(19)
(11)EP 2 898 954 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
14.08.2019 Bulletin 2019/33

(21)Application number: 15152185.3

(22)Date of filing:  22.01.2015
(51)Int. Cl.: 
B04B 9/00  (2006.01)
B04B 9/12  (2006.01)
B04B 9/04  (2006.01)
B04B 15/02  (2006.01)

(54)

Centrifugation systems with non-contact seal assemblies

Zentrifugiersysteme mit kontaktlosen Dichtungsanordnungen

Systèmes de centrifugation avec des ensembles d'étanchéité sans contact


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 22.01.2014 US 201461930173 P

(43)Date of publication of application:
29.07.2015 Bulletin 2015/31

(73)Proprietor: Alfa Wassermann, Inc.
West Caldwell, NJ 07006 (US)

(72)Inventors:
  • Spiegel, Kurt Michael
    Pearl River, NY 10965 (US)
  • Weiland, Eric Bernard
    Mount Tabor, NJ 07878 (US)

(74)Representative: Moore, Michael Richard et al
Keltie LLP No.1 London Bridge
London SE1 9BA
London SE1 9BA (GB)


(56)References cited: : 
US-A- 2 913 169
US-B2- 8 192 343
US-A- 3 502 954
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    1. Field of the Invention



    [0001] The present disclosure is related to centrifugation systems. More particularly, the present disclosure is related to centrifugation systems with improved non-contact seal assemblies.

    2. Description of Related Art



    [0002] Centrifugal separation is commonly used to separate a solution into its constituent parts based on the density of the constituents. Here, the centrifugation system creates a centrifugal force field by spinning the solution containing the constituents to be separated, thus causing the constituents of higher density to separate from the solution.

    [0003] Many different styles of centrifugation systems have been used and are typically classified by, among other things, the flow in the system (e.g., batch or continuous flow) and by the speed of the centrifugation (e.g., ultra-centrifugation). By way of example, common continuous ultra-centrifugation systems rotate the rotor at speeds of more than 40,500 revolutions per minute using pneumatic drives or electric drives.

    [0004] It has been determined by the present disclosure that some prior art centrifugation systems can experience undesired leakage of fluids into the electric motor, hydraulic drive, or pneumatic drive, causing premature failure.

    [0005] Accordingly, it has been determined that there is a need for centrifugation systems that overcome, alleviate, and/or mitigate one or more of the aforementioned and other deleterious effects of the prior art systems.

    SUMMARY



    [0006] A centrifugation system is provided that has a non-contact seal assembly to mitigate leakage of fluids. In accordance with the invention, there is provided a centrifugation system comprising: a drive assembly having an upper housing and a lower housing separated by a top bearing plate with a rotor opening defined therein, the lower housing having a drive disposed therein with a rotor shaft aligned with the rotor opening; a non-contact seal assembly; and a tank assembly having a centrifuge rotor rotatably housed therein, wherein the non-contact seal assembly is characterized in that it comprises an upper guard and a skirted pivot, the upper guard being secured to the top bearing plate at the rotor opening so that the skirted pivot is operatively coupled to the rotor shaft for rotation without contacting the upper guard and so that the upper guard and the skirted pivot form a labyrinth seal to mitigate leakage of fluid from the upper housing through the rotor opening into the drive in the lower housing; and the tank assembly being connectable to the lower housing so that the centrifuge rotor is rotatably driven by the rotor shaft via the skirted pivot.

    [0007] In some embodiments, the non-contact seal assembly includes a lower guard having one or more capillary channels defined therein.

    [0008] In other embodiments, the non-contact seal assembly includes a pressure source that maintains a gas flow in a direction that is counter to a leaking flow.

    [0009] A centrifugation system is provided that has a non-contact seal assembly including an upper guard and a skirted pivot. In some embodiments, a pressure source that provides a gas flow between the upper guard and a surface of the skirted pivot is further provided. In some embodiments, the non-contact seal assembly further includes a lower guard having one or more capillary channels defined on an upper surface.

    [0010] A centrifugation system is provided that includes a drive assembly, a non-contact seal assembly, and a tank assembly. The drive assembly has an upper housing and a lower housing separated by a top bearing plate with a rotor opening defined therein. The lower housing has a drive disposed therein with a rotor shaft aligned with the rotor opening. The non-contact seal assembly has an upper guard and a skirted pivot. The non-contact seal assembly is secured to the top bearing plate at the rotor opening so that the skirted pivot is operatively coupled to the rotor shaft for rotation without contacting the upper guard with the upper guard and the skirted pivot forming a labyrinth seal to mitigate leakage of fluid from the upper housing through the rotor opening into the drive in the lower housing. The tank assembly has a centrifuge rotor rotatably housed therein. The tank assembly is connectable to the lower housing so that the centrifuge rotor is rotatably driven by the drive via the skirted pivot.

    [0011] In some embodiments, the drive is a pneumatic or an electric drive.

    [0012] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the centrifugation system can further include a pressure source providing a gas flow between a lower surface of the upper guard and an upper surface of the skirted pivot. Suitably, the gas flow has a direction opposite to a fluid leaking direction through the rotor opening.

    [0013] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the pressure source is sufficient to remove heat from the drive.

    [0014] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the pressure source is a positive or negative pressure source.

    [0015] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the centrifugation system can further include a lower guard secured to the upper guard with the skirted pivot rotatably positioned therebetween without contacting the upper or lower guards.

