FI60359C - pipette - Google Patents

Description

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[3 (11) UTLÄGGNINGSSKRIFT 60359 C Patent granted 11 01 1982 '' Patent neddelat ^ (51) Kv.lk.3 / lnt.ci.3 B 01 L 3/02 FINLAND —FINLAND (21) Patvnttihakamui - PatantanaSkning 801770 (22) ) Hakamltpllvl - Anattknlngadag 02.06.80 ^ ^ (23) AlkuplWt — GHtlghatsdag 02.06.80 (41) Tullut | välla «kal - Bllvlt offancllg

Patent and Registration Office .. _ . ,. .....

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Patent and registration authorities Anaökan utlagd och uthakriftm publkarad 30.09.8l (32) (33) (31) Pyydetty atuoJkaus — Begird prloritet (71) Limited partnership Finnpipette Osmo A. Suovaniemi, Pulttitie 9> OO8IO Helsinki 8l, Finland-Finland (FI) (72) Osmo A. Suovaniemi, Helsinki, Finland-Finland (Fl) (7M Ruska & Co (5 ^) Pipette - Pipett The present invention relates to a pipette comprising a body part of a cylindrical hand-position attached thereto, in the cylinder space of which a piston and the piston is provided with two nested piston rods, each with a knob at its upper end, and the movement of the inner secondary piston rod of said piston rods is longer than prevented from rotating with respect to the handle portion.

In particular, the invention relates to a liquid dispensing pipette, more particularly to its adjustment to different volumes and calibration.

In the pipette according to the invention, its adjustment to different volumes and calibration can be performed using the same adjustment and calibration member. Particularly characteristic of the invention is that the calibration of the pipette can be performed from outside the pipette without opening it and the calibration member moves with it in a member which transmits the movement to the piston or is part of it.

The pipette according to the invention is mainly characterized in that a sleeve-like adjusting device for calibrating the pipette is arranged around the piston rod surrounding the secondary piston rod. from the outside using an adjusting and calibrating element.

By applying the present invention to different types of e.g. , the pipette must be opened.

The invention will become more apparent from the following description and the accompanying drawing, which shows an application example of a pipette according to the invention in a sectional side view.

In the pipette according to Fig. 1, a body part 2 is connected to the preferably cylindrically shaped handle part 1, inside which the piston part 3 passes and to which the tip of the pipette acting as a liquid container * 4 can be connected. The sealing between the body part 2 and the piston 3 takes place by means of an O-ring 5, which is pressed against the 0-ring support 6 by a coil spring 7. flange 11. The piston rod 8 is threadedly connected to a control device 12 which rests via shoulders on a support and scale part 13 connected to the handle part 1.

Inside the handle part 1 there are conductors 14 which slide on the arm 8 in guides 15 along the longitudinal axis.

When pipetting with the pipette according to Fig. 1, the knob 16 at the top of the piston rod 8 is pressed, which transmits the movement through the piston rod 8 and the adjusting member 10 therein to the piston 3 by means of a flange 11. In the filling step of the pipette tip 4, the knob 16 is pressed to its lower position a distance a and then, while the pipette tip 4 is in the liquid, the piston 3 is allowed to rise to its upper position by a distance a. When the pipette tip H is emptied, the knob 17 of the secondary piston rod 9 is pressed, whereby the secondary piston rod 9 travels down a total of a and b. This combined movement (a + b) is transmitted through the control member 10 to the piston 3 via the flange 11, whereby the discharge movement of the piston 3 is longer than its filling movement and which in turn ensures a good emptying of the pipette tip 4 from the liquid to be pipetted.

The following are some of the features and advantages of the present invention.

The pipette can be calibrated to a certain volume at the manufacturing stage by an adjusting device 12 operated from outside the pipette and connected to a movable piston rod 8. In addition, the distance traveled by the secondary piston rod 9 inside the piston rod 8 can be adjusted by means of an adjusting member 10.

When adjusted by the adjusting device 12 by turning it either clockwise or counterclockwise, the rotation of the piston rod 8 with it is prevented by means of the guides 14 and the guides 15. These members also prevent the piston rod 8 from rotating during pipetting.

Scales can be connected to the control device 12 and the scale part 13 to facilitate calibration and / or to indicate a certain volume. Such scales may, if necessary, be marked to indicate a certain volume and / or a certain mass for liquids of different specific gravity. Ko. the scales can also be used to adjust the desired volume of the pipette over a certain volume range.

The invention presented here is also applicable to the so-called reverse pipetting method, in which more liquid is taken into the pipette tip than it is removed (Medical Laboratory Technology, 31, 213> 197 * 0- In this case, the filling step of the pipette tip * 1 takes place by first pressing the secondary knob 17 to its lower position, the plunger 3 going down and b and then liquid is sucked into the pipette tip 4 by allowing the plunger 3 to travel to its upper position a + b. In the step of emptying the pipette tip 4, the knob 16 is pushed down to the plunger 3 and the plunger 3 travels down the distance a. In many cases, the reverse pipetting method improves pipetting accuracy and reproducibility.