GB2617842A

GB2617842A - Apparatus for centrifuging

Info

Publication number: GB2617842A
Application number: GB2205735.0A
Authority: GB
Inventors: James Tinegate-Smith Benjamin; Jennings Honor; O'connor Joseph
Original assignee: Entia Ltd
Current assignee: Entia Ltd
Priority date: 2022-04-20
Filing date: 2022-04-20
Publication date: 2023-10-25
Also published as: GB202205735D0; WO2023203315A1

Abstract

A centrifuge comprising a rotor 12, which may be driven to rotate during a centrifuging process, the rotor having an axis of rotation and an outer edge, wherein: the rotor has an aperture (14, fig. 2) for receiving a sample holder (1, fig. 1), the aperture being formed in a first surface (13, fig. 3) of the rotor and being positioned between the axis of rotation and the outer edge, the aperture having an internal surface (26, fig. 3) on which the sample holder may be received; the aperture has an end wall 29 which faces generally towards the axis of rotation; and the rotor includes a lip 21, which overlies a part of the aperture in the region of the end wall, the lip being spaced apart from the internal surface and defining a region between the internal surface and an underside of the lip. The lip can hold a cuvette in place during rotation and so the centrifuge may not include a lid.

Description

Title: Apparatus for centrifuging.

Description of Invention

The present application relates to an apparatus for centrifuging.

When a sample of a liquid is to be analysed by centrifuging, it is common for the sample to be collected in the first instance using a relatively small, hand-held device such as a Guyette. The cuvette is then placed into a centrifuge for analysis.

In general, the centrifuge will include a disc-shaped component which may be driven to rotate rapidly about an axis. The disc contains an aperture which receives the cuvette, and in all or most examples when the cuvette is received in the aperture, a sample chamber of the cuvette is aligned or substantially aligned with a radial axis of the disc. Subsequent rotation of the disc causes separation of different phases or substances within the liquid sample, as is known in the art.

It is an object of the invention to provide an improved apparatus for centrifuging, in particular one which can be more easily operated by a non-specialist user, and more particularly a user who may have reduced or impaired sight and/or dexterity.

REPRESENTATIVE FEATURES

Representative features are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the text and/or drawings of the specification.

One aspect of the present application provides a centrifuge comprising a rotor, which may be driven to rotate during a centrifuging process, the rotor having an axis of rotation and an outer edge, wherein: the rotor has an aperture for receiving a sample holder, the aperture being formed in a first surface of the rotor and being positioned between the axis of rotation and the outer edge, the aperture having an internal surface on which the sample holder may be received; the aperture has an es generally towards the axis of rotation; and the rotor includes a lip, which overlies a part of the aperture in the region of the end wall, the lip being spaced apart from the internal surface and defining a region between the internal surface and an underside of the lip.

Advantageously, the aperture has an inner end, which lies closest to the axis of rotation, an outer end, which lies closest to the outer edge, and wherein the lip overlies a part of the aperture at or near the outer end Preferably, the rotor has a first surface, in which the aperture is formed, and wherein the internal surface is offset from the first surface of the rotor.

Conveniently, in the region of the lip, the lip is parallel or substantially parallel with the first surface of the rotor.

Advantageously, in the region of the lip, an upper surface of the lip is aligned or substantially aligned with the first surface of the rotor.

Preferably, the aperture does not pass all the way through a thickness of the rotor.

Conveniently, the first surface of the rotor is an upper surface thereof.

Advantageously, the rotor has a lower surface, the thickness of the rotor being defined between the upper and lower surfaces.

Preferably, the lip adjoins the end wall.

Conveniently, a deflecting surface is formed, extending between the end wall and the underside of the lip, the deflecting surface subtending an angle with both the end wall and the underside of the lip.

Advantageously, a deflecting surface is formed, extending between the end wall and the internal surface, the deflecting surface subtending an angle with both the end wall and the internal surface.

Preferably, in the region of the lip the aperture has a width, and the lip extends all or substantially all of the way across the width.

Conveniently, the length of the lip is at least 5% of the length of the aperture.

Advantageously, the centrifuge further comprises a housing, in which the rotor is mounted, and a drive arrangement to drive rotational motion of the rotor.

Preferably, the centrifuge does not have a cover which is placed directly over the aperture during a centrifuging process.

Another aspect of the present invention provides a centrifuging apparatus, comprising: a centrifuge according to any of the above; and a cuvette, wherein the 15 cuvette may be received in the aperture.

Conveniently, the cuvette may be placed into an initial position in the aperture by being advanced into the aperture in a direction which is substantially perpendicular to the axis of rotation of the rotor, so that the cuvette is received in regions of the aperture which are not the region between the internal surface and an underside of the lip.

