CLIAMS:WHAT IS CLAIMED IS:
1. An apparatus, the apparatus comprising:
a central axis 102;
a hollow annular tube 104, the tube 104 being symmetrical about the central axis 102, the tube 104 further comprising:
a surface 104a;
two or more identical fluid ejection apertures 108, each of the fluid ejection apertures108 having a geometrical centre and an axis 102a passing through the geometrical centre, each of the fluid ejection apertures 108 being symmetrical about its respective axis, each of the fluid ejection apertures 108 being positioned symmetrically around the central axis 102 and, geometrical centres of the fluid ejection apertures 108 being coplanar;
two or more identical inlet apertures 110, the inlet apertures 110 being symmetrical in shape, and being positioned symmetrically around the central axis 102,
two or more identical inlet pipes 106, count of the inlet pipes 106 being equal to count of the inlet apertures 110, and each inlet pipe 106 covering one inlet aperture 110 wherein,
a longitudinal axis 112 of each of the inlet pipes 106 makes an angle of 45 degrees with a tangent 132 at the geometrical centre of virtual portion of the surface 104a which covers corresponding inlet aperture110 of the inlet pipe 106;
the longitudinal axis 112 of the inlet pipe 106 and the tangent 132 are coplanar; and
the fluid ejection apertures 108 being formed such that during ejection of a fluid from the ejection apertures 108, a uniform rate of flow of fluid is maintained across all fluid ejection apertures 108, and, jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures 108, are directed towards the central axis 102 in a manner such that the direction of each jet of ejected fluid is along the axis of its corresponding ejection aperture 108.
2. The apparatus as claimed in claim 1, wherein the geometrical centres of the virtual portions of the surface 104a corresponding to each of the inlet apertures 110 are coplanar.
3. The apparatus as claimed in claim 1, wherein in shape of cross-section of the hollow annular tube 104, the cross-section being taken along a plane on which the central axis 102 lies, is circular.
4. The apparatus as claimed in claim 3, wherein in shape of cross-section of each of the inlet pipes 106, the cross-section being taken along a plane which is perpendicular to the longitudinal axis 112 of the inlet pipe 106, is circular.

5. The apparatus as claimed in claim 4, wherein in diameter of the inlet pipe 106 is ≤ D1,
D1 being diameter of a cross-section of the hollow annular tube 104, the cross-section being taken along a plane on which the central axis 102 lies.

Dated: 11th Day of March, 2015 Signature
Arun Kishore Narasani Patent Agent ,TagSPECI:FIELD OF THE INVENTION

