Device and method for agitating a container for automatic dispenser of culture media

Abstract

A device for agitating a container for a culture media dispenser is proposed, comprising: means for moving the container (10, 12) along a translation axis (T) between a pouring station and an agitation station, means for gripping the container (20) capable of taking at least two operating states, said gripping means being configured to cooperate with the moving means such that the gripping of the container is activated as the container is moved from the pouring station to the agitation station and is deactivated as the container is moved from the agitation station to the pouring station, and means for controlling the agitation of the container activated when the container is gripped.

Description

technical field

[0001] The invention relates to the field of culture media distribution systems. More specifically, the invention concerns an agitation technique for an automatic culture media dispenser. Previous art

[0002] Alliance Bio Expertise has developed a Petri dish culture medium dispenser particularly well-suited for use in microbiology laboratories. This dispenser is a programmable logic controller (PLC) configured to automatically fill Petri dishes with a given culture medium and stack the filled dishes in a loading carousel.

[0003] Once the culture medium has been poured into the dish and before being loaded into a carousel, each Petri dish undergoes a shaking operation to homogenize the poured medium with a seeded sample.

[0004] However, to meet a number of requirements, this operation must be sufficiently precise and efficient. Indeed, a prolonged operation can lead to contamination from external elements and also negatively impact the distributor's output. Furthermore, homogenization must be as optimal as possible to meet the required quality standards.

[0005] However, this stirring operation is traditionally carried out by hand, which is not optimal.

[0006] Furthermore, the use of a known gripping system such as a mechanical clamp or tackante adhesive paste, for example, remains a rather ineffective solution in practice.

[0007] Therefore, there is a real need to provide an automated and efficient stirring solution for automatic culture media dispensers.

[0008] US document 2017 / 227562 A1 discloses a device according to the preamble of claim 1 and a method according to the preamble of claim 6. Summary of the invention

[0009] In a particular embodiment of the invention, a device for agitating a container for a culture media dispenser is proposed, said container being intended to hold a culture medium to be agitated. Such a device according to the invention comprises: mechanical means for moving said container along a translation axis between a pouring station and an agitation station; means for gripping said container that can take at least two operating states: a first state, called inactive, in which no gripping of said container is carried out, and a second state, called active, in which said gripping means ensure the gripping of the container, said gripping means being configured to cooperate with the movement means in such a way that the gripping of the container is activated as said container is moved from the pouring station to the agitation station and is deactivated as the container is moved from the agitation station to the pouring station; means for controlling the agitation of said container, called gripped container, activated when said gripping means are in the second state.

[0010] Thus, the invention enables, through mechanical drive of the container, automated and efficient gripping of the container for agitation. To achieve this, the invention relies on an ingenious approach consisting of integrating mechanical drive means with container gripping means, thereby leveraging the container's movement to fully automatically activate the gripping and agitation. This clever configuration thus offers a novel and inventive solution for automatic agitation of culture media dispensers.

[0011] According to the invention, the control means comprise means for rotating mechanical movement means around the translation axis. These gripping means comprise at least one pneumatic suction cup having a central receiving axis for the container. The suction cup and the mechanical movement means are arranged so that the central receiving axis and the translation axis do not coincide. In this way, when the rotation means are activated, the suction cup undergoes at least one rotational movement around the translation axis, resulting in at least one elliptical shaking motion of the container.

[0012] The presence of at least one pneumatic suction cup offers a more practical and precise gripping alternative to known solutions such as gripping clamps or tackable adhesive paste. Furthermore, moving the container not only creates the suction effect but also optimizes the dispensing process. Since the container is agitated outside the dispensing station, this allows for simultaneous agitation and dispensing from another container within the dispenser.

[0013] According to a particular feature of the invention, the device comprises an offset plate for at least one suction cup, said plate having a lower face fixed rigidly to said mechanical movement means and an upper face fixed to said at least one suction cup. This allows the central receiving axis of the suction cup to be offset relative to the translation axis T so that the container is set in an elliptical rotational motion.

[0014] Such an approach offers an interesting alternative to conventional agitation solutions.

