EP3115110B1 - Pipette tip - Google Patents

Description

The invention relates to a pipette tip.

Pipette tips are used with pipettes and other dosing devices to dose liquids. Hereinafter, pipettes and other metering devices are collectively referred to as "pipetting devices". Pipette tips have an elongate, tubular body having at the lower end a lower opening for the passage of liquid and at the upper end an upper opening for clamping onto the neck of a pipetting device. Known are standardized conical or frusto-conical approaches with a standard geometry, which is used by many manufacturers uniformly and which is characterized for each pipette tip size by a specific mean diameter and by a specific cone angle of the conical approach. Also known are approaches that have two circumferential rings or beads that are rigid or designed as elastic sealing rings. These approaches are used in dosing machines in particular. They are often dimensioned so that pipette tips can be clamped on them, which are dimensioned for clamping on the standardized conical approaches.

Pipetting devices have a gas displacement device, which is usually a cylinder with a piston axially displaceable therein. The gas displacement device is connected to a through hole of the neck. The pipette tip is clamped by pressing the approach of the pipetting device in the upper opening of the pipette tip sealingly on the approach.

By means of the gas displacement device, an air column is displaced to suck liquid in the seated on the approach pipette tip or from to launch this. If the air column is displaced upwards, a certain amount of liquid is sucked through the lower opening in the pipette tip. By moving the air column down a quantity of liquid is discharged through the lower opening from the pipette tip.

Pipetting devices usually have an ejector, which acts on the upper edge of the pipette tip to squeeze them from the approach. This avoids the user having to touch the contaminated pipette tip to wipe it off the neck.

The pipetting device may be a handheld pipette that the user can hold and manipulate with one hand. It can also be a metering station or a work station (work station) to be integrated. In all cases, the gas displacement device may be manual or motor driven. The attachment and ejection of the pipette tip can also be done manually or motor driven.

To avoid incorrect pipetting, the pipette tip must be sealingly fixed on the shoulder. In addition, the forces for attaching and dropping the pipette tip from the neck should not be too high. In conventional pipette tips, the contact area with the conical shoulder is frusto-conical. When attaching the pipette tips are widened elastically on the circumference by the approach. The spring characteristic is steep, so high Aufsteckkräfte are applied. After fitting, a correspondingly high static friction acts between the attachment and the pipette tip. This static friction must be overcome when the pipette tip is dropped. The user is burdened by the high forces for attaching and dropping the pipette tip.

As far as the plugging and dropping by means of motor drives, they must be correspondingly powerful and have a high power consumption.

The US 4,748,859 describes a pipette tip having three inner coaxial annular sealing bands axially spaced from an upper opening to receive a conical projection. The first two sealing bands and adjacent recessed areas of the pipette tip are relatively compliant and shaped so that the two sealing bands simultaneously engage, guide and laterally support the approach of the pipette as the projection penetrates into the pipette tip to provide annular sealing areas between the pipette tip and shaft form. The third sealing band is relatively stiff and forms a third annular, liquid-impermeable sealing area and a controllable stop for the hub so that the pipette tip is located on the hub adjacent the pipette tip ejector mechanism. The first and the second sealing band and the upper edge of the third sealing band are arranged on a cone with the same geometry as the approach. The stop is caused by an increased wall thickness of the pipette tip in the region of the third sealing strip. A disadvantage is the weak expression of the stop, so that the Aufsteckkraft can be increased almost arbitrarily and a correspondingly high discharge force must be applied.

The US 6,197,259 B1 describes a pipette tip that can be readily and firmly mounted on a neck of a pipette and easily dropped from it by the use of relatively low axial pin and drop forces of six and three pounds (26.7 and 13.3 N, respectively). The pipette tip has a tubular pipette section which has a conical upper end with an inner diameter at the upper end that is larger than the diameter of the lip of the pipette onto which the pipette tip is to be mounted. Furthermore, the pipette tip has a hollow central portion and an annular sealing portion at the junction between the upper end and the central portion. The annular sealing area has an inner diameter smaller than a value "x" and is designed to engage the lower end of a seal zone of the lug to be radially expanded when the lug is inserted. As a result, a liquid-tight seal between the sealing zone of the approach and the sealing region of the pipette tip is generated. Further, the pipette tip on the inside adjacent to the sealing region has lateral stabilizing means which engage the outer surface of the neck to stabilize the pipette tip on the neck. These lateral stabilizing means comprise at least three circumferentially spaced contacts extending inwardly from the inner surface of the pipette tip. The diametrical spacing of the contacts is sized to easily engage the free end of the lug and allow the lower end of the lug to slip past without flaring the side walls in the pipette tip on which the contacts are located. The contacts provide lateral support for the pipette tip on the neck to prevent the pipette tip from lateral movement when external forces act on the pipette tip from outside, such as when dispensing liquid to a wall. As the lower end of the seal zone of the lug engages the seal area of the pipette tip, the pipette tip is stretched in the seal area and immediately adjacent thereto. As the contacts guide the pipette tip onto the lug and align it stably and securely with the lug, the sidewall of the pipette tip deforms inwardly between the contacts and does not expand, thereby minimizing the force required to depress the lug. The approach can be pressed deep into the pipette tip with increasing attachment force. Correspondingly high ejection forces are required for the release of the pipette tip Approach to apply. In addition, this construction is due to the small, inwardly projecting contacts only for relatively large pipette tips. With smaller pipette tips, the contacts can no longer be realized.

