WO2010057860A1

WO2010057860A1 - Automated analysis device with an automatic pipetting device and a pipetting needle rinsing station

Info

Publication number: WO2010057860A1
Application number: PCT/EP2009/065251
Authority: WO
Inventors: Roland Schenk
Original assignee: Diasys Technologies S.A.R.L.
Priority date: 2008-11-18
Filing date: 2009-11-16
Publication date: 2010-05-27
Also published as: EP2347268A1; DE102008058064A1; EP2347268B1; CN102216786A; CN102216786B

Abstract

The invention relates to an automatic pipetting device comprising a rinsing station for rinsing the pipetting needle, wherein the rinsing station comprises at least one rinsing bowl which is opened upward, said bowl having a height corresponding to at least a predefined maximum submersion depth of the pipetting needle into a working liquid during an automated pipetting process. The inner circumference of the rinse bowl is larger than the outer circumference of the pipetting needle and a rinsing bowl base and a rinsing bowl drain are located at the lower end of the rinsing bowl. In order to provide a rinse station for rinsing a pipetting needle, said station quickly and efficiently providing an as optimum as possible inner and outer cleaning of a pipetting needle as possible between pipetting processes with little effort and using low amounts of rinsing liquid, according to the invention a rinse station is proposed wherein the hydraulic drainage friction of the rinse bowl drain is selected such that the flow rate of the rinse liquid is greater than the drainage rate (volume per time) of the rinse liquid through the rinse bowl drain at a given flow rate (volume per time) of a specific rinse liquid through the pipetting needle to the rinse bowl.

Description

Automated analyzer with an automatic pipetting device and a pipetting needle rinsing station

The present invention relates to an automatic pipetting device with a rinsing station for rinsing the pipetting needle of the pipetting device, wherein the rinsing station comprises at least one upwardly open rinsing bowl having a height which is at least a predetermined maximum immersion depth (T) of the pipetting needle into a sample rinse. or reagent liquid during an automatic pipetting operation whose inner circumference is larger than the outer circumference of the pipetting needle and which has at its lower end a Spülnapfboden and a Spülnapfboden or immediately above Spülspapfablauf. Moreover, the present invention relates to an automated analysis apparatus having such an automatic pipetting apparatus and a method for rinsing a pipetting needle of such an automatic pipetting apparatus.

In the context of increasing automation in the field of medical and veterinary diagnostics, i.a. Apparatuses for the automated analysis of liquids, so-called analyzers, designed to take the various reagents required for carrying out an analysis from reagent containers and combine them with a sample for the purpose of carrying out the analysis in a reaction vessel. For this purpose, the analyzers often have a carousel in which either receiving areas for reagent containers or receiving areas for sample containers are provided. In special analyzer carousels, both receiving areas for reagent containers and receiving areas for sample containers are provided. Such carousels are usually driven by a drive device provided in the analyzer for performing a rotary movement of the carousel.

The removal of reagent or sample and the transfer into a reaction vessel is usually carried out by an automatic pipetting device. Such an automatic pipetting device usually comprises a pipetting arm, on which a pipetting needle is arranged vertically, which is connected to a pumping unit, with which a liquid can be drawn into the pipette needle and ejected from the pipetting needle again. Such a pipetting arm is generally designed in such a way that the pipetting needle can be moved over a working area with the pipetting arm, in which working area the reagent containers, sample containers and / or reaction vessels (eg cuvettes) are stationarily arranged or by e.g. B. a carousel are temporarily provided and in which the pipette needle can be immersed. There are pivotable pipetting arms, through one end of which runs an axis of rotation about which the other end of the pipetting arm can move in a circular path. Alternatively, there are also pipetting arms, which can be moved both in one direction X and in a direction Y arranged perpendicular thereto on a plane in the working region of the pipetting arm.

Pipetting can be arranged on lifting columns, with which they are adjustable perpendicular to the base of the work area in the working height, for example, to move the pipette needle on the arranged in the work area liquid container and to be able to insert the pipetting needle into selected liquid container from above. As an alternative to the height adjustment via a lifting column, a pipetting arm can also be designed in such a way that the pipetting needle is arranged to be height-adjustable even on the pipetting arm.

