WO2018154503A1

WO2018154503A1 - Mixing apparatus and method

Info

Publication number: WO2018154503A1
Application number: PCT/IB2018/051141
Authority: WO
Inventors: Venugopal Tammishetti; Arjun Kumar PUKKELLA; Raviraju VYSYARAJU; Sivakumar Subramanian; Beena Rai
Original assignee: Tata Consultancy Services Limited
Priority date: 2017-02-23
Filing date: 2018-02-23
Publication date: 2018-08-30

Abstract

A mixing apparatus for mixing ingredients is provided. The mixing apparatus includes a container, an impeller assembly, and one or more protruding attachments. The container holds the ingredients. The impeller assembly is rotatably positioned in the container for stirring the ingredients. The motion of the ingredients forms a vortex in the container. The one or more protruding attachments is supported within the container by a support mechanism and positioned to vertically move upwards and downwards direction within the container. The protruding attachment(s) redirects at least a portion of the plurality of ingredients between a top portion of the vortex and a bottom portion of the vortex.

Description

MIXING APPARATUS AND METHOD

CROSS REFERENCE TO RELATED APPLICATIONS AND PRIORITY

[001] The present application claims priority to Indian Application (Title: Mixing apparatus and method), Application No. 201721006575, filed on February 23, 2017. The entire contents of the aforementioned application are incorporated herein by reference.

TECHNICAL FIELD

[002] The embodiments herein generally relate to mixing of ingredients, and, more particularly, to a mixing apparatus and method for homogenous mixing of ingredients in a power-efficient manner.

BACKGROUND

[003] Modern researches are focused on beneficiation methods involved in industrial processes. Beneficiation methods, for instance, slurry beneficiation involve mineral processing in which gangue minerals are separated from ore to produce high grade material. Currently, various methods are employed for beneficiation of grade slurry/ores. These methods involve treatment of raw slurry in apparatuses so as to separate high grade product from waste stream.

[004] During the beneficiation process, various ingredients are mixed together. For instance, slurry is treated with reagents. Typically, beneficiation apparatuses include mixers that facilitate proper mixing of the ingredients. In particular, a mixer's function is to mix different ingredients, for example, solid-liquid ingredients or liquid-gaseous ingredients, and prepare a uniform mix.

[005] Currently various mixers are being employed for agitation of ingredients in industrial processes. However, with these mixers, it is challenging to effectively mix the ingredients so as to achieve uniform distribution of materials. Some of the improved systems include vertical baffling systems that increase the turbulence, and hence the mixing is improved, however, such systems consume high power, and thus are not energy-efficient. Moreover, since the baffled mixing systems increases turbulence, said systems also induces more shear which is not suitable for soft materials, such as bio-algae, because such high turbulence may rupture the cell tissues of soft materials.

SUMMARY [006] The following presents a simplified summary of some embodiments of the disclosure in order to provide a basic understanding of the embodiments. This summary is not an extensive overview of the embodiments. It is not intended to identify key/critical elements of the embodiments or to delineate the scope of the embodiments. Its sole purpose is to present some embodiments in a simplified form as a prelude to the more detailed description that is presented below.

[007] In view of the foregoing, in one embodiment, a mixing apparatus for mixing various ingredients is provided. The mixing apparatus includes a container, an impeller assembly, and one or more protruding attachments. The container holds a plurality of ingredients to be mixed. The impeller assembly is electrically connected to a motor and is rotatably positioned in the container for stirring the plurality of ingredients. The motion of the plurality of ingredients due to stirring forms a vortex in the container. The impeller assembly includes a vertical central elongated rod positioned along a vertical axis of the container, and a plurality of blades aligned radially outwards from the vertical central elongated rod. The one or more protruding attachments are removably supported within the container by a support mechanism. Further, the one or more protruding attachments are positioned to move vertically upward and downward directions within the container, and redirects at least a portion of the plurality of ingredients between a top portion of the vortex and a bottom portion of the vortex.

