Solution preparation device, solution preparation system, and method of preparing a solution using the solution preparation system

Abstract

The present application relates to a solution preparation device, a solution preparation system and a method of preparing a solution using the solution preparation system. The present application particularly relates to an automated solution preparation device, system and method, in particular for preparing a solution like a buffer, for use in chemical, biochemical and biological applications.

Description

[0001] SOLUTION PREPARATION DEVICE, SOLUTION PREPARATION SYSTEM, AND METHOD OF PREPARING A SOLUTION USING THE SOLUTION PREPARATION SYSTEM

[0002] Technical Field

[0003] The present application relates to a solution preparation device, a solution preparation system and a method of preparing a solution using the solution preparation system. The present application particularly relates to an automated solution preparation device, system and method, in particularfor preparing a solution like a buffer, for use in chemical, biochemical and biological applications.

[0004] Background

[0005] The fabrication or preparation of solutions like buffers in chemistry, biochemistry or biological laboratories is a common activity. A buffer is an aqueous solution used as a means to maintain the pH of the solution within a narrow range. The preparation of a buffer is a preferred use but the present device, system, and method may also be applied more generally to any solutions used in chemical, biological and biochemical applications and uses. For the purposes of the present application, the preparation of a buffer is nevertheless used as an illustrating example for describing the present device, system, and method.

[0006] The process of preparing a solution requires precise control of the amounts of substances or compounds going into a solution according to a particular formulation, and possibly also of a variety of parameters, such as temperature, conductivity, and / or pH.

[0007] Up to now, the preparation of solutions like a buffer is mainly done manually. The preparation process may generally comprise the following steps:

[0008] • different powders are weighed and dissolved in pure water;

[0009] • the solution is mixed to reach full dissolution;

[0010] • one or more liquid reagent is added as desired;

[0011] • the solution is transferred to a volumetric flask and the volume is adjusted;

[0012] • optionally, the pH may be adjusted by dispensing drops of acid or base in the solution, determining the pH with a pH meter;

[0013] • optionally the solution may be filtered through a sterile membrane (0.22 pm), or be subjected to a non-sterile filtration for particle removal only, and the solution may eventually be transferred to a storage bottle or container for subsequent use in any of the above-mentioned applications and uses.

[0014] This manual preparation requires the handling of a significant number of different pieces of equipment (for example, pH-meter, stirrer, pipettes, weighing devices (scales), dissolution beaker, volumetric flask, buffer storage bottle), intermediate manual glassware rinsing, and sample transfers, leading to significant complexity of the process as well as a rather high workload for laboratory technicians, not to forget having to clean the equipment after use. In consequence such manual preparation carries a not insignificant risk of errors. Using intermediate glassware, spatulas and scoops are a source of potential contamination and generates waste.

[0015] Moreover, manual preparation brings with it the risks of contact with hazardous chemicals during weighing and transfer. Powders and other reagents can be volatile and may need to be handled using adequate individual protective equipment (gloves, masks, glass) and / or under collective protective equipment (laminar hood, clean room).

[0016] To avoid or at least reduce the disadvantages of manual preparation, partially automated solutions are available, particularly for use in laboratories having a high consumption of such solutions. Alternatively, one can turn to ready-to-use buffer solutions or preformulated buffer tablets, which may be dissolved in a specified volume of water, thereby allowing to essentially avoid all chemical handling and weighing processes.

[0017] Automatic titrators exist but they only adjust the pH and do not propose the mixing or powder delivering. Devices for dosing powder and liquid exist, too, but are high precision and expensive equipment. They are designed for standard preparations of small volumes.

[0018] WO 2012 / 098403 Al discloses an automated solution dispenser for dispensing a solution having a defined list of characteristics, the characteristics comprising one or more characteristics selected from the group comprising pH, temperature, chemical composition. The dispenser comprises a mixing chamber, at least one controllable inlet port to the chamber for controllably receiving components to be mixed into a solution, at least one input sensor for determining a quantitative input of the components to be mixed into the solution, agitation means for agitating the received components, at least one solution sensor for sensing one or more characteristics of the solution, an outlet port coupled to the mixing chamber, a controllable outlet port valve for controlling the flow of solution through the outlet port, and a controller coupled to the at least one controllable inlet port, the at least one input sensor, the agitator, the at least one solution sensor, and the outlet port valve. The controller is configured to measure the received components, mix the received components into a solution and dispense the solution, wherein the at least one controllable inlet port comprises a controllable solids port for controllably supplying solid components to the mixing chamber from one or more solid sources, the controllable solids port comprising a solids dispensing system engageable with a solids dosing mechanism for controllably dispensing a dosed amount of a solid from a solid source. A similar automated solution dispenser is also disclosed in US 2015 / 0314246 Al.

[0019] To date, the previously cited devices and procedures are not satisfactory: manual preparation requires significant time and effort, is in general a burden on laboratory technicians and is a source of errors. The fully automated devices are too complex and are not flexible enough. They occupy a large footprint and represent a high capital expense. They also rather relate more to well-established routine processes of solutions preparation. Hence, these expensive pieces of equipment are rarely used in the general laboratories.

[0020] US 7,040,800 B2 discloses a plate shaped flat magnetic stirrer with a stirring drive in the form of four alternately excitable magnetic coils that have an axial dimension that is smaller than their diameter. The magnetic coils are arranged with their axes parallel to each other and their axial driving ends arranged as close as possible underneath and facing an upper cover made from non-ferromagnetic material on which an external container holding the goods to be stirred as well as a stirring magnet are to be placed. Because the magnetic field is radiated in the whole vertical space above the magnetic coils, the loss of the magnetic field and thus the energy consumption is high.

[0021] US 2006 / 0126431 Al discloses a portable stirring cup which is intended for domestic use in order to mix beverages without the use of a spoon, for example in a car. The stirrer includes a blade paddle actuated through a shaft driven by a rotating motor. This concept cannot be used on a weighing instrument (scale) since such a rotating motor actuating a shaft and a paddle causes significant vibration, making this cup incompatible with a laboratory sub-gram weighing activity. The noise generated by the vibration does not permit precise and fast weight measurement. Moreover, in order to perform a large range of powder dosage, a fast response time is required, thus eliminating slow averaging filtering. Moreover, such a design requires a specific liquid seal in the bottom portion of the cup through a sealed orifice for the rotating shaft. Commonly used elastomeric materials are not suitable due to a lack of chemical resistance and may leach organic traces into the solution prepared in the cup. Further, due to the presence of the shaft and motor, the fluid in the cup cannot be evacuated through the bottom of the cup, thereby - when needing to transfer the solution from the cup into a different vessel, for example, a storage vessel - either leading to dripping of potentially hazardous solutions or chemicals or requiring the use of further equipment, for example, a funnel.

