EP0584277B1

EP0584277B1 - Centrifuge tube adapter

Info

Publication number: EP0584277B1
Application number: EP92913835A
Authority: EP
Inventors: William Andrew Romanuaskas; Thomas Edward Sheeran, Jr.
Original assignee: Sorvall Products LP
Current assignee: Sorvall Products LP
Priority date: 1991-05-06
Filing date: 1992-05-06
Publication date: 1998-01-28
Anticipated expiration: 2012-05-06
Also published as: EP0584277A1; CA2102320A1; DE69224289T2; WO1992019382A1; DE69224289D1; EP0584277A4; JP2777283B2; JPH06511187A

Description

The present invention relates to an adapter for holding a centrifuge tube in a centrifuge rotor cavity, and in particular, to an adapter having two segments, the segments being in some cases joined by a hinge, the hinge axis extending perpendicular to the axis of the adapter.

In the operation of a centrifuge it is important that the size and shape of the tube in which a liquid sample is carried closely conforms to the size and shape of the cavity in the centrifuge rotor in which the tube is received. During centrifugation the centrifugal force exerted on the tube itself and the liquid therein acts to deform the centrifuge tube. A centrifuge tube which does not closely conform to the rotor cavity may thus be deformed to the point of rupture. Even if the tube does not rupture the deformation may make the tube difficult to remove from the rotor cavity. Moreover, even if the deformed tube is removable from the rotor, the return of the tube to its undeformed shape may agitate the contents of the tube to an extent that destroys the sample separation.

When the shape and size of a centrifuge tube does not closely conform to the shape and size of the rotor cavity in which it is to be disposed a device known as a tube adapter is usually employed. The tube adapter has an interior cavity having a shape and size which closely conforms to the shape and size of the centrifuge tube being adapted. The exterior shape and size of the adapter closely conforms to the shape and size of the rotor cavity in which the tube is to be used. The adapter serves to support a tube within the cavity in which it is received and thus serves to prevent deformation of the tube during centrifugation.

Exemplary of an adapter formed of a single unitary member is the device disclosed in United States Patent 4,304,356 (Chulay et al.). This adapter supports only the neck region of the centrifuge tube and is fabricated of a material having a lower density than the liquid being carried therein to prevent bottoming of the adapter in the rotor cavity in the event of tube rupture.

Exemplary of an adapter formed of two piece construction is the device shown in United States Patent 3,674,197 (Mitchell et al.), assigned to the assignee hereof. This adapter comprises two discrete segments, each of which has an indentation therein. When joined the indentations form a recess for receiving a collapsible bag during centrifugation. The adapter disclosed in this patent includes aperture(s) through which tubes from the bag exit the adapter. Thus, the possibility exists that the bag may extrude through these apertures if the adapter were to undergo centrifugation in a vertical angle rotor.

An adapter arrangement formed of two discrete adapter segments and useful to support the capped end of a centrifuge tube is available as part of the Nalgene Ultra-Lok Tube System sold by Fisher Scientific Incorporated.

United States Patent 4,692,137 (Anthony) discloses a tube adapter having two segments which are hinged along the lateral edges of the segments. The hinge axes align in parallel relationship to the axis of the cavity in which the adapter is received. The disposition of hinges along the lateral edges of the segments is believed disadvantageous in that such a disposition may interfere with the insertion or removal of the adapter into or from the rotor cavity.

United States Patent 3,998,383 (Romanauskas et al.) and United States Patent 4,015,775 (Rohde), disclose centrifuge rotors of the vertical angle type. In such a rotor the axis of the rotor cavities is substantially parallel to the axis of rotation. When using a vertical angle rotor it is necessary that a cap be provided at the mouth of each cavity to impose a vertical restraining force on the tube disposed in the cavity. Even though the tube may be disposed in an adapter received within the cavity, without such a capping arrangement the possibility exists that the pressure of the liquid during centrifugation may rupture the tube. United States Patent 3,998,383 (Romanauskas et al.) exemplifies a typical capping arrangement for a vertical angle rotor.

It is an object of the present invention to improve the performance of an adapter for centrifuge tubes so that the adapter will maintain complete containment of the tube during centrifugation.

