[0001] The present disclosure relates to the field of optical fibre draw furnace
and, in particular, relates to an apparatus for sealing top of the optical fibre draw
furnace.
10
BACKGROUND
[0002] With the advancement in science and technology, various modern
technologies are being employed for communication purposes. One of the most
15 important modern communication technologies is optical fibre communication
technology using a variety of optical fibre cables. In addition, the optical fibre cables
are widely used for communication to meet the increasing demands. Further,
manufacturing of optical fibres for the optical fibre cables becomes essential.
Furthermore, the optical fibres are manufactured from a quartz-based optical fibre
20 glass preform moving downward from an upper opening of a drawing furnace.
Moreover, the optical fibre glass preform enters the drawing furnace. Also, diameter
of the optical fibre glass preform decreases using heating and melting of distal end of
the optical fibre glass preform. Also, the optical fibres are drawn from a lower
opening of the drawing furnace. Also, atmospheric air is prevented from entering
25 inside the drawing furnace. In addition, positive pressure is maintained inside the
drawing furnace. Further, the drawing furnace should remain airtight. Also, the
airtightness is maintained by a sealing gap between the upper opening of the drawing
furnace and the optical fibre glass preform. Also, the atmospheric air and amount of
inert gases affect life of the drawing furnace. Also, the inert gases include nitrogen
30 gas, argon gas, helium gas, and the like. Hence, a seal is utilized to close gap
between the upper opening of the drawing furnace and the optical fibre glass preform.
3/19
5 [0003] Conventionally, graphite felt is utilized to seal the drawing furnace. In
addition, conventional seal is positioned near to heat chamber of the drawing furnace.
Further, the conventional seal deteriorates when small amount of atmospheric air
enters the drawing furnace. The conventional seal is inefficient to handle high
drawing speed and heavy optical fibre glass preform. The conventional seal affects
10 drawing parameters of the drawing furnace when deterioration starts. Also, the
conventional seal affects optical parameters of the optical fibres manufactured in the
drawing furnace when deterioration starts. The conventional seal is continuously
exposed to high temperature of the drawing furnace. Also, the conventional seal
affects insertion of the inert gases in the drawing furnace when deterioration starts.
15 Some of the prior art references are given below:
[0004] US20190292087A1 discloses an optical fiber preform manufacturing
apparatus comprising a seal member. The seal member is attached to a flange portion
formed in an open portion of a reaction chamber into which a burner is inserted. In
20 addition, the optical fiber preform manufacturing apparatus has the burner inserted
into the reaction chamber through the open portion of the seal member to generate
and deposit glass microparticles.
[0005] EP1159229A1 discloses an apparatus and method for sealing the
25 bottom of an optical waveguide draw furnace. The apparatus includes an assembly
constructed and arranged to mate with bottom of the optical waveguide draw furnace
to form a seal. In addition, the apparatus includes a leak detection system
communicating with the assembly to determine if the seal leaks. Further, the
assembly includes a covering plate having a top surface. Furthermore, the top surface
30 of the covering plate of the optical waveguide draw furnace includes a first gasket
and a second gasket radially spaced from the first gasket.
[0006] EP1159228A1 discloses an apparatus and method for sealing top of an
optical waveguide fiber draw furnace. The apparatus includes an assembly
4/19
5 constructed and arranged to removably cover the top of the optical waveguide fiber
draw furnace and mate with a downfeed handle. In addition, the assembly
comprising an elongated sleeve having a base and defining a chamber. Further, the
assembly includes an inert gas supply communicating with the assembly to
selectively deliver inert gas into the chamber of the optical waveguide fiber draw
10 furnace. Furthermore, the assembly includes a sealing mechanism supported by the
elongated sleeve to mate with the downfeed handle for cooperating with the top of the
optical waveguide fiber draw furnace to prevent air from entering the optical
waveguide fiber draw furnace.
15 [0007] US10487001B2 discloses a seal structure of an optical fiber drawing
furnace. The seal structure seals a gap between an upper end opening of the optical
fiber drawing furnace.
[0008] While the prior arts cover various approaches to seal a gap between
20 the upper opening of the drawing furnace and the optical fibre glass preform, there
are no significant considerations to position the seal at a tolerable distance from the
heat chamber of the drawing furnace. In light of the above-stated discussion, there is
a need to overcome the above stated disadvantages.