[0022] The present application aims at providing a solution preparation device that can be used to facilitate at least some steps of a manual preparation process, and a flexible solution preparation system suitable to cooperate with the solution preparation device. The present application also aims at providing an improved method of preparing a solution like a buffer using the solution preparation system.

[0023] Summary

[0024] It has now surprisingly been found that the above-indicated objectives may be achieved either alone or in any combination by the present solution preparation device, the present solution preparation system, and the present method of preparing a solution, preferably a buffer solution, using said solution preparation system.

[0025] Hence, the present application provides for a solution preparation device comprising: a portable bowl / container capable of holding a defined volume of a solution in an interior space of the bowl; a magnetic bar movably provided in a bottom portion of the interior space of the bowl; and a stator included in a bottom portion of the bowl external to the interior space of the bowl and configured, in conjunction with a circuitry, to create a rotating magnetic field for rotating the magnetic bar in the bowl so as to form a magnetic stirrer.

[0026] Additionally, the present application provides for a solution preparation system comprising: a solution preparation device as described above; a scale on which the solution preparation device is placed; and one or more dispensers for selectively supplying water and / or a powder and / or a liquid into the interior space of the bowl of the solution preparation device when placed on the scale. The present application also provides for a method of preparing a solution, preferably a buffer solution, using such a solution preparation system, the method comprising: selecting a set of instructions for preparing a solution from one or more compounds including the liquid and / or the powder presented on the user interface; arranging the solution preparation device on the scale; prefilling the bowl of the solution preparation device with pure water through one of the dispensers and determining the mass of the water while dispensing by weighing the bowl; and dosing the powder and / or the liquid equivalent to the determined mass of the water through the one or more dispensers, preferably while mixing the solution in the bowl by operating the magnetic stirrer.

[0027] Brief description of the drawings

[0028] Preferred embodiments of the present device and system will now be described with respect to the attached exemplary, schematic, and non-limiting drawing in which:

[0029] Figure 1 is a schematic partial diametrical cross-sectional view of the lower part of the solution preparation device according to an embodiment;

[0030] Figure 2 is a schematic top view of the magnetic stirrer in the lower part of the solution preparation device according to the embodiment;

[0031] Figure 3 is a schematic diagram of the basic functional elements of the solution preparation system according to an embodiment;

[0032] Figure 4 is a perspective representation of an embodiment of the solution preparation system and a perspective detail view from below of a variant of a dispenser head;

[0033] Figure 5 is a perspective view from the side and from below of another variant of the dispenser head;

[0034] Figure 6 is a perspective view from the side of a solution preparation system and yet another variant of the dispenser head;

[0035] Figure 7a is a cross sectional view of elements for implementing a powder delivery function in a dispenser head;

[0036] Figure 7b is a perspective view of elements for implementing a powder delivery function in a dispenser head;

[0037] Figure 8 is a schematic cross-sectional view of the solution preparation device (bowl) with a pH sensor plugged into a connector; and

[0038] Figure 9 is a perspective view of the solution preparation device (bowl) integrated with a filtration device. Detailed description

[0039] In particularthe present application provides for a solution preparation device comprising a portable bowl capable of holding a defined volume of a solution in an interior space of the bowl (a magnetic bar may be movably provided in a bottom portion of the interior space of the bowl) and a stator included in a bottom portion of the device external to the interior space of the bowl and configured, in conjunction with a circuitry, to create a rotating magnetic field for rotating the magnetic bar in the bowl so as to form a magnetic stirrer.

[0040] The present application thus also provides for a portable bowl capable of assisting the chemical solution (buffer) preparation. The solution can be prepared in the bowl (with a preferred volume that is smaller than 5 liters) that can be washed and dry stored as a unit like regular laboratory glassware. The integration of the stirrer with the bowl (e.g., the stator is included (housed) in the bowl) to form a portable device reduces and simplifies the handling steps during the solution (buffer) preparation following a particular formulation.

[0041] The mixing is based on two components: the magnetic bar which is the moving part and the stator. In order to save energy and reduce mechanical interference which could lead to noise on a weight measurement (when the device is placed on a weighing scale) or an excessive stabilization time, the stator is in the form of the magnetic coils. Moreover, this arrangement may reduce vibration during mixing compared to a motor shaft rotating magnet and the internal weight and footprint of the bowl. Further, the integration of the magnetic coil and the magnetic bar in the same device has limited the magnetic energy field required because the distance between the magnetic coil and bar can be reduced.

[0042] Moreover, the stirrer has no wearing parts, it does not require maintenance, and it can operate at a reduced energy consumption and heating of the solution while providing a high mixing efficiency and a high vortex suitable for a relatively large volume. As compared to a motor shaft rotating magnet, the bottom portion of the bowl is not occupied by a seal for the shaft and thus allows filtration and transfer of the solution at the bottom of the bowl.

[0043] Preferably, the solution preparation device further comprises a pH sensor provided on the bowl, preferably configured to be removably attachable to a receptacle provided on the bowl. Prefera bly, the solution preparation device further comprises a turbidity sensor provided on the bowl, preferably configured to be removably attachable to a receptacle provided on the bowl.

[0044] Preferably, the turbidity sensor includes an optical sensor integrated in the bottom portion of the bowl, preferably above the magnetic bar.

[0045] Preferably, the solution preparation device further comprises a conductivity sensor provided on the bowl, preferably configured to be removably attachable to a receptacle provided on the bowl or integrated into the bowl material so as to be exposed to the interior space of the bowl.

[0046] Preferably, the solution preparation device further comprises a level sensor provided on the bowl, preferably configured to be removably attachable to a receptacle provided on the bowl or integrated into the bowl material so as to be able to detect a level of the solution in the interior space of the bowl.

