JP2855741B2 - Configuration method of optical distribution network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention uses a predetermined pumping device to pressurize an optical fiber cable (including an optical fiber unit) into a tube with a compressed gas, and extends over a multilayer floor. The present invention relates to a method for configuring an optical distribution network for connecting an optical fiber cable to an optical information processing apparatus disposed.

[Conventional technology]

A method of passing an optical fiber cable through a tube using airflow was developed by Telecom of the United Kingdom, and a paper entitled "The Blown Fiber Cable" (IEEE Jo
urnal on Selected Areas in Communications, Vol.SAC
-4, No. 5, August 1986) pp. 679-685). In this paper, when pumping an optical fiber cable in the horizontal direction using airflow, the effective pumping force, which is obtained by subtracting the frictional force with the tube inner wall from the pumping force generated in the optical fiber cable by the airflow, is the pressure drop in the tube. There is a theoretical study that if the value is constant, the value becomes constant in the longitudinal direction, and thus increases in proportion to the insertion length of the optical fiber cable. In this case, the pumping force f per unit length generated in the optical fiber cable by the air flow is the outer radius r _{1 of the} cable,
If the inner radius of the tube is r ₂ and the coefficient (dP / dL) represents the gradient of the pressure drop in the tube, it is expressed by the following equation.

f = π × r ₁ × r ₂ × (dP / dL) (1) In the above paper, the slope of the pressure drop is assumed to be constant in the longitudinal direction of the tube, so that equation (1) can be expressed as follows. Can be

f = π × r ₁ × r ₂ × (P / L) (2) In this case, the pumping force f per unit length does not depend on the insertion length of the optical fiber cable into the tube and the distance from the tube entrance. , R ₁ , r ₂ P, L, and is always constant in the longitudinal direction of the optical fiber cable.

In addition, when a climbing portion is included in the wiring path, the weight of the optical fiber cable inserted into the tube becomes a resistance to the pumping force due to the air flow, and the resistance due to the weight of the cable and the distance between the optical fiber cable and the inner wall of the tube. The pumping state is determined by whether or not the sum of the frictional force and the frictional force is larger than the pumping force. Accordingly, r ₁ , r ₂ , and r _{1 are set} such that the pumping force f per unit length is larger than the sum of the resistance force and the friction force.
If P and L are set, the optical fiber cable can be inserted and laid along the entire length of the tube. In this case, it does not depend on the distance from the tube entrance of the climbing portion or the insertion length of the optical fiber cable into the tube.

[Problems to be solved by the invention]

However, in reality, the pumping speed of the optical fiber cable decreases as the distance of the cable passing through the tube increases, and in the worst case, the optical fiber cable sometimes stops in the middle of the tube. In the above-mentioned paper, it is stated that the measured value of the tension of the optical fiber cable inserted by the airflow does not match the value obtained by the theoretical study, and that the theoretical study does not always represent the reality.

Also, when there is an ascending portion in the wiring path, the state of the change in the pumping speed varies depending on the distance from the tube entrance, and it is considered that the pumping force per unit length of the optical fiber cable is not uniform in the longitudinal direction. For this reason, when a tube is provided in a wiring path including a climbing portion, it may not be possible to insert and lay an optical fiber cable in the tube using an air flow.

In this case, the wiring route is divided into short portions to insert and lay the optical fiber cable so that the pressure can be reliably fed by the conventional laying method, and the optical fiber cable longer than the route is extended at the exit of the split wiring route. Once wound, the wound optical fiber cable was inserted and laid in the next tube using an air flow. Therefore, it is necessary to repeat the insertion, laying and winding operations, and there is a disadvantage that workability is poor.

Also, at the expense of the transmission characteristics of optical fiber cables,
Many connection parts of the optical fiber cable were provided.

Accordingly, an object of the present invention is to improve workability when configuring an optical wiring network.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention provides an optical wiring system for feeding an optical fiber cable into a tube with a compressed gas by using a pumping device and connecting the optical fiber cable to an optical information processing device arranged over a multilayer floor. A method of constructing a network,
In advance, based on the propulsion force in the state where insertion becomes impossible by gradually reducing the propulsion force when the optical fiber cable is pressure-fed to the ascending portion of the tube, the length of the optical fiber cable at the ascending portion is reduced. The resistance force is calculated as a function, and at each point on the tube installed to place the optical information processing device on a series of wiring paths, the propulsive force per unit length given to the optical fiber cable by the compressed gas is:
It is characterized in that the wiring path of the optical fiber cable or the gauge pressure of the pumping device is set to be greater than at least the resistance per unit length when the optical fiber cable is inserted into the tube.

[Action]

The limiting conditions for inserting and laying the optical fiber cable into the tube are the propulsion force (pumping force) acting on the optical fiber cable, the friction between the inner wall of the tube and the optical fiber cable, and the optical fiber cable generated at the climbing part. Is determined by the resistance force of its own weight.