[008] In another embodiment, a method for mixing is provided. The method includes introducing a mixture of a plurality of ingredients in a mixing apparatus. The mixing apparatus includes a container to hold the plurality of ingredients to be mixed, an impeller assembly electrically connected to a motor and rotatably positioned in the container, and one or more protruding attachments removably supported within the container by a support mechanism, and further positioned to move in vertically upward and downward directions within the container. Further, the method includes stirring, by the impeller assembly, the mixture of the plurality of ingredients in the container. Motion of the plurality of ingredients due to stirring forms a vortex in the container. Furthermore, the method includes redirecting, by the one or more protruding attachments, at least a portion of the plurality of ingredients between a top portion of the vortex and a bottom portion of the vortex. Redirecting the at least a portion of the plurality of ingredients facilitates in mixing of the plurality of ingredients. [009] Herein, when the mixture (of the plurality of ingredients) is agitated using the impeller, the vortex formed in the container has a high concentration of denser particles at the bottom portion of the vortex (or the container) and a relatively lower concentration at the top portion. The one or more protruding attachment configured towards the top portion of the vortex (or the container) facilitates in directing the less denser particles of the mixture (for example, slurry) towards the bottom from the top portion of the container, thereby effectively enhancing the mixing. In another example scenario, where the mixture is a liquid-gas mixture or liquid-neutral buoyant particle phase, the scenario would be other way round. For instance, in a liquid-gas mixture, the mixture contains higher amount of / high concentration of gas in the top portion of mixture, and said gas is directed towards the bottom portion of the container, where it is mixed with the lean stream (meaning thereby, lesser concentrated gas dispersed in liquid). Moreover, the one or more protruding attachment offers minimal resistance to the mixture, thereby facilitating effective homogenization of the ingredients, reducing energy consumption and improving energy efficiency of the mixing apparatus.

BRIEF DESCRIPTION OF THE FIGURES

[0010] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and modules.

[0011] FIGS. 1A, IB and 1C illustrate a convention mixing apparatus, vortex formed during mixing in the convention mixing apparatus, and particle distribution in the convention mixing apparatus.

[0012] FIGS. ID, IE and IF illustrate another convention mixing apparatus, vortex formed during mixing in the convention mixing apparatus, and particle distribution in the convention mixing apparatus.

[0013] FIGS. 2A and 2B represent graphical representation of particle size distribution for conventional mixing apparatuses of FIGS. lA and ID.

[0014] FIGS. 3A illustrate a mixing apparatus in accordance with an example embodiment.

[0015] FIGS. 3B illustrate a mixing apparatus in accordance with another example embodiment.

[0016] FIGS. 3C illustrate a mixing apparatus in accordance with yet another example embodiment.

[0017] FIG. 4A illustrate particle distribution in a mixing apparatus, in accordance with an example embodiment of present disclosure. [0018] FIG. 4B illustrate formation of vortex in the mixing apparatus, in accordance with an example embodiment of present disclosure.

[0019] FIG. 5 represents graphical representation of particle size distribution for the mixing apparatus of FIG. 3 A.

[0020] FIG. 6 illustrates a flow-diagram of a method for mixing, in accordance with an example embodiment.

DETAILED DESCRIPTION

[0021] Some embodiments of this invention, illustrating all its features, will now be discussed in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.

[0022] It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any apparatus and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, the preferred apparatus and methods are now described.

[0023] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0024] Typically, in industrial applications, huge amounts of ingredients are brought to laboratory where the sample is homogenized to make it representative, and further for performing experiments. Herein, the term 'ingredients' refer to various materials that can be mixed for homogenization of different phases for instance, solid particles in solid-liquid systems. Accordingly, the terms 'ingredients', 'materials' and 'phases' shall be used interchangeably throughout the description.

[0025] The process of mixing to achieve uniform distribution of materials is utmost important in process industries for sampling as well as processing. Generally, mixing of ingredients such as liquids or solid-liquids or gas-liquid phases is achieved by mixing said ingredients in a container by means of an impeller.

