JP3303387B2 - Heating furnace for linear body, apparatus for manufacturing linear body, and method for manufacturing linear body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace for a linear body. More specifically, a heating furnace for heating a linear body by using a heating fluid flowing in a parallel or countercurrent direction to the linear body, for example, a plastic monofilament, a plastic multifilament, a plastic hollow fiber, a plastic optical fiber, glass A heating furnace for performing drawing, heat treatment, and the like of a linear body such as a fiber, a glass optical fiber, and a carbon fiber, a linear body manufacturing apparatus, and a linear body manufacturing method.
Related.

[0002]

2. Description of the Related Art Generally, in such a heating furnace, a heating gas, air, steam, or other inert gas which flows in a direction parallel or countercurrent to a moving direction of a linear body to be heated. Heating the linear body using the heating fluid of
Some processing such as baking, drying, stretching, and heat setting is performed.

Conventionally, in this type of heating furnace, a furnace inlet,
A special non-contact sealing mechanism is provided at the opening of the outlet to minimize the inflow of outside air into the furnace or the outflow of the heating fluid as a heat medium from the furnace, thereby reducing the temperature distribution and flow velocity distribution inside the furnace. As an example of achieving uniformity, there is a heating furnace disclosed in Japanese Patent Application Laid-Open No. Sho 62-238986 previously proposed by the present applicant.

[0004]

However, in the above-mentioned conventional apparatus, the non-contact seal of the heating fluid at the heating furnace inlet and outlet is strengthened to suppress the heating fluid from flowing out of the furnace or the outside air into the furnace. Attempts to make the yarn sway inside the heating furnace or at the heating furnace outlet due to uneven velocity distribution in the width direction at the heating fluid inlet or fluid vibration generated by the collision of the heating fluid blown from above and below the furnace. appear. For this reason, it is necessary to increase the size of the opening of the heating furnace, and as a result, the effect of the non-contact seal cannot be sufficiently exerted. A vicious cycle such as intensification is caused, and there is a problem that the linear bodies come into contact with the inner wall of the furnace or the linear bodies come into contact with each other to cause thread breakage or fusion. This becomes a significant problem when drawing or heat-treating a plastic optical fiber having a low tension of a linear body passing through a heating furnace.

The present invention suppresses the above-mentioned problems, namely, yarn sway at the heating furnace outlet, and eliminates troubles such as yarn breakage and fusion due to contact between the linear body and the inner wall of the heating furnace or between the linear bodies. The heating furnace and the manufacturing equipment for linear bodies can reduce the size of the opening of the heating furnace and reduce the size of the linear bodies.
It is an object of the present invention to provide a method for manufacturing an arrangement and a linear body .

[0006]

The present invention employs the following configuration to achieve the above object. That is, the present invention provides a heating furnace for a linear body that heats a linear body that continuously travels in the furnace by supplying a heating fluid into the furnace. A take-off device for picking up the body is provided, and between the heating furnace and the take-up device, a plurality of air injection holes are connected to the compressed air supply means, and a plurality of air injection holes are formed in the running direction of the linear body. A yarn guide having a cylinder and a vertical wall surface provided on both sides of the air injection hole and an air guide portion formed by a flared opening wall surface continuous with the vertical wall surface is provided. Ma
Further, the apparatus for manufacturing a linear body according to the present invention includes the heating furnace described above.
It is characterized by having. Further, according to the present invention,
The method for producing a body is characterized by using the heating furnace described above.
I do.

[0007]

The operation of the present invention is as follows. When compressed air is sent from the compressed air supply means to the cylinder, air is ejected from an air injection hole formed on the outer peripheral surface of the cylinder. Since the distance between the vertical walls provided on both sides of the air injection hole is relatively small, air flows out at a high speed during this time. However, when reaching the space between the opening walls, the air diffuses and the flow velocity becomes slow. As a result, the linear body is supported in a non-contact manner at the intermediate portion of the air guide portion, and the yarn sway is prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heating furnace according to the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of a heating furnace according to one embodiment of the present invention, and FIG. 2 is a view taken along the line AA-A of FIG. FIGS. 3, 4 and 5 show different embodiments of the yarn guide shown in FIGS. 1 and 2, respectively.
(B) is a cross-sectional view of the yarn guide cut in the running direction of the linear body. FIG. 6 is a configuration diagram when the heating furnace according to the example is used in a plastic optical fiber production line having a core-sheath structure.

In FIG. 1, reference numeral 1 denotes a heating furnace. Heating furnace 1
Has an opening entrance 2 and an opening exit 3 at both ends in the longitudinal direction. The linear body 4 enters the heating furnace 1 from the opening entrance 2, is heated, and is taken out of the furnace from the opening exit 3. Reference numeral 5 denotes a supply roller provided on the opening entrance 2 side, and 6 denotes a take-up roller provided on the opening exit 3 side, for feeding and drawing the linear body 4 into and out of the heating furnace 1. The linear body 4 is stretched by increasing the peripheral speed of the linear roller 4 above the peripheral speed of the supply roller 5. Reference numeral 7 denotes a heat retention heater provided on the inner wall of the heating furnace 1 and is provided to prevent the temperature of the heating fluid from lowering.