[0047] Preferably, at least some of the devices provided on the bowl are configured to communicate data / information with an external controller via a wireless communication protocol, and the solution preparation device further includes an energy source integrated in the bowl, preferably in the form of a (rechargeable) battery, for supplying energy to at least some of the devices provided on the bowl.

[0048] The absence of a physical link or wire between the solution preparation device (bowl) and other components of the system may remove any source of weighing error or handling obstacles in the solution preparation process.

[0049] Preferably, the bowl has an outlet opening provided in the bottom portion, preferably in the center of the bottom portion, preferably below the magnetic bar, the opening configured to be selectively opened to discharge the fluid content from the interior space of the bowl to an external device, preferably by a valve mechanism.

[0050] An advantage of this embodiment is the possibility to easily and safely discharge the solution from the bowl without necessarily handling (i.e. flipping or turning) the device, for example in order to vacuum filter the solution by the bottom of the bowl. Such outlet opening avoids or at least reduces dripping of potentially hazardous solutions or chemicals and also avoids having to use further equipment, for example, a funnel.

[0051] The present application also provides for a solution preparation system comprising a solution preparation device as described herein, a scale on which the solution preparation device is or is to be placed, and one or more dispensers for selectively supplying water and / or a powder and / or a liquid into the interior space of the bowl of the solution preparation device when placed on the scale.

[0052] Preferably, the one or more dispenser / dispensers is / are integrated in a dispenser head arranged in positional association with the scale such that the dispenser head is located above the bowl of the solution preparation device, if the same is placed on the scale.

[0053] The present system allows preparing mixtures starting from powdery compounds, liquid reagents or solvents (both referred to in this context as "liquids" or "liquid compounds") while following predefined procedures or recipes and thus aids in simplifying a laboratory technician's workflow and tasks.

[0054] The present application also addresses difficulties generally encountered in the weighing of powders and liquids with a high precision (i.e. with an error of, for example, at most 0.01 g) while mixing the solution at the same time.

[0055] Simultaneous weighing and stirring is advantageous for the following reasons: In the traditional manual solution preparation process, solid chemical reagents are normally taken from reagent bottles with a spatula and weighed in a weighing dish on a balance or scale. In good practice and manner in laboratory, an excess amount of reagents taken by accident is never returned to the reagent bottle but is thrown away so as to not risk contaminating the original reagent. This causes unnecessary waste, which is particularly undesirable for expensive or hazardous chemicals. Therefore direct weighing at high precision is desirable. The weighed reagent is then transferred to a beaker for dissolution. Solid powder reagents are often fine and stick to the surface of the weighing dish. For complete transfer of the weighed reagent into the beaker, the weighing dish is best rinsed with water, again risking potential spilling and contamination.

[0056] Upon pouring into water for dissolution some chemicals, for example, some types of salts, such as phosphate salts, initially in powder form turn to chunky-sticky blocks due to their hygroscopic aspect. Once this has happened, dissolution of the salt is rather difficult to accomplish. Thus, such compounds are preferably added gradually into stirred water in order to allow the particles to immediately disperse before being able to form agglomerates. Gradual addition also aids in avoiding blocks of such chemicals interfering with the movement of the magnetic stirrer bar, which would also lead to slower dissolution.

[0057] However, stirring at too high speeds generates a centrifugal force in the water leading to salt particles settling at an outer rim of the beaker in a zone where less mixing is taking place, thus slowing down the dissolution process.

[0058] Furthermore, some buffer formulations may contain one or more surfactant(s), entailing the risk of formation of bubbles or foam, particularly at high stirring speed. This can then only be remedied by allowing the solution to sit until the bubbles or foam have disappeared.

[0059] The above problems may be solved by the herein-described system in that weighing of granular and powdery compounds is done in a single weighing and dissolution container (the bowl) while the components of the system are stationary. Further, solid chemical dosing may be done in water for dissolution while stirring.

[0060] Preferably, the solution preparation system further comprises a user interface and a controller, the controller configured to communicate data / information with the user interface and the devices on the bowl, including the magnetic stirrer and the various sensors on the bowl, if provided, and / or the dispensers, if provided, and the scale, and configured to output the data / information to a user and / or external data processing equipment.

[0061] Preferably, the communication of data / information between the controller and at least some of the other devices is configured to be made via a wireless communication protocol.

[0062] Preferably, the controller of the system stores plural sets of instructions for preparing a solution from one or more compounds including the liquid and / or the powder and is configured to present the instructions on the user interface.

[0063] Preferably, the controller is configured to compute equivalent masses of each compound based on a gravimetric analysis. The present device and system are based on a portable bowl fully integrated with an ecosystem of devices and accessories of the system covering the complete laboratory process of solution (buffer) preparation.

[0064] The present system allows preparing mixtures from powdery compounds, liquid reagents and solvents, while following predefined procedures defined in a set of instructions, thereby simplifying a laboratory technician's workflow. The present system can accurately monitor weights, pH and / or temperature or other characteristics or parameters of the preparation (depending on the setup of sensors) without the need of extensive and timeconsuming calibration.

[0065] The present system supports all the steps from the solution (buffer) recipe selection in the form of the sets of instructions to the ready-to-use solution (buffer), if desired even including labelling of the bottle. It can be used in a modular way to perform any one or more, preferably all, of the steps of selection / definition of the recipe, laboratory container (bowl) rinsing, initial filling of the container (bowl), weighing chemical powders, sampling liquid reagents, homogeneous mixing, pH adjustment if required, volume adjustment if required, filtration if required, transfer, and (optionally) labelling.

[0066] The present application thus also provides a method of preparing a solution, preferably a buffer solution, using the solution preparation system as described herein, the method comprising the following steps:

[0067] • selecting a set of instructions for preparing a solution from one or more compounds including the liquid and / or the powder presented on the user interface;

[0068] • arranging the solution preparation device on the scale;

[0069] • prefilling the bowl of the solution preparation device with pure water through one of the dispensers and determining the mass of the water during the dispense by weighing the bowl; and

[0070] • dosing the powder and / or the liquid equivalent to the determined mass of the water through the one or more dispensers, preferably while mixing the solution in the bowl by operating the magnetic stirrer.

