EP3393664B1 - Pipetting device and method for producing same - Google Patents

Description

The invention relates to a pipetting device and a method for producing this pipetting device.

Such pipetting devices are commonly used in medical, biological, biochemical, chemical and other laboratories. They are used in the laboratory for the transport and transfer of fluid samples, in particular for precise dosing of the samples. In pipetting devices, for example, liquid samples are sucked into pipetting containers, e.g. measuring pipettes, by means of negative pressure, stored there, and released from them again at the destination.

The pipetting devices include, for example, hand-held pipetting devices or automatically controlled pipetting devices, in particular computer-controlled automatic pipetting devices. These are usually air-cushion pipetting devices. In these, an air cushion is provided, the pressure of which is reduced when the sample is taken up in the pipetting container, as a result of which the sample is sucked into the pipetting container by means of negative pressure. Such pipetting devices are usually electrically operated devices, which are also referred to as pipetting aids.

Such pipetting devices are generally designed to pipette fluid samples with volumes in the range from 0.1 ml to 100 ml, for example. Such pipetting devices usually have an electrically driven pump, experience has shown that it is a diaphragm pump which is suitable for pipetting and which can therefore generate both negative and positive pressure. The term “pipetting” here encompasses both taking up the sample by suction by means of negative pressure and dispensing the sample by means of gravity and / or pressing out by means of positive pressure. A suction / pressure line is usually used for pipetting, the activity of which can be controlled by the operator using suitable valves in the housing body.

An example of a commercially available, hand-held, electric pipetting device is the Eppendorf Easypet® 3 from Eppendorf AG, Hamburg, Germany.

For better metering of the pipetted amount of liquid, devices are known which limit the volume flow in the pressure lines or suction lines, or adjust the output or the pressure of the pump accordingly.

In U.S. 3,963,061 and U.S. 6,253,628 describes valves which are intended to limit the volume flow in the pressure or suction lines. The valve needle is provided with a profile which changes the free passage area in the pressure or suction line depending on the stroke of the valve needle. Exact dosing, especially in the case of small-volume pipettes, can only be insufficiently achieved with such systems. Especially when the pump output is reduced, it becomes clear that the dosage is heavily dependent on the stroke frequency of the pump. Despite the reduced volume flow, the pulsations of the pump continue into the pipette and thus ensure that the liquid is dispensed in bursts. It is difficult to maintain an exact volume here.

The patent DE 103 22 797 describes an arrangement in which, in addition to the throttle elements in the pressure and suction lines, there are also separately throttled openings to the environment. These are directly connected to the pressure or suction line and are intended to limit the maximum overpressure or underpressure of the pump to a defined value. As a result, this arrangement is severely restricted in terms of variability. Before pipetting, the user must carefully consider which setting must be made on the throttles for the corresponding amount of fluid.

EP 2 633 914 A1 describes a pipetting device with a valve device for setting a pipetting pressure.

It is the object of the invention to provide a pipetting device which allows precise pipetting and dosing, in particular independently of the Pipetting container size is. Another object of the invention is to specify a method for producing this pipetting device.

The invention solves this problem with the pipetting device according to claim 1. Preferred embodiments are in particular the subject matter of the subclaims.

The advantage of the invention is that precise dosing of the pipetting volume is possible, which depends on the relationship between the closed states of the first and second chamber openings. The locked state can be: fully open, fully closed or partially closed.

As a result of the created bypass, fluctuations in the pump pressure (negative pressure and / or positive pressure) during dosing do not essentially continue completely into the pipetting container connected to the pipetting channel, in particular not at low pumping power. In the case of a pump device designed as a diaphragm pump, in particular the pulsations caused by the diaphragm movement do not essentially continue completely into the pipetting container. In the optional case of full performance of the pump device, even pipetting containers with small pipetting volumes (e.g. <5 mL) can be filled very precisely. The same applies when the fluid sample is dispensed from the pipetting container.

The closure surface is preferably a substantially planar surface that lies in one plane, and the first and / or second chamber opening, or a sealing section connected to this chamber opening, each has an opening edge that lies substantially in the same plane or on this adjoins. This enables the closure surface in contact with the respective chamber opening and / or its sealing section to slide along the respective chamber opening and / or its sealing section as a result of the movement controlled by the user. The contact is preferably such that in the closed closed state of the respective chamber opening a gas-tight sealing contact is achieved, so that in particular in the case of the completely closed second chamber opening the chamber pressure essentially completely determines the pipetting pressure, without pressure loss through the second chamber opening, and furthermore in particular in the case of the completely closed first chamber opening, the chamber pressure is the pipetting pressure im Essentially not influenced, since the chamber pressure is applied to the second chamber opening and thus to the bypass channel, the pump device preferably being deactivated in this position of the closure element and / or not influencing the pressure of the valve chamber.

However, the closure surface can also have a non-planar shape, in particular a cylindrical design that can be mathematically described by translating a circular shape, or another shape that can be described by translation or rotation of another shape, this other shape, for example, an ellipse, can be a triangle, square, pentagon, hexagon, or other polygon. The chamber openings or their sealing sections are then correspondingly shaped such that, at least in sections, a complete closure of the first and / or second chamber opening is achieved during the movement.

It is preferably provided that the closure element has at least one recess which extends from the closure surface into the depth of the closure element and which forms at least one closure surface opening in the closure surface, this at least one closure surface opening having a length which is measured parallel to the direction of this movement and a width that is measured perpendicular to it, the width of the at least one closure surface opening and / or the depth of the at least one recess changing at least in sections in the direction of this movement, and in particular the closure surface with the at least one closure surface opening at the first and / or the second chamber opening slides along that the closure cross-section of the first and / or second chamber opening changes during the movement.

By changing the shape, in particular the width and / or depth, of the recess along the direction of movement, the flow resistance through the connecting channel can be set, especially at a constant, predetermined chamber pressure or pump power, the connecting channel being the one between the valve chamber and the pipetting channel located flow sections ("first connecting channel") or between the valve chamber and the bypass channel located flow sections ("second connecting channel") referred to. The closing surface opening located in the closing surface can, in particular, have a course that tapers or widens in the direction of movement, and can in particular be triangular. The course can also be trapezoidal or rectangular.

Instead of a depression, the closure element can also have at least one elevation, which extends outward from the outside of the closure element and which forms a closure surface on the outside, the width and / or height of which changes along the direction B and the flow resistance through the first and / or determine the second chamber opening when the closure surface slides along the first and / or second chamber opening.

