Laboratory mixer

A laboratory mixer for mixing a sample and a diluent in a bag. An enclosure defines a mixing chamber, and at least one movable mixing element is retained for mixing the sample and the diluent within the bag. At least one liquid detector is retained relative to the enclosure for detecting liquid leaked from the bag. The sensor can be a capacitive, inductive, or optical sensor. The sensor can be a conductivity sensor with two electrodes shaped like combs and a gap less than or equal to a diameter of a drip of diluent solution. A ledge with a low point can be retained by an access door. The sensor or sensors can be disposed adjacent to the access door, on a mixing element, in direct contact with the bag, or on a tank. An alarm and cessation of operation can be triggered upon a detection of leaked liquid.

RELATED APPLICATION

This application claims priority to French Application No. 1361085, filed Nov. 13, 2013.

FIELD OF THE INVENTION

The present invention relates generally to devices for use in analytical laboratories of the food, medical, cosmetic, chemical and pharmaceutical industries. More particularly, disclosed herein is a blade mixer for use in the preparation of microbiological samples contained in bags that are being prepared to be analyzed.

BACKGROUND OF THE INVENTION

Different types of laboratory mixers for the preparation of samples are known. Certain mixers are designed for the preparation of a sample before its microbiological analysis.

Typically, preparation of a sample to be analyzed begins with inserting the sample into a flexible sterile bag, usually made of a transparent plastic material. A diluent solution, usually physiological serum, is added to the bag. A supporting device, such as a blade mixer, can then be situated on a static surface and operated horizontally against the bag containing the sample to be analyzed.

The mechanism of a typical mixer consists of two blades. The blades grind the sample, if it is a solid, to homogenize the sample prior to microbiological investigation. However, the samples to be analyzed are often of various dimensions with varying external surfaces that may be sharp and jagged. As a result, the sterile bag may be pierced or a leak may be caused. In this regard, it will be noted that any contact between the sample and the inner parts of the mixer causes cross contamination. As a consequence, the entire preparation process must be restarted from the beginning, and the interior of the mixer must be completely cleaned.

A number of inventors have sought to provide improved mixers. Often, such inventors seek as a fundamental goal to preserve the integrity of the sample.

For example, French Patent No. 2795658 B1 describes a mixer that allows the mechanical action of the blades to adjust to the dimensions of the sample. With that, deterioration of the sterile bag is sought to be prevented. However, any adjustments are made at the discretion of the operator and are not guaranteed to be accurate or beneficial. Consequently, despite the adjustments, the mechanical action may still lead to leaks and accidental perforation.

In view of the foregoing, it will be appreciated that there is a continued need for a laboratory mixer for samples that enables an effective mixing of samples while avoiding piercing and other damage to the sample container and while preventing sample and apparatus contamination.

SUMMARY OF THE INVENTION

Accordingly and in view of the recognized and continuing needs relating to the preparation of microbiological samples, the present invention is founded on the basic object of providing a system and method for facilitating the preparation of microbiological samples contained in bags that avoids loss and contamination from piercing, leaking, and rupturing of sample containers, such as sample bags.

A further object of embodiments of the invention is to provide a system and method for the preparation of microbiological samples contained in bags that is efficient and reliable in operation.

Another object of certain embodiments of the invention is to provide a system and method for the preparation and mixing of microbiological samples that minimizes the need for remedial cleaning of the laboratory mixer and surrounding components and structures.

Still another object of embodiments of the invention is to provide a system and method for the preparation and mixing of microbiological samples that avoids waste and conserves time.

These and further objects and advantages of the present invention will become obvious not only to one who reviews the present specification and drawings but also to those who have an opportunity to experience an embodiment of laboratory dispenser disclosed herein in operation. However, it will be appreciated that, although the accomplishment of each of the foregoing objects in a single embodiment of the invention may be possible and indeed preferred, not all embodiments will seek or need to accomplish each and every potential advantage and function. Nonetheless, all such embodiments should be considered within the scope of the present invention.

