Note: Descriptions are shown in the official language in which they were submitted.
CHF-0007-CA
Process for Producing Loose Tube for Totally Gel-free Fiber Optic Cable
and Device for Molding the Same
Cross-Reference to Related Applications
The present disclosure claims priority of Chinese Patent Application No.
201811596468.6, filed with the Chinese Patent Office on December 25, 2018,
entitled "Process for Producing Loose tube for Totally Gel-free Fiber Optic
Cable and Device for Molding the Same".
Technical Field
The present disclosure relates to the technical field of processing and
manufacturing of optical fibers and optical fiber cables, and in particular to
a
process for producing a loose tube for a totally gel-free fiber optic cable
and to
a device for molding the same.
Background Art
At present, loose tubes used in optical fiber cables are mainly of the gel-
filled
(grease-filled) type, that is to say, a loose tube is filled with gel to
protect an
optical fiber and ensure that the loose tube for the optical fiber is
impermeable
to water; and when the loose tube is being molded, the filled gel also serves
the
function of supporting and rounding off the loose tube.
In construction using a totally gel-free fiber optic cable which is a grease-
free
optical fiber cable, a process of removing the gel is omitted, so that the
construction efficiency is improved, and also environmental pollution is
avoided,
and hence it is an environmentally-friendly optical fiber cable for outdoor
use.
When the loose tube in the totally gel-free fiber optic cable is molded by
extrusion, the loose tube tends to have a flat shape, and the optical fiber is
prone to adhere to the loose tube, which causes an unsatisfactory attenuation
index of the optical fiber.
Summary
The objects of the present disclosure include, for example, providing a
process for producing a loose tube for a totally gel-free fiber optic cable to
alleviate the technical problem in the related art that the loose tube tends
to
have a flat shape when being molded by extrusion, and the optical fiber is
prone
to adhere to the loose tube, which causes an unsatisfactory attenuation index
of the optical fiber.
The objects of the present disclosure further includes, for example, providing
a device for molding a loose tube for a totally gel-free fiber optic cable to
alleviate the technical problem in the related art that the loose tube tends
to
have a flat shape when being molded by extrusion, and the optical fiber is
prone
CA 3067014 2020-01-08
CHF-0007-CA
to adhere to the loose tube, which causes an unsatisfactory attenuation index
of the optical fiber.
Embodiments of the present disclosure are implemented as follows:
An embodiment of the present disclosure provides a process for producing a
loose tube for a totally gel-free fiber optic cable, comprising steps of:
extruding a loose tube material into a loose tube of a tubular shape by a
loose
tube molding device;
filling a compressed gas into the loose tube;
cooling the loose tube;
to threading an optical fiber or an optical fiber ribbon into the loose
tube.
An embodiment of the present disclosure provides a process for producing a
loose tube for a totally gel-free fiber optic cable, comprising steps of:
filling a compressed gas into a tube cavity of a loose tube during extrusion
and molding.
Optionally, the molded loose tube is cooled.
Optionally, the process for producing a loose tube for a totally gel-free
fiber
optic cable further comprises:
threading an optical fiber or an optical fiber ribbon into the tube cavity of
the
loose tube.
Optionally, the process step of filling the compressed gas into the tube
cavity
of the loose tube comprises:
purifying and dehumidifying the compressed gas, and filling the compressed
gas into the loose tube through a gas storage tank and a flow controller.
Optionally, the process step of cooling the loose tube comprises:
winding the loose tube around a primary pulling roller after the loose tube
passes through a first cooling groove;
unwinding the loose tube wound around the primary pulling roller and passing
the loose tube through a second cooling groove and an auxiliary pulling
roller;
introducing the loose tube into a take-up device and taking up the loose tube
on a take-up reel of the take-up device.
An embodiment of the present disclosure further provides a device for
molding a loose tube for a totally gel-free fiber optic cable, comprising: a
head,
a mold core, and a mold sleeve, wherein the head is provided with a
ventilation
hole, the mold core is mounted to the head, the mold core is provided with a
mold core through hole, and the mold core through hole communicates with the
2
CA 3067014 2020-01-08
CHF-0007-CA
ventilation hole; the mold sleeve is sleeved around an outer circumference of
the mold core and a molding space is formed between the mold core and the
mold sleeve, and the molding space communicates with the outside.
