Pipette Tip

Abstract

A pipette tip made of plastic with an elongated tubular body with a lower opening at the lower end for the passage of liquid and an upper opening at the upper end for clamping onto an attachment of a pipetting device, wherein a seating region for the attachment is present next to the upper opening on the inner circumference of the tubular body, wherein at least one flattened area extending in the axial direction is present next to the upper opening on the outer circumference of the tubular body, the wall thickness of the tubular body gradually decreases in a cross-section through the tubular body, starting from one of the two regions of the tubular body adjoining the flattened area, in the flattened area towards its central region, and the flattened area has in the cross-section through the tubular body a straight or a less strongly curved profile than the adjoining regions.

Claims

1. A pipette tip made of plastic with an elongated tubular body (2) with a lower opening (4) at the lower end (3) for the passage of liquid and an upper opening (6) at the upper end (5) for clamping onto an attachment (21) of a pipetting device, wherein a seating region (20) for the attachment (21) is present next to the upper opening (6) on the inner circumference of the tubular body (2), characterized in that at least one flattened area (12) extending in the axial direction is present next to the upper opening (6) on the outer circumference (11) of the tubular body (2), the wall thickness of the tubular body (2) gradually decreases in the flattened area (12) towards its central region (27) in a cross-section through the tubular body (2), starting from one of the two regions (13) of the tubular body (2) adjacent to the flattened area (12), and the flattened area (12) has in the cross-section through the tubular body (2) (i) a straight profile or (ii) a profile (15) that is less strongly curved than the adjoining regions (13).

2. The pipette tip according to claim 1, in which the tubular body (2) has, in a cross-section on the outer circumference (11) in the regions (13) adjoining the flattened area (12), a circularly curved profile (14) and has in the flattened area a straight profile (15) or a circular profile with a larger curvature radius than in the regions (13) adjoining the flattened area (12).

3. The pipette tip according to claim 1, in which the tubular body (2) has in the flattened area (12) a straight and/or a curved profile (15) in all cross-sections through the at least one flattened area (12).

4. The pipette tip according to claim 1, in which the at least one flattened area (12) extends in the axial direction at least over a part of the seating region (20).

5. The pipette tip according to claim 1, in which the at least one flattened area (12) extends upwards up to a distance from the upper end (5) of the tubular body (2).

6. The pipette tip according to claim 1, in which the at least one flattened area (12) extends up to the upper end (5) of the tubular body (2).

7. The pipette tip according to claim 1, in which the at least one flattened area (12) extends downwards to a shoulder (10) on the outer circumference (11) of the tubular body (2) or beyond it.

8. The pipette tip according to claim 1, in which the tubular body (2) has multiple, preferably three, flattened areas (12) on the circumference.

9. The pipette tip according to claim 1, in which the flattened areas (12) are distributed uniformly over the outer circumference (11) of the tubular body (2).

10. The pipette tip according to claim 8, in which the flattened areas (12) take up a larger part of the outer circumference (11) of the tubular body (2) overall than the regions (13) of the tubular body (2) adjoining them in the circumferential direction overall.

11. The pipette tip according to claim 1, in which, in the cross-section through the tubular body (2), multiple flattened areas with a straight profile define an outer circumference (11) of the tubular body (2) in the form of a polygon, preferably of a regular polygon.

12. The pipette tip according to claim 1, in which the tubular body (2) has on the inner circumference (17) of the seating region (20) at least one sealing structure (22) projecting inwards and running in the circumferential direction and/or at least one guide structure (24) projecting inwards and running in the circumferential direction or having multiple portions spaced apart from each other and/or at least one braking structure (26) projecting inwards and running in the circumferential direction or having multiple portions spaced apart from each other.

13. The pipette tip according to claim 12, in which the tubular body (2) has on the inner circumference (17) multiple sealing structures (22) and/or guide structures (24) and/or braking structures (30) that have a wave-like contour in a longitudinal section through the tubular body (2).

14. The pipette tip according to claim 1, in which the tubular body (2) has a widened area (18) and/or an insertion bevel (19) on the upper opening (6).

15. The pipette tip according to claim 1, which is produced from at least one thermoplastic, preferably from at least one polyolefin, preferably from at least one polypropylene and/or ethylene.

16. The pipette tip according to claim 1 with one or more of the following features: the wall thickness of the tubular body in the circumferential direction next to the at least one flattened area falls in the range from 0.3 to 1 mm, the seating region is conical on the inside with the diameter decreasing toward the bottom, wherein the cone angle of the seating region is selected from the range of 1° to 6°, preferably 1.5° to 2.5°, the seating region is designed to be mounted onto an attachment, wherein the cone angle of the conical attachment or of the conical portion of the attachment is selected from the range of 1.0° to 10°, preferably from the range of 1.3° to 7°, further preferably from the range of 1.5° to 3°, the sealing structure and/or guide structure and/or braking structure are distributed over the seating region in the longitudinal direction of the tubular body, the wall thickness of the tubular body is at most 0.3 mm at the thinnest location in the region of the flattened area (outside of the sealing structure and/or guide structure and/or braking structure), the wall thickness of the tubular body is at a minimum 0.1 mm at the thinnest location in the region of the flattened area (outside of the sealing structure and/or guide structure and/or braking structure), the flattened area extends in the longitudinal direction of the tubular body over a length of at least 4 mm, the flattened area extends in the longitudinal direction of the tubular body at least across two sealing structures and/or guide structures and/or braking structures.