25 OBJECT OF THE DISCLOSURE
[0009] A primary object of the present disclosure is to provide an apparatus for
sealing top of the optical fibre draw furnace.
30 [0010] Another object of the present disclosure is to provide adjustable
apparatus for sealing top of the optical fibre draw furnace.
5/19
5 [0011] Yet another object of the present disclosure is to provide the optical fibre
draw furnace that improves properties of glass preform.
SUMMARY
10 [0012] In an aspect, the present disclosure provides an optical fibre draw
furnace. The optical fibre draw furnace includes a hollow cylindrical structure. In
addition, the optical fibre draw furnace includes one or more heating elements.
Further, the optical fibre draw furnace includes a sealing felt. The hollow cylindrical
structure includes a glass preform positioned inside the hollow cylindrical structure.
15 The glass preform has diameter greater than 50 millimetres. The one or more heating
elements are situated at periphery of the hollow cylindrical structure. The one or
more heating elements are utilized for melting the glass preform. The sealing felt is
positioned above the optical fibre draw furnace. The sealing felt is positioned at a
pre-defined distance above the optical fibre draw furnace. The sealing felt includes a
20 first opening. The sealing felt includes a second opening. The first opening is
utilized to hold the glass preform. The first opening allows passing of the glass
preform inside the optical fibre draw furnace. The second opening facilitates in input
of gas inside the optical fibre draw furnace. The second opening facilitates in
avoiding deterioration of the optical fibre draw furnace. The optical fibre draw
25 furnace supports high speed drawing of the glass preform at drawing speed in range
of 2500 metre per second to 3500 metre per second. The position of the sealing felt
in the optical fibre draw preform facilitates in improving properties of the optical
fibre.
30 [0013] In an embodiment of the present disclosure, the sealing felt is retrofitted
on standard optical fibre draw furnace without requirement of additional adjustments.
6/19
5 [0014] In an embodiment of the present disclosure, the pre-defined distance is in
range of 10 centimetres to 20 centimetres.
[0015] In an embodiment of the present disclosure, the sealing felt supports the
glass preform with diameter in range of 100 millimetres to 150 millimetres.
10
[0016] In an embodiment of the present disclosure, the gas includes at least one
of nitrogen, helium, and argon.
[0017] In an embodiment of the present disclosure, the optical fibre draw
15 furnace facilitates in reduction of scrap, wherein the scrap comprising at least one of
optical rejection, draw rejection, and PT (prof testing of optical fibre) rejection.
STATEMENT OF THE DISCLOSURE
20 [0018] The present disclosure provides an optical fibre draw furnace. The
optical fibre draw furnace includes a hollow cylindrical structure. In addition, the
optical fibre draw furnace includes one or more heating elements. Further, the optical
fibre draw furnace includes a sealing felt. The hollow cylindrical structure includes a
glass preform positioned inside the hollow cylindrical structure. The glass preform
25 has diameter greater than 50 millimetres. The one or more heating elements are
situated at periphery of the hollow cylindrical structure. The one or more heating
elements are utilized for melting the glass preform. The sealing felt is positioned
above the optical fibre draw furnace. The sealing felt is positioned at a pre-defined
distance above the optical fibre draw furnace. The sealing felt includes a first
30 opening. The sealing felt includes a second opening. The first opening is utilized to
hold the glass preform. The first opening allows passing of the glass preform inside
the optical fibre draw furnace. The second opening facilitates in input of gas inside
the optical fibre draw furnace. The second opening facilitates in avoiding
7/19
5 deterioration of the optical fibre draw furnace. The optical fibre draw furnace
supports high speed drawing of the glass preform at drawing speed in range of 2500
metre per second to 3500 metre per second. The position of the sealing felt in the
optical fibre draw preform facilitates in improving properties of the optical fibre.
10 BRIEF DESCRIPTION OF FIGURES
[0019] Having thus described the disclosure in general terms, reference will now
be made to the accompanying figures, wherein:
15 [0020] FIG. 1 illustrates a cross sectional view of an optical fibre draw furnace,
in accordance with various embodiments of the present disclosure;
[0021] FIG. 2 illustrates a first chart of scrap percentage in the optical fibre
draw furnace, in accordance with an embodiment of the present disclosure;
20
[0022] FIG. 3 illustrates a second chart of drawing breaks in the optical fibre
draw furnace, in accordance with an embodiment of the present disclosure; and
[0023] FIG. 4 illustrates a third chart of PT breaks in the optical fibre draw
25 furnace, in accordance with an embodiment of the present disclosure.