The EP 2 606 977 A1 describes a pipette tip having the shape of an elongate tube with a lower opening at the lower end for the passage of liquid and an upper opening at the upper end, wherein adjacent to the upper opening on the inner periphery there is a seating area which is adapted for attachment to a standardized one conical approach of a pipetting device is used. The seating area has a holding area with radially inwardly projecting, axially extending ribs and below the holding area a sealing area. The seating area is such that when the pipette tip is fitted to the seating with a seating force to hold and seal the pipette tip onto the neck, the ribs are partially plastically deformed and elastic deformation occurs outside the ribs in the seating area. In the sealing region, the pipette tip has a peripheral, inwardly projecting sealing projection. Under the sealing area, it has a conically widening to the upper opening towards braking area for limiting the Aufsteckens. In this pipette tip, a secure seal on the approach of a pipetting device is ensured and the ejection force to be applied for ejecting substantially reduced. This design is also particularly suitable for relatively large pipette tips with 2.5, 5.0 and 10 ml nominal volume. For smaller pipette tips, it is less well suited due to the difficult production of filigree ribs.

The US 2002/0094302 A1 describes a pipette tip with two spaced apart in the axial direction of each sealing rings next to a Rezsess on the inner circumference of a conical receptacle for the conical approach of a pipette. When inserting the approach of the pipette in the recording both sealing rings bent and flattened in the distal direction to produce a liquid-tight seal.

The US 3,732,734 describes a pipette tip having a receptacle for a conical neck of a pipette on the inner circumference. On the inner periphery of the approach, a plurality of annular ribs are successively arranged, wherein the inner diameter of the successive ribs decreases into the interior of the pipette tip inside. When the tapered projection is inserted into the receptacle, it comes into contact with the annular fins one after the other, thereby compressing them and establishing a mechanical connection and an airtight seal between the pipette tip and the shoulder.

Based on this, the present invention seeks to provide a pipette tip, the good sealing and safe on the approach of a pipetting device clamped, can be thrown off the approach with reduced effort and is also well suited for smaller pipette tip sizes.

The object is achieved by a pipette tip having the features of claim 1. Advantageous embodiments of the pipette tip are specified in subclaims.

The pipette tip of the present invention has a tubular body having a lower opening at the lower end for passage of liquid and an upper opening at the upper end, the body having, adjacent to the upper opening, a seating area for attachment to a conical neck of a pipetting device located at Inner circumference of the tubular body at a distance from the upper opening a circumferential, inwardly projecting sealing projection, below the sealing projection has a circumferential, downwardly stronger than the neck tapered braking area and above the sealing projection has a circumferential, inwardly projecting support projection and is formed in that the sealing projection can be clamped sealingly onto the projection with elastic deformation, wherein the braking region bears further down on the projection and the supporting projection rests further up against the projection without pretension or by a circumferential gap from the Ans atz, and wherein the lug (29) has a mean diameter and a cone angle according to one of the following combinations: Average diameter cone angle 14.3 mm 4.35 ° 12.4 mm 4.00 ° 9.3 mm 3.78 ° 7.1 mm 2.71 ° 7.1 mm 2.48 ° 4.4 mm 6.99 ° 3.3 mm 6.68 ° 2.95 mm 4.77 °

When attaching the pipette tip according to the invention to a conical projection of a pipetting device, the surface pressure in the region of the sealing projection causes an elastic deformation of the sealing projection. By a suitable geometry of the sealing projection, a small wall thickness of the pipette tip next to the region of the sealing projection and the material of the pipette tip can have a relatively flat spring characteristic for the elastic deformation the sealing projection can be achieved. As a result, the Aufsteckkraft increases relatively gently with the Aufsteckweg. For this purpose, according to a preferred embodiment of the pipette tip, the seating area has an upper area which circulates between the sealing projection and the supporting projection on the inner circumference of the tubular body, and / or a lower area which circulates between the sealing projection and the braking area on the inner circumference of the tubular body, and the seating area is such designed such that the upper portion and / or the lower portion, with less elastic deformation than the sealing projection or not at the neck rests when the pipette tip is sealingly clamped on the approach.

