U.S. patent application number 16/849956 was filed with the patent office on 2021-02-18 for system and method for performing separation and dehydroxylation of fumed silica soot particles.
The applicant listed for this patent is Sterlite Technologies Limited. Invention is credited to Shivi Dixit, Sandeep Gaikwad, Badri Gomatam.
Application Number | 20210047189 16/849956 |
Document ID | / |
Family ID | 1000005079523 |
Filed Date | 2021-02-18 |
![](/patent/app/20210047189/US20210047189A1-20210218-D00000.png)
![](/patent/app/20210047189/US20210047189A1-20210218-D00001.png)
![](/patent/app/20210047189/US20210047189A1-20210218-D00002.png)
![](/patent/app/20210047189/US20210047189A1-20210218-D00003.png)
![](/patent/app/20210047189/US20210047189A1-20210218-D00004.png)
![](/patent/app/20210047189/US20210047189A1-20210218-D00005.png)
![](/patent/app/20210047189/US20210047189A1-20210218-M00001.png)
![](/patent/app/20210047189/US20210047189A1-20210218-M00002.png)
United States Patent
Application |
20210047189 |
Kind Code |
A1 |
Gaikwad; Sandeep ; et
al. |
February 18, 2021 |
SYSTEM AND METHOD FOR PERFORMING SEPARATION AND DEHYDROXYLATION OF
FUMED SILICA SOOT PARTICLES
Abstract
The present disclosure provides a separator system for
performing separation and dehydroxylation of fumed silica
particles. The separator system includes a first inlet, a second
inlet, a main body, a first outlet and a second outlet. The first
inlet collects a primary feed of fumed silica particles from a
gaseous stream into a double entry cyclone. The second inlet
collects a secondary feed of chlorine gas into the double entry
cyclone. The main body of the double entry cyclone is utilized in
treating the primary feed and the secondary feed along with heat
inside the double entry cyclone. Furthermore, the first outlet is
utilized for releasing the dehydrated fumed silica particles and
the second outlet is utilized for releasing the water molecules and
other gases.
Inventors: |
Gaikwad; Sandeep;
(Aurangabad, IN) ; Dixit; Shivi; (Aurangabad,
IN) ; Gomatam; Badri; (Aurangabad, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sterlite Technologies Limited |
Aurangabad |
|
IN |
|
|
Family ID: |
1000005079523 |
Appl. No.: |
16/849956 |
Filed: |
April 15, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 8/0055 20130101;
B01J 8/1827 20130101; B04C 5/02 20130101; B04C 5/20 20130101; C01B
33/18 20130101; B01J 2208/00769 20130101; B01D 45/16 20130101 |
International
Class: |
C01B 33/18 20060101
C01B033/18; B01J 8/18 20060101 B01J008/18; B01J 8/00 20060101
B01J008/00; B01D 45/16 20060101 B01D045/16; B04C 5/02 20060101
B04C005/02; B04C 5/20 20060101 B04C005/20 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 13, 2019 |
IN |
201921032781 |
Claims
1. A method for performing separation of fumed silica particles,
the method comprising: collecting a primary feed of fumed silica
particles from a gaseous stream, wherein the primary feed of fumed
silica particles is collected in a fluidized state; collecting a
secondary feed of chlorine gas, wherein the secondary feed of
chlorine gas is collected for performing separation of the
fluidized fumed silica particles; treating the primary feed of the
fumed silica particles and the secondary feed of chlorine gas along
with heat; and releasing the dehydrated fumed silica particles from
a first outlet, whereby separating the fumed silica particles.
2. The method as recited in claim 1, wherein the primary feed of
fumed silica particles from a gaseous stream is collected into a
double entry cyclone from a first inlet.
3. The method as recited in claim 1, wherein collecting the
secondary feed of chlorine gas into the double entry cyclone from a
second inlet.
4. The method as recited in claim 1 further comprising, after
performing separation of the fumed silica particles, releasing
water molecules and gases from a second outlet.
5. A separator system for performing separation and dehydroxylation
of fumed silica particles, the separator system comprising: a first
inlet, wherein the first inlet is utilized for collecting a primary
feed of fumed silica particles from a gaseous stream into a double
entry cyclone, wherein the primary feed of fumed silica particles
is collected in a fluidized state; a second inlet, wherein the
second inlet is utilized for collecting a secondary feed of
chlorine gas into the double entry cyclone, wherein the secondary
feed of chlorine gas is collected for performing dehydroxylation of
the fluidized fumed silica particles; a main body of the double
entry cyclone, wherein the main body of the double entry cyclone is
utilized in treating the primary feed of the fumed silica particles
and the secondary feed of chlorine gas along with heat inside the
double entry cyclone; a first outlet, wherein the first outlet is
utilized for releasing the dehydrated fumed silica particles; and a
second outlet, wherein the second outlet is utilized for releasing
the water molecules and other gases after performing separation and
dehydroxylation of the fumed silica particles.