    [0016] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the lower guard includes a capillary channel defined on an upper surface. In preferred embodiments, the capillary channel is sloped away from the rotor opening.

    [0017] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the upper surface of the skirted pivot has an outer dimension that is larger than an inner dimension of an opening within the lower guide.

    [0018] The upper surface may have an angle with respect to a vertical axis through a central axis of the skirted pivot, the angle being sufficient so that fluid captured on the skirted pivot is guided towards the outer dimension.

    [0019] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the skirted pivot forms a wear point at a tip of the rotor shaft of the drive.

    [0020] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the skirted pivot is removably received in the non-contact seal assembly so that the skirted pivot is replaceable.

    [0021] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the centrifugation system can further include one or more features on seal surfaces of the upper guard and/or skirted pivot. Preferably, the one or more features form fluid vortices within the non-contact seal assembly sufficient to mitigate leakage of the fluid from the upper housing through the rotor opening into the drive in the lower housing.

    [0022] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the centrifugation system can further include a pressure source providing a gas flow between a lower surface of the upper guard and an upper surface of the skirted pivot, the gas flow having a direction opposite to a fluid leaking direction through the rotor opening.

    [0023] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the gas flow is sufficient to overcome any vortices and/or pressure differentials generated by the rotation of the skirted pivot.

    [0024] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the bearing plate is sloped away from the rotor opening so that fluid captured by and exiting the non-contact seal assembly is directed to an outer periphery.

    [0025] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the bearing plate further comprises an outlet port at the outer periphery through which fluid can be evacuated from the drive assembly.

    [0026] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the centrifugation system may further include an evacuation pump providing a gas flow between a lower surface of the upper guard and an upper surface of the skirted pivot. Preferably, the gas flow has a direction opposite to a fluid leaking direction through the rotor opening. In preferred embodiments, the evacuation pump may also evacuate fluid from the outlet port at the outer periphery.

    [0027] In some embodiments, a centrifugation system is provided that has a drive, a bearing plate, a non-contact seal assembly sealing, and a pressure source. The drive has a rotor shaft. The bearing plate has a rotor opening aligned with the rotor shaft. The non-contact seal assembly seals the rotor opening and includes an upper guard and a skirted pivot. The skirted pivot is connected to the rotor shaft for rotation by the drive without contacting the upper guard. The pressure source provides a gas flow between a lower surface of the upper guard and an upper surface of the skirted pivot. Suitably, the gas flow has a direction opposite to a fluid leaking direction through the rotor opening.

    [0028] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the pressure source is a positive or negative pressure source.

    [0029] In other embodiments alone or in combination with one or more of the aforementioned or after-mentioned embodiments, the gas flow is sufficient to overcome any vortices and/or pressure differentials generated by the rotation of the skirted pivot.

    [0030] The above-described and other features and advantages of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0031] 

    FIG. 1 is a top perspective view of an exemplary embodiment of a centrifugation system according to the present disclosure;

    FIG. 2 is a top perspective view of a drive assembly in the system of FIG. 1;

    FIG. 3 is a partial exploded view of the drive assembly of FIG. 2;

    FIG. 4 is a top perspective view of an exemplary embodiment of a top bearing plate and seal assembly according to the present disclosure;

    FIG. 5 is a partial exploded top perspective view of the seal assembly of FIG. 4 illustrating the upper guard, the skirted pivot, and the lower guard;

    FIG. 6 is a partial exploded bottom perspective view of the seal assembly of FIG. 4;

    FIG. 7 is a sectional view of the seal assembly of FIG. 4;

    FIG. 8 is a sectional view of the drive assembly of FIG. 2 illustrating a gas flow;

    FIG. 9 is a magnified sectional view of the drive assembly of FIG. 2 illustrating the gas flow through the seal assembly;

    FIG. 10 is a top perspective view of the centrifugation system of FIG. 1 illustrating the gas flow;

    FIG. 11 is a top perspective view of the seal assembly of FIG. 4 having the upper guard removed to illustrate the skirted pivot and the lower guard;

    FIG. 12 is a bottom perspective view of an exemplary embodiment of the upper guard of the seal assembly;

    FIG. 13 is a bottom view of the upper guard of FIG. 12;

    FIG. 14 is a top perspective view of the upper guard of FIG. 12;

    FIG. 15 is a bottom perspective view of another exemplary embodiment of the upper guard of the seal assembly;

    FIG. 16 is a bottom view of the upper guard of FIG. 15;

    FIG. 17 is a top perspective view of the upper guard of FIG. 15;

    FIG. 18 is a bottom view of another exemplary embodiment of an upper guard according to the present disclosure;

    FIG. 19 is a bottom view of another exemplary embodiment of an upper guard according to the present disclosure;

    FIG. 20 is a bottom view of yet another exemplary embodiment of an upper guard according to the present disclosure;

    FIG. 21 is a bottom view of still another exemplary embodiment of an upper guard according to the present disclosure;

    FIG. 22 is a partial sectional view of an exemplary embodiment of an upper guard according to the present disclosure;

    FIG. 23 is a partial section view of another exemplary embodiment of an upper guard according to the present disclosure;

    FIG. 24 is a partial sectional view of yet another exemplary embodiment of an upper guard according to the present disclosure;

    FIG. 25 is a partial sectional view of still another exemplary embodiment of an upper guard according to the present disclosure; and

    FIG. 26 is a partial sectional view of an embodiment of an upper guard and skirted pivot according to the present disclosure.


