PIPETTE TIP

Abstract

A pipette tip made of plastic includes a tubular body having an inner circumference and an outer circumference. The tubular body includes a bottom end defining a bottom opening structured to enable passage of a liquid and a top end defining a top opening that clamps onto a mount of a pipetting device. A seat region for the mount is positioned proximate to the top opening and on the inner circumference of the tubular body. A plurality of flattenings extend in an axial direction on the outer circumference proximate to the top opening. The tubular body defines a contour of an arc polygon in a cross-section through the flattenings on the outer circumference.

Claims

1. A pipette tip made of plastic and comprising: a tubular body including an outer circumference and an inner circumference, the tubular body comprises, a bottom end defining a bottom opening configured for passage of a liquid, a top end defining a top opening configured to clamp onto a mount of a pipetting device, a seat region for the mount positioned proximate to the top opening and on the inner circumference of the tubular body, and a plurality of flattenings extending in an axial direction on the outer circumference proximate to the top opening, wherein the tubular body comprises a contour of an arc polygon in a cross-section through the flattenings on the outer circumference.

2. The pipette tip according to claim 1, wherein the flattenings extend in an axial direction at least over part of the seat region.

3. The pipette tip according to claim 1, wherein the flattenings extend upward up to a distance from the top end of the tubular body.

4. The pipette tip according to claim 1, wherein the flattenings extend up to the top end the tubular body.

5. The pipette tip according to claim 1, wherein the flattenings extend downward to a shoulder on the outer circumference of the tubular body.

6. The pipette tip according to claim 1, wherein the tubular body comprises at least three flattenings.

7. The pipette tip according to claim 1, wherein in a cross-section through the tubular body, each of the plurality of flattenings are at least one of: (1) equally wide; and (2) equally curved.

8. The pipette tip according to claim 1, wherein in a cross-section through the flattenings of the tubular body, the tubular body comprises the contour of a regular arc polygon.

9. The pipette tip according to claim 1, wherein the flattenings run parallel to a center axis of the tubular body.

10. The pipette tip according to claim 1, wherein the flattenings are oriented helically around a center axis of the tubular body.

11. The pipette tip according to claim 1, wherein in a cross-section through the flattenings, the tubular body comprises a circular contour on the inner circumference.

12. The pipette tip according to claim 1, wherein the tubular body comprises at least one sealing structure positioned on the inner circumference of the seat region, wherein the sealing structure is configured to project inward and run.

13. The pipette tip according to claim 1, wherein the tubular body comprises at least one inwardly projecting braking structure running in a circumferential direction.

14. The pipette tip according to claim 13, wherein the tubular body comprises at least one of: (1) several sealing structures; (2) guide structures; and (3) braking structures on the inner circumference and comprising a wave-shaped contour in a longitudinal section through the tubular body.

15. The pipette tip according to claim 1, wherein the tubular body comprises a widening at the top opening.

16. The pipette tip according to claim 13, wherein the tubular body comprises a thermoplastic.

17. The pipette tip according to claim 1, wherein the tubular body further comprises at least one of the following: (1). a wall thickness of the tubular body at a corner of the arc polygon falls within a range of 0.3 to 1 mm; (2) the seat region is internally conical with a downwardly tapering diameter, wherein the cone angle of the seat region is in a range of 1° to 6°; (3) the seat region is configured to be mounted on a mount, wherein a cone angle of the mount or of a conical section of the mount is in a range of 1.0° to 10°; (4) the wall thickness of the tubular body in a region of the flattenings is a maximum of 0.3 mm; (5) the wall thickness of the tubular body in the region of the flattenings is a minimum of 0.1 mm; (6) the flattenings extend in the longitudinal direction of the tubular body over a length of at least 4 mm; and (7) the flattenings extend in the longitudinal direction of the tubular body at least over one of: (i) two sealing structures; (ii) guide structures; (iii) braking structures.

18. The pipette according to claim 14, wherein the at least one of: (1) the sealing structure; (2) the guide structure; and (3) the braking structure are distributed in the longitudinal direction of the tubular body over the seat region.

19. A pipette tip system comprising: a plurality of pipette tips, wherein each of the plurality of pipette tips includes an outer circumference and an inner circumference and further includes, a tubular body that comprises, a bottom end defining a bottom opening configured for passage of a liquid, a top end defining a top opening configured to clamp onto a mount of a pipetting device, a seat region for the mount positioned proximate to the top opening and on the inner circumference of the tubular body, and a plurality of flattenings extending in an axial direction on the outer circumference proximate to the top opening, wherein the tubular body comprises a contour of an arc polygon in a cross-section through the flattenings on the outer circumference, wherein the plurality of pipette tips comprises different pipette tips of different pipette types, wherein the flattenings of the different pipette tips of the different pipette tip types comprise flattenings that are at least one of: (1) differently configured; and (2) comprise different identifications on the flattenings.

