JPH0247611A - Device for inserting optical fiber into pipe - Google Patents

Abstract

PURPOSE:To facilitate inserting operation and to improve the operation efficiency by supplying an optical fiber while making pressurized fluid flow into the pipe from its one end, and running the optical fiber in the pipe by flow feeding. CONSTITUTION:The pressurized fluid is supplied to one end of the pipe 1 from an enclosed container 42. The pressurized fluid which is supplied to the pipe flows from one end of the pipe to the other end, and flows through the gap between the internal wall surface of the pipe 1 and the outer peripheral surface of the optical fiber 7 where the optical fiber 7 is present in the pipe 1. Then the optical fiber is applied with a conveying force by the frictional force between the pressurized fluid flowing in the pipe 1 and the outer peripheral surface of the optical fiber 7 and the difference pressure of the fluid across the snaking part of the snaking optical fiber 7. Consequently, even a small-diameter, long optical fiber can be inserted into the pipe 1 by the easy operation and the operation efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a device for inserting an optical fiber into a tube, and more particularly to a device for inserting an optical fiber into a tube using fluid flow.

The optical fiber in this invention includes a fiber wire consisting of a core and a cladding layer, a fiber coated with a synthetic resin, a full bending layer, a ceramic, etc., a single core fiber, a multi-core fiber, and A stranded wire. In addition, pipe refers to steel, aluminum and other metal pipes, and plastic pipes and other non-metallic pipes.

(Prior art) Optical communication cables that have become widely used in recent years are required to be covered with metal tubes because the optical fibers are weak in strength and have poor environmental resistance. It's coming. Among the optical fibers covered by a tube, there is one in which the optical fiber is inserted into the tube by filling a gap (hereinafter referred to as an optical fiber cord).

One method for manufacturing such an optical fiber cord, that is, for inserting an optical fiber into a tube, is a method that utilizes fluid flow. For example, there is a ``method for drawing an optical fiber into a vibrator'' disclosed in Japanese Patent Laid-Open No. 57-29014. In this method, a movable body to which the tip of a traction filament is attached is passed from one end of a tube to the other using fluid pressure. Next, the optical fiber connected to this pulling filament is pulled to draw the optical fiber into the tube.

(Problems to be Solved by the Invention) However, in the conventional method for inserting an optical fiber into a tube, the traction filament is first passed through the tube, and then the traction filament is replaced with an optical fiber. Therefore, the insertion work was complicated and work efficiency was low. Furthermore, since there is a risk that the optical fiber will break during exchange, it is not possible to add a replacement blade that is stronger than the optical fiber to the optical fiber. For this reason, for example, if the outer diameter is 2 mm or less,
It has not been possible to obtain a long optical fiber cord with a diameter exceeding .

Therefore, it is an object of the present invention to provide a device that can insert an optical fiber into a tube with a simple operation, even if the optical fiber cord is small in diameter and long.

(Means for solving the problem) The optical fiber insertion device into a tube according to the first invention includes a closed container;
an optical fiber supply spool disposed within the sealed container;
It consists of an optical fiber feeding device disposed in the sealed container, a pressurized fluid supply source connected to the sealed container, and a metal fitting that connects one end of a tube through which the optical fiber is inserted and the sealed container.

The optical fiber is supplied while flowing pressurized fluid into the tube from one end of the tube, and the optical fiber is inserted into the tube by flow, that is, by the f9 friction force of the fluid applied to the optical fiber and the differential pressure.

The closed container has an opening for inserting and removing an optical fiber supply spool, an optical fiber feeding device, and other devices therein. The opening is closed by a lid. The closed container is filled with a pressurized gas such as air, nitrogen gas, or a pressurized liquid such as water or oil.

The optical fiber supply spool is around which the optical fiber to be inserted into the tube is wound, and is rotatably supported.

It is desirable that the moment of inertia and bearing resistance of the optical fiber supply spool be as small as possible so as not to impede entry of the optical fiber into the tube.

The optical fiber feeding device feeds the optical fiber into the entrance of the tube, and consists of a pinch roll that lightly pinches the optical fiber and a device that rotationally drives it, or a device that rotationally drives the optical fiber supply spool. .

The pressurized fluid supply source supplies pressurized fluid to the closed container, and uses a pressurized gas cylinder, a pump, or the like.

A pipe joint such as a ferrule is used as a connection fitting between the pipe and the sealed container.