This object is solved, according to the invention, with the features of claim 1.

The present invention relates to an adapter for supporting a closed centrifuge tube in which at least one of the adapter segments has an effective weight sufficient to balance forces created by the pressure of a liquid carried in the tube under centrifugation that act transversely to the central axis. In use, with the adapter inserted into a cavity of a rotor, the one segment is disposed closer to the axis of rotation so that the mating surfaces of the adapter segments lie in a plane that is perpendicular to a radius of the rotor extending through the cavity. In such a disposition the weight of the one segment while under centrifugation is sufficient to maintain the mating surfaces of the adapter segments in contacting relationship with each other. Suitable keying may be provided to identify the one segment having the predetermined effective weight.

The invention will be more fully understood from the following detailed description thereof, taken in connection with the accompanying drawings, in which:

Figure 1 is a perspective view of an adapter used to support a closed tube within the cavity of a vertical angle rotor;

Figure 2A is a side sectional view of an adapter of Figure 1 in use and supporting a centrifuge tube over its entire axial length in a vertical angle centrifuge rotor cavity, while Figures 2B and 2C are, respectively, sectional views of the adapter as shown in Figure 2A taken along section lines 11B-11B and 11C-11C; and

Figure 3A is a perspective view of a modification of the adapter shown in Figures 1 and 2 with the inboard adapter segment having a keying configuration thereon, while Figure 3B is a side sectional view of the adapter of Figure 3A with the adapter segments joined together;

Figure 4 is a perspective view of another modification of the adapter shown in Figures 1 and 2;

Figure 5 is an enlarged view of a portion of the perspective view of Figure 4 illustrating a hinge arrangement useful with the modified adaptor shown therein;

Figure 6 is an enlarged view of the inboard segment of the modified adaptor shown in Figure 4 taken along view lines 15-15 therein;

Figure 7 is a side sectional view of an adapter of Figure 1 in use and supporting a centrifuge tube over its entire axial length in a vertical angle centrifuge rotor cavity.

An adapter may be fabricated from any suitable material so long as the resulting adapter has sufficient strength (as that term is defined herein). The material of choice must exhibit other desirable properties, such as appropriate ultimate strength, appropriate modulus of elasticity, suitable chemical compatibility with any liquid sample being centrifuged and ability to withstand autoclaving. Suitable plastic materials include polypropylene, polyamide, acetal, polyphenylene oxide, polyvinyl choloride, polycarbonate or polyethylene. Other plastic or metallic materials (either homogeneous (neat) or fiber reinforced) with similar or better mechanical and chemical properties for the application under consideration may also be used. The adapter may be formed in any convenient manner consistent with the material selected, such as molding, machining, casting or forging.

In order to support a tube T in a vertical angle rotor without the assistance of the restraining force provided by a capping mechanism, the adapter must exhibit sufficient strength to absorb the forces imposed on the tube T by the pressure of the liquid therein. Thus, as the term is used herein, "sufficient strength" means that the adapter must be able to withstand the forces imposed on it during centrifugation without failing or deforming to the extent that the tube carried therein ruptures.

Whether a given adapter is of sufficient strength can be determined from various readily ascertainable operating parameters of the vertical angle rotor in which the adapter is to be used and the application to which the adapter is to be put. These parameters are the specific weight of the liquid sample within the tube received by adapter, the radius R_i which represents the minimum distance to the sample from the axis A of rotation (Figure 2A), the diameter D_o (Figure 2A) of the rotor cavity, the thickness of the adapter segment, the inside diameter of the tube, and the speed of rotation of the vertical angle rotor.

The pressure at any location across the diameter of the tube in which the liquid sample is disposed is P = ω2 2g α ( Ro 2 - Ri 2) where

P is the pressure in Newton per meter² (psi),

ω is the rotational velocity of the rotor (radians per second),

g is acceleration due to gravity in meter per second² (inches per second²),

α is the specific weight of the sample in Newton per meter³ (Lb per inch³),

R_o is the distance to the point of interest x where the pressure value is desired from the center of rotation in meters (inches), and

R_i is the minimum distance to the sample from the axis A of rotation in meters (inches).

