EP2319623A2 - Metering device for liquids and method for metering liquids - Google Patents

Abstract

The metering device comprises a base body (2) and a pipette tip (6) with its upper opening in a sealing connection with a through opening (15) at the base body. The displacement equipment (12) is arranged in the base body, where a displacement chamber (13) is arranged in a displacement device (14). A syringe piston is displaced to a syringe cylinder, where a coupling unit is connected with the syringe piston in the base body. An independent claim is also included for a method for dosing of liquids.

Description

The invention relates to a metering device for liquids with means for holding a pipette tip or syringe and means for releasing the pipette tip or syringe and with an electric drive motor for moving a displacement member of a displacing means for sucking or expelling air into or out of a pipette tip or for moving of couplable with a syringe plunger of the syringe coupling means. In this case, the means for releasing the pipette tip or syringe are actuated separately without the displacement element or the syringe piston and the coupling means coupled with it being moved. Furthermore, the invention relates to a method for dosing liquids by means of such Dosiervornchtung.

Dosing devices are mainly used in the laboratory for dosing liquids. The amounts of liquid to be metered are in particular in the range of 100 nl to a few 100 ml settled. Dosing devices, with which liquid is taken up in a single step and delivered in a single step, are called pipettes. Dosing devices, with which liquid is taken up in a single or several steps and dispensed in several steps, is called a dispenser.

The liquids are taken up in pipette tips or syringes and discharged from it. Pipette tips are small tubes with an opening at the bottom and an opening at the top. The lower opening is usually smaller than the upper opening. Syringes have a syringe barrel and a syringe plunger movably mounted in the syringe barrel by displacement in the direction of the barrel axis. Furthermore, the syringe barrel in the syringe bottom has a Syringe opening, which is often located in a small tube protruding from the syringe bottom.

The pipette tip is held on the dosing device during dosing, so that the upper opening is in communicating connection with a displacement device of the dosing device. The displacement device is usually a cylinder with a piston displaceable therein. By moving the plunger, an air cushion is displaced so that liquid is drawn in or out of the pipette tip through the lower opening.

The syringe is held on the metering device so that the syringe barrel is immovably coupled with respect to the metering device and the syringe plunger with coupling means of the metering device is mechanically coupled. By displacing the coupling means, the syringe plunger can be displaced in the syringe barrel to draw liquid into and out of the syringe barrel.

For moving the displacing member or the coupling means, known metering devices comprise a manually driven drive mechanism or an electric drive motor. A metering device with an electric drive motor is controlled by means of electrical control means and has an electrical power supply connected to the electrical control means and the electric drive motor (eg battery, battery or power supply). The electrical control means are also electrically connected to input means. By means of the input means, metering steps (eg, intake and delivery of liquid) can be controlled and / or the quantities of liquids to be picked up and dispensed can be selected and / or operating modes (eg, pipetting or dispensing) can be selected. The input means may in particular electrical buttons or Be a switch. Furthermore, dosing devices with an electric drive motor often have a display device (eg an LCD display) for outputting information about the operating state of the dosing device and / or the progress of a dosing procedure and / or selected dosing quantities and / or a selected operating mode.

The means for holding the pipette tip are mostly guided as a press fit (e.g., clip-on or blind bore). A passage opening in the front side of the attachment lug or in the bottom of the blind bore communicates with the displacement chamber of the displacement device.

The means for holding the syringe are, for example, cylinder gripping levers, which are associated with a cylinder receptacle in a housing of the metering device, in order to hold a flange on the syringe cylinder in the cylinder receptacle. Further, the means for holding may include piston gripping levers in a clutch bell into which a radially-protruded end of the syringe plunger or a syringe piston rod may be inserted to couple it to the clutch bell.

Pipette tips and syringes are detachably connected to the dosing device so that they can be replaced after use for fresh pipette tips or syringes. As a result, contamination can be avoided at subsequent dosages. Single-use pipette tips or syringes are available inexpensively from plastic.

The means for releasing a pipette tip in many cases comprise a Abwerfschieber having an end which is associated with the attachment lug or the blind bore. The other end of the discharge slide has an actuating button. By Relocating the Abwerfschiebers a pipette tip can be pushed off the attachment lug or pushed out of the blind bore.

Here, the means for releasing the pipette tip or syringe is preferably arranged on the outside of the body side and is not in communication with the displacement member of the displacement means, usually the cylinder, or the movable coupling means of the metering device when syringes are used.