Optionally, the mold core comprises a first tapered section and a first
cylindrical section, wherein the first cylindrical section is connected with
an end
of the first tapered section having a smaller inner diameter; the mold sleeve
comprises a second tapered section and a second cylindrical section, wherein
the second cylindrical section is connected with an end of the second tapered
section having a smaller inner diameter; and
the second tapered section is sleeved around an outer circumference of the
first tapered section and a tapered space is defined therebetween, the second
cylindrical section is sleeved around an outer circumference of the first
cylindrical section and a cylindrical space is defined therebetween, and the
tapered space and the cylindrical space communicate with each other and form
the molding space.
Optionally, the mold core further comprises a plugging section, wherein the
plugging section is connected with an end of the first tapered section that is
remote from the first cylindrical section, and the mold core through hole
sequentially penetrates the plugging section, the first tapered section, and
the
first cylindrical section; and the plugging section is inserted into the
ventilation
hole.
Optionally, the molding device further comprises a gas filling base mounted
to the head, wherein the gas filling base is provided with a gas filling inlet
and
a gas delivery hole, and the gas delivery hole communicates with the gas
filling
inlet and the ventilation hole, respectively.
Optionally, the gas filling inlet is provided in a side wall of the gas
filling base,
and the gas delivery hole penetrates the gas filling base in a length
direction of
the gas filling base.
Optionally, an annular sealing protrusion is provided on an outer
circumferential surface of the gas filling base, the gas filling base has an
insertion portion, and the insertion portion is inserted into the ventilation
hole
and the annular sealing projection abuts against an outer wall of the head.
Optionally, the device for molding a loose tube for a totally gel-free fiber
optic
cable further comprises a pressure ring, wherein the pressure ring is sleeved
outside the gas filling base, the pressure ring is connected with the head,
and
the annular sealing protrusion is clamped between the pressure ring and the
head.
Optionally, the device for molding a loose tube for a totally gel-free fiber
optic
cable further comprises a sealing gasket, wherein the sealing gasket is
located
3
CA 3067014 2020-01-08
CHF-0007-CA
between the gas filling base and the head and is configured to seal a
connection
position between the gas filling base and the head.
Optionally, a pressure relief valve is mounted to the gas filling base, and
the
pressure relief valve communicates with the gas delivery hole.
Optionally, the molding device further comprises an optical fiber guiding
mechanism, wherein the optical fiber guiding mechanism is connected with the
head, and an interior of the optical fiber guiding mechanism communicates with
the mold core through hole.
Optionally, the optical fiber guiding mechanism comprises a syringe holder
and a guiding component, wherein the syringe holder is mounted to the head,
and the syringe holder is provided with a guiding through hole communicating
with the mold core through hole; and the guiding component is mounted in the
guiding through hole.
Optionally, the syringe holder is located in the gas delivery hole, a gap is
provided between an outer wall of the syringe holder and an inner wall of the
gas delivery hole, and one end of the syringe holder is inserted into the mold
core through hole, and a gap is provided between the syringe holder and an
inner wall of the mold core through hole so that the gas delivery hole, the
ventilation hole, and the mold core through hole communicate with one another
sequentially.
Optionally, the syringe holder comprises a connecting portion and a guiding
portion connected with each other, the guiding through hole sequentially
penetrates the connecting portion and the guiding portion, the guiding portion
passes through the gas delivery hole and is inserted into the mold core
through
hole, and the connecting portion is connected with the gas filling base.
Optionally, the guiding component comprises a first optical fiber guiding
syringe and a second optical fiber guiding syringe, wherein the first optical
fiber
guiding syringe is mounted to a first end of the syringe holder, and the
second
optical fiber guiding syringe is mounted to a second end of the syringe
holder;
and
the first optical fiber guiding syringe is provided with a first optical fiber
guiding
hole, the second optical fiber guiding syringe is provided with a second
optical
fiber guiding hole, and both the first optical fiber guiding hole and the
second
optical fiber guiding hole communicate with the guiding through hole.
Compared with the prior art, the embodiments of the present disclosure bring,
for example, the following advantageous effects:
The present disclosure provides a process for producing a loose tube for a
totally gel-free fiber optic cable and a device for molding the same. The
process
for producing a loose tube for a totally gel-free fiber optic cable comprises:
extruding a loose tube material into a loose tube of a tubular shape by using
a
4
CA 3067014 2020-01-08
C HF-0007-CA
loose tube molding device; filling a compressed gas into the loose tube;
cooling
the loose tube; threading an optical fiber or an optical fiber ribbon into the
loose
tube. The interior of the loose tube is supported by the compressed gas, so
that
the outer diameter of the loose tube is not affected by a fluctuation of the
gas
pressure, the loose tube has a rounded and smooth outer diameter, and it can
be ensured that an appropriate excess length of an optical fiber is formed in
the
loose tube, so that the optical fiber has satisfactory transmission
performance,
and the optical fiber has a stable excess length and a good attenuation index.