[0015] According to another particular aspect of the invention, the control means are configured to control the rotation means so as to allow at least one iteration of the following sequence: first rotational movement around the axis of translation; cessation of the first rotational movement; and second rotational movement around the axis of translation in a direction of rotation opposite to the first movement, taking into account a predetermined duration from the cessation.

[0016] This sequence allows for particularly effective agitation of the culture medium. The predetermined duration is calculated so that the liquid does not have time to return to a state of rest.

[0017] According to a particular implementation of the invention: The mechanical means of movement include a helical screw, a cylindrical tube cooperating with said screw to allow movement of the container along the axis of translation, and a motor for rotating said helical screw; the gripping means further include a vacuum assembly cooperating with said at least one suction cup to actuate said at least one suction cup, said assembly being formed of a fixed piston and said cylindrical tube, which cylindrical tube is movable in translation relative to the piston.

[0018] In another particular embodiment of the invention, a culture media dispenser is proposed comprising the aforementioned stirring device (in any one of its various embodiments).

[0019] In another particular embodiment of the invention, a method is proposed for agitating a container for a culture media dispenser, said container containing a culture medium to be agitated. Such a method comprises the following steps: gripping of said container by mechanical movement of said container from a pouring station of the culture medium, in which no gripping of said container is carried out, to a stirring station of said container, in which said container is gripped; stirring of said gripped container; degripping of said container by mechanical movement of said container from the stirring station to the pouring station.

[0020] According to the invention, the stirring step comprises at least one iteration of the following steps: first rotation of the mechanical means, to cause a first elliptical agitation movement of said container; cessation of the first rotation; second rotation of the mechanical means in a direction of rotation opposite to the first rotation, to cause a second elliptical agitation movement of said container in a direction opposite to the first movement, carried out before the elapse of a predetermined time from the cessation of the first rotation.

[0021] This sequence allows for particularly effective agitation of the culture medium. The predetermined duration is calculated so that the liquid does not have time to return to a state of rest.

[0022] In one particular implementation, this sequence is iterated several times. Such an approach further improves the efficiency of agitation, for example, in the case of viscous or poorly miscible culture media.

[0023] In another embodiment of the invention, a computer program product according to claim 8 is proposed which includes program code instructions for implementing the aforementioned method (in any of its various embodiments), when said program is executed on a computer.

[0024] In another embodiment of the invention, a computer-readable and non-transient storage medium is proposed, storing a computer program comprising a set of instructions executable by a computer to implement the aforementioned process (in any one of its various embodiments). Figures

[0025] Other features and advantages of the invention will become clearer upon reading the following description of a preferred embodiment, given by way of simple illustrative and non-limiting example, and the accompanying drawings, among which: there Figure 1 schematically represents an automatic culture media dispenser equipped with a stirring device according to a particular embodiment of the invention; Figure 2 is a perspective view of the stirring device according to a particular embodiment of the invention in a casting station; the Figure 3 is a truncated view of the view illustrated in the figure 2 detailing the means of gripping and moving the device; the Figure 4 is a perspective view of the device in the agitation position; the Figure 5 is a truncated view of the view illustrated in the figure 4 illustrating the stirring step according to the invention; the Figure 6is a side view of the device in the shaking position; the Figure 7 illustrates a particular embodiment of the stirring process according to the invention; the Figure 8 illustrates in a simplified manner a control module implementing the process according to a particular embodiment of the invention; the Figure 9 illustrates, in top and side views, the principle of eccentricity of the gripping suction cup according to the invention. Detailed description of the invention

[0026] In the figures in this document, identical elements are designated by the same numerical reference.

[0027] The general principle of the invention is based on automating the stirring operation of Petri dishes within the framework of an automated distribution of culture media into Petri dishes. This automation allows for efficient stirring of the culture medium poured into the Petri dishes and optimizes the processing rate of the dishes by the dispenser.

[0028] The remainder of this document focuses more specifically on describing the invention in the context of an automated dispensing system for culture media in Petri dishes, adapted for use in a microbiology laboratory. The invention is, of course, not limited to this particular field of application, but is of interest for any type of culture container (or vessel) requiring agitation of the culture medium.