To release the syringe, the gripping levers can be pivoted outwards. For this purpose, the Zylindergreifhebel may be provided with manually operable from the outside operating ends and having on the inside contact points which cooperate with actuating ends of the piston gripping lever, so that upon actuation of the Zylindergreifhebel the piston gripping levers are actuated when the syringe barrel is fully inserted into the syringe plunger. The means for releasing a syringe may also comprise a mechanism which is actuated by means of a single actuating knob and acts on the Zylindergreifhebel and the piston gripping lever. In particular, irrespective of the position of the syringe plunger in the syringe barrel, the means for releasing the syringe can cause the syringe to be detached from the metering device.

In the metering device with electric drive motor, the release of a pipette tip has no effect on the positioning of the piston in the cylinder of the displacement device. For example, if the dropping of the pipette tip occurs when the piston is in an upper position after the intake stroke, the piston must be displaced to a home position by additional actuation steps, from which a new complete metering operation can be started. If a metering device with an electric Drive motor after the release of the pipette tip with the piston in its upper position and then used by another person, there may be difficulties if this person does not recognize that the piston for the dosage must first be brought to a lower position to liquid with the dosing record.

In general, it is not clear for the user of a metering device with controllable, in particular electric drive, in which position the actuating member or the coupling means is located when he has dropped the pipette tip or syringe of the metering device.

In a metering device, there is also the situation where the user wishes to discard a pipette tip or syringe, although a picked up liquid or liquid-entrained particles such as magnetic beads are at least partially still in the pipette tip or syringe. In this case, the displacer or the coupling means is not moved down and yet the pipette tip or syringe with the separate means of dislodging device or the coupling means for releasing the pipette tip or syringe is dropped. Since in this situation after the drop for the next user of the metering device, especially if it is different from the one who has previously used the metering device, the position of the displacement member or the coupling means is unknown, he knows after placing a new pipette tip or Do not insert a syringe, whether it must first move the displacer or the coupling means down to receive liquid with the metering device or whether the displacer or the coupling agent are already below. Corresponding problems can occur when a syringe is released in a metering device with electric drive motor before the syringe plunger and thus the coupling agent has been brought into its lower position.

The US Pat. No. 6,968,749 B2 discloses a portable automatic pipette with pipette tip ejector. A sensor detects if a pipette tip has been removed. When the sensor detects the removal of a pipette tip, a microprocessor controls the output of an alarm to alert the user that a misoperation has occurred. For a new dosing process, the user must reset the pipette to the initial state.

The solutions mentioned below from the following documents can also be used in the metering device according to the invention and the method according to the invention. The related description is incorporated by reference into the present application.

From the US 5,187,990 a metering device for pipette tips with an electric drive and a disposer for pipette tips is known. From this document, electrical control means for controlling the displacement of the plunger of the displacing means and a method for metering liquids are known in which the plunger is displaced in a special way.

The US Pat. No. 6,778,917 B1 . US 2007/0276546 A1 and US 2008/0011042 A1 disclose devices with electrical control means, input means and display devices. From these documents, special controls as well as input and display methods are known.

The US Pat. No. 7,434,448 B2 describes a metering device with a dropper for pipette tips. It is also known from this document that the housing of the pipette has an upper housing part with a drive mechanism and a lower housing part detachably connectable with a displacement device. A plate on a piston rod of the piston is pressed under spring tension against the end of a drive rod of the drive mechanism.

From the US 2008/0006100 A1 a metering device with a housing top and a housing lower part and a coupling between the piston and the drive mechanism is known, which comprises an elastic element.

The US 5,620,660 describes a metering device with Zylindergreifhebeln and piston gripping levers for releasably holding syringes.

Based on this, the object of the invention is to provide a metering device for liquids and a method for metering liquids, which facilitates the implementation of a further metering after the release of a pipette tip or syringe.

The object is achieved by a metering device with the features of claim 1. Advantageous embodiments of the metering device are specified in subclaims.

• einen Grundkörper,
• am Grundkörper angeordnete Mittel zum Halten mindestens einer Pipettenspitze mit ihrer oberen Öffnung in abdichtender Verbindung mit einer Durchgangsöffnung am Grundkörper und eine im Grundkörper angeordneten Verdrängungseinrichtung mit einer Verdrängungskammer, einem darin beweglich angeordneten Verdrängungsorgan und einer kommunizierenden Verbindung mit der Durchgangsöffnung oder
• am Grundkörper angeordnete Mittel zum Halten mindestens einer Spritze mit einem Spritzenzylinder in lagefester Beziehung zum Grundkörper und mit einem im Spritzenzylinder verschiebbaren Spritzenkolben in Wirkverbindung mit Kupplungsmitteln im Grundkörper,
• am Grundkörper angeordnete Mittel zum Lösen der Pipettenspitze oder Spritze von den Mitteln zum Halten mit einem manuell betätigbaren Betätigungsorgan zum Betätigen der Mittel zum Lösen, ohne dass dabei das Verdrängungsorgan oder das Kupplungsmittel bewegt werden,
• einen am Grundkörper angeordneten Sensor zum Erfassen einer Betätigung der Mittel zum Lösen oder des erfolgten Lösens der Pipettenspitze oder Spritze,
• einen ansteuerbaren Antrieb, der mit dem Verdrängungsorgan oder den Kupplungsmitteln wirkverbunden ist,
• Eingabemittel zum Steuern des ansteuerbaren Antriebs,
• elektrische Steuerungsmittel, die mit dem ansteuerbaren Antrieb, den Eingabemitteln und dem Sensor elektrisch verbunden sind und die so beschaffen sind, dass der ansteuerbare Antrieb, wenn der Sensor eine Betätigung der Mittel zum Lösen oder das erfolgte Lösen der Pipettenspitze oder Spritze erfasst, das Verdrängungsorgan oder die Kupplungsmittel in eine Grundposition verlagert.