It is preferably provided that the width of the first closure surface opening and / or the depth of the first recess increases at least in sections in the direction of this movement and the width of the second closure surface opening and / or the depth of the second recess decreases at least in sections in the direction of this movement.

It is preferably provided that the first chamber opening and the at least one closing surface define a first connecting channel with a variable first flow resistance R1, this first connecting channel connecting the pipetting channel to the valve chamber, and the second chamber opening and the at least one closing surface having a second connecting channel with a variable second Define flow resistance R2, this second connecting channel connecting the bypass channel to the valve chamber, the distribution of the chamber pressure on the pipetting channel and the bypass channel changing the ratio R2 / R1, with the ratio increasing in particular during the movement.

It is preferably provided that the closure element has a first recess which, starting from the closure surface, extends into the depth of the closure element and which has a first recess in the closure surface Forms closure surface opening, and wherein the closure element has a second recess, which extends from the closure surface into the depth of the closure element and which forms a second closure surface opening in the closure surface, wherein in particular during the movement the first closure surface opening rests against the first chamber opening and the second Closing surface opening rests against the second chamber opening.

The first and second depressions are preferably arranged one behind the other in the same closure surface in the direction of movement, which then also applies in particular to the position of the first and second chamber opening. This enables a narrower design.

However, it is also possible for the first and second indentations to be arranged parallel to one another or offset in parallel next to one another in the at least one closure surface in the direction of movement, which then also applies in particular to the position of the first and second chamber opening. As a result, an available space in the direction of movement can be optimally used as an adjustment path for the pressure at the first / second chamber opening, so that a larger adjustment path is used per pressure change unit and the dosage can thus be better controlled by the user.

Preferably, in particular in the design according to the preceding paragraph, the first recess is arranged on a first closure surface of the closure element and the second closure surface is arranged on a second closure surface of the closure element. The first and second closing surfaces cannot be arranged parallel to one another on the closing element or can be arranged parallel to one another, in particular on opposite sides of the closing element.

The closure element can have a triangular cross section, a rectangular or square cross section, a pentagonal, hexagonal or generally polygonal cross section, or it can be oval or circular in the direction of the - in this case translational - movement. In the case of a polygonal cross-section, one is Closure surface preferably essentially planar. Depending on the number of closure surfaces, different dosing profiles can be implemented on the pipetting device, in particular to make different dosing speeds available. The closure element is preferably designed to be rotatable about the axis of the direction of movement, so that the user can align the desired closure surface with the first and second chamber openings.

It is preferably provided that the closure element has at least a first closure surface and a second closure surface which are non-parallel and in particular aligned at an angle of 60 ° <= α <= 120 ° to one another.

It is preferably provided that during this movement the first closure surface lies opposite the first chamber opening and slides along it, and the second closure surface lies opposite the second chamber opening and slides along it.

It is preferably provided that the first and / or second chamber opening has a sealing section which is contacted by the at least one closing surface, in particular in order to seal the first and / or second chamber opening essentially completely gas-tight in at least one position of the closing element.

It is preferably provided that the valve chamber and / or the closure element have at least one sealing section in order to seal the valve chamber essentially completely gas-tight in at least one position of the closure element and / or during the movement.

The expression "connecting two air-filled areas of the valve arrangement" means in the context of the present invention that the two areas are connected to one another by a connecting channel so that in particular air can be moved between the two areas, in particular can be moved independently of direction. Such a connection can in particular be indirect or "direct". The term "direct connection" of two air-filled areas of the valve arrangement In the context of the present invention means, in particular, that the two areas are connected by an unbranched connection channel, it being possible for a variable flow resistance to be provided in this connection channel, for example a device with a throttle function, in particular a throttle valve. In the case of an indirect connection, the two areas can be connected, for example, via several lines or chambers and / or, for example, along one or more branch points.

A channel, in particular a connecting channel, can be a line, in particular a hose line, or it can be an area of the valve arrangement or the pipetting device designed differently for guiding the flow medium, e.g. a channel integrated into a cast molding.

Preferably, precisely one pump device is provided, which in particular is or has a diaphragm pump. The pump device preferably has a first pump channel on the inlet side, which is designed as a suction channel for sucking the fluid sample into the pipetting container connected to the pipetting channel. The pump device preferably has a second pump channel on the output side, which is designed as a press channel for pressing out the fluid sample from the pipetting container connected to the pipetting channel.

The valve arrangement preferably has exactly one bypass channel. At least one pump channel connected directly to the pump device is preferably connected directly to the surroundings and / or the bypass channel. In the case of a valve device designed to aspirate the sample to be pipetted into the pipetting container, the output-side pump channel is preferably connected directly to the bypass channel and / or the environment. In the case of a valve device designed for pressing the sample to be pipetted out of the pipetting container, the pump channel on the inlet side is preferably connected directly to the surroundings and / or the bypass channel.

In a preferred embodiment of the invention, the pump device is connected to the valve chamber of a first valve device and connected to the valve chamber of a second valve device.

The pipetting channel is preferably connected to the valve chamber via a first connection channel with variable flow resistance and preferably the bypass channel is connected to the valve chamber via a second connection channel with variable flow resistance, the first flow resistance and the second to generate the desired pipetting pressure in the pipetting channel Flow resistance can be adjusted by the valve device, in particular adjusted at the same time. Variable flow resistances can be structurally integrated relatively efficiently.

The valve device preferably has a closure carrier element and preferably at least one closure element, which is arranged to be preferably translationally movable, preferably rotationally movable, preferably translationally and / or rotationally movable at least between a first position and a second position relative to the closure carrier element and / or the valve chamber.

In the first position, the closure element preferably closes the first connecting channel and / or the first chamber opening and preferably at the same time does not close the second connecting channel and / or the second chamber opening.

In the second position, the closure element preferably does not close the first connection channel and / or the first chamber opening and preferably simultaneously closes the second connection channel and / or the second chamber opening.

With the closure element, in particular with a single closure element, in particular the first flow resistance and the second flow resistance can be adjusted simultaneously. This way is an easy one Realization of the setting of the pipetting pressure is possible, which is also known as metering the pipetting pressure.