Brief Description of Drawings
In order to more clearly illustrate technical solutions of specific
embodiments
of the present disclosure or in the related art, drawings required for use in
the
description of the specific embodiments or the related art will be described
briefly below. It is apparent that the drawings below are merely illustrative
of
some embodiments of the present disclosure. It will be understood by those of
ordinary skill in the art that other drawings can also be obtained based on
these
drawings without any inventive effort.
FIG. 1 is a sectional view of a device for molding a loose tube for a totally
gel-
free fiber optic cable according to the present disclosure; and
FIG. 2 is a partially enlarged schematic view of FIG. 1.
Reference Numerals: 100-head; 001-ventilation hole; 200-mold core; 201-
mold core through hole; 210-plugging section; 220-first tapered section; 230-
first cylindrical section; 300-mold sleeve; 310-second tapered section; 320-
second cylindrical section; 400-gas filling base; 410-gas filling inlet; 411-
gas
delivery hole; 420-pressure relief valve; 430-positioning pin; 440-sealing
gasket;
450-annular sealing protrusion; 460-insertion portion; 470-deflation hole; 500-
optical fiber guiding mechanism; 510-syringe holder; 511-bolt; 512-guiding
through hole; 513-connecting portion; 514-guiding portion; 502-guiding
component; 520-first optical fiber guiding syringe; 530-second optical fiber
guiding syringe; 600-molding space; 610-tapered space; 620-cylindrical space;
630-outlet end; 700-pressure ring.
Detailed Description of Embodiments
In order to make the objects, technical solutions, and advantages of the
embodiments of the present disclosure more clear, the technical solutions of
the present disclosure will be described below clearly and completely with
reference to the accompanying drawings. It is apparent that the embodiments
to be described are some, but not all of the embodiments of the present
disclosure. Generally, the components of the embodiments of the present
disclosure, as described and illustrated in the figures herein, may be
arranged
and designed in a wide variety of different configurations.
5
CA 3067014 2020-01-08
CHF-0007-CA
Thus, the following detailed description of the embodiments of the present
disclosure, as represented in the figures, is not intended to limit the scope
of
the present disclosure as claimed, but is merely representative of selected
embodiments of the present disclosure. All the other embodiments obtained by
those of ordinary skill in the art in light of the embodiments of the present
disclosure without inventive efforts shall fall within the scope of the
present
disclosure as claimed.
It should be noted that similar reference numerals and letters refer to
similar
items in the following figures, and thus once an item is defined in one
figure, it
may not need be further defined or explained in the subsequent figures.
Throughout the description of the present disclosure, it should be noted that
orientation or positional relations indicated by the terms such as "center",
"up",
"down", "left", "right", "vertical", "horizontal", "inside", and "outside", if
present,
are based on the orientation or positional relations shown in the figures, or
the
orientation or positional relations in which the inventive product is
conventionally placed in use, and these terms are intended only to facilitate
the
description of the present disclosure and simplify the description, but not
intended to indicate or imply that the referred devices or elements must be in
a
particular orientation or constructed or operated in the particular
orientation,
and therefore should not be construed as limiting the present disclosure.
In addition, the terms such as "first", "second", and "third", if present, are
used
for distinguishing the description only, and should not be understood as an
indication or implication of relative importance.
In addition, the terms "horizontal", "vertical", "overhanging", or the like,
if
present, does not mean that a component is required to be absolutely
horizontal
or overhanging, but means that the component may be slightly inclined. For
example, the term "horizontal" simply means that the component's direction is
more horizontal than that indicated by the term "vertical", and it does not
mean
that the structure must be completely horizontal, but it means that the
structure
may be slightly inclined.
In the description of the present disclosure, it should also be noted that the
terms "disposed", "mounted", "coupled", and "connected", if present, should be
understood broadly unless otherwise expressly specified or defined. For
example, a connection may be fixed connection or detachable connection or
integral connection, may be mechanical connection or electrical connection, or
may be direct coupling or indirect coupling via an intermediate medium or
internal communication between two elements. The specific meanings of the
above-mentioned terms in the present disclosure can be understood by those
of ordinary skill in the art according to specific situations.
It should be noted that the features in the embodiments of the present
disclosure may be combined with each other without conflict.