The total vertical force F_V that the adapter must withstand is then found by integrating this pressure function over the circular cross sectional area of the inside of the tube.

Knowing the adapter dimensions and the force F_V, the average stress in the wall of the adapter can be determined in accordance with the relationship: s = FV (π/4)(Do 2-Di 2) where

s is the stress in Newton per meter² (psi),

F_V is the force in Newton (Lbf)

D_o is the diameter of the rotor cavity, and

D_i is the inside diameter of the adapter when operating at speed, which equals the diameter of the rotor cavity minus the thickness of each of the segments of the adapter.

Based on the identity of the material used in the given adapter, the modulus of elasticity of that material may be readily obtained. An estimation of the vertical deformation of the adapter may be found by multiplying the initial length of the adapter by the average stress divided by the modulus of elasticity of the adapter material. If the average stress calculated in Equation (2) is less than the ultimate strength of the adapter material, and the predicted deformation is less than the deformation that will cause first leakage in the tube carried within the adapter, then the given adapter is to be construed to have sufficient strength for at least one operating cycle. The determination of sufficient strength as set forth above under operating conditions will verify both the analysis and the conclusion of the sufficiency of strength of the adapter.

It should be understood that it is within the contemplation of this invention to use an adapter in accordance herewith to support a tube or a predetermined portion thereof within a swinging bucket, thereby making the use of the adapter amenable for use in the environment of a swinging bucket rotor.

The adapter may be designed and fabricated such that, under centrifugation, the body force of one adapter segment is sufficient to balance the force created by the pressure of a liquid carried in the tube under centrifugation that acts transversely to the central axis. As will be developed, when in use the preferred form of such an adapter must be disposed within a cavity of a rotor in an orientation such that the mating surfaces of the adapter segments lie in a plane that is substantially perpendicular to a radius of the rotor extending through the cavity. In such an orientation the line of action of closure of the preferred form of such an adapter aligns with a radial line extending from the axis of rotation of the rotor to the center of the cavity in which the adapter is disposed.

Figure 1 illustrates a preferred arrangement of a split adapter 10⁴ for use in a vertical angle rotor. Structurally, the adapter 10⁴ includes a first adapter segment 12⁴ and a second adapter segment 14⁴. Each segment 12⁴, 14⁴ has an exterior surface 16⁴ and a mating surface 18⁴ thereon. The exterior surface 16⁴ of each segment 12⁴, 14⁴ is defined by a generally cylindrical lateral surface portion 20⁴ and a planar upper surface portion 22⁴. The exterior surface 16⁴ of each segment 12⁴, 14⁴ is sized and shaped for close fitting receipt within the cavity 40^V of a vertical angle rotor 42^V (Figures 2A through 2C).

Each segment 12⁴, 14⁴ is provided with an indentation 28⁴ in the mating surface 18⁴ thereof. The indentation 28⁴ in each segment 12⁴, 14⁴ is shaped so that when the segments 12⁴ and 14⁴ are joined along their mating surfaces 18⁴ the indentations 28⁴ cooperate to define a recess 30⁴ able to totally surround a centrifuge tube T disposed therein. The adapter 10⁴ has a central axis 10⁴A extending therethrough (Figure 2A). As will be discussed later, the recess 30⁴ may be inclined with respect to the central axis 10⁴A and remain within the contemplation of this invention.

The mating surfaces 18⁴ of the segments 12⁴, 14⁴ may be angled with respect to a reference plane. Alternatively or additionally, it should be noted that the adapter 10⁴ may be provided with a hinge on the upper surface 22⁴ of the segments. If a hinge is provided, the pivotal axis of the hinge extends perpendicular to the axis of the adapter. The hinge may take the form of a live hinge or a coined hinge.

At least one of the segments of the adapter 10⁴ must have a predetermined effective weight under centrifugation that is sufficient to prevent separation of the adapter segments. The effective weight of the adapter segment is defined as the weight of the segment at sea level multiplied by the g (gravity) force imposed on the segment when the same is rotated at a predetermined operating speed with the center of mass of the segment lying a predetermined radial distance from an axis of rotation.