A closure element is preferably a valve piston, and the closure carrier element and / or the valve chamber is in this case preferably designed as a piston carrier element and / or a piston cylinder element. As a result, a precise translation of the movement of the valve piston into a pressure change in the first and / or second connecting channel and thus a precise setting of the pipetting pressure in the pipetting channel is possible. It is also possible and preferred that the closure element is not designed as a valve piston and the valve chamber is not designed as a piston cylinder. The gas-tight seal between the closure element and valve chamber is then preferably carried out by a sealing section, e.g. an elastic sealing ring or O-ring, e.g. made of silicone, which can be arranged or attached to the closure element or to the valve chamber or to the closure carrier element.

The closure element and / or the valve chamber and / or the closure carrier element is preferably an injection-molded part, which enables efficient production. In particular, the shaping of the at least one closure surface can be efficiently designed by manufacturing using the injection molding process. The closure element could also be manufactured as a turned part by turning or as a milled part by milling, or by a combination of such manufacturing processes.

The closure element is preferably spring-mounted with a spring device which presses the closure element into the first position and which is tensioned by moving the closure element from the first position into the second position.

The closure element is preferably designed such that it partially opens the first connection channel and the second connection channel when it is arranged in at least one third position between the first and the second position. Preferably, the first connection channel and the second connection channel are at least halfway between the first and second Position partially open. This third position enables the pump device to be connected not only to the pipetting channel, but at the same time also to the bypass channel open to the environment. In this way, fluctuations in the chamber pressure are at least not completely transmitted to the pipetting channel, but rather damped. This enables precise pipetting.

The closure element is preferably designed such that it closes the first connection channel further in a third position than in a fourth position, and preferably closes the second connection channel further in the fourth position than in the third position. The third position and fourth position are in particular between the first position and the second position. This measure enables a targeted adaptation of the distribution of the pressure drop from the chamber pressure via the pipetting channel and via the bypass channel as a function of the position of the closure element. Preferably, the third position is closer to the first position and the second position is closer to the fourth position.

The pipetting device can preferably be operated manually, the valve device being designed so that the position of the closure element is determined by the user in order to set the desired pipetting pressure in the pipetting line. It is preferably provided that the movement of the closure element is driven by the user. However, it is also possible for the movement of the closure element to be driven electrically and, in particular, to be controlled by a preferably provided electrical control device of the pipetting device.

In a first preferred embodiment of the invention, the pump device is connected to the valve chamber of a first valve device and connected to the valve chamber of a second valve device. A first pump channel of the pump device is preferably connected to the first valve device and a second channel of the pump device is connected to the second valve device. The pump device preferably has a pump, in particular a membrane pump, preferably a single pump. According to the first preferred embodiment of the invention the pipetting device preferably has at least one, preferably exactly one, first valve device with a first valve chamber and one, preferably exactly one, second valve device with a second valve chamber, the at least one, preferably exactly one, pump device for generating a first chamber pressure in the first Valve chamber is connected to this first valve chamber and is connected to this second valve chamber to generate a second chamber pressure in the second valve chamber, the first valve chamber and the second valve chamber each with the at least one, preferably exactly one, pipetting channel and the at least one, preferably exactly connected to a bypass duct. The first valve device is preferably designed such that a pressure is set in the pipetting channel which is suitable for sucking a fluid sample into a pipetting container connected to the pipetting channel in an airtight manner. The second valve device is preferably designed such that a pressure is set in the pipetting channel which is suitable for dispensing a fluid sample from a pipetting container connected airtight to the pipetting channel.

Preferably, the pipetting device can also be operated manually and is designed such that the connecting channel between the first valve chamber and the pipetting channel is at least partially open for sucking in the fluid sample and the connecting channel between the second valve chamber and the pipetting channel is closed, and that preferably for dispensing the fluid Sample, the connecting channel between the first valve chamber and the pipetting channel is closed and the connecting channel between the second valve chamber and the pipetting channel is at least partially open.

Preferably, the pipetting device can also be operated manually and is designed in such a way that the connecting channel between the first valve chamber and the bypass channel is at least partially open or closed for sucking in the fluid sample and the connecting channel between the second valve chamber and the bypass channel is open, and that preferably the connecting channel between the first valve chamber and the bypass channel is open to deliver the fluid sample and the connecting channel between the second valve chamber and the bypass channel is at least partially or completely open.

Preferably, the pipetting device is also designed such that the bypass channel essentially only exchanges that volume of air with the environment that corresponds to the volume of air that is required to set the desired pipetting pressure in the pipetting channel, with an air exchange preferably only occurring when the Pipetting pressure takes place and preferably does not occur substantially when the desired pipetting pressure is reached. The volume of air exchanged between the valve arrangement and the environment is preferably the net volume flow of the air during the suction process or during the extrusion process. This embodiment offers the advantage that the air is exchanged with the environment essentially only to the extent that it is necessary to change the pipetting pressure. On the one hand, this avoids unnecessarily harmful, for example moist, ambient air being drawn into the valve arrangement. On the other hand, the air from the valve arrangement is not released into the environment to an unnecessary extent, which is more comfortable for the user.

The pipetting device preferably has exactly one pump device and at least one first pump channel for the sucked-in air, which is connected to the pump device on the suction side, and a second pump channel for the discharged air, which is connected to the pump device on the pressure side, the first pump channel preferably being connected to the is connected to the first valve chamber and the second pump channel is connected to the second valve chamber, so that both the suction pressure in the first valve chamber and the discharge pressure in the second valve chamber can be produced by means of the one pump device. Such an arrangement is particularly inexpensive to implement.

In a second preferred embodiment of the invention, the valve arrangement has exactly one valve device. In this case in particular, the pump device is preferably designed to reverse the pumping direction so that each of the two Pump channels of the pump device can function both as a suction channel (input channel) and as a pressure channel (output channel).

The pipetting device is preferably designed as a hand-operated electrical pipetting device, which in particular has a pistol-like handle, which has at least one actuating element that can be adjusted by the user, by actuating it to generate the desired pipetting pressure in the pipetting channel, the chamber pressure is controlled by the user and controlled by the at least one Valve device is dosed distributed to the pipetting channel and the bypass channel.

The pipetting device preferably has a device for automatically adjusting the pumping power of the at least one pump device as a function of the position of the closure element of the valve device with respect to the base body of the valve device. The pipetting device preferably has a device for automatically setting the pump output of the at least one pump device as a function of the position of the actuating element relative to the base body of the valve device. This device can have a position sensor for detecting the position of the closure element, in particular the valve piston, and / or the actuating element. The position sensor can be a Hall sensor. Alternatively, optical position detection would also be possible. The maximum pump power can also be set manually using an adjustable resistor, in particular a manually adjustable resistor, and in particular using a potentiometer. The pipetting device preferably has an adjustable resistor and is designed in particular to set the maximum pump power by means of the adjustable resistor.