6
CA 3067014 2020-01-08
CHF-0007-CA
A process for producing a loose tube for a totally gel-free fiber optic cable
according to the present disclosure comprises the following steps of:
extruding a loose tube material into a loose tube of a tubular shape by using
a loose tube molding device;
filling a compressed gas into the loose tube during the molding of the loose
tube;
cooling the loose tube;
threading an optical fiber or an optical fiber ribbon into a tube cavity of
the
cooled loose tube.
Optionally, the process step of filling the compressed gas into the loose tube
comprises:
purifying and dehumidifying the compressed gas, and then filling the
dehumidified compressed gas into the loose tube through a gas storage tank
and a flow controller. In other words, the compressed gas is purified and
dehumidified and then stored in a gas storage tank, and then the compressed
gas in the gas storage tank is filled into the tube cavity of the loose tube
through
a pipeline, a flow controller is disposed on a delivery pipeline between the
gas
storage tank and the loose tube, and the flow controller is configured to
control
a flow rate of the compressed gas in the pipeline. Optionally, the flow
controller
includes a flow valve mounted on the delivery pipeline between the gas storage
tank and the loose tube.
Optionally, the process step of cooling the loose tube comprises:
winding the loose tube around a primary pulling roller after the loose tube
passes through a first cooling groove (or cooling tank);
pass the loose tube through a second cooling groove and an auxiliary pulling
roller; in other words, the loose tube cooled by the first cooling groove is
wound
around the primary pulling roller, and then the loose tube is unwound from the
primary pulling roller and then introduced into the second cooling groove and
is
subjected to a secondary cooling by the second cooling groove, and the loose
tube after the secondary cooling is wound around the auxiliary pulling roller;
and
introducing the loose tube into a take-up device and taking up the loose tube
on a take-up reel. In this step, the loose tube after being subjected to the
secondary cooling and wound around the auxiliary pulling roller is introduced
into a take-up device (or wire taking-up device) and taken up on a take-up
reel
(or wire taking-up reel) of the take-up device.
The present disclosure further provides a device for molding a loose tube for
a totally gel-free fiber optic cable to alleviate the technical problem in the
related
art that the loose tube tends to have a flat shape when being molded by
7
CA 3067014 2020-01-08
CHF-0007-CA
extrusion, and the optical fiber is prone to adhere to the loose tube, which
causes an unsatisfactory attenuation index of the optical fiber.
As shown in FIG. 1, the device for molding a loose tube for a totally gel-free
fiber optic cable according to the present disclosure comprises: a head 100, a
mold core 200, and a mold sleeve 300, wherein the head 100 is provided with
a ventilation hole 001, the mold core 200 is connected with the head 100, one
end of the mold core 200 is inserted into the ventilation hole 001 of the head
100, and the other end of the mold core 200 protrudes from the head 100; the
mold core 200 is provided with a mold core through hole 201, and the mold core
to through hole
201 communicates with the ventilation hole 001; the mold sleeve
300 is sleeved around an outer circumference of a portion of the mold core 200
that protrudes from the head 100, a molding space 600 is formed between an
inner wall of the mold sleeve 300 and an outer wall of the mold core 200, and
the molding space 600 communicates with the outside. Optionally, the cross
section of the inner wall of the mold sleeve 300 has an annular shape, and
correspondingly, the cross section of the outer wall of the mold core 200 has
an annular shape, and a molding space 600 which has an annular cross section
and is in communication with the outside is formed between the inner wall of
the mold sleeve 300 and the outer wall of the mold core 200.
Optionally, the head 100 is provided with the ventilation hole 001 penetrating
the head 100 in its length direction, and the mold core 200 is mounted to one
end of the ventilation hole 001. The mold core 200 is provided with a mold
core
through hole 201 penetrating the mold core 200 in its length direction, and
the
mold core through hole 201 communicates with the ventilation hole 001 and is
coaxial with the ventilation hole 001. A first end of the mold core 200 is
located
inside the ventilation hole 001, and a second end of the mold core 200 is
located
outside the ventilation hole 001. In other words, the mold core 200 has its
first
end inserted into the ventilation hole 001, and its second end exposed outside
the ventilation hole 001. The mold sleeve 300 is sleeved around the second
end of the mold core 200, the mold sleeve 300 has a molding through hole
penetrating the mold sleeve 300 in its length direction, and an inner wall of
the
molding through hole is provided to be spaced apart from the outer wall of the
mold core 200 to form the molding space 600.
During the production, a loose tube material extruded from a plastic extruder
is introduced into the molding space 600 from a side of the molding space 600.