8 is a heating fluid inlet, 9 is a heating fluid outlet,
In the present embodiment, the heating fluid flows countercurrently to the traveling direction of the linear body 4. That is, the heating fluid inlet 8 and the heating fluid outlet 9 are provided at positions near the opening inlet 2 and the opening outlet 3 of the heating furnace 1 and are connected to a fluid heating device (not shown). It is circulated and used so as to return to the fluid heating device again through the heating fluid inlet 8, the heating furnace 1, and the heating fluid outlet 9. Reference numeral 10 denotes a seal provided at the opening ends of the opening entrance 2 and the opening exit 3, and provided in a non-contact manner with respect to the linear body 4, thereby suppressing the release of heat in the heating furnace.

At the outlet of the heating furnace, a yarn guide 11 connected to a compressed air supply device 40 is provided. The configuration of the yarn guide 11 will be described with reference to FIG. The thread guide 11
Cylinder 2 supplied with compressed air from one end and closed at the other end
3 is provided. A plurality of air injection holes 26 are formed in the peripheral surface of the cylinder 23 at an angle in a necessary range in the traveling direction of the linear body 4. Are formed at regular intervals. Cylinder 2
3, ring-shaped guide side plates 29 and 30 are fitted at regular intervals with a half-divided gap regulating member 33 interposed therebetween. Opposing surfaces of the guide side plates 29 and 30 are cylindrical 23
The vertical wall surface 31a on the side of the air injection holes 26 group is disposed so as to sandwich the air injection holes 26 group formed on both sides,
A flared opening wall surface 31 connected to the vertical wall surface 31a
b. Then, the opposing guide side plates 29, 30
The air guide portion 32 is formed by the vertical wall surfaces 31a and the opening wall surfaces 31b. The plurality of linear bodies 4 coming out of the heating furnace 1 pass through the respective air guides 32.

As shown by the arrow in FIG.
When the compressed air is sent from 0 to the inside of the cylinder 23, air is ejected from the air injection holes 26 of the cylinder 23. At this time, the air passes through the vertical portion of the air guide portion 32 and enters or exits the opening. During this time, the vertical portion has a small width, so that the moving speed of the air is high. When the air reaches the opening, the air is rapidly diffused and decelerates. Therefore, the linear body 4 is supported in a state of being lifted to a position near the upper end of the vertical portion.

In this case, when the length H of the vertical portion of the air guide portion 32 (that is, the height of the vertical wall surface 31a of the guide side plates 29, 30) is large, the amount by which the linear body 4 rises increases. Generally, about 0.5 to 5 mm is a preferable range. Further, narrow spacing L of the vertical portion, it is possible to float the linear body 4 with a small amount of air.

Further, if the arrangement of the air injection holes 26 is within a narrow range of angles, the linear body 4 can be floated with a small amount of air. That is, in relation to the angle at which the passage direction is changed, it is necessary to arrange the air injection holes 26 over an angle that is about 30 degrees wider than the conversion angle. This means that when the linear body 4 passes through the yarn guide 11, the yarn guide 1
This is to ensure a sufficient floating at the intersection with the thread guide 1. If the sufficient floating is not secured at the intersection with the yarn guide 11, the possibility that the linear body 4 comes into contact at the intersection with the guide increases. This is because levitation in other parts becomes meaningless. Generally, the linear body 4 that has exited the heating furnace 1 travels in a substantially horizontal state until it is cooled and is taken off. Therefore, the angle range of the air injection holes 26 formed in the cylinder 23 is 30 to 60.
Degree is good.

According to the yarn guide 11 shown in FIG. 3, the air guide portion 32 is formed by arranging the guide side plates 29, 30 having the vertical wall surface 31a and the opening wall surface 31b at regular intervals, thereby producing the yarn guide 11. Is extremely easy, and an appropriate device can be easily assembled according to the use conditions. That is, the length H of the vertical portion and the interval L between the vertical portions of the air guide portion 32 can be easily assembled according to the conditions of the linear body 4 to be used.

FIG. 4 shows another embodiment of the yarn guide 11 attached to the heating furnace of the present invention. An air injection hole 27 formed in the cylinder 24 of the yarn guide 11 is a slit-shaped long hole continuous in the cylindrical axis direction. Such air injection holes 27 are juxtaposed in the circumferential direction of the cylinder (the moving direction of the linear body 4). With such a configuration, the guide side plate 2 is provided.
The pitch of the air guide portion 32 can be changed only by changing the width of 9. Further, there is no need to exactly match the position of the air injection hole 27 with the position of the guide side plate 29.