6. The separator system as recited in claim 5, wherein the vortex
formation imparts centrifugal force on the fluidized fumed silica
particles and the separation and dehydroxylation of the fumed
silica particles happens for releasing dehydrated fumed silica
particles and water molecules.
7. The separator system as recited in claim 5, wherein the fumed
silica particles undergoes dehydroxylation for removing
physiosorbed water molecules and chemisorbed water molecules,
wherein the chemisorbed water molecules are removed after removal
of the physiosorbed water molecules, wherein the physiosorbed water
molecules are removed at temperature of about 200 degrees Celsius,
wherein the chemisorbed water molecules remaining after temperature
of 200 degrees Celsius is in range of about 30 parts per million to
50 parts per million.
8. The separator system as recited in claim 5, wherein the
separator system performs dehydroxylation of isolated SiOH groups,
geminal SiOH groups and vicinal SiOH groups, wherein the
dehydroxylation of isolated SiOH groups, geminal SiOH groups and
vicinal SiOH groups is defined by rate law dCdt=? k [c]n at
temperature in range of about 320 degree Celsius to 1200 degree
Celsius.
9. The separator system as recited in claim 5, wherein the fumed
silica particles undergoes separation and dehydroxylation in a time
period, wherein the time period for separation and dehydroxylation
of the fumed silica particles depends upon one or more factors.
10. A method for performing separation of fumed silica particles,
the method comprising: collecting, a primary feed of fumed silica
particles from a gaseous stream into a double entry cyclone from a
first inlet, wherein the primary feed of fumed silica particles is
collected in a fluidized state; collecting, a secondary feed of
chlorine gas into the double entry cyclone from a second inlet,
wherein the secondary feed of chlorine gas is collected for
performing separation of the fluidized fumed silica particles;
treating, the primary feed of the fumed silica particles and the
secondary feed of chlorine gas along with heat inside a main body
of the double entry cyclone; releasing, the dehydrated fumed silica
particles from a first outlet; and releasing, the water molecules
and other gases after performing separation of the fumed silica
particles from a second outlet.
11. The method as recited in claim 10, further comprising,
performing dehydroxylation of the fluidized fumed silica particles
in a chamber, wherein the dehydroxylation is performed after
performing separation of the fumed silica particles in the double
entry cyclone, wherein the chamber is surrounded by one or more
induction furnaces.
12. The method as recited in claim 10, further comprising,
performing dehydroxylation of the fluidized fumed silica particles
in one or more chambers, wherein the dehydroxylation is performed
after performing separation of the fumed silica particles in the
double entry cyclone, wherein the one or more chambers are
surrounded by one or more induction furnaces.
13. The method as recited in claim 10, further comprising,
performing compaction of the fluidized fumed silica particles using
a punch and a die apparatus, wherein the compaction is performed
after performing separation of the fumed silica particles in the
double entry cyclone, wherein the compaction is performed for
performing dehydroxylation of compacted fumed silica particles.
14.
Description
TECHNICAL FIELD
[0001] The present invention relates to the field of manufacturing
of optical fibres and, in particular, relates to a system and
method for performing separation and dehydroxylation of fumed
silica particles. The present application is based on, and claims
priority from Indian application 201921032781 filed on 13.sup.th
Aug. 2019, the disclosure of which is hereby incorporated by
reference herein.
BACKGROUND
[0002] Over the last few years, there has been an exponential rise
in the manufacturing of optical fibres due to an overgrowing demand
of the optical fibres. The manufacturing of optical fibres has two
major stages. The first stage involves the manufacturing of optical
fibre preforms and the second stage involves drawing the optical
fibres from the optical fibre preforms. In general, the quality of
optical fibres depends on conditions of manufacturing. So, a lot of
attention is paid towards the manufacturing of the optical fibre
preforms with good characteristic. These optical fibre preforms
include an inner glass core surrounded by a glass cladding having a
lower index of refraction than the inner glass core. The
dehydration of silica is a requisite in optical fibre manufacturing
to remove OH from optical fibre preform. Conventionally, the silica
particles obtained after processes such as OVD is geometry and
density specific. This poses a challenge for performing dehydration
of the silica particles in the preform requires continuous
processing by coming in contact with reagent and getting treated
with heat. The improper processing of the f silica particles may
affect quality of the optical fibre preform.
[0003] In light of the above stated discussion, there is a need for
a system and method for obtaining dehydrated silica particles.
SUMMARY
[0004] The present disclosure provides a separator system for
performing separation and dehydroxylation of fumed silica
particles. The separator system includes a first inlet. The
separator system includes a second inlet. In addition, the
separator system includes a main body of a double entry cyclone.