A device for inserting an optical fiber into a tube according to a second aspect of the invention includes, in addition to the device of the first aspect, a device for vibrating a tube that cannot be wound into a coiled shape.

To form a coil of tubing, the tubing is wound around a cylindrical body such as a bobbin or spool. In order to vibrate the tube coil, the cylindrical body is driven by a known means such as a vibration motor.

In order to facilitate the passage of the optical fiber into the tube, the frequency of the vibration is 5112 or more, preferably lO to 30Il.
z, total amplitude is 0. I n+n+ or more, preferably 0.5
~2.0 mm. It is desirable that the vibrations have at least a component perpendicular to the optical fiber entering the tube. Note that when the tube coil is also vibrated in the traveling direction of the optical fiber, a conveying force due to the vibration is applied to the optical fiber in addition to the conveying force due to the pressurized fluid.

Note that, at the initial stage of insertion, the optical fiber may not enter the tube due to insufficient conveying force due to the flow. In such a case, the optical fiber is inserted into the tube in advance directly by hand or by mechanical means such as a pinch roll.

This initial insertion creates sufficient transport force for the optical fiber within the tube due to the fluid flow. The length of the initial insertion varies depending on the dimensions of the tube and optical fiber, the surface condition, the pressure of the pressurized fluid, the type, etc., but is generally about several to tens of meters.

(Operation) The optical fiber supply spool with the optical fiber wound thereon is set in the closed container through the opening. Next, the optical fiber is removed from the optical fiber supply spool and the distal end thereof is positioned at the entrance of the tube, or the optical fiber is inserted into the tube for a certain length in advance.

The opening of the sealed container is covered with a lid, etc., and pressurized fluid is supplied to the sealed container. Pressurized fluid is then supplied from the closed container to one end of the tube.

The pressurized fluid supplied to the tube flows from one end of the tube to the other end, and in the portion where the optical fiber is located in the tube, it passes through the gap between the inner wall surface of the tube and the outer peripheral surface of the optical fiber. A conveying force is applied to the optical fiber due to the frictional force between the pressurized fluid flowing inside the tube and the outer circumferential surface of the optical fiber and the differential pressure of the fluid generated before and after the meandering optical fiber undulates.

In addition, in the second invention, due to the force applied to the pipe, the optical fiber jumps from the inner wall surface of the pipe, preventing contact between the two, or causing a sliding state, so that the frictional force acting on the optical fiber from the inner wall surface of the pipe is reduced. becomes smaller. Moreover, this imaging causes undulations in the optical fiber, and a pressure difference in the fluid is generated before and after the undulations. Waviness increases the carrying force of the optical fiber.

(Example) Hereinafter, a device for inserting an optical fiber into a metal tube and a method for inserting the optical fiber into a metal tube will be described.

Figure 1 is '! 1 shows an example of a device for carrying out the invention of tr.1.

As shown in the drawing, the optical fiber insertion device 41 includes a closed container 42, one end of which has an opening 43 covered with a lid 44.
A nozzle 46 is attached to the other end. Inside the closed container 42, a pedestal 48 is fixed to which an optical fiber supply spool 58, an optical fiber feeding device 51, and a guide are attached. Further, a pressure gauge 54 and a relief valve 55 are attached to the closed container 42.

The optical fiber supply spool 58 is supported by the bracket 49 of the pedestal 48 via a ball bearing (not shown). Further, the optical fiber supply spool 58 is detachably attached to the bracket 49 so that it can be replaced through the opening 43.

The optical fiber feeding device 61 is connected to the optical fiber supply spool 5.
8, it is fixed on a pedestal 48. A pair of upper and lower pinch rolls 62 and 63 for lightly pinching the optical fiber 7 are attached to the frame 50 of the optical fiber feeding device 61. The upper pinch roll 62 is movable up and down, and the suppression of the optical fiber 7 is adjusted by an adjustment screw 65. The lower pinch roll 63 is connected to a motor 68 via a belt transmission mechanism 67.
Rotationally driven by.

Pinch roll pair 62, 6: A guide 64 is provided on the exit side of the person 1, respectively.

A fiber detection rod 70 is rotatably attached to the frame 50. The upper end of the fiber detection rod 70 is bent, and the optical fiber 7 is hooked thereon. Further, an upper limit switch and a lower limit switch 72 are attached to the lower part of the frame 50, and the lower end of the fiber detection rod 70 comes into contact with either of these limit switches 71 and 72. There is.

