EP2810704A1 - Adapter for a motor-powered agitator, agitator and agitator block for mixing liquid samples in micro- and millilitre reaction vessels - Google Patents

Abstract

An adapter for a motor-driven stirrer and stirrer and stirrer block for mixing liquid samples in micro and milliliter reaction vessels is proposed. The adapter (1) is equipped with a stirrer coupling (4), via which the adapter (1) with the stirrer (8) can be connected and driven to rotate, with a Rührstab recording (2) into which one end of a stirring rod (3) is insertable in the axial direction, wherein the Rührstabaufnahme (2) the stirring rod (3) substantially coaxially aligned with the axis of rotation of the adapter (1), wherein the stirring rod (3) can be set into a tumbling motion by the rotating adapter (1), so that the stirring rod (3) simultaneously performs a first rotational movement about its own axis and a second rotational movement about a non-constant rotational axis.

Description

The invention is based on an adapter for a motor-driven stirrer for mixing liquid samples in micro and milliliter reaction vessels.

State of the art

Such adapters are already known. They are mainly used in conjunction with laboratory stirrers, which are used for mixing liquids, in particular for solids-containing liquids and multiphase mixtures, as they are needed in the isolation of nucleic acids and proteins. Frequently, such analyzes are carried out in parallel in test series with a large number of samples in respective reaction vessels. The stir bars used in conjunction with these adapters are therefore usually simple cylindrical disposable items, so that the cost of their production can be minimized.

The adapters are usually equipped with a stirrer coupling, via which the adapter can be connected to the stirrer and driven to rotate. In the simplest case, such a stirrer coupling consists of a region of the adapter to which the drive shaft of the stirrer motor acts directly or indirectly. In addition, the adapters have a stirring rod receptacle into which one end of a stirring rod can be introduced in the axial direction, wherein the stirring rod receptacle aligns the stirring rod substantially coaxially with the axis of rotation of the adapter. The power of a stirrer motor is transmitted to the stirring rod in the known adapters by the stirring rod is releasably clamped in a Einklemmeinrichtung or a chuck of the adapter. The engaging in the adapter stir bar in this case performs a simple rotational movement about its longitudinal axis. The sample contained in a reaction vessel is caused to flow by this rotational movement of the stirring rod. Frequently, however, the flow thus generated is not sufficient to mix the sample batches contained in the reaction vessels - in particular with a short stirring time - to a satisfactory extent.

To increase the efficiency of the stirring process, it is known to equip stirring rods with extensions such as stirring blades, which are intended to improve the mixing action of the stirring rod by influencing the flow. However, such a modification of the stirring bars is only economical if the stirring bars find repeated use.

The object of the invention is therefore to provide an adapter for a stirrer, which ensures efficient mixing, regardless of the stirring bar used.

The invention and its advantages

The object is achieved by an adapter according to claim 1, wherein the stirring rod is displaceable by the rotating adapter in a tumbling motion, so that the stirring rod simultaneously performs a first rotational movement about its own axis and a second rotational movement about a non-constant axis of rotation. To such a double axis rotation, a stirring rod inserted loosely into an adapter is displaceable by the rotating adapter. The stir bar is not fixed in the adapter holder. The transmission of the torque of the adapter to the stirring rod is effected by frictional forces that take the stirring rod in contact with the Rührstab recording. Due to the degrees of freedom available to the stir bar inserted in the stir bar receptacle, this not only performs a simple rotational movement about its longitudinal axis, but is capable of rotating about a non-constant axis. In this gyroscopic movement, the deflection of the axis of rotation of the stirring rod with respect to the axis of rotation of the adapter during the stirring process is variable. A stirrer rod driven by the adapter, due to its free placement in the stir bar receptacle, can perform a more spacious rotational movement than a conventionally powered stir bar, which performs a simple rotational movement about its longitudinal axis. In this case, the stirring rod experiences an angular momentum as soon as its deflection is correspondingly large and it touches the rotating adapter receptacle. As a result, torques are repeatedly transmitted from the stirrer holder to the stirring rod. The movement of the stirring rod caused by the adapter during rotation causes turbulence in the medium to be mixed. The rotating adapter thus induces additional turbulence in the flow via a stirring rod, thereby enabling more effective mixing.