The dosing device for liquids has

• a basic body,
• arranged on the main body means for holding at least one pipette tip with its upper opening in sealing engagement with a through-opening on the base body and a displacement device arranged in the base body with a displacement chamber, a displacement element arranged movably therein and a communicating connection with the passage opening or
• arranged on the main body means for holding at least one syringe with a syringe barrel in positionally stable relationship to the base body and with a syringe barrel displaceable in the syringe barrel in operative connection with coupling means in the body,
• means for releasing the pipette tip or syringe arranged on the main body from the means for holding with a manually actuatable actuating member for actuating the means for releasing, without the displacement element or the coupling means being moved,
• a sensor arranged on the base body for detecting an actuation of the means for releasing or for loosening the pipette tip or syringe,
• a controllable drive, which is operatively connected to the displacement member or the coupling means,
• Input means for controlling the controllable drive,
• electrical control means electrically connected to the drivable drive, the input means and the sensor and arranged to cause the drivable actuator, when the sensor detects actuation of the means for disengaging or disengaging the pipette tip or syringe, to comprise the displacer or shifting the coupling agent to a basic position.

Preferably, from the basic position, a displacement of the displacement member or the coupling means for receiving liquid in a pipette tip or syringe.

The controllable drive is preferably an electric drive, in particular an electric drive motor.

The metering device according to the invention has a base body, which is a supporting structure for further components of the metering device. The main body is for example a housing. There are means on the main body for holding at least one pipette tip or syringe. The metering device can therefore be designed as a single-channel or as a multi-channel metering device. The means for holding at least one pipette tip may be a clip-on lug or a blind bore. The means for holding at least one syringe may include cylinder gripping levers and piston gripping levers.

The means for holding at least one pipette tip are present in combination with a displacement device with a displacement chamber and a displacement member. The means for holding at least one syringe include coupling means which are mechanically coupled to the syringe plunger. The coupling means may in particular be a clutch bell with piston gripping levers.

There are also means for releasing the pipette tip or syringe. These are separate from the displacement device and the coupling agent. The means for releasing a pipette tip are preferably designed as Abwerfschieber which is arranged and arranged so that it pushes a pipette tip of a press fit, when the actuator connected to the Abwerfschieber is actuated. The means for releasing a syringe have, for example, a mechanism that is in operative connection with Zylindergreifhebeln and piston gripping levers.

The actuation of the means for releasing is detected by a sensor which is arranged on the base body. Electric control means controls the driveable actuator to displace the displacer or coupling means to a home position when the sensor detects actuation of the disengagement means. The basic position can be chosen arbitrarily on the way, can be moved on the displacement member or coupling agent in the metering device. The home position is preferably the position from which a displacement of the displacer or the coupling means is always upward when the intake of liquid into a fresh pipette tip or syringe is intended. The sensor detects that the means for releasing have been actuated. This indirectly detects that no pipette tip or syringe is held on the metering device. The signal from the sensor is used by the control means to drive the displacer or coupling means to the home position. As a result, in this preferred embodiment, immediately after releasing the pipette tip or syringe, the metering device is again ready to receive liquid into a new pipette tip or syringe.

The basic position may, however, also be at the top, for example, so that the displacing member or coupling agent first has to be moved downwards before picking up a liquid. This can either be done automatically if the user gives a command to the dosing device to take up liquid by means of the input means. On the other hand, however, the user may also have to give an instruction to the dosing device to drive the displacement means or the coupling means downwards before picking up a liquid by input means.

As a result, the operation of the metering device is facilitated for the user. The user is particularly protected against incorrect filling of the pipette tip or syringe and other errors.

Alternatively, the sensor disposed on the main body can also detect the disengagement of a pipette tip or syringe, e.g. in which he states that the sealed connection between the pipette tip and the means arranged on the main body for holding no longer exists.

