EP0873790A2 - Pipette - Google Patents

Abstract

A pipette arrangement for sucking and delivering a liq in a pipette (6), comprises a housing (1) and a receiving area (5) for the pipette. The arrangement has a cylinder (2) which contains a movable piston (3), and a suction line (4) leads from the receiving area to the cylinder.

Description

The invention relates to a pipetting device for aspirating and dispensing a liquid in a pipette with a housing and a holder for a pipette.

Such pipetting devices are already known. In DE-OS 20 58 836 is a pipetting device described, which has an elastic, hollow spherical suction ball, to which a suction nozzle, a ventilation nozzle and an emptying nozzle are attached are. When operating the known pipetting device, the pipette is inserted into the Recording inserted. The valve on the ventilation nozzle is compressed and at the same time the suction ball is compressed. Then the top the pipette in the liquid to be absorbed, the valve of the suction port pressed and the suction ball released. Having done the necessary in this way Amount of liquid that has been added to the pipette will be Suction port valve released. In order to dispense the liquid from the pipette again, the valve on the emptying nozzle is compressed.

From DE-PS 42 14 634 a similar pipetting device is known, in which the in the Liquid to be picked up by the expansion movement of a pipette first compressed rubber or similar suction ball Material is sucked in.

A disadvantage of the known pipetting devices is that the suction process the liquid in the pipette is difficult to control.

The object of the invention is in a pipetting device of the type specified at the beginning Way to make the filling process of the pipette more controllable.

This problem is solved by the characterizing features of the claim 1. The pipetting device has a cylinder in which a piston is longitudinally displaceable is led. A suction line leads from the pipette holder to the cylinder. The filling process of the pipette, that is, the suction of the liquid into the pipette in an equally controlled manner respectively.

Advantageous further developments are described in the subclaims.

It is advantageous to provide a suction valve in the suction line. The piston can then be operated several times, causing larger volumes of liquid to enter the pipette can be included. This can also result in higher accuracy can be reached when filling the pipette. A is preferably used as the suction valve Beak valve used. The suction valve or beak valve is preferably in Cylinder or provided in a bulge of the cylinder or cylinder housing.

The piston can be spring loaded. The piston is preferably spring-loaded in such a way that the suction movement of the piston is opposed to a spring force. It is advantageous to face away from the mouth of the suction line in the cylinder Provide a compression spring on the side of the piston. The compression spring preferably encloses a piston rod connected to the piston. If with a pipetting device with a spring-loaded piston, a suction valve or beak valve in the suction line the particular advantage is provided that after a suction movement the necessary return movement of the piston is supported by a spring force can be.

Another advantageous development is characterized in that the piston movement or the piston stroke is limited by a stop. In this case the pipetting device can also be used as a dosing device. The pipetting device is then suitable for sucking in defined liquid volumes. Advantageous is to provide a variable stop so that different predefined ones Volume can be sucked. The changeable stops can be provided at the end of a piston rod connected to the piston. The piston rod can be turned to adjust the respective stop and / or a stop fixed to the housing can be brought into different positions will.

According to a further advantageous development, there is a pressure valve on the cylinder provided, which is preferably designed as a beak valve. This is particularly so then advantageous if a suction valve is provided in the suction line. The pressure valve allows air to be removed from the cylinder during the Piston executes a pressure stroke between two suction strokes.

Another advantageous development is characterized in that the piston is connected to a piston rod protruding from the cylinder, on which a Actuating part is provided. The actuator can be used as a handle or finger grip be designed, in particular in the manner of a trigger on a pistol or a gun.

Another advantageous further development is characterized by a ventilation line, that leads from the cylinder to the outside and that on the mouth of the suction line in the side of the piston facing away from the cylinder opens into the cylinder. The mouth of the vent line is preferably located on that side of the piston on which the spring or compression spring or piston rod is also located. Due to the vent line leading into the open or into the environment, a Pressure equalization during the suction stroke on the side facing away from the mouth of the suction line Side of the piston.

According to a further advantageous development, one branches off from the suction line Free leading drain line, which can be closed by a first actuating element and is taxable. During the filling of the pipette the drain line is locked. If it is opened, a pressure equalization takes place through which the liquid is drained from the pipette.

The suction line can preferably be closed by a second actuating element and taxable.