[0024] It should be noted that the accompanying figures are intended to present
illustrations of few exemplary embodiments of the present disclosure. These figures
are not intended to limit the scope of the present disclosure. It should also be noted
30 that accompanying figures are not necessarily drawn to scale.
8/19
5 DETAILED DESCRIPTION
[0025] Reference will now be made in detail to selected embodiments of the
present disclosure in conjunction with accompanying figures. The embodiments
described herein are not intended to limit the scope of the disclosure, and the present
10 disclosure should not be construed as limited to the embodiments described. This
disclosure may be embodied in different forms without departing from the scope and
spirit of the disclosure. It should be understood that the accompanying figures are
intended and provided to illustrate embodiments of the disclosure described below
and are not necessarily drawn to scale. In the drawings, like numbers refer to like
15 elements throughout, and thicknesses and dimensions of some components may be
exaggerated for providing better clarity and ease of understanding.
[0026] It should be noted that the terms "first", "second", and the like, herein do
not denote any order, ranking, quantity, or importance, but rather are used to
20 distinguish one element from another. Further, the terms "a" and "an" herein do not
denote a limitation of quantity, but rather denote the presence of at least one of the
referenced item.
[0027] FIG. 1 illustrates a cross sectional view of an optical fibre draw furnace
25 100, in accordance with various embodiments of the present disclosure. The optical
fibre draw furnace 100 includes a hollow cylindrical structure 102, a glass preform
104, one or more heating elements 106, and a sealing felt 108. In addition, the optical
fibre draw furnace 100 includes a heat chamber 114, a lower opening 116, an optical
fibre 118, a pyrometer 120, and an insulation zone 122.
30
[0028] The optical fibre draw furnace 100 is an induction furnace used for
heating the glass preform 104 in order to draw the optical fibre 118 therefrom. The
sealing felt 108 includes a first opening 110 and a second opening 112. The optical
9/19
5 fibre draw furnace 100 includes the glass preform 104. The glass preform 104 is a
piece of glass that facilitates drawing of the optical fibre 118. In addition, the glass
preform 104 is a solid glass rod that is used to manufacture the optical fibre 118. In
addition, the optical fibre 118 is a flexible, transparent fibre made by drawing glass or
plastic to a diameter slightly thicker than that of a human hair. Further, the optical
10 fibre 118 refers to medium or technology used for transmission of information as
light pulses over large distances.
[0029] The hollow cylindrical structure 102 includes the glass preform 104. The
hollow cylindrical structure 102 is utilized to cover the glass preform 104 during
15 drawing of the optical fibre 118 from the glass preform 104. The hollow cylindrical
structure 102 protects the glass preform 104 from external environment during
drawing of the optical fibre 118 from the glass preform 104. The glass preform 104
has diameter greater than about 50 millimetres. In an embodiment of the present
disclosure, the diameter of the glass preform 104 may vary.
20
[0030] The optical fibre draw furnace 100 includes the one or more heating
elements 106. The one or more heating elements 106 are situated at periphery of the
hollow cylindrical structure 102. The one or more heating elements 106 provide heat
to the hollow cylindrical structure 102 of the optical fibre draw furnace 100. The one
25 or more heating elements 106 are utilized to melt the glass preform 104 to
manufacture the optical fibre 118 during drawing.
[0031] The one or more heating elements 106 surround the hollow cylindrical
structure 102. In an embodiment of the present disclosure, the one or more heating
30 elements 106 are cylindrical in shape. In another embodiment of the present
disclosure, shape of the one or more heating elements may vary.
10/19
5 [0032] The optical fibre draw furnace 100 includes the sealing felt 108. The
sealing felt 108 is positioned above the optical fibre draw furnace 100. The sealing
felt 108 seals a gap above the optical fibre draw furnace 100. The sealing felt 108 is
positioned at a pre-defined distance above the optical fibre draw furnace 100. The
pre-defined distance is in range of 10 centimetres to 20 centimetres. In an
10 embodiment of the present disclosure, range of the pre-defined distance may vary.
[0033] In an embodiment of the present disclosure, the sealing felt 108 supports
the glass preform 104 with diameter in range of 100 millimetres to 150 millimetres.