At least one, but preferably, both of the segments 12⁴, 14⁴ has at least one, but preferably, a pair of resilient extensions 58⁴, 60⁴, respectively, thereon. In the preferred case the resilient extensions 58⁴, 60⁴ are flexibly mounted, as by hinging, to the outside surface 16⁴ of the segment along a line of bending 62⁴. The resilient extensions 58⁴, 60⁴ are biased to flare outwardly from the adapter segment, and are bendable along the line of bending 62⁴ to close inwardly toward the lateral surface portion 20⁴ of the outside surface 16⁴ of the segment to which they are attached. In the closed position the resilient extensions 58⁴, 60⁴ are in contact with the lateral surface portion 20⁴ of the outside surface 16⁴ of the segment to which they are attached. The lower end of each extension is tapered, as at 64⁴. It should be noted that when the adapter segments 12⁴, 14⁴ are mated the edges of resilient extensions 58⁴, 60⁴ are circumferentially spaced a slight distance apart, thereby to provide sufficient clearance to accommodate the flexing motion of the resilient extensions 58⁴, 60⁴ during insertion into the rotor cavity. As will become clearer herein each extension 58⁴, 60⁴ serves to frictionally interact with the boundaries of a rotor cavity 40^V (Figure 2A through 2C) to prevent rotation of the adapter 10⁴ about its axis 10⁴A with respect to the body of the rotor 42^V thereby to maintain the adapter 10⁴ in a predetermined angular orientation within the cavity during operation of the rotor.

Figures 2A through 2C illustrate the adapter 10⁴ of Figure 1 in use in a cavity 40^V of a vertical angle centrifuge rotor 42^V. Sectioning of the adapter has been omitted from Figure 2C for clarity of illustration. When disposed in the rotor 42^V the segment (for example, the segment 12⁴) which lies closer to the axis of rotation A of the rotor is termed the "inboard" segment. The other segment 14⁴ which lies farther from the axis of rotation 10A is termed the "outboard" segment. The inboard segment 12⁴ must have an effective weight sufficient to balance the force F_T created by the pressure of a liquid carried in the tube under centrifugation that acts transversely to the central axis 10⁴A of the adapter 10⁴. Such an arrangement precludes separation of the adapter segments 12⁴, 14⁴ during centrifugation. When properly positioned in the cavity 40^V of the rotor 42^V the mating surfaces 18⁴ of the adapter segments 12⁴, 14⁴ are disposed so as to lie in a plane 68 (Figure 2A) that is substantially perpendicular to a radius of the rotor 42^V extending through the cavity 40^V. The plane 68 is the plane of Figure 2B.

It should be noted that in some instances the recess 30⁴ may be arranged within the adapter 10⁴ such that an axis extending centrally through the recess 30⁴ of the adapter 10⁴ is offset radially with respect to the axis 10⁴A of the adapter 10⁴. In such an arrangement the recess 30⁴ is not concentric with the generally cylindrical lateral surface portion 20⁴ of the adapter 10⁴. If so offset it is preferred that the recess 30⁴ be displaced radially outwardly with respect to the axis 10⁴A of the adapter 10⁴. Such an arrangement may be utilized to increase the effective weight of the inboard segment 12⁴ and/or to dispose the sample to higher g-forces resulting from the increased radial distance to the sample.

Whether the inboard adapter segment 12⁴ has an effective weight sufficient for the purpose of containing the transverse force F_T, can be determined from consideration of the identical operating parameters as previously developed and described in connection with the "sufficient strength" determination for accommodation of the vertical force F_V.

As earlier noted the pressure P across the diameter of the tube is defined by Equation (1). The value of the pressure P ranges from zero at the inboard edge of the tube to a maximum value at the farthest radial location of the liquid sample from the axis of rotation of the rotor. The inboard segment 12⁴ of the adapter 10⁴ is subjected to a radially inwardly directed force F_T that results from liquid pressure in the inboard half of the tube. The magnitude of this radially inwardly directed force F_T is determined by integrating the component of the pressure function defined by Equation (1) that is parallel to a radial line through the center of mass of the inboard segment 12⁴ over the surface area of the indentation 28⁴ of the adapter segment 12⁴. So long as the effective weight of the inboard segment 12⁴ is equal to or greater than the force F_T due to liquid pressure, then centrifugal force effects acting on the inboard segment 12⁴ cause the mating surfaces 18⁴ of the adapter segments 12⁴, 14⁴ to remain in contacting relationship. The adapter 10⁴ will thus maintain complete containment of the tube during operation of the rotor.