Another advantage of the adapter is that it can be used in conjunction with reaction mixtures containing magnetic particles, as they are often used in the RNA, DNA and protein analyzes described above. The absence of magnetic forces avoids disruptive effects that could falsify a test result.

According to an advantageous embodiment of the invention, the Rührstab recording is free of a clamping or tensioning device. It is also advantageous if the adapter is free of further mechanical devices which engage radially and / or axially on a stirring rod introduced into the stirring rod receptacle and, for example, could exert undesired frictional forces on the stirring rod in the manner of a bearing. In addition, the first rotational movement due to a lack of thrust bearing and the associated friction forces have the same direction as the rotational movement of the adapter. Another advantage of the free of mechanical fasteners adapter is that the mediated via the adapter unit of stirrer and stirring rod at any time easy to solve. It requires no additional time-consuming handles, as they are necessary for the release or production of mechanical positive or non-positive connections. In addition, the adapter, which can be connected loosely with a stir bar, does not contain any possibly mobile ejection or holding devices which are exposed to wear or contamination and which require additional care or maintenance.

According to a further advantageous embodiment of the invention, the second rotational movement is a rotational movement of the stirring rod axis on the lateral surface of a double cone. Such rotational movement can be induced by the rotating adapter in the stir bar located in the stir bar. The two cones that form the double cones face each other with their tips. During this rotational movement, the stirring rod with its two stirring rod ends each describes a circular movement, wherein the ends of the Rührstabs have a greater deflection with respect to the axis of rotation of the adapter, as the deflection of the sections between the two ends. However, other forms of rotational movements are possible, such as a rotational movement on the lateral surface of a cone. The shape of the rotational movement depends, among other things, on the geometries of the adapter receptacle and the dimensions of the reaction vessel, which is used in conjunction with the adapter. The deflections of the stirring rod in the reaction vessel can thus be influenced by the choice of an adapter and the associated ratio of diameter or cross section of the stirring rod recording of the adapter and diameter or cross section of the reaction vessel. As a result, stirring movements of the stirring rod with the greatest possible deflection of the stirring rod in a reaction vessel can be achieved. It is also possible that various forms of rotational movements occur in a stirring process.

According to a further advantageous embodiment of the invention, the adapter or at least the Rührstab recording of the adapter made of plastic. This is advantageous because the adapter or the stirring rod recording are then particularly easy to clean. In addition, the production of adapter or Rührstabaufnahme is easy and inexpensive. However, other materials are conceivable. Care must be taken only that the stirring rod can be taken by appropriate frictional forces of the rotating adapter.

According to a further advantageous embodiment of the invention, at least the stirring rod receptacle is integrally formed. A one-piece design allows for easy cleaning. It is particularly advantageous in this case if parts which face the reaction vessel, for example the inner wall of the stirring-rod receptacle, are closed and continuous.

According to a further advantageous embodiment of the invention, the stirring rod receptacle is formed as a hollow cylinder. In particular, circular cylindrical stirring rod receptacles in the manner of a blind hole are preferred because of their symmetry. In the simplest case, the stirring rod receptacle is formed by a recess which is bounded by a type of sleeve or a cup, which may or may be the adapter. As a result, a cost-effective production is possible.

According to a further advantageous embodiment of the invention, the Rührstab recording on an insertion funnel. The insertion funnel may be located in front of the stirring rod receptacle, relative to the insertion direction of the stirring rod. The insertion funnel can taper conically up to the stirring rod holder. It is possible that the insertion funnel is distinctly offset from the stirring rod receptacle or flowing into it. Through the insertion funnel a simple and directed introduction of the stirring rod is made possible in the stirring rod adapter.