17. A pipette tip system comprising multiple pipette tips (1) according to claim 1, wherein pipette tips of different pipette tip types have differently designed flattened areas (12) and/or different markings on the flattened areas (12).

18. A pipetting system comprising at least one pipette tip according to claim 1 and a single-channel pipetting device with a single attachment (21) for mounting a pipette tip (1) and/or a multichannel pipetting device with multiple attachments (21) for simultaneously mounting multiple pipette tips (1).

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0065] The invention is explained in more detail below based on the accompanying drawing of exemplary embodiments. In the drawings:

[0066] FIG. 1 shows a pipette tip in a perspective view from the side;

[0067] FIG. 2 shows the same pipette tip in a scaled-down side view;

[0068] FIG. 3 shows the same pipette tip in a cross-section through the seating region;

[0069] FIG. 4 shows the same pipette tip in an enlarged partial section through the seating region;

[0070] FIG. 5 shows the same pipette tip in a scaled-down partial section through the seating region with an attachment of a pipetting device inserted;

[0071] FIG. 6 shows another pipette tip in a perspective view from the side;

[0072] FIG. 7 shows the same pipette tip in an enlarged side view;

[0073] FIG. 8 shows the same pipette tip in a cross-section through the seating region;

[0074] FIG. 9 shows the same pipette tip in an enlarged partial portion through the seating region;

[0075] FIG. 10 shows the same pipette tip in the enlarged partial portion through the seating region with an attachment of a pipetting device inserted.

DETAILED DESCRIPTION OF THE INVENTION

[0076] In the following explanation of various exemplary embodiments, the structures and components referred to with the same designations are provided with the same reference signs.

[0077] According to FIGS. 1 to 4, a pipette tip 1 has an elongated tubular body 2 which has a lower opening 4 on the lower end 3 and an upper opening 6 on the upper end 5. The lower opening 4 is smaller than the upper opening 6.

[0078] Generally, the inner and the outer diameters of the tubular body 2 increase from the lower opening 4 toward the upper opening 6. The tubular body 2 has at the bottom a conical beginning portion 7, above it a middle portion 8 with a smaller cone angle than the beginning portion 7, and above that a cylindrical head portion 9 with larger dimensions than the middle portion 8. Adjoining the middle portion 8, an outer shoulder 10 oriented downward runs on the underside of the head portion 9 on the outer circumference of the tubular body 2.

[0079] On the outer circumference 11 of the head portion, flattened areas 12 extending in the axial direction are present. In the example, there are three flattened areas 12. The flattened areas 12 begin at a small distance from the upper end 5 of the tubular body 2 and extend downward past the head portion 9 until approximately past the shoulder 10 into the upper region of the middle portion 8. The flattened areas 12 are aligned parallel to the central axis of the tubular body 2. The flattened areas 12 are arranged uniformly distributed around the outer circumference 11 of the tubular body. In the example, the flattened areas 12 are each approximately the same width as the adjoining regions 13.

[0080] The tubular body 2 has, in each cross-section through the flattened areas 12 on the outer circumference 11, a circular curved profile 14 in the regions 13 adjoining the flattened areas 12 and a straight profile 15 in the flattened areas 12. The circular profiles 14 extend across the entire distance range between two adjacent flattened areas 12, i.e., the profiles 14 are circular everywhere between the flattened areas 12. This is shown in particular in FIG. 3.

[0081] Above the flattened areas 12, the tubular body 2 has a circumferential edge 16 with a uniform wall thickness.

[0082] On the upper end, the tubular body 2 has on the inner circumference 17 a widened area 18 with an insertion bevel 19. This is shown in particular in FIG. 4.

[0083] Next to the upper opening 6, the tubular body 2 has on the inner circumference 17 a substantially conical or cylindrical seating region 20 for a conical or cylindrical attachment 21 of a pipetting device. The seating region 20 extends into the head portion 9 and is conical with a cone angle of, for example, 2° to 6°.

[0084] The tubular body 2 has on the inner circumference 17 in the seating region 20 multiple sealing structures 22 in the form of inwardly projecting sealing beads 23 running in a circumferentially closed manner which are spaced apart from each other in the axial direction. Furthermore, the tubular body 2 has, at a small distance from the upper opening 6, inwardly projecting guide structures 24 running in a circumferentially closed manner in the form of guide beads 25 which are spaced apart from each other. Overall, the tubular body 2 has in the seating region 20 sealing and guide structures 22, 24 that are wave-like in longitudinal section.

[0085] Below the sealing structures 22, a conical braking region 26 is present on the inner circumference of the head portion 9.