• Fertigen der mindestens einer Ventileinrichtung der Ventilanordnung zumindest teilweise aus einem ersten Material, das insbesondere Kunststoff, Verbundstoff oder Keramik sein kann; vorzugsweise: Fertigen mindestens eines Verschlusselements, insbesondere aus insbesondere Kunststoff, Verbundstoff oder Keramik, insbesondere aus Metall z.B. als Dreh- oder Frästeil, oder als kombiniertes Dreh- /Frästeil, d.h. als ein durch die Kombination eines Dreh- und Fräsverfahren gefertigtes Teil, und insbesondere aus Kunststoff mittels Spritzgussverfahren;
• Fertigen des mindestens einen Pipettierkanals, und insbesondere auch des mindestens einen Bypasskanals, zumindest teilweise aus einem zweiten Material, das insbesondere verschieden ist von dem ersten Material;
• vorzugsweise: zumindest teilweises Fertigen des mindestens einen Pipettierkanals, und insbesondere auch zumindest teilweise des mindestens einen Bypasskanals, insbesondere einstückiges Fertigen, insbesondere unter Verwendung eines Gussverfahrens, wobei das zweite Material insbesondere Kunststoff ist.

The method according to the invention for producing the pipetting device according to the invention preferably has the steps:

• Manufacturing the at least one valve device of the valve arrangement at least partially from a first material, which can in particular be plastic, composite material or ceramic; preferably: manufacture of at least one closure element, in particular from plastic, composite material or in particular Ceramic, in particular made of metal, for example as a turned or milled part, or as a combined turned / milled part, ie as a part manufactured by combining a turning and milling process, and in particular made of plastic by means of an injection molding process;
• Manufacturing the at least one pipetting channel, and in particular also the at least one bypass channel, at least partially from a second material that is in particular different from the first material;
• preferably: at least partially manufacturing the at least one pipetting channel, and in particular also at least partially manufacturing the at least one bypass channel, in particular one-piece manufacturing, in particular using a casting process, the second material being in particular plastic.

In the valve arrangement, at least one support component is preferably provided, which is manufactured in one piece and which preferably has at least part of the pipetting channel, preferably has at least part of the bypass channel and preferably at least part of the valve chamber of at least one valve device, preferably of exactly two valve devices, having. This carrier component preferably has at least one receiving area for receiving a piston carrier element, in particular precisely two such receiving areas.

A pipetting container is in particular a hollow cylinder-like container that has a first opening for receiving / dispensing the fluid sample and at least one second opening for applying the pipetting pressure. The pipetting container preferably has a connecting section with which it can be detachably connected, in particular airtight and pressure-tight, to the corresponding, preferably provided, connecting section of the pipetting device. A pipetting container is preferably a commercially available graduated pipette or volumetric pipette. The possible pipetting container sizes, that is to say the maximum capacity of a pipetting container, can in particular be between 0.1 ml and 100 ml. The fluid sample is usually a liquid, in particular predominantly aqueous sample, for example a physiological aqueous solution.

• Fig. 1 zeigt in einer schematischen Seitenansicht ein erstes Ausführungsbeispiel der erfindungsgemäßen Pipettiervorrichtung.
• Fig. 2a zeigt eine Querschnittsansicht durch eine Ventileinrichtung der Pipettiervorrichtung in Fig. 1, gemäß einer ersten bevorzugten Ausführungsform der Erfindung, in einem ersten Zustand.
• Fig. 2b zeigt die Ventileinrichtung der Fig. 2a in einem zweiten Zustand.
• Fig. 2c zeigt die Ventileinrichtung der Fig. 2a in einem dritten Zustand.
• Fig. 3a zeigt eine isometrische Schrägansicht eines bei der Ventileinrichtung einer erfindungsgemäßen Pipettiervorrichtung einsetzbaren Verschlusselements, gemäß einem ersten Ausführungsbeispiel.
• Fig. 3b zeigt eine isometrische Schrägansicht eines bei der Ventileinrichtung einer erfindungsgemäßen Pipettiervorrichtung einsetzbaren Verschlusselements, gemäß einem zweiten Ausführungsbeispiel.
• Fig. 3c zeigt eine isometrische Schrägansicht eines bei der Ventileinrichtung einer erfindungsgemäßen Pipettiervorrichtung einsetzbaren Verschlusselements, gemäß einem dritten Ausführungsbeispiel.
• Fig. 3d zeigt eine isometrische Schrägansicht eines bei der Ventileinrichtung einer erfindungsgemäßen Pipettiervorrichtung einsetzbaren Verschlusselements, gemäß einem vierten Ausführungsbeispiel.
• Fig. 3e zeigt eine isometrische Schrägansicht eines bei der Ventileinrichtung einer erfindungsgemäßen Pipettiervorrichtung einsetzbaren Verschlusselements, gemäß einem fünften Ausführungsbeispiel.
• Fig. 4 zeigt eine isometrische Schrägansicht des bei der Ventileinrichtung in Fig. 3a der erfindungsgemäßen Pipettiervorrichtung verwendeten Ventilkammerabschnitts mit Pipettierkanal und erster Kammeröffnung.

Further preferred configurations and features of the pipetting device according to the invention and the method according to the invention for its production emerge from the following description of the exemplary embodiments in conjunction with the figures and their description. The same components in the exemplary embodiments are essentially identified by the same reference symbols, unless otherwise described or if the context does not indicate otherwise. Show it:

• Fig. 1 shows in a schematic side view a first embodiment of the pipetting device according to the invention.
• Fig. 2a FIG. 11 shows a cross-sectional view through a valve device of the pipetting device in FIG Fig. 1 , according to a first preferred embodiment of the invention, in a first state.
• Figure 2b shows the valve device of Fig. 2a in a second state.
• Figure 2c shows the valve device of Fig. 2a in a third state.
• Fig. 3a shows an isometric oblique view of a closure element that can be used in the valve device of a pipetting device according to the invention, according to a first exemplary embodiment.
• Figure 3b shows an isometric oblique view of a closure element that can be used in the valve device of a pipetting device according to the invention, according to a second exemplary embodiment.
• Figure 3c shows an isometric oblique view of a closure element that can be used in the valve device of a pipetting device according to the invention, according to a third exemplary embodiment.
• Fig. 3d shows an isometric oblique view of a closure element that can be used in the valve device of a pipetting device according to the invention, according to a fourth exemplary embodiment.
• Figure 3e shows an isometric oblique view of a closure element that can be used in the valve device of a pipetting device according to the invention, according to a fifth exemplary embodiment.
• Fig. 4 FIG. 11 shows an isometric oblique view of the valve device in FIG Fig. 3a the valve chamber section with pipetting channel and first chamber opening used in the pipetting device according to the invention.