[0071] Preferably, the method further comprises automatically adjusting the pH of the solution in the bowl while measuring the pH of the solution through a / the pH sensor provided on the bowl and preferably while mixing the solution in the bowl by operating the magnetic stirrer and / or the method includes a step of filling up to a predetermined volume, potentially in combination with a reduced initial prefilling volume.

[0072] The present application discloses a solution preparation device which can be used in the most general application as a mobile, stand-alone device for the preparation of solutions in a laboratory environment, or in combination and functional integration with other components to form a solution preparation system as set forth below. Even if aspects or features of the solution preparation device are described in conjunction with aspects or components of the solution preparation system, the features related to the solution preparation device are intended to be disclosed independent of the system.

[0073] With reference now to Figure 1, the solution preparation device 1 comprises a portable bowl / container 2 capable of holding a defined volume of a solution in an interior space of the bowl. The volume may typically be in the range of less than 5 liters. As shown in Figure 1, the interior space of the bowl may be defined by a lower interior surface (opposite the open end of the bowl) and one or more sidewalls extending vertically therefrom toward the open end for containing substances within the interior space. The form of the bowl / container is not particularly relevant but may be typically cylindrical (e.g. the sidewall is circular with a constant diameter along its height) with a large open upper end to allow filling of substances into the interior space.

[0074] The bowl / container 2 may be made from glass, plastic material, or metal, or combinations of these materials.

[0075] A lower end of the bowl / container is closed (except where an outlet is provided as described below) and preferably has a central cylindrical recess 3 that is U-shaped (in the diametrical vertical cross-sectional view) as shown schematically in Figure 1 formed in the lower interior surface of the of the interior space. A magnetic bar 4 may be movably, i.e. rotatably provided in the recess 3 in the bottom portion of the interior space of the bowl. For example, the length of the magnetic bar may be less than the width of the recess. A stator 6 is included in a bottom portion of the bowl external to the interior space and surrounding the recess 3. The stator 6 is configured, in conjunction with a circuitry included in the device (not shown), to create a rotating, i.e. circularly moving, magnetic field for rotating the magnetic bar 4 in the recess 3 of the bowl 2 so as to form a magnetic stirrer. The stator 6 and circuitry are included in (e.g. housed within) the bottom portion of the bowl 2. For example, the stator 6 and circuitry may be covered by a separate housing 7 that surrounds the lower part of the bowl 2 and is sealed by itself and / or in conjunction and engagement with the bowl 2 so as to be liquid tight to the outside and to protect the internal elements from water ingress. Thus, the solution preparation device 1 can be washed and dry stored as a unit as regular lab glassware. The housing 7 is preferably made from a non-ferromagnetic material, i.e. plastic or glass.

[0076] The mixing of the solution in the bowl is based on two components: the magnetic bar 4 which is the moving part and the stator 6. In order to save energy and reduce mechanical interference which could lead to noise on the weight measurement or too long stabilization time, the stator is in the form of magnetic coils. Moreover, this arrangement reduces the internal weight and footprint of the device. The working principle of such driving concept for a magnetic stirrer is known and, for example, is described in US 7,040,800 B2.

[0077] As shown in Figure 1, the recess 3 of the lower interior surface of the bowl 2 for receiving the magnetic bar 4 is substantially in plane with the magnetic coils 6a. As such, the axial direction of the magnetic coils 6a of the stator 6 and of the magnetic bar 4 are substantially aligned in the same plane (x-y) in a radial direction of the bowl. The magnetic bar 4 is the rotating element (rotor) composed of a permanently magnetized element covered by a chemically inert material such as a fluoropolymer material (e.g. PTFE).

[0078] The design of the magnetic coils 6a is customized to enable better mixing force (higher couple) while reducing the energy consumed. To be more specific, the integration of the magnetic coils and the magnetic bar in the same device with minimum gaps between the axial driving ends 5 of the coils 6a and those of the magnetic bar 4 arranged so as to face each other has limited the magnetic energy field required. Moreover, the integration of the bowl 2 and the stator 6 reduces the distance between the magnetic coils 6a and the magnetic bar 4. For example, as shown in Figure 1, the inner ends of coils 6a extend centrally toward the recess 3 radially beyond the vertical sidewall(s) of the bowl 2 to reduce the radial distance between the coils 6a and magnetic bar 4. As shown, the outer ends of the coils 6 may also be disposed radially within the sidewall of the bowl 2.

[0079] The specific shape of the central recess 3 with the U-shape in cross section as shown in Figure 1 prevents the magnetic bar to escape or be ejected from the magnetic field area created by the surrounding stator 6. The U-shape of the central recess 3 at the bottom of the bowl also creates a beneficial vortex form in operation that promotes the mixing of the solution in the bowl above the magnetic bar 4 like a mixer.

[0080] Another advantage of this structure is the possibility to discharge to the outside, for example through a filtration device 23, which may optionally be connected to a vacuum pump, the fluid content from the interior space of the bowl 2 by the bottom portion of the bowl via a valve mechanism 28, i.e. a check valve (see Figure 9), selectively opening / closing an outlet integrated in the bottom portion below the magnetic bar 4 as the outside of the bottom of the recess 3 is not occupied by parts of the stator 6.

[0081] The preferred number of magnetic coils 6a that are excited alternately in order to create the rotating magnetic field is six which is optimal in terms of efficiency. Thus, it reduces the angle between each pole to only 60°. But the device 1 can still be operated with only four or five poles (four poles are shown in the Figure 2). The magnetic bar 4 can have two, three or four poles (two poles are shown in the Figure 2) and the present teachings may be compatible with standard rotating magnetic bars. As shown in Figure 2, the stator 6 includes a ring-like magnetic core or iron core 8 with projections 9 projecting radially inward and corresponding to the respective coils 6a wound around the projections 9. The radially inward axial ends of the coils 6a are flush with the radial inward axial ends of the projections 9. The iron core 8 increases the strength of the magnetic field in the electromagnetic coils 6a.

[0082] The benefits of such design of the magnetic stirrer include a reduced vibration during mixing compared to a motor shaft rotating magnet, no wearing parts or maintenance for the drive, a better rotation of the stirrer compared to, for example, the arrangement of US 7,040,800 B2, reduced energy consumption and heating of the solution in the bowl, a portable design with reduced risk of a stirrer bar ejection, and the option to implement filtration and transfer at the bottom of the bowl.