    DETAILED DESCRIPTION



    [0032] Referring to the drawings and in particular to FIG. 1, an exemplary embodiment of a centrifugation system according to the present disclosure is shown and is generally referred to by reference numeral 10.

    [0033] Centrifugation system 10 (hereinafter "system") includes a base or stand 12, a centrifugation tank assembly 14, a drive assembly 16, and a lift assembly 18. In some embodiments, system 10 can also include a control interface 19 in electrical communication (e.g., wired, wireless, or combinations thereof) with, for example, drive assembly 16, lift assembly 18, and other components of the system described herein to allow the operator to control the various movements and operations of the system. Control interface 19 can be any human-machine-interface (HMI) such as, but not limited to, a touch screen that allows the operator to control the various components of system 10.

    [0034] Advantageously, system 10 includes a non-contact seal assembly configured to mitigate leakage of fluids within drive assembly 16.

    [0035] For purposes of clarity, system 10 is described herein as an ultra-centrifugation system and drive assembly 16 is described as an electric drive such that the non-contact seal assembly mitigates leakage into the electric drive. Of course, it is contemplated by the present disclosure for the non-contact seal assembly to find equal use in any device having any type of device, which has a need for a non-contact seal assembly.

    [0036] Except as described herein below, base 12, centrifugation tank assembly 14, drive assembly 16, and lift assembly 18 may function as disclosed in Applicant's own U.S. Patent No. 8,192,343. Lift assembly 18 is configured to move drive assembly 16 with respect to tank assembly 14. In some embodiments, lift assembly 18 is a two-axis lift that is configured to, under the control of the operator via interface 19, lift and remove drive assembly 16 from tank assembly 14. However, it is also contemplated by the present disclosure for lift assembly 18 to be a single-axis lift or a three-axis lift as desired.

    [0037] Referring now to FIGS. 2 and 3, drive assembly 16 is described in more detail. Drive assembly 16 includes an upper housing 20 and a lower housing 22 separated by a top bearing plate 24. Lower housing 22 includes the rotor and stator of the electric drive such that sealing the lower housing from fluid within upper housing 20 is desired. Specifically, it is desired to prevent fluid within upper housing 20 from passing through a rotor opening 26 in top bearing plate 24 and into lower housing 22. Accordingly, drive assembly 16 includes a non-contact seal assembly 30, which mitigates leakage of fluid from upper housing 20 through rotor opening 26 into lower housing 22.

    [0038] As will be described in more detail below with simultaneous reference to FIGS. 2-11, non-contact seal assembly 30, in some embodiments, has an upper guard 32 and a skirted pivot 34 that form a labyrinth seal there between to mitigate leakage. The labyrinth seal reduces leakage past the seal without direct contact and wear between upper guard 32 and skirted pivot 34, which is not desired at the ultra-centrifugation speeds of system 10.

    [0039] Without wishing to be bound by any particular theory, the term "labyrinth seal" is used herein to define the seal formed by a seal area or chamber 36 of very small clearance defined between upper guard 32 and skirted pivot 34. This seal area 36 defines a tortuous path for any fluids, mitigating the passage of such fluids through opening 26. Additionally, it is believed that features (e.g., teeth, steps, spirals, etc.) on the seal surfaces of upper guard 32, skirted pivot 34, or both can, in some instances, form fluid vortices within the chamber 36 to further ensure that any liquid that enters the chamber becomes entrapped therein, ejected and/or acts as a barrier to prevent further fluid from entering the chamber.

    [0040] Skirted pivot 34 can function as a wear point at the tip of a rotating shaft of drive assembly 16. This allows the user to replace the skirted pivot 34 instead of the whole shaft when wear or damage occurs.

    [0041] In some embodiments in combination with the aforementioned labyrinth seal or as a standalone feature, system 10 can be configured to provide a gas flow 40 through chamber 36 in a direction opposite to the leaking direction to mitigate such leakage. When present, this counter gas flow 40 can provide the added benefit of removing heat (e.g., cooling) from the drive assembly 16 and, hence, removing heat or at least mitigation heat load on product within system 10.

    [0042] In still other embodiments in combination with one or both of the aforementioned labyrinth seal and the forced gas flow 40 or as a standalone feature, the non-contact seal assembly 16 includes a lower guard 42. The lower guard 42 can include one or more capillary channels 44 defined on an upper surface 46, which may assist in collecting any fluid - particularly minute fluid amounts - that may pass through the non-contact seal assembly and direct that collected fluid away from region to be protected - namely opening 26.

    [0043] During assembly, skirted pivot 34 is assembled between upper and lower guards 32, 42 with the guards sealingly secured to bearing plate 24. For example, upper and lower guards 32, 42 can be sealingly secured to bearing plate 24 with one or more o-rings 50 (two shown) by one or more fasteners 52 (three shown) as seen in FIGS. 3-4.

    [0044] Once assembled, upper and lower guards 32, 42 are mounted to bearing plate 24 so that the guards remain stationary (i.e., do not rotate) during operation of drive assembly 16. Additionally once assembled, skirted pivot 34 is rotatably positioned between guards 32, 42 to define labyrinth seal chamber 36 between an upper surface 54 of the skirted pivot and a lower surface 56 of upper guard 32.

    [0045] In this manner, upper guard 32 acts as a "stator" or "stationary part" of the labyrinth seal, while skirted pivot 34 is operatively coupled to drive assembly 16 to act as a "rotor" or "moving part" of the labyrinth seal.