In carrying forth the aforementioned objects, one practice of the invention involves the preparation of samples contained in bags wherein a bag can be inserted into an enclosure delineating a mixing chamber. The bag and its relationship with the enclosure can be tight, and the bag can contain a sample and a diluting solution. The mixer has mixing features to mix the contents of the bag, such as the sample and the diluting solution. Even in basic embodiments, the mixer introduced in this invention offers to its users more efficiency in the preparation process of samples to be analyzed with an increased reliability of homogenization prior to sample analysis.

The laboratory mixer can further include one or more liquid detectors, which can be within the mixer enclosure. Preferably, the liquid detectors include at least one sensor located inside the mixer enclosure. It or they can be found in different locations or on different elements inside the mixing chamber. At least one sensor can be positioned in a pertinent position to quickly detect a loss of diluent solution. In this regard, it will be noted that, in the event of a puncture in the bag and due to movements of the mixing devices, the diluent solution can be projected in different directions. According to the invention, at least one of the sensors can be chosen from the group consisting of capacitive, inductive or optical sensors.

Advantageously, at least one sensor can be a conductivity sensor. Embodiments are contemplated wherein the sensor includes at least two electrodes forming an interval of at least one turn. This configuration is particularly adapted to this laboratory mixer application. It is further contemplated that the diluent solution could be salted thereby to conduct electricity. Advantageously, two comb-shaped electrodes could be interleaved. The electrodes could define a sinuous interval.

Preferably, at least one sensor can have two electrodes separated by a gap, which can represent the width of an interval, inferior or equal to the diameter of a drip of the diluent solution. In particular practices of the invention, the gap between two interleaved comb-shaped electrodes can be from 0.5 to 10 millimeters, even more preferably between 0.5 and 1.5 millimeters. In one further option, at least one of the interleaved comb-shaped sensors can be of random dimensions. In a still further option, at least one of the sensors can be equipped with gold-plated contacts.

Optionally, the current that goes through one of the sensors could be of low voltage. Additionally or alternatively, the current can be sent using impulsions to avoid corrosion. The current could be successively sent to the sensor, one terminal before the other, to avoid electrolyzing.

Preferably, the sensor can be fixed on a flexible substrate mounted on a mobile element of the mixer. The substrate can be extended by a tab supporting conductors connecting the sensor to electrical means installed in a fixed position in the mixer.

It is contemplated that the liquid detection sensors can be located on an access door within the enclosure, preferably located at a vertical median line of the door. It is further contemplated that one or more liquid detectors can be located on a ledge located inside the enclosure to support the bottom of the bag. This ledge can lead the dripping of the diluent solution to at least one collecting tank and one sensor.

The ledge can offer a low point, and liquid detection means can be located on it. The ledge can, in certain embodiments, be valley-shaped. For example, the ledge can be shaped like a V, the low point being the bottom of the V. The V-shape improves the draining of the diluent solution along the ledge to at least one of the sensors. The bottom of the V can correspond to a discharge manifold. In addition, the ledge can have at least one flange along the outer edge of the ledge opposite a bearing surface. The at least one flange helps guiding more diluting solution from the outer shell of the bag and the ledge to at least one sensor, thus preventing the diluent solution from dripping straight into the tank. The discharge collector guides the flow of the diluent solution once it has gone through at least one sensor.

Optionally, one or more liquid detectors can be located on at least one surface delineating the mixing chamber and adjacent to an access door of the enclosure, preferably near to the door. For example, one or more liquid detectors can be located on the same level with the mixing apparatus when they are fully deployed and operative, such as in direct contact with the bag.

Optionally, the liquid detector or detectors can be located directly on the mixing means. In fact, after a bag has been pierced due to movements of the mixing means, the diluent solution can spread on the bag and/or been projected on them. Preferably, mixing apparatus includes blades.

As taught herein, one or more liquid detectors can be in direct contact with the bag. Such a position grants an almost instantaneous detection of a leak, for at least one sensor is disposed in a pertinent manner. Still further, one or more liquid detectors can be located on at least one tank designed to collect leaks should a bag become breached.

Optionally, one or more liquid detectors can be located in a ledge tank, near the bottom of the V if it is a V-shaped ledge. In such embodiments, at least one sensor can be included that would require being fully-immersed or just a certain quantity of diluent solution to detect the leak. This embodiment also protects at least one sensor from any damage that could be inflicted, such as by a sharp sample, and this thanks to the relative distance between the bag and the bottom of the ledge tank. Such embodiments ease cleaning, avoiding spilling the diluent solution about the mixing chamber or the elements composing and within it.