The adapter 10⁴ may be fabricated from any suitable material so long as the resulting adapter segment 12⁴ has sufficient effective weight (as that term is defined herein) and exhibits suitable chemical compatibility with any liquid sample being centrifuged. It should preferably have the ability to withstand sterilization, as by autoclaving. Suitable plastic materials include polypropylene, polyamide, acetal, polyphenylene oxide, polyvinyl choloride, polycarbonate or polyethylene. Other plastic or metallic materials (either homogeneous (neat) or fiber reinforced) with similar or better mechanical and chemical properties for the application under consideration may also be used. The adapter may be formed in any convenient manner consistent with the material selected, such as molding, machining, casting or forging.

It should be understood that both the segments 12⁴, 14⁴ may be substantially identical in weight or they may be substantially different in weight, so long as the inboard adapter segment has the requisite effective weight to completely contain the tube T during operation of the rotor.

It is preferred that the adapter 10⁴ also be fabricated of a material that has sufficient strength to withstand the vertical force F_V due to liquid pressure under centrifugation. Of course, if the adapter 10⁴ is not able to withstand the vertical force F_V, then a separate capping arrangement on the rotor is required.

By providing the inboard segment 12⁴ having a suitable effective weight the mating surfaces on the inboard and outboard segments remain in contact during operation of the rotor and no gap therebetween may form. The tube T is thus completely contained within the conjoined adapter segments during operation of the rotor, and the possibility of tube failure due to extrusion into a gap is precluded. The present invention carries the additional benefit of minimizing circumferential stress in the tube caused by the pressure of the liquid, therefore further reducing the possibility of tube failure. Since the effective weight of the inboard segment of the adapter is at least as great as the transverse force due to pressure F_T, the inboard segment limits expansion of tube. Greater tube reliability over a greater range of tube, adapter and cavity tolerances is thus produced.

As previously mentioned, the adapter 10⁴ must be disposed in the cavity 40^V of the rotor 42^V in an orientation which substantially aligns the line of action 48 of closure of the adapter segments 12⁴, 14⁴ with a radial line extending from the axis of rotation of the rotor to the center of the cavity 40^V in which the adapter is disposed and which places the mating surfaces 18⁴ of the adapter segments 12⁴, 14⁴ in the plane 68 (Figure 2A) that is perpendicular to the radius extending through the cavity 40^V. To meet this need, the segments 12⁴, 14⁴ may be keyed in a fashion to be described.

If both segments 12⁴, 14⁴ have the requisite effective weight sufficient to ensure complete containment of the tube in the adapter recess, then either segment may assume the position of the inboard segment. Thus, the adapter may be inserted into the cavity in either of two different orientations and the desired performance will occur.

The keying can be implemented by providing any suitable distinctive physical feature on the adapter, such as a visually distinctive marking or a distinctive shape.

Should only one segment 12⁴ exhibit the requisite effective weight then a form of keying is necessary which both: (1) identifies that segment as the inboard segment; and (2) aligns the mating surfaces 18⁴ of the adapter segments 12⁴, 14⁴ in the plane 68.

An embodiment of the adapter 10⁴ in which only one segment 12⁴ exhibits the requisite effective weight is illustrated in Figures 3A and 3B. In this modification the inboard adapter segment 12⁴ has a distinctive configuration imparted thereto in the form of the flat surfaces 68⁴ provided on the exterior surface 16⁴ of the segment 12⁴. The cavity 40^V into which the adapter 10⁴ of Figure 3 is insertable is correspondingly shaped, thus to ensures that the adapter 10⁴ is properly received into the rotor 42^V.