[0086] On the lower end of the head portion 9, the inner contour of the tubular body 2 transitions smoothly into the downwardly tapering middle portion 8, which transitions into the beginning portion 7 farther down.

[0087] According to FIG. 3, the tubular body 2 has in the cross-section a constant wall thickness overall in the adjoining regions 13 between the flattened areas 12. Furthermore, the wall thickness of the tubular body 2 decreases in the flattened areas 12, in each case starting from the adjoining regions 13, toward the central region 27 of the flattened areas 12.

[0088] According to FIGS. 1 and 2, the flattened areas 12 are provided with markings 28. These are thereby labels 29 in the form of raised or indented numbers and letters, which are generated during injection molding of the pipette tip 1. The labels 29 indicate the pipette tip size and the nest of the injection molding tool in which the pipette tip 1 is injection molded.

[0089] For clamping onto the attachment 21 of a pipetting device, one or more pipette tips 1 can be kept ready in holes of a holder for pipette tips, wherein they are supported with the shoulder 10 on the edge of the holes. According to FIG. 5, the attachment 21 of a pipetting device can be easily inserted into the pipette tip 1 through the widened area 18 with the insertion bevel 19 on the upper opening 6. It is guided therein in a low-friction manner by the guide structures 24 and the sealing structures 22. When clamping onto the attachment 21, the pipette tip 1 can be elastically and/or plastically deformed in the region of the flattened areas 12, as a result of which the mounting forces are decreased and a secure seal of the attachment 21 on the sealing structures 22 is achieved with relatively lower mounting forces.

[0090] After the pipetting of liquid, the pipette tip 1 can be easily ejected from the attachment 21, since the ejection forces to be applied for ejection are also reduced. For the ejecting, an ejection sleeve of the pipetting device guided on the attachment 21 is pressed against the circumferential edge 16 on the upper end 5 of the pipette tip 1 and the pipette tip is stripped off the attachment 21.

[0091] The pipette tip 1 from FIGS. 6 to 10 is preferably designed for pipetting smaller filling volumes than the pipette tip 1 from FIGS. 1 to 5. The pipette tip 1 differs from the one described above in particular in that the elongated tubular body 2 has, above the conical beginning portion 7, multiple conical middle portions 8.1, 8.2, 8.3, above that a conical transition portion 30 and above that a conical head portion 9 with a circumferential, radially outwardly projecting flange 31 on the upper end 5. The previously designated portions 7, 8.1, 8.2, 8.3, 40 and the flange 31 connect directly to each other. The outer diameter of the tubular body 2 enlarges gradually from the lower end 3 to the upper end of the head portion 9. The inner diameter of the tubular body 2 also in principle enlarges gradually from the lower end 3 to the upper end 5 of the tubular body 2.

[0092] This pipette tip 1 has no shoulder between the middle portion and the head portion.

[0093] The flange 31 has on the underside downwardly projecting ribs 32 that extend radially outward starting from the head portion 9.

[0094] The flattened areas 12 extend starting from the underside of the flange 31 in the axial direction of the tubular body 2 until the upper edge region of the transition portion 30. This pipette tip 1 also has three planar flattened areas 12. The adjoining regions 13 of the head portion 9 each have in the cross-section a circular profile that extends over the entire region between two adjacent flattened areas 12.

[0095] One or more pipette tips 1 according to FIGS. 6 to 10 can be provided in a holder for pipette tips. In this case, they are inserted into holes of the holder and supported with the ribs 32 on the underside of the flange 31 on the edge of the holes. According to FIG. 10, the attachment 21 is only partially shoved into the pipette tip 1 up to the uppermost guide bead 25. Farther down, the pipette tip 1 has another guide bead 25 and below it has a sealing bead 23. The attachment is shoved forward to the sealing bead 23 so that the pipette tip 1 is aligned and clamped in a sealing manner onto the attachment 21. The guide beads 25 also contribute to sealing the pipette tip 1 on the attachment 21.

[0096] The sealing bead 23 is simultaneously a braking bead, which brakes the insertion of an attachment into the pipette tip 1. The braking effect is determined by the bevel at the upper edge and the rounding on the crest of the sealing bead 23.

LIST OF REFERENCE SIGNS

[0097] 1 Pipette tip [0098] 2 Tubular body [0099] 3 Lower end [0100] 4 Lower opening [0101] 5 Upper end [0102] 6 Upper opening [0103] 7 Beginning portion [0104] 8 Middle portion [0105] 9 Head portion [0106] 10 Shoulder [0107] 11 Outer circumference [0108] 12 Flattened area [0109] 13 Adjoining region [0110] 14 Curved profile [0111] 15 Straight profile [0112] 16 Edge [0113] 17 Inner circumference [0114] 18 Widened area [0115] 19 Insertion bevel [0116] 20 Seating region [0117] 21 Attachment [0118] 22 Sealing structure [0119] 23 Sealing bead [0120] 24 Guide structure [0121] 25 Guide bead [0122] 26 Conical braking region [0123] 27 Central region [0124] 28 Marking [0125] 29 Label [0126] 30 Transition portion [0127] 31 Flange [0128] 32 Rib