FIG. 5 shows still another embodiment of the yarn guide 11 attached to the heating furnace of the present invention. This thread guide 11
Since the cylinder 25 is made of a porous material such as a sintered body or a wire mesh, it is not necessary to process the air injection holes 28. The gap regulating member 33 regulates the gap L between the vertical portions of the air guide section 32 and also plays a role of preventing air from being blown out from portions other than necessary portions.

FIG. 2 shows a situation in which the heating furnace 1 is separated into upper and lower parts, and the upper side opens the inside of the furnace with broken lines. This means
When setting the linear body 4 in the heating furnace 1, it is very convenient. That is, the linear members 4 in the heating furnace 1 are uniformly arranged at the start of the operation, and it is easy to start the operation with no slack or disturbance between the linear members 4. Even in the case where cuts or the like occur and a part of the linear body 4 accumulates in the heating furnace 1, cleaning of the inside of the furnace becomes easy. Thread guide 11
Is desirably attached to the lower side of the heating furnace 1, that is, the outlet on the fixed side.

FIG. 6 shows an example in which the heating furnace of the present invention is used in a production line for a core-sheath fiber such as a plastic optical fiber. 12 is a base. Gear pumps 13, 14
Polymer sent from the base 12 through the core-sheath fiber 18
Is discharged. The gear pump 13 has a sheath component polymer 1
5 and a core component polymer 16 are supplied to the gear pump 14. Cooling air 17 is applied to the discharged core-sheath fiber 18.
Is applied, cooled and picked up by the transaction roll 19.
Subsequently, the core-sheath fiber 18 is drawn at a predetermined magnification between a take-up roll 19 and a draw roll 20, further drawn by a heat treatment roll 21, and finally wound around a bobbin 22.

During these steps, when the core-sheath fiber 18 is stretched between the take-up roll 19 and the stretching roll 20, the heating furnace 1 is used to heat the fiber being stretched so as to perform smooth stretching. You are using The heating furnace 1 is also used when the fiber is stabilized by heat treatment while keeping the peripheral speeds of the drawing roll 20 and the heat treatment roll 21 constant. In any case, the core-sheath fiber 18 that has exited the heating furnace 1 is in a very high temperature state, and the heating furnace 1 and the drawing roll 20 or the heat treatment roll 21 need to be sufficiently separated. because,
This is because if the fiber exiting the heating furnace 1 is not sufficiently cooled and comes into contact with a roll or the like, surface flaws or fiber crushing may occur. Particularly, in the case of a core-sheath fiber such as a plastic optical fiber, a surface flaw is generated. In other words, this leads to a serious defect of deterioration in light transmission due to light leakage.

When the fiber is run with the drawing roll 20 or the heat treatment roll 21 sufficiently separated from the outlet of the heating furnace 1, the point where the fiber is supported becomes very far away, and the heating fluid in the heating furnace 1 Large thread sway occurs due to turbulence in the flow or fluctuation in the tension of the fiber. In the heating furnace of the present invention, the non-contact yarn guide 11 is provided at the outlet, whereby the yarn sway is restricted, and the core-sheath fiber 18 and the inner wall of the heating furnace due to the yarn sway are contacted with each other or between the core-sheath fibers. Troubles such as surface scratches, fusion, and thread breakage due to contact can be eliminated. Further, since the yarn sway at the heating furnace outlet is reduced, the opening of the heating furnace can be made smaller.

A specific example in which the heating furnace according to the present invention is used for drawing a plastic optical fiber will be described. The heating furnace used was the heating furnace shown in FIGS. 1 and 2, and the total length was 3 m. The yarn guide 11 had the structure shown in FIG. 3 and was provided at a distance of 15 cm from the heating furnace outlet. The diameter of the cylindrical portion 23 of the thread guide 11 is 26 mm, the interval L between the vertical portions is 0.8 mm, and the length H of the vertical portion is 1.5 mm.
0.8 mm diameter air injection holes 26 within a range of 60 degrees around 3
Were provided at nine locations, and compressed air having a pressure of 0.2 MPa was supplied into the cylinder 23.

As the linear member 4 to be processed, a plastic optical fiber having a core-sheath structure was used. As a core component, a radical reaction initiator and a chain transfer agent are added to sufficiently purified commercially available methyl methacrylate to perform continuous bulk radical polymerization, and then monomers and the like are removed by a demonomerization machine comprising a uniaxial vented extruder. Has a weight average molecular weight of 830
A polymethyl methacrylate having a residual monomer ratio of 0.22% by weight was obtained and used. A commercially available fluorinated methacrylate was used as the sheath component.