Advantageously, from the initial position, the cuvette may be moved in a direction passing from the axis of rotation of the rotor towards the outer edge thereof, without being removed from the aperture, into a second position, in which a part of the cuvette is received in the region between the internal surface and an underside of the lip.

Preferably, when the cuvette is in the initial position, rotation of the rotor about the axis of rotation at a sufficient rate will drive the cuvette into the second position.

Conveniently, the aperture comprises one or more finger holes, comprising regions of the aperture which are not occupied by the cuvette when the cuvette is received in the aperture.

Advantageously, the finger holes comprise regions of the aperture which are not occupied by the cuvette in either the initial position or the second position.

Preferably, the aperture comprises two finger holes, which extend from the aperture from substantially opposite sides thereof.

Conveniently, the or each finger hole extends from the aperture in a direction which is generally perpendicular to a direction passing from the axis of rotation of the rotor to the outer edge thereof.

Advantageously, the cuvette has one or more projecting ridges, and the internal surface of the rotor has one or more corresponding grooves formed therein, and wherein, when the cuvette is placed in the first or second position, the one or more 15 grooves are received in the respective grooves.

Preferably, the cuvette may slide with respect to the internal surface from the first position to the second position, with the one or more grooves remaining in the respective grooves.

In order that the invention may be more readily understood embodiments therefore will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a first cuvette suitable for use with the invention; Figure 2 shows a rotor embodying the invention, suitable for use with the cuvette of figure 1; Figure 3 is a cut-away view of the rotor of figure 2; Figures 4 to 6 show the view of figure 3, during various stages of use of the rotor with the cuvette of figure 1; lOW a preferred feature of the cuvette; Figure 9 shows an alternative arrangement of the lip of the rotor of figure 2; Figure 10 shows a second cuvette suitable for use with the invention; Figure 11 shows a receiving aperture of a rotor embodying the invention, suitable for use with the cuvette of figure 10; and Figure 12 shows the cuvette of figure 10, in the receiving aperture of figure 11.

Turning firstly to figure 1, a cuvette 1 suitable for use with the present application is shown. For the avoidance of doubt, embodiments of the invention may work with many different and varied designs of cuvette, and the invention is not limited to use with a cuvette of the design shown in figure 1.

The cuvette 1 has a main body 2 which is generally flat and substantially planar. A front end 3 has a pointed apex portion 4, with the point of the apex comprising a tip 34 of the cuvette. A rear end 5 of the cuvette 1 has a generally flat rear edge 6.

The main body 2 has a generally flat upper surface 7, and an opposing bottom surface 8. Over the majority of the area of the main body 2, the top and bottom surfaces 7, 8 are generally parallel with each other, and separated by distance which corresponds to the depth of the main body 2.

In the examples shown the cuvette 1 has opposing side edges 32, 33, which are parallel or substantially parallel with each other. In this example the main body 2 of the cuvette 1 is generally rectangular, aside from the pointed apex portion 4. Where edges meet each other, the cuvette 1 has rounded corners, to increase ease of handling.

On opposite sides of the main body 2, close to the front end 3 of the cuvette 1, protrusions 9 extend upwardly and downwardly from the plane of the main body 2. In the embodiment shown, each protrusion 9 takes the form of a ridge, which 5 top or bottom surface 7, 8 and which is aligned or substantially aligned with a central longitudinal axis of the cuvette 1. The central longitudinal axis, in the example shown, passes along the length of the cuvette 1 from the front end 3 to the rear end 5, midway or approximately midway between the side edges 32, 33.

Each projection 9 has a shape which is generally semi-circular, when seen in the plane of the main body 2 of the cuvette 1. In the example shown the projections 9 which protrude from the top and bottom surfaces 7, 8 on each side of the main body 2 are aligned with each other, i.e. each protrusion 9 on the top surface 7 is directly opposite a corresponding protrusion on the bottom surface 8. This need not be the case, however.

In use, the tip 4 of the cuvette 1 is brought into contact with a sample of a liquid, for instance a drop of blood. The liquid is drawn into the cuvette 1, and in the first instance is received in a collection chamber. The collection chamber is not directly visible in figure 1, although a first window 10, positioned at or near the tip 4, allows liquid in the collection chamber to be seen easily by a user of the cuvette 1.

In preferred embodiments the majority of the exterior of the cuvette 1 has a textured or frosted finish, for ease of handling, with the first window 10 being transparent or substantially transparent.