Also according to this invention, one or more liquid detectors can activate, as soon as a leak of liquid is validated, an audible and/or visual alarm and/or an interruption of the mixing apparatus. The user can thus be warned of the failure of the sample preparation process without having to wait for it to end.

These features give to the invention several benefits. First, laboratory mixers embodying the invention improve the efficiency of the preparation process. In fact, the user will not lose time waiting for a sample that has become unusable. Moreover, the detection of leaks prevents from any excessive contamination of the mixing chamber and thus offers a gain of time when it comes to cleaning. In case the mixing process can be directly seen by the user, the user does not have to overview the process which may imply the possibility to work in masked-time. In addition, if the leak detection comes quickly, such as at the beginning of the mixing process, the sample may still be usable for a new preparation. On the other hand, mixers according to the invention can guarantee the reliability of the homogenization of the sample and the diluent solution. For example, mixers as taught herein can prevent the user from accidentally moving a leaking bag, which is contaminated, to another work station, in the perspective of the analysis for example.

One will appreciate that the foregoing discussion broadly outlines the more important goals and features of the invention to enable a better understanding of the detailed description that follows and to instill a better appreciation of the inventor's contribution to the art. Before any particular embodiment or aspect thereof is explained in detail, it must be made clear that the following details of construction and illustrations of inventive concepts are mere examples of the many possible manifestations of the invention. It will thus be clear that additional features and benefits of the invention will be apparent through a reading of the detailed description of implementations and embodiments, which are without restriction, and by reference to the attached figures.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The system and method for the preparation of microbiological samples disclosed herein is subject to a wide variety of embodiments. However, to ensure that one skilled in the art will be able to understand and, in appropriate cases, practice the present invention, certain preferred embodiments of the broader invention revealed herein are described below and shown in the accompanying drawing figures. Therefore, before any particular embodiment of the invention is explained in detail, it must be made clear that the following details of construction and illustrations of inventive concepts are mere examples of the many possible manifestations of the invention. The embodiments disclosed herein should not be considered as limiting. Indeed, variants of the invention are readily possible that would include only a selection of the features shown and described apart from the other described features.

Looking more particularly to the drawings, an embodiment of the invention disclosed herein is depicted inFIGS. 1 through 3in the form of a mixer for sample preparation, which is indicated generally at1. The illustrated mixer1includes mixing members5positioned in a mixing chamber3and delineated by an enclosure2. The mixing members5allow a bag10and the contents of the bag10, such as a sample and a diluent solution, to be pressed, retained, and ultimately mixed by a pressing against a supporting surface43of the enclosure2in the mixer1. The bag10can, for instance, be seen inFIGS. 2 and 3.

The mixing members5in this embodiment can be reciprocated toward and away from the supporting surface43to selectively, and with adjustable pressure, compress the bag10and its contents against the supporting surface43and, in doing so, to mix the contents of the bag10. In the present embodiment, the mixing members5are plates or blades whose contact surfaces with the bag10are generally parallel to the supporting surface43. The mixing members5may alternatively be referred to as retaining elements, plates, or blades or mixing plates or blades5.

The operation of a mixing member actuation and control apparatus51can be such that, when one mixing member5moves toward the support surface43and increases its compression of the bag10, another mixing member5can deviate away from the supporting surface43and decrease its compression of the bag. As one skilled in the art will readily appreciate by reference to the present disclosure, the actuation and control apparatus51could pursue multiple different forms within the scope of the invention. The actuation and control apparatus51can selectively reciprocate or otherwise move the mixing members5in an alternating, simultaneous, intermittent, continuous or other movement pattern.

In the present embodiment, the mixing members5consist of two mixing plates or blades. At least in certain practices of the invention, the supporting surface43and the mixing members5can be generally vertically disposed with generally vertically disposed plate surfaces. A tank6can be positioned below the mixing members5to collect leakage from the mix of the sample and diluent solution.