Further, the separator system includes a first outlet. Furthermore,
the separator system includes a second outlet. The first inlet is
utilized for collecting a primary feed of fumed silica particles
from a gaseous stream into a double entry cyclone. The primary feed
of fumed silica particles is collected in a fluidized (free
flowing) state. The second inlet is utilized for collecting a
secondary feed of chlorine gas into the double entry cyclone. The
secondary feed of chlorine gas is collected for performing
dehydroxylation of the fluidized (free flowing) fumed silica
particles. The main body of the double entry cyclone is utilized in
treating the primary feed of the silica particles and the secondary
feed of chlorine gas along with heat inside the double entry
cyclone. The first outlet is utilized for releasing the dehydrated
silica particles. The second outlet is utilized for releasing the
water molecules and other gases after performing dehydroxylation of
the fumed silica particles
[0005] A primary object of the present disclosure is to provide a
system to perform separation of fumed silica particles from a
gaseous stream.
[0006] Another object of the present disclosure is to provide the
system to perform dehydroxylation of the fumed silica
particles.
[0007] Yet another object of the present disclosure is to provide
the system to perform separation and dehydroxylation of the fumed
silica particles in a double entry cyclone separator.
[0008] Yet another object of the present disclosure is to reduce
overall time while performing separation and dehydroxylation of the
fumed silica particles.
[0009] Yet another object of the present disclosure is to increase
production and minimize wastage after performing separation and
dehydroxylation of the fumed silica particles.
[0010] Yet another object of the present disclosure is to perform
dehydroxylation of the fluidized (free flowing) fumed silica
particles in a chamber.
[0011] Yet another object of the present disclosure is to perform
dehydroxylation of the fluidized (free flowing) fumed silica
particles in one or more chambers.
[0012] Yet another object of the present disclosure is to perform
dehydroxylation of low porosity with the defined geometry fumed
silica particles.
[0013] In an aspect, the present disclosure provides a separator
system for performing separation and dehydroxylation of fumed
silica particles. The separator system includes a first inlet. The
separator system includes a second inlet. In addition, the
separator system includes a main body of a double entry cyclone.
Further, the separator system includes a first outlet. Furthermore,
the separator system includes a second outlet. The first inlet is
utilized for collecting a primary feed of fumed silica particles
from a gaseous stream into a double entry cyclone. The primary feed
of fumed silica particles is collected in a fluidized (free
flowing) state. The second inlet is utilized for collecting a
secondary feed of chlorine gas into the double entry cyclone. The
secondary feed of chlorine gas is collected for performing
dehydroxylation of the fluidized (free flowing) fumed silica
particles in the cyclone. The main body of the double entry cyclone
is utilized in treating the primary feed of the silica particles
and the secondary feed of chlorine gas along with heat inside the
double entry cyclone. The heat is provided for chemical reaction by
high temperature environment inside the cyclone. The first outlet
is utilized for releasing the dehydrated silica particles. The
second outlet is utilized for releasing the water molecules and
other gases after performing dehydroxylation of the fumed silica
particles.
[0014] In an embodiment of the present disclosure, the vortex
formation imparts centrifugal force on the fluidized (free flowing)
fumed silica particles. The separation and dehydroxylation of the
fumed silica particles happens for releasing dehydrated fumed
silica particles and water molecules.
[0015] In an embodiment of the present disclosure, the fumed silica
particles undergoes dehydroxylation for removing physiosorbed water
molecules and chemisorbed water molecules. The chemisorbed water
molecules are removed after removal of the physiosorbed water
molecules. The physiosorbed water molecules are removed at
temperature of about 200.degree. Celsius. The chemisorbed water
molecules remaining after temperature of 200.degree. Celsius is in
range of about 30 parts per million to 50 parts per million.
[0016] In an embodiment of the present disclosure, the separator
system (100) performs dehydroxylation of isolated SiOH groups,
geminal SiOH groups and vicinal SiOH groups. The dehydroxylation of
isolated SiOH groups, geminal SiOH groups and vicinal SiOH groups
is defined by rate law
dC dt = - k [ c ] n ##EQU00001##
at temperature in range of about 320.degree. Celsius to
1200.degree. Celsius.
[0017] In an embodiment of the present disclosure, the fumed silica
particles undergoes separation and dehydroxylation in a time
period. The time period for separation and dehydroxylation of the
fumed silica particles depends upon one or more factors.