Upon centrifugation, the liquid that has been received in the collection chamber is driven into an analysis chamber, which is elongate, and preferably has a constant width and depth along its length. Again, the analysis chamber is not directly visible in figure 1, although a second window 11 allows liquid in the analysis chamber to be seen by a user of the cuvette 1. The second window 11 is preferably elongate and generally aligned with the central longitudinal axis of the cuvette 1. As with the first window 10, the second window 11 is transparent or substantially transparent.

Turning to figure 2, a part of a disc 12 is shown. As will be described in more detail below, the disc 12 is a rotor of a centrifuge. The centrifuge will comprise (not shown), such as a housing in which the disc 12 is mounted, and a motor or other drive arrangement to drive rotational motion of the disc. The centrifuge also preferably comprises an analysis arrangement, to analyse or otherwise obtain data regarding a sample. The analysis arrangement may include, for instance, one or more light sources and one or more light sensors.

In use, the disc 12 will rotate around a central axis (not shown). For clarity, only one part of an edge of the disc 12 is shown.

An upper surface 13 of the disc 12 has a receiving aperture 14 formed therein. In preferred embodiments of the invention, the receiving aperture 14 does not pass all of the way through the thickness of the disc 12.

The receiving aperture 14 is adapted to receive the cuvette 1 shown in figure 1.

The shape of the receiving aperture 14 will now be described. The skilled reader will appreciate that some of the aspects of the shape are dictated by the shape of the cuvette 1. As discussed above, the invention is not limited to use of the cuvette shown in figure 1, and if a different shape and/or design of cuvette is used, the shape of the receiving aperture 14 will be correspondingly different.

An inner end 15 of the receiving aperture 14, which lies closest to the central axis of the disc 12, has a shape which corresponds at least approximately to the shape of the front end 3 of the cuvette 1. As can be seen in figure 2, the inner end 15 25 has a shape which tapers to a point 16.

As the receiving aperture 14 passes from the inner end 15 thereof towards an outer end 17, which lies furthest from the axis of rotation and closest to the outer edge 18 of the disc 12, the receiving aperture 14 has (aside from finger holes, which are discussed below) respective side edges 35, 36, defining a width 19 therebetween which is same or approximately the same as, or slightly greater than, the width of the main body 2 of the cuvette 1.

dly from the side edges 35, 36 of the receiving aperture 14, respective first and second finger holes 20 are formed. Each finger hole 20 takes the form of a region of the receiving aperture 14 which extends laterally outwardly, and in the example shown in figure 2 each finger hole 20 has an approximately semi-circular shape. In the example shown the finger holes are opposite one another, in that they are at the same or substantially the same distance from the axis of rotation of the disc 12.

Preferably, the two finger holes 20 are generally symmetrical, i.e. they are substantially mirror images of one another. However, this need not be the case.

At the outer end 17 of the receiving aperture 14, which lies furthest from the axis of rotation of the disc 12, an overhanging lip 21 is provided This is discussed in more detail below.

The parts of the receiving aperture 14 discussed above preferably have a substantially constant depth. The receiving aperture 14 has an upward-facing surface 26, which in the example shown is parallel or generally parallel with the upper surface 13 of the disc 12.

Towards the inner end 15 of the receiving aperture 14, a pair of indented grooves 22 is formed, one on each side of the receiving aperture 14. These grooves 22 have a width and depth such that one of the protrusions 9 of the cuvette 1 may be received in each groove 22. The depth of each groove 22 is preferably sufficient that a protrusion 9 may be fully received therein, so that the main body 2 of the cuvette 1 may lie flat against the upper surface 26 of the receiving aperture 14.

Each of the grooves 22 is longer than one of the protrusions 9. This means that, when a protrusion 9 is received in one of the grooves 22, the cuvette 1 may slide with respect to the disc 12 by at least some distance in a direction which is parallel with the grooves 22. The advantage of this will be discussed in more detail below.

In the example shown, an analysis aperture 47 is formed through the upward-facing surface 26 of the receiving aperture 14. The analysis aperture 47 is formed p the thickness of the disc 12. The analysis aperture 47 is preferably positioned so that, when the cuvette 1 is placed in the receiving aperture 14, the analysis aperture 47 is aligned or substantially aligned with the second window 11 of the cuvette 1. The presence of the analysis aperture 47 allows analysis of a liquid sample in the analysis chamber of the cuvette 1 from the lower side of the disc 12, as will be understood by a skilled reader.

Turning to figure 3, a cross-sectional view through the disc 12 is shown.

As can be seen in figure 3, the receiving aperture 14 does not (aside from the analysis aperture 47) pass all of the way through the depth of the disc 12, and extends only part of the way from the upper surface 13 to an opposing bottom surface 23 thereof.