Between the individual pipetting processes, it is regularly necessary to clean the pipetting needle of the automatic pipetting device inside and outside. For this purpose, the pipette needle is usually immersed in a rinsing liquid, wherein a certain amount of rinsing liquid is drawn into the pipette needle. Subsequently, the pipette needle is pulled out of the rinsing liquid and emptied through a waste container or a drain and drained or stripped.

Usually, analyzers also include a measuring device for determining a physical or chemical quantity of a reaction mixture prepared in a reaction vessel. The reaction vessel may, for. Example, be a cuvette, which is arranged in the beam path of a arranged in the analyzer photometer or can be introduced.

In addition, analyzers usually include at least one control unit for controlling the movements of the pipetting arm, the pumping unit, the pipetting needle, the lifting column and / or the carousel, and a data processing device for setting up and executing an analysis program and for processing and outputting a measured physical or chemical Size.

The cleaning of a pipette needle from the inside is relatively unproblematic by pumping through a rinsing liquid in the rule. In contrast, the cleaning of a pipetting needle on its outside is sometimes more difficult. Some reagents and samples are relatively viscous and therefore do not readily drip off the pipetting needle. In addition, some substances dissolve poorly in suitable for analyzers rinsing liquids. Still other liquids strongly adhere to the pipetting needle for other reasons and are difficult to remove. Since very sensitive tests are used in the field of medical and veterinary diagnostics, it is imperative to ensure that the pipette needle is cleaned between the two Pipetting operations as effectively as possible. The immersion of a pipetting needle in a rinsing liquid, wherein the rinsing liquid is sucked into the pipette needle, and the subsequent ejection of the rinsing liquid through the pipette needle does not always provide the desired effectiveness in connection with a stripping process in which liquid is stripped from the outside of the pipette needle.

There is therefore a need for a device that can more effectively clean the interior and exterior of a pipetting needle between pipetting operations than is possible with corresponding prior art devices.

It is therefore the object of the present invention to provide an automatic pipetting device with a rinsing station for rinsing the pipette needle, with which the best possible inner and outer cleaning of a pipetting needle between the pipetting processes can be achieved quickly and efficiently with little effort and with low rinsing liquid consumption.

This object is achieved by an automatic pipetting device with a rinsing station of the type mentioned, wherein at a given delivery rate (volume per time) of a certain rinsing liquid through the pipette needle into the rinsing bowl, the hydraulic flow resistance of Spülnapfablaufs is chosen so that the delivery rate of the rinsing liquid greater as the drain rate (volume per time) of the flushing liquid through the Spülnapfablauf is.

The hydraulic drainage resistance is determined by the nature of the inner surface and the geometry, cross-section and length of the Spülnapfablaufs.

Preferably, the cross section Q of the Spülnapfablaufs is selected so that at a given flow rate (volume per time) of a certain rinsing liquid through the pipetting needle into the rinsing bowl and given internal surface, geometry and length of Spülnapfablaufs the delivery rate of the rinsing liquid is greater than the drainage rate ( Volume per time) of the rinse liquid through the Spülnapfablauf.

The delivery rate is preferably from 500 μl / s to 5000 μl / s. The delivery rate is particularly preferably from 1000 μl / s to 3000 μl / s.

Also included in the concept of the invention are those embodiments in which more than one rinsing bowl drain opening is provided in the rinsing bowl floor. In these cases, the preferred characteristics with regard to the hydraulic drainage resistance and inner surface, geometry and length of Spülnapfablaufs apply accordingly for the sum or the entirety of Spülnapfablauföffnungen. Preferably, the at least one rinsing bowl is a hollow cylinder. In alternative embodiments, however, other cross sections of the rinsing bowl may also be advantageous, for example a quadrangular cross section, a hexagonal or an octagonal cross section.