In addition, a portion of the upper surface 22⁴ of the inboard segment 12⁴ is removed to define a channel 70⁴ therein. The mating surfaces 18⁴ on the inboard segment 12⁴ are flush with the boundaries of the channel 70⁴. The upper surface 22⁴ of the outboard segment 14⁴ is provided with a projecting flange 72⁴ that is shaped in correspondence to the channel 70⁴. In addition, the mating surfaces 18⁴ on the outboard segment 14⁴ are arranged to slidably engage the corresponding mating surfaces 18⁴ on the inboard segment 12⁴. The undersurface of the flange 72⁴ has a pocket 76⁴ therein that accepts the upper capped end of the tube T.

This structure defines a compact, cartridge-like adapter 10⁴ for the tube T. When the segments are separated, the tube T is retained in the outboard segment 14⁴ with the capped end of the tube T received in the pocket 76⁴ therein. This disposition is believed to facilitate handling of the tube T.

As briefly noted earlier, it may be desirable in some instances to orient the indentations within each adapter segment such that a central axis through the recess formed when the segments are joined is inclined to the axis of the adapter. Such an adapter may be useful in converting a vertical angle rotor to a rotor having a "near vertical" cavity orientation. The mating surfaces of the segments in such a case will lie in a plane that contains the axis of the recess, said plane also being inclined with respect to the axis of the adapter. These mating surfaces of such an adapter need not, therefore, align with the plane perpendicular to a radius extending from the axis of rotation of the rotor through the center of the cavity, as shown in Figures 1 through 3.

Figures 4, 5, 6 and 7 illustrate another embodiment of a compact, cartridge-like adapter 10⁴ similar to that shown in Figures 3A and 3B. The adaptor 10⁴ includes adapter segments 12⁴, 14⁴, each of which has an exterior surface 16⁴ and a mating surface 18⁴ thereon. When the segments 12⁴, 14⁴ of the adaptor 10⁴ are conjoined the exterior surface 16⁴ has a cylindrical configuration similar to the adaptor of Figure 2C (without the resilient extensions 58⁴ and 60⁴) and is thus insertable in a correspondingly shaped cylindrical rotor cavity 40^V (Figure 7).

Similar to the case shown in Figures 3A and 3B, the mating surfaces 18⁴ include those planar surfaces of the adapter segments 12⁴, 14⁴ that align in the plane 68 (perpendicular to the radius of the rotor 42⁴) when the adapter is received within the rotor, as well as planar lateral surfaces that extend generally perpendicular thereto. The former are indicated in the Figures by the

character

18⁴ and 18^4' respectively. The mating surface 18⁴ in each segment is provided with an indentation 28⁴ that cooperate to define a recess 30⁴ sized to accept a centrifuge tube T therein. As is also the case with the arrangement of Figures 3A, 3B, in the adapter 10⁴ of Figures 4 through 7 only one segment, e. g., the inboard segment 12⁴, exhibits the requisite effective weight to insure that the mating surfaces 18⁴ on the inboard segment 12⁴ and the outboard segment 14⁴ remain in contact during operation of the rotor so that no gap therebetween may form.

In the arrangement of Figures 4 through 7 a portion of the upper surface 22⁴ of the outboard segment 14⁴ is removed to define the channel 70⁴ therein. The upper surface 22⁴ of the inboard segment 12⁴ is provided with the projecting flange 72⁴ that is shaped in correspondence to the channel 70⁴. The lateral portions 18^4' of the mating surfaces 18⁴ on the inboard segment 12⁴ are arranged to slidably engage the corresponding lateral portions 18^4' of the mating surfaces 18^4' on the outboard segment 14⁴. The undersurface of the flange 72⁴ may have a pocket 76⁴ therein that accepts the upper capped end of the tube T. Thus, when the segments 12⁴, 14⁴ are separated a tube T is retained in the inboard segment 12⁴.

The projecting flange 72⁴ on the upper surface 22⁴ of the inboard segment 12⁴ has gripping serrations 80⁴ provided thereon. These gripping serrations 80⁴ facilitate manipulations of the segments. In addition the presence of the serrations 80⁴ serves as a visual indicator key which both identifies the inboard segment and aligns the mating surfaces 18⁴ of the adapter segments 12⁴, 14⁴ in the plane 68. As perhaps best seen in Figure 6 a portion 82⁴ of the flange 72⁴ also projects forwardly thereby to overhang exterior surface 16⁴ on the inboard segment 12⁴. As is seen in Figure 7 when the adaptor 10⁴ is received within the cavity 40^V of the vertical rotor 42^V the forwardly projecting portion 82⁴ abuts against a shelf 45^V that is formed about the mouth of the cavity on the inboard side thereof. It should be understood by those skilled in the art that an adapter as shown in Figures 1 through 7 can also be used in rotors other than vertical rotors.