[0026] Referring to FIG. 1A, a conventional mixing apparatus 110 is illustrated. The conventional mixing apparatus 110 includes an impeller 112 for mixing ingredients in a mixing tank, for instance a mixing tank 114. As a result of the mixing action of the impeller, a vortex 116 is formed in the mixture, as illustrated with reference to FIG. IB. During mixing using the conventional mixing apparatus 110, different phases such as solid particles in solid-liquid systems (i.e., slurries) get segregated due to high specific gravity of solids, as illustrated in FIG. 1C. Said particle segregation can be avoided by proper mixing of the slurry. However, a challenge with existing mixing apparatus is to achieve uniform mixing of different phases with less power input. Energy consumption is high in homogenizing slurries as slurries need high agitations to suspend all the particles.

[0027] Another type of existing mixing apparatus 130 is illustrated with reference to FIG. ID. The mixing apparatus 130 includes vertical baffles, for example baffles 132, 134, 136, 138, along the walls of a container 130 in which slurry is filled for agitation and proper mixing of ingredients. As is illustrated in FIG. IE, as result of said agitation no vortex is formed in the mixture. Such baffled mixing apparatus increases load on the impeller, thereby mandating need for higher power systems so as achieve enhanced agitation speeds. In such mixing apparatus, baffles are provided to induce turbulence in the mixture, however, the baffles offer huge resistance to the flow, and thus to the impeller, thereby increasing power requirements for the mixing apparatus 130. Additionally, long baffles increases the turbulence but slows down the impeller speed due to which homogenous distribution may not be achieved, as is illustrated in FIG. IF. An example scenario of utilizing conventional mixing apparatus for mixing, and resultant particle size distribution in the mixture are described further with reference to FIGS. 2 A and 2B.

[0028] FIGS. 2A and 2B represent graphical representation of particle size distribution for conventional mixing apparatuses. For example, FIG. 2A illustrates graphical representation of particle size distribution achieved by mixing ingredients of a mixture by a conventional mixing apparatus (without baffles) 110 illustrated in FIG. 1A. FIG. 2B illustrates graphical representation of particle size distribution achieved by mixing ingredients of said mixture by a conventional mixing apparatus 130 (with multiple long baffles) illustrated in FIG. IB.

[0029] For describing the scenarios, the mixture is considered to include Silica slurry, wherein slurry pulp density is 8 grams of solids/ 100 ml of slurry. Also, different fractions of silica are considered for which the particle sizes are known. Said fractions of silica are mixed together which resulted in cumulative mass mean diameter of 80 microns. [0030] In case of a conventional mixing apparatus (without baffles) 110, 50 Liters of slurry is taken in a container of the conventional mixing apparatus (without baffles) and agitated by increasing the impeller rotational speed using a regulator (controller) such that the slurry forms as vortex. The regulator knob position of said conventional system is fixed so as to maintain same power input to the impeller. Impeller rpm is determined to be 152. After mixing time of 15 minutes, two samples are collected, one from the top portion of the slurry and the other from the bottom of the tank using a tap. The tap is about 3 centimeters height from the bottom of the tank. Mean particle sizes are found to be 57.24 and 51.84 microns for the samples collected from bottom portion and top portions, respectively of the vortex. Due to settling of bigger particles at the bottom of the container, the mean sizes are determined lower than the actual mean size of the silica mixture taken. A graph illustrating particle size distribution for top portion and bottom portions of conventional mixing system without baffles is illustrated in FIG. 2A.