[0029] There figure 1This schematically presents the principle of an SD automatic dispenser for culture media in Petri dishes. The SD automatic dispenser comprises a MD culture medium dispensing module, a CC Petri dish loading carousel, and a stirring device according to the invention. The Petri dish BP shown in the figure is in the pouring position. The MD filling module is configured to dispense a predefined quantity of culture medium into the Petri dish BP by means of a dispensing nozzle. The stirring device DA is configured to allow automatic stirring of the Petri dish (according to the principle described later in relation to the figures 2 to 8), once the MC culture medium has been poured into the PB Petri dish. Once the MC culture medium has been dispensed and agitated, the BP Petri dish is then conveyed to the CC loading carousel to be stacked with the other processed Petri dishes.

[0030] We now present, in relation to the figures 2 to 6 The operating principle of the stirring device according to a particular embodiment of the invention. figures 2 and 3 represent the stirring device when the Petri dish is in the pouring position (known as the "low position"), and the figures 4, 5 And 6 when the Petri dish is in the shaking position (called "high position").

[0031] Note that the Petri dish BP has not been shown in these figures for clarity. However, it is assumed that the pouring of medium MC has already been carried out and that the Petri dish BP contains the medium MC to be stirred.

[0032] The device according to the invention is therefore designed to agitate the Petri dish that has just been poured (i.e., containing the MC culture medium). As an example, the device is programmed so that the agitation time is close to the time required to dispense 20 ml of culture medium (typically about 4 seconds) in order not to reduce the dispenser's speed, hence the need for particularly efficient agitation. Structure of the stirring device

[0033] The device according to the invention comprises mechanical means for moving the Petri dish along a translation axis T between a pouring station for the culture medium ( figures 2-3) and a container stirring station ( figures 4-6 ).

[0034] In this particular embodiment, the mechanical movement means include a helical screw 11, a cylindrical tube (or hollow shaft) 12 cooperating with the helical screw 11 to allow movement of the Petri dish along the translation axis T. The mechanical movement means also include a motor 10 for rotating the helical screw 11. By way of example, the motor 10 is a stepper motor cooperating with the helical screw 11 and whose direction of rotation determines the direction of translation of the Petri dish along the translation axis T.

[0035] The device according to the invention further comprises pneumatic gripping means for the Petri dish, these gripping means being able to assume the following two operating states: a first state (called inactive) in which no grasping of the Petri dish is carried out, and a second state (called active) in which the grasping means ensure the grasping of the Petri dish.

[0036] The gripping means according to the invention are configured to cooperate with the movement means discussed above such that the gripping of the Petri dish is activated as the Petri dish is moved from the pouring station to the stirring station and, conversely, is deactivated as the Petri dish is moved from the stirring station to the pouring station. Thus, when the Petri dish is in the pouring station, no gripping of the Petri dish occurs, and when the Petri dish is in the stirring station, the gripping means ensure the gripping of the Petri dish.

[0037] The gripping means include a pneumatic suction cup 20 and a vacuum assembly cooperating with the suction cup 20 to actuate the suction cup and thus enable the Petri dish to be gripped. As illustrated in the top view of the figure 9The suction cup 20 includes a receiving face FR having a central receiving axis R of the Petri dish (not shown here for clarity). This central axis is designed to coincide with the central axis of the Petri dish (typically circular). To generate particularly effective agitation of the Petri dish, the device is designed so that the central axis R of the suction cup 20 and the translational axis T are not coincident, but parallel and distinct from each other (to allow for eccentricity of the center of the suction cup with respect to the axis T). The vacuum assembly comprises a cylindrical tube 12 and a fixed piston 21 housed within this tube, the cylindrical tube 12 being configured to move in translation relative to the fixed piston 21.