20. A pipetting system comprising: at least one pipette tip having a tubular body defining an outer circumference and an inner circumference, the tubular body comprises, a bottom end defining a bottom opening configured for passage of a liquid, a top end defining a top opening configured to clamp onto a mount of a pipetting device, a seat region for the mount positioned proximate to the top opening and on the inner circumference of the tubular body, and a plurality of flattenings extending in an axial direction on the outer circumference proximate to the top opening; and at least one of: (1) a single channel pipetting device comprising a single mount configured for mounting a pipette tip; and (2) a multichannel pipetting device comprising a plurality of mounts configured for simultaneously mounting a plurality of pipette tips, wherein the tubular body comprises a contour of an arc polygon in a cross-section through the flattenings on the outer circumference, and a single channel pipetting device having a single mount for mounting a pipette tip, and/or a multichannel pipetting device with a plurality of mounts for simultaneously mounting a plurality of pipette tips.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The invention will be explained in more detail below with reference to the accompanying drawing of exemplary embodiments. In the drawing:

[0052] FIG. 1a illustrates a side view of an embodiment of a pipette tip with a triangular arc polygon contour;

[0053] FIG. 1b illustrates the embodiment of FIG. 1a rotated by 90°;

[0054] FIG. 1c illustrates a sectional view of the embodiment of 1b taken along line C-C;

[0055] FIG. 1d illustrates a bottom view of the embodiment of 1a;

[0056] FIG. 1e illustrates a top view of the embodiment of 1a;

[0057] FIG. 1f illustrates a perspective view of the embodiment of FIG. 1a;

[0058] FIG. 1g illustrates another perspective view of the embodiment of FIG. 1a

[0059] FIG. 2a illustrates a side view of an embodiment of a pipette tip with a triangular arc polygon contour with rounded edges;

[0060] FIG. 2b illustrates the embodiment of FIG. 2a rotated by 90°;

[0061] FIG. 2c illustrates a sectional view of the embodiment of 2b taken along line C-C;

[0062] FIG. 2d illustrates a bottom view of the embodiment of 2a;

[0063] FIG. 2e illustrates a top view of the embodiment of 2a;

[0064] FIG. 2f illustrates a perspective view of the embodiment of FIG. 2a;

[0065] FIG. 2g illustrates another perspective view of the embodiment of FIG. 2a

[0066] FIG. 3a illustrates a side view of an embodiment of a pipette tip with a rectangular arc polygon contour;

[0067] FIG. 3b illustrates the embodiment of FIG. 3a rotated by 90°;

[0068] FIG. 3c illustrates a sectional view of the embodiment of 3b taken along line C-C;

[0069] FIG. 3d illustrates a bottom view of the embodiment of 3a;

[0070] FIG. 3e illustrates a top view of the embodiment of 3a;

[0071] FIG. 3f illustrates a perspective view of the embodiment of FIG. 3a;

[0072] FIG. 3g illustrates another perspective view of the embodiment of FIG. 3a;

[0073] FIG. 4a illustrates a side view of another embodiment of a pipette tip with a triangular arc polygon contour;

[0074] FIG. 4b illustrates the embodiment of FIG. 4a rotated by 90°;

[0075] FIG. 4c illustrates a sectional view of the embodiment of 4b taken along line C-C;

[0076] FIG. 4d illustrates a bottom view of the embodiment of 4a;

[0077] FIG. 4e illustrates a top view of the embodiment of 4a;

[0078] FIG. 4f illustrates a perspective view of the embodiment of FIG. 4a;

[0079] FIG. 4g illustrates another perspective view of the embodiment of FIG. 4a;

[0080] FIG. 5 illustrates stacked cross-sections through the seat region of pipette tips with an annular cross-section, flattenings with a straight profile, flattenings with an inwardly curved profile, and flattenings with the contour of a Reuleaux polygon; and

[0081] FIG. 6 illustrates a simulation of the overall deformation during a radial displacement at the inner circumference for pipette tips with different geometries.

DETAILED DESCRIPTION OF THE INVENTION

[0082] In the following explanation of different exemplary embodiments, the structures and components identified by the same names are given the same reference numbers.