Expediently, the ratio of the inner circumference (UW) of the rinsing bowl to the outer circumference (UP) of the pipette needle is selected such that, given a sufficient total amount of rinsing liquid, the rinsing liquid rises into the area between the outer wall of the pipette needle and the inner wall of the rinsing bowl. If a corresponding amount of rinsing liquid is ejected through the pipetting needle into the rinsing bowl, this not only cleans the pipetting needle from the inside, but also cleans the pipetting needle from the outside.

In a preferred embodiment of the present invention, the ratio UW / UP is in the range of 1.5-5. Most preferably, this ratio is in the range of 2-3. Particularly preferred is a ratio UW / UP of 3.

In a further preferred embodiment, the hydraulic drainage resistance of the Spülnapfablaufs or the ratio UW / UP and Q are chosen so that at a given delivery rate of a certain liquid through the pipetting needle into the Spülnapf and with sufficient total delivery of flushing liquid in the area between the outer wall the pipetting needle and the inner wall of the rinsing bowl in the rinsing fluid turbulent flow occurs.

Conveniently, the ratios are selected so that the turbulent flow along the pipetting needle over the entire predetermined maximum immersion depth (T) is achieved. Even more preferred occurs the turbulent flow with sufficient total flow in the entire rinsing liquid contained in the Spülnapf.

The turbulent flow has the advantage that hereby a greater cleaning effect is achieved than with only laminar flow.

In particularly preferred embodiments, the hydraulic drainage resistance of the Spülnapfablaufs or the ratio UW / UP and Q are chosen so that at a given delivery rate of a certain rinsing liquid in the area between the outer wall of the pipette needle and the inner wall of the Spülnapfs in the rinsing liquid a Reynolds number of at least 2 500 is reached. Preferably, the hydraulic drainage resistance of the Spülnapfablaufs or the ratio UW / UP and Q are chosen so that at a given delivery rate of a certain rinsing liquid in the area between the outer wall of the pipette needle and the inner wall of the Spülnapfs in the rinsing liquid a Reynolds number of at least 100,000 , preferably from at least 200,000, and more preferably at least 250,000. Expediently, the hydraulic outlet resistance of the rinsing bowl outlet or the ratio UW / UP and Q at a given delivery rate of a particular rinsing liquid are selected such that the Reynolds number is reached along the entire predefined maximum submergence depth (T) of the pipette needle. Most preferably, the Reynolds number is achieved throughout the liquid contained in the rinsing cup.

In a preferred embodiment, the outer circumference (UP) of the pipetting needle is 1 mm to 4 mm. Preferably, the outer circumference of the pipetting needle is in the range of 2 mm to 3 mm. When it is referred to in the context of the present invention from the outer periphery (UP) of the pipette needle, it is meant the outer circumference of the pipette needle in the area that is to be cleaned externally. The length of this region corresponds at least to the maximum immersion depth (T) which the pipetting needle in a sample or reagent liquid reaches during an analysis run. Expediently, the length of this region corresponds at least to the maximum distance T _w (T _w = distance of the pipette needle tip to the rinsing nozzle opening) during a rinsing process. Accordingly, the pipetting needle may have a larger outer circumference outside this area.

In a further embodiment of the pipetting device according to the invention, the inner circumference (UW) of the rinsing bowl is in the range of 1.5 mm to 15 mm. Preferably, the inner circumference of the rinsing bowl is in the range of 4 mm to 9 mm.

Basically, it is sufficient for the rinsing station according to the present invention to provide only a Spülnapf. Preferably, however, at least two scavenging cups, which can be arranged in different areas of the working area of the pipetting arm of the pipetting device, are provided. However, the at least two dishwashing cups are particularly preferably arranged next to one another, with the dishwashing openings lying on a horizontal plane. Particularly preferred are rinsing stations in which at least three rinsing cups arranged in a row are provided, the rinsing bowl openings lying on a horizontal plane. In addition, more than three dishwashing cups can also be arranged on a straight line running through the center of the circle, with the dishwashing openings lying on a horizontal plane.