The majority of the receiving aperture 14 is open, in that there is no obstruction between the upper surface 26 of the receiving aperture 14 and a region immediately above the upper surface 13 of the disc 2. However, as mentioned above, at the outer end 17 of the receiving aperture 14 there is an overhanging lip 21, which is spaced apart from the upper surface 26 and defines a space 24 between the lip 21 and the upper surface 26.

The underside 25 of the lip 21 is preferably parallel or substantially parallel with the upper surface 26 of the receiving aperture 14. When viewed from directly above the upper surface 13 of the disc 12, a region of the upper surface 26 at the outer end 17 of the receiving aperture 14 is obscured by the lip 21.

The distance between the underside 25 of the lip 21 and the upward-facing surface 26 of the receiving aperture 14 defines a depth which is at least as great as the thickness of the main body 2 of the cuvette 1.

The length of the receiving aperture 14 is preferably sufficient that the cuvette 1 may be placed directly into the receiving aperture 14, by being advanced into the receiving aperture 14 in a direction which is perpendicular with the plane of the disc 12. The distance between the inner end 16 of the receiving aperture 14, and the overhanging lip 21, is therefore at least as long as the total length of the cuvette 1.

As can be seen in figure 2, the lip 21 has a first length in the region of the centre of the receiving aperture 14, and a second greater length at the side edges 35, 36 of the receiving aperture 14. The free end 39 of the lip 21 preferably describes a curved shape towards the side edges 35, 36 as it transitions from the first length to the second length.

Use of the cuvette 1 and disc 12 will now be described. As discussed above, the cuvette 1 will be used to collect a sample of a liquid, which in preferred examples may be blood. A subject may use a lancet or other implement to pierce his/her skin, leading to the production of a drop of blood. The tip 34 of the cuvette 1 may be touched against the drop of blood, leading to a quantity of the blood being drawn into the receiving chamber of the cuvette 1.

The cuvette 1 is then placed into the receiving aperture 14 of the disc 12, with the tip 4 of the cuvette 1 generally aligned with the inner end 15 of the receiving aperture 14. The protrusions 9 on the underside of the cuvette 1 will be received in respective ones of the grooves 22 which are formed as part of the receiving aperture 14. In this configuration, each protrusion 9 will be received in (or near) the end of the respective groove 22 which is closest to the inner end 15 of the receiving aperture 14.

This situation is shown in figure 4.

At this stage, rotation of the disc 12 has not yet begun.

The skilled reader will appreciate that the finger holes 20 which are provided on either side of the receiving aperture 14 will increase the ease with which a user may place the cuvette 1 into the receiving aperture 14. As the user grips the cuvette 1, to place the cuvette 1 into the receiving aperture 14, the user is likely to grip the left and right side edges 32, 33 of the cuvette 1 between his/her thumb and forefinger. As the user places the cuvette 1 into the receiving aperture 14, presence of the finger holes 20 will allow the tips of the user's thumb and forefinger to be accommodated in the finger holes 20, thus making it more comfortable and straightforward to place the cuvette 1 into the receiving aperture 14, and reducing the risk of the cuvette 1 being dropped into the receiving aperture 14, with an associated jolt which may damage the cuvette 1 or dislodge some of the blood sample that has been collected.

The presence of the grooves 22, which receive and cooperate with protrusions 9 provided on the underside of the cuvette 1, will also allow the cuvette 1 to be clearly registered with respect to the receiving aperture 14.

If the protrusions 9 are not, for any reason, placed into the grooves 22, then the main body 2 of the cuvette 1 will not lie flat with respect to the disc 12, and this will be easy for a user to see. If the cuvette 1 does not fit properly into the receiving aperture 14 for this reason, it would be a straightforward matter for the user to grasp and move the upstanding region of the cuvette 1 and move it until the protrusions 9 are aligned with the grooves 22, at which point the cuvette 1 will drop into alignment with the plane of the disc 12.

Once the cuvette 1 has been placed into the receiving aperture 14, in the manner shown in figure 4, centrifuging of the cuvette 1 can begin. The disc 12 is rotated around its central axis, and in preferred examples of the invention, the disc may rotate at, for example, between 2,000 and 4,000 RPM, for instance at 3,500 RPM.

The skilled reader will appreciate that when the disc 12 rotates in this manner, forces will act on the cuvette 1 which will tend to drive the cuvette 1 outwardly with respect to the disc 12 i.e., radially away from the central axis thereof, and towards the outer edge 18. The cuvette 1 will therefore move radially outwardly with respect to the disc 12, and the rear end 5 of the cuvette 1 will move into the region 24 which is under the lip 21.