Fig. 1 shows an embodiment of a pipetting device 1 according to the invention. This pipetting device 1 serves as an electrically operated, manual pipetting aid for use with volumetric pipettes or graduated pipettes 9 made of glass or plastic, which are available in various sizes with filling volumes between 0.1 mL (milliliters) and 100 mL via laboratory supplies are available.

The terms “above” and “below” are used in particular to describe the invention. These relate to an arrangement of the pipetting device in space in which a pipetting container which extends along a longitudinal axis and is connected to the pipetting device is arranged parallel to the direction of gravity, ie vertically. The indication of direction "downwards" indicates the direction of gravity, the indication of "upwards" the opposite direction.

The pipetting device 1 is an air-cushion pipetting device which is used in particular for pipetting a fluid sample by suction into a pipetting container using air under a first pipetting pressure and / or for dispensing or expressing a fluid sample from a pipetting container by means of a pipetting pressure under a second pipetting pressure Air serves. The air-cushion pipetting device uses air as the working medium to transport the fluid sample into the To effect pipetting container and out of this. This is explained further below:
In Fig. 1 the fluid sample 9a in the pipetting container 9 is shown hatched. Above the hatched area, in area 9b of the pipetting container, there is air that has expanded in relation to the ambient pressure, that is to say is under a negative pressure. The negative pressure is the pipetting pressure applied via the pipetting channel of the pipetting device to aspirate the sample, which is shown in Fig. 1 holds the sample 9a against the force of gravity at a constant height in the container. The first pipetting pressure for aspirating the sample is selected in particular so that it is at least lower than the ambient pressure to which the sample to be pipetted is exposed. The first pipetting pressure for aspirating the sample is selected in particular so that it applies the counterforce required to lift or hold the liquid column 9a in the pipetting container 9, which is in particular essentially at least as great as the weight of the liquid column 9a. The second pipetting pressure for dispensing the fluid sample 9a from the pipetting container 9 must be at least lower than the first pipetting pressure, in particular at least so small that the liquid column overcomes the counterforce caused by the pipetting pressure (negative pressure) and is released due to gravity. To express the fluid sample from the pipetting container, the second pipetting pressure is in particular at least greater than the ambient pressure.

The pipetting device 1 has a housing 2 as the base body 2, which has a cantilever section 4, at the end of which a connecting section 5 of the pipetting device is provided on its underside, on which the pipetting container 9 is detachably and airtightly connected to the connecting section 5. The connecting section is designed here as an exchangeable, screwable receiving cone 5. It contains a clamping section (not visible) for frictionally holding the pipetting container 9 which can be inserted into the clamping section and a membrane filter (not visible) which is inserted into the pipetting channel between the boom section 4 and the pipetting container 9. The membrane filter prevents the fluid sample to be pipetted from entering the pipetting device or its Valve device penetrates. In this way, the functionality of the pipetting device is guaranteed.

The base body 2 also has a pistol-like grip section 3. In the interior of this grip section 3, a battery unit or accumulator unit 6 is arranged in a downwardly open or openable accumulator compartment. The accumulator unit 6 can, for example, have a nickel-metal hydride or a lithium polymer or a lithium-ion / polymer accumulator which can provide an operating voltage of 9V, for example. The accumulator unit 6 can be removed downwards from the base body 2 in the manner of a pistol magazine and is preferably held on the base body by a latching device (not shown). A pump device 7, which is electrically operated by the operating voltage of the accumulator unit and has an electrically operated diaphragm pump with adjustable pumping power, is also accommodated in the interior of the handle section 3. An electrical control device 8 in the interior of the housing 2 has electrical circuits, in particular programmable electrical circuits. The control device 8 is designed to control at least one function of the electrically operated pipetting device 1.

In the interior of the handle section 3, a valve arrangement with two valve devices is also arranged, which in particular according to FIG Figures 2a to 2c can be designed and in which in particular a closure element can be adapted, as in one of the Figures 3a to 3e is shown.

The pipetting device 1 has two actuating elements 11, 12 for manually actuating the two valve devices of the valve arrangement. The actuating elements are designed as pushbuttons 115 spring-loaded by means of a spiral spring 131, the spiral spring 131 of which is tensioned when the pushbutton is moved by the user's finger from its starting position into the depressed position. The push buttons 11, 12 can be moved independently of one another. The two actuating elements 11, 12 are arranged parallel one above the other and horizontally movable and cannot be lost on the base body 2. Each actuator 115 is preferably at least in one direction along axis A (see Fig. 2a ) essentially rigidly attached to a closure element 110 of a valve device 101 of the valve arrangement, in particular by means of injection molding as a component manufactured in one piece with the closure element 110, in the case of the valve device 101 according to the first preferred embodiment of the invention.

As in the Figures 2a to 2c is shown, by means of movement B, the user guides the closure element from the first position shown in FIG Fig. 2a is shown in the third position shown in Figure 2b is shown, and from there optionally to the second position shown in Figure 2c is shown. If the user exerts a lower force than is applied by the compressed spiral spring 131 between the valve support element 111 and the closure element 110, the closure element is reset by the spring force.

In the first position, shown in Fig. 2a , the pipetting channel 103 and the first chamber opening 113 of the valve chamber 106 are completely closed by the planar closing surface 120 in the edge of the first chamber opening or the preferably provided there in Fig. 4 as a silicone O-ring 113 designed sealing portion 113 'is contacted in a sealing manner, so that a gas passage through the first chamber opening 113 is prevented, in particular in every typical operating state of the pipetting device. The in Fig. 4 The sealing section shown can, generally in the context of the present description of the invention, not only be an elastic O-ring, but also, for example, completely as an elastomer section of the pipetting channel, in particular the pipetting channel can be partially or entirely made of elastomer. In the first position of the closure element, the bypass channel 104 is also open, namely not closed by the closure surface 120, since the second chamber opening 114 here lies opposite the second recess 122 of the closure element. The second recess 122 keeps the flow path through the second chamber opening 114 open to the maximum here, so that a chamber negative pressure or chamber positive pressure, based on the ambient pressure, i.e. here the atmospheric pressure, would cause a flow through the bypass channel 104 if the pump device were active and through the Pump channel would apply a flow. However, in the first position, the pump device is preferably inactive, in particular when the Pump device is only activated mechanically by deflecting the actuating button 115. In the first state of the valve arrangement, in particular a liquid column 9a can be kept at a constant height in the pipetting channel with a suitable pipetting pressure (negative pressure).