[001] The present invention relates to fluid diffusers. More particularly, the present invention relates to a fluid diffuser which, during ejection of a fluid, maintains a uniform rate of flow of fluid across all its fluid ejection apertures and, in which all jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures, are directed towards a central axis of the diffuser in a manner such that the direction of each jet of ejected fluid is along an axis of corresponding fluid ejection aperture.
BACKGROUND
[002] Optical fiber and optical fiber cables are backbone of modern communication infrastructure and systems. Our reliance on optical fibers for telecommunications, broadband communication, communication over passive optical networks, sensor applications, medicinal & surgical applications, and the like is growing day by day. A good quality optical fiber which at least meets (or more preferably, exceeds) requirements for reliable and satisfactory performance is extremely necessary to serve ever increasing load on optical communications. Manufacturing process of good quality optical fiber requires a series of successful execution of various extremely sensitive sub-processes. Even a slight non-compliance from accepted standards or deviation from desired quality standard at one of the sub-processes may show up and can spoil the entire product.
[003] Typically, the silica (or glass) optical fibers are produced by placing cylindrical glass preforms vertically in a furnace of an optical fiber draw tower, and then drawing glass optical fibers from a heated tapered end of the glass preform. In a following sub-process, the drawn optical fiber (which could have a temperature of more than 2000°C) is exposed to cooling gases for lowering its temperature to a desired level. It is well known that efficient, uniform and time bound cooling of the drawn optical fiber enhances its physical properties (for example: strength, refractive index, etc.), and keeps it well prepared for the next sub-process (say, for application of protective coatings over the drawn optical fiber). However, if the drawn optical fiber is not cooled evenly and uniformly around its entire outer surface, defects such as internal stresses, core/cladding ovality and micro-cracks may get in to the optical fiber. These defects increase transmission losses of the optical fiber, and may also reduce its physical strength.
[004] In an optical fiber draw tower, cooling of a continually drawn and (transitioning) and drawn optical fiber is done by using cooling fluid diffusers. Structurally, the diffuser body includes a hollow container and inlets for providing cooling fluid within the container. The diffuser body is symmetrical about a central axis. Further, the diffuser includes one or more fluid ejection apertures which eject jets of cooling fluid towards the central axis. In an optical fiber draw tower, the continually drawn heated optical fiber is made to pass along the axis of the diffuser, so that jets of cooling fluids ejected by each of the apertures hit the surface optical fiber and cool it.
[005] Various equipments have been used in the past to facilitate cooling of continually drawn optical fibers in an optical fiber draw tower. US patent 4,894,078 discloses (‘078 patent) a method and apparatus for producing optical fiber using a perforated helical spiral pipe laid around the optical fiber to provide cooling. This cooling apparatus as proposed in ‘078 patent is complex, space consuming, requires high degree of manufacturing and installation accuracy. Moreover, the cooling apparatus as proposed in ‘078 patent does not maintain a uniform rate of ejection of cooling fluid at all fluid ejection holes/apertures. The cooling apparatus as proposed in ‘078 patent does not ensure efficient cooling of the optical fiber. Another US patent 7,823,419 (‘419 patent) discloses an optical fiber drawing furnace which has provisions for providing uniform flow of inert gas inside the furnace. However, the furnace disclosed in ‘419 patent, is a complex structure and its installation and usage in existing optical fiber draw towers requires either a lot of modifications in the existing set-up or a complete replacement of the furnace setup. Apart from replacement / modifications, the proposed furnace of ‘419 patent is space consuming and its installation may not be viable at installed draw towers suffering from space crunch. Hence the furnace of ‘419 patent would be difficult to be installed and implemented at existing optical fiber draw tower set-ups. Similarly, published US application 2002/088,253 (‘253 application) discloses a furnace equipped with provisions for supplying cooling gases during stretching a preform within the furnace (or during drawing of an optical fiber from the preform). Again, the disclosed furnace design in the (‘253 application), is a complex structure and requires either requires a complete replacement of the furnace or requires a lot of modifications in an existing optical fiber draw tower set-up. Apart from replacement/modifications, the proposed furnace of ‘253 application would also require more space. Hence the furnace of ‘253 application would also be difficult to be adopted and implemented on existing optical fiber draw tower set-ups. Another patent publication, US patent 5,366,530 (‘530 patent) discloses a preform manufacturing apparatus which includes provisions for supplying cooling gases around the preform being manufactured (said preform is a longitudinal body which passes through an axis of the disclosed apparatus). The disclosed apparatus does not ensure uniform cooling around entire surface of the preform.
[006] Though various apparatus/equipments have been proposed in the past for facilitating cooling of continually drawn optical fibers (or a preform), all proposed apparatus/equipments either do not facilitate uniform rate of fluid ejection from each of their apertures so as to enable uniform and efficient cooling around the surface of the optical fiber (or preform), or are too complex or difficult to implement in existing optical fiber draw tower setup. Moreover, even a planned new draw tower set-up would also desire a relatively simple and efficient apparatus which would cool a drawn optical fibre uniformly across its surface. Hence, there is acute need for an apparatus which would:
a) facilitate uniform and efficient cooling of a drawn optical fiber in an optical fiber draw tower,
b) be simple in design, and
c) which would also be compatible for being used in existing draw tower set-ups without many modifications.
OBJECTS OF THE INVENTION
[007] It is an object of the present invention is to provide a fluid diffuser which, during ejection of fluid from its fluid ejection apertures, would maintain a uniform rate of flow fluid across all its fluid ejection apertures.
[008] It is an object of the present invention is to provide a fluid diffuser in which all jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures of the diffuser, are directed towards a central axis of the diffuser in a manner such that direction of each jet of ejected fluid is along an axis of a corresponding fluid ejection aperture.
[009] It is an object of the present invention to provide a fluid diffuser which, during ejection of a fluid through its fluid ejection apertures, maintains uniform rate of flow of fluid across all its fluid ejection apertures and, in which all jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures, are directed towards a central axis of the diffuser in a manner such that direction of each jet of ejected fluid is along an axis of a corresponding fluid ejection aperture.
[0010] It is an object of the present invention is to provide a fluid diffuser which is simple to use and easy to deploy in an optical fiber draw tower and which would facilitate uniform cooling of an optical fiber passing through a central axis of the fluid diffuser.
[0011] It is an object of the present invention is to provide a fluid diffuser which is simple to use, easy to deploy, which would eject a fluid at an uniform rate of flow from all fluid ejection apertures of the diffuser and, in which all jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures, are directed towards a central axis of the diffuser in a manner such that direction of each jet of ejected fluid is along an axis of a corresponding fluid ejection aperture.
[0012] It is object of the present invention is to provide an apparatus which would facilitate uniform cooling around surface of a transiting heated longitudinal body of circular cross-section, said body being placed along a central axis of the apparatus, and said body being moving along the central axis of the apparatus.
[0013] It is an object of the present invention to provide a fluid diffuser which, during ejection of a fluid through its fluid ejection apertures, would facilitate uniform cooling of a surface of a non-stationary heated longitudinal body, said body having a circular cross-section and passing through a central axis of the fluid diffuser,by maintaining uniform rate of flow of cooling fluid across all fluid ejection apertures and, in which all jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures, are directed towards the central axis of the diffuser in a manner such that direction of each jet of ejected fluid is along an axis of corresponding fluid ejection aperture.
[0014] Another object of the present invention is provide an apparatus which would reduce transmission losses of an optical fiber by reducing defects in the optical fiber which are caused due to uneven/non-uniform cooling of the optical fiber in an optical fiber draw tower.
[0015] Another object of the present invention is to improve physical strength of an optical fiber by reducing defects in the optical fiber which are caused due to uneven/non-uniform cooling of the optical fiber in an optical fiber draw tower.
[0016] Yet another object of the present invention is to provide a fluid diffuser which would eject a fluid at an uniform srate of flow from all fluid ejection apertures of the diffuser, and which, when installed in an optical fiber draw tower, could be used to provide uniform cooling to a continually drawn optical fiber passing through a central axis of the diffuser.
SUMMARY
[0017] In order to overcome drawbacks of cited prior art and to meet the objects of the invention, the present invention provides a simple and easy-to-deploy fluid diffuser which, during ejection of a fluid through its fluid ejection apertures, would maintain an uniform rate of flow of fluid across all its fluid ejection apertures and, in which all jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures, are directed towards a central axis of the diffuser in a manner such that direction of each jet of ejected fluid is along an axis of corresponding fluid ejection aperture.
[0018] Embodiments of the fluid diffuser provided by the present invention may be deployed in an optical fiber draw tower and can be used to uniformly cool a continually drawn optical fiber around its surface by ejecting identical jets of cooling fluid through its fluid ejection apertures.
[0019] An embodiment of the fluid diffuser in accordance with the present invention is placed in an optical fiber draw tower in a manner such that the drawn optical fiber passes along a central axis of the diffuser. Thereafter, cooling fluid is pumped in to the diffuser through hollow fluid inlet pipes. The design and structure of the diffuser ensures that the cooling fluid exits the diffuser through fluid ejection apertures in a manner such that the fluid is ejected at a uniform flow rate from all fluid ejection apertures and, all jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures, are directed towards the central axis (or the optical fiber), in a manner such that the direction of jet of ejected fluid is along an axis of corresponding fluid ejection aperture.
[0020] According to an embodiment of the present invention, a fluid diffuser comprises:
a central axis;
a hollow annular tube, the tube being symmetrical about the central axis, the annular tube having a circular cross-section, the cross-section being taken along a plane on which the central axis lies, the tube further comprising:
a surface
two identical fluid ejection apertures, each of the fluid ejection apertures having a geometrical centre and an axis passing through the geometrical centre, each of the fluid ejection apertures being symmetrical about its respective axis, each of the fluid ejection apertures being positioned symmetrically around the central axis and, geometrical centres of the fluid ejection apertures being coplanar;