The core component and the sheath component are continuously supplied at 250 ° C.
To obtain a 707 μmφ undrawn plastic optical fiber. Subsequently, the non-stretched plastic optical fiber was non-contact heat-stretched 2.0 times while being heated to 160 ° C. using a heating furnace of a hot air circulation system as described above,
Further, dimensional stability was improved by performing a constant-length heat treatment while heating to 165 ° C. in the same heating furnace, and winding was performed using a constant-tension winding machine to obtain a drawn plastic optical fiber having a diameter of 500 μmφ. The yarn sway at the heating furnace outlet at this time was measured and found to be a very small sway that fits within a circle having a diameter of 5 mm.

<Comparative Example> A drawn plastic fiber was manufactured under the same conditions as in the example except that the yarn guide 11 was not attached to the outlet of the heating furnace. When the yarn sway at the outlet of the heating furnace at this time was measured, it was a very large sway that reached a circle having a diameter of 25 mm.

[0026]

According to the present invention , a heating furnace for a linear body and a linear body according to the present invention are provided.
The production apparatus and the method for producing a linear body according to the present invention have the following excellent effects by providing a yarn guide capable of guiding the linear body in a non-contact manner at the outlet of the heating furnace as described above.

(1) Troubles such as thread breakage, fusion, and scratches on the surface of the linear body due to the linear body coming into contact with the inner wall of the furnace and the contact between the linear bodies due to the reduced vibration of the linear body. Disappears.

(2) The distance between the fulcrum points of the linear body can be reduced, the droop of the yarn in the furnace can be reduced, and the height inside the furnace can be reduced.

(3) Since the height of the yarn at the outlet of the heating furnace is regulated together with the reduction of the swaying of the linear body, the size of the furnace opening can be reduced, and the blowing of the heating fluid to the outside can be reduced. Energy saving.

(4) Since the linear body is cooled by the air blown out from the yarn guide, the cooling time after leaving the heating furnace is shortened, and the distance between the heating furnace and the take-up roll can be shortened. Installation space can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a heating furnace according to an embodiment.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3 is an embodiment of a thread guide, in which (a) is a cross-sectional view of a main part in which the thread guide is cut in an axial direction, and (b) is a cross-sectional view in which the thread guide is cut in a running direction of the linear body.

4A and 4B show another embodiment of the yarn guide, wherein FIG. 4A is a cross-sectional view of a main part of the yarn guide cut in the axial direction, and FIG. 4B is a cross-sectional view of the yarn guide cut in the running direction of the linear body. .

5A and 5B show another embodiment of the yarn guide, wherein FIG. 5A is a cross-sectional view of a main part obtained by cutting the yarn guide in the axial direction, and FIG. 5B is a cross-sectional view of the yarn guide cut in the running direction of the linear body. .

FIG. 6 is a configuration diagram when the heating furnace according to the example is used in a plastic optical fiber production line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heating furnace 2 ... Opening inlet 3 ... Opening outlet 4 ... Linear body 5 ... Supply roller 6 ... Take-off roller 7 ... Heating heater 8 ... Heating fluid inlet 9 ... Heating fluid outlet 10 ... Seal 11 ... Thread guides 23, 24, 25 ... Cylinder 26,27,28 ... Air injection hole 29,30 ... Guide side plate 31a ... Vertical wall surface 31b ... Opening wall surface 32 ... Air guide part 33 ... Space regulating member 40 ... Compressed air supply device

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI D06B 23/16 D06B 23/16 (56) References JP-A-60-9918 (JP, A) Utility model registration 2516992 (JP, Y2) 1-30947 (JP, B2) JP 6-102867 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F27B 9/28 B29C 35/06 D01F 9/32 D02J 1 / 22 301 D02J 13/00 D06B 23/16

Claims (6)

(57) [Claims] 1. A linear heating furnace for heating a linear body running continuously in a furnace by supplying a heating fluid into the furnace, wherein the linear body is provided at an outlet side of the heating furnace. A cylinder having a plurality of air injection holes formed between the heating furnace and the take-up device, the communication device being connected to a compressed air supply means, and having a plurality of air injection holes formed in a running direction of the linear body. And a yarn guide having a vertical wall surface provided on both sides of the air injection hole and an air guide portion formed by a flared opening wall surface continuous with the vertical wall surface. heating furnace. 2. The heating furnace for a linear body according to claim 1, wherein the air injection holes provided in the cylinder are elongated holes continuous in the longitudinal direction of the cylinder. 3. The heating furnace for a linear body according to claim 1, wherein the cylinder is a porous body. 4. The gap between the vertical wall surfaces is determined by the thickness of the gap regulating member.
A heating furnace for a linear body according to any one of the above. (5) According to any one of claims 1 to 4
An apparatus for manufacturing a linear body, comprising: 6. According to any one of claims 1 to 4
A method for producing a linear body, wherein the heating furnace is used.