[0031] In another example scenario of the conventional mixing apparatus with long baffles (explained with reference to FIGS. 1D-1F), container with four vertical baffles is filled with silica slurry. The mixture is agitated without changing the power input (i.e., the regulator position is same as in case of the mixing system without baffles where vortex was formed). Impeller speed is dropped to 52 rpm due to resistance of baffles, and no vortex formation is observed, however, turbulence may be seen. Two samples were collected, one from the top and the other from the bottom of the tank and particle sizes were analyzed. Mean particle sizes were found to be 23.87 and 26.54 microns for samples collected from top portion and bottom portion of the container, respectively. It was observed that there is increase in bigger particle settling in the container compared to the system of agitation without baffles due to which mean particle sizes of both sample are much lesser than 80 microns which was actual mean particle size. A graph illustrating particle size distribution for top portion and bottom portions of conventional mixing system with four baffles is illustrated in FIG. 2B.

[0032] Impeller speed and mean particle sizes for conventional mixing/agitation apparatuses, and pulp densities of the samples for conventional mixing apparatus are listed in Tables 1 and 2, respectively. As illustrated in Table 1, D10, D50 and D90 are cumulative 10%, 50% and 90% point of diameter. Herein, in FIGS. 2A, 2B and later in FIG. 5, average sizes corresponding to the cumulative weight % of 10, 50 and 90 are D10, D50 and D90, respectively (D10, D50 and D90 are standard notation of particle sizes corresponding to cumulative weight % of 10, 50 and 90, respectively).

Table 1 : Impeller speed and mean particle sizes for conventional mixing apparatus Mixing Sample Impeller Mean size D10 D50 D90 Apparatus RPM (microns) (microns) (microns) (microns)

For Constant

Power Input

Without Top 152 51.84 2.38 34.04 128.18

Baffles Bottom 57.24 3.30 37.95 138.60

Top 52 23.87 0.91 13.87 45.04

With Baffles Bottom 26.54 1.40 21.26 56.94

Table 2: Pulp densities of the samples for conventional agitation systems

[0033] In yet another example scenario of a conventional mixing apparatus, multiple static baffles are placed at varying heights and are displaced from each other. Said multiple baffles are configured or attached along the wall of the container vertically such that there is no gap between the container wall and the baffles. The baffles completely submerged in the mixture (for example, slurry) for facilitating mixing of the ingredients of the mixture. However, such multiple baffles interact perpendicularly with a circular stream formed due to the vortex, thereby destructively obstructing the vortex.

[0034] Various embodiments disclosed herein provide mixing apparatus and method for mixing in a manner that overcomes limitations of existing methods and apparatus used for mixing ingredients. For example, the embodiments disclose a mixing apparatus that includes one or more protruding attachments extending from the wall of the container holding the ingredients to be mixed. The protruding attachment is configured so as to assume a position at a top portion of a vortex formed due to motion of ingredients in the container and direct the flow towards a bottom portion of the container preferably, center of the vortex, thereby leading to effective mixing. In addition, the protruding attachment(s) are relatively very small in size as compared to the long conventional baffles, and thus offers minimal resistance to the flow due to a small size thereof compared to a regular baffle system, thereby providing a power and energy efficient system. As will be understood later, the protruding attachment(s) may be special kind of baffles that are smaller than typical baffles, and are capable of controlling the vortex formed in the mixture.

[0035] Unlike the conventional baffles that are typically submerged in the mixture, the protruding attachments disclosed herein are removably placed in the mixture such that the position of the protruding attachment overlaps (or coincides) with the top portion of the vortex. Also, unlike conventional baffles that are fixedly attached to mixing apparatus, the disclosed protruding attachments are movably placed in the mixture. The movement of the protruding attachments facilitates positioning thereof at a surface of the vortex. Additionally, since the disclosed protruding attachments are substantially small in size as compared to the conventional baffles, said protruding attachments do not obstruct the vortex, and thus unlike convention mixing apparatus, the disclosed mixing apparatus avoids a complete destruction of the vortex.

[0036] Due to the aforementioned features of the protruding attachments configured in the mixture, the disclosed mixing apparatus offers relatively very less resistance (as compared to conventional mixing apparatus) to the mixture with effective homogenization. The disclosed apparatus can also be used for better heat and mass transfer in the multiphase systems containing solid-fluid or fluid-fluid mixtures, as mixing is effective.