[0038] The stirring device further comprises a plate 25, for example circular in shape, having a lower face fixed rigidly to the cylindrical tube 12 and an upper face fixed to the suction cup 20. In the example illustrated here, the central axis of the plate 25 coincides with the axis of the suction cup 20. The function of this plate 25 is to offset the central axis R of the suction cup by a certain distance from the axis of translation T. The offset provided by the plate 25 ensures an elliptical rotation of the Petri dish during its stirring phase, resulting from a circular rotation of the cylindrical tube around the axis of translation T.

[0039] Thus, when the cylindrical tube 12 rotates around the translation axis T (movement represented by arrow F2), the central axis R of the suction cup 20 rotates around axis T, enabling effective agitation of the culture medium. The rotation of the plate 25 is achieved by rotation means 31 of the movement means, detailed below.

[0040] In this particular embodiment, the rotation means 31 comprise a mechanical gear 31b and a drive motor 31a for this mechanical gear 31b. The mechanical gear 31b cooperates with the fixed assembly consisting of the stepper motor 10, the cylindrical tube 12, and the plate 25, such that when the motor 31a is actuated, the mechanical gear 31b drives the said fixed assembly in rotation around the translation axis T. In this example, the mechanical gear 31b is formed of two gears meshed with each other to transmit the rotational motion of the motor 31a to the movement means. The motor 31a is, for example, a stepper motor whose direction of rotation determines the direction of rotation of the suction cup around the translation axis T.

[0041] The device according to the invention further includes control means 30 of the agitation of the Petri dish, cooperating with the rotation means 31 previously described.

[0042] The following is described in relation to the organizational chart of the figure 7 , The stirring method according to a particular embodiment of the invention. This method mainly comprises a step of gripping the Petri dish (referenced as step 100), a step of stirring the Petri dish (referenced as step 200), and a step of ungripping the Petri dish (referenced as step 300). The method according to the invention is controlled by a control module 80, the principle of which is explained later in relation to the figure 8 . Gripping the Petri dish

[0043] Here, we assume that the Petri dish (containing the culture medium) is placed on the suction cup 20 at the pouring station and that the gripping means are inactive. Upon instructions from the control module, the mechanical movement means are activated to move the Petri dish along the translation axis T from the pouring station ( figures 2-3 ) towards the agitation station ( figures 4-5 Thus, the activation of the stepper motor 10 causes the helical screw 11 to rotate in a direction that allows, by translation of the movable tube 12 relative to the fixed piston 21, the vertical movement of the Petri dish from a "low" position to a "high" position (a movement represented by arrow F1 on the figure 5The tube 12 forms a hermetically sealed enclosure. Furthermore, the translational movement of the tube 12 relative to the piston 21 creates a vacuum between the plate 25 and the suction cup 20, which increases as the Petri dish is moved towards the stirring station. In other words, the translational movement of the tube 12 relative to the piston 21 allows the suction cup 20 to exert an attractive force on the Petri dish that increases as the Petri dish is moved. In the upper position (as illustrated in the Figures 4 and 5 The vacuum between the plate 25 and the suction cup 20 reaches its maximum, and the Petri dish is considered sufficiently attached to the plate 25 to undergo the shaking operation. The Petri dish is then grasped and ready to be shaken.

[0044] Thus, an automated and efficient gripping of the container is cleverly achieved by taking advantage of the mechanical movement of the Petri dish. The use of a suction cup offers a genuine alternative to known prior art gripping solutions. Finally, the movement of the dish not only provides the suction effect but also optimizes the culture medium dispensing process. Indeed, since the Petri dish is agitated outside the pouring station, it is possible to simultaneously agitate the current Petri dish and pour a subsequent Petri dish. Shaking the Petri dish

[0045] Once the Petri dish is grasped, on instructions from the control module, the control means 30 are activated to implement the following sequence of actions: Action 1: Rotation of the suction cup 20 in a first direction of agitation, for example counterclockwise (rotation represented by arrow R1 on the figure 5 Action 2: stop the rotation of the suction cup 20; and Action 3: rotate the suction cup 20 in a second direction of agitation, for example clockwise, taking into account a predetermined time from the stop.