In the second position, shown in Figure 2c , the bypass channel 104 and the second chamber opening 114 of the valve chamber 106 are completely closed by the planar closure surface 120 in the edge of the second chamber opening or the preferably provided there in Fig. 4 sealing section 113 'designed as a silicone O-ring 113' is contacted in a sealing manner, so that a gas passage through the second chamber opening 114 is prevented, in particular in every typical operating state of the pipetting device. In the second position of the closure element, the pipetting channel 103 is also open, namely not closed by the closure surface 120, since the first chamber opening 113 here lies opposite the first recess 121 of the closure element. The first recess 121 keeps the flow path through the first chamber opening 113 open to the maximum here, so that the negative chamber pressure or positive chamber pressure, based in a first approximation to the ambient pressure (more precisely: based on the inactive pump and stationary liquid column 9a in area 9b and in the pipetting line applied pressure, which differs from the ambient pressure because of the gravitation and suction effect of the liquid sample 9a in the pipette 9), causes a maximum air flow through the pipetting channel 103.

In a third position, shown in Figure 2b , in which the closure element is arranged between the first and second positions, the first chamber opening 113 and the second chamber opening 114 are each partially opened. This results in a first flow resistance through the first connecting channel, which is determined by the flow sections located between the valve chamber 106 and the pipetting channel 103. These flow sections include, in particular, the section of the first closure surface opening of the first recess 121 which adjoins the first chamber opening in this third position and opens into the closure surface 120. A cross section of the first depression 121 that changes along the direction of movement B is realized here, which is caused by a changing width of the depression and / or the closure surface opening can be given along the direction B or by a depth that changes along the direction B, see the embodiments of possible closure elements and their depressions in FIG Figures 3a to 3e . The cross-section of the first recess 121, which changes along the direction B, realizes a first flow resistance that is dependent on the position of the closure element.

Analogously, there is a second flow resistance through the second connecting channel, which is determined by the flow sections located between the valve chamber 106 and the bypass channel 104. These flow sections include, in particular, the section of the closure surface opening of the second recess 122 which adjoins the second chamber opening 114 in this third position and opens into the closure surface 120. Due to the ratio R2 / R1 of the second flow resistance R2 to the first flow resistance, the chamber pressure in the valve chamber can be distributed or dosed to the pipetting channel and the bypass channel, so that the pressure desired by the user is generated in the pipetting channel, for suction or ejection of the liquid sample 9a from the pipette 9.

The pipetting device preferably has a locking device which automatically locks one actuating element 11, in particular locks it when the other actuating element 12 is actuated, and vice versa. The locking device can have a locking element which is mechanically displaced by actuating one actuating element in order to block the mobility of the other actuating element in a locking state. The locking device can, however, also be designed for the electrical setting of the locking state.

The first actuation element 11 is used to suck the fluid sample into the pipetting container. The second actuation element 12 serves to dispense or press out the fluid sample from the pipetting container.

In the exemplary embodiment, the valve arrangement of the pipetting device 1 is made from various components which are in particular plugged together. These components include in particular a carrier component (not shown), in particular two lock carrier elements, two lock elements 110, 110 'and sealing rings, in particular sealing rings 113'. A sealing section, in particular a sealing ring, can in particular be provided at the outer end 132 of the valve chamber 106 or of the closure carrier element 111, as in FIG Fig. 2a is shown. The lock carrier element 111 can have a shape which, in its interior, is adapted to the shape of the lock element 110, and which in particular enables the translational movement B of the lock element 110 in the interior of the lock carrier element 111. For this purpose, the valve chamber 106 is designed as a receiving section of the closure element 110.

Each receiving section is open to the outside on one side in order to enable the insertion of a first closure element 110 or a second closure element 110 '. A closure element preferably has a slight clearance fit with respect to its receiving section, so that the non-positive fastening of a closure element in the receiving section can take place by pressing together at least one sealing ring, e.g. at position 132 ( Fig. 2a ). The sealing rings are preferably designed to be sealed in such a way that they produce an air- and (negative) pressure-tight seal when the pipetting device is used as intended.

The manufacture of the valve arrangement is particularly simple and inexpensive, and at the same time efficient, because the components mentioned can be assembled simply by plugging them together, in particular without the use of special tools and / or complicated fastening steps during assembly.

The further the closure element 110 is moved into the first position, the greater the proportion of air that is drawn through the bypass channel 104. As a result, the proportion of air that is sucked through the pipetting channel is correspondingly lower. This has the consequence that the elevator speed (volume per time) of the fluid sample in the with the pipetting container connected to the pipetting channel and the maximum liquid column in the pipetting container are low due to the gravitation acting on the liquid column. Correspondingly, the further the closure element 110 is moved into the second position, the lower the proportion of air that is drawn through the bypass channel 104. As a result, the proportion of air that is sucked through the pipetting channel is correspondingly larger. If the closure element 110 is moved maximally into the closure carrier element 111 (second position), then essentially no more air is drawn via the bypass line 104. As a result, the amount of air sucked in from the pipetting channel 103 reaches a maximum value. The consequence of this is that the elevator speed and the liquid column in the pipetting container are each maximum. In addition to controlling the elevator speed via the bypass channel 104, the change in cross section, in particular the conical shape of at least one recess (121, 122) in the closure element 110, regulates the air speed on the path of the air flow from the entry into the interior area of the closure carrier element 111 to the pipetting channel 103 This functionality of the valve arrangement is described in particular below. In this way, the speed at which the liquid column is lifted into the pipetting container can be dosed even more finely.

If, based on the second state of the valve device 101 in FIG Figure 2b , the closure element 110 is moved from the third position back into the first position by the user in order to end the suction process, it is preferably provided that the pump output is regulated in a predetermined manner by the electrical control device in order to be able to flow in the first depending on the first flow resistance Connecting channel to adjust the pumping power so that the pipetting pressure remains constant until the first position of the closure element is reached again. As a result, the liquid column sucked in by the user in the pipetting container remains at a constant volume. In particular, it is possible that when the closure element moves from the third position into the first position, the pump power that is present in the third position is kept at least constant until the first position is reached.