[0037] While aspects of described apparatus and method for mixing can be implemented in any number of different systems, utility environments, and/or configurations, the embodiments are described in the context of the following exemplary system(s).

[0038] FIG. 3A illustrates a mixing apparatus 302, in accordance with an example embodiment. The mixing apparatus 302 can be utilized for mixing of ingredients such as solid-liquid ingredients, liquid-gas ingredients, and so on. The mixing apparatus 302 is shown to include a container 310, an impeller assembly 320, and a protruding attachment 330.

[0039] The container 310 is capable of holding a plurality of ingredients to be mixed. For instance, the container 310 may hold slurry and a reagent for mixing and treating. During the mixing of the ingredients in the container to form a mixture, the mixture forms a vortex. An example of the vortex formed by mixing the ingredients is further illustrated and described with reference to FIG. 4B. In the present embodiment, the container 310 is shown to have a conical shape. It will however be understood that the container 310 may be of any other shape that can facilitate in mixing of the ingredients, and forms a vortex during said mixing. For instance, the container can be of cylindrical shape. A cylindrical shaped container 316 for a mixing apparatus 360 is illustrated with reference to FIG. 3B. The mixing apparatus 360 is similar to the mixing apparatus 302 (FIG. 3A) and, with only difference in the shape of the container utilized for holding the ingredients. The remaining components of the mixing apparatus 360 are similar to the corresponding components of the mixing apparatus 302. For this reason, the numbering given to the components of the mixing apparatus 360 is same as the numbering given to the components of the mixing apparatus 302. Hence, for the brevity of description, all the remaining components of the mixing apparatus 360 will not be explained herein.

[0040] The vortex, for example, a vortex 240 is formed during stirring or mixing of the ingredients in the container 310. Herein, the impeller assembly 320 is rotatably positioned in the container 310 for stirring the plurality of ingredients. In an embodiment, the impeller assembly 320 is electrically connected to a motor 326 for stirring the ingredients. The impeller assembly 320 includes a vertical central elongated rod 322 positioned along a vertical axis of the container, and a plurality of blades 324 aligned radially outwards from the vertical central elongated rod 322. Herein, it will be noted that the impeller assembly 320 may assume any configuration of the impellers known in the art without limiting the teachings of various embodiments of the present disclosure. For instance, the impeller assembly 320 may be radial flow impeller, mixed flow impeller, axial impeller and peripheral impeller, and so on. Additionally, the impeller assembly may include any configuration and number of blades known in art. It will be understood that in various embodiments, the type of impeller assembly may be selected based on the application employing the mixing apparatus 302. Also, based on the design of the impeller and the application of the mixing apparatus 302, the angle between the vertical central elongated rod 322 and the blades 324 can vary. It will be noted herein that in said embodiments, since the disclosed apparatus does not include large vertical baffles, the resistance to the flow of the mixture in the container is relatively very less.

[0041] The motion of the ingredients due to stirring forms a vortex (marked as 340) in the container 310. A bottom portion (marked as 344) of the vortex 340 may be formed towards the base on the container 310, while a top portion (marked as 342) of the vortex 340 may be formed towards the top portion of the container 310. During the mixing process, for example during mixing of solid particles in solid-liquid systems (i.e., slurries), due to high specific gravity of solids, different phases may be segregated, and the solid particle concentration may tend to be higher at the bottom of the container 310 and lower towards a top portion of the container 310. The protruding attachment 330 may be supported in the container by means of a support mechanism, and, redirects at least a portion of the plurality of ingredients from a top portion 342 of the vortex 340 towards a bottom portion 344 of the vortex 340, thereby homogenizing the concentration of phases in the mixture. Herein, the protruding attachment(s) redirects the flow of ingredients in the mixing apparatus, and hence is able to control the formation of the vortex. Accordingly, in the present disclosure, the vortex formed is a controlled vortex.