In another embodiment of the present disclosure, the sealing felt 108 supports the
15 glass preform 104 with any other diameter of the like.
[0034] The sealing felt 108 includes the first opening 110. The first opening
110 is utilized to hold the glass preform 104. The first opening 110 allows passing of
the glass preform 104 inside the optical fibre draw furnace 100 through the sealing
20 felt 108. The sealing felt 108 includes the second opening 112. The second opening
112 facilitates in input of gas inside the optical fibre draw furnace 100. In addition,
the second opening 112 facilitates to avoid deterioration of the optical fibre draw
furnace 100. The gas includes at least one of nitrogen, helium, and argon. In an
embodiment of the present disclosure, the gas may vary.
25
[0035] In an embodiment of the present disclosure, the sealing felt 108 is
cylindrical in shape. In another embodiment of the present disclosure, shape of the
sealing felt 108 may vary. In an embodiment of the present disclosure, the optical
fibre draw furnace 100 supports high speed drawing of the glass preform 104 at
30 drawing speed in range of 2500 metre per second to 3500 metre per second. In
another embodiment of the present disclosure, speed of drawing of the glass preform
104 may vary. The position of the sealing felt 108 in the optical fibre draw furnace
100 facilitates to improve properties of the optical fibre 118.
11/19
5
[0036] Proof testing or PT is a common technique to ensure minimum strength
of optical fibre 118 and eliminate the flaws whose sizes are dependent on the stress
applied during proof testing. In proof testing, predetermined load is applied on optical
fibre 118 by tensile loading. The optical fibre breaks at the weak points and the weak
10 parts are eliminated from the optical fibre 118. The proof test will guarantee a
minimum strength level (i.e. above proof testing stress) of the optical fibre 118 and
lifetime.
[0037] In an embodiment of the present disclosure, draw parameters include but
15 may not be limited to stress, strain rate, temperature, thickness, co-efficient of
friction, drawing speed and holding force. Stress may be termed as non-specific
response of the optical fibre 118 to any demand for change. Strain rate may be
termed as change in deformation of the optical fibre 118 with respect to time.
Temperature is degree or intensity of heat in any substance or object. Further,
20 thickness is measurement of distance though an object. Furthermore, co-efficient of
friction is a dimensionless number that is defined as a ratio between friction force and
normal force. The drawing speed depends on the glass preform 104, type of the
optical fibre 118 and the optical fibre draw furnace 100.
25 [0038] In an embodiment of the present disclosure, the optical parameters
include but may not be limited to attenuation, dispersion, mode-field diameter, and
cut-off wavelength. Attenuation refers to rate at which signal light decreases in
intensity inside the optical fibre 118. Dispersion refers to spreading of light pulse as
it travels down the length of the optical fibre 118. Mode-field diameter is an
30 expression of distribution of irradiance, i.e., optical power per unit area, across the
end face of the optical fibre 118. Cut-off wavelength is minimum wavelength in
which the optical fibre 118 acts as single mode optical fibre. Single mode optical
fibre is an optical fibre designed to carry only a single mode of light.
12/19
5 [0039] The optical fibre draw furnace 100 includes the heat chamber 114. The
heat chamber 114 continuously provides heat to the glass preform 104. The heat
chamber 114 provides heat to the glass preform 104 to partially melt the glass
preform 104. The lower opening 116 is opening that allows the optical fibre 118 to
pass after completion of the drawing process.
10 [0040] The optical fibre draw furnace 100 includes the pyrometer 120. The
pyrometer 120 is a type of remote sensing thermometer that is used to measure
temperature. The pyrometer 120 is installed in the optical fibre draw furnace 100 to
measure temperature. The optical fibre draw furnace 100 includes the insulation zone
122.
15
[0041] The insulation zone 122 is utilized to retain heat inside the optical fibre
draw furnace 100. The insulation zone 122 is made up of one or more insulators.
The insulators are materials that inhibit flow of electric current. In an example, the
insulators include fiberglass, foam insulation, thermal flask, Styrofoam, and the like.
20 The insulation zone 122 retains heat inside the optical fibre draw furnace 100 to
quickly perform drawing of the optical fibre 118.
[0042] In an embodiment of the present disclosure, the sealing felt 108 is
retrofitted on standard optical fibre draw furnace 100 without requirement of
25 additional adjustments. In an embodiment of the present disclosure, the sealing felt
108 supports the glass preform 104 with diameter in range of 100 millimetres to 150
millimetres. However, diameter is not limited to above mentioned diameter.