In the case of a pipetting arm which is movable both in the X-direction and in a direction Y arranged perpendicular thereto on a plane in the working area of the pipetting arm, the two or more flushing bowls having their Spülnapföffnungen in the working area of Pipettierarms on a common horizontal plane , Preferably so arranged on a line extending through the circle center line that this straight line at an angle to one on the plane of the Spülnapföffnungen projected path on which moves the pipette needle through the work area runs.

In the case of a pivotable Pipettierarms, one end of which passes through an axis of rotation about which the other end, on which the pipetting needle is arranged, moves in a circular path, is on the plane on which the Spülnapföffnungen lie, extending straight line on the the circle centers of the Spülnäpfe lie, a tangent of the projected to the plane of Spülnapföffnungen circular path on which moves the pipette needle through the work area or parallel to this tangent on the level of Spülnapföffnungen extending straight line.

In a rinsing station assembly having a plurality of rinsing cups arranged in a row, the inner circumference UW of the rinsing cups and the circumference of the rinsing cup openings and the angle at which the straight line on which the circle centers of the rinsing bowls lie are a trajectory projected onto the plane of the rinsing nozzle openings , on which the pipetting needle moves through the working area, cuts, so chosen that a pipetting needle, the tip of which does not move on the assumed ideal path, can still be introduced into one of the dishwashers, provided that the actual path on which the pipetting needle moves in the area between the outermost points of the two outermost Spülnapföffnungen. This is achieved, for example, by the Spülnapföffnungen are arranged offset one behind the other in the direction of movement of the pipette needle, wherein a pipette needle tip whose trajectory does not extend beyond the first Spülnapföffnung, in each case over a second Spülnapföffung runs, if the actual path on which the pipette needle moves in the area between the outermost points of the two outermost Spülnapföffnungen.

The pipetting device according to the invention preferably has a rinsing station in which a collecting trough is provided for the rinsing liquid emerging from the at least one rinsing bowl from the rinsing bowl outlet or above the upper edge of the rinsing bowl opening, in or above which the rinsing bowl or rinsing bowls are / are arranged. Optionally, this drip tray is equipped with a drain for the rinsing liquid.

Since the inner circumference (UW) and thus also the opening of a rinsing cup of the rinsing station according to the invention, through which the pipette needle is inserted into the rinsing bowl for the purpose of rinsing, should be kept as small as possible so that the desired cleaning effect is achieved with as little rinsing liquid volume at a given delivery rate It must be ensured that the pipetting needle meets this small opening during the flushing process.

For this purpose, the pipetting device according to the invention comprises, in addition to the rinsing station, a device for determining the exact position of the tip of the pipette needle. Preferably it is in this case, a measuring device which comprises at least one electrically conductive measuring body, which is arranged in the working area of the pipetting arm and can be controlled by the tip of an electrically conductive pipetting needle. With appropriate alignment of the pipetting needle tip, the pipette needle forms a capacitor with the measuring body, wherein the pipette blade forms a first electrode of the capacitor and the measuring body forms a second electrode of the capacitor. The capacitor is connected to a capacitance measuring device for measuring the electrical capacitance of the capacitor.

If the pipette needle tip is moved toward the measuring body, this is accompanied by a change in the capacity of the condenser formed by the pipette needle tip and measuring body. This capacitance change is used to either determine the exact position of the pipette needle tip on the at least one horizontal working plane in the working area of the pipetting needle. This position determination can be done in different ways.

For example, the position can be determined based on the predetermined position of the measuring body. Does the measuring body on the at least one horizontal working plane has a circular surface with a diameter which substantially corresponds to the diameter of the Pipettiemadelspitze on. If the pipette needle tip can be exactly aligned with this measuring body, a specific capacity is measured, which indicates the achieved exact alignment of the pipette needle tip on the measuring body and thus the exact position of the pipette needle tip on the corresponding working plane. If the measured capacity deviates from the value expected for this case, the position of the pipette needle tip is also different than expected.

