JPH04114110A - In-duct wire passing method for line body - Google Patents

Abstract

PURPOSE:To provide the line body with large travel speed with use of the invariable air blowing force and to improve the travel efficiency of the line body by intermittently opening and closing an air discharge passage provided in front of and nearby the passage for a blast from the rear end of a duct. CONSTITUTION:The air discharge opening 12 provided in front of and nearby the entrance for blown air to the line body 113 is opened abruptly from the closed state. Consequently, the air is discharged from the air discharge opening 12 and the pressure drop becomes abruptly large behind the air discharge opening 12 and the flow velocity of the air in the section increase suddenly. Then the air discharge opening 12 is closed again, and the air which is made fast in flow velocity in the section behind the air discharge opening 12 can not exit from the air discharge opening 12, so the air which is more than that in the stationary state where the air discharge opening is closed flows in a duct 1 before the air discharge opening 12 at high speed although the inflow time is short. Consequently, the line body travels faster than in the stationary state and is sent in the forward duct.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wiring method for drawing a filamentous body such as an optical fiber cable or a wiring wire into a conduit by using an air stream.

[Prior art] In order to lead an electric cable into a conduit laid underground or in a hill, a wiring wire is drawn in advance, or a plurality of sub-pipes are bowed in advance in the conduit, and those sub-pipes are For example, when optical fiber cables are sequentially introduced into a subpipe in response to increased demand, air is sent into the conduit at high speed to introduce filaments with a relatively small weight per unit length. A method called the windsock construction method, in which the filament is drawn in by running on the air current, is sometimes used.

In this method, the viscosity of the blown air gives a propulsive force to the striatum, and by contacting the striatum along its entire length while being blown away, the propulsive force to the striatum is Since the tension is distributed over the entire length of the striatum, the tension applied to the striatum is extremely small compared to the conventional traction method in which the traction tension is applied to the entire length of the striatum. This method is suitable for use in bringing in fiber cables, and currently the striatum is 500 to 1.0
It is designed to be able to be drawn into pipes up to about OO11.

[Problem to be Solved by the Invention 2] The propulsive force per unit length given to the filament by this method is proportional to the pressure drop per unit length of the streamer air, or the longer the lead-in pipe length is, the more the force of the fluid increases. Since the resistance to the flow increases, the air flow velocity decreases, and the propulsive force of the filament is weakened, the pressure near the air inlet may have to be raised to about 10 atmospheres.

In addition, in order to draw the striatum into the above-mentioned duct,
In order to prevent air from leaking backwards, it is necessary to provide a certain amount of sole between the periphery of the striatum and the inlet at the entrance of the striatum, and the frictional force generated by the seal and the flow of air to the rear. It is also necessary to generate a propulsive force to overcome the leakage of air by blowing air, and thus, in order to move the filament, the above-mentioned large blowing pressure is required.

In order to eliminate the frictional force in the seal section mentioned above and prevent the windsock from reducing the propulsive force on the filament, the bobbin around which the optical fiber cable is wound can be rotated into a pressure feeding chamber attached to the rear end of the conduit. It has also been proposed to store and install the cable in a windsock, but even in this case, the air blowing force is considerably shared by the sending force, so the air sending pressure is higher than the air blowing pressure required to run the optical fiber cable itself by the windsock. You have to apply quite a lot of pressure.

[Means for Solving the Problems] The present invention uses an air blower construction method in which, in addition to the propulsive force required to move the filament itself, the force required to send out the filament, and to prevent air leakage to the rear. In order to obtain the propulsion force that overcomes the frictional force at the seal part, the strands can be made to run without having to increase the air pressure at the air outlet so much, or the air blowing pressure at the air outlet should be lower than before. Even with the same pressure, the traveling speed of the filament body can be made even faster. A portion of the air is intermittently exhausted from the air exhaust port, thereby rapidly changing the speed of the air in the section behind the exhaust port.

[Function] If the exhaust port provided in the front near the ventilation inlet for blowing air onto the striatum is suddenly opened from the closed state, the air will be discharged to the outside from the exhaust port. At the rear, the air pressure drop increases rapidly, so the air flow velocity in that section increases rapidly. That is, a large acceleration is applied to the air, and this acceleration provides a large propulsive force to the striatum. This propulsive force is a large force that overcomes the vocal force and frictional force, and is applied to the striatum, albeit for a short time.

Next, when the exhaust port is returned to its original closed state, the air that had been made to flow faster in the section behind the exhaust port will no longer be able to escape from the exhaust port, so the air will be in a steady state when closed. A larger amount of air than the flow rate is flowed into the pipe line ahead of the exhaust port at a high velocity, albeit for a short time. Then, the extra filament f that has been sent out to the rear section is run at a speed faster than the steady state speed, and is sent into the front pipe.