[0083] Figure 3 is a schematic diagram of the basic functional elements of the solution preparation system 10 according to an embodiment of which the solution preparation device 1 as described herein is a component and which provides a range of accessories / devices that allow to perform a seamless lab workflow process for solution (buffer) preparation. The solution preparation system 10 comprises and functionally integrates, in its most general set-up, the solution preparation device 1 as described herein with, a scale 11 on which the solution preparation device 1 can be placed, and one or more dispensers 12 for selectively supplying pure water and / or a powder and / or a liquid into the interior space of the bowl of the solution preparation device 1 (when arranged on the scale 11). Additional accessories / devices may include one or more sensors (e.g. a pH meter 14), a user interface 15 and a controller 16 (not shown in Figure 3 but in Figure 6).

[0084] In the solution preparation system 10 the one or more dispenser / dispensers 12 is / are preferably integrated in a common dispenser head 13 arranged in positional association with the scale 11 such that the dispenser head 13 is located above the bowl 2 of the solution preparation device 1, if the same is placed on the scale 11, so that the water and / or powder and / or liquid can be supplied into the interior space of the bowl 2.

[0085] The dispenser head 13, by including and integrating all the dispensers 12 for powder, liquid and pure water, may be formed so as to ensure a safe enclosure together with the upper opening of the bowl 2. Thus, during the dispensing of the compounds, no powder or liquid is spilled and comes into contact with an operator. The dispenser head 13 can include an engagement portion 13a matched with the upper opening of the bowl (circular in the example of Figure 5) to provide a seal (e.g. against the vertically-extending sidewall(s)). The dispenser head 13 may be supported on a base structure 17 with rails 17a or other mechanical structures that allow the dispenser head 13 to be vertically displaced downward onto the bowl once the bowl 2 is positioned on the scale 11 and below the dispenser head 13 and raised away from the bowl after completion to allow removal of the bowl (see Figure 4 which is a perspective representation of an embodiment of the solution preparation system and a perspective view from below of a variant of the dispenser head).

[0086] Another variant of the dispenser head 13 is shown in Figure 5 which is a perspective view from the side and from below wherein the base structure 17 and support is partially omitted. In this variant a powder dispenser 12 is integrally provided in the dispenser head 13 and includes a stirrer paddle 12b driven by a planetary gear mechanism 12c. Various outlet openings 12a of the powder / liquid dispensers open in the lower surface of the dispenser head 13 so that the water and / or powder and / or liquid can be supplied directly into the interior space of a bowl 2 engaged with the dispenser head 13 (e.g. via the engagement portion 13a).

[0087] Still another variant of the dispenser head 13 is shown in Figure 6 which is a perspective view from the side. The base structure 17 includes a water tank 18 for water (pure water) and a water purification device 19 that can purify the water from the tank 18 and supply it to the respective dispenser 12 as needed. The variant of Figure 6 also shows an example of a user interface 15 and controller 16 separated from the base structure, the function of which will be described later. In this variant, too, the dispensers 12 for the compounds of the solutions to be prepared (pure water, powder, liquid) are integrated in the dispenser head 13 such that the compounds can be supplied into the interior space of the bowl 2 of the solution preparation device 1 that is placed on the scale 11. The dispenser head 13 in this variant may or may not be vertically movable relative to and along the base structure 17.

[0088] The dispenser head 13 may include the elements for a powder delivery function at the respective dispenser 12 wherein the powder reagent is provided in the form of bottles or other exchangeable containers. The elements for implementing the powder delivery function comprise a replaceable bottle / container filled with a powder reagent to be dosed (not shown), a hopper 20 with a connector 20a for receiving the bottle / container and leading to an endless transport screw 21, and a motor 22 arranged to selectively rotate the transport screw to feed the powder from the hopper 20 to the outlet opening 12a of the dispenser 12 and into the bowl (see Figure 7a and Figure 7b).

[0089] The powder reagent bottle may be attached to the threaded connector 20a of the hopper 20 either after its regular commercialized cap is removed or with the cap retained on the bottle. The transport screw 21 can be horizontal as in Figure 7a or vertical as in Figure 7b. Additionally, the connector 20a of the hopper 20 and / or the cap of the reagent bottle can be equipped with a shutter (not shown) to hermetically close and store the powder recipient.

[0090] The bottle can then be used to deliver powder to the dispenser 12 when the transport screw 21 is rotated by operating the motor 22. This motor 22 is preferably a stepper motor that actuates the endless screw 21 on the hopper 20.

[0091] In the variant shown in Figure 7a the hopper 20 may be an integral part of the bottle cap 26 and include the transport screw 21 as well. In this case, the cap 26 including the hopper 20 with the transport screw 21 and the bottle may be selectively attached to a receptacle on the dispenser head 13 and secured by a latch 25 or any other releasable mechanical engagement means, whereupon an end of the transport screw 21 is engaged with and coupled to the shaft of the motor 22 fixed on the dispenser head 13 to transmit the rotational movement to the transport screw 21. When paired with the motor 22, the cap 26 and bottle is positioned above the bowl in order to dispense powder into the bowl. After usage, the bottle with its cap 26 and transport screw 21 is detached from the dispenser head 13 and decoupled from the shaft of the motor 22 by using the latch 25 or the other mechanical engagement means. The bottle can remain with its hopper cap 26 for storage in a regular chemical storage cupboard. The lifetime of the hopper cap 26 is given for the maximum lifetime storage of the reagent and the complete dosing of the bottle.

[0092] The benefits of this variant rely on the possibility of changing the bottle during preparation of a recipe. It makes the dispenser head 13 more compact than having plural bottles connected with specific tubing or being conveyed through a carrousel for instance as in some complex prior art systems.

[0093] The scale 11 is designed to fit the bowl shape and preferably has a range of up to 5 kg with a 0.01 g precision. It is preferably using a piezoelectric sensor. This is based on a strain gauges-based force transducer which is known in the state of the art. The strain gauges are connected on a Wheatstone electronic circuit bridge. When the circuit is power supplied, the output voltage is proportional to the applied force.

[0094] The solution preparation device 1 described herein may further comprise various sensors provided on the bowl 2 to detect properties of the solution being prepared in the bowl. The sensors may be fixedly integrated in the bowl 2, if necessary for the detection so as to be exposed to the interior space of the bowl 2, or may be configured to be removably attachable to a receptacle provided on the bowl 2.

