Claims:1. A particle separating apparatus (200) comprising a separation chamber (102) having a circumferential wall and characterized by an underflow end (108) as an outlet for coarse particles in a fluid and an overflow end (110) as an outlet for fine particles in the fluid, wherein the separation chamber (102) is provided with a deflecting means (116) disposed upstream from the underflow end (108) along the circumferential wall, the deflecting means (116) being configured to disengage and direct fine particle bypass sliding along the circumferential wall into an inner vortex and thereby towards the overflow end (108).

2. The particle separating apparatus of claim 1, wherein the deflecting means (116) comprises one or more annular rings disposed along the circumferential wall and protruding into the separation chamber (102), wherein the one or more annular rings are either concentric or eccentric with an axis of the separation chamber and are disposed with a gap therebetween.

3. The particle separating apparatus of claim 2, wherein the one or more annular rings are made of a flexible material.

4. The particle separating apparatus of claim 2, wherein the one or more annular rings are inclined towards the underflow end (108).

5. The particle separating apparatus of claim 2, wherein the one or more annular rings are of uniform dimensions or non-uniform dimensions.

6. The particle separating apparatus of claim 2, wherein the number of annular rings, dimensions thereof, position of the annular rings in the separation chamber and inclination of the annular rings are based on a desired separation efficiency.

7. A particle separating apparatus (300) comprising a separation chamber (102) having a circumferential wall and characterized by an underflow end (108) as an outlet for coarse particles in a fluid and an overflow end (110) as an outlet for fine particles in the fluid, wherein the circumferential wall, serving as a deflecting means (116), is corrugated and adapted to disengage and direct fine particle bypass sliding along the circumferential wall into an inner vortex and thereby towards the overflow end (108). , Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:

A PARTICLE SEPARATING APPARATUS

Applicant

Tata Consultancy Services Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
Nirmal Building, 9th floor,
Nariman point, Mumbai 400021,
Maharashtra, India

The following specification particularly describes the invention and the manner in which it is to be performed.


TECHNICAL FIELD
[001] The disclosure herein generally relates to particle separating apparatus, and, more particularly, to improving separation efficiency of a particle separating apparatus.

BACKGROUND
[002] Separation of gangue from minerals is an important step in mineral processing industries. Gravity separation techniques exploit differences in densities and sizes of particles containing different minerals to separate them, however, it has a limitation in treating finer size range of minerals (less than 100microns). Several centrifugal devices have been developed to separate fine size minerals such as Hydrocyclones, Triflo separators, Knelson separators, Falcon separators, and the like. Hydrocyclones gained popularity due to its simple design and low maintenance problems. The separation efficiency of Hydrocyclones has operational challenges such as the bypass of fine particles to the underflow and short circuiting of coarser material in to the overflow. Short circuiting of coarse particles to the overflow has been addressed by extending the spigot height or by changing the angle of the conical section of the Hydrocyclone. Separation efficiency has also been addressed by using chemical additives. Handling the bypass of fine particles to the underflow continues to be a challenge.

