JP3116653B2 - Optical fiber airtight penetration module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for airtightly penetrating an optical fiber through an airtight shielding wall for preventing harmful substances or atmosphere from leaking, and more particularly to a technique for externally mounting a module body in an apparatus for airtightly penetrating the shielding wall. The present invention relates to a technique in which an optical fiber is hermetically penetrated as a sheath under a coating with a protective tube.

[0002]

2. Description of the Related Art In an airtight container for storing harmful substances such as radiation, a container is used for supplying power to a manipulator for performing various operations in the container and for monitoring the internal state. It is common practice to drill a through hole in a wall and to allow the through device to pass through the through hole in an airtight manner. Such a penetrating device generally has a sleeve that hermetically penetrates a through hole in a container wall, through which an electric wire or cable as an electric conductor or an optical fiber as an optical conductor is passed. The end of the sleeve is closed with a header plate,
In this part, the cylindrical end member of the module structure is hermetically pierced, and the conductor provided with the connector is pierced there,
Further, a seal structure is formed by filling with a resin.

There have been many proposals and practical applications of an electric conductor penetrating device. However, in the case of an optical fiber penetrating device, there are not many proposals, but almost no examples have been actively put into practical use. However, it could not be said that the technology for airtight penetration of optical fibers had been established. In particular, a reliable airtight penetration module having a connector at the end has not been found yet.

For example, FIG. 5 shows an example of a conventionally proposed optical fiber hermetic penetration module, in which a metal protection tube 7 for mechanical protection is penetrated into a metal module body 1 so that the module body can be opened. 1 is filled with a resin (epoxy resin) 2 to hermetically seal the gap between the protective tube 7 and the module body 1, and the optical fiber 4 is inserted and accommodated in the protective tube 7. The connector 6 is attached at the portion, but the end 5 of the optical fiber introduced into the connector 6 is exposed, and the portion is filled with the resin 2 to form an airtight portion of the protective tube itself.

Reference numeral 3 denotes a leak monitor space formed in the center of the module body by separating the resin sealing material 2. The pressure in this space is monitored from the outside through a small hole in the module body 1, so that it is airtight. It is designed to detect the presence or absence of a part leak. In the conventional optical fiber hermetic penetration module as described above, the hermetic sealing portion of the protective tube itself is provided at the connector mounting portion which also serves as an optical fiber exposed portion at the end of the protective tube 7, that is, at the end protruding from the end of the module body 1. Is formed,
Since the portion is exposed outside the module body and is not fixed, the hermetic seal portion may be damaged by mechanical external force due to careless handling. Further, since a rigid tube such as a stainless steel tube is used for the protective tube from the viewpoint of corrosion resistance and the like, the tube may be broken when a mechanical external force is applied in the same manner as described above, and handling is generally troublesome. Further, since the airtight sealing function is provided at the mounting portion of the connector 6, a special structure is required for the connector itself, which has caused a cost increase.

In view of the above-mentioned state of the art, the present invention has a high airtight sealing performance inside and outside a protective tube as a structure in which an optical fiber is housed in a protective tube for mechanical protection and passed through a module body. An object of the present invention is to provide an optical fiber hermetically sealed module of this type which is realized with reliability and is easy to handle.

[0007]

According to the present invention, there is provided an optical fiber airtight penetration module provided with a protective tube in which an optical fiber is inserted and accommodated therein, and the module body is filled with resin and hermetically sealed. An optical fiber hermetic penetration module having a structure in which a connector is attached at an end of a protective tube, in which the protective tube itself has an internal hermetic seal weir by injecting a resin into the protective tube through a cutout portion of the optical fiber. ,
The end of the protective tube extending from the end of the module body has been relieved of the need for airtightness, and the connector does not require a special structure.

High hermeticity can be assured by providing the internal hermetic seal weir of the metal tube itself in multiple stages at regular intervals in the longitudinal direction of the protective tube portion hermetically sealed in the module body. Also, the internal hermetic seal weir is preferably formed between spacers provided before and after the notch in the protective tube.

In addition, since the protection tube portion extending from the end of the module body is free from the hermetic seal as described above, the protection tube portion extending to the outside is bent by using a flexible tube. Can be liberalized. further,
Since the connector does not need to be specially structured as described above, an ordinary general-purpose optical connector can be used.