The propulsive force acting on the optical fiber cable is expressed by equation (1), but for (dP / dL) in the equation, the pressure is found to decrease uniformly according to an upwardly convex curve (Research Report, Vol. 89, No. 32, pp. 61-66). Therefore, it is theoretically estimated that the closer to the outlet of the tube, the greater the slope of the pressure drop and the greater the propulsive force per unit length of the optical fiber cable. This driving force does not depend on the wiring route of the tube, and is constant as long as the inner diameter of the tube and the outer diameter of the optical fiber cable are not changed.

On the other hand, the resistance force when the optical fiber cable is inserted into the tube is determined by the weight and friction of the optical fiber cable, and the value is experimentally calculated.

Built this resistance altitude difference 2~45m to determine the R, tube length 100～800M (Bore 6 mm ^phi) conditions at different elevations difference, the route that combines tube length, outer diameter
The propulsive force required for insertion was measured by a tensiometer arranged at each point in the tube while an optical fiber cable having a ^diameter of 2 mm was inserted using an air flow. Since the resistance R is equal to the thrust in the state where insertion becomes impossible because the thrust of the optical fiber cable is gradually reduced, the own weight m and the frictional force fμ of the optical fiber cable at the climbing portion are obtained. The sum of the force acting in the direction opposite to the propulsive force (m + fμ) minus the tension fT from the beginning of the ascending portion to the end of the ascending portion when the insertion becomes impossible is the total resistance force _{R R} at the ascending portion. Become. That is, the resistance R per unit length at the climbing portion is R = F _R / H = m / H
+ Fμ / H−f _T / H. Here, m / H is the weight of the optical fiber cable per unit length, and fμ / H is the friction force per unit length. fμ / H is obtained by measuring the tension when the optical fiber cable starts to move when the optical fiber cable starts to move when the optical fiber cable is inserted into the horizontal route and when the optical fiber cable does not contact the inner wall of the tube. . FIG. 8 shows the principle. (A), (b)
In both cases, the conditions such as the tube diameter, tube length, air pressure, and optical fiber cable are the same, and the only difference is whether the optical fiber cable and the inner wall surface of the tube are in contact between the tensiometers A and B. Assuming that the tension measured by the tensiometer A is T, T becomes equal to both (a) and (b). Assuming that the propulsive force generated in the optical fiber cable between A and B is t and the frictional force is fμ, the tension measured by the tensiometer B in (a) is T + t−
In the case of fμ and B of (b), T + t is obtained, and the frictional force fμ can be determined from the difference. Further, f _T is measured directly by the tension calculation during route through including climbing the.

For example, under various conditions of an experiment in which an optical fiber cable (inner diameter 2 mm, own weight 2 g / m) is inserted into the ascending portion of a tube (inner diameter 6 mm), the height H at which the optical fiber cable could be climbed, The relationship with the resistance R acting per unit length of the optical fiber cable at the portion was determined. When the relationship between H and R was determined as a linear regression equation based on the experimental results, the resistance R was Indicated by This equation shows that the longer the vertical climb, the greater the resistance per unit length. This is presumed to be because the effect of the propulsion force from the front of the climbing portion becomes relatively small.

In principle, the resistance R is the sum of the cable's own weight and the frictional force 2.
It cannot be larger than 34 (g / m), and becomes constant when H is 36.3 m or more.

Therefore, by comparing these values with each other and setting the wiring path so that the propulsive force exceeds the resistance at each point of the tube, it is possible to avoid stopping in the middle of the tube of the optical fiber cable.

〔Example〕

Hereinafter, a method for configuring an optical distribution network according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the description, the same elements will be denoted by the same reference symbols, without redundant description.

1 to 4 show an embodiment and an application example of the present invention. FIG. 5 is an example of an arrangement of an optical information processing apparatus, FIG. 6 is a structural example of a pumping apparatus, and FIG. 7 is a pumping apparatus. FIG. 3 shows the propulsion force per unit length given by the compressed air supplied from. First, the characteristics of the pumping device according to one arrangement example will be described with reference to FIGS. In this embodiment, the optical information processing devices A, B,
C and D are arranged, and ducts 1 and 2 obtained by laying tubes for laying optical fiber cables are installed on both sides of the building in a vertical direction at a horizontal interval of 50 m. The height up to the floor above the first floor is 10 m (see Fig. 5). The installation start point E of this building is arranged below the duct 1. The laying start point E is connected to a pressure feeding device 3 for feeding the optical fiber cable with compressed air.

