JPH089688Y2 - Jelly filling device for optical fiber core wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] This invention is a so-called loose tube optical fiber in which one or more optical fiber core wires are loosely inserted in a plastic tube and filled with jelly. The present invention relates to a filling device for a core wire jelly.

[Prior Art] When a fiber is exposed to moisture or pressure is applied, the fiber strength may be reduced or the optical transmission characteristics may be deteriorated. There is one in which one or more optical fiber cords are loosely housed and filled with jelly.

Such a loose tube optical fiber core is manufactured by, for example, extruding a plastic such as polybutylene terephthalate (PBT) tube loosely around the optical fiber core, and at the same time, for example, an olefin oil-based jelly in the tube. The loose space is filled by injection.

This type of jelly has a high consistency of about 400 at room temperature and a viscosity of about 1 to 2 × 10 ⁵ cps.
However, if air bubbles are present in the jelly, the air bubbles will expand due to exposure to a higher extrusion temperature of the tube in the extruder, causing the tube in that part to inflate, and vice versa. As a result, the jelly is not locally filled, and the bubbles shrink when cooled, and the tube in that area becomes thin, resulting in a poor appearance of the tube.

In order to prevent the appearance defect of the extrusion tube due to the presence of air bubbles in the jelly, it is conventionally vacuumed to defoam it before injecting and filling the jelly, or the jelly is heated to reduce its viscosity. A method of promoting defoaming is adopted.

[Problems to be solved by the invention] However, such a defoaming method has a consistency of about 400,
Even if vacuum degassing is performed on a jelly having a viscosity of about 1 to 2 × 10 ⁵ at room temperature, it takes a long time of about 5 to 6 hours to sufficiently remove the bubbles in about 50 l of jelly, The defoaming process could not be done online with the jelly filling process, and a separate process was inevitable.

Also, although jerry is usually received in drums, as mentioned above, due to the high viscosity of jerry, a pump with a high output is required to suck it up, but the amount of jerry to be supplied to the extruder is Since it is a small amount of 50 to 200 cc / min, it is not possible to control such a small amount with the above-mentioned high output suction pump, and once the jerry is transferred from the drum to the small tank, the jerry's own weight is used. Therefore, a transfer process of supplying a fixed amount with a small pump was required.

[Means for Solving the Problems] The jelly filling device of the present invention is an on-line device for performing the above defoaming process with the jelly filling device connected to the extruder of the tube, and from suction from the jelly supply source to the extruder. The first pump that sucks the jelly from its supply source and pressurizes and sends it to the defoaming device, and the bubbles in the jelly sent out from the first pump. And a defoaming device having a degassing hole for degassing, are connected to a second pump for supplying jelly to the extruder of the tube, and the discharge amount of the first pump is larger than that of the second pump. It is the one.

[Operation] Between the supply source of the jelly and the second pump for supplying the jelly to the tube extruder, the jelly is sucked from the supply source and pressurized and sent to the defoaming device, rather than the discharge amount of the second pump. By providing a large first pump, the internal pressure between the pumps rises, and the excess jerry of the difference in the discharge amount of both pumps overflows from the deaeration holes of the defoaming device and enters the defoaming device. When the air bubbles contained in the air are suspended at the entrance of the degassing hole, they are removed from the degassing hole together with the jelly.

Further, by connecting and installing two pumps, a first pump for sucking up jelly from the jelly supply source and a second pump for feeding jerry to the extruder,
The part requiring high output for siphoning is contracted to the first pump, and the part requiring a small amount of quantitativeness for supplying to the extruder is contracted to the second pump.

[Embodiment] An embodiment of the jelly filling apparatus of the present invention will be described with reference to the drawings.