    [0046] Bearing plate 24 is, in some embodiments such as that shown in FIGS. 2-4, sloped away from opening 26 and seal assembly 30 so that fluid captured by and exiting the seal assembly at channels 44 is directed to an outer periphery 60. Preferably, bearing plate 24 further includes an outlet port 62 at outer periphery 60 through which collected fluid can be evacuated or removed from drive assembly 16.

    [0047] As shown in FIGS. 8-10, system 10 can include pump 64 in fluid communication with upper housing 20 via an outlet port 66 and a conduit 68 to provide gas flow 40 through chamber 36. Pump 64 can be in electrical communication with control interface 19 to allow operator control of the pump. Further, pump 64 can be in electrical communication with drive assembly 16 so that the pump is controlled based on the operation of the drive. In this embodiment, pump 64 is illustrated as a vacuum pump that draws ambient air as gas flow 40. Pump 64 draws the air through conduit 68, outlet port 66, seal assembly 30, opening 26, and through an inlet port 70 in lower housing 22.

    [0048] Simply stated, system 10 has a leakage direction 72 in the direction of gravity, namely from upper housing 20 towards lower housing 22 - where the stator and rotor of the electric motor in drive assembly 16 is within the lower housing. Advantageously, system 10 may establish gas flow 40 in a direction 74 opposite or counter to the leakage direction 72.

    [0049] While outlet and inlet ports 66, 70 are shown by way of example as being in upper and lower housings 20, 22, respectively, it is contemplated by the present disclosure for the ports to be anywhere within drive assembly 16 that permits gas flow 40 to flow through chamber 36 in counter direction 74.

    [0050] It should also be recognized that system 10 is described by way of example with pump 64 establishing flow 40 using a vacuum of air (e.g., negative pressure). Of course, it is contemplated by the present disclosure for system 10 to establish flow 40 using any gas. Moreover, it is contemplated by the present disclosure for system 10 to establish flow 40 using a positive pressure gas source that forces the gas from inlet port 70 towards outlet port 66 or a combination of positive and negative pressure sources.

    [0051] System 10 is illustrated collecting fluid from pump 64 in a collection chamber. In some embodiments, system 10 can include a sensor (not shown) in conduit 68, the collection chamber, and/or anywhere within seal assembly 26 or drive assembly 16 to detect leakage. For example, system 10 can include a volume sensor in the collection chamber such that once fluid of a certain volume is detected, the system can generate an alarm to the user to perform a system check or other remedial action. In another example, system 10 can include a flow rate sensor in the conduit 68 such that once fluid of a certain flow rate is detected and is indicative of a failure, the system can generate an alarm to the user to perform a system check or other remedial action.

    [0052] Additionally, in some embodiments, gas flow 40 can also provide the added benefit of removing heat (e.g., cooling) the drive assembly 16 and, hence, removing heat or at least mitigation heat load on product within system 10.

    [0053] In some embodiments, system 10 works as a low pressure system such as under 5 pounds per square inch (psi), and high mass air flow such as over 650 milliliters per minute (mLPM). Of course, it is contemplated by the present disclosure for system 10 to provide gas flow 40 at any desired pressure or flow volume.

    [0054] In some embodiments, system 10 is configured to establish gas flow 40 at different levels depending on the rotational speed of centrifuge system 10. For purposes of brevity, system 10 is described herein below establishing gas flow 40 at only two different levels, namely at a high speed and at a low speed. Of course, it is contemplated by the present disclosure for system 10 to variably control pump 64 according to the speed of drive assembly 16 in discrete increments or continuously.

    [0055] In some embodiments, at lower speeds of drive assembly 16, system 10 controls pump 64 so that air flow 40 is not generated. Rather during slower speeds, seal assembly 30 relies upon the slope and radial dimension of skirted pivot 34 and lower guide 42 as shown in FIGS. 7, 9, and 11 to guide liquid leaking from upper housing 20 radially outward away from opening 26.

    [0056] Skirted pivot 34 has upper surface 54 defined on a skirt 80, which has an outer dimension that is larger than an inner dimension of the opening within lower guide 42 (FIG. 7). Additionally, skirt 80 is configured so that upper surface 54 has an angle 82 with respect to a vertical axis 84 through the central axis of skirted pivot 32. Angle 82 is preferably less than 90 degrees so that fluid captured on skirt 80 is guided towards an outer periphery 84 of the skirt.

    [0057] In this manner when system 10 is controlled so that drive assembly 16, and, thus, skirted pivot 32 are rotated at lower speeds the natural force of gravity and any centrifugal forces imparted on the captured fluid will cause fluid leaking through seal assembly 30 to be captured on skirt 80 and guided radially outward towards periphery 84. Moreover, any fluid that drips from outer periphery 84 of skirt 80 is received on lower guide 42.

    [0058] In some embodiments, to further assist guiding fluid collected on lower guard 42 away from opening 26, the lower guard may also be sloped away from the opening and towards its outer periphery 86. Moreover and as described above, lower guard 42 may include capillary channels 44 defined on upper surface 46, which assist in collecting any fluid and direct that collected fluid towards periphery 86 and out of the channels at openings 88.

    [0059] Furthermore, in some embodiments opening 26 and lower guard 42 are configured to allow air flow generated by the rotation of the motor within drive assembly 16 to flow upward into the space 90 below skirt 80. As shown in FIG. 11, this air flow travels up the curved lower surface 92 of the skirt and is directed outward so that any fluid falling from the periphery 84 of the skirt pushed radially outward from the periphery of the skirt.