As the pressure feeding device 3, a device in which drive wheels 3b and 3c are incorporated in a feed head 3a together with a compressed air injection port 7 (Japanese Patent Application Laid-Open No. Sho 59-104607, entitled "The Blown Fiber Cable") IEEE
Journal on Selected Areas in Communications, Vol.S
AC-4, No. 5, August 1986) pp. 679-685) can be used (see FIG. 6). In this pumping apparatus, the optical fiber cable 4 is stored in a state of being wound on a supply reel 5 in advance, and has a sufficient force to overcome the hydrostatic potential.
It is guided from 3d by drive wheels 3b and 3c composed of rubber rollers, and supplied along the tube 6.

Fig. 7 shows the propulsion force per unit length generated at each point when a gauge pressure of 8 kg / cm ² was applied at the tube entrance and the optical fiber cable 4 having an outer diameter of 2 mm was inserted into a total length of 300 mm of a tube having an inner diameter of 6 mm. It shows. A curve indicating this propulsion (hereinafter referred to as a “propulsion line”) is specified by the outer diameter of the optical fiber cable, the inner diameter of the tube, the total length, and the pressure of the compressed gas supplied to the tube (pressure at the tube inlet). You. The propulsive force per unit length increases in a quadratic curve with respect to the distance from the tube entrance as shown in FIG.

In the method of constructing an optical distribution network shown in FIG. 1, one continuous tube is erected along a path shown by a broken line in FIG. 1A, and an optical fiber cable is laid in the tube. First, it is vertically pumped along the duct 1 from the installation start point E to the third floor. As shown in FIG.
The resistance required for the climb to the floor is less than the propulsion generated by the compressed air. However, when pumping up to the fourth floor, the resistance exceeds the propulsion. Therefore, it is clear that by propelling the optical fiber cable vertically to the third floor and then horizontally in the third floor, the propulsive force exceeds the resistance as shown in FIG. Yes, and an optical fiber cable can be connected to the optical information processing apparatus B on the third floor. Next, the optical fiber cable is passed through the vicinity of the optical information processing device B and advanced to the duct 2, and the duct 2
Through the 3rd floor to the 4th floor. Since the resistance in this case is relatively smaller than the propulsion, the optical fiber cable can be pumped at a higher speed. On the fourth floor, the optical fiber cable is pressure-fed so as to pass near the optical information processing apparatus C arranged on this floor. Next, it is pumped through the duct 1 from the fourth floor to the sixth floor. The resistance in this case is from the first floor to 3
Although the resistance is equal to the resistance when pumping to the floor, the difference between the propulsion and the resistance is large because the propulsion is increasing in a quadratic curve, and the optical fiber cable is pumped at a higher speed. The optical fiber cable is the optical information processing device D on the 6th floor.
After passing through the vicinity of the first floor, it is pressure-fed to the first floor through the duct 2, passes through the vicinity of the optical information processing apparatus A on the first floor, and reaches the laying start point E. As described above, after the optical fiber cable is laid in the tube installed along the path indicated by the broken line in FIG. 1A, the optical fiber cable in the tube is placed at each position of the optical information processing devices A to D. The necessary optical fiber is taken out from the optical information processing device and connected to each optical information processing device, thereby completing the wiring.

As described above, when the gage pressure of the propulsion line, that is, the gauge of the pumping device is set in advance, the optical fiber cable can be reliably pumped by setting the wiring route so that the resistance is always lower than the line. .

In the method of constructing the optical distribution network shown in FIG. 2, one continuous tube is erected along a path shown by a broken line in FIG. 2A, and an optical fiber cable is laid in the tube. First, the optical fiber cable is horizontally fed from the installation start point E to the duct 2 through the vicinity of the optical information processing apparatus A, and then the optical fiber cable is vertically sent along the duct 2 to the third floor. In this case, as shown in FIG. 3B, the resistance required for the climbing portion from the first floor to the third floor is smaller than the propulsion force of the compressed air, so that the optical fiber cable can be reliably pumped to the third floor. it can. On the third floor, the light passes through the vicinity of the optical information processing device B and is pumped to the fourth floor through the duct 1. On the fourth floor, the optical fiber cable passes through the vicinity of the optical information processing device C, and the optical fiber cable is pumped through the duct 2 to the sixth floor. The resistance in this case is equal to the resistance when pumping from the first floor to the third floor, but the difference between the propulsion and the resistance is large because the propulsion is increasing, so that the optical fiber cable can be operated at higher speed. Is pumped. After passing through the vicinity of the optical information processing device D on the sixth floor, the optical fiber cable is pressure-fed to the first floor through the duct 1 and sent to the installation start point E. As described above, after the optical fiber cable has been pressure-fed into the tube installed along the path indicated by the broken line in FIG. 9A, the optical fiber cable in the tube is located at each position of the optical information processing devices A to D. The necessary optical fiber is taken out from the optical information processing device and connected to each optical information processing device, thereby completing the wiring.