The sensor may, for example, be a switch actuated by the means for releasing when the actuator is confirmed. In particular, this may be a switch which is arranged in the displacement region of the actuating member. According to a further embodiment, the sensor is a reed contact, which can be actuated by displacement of a magnet arranged on the means for releasing. The magnet is preferably a permanent magnet. According to a further embodiment, the magnet is arranged on the actuating member. According to a further embodiment, the reed contact is arranged on a circuit board in the main body. In particular, the board may be a board comprising the electrical control means or a part thereof.

In general, it is also possible to use as a sensor any other sensor which detects the movement of the actuator or of the means for releasing the pipette tip or syringe. In this case, the sensor detects the operation of the means for releasing in a position of the actuator or means for releasing, in which it is ensured that the pipette tip or syringe has been dropped.

According to one embodiment, the sensor is responsive to an actuation of the means for releasing when the displacement of the actuator at least the Displacement path of the actuator, which must be returned for releasing the pipette tip or syringe from the means for holding. According to a further embodiment, the displacement path for actuating the sensor is 3.6 to 4.5 mm, preferably 4 mm, and the displacement path for releasing the pipette tip or syringe 2.5 to 3.5 mm, preferably 3.1 mm.

According to a further embodiment, the means for holding at least one clamping seat for a pipette tip and the means for releasing a movable relative to the clamping seat Abwerfschiebers with one end for pressing a pipette tip from the clamping seat and the actuating member at the other end.

According to a further embodiment, the displacement chamber is a cylinder and the displacement member is a piston arranged displaceably within the cylinder.

According to a further embodiment, the control means are arranged to, when the sensor detects an actuation of the means for releasing displace the displacing member to a home position, from which the extent of further displacement of the displacing member is determined, and the displacement member after reaching shift the home position to the home position. The home position (also called "home position") serves to set the metering device to a defined starting position. From the home position, the displacements of the repressive organ are determined. This ensures that the extent of the displacement of the displacement element and thus the dosing accuracy can be controlled very accurately. This is particularly advantageous if the electric drive motor is a DC motor whose rotation is determined by means of a rotary encoder. The Experience has shown that in this case individual counts can be lost, whereby the accuracy of the displacement of the displacing organ is impaired over time. By positioning the displacement element in a home position, the metering device is brought into a defined starting position, which is the starting point for the further displacement of the displacement element. Intermediate counting errors are thereby eliminated. This embodiment may also be useful in other embodiments of the electric drive motor, for example in an embodiment as a stepper motor.

According to a preferred embodiment, the control means are arranged so that they control a movement of the displacement member in the home position and then in the home position when switching on the metering device. As a result, it is ensured each time the dosing device is switched on that the displacement of the displacement element takes place from a defined starting position.

Alternatively, the home position may already be the basic position into which the displacement element or the coupling means are displaced.

The home position can be realized, for example, in that the displacement element or an associated drive mechanism encounters a stop. This can lead to blockages in the drive system, increased power consumption and material damage. According to a preferred embodiment, a further sensor arranged in the main body, which is electrically connected to the control means, detects the reaching of the home position by the displacement member. The above-described disadvantages of a home position defined by a stop are thereby overcome. According to a further embodiment, the further sensor is a Hall sensor, the one with the displacer associated further magnet is actuated when the displacer reaches the home position. The further magnet can also be connected indirectly to the displacement member, for example by being fixed to a drive mechanism which drives the displacement member.

According to one embodiment, the home position is 1 to 8 mm away from the home position, preferably 4 mm.

According to one embodiment, the control means are such that, starting from the basic position, they control an intake stroke of the displacement member, then at least one blow-out stroke until the basic position is reached by the displacement member and thereafter an overblow stroke until a blow-over position is reached. The Überblasposition serves to remove residual amounts of liquid from the pipette tip. The blow-over position is preferably arranged between the basic position and the home position. For example, it has a distance of 1.0 to 3.9 mm from the home position, in particular 3 mm. The fact that the Überblasposition has a distance from the home position, the displacer can be moved very quickly in the Überblasposition to blow liquid from the pipette tip. Furthermore, the displacement member can be moved very slowly and thus exactly in the home position. In principle, it is also possible that Überblasposition and home position coincide.

In the metering device, which has means for holding at least one syringe, a defined initial position is given by the fact that the syringe piston impinges on the bottom of the syringe barrel. This impact is also desirable so that an air cushion between the syringe plunger and liquid is avoided. As a result, it is dispensable in this type of metering device, the Shifting agent and thus the syringe plunger in a home position. In this type of metering device, the metering operations thus preferably take place starting from a basic position in which the syringe piston is seated on the bottom of the syringe barrel.