[0042] Herein, it should be noted that in the present description, the one or more protruding attachments are described to include a single attachment configured at a location that may interact with the top portion of the vortex. However, in alternate embodiments, the number of protruding attachments in the mixing apparatus 302 may be more than one. For instance, in an example embodiment, the container 310 may include two protruding attachments configured in a diametrically opposite direction on the wall of the container such that one of the protruding attachments is at a level closer to the bottom portion and another protruding attachment is configured closer to the top portion 342 of the vortex 340 or the container 310. For instance, the mixing apparatus 302 is shown to include an additional protruding attachment 332 configured towards the bottom portion of the vortex 340 or the container 310. Such an arrangement of the two protruding attachments (positioned in a diametrically opposite positions on upper and lower portions of the vortex and/or the container) enhances the mixing of the mixture since the upper attachment redirects the flow towards the bottom portion, and the lower attachment lifts the concentrated stream or mixture at the bottom portion, thereby enhancing the mixing of the ingredients in the mixing apparatus.

[0043] In an embodiment, the protruding attachments, for example, the protruding attachments 330, 322 may be positioned to move vertically upwards and/or downwards with respect to the level of mixture in the container 310. The vertical movement of the protruding attachment 330 facilitates in adjusting the location of the protruding attachment in accordance with the size of the vortex 340 and/or according to a level of ingredients in the container 310. For instance, in case the container 310 is only partially filled or less than half filled, the protruding attachment 330 is positioned towards a middle portion of the container 310 so that the top portion of the vortex 340 can coincide with the protruding attachment 330, and the protruding attachment 330 can redirect at least a portion of the ingredients from the top portion 342 of the vortex 340 towards a bottom portion 344 of the vortex 340. Also, the protruding attachment 332 may be positioned towards the bottom portion of the container 310 so that the bottom portion 344 of the vortex 340 can coincide with the protruding attachment 332, and the protruding attachment 332 can redirect at least a portion of the ingredients from the bottom portion 332 of the vortex 340 towards the top portion 342 of the vortex 340.

[0044] In an embodiment, in order to facilitate vertical movement of the protruding attachment 330 with respect to the level of mixture (or ingredients) and/or the vortex in the container 310, the mixing apparatus 302 may include a support mechanism for holding the protruding attachment. Additionally, the support mechanism may enable vertical movement of the protruding attachment with respect to the vortex. In an embodiment, the support mechanism may include one or more vertical groves, for example vertical groves 312a, 312b configured in the wall of the container 310. The vertical grove(s), for example a vertical grove(s) 312a, 312b, may allow vertical movement of the protruding attachment (for example, the protruding attachment 330, 332 respectively) therein so that the position or level of the protruding attachment may be fixed with respect to the level of the mixture) or level of the vortex. Similarly, in order to facilitate vertical movement of the protruding attachment 332, the mixing apparatus 302 may include a grove, for example a grove 314 for holding the protruding attachment 332. It will be noted that for a given operation, the position of the protruding attachment may be fixed with respect to the corresponding grove.

[0045] In an embodiment, the position of the protruding attachment in the vertical grove may be fixed by examining the level of the mixture in the container 310. In an embodiment, the protruding attachment 330 may be hingedly attached to the vertical grove 312 by means of a hinge mechanism. The hinge mechanism enables the protruding attachment 330 to move vertically along the groove 312 and can position the protruding attachment 330 at an angle such that the protruding attachment 330 directs the top portion of the slurry towards the bottom portion 344 of the vortex 340.

[0046] In another embodiment, the support mechanism may include one or more clamp assemblies, for example, clamp assemblies 318a, 318b configured external to the container and capable of extending (or movably configuring) the protruding attachment(s) in the container. The clamp assemblies 318a, 318b facilitates in the vertical movement of the protruding attachment(s) 330, 332 with respect to the level of mixture (or ingredients) and/or the vortex in the container 310. An example of a mixing apparatus having the clamp assembly is illustrated in FIG. 3C.