The uses of the adapter according to the invention for laboratory applications are many. Thus, a corresponding adapter can be effectively used in conjunction with narrow, high reaction vessels, but also with wider beakers. Although stirring rods made of plastic are often used for the analyzes described above, but the adapter is also suitable in conjunction with stirring rods made of other materials such as wood or metal. Here, the shape of the cross section of the stirring bar is irrelevant. For example, stirring rods having a circular, ellipsoidal, rectangular or polygonal cross section may be used. All stir bars where the circumference of the stir bar's envelope is smaller than the inside diameter of the stir bar take up provide excellent mixing results. Advantageously, the internal diameter of the stirring rod holder is at least 10% larger than the circumference of the envelope of the stirring rod; Preferably, the inner diameter is at least 30% larger, more preferably at least 50% larger than the circumference of Enveloping the stir bar. In particular, stirring rods in which the circumference of the envelope of the stirring rod is about 2 mm, have a favorable size ratio to a stirring rod holder having an inner diameter of about 3 mm. In addition, the adapter according to the invention can be used with a wide variety of stirrers.

Another object of the invention is therefore also a stirrer for mixing liquid samples in micro-milliliter reaction vessels containing an adapter according to the invention. The stirrer is equipped with a stirrer housing, with a motor in the stirrer housing for driving the adapter and suitable means for indirectly or directly transmitting the driving force of the motor to the adapter. In this case, the motor of the stirrer drive a shaft or spindle, which may be integrally, non-positively and / or positively connected to the stirrer coupling of the adapter. However, there are also other ways of connecting conceivable, such as cohesive connections in which the shaft can be glued into the adapter. It is particularly advantageous if the connection between the stirrer and the stirrer coupling of the adapter is designed to be detachable. This makes it possible that adapters with different stirring rod recordings, which are particularly well adapted to the dimensions of a particular type of stirring rod, can be used in conjunction with the same stirrer. These may in particular be adapters with different inner diameters in the stirrer recording.

The stirrer is aligned in use so that the stir bar receptacle is freely accessible and the axis of rotation of the adapter is substantially coaxial with the stirring bar located in the reaction vessel. The reaction vessel can now be brought by a user to the Rührstab recording so that the stirring rod located in the reaction vessel can be introduced into the Rührstab recording and also rotated. The introduction of the stirring bar can already be made rotating adapter. However, the rotation of the adapter can also be started only after the introduction of the stirring rod. This allows a versatile use of the stirrer. The stirrer can thus replace mixing devices such as shaking or time-consuming and laborious manual mixing by repeatedly drawing up the reaction mixture with a pipette. It is advantageous that a single stirrer can be used to mix many samples. In addition, the stirring bars can each remain in the individual reaction vessels in the mixing steps to be carried out. This has the additional advantage that a stir bar can be maintained for multi-step processing of a sample in a reaction vessel, thus producing less waste.

According to an advantageous embodiment of the stirrer, the stirrer housing or a part of the stirrer housing with a stand or a tripod is detachably connected or integrally formed. This makes it possible to position the stirring rod of the adapter on a work surface, a table or a laboratory bench so that it is freely accessible. In addition, this allows multiple users to fall back on the stirrer in a simple manner.

According to a further advantageous embodiment of the stirrer, the housing of the stirrer is designed as a handle. This allows a particularly simple and flexible handling of the stirrer. A user can mix with the stirrer successively several reaction mixtures, wherein he inverts the adapter loosely over a stirring rod located in a reaction vessel. The reaction vessels can be individually selected and edited here. The handle of the stirrer may be ergonomically shaped for improved handling. This is particularly desirable when the largest possible amount of samples to be processed.

Another subject of the invention is a stirrer block containing at least two adapters according to the invention, with a stirrer block housing, with at least one motor in the stirrer block housing for driving the adapter and suitable means for direct or indirect transmission of the driving force of the motor to the adapter. Such an arrangement is advantageous when analyzes with many samples in their respective reaction vessels are to be carried out synchronously. In particular, nucleic acid and protein analyzes generally involve series of tests with a variety of samples and many steps. The steps include, for example, lysis of the cells to be tested, binding of the target molecules to a particular sorbent, and repeated washing and elution steps to purify and recover the target molecules. With the help of the stirrer block, the simultaneous rotation of a large number of stirrers is possible. This enables synchronous and effective processing of many samples. For this purpose, only a corresponding number of adapters must be rotatably arranged in the stirring block. Depending on the design, several adapters can be driven together by one motor or individually. This means that an adapter in the stirrer block can be driven by an individual motor. However, it is also possible to drive several adapters using a motor.