The pipetting pressure in the pipetting channel 103 is set in each case by a valve device, while the other valve device essentially does not influence it, in that in particular the first connecting channel of the other valve device is closed. The second connecting channel or the second chamber opening is in particular in the third position, which lies between the position of the closure element in the first and / or second position, preferably at least partially open, and is in particular in a third position, which is closer to the first position than opened at the second position, preferably to at least half of the maximum opening or the maximum opening volume. Through this respective bypass connection of the valve chamber of the valve device with the environment it is achieved in particular that pressure fluctuations in the valve chamber, which can arise from the pump device, are not fully transferred to the pipetting channel and thus to the liquid column, but rather proportionally to the bypass Environment and thus are efficiently damped in particular in the case of small deflections of the valve piston from the first position and in particular in the case of low pump outputs and / or pump frequencies. At full pumping capacity, even pipetting containers with small dispensing volumes can be filled very precisely. In this way, more precise and comfortable pipetting is possible.

The pipetting behavior is further coordinated in the pipetting device 1 in that the pump output is continuously variable. For this purpose, the base body 2 has at least one Hall sensor as a position sensor (not shown), by means of which the position of the closure element with respect to the base body or with respect to the closure carrier element 111 is detected. The electrical control device 8 is designed to change the pumping power depending on the measured position and / or measured speed of the valve piston 110 along the axis A, in particular to increase the pumping power when the user pushes the closing element further into the Inside of the shutter carrier member 111 is pressed. In this way, the use of the pipetting device becomes even more efficient, in particular more convenient, and the coordination of the pump power becomes even more flexible. In particular, the pump can be switched on immediately by means of the position sensor or another, for example mechanical, switch be switched on. The mechanical switch can be automatically triggered, for example, by a tab on the actuating element when the actuating button is pushed out of the starting position by the user, preferably when the valve piston is moved out of the first position by the user. This applies at least to the actuating element for sucking in the sample. In the case of the actuating element for dispensing the sample, it is preferably provided that the pump only becomes active when a certain third position of the closure element 110, i.e. the depth of the depression, is reached, since before the third position is reached, the dispensing takes place due to gravitation and does not require any excess pressure. The sample delivery, which is controlled by opening the second connecting channel, is efficient and convenient, and the pumping activity can additionally accelerate the delivery to the desired extent.

Another particular advantage of the pipetting device according to the invention according to the first preferred embodiment with the valve arrangement is as follows: The pipetting device is designed in such a way that the bypass line 104 essentially only exchanges the air volume with the environment that corresponds to the air volume that is required to set the desired Pipetting pressure is required in the pipetting channel, an exchange of air preferably taking place essentially only when the pipetting pressure is set and preferably not taking place when the desired pipetting pressure is reached. This exchanged air volume represents, in particular, a net flow between the flow areas of the valve arrangement and the environment, that is to say either the net volume reference of air from the environment or the net volume output of air to the environment. In this way, less - potentially harmful, e.g. moist - outside air reaches the duct areas of the valve arrangement and, conversely, less air is released from the valve arrangement to the environment, which is more comfortable for the user.

In the exemplary embodiment, this is achieved in particular in that the pipetting device has precisely one pump device, for example with precisely one membrane pump, and at least one first - or precisely one first - pump channel 105 for the air that is sucked in, which is connected to the pump device on the suction side and at least one second - or exactly one second - pump channel for the air dispensed, which is connected on the pressure side to the pump device, the first pump channel being connected to the first valve chamber of the first valve device and the second pump channel being connected to the second valve chamber of the second valve device, so that both the suction pressure in the first valve chamber and the Delivery pressure can be produced in the second valve chamber.

Fig. 3a shows the closure element 110 which can be used in a pipetting device 1 according to the invention, according to a first exemplary embodiment. The closure element has a first closure surface 120 which is planar and is arranged parallel to the direction of movement B. The closure element is also triangular in cross section, viewed perpendicular to the direction of movement B, here according to an equilateral triangle, the sides of which are at an angle of α = 60 ° to one another. Other cross-sectional shapes with a different number of sides, in particular planar sides, are possible and preferred. The area of the closure element with the closure surfaces 120 does not serve as a piston element which seals the interior of the closure carrier element. It is only provided that the respective closure surface 120, 120 ′ can slide parallel along the first and second chamber openings 113, 114 in order to close them completely or partially in a gas-tight manner, depending on their position.

The shape of the first closure surface differs from the shape of the second closure surface. The user can remove the closure element from the closure carrier element 111, rotate it and insert it again in such a way that another closure surface faces the first and second chamber openings. This sets a different pipetting behavior of the pipetting device, in particular influencing the pipetting speed. The first recess 121 of the first closure surface 120 preferably differs in its width and / or depth from the first recess 121 'of the second closure surface 120'. The second recess 122 of the first closure surface 120 preferably differs in its width and / or depth from the second recess 122 'of the second closure surface 120'.

In principle, it is also possible and preferred for the closure element to have only a single closure surface in order to implement only a single pipetting behavior of the pipetting device. The closure element can then also be permanently connected to the closure carrier element 111.

Figure 3b shows the closure element 110a which can be used in the pipetting device according to the invention, according to a second exemplary embodiment. The closure element is designed similar to the closure element 110, but has recesses 121a, 122a, 121a ', 122a', the width of which is essentially constant, so that a rectangular closure surface opening results. The flow resistance that changes along the direction B is here essentially achieved by a depth of the depression that changes along the direction B.

Figure 3c shows the closure element 110b which can be used in the pipetting device according to the invention, according to a third exemplary embodiment. The closure element is designed similarly to the closure element 110a, that is to say has depressions 121b, 122b, 121b ', 122b', the width of which is essentially constant, so that a rectangular closure surface opening results. The flow resistance, which changes along the direction B, is also here essentially achieved by a depth of the depression that changes along the direction B. Here, the recesses are distributed in pairs in the direction B one behind the other around a cylindrical section of the closure element 110b or its single cylindrical closure surface 120b. A pair of recesses can be aligned by the user by rotating the closure element 110b at the first and second chamber openings, the rotational position of the closure element in this alignment preferably being secured by a latching device (not shown).