The metering device is preferably a manageable metering device. Preferably, in the manageable metering device, the housing is designed as a handle. However, the metering device can also be designed as a stationary metering device. It is also possible to design the metering device so that it can be used as a manageable metering device and as a stationary metering device.

Furthermore, the object is achieved by a method having the features of claim 12. Advantageous embodiments of the method are specified in subclaims.

• eine Betätigung der Mittel zum Lösen oder das erfolgte Lösen der Pipettenspitze oder Spritze erfasst und
• nach einer Betätigung der Mittel zum Lösen das Verdrängungsorgan oder die Kupplungsmittel in eine Grundposition verlagert.

In the method according to the invention for dosing liquids by means of a dosing device with means for holding at least one pipette tip and a displacement device with a displacement chamber and a displaceable therein movably or with means for holding a syringe with a syringe barrel and a syringe piston displaceable therein and with the syringe plunger detachable Coupling means and an operatively connected to the displacement member or the coupling means controllable drive and means for releasing the pipette tip or syringe from the means for holding is

• an actuation of the means for releasing or the disengagement of the pipette tip or syringe is detected and
• displaced after actuation of the means for releasing the displacing member or the coupling means in a basic position.

Preferably, the displacement element or the coupling agent for receiving liquid is then displaced from the basic position into the pipette tip or syringe.

For this method, the advantageous effects described for the metering apply.

According to one embodiment of the method, the displacement element is first moved to a home position and then to a basic position. As already described, this embodiment serves to carry out the metering operations from a defined starting point. For this purpose, according to a further embodiment, the displacement member when switching the metering device initially moved to the home position and then to the home position.

Finally, according to one embodiment, the displacement member for receiving liquid in the pipette tip from the basic position by at least one intake stroke, then shifted by at least one Ausblashub until reaching the home position and then by an Überblashub until reaching the Überblasposition.

Fig. 1a

eine Dosiervorrichtung mit aufgesteckter Pipettenspitze in Arbeitsposition, wobei sie im Bereich des Betätigungsorganes und im Bereich der Verbindung zweier Abschnitte der Abwerfeinrichtung vertikal geschnitten ist;

Fig. 1b

eine mögliche Ausgestaltung des Gehäuseunterteils der Dosiervorrichtung von Fig. 1a;

Fig. 2

vergrößerter Schnitt II von Fig. 1a;

Fig. 3

vergrößerter Schnitt III von Fig. 1a;

Fig. 4

dieselbe Dosiervorrichtung mit der Abwerfeinrichtung in Abwurfposition in Seitenansicht, wobei die Abwurfeinrichtung an denselben Stellen wie in Fig. 1 vertikal geschnitten ist;

Fig. 5

vergrößerter Schnitt V von Fig. 4;

Fig. 6

vergrößerter Schnitt VI von Fig. 4;

Fig. 7

dieselbe Dosiervorrichtung mit dem Antrieb in Heimatposition in Seitenansicht, wobei sie im Bereich des Antriebsvertikal geschnitten ist;

Fig. 8

vergrößerter Schnitt VIII von Fig. 7;

Fig. 9

dieselbe Dosiervorrichtung mit dem Antrieb in Grundposition in Seitenansicht, wobei sie im Bereich des Antriebs vertikal geschnitten ist;

Fig. 10

vergrößerter Schnitt IX gemäß Fig. 9;

Fig. 11

dieselbe Dosiervorrichtung mit dem Antrieb in der oberen Position in Seitenansicht, wobei sie im Bereich des Antriebs vertikal geschnitten ist;

Fig. 12a

vergrößerter Schnitt XII von Fig. 11;

Fig. 12b

ein Fig. 12a entsprechender Schnitt einer alternativen Ausführung der Dosiervorrichtung;

Fig. 13

dieselbe Dosiervorrichtung mit dem Antrieb in Arbeitsposition mit aufgesteckter Pipettenspitze bei teilweise geöffnetem Gehäuse in perspektivischer Ansicht schräg von der Seite;

Fig. 14

Detail XIV von Fig. 11;

Fig. 15

vergrößertes Detail XV von Fig. 11.