[0018] In an aspect, the present disclosure provides a method. The
method performs separation of fumed silica particles. The method
includes a first step to collect a primary feed of fumed silica
particles from a gaseous stream into a double entry cyclone from a
first inlet. The method includes another step to collect a
secondary feed of chlorine gas into the double entry cyclone from a
second inlet. The method includes another step to treat the primary
feed of the fumed silica particles and the secondary feed of
chlorine gas along with heat inside a main body of the double entry
cyclone. The method includes another step to release the dehydrated
fumed silica particles from a first outlet. The method includes
another step to release the water molecules and other gases after
performing separation of the fumed silica particles from a second
outlet. The primary feed of fumed silica particles is collected in
a fluidized (free flowing) state. The secondary feed of chlorine
gas is collected to perform dehydroxylation of the fluidized (free
flowing) fumed silica particles.
[0019] In an embodiment of the present disclosure, the method
includes another step to perform dehydroxylation of the fluidized
(free flowing) fumed silica particles in a chamber. The
dehydroxylation is performed after performing separation of the
fumed silica particles in the double entry cyclone. The chamber is
surrounded by one or more induction furnaces.
[0020] In an embodiment of the present disclosure, the method
includes another step to perform dehydroxylation of the fluidized
(free flowing) fumed silica particles in one or more chambers. The
dehydroxylation is performed after performing separation of the
fumed silica particles in the double entry cyclone. The one or more
chambers are surrounded by one or more induction furnaces.
[0021] In an embodiment of the present disclosure, the method
includes another step to perform compaction of the fluidized (free
flowing) fumed silica particles using a punch and a die apparatus.
The compaction is performed after performing separation of the
fumed silica particles in the double entry cyclone. The compaction
is performed for performing dehydroxylation of compacted fumed
silica particles.
BRIEF DESCRIPTION OF FIGURES
[0022] Having thus described the disclosure in general terms,
reference will now be made to the accompanying figures,
wherein:
[0023] FIG. 1 illustrates a three dimensional view of a system to
perform separation and dehydroxylation of fumed silica particles,
in accordance with various embodiments of the present
disclosure;
[0024] FIG. 2 illustrates a two dimensional view of the separator
system to perform separation and dehydroxylation of fumed silica
particles, in accordance with various embodiments of the present
disclosure;
[0025] FIG. 3 illustrates a general overview of a chamber to
perform dehydroxylation of fluidized (free flowing) fumed silica
particles, in accordance with various embodiments of the present
disclosure;
[0026] FIG. 4 illustrates a general overview of one or more
chambers to perform dehydroxylation of fluidized (free flowing)
fumed silica particles, in accordance with various embodiments of
the present disclosure; and
[0027] FIG. 5 illustrates a general overview of a mold assembly to
perform compaction of fluidized (free flowing) fumed silica
particles, in accordance with various embodiments of the present
disclosure.
[0028] It should be noted that the accompanying figures are
intended to present illustrations of exemplary embodiments of the
present disclosure. These figures are not intended to limit the
scope of the present disclosure. It should also be noted that
accompanying figures are not necessarily drawn to scale.
DETAILED DESCRIPTION
[0029] In the following description, for purposes of explanation,
numerous specific details are set forth in order to provide a
thorough understanding of the present technology. It will be
apparent, however, to one skilled in the art that the present
technology can be practiced without these specific details. In
other instances, structures and devices are shown in block diagram
form only in order to avoid obscuring the present technology.
[0030] Reference in this specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the present technology. The
appearance of the phrase "in one embodiment" in various places in
the specification are not necessarily all referring to the same
embodiment, nor are separate or alternative embodiments mutually
exclusive of other embodiments. Moreover, various features are
described which may be exhibited by some embodiments and not by
others. Similarly, various requirements are described which may be
requirements for some embodiments but not other embodiments.
[0031] Moreover, although the following description contains many
specifics for the purposes of illustration, anyone skilled in the
art will appreciate that many variations and/or alterations to said
details are within the scope of the present technology. Similarly,
although many of the features of the present technology are
described in terms of each other, or in conjunction with each
other, one skilled in the art will appreciate that many of these
features can be provided independently of other features.
Accordingly, this description of the present technology is set
forth without any loss of generality to, and without imposing
limitations upon, the present technology.
[0032] FIG. 1 illustrates a general overview of a separator system
100 to perform separation and dehydroxylation of fumed silica
particles, in accordance with various embodiments of the present
disclosure. FIG. 2 illustrates a two dimensional view of the
separator system 100 to perform separation and dehydroxylation of
fumed silica particles, in accordance with various embodiments of
the present disclosure. The separator system 100 performs
separation and separation of the fumed silica particles. The
separator system 100 includes a first inlet 102, and a second inlet
104. In addition, the separator system 100 includes a main body 106
of a double entry cyclone, a first outlet 108 and a second outlet
110.
[0033] In general, silica particles are white flaky substance
consisting largely of silica, used in manufacturing of optical
fibre preforms. In general, dehydroxylation is loss or removal of
water from something. In addition, dehydroxylation involves heating
process through which hydroxyl group (OH) is released by forming
water molecule.