[0046] Therefore, to achieve the first rotation of the suction cup 20, the rotation means 31 are actuated so that the stepper motor 31a drives, via the gear pair of gear 31b, the assembly around the translation axis T in a counterclockwise direction, thus imparting an initial elliptical rotation to the Petri dish in a counterclockwise direction. The rotation speed of the suction cup 20 is, for example, between 50 and 60 rpm. It is chosen to allow an elliptical movement of the Petri dish without causing overflow.

[0047] After a predetermined duration (typically a few seconds), the control module abruptly stops the first rotation movement of the platform by disabling the rotation means 31, so as to generate a wave of the culture medium in the Petri dish.

[0048] After a predetermined duration (typically on the order of a few tens of microseconds), the control module again activates the rotation mechanism 31, but this time causing the Petri dish to undergo a second elliptical rotation, this time in a counterclockwise direction. This duration is calculated so that the culture medium in the Petri dish does not have time to settle. This allows the presence of the wave in the culture medium to be used for effective agitation. The rotation speed of the suction cup 20 is, for example, between 50 and 60 rpm, to allow for an elliptical movement of the Petri dish (and therefore effective agitation) without causing overflow.

[0049] The elliptical rotation of the Petri dish and the abrupt change in direction of rotation ensure efficient and rapid agitation of the poured culture medium. Petri dish depreciation

[0050] Once the Petri dish has been agitated, as instructed by the control module, the mechanical means are activated to move the Petri dish along the translation axis T from the stirring station to the pouring station. Thus, the activation of the stepper motor 10 causes the helical screw 11 to rotate in the opposite direction to that used in step 100 of the process. This, in turn, by translation of the tube 12 relative to the piston 21, causes the Petri dish to move vertically from the stirring station (high position) to the pouring station (low position). The reverse movement of the tube 12 relative to the piston 21 allows for a return to normal atmospheric pressure by increasing the pressure between the plate 25 and the suction cup 20 as the Petri dish is moved towards the pouring station.In other words, the movement of tube 12 relative to piston 21 allows suction cup 20 to release the attractive force exerted on the Petri dish as it moves. In the lowered position (as illustrated in the diagrams). figures 2 and 3 ), the depression existing between the plate 25 and the suction cup 20 reaches its minimum, i.e. a return to normal atmospheric pressure which allows the Petri dish to be released.

[0051] Thus, an automated and efficient degripping of the container is also cleverly achieved by taking advantage of the mechanical movement of the Petri dish.

[0052] The embodiment described above relies on the use of a vacuum suction cup shaped to grip Petri dishes. This illustrative example is not limiting, and the device of the invention can be equipped with a plurality of suction cups, which can be of different sizes and arranged in a geometric configuration adapted to the shape of the container to be gripped.

[0053] Note that the agitation sequence described above is provided as a specific example of the process. The nature and order of the actions within the agitation sequence, as well as the parameter values ​​used (speed and duration of each action), can of course be adapted according to the requirements and the challenges of homogenizing the poured medium. Performing several iterations of the same given sequence can also be considered, without departing from the scope of the invention. For example, the aforementioned sequence of movements (actions 1 to 3) can be repeated several times to further improve agitation efficiency, for instance, in the case of viscous or poorly miscible culture media.

[0054] There figure 8 represents the simplified structure of a control module 80 implementing the method of the invention (for example, the particular embodiment described above in relation to the figures 2 to 7This device comprises a random access memory 83 (e.g., RAM), a processing unit 81, equipped, for example, with a processor, and controlled by a computer program stored in a read-only memory 82 (e.g., ROM or a hard drive). At initialization, the code instructions of the computer program are, for example, loaded into the random access memory 83 before being executed by the processor of the processing unit 81. The processing unit 81 receives as input 84 a command to initialize the stirring process. The processor of the processing unit 81 processes the command and generates as output 85 the control commands intended for the various elements of the control device, according to the instructions of the computer program (gripping command, stirring command according to the predefined sequence, degripping command).