Since the head 100, the mold core 200, and the mold sleeve 300 are all kept
fixed to one another, in other words, the molding space 600 is kept in a
relatively
fixed shape and size. Under the action of pressing forces from the head 100,
the mold core 200, the mold sleeve 300 and the loose tube material delivered
from the outside, the loose tube material is extruded as a loose tube of a
tubular
shape and the loose tube molded by extrusion is extruded out of the molding
space 600 from the right end of as shown in FIG. 1, that is to say, the molded
loose tube is extruded from an outlet end 630 of the molding space 600. The
8
CA 3067014 2020-01-08
CHF-0007-CA
extruded-out loose tube facilitates subsequent process operations. During the
= molding, the tube cavity of the loose tube communicates with the mold
core
through hole 201. After a compressed gas is fed into the ventilation hole 001,
the compressed gas is introduced into the tube cavity of the loose tube
through
the ventilation hole 001 and the mold core through hole 201 to support the
loose
tube so that the loose tube has a rounded and smooth outer diameter, and the
quality of molding of the loose tube is improved.
Optionally, the mold core 200 comprises a plugging section 210, a first
tapered section 220, and a first cylindrical section 230 which are
sequentially
connected. In other words, the mold core 200 comprises a plugging section 210,
a first tapered section 220, and a first cylindrical section 230, wherein the
plugging section 210 is connected with one end of the first tapered section
220,
the other end of the first tapered section 220 is connected with the first
cylindrical section 230, and the mold core through hole 201 sequentially
penetrates the plugging section 210, the first tapered section 220, and the
first
cylindrical section 230. It should be noted that the two ends of the first
tapered
section 220 have unequal inner diameters, the first cylindrical section 230 is
connected with an end of the first tapered section 220 having a smaller inner
diameter, and correspondingly, the plugging section 210 is connected with an
end of the first tapered section 220 having a larger inner diameter.
Optionally,
the inner diameter of the first cylindrical section 230 is equal to the
smallest
inner diameter of the first tapered section 220.
Optionally, the plugging section 210, the first tapered section 220, and the
first cylindrical section 230 are structurally molded integrally, wherein the
first
tapered section 220 is corresponding to a central position of the molding
space
600, and an end of the first cylindrical section 230 that is remote from the
first
tapered section 220 is at the outlet end 630 of the molding space 600, that is
to
say, the mold core through hole penetrating the first cylindrical section 230
communicates with the molding space 600, so that the compressed gas
discharged from the mold core through hole can be introduced into the loose
tube which is already extruded and molded by the molding space 600.
Optionally, the plugging section 210, the first cylindrical section 230, and
the
first tapered section 220 are coaxial. During installation, the plugging
section
210 is inserted into the ventilation hole 001 of the head 100, and the first
tapered
section 220 and the first cylindrical section 230 are exposed from the
ventilation
hole 001.
Optionally, the mold sleeve 300 comprises a second tapered section 310 and
a second cylindrical section 320 connected with each other. It should be noted
that the second cylindrical section 320 is connected with an end of the second
tapered section 310 having a smaller inner diameter. Optionally, the inner
diameter of the second cylindrical section 320 is equal to the smallest inner
diameter of the second tapered section 310. Optionally, the second tapered
9
CA 3067014 2020-01-08
CHF-0007-CA
section 310 and the second cylindrical section 320 are structurally molded
integrally.
During installation, the plugging section 210 is inserted into the ventilation
hole 001 of the head 100, the second tapered section 310 is sleeved around an
outer circumference of the first tapered section 220, and the second
cylindrical
section 320 is sleeved around an outer circumference of the first cylindrical
section 230. Moreover, a spacing is provided between the first tapered section
220 and the second tapered section 310, a spacing is provided between the
second cylindrical section 320 and the first cylindrical section 230, and the
space between the first tapered section 220 and the second tapered section
310 is in communication with the space between the first cylindrical section
230
and the second cylindrical section 320, so as to form the molding space 600.
Referring to FIG. 2, optionally, the second tapered section 310 is disposed
opposite to the first tapered section 220, and a spacing is provided between
an
is inner
peripheral wall of the second tapered section 310 and an outer peripheral
wall of the first tapered section 220 to form a tapered space 610 having an
annular cross section. A tapered angle of the second tapered section 310 is
equal to a tapered angle of the first tapered section 220. The second
cylindrical
section 320 is sleeved around the outer circumference of the first cylindrical
section 230 and disposed coaxially with the first cylindrical section 230, a
spacing is provided between an inner peripheral wall of the second cylindrical
section 320 and an outer peripheral wall of the first cylindrical section 230
to
form a cylindrical space 620, and the tapered space 610 and the cylindrical
space 620 communicate with each other and form the molding space 600.