Another advantageous development is characterized in that the suction line can be closed and opened at one point by the second actuating element is that on the side of the branch of the drain line facing away from the cylinder lies.

The first actuator and the second actuator are preferred provided on a valve operating lever. It is advantageous if the valve actuation lever rotatable in the housing of the pipetting device, i.e. fixed to the housing is stored. The valve actuation lever is preferably with an outward, ie Arm out of the housing for actuation or manual operation.

According to a further advantageous development, there is an ejection line, that branches off from the vent line and leads to the pipette holder.

The vent line can preferably be closed by a third actuating element and taxable.

The ejection line can preferably be closed by a fourth actuating element and taxable.

Another advantageous development is characterized in that the exhaust line can be closed at one point by the fourth actuating element and is controllable, that on the side of the branch remote from the cylinder Ejection line is located.

The third actuator and the fourth actuator are preferred provided on a valve operating lever. This is preferably the case around the same valve actuation lever on which the first actuation element is located and the second actuator are provided. The valve actuation lever is preferably rotatably mounted in the housing.

Fig. 1

ein Pipettiergerät in einer Schnittansicht von der Seite,

Fig. 2

eine schematische Ansicht des Pipettiergeräts während des Ansaugvorgangs,

Fig. 3

eine schematische Ansicht des Pipetterigeräts während des Flüssigkeits-Abgabevorgangs,

Fig. 4

eine schematische Ansicht des Pipettiergeräts während des Ausstoßvorgangs,

Fig. 5

eine weitere schematische Ansicht des Pipettiergeräts und

Fig. 6

eine abgewandelte Ausführungsform des Pipettiergeräts in einer Schnittansicht von der Seite.

Embodiments of the invention are explained below with reference to the accompanying drawings. In the drawing shows

Fig. 1

a pipetting device in a sectional view from the side,

Fig. 2

1 shows a schematic view of the pipetting device during the suction process,

Fig. 3

1 shows a schematic view of the pipetting device during the liquid dispensing process,

Fig. 4

1 shows a schematic view of the pipetting device during the ejection process,

Fig. 5

another schematic view of the pipetting device and

Fig. 6

a modified embodiment of the pipetting device in a sectional view from the side.

The pipetting device shown in FIG. 1 has a housing 1 in which a cylinder 2 is provided. A piston 3 is guided in a longitudinally displaceable manner in the cylinder 2. From a suction line 4 leads to the cylinder 2 to a pipette holder 5, in which one Pipette 6 releasably attached, namely inserted. The pipette holder 5 is in one Inserted housing attachment 7, which is screwed onto the housing 1.

The cylinder 2 consists of a cylinder part 8 and a head part 9. It is from Cylinder brackets 10, 11 bordered, which are connected to the housing 1.

The piston 3, which is longitudinally displaceable in the cylinder 2, is pot-shaped. The end part of the piston 3 is connected to a piston rod 12, on the latter the piston 3 facing away from a U-shaped extension 13 connects with an actuator 14 is connected. The actuating part 14 is a finger actuating part designed and has the form of a trigger of a pistol. It is in a slot 15 of the housing 1 and so spaced from a handle part 16 of the housing 1 arranged that one-handed operation is possible. To this For this purpose, the grip part 16 is gripped with the fist, with the fingers in the depressions of the grip part 16. The index finger can then the recessed grip 17 of the actuating part 14 pull in, i.e. move in the direction of arrow 18.

One end of a compression spring is supported on the rear of the end part of the piston 3 19 from which surrounds the piston rod 12 and which in the cylindrical shoulder of the cup-shaped piston 3 is used. The other end of the compression spring 19 is at the Cylinder bracket 11 supported. The piston rod 12 is in a sleeve shape Approach 20 guided in the cylinder holder 11. With the piston rod 12 is one with her aligned extension 21 connected in a shoulder 22 of the housing 1st is guided and at the end of a plurality of graduated paragraphs 23 are provided, the various stops for the piston rod 12 and thus the stroke movement of the Form piston 3.

A suction valve 24 designed as a beak valve is provided in the suction line 4. It is located in an extension 25 which is attached to the head part 9 of the cylinder 2 is molded. Furthermore, on cylinder 2 there is also a beak valve Pressure valve 26 is provided, which on another on the head part 9 of the cylinder 2 proposed approach is attached.