    [0060] Still further, in some embodiments the rotation of upper surface 54 of skirted pivot 34 with respect to lower surface 56 of upper guard 32 - even at the slower speeds - is believed to generate vortices and/or pressure differentials within chamber 36 to mitigate leakage of fluid onto skirt 80.

    [0061] Thus, in some embodiments, at slower speeds, seal assembly 30 forms a labyrinth seal in chamber 36 that mitigates fluid from entering or bypassing the chamber. Then, seal assembly 30 is further configured, due to the slope of upper surface 54 of skirt 80 and the airflow from the motor, to guide fluid that does bypass chamber 36 radially outward off the periphery 84 of the skirt. Finally, seal assembly 30 is further configured, due to channels 44 and the slope of lower guard 42, to guide fluid that falls off periphery 84 of skirt 80 radially outward towards periphery 86 of the lower guard, out of outlets 88, and then onto top bearing plate 24. Again, bearing plate 24 is preferably also sloped away from opening 26 and seal assembly 30 so that fluid captured by and exiting the seal assembly at channels 44 is directed to outer periphery 60 and evacuated or removed from drive assembly 16 at outlet 66.

    [0062] In sum, in some embodiments, system 10 is configured so that when pump 64 is not controlled to generate gas flow 40 the drive assembly 16 provides a three-way cascading configuration that is aided by the vortices and/or pressure differentials generated by seal assembly 16 in chamber 36 and by the air pressure from the motor in lower housing 22 to mitigate leakage of fluid through opening 26.

    [0063] However, system 10 may also be configured to control pump 64 to generate gas flow 40 as needed.

    [0064] For example, system 10 may be configured so that the operator can selectively turn the pump 64 on and off as desired.

    [0065] Alternately, system 10 can be configured so that when drive assembly 16 rotates at higher speeds, such as for example above 10,000 revolutions per minute (RPM), the system controls pump 64 to generate gas flow 40.

    [0066] In other embodiments, system 10 may include a fluid cooling system 94 as shown in FIG. 8, which provides cooling to drive assembly 16, such as described in Applicant's U.S. Patent No. 8,192,343. In these embodiments, cooling system 94 pumps coolant into upper housing 20 via a first conduit 96 and returns the coolant via a second conduit 98. In this manner, cooling system 94 is configured to cool components within upper housing 20 in a known manner. In some embodiments, cooling system 94 may be in electrical communication with control interface 19. Thus, in some embodiments, system 10 may be configured to control pump 64 to generate gas flow 40 based on the activation of cooling system 94 - namely to provide the gas flow when the risk of a leak in the activated cooling system within upper housing 20 is present.

    [0067] Preferably, gas flow 40 is sufficient to overcome any vortices and/or pressure differentials generated in labyrinth seal chamber 36 by the rotation of upper surface 54 and lower surface 56 and to cause the air flow to pass through the chamber. Thus, suitably, gas flow 40 is believed to be sufficient to mitigate any fluid from traveling through chamber 36.

    [0068] Without wishing to be bound by any particular theory, the pressure differentials and/or vortices within the labyrinth chamber 36 at the higher speeds are believed to become either sufficiently steady or unsteady that well-defined voids within the fluid flow patterns develop. These well-defined voids can allow leakage through the seal assembly 30. However since in preferred embodiments counter gas flow 40 provides a flow through chamber 36 at these high speeds, the gas flow 40 is believed to overcome, modify, or at least fill the voids in the fluid flow patterns within the chamber so as to mitigate leakage of fluid into and/or through the chamber.

    [0069] Upper and lower guards 32, 42 may suitably be made of any desired material such as, but not limited to, polyether ether ketone (PEEK) or some other polymer material so that if accidental contact is made with skirted pivot 34, the guards and/or pivot wear without disrupting the operation of the motor.

    [0070] Referring now to FIGS. 12-25, various exemplary embodiments of the features present on upper guard 32 sufficient to generate the desired labyrinth seal vortices and/or pressure differentials are shown. FIGS. 12-14 illustrate a plurality of cylindrical cuts in lower surface 56. FIGS. 15-17 illustrate a helix cut in lower surface 56.

    [0071] FIG. 18 illustrates a series of linear spoke-like features on lower surface 56, while FIG. 19 illustrates a series of non-linear spoke-like features on the lower surface. FIG. 20 illustrates a series of non-random features on lower surface 56, while FIG. 21 illustrates a series of random features on the lower surface. In the embodiments of FIGS. 18-21, the features can be cut or recessed into lower surface 56, can protrude from the lower surface, or combinations thereof.

    [0072] FIG. 22 illustrates a pattern of polygonal teeth cut into lower surface 56. FIG. 23 illustrates a regular pattern of wavy or curved teeth cut into lower surface 56, while FIG. 24 illustrates a non-regular pattern of wavy or curved teeth cut into the lower surface. FIG. 25 illustrates a planar or flat lower surface 56.

    [0073] It should be recognized that seal assembly 30 has been described above by way of example having features present on lower surface 56 of upper guard 32 that generate the vortices and/or pressure differentials in chamber 36. Of course, it is contemplated by the present disclosure for these features to be present on upper surface 54 of skirted pivot 34. Moreover, it is contemplated by the present disclosure for the features to be present on both lower and upper surfaces 54, 56 as illustrated in FIG. 26.