[0034] The separator system 100 includes the first inlet 102. The
first inlet 102 is utilized to collect a primary feed of fumed
silica particles from a gaseous stream into the double entry
cyclone. In an embodiment of the present disclosure, the primary
feed comes from particle generation system. In addition, the
primary feed contains the fumed silica particles and other gases.
The first inlet 102 collects the primary feed of silica particles
in a fluidized (free flowing) state. In an embodiment of the
present disclosure, the first inlet 102 passes the primary feed of
the fumed silica particles inside the main body 106 of the double
entry cyclone.
[0035] The separator system 100 includes the second inlet 104. The
second inlet 104 is utilized to collect a secondary feed of
chlorine gas into the double entry cyclone. The second inlet 104
collects the secondary feed of chlorine gas to perform
dehydroxylation of fluidized (free flowing) fumed silica particles.
In an embodiment of the present disclosure, the second inlet 104
passes the secondary feed of the fumed silica particles inside the
main body 106 of the double entry cyclone.
[0036] In an embodiment of the present disclosure, the first inlet
102 collects the secondary feed of chlorine gas into the double
entry cyclone. In an embodiment of the present disclosure, the
second inlet 104 collects the primary feed of the fumed silica
particles from the gaseous stream into the double entry cyclone. In
other words, the first inlet 102 and the second inlet 104 may
operate interchangeably.
[0037] In an embodiment of the present disclosure, the primary
inlet creates a suction pressure to collect the primary feed of
fumed silica particles into the double entry cyclone. In an
embodiment of the present disclosure, the secondary inlet creates a
suction pressure to collect the secondary feed of chlorine gas into
the double entry cyclone. In an embodiment of the present
disclosure, the first inlet 102 includes a plurality of nozzles to
shower the primary feed of fumed silica particles into the double
entry cyclone. In an embodiment of the present disclosure, the
second inlet 104 includes the plurality of nozzles to shower the
secondary feed of chlorine gas into the double entry cyclone.
[0038] The separator system 100 includes the main body 106 of the
double entry cyclone. The main body 106 of the double entry cyclone
is utilized to treat the primary feed of the silica particles and
the secondary feed of chlorine gas along with heat inside the
double entry cyclone. In addition, the double entry cyclone imparts
centrifugal force on the fluidized (free flowing) fumed silica
particles to perform dehydroxylation and separation of the fumed
silica particles. In an embodiment of the present disclosure, the
double entry cyclone has higher temperature due to resistance
heating. In general, resistance heating is defined as heat produced
by passing an electric current through a material that preferably
has high resistance. In another embodiment of the present
disclosure, the double entry cyclone has higher temperature due to
induction. In addition, the double entry cyclone is insulated to
prevent leakage of heat from the double entry cyclone.
[0039] In an embodiment of the present disclosure, the vortex
formation is result of design of the double entry cyclone. The
primary inlet and the secondary inlet collects the primary feed and
the secondary feed tangentially such that they result in the vortex
formation inside the double entry cyclone. In an embodiment of the
present disclosure, primary inlet feed tangentially such that they
result in the vortex formation inside the double entry cyclone and
secondary inlet feed perpendicular to the primary flow. In an
embodiment of the present disclosure, secondary inlet feed
tangentially such that they result in the vortex formation inside
the double entry cyclone and primary inlet feed perpendicular to
the primary flow. In an embodiment of the present disclosure,
particulate formed after treatment of the primary feed of the fumed
silica particles and the secondary feed of chlorine gas is
collected in a hopper.
[0040] The separator system 100 includes the first outlet 108. The
first outlet 108 is utilized to release SiO.sub.2 particles. The
first outlet 108 is utilized to release dehydrated fumed silica
particles. Further, the separator system 100 includes the second
outlet 110. The second outlet 110 is utilized to release water
molecules and other gases after performing separation and
dehydroxylation of the fumed silica particles. The other gases
include HCl, Nitrogen, air and the like.
[0041] The fumed silica particles undergoes dehydroxylation to
remove physiosorbed water molecules and chemisorbed water
molecules. In general, water associated with silica is in one of
two forms. The two forms includes pysiosorbed water molecules and
chemisorbed water molecules. Further, the chemisorbed water
molecules includes but may not be limited to vicinal silanols,
geminal silanols, and isolated silanols. The physiosorbed water
molecules are removed at temperature of about 200.degree. Celsius.
The chemisorbed water molecules are removed at temperature greater
than 200.degree. Celsius. In an embodiment of the present
disclosure, the chemisorbed water molecules remaining after
temperature of 200.degree. Celsius is in a range of about 30 parts
per million to 50 parts per million. In another embodiment of the
present disclosure, the range of the chemisorbed water molecules
remaining after temperature of 200.degree. Celsius may vary. In an
embodiment of the present disclosure, the chemisorbed water
molecules remaining after temperature of 200.degree. Celsius is
given by .alpha..sub.OH in a range of 4.6 per nm.sup.2 to 4.9 per
nm.sup.2.