As briefly noted earlier, the segments 12⁴, 14⁴ may be hinged. Since the serrated flange 72⁴ is located at the upper end of the cartridge adaptor 10⁴ a more convenient form of hinge arrangement 26⁴ is shown in Figures 4 and 5. The hinge arrangement 26⁴ includes a pair of stub-like axles 86⁴ disposed opposed lateral surface portions 18⁴ of the mating surface 18⁴ of the inboard segment 12⁴. The hinge arrangement 26⁴ further includes a pair of trunnion recesses 88⁴ provided on the opposed confronting lateral surface portions 18^4' of the mating surface 18⁴ of the outboard segment 14⁴. The stub-like axles 86⁴ on the inboard segment 12⁴ snappingly engage into the trunnion recesses 88⁴ on the outboard segment 14⁴. The axis 26A⁴ of the hinge 26⁴ is perpendicular to the axis of the adapter 10⁴ and supports the relative pivotal movement, about the hinge axis 26A⁴ of the segment 12⁴, 14⁴ with respect to the other from an open to a mated position.

The adapter 10⁴ of Figures 4-7 may be fabricated of the same material as used for the adapter 10⁴ of Figures 3A, 3B.

In connection with the arrangement of Figures 3A, 3B as well as Figures 4-7 it should be understood that in some instances it may be desirable to orient the indentations within each adapter segment such that a central axis through the recess formed when the segments are joined is inclined to the axis of the adapter. Such an adapter may be useful in converting a vertical angle rotor to a rotor having a "near vertical" cavity orientation. The mating surfaces of the segments in such a case will lie in a plane that contains the axis of the recess, said plane also being inclined with respect to the axis of the adapter. These mating surfaces of such an adapter need not, therefore, align with the plane perpendicular to a radius extending from the axis of rotation of the rotor through the center of the cavity.

Claims

Use of an adapter (10⁴) for supporting a closed centrifuge tube (T) within a cavity (40^V) of a centrifuge rotor (42^V), the adapter (10⁴) comprising:

a first, inboard, adapter segment (12⁴) and a second, outboard, adapter segment (14⁴), each segment (12⁴,14⁴) having an exterior surface (16⁴) and a mating surface (18⁴) thereon, each segment (12⁴,14⁴) having an indentation (28⁴) in the mating surface (18⁴) thereof, the indentation (28⁴) in each segment (12⁴,14⁴) being shaped such that when the segments (12⁴,14⁴) are joined along their mating surfaces (18⁴,18⁴) the indentations (28⁴,28⁴) cooperate to define a recess (30⁴) able to totally surround a centrifuge tube (T) disposed therein, the adapter (10⁴) having a central axis (10⁴A) extending therethrough,
characterized by

the use of a first, inboard, segment (12⁴) having an effective weight sufficient to balance forces created by the pressure of a liquid carried in the tube (T) under centrifugation that act transversely to the central axis (10⁴A),