Figure 5 shows the position after the cuvette 1 has begun to move in this manner, with the rear end 5 of the cuvette within the region 24 under the lip p 28 between the rear end 5 of the cuvette 1 and the inner end wall 29 of the receiving aperture 14.

As rotation of the disc 12 continues, the cuvette 1 will continue to be driven 5 radially outwardly. Figure 6 shows the position where the cuvette 1 has been driven radially outwardly as far as possible, and where the rear end 5 of the cuvette 1 contacts the inner end wall 29. At this point, radial movement of the cuvette 1 with respect to the disc 12 will stop.

The presence of the overhanging lip 21 helps to maintain the position of the cuvette 1 during centrifugation. The radial position of the cuvette 1, with respect to the disc 12, is fixed and maintained by contact between the rear end 5 of the cuvette 1 and the inner end wall 29. Rapid rotation of the disc 12, leading to relatively high radial forces acting on the cuvette 1, will serve to engage the cuvette 1 with increasing firmness against the inner end wall 29.

Moreover, the fact that the planar rear end 5 of the cuvette 1 is received in the space 24 underneath the overhanging lip 21 means that the orientation of the cuvette 1 with respect to the disc 12 is maintained. The plane of the main body 2 of the cuvette 1 is maintained in an orientation which is parallel or substantially parallel with the plane of the disc 12. No significant deviation from this alignment is possible, because of the interaction between the rear end 5 of the cuvette 1 and the overhanging lip 21.

It will also be understood that if, for any reason, forces acted on the cuvette 1 which would tend to lift the tip 34 of the cuvette 1 out of the receiving aperture 14 (and so to rotate the main body 2 of the cuvette 1 out of the plane of the disc 12), any significant movement of the cuvette 1 in this way would be prevented by the presence of the lip 21.

jing process is complete, rotation of the disc 12 will stop. Once the cuvette 1 is to be removed, the cuvette 1 may be grasped by the user and moved toward the inner end 16 of the receiving aperture 14. Once this has been done the rear end 5 of the cuvette 1 will no longer be within the region 24 under the overhanging lip 21, and the cuvette 1 may simply be removed from the disc 12 by lifting the cuvette 1 directly away from the plane of the disc 12. The finger holes 20 will assist the user in grasping the cuvette 1 easily during this process.

Figure 7 shows a close-up view of the region of the outer end 17 of the receiving aperture 14, according to a preferred embodiment of the invention.

As discussed above, the disc 12 has an overhanging lip 21, with a region 24 defined beneath the overhanging lip 21, and a radially inward-facing end wall 29.

In the embodiment shown in figure 7, where the inward-facing end wall 29 meets the underside 31 of the overhanging lip 21 there is an angled surface 30. This angled surface 30 is preferably set at an angle of between around 30° and 60°, and more preferably is set at around 45° with respect to the plane of the disc 12.

The rear end 5 of the cuvette 1 is also shown in figure 7. In the position shown in figure, the rear end 5 is not fully inserted into the space 24 beneath the overhanging lip 21.

As can be seen in figure 7, the depth of the cuvette 1 is less than the depth of the space 24 beneath the lip 21. However, the depth of the cuvette 1 is approximately the same as, or greater than, the depth between the upper surface 26 of the receiving aperture 14, and the point where the angled surface 30 meets the inward-facing end wall 29.

The angled surface 30 is not essential, however, and in other embodiments the angled surface 30 may not be present. In such embodiments, the end wall 29 may meet the underside 25 of the lip 21, and the upper surface 26 of the receiving aperture 14, at right-angles.

) situation once the centrifugation process is fully underway. As can be seen in this figure, the cuvette 1 has been driven radially outwardly with respect to the disc 12, so that the rear end 5 of the cuvette 1 is pushed as far as possible radially outwardly with respect to the disc 12. As this occurs, the rear end 5 of the cuvette 1 will interact with the inclined surface 30, and will be pushed downwardly with respect to the plane of the disc 12. At this point, further motion of the cuvette 1 with respect to the disc 12 will stop.

As the skilled reader will appreciate, the presence of the inclined plane 30 allows the radial position of the cuvette 1 with respect to the disc 12 to be maintained, and also allows the angular orientation of the cuvette 1 with respect to the plane of the disc 12 to be controlled and maintained, through contact between the bottom surface 8 of the cuvette 1 and the upper surface 26 of the receiving aperture 14. The skilled reader will appreciate that the faster the disc 12 is rotated, the greater the outward radial forces that will act on the cuvette 1, and therefore the more firmly the position and orientation of the cuvette 1 with respect to the disc 12 will be maintained.