[0095] For example, such sensors may comprise one or more selected from a pH sensor 14, a turbidity sensor, a conductivity sensor and a level sensor for detecting a level of the solution in the interior space of the bowl 2.

[0096] At least some of the devices (sensors / magnetic stirrer 4) provided on the bowl 2 are configured to communicate data / information with an external controller 16 via a wireless communication protocol, and the solution preparation device 1 may further include an energy source 27 integrated in the bowl 2, preferably in the form of a rechargeable battery, for supplying energy to at least some of the devices provided on the bowl 2.

[0097] The wireless communication protocol can be Bluetooth, Bluetooth Low Energy, Zigbee, WIFI or any other P2P or loT communications protocol. The absence of a physical link or wire between the scale 11 and the bowl 2 and / or the bowl 2 and the controller 16 remove any source of weighing error and obstacles for the user.

[0098] The scale 11 may also have connectivity capabilities to communicate with the bowl 2, the user interface 15 and the dispenser head 13 via the controller 16.

[0099] The scale 11 may have additional functionalities to charge the energy source 27 in the bowl 2, for example, through wireless inductive energy. In addition, or as an alternative, standard dedicated wireless chargers can be used which may be beneficial of several bowls are prepared for a system. These chargers as well as the charger of the scale 11 can preferably be based on the commonly known Qi technology.

[0100] As mentioned above the bowl 2 can integrate a pH sensor 14 in order to automate pH adjustment in conjunction with the controller 16 and the dispensers 12 of the system. The pH sensor could be a classic glass electrode known in the state-of-the-art. The sensor can be plugged into the bowl at a connector when used and unplugged for storage in a 1 molar KCI solution. The preferred embodiment includes a pH sensor of the ISFET (ion-sensitive field effect transistor) technology. The ISFETs are easier to maintain than traditional pH sensors. They can be dry stored. This avoids the need to frequently unplug the sensor from the bowl 2. An additional advantage of the solution is the reduction of the calibration frequency. It can be integrated in the bowl 2 in a variety of manners and preferably extends laterally in a horizontal position (see Figure 8). In order to increase the stability of the reference electrode, a multi array electrode could be used.

[0101] The adjustment of the buffer's pH may be done with the help of the liquid dispensing system connected to the liquid dispenser 12 at the dispensing head 13 based on two peristaltic pumps. One pump is connected to an acid and another pump to a base reagent. The reagents are delivered to the bowl 2 through the respective dispenser 12 until a targeted pH value is reached. The adjustment operation is based on the theoretical computation of the required volume of acid or base to be added. A predefined percentage of the theoretical volume is injected at a maximum flow rate. Then a drop-by-drop adjustment is performed based on the value determined by the pH sensor 14. During the complete adjustment operation, the magnetic stirrer 4 is operating and mixing the solution in the bowl 2. The described solution is not limited to acid or base liquid reagent injection. According to an alternative embodiment, a pH adjustment can be based on solid reagent powder dispensed through the above-described powder delivery function.

[0102] As mentioned before, the liquid injection through the respective dispenser 12 in the dispensing head 13 may be performed based on one or more peristaltic pump(s) or may alternatively be implemented by a syringe (that is operated by a motorized dispensing mechanism that is known in the art) or more preferably by a dosing pump connected in a tubing leading to the dispenser.

[0103] As mentioned above, the bowl 2 can integrate a turbidity sensor that may include an optical sensor integrated in the bottom portion of the bowl, preferably above the magnetic bar (not shown). The optical sensor is coupled with a light source in order to check the turbidity of the prepared solution. It is well known in the state of the art to perform non ratio measurement or a radiometric measurement method for high turbidity solutions. The turbidity measurement informs the status of powder dissolution (particle presence scatters light).

[0104] The final turbidity of the solution (buffer) can also be compared with a specified value known in advance to validate the correct buffer preparation. For a turbidity measurement, visible light (650 nm) can be used or infrared (850 nm) to remove the influence of the solution colour. UV-C LED can also be used (255 nm, 265 nm, 280 nm, etc.). Thus, with two photodiodes and LEDs, one can measure both turbidity and absorbance.

[0105] In an alternative variant (not shown) a standalone sensor can also be integrated.

[0106] As mentioned above, the bowl 2 can integrate a conductivity sensor (not shown). The conductivity of the solution is also a physical measurement that can be required or used to validate the correctness of the solution (buffer) preparation. The values can be computed theoretically depending on the recipe. It is well known in the state of the art that a 4-probe sensor can measure the conductivity in the mS / cm range. Preferably, these probes can be inserted into the bowl material (i.e. plastic).

[0107] As mentioned above, the bowl 2 can also integrate a wireless level sensor (not shown). Preferably the level sensor is implemented in the form of an ink capacitive level sensor. This can be impregnated in the bowl material. This sensor can be in the form of Interdigital electrode shape. The energy can be received by RF emitted by a PCB. The solution preparation system 10 may further comprise the user interface 15 and the controller 16, wherein the controller 16 is configured to communicate data / information with the user interface 15 and the devices on the bowl 2, including the magnetic stirrer 4 and the various sensors on the bowl 2 and / or the dispensers 12, as provided, and the scale 11, and is configured to output the data / information to a user and / or external data processing equipment.

[0108] As described above, the communication of data / information between the controller 16 and at least some of the other devices of the system 10 is configured to be made via a wireless communication protocol.

[0109] The controller 16 may further store plural sets of instructions (or recipes) for preparing a solution from one or more compounds including the liquid and / or the powder and is configured to present the instructions for the preparation of the respective recipe on the user interface 15.

[0110] The user interface 15 of the system can rely on any digital graphical user interface such as a tablet, computer, smartphone, attached screen etc. The user interface 15 assists the user through the different steps defined in the prestored sets of instructions (or recipes). It guides the user to handle the right bottle at the right moment (e.g. if the powder delivery function as described above with exchangeable powder bottles is implemented).

[0111] The sets of instructions (or recipes) can be programmed by the user before the start of the preparation process or can be loaded from a data server as predetermined sets and modified if needed by user input through the user interface 15.