SUMMARY
[003] Embodiments of the present disclosure present technological improvements as solutions to one or more of the above-mentioned technical problems recognized by the inventors in conventional systems.
[004] In an aspect, there is provided a particle separating apparatus comprising a separation chamber having a circumferential wall and characterized by an underflow end as an outlet for coarse particles in a fluid and an overflow end as an outlet for fine particles in the fluid, wherein the separation chamber is provided with a deflecting means disposed upstream from the underflow end along the circumferential wall, the deflecting means being configured to disengage and direct fine particle bypass sliding along the circumferential wall into an inner vortex and thereby towards the overflow end.
[005] In an embodiment of the present disclosure, the deflecting means comprises one or more annular rings disposed along the circumferential wall and protruding into the separation chamber, wherein the one or more annular rings are either concentric or eccentric with an axis of the separation chamber and are disposed with a gap therebetween.
[006] In an embodiment of the present disclosure, the one or more annular rings are made of a flexible material.
[007] In an embodiment of the present disclosure, the one or more annular rings are inclined towards the underflow end.
[008] In an embodiment of the present disclosure, the one or more annular rings are of uniform dimensions or non-uniform dimensions.
[009] In an embodiment of the present disclosure, the number of annular rings, dimensions thereof, position of the annular rings in the separation chamber and inclination of the annular rings are based on a desired separation efficiency.
[010] In another aspect, there is provided a particle separating apparatus comprising a separation chamber having a circumferential wall and characterized by an underflow end as an outlet for coarse particles in a fluid and an overflow end as an outlet for fine particles in the fluid, wherein the circumferential wall, serving as a deflecting means, is corrugated and adapted to disengage and direct fine particle bypass sliding along the circumferential wall into an inner vortex and thereby towards the overflow end.
[011] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS
[012] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles.
[013] FIG.1 illustrates a schematic representation of a side elevational view of a particle separating apparatus as known in the art.
[014] FIG.2 illustrates a schematic representation of a cross-sectional elevational view of a particle separating apparatus similar to the particle separating apparatus of FIG.1.
[015] FIG.3 illustrates a schematic representation of a side elevational view of a particle separating apparatus, in accordance with an embodiment of the present disclosure.
[016] FIG.4 illustrates a schematic representation of a cross-sectional elevational view, in accordance with an embodiment of the present disclosure, of a particle separating apparatus similar to the particle separating apparatus of FIG.3.
[017] FIG.5 illustrates a schematic representation of a side elevational view of a particle separating apparatus, in accordance with another embodiment of the present disclosure.
[018] FIG.6 illustrates a graphical illustration of a comparison between number of particles reported in the overflow end in a conventional particle separating apparatus versus in a modified particle separating apparatus in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS
[019] Exemplary embodiments are described with reference to the accompanying drawings. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. Wherever convenient, the same reference numbers are used throughout the drawings to refer to the same or like parts. While examples and features of disclosed principles are described herein, modifications, adaptations, and other implementations are possible without departing from the spirit and scope of the disclosed embodiments. It is intended that the following detailed description be considered as exemplary only, with the true scope and spirit being indicated by the following claims.
[020] In the context of the present disclosure, the expression, a particle separating apparatus refers to an apparatus like Hydrocyclone or a Cyclone that can classify or separate fine particles and coarse particles in a fluid suspension. For ease of explanation, illustrations or descriptions may be limited to a Hydrocyclone or a Cyclone; however providing a deflecting means in accordance with the present disclosure is applicable to a gravity based particle separating apparatus or centrifugal particle separating apparatus in general. Accordingly, the expressions ‘inner vortex’ and ‘outer vortex’ used hereinafter refer to a stream carrying the fine particles and a stream carrying the coarse particles respectively in the particle separating apparatus.
[021] Referring now to the drawings, and more particularly to FIG.1 through FIG.6 where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments and these embodiments are described in the context of the following exemplary system and/or method.
[022] FIG.1 illustrates a schematic representation of a side elevational view of a particle separating apparatus 100 as known in the art. A conventional particle separating apparatus has a hollow separation chamber 102 with a circumferential wall. The separation chamber 102 is provided with a cylindrical portion 104 leading to a conical portion 106 and an underflow end 108, the cylindrical portion 104 being at an overflow end 110. A fluid feed is introduced tangentially through an inlet 112 provided at the top of the cylindrical portion 104. The particle separating apparatus 100 has two outlets. The conical portion ends with a narrow outlet referred to as a spigot at the underflow end 108. The second outlet (pipe) is a cylindrical outlet and referred to as a vortex finder at the overflow end 110. The vortex finder is connected to the top of the particle separating apparatus extending into the cylindrical portion of the particle separating apparatus.
[023] FIG.2 illustrates a schematic representation of a cross-sectional elevational view of a particle separating apparatus similar to the particle separating apparatus of FIG.1. During the operation of the conventional particle separating apparatus, two concentric vortices are formed. An outer vortex or a primary vortex (not shown) starts from the inlet and moves towards the narrow outlet at the conical portion end, while an inner vortex (secondary vortex) 114 moves towards the vortex finder.
[024] The outer vortex (primary vortex) carries coarse particles in the fluid to the underflow end whereas the inner vortex (secondary vortex) 114 carries fine particles in the fluid to the overflow end 110. During the separation process, some of the fine particles are carried away by the outer vortex to the underflow end 108 of the particle separating apparatus 100 and some of the fine particles slide along the wall of the separation chamber into the underflow end 108. The coarse or heavier particles in the fluid reporting to the vortex finder are normally referred to as misplaced or short circuited particles while the fine or lighter particles reporting into the underflow end 108 are referred as the fine particle bypass. The short circuited particles and the fine particle bypass are not desired and are indicative of the inefficiency of the particle separating apparatus. Separation efficiency of the particle separating apparatus is reduced due to the entrapment of the fine particles in the outer vortex. Traditionally, chemical additives have been introduced to improve the separation efficiency or length of the spigot has been increased to address short circuited particles. However, fine particle bypass continues to be a challenge.
