FI57544C - SPETSBEHAOLLARE AVSEDD ATT ANVAENDAS VID DOSERINGSPIPETT - Google Patents

Description

fSSFn [B] (11) ADVERTISING PUBLICATION 57,54 /

Ijp lJ ^; UTLÄGGNINGSSKRIFT 0 '0 ^ ^ (45) 2 1-s u _ r. L υ i 'y 10 J1 .: 10 ^ T ^ (51) Kv.ik.3 / iiit.a.3 B 01 L 3/02 FINLAND —FINLAND (21) Pit * nttlh «k« inu «-Puantamefcnlng 783383 (22) H »k * m)« ptlvl - Ana6knlng * dig 07 · 11 · 78 **** (23) AlkupUvi — Glttighradag 07.11.78 (41) Has become swollen - Bllvlt offmtllg 08.05.80

Patented and patented. N.htiv «toip« is j, kuL | «ll« au „

Patent · och ragistarstyralaan Amttku uttagd och utUkrWtun pubiicurad 30.05.80 (32) (33) (31) Requested utuolkuut — Begird prlorltut (71) Limited partnership Finnpipette Osmo A. Suovaniemi, Pulttitie 9, OO8IO Helsinki 8l, Finland (FI) 72) Jukka Tervamäki, Helsinki, Osmo Antero Suovaniemi, Helsinki,

Aarre Kukka, Helsinki, Suomi-Finland (FI) (7 * 0 Ruska & Co (5¼) Tip container for use with a dispensing pipette -Spetsbehällare avsedd att användas vid doseringspipett • The present invention relates to a disposable pipette tip container, preferably for use with a dispensing pipette, adapted to be connected, for example by friction, to the lower part of the cylinder part of the pipette or its extension and to have a hole at the lowest point of the tip container for suction that the tip container is adapted to allow the air column to be sucked into the lower part of the tip container to rise as an air bubble or air bubbles above the liquid in the tip container between the successive dispensing steps performed by the pipette and when the liquid column lands up to the bottom of the tip tank.

Previously known is a blunt-tipped tip container for use with a pipette, from which liquids can be dispensed in several successive equal doses, so that the pumping movement of the pipette plunger draws air between doses as a bubble or bubbles into the tip container.

2 57544

However, the disadvantage of a blunt-tipped tip container is that the liquid droplets may remain suspended at the blunt end of the tip container during dispensing, causing inaccuracy. Similarly, when aspirating liquid into the tip tank, it V3i sprays upwards into the plunger space of the pipette, which is thus contaminated with e.g. bacterial or radioactive substances and must be washed.

Likewise, when lifting the piston, there may be a disadvantage that the air bubble entering the tip tank does not rise to the surface of the liquid, but slides along the leading bottom to the edge of the tip tank and grips it under the surface tension and cohesive forces of the liquid, thus preventing the liquid from settling to the bottom tank.

The invention according to the present invention has been made to overcome these drawbacks and the invention is mainly characterized in that a short sharp, downwardly conically tapered tip appendix projecting downwards from the bottom is formed in the lower part of the tip container below the bottom part of the tip container, preferably with a correspondingly upwardly tapering aperture.

The invention will become more apparent from the following description and the accompanying drawings, in which Figure 1 is a side view and a semi-sectional view of a multi-plan dispensing pipette of simple construction provided with tip containers according to the present invention; Figure 2 is a side sectional view of one tip container of Figure 1; Fig. 3 shows a sectional and side view of an alternative tip container application to the tip container of Fig. 2, and Fig. 4 shows the joining of the tip containers according to the invention into a strip or matrix.

Figure 1 shows a 4-channel pipette. The handle part 4 includes a casing 10, a calibration nut 11, a secondary support 13, a knob arm 14, a knob 15, a secondary spring 16 which rests against the support 17 of the secondary support in the casing 10. By turning the calibration nut 11 clockwise or counterclockwise, the stroke length α of the knob arm 14 can be adjusted to correspond to a certain volume. The casing 10 of the handle part 4 is fastened by a thread 18 in the body part 1.

The body part 1 has a support plate 21 of the pistons 20 with a stem 22 attached to it.

3,57544

The arm is forced into the upper position by the primary spring 23. The lower plate 24 of the pistons 20 is fixed to the support plate 21. The support springs 25 force the pistons 20 against the support plate 21. The pistons 20 may move somewhat laterally. The force of the support spring 25 of the pistons 20 is dimensioned so as to be greater than the frictional force of the corresponding O-ring 19 of each piston 20. The pistons 20 run in their own cylinder spaces 12. The cylinder space 12 is surrounded by a cylinder liner 26 which extends into the tip cone 2. The O-ring 19 is supported against the end of the cylinder liner 26 by an O-ring support 28 and a support spring 29. The force of the support spring 29 is greater than the frictional force of the piston 20 . The cylinder liners 26 and their extension tip cones 2 are fixed to a support plate 30, which in turn is fixed to the body part 1. The tip cones 2 are airtight tip containers 3 · The tip containers 3 are adapted to be frictionally connected to the tip cones for suction into the tip container 3 and for emptying the tip container 3 from the liquid therein, respectively. According to Fig. 2, a tapered base part 6 is formed gently around the filling and emptying hole 5 of the tip container 3. In this case, under the influence of the base part 6, the tip container 3 appears to be a blunt-tipped, uniformly thick container compared to conventional tapered tip containers.