[Example] Referring to the drawings, a method for passing a wire into a conduit according to the present invention will be described. FIG. 1 shows a schematic front view of a wiring line in which a wiring device is installed in the conduit in order to carry out the method of the present invention, and the second rjj! Each figure in J shows a schematic front view of a wiring line showing the state of the filament in each implementation procedure for detailed explanation of the present invention.

First, referring to FIG. 1, the wiring lines used in carrying out the method of the present invention will be described. Reference numeral l denotes a conduit through which the filament is drawn, and is made of polyethylene, steel, etc., for example. Reference numeral 2 denotes a pumping chamber attached to the rear end of the conduit l when viewed in the drawing direction of the filament, and is connected to a through hole 3 that communicates with the conduit l and the through hole 3 from the side. The ventilation passage 4 is provided at the rear end of the filament when viewed in the running direction of the filament.
A compressor 6 filled with compressed air is connected to the air blowing passage 4. Reference numeral 7 designates an intermittently operated exhaust device connected to a portion of the pipe 1 in the front near the pressure-feeding chamber 2; It consists of a solenoid valve 9, a relay 10 that operates the solenoid valve 9 intermittently, and a controller 11 that sets the intermittent operation. Note that the reference numeral 12 in the figure is an exhaust port for exhausting air from the exhaust passage 8 through the electromagnetic valve 9. Reference numeral 13 denotes a filament such as an optical fiber cable or a running wire that is drawn into the conduit l through the knoll portion 5 and through hole 3 of the pumping chamber 2, and is placed at the rear of the pumping chamber 2. It is sent out from the sending out device 14 which has been opened.

The filamentous body 13 is fed out from the feeding device 14, and its tip is inserted forward of the air blowing passage 4 of the pressure feeding chamber 2, preferably into the pipe line l, and the filament 13 is sent out from the compressor 6 to 5 to 1.
Pressurized air of 0 atmosphere is blown into the pipe line 1 through the ventilation passage 4 and the through hole 3.

This air flows out from the front end of the pipe 1, but in the windsock construction method, the filament 13 is carried forward by the flow of air due to the viscosity of this windsock air inside the pipe 1. It is something that can be avoided when driving. At this time, the propulsive force applied to the filament 13 per unit length is proportional to the pressure drop of the air per unit length, and is applied to the entire length of the portion of the filament with which the air comes into contact. The sum of the propulsive forces exerted by the propulsive force, or the force that resists it, i.e., the frictional force caused by the contact of the filament 13 with the inner surface of the conduit l, the filament 1
3 comes into contact with the knoll part 5, the pulling force caused by the filament 13 coming into contact with the backward flow of air leaking from the seal part 5 to the outside, and the pulling force of the feeding device 1.
4, the linear body 13 is caused to travel forward.

In the above-mentioned wiring line, in this invention, an exhaust device that operates intermittently is connected to the position of the forward pipe line l near the pressure-feeding chamber 2, and the air in the pipe line l is intermittently discharged from there. It is.

Next, with reference to FIG. 2, the traveling state of the filament when the exhaust device of the wiring line is operated intermittently will be described. In FIG. 2, the same reference numerals as those used in FIG. 1 indicate the same parts.

Figure (A) shows a state in which the solenoid valve 9 of the exhaust device 7 for the wiring line is closed. Here, the velocity of the air fed into the pipe l on the inlet side is equal to the velocity of the air on the outlet side. Here, a state in which the tip of the filamentary body 13 is located at a position A ahead of the exhaust passage 8 of the exhaust device 7 is shown.

From the above state, the solenoid valve 9 of the exhaust device 7 is suddenly opened, and a part of the air blown from the pressure chamber 2 into the pipe 1 is exhausted through the exhaust passage 8 branched from the pipe 1. Mouth 12
Exhaust from. The state at this time is shown in FIG. Here, when the solenoid valve 9 is suddenly opened from closed, the air is divided into the pipe 1 and the exhaust passage 8, and the resistance to the air is reduced by the amount that is divided into the exhaust passage 8. The air flow velocity behind the passage 8 increases rapidly over a certain short period of time. On the other hand, the flow velocity of the air in the pipe l ahead of the exhaust passage 8 is such that the pressure drop of the air up to the point of the exhaust passage 8 is larger than in the state shown in FIG. 1, and therefore the pressure gradient in the pipe l becomes smaller. Therefore, it decreases.

Here, the above-mentioned increase in the air flow velocity behind the exhaust passage 8 is due to acceleration being given to the air, and the more rapid the increase in flow velocity, the greater the acceleration. A large propulsion force is applied to the body 13, and the filament body is carried by the air with an increased velocity and travels faster than the state shown in FIG. 1, creating a state in which the filament body 13 has slack 14. It will be done.