[0083] According to FIG. 1, a pipette tip 1 has an elongated tubular body 2 that has a bottom opening 4 in the bottom end 3 and a top opening 6 in the top end 5. The bottom opening 4 is smaller than the top opening 6.

[0084] In general, the inner and the outer diameter of the tubular body 2 increase from the bottom opening 4 to the top opening 6. The tubular body 2 has a conical section 7 at the bottom, and above that, a head section 8 that is slightly conical in a bottom head section part 8.1 and is more strongly conical in a top head section part 8.2 (FIG. 1a, 10. Adjacent to the conical section 7, a downwardly directed outer shoulder 10 runs on the outer circumference 9 of the tubular body 2 around the bottom side of the head section 8.

[0085] The head section 8 of the tubular body 2 has a triangular cross-section and, between two respective adjacent corners 11, has a flattening 12 with an arc-shaped, outwardly curved profile 13 (FIG. 1d). Overall, the tubular body 2, in a cross-section through the head section 8, therefore has an outer contour 14 in the shape of a regular triangular arc polygon 15 that is also termed a Reuleaux triangle. Given the outer contour 14 in the shape of an arc polygon 15 and its circular inner contour 16, the head section 8 has places 17 with the thickest wall at the corners 11 of the arc polygon 15, and places 18 with the thinnest wall centrally between the corners, wherein its wall thickness gradually decreases from the places 17 with the thickest wall to the places 18 with the thinnest wall.

[0086] At the top, the tubular body 2 has a circumferential edge 19 with a corresponding wall thickness progression (FIG. 1g). At the top end 5, the tubular body 2 has a widening 21 with an insertion chamfer 22 on the inner circumference 20. This is shown in particular in FIG. 1c.

[0087] Next to the top opening 6, the tubular body 2 has a substantially conical seat region 23 on the inner circumference 20 for a conical mount 24 of a pipetting device 25. The seat region 23 extends into the head section 8 and has a cone angle of for example 2° to 6°. The seat region 23 forms a surface seal for a sealing seat of the pipette tip 1 on the mount 24.

[0088] On the inner circumference 20 below the seat region 23, the tubular body 2 has a circumferential ring groove 26 for holding on to the core of an injection mold when producing the pipette tips (FIG. 1c). At the bottom end of the head section 8, the inner contour of the tubular body 2 smoothly transitions into the downwardly tapering conical section 7 (FIG. 1c).

[0089] For clamping onto the mount 24 of a pipetting device 25, one or more pipette tips 1 can be kept ready in holes of a holder for pipette tips, wherein they are supported by the shoulder 10 on the edge of the holes. According to FIG. 1c, the mount 24 of a pipetting device 25 can be easily inserted into the pipette tip 1 at the top opening 6 through the widening 21 with the insertion chamfer 22. While being clamped onto the mount 24, the pipette tip 1 can be elastically and/or plastically deformed in the region of the flattenings 12, by which the mounting forces are reduced and a reliably sealing seat of the mount 24 in the seat region 22 is achieved with comparatively less mounting force. The thin-walled regions between the corners 11 bring about a reduction in the required expansion force when mounting the pipette tip 1 onto a mount 24 of a pipetting device 25, as well as correspondingly reduced mounting force and increased flexibility when using the pipette tip 1 with a pipetting device 25 that has mounts 23 with different geometries.

[0090] After pipetting liquid, the pipette tip 1 can be easily ejected from the mount 24 since the ejection forces to be applied for ejecting are also reduced. For ejection, an ejection sleeve of the pipetting device 25 guided onto the mount 24 is pressed against the circumferential edge 19 at the top end 5 of pipette tip 1, and the pipette tip 1 is scraped off of the mount 24. The thick-walled regions at the corners 11 allow the pipette tip 1 to be reliably ejected, since they offer a large support surface at the top edge 19 for mounting an ejector. Since the thick-walled regions are also formed on the shoulder 10 on the bottom side of the head section 8, they moreover create an effective support at the edge regions of holes in a holder for pipette tips. Moreover, the cross-sectional shape promotes an even distribution of stress when mounting on the mount 24, by which the pipette tip 1 is prevented from bursting in the head section 8. Finally, the cross-sectional shape of the head section 8 is also advantageous for evenly filling the injection mold with plasticized plastic compound during injection molding of the pipette tip 1.

[0091] The pipette tip 1 of FIG. 2 differs from the pipette tip of FIG. 1 in that it has rounded corners 11, i.e., corners 11 with a radius 27, in a cross-section through the head section 8. The radius 27 is smaller than the radius of curvature of the flattenings 12.