In the lower part of the tip container 3 below the bottom part 6 of the tip container 3, a short sharp downwardly tapered tip extension 7 protruding downwards from the base part is formed. Inside the tip insert 7 there is a filling and emptying hole 5 of the tip container 3, most preferably an upwardly tapering hole.

The length of the tip insert 3 of the tip container is 1 to 5 mm, preferably 2-3 mm. An upwardly directed, most preferably sharp-edged annular projection 8 is made on the upper surface of the bottom part 6 of the tip container 3 around the tip container filling and emptying hole 5. The annular projection 8 may also have additional protrusions which facilitate the release and rise of air bubbles on the liquid surface.

Of course, the tip insert 7, the hole 5 and the ring projection 8 can also be located eccentrically with respect to the longitudinal axis of the tip container 3.

In the embodiment shown in Fig. 3, the principle of the tip container is otherwise the same as shown above, but the annular projection 3 'of the tip container 3' with its brushes 9 is formed by the bottom part 6 'of the tip container 3' rising upwards towards the tip container filling and emptying hole 5 '.

"57544

The embodiment of Figure 4 shows how the tip containers 3 according to the invention can be joined into a strip or matrix with flexible bases.

The dosing pipette according to Figure 1 operates as follows: The stroke length b of the piston is divided into two parts a and c ns. by means of a secondary spring 16 and a secondary support 13. When the pipette knob 15 is pressed all the way down, the piston 20 moves its entire stroke length b and fills the tip with the liquid taken up. When the knob 15 is pressed up to the secondary tube 16, the piston 20 moves only part of its entire travel length b, e.g. 1/5 or 1/10. Thus, what is essential for the operation of the pipette according to Fig. 1 is that the pipette now described has a primary movement a short and a secondary movement c long, while very conventional pipettes have a primary movement long and a secondary movement short. By repeatedly pressing the plunger 20 of the pipette according to Fig. 1 according to its short primary movement a downwards, the liquid dispensed from the tip 3 of the pipette is obtained in equal doses to different test tubes. Between doses, the pipette plunger 20 is returned to its upper position, whereby the plunger 20 draws air through the tip of the pipette into the tip container 3. In the tip container 3, air rises as a dose bubble to the liquid column surface, forming an extension to the air column already in the container. Thus, after each dose, the liquid returns to the bottom of the tip container 3 and a new dose is ready to be pipetted.

The shape of the tip container 3 is crucial for the operation of the dispensing pipette as described above, since the approximately uniformly thick shape of the container allows air bubbles to rise freely on the surface of the liquid. The tip container of the pipette must therefore be shaped in such a way as to allow air to rise to the surface of the liquid from the container when the piston returns upwards by the primary movement a. When dispensing the liquid, the liquid detaches particularly well from the tapered tip insert 7 without the drops getting stuck to the lower end of the tip container 3 outside it. The hole 5 in the tip attachment 7 is most preferably in the shape of an upwardly expanding cone, whereby it reduces the risk of the liquid spraying when the liquid is sucked.

Further, when dispensing the liquid with the pipetting motion of the pipette, an air bubble is prevented. sliding into the tip container 3 in the tip container according to the invention by a ring 8 surrounding the upper end of the conical hole 5.

Claims (3)

57544 5 A disposable pipette tip container (3), preferably for use with a dispensing pipette, the upper part of which is adapted to be connected, for example by friction, to the lower part (2) of the pipette cylinder part or its extension and has a hole (5) at the bottom and respectively for emptying the tip container (3) of the liquid therein and that a planar or gently conical bottom part (6) is formed in the lower part of the tip container (3) around the filling and emptying hole (5) of the tip container (3) so that the tip container (3) is arranged between the successive dispensing steps with the pipette, allow the air column to be sucked into the lower part of the tip container (3) to rise as an air bubble or air bubbles above the liquid in the tip container (3) and the liquid column descending to the bottom of formed from the bottom part (6) downwards n a protruding short pointed downwardly conically tapering tip insert (7), most preferably with a correspondingly upwardly conically expanding hole (5) · Tip container according to Claim 1, characterized in that the length of the tip insert (7) of the tip container (3) is 1 to 5 mm, preferably 2 to 3 mm. Tip container according to Claim 1, characterized in that an upwardly directed, preferably sharp-edged annular projection (8) is formed on the upper surface of the bottom part (6) of the tip container (3) around the filling and emptying hole (5) of the tip container (3).