If one wants to know more exactly how the pipette needle tip is aligned on the working plane, one can provide several measuring bodies, which are grouped in an arrangement. For example, the plurality of measuring bodies may be in a field of measuring bodies on the at least one horizontal working plane, all of which have a circular area with a diameter substantially equal to the diameter of the pipette needle tip and which are all separately connected to a respective associated capacitance measuring device. The position of the pipette needle tip is dependent on which measuring body and the pipette needle tip measure a certain capacity.

More precisely, the position determination can be based on the shape of a measuring body with a larger surface over which the pipetting needle is movable, and on the speed of movement of the pipetting needle over the measuring body and the time over which a certain capacity can be measured, or based take place in the movement over the measuring body set back route. Preferably, therefore, the measuring device as the second electrode next to the pipette needle exactly on an electrically conductive measuring body having a extending on at least one horizontal working plane surface (F), wherein the surface (F) is a triangle, a trapezoid, a rhombus or a Semicircle is.

Alternatively, the position can also be determined based on the predetermined position and shape of the measuring body and the distance traveled by the pipetting needle during the movement in the direction of the measuring body or the time required for reaching the measuring body at a given speed. For example, the measuring body may be an electrically conductive wire extending on at least one horizontal working plane at a predetermined angle to a path projected onto the horizontal working plane on which the pipetting needle moves through the working area. Preferably, a second measuring wire is additionally provided, which is on the same plane as the first wire at an angle to the first wire, i. not parallel to the first wire, runs.

In a particular embodiment, the measuring device comprises at least one electrically conductive measuring body, which is arranged in a recess in an area extending on the at least one horizontal working plane in the working area.

Preferably, the recess has a triangular, trapezoidal or semi-circular circumference in plan view from above, wherein the at least one measuring body extends along the circumference of the recess, thereby spanning a space having the same peripheral shape as the recess. As a result, the measuring body forms a measuring edge towards the interior of the depression, to which a pipetting needle introduced into the depression can be guided.

In an alternative embodiment of the invention, the measuring device may also comprise a voltage source connected to an electrical switch and a capacitance measuring or current measuring device connected to the electrical switch for detecting electrical current flow across the switch, the pipette needle tip forming a first contact of the switch and the at least one electrically conductive measuring body forms a second contact of the switch. However, this must be applied to the pipette needle a voltage, which can be associated with a number of disadvantages.

In a further alternative embodiment of the invention, the determination of the position of the pipette needle tip can also take place via a resistance measurement. For this purpose, instead of a capacitance measuring device, a resistance measuring device for measuring the resistance is preferably connected to the pipetting needle and to the measuring body. At a large distance between pipette needle tip and measuring body, the resistance is correspondingly large. If the pipette needle moves up the measuring body, the resistance decreases. If the pipette needle is even moved to contact with the measuring body, the resistance correspondingly approaches zero. However, a voltage must also be applied to the pipette needle, which can be associated with a number of disadvantages.

However, in the present invention, the capacitance measurement described above is preferred via the capacitance measuring device.

The capacity measuring device is expediently connected to a data processing unit for calculating the exact position of the pipette needle tip on the basis of the predetermined or measured data discussed above. In a preferred embodiment, this data processing unit is integrated in the analyzer.

Conveniently, the electrically conductive measuring body and the pipette needle are electrically insulated from the automatic pipetting device. In a preferred embodiment, the pipetting needle is connected to ground to avoid parasitic capacitances. In a further preferred embodiment, the measuring body is connected to ground in order to avoid interference capacitances. Particularly preferably, both the pipette needle and the measuring body have a ground connection.

In principle, the electrically conductive measuring body can consist of any electrically conductive material. The at least one electrically conductive measuring body preferably consists of metal.

The rinsing station of the automatic pipetting device according to the invention is preferably arranged exchangeably in the analyzer.

In a method according to the invention for rinsing the pipetting needle of an automatic pipetting apparatus with a rinsing station of the type described, a certain rinsing liquid is pumped through the pipetting needle into the rinsing bowl at a predetermined cross-section Q of the rinsing bowl, so that the delivery rate is greater than the rinsing rate of the rinsing liquid the Spülnapfablauf is.