A vent line 27 leads from the cylinder 2 into the open. The vent line 27 opens into the cylinder 2 through the cylinder holder 11, namely the side of the piston facing away from the mouth of the suction line 4 into the cylinder 2 3rd

A drain line 28 leading from the outside branches off from the suction line 4. From the vent line 27 branches off an ejection line 29 which leads to the pipette holder 5 leads. The suction line 4 and the discharge line 29 are at 30 in one common line 31 leading to pipette holder 5.

In the housing 1, a valve actuating lever 32 is provided, which is about an axis 33 is rotatably mounted. On the valve operating lever 32 is a first operating element 34 provided, through which the drain line 28 can be closed and is controllable, a second actuating element 35 through which the suction line 4 can be closed and opened, a third actuating element 36, through which the vent line 27 can be closed and opened, and a fourth actuating element 37, through which the discharge line 29 can be closed and opened is. The valve operating lever 32 has a first lever arm 38 and one second lever arm 39, which enclose an angle of approximately 90 ° between them. The first actuating element 34 and the second actuating element 35 are located at the end of the first lever arm 38. The actuating elements 34, 35 close an angle of about 90 °, the first lever arm 38 substantially in Direction of the bisector runs. The third actuating element is in an analogous manner 36 and the fourth actuating element 37 at the end of the second lever arm 39 arranged. The actuating elements 36, 37 close an angle of about 90 ° with each other, the second lever arm essentially in the direction the bisector runs.

The suction line 4 can be closed at one point by the second actuating element 35 and controllable, that on the side facing away from the cylinder 2 of the branch the drain line 28 is. The discharge line 29 is through the fourth Actuating element 37 can be closed and opened at a point on the the side of the branch of the discharge line 29 facing away from the cylinder 2.

Ansaugen" (Fig. 2), Abgeben" (Fig. 3) und Ausstoßen" (Fig. 4) gezeigt.2, 3 and 4 are the switching positions of the actuators for the functions

Suction "(Fig. 2), Dispense "(Fig. 3) and Eject "(Fig. 4) shown.

2, the valve actuation lever 32 is in the position In this position, the drain line 28 is closed by the first actuation element 34. The suction line 4 is opened by the second actuation element 35. The vent line 27 is opened by the third actuation element 36. The discharge line 29 is closed by the fourth actuation element 37. When the piston 3 moves in the direction of the arrow 18, that is to say in the suction direction, the pressure valve 26 closes and the suction valve 24 is opened. The air is sucked into the cylinder 2 by the pipette 6 through the suction line 4. On the rear of the piston 3 The air can flow out through the vent line 27. The liquid 40 is sucked into the pipette 6 to form a liquid column 41.

The suction process can be repeated. When the actuator 14 is released is, the compression spring 19 pushes the piston 3 against the arrow direction 18 in the Starting position back. During this movement, the suction valve 24 and closes opens the pressure valve 26. The air in the cylinder 2 escapes through the open Pressure valve 26. Air flows onto the through the open ventilation line 27 Back of the piston 3. The liquid column 41 remains unchanged. Subsequently a new suction process can be carried out through which the liquid column 41 continues to rise.

In Fig. 3 the valve actuation lever 32 is in the position "It was brought into this position by moving the lever arm 42 against the force of the compression spring 43 fixed to the housing. The scale designation 0 "denotes the position Suction ", the scale name a "the position Submit "and the scale name b "the position The positions a and b are achieved by manual actuation of the lever arm 42, by means of which the valve actuation lever 32 is rotated about the lever pivot point or the axis of rotation 33.

In the position shown in Fig. 3 "The discharge line 28 has been opened by the first actuation element 34. The suction line 4 is still opened by the second actuation element 35. The vent line 27 is still opened by the third actuation element 36. The discharge line 29 is through the fourth actuation element 37. All actuating elements thus open the respective associated line, and air flows into the pipette through the emptying line 28 and the suction line 4. Since the emptying line 28 leads to the outside, a pressure equalization is created, through which the liquid from the pipette 6 downwards Air also flows into the pipette through the vent line 27 and the exhaust line 29. Since the vent line 27 also leads to the outside, ie is connected to the ambient pressure, the liquid is also removed from the pipette 6 as a result.