[0042] The physiosorbed water molecules are removed by treating the
fumed silica particles up to temperature of about 200.degree.
Celsius. The chemisorbed water molecules are removed by treating
the fumed silica particles above temperature of 200.degree.
Celsius. In addition, there is a possibility of rehydration of the
water molecules up to temperature in a range of about 400.degree.
Celsius to 500.degree. Celsius.
[0043] The dehydroxylation of the fumed silica particles takes
place in presence of the chlorine gas. The dehydroxylation of
isolated SiOH groups, geminal SiOH groups and vicinal SiOH groups
is defined by rate law
dC dt = - k [ c ] n ##EQU00002##
at temperature in range of about 320.degree. Celsius to
1200.degree. Celsius. In an embodiment of the present disclosure,
value of n is around 0.91 and the value of Ea is around 44.2
kilojoule per mol at temperature in range of 320.degree. Celsius to
431.degree. Celsius. In another embodiment of the present
disclosure, value of n is around 2.00 and the value of Ea is around
88.5 kilojoule per mol at temperature in range of 432.degree.
Celsius to 490.degree. Celsius. In yet another embodiment of the
present disclosure, value of n is around 2.00 and the value of Ea
is around 101.9 kilojoule per mol at temperature in range of
491.degree. Celsius to 637.degree. Celsius. In yet another
embodiment of the present disclosure, value of n is around 2.00 and
the value of Ea is around 116.9 kilojoule per mol at temperature in
range of 638.degree. Celsius to 758.degree. Celsius. In yet another
embodiment of the present disclosure, value of n is around 2.00 and
the value of Ea is around 207.6 kilojoule per mol at temperature in
range of 759.degree. Celsius to 1122.degree. Celsius
[0044] The fumed silica particles undergoes separation and
dehydroxylation in a time period. The time period for separation
and dehydroxylation of the fumed silica particles depends upon one
or more factors. The one or more factors include porosity of the
fumed silica particles, geometry of the fumed silica particles,
quantity of the fumed silica particles, temperature inside the
double entry cyclone, the size of the cyclone, and the like. In an
embodiment of the present disclosure, the time period required for
dehydroxylation of the fumed silica particles depends on diffusion
of chlorine in the silica silica.
[0045] In an example, the dehydroxylation of the water molecules
from concentration of 30 parts per million at a temperature of
200.degree. Celsius to concentration of 0.1 parts per million for a
given geometry and density takes place in time period of about 2
hours when treated at temperature of about 1100.degree. Celsius. In
another example, the time period required for dehydration of the
fluidized (free flowing) silica particles of given mass is in a
range of about 10 minutes to 15 minutes. In another example, the
time period required for dehydration of the fluidized (free
flowing) silica particles depends on particles flowing length
inside the cyclone. In addition, the time taken for thermal
diffusion depends on density and geometry of optical fiber
preform.
[0046] In an embodiment of the present disclosure, the dehydrated
fumed silica particles from the first outlet 108 of the double
entry cyclone are stored in a storage tank. The dehydrated fumed
silica particles are stored into the storage tank at a flow rate of
about 500 grams per minute. In an embodiment of the present
disclosure, the dehydrated fumed silica particles are stored into
the storage tank at any suitable flow rate.
[0047] FIG. 3 illustrates a general overview 300 of a chamber 302
to perform dehydroxylation of fluidized (free flowing) fumed silica
particles, in accordance with various embodiments of the present
disclosure. The chamber 302 is placed below the storage tank 304
placed below the first outlet 108 of the double entry cyclone. In
an embodiment of the present disclosure, the chamber 302 is
utilized to perform dehyroxylation of the fluidized (free flowing)
fumed silica particles. The dehydroxylation is performed after
performing separation of the fumed silica particles in the double
entry cyclone. The chamber 302 is surrounded by one or more
induction furnaces. The one or more induction furnaces provide heat
to the chamber 302.
[0048] In an embodiment of the present disclosure, the chamber 302
has height of 7 meter. In another embodiment of the present
disclosure, height of the chamber 302 may vary. In an embodiment of
the present disclosure, the chamber 302 has radius of 10.2
centimeter. In another embodiment of the present disclosure, radius
of the chamber 302 may vary. In an embodiment of the present
disclosure, the chamber 302 is made of quartz. In another
embodiment of the present disclosure, the chamber 302 is made of
any other suitable material of the like. In an example, the chamber
302 is capable to treat the fumed silica particles up to weight of
25 kilogram continuously for one hour. In an another example the
chamber 302 may be suitably modified to treat the fumed silica
particles up to any defined weight for a predetermined time.