[0055] This figure 8illustrates only one particular way, among several possible ways, of implementing the various algorithms detailed above, in relation to the figures 2 to 7 Indeed, the technique of the invention can be implemented indifferently: on a reprogrammable computing machine (a PC, DSP processor, or microcontroller) running a program comprising a sequence of instructions; or on a dedicated computing machine (e.g., a set of logic gates such as an FPGA or ASIC, or any other hardware module).

[0056] In the case where the invention is implemented on a reprogrammable computing machine, the corresponding program (i.e. the sequence of instructions) may be stored in a removable storage medium (such as, for example, a floppy disk, a CD-ROM or a DVD-ROM) or not, this storage medium being readable partially or totally by a computer or a processor.

Claims

1. A shaker device (DA) for shaking a container for a culture-medium dispenser, wherein said container is intended to contain a culture medium to be shaken, wherein the device is characterised in that it comprises: - mechanical movement means (10, 11, 12) for moving said container along a translation axis (T) which are configured to move said container between a pouring station and a shaking station; - gripping means (20, 21) for gripping said container which are capable of assuming at least two operating states: a first state, called the inactive state, in which no gripping of said container occurs, and a second state, called the active state, in which said gripping means grip the container, wherein said gripping means are configured to cooperate with said movement means in such a manner that the gripping of the container is activated as said container is moved from the pouring station to the shaking station and is deactivated as the container is moved from the shaking station to the pouring station; - control means (30) for controlling the shaking of said container, i.e. the gripped container, which are activated when said gripping means are in the second state, characterised in that the control means include rotation means for rotating the mechanical movement means about the translation axis (T) and said gripping means include at least one pneumatic suction cup (20) with a central receiving axis (R) for receiving said container, wherein said at least one suction cup (20) and said mechanical movement means are arranged so that the central receiving axis (R) and the translation axis (T) do not coincide with each other.

2. A device according to claim 1, including a decentring plate (25) for decentring said at least one suction cup (20), wherein said plate (25) has a lower face rigidly attached to said mechanical movement means and an upper face attached to said at least one suction cup (20).

3. A device according to any one of claims 1 and 2, wherein the control means are configured to control the rotation means so as to enable at least one iteration of the following sequence: - first rotational movement about the translation axis; - stopping the first rotational movement; and - second rotational movement about the translation axis in a direction of rotation opposite to the first movement that takes into account a predetermined duration from the moment of stopping.

4. A device according to any one of claims 1 to 3, wherein: - the mechanical movement means include a helical screw (11), a cylindrical tube (12) that cooperates with said screw to enable a movement of the container along the translation axis (T), and a rotary drive motor (10) for rotating said helical screw; - the gripping means further include an assembly for creating a negative pressure which cooperates with said at least one suction cup (20) to actuate said at least one suction cup, wherein said assembly is formed by a fixed piston (21) and said cylindrical tube (12), which cylindrical tube (12) is movable in translation relative to the piston (21).

5. A culture-medium dispenser characterised in that it includes a shaker device (DA) according to any one of claims 1 to 4.

6. A method for shaking a container for a culture-medium dispenser, wherein said container contains a culture medium to be shaken, wherein the method is characterised in that it comprises the following steps: - gripping (100) said container by mechanically moving said container from a pouring station, in which no gripping of said container occurs, to a shaking station, in which said container is gripped; - shaking (200) said gripped container; - releasing (300) said container by mechanically moving said container from the shaking station to the pouring station; - characterised in that the shaking step includes at least one iteration of the following sequence: - first rotation of the mechanical movement means in order to produce a first elliptical shaking movement for shaking said container; - stopping the first rotation; - second rotation of the mechanical movement means in a direction of rotation opposite to the first rotation in order to produce a second elliptical shaking movement for shaking said container in a direction opposite to the first movement, wherein the second rotation is carried out before a predetermined duration from the moment of the stopping of the first rotation has elapsed.

7. A method according to claim 6, wherein said sequence is iterated multiple times.

8. A computer program product, including program code instructions that cause the shaker device according to claims 1 to 4 to implement the method according to at least one of claims 6 to 7 when said program is executed on a computer of said device.

9. A non-transitory, computer-readable storage medium that stores a computer program product according to claim 8.

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