The fiber detection rod 70 detects slack in the optical fiber 7,
The feed speed of the optical fiber 7 is decreased. That is, due to fluctuations in friction between the tube 1 and the optical fiber 7 and changes in fluid pressure, the entrance speed of the optical fiber 7 is not constant. If the entrance speed of the optical fiber 7 is faster than the supply speed, the optical fiber 7 will be pulled backwards and cut, or the entrance will be blocked. On the other hand, if it is slow, the optical fiber 7
There is a risk that it may sag and become tangled within 2, which may obstruct entry.

Therefore, it is necessary that the optical fiber 7 during insertion has an appropriate amount of slack. Therefore, if the slack is too small, the fiber detection rod 70 rotates clockwise and the upper limit switch 71 is activated. As a result, the speed control device
(not shown) increases the rotational speed of the motor 68. Conversely, if the slack is too large, the rotational speed of the motor 68 is reduced.

A cylindrical guide 75 is supported by the stand 51 following the optical fiber feeding device 61 . The tip of the guide 75 is located near the entrance of the nozzle 46 and is tapered. The guide 75 is made of glass to reduce friction with the optical fiber 7.

A nitrogen gas cylinder 78 is connected to the closed chamber 'P342 through an electric stop valve 79 and a pressure regulating valve 80. The nitrogen gas cylinder 78 has a pressure of 150 kgf/cm.
The pressure control valve 80 adjusts the pressure of the nitrogen gas from 150 kgf/cm to 100 kg.
Reduce pressure to gf/cm2.

On the outlet side of the nozzle 46, there is an N, 543 type stop valve 83.
A high-pressure rubber hose 84 is connected through the high-pressure rubber hose 84, and a ferrule fitting 87 is attached to the tip of the high-pressure rubber hose 84 through a stopper 85. The ferrule fitting 87 includes a threaded plug 88, a gasket 89 and a nut 9.
A tube 1 through which an optical fiber 7 is inserted is connected to a high-pressure rubber hose 84 via a ferrule fitting 87. By tightening or loosening the nut 90, the tube 1 can be freely attached to and removed from the high pressure rubber hose 84.

In order to insert the optical fiber 7 into the tube 1 using the above device, first the optical fiber supply spool 58 around which the optical fiber 7 is wound is
the bracket 49 inside the closed container 42 through the opening 43.
Attach to. Optical fiber 7 is connected to optical fiber supply spool 5
8 and pass it through the guide 75 and nozzle 46 between pinch rolls 62.6:1, and open the opening 4 of the closed container 42.
3 with a lid 44. Further, a pipe is connected to the high pressure rubber hose 84 via a ferrule fitting 87. In the case of a short tube of several tens of meters or less, the tube may be stretched in a straight line, but in the case of a long tube, it is wound in a loop or a coil for ease of handling. Next, in order to apply sufficient conveying force to the optical fiber 7 at the beginning of insertion, the optical fiber 7 is placed on a pinch roll 62.about several meters from the tip. [Push it into the tube using i3.

When the preparation for insertion is completed as described above, the electromagnetic stop valve 79 is opened to begin insertion. When the electric six-stop valve 79 is opened, nitrogen gas flows from the nitrogen gas cylinder 78 into the closed container 4.
2 into tube 1. The airtight container 42 has a certain amount of volume! 11), the internal pressure of the container gradually increases. The optical fiber 7 is let out from the sealed volume P:r42 through the nozzle 46, enters the tube 1, and advances inside the tube due to the frictional force and differential pressure acting on the optical fiber 7.

Figure 2 shows an overall view of the second invention, that is, a device for inserting an optical fiber by flowing it while applying vibration to the tube, and
! FIG. 33 is a plan view of the vibration table of this device.

The pedestal 11 is firmly fixed to the floor surface 9 so as not to vibrate. Coil springs 18 for supporting the vibration table are attached to the four corners of the upper surface of the pedestal 11.

A square board-shaped one-liner table 14 is placed on the pedestal 11 via a support spring 18. Vibration table 1
A support frame 15 extends downward from the lower surface of 4.