Fig. 3d shows the closure element 110c which can be used in the pipetting device according to the invention by further adapting the arrangement of the chamber openings, according to a fourth exemplary embodiment. The closure element has the cylindrical section with a cylindrical closure surface 120c. A turn towards B A tapering first recess 121c serves to open the pipetting channel, a second recess 122c (not visible) which widens in direction B and which is opposite recess 121c serves to simultaneously close the bypass channel when moving in direction B. The first and second chamber openings are corresponding the position of the depressions 121c and 122c opposite arranged on the valve chamber (not shown). Another pair of recesses 121c 'and 122c' (not visible) can be adjusted by the user by rotating the closure element 110c.

Figure 3e shows the closure element 110d which can be used in the pipetting device according to the invention by further adapting the arrangement of the chamber openings, according to a fifth exemplary embodiment. It differs from the closure element 110c only in the maximum depth of the depth of one, several or all of the depressions, which changes along the direction B.

Different fastener elements, e.g., fastener element 110c and fastener element 110d, may preferably be used with the same fastener carrier element.

Claims (11)

1. A pipetting apparatus (7), in particular for pipetting a fluid sample (9a) by suctioning into a pipetting container (9) using air (9b) under a pipetting pressure, comprising:

   - a valve assembly having at least one valve device (101) for adjusting a pipetting pressure,

   - wherein the valve device comprises a valve chamber (106);

   - at least one pump device (7) connected to the valve chamber in order to generate a chamber pressure in said valve chamber;

   - a pipetting channel (103) connectable to the pipetting container and

   - a bypass channel (104) which is open to the surroundings;

   wherein the valve chamber has a first chamber opening (113) connected to the pipetting channel and a second chamber opening (114) connected to the bypass channel,
   wherein the valve device comprises a closure element (110; 110a; 11 0b; 110c; 110d) at least partially disposed within the valve chamber, which can be moved relative to the valve chamber by a user-controlled movement (B) and which comprises at least one closure surface (120; 120a; 120b; 120c; 120d), which is an essentially planar surface lying in one plane, or which is a surface with a non-planar shape, described by the translation or rotation of a circular shape, an ellipse or a polygon and wherein the closure surface slides along said chamber openings parallel to the first and parallel to the second chamber opening during the movement in contact with the respective chamber opening and closes them as a function of the position of the closure surface, wherein the first and/or the second chamber opening or a sealing section connected to said chamber opening comprises a respective opening edge lying essentially in the same plane or bordering the same, and wherein the at least one closure surface is formed, such that in order to generate the desired pipetting pressure in the pipetting channel, the chamber pressure is distributed to the pipetting channel and the bypass channel in dependency of the position of the at least one closure surface at the first and second chamber opening.
2. The pipetting apparatus according to claim 1, wherein the closure element comprises at least one recess (121; 122; 121a; 122a; 121b; 122b; 121c; 122c; 121d; 122d), which extends from the closure surface into the depth of the closure element and forms at least one closure surface opening in the closure surface,
   wherein said at least one closure surface opening comprises a length measured parallel to the direction of the movement (B) and a width measured perpendicular thereto,
   wherein the width of the at least one closure surface opening and/or the depth of the at least one recess varies at least sectionally in the direction of this movement, and
   in particular the closure surface with the at least one closure surface opening slides along the first and/or second chamber opening such that the closure cross section of the first and/or second chamber opening varies during the movement.
3. The pipetting apparatus according to claim 1 or 2, wherein the closure element comprises a first recess (121; 121a; 121b; 121c; 121 d) which extends from the closure surface into the depth of the closure element and forms a first closure surface opening in the closure surface, and wherein the closure element comprises a second recess (122; 122a; 122b; 122c; 122d) which extends from the closure surface into the depth of the closure element and forms a second closure surface opening in the closure surface,
   wherein during the movement, the first closure surface opening lies against the first chamber opening and the second closure surface opening lies against the second chamber opening.
4. The pipetting apparatus according to claim 3, wherein the width of the first closure surface opening and/or the depth of the first recess increases at least sectionally in the direction of this movement and wherein the width of the second closure surface opening and/or the depth of the second recess decreases at least sectionally in the direction of this movement.
5. The pipetting apparatus according to one of the preceding claims, wherein the first chamber opening and the at least one closure surface define a first connecting channel with a variable first flow resistance R1, wherein said first connecting channel connects the pipetting channel to the valve chamber, and wherein the second chamber opening and the at least one closure surface define a second connecting channel with a variable second flow resistance R2, wherein said second connecting channel connects the bypass channel to the valve chamber, wherein the distribution of the chamber pressure on the pipetting channel and the bypass channel changes the R2/R1 ratio, wherein in particular the ratio increases during the movement.
6. The pipetting apparatus according to one of the preceding claims, wherein the closure element comprises at least one first closure surface and one second closure surface which are not parallel and in particular oriented at an angle of 60°<=α<=120° to each other.
7. The pipetting apparatus according to claim 6, wherein during this movement the first closure surface is positioned opposite the first chamber opening and slides along same and the second closure surface is positioned opposite the second chamber opening and slides along same during the movement.
8. The pipetting apparatus according to one of the preceding claims, wherein the first and/or second chamber opening comprises a sealing section, which is contacted by the at least one closure surface, in particular to seal the first and/or second chamber opening in essentially completely gas-tight manner in at least one position of the closure element.
9. The pipetting apparatus according to one of the preceding claims, wherein the valve chamber or the closure element comprises at least one sealing section in order to seal the valve chamber in essentially completely gas-tight manner in at least one position of the closure element and/or during the movement.
10. The pipetting apparatus according to at least one of the preceding claims, comprising a first valve device having a first valve chamber and a second valve device having a second valve chamber, wherein the pump device is connected to the first valve chamber in order to generate a first chamber pressure in said first valve chamber and connected to the second valve chamber in order to generate a second chamber pressure in said second valve chamber, wherein the first valve chamber and the second valve chamber are in each case connected to the pipetting channel and the bypass channel,
    wherein the first valve device is configured, such that a pressure is set in the pipetting channel for suctioning a fluid sample into a pipetting container, which is air-tight connected to the pipetting channel, and
    wherein the second valve device is configured, such that a pressure is set in the pipetting channel for dispensing a fluid sample from a pipetting container, which is air-tight connected to the pipetting channel.
11. A method for producing the pipetting apparatus according to one of claims 1 to 10, comprising the steps:

    - producing the at least one valve device of the valve assembly at least partly from a first material;

    - producing at least one closure element;

    - producing the at least one pipetting channel, and in particular also the at least one bypass channel, at least partly from a second material.

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