On the other hand, in front of the exhaust passage 8, the pressure gradient becomes smaller than in the state shown in FIG. It is only necessary to have a driving force sufficient to release this slack, and the burden of the sending force of the filament body, the frictional force of the sealing part, etc. is eliminated, and even though the flow velocity is reduced, the traveling speed of the filament body 13 is Although it may increase somewhat,
The decreasing word is forced to run and reaches a position A, rather than the position traveled in steady state.

If this state continues further, the running speed of the filament 13 will settle down to a speed slower than the state shown in FIG. 1, which is proportional to the flow speed of air ahead of the exhaust passage 8, or preferably, The solenoid valve 9 is closed when the slack 14 created in the striatum 13 changes from increasing to decreasing, or has just entered a decreasing state. The state after this time is shown in the same figure (c), and will be described below with reference to this figure.

In this way, the resistance of the pipe l to air becomes the same as in the state shown in FIG. 1, but the air whose flow rate per unit time is large in the section behind the exhaust passage 8 is immediately The situation is not the same as in FIG. 1, and a larger amount of air than the flow rate in FIG. 1 flows into the pipe line l ahead of the exhaust passage 8, increasing the traveling speed of the filament body 13 in that part. At this time, the flow velocity of the air in the rear part of the exhaust passage 8 decreases toward the state shown in FIG. disappears and becomes the first
It will be in the state shown in the figure. However, as long as there is even a small amount of slack 14 left before reaching the state shown in FIG. Since it is not affected by the force required for this, the frictional force of the seal portion, etc., the filament 13 in that portion is made to run at a faster speed than in a steady state. As a result, even during this operation, the filament 13 is made to travel faster than in the conventional steady state, and is made to travel to position A3, which is further forward than the position reached in the steady state.

After that, as shown in FIG. 1, the solenoid valve 9 is opened again at the same time that there is no slack in the filament 13, or a little earlier than that, and the opening and closing operations are repeated, for example, once. /second cycle.

In the above embodiment, a case was shown in which the exhaust device 7 was connected to the pipe line l located near the front of the pumping chamber 2;
This exhaust device may be connected to the through hole 3 of the pressure chamber 2 and installed at a position of 1 to 3 meters in front of the ventilation passage 4.
degree is preferred, but is not limited thereto.

In addition, although the embodiment has been shown in which air is immediately released into the outside air from the solenoid valve 9 attached to the exhaust passage 8, if a suction pump is connected to the solenoid valve and the air is forcibly sucked, You can easily control the suction power,
Changes in ambient conditions (changes in the force required to pump the striatum,
The amount of air discharged can be adjusted according to changes in blowing pressure, changes in frictional force due to bends in pipes, etc.).

"Effects of the Invention" According to the wiring method of the present invention, by intermittently opening and closing the exhaust passage provided near the front of the air passage from the rear end of the pipe, - At the rear of the exhaust passage, the air flow velocity is suddenly increased, thereby giving a locally large propulsive force to the striated body, and at the same time, in front of the exhaust passage, although the air flow velocity is small, , factors that reduce the propulsive force imparted by the air flow (
The influence of the force required for feeding, the frictional force of the seal part of the pumping chamber, etc.) is eliminated, and the traveling speed increases, and as a result, it is possible to give the filament a large traveling speed with the same blowing pressure as before. Or, the filament can be made to travel with a blowing pressure lower than that of the conventional method, and the running efficiency of the filament with respect to the blowing pressure of air can be further improved.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing one embodiment of a wiring line for carrying out the method of wiring a filamentous body according to the present invention, and each figure in FIG. A schematic front view of the wiring line showing the state of the striatum in each implementation procedure,
Figure (A) shows a state in which the exhaust passage is closed, Figure (B) shows a state in which the exhaust passage is opened, and Figure (C) shows a state in which the exhaust passage is closed again. l; pipe line, 2; pressure feeding chamber, 3; through hole, 4; ventilation passage, 5
Seal part, 6: Compressor, 7: Exhaust device, 8: Exhaust passage, 9: Solenoid valve, 10: Relay ■ No controller, exhaust port, striated body, sending device.

Claims (1)

[Scope of Claims] In a wiring method in which the filamentous body is drawn into the conduit by blowing air into the conduit in which the filamentous body is inserted, the area near the entrance of the blowing air onto the filamentous body; An air outlet is provided in front of the air outlet, and a part of the air blown from the inlet is intermittently discharged from the air outlet to rapidly change the speed of the air in the area behind the outlet. Characteristic method for passing wires through the ducts of the striatum.