A pair of photographing motors 21 and 22 are attached to the support frame 15 of the +m shift table 14. The i-shift motor 22 rotates the vibration motor 21 by 180 degrees around the center axis 0 of the vibration table 14 and is in the S position. Further, the IM motors 21 and 22 are in a posture such that their rotation axes are horizontal. The vibration motors 21 and 22 have unbalanced ffl weights (not shown) fixed to both ends of the rotating shaft, and apply vertical force to the vibration table 14 by centrifugal force caused by rotation of the unbalanced weights. That is, the pair of vibration motors 21 and 22 have the same number of prefectures and the same amplitude, and are driven in opposite directions of rotation. Therefore, when the vibrations caused by the pair of vibration motors 21 and 22 are combined, the one-swivel table 14 vibrates up and down.

1 Since the vibration table 14 is attached to the pedestal 11 via the support spring 18 as described above, the vibration table 1
4 is not transmitted to the pedestal 11.

The bobbin 25 is fixed on the rotating table I4 so that the bobbin axis substantially coincides with the center axis C of the vibrating table 14. A tube 1 through which the optical fiber 7 is inserted is wound around the bobbin 25 in a coiled manner, and the optical fiber 7 is supplied into the tube from the lower end of the coil 5 of the tube. In order to avoid applying excessive bending stress to the optical fiber, it is desirable that the diameter of the tube coil 5 is 150 mm or more. In this embodiment, the optical fiber 7 is an optical fiber precoated with resin, and the tube 1 is a steel tube. The outer periphery of the lower flange 27 of the bobbin 25 is designed to receive the vibrations of the vibration motors 21 and 22, respectively.
4 with a fixing jig 30. As shown in FIG. 4, the bobbin 25 has grooves 28 formed by shaver processing in the circumferential direction of the body 26 so that the unevenness is continuous in the bobbin axial direction, so that the tube 1 is in close contact with t1 and 28. It has become. By placing the tube 1 closely in the groove 28 of the body of the bobbin 25 in this way, the movement of the bobbin 25 can be transmitted to the tube 1 with good precision,
It becomes possible to insert the optical fiber 7 smoothly and efficiently.

On the side of the bobbin 25, the same optical fiber insertion device 41 as in the above embodiment is arranged.

Next, a method for inserting the optical fiber 7 into the tube 1 using the apparatus manufactured by JR as described above will be explained.

In advance, the tube 1 is wound in a coil around the bobbin 25 to form the coil 5, and the optical fiber 7, which is a pre-coated fiber wire, is placed in the airtight container 42. Then,
A bobbin 25 around which the tube 1 is wound is fixed on a vibration table 14. Next, the inlet end of the tube and the outlet of the closed container 42 are connected via the ferrule 911 and the outlet 87. At this time,
The tip of the optical fiber 7 is pulled out from the closed container 42 and inserted into the tube entrance. The inlet end 2 is located at the lowest point of the tube coil 5, such that the optical fiber 7 is inserted into the tube 1 along a substantially tangential direction of the tube coil 5.

Next, the electromagnetic stop valve 83 is closed, and the electromagnetic stop valve 79 is opened to prevent nitrogen gas from filling the airtight container 42.

Note that in order for the optical fiber to enter the tube smoothly, a certain amount of clearance is required between the optical fiber 7 and the tube 1, and it is desirable that the clearance be 0.1 ml or more. Furthermore, for similar reasons, the diameter of the tube coil is
It is desirable that the thickness be 150 mm or more, preferably 300 IIIn or more.

Next, when the vibration motors 21 and 22 are driven, since the vibration motors 21 and 22 are attached to the vibration table 14 in the positions and postures described in n1, the one-spindle table 14 vibrates up and down.

When the tap passage preparation is completed as described above, the electro-electric stop valve 83 is opened. Since the electric stop valve 83 is instantaneously fully opened, nitrogen gas flows from the closed container 42 into the pipe at high speed.

As a result, the tip 8 of the optical fiber 7 enters the tube accompanied by this high-speed nitrogen gas.

A conveying force is applied to the optical fiber by the friction force between the nitrogen gas flowing in the tube and the surface of the optical fiber, and by the differential pressure of the fluid generated before and after the undulation of the meandering optical fiber. The vibration applied to the tube 1 causes the optical fiber 7 to bounce off the inner wall surface of the tube, preventing contact between the two, thereby reducing the frictional force acting on the optical fiber from the inner wall surface of the tube. Moreover, this vibration causes waviness in the optical fiber 7, and a pressure difference in the fluid is generated before and after the waviness. Waviness increases the carrying force of the optical fiber. In this way, the tip of the optical fiber 7 reaches the outlet of the tube 1 and the optical fiber is inserted into the tube.