The attachment of the pipette tip on the approach is limited by the gradually downwardly tapered braking area (braking ramp) below the sealing projection. For this purpose, the brake area tapers more than the approach, so that it meets the brake area when entering the seating area. For example, the braking area is conical, with its cone angle is greater than the cone angle of the approach. As a result, the Aufsteckweg is limited. The effective between the pipette tip and approach and to be overcome during ejection frictional force between the pipette tip and approach is limited thereby. The geometry of the brake area, the wall thickness of the pipette tip in its area and the material of the pipette tip can be selected so that the brake area is deformed when the approach of the approach, so that the Aufsteckbewegung is stopped gradually and not abruptly. The gentle stopping of the attachment movement has a gentle effect on the joints. In addition, the user has the opportunity to improve the tight fit of the pipette tip on the approach by pressing the pipette with the approach in the pipette tip. A rigid stop does not offer this possibility. Preferably, in this case, the braking area is plastically deformed, so that the ejection force is only slightly increased by its deformation. The The invention relates to possible embodiments with an elastically or elastically and plastically deformable braking region. The frictional force acting between the pipette tip and the projection and to be overcome during ejection increases only slightly when the braking region is elastically deformed.

The pipette tip held with relatively low frictional force at the neck must not tilt or become detached from the attachment during pipetting, especially if lateral force is exerted on the pipette tip when the sample is delivered to a wall. For trapping lateral forces, the pipette tip has a circumferential support projection on top. The support projection is without bias on the approach or is spaced by a circumferential gap from the approach, so they do not increase the frictional forces between the pipette tip and approach and thus the Abwerfkräfte applied. Due to the fact that the supporting projection bears on the projection without bias or is separated by a gap from the projection, frictional forces between the supporting projection and the projection are avoided. However, a tilting of the pipette tip on the approach is prevented by the support projection. If the support projection is spaced by a gap from the approach, the gap is dimensioned so small that the pipette tip bridges the gap by elastic deformation and rests against the support projection, without their fixation on the sealing projection and the brake area dissolves. Owing to the geometry of the sealing projection, the braking region and the supporting projection, pipette tips according to the invention can be produced well even with relatively small pipette tip sizes, in particular less than 2.5 ml. However, the invention is also suitable for the production of relatively large pipette tips.

Thus, according to the invention, a pipette tip suitable for both large and small pipette tip sizes is achieved, which securely seals and protected against tilting by laterally acting forces on a neck fixable and with relatively little effort from the approach is solvable. The user can easily apply the required attachment force by means of his forearm and hand. The low release force relieves the user of a hand-held pipette with an ejector that can be operated by means of the thumb. Likewise, motor-displaced pipetting devices and motor-driven ejectors are relieved by the pipette tip according to the invention.

Furthermore, the object is achieved by a pipette tip with the following features:
The pipette tip of the present invention has a tubular body having a lower opening at the lower end for passage of liquid and an upper opening at the upper end, the body having, adjacent to the upper opening, a seating area for attachment to a conical neck of a pipetting device located at inner circumference of the tubular body at a distance from the upper opening a circumferential, inwardly projecting sealing projection, below the sealing projection has a circumferential, downwardly stronger than the neck tapered braking region and above the sealing projection has a circumferential, inwardly projecting support projection and so formed in that the sealing projection and the braking portion are cut by the lateral surface of an imaginary cone whose axis coincides with the central axis of the tubular body, and the supporting projection on the outside of the lateral surface of the geda cust cone is located or outside the outside of the lateral surface of the imaginary cone is arranged. Here, the imaginary cone to which the design of the seating area refers to the conical approach to which the pipette tip is sealingly clamped. According to a preferred embodiment, the seating area has a upper portion which circulates between the sealing projection and the support projection on the inner circumference of the tubular body and which abuts on the outer side of the lateral surface of the imaginary cone or outside the outside of the lateral surface of the imaginary cone is arranged. According to a further embodiment, the seating area has a lower area which circulates between the supporting projection and the braking area on the inner circumference of the tubular body and rests on the outer side of the lateral surface of the imaginary cone or outside the outer surface of the lateral surface of the imaginary cone. The upper portion and the lower portion cause a relatively flat spring characteristic for the elastic deformation of the sealing projection. Preferably, this is an upper recess and / or a lower recess on the inner circumference of the tubular body.