[0043] In an embodiment of the present disclosure, the optical fibre draw
30 furnace 100 facilitates in reduction of scrap. The scrap includes at least one of optical
rejection, draw rejection, and pt rejection.
13/19
5 [0044] FIG. 2 illustrates a first chart 200 of scrap percentage in the optical fibre
draw furnace 100, in accordance with an embodiment of the present disclosure. In an
embodiment of the present disclosure, the first chart 200 is a shewhart individuals
control chart. In another embodiment of the present disclosure, the first chart 200 is
any suitable type of control chart.
10
[0045] In an embodiment of the present disclosure, the first chart 200 enables
monitoring of scrap percentage per observation. In addition, the first chart 200
demonstrates scrap reduction per observation. In an embodiment of the present
disclosure, the first chart 200 of scrap percentage has an upper control limit of about
15 14.16. In another embodiment of the present disclosure, the upper control limit of
scrap percentage illustrated in the first chart 200 may vary.
[0046] In addition, the first chart 200 represents an arithmetic mean of scrap
percentage as X̄. In an embodiment of the present disclosure, the first chart 200 of
20 scrap percentage has the arithmetic mean X̄ of about 12.24. In another embodiment
of the present disclosure, the arithmetic mean X̄ of scrap percentage illustrated in the
first chart 200 may vary. In an embodiment of the present disclosure, the first chart
200 of scrap percentage has a lower control limit of about 10.32. In another
embodiment of the present disclosure, the lower control limit of scrap percentage
25 illustrated in the first chart 200 may vary.
[0047] FIG. 3 illustrates a second chart 300 of drawing breaks in the optical
fibre draw furnace 100, in accordance with an embodiment of the present disclosure.
In an embodiment of the present disclosure, the second chart 300 is the shewhart
30 individuals control chart. In another embodiment of the present disclosure, the
second chart 300 is any suitable type of control chart.
[0048] In an embodiment of the present disclosure, the second chart 300 enables
monitoring of drawing breaks per 10k kms or per 10,000 km length of optical fibre
14/19
5 118 observation. In addition, the second chart 300 demonstrates drawing breaks per
10k kms or per 10,000 km length of optical fibre 118. In an embodiment of the
present disclosure, the second chart 300 of drawing breaks per 10k kms or per 10,000
km length of optical fibre 118 has an upper control limit of about 1.457. In another
embodiment of the present disclosure, the upper control limit of drawing breaks per
10 10k kms or per 10,000 km length of optical fibre 118 illustrated in the second chart
300 may vary.
[0049] In addition, the second chart 300 represents an arithmetic mean of
drawing breaks per 10k kms or per 10,000 km length of optical fibre 118 as X̄. In an
15 embodiment of the present disclosure, the second chart 300 of drawing breaks per
10k kms or per 10,000 km length of optical fibre 118 has the arithmetic mean X̄ of
about 1.058. In another embodiment of the present disclosure, the arithmetic mean X̄
of drawing breaks per 10k kms or per 10,000 km length of optical fibre 118
illustrated in the second chart 300 may vary. In an embodiment of the present
20 disclosure, the second chart 300 of drawing breaks per 10k kms or per 10,000 km
length of optical fibre 118 has a lower control limit of about 0.659. In another
embodiment of the present disclosure, the lower control limit of drawing breaks per
10k illustrated in the second chart 300 may vary.
25 [0050] FIG. 4 illustrates a third chart 400 of PT breaks in the optical fibre draw
furnace 100, in accordance with an embodiment of the present disclosure. In an
embodiment of the present disclosure, the third chart 400 is the shewhart individuals
control chart. In another embodiment of the present disclosure, the third chart 400 is
any suitable type of control chart.
30
[0051] In an embodiment of the present disclosure, the third chart 400 enables
monitoring of prof testing or PT breaks per km length of optical fibre 118
observation. In addition, PT breaks corresponds to parity time breaks. Further, the
third chart 400 demonstrates PT breaks per km. In an embodiment of the present
15/19
5 disclosure, the third chart 400 of PT breaks per km has an upper control limit of about
4.630. In another embodiment of the present disclosure, the upper control limit of PT
breaks per k illustrated in the third chart 400 may vary.