[0047] Referring to FIG. 3C, a mixing apparatus 370 is illustrated. The mixing apparatus 370 is similar to the mixing apparatus 302 (FIG. 3A) and the mixing apparatus 360 (FIG. 3B), with only difference being in the support mechanism utilized for holding the protruding attachments in said apparatuses. FIG. 3C is included herein to describe the mixing apparatus having the clamp assembly for holding the protruding attachment. Since remaining components of the mixing apparatus 370 are similar to the corresponding components of the mixing apparatus 302 and/or 360, the numbering given to the components of the mixing apparatus 370 is same as the numbering given to the components of the mixing apparatus 302 and/or 360. Hence, for the brevity of description, all the remaining components of the mixing apparatus 302 and/or 360 will not be explained herein. An important advantage of configuring the support mechanism is that the support mechanism facilitates in removably attaching the protruding attachment with the container, and this makes the cleaning of the apparatus and the protruding attachments convenient. For instance, for the purpose of cleaning the mixing apparatus, the protruding attachment(s) can be conveniently removed from the support mechanism, and cleaned, and thereafter resued.

[0048] Referring collectively now to FIGS. 3 A, 3B and 3C, an outflow port 350 may be configured at the bottom portion of the container 310/316. The outflow port is configured to discharge the treated mixture, for instance slurry. Herein, the outflow port 350 may include a tap.

[0049] As described previously, in the disclosed design of the mixing apparatus 302/360/ 370, the protruding attachment 330 positioned at the top portion of the vortex 340, respectively directs the flow towards the bottom of the container preferably, towards the center of the vortex; and the protruding attachment 332 positioned at the bottom portion or the middle portion of the vortex 240 directs the flow towards the top portion of the vortex and/or the container, thus leading to effective mixing of the ingredients. An example illustrating formation of vortex and mixing of ingredients by the disclosed apparatus are described further with reference to FIGS. 4A-4B.

[0050] Referring now to FIGS. 4 A and 4B an example scenario indicating mixing obtained by mixing ingredients by the disclosed apparatus, for example, the apparatus 302 is described. In case of the mixing apparatus (for example the mixing apparatus 302) with protruding attachment, silica slurry is taken in a container, for instance the container 310 (of FIG. 3 A) having a protruding attachment (for instance, the protruding attachment 312 of FIG. 3A). Slurry formed vortex 402, as illustrated in FIGS. 4 A and 4B, and the protruding attachment are adjusted such that the slurry from the top portion of the vortex 402 is directed to the bottom portion of the vortex 402, and vice-versa. The impeller rotational speed is determined to be 115 rpm. The determined impeller speed is almost double the speed with four baffled system and 2/3 times the un-baffled apparatus (described previously with reference to tables 1 and 2). After 15 minutes of agitation, the slurry samples collected from the top and bottom portions of the vortex 402, the container is determined to have particle size distributions of 81.45 and 82.24 microns, respectively. Said particle size distribution is close to the actual mean size of silica particles i.e., 80 microns, thereby confirming the effective mixing in the special baffle attachment. A graph illustrating particle size distribution for top portion and bottom portions of the disclosed mixing system 302 is illustrated in FIG. 5. Also, Tables 3 and 4 impeller speed and mean particle sizes and Pulp densities of the sample, respectively for the disclosed mixing apparatus (for example, the mixing apparatus 302 of FIG. 3A).

Table 3: Impeller speed and mean particle sizes

Table 4: Pulp densities of the sample

[0051] Herein, it will be noted that in the disclosed embodiments, the vortex is formed due to the impeller action and the vortex formed is being disturbed by baffles by obstructing the rotational flow and making the vortex insignificant. In the case of conventional four baffled mixing as described with reference to FIGS. ID- IF, it is observed that there is no vortex formation. In the present disclosure, vortex is not diminished and there is a little disturbance to vortex due to protruding attachment which directs part of the top portion of the formed vortex towards the center of the vortex.