two identical inlet apertures, the inlet apertures being symmetrical in shape, and being positioned symmetrically around the central axis,

two identical inlet pipes, diameter of each of the inlet pipes being ≤ D, D being diameter of a largest circle which may be inscribed within the cross- section of the annular tube, each inlet pipe covering one inlet aperture wherein,
a longitudinal axis of each of the inlet pipes makes an angle of 45 degrees with a tangent at geometrical centre of virtual portion of the surface which covers corresponding inlet aperture of the inlet pipe;

the longitudinal axis of the inlet pipe and the tangent are coplanar; and

the fluid ejection apertures being formed such that during ejection of a fluid from the ejection apertures, a uniform rate of flow of fluid is maintained across all fluid ejection apertures, and, jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures, are directed towards the central axis in a manner such that the direction of each jet of ejected fluid is along the axis of its corresponding ejection aperture.
More details of the invention and its embodiment will be described in detailed description provided in following paragraphs with references to accompanying figures.
BRIEF DESCRIPTION OF THE FIGURES

[0021] FIG. 1 illustrates a three dimensional view of a first embodiment of a fluid diffuser in accordance with the present invention.
[0022] FIG. 2 illustrates a three dimensional view of hollow annular tube of the fluid diffuser prepared in accordance with the first embodiment of the present invention.
[0023] FIG. 3 illustrates a vertical cross-sectional view of the fluid diffuser in accordance with the first embodiment of the present invention.
[0024] FIG. 4a-4b illustrate sectioning of the first embodiment of fluid diffuser in accordance with the present invention in order to obtain the vertical cross-sectional view as illustrated in FIG. 3.
[0025] FIG. 5 illustrates a horizontal cross-sectional view of the fluid diffuser in accordance with the first embodiment of the present invention.
[0026] FIG. 6a-6b illustrate sectioning of the first embodiment of fluid diffuser in accordance with the present invention in order to obtain the horizontal cross-sectional view as illustrated in FIG. 5.
[0027] FIG. 7 illustrates flow of fluid within an operational first embodiment of fluid diffuser prepared in accordance with the present invention.
[0028] It should be noted that the accompanying figures are intended to provide a better understanding of embodiment of the present invention. These figures are not intended to limit the scope of the present invention. It should also be noted that accompanying figures are for the purpose of illustration only and are not necessarily drawn to scale. For example, the size of some of the components in the figures may be exaggerated, relative to others in order to improve the understanding of the present invention. Accompanying figures are intended to provide a clear understanding of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS
[0029] The invention is described in detail below in conjunction with the accompanying figures. It is to be noted that terminology used throughout the specification and claims herein are given their ordinary meanings. Those with ordinary skill in the art will appreciate that the elements in the figures are illustrated for simplicity and clarity. There may be additional components described in the foregoing application that are not depicted on one of the described drawings. In the event such a component is described, but not depicted in a drawing, the absence of such a drawing should not be considered as an omission of such design from the specification.
[0030] As required, detailed embodiment of the present invention is disclosed herein; however, it is to be understood that the disclosed embodiment is exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.
[0031] While the specification concludes with the claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawings, in which like reference numerals are carried forward.
[0032] It should be noted that term ‘hollow annular tube’ as used in herein in relation to the invention (throughout the text provided herein below) refers to a hollow tube which necessarily includes following features:
i. The hollow tube surrounds a central axis, the central axis lies outside the hollow tube, and
ii. Shape of a cross-section of the hollow tube, the cross-section being taken along a plane on which the central axis lies, is symmetrical.
Reference will now be made in detail to an embodiment of the present invention in conjunction with accompanying figures.