Further advantages and advantageous embodiments of the invention will become apparent from the following description, the drawings and the claims.

drawing

Figur 1

eine Ausführungsform des Adapters, wobei Figur 1a eine perspektivische Darstellung des Adapters mit freigelegter Rührstab-Aufnahme zeigt, Figur 1b einen Längsschnitt durch eine perspektivische Darstellung des Adapters aus Figur 1a; und Figur 1c einen Längsschnitt durch eine perspektivische Darstellung des Adapters aus Figur 1a mit einem skizzierten Rührstab; Figur 1d zeigt eine Prinzipskizze des Adapters aus Figur 1a, die das Verhältnis des Innendurchmessers der Rührstab-Aufnahme zum Umfang der Umhüllenden eines Rührstabs darstellt;

Figur 2

eine Ausführungsform eines Rührers, dessen Gehäuse zu einem Handgriff ausgeformt ist, wobei Figur 2a eine perspektivischer Darstellung des Rührers zeigt und Figur 2b den Rührer, wie er bei der Benutzung gehandhabt werden kann;

Figur 3

eine Prinzipskizze eines Arbeitszyklus mit dem Rührer gemäß Figur 2;

Figur 4

zwei Ausführungsbeispiele für ein Gehäuse eines Rührerblocks in perspektivischer Darstellung, wobei Figur 4a ein Gehäuse für eine lineare Anordnung von Rührern zeigt und 4b ein Gehäuse für mehrere Reihen linearer Anordnungen von Rührern.

Reference to the drawing, an embodiment of the adapter, the stirrer and a housing for a stirring block are explained in detail. Show it

FIG. 1

an embodiment of the adapter, wherein FIG. 1a shows a perspective view of the adapter with exposed stir bar recording, FIG. 1b a longitudinal section through a perspective view of the adapter FIG. 1a; and Figure 1c a longitudinal section through a perspective view of the adapter FIG. 1a with a sketched stir bar; Figure 1d shows a schematic diagram of the adapter FIG. 1a representing the ratio of the inside diameter of the stir bar receptacle to the circumference of the envelope of a stir bar;

FIG. 2

an embodiment of a stirrer whose housing is formed into a handle, wherein FIG. 2a a perspective view of the stirrer shows and FIG. 2b the stirrer as it can be handled in use;

FIG. 3

a schematic diagram of a working cycle with the stirrer according to FIG. 2 ;

FIG. 4

two embodiments of a housing of a stirrer block in a perspective view, wherein FIG. 4a Figure 4 shows a housing for a linear array of stirrers, and Figure 4b shows a housing for multiple rows of linear arrays of stirrers.

The FIG. 1a shows an embodiment of the adapter 1 with a Rührstab recording 2. The adapter 1 is in FIG. 1a shown partially cut longitudinally, wherein the sectional plane is dotted by the adapter 1. The stirring rod holder 2 is exposed for the most part and also cut longitudinally. In addition, in FIG. 1a shown is a stirring rod 3, of which only the upper portion is shown for simplicity. The arrow in FIG. 1a indicates the insertion direction of the stirring rod 3 in the stirring rod receptacle 2 of the adapter 1. Also in FIG. 1a to recognize the funnel-shaped configuration of the stirrer holder 2. This facilitates the insertion of the Stirring rod 3 in the stirrer receptacle 2. A stirrer coupling 4, with which the adapter 1 can be connected to a stirrer, is inter alia in FIG. 1b shown.

