JP2667233B2 - Heat shrink tube heater for optical fiber reinforcement - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube heater used for connecting an optical fiber, and more particularly, to heating a heat shrinkable tube for reinforcing a connection portion of the optical fiber. The present invention relates to a heat-shrinkable tube heater for reinforcing an optical fiber for shrinking.

[Prior Art] Conventionally, as this type of tube heater, for example, a tube heater having a heater shown in FIG. 4 is known. In FIG. 4, reference numeral 1 denotes a heater. The heater 1 has a housing portion for housing a connecting portion 3 of a pair of optical fibers 2 and 2 and its vicinity, and a heat-shrinkable tube 4 for reinforcement. 5 are formed. The heater 1 also connects the portion of the tube 4 that covers the connection portion 3 where the coating layers 6 and 6 of the optical fibers 2 and 2 have been removed and the vicinity thereof to the coating layers 6 and 6.
In order to prevent the heat-shrinkable tube from shrinking from the center portion toward both ends in order to prevent air from remaining inside, the heat shrinkable tube shrinks more than the portion of the tube 4 that covers the heater 1. In the length direction), the heating temperature distribution as shown in FIG. Here, point A in FIG.
Corresponding to the position of the center of the storage section 5 in the figure (the center of the housed tube 4), point B in FIG. 5 corresponds to the tip 6a of the coating layer 6 of the optical fiber 2 in FIG. Corresponding to the position, the point C in FIG. 5 corresponds to the position of the end of the storage section 5 (end of the tube 4) in FIG. Further, the relationship between the heating time and the heating temperature at each point of the heater 1 corresponding to the points A, B and C becomes substantially constant after a certain time has elapsed from the start of the heating as shown in FIG.

Further, as the tube 4, a tube composed of a hot-melt type adhesive layer that directly covers the optical fiber 2 and an electron beam crosslinked polyethylene heat-shrinkable tube that is tightened from the outside of the adhesive layer is used.

Using such a tube heater, the optical fibers 2, 2
In order to connect and reinforce this, first, the tube 4 is extrapolated to one of the optical fibers 2, and then the optical fibers 2, 2
After removing the coating layers 6 and 6 at the respective tips, the tips (connection portions) are butted and joined by a well-known method.

Next, the tube 4 is moved so that the connecting portion 3 of the optical fibers 2 and 2 is located substantially at the center of the tube 4, and is housed in the housing 5 of the tube heater as shown in FIG. . After that, the power source (not shown) is turned on to turn on the heater 1, and the tube 4 is moved according to the temperature distribution shown in FIG.
Is heated to shrink the tube 4, and the optical fiber 2,
The connection portion 3 and the vicinity thereof are closely fixed and reinforced.

"Problems to be Solved by the Invention" However, the above-described tube heater has the following disadvantages.

In the above tube heater, heating of the tube is performed with a distribution as shown in FIG. 5, but as shown in FIG. 5, the temperature difference between points B and C is equal to or greater than the temperature difference between points A and B. Therefore, if the temperature at the point C is set to shrink both ends of the tube, the temperature at the point B becomes considerably higher than the temperature for shrinking the tube. In particular, when joining and reinforcing a material having a large cross-sectional area, such as a multi-core tape core wire, the heating temperature at point B is considerably higher than the temperature required for shrinking the tube. Bubbles are generated from the tip of the layer or the like and remain in the tube, which prevents sufficient reinforcement of the optical fiber joint.

In addition, if the heating temperature of the heater is set so that the heating temperature at point B is low in order to prevent the generation of air bubbles from the coating layer tip, etc., the temperature at point C becomes too low, and both ends of the tube become insufficient. It will not be heated and will not shrink.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reinforce an optical fiber capable of sufficiently shrinking both ends of a tube without generating bubbles from the coating layer of the optical fiber upon heating. It is to provide a heat shrink tube heater.

[Means for Solving the Problems] In the optical fiber reinforcing heat shrinkable tube heater of the present invention, the temperature of the heater is set to a temperature at which only the central portion of the reinforcing heat shrinkable tube is heated or shrunk or both ends of the tube are heated. The above problem was solved by providing a heating temperature switching mechanism for setting the temperature for contraction.