The above pipette tip has according to an advantageous embodiment, the features of the pipette tip according to at least one of claims 1 to 13.

The pipette tip according to the invention is suitable for conical approaches of any dimensions. Preferably, the pipette tip according to the invention is designed for connection to a standardized conical approach. Here, the pipette tip is formed so that the sealing projection is clamped under elastic bias sealingly on the approach, wherein the braking area abuts the neck and the support projection bears without bias at the neck or is spaced by a circumferential gap from the neck when the conical approach a middle Diameter and a cone angle according to one of the following combinations: Pipette tips size (in microliters) Average diameter cone angle 1000-10000 14.3 mm 4.35 ° 100 - 5,000 12.4 mm 4.00 ° 500 - 2,500 9.3 mm 3.78 ° 50 - 1,000 7.1 mm 2.71 ° 50 - 1,250 7.1 mm 2.48 ° 20-30 or 2-20 4.4 mm 6.99 ° 0,5 - 20 3.3 mm 6.68 ° 0.1-20 or 0.1-10 2.95 mm 4.77 °

Here, the average diameter and the cone angle dimensions of a conical seat surface of the approach for attaching a pipette tip.

According to a further embodiment of the invention, the pipette tip, which is designed for a projection with one of the above combinations of medium diameter and cone angle, has a pipette tip size specified for this combination in the above table.

According to a further embodiment, a tolerance of +/- 7% applies to the diameter data in the above table.

According to an alternative embodiment to the above embodiment applies to the diameter data in the above table, a tolerance of +/- 0.14 mm and / or for the angle specifications, a tolerance of +/- 0.6 °.

According to a further embodiment, a tolerance of +/- 0.05 mm applies to the diameter data in the above table and / or a tolerance of +/- 0.3 ° for the angle data in the above table.

According to one embodiment, a circumferential lower recess is provided on the inner circumference of the tubular body between the sealing projection and the brake region, and / or a circumferential upper recess is provided on the inner circumference of the tubular body between the sealing projection and the supporting projection. Through the lower recess and / or the upper recess, the wall thickness is reduced. As a result, the elastic deformability of the sealing bead is promoted with a relatively flat spring characteristic. The upper recess and / or the lower recess is not at the neck when the pipette tip is sealingly clamped on the approach. The upper recess is a specific embodiment of the above-mentioned upper portion of the seating area, and the lower recess is a specific embodiment of the above-mentioned lower portion of the seat portion.

The relatively large wall thickness in the region of the support projection is advantageous for the rigidity of the support projection and the lateral support of the pipette tip.

When manufacturing the pipette tip by injection molding, it is preferable to design and dimension the lower recess and / or the upper recess such that an allowable forced removal of the pipette tip from a core for molding the inner contour of the pipette tip is possible. Under this condition, a reduction of the material volume in the head area of the pipette tip of about 20% can be achieved.

According to a further embodiment, the lower recess and / or the upper recess in a longitudinal section through the body has a rounded contour. The rounded contour also favors the elastic deformability of the sealing projection. Further, it is advantageous for injection molding by fostering the stripping of pipette tips from needle cores to form the inner contour of the pipette tips.

To improve the elastic deformability of the sealing projection and the production of the pipette tips by injection molding, the contour of the lower recess smoothly passes in a longitudinal section through the body in the contour of the braking area and / or the sealing projection and / or goes over the contour of the upper Recess in a longitudinal section through the body smoothly into the contour of the sealing projection and / or the support projection over. The smooth transition from the upper recess to the support projection is also advantageous for the rigidity of the support projection.

According to a further embodiment, the sealing projection and / or the supporting projection in a longitudinal section through the body in each case the contour of a wave crest and / or has the lower recess and / or the upper recess in a longitudinal section through the body in each case the contour of a wave trough.