[0033] FIG. 1, 2, 3, 4a, 4b, 5, 6a, 6b and 7 provide illustrations relating to a first embodiment of a fluid diffuser 100 in accordance with the present invention. FIG. 1 illustrates a three dimensional view of a fluid diffuser 100 entirely made of stainless steel.As shown in the figure, diffuser 100 includes a central axis 102, a hollow annular tube 104, two hollow inlet pipes 106 and six fluid ejection apertures 108. All fluid ejection apertures 108 are symmetrical in shape, identical with each other, and are distributed symmetrically around axis 102. Each fluid ejection aperture 108 further comprises of a geometrical centre ‘C’, and all geometrical centres ‘C’ of respective fluid ejection apertures 108 are coplanar. Further, each fluid ejection aperture 108 is symmetrical about an axis 102a passing through its respective geometrical centre ‘C’. An explicit illustration of the fluid ejection apertures 108 with their respective geometrical centres is provided in FIG. 3. In the illustration of FIG.1; only three of the six fluid ejection apertures 108 are visible. Diffuser 100 is symmetrical about the central axis 102. The central axis 102 lies outside the diffuser 100 and is surrounded by the hollow annular tube 104 .It is to be noted that the central axis 102 and the axis 102a do not represent any physical component of the diffuser 100. The annular tube 104 further includes two inlet apertures 110.Sinceeach of the inlet apertures 110 is covered by one end of an inlet pipe 106, the inlet apertures 110 are not visible in FIG. 1. In other words, the inlet apertures 110 are hidden under junction of respective inlet pipe 106 and the hollow annular tube 104. A fluid to be ejected by the fluid ejection apertures 108 of the diffuser 100 is continuously supplied to the annular tube 104 by the inlet pipes 106. The supplied fluid enters the annular tube 104 through the inlet apertures 110 and exits the annular tube 104 by the fluid ejection apertures 108. The annular tube 104 and each inlet pipe 106 are all made of stainless steel. Further, each inlet pipe 106 is symmetrical about a longitudinal axis 112, and shape of cross-section of each of the inlet pipe 106, the cross-section being taken along a plane which is perpendicular to the longitudinal axis 112, is circular. FIG. 1 illustrates the longitudinal axis 112 passing through corresponding inlet pipe 106. It is to be noted that the longitudinal axis 112 does not represent any physical component of either the corresponding inlet pipe 106 or the diffuser 100. The hollow annular tube 104 has a surface 104a and further includes a hollow space 104b. The hollow space 104b lies within and surrounded by surface 104a of the annular tube 104. In the diffuser 100, the inlet apertures 110 remain hidden and covered by a leak proof joint by the inlet pipes 106. Each of the inlet apertures 110 are formed on the annular tube 104 by removing/cutting a desired portion having a specific shape from the surface 104a of annular tube 104. Shape of each of the inlet aperture 110 is identical, symmetrical, and dimensionally similar. For a better understanding, a three dimensional view of only the annular tube 104, i.e. the annular tube 104 (having the inlet apertures 110 and the fluid ejection apertures 108 formed), without attached inlet pipes 106 is illustrated in FIG. 2. To further strengthen the understanding of structure of the present embodiment of the invention, three hidden fluid ejection apertures 108 (which are not illustrated in FIG. 1) are also illustrated in FIG. 2. However, for simplicity the axis 102a of each of the three hidden fluid ejection apertures 108 are not illustrated in FIG. 2.
[0034] FIG. 3 illustrates a first cross-section of the fluid diffuser 100 taken along a plane on which the central axis 102 lies, the plane is oriented in a manner such that it symmetrically divides the fluid diffuser 100 in two identical and equal halves. In other words, cross-section of the fluid diffuser 100 is taken along the plane which is coplanar with the central axis 102. For simplicity of representation, among various possibilities, a cross-sectioning plane which does not pass through any of the inlet pipes 106 or any of the fluid ejection apertures 108 or any of the inlet apertures 110 was chosen. To further support illustration and description relating to FIG. 3, a three dimensional view of the fluid diffuser being cut by a cross-sectioning plane 114, in a manner as described is illustrated in the FIG. 4a and FIG. 4b. The plane 114 divides the diffuser 100 in two identical and equal portions i.e. portion 114a and 114b as shown in FIG. 4b. The cross-section illustrated in the FIG.3 illustrates a front view of the portion 114a.
[0035] As shown in the FIG. 3, the portion 114a includes two cross-sectional peripheries 116 of the hollow annular tube 104. It is to be noted that the peripheries 116 are cross-sectional representations of the hollow annular tube 104. Each of the two cross-sectional peripheries 116 are circular in shape and have a diameter D1. Also illustrated in the FIG. 3 is one of the input apertures 110. The FIG. 3 also illustrates the three fluid ejection apertures 108 along with their respective geometrical centres ‘C’ (other three fluid ejection apertures 108 lie on the portion 114b (hence are not visible in FIG. 3). All the geometrical centres ‘C’ are coplanar. It is also to be noted that the illustrated geometrical centres ‘C’ do not represent any physical component of the diffuser 100.