4, the valve actuation lever 32 is in the position The valve actuation lever 32 has thus been rotated further counterclockwise about the axis of rotation 33, so that the lever arm 42 has reached the scale designation b. In the position The discharge line 28 is still opened by the first actuation element 34. The suction line 4 has been closed by the second actuation element 35. The vent line 27 has been closed by the third actuation element 36. The discharge line 29 is opened by the fourth actuation element 37 remained.

By actuating the piston 3 in the direction of arrow 18, the suction valve 24 opened and the pressure valve 26 closed. Ambient air flows through the Drain line 28 and the suction line 4 in the cylinder 2. Furthermore, the Piston 3 on its back air through the vent line 27 and the exhaust line 29 into the pipette 6. As a result, the remaining on the pipette tip, drop-shaped liquid residue 44 can be reliably blown out. Furthermore, thereby accelerating the dispensing process of the liquid from the pipette 6.

Fig. 5 shows schematically the switching positions of the valve actuating lever 32 and the actuating elements located thereon in their interaction with the various lines. In Fig. 5a the valve actuation lever 32 is in the position Suction ", in Fig. 5b in the position Dispense "and in Fig. 5c in the position Blow out ".

Fig. 6 shows a modified embodiment, which is essentially that corresponds to Fig. 1. In contrast to the embodiment according to FIG. 1, the 6, the pipette holder 5 'is not below the handle part 16 arranged, but at the lower end of a bend 45 of the housing 1, the connects to the head part 9 of the cylinder 2 and from there to the front and down runs. Accordingly, the common line 31 is around the cylinder 2 led to the pipette holder 5 '.

Claims (18)

Pipetting device for aspirating and dispensing a liquid in a pipette (6) with a housing (1) and a receptacle (5) for a pipette (6),
marked by
a cylinder (2), in which a piston (3) is guided in a longitudinally displaceable manner, and a suction line (4) from the pipette holder (5) to the cylinder (2). Pipetting device according to claim 1, characterized in that in the suction line (4) a suction valve (24), preferably a beak valve, is provided. Pipetting device according to claim 1 or 2, characterized in that the piston (3) is spring-loaded (19). Pipetting device according to one of the preceding claims, characterized in that that the piston movement by a stop, preferably a changeable stop (23) is limited. Pipetting device according to one of the preceding claims, characterized in that that on the cylinder (2) a pressure valve (26), preferably a Beak valve is provided. Pipetting device according to one of the preceding claims, characterized in that that the piston (3) with a piston rod protruding from the cylinder (12) is connected, on which an actuating part (14) is provided. Pipetting device according to one of the preceding claims, characterized through a ventilation line (27) leading from the cylinder (2) to the outside and those facing away from the mouth of the suction line (4) into the cylinder (2) Side of the piston (3) opens into the cylinder (2). Pipetting device according to one of the preceding claims, characterized in that that of the suction line (4) leading to the outside drain line (28) branches off, which can be closed by a first actuating element (34) and is taxable. Pipetting device according to one of the preceding claims, characterized in that that the suction line (4) by a second actuating element (35) lockable and taxable. Pipetting device according to claim 8 and 9, characterized in that the suction line (4) can be closed at one point by the second actuating element (35) and can be opened, that on the cylinder (2) facing away Side of the branch of the drain line (28). Pipetting device according to one of claims 8 to 10, characterized in that the first actuator (34) and the second actuator (35) are provided on a valve actuation lever (32). Pipetting device according to claim 11, characterized in that the valve actuation lever (32) is rotatably mounted in the housing (1). Pipetting device according to one of claims 7 to 12, characterized by a Ejection line (29) that branches off from the ventilation line (27) and to the Pipette holder (5) leads. Pipetting device according to one of claims 7 to 13, characterized in that that the ventilation line (27) can be closed by a third actuating element (36) and is taxable. Pipetting device according to claim 13 or 14, characterized in that the Ejection line (29) can be closed by a fourth actuating element (37) and is taxable. Pipetting device according to claim 14 and 15, characterized in that the Ejection line (29) through the fourth actuating element (37) at one point can be closed and opened, on the side facing away from the cylinder (2) Side of the branch of the discharge line (29). Pipetting device according to one of claims 14 to 16, characterized in that that the third actuator (36) and the fourth actuator (37) are provided on a valve actuating lever (32), preferably on the Valve actuating lever (32) with the first actuating element (34) and the second actuator (35). Pipetting device according to claim 17, characterized in that the valve actuation lever (32) is rotatably mounted in the housing (1).

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