The skilled reader will appreciate that the distance between the upper surface 26 of the receiving aperture 14, and the underside 31 of the overhanging lip 21, must be greater than the depth of the rear end 5 of the cuvette 1, or the cuvette 1 will not fit reliably into the space 24 under the lip 21.

If the inclined plane 30 was not present, the rear end 5 of the cuvette 1 may therefore move with respect to the disc 12 during centrifuging, particularly since the centrifuging process may give rise to vibration of the disc 12.

However, the presence of the inclined plane 30 means that the position and angular orientation of the cuvette 1 with respect to the disc 12 will be firmly maintained, thus increasing the ease and reliability with which the liquid sample in the cuvette may be analysed.

f the invention, the rear end 5 of the cuvette 1 may include an inclined plane (not shown), having an angle which matches or substantially matches the angle of the inclined plane 30 which is formed as part of the disc.

In preferred embodiments of the invention, the cuvette 1 is symmetrical or substantially symmetrical about the plane of the main body 2, and inclined planes may therefore be formed whether both the top surface 7 and the bottom surface 8 meet the rear end surface 37 of the cuvette 1 In the example discussed above, the lip 21 extends from the end wall 29 of the receiving aperture 14. However, in other embodiments a space 38 may be present between the end wall 29 and the lip 21, and this is shown in figure 9. As the skilled reader will understand, the lip 21 is supported in this example through connection to (or being formed integrally with) regions of the disc 12 to either side of the receiving aperture 14.

In one example, the total length of the cuvette 1 is 78.9 mm, and the length of the lip 21 is 3.46 mm at the centre of the receiving aperture, and 7.23 mm at the side edges 35, 36. In general, it is preferred for the lip 21 to be of a length such that, if the rear end 5 of the cuvette 1 is fully received in the space 24 below the lip 21, and the cuvette 1 rotates so that its front end 3 lifts upwardly out of the receiving aperture 14, the movement of the centre of gravity of the Guyette 1 cannot move upwardly by more than half of the thickness of the cuvette 1. In the present example this corresponds to a maximum angle of rotation for the cuvette of 3.810.

On this basis the minimum length of the lip 21 is around 5.4 mm (where the lip 21 has a length that varies across its width, for instance as shown in figure 2, this applies to the longest part of the lip 21).

It is preferable for the lip not to have a length which is much greater than this, since the lip will be effective at holding the cuvette 1 in place, but may be so long that the disc 12 needs to be excessively large in order to allow the cuvette to be accommodated, or so long that it is awkward for a user to remove the cuvette 1 from the lip 21 following a centrifuging operation.

diments the depth of the cuvette is 4.95 mm, and the depth of the receiving aperture is around 5.34 mm.

In preferred embodiments, the length of the lip is at least 5% of the length of the receiving aperture. The length of the lip may preferably be at least 7% of the length of the receiving aperture. In further embodiments the length of the lip may be at least 10% of the length of the receiving aperture In absolute terms, in preferred embodiments the length of the lip may be at least 10 3mm. More preferably the length of the lip may be at least 5mm. Yet more preferably the length of the lip may be at least 7mm.

Where the length of the lip 21 varies across its width (as in the example shown in figure 2), the lengths discussed above preferably refer to the longest part or parts of the lip 21. In this example, the longest parts are those nearest the side edges 35, 26 of the receiving aperture.

In the examples shown, the lip 21 is provided at or near an end wall 29 which is at the point of the receiving aperture 14 which is furthest from the axis of rotation of 20 the disc 12. However, this need not be the case.

With reference to figure 10, a further example of a cuvette 40 embodying the present invention is shown. The further cuvette 40 is similar to the cuvette 1 shown in figure 1, with the exception that it has a pair of retention arms 41 protruding from the respective side edges 32, 33 thereof. Each retention arm 41 has a straight or substantially straight edge 42 on a side thereof which faces generally away from the tip 34 of the cuvette 40, and is perpendicular or substantially perpendicular to the longitudinal axis of the cuvette 40.

In the example shown the retention arms 41 are arranged generally symmetrically on either side of the cuvette 40.

a further receiving aperture 43 suitable for use with the further cuvette 40. The further receiving aperture 43 is similar to the retention aperture 14 discussed above, with the following differences.

The further receiving aperture 43 does not have an overhanging lip at its outer end 17.

The further receiving aperture 43 has a pair of receiving areas 44 which protrude outwardly from the side edges 35, 36 thereof. Each receiving area 44 is dimensioned to receive one of the retention arms 41.