In a preferred embodiment, the enclosure2of the mixer1can retain an access door4. The access door4can be designed as an access path to the mixing chamber3and can retain the supporting surface43. As depicted inFIG. 3, for example, the door4, which can be a glass door, is positioned vertically when closed for mixing, and pivots downwardly about a horizontal hinge axis to reach an opening position, such as a position of a 70° inclination, to permit insertion and removal of a bag10as shown, for instance, inFIG. 2, and even to a horizontal position for cleaning as shown, for instance, inFIG. 1.

In certain embodiments of the invention, one or more liquid detectors20can be located inside the enclosure2of the mixer1to detect liquids, such as the diluent solution, that may have leaked outside of the bag10. The liquid detector or detectors20can include at least one sensor21practically positioned and retained to increase its chances of being in contact with any diluent solution dripping from a bag10that is breached during mixing. In such a situation, the sensor21can transmit a signal to a controlling system, which can include an electronic card, to trigger, for example, cancellation of the mixing operation and/or an audible and/or a visual alarm to alerts the user that preparation has failed.

In the present embodiment, the door4, as shown for example inFIGS. 1 to 3, retains a ledge41. The ledge41can act as a vertical support for the bottom of the bag10during mixing. The ledge41can hold the bag10in position against the operative mixing members5. The ledge41could, for example, extend generally perpendicularly from the supporting surface43of the door4.

By way of example and not limitation,FIG. 2shows a user inserting a bag10containing a sample and a diluent solution along an insertion path generally indicated at11. The diluent solution could generally be a saline solution, such as physiological serum. The bag10can be inserted into the mixer1to permit a homogenization of the mixture before microbiological analysis. As a result of the door4being able to be opened, the user may slide the bag10along the door4to the ledge41. The user can then close the door4of the mixer1before activating the mixing members5.

In the present embodiment of the broader invention disclosed herein,FIG. 3shows the mixer1as it might appear during the mixing process. The door4is closed, and the bag10is in contact with the door4, the ledge41, and at least one of the mixing members5. During operation of the mixer1, the mixing members5can intermittently, alternatingly, or otherwise press against the bag10along a generally horizontal trajectory, compressing it against the supporting surface43of the door4. The sample can then be gradually grinded after each successive contact by the mixing members5and diluted in the diluent solution by means of the homogenization process.

In the event of a leak, such as if the bag10is pierced by a sharp-edged sample, the diluent solution will, due to gravity, tend to drip down the bag10and/or from the ledge41to reach at least one sensor21, which again can be positioned to be below the bag10during operation of the mixer1. In this way, it is possible to notice any loosely or poorly sealed bags, as well as any punctured or otherwise compromised bags, quickly thereby to minimize cleanup and wasted time and material.

The ledge41can be located at a given height from the bottom of the mixer1. The ledge6can overlie the tank6in such a manner that any leaking solution not retained by the ledge41will tend to flow into the tank6located at the bottom of the mixing chamber3.

The inner face of the access door4can be seen perhaps most clearly inFIG. 4. There, one can see the ledge41affixed to the inner face of the access door4. In the present embodiment, the ledge41, more particularly at least the upper face of the ledge41, can be seen to have a low-point44where any leaking liquid would tend to gather. In this example, the low-point44is located in an intermediate position, preferably at about midway along the ledge41. For example, the ledge41can be shaped in a V-shape and can offer two slopes of similar length and steepness. The ledge41thus offers a support to the bottom of the bag10against gravity while controlling the flow of diluent solution or the sample mixed with it in case of a leak or a burst.

In a preferred embodiment, at least one sensor21can be located at or near the low-point44of the ledge41. The sensor21can have a sensing face horizontally turned face-up. The ledge41can be channel-shaped and can offer one or more outboard ridges or sills42opposite to the supporting surface43. In case of a leak, the sills42can offer better guidance of liquid dripping from the bag10and the ledge41toward the at least one sensor21. With that, the chances of an early detection of any leak of liquid is increased, and diluent solution is guided toward but does not arbitrarily leak directly into the tank6. Consequently, the intersection of the two slopes of the ledge41corresponds to a discharge collector with the ledge41acting as a through-way or a spillway.