During the production, the loose tube material is introduced into the molding
space 600. In other words, the loose tube material is first introduced into
the
tapered space 610 of the molding space 600, and then the loose tube material
is moved rightward when viewed from FIG. 1 and is introduced into the
cylindrical space 620 under the action of the external pressing force, and
finally,
the loose tube material is moved from the right end of the molding space 600,
that is to say, the loose tube material is moved toward the outlet end 630 of
the
molding space 600 and is moved out of the outlet end 630. The loose tube
material is wrapped around the mold core 200 during its movement from left to
right, and a loose tube of a tubular shape is formed under the cooperation of
the mold core 200 and the mold sleeve 300 and is moved out of the right end
of the molding space 600. Since the mold core 200 comprises a first tapered
section 220 and the mold sleeve 300 comprises a second tapered section 310,
when the loose tube material between the first tapered section 220 and the
second tapered section 310 is moving toward the outlet end 630 of the molding
space 600 during extrusion, the first tapered section 220 and the second
tapered section 310 serve a guiding function, which facilitates the flow of
the
loose tube material from the tapered space 610 to the cylindrical space 620,
and hence facilitates the molding of the loose tube.
11)
CA 3067014 2020-01-08
CHF-0007-CA
Optionally, the molding device further comprises a gas filling base 400
mounted to the head 100, wherein the gas filling base 400 is provided with a
gas filling inlet 410 and a gas delivery hole 411, and the gas delivery hole
411
communicates with the gas filling inlet 410 and the ventilation hole 001,
respectively.
As shown in FIG. 1, the gas filling base 400 is mounted to the left end of the
head 100 by a positioning pin 430. Obviously, the gas filling base 400 may
also
be welded to the left end of the head 100, or the gas filling base 400 may be
fixed to the left end of the head 100 by bolts. Optionally, a first end of the
gas
filling base 400 is located in the ventilation hole 001, and a second end of
the
gas filling base 400 is located outside the ventilation hole 001; a sealing
gasket
440 is disposed between the gas filling base 400 and the head 100 to improve
the airtightness of the connection position between the gas filling base 400
and
the head 100 to reduce a risk of leakage of the compressed gas. The gas
filling
inlet 410 is provided in a peripheral wall of the second end portion of the
gas
filling base 400 and communicates with the gas delivery hole 411, and the gas
delivery hole 411 is coaxial with the ventilation hole 001.
Optionally, the gas filling base 400 has a cylindrical structure, an annular
sealing protrusion 450 is provided on an outer peripheral wall of the gas
filling
base 400, the gas delivery hole 411 penetrating the gas filling base 400 is
provided in the gas filling base 400 in its length direction, the annular
sealing
protrusion 450 protrudes outward from the outer peripheral wall of the gas
filling
base 400 in a radial direction of the gas delivery hole 411, and the gas
filling
base 400 and the annular sealing protrusion 450 may be integrally molded. The
gas filling inlet 410 is provided in the peripheral wall of the gas filling
base 400,
and the gas filling inlet 410 communicates with the gas delivery hole 411. The
gas filling base 400 has an insertion portion 460 configured to be inserted
into
the ventilation hole 001. After the insertion portion 460 is inserted into the
ventilation hole 001, the gas delivery hole 411 communicates with the
ventilation hole 001. An end of the gas delivery hole 411 that is remote from
the
head 100 is closed, an end surface of the annular sealing protrusion 450 that
is
close to the head 100 is corresponding to an outer side surface of the head
100,
and a sealing gasket 440 is disposed between the annular sealing protrusion
450 and the head 100, and the sealing gasket 440 is pressed and deformed to
realize sealing at the connection position between the annular sealing
protrusion 450 and the head 100. The gas filling inlet 410 and the insertion
portion 460 are respectively located on both sides of the annular sealing
protrusion 450.
Optionally, the molding device further comprises a pressure ring 700, wherein
the pressure ring 700 is sleeved outside the gas filling base 400 and abuts
against a side surface of the annular sealing protrusion 450 that is remote
from
the insertion portion 460, and the pressure ring 700 is fixedly connected with
the head 100. The gas filling base is fixedly connected to the head 100 in an
11
CA 3067014 2020-01-08
CHF-0007-CA
indirect manner by connecting the pressure ring 700 with the head 100, and the
annular sealing protrusion 450 and the sealing gasket are not provided with
hole structures, thus the connection position between the annular sealing
protrusion 450 and the head 100 has a good sealing performance after the
annular sealing protrusion and the head are connected with the head 100. It
should be noted that the pressure ring 700 may be fixedly connected with the
head 100 by positioning pins, or the pressure ring 700 may be welded to the
head 100, or the pressure ring 700 may be fixedly connected with the head 100
by bolts.