Preferably, the rinsing liquid is pumped through the pipetting needle into the rinsing bowl with such a total delivery rate that the rinsing liquid in the region between the outer wall of the pipette needle and the inner wall of the rinsing bowl rises at least so that a height is reached which is at least equal to the predetermined maximum submergence depth (FIG. T) corresponds to the pipetting needle in a sample or reagent liquid during an automatic pipetting process. In a further preferred method, the rinsing liquid is pumped through the pipetting needle into the rinsing bowl with such a total delivery rate that the rinsing liquid rises to a height greater than the height (H) of the rinsing bowl so that the rinsing liquid overflows past the upper edge of the rinsing bowl can.

As already mentioned, the device according to the invention is part of an analyzer comprising one or more elements under a pipetting arm, a liquid container carousel drive device, a heat generating device, a cryogenic device, an optical measuring device for determining a physical or chemical size of the reaction mixture and an opto-electronic reading device for reading an opto-electronically readable code.

For purposes of the original disclosure, it is to be understood that all such features as will become apparent to those skilled in the art from the present specification, drawings, and claims, even though concretely described only in connection with certain further features, may be individually or any of them Compilations with other features or feature groups disclosed herein may be combined, unless expressly excluded or technical conditions make such combinations impossible or pointless. On the comprehensive, explicit representation of all conceivable combinations of features is omitted here only for the sake of brevity and readability of the description.

Further features or feature groups as well as examples of possible combinations of possible features will be disclosed or illustrated with reference to the following description of the attached figures.

Hereby show:

1 shows a device for the automated analysis of liquids (analyzer) with an automatic pipetting device with a rinsing station according to the present invention, Figure 2 is a schematic representation of the rinsing station for a pipette needle in the context of the present invention,

FIG. 3 a schematic representation of a special embodiment of a rinsing station according to the invention for the pipette needle,

Figure 4 is a schematic representation of a particular embodiment of the rinsing station according to the invention with several Spülnäpfen and FIG. 5 shows a pipetting device according to the invention with a rinsing station for the pipette blade and a measuring device for determining the exact position of the pipette blade tip.

FIG. 1 shows an apparatus for the automated analysis of liquids (analyzer), which has a carousel 1 for liquid containers and a pipetting apparatus 2 with a pipetting arm 5. The carousel 1 is arranged so that it can move the liquid container into the working area of the pipetting arm 5. In addition, a rinsing station 3 and a measuring device 4 for determining the exact position of the pipette needle tip are provided in the working area of the pipetting arm 5.

FIG. 2 shows schematically a rinsing station 3 in the sense of the present invention. In a collecting trough 31, in which a drain 34 is provided, an upwardly open, hollow cylindrical Spülnapf is arranged, wherein the height of the hollow cylinder is defined by H. The hollow cylinder has an inner circumference UW. At the upper edge of the hollow cylinder of the Spülnapf 30 is slightly widened to the outside. The Spülnapfboden 32 is tapered downwards in this embodiment, and opens into a Spülnapfablauföffnung 33rd

FIG. 3 shows a special embodiment of a rinsing station according to the invention. In this embodiment, the Spülnapfboden is designed so that the pipette needle tip can not be located directly above the Spülnapfablauföffnung 33, so that when ejecting the rinsing liquid from the pipette needle, the rinsing liquid jet is not pressed directly into the Spülnapfablauföffnung 33. Instead, the rinsing liquid initially passes into a drainage chamber 36, which is arranged between the rinsing cup base 32 and the hollow cylindrical section of the rinsing bowl 30. For Spülnapfhohlzylinder out the drain chamber 36 has a drain chamber inlet 37 and down the Spülnapfablauföffnung 33, which is arranged offset from the discharge chamber inlet 37.

FIG. 4 shows a rinsing station 3 in whose drip pan 33 three rinsing heads 30, 30 'and 30 "are arranged in a row.