[Operation] According to the heat shrinkable tube heater for reinforcing an optical fiber of the present invention, the heating temperature switching mechanism is provided in the heater, so that the tube is heated at an appropriate temperature at which no bubbles are generated from the coating layer of the optical fiber, and the tube is once heated. By shrinking the central part and then increasing the heating temperature of the heater to heat it, and shrinking both ends of the unshrinked tube, the generation of air bubbles from the coating layer is prevented, and the tube is good over its entirety. To shrink.

Embodiment FIG. 1 shows an embodiment of a heat-shrinkable tube heater for reinforcing an optical fiber according to the present invention. In this figure, the same components as those shown in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. The difference between the tube heater shown in FIG. 1 and the tube heater shown in FIG. 4 is that a heater 1 is provided with a heating temperature switching mechanism.

A heating temperature switching mechanism 7 is connected to the heater 1 in the tube heater shown in FIG. The heating temperature switching mechanism 7 includes a heater control unit 8 connected to the heater 1 as shown in FIG.
A comparator 9 for inputting a heater ON / OFF control signal to the control unit; a control unit 10 for inputting a heater temperature set value to the comparator 9;
And a temperature sensor 11 which senses the temperature at the measured position and inputs it to the comparator 9. The heater control unit 8 turns on / off the heater 1 in response to the heater ON / OFF control signal from the comparator 9.
Enter the sensed temperature from 11 and compare it, then turn on heat ON / O
The FF control signal is also input to the heat controller unit 8. The control unit 10 includes a heater temperature setting unit 12 and a timer 13 for switching the signal from the heater temperature setting unit 12 according to time. The value is switched and input stepwise. The temperature sensor 11
The sensing portion 11a is disposed on the heater 1 at a position corresponding to the position of the tip 6a of the coating layer 6 of the optical fiber 2 as shown in FIG. It senses temperature.

In order to connect and reinforce the optical fibers 2 and 2 using the tube heater having such a configuration, first, the initial value of the heater heating temperature at the point B and the set value after the switching,
The heating time at each set temperature is input to the control unit 10. In this case, the setting of the heating temperature and the heating time is appropriately determined depending on the materials of the optical fibers 2 and 2 and the tube 4 to be reinforced, and the initial value of the heating temperature is the coating layer 6 of the optical fibers 2 and 2, No air bubbles are generated from the tips 6a, 6a, etc. of the tube 6, and the temperature at which the tube 4 shrinks sufficiently at the point B is set. The heating time at this initial value is also the time at which the point B shrinks sufficiently. It is said.

Next, as in the case of the conventional heater shown in FIG.
The tube 4 is extrapolated to the optical fiber 2, and the optical fibers 2, 2
After removing the coating layers 6, 6 at the respective tips, the tips (connection locations) are butted and connected by fusion. Next, the tube 4 is moved to a predetermined position, and in that state, is housed in the housing 5 of the tube heater as shown in FIG.

Thereafter, a power source (not shown) is turned on, and the heater 1 is turned on to heat the tube 4 at an initial set temperature (initial value). Then, since the heater 1 has a heating distribution as shown in FIG. 5, the tube 4 is sufficiently contracted between BB in FIG.
That is, since the heating temperature is lower than the temperature at the point B between B and C in FIG. 1, it does not shrink. Further, when a predetermined time elapses, the heating temperature of the heater 1 is automatically switched by the timer 13 and rises to the preset heating temperature after the switching. And, by this, the uncontracted portion of the tube 4 also
It contracts due to an increase in the heating temperature. In this case, since the portion between BB of the tube 4 is once heated at an appropriate temperature and is already contracted, air bubbles from the coating portions 6, 6 of the optical fibers 2, 2 remain even after the heating temperature is increased. Does not occur.

After a certain period of time has passed and the uncontracted portion of the tube 4 has been sufficiently contracted, the power supply to the heater 1 is stopped to end the heating, and the optical fibers 2 and 2 that have contracted and been reinforced by the tube 4 are removed. Remove from the tube heater.