[0049] FIG. 4 illustrates a general overview 400 of one or more
chambers 302 to perform dehydroxylation of free flowing fumed
silica particles, in accordance with various embodiments of the
present disclosure. The one or more chambers 302 are placed below
the storage tank 304 placed below the first outlet 108 of the
double entry cyclone. In another embodiment of the present
disclosure, the dehydroxylation is performed after performing
separation of the fumed silica particles in the double entry
cyclone. The one or more chambers 302 are surrounded by one or more
induction furnaces. In addition, each chamber of the one or more
chambers 302 is surrounded by the one or more induction furnaces.
The one or more induction furnaces provide heat to the one or more
chambers 302.
[0050] In an embodiment of the present disclosure, each chamber of
the one or more chambers 302 has height of 2 meter. In another
embodiment of the present disclosure, height of each chamber of the
one or more chambers 302 may vary. In an embodiment of the present
disclosure, each chamber of the one or more chambers 302 has radius
of 8.5 centimeter. In another embodiment of the present disclosure,
radius of each chamber of the one or more chambers 302 may vary. In
an embodiment of the present disclosure, each chamber of the one or
more chambers 302 is made of quartz. In another embodiment of the
present disclosure, each chamber of the one or more chambers 302 is
made of any other suitable material of the like. In an example, the
one or more chambers 302 are capable to treat the fumed silica
particles up to weight of 5 kilogram continuously for one hour. In
an another example the one or more chambers 302 may be suitably
modified to treat the fumed silica particles up to any defined
weight for a predetermined time.
[0051] FIG. 5 illustrates a general overview of a mold assembly 500
to perform compaction of fluidized fumed silica particles 502, in
accordance with various embodiments of the present disclosure. The
fluidized fumed silica particles 502 are separated silica particles
released from the first outlet 108 of FIG. 1. The mold assembly 500
includes a punching machine 504, a pressing die 506 and a
cylindrical shaped rod 508. The punching machine and the pressing
die represent a punch and a die apparatus. The punch and the die
apparatus is used to perform compaction of the fluidized fumed
silica particles 502. The fluidized fumed silica particles 502 are
low porosity with the defined geometry fumed silica particles. The
dehydroxylation of the low porosity with the defined geometry fumed
silica particles is achieved after compaction. The compaction is
performed after performing separation of the fumed silica particles
in the double entry cyclone (as shown in FIG. 1 and FIG. 2). In
addition, the compaction is performed for performing
dehydroxylation of compacted fumed silica particles.
[0052] The fluidized fumed silica particles 502 are compacted using
the mold assembly 500 to manufacture compact silica particles.
object. In addition, the compacted object is sintered to
manufacture a clad preform. The mold assembly 500 performs pressing
of the fluidized fumed silica particles 502. The pressing of the
fluidized fumed silica particles 502 is a compaction of the
fluidized fumed silica particles 502 to manufacture the compact
object as preform.
[0053] The mold assembly 500 includes the pressing die 506. In
general, die is a specialized tool used in manufacturing industries
to cut or shape material, mostly using a press. In addition, dies
are customized according to shape and size of target products. In
an embodiment of the present disclosure, cross-section of the
pressing die 506 is cylindrical. The pressing die 506 is used for
manufacturing of the compact object of cylindrical shape. In an
embodiment of the present disclosure, the pressing die 506 has a
cylindrical shape cavity at a central position. In an embodiment of
the present disclosure, the cylindrical shape cavity is on upper
surface of the pressing die 506 for positioning of the cylindrical
shaped rod 508.
[0054] In an embodiment of the present disclosure, the cylindrical
shaped rod 508 is a mold rod used for manufacturing of hollow
compact object. In an embodiment of the present disclosure, the
length of the cylindrical shaped rod 508 is defined according to
required length of the clad preform.
[0055] In an embodiment of the present disclosure, the pressing die
506 has cavity around the cylindrical shaped rod 508. The shape and
size of the cavity around the cylindrical shaped rod 508 is defined
according to the shape and size of the required clad preform. In an
embodiment of the present disclosure, the pressing die 506 has a
first wall and a second wall. The first wall is an inner wall of
the pressing die 506. The fluidized fumed silica particles 502 are
loaded in between the cylindrical shaped rod 508 and inner wall of
the pressing die 506.
[0056] The fluidized fumed silica particles 502 are loaded inside
the cavity of the pressing die 506 from the storage tank 304. In an
embodiment of the present disclosure, the cavity of the pressing
die 506 is cylindrical in shape. The fluidized fumed silica
particles 502 are loaded inside the cavity of the pressing die 506
based on the required size of the clad preform.