[0036] FIG. 5 illustrates a second cross-section of the fluid diffuser 100. The cross-section illustrated in the FIG. 5 is taken along a plane which is perpendicular to the central axis 102 and the plane being oriented in a manner such that it symmetrically divides the fluid diffuser 100 in two equal and identical halves. By virtue of structure, each of the axis 102a is coplanar with the plane, To further support illustration and description relating to the FIG. 5, a three dimensional view of the fluid diffuser 100 being cut by a cross-sectioning plane 118, is illustrated in FIG. 6a and FIG. 6b. The plane 118 divides the fluid diffuser 100 in two equal and identical halves namely 120a and 120b. FIG. 6b illustrates the upper half 120a and the lower half 120b. The FIG. 5 illustrates a top view of the lower half 120b. As mentioned above, the plane 118 is coplanar with each of the axis 102a of each of the fluid ejection apertures 108.
[0037] In the FIG. 5, while the lower half 120b is represented by peripheries 122 and 124, periphery 126 represents cross-section of each inlet pipe 106. In other words, while the peripheries 122 and 124 represent cross-sections of surface 104a, periphery 126 represents cross-section of each inlet pipe 106. Two longitudinal axis 112 one each for inlet pipe are also illustrated. Also illustrated in cross section of FIG. 5 are virtual peripheries 128. The virtual peripheries 128 are a cross-sectional representation of virtual of portion of surface 104a which was removed to form a corresponding inlet aperture 110. It is also to be noted that the virtual peripheries 128 does not represent any physical component of the diffuser 100 (hence the name ‘virtual’). The virtual peripheries 128 simply represent cross-sectional peripheries of a virtual portion of surface 104a which were removed for providing the corresponding inlet apertures 110 on the annular tube 104. The FIG. 5 also illustrates cross-sectional peripheries 130. Each periphery 130 is a cross-sectional illustration of the corresponding fluid ejection apertures 108. Geometrical centres ‘C’ of each of the fluid ejection apertures 108 is also illustrated in FIG. 5. As illustrated, each geometrical centre ‘C’ is partially surrounded by corresponding periphery 130. Further, as illustrated in the FIG. 5, the cross-sectional span of each fluid ejection aperture 108 is represented by ‘d1’. In the FIG. 5, two dotted lines 132 represent tangents to the geometrical centre ‘P’ and ‘Q’ of the peripheries 128. It is to be noted that since the FIG.5 represents a cross-section of the diffuser 100 as described, point ‘P’ and point ‘Q’ also represent the geometrical centres of respective inlet apertures 110 related to corresponding peripheries 128. In this embodiment the inlet apertures 110 were prepared such that the points ‘P’, ‘Q’ and all the geometrical centres ‘C’ are coplanar. It is to be understood that each of the geometrical centre ‘C’ and geometrical centres of each Virtual peripheries 128, (and of inlet apertures 110) i.e. geometrical centres ‘P’ and ‘Q’ do not represent a physical quantity within the diffuser 110.
[0038] In an exemplary scenario, each inlet apertures 110 were made identical to each other and were placed symmetrically on the annular tube 104 during manufacturing. Next, as mentioned before, six identical fluid ejection apertures 108 (three of them are visible in FIG.1) were also prepared on the annular ring 104 to lie symmetrically around the central axis 102. Each of the fluid ejection apertures 108 were identical in shape and dimensions. Further, shape of each fluid ejection aperture 108 was symmetrical about an axis 102a passing through its corresponding geometrical centre ‘C’. Each of the fluid ejection apertures 108 were provided on the annular ring such that:
i. Their respective geometrical centres ‘C’ were equidistant from the central axis 102 (i.e. the shortest distance between geometrical center ‘C’ of each fluid ejection aperture 108 and the central axis 102 was same), and
ii. All the geometrical centres ‘C’, their respective axis 102a, and the periphery 124 were coplanar.
[0039] Once symmetrically placed identical inlet apertures 110 and the fluid ejection apertures 108 are formed on surface 104a, as described above and illustrated in the FIG. 5, each inlet pipe 106 was attached over a corresponding inlet aperture 110 in a manner such that:
i. The longitudinal axis 112 of each inlet pipe 106 made an angle of 45° with a tangent 132 at the geometrical center (i.e. geometrical centres ‘P’or‘Q’) of the corresponding inlet aperture 110 (or virtual portion of surface 104a which covers corresponding inlet aperture 110). This is illustrated explicitly in the FIG. 5. As depicted in the figure, angle APM=angle NQB=45°.
ii. Each of the longitudinal axis 112 and each of the tangents 132 were coplanar (i.e. all four straight lines AP, MP, BQ and NQ were coplanar); and
iii. Each of the tangent 132 did not lie in contact with the annular tube 104 at any point except at the geometrical centres ‘P’ or ‘Q’.