[025] FIG.3 illustrates a schematic representation of a side elevational view of a particle separating apparatus 200 and FIG.4 illustrates a schematic representation of a cross-sectional elevational view of a particle separating apparatus similar to the particle separating apparatus of FIG.3, in accordance with an embodiment of the present disclosure. The particle separating apparatus 200 of FIG.4 comprises a separation chamber 102 having a circumferential wall and characterized by an underflow end 108 as an outlet for coarse particles in a fluid and an overflow end 110 as an outlet for fine particles in the fluid. In accordance with an embodiment of the present disclosure, the separation chamber 102 is provided with a deflecting means 116 disposed upstream from the underflow end 108 along the circumferential wall, wherein the deflecting means 116 is configured to disengage and direct fine particle bypass sliding along the circumferential wall into an inner vortex and thereby towards the overflow end 110 instead of reporting into the underflow end 108 as seen in the art. The deflecting means 116 is thus adapted to avert reduction in separation efficiency of the particle separating apparatus 200 due to entrapment of the fine particles in the outer vortex.
[026] In accordance with an embodiment of the present disclosure, the deflecting means 116 comprises one or more annular rings disposed along the circumferential wall and protruding into the separation chamber. In an embodiment, the annular rings are either concentric or eccentric with an axis of the separation chamber and are disposed with a gap provided between the annular rings. The positions of the annular rings or the gap between them may be based on a desired separation efficiency. The deflection means of the present disclosure provide two functions. On one hand the deflection means direct the sliding fine particles into the inner vortex of the particle separating apparatus toward the intended overflow end. On the other hand, the reporting of fine particles carried by the outer vortex into the underflow causing reduced separation inefficiency is minimized.
[027] In accordance with an embodiment of the present disclosure, the one or more annular rings are made of a flexible material. Flexibility of the material may further affect the deflection of the fluid flow and accordingly the fine particles.
[028] In accordance with an embodiment of the present disclosure, the one or more annular rings are inclined (FIG.3) towards the underflow end. In an embodiment, the one or more annular rings may be inclined at an angle ranging from 0 deg. to 45 deg. depending on the desired separation efficiency.
[029] In accordance with an embodiment of the present disclosure, the one or more annular rings are of uniform dimensions or non-uniform dimensions. For instance, the annular rings towards the spigot may be of a smaller width as the available radius for flow of the fluid itself is small towards the underflow end. In an embodiment, the dimensions of the annular rings may be defined based on the desired separation efficiency which in turn depends on the fine particle bypass existing for the fluid being used in the particle separating apparatus. Typically very thin rings have been seen to provide a necessary deflection. Again, the number of annular rings can be varied, depending on the bypass of the fine particles to the underflow end and the desired separation efficiency.
[030] In accordance with another embodiment of the present disclosure, a particle separating apparatus 300 is provided that comprises a separation chamber 102 having a circumferential wall and characterized by an underflow end 108 as an outlet for coarse particles in a fluid and an overflow end 110 as an outlet for fine particles in the fluid. In the illustrated embodiment, the circumferential wall of the particle separating apparatus 300 serves as a deflecting means 116. The circumferential wall is corrugated and adapted to disengage and direct fine particle bypass sliding along the circumferential wall into an inner vortex and thereby towards the overflow end 108. FIG.5 illustrates a schematic representation of a side elevational view of the particle separating apparatus 300, in accordance with another embodiment of the present disclosure
[031] The particle separating apparatus 200 of the present disclosure with the deflecting means in the form of annular rings was validated using Lagrangian modelling by injecting silica slurry having particles of varying size range (0.1µm to 10µm) into the particle separating apparatus 200 and also into the conventional particle separating apparatus 100. Number of particles reported at the overflow end and at the underflow end was tracked for both the apparatus. FIG.6 illustrates a graphical illustration of a comparison between number of particles reported in the overflow end in a conventional particle separating apparatus versus in a modified particle separating apparatus in accordance with an embodiment of the present disclosure. Table provided below illustrates results of the Lagrangian particle tracking for the conventional particle separating apparatus and the modified particle separating apparatus in accordance with an embodiment of the present disclosure.
Table: Results of the Lagrangian particle tracking.
Particle Diameter
(µm) Total No. of Particles Conventional apparatus (100) Apparatus of the present disclosure (200)
Overflow Underflow Overflow Underflow
0.1 861 72 790 155 697
0.2 861 66 795 140 710
0.3 861 57 804 128 722
0.4 861 48 813 114 739
0.5 861 47 814 83 767
0.6 861 43 818 67 783
1 861 38 823 63 792
2 861 37 824 60 791
5 861 29 832 57 799
6 861 8 853 61 795
7 861 0 861 32 826
8 861 0 861 35 825
9 861 0 861 21 834
10 861 0 861 2 859
[032] It was noted that the fine particles that were otherwise carried away by the outer vortex in a conventional particle separating apparatus 100 towards the underflow end were now directed towards the inner vortex of the particle separating apparatus 200 and guided towards the overflow end. As seen from the table above, there is an increase in the no. of particles reported at the overflow end in the modified particle separating apparatus 200 of the present disclosure thereby improving the associated separation efficiency.
[033] Thus in accordance with an embodiment of the present disclosure, providing the deflecting means as explained with reference to FIG.3 through FIG.5 is a low cost solution for reducing fish hook behavior typically seen in a separation efficiency curve. In an embodiment, the fine particle bypass may be controlled by configuring the number of annular rings, dimensions of the annular rings, position of the annular rings in the separation chamber and inclination of the annular rings suitably to achieve the desired separation efficiency.
[034] The written description describes the subject matter herein to enable any person skilled in the art to make and use the embodiments. The scope of the subject matter embodiments is defined by the claims and may include other modifications that occur to those skilled in the art. Such other modifications are intended to be within the scope of the claims if they have similar elements that do not differ from the literal language of the claims or if they include equivalent elements with insubstantial differences from the literal language of the claims.
[035] The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope and spirit of the disclosed embodiments. Also, the words “comprising,” “having,” “containing,” and “including,” and other similar forms 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. 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.
[036] It is intended that the disclosure and examples be considered as exemplary only, with a true scope and spirit of disclosed embodiments being indicated by the following claims.