According to a preferred variant of the invention, the support projection is designed and dimensioned so that it just rests against the projection or is spaced by a gap from the approach, if the approach to the system at the brake area, if necessary, with a small deformation of the braking area in the pipette tip is used. This ensures that the support projection rests without bias on the approach. According to an alternative variant of the invention, the support projection is designed and dimensioned so that it is plastically deformed when the approach is applied to the brake area. In this case, the plastic deformation of the support projection can compensate for a different depression of the approach in the pipette tip under different deformation of the braking area. Also in this embodiment, the support projection is due to the plastic deformation without bias on the approach.

According to a further embodiment, the sealing projection, braking region and supporting projection are formed such that the sealing projection can be clamped sealingly onto the projection with elastic deformation, wherein the braking region bears further down on the projection and the supporting projection by a circumferential gap with a gap width of not more than 0.2 mm , preferably a maximum of 0.15 mm, preferably a maximum of 0.1 mm, preferably a maximum of 0.08 mm is spaced from the approach.

According to a further embodiment, the pipette tip has an upwardly widening insertion region above the support projection. The insertion area facilitates the insertion of the approach into the pipette tip.

According to a further embodiment, the insertion region smoothly merges into the support projection. This promotes a stiff support projection, which supports the pipette tip laterally stable on the approach.

According to a further embodiment, the pipette tip has a larger outside diameter than below in a head section extending from the upper opening to the braking area. The head section serves to hold the pipette tip on a support. He also contributes to the stiffening of the seating area in the region of the support projection.

According to a further embodiment, the pipette tip at the bottom of the head region on the outside a paragraph for supporting on a support.

According to a further embodiment, the pipette tip is made of a plastic. This is advantageous for the execution as a disposable part. According to one preferred embodiment, the pipette tip is made in one piece from a plastic.

According to another embodiment, the pipette tip is made of a polyolefin, preferably polypropylene or polyethylene.

According to a further embodiment, the pipette tip is translucent, preferably transparent. Further preferably, the pipette tip is made by injection molding.

Preferably, the inner and / or outer diameter of the pipette tip increases from the lower opening to the upper opening.

Furthermore, the object is achieved by a system having the features of claim 14.

In the pipette tip and pipetting device system of the present invention, the pipette tip has a tubular body having a lower opening at the lower end for passage of liquid and an upper opening at the upper end, the body having a seating area adjacent to the upper opening for fitting to a conical one Approach of a pipetting device, which at the inner periphery of the tubular body at a distance from the upper opening a circumferential, inwardly projecting sealing projection, below the sealing protrusion a circumferential, stronger than the neck tapered braking area and above the sealing projection a circumferential, inwardly projecting Support projection, the pipetting device has at least one conical approach for attaching the pipette tip, which has a hole at the lower end of the neck with a displacement device for air in the Pipettiervorrichtung is connected, wherein the seating area is formed so that the sealing projection with elastic deformation sealingly clamped onto the approach, the brake area is applied further down the approach and the support projection rests without bias on the approach or spaced by a circumferential gap from the approach and wherein the projection (29) has a mean diameter and a cone angle according to one of the following combinations: Average diameter cone angle 14.3 mm 4.35 ° 12.4 mm 4.00 ° 9.3 mm 3.78 ° 7.1 mm 2.71 ° 7.1 mm 2.48 ° 4.4 mm 6.99 ° 3.3 mm 6.68 ° 2.95 mm 4.77 °

Advantageous embodiments of the system according to the invention have a pipette tip according to at least one of the embodiments described above.

Fig. 1a-e

eine Pipettenspitze in Seitenansicht (Fig. 1a), in einem Längsschnitt (Fig. 1b), in vergrößerter Unteransicht (Fig. 1c), in vergrößerter Draufsicht (Fig. 1d) und in einem vergrößerten Längsschnitt durch den Sitzbereich (Fig. le);

Fig. 2

eine Pipette mit Ansatz beim Aufstecken der Pipettenspitze von Fig. 1 in einer grobschematischen Seitenansicht;

Fig. 3

die Pipettenspitze von Fig. 1 aufgeklemmt auf den Ansatz der Pipette in einem vergrößerten Längsschnitt;

Fig. 4

der Sitzbereich der Pipettenspitze aufgeklemmt auf den Ansatz in einem vergrößerten Längsschnitt;

Fig. 5

der Sitzbereich in unverformtem Zustand und mit verformtem Dichtvorsprung in einem Längsschnitt;

Fig. 6a+b

mittlerer Durchmesser und Konuswinkel standardisierter konischer Ansätze zum Aufstecken von Pipettenspitzen verschiedener Größen in einer Übersicht.