[0040] It is to be noted that the axis 112 (and corresponding line segments AP and NQ), tangents 132 (i.e. MP and BQ), the periphery 128 and the geometrical centres ‘P’ and ‘Q’ do not represent any physical quantity within the diffuser 100. However, mathematically they play a very important role for manufacturing the diffuser 100. For example, though it was cumbersome to directly measure the values of angles APM and NQB, dimensions of components of diffuser 100 which would be achieved after obeying above constraints were easily back calculated.

[0041] It was also ensured that, diameter of the inlet pipe 106 was chosen such that it remains less than D1, D1 being diameter of peripheries 116 as explained and illustrated in FIG. 3.‘D1’ can also be described as the diameter of the largest circle which can be inscribed within the periphery 116. The dimensions of each of the inlet apertures 110 were also chosen to fit the structural and geometrical constraints described above.
[0042] Dimensional details of the fluid diffuser 100 made in accordance with the first embodiment of the invention is listed in Table 1 below.

TABLE 1: Dimensional details

S. No. Portion or component of diffuser 100 Dimensions
1 Outer diameter of hollow annular tube 104 (illustrated as ‘W1’ in FIG. 5) 135 mm
2 Inner diameter of hollow annular tube 104 (illustrated as ‘W2’inFIG. 5) 125 mm
3 Axial length of inlet pipes 106
(illustrated as ‘L1’inFIG. 5) 20 mm
4 Diameter of peripheries116
(illustrated as ‘D1’in FIG. 3) 2.5 mm
5 Diameter of inlet pipes 106
(illustrated as ‘D2’in FIG. 5) 4 mm
6 Span of fluid ejection aperture in cross-section of FIG. 5
(illustrated as ‘d1’ in FIG. 5) 2mm
7 Thickness of surface 104a made of stainless steel
(illustrated as ‘T1’in FIG. 3) 0.3 mm

[0043] With the above mentioned constraints and dimensions, ends of the hollow inlet pipes 106 were attached over the corresponding inlet apertures 110 in a manner as described above to provide a leak proof joint with the annular tube 104. To provide a perfect joint, shape of the corresponding end of the inlet pipe 106 which would cover the aperture 110 was suitably worked to map and fit on the periphery of the target inlet aperture 110 to be covered.In other words, ends each of the inlet pipe 106 (which were to be attached with the hollow annular ring 104 over corresponding inlet apertures 110) were worked and shaped to match with periphery of corresponding inlet apertures 110 for being attached with the annular tube 104 for covering corresponding inlet apertures 110.

[0044] Finally, once manufactured in accordance with an exemplary embodiment described herein, the hollow inlet pipes 106 were used to supply a fluid (say, a cooling fluid such as cooled Nitrogen, or Helium) from a reservoir (not shown in the accompanying figures) into the hollow annular tube 104 through the inlet apertures 110. Functionally, a jet of fluid which was supplied through the inlet pipes 106, entered the diffuser 100 from the inlet apertures 110, and exits the diffuser 100 through the fluid ejection apertures 108.
[0045]
[0046] Fluid ejection analysis and flow pattern of the Fluid Diffuser 100 (having dimensions as provided in Table 1 above) was studied using ANSYSFluent®simulation software. Simulation results showed that irrespective of the rate of supply of cooling fluid into the inlet pipes 106 (i.e. volume of fluid pumped to the inlet pipes per unit time), all the fluid ejection apertures 110 uniformly ejected identical fluid jets in a manner such that:
i. Each jet of ejected fluid wasdirected towards the central axis 102 in a manner such that the direction of the jet was along the axis 102a of its corresponding fluid ejection aperture108
ii. All jets were ejected with an identical trajectory.