[0057] The fluidized fumed silica particles 502 present inside the
cavity of the pressing die 506 are pressed using the punching
machine 504. The punching machine 504 is a machine tool for
punching or pressing of the fluidized fumed silica particles 502 to
convert the fluidized fumed silica particles 502 into the compact
object. In an embodiment of the present disclosure, the punching
machine 504 is one of automatic machine or manual machine. In
another embodiment of the present disclosure, the punching machine
504 works on hydraulic press. The fluidized fumed silica particles
502 are axially compressed or pressed to form the compact object
around the cylindrical shaped rod 508. The punching machine 504 is
used to apply pressure on the fluidized fumed silica particles 502
to form the compact object. The pressure is applied towards the
pressing die 506 to press the fluidized fumed silica particles 502.
In addition, the pressure is applied to press the fluidized fumed
silica particles 502 to form the compact object of target
density.
[0058] In an embodiment of the present disclosure, the fluidized
fumed silica particles 502 are pressed using cold press technique.
In general, cold press technique refers to the pressing of the
dehydrated silica particles in mold assembly below sintering
temperature or at room temperature. The cold pressing of the
fluidized fumed silica particles 502 is performed to provide proper
shape and density to the required clad preform.
[0059] In another embodiment of the present disclosure, the
fluidized fumed silica particles 502 are pressed using hot press
technique. In general, hot press technique refers to pressing of
dehydrated silica particles using heated pressing die. In an
embodiment of the present disclosure, the mold assembly 500 is
enclosed inside one or more furnaces to increase temperature for
pressing of the fluidized fumed silica particles 502. The one or
more furnaces enables heating of the pressing die 506 for
manufacturing of the compact object. In an embodiment of the
present disclosure, the pressing die 506 is heated using radiation
or convection to reach the desired temperature for the compaction
of the fluidized fumed silica particles 502. In another embodiment
of the present disclosure, the pressing die 506 is heated using
induction or resistance techniques. In yet another embodiment of
the present disclosure, the pressing die 506 is heated using any
other suitable technique of the like. In an embodiment of the
present disclosure, uniaxial pressing is done for the compaction of
the fluidized fumed silica particles 502 in the heated pressing die
506. In another embodiment of the present disclosure, isostatic
pressing is done for the compaction of the fluidized fumed silica
particles 502 in the heated pressing die 506. The uniaxial pressing
or isostatic pressing is done for the manufacturing of the compact
object.
[0060] In an embodiment of the present disclosure, the compaction
of the fluidized fumed silica particles 502 result in the decrease
in volume and increase in density of the compact object. In an
embodiment of the present disclosure, an inward pressure is applied
on the fluidized fumed silica particles 502 to form the compact
object. In an embodiment of the present disclosure, the punching
machine 504 uniformly presses the fluidized fumed silica particles
502 from one or more sides of the pressing die 506.
[0061] The mold assembly 500 enables conversion of the fluidized
fumed silica particles 502 into the cylindrical shape compact
object. In addition, the pressing die 506 along with the punching
machine 504 enable the conversion of the fluidized fumed silica
particles 502 into the compact object with defined or target
density.
[0062] In an embodiment of the present disclosure, the cylindrical
shaped rod 508 is inserted into the mold assembly 500 for the
formation of the hollow cylindrical shaped compact object. The
hollow cylindrical shaped compact object is sintered for the
formation of the hollow cylindrical shaped clad preform. In an
embodiment of the present disclosure, the hollow cylindrical shaped
compact object is sintered in a sintering furnace for the formation
of the hollow cylindrical shaped clad preform. In general,
sintering refers to a process of forming a glass preform or clad
preform from the compacted object with facilitation of heat without
melting compacted object to point of liquefaction. In an example,
the hollow cylindrical shaped clad preform has a porosity of about
0.5. In another example, porosity of the hollow cylindrical shaped
clad preform may vary. In general, porosity refers to bulk density
of hollow cylindrical shape.
[0063] In an embodiment of the present disclosure, the double entry
cyclone separator performs both separation and dehydroxylation of
the fumed silica particles. In another embodiment of the present
disclosure, the double entry cyclone separator performs
dehydroxylation of the fumed silica particles. In an embodiment of
the present disclosure, the dehydroxylation of the fumed silica
particles is performed at a high temperature. In yet another
embodiment of the present disclosure, the double entry cyclone
separator performs only separation of the fumed silica particles.
In that case, the dehydroxylation of the fumed silica particles is
performed in the chamber (as shown in FIG. 3), in the one or more
chambers (as shown in FIG. 4), or after compaction of the fluidized
fumed silica particles (as shown in FIG. 5).
[0064] 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 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 intended to cover the
application or implementation without departing from the spirit or
scope of the claims of the present technology.
[0065] While several possible embodiments of the disclosure have
been described above and illustrated in some cases, it should be
interpreted and understood 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.
* * * * *