FIG. 1b shows a longitudinal section through a perspective view of the adapter 1 FIG. 1a , In FIG. 1b the adapter 1 is shown with a stirring rod 3 introduced into the stirring rod receptacle 2. Through the three unfilled arrows in FIG. 1b the relationship between the direction of rotation of the adapter 1 and the direction of rotation of the stirring rod 3 is clarified, it being understood that adapter 1 and stirring rod 3 rotate in the same direction. In addition, the two unfilled arrows in the area of the stirring bar 3 should clarify the double axis rotation of the stirring bar 3 when the adapter 1 is rotating. The filled arrow in FIG. 1b indicates the direction of the centrifugal force acting on the stirring rod 3 during rotation of the adapter 1.

Figure 1c shows a longitudinal section through a perspective view of the adapter 1 FIG. 1a with a sketched stirring rod 3 to illustrate a possible rotational movement of the stirring rod 3 in the rotating adapter 1. The rotation of the adapter 1 is not shown. In the sketched rotational movement is a rotational movement on the lateral surface of a cone that can perform the introduced into the adapter 1 stirring rod 3 upon rotation of the adapter 1 with its Rührstabsachse.

Figure 1d shows a schematic diagram of the adapter FIG. 1a representing the ratio of the inner diameter 6 of the stirring rod holder 2 to the circumference of the envelope 7 of a stirring rod 3. The shape of the Rührstabquerschnitts 5 plays no special role. For example, stir bars with circular 5a, ellipsoidal 5b, rectangular 5c or polygonal 5d cross section may be used.

The FIG. 2 shows an embodiment of a stirrer whose housing is formed into a handle. This shows FIG. 2a a perspective Representation of the stirrer 8 with a housing 9 and an adapter 1. The configured as a handle housing is loose when using the stirrer 8 in the hand of a user, as in FIG. 2b shown. At the end facing away from the adapter 1 switching buttons 10 a, b, c are arranged to start and end the rotation of the adapter and for different working modes. They can be conveniently reached and operated with the thumb of the hand embracing the hand as out FIG. 2b seen. The housing 9 of the stirrer 8 runs out at the end of the stirrer 8 facing away from the adapter 1 to form a hook. With this hook, the stirrer 8 is stored on the hand during use by a user, with which the stirrer 8 is embraced. As a result, fatigue of the hand guiding the stirrer 8 is delayed, even when processing a plurality of samples. In addition, the stirrer 8 can be hung to save space after completion of the work, for example, to a present in most laboratories pipette stand (not shown). The stirrer 8 is wireless and is a in the FIG. 2 not visible, multiple rechargeable battery powered, which is located inside the housing 9. In order to allow replacement of the battery, the housing 9 consists of two parts, which are detachably connected to each other.

FIG. 3 shows a schematic diagram of a duty cycle with the stirrer according to FIG. 2 , First, the stirrer 8 is moved with the adapter 1 by a user to a reaction vessel 11 ( FIG. 3a ) and the stir bar 3 into the stir bar receptacle 2, which are in FIG. 1 is introduced ( FIG. 3b ). The stir bar 3 loosely engages the stir bar receptacle 2. When the adapter 1 rotates after operation of the start button 10c, the stirring rod 3 is also rotated by the action of rubbing and centrifugal forces. One possible form of rotational movement of the stirring bar is in Figure 1c shown. The stirring rod 3 may initially perform a relatively upright rotational movement due to a transmitted from the adapter 1 to the stirring rod 3 and the adjusting gyroscopic effect, wherein the stirring rod 3 otherwise free in the adapter receptacle. 2 emotional. Due to the decreasing angular momentum, the stirring rod 3 rotates under increasing deflections wanking and finally touches again the adapter receptacle, where he again receives a pulse. The tumbling movements performed by the stirring bar 3 are in Figure 3c not shown. After completion of the mixing operation, the stirrer 8 is simply lifted off the stirring bar 3 and reaction vessel 11. The stirring rod 3 in this case remains in the reaction vessel 11 (FIG. 3d figure ).

FIG. 4 shows two embodiments of a housing of a stirrer block 12 in a perspective view, wherein FIG. 4a a housing 12 for a linear arrangement of stirrers and 4b shows a housing for a plurality of rows of linear arrays of stirrers.