FIG. 5 shows an automatic pipetting device 2 according to the invention with a pipetting arm 5, which is arranged pivotably about the rotation axis 59 and at the distal end of which a receiving device 50 for the pipetting needle is arranged. In the working region of the pipetting arm 5, ie on a circular path which can be controlled by a pipette needle about the axis of rotation 59, in this embodiment the automatic pipetting device is provided with three flushing cups 30, 30 ', 30 "arranged in a row and in a collecting trough 31 Flushing bowls 30, 30 ', 30 "are arranged on a straight line which surrounds the circular path on which the pipette needle tip is located. moves, cuts. This straight line runs parallel to a tangent of the circular path on which the pipette needle tip moves.

The rinsing cups are arranged so that the center of the central rinsing bowl 30 'lies on an imaginary ideal circular path on which the pipetting needle is to move. In contrast, the center of the rinsing bowl 30 "lies on a circular path which has a larger radius deviating from the ideal circular path The center of the rinsing bowl 30 lies on a circular path which has a smaller radius deviating from the ideal circular path Movement along the imaginary ideal circular path of the pipette needle arranged one behind the other.

The scope of the Spülnapföffnungen is in the given arrangement of the Spülnäpfe 30, 30 ', 30 "chosen so that the pipette needle can be inserted into any of the Spülnäpfe 30, 30', 30" in any case, provided that the Pipettiemadelspitze in a circular path, which is between the outermost edge of the outer Spülnapfs 30 "and the innermost edge of the inner Spülnapfs 30 moves.

Moreover, in this pipetting device, a measuring body 42 of a measuring device for determining the horizontal position of the pipette needle tip is likewise provided on a circular path around the rotation axis 59, which can be controlled with the pipetting needle. The measuring body 42 is provided in a triangular depression in the working surface 40. The measuring body 42 also has the circumference of a triangle, as it extends along the circumference of the recess and thereby spans a space having the same peripheral shape as having the recess. In this case, the measuring body 42 forms a measuring edge to which a pipetting needle introduced into the depression can be introduced.

The measuring body 42 and the electrically conductive pipette needle form, when they are aligned with each other, a capacitor which is connected to a capacitance measuring device. For the measurement, the pipette needle is inserted into the area spanned by the measuring body 42 and moved in one direction until a capacity of a certain size is detected. Alternatively, the pipetting needle can also be moved to contact, that is, until it hits the edge of the measuring body. Subsequently, the pipetting needle is moved in the opposite direction until a capacity of a certain size is determined or until it touches the edge of the measuring body. From the signals and from the distance traveled between the two end points, a data processing unit provided in the analyzer can determine the exact horizontal position of the pipette needle tip. It can be ascertained more precisely on which exact circular path the pipette needle tip moves. By this information, a selection can be made in which the rinsing cups 30, 30 ', 30 "of the pipette needle tip are best inserted to achieve the desired rinsing action. reference numeral

1 carousel for liquid container

2 pipetting device

3 rinsing station

5 pipetting arm

27 pipette needle

30 rinsing bowl

31 drip tray

32 Spülnapfboden

33 Spülnapfablauföffnung

34 outflow

35 Spülnapfanordnung

36 drain chamber

37 drain chamber inlet

41 pipette needle tip

42 measuring bodies

Claims

PATENT CLAIMS

1. Automatic pipetting device (2) with a rinsing station (3) for rinsing the pipetting needle (27) of the pipetting device (2), wherein the rinsing station (3) comprises at least one upwardly open rinsing cup (30) having a) a height (H), which corresponds to at least a predetermined maximum immersion depth (T) of the pipetting needle (27) in a sample or reagent liquid during an automatic pipetting process, b) whose inner circumference (UW) is greater than the outer circumference (UP) of the pipetting needle (27) and c) has at its lower end a Spülnapfboden (32) and in the Spülnapfboden (32) or immediately above arranged Spülnapfablauf (33), characterized in that at a given delivery rate (volume per time) of a particular rinsing liquid is selected by the pipette needle (27) in the rinsing bowl (30), the hydraulic flow resistance of the Spülnapfablaufs (33) so that the delivery rate of the rinsing liquid greater than di e Drain rate (volume per time) of the rinse liquid through the Spülnapfablauf (33).