[0052] In addition, the third chart 400 represents an arithmetic mean of PT
breaks per k as X̄ 10 . In an embodiment of the present disclosure, the third chart 400 of
PT breaks per km has the arithmetic mean X̄ of about 3.807. In another embodiment
of the present disclosure, the arithmetic mean X̄ of PT breaks per km illustrated in the
third chart 400 may vary. In an embodiment of the present disclosure, the third chart
400 of PT breaks per km has a lower control limit of about 2.985. In another
15 embodiment of the present disclosure, the lower control limit of PT breaks per km
illustrated in the third chart 400 may vary.
[0053] In an embodiment of the present disclosure, the optical fibre draw
furnace 100 that includes the sealing felt 108 facilitates in reduction of scrap. The
20 positioning of sealing felt 108 with a pre-defined distance above the optical fibre
draw furnace 100 in the range of 10 centimetres to 20 centimetres reduces scrap
including optical rejection scrap, draw rejection scrap, and PT rejection scrap.
25 [0054] The foregoing descriptions of specific embodiments of the present
technology have been presented for purposes of illustration and description. They are
not intended to be exhaustive or to limit the present technology to the precise forms
disclosed, and obviously many modifications and variations are possible in light of
the above teaching. The embodiments were chosen and described in order to best
30 explain the principles of the present technology and its practical application, to
thereby enable others skilled in the art to best utilize the present technology and
various embodiments with various modifications as are suited to the particular use
contemplated. It is understood that various omissions and substitutions of equivalents
are contemplated as circumstance may suggest or render expedient, but such are
16/19
5 intended to cover the application or implementation without departing from the spirit
or scope of the claims of the present technology.
[0055] While several possible embodiments of the invention have been
described above and illustrated in some cases, it should be interpreted and understood
10 as to have been presented only by way of illustration and example, but not by
limitation. Thus, the breadth and scope of a preferred embodiment should not be
limited by any of the above-described exemplary embodiments.

What is claimed is:

1. An optical fibre draw furnace (100) comprising:
10 a hollow cylindrical structure (102), wherein the hollow cylindrical structure
(102) comprising a glass preform (104) positioned inside the hollow cylindrical
structure (102), wherein the glass preform (104) has diameter greater than 50
millimetres;
15 one or more heating elements (106), wherein the one or more heating
elements (106) are situated at a periphery of the hollow cylindrical structure (102),
wherein the one or more heating elements (106) are utilized for melting the glass
preform (104); and
20 a sealing felt (108), wherein the sealing felt (108) is positioned on top of the
optical fibre draw furnace (100), wherein the sealing felt (108) is positioned at a predefined distance above the optical fibre draw furnace (100), wherein the pre-defined
distance is in a range of about 14-20 cm above the optical fibre draw furnace (100),
wherein the sealing felt (108) comprising:
25
a first opening (110), wherein the first opening (110) is utilized to hold the
glass preform (104), wherein the first opening (110) allows the glass preform (104) to
be inserted in the optical fibre draw furnace (100); and
30 a second opening (112), wherein the second opening (112) facilitates input of
plurality of gases inside the optical fibre draw furnace (100), wherein the second
opening (112) facilitates in avoiding deterioration of the optical fibre draw furnace
(100),
18/19
5
wherein the optical fibre draw furnace (100) supports high speed drawing of
the glass preform (104) at drawing speed in range of about 2500 metre per second to
3500 metre per second, wherein position of the sealing felt (108) in the optical fibre
draw preform facilitates in improving properties of the glass preform (104).
10
2. The optical fibre draw furnace (100) as recited in claim 1, wherein the sealing
felt (108) is retrofitted on standard optical fibre draw furnace (100) without additional
adjustments.
15 3. The optical fibre draw furnace (100) as recited in claim 1, wherein the predefined distance is in range of 10 centimetres to 20 centimetres above the optical
fibre draw furnace (100).
4. The optical fibre draw furnace (100) as recited in claim 1, wherein the sealing
20 felt (108) supports the glass preform (104) with diameter in range of about 100
millimetres to 150 millimetres.
5. The optical fibre draw furnace (100) as recited in claim 1, wherein the gas
comprising at least one of nitrogen, helium, and argon.
25
6. The optical fibre draw furnace (100) as recited in claim 1, wherein the optical
fibre draw furnace (100) facilitates in reduction of scrap, wherein the scrap
comprising at least one of optical rejection, draw rejection, and prof testing rejection.