[0092] The pipette tip 1 of FIG. 3 differs from the pipette tip of FIG. 1 in that, in a cross-section through the head section 9, it has four flattenings 12 with an arched, outwardly curved profile 13, wherein the profiles 13 abut each other at four corners 11. The outer contour of this pipette tip 1 has the shape of a regular rectangular arc polygon 15 according to Reuleaux.

[0093] The advantageous effects of the pipette tip of FIG. 1 apply to a greater extent to the pipette tip of FIG. 3, given the high number of corners 11 and flattenings 12.

[0094] The pipette tip 1 of FIG. 4 is preferably designed to pipette smaller filling volumes (e.g., 10 μl) than the pipette tips 1 of FIGS. 1 to 3 (e.g., 200 μl). The pipette tip 1 of FIG. 4 differs from those described above in particular in that the elongated tubular body 2 has a conical central section 28 over the conical section 7, a conical transition section 29 above that, and a conical head section 8 above that with a circumferential flange 30 that projects radially outward at the top end 5. The aforementioned sections 7, 28, 29 and the flange 30 directly adjoin each other. The outer diameter of the tubular body 2 increases in principle gradually from the bottom end 3 to the flange 30. In the central section, it has small diameter projections 31 that form the fill level markers. The inner diameter of the tubular body 2 also increases in principle gradually from the bottom end 3 to the top end 5 of the tubular body 2.

[0095] On the inner circumference 20 in the seat region 23, the tubular body 2 has sealing structures 32 in the form of two inwardly projecting, unbroken, circumferential sealing beads 33 that are at a distance from each other in an axial direction. The bottom sealing bead 33 is simultaneously a braking structure 34 in the form of a braking bead 34 that has the function of stopping the insertion of a mount 24 of a pipetting device 25. To accomplish this, the bottom sealing bead 33 has a smaller inner diameter than the top sealing bead 33. Above the sealing bead 33, the seat region 23 has a guide structure 36 in the form of a plurality (e.g., 3) of guide bumps 37 or guide warts on the inner circumference that are evenly distributed over the same transverse cross-section. At the top end 5, the tubular body 2 has a widening 21 with an insertion chamfer 22 on the inner circumference 20 that terminates above the guide structure 36.

[0096] On the bottom side, the flange 30 has downwardly projecting ribs 38 that extend radially outward from the head section 8.

[0097] This pipette tip 1 also has three rounded corners 11 with radii 27 and three flattenings 12 with an arched, outwardly curved profile 13 between the corners 11. Starting from the bottom side of the flange 30, the flattenings 12 extend in an axial direction of the tubular body 2 up to the top edge region of the transition section 29.

[0098] One or more pipette tips 1 according to FIG. 4 can be provided in a holder for pipette tips. In this case, they are inserted into holes of the holder and are supported by the ribs 38 on the bottom side of the flange 30 on the edge of the holes. According to FIG. 4c, the mount 24 is only partially inserted into the pipette tip 1, as far as the guide structure 36. The mount 24 is advanced up to the sealing and braking bead 33, 35, such that the pipette tip 1 is clamped aligned and sealing onto the mount 24.

[0099] By way of comparison, FIG. 5 shows the cross-sections through the seat region 23 of a hollow cylindrical pipette tip 1.1, a pipette tip 1 with flattenings 12 with an outwardly curved profile 13 between adjacent cylindrical regions 39, a pipette tip 1.3 with flattenings 12 with a linear profile 40 between adjacent cylindrical regions 39, and a pipette tip 1.4 with the outer contour of a uniform triangular arc polygon 15.

[0100] All of the pipette tips 1.1 to 1.4 have the same maximum outer diameter and the same inner diameter.

[0101] In comparison to the hollow cylindrical pipette tip 1.1, the pipette tip 1.2 with outwardly curved flattenings 12 has a significantly reduced cross-sectional area and a significantly reduced wall thickness at the places 17 with the thinnest wall.

[0102] In comparison to the pipette tip 1.2 with the outwardly curved flattenings 12, the pipette tip 1.3 with the linear flattenings 12 has an even further reduced cross-sectional area and even further reduced wall thickness at the places 17 with the thinnest wall.

[0103] The pipette tip 1.4 with the outer contour of an arc polygon 15 has the smallest cross-sectional area and the smallest wall thickness at the places 17 with the thinnest wall.