The invention will be explained in more detail with reference to the accompanying drawings of an embodiment. In the drawings show:

Fig. 1a-e

a pipette tip in side view ( Fig. 1a ), in a longitudinal section ( Fig. 1b ), in an enlarged bottom view ( Fig. 1c ) in enlarged plan view ( Fig. 1d ) and in an enlarged longitudinal section through the seating area (Fig le);

Fig. 2

a pipette with approach when attaching the pipette tip of Fig. 1 in a rough schematic side view;

Fig. 3

the pipette tip of Fig. 1 clamped on the approach of the pipette in an enlarged longitudinal section;

Fig. 4

the seating area of the pipette tip clamped on the approach in an enlarged longitudinal section;

Fig. 5

the seating area in undeformed state and with deformed sealing projection in a longitudinal section;

Fig. 6a + b

average diameter and cone angle of standardized conical approaches for attaching pipette tips of various sizes in an overview.

In the present application, the terms "top" and derived therefrom, such as "above" and "below", refer to the orientation of a pipette tip during pipetting, in which the pipette tip is vertically aligned and the lower openings are at the bottom and the upper opening at the top ,

According to Fig. 1 For example, a pipette tip 1 has an elongate, tubular body 2 which has a lower opening 4 at the lower end 3 and an upper opening 6 at the upper end 5. The lower opening 4 is smaller than the upper opening 6.

Generally, the inner and / or outer diameter of the tubular body 2 increases from the lower opening 4 toward the upper opening 6. In the example, the tubular body 2 at the bottom has a conical starting portion 7, above a middle portion 8 with a smaller cone angle than the starting portion 7 and above a head portion 9 with larger outer dimensions than the central portion 8. At the bottom of the head portion 9 runs outwardly with respect to the central portion 8 outward paragraph 10 um. The paragraph 10 serves to support on the edge of a hole of a wearer.

The head portion 9 has at the bottom a first frustoconical or cylindrical head portion 11 with the shoulder 10 at the bottom. The first frusto-conical head part can expand upwards or downwards. At the top, the first frusto-conical or cylindrical head part 11 is connected to an upwardly flared, second frusto-conical head part 12 of the head section 9. The second frusto-conical head part 12 has on the outside of the circumference a series of teardrop-shaped, outwardly projecting profiles 13.

Adjacent to the shoulder 10, the middle section 8 has a short transition area 14 with a larger cone angle on the outside than the arranged underneath main part of the central portion 8. The transition region 14 is connected by a radius to the main part of the central portion 8.

Outside the circumference of the central portion 8 sit graduation rings 15, next to which numbers 16 are arranged, which indicate the level in milliliters.

At a distance from the upper opening 6 runs at the inner periphery of the body 2 within the head portion 9, a radially inwardly projecting sealing projection 16 (sealing bead) in the form of a bead. At a further distance from the upper opening 6 runs on the inner circumference of the body to an upwardly widening braking area 17 (brake ramp) to. The braking region 17 extends from a lower edge region of the head section 9 up to an upper edge region of the middle section 8.

Above the sealing projection 16, at the inner circumference of the body 2, an inwardly projecting support projection 18 (support rib) in the form of a bead passes.

Between the sealing projection 16 and the braking portion 17 is a circumferential, rounded lower recess 19 is present.

Between the sealing projection 16 and the support projection 18 is a rounded upper recess 20 is present. The lower recess 19 smoothly merges into the sealing projection 16 at the top and smoothly into the braking region 17 at the bottom. The upper recess 20 smoothly merges into the sealing projection 16 and smoothly into the support projection 19 at the top.

At the top of the support projection 18, an upwardly widening insertion region 21 connects. The insertion region 21 is conical at the top and goes smoothly down into the support projection 18.

The sealing projection 16, brake area 17, support projection 18 and lower recess 19 and upper recess 20 comprising part of the pipette tip 1 is a seating area 22, which serves to releasably hold the pipette tip 1 at a neck of a pipette.

In a longitudinal section through the body 2 thus has the inner contour of the pipette tip 1 from the braking area 17 to the support projection 18 a wave-shaped course, braking area 17, sealing projection 16 and support projection 18 peaks and the lower recess 19 and the upper recess 20 wave troughs.

The seating area 22 thus has its lowest wall thicknesses in the region of the wave troughs below and above the sealing projection 16. He has the greatest wall thicknesses on the sealing projection 16, support projection 18 and brake area 17.