    [0074] In embodiments where the features are present on upper surface 54 of skirted pivot 34, it is preferred that such features have radial channels (not shown) defined therein - similar to channels 44 on lower guard 42 - to guide any fluid on the upper surface towards outer periphery 84.

    [0075] It should also be noted that the terms "first", "second", "third", "upper", "lower", and the like may be used herein to modify various elements. These modifiers do not imply a spatial, sequential, or hierarchical order to the modified elements unless specifically stated.

    [0076] While the present disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure. Therefore, it is intended that the present disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated, and the scope of the invention is defined by the appended claims.


    Claims

    1. A centrifugation system (10) comprising:

    a drive assembly (16) having an upper housing (20) and a lower housing (22) separated by a top bearing plate (24) with a rotor opening (26) defined therein, the lower housing (22) having a drive disposed therein with a rotor shaft aligned with the rotor opening (26);

    a non-contact seal assembly; and

    a tank assembly (14) having a centrifuge rotor rotatably housed therein, wherein the non-contact seal assembly (30) is characterized in that it comprises an upper guard (32) and a skirted pivot (34), the upper guard (32) being secured to the top bearing plate (24) at the rotor opening (26) so that the skirted pivot (34) is operatively coupled to the rotor shaft for rotation without contacting the upper guard (32) and so that the upper guard (32) and the skirted pivot (34) form a labyrinth seal to mitigate leakage of fluid from the upper housing (20) through the rotor opening (26) into the drive in the lower housing (22); and the tank assembly (14) being connectable to the lower housing (22) so that the centrifuge rotor is rotatably driven by the rotor shaft via the skirted pivot (34) .


     
    2. The centrifugation system of claim 1, wherein the drive is a pneumatic or an electric drive.
     
    3. The centrifugation system of claim 1 or claim 2, further comprising a lower guard (42) secured to the upper guard (32) with the skirted pivot (34) rotatably positioned therebetween without contacting the upper (32) or lower (42) guards.
     
    4. The centrifugation system of claim 3, wherein the lower guard (42) comprises a capillary channel (44) defined on an upper surface (46), preferably the capillary channel (44) being sloped away from the rotor opening (26).
     
    5. The centrifugation system of claim 3 or claim 4, wherein the upper surface (54) of the skirted pivot (34) has an outer dimension that is larger than an inner dimension of an opening within the lower guide (42).
     
    6. The centrifugation system of any of claims 1 to 5, wherein the skirted pivot (34) forms a wear point at a tip of the rotor shaft of the drive.
     
    7. The centrifugation system of any of claims 1 to 6, wherein the skirted pivot (34) is removably received in the non-contact seal assembly (30) so that the skirted pivot (34) is replaceable.
     
    8. The centrifugation system of any of claims 1 to 7, further comprising one or more features on seal surfaces of the upper guard (32) and/or skirted pivot (34), the one or more features forming fluid vortices within the non-contact seal assembly (30) sufficient to mitigate leakage of the fluid from the upper housing (20) through the rotor opening (26) into the drive in the lower housing (22).
     
    9. The centrifugation system of any of claims 1 to 8, further comprising a pressure source (64) providing a gas flow (40) between a lower surface (56) of the upper guard (32) and an upper surface (54) of the skirted pivot (34), the gas flow (40) having a direction opposite to a fluid leaking direction through the rotor opening (26).
     
    10. The centrifugation system of claim 9, wherein the pressure source (64) is sufficient to remove heat from the drive.
     
    11. The centrifugation system of claim 9 or claim 10, wherein the pressure source (64) is a positive or negative pressure source.
     
    12. The centrifugation system of any of claims 9 to 11, wherein the gas flow (40) is sufficient to overcome any vortices and/or pressure differentials generated by the rotation of the skirted pivot (34).
     
    13. The centrifugation system of any of claims 1 to 12, wherein the bearing plate (24) is sloped away from the rotor opening (26) so that fluid captured by and exiting the non-contact seal assembly (30) is directed to an outer periphery (60).
     
    14. The centrifugation system of any of claims 1 to 13, wherein the bearing plate (24) has an outlet port (62) at an outer periphery (60) through which fluid can be evacuated from the drive assembly (16).
     
    15. The centrifugation system of claim 14, further comprising an evacuation pump, the evacuation pump providing a gas flow between a lower surface (56) of the upper guard (32) and an upper surface (54) of the skirted pivot (34), the gas flow having a direction opposite to a fluid leaking direction through the rotor opening (26), and the evacuation pump evacuating fluid from the outlet port (62) at the outer periphery (60).
     


    Ansprüche

    1. Zentrifugationssystem (10), umfassend:

    eine Antriebsbaugruppe (16) mit einem oberen Gehäuse (20) und einem unteren Gehäuse (22), die durch eine obere Lagerplatte (24) mit einer darin gebildeten Rotoröffnung (26) getrennt sind, wobei das untere Gehäuse (22) einen darin untergebrachten Antrieb mit einer Rotorwelle, die mit der Rotoröffnung (26) ausgerichtet ist, aufweist;