[0010]

FIG. 1 shows an embodiment of an optical fiber airtight penetration module according to the present invention. This embodiment is applicable to a reactor containment vessel penetration module. FIG. 2 is an enlarged view of a main part of the above example. FIG. 3 shows the internal structure of a protective tube for accommodating an optical fiber, and FIG. 4 shows a structure for connecting different types of protective tubes.

The module body denoted by reference numeral 1 is an end cylindrical body made of stainless steel or the like, and has a flange on an outer periphery thereof, which penetrates a header plate of a container wall penetrating device and is airtightly engaged via a packing. It is a thing.

The protection tube 7 is passed through the module body 1 as a rigid metal tube made of a stainless steel tube or the like. Then, a thermosetting resin such as an epoxy resin is injected into an internal gap surrounded by the outer surface of the protection tube 7 and the inner surface of the module body 1, filled and overheat-cured, thereby forming the outer hermetic seal 2 of the protection tube. ing.

As shown in FIG. 3, the protective tube 7 is provided with a small hole 8 'for releasing pressure in the middle in the axial direction, and a plurality of (two in the drawing) cutout portions 8 are provided before and after the small hole 8'. They are formed at regular intervals. In the protective tube 7, tube-shaped spacers 11, 11 are mounted in front and rear positions corresponding to the cutout portions 8, respectively, and the optical fiber 4 is passed through. Therefore, the optical fiber 4 is passed through the hollow portion of the spacer 11 at the center of the protective tube 7 or in a state close to the center. Then, a thermosetting resin such as an epoxy resin is passed through the cutout portion 8 to form a protective tube 7.
By injecting into the inside, the spacers 11
The inner space between them is formed with an internal hermetic seal weir 12 of the protective tube itself filled with the optical fiber 4 as the center. In the present embodiment, two internal hermetic seal weirs 12 are respectively formed before and after the middle in the axial direction corresponding to the number of the cutout portions 8. Internal airtight seal weir 12
Is formed to the position where the notched portion 8 of the protective tube 7 is left. The optical fiber 4 is coated with a resin having good adhesion to the resin forming the internal hermetic seal weir 12, for example, polyimide.

The protective tube 7 is set in the module body 1 after receiving the optical fiber and forming the internal hermetic seal weir 12 as described above, and forms the external hermetic seal 2. Therefore, as shown in FIG. 2, a part of the resin of the outer hermetic seal 2 enters the notched portion 8 of the protective tube left as described above, and the resin is formed on the surface of the inner hermetic seal weir 12. The airtight seal of the cutout portion 8 is formed by being integrated into an adhesive state.

The axially small hole 8 ′ of the protection tube 7 communicates with the leak monitor space 3 formed at the middle of the module body 1. If the leakage occurs, the pressure that increases due to the leakage increases
To increase the pressure in the leak monitor space 3, thereby operating the pressure monitoring device (not shown) connected through the small hole of the module body 1.

A flexible tube 9 is connected to both ends of the protection tube 7. The flexible tube 9 is made of a corrugated stainless steel tube, a plastic tube, or the like so as to flexibly adapt to bending. One end of the flexible tube 9 is a protective tube 7 which is a rigid tube as shown in FIG. Are externally fitted and connected. A tube-shaped spacer 11 'in the form of a funnel at the end is fitted to the end of the protective tube 7, and by passing the optical fiber 4 through the funnel-shaped portion on the extension side,
Care is taken to prevent the optical fiber 4 from touching the cut end surface of the protective tube 7 and damaging it. Further, a protection process is performed by the tube 10 over the end portion of the flexible tube 9 and the protection tube 7. As the tube 10, for example, a heat-shrinkable tube is appropriate. The flexible tube 9 connected to the protective tube 7 in this manner is such that the connection portion with the protective tube 7 is embedded in the external hermetic seal 2 as shown in FIG. The protrusion extends from the end of the module body 1 at an arbitrary length.