Each receiving area 44 has an end wall 45, which faces generally towards the axis of rotation of the disc 12, and is perpendicular or substantially perpendicular to the longitudinal axis of the cuvette 40. An overhanging lip 46 is provided in the region of each end wall 45, such that it is spaced apart from the upward facing surface 26 of the receiving aperture 43, and defines a space between the underside of the lip 46 and the upward facing surface 26 of the receiving aperture 43. The skilled reader will realise that the lip 46 of each receiving area 44 is similar to the lip 21 of the example shown in figures 2 to 9.

In use, the further cuvette 40 is placed into the further receiving aperture 43, such that each retention arm 41 lies in one of the receiving areas 44. Upon subsequent centrifugation of the disc 12, the cuvette 40 will be driven radially outwardly with respect to the disc 12, and the straight edge 42 of each of the retention arms 41 will move into the region under the lip 46 of the respective receiving area 44.

This situation is shown in figure 12. The edges 42 of the retention arms 41 are shown in figure 12 for the purposes of clarity, although it should be understood that these edges 42 would be hidden behind the lips 46 of the respective receiving 30 areas 44.

The skilled reader will appreciate that, for similar reasons to those discussed above in relation to the embodiments shown in figures 1 to 9, the interaction between the overhanging lips 46 and the retention arms 41 will hold the cuvette 40 17 respect to the receiving aperture 43 during the centrifugation process.

An angled surface, similar to that described above in relation to the embodiment 5 shown in figures 7 and 8, may be provided in the space under each of the lips 46.

In the embodiment of figures 10 to 12, the cuvette 40 may be held in place with additional reliability, since the cuvette 40 is held in place with respect to the receiving aperture 43 in two separate places, and is also held in place at locations which are closer to the middle of the cuvette 40 (in the direction from the tip 34 of the cuvette 40 to the rear end 5 thereof).

In a yet further embodiment (not shown), the receiving aperture may have receiving areas 44 as shown in figures 11 and 12, as well as a lip 21 which overhangs the outer end 17 thereof, as shown in figures 2 to 9. The skilled reader will appreciate that this combination of features will hold the cuvette in place with additional reliability.

In conventional centrifuges which make use of a rotating component such as a disc, where the disc has an aperture in which a sample holder such as a cuvette is received to lie generally in the plane of the disc, it is conventional to have a lid or cover which is placed over the disc during the centrifuging process. The cover may be hinged with respect to the main body of the centrifuge, or may be fully removable. In use the user lifts the cover upwardly to expose all or part of the disc, inserts one or more sample holders into corresponding apertures in the disc, and then closes and secures the cover before rotation of the disc begins. The centrifuge may have a safety interlock system which prevents the disc from being driven to rotate if the cover is not properly closed.

In embodiments of the invention, the centrifuge may not have a lid or cover which covers the upper side of the disc 12. In use, when the disc 12 is driven to rotate as part of a centrifuging process, at least part of the disc 12 is exposed and may be accessed. In particular, when the disc 12 is stationary the receiving aperture 14 may be exposed, allowing the user to place the cuvette 1, 40 into the receiving o further lid or cover is moved into place to cover the disc 12 before the centrifuging process begins. In some embodiments, all or substantially all of the upper surface 13 of the disc 12 is exposed during the centrifuging process.

This is possible because the cuvette 1, 40 will be held firmly in place during the centrifuging process by the presence of the one or more lips 21, 46. By contrast, with a conventional system in which a sample holder is placed into an aperture in an upper surface a disc, where the aperture has no associated lip, the cuvette is very likely to fly out of the aperture during a centrifuging operation, posing a serious hazard to users.

The absence of a requirement for a lid or cover will make centrifuges according to the invention yet more straightforward and user-friendly, particularly for those with reduced or impaired vision and/or dexterity. The lack of a lid or cover will also reduce the weight and cost of the centrifuge.

In other embodiments, however, the centrifuge may have a lid or cover which covers the upper side of the disc 12 during centrifuging.

The skilled reader will appreciate that embodiments of the invention provide a system for collecting and analysing a liquid sample, which may easily be used by a person who is a non-specialist and has not received significant training in use of the system, and in particular a user who may have impaired dexterity and/or sight.

This is particularly important for use of the invention for the monitoring of the health of subjects in their own homes, where the subjects may be elderly and/or suffering from one or more illnesses or conditions.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

also broadly consist in the parts, elements, steps, examples and/or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and/or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein.

Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure.

Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and/or to encompass equivalents.