[0112] In this connection, the controller 16 is preferably set-up to optimize the stirring conditions in that parameters to operate and control the magnetic stirrer 4 are stored in a memory of the controller 16 and tethered to respective solution (buffer) formulations (recipes). The speed of stirring may, for example, be ramped to its targeted value to perform a smooth and adequate mixing process.

[0113] Based on the controller's configuration, the system 10 can prepare mixtures from powder compounds, liquid reagents and solvents, and pure water while following predefined procedures according to the sets of instructions (or recipes) and can thus simplify the laboratory technician's workflow. It monitors accurately the weight, pH and / or temperature and of other characteristics of the solution depending on the sensor equipment without the need of a heavy calibration.

[0114] For biological applications, the solution (buffer) needs to be filtered. This step removes microbiological contaminants or particles. The filtration device has to have a validated bacterial retention and an excellent chemical compatibility with the solution (buffer).

[0115] As discussed above, the solution (buffer) within the interior space of the bowl 2 can be discharged to an exterior space via an outlet in the bottom portion of the bowl 2. In some aspects, the outlet may contain a valve 28 such that when opened, solution (buffer) can be drained due to gravity without necessarily handling (i.e. flipping or turning) the bowl 2. Alternatively, as shown in Figure 9, the bowl 2 can be easily connected to a vacuum station via the (optional) discharge opening at the bottom portion below the magnetic bar 4 to fill the bottle 29 with the solution (buffer). For example, a valve 28 can be selectively opened / closed to allow the solution (buffer) to be discharged through the outlet of the interior space of the bowl 2. If desired, a sterile filtration with vacuum VAC can be performed on the solution (buffer) as it is being discharged from the bowl 2, for example, by utilizing the vacuum VAC to pull the solution from the interior of the bowl 2 through a filter of the filtration device 23 before being dispensed into the bottle 29. Single use disposable filtration devices for sterile filtration are available from several manufacturers, while all filtration and handling are recommended to be performed in aseptic ways such as in a laminar flow chamber. The present device and system, with direct connection from bowl 2 - filter 23 - bottle 29, allows minimizing exposure of the solution to air, possibly even allowing this step to be performed in a non-sterile environment, i.e. in regular lab (see Figure 9 which is a perspective view of the solution preparation device 1 integrated with a filtration device 23 on a separate support stand 24).

[0116] Using the present solution preparation system, an efficient method of preparing a buffer solution can be implemented that comprises the following basic steps:

[0117] • selecting a set of instructions for preparing a solution from one or more compounds including the liquid and / or the powder presented on the user interface 15;

[0118] • arranging the solution preparation device on the scale 11;

[0119] • prefilling the bowl 2 of the solution preparation device 1 with pure water through one of the dispensers 12 and determining the mass of the water during the dispense by weighing the bowl; and dosing the powder and / or the liquid equivalent to the determined mass of the water through the one or more dispensers 12, preferably while mixing the solution in the bowl 2 by operating the magnetic stirrer 4.

[0120] The method may further comprise automatically adjusting the pH of the solution in the bowl 2 while measuring the pH of the solution through a / the pH sensor 14 provided on the bowl 2 and preferably while mixing the solution in the bowl 2 by operating the magnetic stirrer 4.

[0121] In a more complete approach, the method of preparation of a buffer using the present system may comprise the following steps / actions and involves the associated components of the system:

[0122] (A) the user selects the recipe on the user interface 15 (component of the system: user interface 15);

[0123] (B) the user adjusts the recipe parameters (i.e. concentration and volume) (component of the system: user interface 15);

[0124] (C) the system computes the equivalent mass of each compound thanks to a gravimetric analysis (component of the system: controller 16);

[0125] (D) the user (or an automated manipulator or robot) positions the solution preparation device (bowl 2) on the scale 11 under the dispenser head 13 (component of the system: solution preparation devicel, bowl 2, scale 11);

[0126] (E) the system prefills 80% of the desired volume in the bowl 2 with pure water, during the dispense the scale 11 is weighing the water (component of the system: solution preparation device (bowl), scale, dispenser for pure water);

[0127] (F) the user following the user interface's instructions engages a (first) powder reagent bottle (component of the system: user interface 15, controller 16, dispenser 12);

[0128] (G) the system starts dosing the powder to the desired weight into the bowl 2 while the weight is measured by the scale 11 (component of the system: controller 16, dispenser 12, scale 11);

[0129] (H) the bowl 2 ensures the solution's homogeneity while mixing (component of the system: solution preparation device (bowl 2), controller 16);

[0130] (J) the user following the user interface's instructions engages a (first) liquid reagent bottle in the liquid dispenser 12 (component of the system: user interface 15, controller 16, dispenser 12);

[0131] (K) the system starts dosing the liquid to the desired weight into the bowl 2 while the weight is measured by the scale 11 (component of the system: controller 16, dispenser 12, scale 11); (L) the bowl 2 ensures the solution's homogeneity while mixing (component of the system: solution preparation device (bowl 2), controller 16);

[0132] (M) the system adjusts the pH of the solution while the solution preparation device (bowl 2) is transmitting the pH of the solution and mixes the solution - the theoretical volume is known by the system that adjusts drop by drop acid or base (component of the system: solution preparation device (bowl 2), controller 16, dispenser 12);

[0133] (N) the user adjusts the final volume with a water wash bottle (optional manual process or via the dispenser 12 for pure water);

[0134] (O) optionally, the user may filter the solution through a 0.22 pm filter station to a sterile bottle (optional process using the solution preparation device (bowl 2) and an external filtration device);

[0135] (P) optionally, the system may print the label to be sticked by the user to the sterile transport container, programs a RFID tag or an e-ink label on the container (optional process using the controller and external equipment).

[0136] The labelling of the solution (buffer) in the final transport container can be performed in several ways by:

[0137] • a sticky label printed by a wireless printer communicating with the user interface 15 and controller 16 (for example including a QR Code or bar code for additional information on its composition);

[0138] • an RFID tag provided / fixed on the bowl 2 and programmed through a suitable interface communicating with the user interface 15 and controller 16;

[0139] • an e-paper display provided / attached on the bowl 2 using electronic ink (e-ink) that can be programmed / written through a suitable interface communicating with the user interface 15 and controller 16.

