bearing arrangement (7) comprises four drive roller bearings (8), and/or, that the drive roller bearings (8) are angular ball bearings with an axial preload, preferably, that the inner races (9) or outer races (10) of the angular ball bearings are angled and the respective other races (9, 10) are not angled, and/or, that the inner races (9) and/or outer races (10) of at least two angular ball bearings are angled in different directions.
Centrifuge according to one of the preceding claims, characterized in that the ridge (14) is formed integral with the outer wall (13), or, that the ridge (14) is formed by the ring (32), and/or, that the drive bearing arrangement (7) comprises a further ridge (14) and that the further ridge (14) is formed integral with the outer wall (13) or by the ring (32), preferably, that the ridge (14) and the further ridge (14) are located at opposite longitudinal sides (15) of the bearing housing (12).
Centrifuge according to one of claims 4 to 9, characterized in that the ridge (14) and/or the further ridge (14) extends from the outer wall (13) towards the rotor drive shaft (26), leaving a space between the ridge (14) and the rotor drive shaft (26), and/or, that the ridge (14) and/or the further ridge (14) extends from the outer wall (13) towards the inner races (9) along the sealing (11) for at least 5 %, preferably at least 7 %, more preferably at least 10 %, even more preferably at least 15 %, even more preferably at least 20 %, even more preferably at least 30 %, even more preferably at least 40 %, even more preferably at least 50 %, and/or at most 90 %, preferably at most 80 %, of a distance between the outer race (10) and the inner race (9), and/or, that the further ring (33) is located in the space.
Centrifuge according to one of the preceding claims, characterized in that the ridge (14) extends from a side of the bearing housing (12) furthest away from the common rotation axis (A) towards the common rotation axis (A), preferably, that the ridge (14) extends around at least one of the bearing axes (B).
Centrifuge according to one of the preceding claims, characterized in that the bearing axes (B) are parallel, in particular identical, and/or, that the common rotation axis (A) does not pass through the drive roller bearings (8) and/or does not pass through the bearing housing (12).
Centrifuge according to one of the preceding claims, characterized in that the connection formed between the bearing housing (12) and the ring (32) by screwing the ring (32) is sealed, and/or,
that the sealing (11) is clipped onto the outer race (10) of the drive roller bearing (8) comprising the sealing (11), preferably, that each drive roller bearing (8) comprises a sealing (11), in particular two sealings (11).
Centrifuge according to one of the preceding claims, characterized in that the ridge (14) is spaced apart from the drive roller bearing (8) closest to the ridge (14) along a direction of the bearing axis (B) of said drive roller bearing (8), preferably, that a distance between the ridge (14) and the drive roller bearing (8) closest to the ridge (14) along a direction of the bearing axis (B) is at least 2 %, preferably at least 5 %, of a width of said drive roller bearing (8) and/or at least 0.5 mm, preferably at least 0.8 mm.
Method of use of a centrifuge (1) according to one of the preceding claims, wherein the rotor (4) and drum (3) are rotated by the motor (5).