With reference toFIG. 5, the sensor or sensors21could, for example, be an electrically conductive sensor21. The sensor21can, by way of example and not limitation, include two electrodes24fixed on an isolating substrate22that are normally isolated from one another. A gap26is established between the electrodes24. When a drip of liquid bridges the gap26, it connects the electrodes24electrically. A current is sent from one electrode24to the other and can be detected by an electrical monitoring system29of the mixer1, which is shown schematically. This detection can generate the emission of an alarm signal from an alarm30and, additionally or alternatively, a shutdown of the mixing members5.

The gap between the two electrodes24, which means the width of the gap26, can be less than or equal to the diameter of a drip of the diluent solution. This way, any drip can be detected, and the mixing members5can be stopped instantly, whether manually by a user or automatically. Leaking diluent solution can be prevented from continuing to spread in the mixing chamber3.

The form of the electrodes24can be chosen so that the developed length of the gap26would as great as possible. The gap26can, for example, be made of one or several turns or even a sinuous shape of electrically conductive material. In the example depicted, each electrode24has a comb shape and the two combs face each other, interleaved to define a gap26that is sinuous and of a roughly equal width. Conductors27can connect the electrodes24to the electrical monitoring system29located in the mixer1.

In the present embodiment, where one or more sensors21are mounted on a movable element, such as the door4, the sensor21, more particularly the electrodes24of the sensor21, is fixed on a flexible substrate22which is itself mounted on the ledge41as can be seen in the cross-sectional view ofFIG. 6. The substrate22is extended by a flexible tab23that supports the conductors27, made flexible, and connecting the sensor21to the electric monitoring system29installed in a static position in the mixer1. Also with reference toFIG. 6, starting from the sensor21, the tab23bearing the conductors27can go to the articulation axis of the door4and form around it a loop28that can bend elastically when the door4is manipulated. In embodiments of the laboratory mixer1, one or more sensors21can be chosen from the group formed by capacitive, inductive, and optical sensors.

It is also contemplated that at least one sensor21can be retained on one of the surfaces delineating the mixing chamber3adjacent to the door4. For example, as shown inFIG. 7, a sensor21can be located on each lateral wall of the mixing chamber3adjacent to the door4. The sensor or sensors21can be close to the door4and, additionally or alternatively, near the mixing members5when they are on deployed in position for operation in contact with the bag10. This embodiment is especially advantageous in case the bag10bursts and diluent solution is sprayed about the chamber3.

In another embodiment, a sensor21can be mounted on a mixing member5or on each one of the mixing members5as shown, for instance, inFIG. 7. Thus, the sensor or sensors21can be disposed on one or both of the mixing elements5and, thus, in direct contact with the bag10during operation of the mixer1. A sensor21could also be located on, in, or at the bottom of the tank6, such as directly below a discharge drain of the ledge41. The sensor21can be movable to enable extraction from the tank6. One or more sensor21could additionally or alternatively be set on the door4. Such a sensor21could extend the entire width of the door4so that, wherever the liquid may drip along the door4, it would be detected. It is also within the scope of the invention, except as it might be expressly limited by the claims, for the electrodes24to be shaped in spiral form. In such embodiments, each loop of a first spiral can extend between two successive loops of a second spiral. Still further, at least one sensor21could be movable between two preparations.

With certain details and embodiments of the present invention for a laboratory mixer disclosed, it will be appreciated by one skilled in the art that changes and additions could be made thereto without deviating from the spirit or scope of the invention. This is particularly true when one bears in mind that the presently preferred embodiments merely exemplify the broader invention revealed herein. Accordingly, it will be clear that those with certain major features of the invention in mind could craft embodiments that incorporate those major features while not incorporating all of the features included in the preferred embodiments.

Therefore, the following claims are intended to define the scope of protection to be afforded to the inventor. Those claims shall be deemed to include equivalent constructions insofar as they do not depart from the spirit and scope of the invention. It must be further noted that a plurality of the following claims may express certain elements as means for performing a specific function, at times without the recital of structure or material. As the law demands, these claims shall be construed to cover not only the corresponding structure and material expressly described in this specification but also all equivalents thereof that might be now known or hereafter discovered.