Claims

CLAIMS1. A centrifuge comprising a rotor, which may be driven to rotate during a centrifuging process, the rotor having an axis of rotation and an outer edge, 5 wherein: the rotor has an aperture for receiving a sample holder, the aperture being formed in a first surface of the rotor and being positioned between the axis of rotation and the outer edge, the aperture having an internal surface on which the sample holder may be received; the aperture has an end wall which faces generally towards the axis of rotation; and the rotor includes a lip, which overlies a part of the aperture in the region of the end wall, the lip being spaced apart from the internal surface and defining a region between the internal surface and an underside of the lip.
2. A centrifuge according to claim 1, wherein the aperture has an inner end, which lies closest to the axis of rotation, an outer end, which lies closest to the outer edge, and wherein the lip overlies a part of the aperture at or near the outer end.
3. A centrifuge according to claim 1 or 2, wherein the rotor has a first surface, in which the aperture is formed, and wherein the internal surface is offset from the first surface of the rotor.
4. A centrifuge according to claim 3 wherein, in the region of the lip, the lip is parallel or substantially parallel with the first surface of the rotor.
5. A centrifuge according to claim 3 or 4 wherein, in the region of the lip, an upper surface of the lip is aligned or substantially aligned with the first surface of the rotor.
6. A centrifuge according to any one of claims 3 to 5, wherein the aperture does not pass all the way through a thickness of the rotor.
7. A centrifuge according to any one of claims 3 to 6, wherein the first surface of the rotor is an upper surface thereof.
8. A centrifuge according to claim 7, when dependent upon claim 6, wherein 5 the rotor has a lower surface, the thickness of the rotor being defined between the upper and lower surfaces.
9. A centrifuge according to any preceding claim, wherein the lip adjoins the end wall.
10. A centrifuge according to any preceding claim, wherein a deflecting surface is formed, extending between the end wall and the underside of the lip, the deflecting surface subtending an angle with both the end wall and the underside of the lip.
11. A centrifuge according to any one of claims 1 to 9, wherein a deflecting surface is formed, extending between the end wall and the internal surface, the deflecting surface subtending an angle with both the end wall and the internal surface.
12. A centrifuge according to any preceding claim, wherein in the region of the lip the aperture has a width, and the lip extends all or substantially all of the way across the width.
13. A centrifuge according to any preceding claim, wherein the length of the lip is at least 5% of the length of the aperture.
14. A centrifuge according to any preceding claim, further comprising a housing, in which the rotor is mounted, and a drive arrangement to drive rotational motion of the rotor.
15. A centrifuge according to any preceding claim, wherein the centrifuge does not have a cover which is placed directly over the aperture during a centrifuging process.
16. A centrifuging apparatus, comprising: a centrifuge according to any preceding claim; and a Guyette, wherein the cuvette may be received in the aperture.
17. A centrifuging apparatus according to claim 16, wherein the cuvette may be placed into an initial position in the aperture by being advanced into the aperture in a direction which is substantially perpendicular to the axis of rotation of the rotor, so that the cuvette is received in regions of the aperture which are not the region between the internal surface and an underside of the lip.
18. A centrifuging apparatus according to claim 17 wherein, from the initial position, the cuvette may be moved in a direction passing from the axis of rotation of the rotor towards the outer edge thereof, without being removed from the aperture, into a second position, in which a part of the cuvette is received in the region between the internal surface and an underside of the lip.
19. A centrifuging apparatus according to claim 18 wherein, when the cuvette is in the initial position, rotation of the rotor about the axis of rotation at a sufficient rate will drive the cuvette into the second position.
20. A centrifuge apparatus according to any one of claims 16 to 19 wherein the aperture comprises one or more finger holes, comprising regions of the aperture which are not occupied by the cuvette when the cuvette is received in the aperture.
21. A centrifuge apparatus according to claim 20, when dependent upon claim 18, wherein the finger holes comprise regions of the aperture which are not occupied by the cuvette in either the initial position or the second position.
22. A centrifuge apparatus according to claim 20 or 21, wherein the aperture comprises two finger holes, which extend from the aperture from substantially opposite sides thereof.
23. A centrifuge apparatus according to any one of claims 20 to 22, wherein the or each finger hole extends from the aperture in a direction which is generally perpendicular to a direction passing from the axis of rotation of the rotor to the outer edge thereof.
24. A centrifuge apparatus according to claim 18 or any claim dependent thereon, wherein the cuvette has one or more projecting ridges, and the internal surface of the rotor has one or more corresponding grooves formed therein, and wherein, when the cuvette is placed in the first or second position, the one or more grooves are received in the respective grooves.
25. A centrifuge apparatus according to claim 24, wherein the cuvette may slide with respect to the internal surface from the first position to the second position, with the one or more grooves remaining in the respective grooves.