[0052] FIG. 6 illustrates a flow-diagram of a method 600 for mixing, in accordance with an example embodiment. At 602, the method 600 includes introducing a mixture of a plurality of ingredients in a mixing apparatus. The mixing apparatus includes a container to hold the plurality of ingredients to be mixed, an impeller assembly electrically connected to a motor and rotatably positioned in the container, and one or more protruding attachments removably supported within the container by a support mechanism, and further positioned to move in vertically upward and downward directions within the container. Herein, the mixing apparatus may be one of the mixing apparatus 302 of FIG.3A, the mixing apparatus 360 of FIG. 3B, or the mixing apparatus 370.

[0053] At 604, the method 600 includes stirring the mixture of the plurality of ingredients in the container by the impeller assembly. A motion of the plurality of ingredients due to stirring forms a vortex in the container. The vortex formed due to stirring is illustrated and described with reference to FIG. 4B. At 606, the method 600 includes redirecting , by the one or more protruding attachments, at least a portion of the plurality of ingredients between a top portion of the vortex and a bottom portion of the vortex. Herein, redirecting the at least a portion of the plurality of ingredients facilitates in mixing of the plurality of ingredients. The redirecting of the ingredients is illustrated and described with reference to FIG. 4A.

[0054] The foregoing description of the specific implementations and embodiments will so fully reveal the general nature of the implementations and embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

[0055] The preceding description has been presented with reference to various embodiments. Persons having ordinary skill in the art and technology to which this application pertains will appreciate that alterations and changes in the described structures and methods of operation can be practiced without meaningfully departing from the principle, spirit and scope.

Claims

CLAIMS We claim:

1. A mixing apparatus comprising:

a container for holding a plurality of ingredients to be mixed;

an impeller assembly electrically connected to a motor and rotatably positioned in the container for stirring the plurality of ingredients, wherein motion of the plurality of ingredients due to stirring forms a vortex in the container; and

one or more protruding attachments removably supported within the container by a support mechanism, and further positioned to move in vertically upward and downward directions within the container, wherein the one or more protruding attachments redirects at least a portion of the plurality of ingredients between a top portion of the vortex and a bottom portion of the vortex.

2. The apparatus as claimed in claim 1, wherein the support mechanism comprises a hinge assembly enclosed in a vertical grove configured in a wall of the container for hingedly holding the one or more protruding attachments.

3. The apparatus as claimed in claim 2, wherein the vertical grove facilitates the movement of the protruding attachment in the vertically upward and the downward directions.

4. The apparatus as claimed in claim 1, wherein the support mechanism is configured external to the container.

5. The apparatus as claimed in claim 4, wherein the support mechanism comprises a clamp assembly configured external to the container, and capable of holding the one or more protruding attachments.

6. The apparatus as claimed in claim 5, wherein a vertical movement of the clamp assembly facilitates in the movement of the protruding attachment in at least one of the vertically upwards and the downwards directions.

7. The apparatus as claimed in claim 1, wherein the movement of the protruding attachment in the vertically upward and the downward directions facilitates in adjusting position of the one or more protruding attachments to coincide with one of the top portion and the bottom portion of the vortex.

8. A method of mixing comprising:

introducing a mixture of a plurality of ingredients in a mixing apparatus, the mixing apparatus comprising:

a container to hold the plurality of ingredients to be mixed;

an impeller assembly electrically connected to a motor and rotatably positioned in the container; and

one or more protruding attachments removably supported within the container by a support mechanism, and further positioned to move in vertically upward and downward directions within the container;

stirring, by the impeller assembly, the mixture of the plurality of ingredients in the container, wherein motion of the plurality of ingredients due to stirring forms a vortex in the container; and

redirecting, by the one or more protruding attachments, at least a portion of the plurality of ingredients between a top portion of the vortex and a bottom portion of the vortex, wherein redirecting the at least a portion of the plurality of ingredients facilitates in mixing of the plurality of ingredients.