[0104] The following table presents the cross-sectional areas in a cross-section through the seat region, and the necessary radial expansion forces for an expansion of 0.1 mm at the inner circumference, according to a simulation for pipette tips with different outer contours. Furthermore, the table presents the relative savings in the force for expansion for each cross-sectional shape relative to the pipette tip with a circular cross-section presented on the second line.

TABLE-US-00001 Cross- Cross- Relative sectional sectional Expansion savings No. shape area force in force 1 Thin annular ring 3.89 mm.sup.2 (1.668N) 0.4914/49.14% (t = 0.25 mm) 2 Thick annular ring 9.99 mm.sup.2 (3.394N)  1.0000/100.00% (t = 0.6 mm) 3 Annular ring with 9.74 mm.sup.2 (3.242N) 0.9554/95.54% 1× groove 4 Annular ring with 9.23 mm.sup.2 (2.940N) 0.8664/86.64% 3× groove 5 Annular ring with 7.46 mm.sup.2 (2.174N) 0.6408/64.08% 10× groove 6 Triangle tip 8.01 mm.sup.2 (2.682N) 0.7904/79.04% 7 Releaux triangle 5.89 mm.sup.2 (2.207N) 0.6504/65.04% 8 Releaux rectangle 5.84 mm.sup.2 (2.162N) 0.6370/63.70% 9 Releaux pentagon 5.82 mm.sup.2 (2.125N) 0.6224/62.24%

[0105] FIG. 6 shows the deformations (elastic comparative expansion) determined in a simulation of the cross-sections of the different pipette tips. Corresponding to the shade of gray, the extent of deformation is indicated by different shades of gray.

[0106] The pipette tip listed in line 1 has the smallest cross-sectional area and requires the least expansion force for a radial expansion of 0.1 mm to achieve the greatest relative savings in force. According to FIG. 16, however, the greatest deformations occur with this cross-sectional shape (maximum comparative expansion: 0.77=77%), such that the pipette tip tears easily.

[0107] The pipette tip from line 2 of the table with the thick annular cross-section has the largest cross-sectional area and the greatest expansion forces. According to FIG. 6, the deformation is comparatively slight (maximum comparative expansion: 0.60).

[0108] According to lines 3 to 5 of the table, the pipette tips having an annular cross-section with 1, 3 or 10 grooves have correspondingly reduced cross-sectional areas and required expansion forces, such that a certain relative savings in force is achieved. FIG. 6 shows that in the grooves, comparatively large deformations (maximum comparative expansion: 0.162; 0.160; 0.139) and stress occur, such that the pipette tips tear there fairly easily.

[0109] With the pipette tip having linear flattenings from line 6, a significantly greater reduction in the cross-sectional area as well as the necessary expansion force and a corresponding relative savings in force are achieved. FIG. 6 shows that the elastic deformations (elastic comparative expansion: 0.105) and stress are comparatively small, by which the pipette tip is protected from tearing in the seat region.

[0110] According to lines 7 to 9 of the table, the pipette tips with the outer contour in the shape of an arc polygon have even smaller cross-sectional areas and reduced expansion forces, as well as a greater relative savings in force. According to FIG. 6, the deformations (elastic comparative expansion: 0.83) and tension in the cross-section are reduced even further, such that better protection against tearing is afforded.

LIST OF REFERENCE SIGNS

[0111] 1 Pipette tip

[0112] 2 Tubular body

[0113] 3 Bottom end

[0114] 4 Bottom opening

[0115] 5 Top end

[0116] 6 Top opening

[0117] 7 Conical section

[0118] 8 Head section

[0119] 9 Outer circumference

[0120] 10 Shoulder

[0121] 11 Corner

[0122] 12 Flattening

[0123] 13 Curved profile

[0124] 14 Outer contour

[0125] 15 Arc polygon

[0126] 16 Inner contour

[0127] 17 Place with thickest wall

[0128] 18 Place with thinnest wall

[0129] 19 Circumferential edge

[0130] 20 Inner circumference

[0131] 21 Widening

[0132] 22 Insertion chamfer

[0133] 23 Seat area

[0134] 24 mount

[0135] 25 Pipetting device

[0136] 26 Ring groove

[0137] 27 Radius

[0138] 28 Central section

[0139] 29 Transitional section

[0140] 30 Flange

[0141] 31 Diameter projection

[0142] 32 Sealing structure

[0143] 33 Sealing bead

[0144] 34 Braking structure

[0145] 35 Braking bead

[0146] 36 Guide structure

[0147] 37 Guide bumps

[0148] 38 Rib