    eine berührungslose Dichtungsbaugruppe und

    eine Behälterbaugruppe (14) mit einem darin drehbar untergebrachten Zentrifugenrotor, wobei die berührungslose Dichtungsbaugruppe (30) dadurch gekennzeichnet ist, dass sie einen oberen Schutz (32) und einen Drehzapfen mit Kragen (34) umfasst, wobei der obere Schutz (32) an der oberen Lagerplatte (24) an der Rotoröffnung (26) befestigt ist, so dass der Drehzapfen mit Kragen (34) betriebsfähig mit der Rotorwelle gekoppelt ist, so dass er sich dreht, ohne den oberen Schutz (32) zu berühren, und so, dass der obere Schutz (32) und der Drehzapfen mit Kragen (34) eine Labyrinthdichtung bilden, die das Austreten von Fluid aus dem oberen Gehäuse (20) durch die Rotoröffnung (26) in den Antrieb im unteren Gehäuse (22) abschwächt; und wobei die Behälterbaugruppe (14) mit dem unteren Gehäuse (22) verbindbar ist, so dass der Zentrifugenrotor durch die Rotorwelle über den Drehzapfen mit Kragen (34) drehend angetrieben wird.


     
    2. Zentrifugationssystem nach Anspruch 1, wobei der Antrieb ein pneumatischer oder ein elektrischer Antrieb ist.
     
    3. Zentrifugationssystem nach Anspruch 1 oder Anspruch 2, das ferner einen unteren Schutz (42) umfasst, die am oberen Schutz (32) befestigt ist, wobei der Drehzapfen mit Kragen (34) drehbar dazwischen angeordnet ist, ohne den oberen (32) oder den unteren Schutz (42) zu berühren.
     
    4. Zentrifugationssystem nach Anspruch 3, wobei der untere Schutz (42) einen Kapillarkanal (44) umfasst, der auf einer oberen Fläche (46) gebildet ist, wobei der Kapillarkanal (44) vorzugsweise von der Rotoröffnung (26) weg geneigt ist.
     
    5. Zentrifugationssystem nach Anspruch 3 oder Anspruch 4, wobei die obere Fläche (54) des Drehzapfens mit Kragen (34) eine äußere Abmessung besitzt, die größer ist als eine innere Abmessung einer Öffnung in der unteren Führung (42).
     
    6. Zentrifugationssystem nach einem der Ansprüche 1 bis 5, wobei der Drehzapfen mit Kragen (34) eine Verschleißstelle an einer Spitze der Rotorwelle des Antriebs bildet.
     
    7. Zentrifugationssystem nach einem der Ansprüche 1 bis 6, wobei der Drehzapfen mit Kragen (34) in der berührungslosen Dichtungsbaugruppe (30) entnehmbar aufgenommen ist, so dass der Drehzapfen mit Kragen (34) austauschbar ist.
     
    8. Zentrifugationssystem nach einem der Ansprüche 1 bis 7, das ferner eine oder mehrere Besonderheiten auf Dichtungsflächen des oberen Schutzes (32) und/oder des Drehzapfens mit Kragen (34) umfasst, wobei die eine oder die mehreren Besonderheiten Fluidwirbel in der berührungslosen Dichtungsbaugruppe (30) bilden, die ausreichen, um das Austreten von Fluid aus dem oberen Gehäuse (20) durch die Rotoröffnung (26) in den Antrieb im unteren Gehäuse (22) abzuschwächen.
     
    9. Zentrifugationssystem nach einem der Ansprüche 1 bis 8, das ferner eine Druckquelle (64) umfasst, die einen Gasstrom (40) zwischen einer unteren Fläche (56) des oberen Schutzes (32) und einer oberen Fläche (54) des Drehzapfens mit Kragen (34) bereitstellt, wobei der Gasstrom (40) eine Richtung aufweist, die einer Fluidaustrittsrichtung durch die Rotoröffnung (26) entgegengesetzt ist.
     
    10. Zentrifugationssystem nach Anspruch 9, wobei die Druckquelle (64) ausreichend ist, um dem Antrieb Wärme zu entziehen.
     
    11. Zentrifugationssystem nach Anspruch 9 oder Anspruch 10, wobei die Druckquelle (64) eine Überdruck- oder Unterdruckquelle ist.
     
    12. Zentrifugationssystem nach einem der Ansprüche 9 bis 11, wobei der Gasstrom (40) ausreichend ist, um jegliche Wirbel und/oder Druckunterschiede, die durch die Drehung des Drehzapfens mit Kragen (34) erzeugt werden, zu überwinden.
     
    13. Zentrifugationssystem nach einem der Ansprüche 1 bis 12, wobei die Lagerplatte (24) von der Rotoröffnung (26) weg geneigt ist, so dass Fluid, das von der berührungslosen Dichtungsbaugruppe (30) aufgefangen wird und aus dieser austritt, zu einem äußeren Umfang (60) geleitet wird.
     
    14. Zentrifugationssystem nach einem der Ansprüche 1 bis 13, wobei die Lagerplatte (24) eine Auslassöffnung (62) an einem äußeren Umfang (60) besitzt, durch die Fluid aus der Antriebsbaugruppe (16) ausgeleitet werden kann.
     
    15. Zentrifugationssystem nach Anspruch 14, das ferner eine Evakuierungspumpe umfasst, wobei die Evakuierungspumpe einen Gasstrom zwischen einer unteren Fläche (56) des oberen Schutzes (32) und einer oberen Fläche (54) des Drehzapfens mit Kragen (34) bereitstellt, wobei der Gasstrom (40) eine Richtung aufweist, die einer Fluidaustrittsrichtung durch die Rotoröffnung (26) entgegengesetzt ist, und die Evakuierungspumpe Fluid von der Auslassöffnung (62) am äußeren Umfang (60) ausleitet.
     