[0140] The e-paper display is preferred as it has a number of advantages including no power consumption as the energy is only when writing the data to the display, the fact that data including all the reglementary and safety pictograms can be displayed and remains readable directly without any external device, and the screen is flexible and can follow / adapt the shape of the transport container (i.e. can be curved when the container is cylindrical). Reference sign list

[0141] 1 solution preparation device

[0142] 2 bowl / container

[0143] 3 recess

[0144] 4 magnetic bar

[0145] 5 driving end of coil

[0146] 6 stator

[0147] 6a coils

[0148] 7 housing

[0149] 8 iron core

[0150] 9 projections of iron core

[0151] 10 solution preparation system

[0152] 11 scale

[0153] 12 dispenser(s)

[0154] 12a outlet opening of dispenser

[0155] 13 dispenser head

[0156] 13a engagement portion

[0157] 14 pH sensor

[0158] 15 user interface

[0159] 16 controller

[0160] 17 base structure

[0161] 17a rail(s)

[0162] 18 water tank

[0163] 19 water purification device

[0164] 20 hopper

[0165] 20a connector for receiving a bottle

[0166] 21 transport screw

[0167] 22 motor

[0168] 23 filtration device

[0169] 24 support stand

[0170] 25 latch

[0171] 26 bottle cap

[0172] 27 energy source

[0173] 28 valve

[0174] 29 bottle

[0175] VAC vacuum

Claims

Claims1. A solution preparation device (1) comprising: a portable bowl / container (2) capable of holding a defined volume of a solution in an interior space of the bowl (2), wherein the interior space of the bowl (2) is configured to receive a magnetic bar (4); and a stator (6) included in a bottom portion of the bowl (2) external to the interior space of the bowl (2) and configured, in conjunction with a circuitry, to create a rotating magnetic field for rotating the magnetic bar (4) in the bowl (2) so as to form a magnetic stirrer.

2. The solution preparation device (1) according to claim 1, further comprising the magnetic bar (4), preferably wherein the interior space is defined by a lower interior surface having a recess (3) configured to receive the magnetic bar (4) therein, preferably wherein the recess (3) is substantially in plane with the stator (6), preferably wherein the stator (6) extends centrally toward the recess (3) beyond at least one sidewall of the interior space.

3. The solution preparation device (1) according to claim 1 or 2, further comprising a pH sensor (14) provided on the bowl (2), preferably configured to be removably attachable to a receptacle provided on the bowl (2).

4. The solution preparation device (1) according to any one of claims 1 to 3, further comprising a turbidity sensor provided on the bowl (2), preferably configured to be removably attachable to a receptacle provided on the bowl (2), preferably wherein the turbidity sensor includes an optical sensor integrated in the bottom portion of the bowl (2), preferably above the magnetic bar (4).

5. The solution preparation device (1) according to any one of claims 1 to 4, further comprising a conductivity sensor provided on the bowl (2), preferably configured to be removably attachable to a receptacle provided on the bowl (2) or integrated into the bowl material so as to be exposed to the interior space of the bowl (2).

6. The solution preparation device (1) according to any one of claims 1 to 5, further comprising a liquid level sensor provided on the bowl (2), preferably configured to be removably attachable to a receptacle provided on the bowl (2) or integrated intothe bowl material so as to be able to detect a level of the solution in the interior space of the bowl (2).

7. The solution preparation device (1) according to any one of claims 1 to 6, wherein at least some of the devices provided on the bowl (2) are configured to communicate data / information with an external controller (16) via a wireless communication protocol, and the solution preparation device (1) further including an energy source (27) integrated in the bowl (2), preferably in the form of a rechargeable battery, for supplying energy to at least some of the devices provided on the bowl (2).

8. The solution preparation device (1) according to any one of claims 1 to 7, wherein the bowl / container (2) has an outlet opening provided in the bottom portion, preferably below the magnetic bar (4), the opening configured to be selectively opened to discharge the fluid content from the interior space of the bowl (2) to the outside, preferably to an external device, preferably by a valve mechanism (28).

9. A solution preparation system (10) comprising: a solution preparation device (1) according to any one of claims 1 to 8; a scale (11) on which the solution preparation device is placed; and one or more dispensers (12) for selectively supplying water and / or a powder and / or a liquid into the interior space of the bowl (2) of the solution preparation device (1) when placed on the scale (11).

10. The solution preparation system (10) according to claim 9, wherein the one or more dispenser / dispensers (12) is / are integrated in a dispenser head (13) arranged in positional association with the scale (11) such that the dispenser head (13) is located above the bowl (2) of the solution preparation device (1), if the same is placed on the scale (11).

11. The solution preparation system (10) according to claim 9 or 10, the solution preparation system (10) further comprising a user interface (15) and a controller (16), the controller (16) configured to communicate data / information with the user interface (15) and the devices on the bowl (2), including the magnetic stirrer and the various sensors (14) on the bowl (2), if provided, and / or the dispensers (12), if provided, and the scale (11), and configured to output the data / information to a user and / or external data processing equipment, wherein the communication ofdata / information between the controller (16) and at least some of the other devices is configured to be made via a wireless communication protocol.

12. The solution preparation system (10) according to claim 11, wherein the controller (16) stores plural sets of instructions for preparing a solution from one or more compounds including the liquid and / or the powder and is configured to present the instructions on the user interface (15).

13. The solution preparation system (10) according to claim 12, wherein the controller (16) is configured to compute equivalent masses of each compound based on a gravimetric analysis.

14. A method of preparing a solution, preferably a buffer solution, using the solution preparation system according to claim 12 or 13, the method comprising: selecting a set of instructions for preparing a solution from one or more compounds including the liquid and / or the powder presented on the user interface (15); arranging the solution preparation device (1) on the scale (11); prefilling the bowl (2) of the solution preparation device (1) with pure water through one of the dispensers (12) and determining the mass of the water while dispensing by weighing the bowl (2); and dosing the powder and / or the liquid equivalent to the determined mass of the water through the one or more dispensers (12), preferably while mixing the solution in the bowl (2) by operating the magnetic stirrer.

15. The method according to claim 14, further comprising automatically adjusting the pH of the solution in the bowl (2) while measuring the pH of the solution through a / the pH sensor (14) provided on the bowl (2) and preferably while mixing the solution in the bowl (2) by operating the magnetic stirrer and / or a step of filling up to a predetermined volume, potentially in combination with a reduced initial prefilling volume.

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