In FIG. 4a a housing 12 is shown, which consists of two main components. First, the housing 12 includes a base 13 which is loaded with a holding device 14 for reaction vessels 11. The holding device 14 is not firmly connected to the base 13 and can be easily lifted and replaced at any time from the receptacle 15 in the base. About height adjustable guides 16, the base 13 is connected to a block unit 17, in which there is a linear arrangement of stirrers. The stirrers of the arrangement are in the FIG. 4a not visible. However, they are oriented such that each reaction vessel 11 located in the holding device 14 is assigned a stirrer with adapter 1. By raising and lowering the blocking unit 17, the stirrers and the adapters 1 can be loosely brought into contact with the stirring bars 3 of the reaction vessels 11 and also removed therefrom.

In FIG. 4b a housing of a stirrer block 12 is shown, which in principle shows the same structure as the housing 12 of the FIG. 4a , In contrast to the housing 12 off FIG. 4a has the case of the FIG. 4b a widened block unit 17 in which a plurality of rows of linear arrays of stirrers are included. The stirrers are in the FIG. 4b Not visible because they are covered by the housing 12 of the stirrer block. To facilitate the loading and unloading of the receptacle 14 for holding devices 15, the receptacle 15 is equipped with a kind of loading ramp, which is formed by the fact that a part of the receptacle 15 delimiting wall of the base 13 has been omitted.

All features of the invention may be essential to the invention both individually and in any combination with each other.

LIST OF REFERENCE NUMBERS

1

adapter

2

Stir bar shooting

3

whisk

4

Stirrer clutch

5

Rührstabquerschnitt

6

Inner diameter of the stirring rod holder

7

Scope of Stirring Bar Envelope

8th

Handrührer

9

Rührergehäuse

10

control buttons

11

reaction vessel

12

Rührerblockgehäuse

13

base

14

Holding device for reaction vessels

15

Holder for holding device

16

guide

17

block unit

Claims (11)

Motor-driven stirrer adapter (1) for mixing liquid samples in micro and milliliter reaction vessels,
with a stirrer coupling (4), via which the adapter (1) can be connected to the stirrer (8) and driven to rotate,
with a stirring rod receptacle (2) into which one end of a stirring rod (3) can be inserted in the axial direction, the stirring rod receptacle (2) aligning the stirring rod (3) substantially coaxially with the axis of rotation of the adapter (1),
characterized in that the stirring rod (3) is displaceable by the rotating adapter (1) in a tumbling motion, so that the stirring rod (3) simultaneously performs a first rotational movement about its own axis and a second rotational movement about a non-constant axis of rotation. Adapter (1) according to claim 1, characterized in that the stirring rod receptacle (2) is free of a clamping or tensioning device. Adapter (1) according to claim 1 or 2, characterized in that the second rotational movement is a rotational movement of the stirring rod axis on the lateral surface of a double cone. Adapter (1) according to one of the preceding claims, characterized in that the adapter (1) or at least the RührstabAufnahme (2) of the adapter (1) consists of plastic. Adapter (1) according to one of the preceding claims, characterized in that at least the stirring rod receptacle (2) is integrally formed. Adapter (1) according to one of the preceding claims, characterized in that the stirring rod receptacle (2) is formed as a hollow cylinder. Adapter (1) according to one of the preceding claims, characterized in that the stirring rod receptacle (2) has an insertion funnel. Stirrer for mixing liquid samples in micro and milliliter reaction vessels, comprising an adapter (1) according to one of claims 1 to 7,
with a stirrer housing,
with a motor in the stirrer housing for driving the adapter (1) and with suitable means for direct or indirect transmission of the driving force of the motor to the adapter (1). Stirrer according to claim 8, characterized in that the stirrer housing (9) or a part of the stirrer housing with a stand or a tripod is detachably connected or integrally formed. Stirrer according to claim 8 or 9, characterized in that the housing (9) of the stirrer (8) is designed as a handle. Stirrer block for the synchronous mixing of liquid samples in micro and milliliter reaction vessels, comprising at least two adapters (1) according to one of claims 1 to 7,
with a stirrer block housing (12),
with at least one motor in the housing for driving the adapters (1) and suitable means for direct or indirect transmission of the driving force of the motor to the adapters (1).

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