The decrease in nitrogen gas (2) in the sealed container 42 due to the flow of nitrogen gas into the pipe 1 is compensated for by replenishment of nitrogen gas from the nitrogen gas cylinder 78, and the pressure in the sealed container 42 is always 100.
kgf/cm”.

(Product example) An optical fiber was inserted into a steel pipe under the following conditions using the apparatus shown in FIG.

(1) Test material steel pipe coil: outer diameter (inner diameter) is 1. Oa++nφ(0,8
mmφ), length looOm, 1g tube is wound with a barrel diameter of 1200
Steel tube coil wound in line on a mm steel bobbin.

Optical fiber: An optical fiber with a diameter of 0.4n+m, which is a silica glass optical fiber (diameter 125um) coated with silicone resin.

(2) Pressurized fluid: Nitrogen gas with a pressure of 100 kgf/cm (3) Photographing conditions: FA shift count 20 fiz whole prefecture width 1
．． 25 mm (4) Insertion result: Transfer speed 20 m/win Insertion time 50 IIin This invention is not limited to the above embodiments.

The supply of optical fibers into the tube is not limited to just one fiber, but can also include a plurality of fibers depending on the inner diameter of the tube and the diameter of the optical fiber. In the above explanation, we have explained that the optical fiber is pre-coated as a bare wire and the pipe through which the optical fiber is inserted is a steel pipe, but of course, this combination is not limited to this, and there are many other ways such as inserting the optical fiber or its cable into an aluminum pipe, a synthetic resin pipe, etc. Some concrete examples can be considered.

The direction of vibration of the tube coil may be perpendicular to the traveling direction of the optical fiber, in the traveling direction, or in an oblique direction combining both directions. In particular, when the coil of the tube is vibrated so that the bobbin axis and the center axis of the vibration table almost match and any point on the tube moves back and forth along a spiral path, the optical fiber is transported by pressurized fluid. In addition to the force, conveyance force due to vibration is added. In the above example, the tube is wound in a bobbin so that vibrations are reliably transmitted to the coil of the tube, but other means may of course be adopted.

The optical fiber may be fed from the top of the tube coil. The coil posture may be such that the central axis of the coil is horizontal, and the direction of vibration of the coil of the tube may be horizontal. The tube coil can also be excited with an electric vibrator. Also, the pressurized fluid may be air, instead of nitrogen gas.
It may be water or oil.

(Effects of the Invention) According to the device of the present invention, an optical fiber can be inserted into a tube without replacing the traction filament with an optical fiber. Therefore, the insertion work is simple and the work efficiency can be improved.

In addition, since the optical fiber is inserted directly by the flow of fluid, the optical fiber will not break.
It is possible to obtain a long optical fiber cord with a small diameter of less than nun and exceeding 30 m.

Furthermore, since the tube is wound into a coil and the coil of this tube is added, it is easy to handle even a long tube, and the entire tube can be reliably vibrated.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an example of a device for inserting an optical fiber into a tube by iQ feeding, and Fig. 2 is a side view showing an example of a device for inserting an optical fiber into a tube by feeding and one-way movement. 3 is a plan view of one sliding table of the apparatus shown in FIG. 2, and FIG. 4 is a front view showing an example of a bobbin attached to the vibration table. 1...Tube, 5...Tube coil, 7...Optical fiber! 1... Frame, 14... Vibration table, 21.2
2-- Vibration motor, 25... Bobbin, 42... Airtight container, 46... Nozzle, 58... Optical fiber supply spool, 61... Optical fiber feeding device, 7B...
Nitrogen gas cylinder, 79...Electric stop valve, 80...
Pressure control valve, 87...pipe joint.

Claims (2)

[Claims] (1) A device for inserting an optical fiber into a tube using fluid flow, which includes a sealed container, an optical fiber supply spool disposed in the sealed container, an optical fiber feeding device disposed in the sealed container, and the 1. A device for inserting an optical fiber into a tube, comprising: a pressurized fluid supply source connected to a closed container; and a metal fitting that connects one end of the tube into which the optical fiber is inserted and the closed container. (2) A device for inserting an optical fiber into a tube using fluid flow, including a sealed container, an optical fiber supply spool disposed in the sealed container, an optical fiber feeding device disposed in the sealed container, and the A pressurized fluid supply source connected to a sealed container, a metal fitting for connecting one end of a tube through which an optical fiber is inserted and the sealed container, and a device for exciting the coiled tube. Features: Optical fiber insertion device into tubes.