As shown in FIG. 1, the connector 6 for the optical fiber is connected and fixed by an appropriate method to the extended end of the flexible tube 9 after the terminal of the optical fiber 4 is connected.
The connection is made, for example, by making the casing of the connector 6 the same as the material of the flexible tube 9 and brazing (in the case of metal) or welding (in the case of plastic) the connector casing and the end of the flexible tube 9. And do.

In the above-described embodiment, there are four internal airtight seal dams 12 in the protective tube 7 itself. However, if at least one is located before and after the small hole 8 'for pressure leak in the middle in the axial direction, a predetermined value is required. Airtight seal is possible. In addition, each airtight seal weir 1
2 can increase the thickness of the weir by increasing the arrangement interval of the spacers 11 for further improving the reliability, and can also increase the creepage distance of the hermetic seal by filling the cutout portion 8.

In the above-described embodiment, the case where only one optical fiber 4 is inserted is shown. However, without changing the sealing performance, a plurality of optical fibers can be accommodated without any problem. In this case, the number of optical fibers to be stored can be increased. Further, the connector 6 can be of a multi-core type.

[0020]

According to the optical fiber hermetic penetration module of the present invention as described above, since the resin is injected into the protective tube from its own cutout portion, the internal hermetic seal dam of the protective tube itself is formed. The internal hermetic seal weir can be provided at any position in the axial direction of the protective tube,
Therefore, both the outer seal and the inner seal of the protection tube can be held in the module body, and therefore, there is no possibility that the hermetic seal is damaged by an external force, and the mechanical protection of the optical fiber is prevented. Airtight sealing performance can be realized with high reliability inside and outside the protective tube.

Further, since the protective tube portion extending from the module body has been released from the requirement of an airtight seal, the protective tube portion can be bent as desired in any direction as a flexible tube. By not receiving it, it is possible to protect it from breakage. Also, by being able to flexibly bend as described above, the direction of the terminal connector can be freely changed, and the terminal connector can be handled with a general-purpose product without a seal structure, and thus the connection with the external cable is easily performed. Become. Each of these advantages makes it easy to handle as a whole, and provides an optical fiber hermetic penetration module of this kind which is easy to use and more practical. In addition, it is possible to reduce the total cost by making the terminal connector a general-purpose product.

[Brief description of the drawings]

FIG. 1 is a front view showing a partially sectioned embodiment of an optical fiber hermetic penetration module of the present invention.

FIG. 2 is an enlarged longitudinal sectional view of a main part of FIG. 1;

FIG. 3 is a longitudinal sectional view showing the internal structure of the protection tube of FIG.

FIG. 4 is a longitudinal sectional view showing a connection state between the protection tube and the flexible tube in FIG. 1;

FIG. 5 is a partial front view showing an example of a conventional optical fiber hermetic penetration module.

[Description of Signs] 1 Module body 2 External airtight seal 3 Leak monitor space 4 Optical fiber 6 Connector 7 Protective tube 8 Notch 9 Flexible tube 11 Spacer 12 Internal airtight seal weir

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 6/00 H02G 3/22 H05K 7/00

Claims (4)

(57) [Claims] An optical fiber hermetic penetration module having a structure in which a protective tube in which an optical fiber is inserted and accommodated is passed through a module body, a resin is filled in the module body to hermetically seal, and a connector is attached at an end of the protective tube. An optical fiber hermetic penetration module characterized in that the protective tube itself has an internal hermetic seal weir by injecting a resin into the protective tube through a cutout portion of itself. 2. The optical fiber hermetically sealed module according to claim 1, wherein the internal hermetic sealing weirs of the protective tube itself are provided in multiple stages at regular intervals in a longitudinal direction of a portion of the protective tube hermetically sealed in the module body. 3. The optical fiber hermetic penetration module according to claim 1, wherein the inner hermetic seal weir is formed between spacers provided before and after the notch in the protective tube. 4. An optical fiber hermetically sealed module having a structure in which a protective tube in which an optical fiber is inserted and accommodated is passed through a module body, a resin is filled in the module body to hermetically seal, and connectors are attached at both ends of the protective tube. The protective tube itself has an internal hermetic seal weir by injecting resin through its own notch into the protective tube, and the protective tube portion extending from the end of the module body can be made of metal or plastic. An optical fiber hermetically sealed module comprising a flexible tube.