2. Pipetting device (2) according to claim 1, characterized in that at a given delivery rate of a certain rinsing liquid through the pipette needle (27) into the rinsing bowl (30), the hydraulic flow resistance of Spülnapfablaufs (33) or the ratio UW / UP and the cross section Q of the Spülnapfablaufs (33) are selected so that with sufficient total amount of flushing fluid in the region between the outer wall of the pipette needle (27) and the inner wall of the Spülnapfs (30) in the rinsing fluid turbulent flow occurs.

3. Pipetting device (2) according to any one of claims 1 or 2, characterized in that the hydraulic outlet resistance of Spülnapfablaufs (33) or the ratio UW / UP and

Q are selected so that at a given delivery rate of a certain rinsing liquid in the area between the outer wall of the pipetting needle (27) and the inner wall of the Spülnapfs (30) in the rinsing liquid a Reynolds number of at least 2500 is reached.

4. Pipetting device (2) according to one of claims 1 to 3, characterized in that the hydraulic outlet resistance of the Spülnapfablaufs (33) or the ratio UW / UP and Q are chosen so that at a given delivery rate of a certain rinsing liquid in the range between the outer wall of the pipette needle (27) and the inner wall of the Spülnapfs (30) in the rinsing liquid a Reynolds number of at least 100 000 is reached.

5. Pipetting device (2) according to one of claims 1 to 4, characterized in that the outer circumference (UP) of the pipetting needle (27) is in the range of 1 mm to 4 mm.

6. Pipetting device (2) according to any one of claims 1 to 5, characterized in that the inner circumference (UW) of the Spülnapfs (30) in the range of 1, 5 mm to 15 mm.

7. Pipetting device (2) according to one of claims 1 to 6, characterized in that the ratio UW / UP is in the range of 1, 5 to 5.

8. Pipetting device (2) according to any one of claims 1 to 7, characterized in that it comprises a collecting trough (31) for the exiting from the at least one rinsing bowl rinsing liquid, in or above the rinsing bowl (30) or the rinsing bowls (30, 30 ', 30 ") is / are arranged, wherein the drip pan (31) is optionally equipped with a drain (34).

9. Pipetting device (2) according to any one of claims 1 to 8, characterized in that it comprises a device for determining the exact position of the tip of the pipetting needle (27).

10. Replaceable rinsing station (3) for rinsing the pipette needle (27) of an automatic pipetting device (2), wherein the rinsing station (3) has the features of the rinsing station (3) according to one of claims 1 to 9.

The automated analysis device comprising a pipetting device (2) according to any one of claims 1 to 9 or an automatic pipetting device (2) and a rinsing station (3) according to claim 10, wherein the automated analyzing device additionally comprises one or more elements under an analyzing motor Heat generating device, a cold generating device, an optical measuring device and an optoelectronic

Reading device for reading an opto-electronically readable code.

12. A method for rinsing the pipette needle (27) of an automatic pipetting device (2) with a rinsing station (3) according to one of claims 1 to 11, wherein at a predetermined cross-section Q of the Spülnapfablaufs (33) a certain rinsing liquid at a such delivery rate (volume per time) through the pipetting needle (27) in the rinsing bowl (30) pumps that the delivery rate is greater than the drainage rate (volume per time) of the rinse liquid through the Spülnapfablauf (33).

13. The method according to claim 12, wherein the rinsing liquid is pumped with such a total delivery through the pipetting needle (27) into the rinsing bowl (30) that the rinsing liquid in the area between the outer wall of the pipette needle (27) and the inner wall of the rinsing bowl (27). 30) at least until it reaches a height at least equal to the given maximum immersion depth (T) of the pipetting needle (27) into a sample or reagent liquid during an automatic pipetting process corresponds.

14. The method of claim 13, wherein the rinsing liquid is pumped with such a total delivery through the pipetting needle (27) in the rinsing bowl (30) that the rinsing liquid rises to a height greater than the height (H) of the rinsing bowl ( 30) so that the rinse liquid can overflow the upper edge of the rinsing bowl (30).