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

Fig. 1a

a metering device with attached pipette tip in the working position, wherein it is cut vertically in the region of the actuator and in the region of the connection of two sections of the ejection device;

Fig. 1b

a possible embodiment of the lower housing part of the metering device of Fig. 1a ;

Fig. 2

enlarged section II of Fig. 1a ;

Fig. 3

enlarged section III of Fig. 1a ;

Fig. 4

the same metering device with the ejector in discharge position in side view, wherein the discharge device at the same locations as in Fig. 1 is cut vertically;

Fig. 5

enlarged section V of Fig. 4 ;

Fig. 6

enlarged section VI of Fig. 4 ;

Fig. 7

the same metering device with the drive in home position in side view, wherein it is cut in the region of the drive vertically;

Fig. 8

enlarged section VIII of Fig. 7 ;

Fig. 9

the same metering device with the drive in basic position in side view, wherein it is cut vertically in the region of the drive;

Fig. 10

enlarged section IX according to Fig. 9 ;

Fig. 11

the same metering device with the drive in the upper position in side view, wherein it is cut vertically in the region of the drive;

Fig. 12a

enlarged section XII of Fig. 11 ;

Fig. 12b

one Fig. 12a corresponding section of an alternative embodiment of the metering device;

Fig. 13

the same metering device with the drive in working position with attached pipette tip with partially open housing in a perspective view obliquely from the side;

Fig. 14

Detail XIV of Fig. 11 ;

Fig. 15

enlarged detail XV of Fig. 11 ,

In the present application, the terms "top", "bottom", "horizontal", "vertical" refer to the orientation of the metering device as shown in the figures. According to the drawings, a pipette tip held on the metering device is arranged with its lower opening at the bottom to receive liquid from a vessel located below the metering device or to discharge it into such a vessel.

The metering device 1 has an elongated, designed as a handle housing 2 with an upper housing part 2.1 and a lower housing part 2.2. The upper housing part 2.1 has input means 3 in the form of a rocker switch 3.1 and two buttons 3.2, 3.3 and a mode rotary switch 3.3. Furthermore, at the Housing top 2.1 a display device 4 arranged in the form of an LCD display.

The lower housing part 2.2 has at the lower end a conical clamping seat 5 for attaching a pipette tip 6.

Furthermore, the metering device has means for releasing 7 the pipette tip 6 from the clamping seat. These means for releasing 7 include a Abwerfschieber 7.1, which has a sleeve-shaped slide part 7.2, which is arranged on the lower housing part 2.2 and from an upper abutment position on the upper housing part 2.1 from below to be displaced. The Abwerfschieber 7.1 comprises a rod part 7.3, which is guided in a vertical guide channel in the upper housing part 2.1. The rod part 7.3 is connected at the upper end with an actuator 7.4 in the form of an actuating knob which is actuated from the outside. Contrary to the action of a return spring 8, which is supported at the top of a projection on the rod part 7.3 and is supported at the bottom of the top of a housing-fixed abutment 9, the Abwerfschieber 7.1 by pressing the actuator 7.4 is displaced downwards. The movement of Abwerfschiebers 7.1 upwards is limited by an O-ring 10 which is partially inserted into an annular groove 11 at the lower end of the rod member 7.3 and rests in the uppermost position on the underside of the abutment 9.

In the lower housing part 2.2, a displacement device 12 is arranged with a displacement chamber 13 in the form of a cylinder and a displaceable member 14 movably arranged therein in the form of a piston. The displacement chamber 13 is connected via a passage 14.1 with a passage opening 15 in the lower end face of the clamping seat fifth communicatively connected. The above features of the housing base 2.2 are in Fig. 1a shown.

Fig. 1b shows a detailed embodiment of the housing lower part 2.2, which can be used in the metering device 1. The above reference numerals are in Fig. 1b entered. The lower housing part 2.2 is in the German patent application DE 10 2008 048 252.8 and the US Provisional 61/097393 described. The related description is incorporated by reference into the present application.

In the housing 2, a sensor 16 is fixed in the form of a reed contact. The reed contact is associated with a magnet 17, which is designed as a cylindrical permanent magnet and is fixed at the upper end of the rod part 7.3 of Abwerfschiebers 7.1.

The sensor 16 is seated on the lower board portion 18.1 of a board 18, which has three with respect to each other angled platinum parts. On the central board part 18.2 it carries components of electrical control means 19, which are implemented in semiconductor technology. Furthermore, there are the rocker switch 3.1 and the buttons 3.2, 3.3 are arranged. The upper board part 18.3 carries the display device 4 and the mode rotary switch 3.3. The reed contact is wired to the electrical control means 19.

In the upper housing part 2.1, an electric drive motor 20 is arranged. The drive motor 20 is a DC motor. The drive motor 20 is arranged vertically with the shaft 21 at the lower end. The shaft 21 carries a drive pinion 22. Below the drive pinion 22, the shaft 21 carries in a bell-like socket 23 a Drehwinkelgeber-magnet 24. This is a permanent magnet, which is designed as a bar magnet.

Below the rotary encoder 24 is arranged on a further circuit board as an IC rotary encoder 25 is arranged.

The rotary encoder 25 is wired to electrical control means 19.