First, referring to FIG. 1, this is an embodiment in which the jelly filling device of the present invention is connected to a jelly supply source, from which jerry is sucked and sent under pressure to the tube extruder shown in FIG. In a side view of a partial cross section, 10 is a jelly supply source, for example, a drum in which jelly is stored,
11 is a jelly, 1 is a jelly filling device of the present invention, which comprises a first pump 2, a defoaming device 3 and a second pump 4,
The discharge amount of the first pump 2 is set to be larger than that of the second pump 4, and is connected to the jelly supply source 10 in the above order. Reference numeral 5 is their connecting pipe. The defoaming device 3 has a degassing hole 6, from which the jelly 11 is sent to the second pump 4 and, at the same time, discharged from the degassing hole 6.

The jelly 11 in the supply source 10 is sucked by the first hoop 2 and is pressurized and sent to the defoaming device 3. The discharge amount of the first pump 2 is set to be larger than that of the second pump 4, and the jelly 11 is in a pressurized state in the defoaming device 3 between the pumps. An extruder 20 fed to the second pump 4 and shown in FIG. 2 described later.
At the same time as the gas is supplied to the degassing holes 6, the degassing holes 6 overflow together with the bubbles contained therein.

In the above, the jelly 11 overflowed from the degassing hole 6 for defoaming may be returned to the drum 10 which is the supply source 10 and reused. Further, since the amount of jelly filled in the loose tube extruded is as small as 50 to 200 cc / min, a high precision one is required as the second pump 4 for transferring jelly to the extruder, Since the supply of the jelly 11 from the supply source 10 is contracted to the first pump 2, it is not necessary to select a high output pump as the second pump 4, and it is possible to secure quantitativeness and to some extent the fluctuation of the source pressure. Therefore, it is possible to select a gear pump that is suitable for use when the discharge amount hardly changes.

The jelly discharged from the second pump 4 of the jelly filling device 1 is transferred to the extruder 20 shown in FIG. Hereinafter, the manufacturing of the loose tube optical fiber core wire will be described with reference to FIG. 2. A jelly filling jig 21 is connected and installed at the rear end of the extruder 20 and penetrates the extruder 20 from the rear side thereof. Books or more optical fibers 31 are run. In the figure, 5 is a pipe connecting between the second pump 4 shown in FIG. 1 and the above-mentioned jelly filling jig 21. 22 is a hopper for supplying a tube material such as PBT to the extruder 20 by a chip, 23 is a die provided at the tip of the extruder 20, 24 is a nipple provided inside the die 23, and 25 is further inside thereof The optical fiber 31 is run at the center of the optical fiber nip 25 provided at the same time, and at the same time, the extrusion coating 32 of the fiber jelly 11 is provided around the optical fiber 31.
Is formed. Then, the tube material 33 is extruded from between the die 23 and the nipple 24, and the optical fiber cord 31
A tube 34 is formed on the outer periphery of the extrusion coating 32 of the jelly around the outer periphery of the tube, and the loose tube optical fiber core wire is formed.
35 are composed. After that, the core wire 35 is the cooling water tank.
It is inserted into 26 and cooled to complete the loose tube optical fiber core 35.

The deaerating action in the above is performed by the jelly 11 in the defoaming device 3.
When the portion of the bubbles present inside the degassing hole 6 reaches the inlet of the degassing hole 6, the bubble enters the degassing hole 6 and is discharged to the outside, and the bubbles that pass without touching the opening are not discharged. However, when the jelly 11 moves through the connection pipe 5 and inside the defoaming device 3, bubbles seem to flow through the center part where the flow velocity is the fastest, and the jelly 11 is always overflowed from the degassing hole 6. However, since the bubbles seem to be selectively discharged rather than the jelly 11 when passing through the vicinity of the deaeration hole 6, as in the embodiment shown in FIG. It is desirable that the pipe as a through hole penetrates through the pipe wall of the defoaming device 3 and is projected inside, and it is particularly desirable to project the entrance of the pipe of the degassing hole 6 to the vicinity of the center. As for
Instead of projecting into the inside of the tube wall, it may simply project from the tube wall to the outside.