The compressed gas is introduced into the gas delivery hole 411 of the gas
filling base 400 through the gas filling inlet 410, and is introduced into the
loose
tube sequentially through the gas delivery hole 411, the ventilation hole 001,
and the mold core through hole 201 to support an inner tube wall of the loose
tube, so that an outer tube wall of the loose tube is kept round and smooth.
Optionally, a pressure relief valve 420 is mounted to the gas filling base
400,
wherein the pressure relief valve 420 is located at a side of the gas filling
base
400, and the pressure relief valve 420 communicates with the gas delivery hole
411.
Optionally, a deflation hole (or gas release hole) 470 is provided in a side
wall
of the gas filling base 400, wherein the deflation hole 470 communicates with
the gas delivery hole 411, and the pressure relief valve 420 is mounted in the
deflation hole 470. During the operation, when the compressed gas is filled
into
the loose tube, and when the gas pressure in the loose tube is greater than a
set value, excess gas in the gas filling base 400 is automatically discharged
through the pressure relief valve 420 to achieve relief of pressure from the
interior of the gas filling base 400, so that the gas pressure in the loose
tube is
kept constant, and the quality of molding of the loose tube is ensured.
Optionally, the molding device further comprises an optical fiber guiding
mechanism 500, and an interior of the optical fiber guiding mechanism 500
communicates with the mold core through hole 201.
An optical fiber bundle or an optical fiber ribbon stack and a water blocking
yarn or a water blocking tape may be introduced into the mold core through
hole 201 by the optical fiber guiding mechanism. Since the mold core through
hole 201 communicates with the interior of the loose tube, the optical fiber
bundle or the optical fiber ribbon stack and the water blocking yarn or the
water
blocking tape may be introduced into the loose tube through the mold core
through hole 201.
Optionally, the optical fiber guiding mechanism 500 comprises a syringe
holder 510 and a guiding component 502, wherein the syringe holder 510 is
mounted to the head 100, the syringe holder 510 is provided with a guiding
through hole 512, and the guiding through hole 512 is connected with the mold
12
CA 3067014 2020-01-08
CHF-0007-CA
core through hole 201; and the guiding component 502 is mounted in the
guiding through hole 512.
Optionally, the syringe holder 510 is mounted to the gas filling base 400. In
other words, the syringe holder 510 is fixed to the head 100 via the gas
filling
base 400. During installation, the syringe holder 510 is inserted into the gas
delivery hole 411 from the left end of the gas delivery hole 411, that is to
say,
the syringe holder 510 is inserted into the gas delivery hole 411 from an end
of
the gas filling base 400 remote from the head 100 to achieve blocking of an
end
of the gas delivery hole 411 that is remote from the head 100. The guiding
through hole 512 penetrates the syringe holder 510 in a length direction of
the
syringe holder 510 and is coaxial with the gas delivery hole 411. The syringe
holder 510 comprises a connecting portion 513 and a guiding portion 514 which
are molded integrally, wherein the guiding portion 514 is located in the gas
delivery hole 411 and has an outer diameter smaller than the diameter of the
gas delivery hole 411, and an annular gap is provided between an outer
peripheral wall of the guiding portion 514 and an inner wall of the gas
filling
base 400 forming the gas delivery hole 411 and the annular gap is configured
to allow the compressed gas to pass therethrough. The connecting portion 513
is mounted to the left end of the gas filling base 400, and the diameter of
the
connecting portion 513 is larger than the diameter of the gas delivery hole
411
to close the left end of the gas delivery hole 411. In other words, a stepped
structure is formed at the connection position between the connecting portion
513 and the guiding portion 514, the guiding portion 514 can be inserted into
the gas delivery hole 411, while the connecting portion 513 is blocked outside
the gas delivery hole 411, and one end surface of the connecting portion 513
is
sealingly fitted with an end surface of the gas filling base 400 that is
remote
from the head 100.
An optical fiber bundle or an optical fiber ribbon stack and a water blocking
yarn or a water blocking tape may be introduced into the mold core through
hole 201 by the guiding component 502. Since the mold core through hole 201
communicates with the interior of the loose tube, the optical fiber bundle or
the
optical fiber ribbon stack and the water blocking yarn or the water blocking
tape
may be introduced into the loose tube through the mold core through hole 201.