so that, in use with the adapter (10⁴) inserted into a cavity (40^V) of a rotor (42^V) with the mating surfaces (18⁴,18⁴) of the adapter segments (12⁴,14⁴) being in contacting relationship with each other, the effective weight of the inboard segment (12⁴) while under centrifugation is sufficient to maintain the mating surfaces (18⁴,18⁴) of the adapter segments (12⁴,14⁴) in such contacting relationship.
The use of claim 1 wherein the outboard segment (14⁴) has a predetermined effective weight, and
wherein the effective weight of the inboard segment (12⁴) is different from the effective weight of the outboard segment (14⁴).
The use of claim 2 wherein the effective weight of the inboard segment (12⁴) is greater than the effective weight of the outboard segment (14⁴).
The use of claim 1 wherein the outboard segment (14⁴) has a predetermined effective weight, and wherein the effective weight of the inboard segment (12⁴) is the same as the effective weight of the outboard segment (14⁴).
The use of claim 1 or 2 wherein one of the segments (12⁴,14⁴) has a distinctive feature thereon.
The use of claim 5 wherein the distinctive feature is a visual feature.
The use of claim 5 wherein the distinctive feature is the shape of the segment.
The use of claim 5 wherein the distinctive feature is on the inboard segment (12⁴).
The use of claim 8 wherein the distinctive feature is a visual marking.
The use of claim 8 wherein the inboard segment (12⁴) has a predetermined shape, and wherein the distinctive feature is the shape of the inboard segment.
The use of one of claims 1-10 wherein the cavity (40^V) of the rotor (42^V) is circular and wherein each of the segments (12⁴,14⁴) has an exterior surface (16⁴) thereon, at least one of the segments (12⁴) has at least a first resilient extension (58⁴) thereon, the resilient extension (58⁴) being biased to flare outwardly from the adapter segment (12⁴), the resilient extension (58⁴) being bendable with respect to the adapter segment (12⁴) from the flared position to a second position in which the extension (58⁴) contacts against the exterior surface (16⁴) of the segment (12⁴) on which it is disposed, whereby,
when the adapter (10⁴) is disposed in a rotor (42^V), the extension (58⁴) frictionally interacts with the boundaries of a rotor cavity (40^V) to prevent rotation of the adapter (10⁴) about its axis (10⁴A) with respect to the body of the rotor (42^V), thereby to maintain the adapter (10⁴) in a predetermined angular orientation within the cavity (40^V) during operation of the rotor (42^V).
The use of claim 11 wherein the extension (58⁴,60⁴) is hinged to the segment (12⁴,14⁴) along a line of bending (62⁴) disposed on the exterior surface (16⁴) of the segment (12⁴,14⁴).
The use of claim 12 wherein the extension (58⁴,60⁴) has a tapered portion (64⁴) thereon.
The use of one of claims 1-13 wherein the inboard segment (12⁴) has an exterior surface (16⁴) thereon, the exterior surface (16⁴) having at least one planar keying region (68⁴) defined thereon.
The use of claim 14 wherein both the inboard segment (12⁴) and the outboard segment (14⁴) have an upper surface (22⁴) thereon, the inboard segment (12⁴) having a channel (70⁴) formed through the upper surface (12⁴) thereon, the outboard segment (14⁴) having a flange (72⁴) shaped in correspondence to the channel (70⁴) disposed on the upper surface (22⁴) thereof, the flange (72⁴) having a pocket (76⁴) formed therein, the pocket (76⁴) being sized to receive the end of a tube (T) received within the adapter (10⁴).
The use of one of claims 1-15 wherein the centrifuge rotor (42^V) is a vertical angle rotor, and wherein the adapter segments (12⁴,14⁴) are fabricated of a material that has sufficient strength to withstand the vertical forces created by the pressure of a liquid under centrifugation.
The use of claim 1 or 16 further comprising at least one hinge (26⁴) connecting the segments (12⁴,14⁴) and supporting the relative pivotal movement, about a hinge axis (26⁴A), of at least one segment (12⁴) with respect to the other (14⁴) from an open to a mated position, the hinge axis (26⁴A) extending perpendicular to the axis of the adapter (10⁴A).
The use of claim 17 wherein the hinge (26⁴) comprises a pair of axles (86⁴) formed at the lower end of one segment (12⁴) and a pair of trunnion recesses (88⁴) formed at a corresponding location on the other segment (14⁴).
The use of claim 2 wherein the effective weight of the outboard segment (14⁴) is greater than the effective weight of the inboard segment (12⁴).
The use of one of claims 1-19 wherein the inboard segment (12⁴) has a flange (72⁴) and the outboard segment (14⁴) has a channel (70⁴) therein sized to receive the flange (72⁴), the flange (72⁴) having serrations (80⁴) thereon.
The use of claim 20 wherein the flange (72⁴) on the inboard segment (12⁴) has an overhanging projection (82⁴) thereon adapted to seat against a shelf provided in a centrifuge rotor (42^V).