According to Fig. 2 For example, a hand-held pipette 23 has a housing 24 in the form of a handle, which contains a displacement device 25 for displacing air and to which an actuating element 26 for actuating the displacement device 25 and an ejector 27 with an associated further actuating element 28 are arranged. At the bottom, a standardized conical projection 29 is arranged on the housing 24. A pipette tip 1 can be attached to the projection 29.

According to Fig. 3 and 4 are on insertion of the pipette tip 1 with the seat portion 22 on the projection 29 of the sealing projection 16 elastically deformed.

Due to the wave troughs 19, 20, the elasticity in the region of the sealing projection 16 is greater and the spring characteristic of the deformation of the sealing region is flatter than in conventional pipette tips. As a result, the Aufsteckkraft and ejection force is reduced.

The lower end of the lug 29 abuts on the braking area 17, whereby a stop is effected. The Aufsteckbewegung can be braked by the braking area 17 by this is deformed. Preferably, the braking area 17 is plastically deformed, so that the release force is not significantly increased by the braking area 17. The inclination of the braking area 17 reduces the frictional forces between the shoulder 29 and the braking area 17 anyway.

The support projection 18 is matched to the projection 29, that it bears against the projection 29 without bias, or is spaced therefrom by a small gap. In the example, there is a circumferential gap 30 with a gap width of 0.08 mm. The support projection 18 prevents tilting of the pipette tip 1 on the projection 29, without increasing Aufsteckkraft and ejection force. The support projection 18 is relatively stiff due to its relatively large wall thickness, so that it does not yield when tilted the pipette tip 1.

The invention includes possible embodiments in which the support projection 18 is plastically deformed by insertion of the lug 29. Due to the plastic deformation of the support projection 18 as it were without bias on the lug 29 so that it does not increase the release force. By the system of the support projection 18 on the lug 29 tilting is particularly effectively prevented.

The elastic deformation of the sealing projection 16 by insertion of the projection 29 is in Fig. 5 illustrated. The additional registered inner contour within the Wall thickness of the head region 9 illustrates the elastic deformation of the sealing projection 16.

Fig. 6a . b each show the mean diameter and the cone angle of a standardized conical projection 29 over an associated pipette tip 1 with a certain tip size. The mean diameter is given in millimeters and the cone angle in degrees. As a measure of the pipette tip size, in each case the area of the filling volume in microliters or milliliters is indicated, with which the pipette tip 1 can be filled. The mean diameter of the lug 29 refers to a diameter between the lower and the upper end of the lug 29. It need not necessarily be a diameter which is located exactly in the middle between the lower and the upper end of the lug. However, the average diameter may also fall exactly in the middle between the lower end and the upper end of the lug 29. According to one embodiment of the invention, it falls exactly in the middle between the lower end and the upper end of the projection 29th

Additionally are in Fig. 6a . b the tolerances are given for the mean diameter (+/- 0.05 mm) and for the angle data (+/- 0.3 °). The lugs 29 are manufactured with appropriate tolerances.

LIST OF REFERENCE NUMBERS

1

pipette tip

2

body

3

lower end

4

lower opening

5

top end

6

upper opening

7

initial section

8th

midsection

9

header

10

paragraph

11

first frusto-conical or cylindrical head part

12

second frustoconical headboard

13

profiles

14

Transition area

15

Graduierungsring

16

digits

17

braking range

18

supporting projection

19

deepening

20

deepening

21

insertion

22

sitting area

23

hand pipette

24

casing

25

displacement section

26

actuator

27

ejector

28

actuator

29

approach

30

gap

Claims (15)