In addition to the drive motor 20, a vertically aligned spindle 26 is arranged in the upper housing part 2.1. The spindle 26 extends through a spindle nut 27 having a gear 28 on the outside. The spindle nut 27 is mounted on both sides in ball bearings 29.1, 29.2.

The spindle 26 has at the top a radial projection 30 which is guided in an axially extending groove 31 of a spindle 26 parallel to the housing, fixed guide 32. The projection 30 thus forms an anti-rotation of the spindle 26th

Via the drive pinion 22 and the gear 28, a toothed belt 33 is guided. When the shaft 21 of the drive motor 20 rotates, the spindle nut 27 is driven via the drive pinion 22 and the toothed belt 33. As a result, the spindle 26 is screwed within the spindle nut 27. Since the spindle 26 is prevented by the engagement of the projection 30 in the groove 31 from twisting, in this case, the spindle 26 moves upward or downward, depending on the direction of rotation of the shaft 21st

Furthermore, a further magnet 34 is positioned in the spindle 26 next to the projection 30. This is also a permanent magnet, which is designed as a bar magnet.

In addition to the spindle 26, a Hall sensor 36 is arranged in the upper housing part 2.1 on a further board 35. The Hall sensor 36 is also connected to the electrical control means 19. The spindle 26 is adjustable so that the further magnet 34 comes into the sphere of influence of the Hall sensor 36.

The spindle 26 carries at the lower end of a magnetic disk 37th

The displacement member 14 carries a piston rod 38 at the top, which carries a further magnetic plate 39 at the upper end. The magnetic discs 37, 39 of the spindle 26 and the piston rod 38 have different poles on the sides facing each other so that they adhere to each other when they are brought into contact. For this purpose, the further magnetic disk 38 can be pressed by a arranged in the lower housing part 2.2 spring 38.1 up to an upper stop 38.2 upwards. The magnetic disk 37 is inserted through a hole 38.3 in the stop 38.2 through the magnetic disk 39.

Instead, contribute to the alternatives of Fig. 12b the piston rod 38 at the upper end of a dish washer, which is pressed by a arranged in the lower housing part 2.2 spring 38.1 up to an upper stop 38.2 upwards. The lower end face of the spindle 26 can abut through a hole 38.3 in the stopper 38.2 through the washer 39.1, so that the spindle 26, the piston rod 38 and thus the piston against the action of the spring can shift down. When the spindle 26 is displaced upward, the piston rod 38 and thus the piston is pushed back by the spring upwards.

According to Fig. 1 to 3 is a pipette tip 6 attached to the clamping seat 5 and the Abwerfschieber 7.1 not operated. In this configuration, the dosing device 1 is ready for a dosing process.

According to FIGS. 7 and 8 the spindle 26 is in a home position, in which the further magnet 34 is associated with the Hall sensor 36. The electrical control means 19 controls the drive motor 20 so that the spindle 26 is brought into this position when the metering device 1 is turned on, by pressing an on / off switch, not shown.

The pulses of the rotary encoder 25 are counted by the electrical control means 19, starting from the home position in the home position. The displacement of the spindle 26 is thus related to the home position.

After reaching the home position, the electrical control means 19 automatically controls the drive motor 20 so that the spindle 26 is displaced to a home position which is slightly above the home position. From the basic position, dosing operations are started in all operating modes, for example pipetting or dispensing. The basic position is in the example 4 mm above the home position. This is in the FIGS. 9 and 10 shown.

Corresponding to a predetermined by the input means 3 Dosiermenge control the electrical control means 19, the displacement of the spindle 26 by a distance upwards. As a result, the piston in the displacer 12 is moved upward and liquid is sucked into the pipette tip 6. The spindle 26 is in its uppermost position for receiving a certain amount of liquid in the FIGS. 11 and 12 shown.

The displacement of the spindle 26 from the basic position upward for carrying out a suction stroke is controlled by operating the switching rocker 3.1.

After reaching the top position is triggered by re-confirming the rocker switch 3.1, that the electrical control means 19, a displacement of the spindle 26 down to the basic position according to FIGS. 9 and 10 Taxes. In this case, liquid is dispensed from the pipette tip 6.

By re-pressing the rocker switch 3.1, the execution of a Überblashubes is triggered. Here, the electrical control means 19, the spindle 26 displace by a stroke of 3 mm down quickly, so that residual liquid from the pipette tip 6 is pressed out.

Thereafter, by pressing the actuator 7.4, the pipette tip 6 are dropped. After the actuator 7.4 has traveled a distance of 3.1 mm down, sits the sleeve-shaped sliding part 7.2 with the lower end face on the upper edge of the pipette tip 6 and pushes them from the clamping seat 5 from. After the actuator 7.4 is moved down by a total of 4 mm, the sensor 16 is actuated by the magnet 17. This gives the electronic control means 19 a signal which triggers that the electronic control means 19 drive the drive motor 20 so that the spindle 26 again in the home position of FIGS. 7 and 8 and immediately afterwards automatically to the basic position of FIGS. 9 and 10 arrives.