As described above, when the inner diameter of the defoaming device 3 is too large, many bubbles pass without touching the inlet of the degassing hole 6,
If the inner diameter is too small, the passage speed of the jelly 11 will be so high that even if bubbles come into contact with the inlet of the degassing hole 6, they will be allowed to pass before they reach the inlet.

The size of the bubbles that enter the defoaming device 3 depends on the defoaming device 3
If the inner diameter is 15 mmφ, there are about 15 mmφ × 10 to 20 mm, and such bubbles of course cause fatal appearance defects in the extruded loose tube, but on the contrary, the size of the bubbles that do not result in appearance defects is It has been experimentally confirmed that the diameter is about 1 mmφ or less.

Therefore, the inner diameter of the defoaming device 3 is determined by the size of bubbles to be degassed, but when removing bubbles with a diameter of 1 mm or more, the inner diameter of the defoaming device 3 is 5 to 20 mm. The degree is desirable.

As an experimental example, the inner diameter of the defoaming device is 15 mm, and the inner diameter of the deaeration hole is
1 mm, the discharge rate of the second pump 65 cc / min, the defoamer internal pressure 3 ± 0.5 kg / cm ² was fed to the extruder, and the inner diameter was supplied.
As a result of extruding a 1.5 mm loose tube, all bubbles with a relatively large diameter of 1 mm or more that would cause problems when extruding were removed, and the appearance of the extruded loose tube was 2.5 ± 0.1 mm in outer diameter. A tube equivalent to the method, that is, the method of sufficiently removing the air bubbles in the tank and the subsequent extrusion was obtained.

[Advantage of the Invention] According to the jelly filling device of the present invention, the defoaming device having a degassing hole between the first pump for sucking up jelly from the jelly supply source and the second pump for feeding to the extruder. Since the discharge amount of the first pump is made larger than the discharge amount of the second pump, the jelly sent from the first pump to the defoaming device is sent to the second pump from there and at the same time, Large air bubbles that overflow with the contained air bubbles from the degassing holes and interfere with the extrusion of the loose tube in the jelly are discharged and removed.

Also, sucking up jelly from the jelly source,
The feeding of the jelly to the extruder was performed by using two separate pumps, the first pump for sucking up and the second pump for feeding, so for the precise quantitative feeding for extrusion. , Transferring the jelly from a drum to a small tank and sending it with a small pump using its own weight, it does not require a transfer process, from suction of the jerry to the supply to the extruder in one step As a result, it has become possible to significantly improve the productivity of the optical fiber core wire by adding the de-foaming step of Jerry to the manufacturing process of the loose fiber optical fiber core wire.

[Brief description of drawings]

FIG. 1 is a side view of a partial cross section showing an embodiment in which the jelly filling device of the present invention is connected to a jelly supply source, and FIG. 2 is a loose tube optical fiber in which jelly is fed from the jelly filling device. It is a side view of the partial cross section which shows the Example of the extruder for manufacturing a core wire. 1; jelly filling device, 2; first pump, 3; defoaming device, 4; second pump, 5; connecting pipe, 6; degassing hole, 10; jerry supply source, 11; jerry, 20; extruder, 21 ; Jerry filling jig, 2
2; Hopper, 23; Die, 24; Nipple, 25; Jelly Nipple, 26; Cooling water tank, 31; Optical fiber core wire, 32; Jerry coating, 33; Cube material, 34; Cube, 35; Loose tube Optical fiber Core line.

Claims (1)

[Scope of utility model registration request] 1. A first pump for sucking jelly from its supply source and feeding it under pressure to a defoaming device, and a defoaming device having a degassing hole for degassing bubbles in the jelly sent from the first pump. A second pump that supplies the jelly discharged from the defoaming device to the extruder of the tube, and the discharge amount of the first pump is made larger than that of the second pump. Jelly filling machine