[0047] Mentioned simulation also illustrated flow path of fluid within the diffuser 100 (right from its entry in to the inlet pipes 106 to its ejection from the fluid ejection apertures 108) is illustrated in FIG. 7 by dotted arrows 134. In the FIG. 7, it is to be noted that within the periphery 124 the flow path illustrated by dotted lines 134 coincides with axis of corresponding fluid ejection apertures 108. It should be noted that the dotted arrows 134 as shown in the FIG. 7 do not represent any physical component or quantity within the fluid diffuser 100. The dotted arrows 134 simply represent the flow path and direction of fluid within the diffuser 100.
[0048] The arrangement of the inlet pipes 106, the inlet apertures 110 and the fluid ejection apertures 108 as described in the first embodiment of the invention, ensures that irrespective of location and relative distance of each of the fluid ejection apertures 108 from any of the inlet apertures 110, fluid is ejected evenly (and with a similar flow trajectory) from all the fluid ejection apertures 108 towards the central axis 102 in a manner as described.
[0049] The design and structure of the diffuser 100 ensures that the cooling fluid exits the diffuser 100 through the fluid ejection apertures 108 in a manner such that the fluid is ejected at a uniform flow rate from all the fluid ejection apertures 108 and, all jets of ejected fluid, each jet being ejected from one of the fluid ejection apertures 108, are directed towards the central axis 102, in a manner such that the direction of a jet of ejected fluid is along the axis 102a of its corresponding fluid ejection aperture 108 and each of said ejected jets has similar angular orientation with respect to the central axis 102.
[0050] The Fluid Diffuser 100 (having dimensions as provided in Table 1 above) was installed and tested in a running on-site optical fiber draw tower set-up for uniformly cooling a drawn optical fiber (having temperature more than 2000°C) around its surface. When deployed in a running optical fiber draw tower set-up (i.e. a draw tower in which optical fiber is being continuously drawn), the diffuser 100 was placed in a manner such that the drawn optical fiber passed through the central axis 102. Finally, a cooling fluid (such as cooled Nitrogen, or Helium) from a reservoir was pumped into the hollow annular tube 104 through inlet pipes 106. Internal pressure built-up within the diffuser 100 due to continuous inflow of the cooling fluid through the inlet pipes forced ejection of cooling fluid through the fluid ejection apertures 108. While passing through the diffuser 100, the drawn fiber, which was at a temperature of more than 2000 °C got uniformly cooled across its entire surface by jets of cooling fluid ejected from fluid ejection apertures 108 in a manner as described above.
[0051] Optical fiber which passed from the diffuser 100 installed in the optical fiber draw tower performed better at physical strength test (such as proof test and fatigue test) and optical signal attenuation tests.
[0052] Numerous suitable variations in the embodiment described above would be obvious for a person skilled in the art. It should be noted that all such embodiments which would result from such variations are also fully covered within the scope of the invention. Hence, the scope of the present invention is also not limited itself by the embodiment described above. For example, a fluid diffuser, which is in accordance with the present invention, can be used to eject (or diffuse out) any type of fluid i.e. either a gas, a liquid or a mixture of gases from its fluid ejection apertures. The fluid could be either a liquid (for example, water) or a gas (such as helium, argon, nitrogen) or a mixture of gases, (such as air). The scope of the present invention also does not gets limited by the type of fluid used. Depending on the desired benefits of using a suitable liquid or gas or a mixture of gas, the embodiments of the present invention may be used with any fluid type.
[0053] Next, Apart from diffusing a cooling fluid for cooling a longitudinal body as described earlier, the embodiments of diffuser of the present invention may also be used for ejecting a heated fluid for heating a longitudinal body passing through its central axis. It is to be understood that regardless of the fact that whether the fluid diffuser provided by the present invention is being used for cooling or heating a longitudinal body passing through its central axis, all embodiments of the fluid diffuser which are in accordance with the present invention, are fully covered under scope of the present invention. The scope of the present invention does not gets limited by the function of fluid which flows out through the diffuser. In other words, all embodiments of the present invention, regardless of the temperature of fluid being diffused / ejected by them are fully covered within the scope of the present invention. In other words, scope of the present invention does not gets limited by temperature of fluid being ejected by the fluid ejection apertures of any of its embodiments. All embodiments of the fluid diffuser, which are in accordance with the present invention and which are fully covered within its scope, may include variations in the function or the purpose of fluid being ejected from the fluid ejection apertures.
[0054] It should be noted that scope of the present invention also does not gets limited by the count of the inlet apertures (and inlet pipers) and the count of ejections apertures, provided that the count of inlet apertures (and inlet pipers) and the count of ejections apertures should be ≥2. All embodiments of the fluid diffuser, which are in accordance with the present invention and which are fully covered within its scope, may include variations in the count of the inlet apertures (and inlet pipers) and the count of fluid ejections apertures.
[0055] Scope of present invention also does not gets limited by the application of the embodiments of fluid diffuser. For example, though the embodiment of the fluid diffuser as described above is being deployed in an optical fiber draw tower for cooling drawn optical fibers, it is to be understood that described diffuser embodiment can also be used to cool a heated metallic wire (such as copper or Aluminum wire or strands) in a metallic wire drawing facility, or for cooling a polymer/plastic fiber in a polymer/plastic fiber drawing facility. Hence, it is to be noted that the diffuser proposed by the present invention has applications in multiple fields.
[0056] It should be noted that while a preferred material for the hollow annular tube and the hollow inlet pipes of the fluid diffuser is a metal, fluid diffusers, in accordance with the present invention can also be made from other suitable materials including polymers, ceramics, and composite materials. Embodiments of the fluid diffuser, which are in accordance with the present invention and which are fully covered within its scope, may include variations in the material from which the hollow annular tube and the hollow inlet pipes of the fluid diffuser are made.
[0057] It would be obvious for a person skilled in the art to make/suggest/propose many more embodiments of the invention with minor or obvious modifications. It should be noted that all embodiments of the diffuser which have essential features of the invention incorporated within themselves are fully covered within the scope of the present invention.
[0058] It is to be understood that the foregoing description is intended to illustrate and not limit the scope of the invention. Accordingly, the embodiment of the invention described above is not intended to limit the invention. Although described in the context of above embodiment, other embodiments of the invention which would be apparent to those skilled in the art are very well covered within the scope of the invention. Thus, while the invention has been particularly shown and described with respect to the above mentioned embodiment, it will be understood by those skilled in the art that certain modifications or changes may be made therein without departing from the scope and spirit of the invention.