The guiding component 502 is mounted to the gas filling base 400 via the
syringe holder 510 to facilitate installation and detachment of the guiding
component 502.
Optionally, the guiding component 502 comprises a first optical fiber guiding
syringe 520 and a second optical fiber guiding syringe 530, wherein the first
optical fiber guiding syringe 520 is mounted to a first end of the syringe
holder
510, and the second optical fiber guiding syringe 530 is mounted to a second
end of the syringe holder 510. During actual installation, the first optical
fiber
guiding syringe 520 is inserted into one end of the guiding through hole 512
provided in the syringe holder 510, and the second optical fiber guiding
syringe
13
CA 3067014 2020-01-08
CHF-0007-CA
530 is inserted into the other end of the guiding through hole 512 provided in
the syringe holder 520.
Optionally, the first optical fiber guiding syringe 520 is provided with a
first
optical fiber guiding hole, the second optical fiber guiding syringe 530 is
provided with a second optical fiber guiding hole, and both the first optical
fiber
guiding hole and the second optical fiber guiding hole communicate with the
guiding through hole 512.
Both the axis of the first optical fiber guiding hole and the axis of the
second
optical fiber guiding hole coincide with the axis of the guiding through hole
512.
The syringe holder 510 is connected with the gas filling base 400 by a bolt
511.
Specifically, the syringe holder 510 is provided with a connecting through
hole
configured to allow the bolt 511 to pass therethrough, the gas filling base
400
is provided with a threaded hole configured to be fitted with the bolt 511,
and
the bolt 511 passes through the connecting through hole and is fitted with the
threaded hole to mount the syringe holder 510 to the gas filling base 400. It
should be noted that the number of the bolts is set as needed. For example, a
plurality of bolts may be provided, and the plurality of bolts are arranged at
even
intervals in the circumferential direction of the gas filling base 400 to
improve
the firmness of the connection between the syringe holder 510 and the gas
filling base 400.
Optionally, the diameter of the connecting through hole is larger than the
diameter of the bolt 511. A radial position of the syringe holder 510 relative
to
the gas filling base 400 is adjusted by adjusting the relative positions of
the axis
of the connecting through hole and the axis of the bolt 511, thereby adjusting
the coaxiality of the first optical fiber guiding hole and the second optical
fiber
guiding hole with the gas delivery hole 411 so as to improve the guiding
precision. After the adjustment is completed, the bolt passes through the
connecting through hole and is screwed into the threaded hole provided in the
gas filling base 400 to achieve the fixed connection of the syringe holder 510
to
the gas filling base 400.
The present disclosure provides a process for producing a loose tube for a
totally gel-free fiber optic cable and a device for molding the same. The
process
for producing a loose tube for a totally gel-free fiber optic cable comprises:
extruding a loose tube material into a loose tube of a tubular shape by using
a
loose tube molding device; filling a compressed gas into a tube cavity of the
loose tube during the molding of the loose tube; cooling the loose tube;
threading an optical fiber or an optical fiber ribbon into the tube cavity of
the
cooled loose tube. In the production process according to the present
disclosure, the compressed gas is continuously fed into the tube cavity of the
loose tube during the extrusion and molding of the loose tube, and the
interior
of the loose tube is supported by the compressed gas, so that the outer
diameter of the loose tube is not affected by a fluctuation of the gas
pressure,
14
CA 3067014 2020-01-08
CHF-0007-CA
the loose tube has a rounded and smooth outer diameter, and it can be ensured
that an appropriate excess length of an optical fiber is formed in the loose
tube,
so that the optical fiber has satisfactory transmission performance, and the
optical fiber has a stable excess length and a good attenuation index.
Finally, it should be noted that the above embodiments are merely intended
to illustrate the technical solutions of the present disclosure, but not
intended to
limit the present disclosure. Although the present disclosure has been
described in detail with reference to the foregoing embodiments, it should be
understood by those of ordinary skill in the art that the technical solutions
disclosed in the foregoing embodiments may still be modified, or some or all
of
the technical features thereof may be replaced with equivalents; and these
modifications or replacements will not cause the essence of the corresponding
technical solutions to depart from the scope of the technical solutions of the
embodiments of the present disclosure.
Industrial Applicability
In summary, the present disclosure provides a process for producing a loose
tube for a totally gel-free fiber optic cable and a device for molding the
same,
by which the loose tube is molded with high quality.
CA 3067014 2020-01-08