    Revendications

    1. Système de centrifugation (10) comprenant :

    un ensemble d'entraînement (16) ayant un logement supérieur (20) et un logement inférieur (22) séparés par une plaque d'appui supérieure (24) avec une ouverture de rotor (26) définie dans celui-ci, le logement inférieur (22) ayant un entraînement placé dans celui-ci avec un arbre de rotor aligné avec l'ouverture de rotor (26) ;

    un ensemble d'étanchéité sans contact ; et

    un ensemble réservoir (14) ayant un rotor centrifuge logé en rotation dans celui-ci, dans lequel l'ensemble d'étanchéité sans contact (30) est caractérisé en ce qu'il comprend une protection supérieure (32) et un pivot chemisé (34), la protection supérieure (32) étant fixée à la plaque d'appui supérieure (24) à l'ouverture de rotor (26) de sorte que le pivot chemisé (34) est couplé de manière fonctionnelle à l'arbre de rotor pour une rotation sans contact avec la protection supérieure (32) et de sorte que la protection supérieure (32) et le pivot chemisé (34) forment un joint à labyrinthe pour atténuer une fuite de fluide du logement supérieur (20) à travers l'ouverture de rotor (26) dans l'entraînement du logement inférieur (22) ; et l'ensemble réservoir (14) peut être relié au logement inférieur (22) de sorte que le rotor centrifuge est entraîné en rotation par l'arbre de rotor par l'intermédiaire du pivot chemisé (34).


     
    2. Système de centrifugation selon la revendication 1, dans lequel l'entraînement est un entraînement pneumatique ou électrique.
     
    3. Système de centrifugation selon la revendication 1 ou la revendication 2, comprenant en outre une protection inférieure (42) fixée à la protection supérieure (32) avec le pivot chemisé (34) positionné en rotation entre les deux sans contact avec les protections supérieure (32) ou inférieure (42).
     
    4. Système de centrifugation selon la revendication 3, dans lequel la protection inférieure (42) comprend un canal capillaire (44) défini sur une surface supérieure (46), de préférence le canal capillaire (44) s'écartant en pente de l'ouverture de rotor (26).
     
    5. Système de centrifugation selon la revendication 3 ou la revendication 4, dans lequel la surface supérieure (54) du pivot chemisé (34) a une dimension extérieure qui est plus grande qu'une dimension intérieure d'une ouverture dans le guide inférieur (42).
     
    6. Système de centrifugation selon l'une quelconque des revendications 1 à 5, dans lequel le pivot chemisé (34) forme un point d'usure à une extrémité de l'arbre de rotor de l'entraînement.
     
    7. Système de centrifugation selon l'une quelconque des revendications 1 à 6, dans lequel le pivot chemisé (34) est reçu de façon amovible dans l'ensemble d'étanchéité sans contact (30) de sorte que le pivot chemisé (34) peut être remplacé.
     
    8. Système de centrifugation selon l'une quelconque des revendications 1 à 7, comprenant en outre un ou plusieurs éléments sur des surfaces d'étanchéité de la protection supérieure (32) et/ou du pivot chemisé (34), les un ou plusieurs éléments formant des vortex fluides dans l'ensemble d'étanchéité sans contact (30) suffisants pour atténuer une fuite du fluide du logement supérieur (20) à travers l'ouverture de rotor (26) dans l'entraînement dans le logement inférieur (22).
     
    9. Système de centrifugation selon l'une quelconque des revendications 1 à 8, comprenant en outre une source de pression (64) procurant un écoulement de gaz (40) entre une surface inférieure (56) de la protection supérieure (32) et une surface supérieure (54) du pivot chemisé (34), l'écoulement de gaz (40) ayant une direction opposée à une direction de fuite de fluide à travers l'ouverture de rotor (26).
     
    10. Système de centrifugation selon la revendication 9, dans lequel une source de pression (64) est suffisante pour retirer la chaleur de l'entraînement.
     
    11. Système de centrifugation selon la revendication 9 ou la revendication 10, dans lequel la source de pression (64) est une source de pression positive ou négative.
     
    12. Système de centrifugation selon l'une quelconque des revendications 9 à 11, dans lequel l'écoulement de gaz (40) est suffisant pour vaincre tout vortex et/ou différentiel de pression généré par la rotation du pivot chemisé (34).
     
    13. Système de centrifugation selon l'une quelconque des revendications 1 à 12, dans lequel la plaque d'appui (24) s'écarte en pente de l'ouverture de rotor (26) de sorte que le fluide capté par et sortant de l'ensemble d'étanchéité sans contact (30) est dirigé vers une périphérie extérieure (60).
     
    14. Système de centrifugation selon l'une quelconque des revendications 1 à 13, dans lequel la plaque d'appui (24) a un orifice de sortie (62) à une périphérie extérieure (60) à travers lequel un fluide peut être évacué de l'ensemble d'entraînement (16).
     
    15. Système de centrifugation selon la revendication 14, comprenant en outre une pompe d'évacuation fournissant un écoulement de gaz entre une surface inférieure (56) de la protection supérieure (32) et une surface supérieure (54) du pivot chemisé (34), l'écoulement de gaz ayant une direction opposée à une direction de fuite de fluide à travers l'ouverture de rotor (26), et la pompe d'évacuation évacuant un fluide de l'orifice de sortie (62) à la périphérie extérieure (60).
     




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    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description