After discharge of the actuator 7.4, the metering device 1 is ready for receiving a further pipette tip 6. The inclusion of a further pipette tip 6 takes place by inserting the clamping seat 5 in the upper opening of the pipette tip. 6

Claims (14)

Dosing device for liquids with a base body (2), - On the base body (2) arranged means for holding (5) at least one pipette tip (6) with its upper opening in sealing connection with a passage opening (15) on the base body (2) and in the base body (2) arranged displacement means (12) a displacement chamber (13), a displaceable member (14) movably disposed therein and a communicating connection with the passage opening (15) or - arranged on the base body (2) means for holding at least one syringe with a syringe barrel in a positionally fixed relationship to the body and with a displaceable in the syringe barrel syringe plunger and a mechanically coupleable with the syringe plunger coupling agent in the body, means arranged on the main body for releasing (7) the pipette tip (6) or syringe from the means for holding (5) with a manually operable actuating member (7.4) for actuating the means for releasing (7) without the displacing member (14) or the coupling agent is moved, a sensor (16) arranged on the base body (2) for detecting an actuation of the means for releasing (7) or a release of the pipette tip or syringe, a controllable drive (20) which is operatively connected to the displacement member (14) or the coupling means, - Input means (3) for controlling the steurbaren drive (20), - Electric control means (19) which are electrically connected to the steurbaren drive (20), the input means (3) and the sensor (16) and which are such that the controllable drive (20), when the sensor (16) detects an actuation of the means for releasing (7) or the disengagement of the pipette tip (16) or syringe, the displacement member (14) or the coupling means in shifted a basic position. Dosing device according to claim 1, wherein from the basic position of a displacement of the displacement member (14) or the coupling means for receiving liquid in a pipette tip (6) or syringe takes place. Dosing device according to claim 1 or 2, wherein the controllable drive (20) is an electric drive. Dosing device according to claim 3, wherein the controllable drive (20) is an electric drive motor. Dosing device according to at least one of claims 1 to 4, wherein the sensor (16) is a reed contact which can be actuated by displacement of a magnet (17) arranged on the means for releasing (7). Dosing device according to claim 5, wherein the magnet (17) arranged on the actuating member (7.4) and / or the reed contact (16) on a circuit board (18) in the base body (2) is arranged. Dosing device according to one of claims 1 to 6, wherein the means for holding (5) at least one clamping seat (5) for a pipette tip (6) and the means for releasing (7) with respect to the clamping seat displaceable Abwerfschieber (7.1) having one end for pressing a pipette tip (6) from the clamping seat (5), wherein the actuating member (7.4) is connected to the other end of the Abwerfschiebers (7.1). A dosing device according to any one of claims 1 to 7, wherein the control means (19) is arranged to displace the displacer (14) to a home position when the sensor (16) senses actuation of the release means (7). from which the extent of a further displacement of the displacer (14) is determined, and that they displace the displacer (14) to the home position upon reaching the home position. Dosing device according to claim 8, wherein the control means (19) are adapted to control a movement of the displacement member (14) in the home position and then in the home position when switching on the metering device (1). Dosing device according to at least one of claims 1 to 9, wherein a in the base body (2) arranged further sensor (36) which is electrically connected to the control means (19) detects the reaching of the basic and / or home position by the displacement member. Dosing device according to claim 10, wherein the further sensor (36) is a Hall sensor, which is actuated by a further magnet (34) connected to the displacement member, when the displacement member (14) reaches the base and / or home position. Method for dosing liquids by means of a dosing device (1) with means for holding (5) at least one pipette tip (6) and one Displacement device (12) with a displacement chamber (13) and a movable therein displacer (14) or means for holding a syringe with a syringe barrel and a syringe piston displaceable therein and couplable with the syringe plunger coupling means and one with the displacement member (14) or The activatable drive means (20) operatively connected to the coupling means and means for releasing (7) the pipette tip (6) or syringe from the means for holding (5) in the - An operation of the means for releasing (7) or the disengagement of the pipette tip or syringe is detected and - After an actuation of the means for releasing the displacing member (14) or the coupling means is displaced to a basic position. Method for dosing liquids according to claim 12, in which, starting from the basic position, the displacing member (14) or the coupling agent for receiving liquid is displaced into the pipette tip (6) or syringe. The method of claim 12 or 13, wherein the displacement member (14) or the coupling means is displaced when switching the metering device (1) in the basic position.

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