1. A pipette tip with a tubule-shaped body (2) with a lower opening (4) on the lower end for the passage of liquid and an upper opening (6) on the upper end, wherein the body (2) next to the upper opening (6) has a seating area (22) for mounting on a conical appendage (29) of a pipetting device, which has on the inner circumference of the tubule-shaped body (2) at a distance from the upper opening a circumferential, inwards-protruding sealing projection (16), below the sealing projection (16) a circumferential brake area (17) tapering downwards stronger than the appendage (29) and above the sealing projection (16) a circumferential inwards-protruding support projection (18) and is designed such that the sealing projection (16) under elastic deformation can be clamped in a sealing manner on the appendage (29), wherein the brake area (17) abuts against the appendage (29) further down, characterized in that the support projection (18) abuts against the appendage (29) further above without pretension or is spaced from the appendage (28) by a circumferential gap (30), if the appendage (29) has an average diameter and a cone angle according to one of the following combinations: Average Diameter Cone Angle 14.3 mm 4.35° 12.4 mm 4.00° 9.3 mm 3.78° 7.1 mm 2.71° 7.1 mm 2.48° 4.4 mm 6.99° 3.3 mm 6.68° 2.95 mm 4.77°
2. The pipette tip according to claim 1, in which a circumferential lower recess (19) is present on the inner circumference of the tubule-shaped body (2) between the sealing projection (16) and the brake area (17) and/or in which a circumferential upper recess (20) is present on the inner circumference of the tubule-shaped body (2) between the sealing projection (16) and the support projection (18).
3. The pipette tip according to claim 2, in which the lower recess (19) and/or the upper recess (20) in a longitudinal cut through the body (2) has a rounded contour.
4. The pipette tip according to claim 2 or 3, in which the contour of the lower recess (19) in a longitudinal cut through the body (2) passes smoothly into the contour of the brake area (17) and/or the sealing projection (16) and/or in which the contour of the upper recess (20) in a longitudinal cut through the body (2) passes smoothly into the contour of the sealing projection (16) and/or of the support projection (18).
5. The pipette tip according to one of claims1 to 4, in which the sealing projection (16) and/or the support projection (18) in a longitudinal cut through the body (2) each have the contour of a wave crest and/or in which the lower recess (19) and/or the upper recess (20) in a longitudinal cut through the body (2) each have the contour of a wave trough.
6. The pipette tip according to one of claims 1 to 5, which, in the area of the lower recess (19) and/or the upper recess (20) has a smaller wall thickness than in the area of the sealing projection (16) and/or the support projection (18) and/or the brake area (17).
7. The pipette tip according to one of claims 1 to 6, in which sealing projection (16), brake area (17) and support projection (18) are designed such that the sealing projection (16) under elastic deformation can be clamped in a sealing manner on the appendage (29), wherein the brake area (17) abuts against the appendage (19) further downwards and the support projection (18) is distanced from the appendage (19) by a circumferential gap with a gap width of a maximum of 0.2 mm, preferably a maximum of 0.15 mm, preferably a maximum of 0.1 mm, preferably a maximum of 0.08 mm.
8. The pipette tip according to one of claims 1 to 7, which has an upwards expanding insertion area (21) above the support projection (18).
9. The pipette tip according to claim 8, in which the insertion area (21) passes smoothly into the support projection (18).
10. The pipette tip according to one of claims 1 to 9, which has in a head section (22) extending from the upper opening (6) up to the brake area (17) a larger diameter on the outside than below it.
11. The pipette tip according to claim 10, which has on the lower edge of the head section (22) a ledge (23) on the outside for being supported on a carrier.
12. The pipette tip according to one of claims 1 to 11, which is made of one piece of plastic.
13. The pipette tip according to one of claims 1 to 12, which is made of a polyolefin, preferably polypropylene or polyethylene.
14. A system comprising a pipette tip (1) and a pipetting device (23), in which the pipette tip (1) has a tubule-shaped body (2) with a lower opening (4) on the lower end (3) for the passage of liquid and an upper opening (6) on the upper end (5), wherein the body (2) next to the upper opening (6) has a seating area (22) for mounting on a conical appendage (29) of a pipetting device (23), which has on the inner circumference of the tubule-shaped body (2) at a distance from the upper opening (6) a circumferential, inwards-protruding sealing projection (16), below the sealing projection (16) a circumferential brake area (17) tapering stronger than the appendage (29) and above the sealing projection (16) a circumferential inwards-protruding support projection (18), the pipetting device (23) has at least one conical appendage (29) for mounting of the pipette tip (1), which is connected with a displacement apparatus (25) for air in the pipetting device (23) via a hole on the lower end of the appendage (29), wherein the seating area (22) is designed such that the sealing projection (16) under elastic deformation can be clamped in a sealing manner on the appendage (29), wherein the brake area (17) abuts against the appendage (29) further down and the support projection (18) abuts against the appendage (29) further above without pretension or is spaced from the appendage (29) by a circumferential gap (30) and wherein the appendage (29) has an average diameter and a cone angle according to one of the following combinations: Average Diameter Cone Angle 14.3 mm 4.35° 12.4 mm 4.00° 9.3 mm 3.78° 7.1 mm 2.71° 7.1 mm 2.48° 4.4 mm 6.99° 3.3 mm 6.68° 2.95 mm 4.77°
15. The system according to claim 14, with a pipette tip according to one of claims 2 to 13.

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