In the tube heater having such a configuration, first, the tube is heated so as to have an appropriate temperature at point B in FIG. 1, and after the central portion of the tube 4, that is, the space between BB is once contracted, Since the unshrinked portion is further shrunk by heating at a high temperature, the tips 6a and 6a of the coating layers 6 and 6 of the optical fibers 2 and 2 are heated at an appropriate temperature to prevent the generation of bubbles. Further, even after the heating temperature rises, since the tube 4 has already been contracted in the vicinity of the tip portions 6a, 6a of the coating layers 6, 6, no bubbles are generated, and therefore the entire tube 4 contracts favorably. Optical fiber 2, 2
Is sufficiently reinforced.

In the above embodiment, the temperature is switched in two stages, but may be switched in three or more stages according to the length, material, and the like of the tube 4. Further, although the heating temperature is automatically switched, it may be manually switched.

(Experimental example) Using the tube heater shown in FIGS. 1 and 2,
The connected pair of single-core optical fibers was reinforced with a tube. In this case, the setting of the heater temperature in the control unit 10 shown in FIG. 2 is set to an initial value of 100 ° C., a temperature after switching to 130 ° C. as shown in FIG. 3, and a time from the start of heating to the temperature switching. For 2 minutes, and the time from the start of heating to the end of heating was 3 minutes and 30 seconds. The ambient temperature at this time was set to 0 ° C.

When the tube was shrunk by heating in this way, no bubbles were generated, and the entire tube shrank favorably, confirming that the optical fiber was sufficiently reinforced.

[Effects of the Invention] As described above, the heat shrinkable tube heater for reinforcing an optical fiber of the present invention has a heater provided with a heating temperature switching mechanism. Therefore, in use, the tube is heated at an appropriate temperature at which air bubbles are not generated from the coating layer of the optical fiber to temporarily shrink the central portion of the tube, and then the heating temperature of the heater is increased to heat the tube. Can be prevented from generating air bubbles from the coating layer, and can be satisfactorily shrunk throughout the tube. As a result, it is possible to reliably reinforce the connection portion of the optical fiber, and it is possible to sufficiently reinforce a fiber having a large cross-sectional area such as a multi-core tape.

[Brief description of the drawings]

FIGS. 1 to 3 relate to a heat-shrinkable tube heater for reinforcing an optical fiber according to the present invention. FIG. 1 is a schematic diagram showing an embodiment of a tube heater, and FIG. FIG. 3 is a schematic configuration diagram of a switching mechanism. FIG. 3 is a graph showing a relationship between a heating time and a heating temperature in a temperature sensor sensing unit.
FIGS. 6 to 6 are diagrams relating to a conventional tube heater, FIG. 4 is a schematic configuration diagram showing an example of a conventional tube heater, and FIG. 5 is a distribution of a heating temperature at each point of the tube heater. FIG. 6 is a graph showing the relationship between the heating time and the heating temperature at each point of the tube heater. DESCRIPTION OF SYMBOLS 1 ... Heater, 2 ... Optical fiber, 3 ... Connection part, 4 ... Heat-shrinkable tube for reinforcement, 5 ... Storage part, 6 ... Coating layer, 7 ... Heating temperature switching mechanism.

Claims (1)

(57) [Claims] An optical fiber reinforcing heat shrinkable tube heater used for connecting at least a pair of optical fibers, wherein the reinforcing heat shrinkable tube externally attached to a connection portion of the optical fiber is heated. A heater for shrinking and reinforcing the connection portion, providing a storage portion for storing the optical fiber connection portion and the heat shrinkable tube for reinforcement, and providing the heater with a temperature at the center of the storage portion; Is set to be high and the temperature at both ends can be heated low, and the temperature of the heater is set to a temperature at which only the central part of the heat shrinkable tube for reinforcement is shrunk or a temperature at which both ends of the tube are heat shrunk. A heat-shrinkable tube heater for reinforcing an optical fiber, which is provided with a heating temperature switching mechanism.