In this embodiment, as compared with the embodiment shown in FIG. 1, a climbing portion having a large resistance is provided at a position relatively far from the tube entrance, so that the difference between the resistance and the propulsion can be increased. The optical fiber cable can be pumped from the first floor to the third floor at a higher speed.

In the optical wiring network configuration method shown in FIG. 3 (Application Example 1), one continuous tube is erected along the path shown by the broken line in FIG. The case where the optical fiber cable is pumped to the floor is shown. In this case, if a pumping device that supplies compressed air with a gauge pressure of 8 kg / cm ² at the inlet of the tube is used, the resistance becomes larger than the propulsion line (shown by a solid line in FIG. Cannot pump to the 6th floor. However, if a pumping device that can supply compressed air with a gauge pressure of, for example, 12 kg / cm ² is used, the propulsion line (indicated by the broken line in (b) in the same figure) exceeds the resistance, and the optical fiber cable can be pumped. become. In this case, an optical fiber cable first passes near the optical information processing device D during installation, as indicated by a broken line in FIG.

In the optical wiring network configuration method shown in FIG. 4 (application example 2), one continuous tube is erected along the path shown by the broken line in FIG. The optical fiber cable is pressure-fed, and first, the optical fiber cable passes near the optical information processing device C. In this case, if a pumping device that supplies compressed air with a gauge pressure of 8 kg / cm ² at the inlet of the tube is used, the resistance becomes larger than the propulsion line (shown by a solid line in FIG. Cannot be pumped to the 4th floor. However, if a pumping device that can supply compressed air with a gauge pressure of, for example, 12 kg / cm ² is used, the propulsion line (indicated by the broken line in (b) in the same figure) exceeds the resistance, and the optical fiber cable can be pumped. become. In this case, since the difference between the propulsion line and the resistance is larger than in the above-described application, the optical fiber cable is pumped at a high speed.

As described above, by setting the wiring network of the tube such that the resistance at each point is smaller than the propulsion line determined by the pressure of the compressed air supplied from the pumping device, or by propulsion that is larger than the resistance at each point. By applying a pumping device having a predetermined gauge pressure capable of setting a force line, the optical fiber cable can be reliably pumped.

The present invention is not limited to the above embodiment. For example, the laying start point, the laying route, the number of floors of the building, the number of optical information processing devices, and the like are arbitrary, and are not limited to the above-described embodiments and application examples. For example, there may be a plurality of optical information processing apparatuses on the same floor, and the optical fiber cable does not have to be finally sent to the installation start point.

The compressed gas is not limited to air, but may be, for example, an inert gas.

Furthermore, although the tube and the optical fiber cable are circular in the above embodiment, they are not limited to circular. The important thing is that the resistance level does not exceed the propulsion by compressed air,
It is to set the route of the optical fiber cable.

〔The invention's effect〕

Since the present invention is configured as described above, the optical fiber cable can be reliably pumped,
Workability when configuring the optical distribution network can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a method of configuring an optical distribution network according to one embodiment of the present invention, FIG. 2 is an explanatory diagram showing a method of configuring an optical distribution network according to another embodiment of the present invention, and FIG. Is the first application example of the present invention.
FIG. 4 is an explanatory diagram showing a method of configuring an optical wiring network according to the present invention, FIG. 4 is an explanatory diagram showing a method of configuring an optical wiring network according to an application example 2 of the present invention,
FIG. 5 is a schematic view showing an arrangement example of the optical information processing apparatus, FIG. 6 is a longitudinal sectional view showing an example of the structure of a pumping apparatus which can be used in the above-mentioned embodiment and application examples, and FIG. 7 is a pumping apparatus shown in FIG. FIG. 8 is a graph showing a propulsive force per unit length when compressed air is supplied by the device, and FIG. 8 is a view showing a principle of obtaining a frictional force fμ. 1, 2 duct, 3 pumping device, 4 optical fiber cable, 5 reel for supply, 6 tube
7 ... Compressed air inlet, A, B, C, D ... Optical information processing device, E ... Installation start point.

Claims (1)

(57) [Claims] 1. A method for constructing an optical distribution network in which an optical fiber cable is pressure-fed into a tube with a compressed gas using a pressure-feeding device, and the optical fiber cable is connected to an optical information processing device arranged over a multi-layer floor. In advance, based on the propulsion force in a state in which insertion becomes impossible by gradually reducing the propulsion force at the time of pumping the optical fiber cable to the climbing portion of the tube, the The resistance is determined as a function of the length of the optical fiber cable, and at each point on the tube that is laid so that the optical information processing device is placed on a series of wiring paths, the optical fiber cable is compressed by the compressed gas. So that the propulsion force per unit length given to the at least larger than the resistance force per unit length at the time of inserting the optical fiber cable into the tube, Configuration method of the optical wiring network and sets the gauge pressure of the wiring path or the pumping device of the fiber cable.