JPS5983118A - Joint chamber for optical submarine repeater - Google Patents

Abstract

PURPOSE:To improve reliability on airtightness by sealing the inside of a joint chamber by means of two rings; a watertight seal ring and an airtight seal ring. CONSTITUTION:A chamber body 19 is assembled to an end plate 17, and a suction pipe 28 is connected to an internal screw part 26 to evacuate said part. The suction pipe is connected to a leak detector. When a viscous liquid is injected into a seal part 2 after the presence or absence of leakage is decided, the liquid is sucked into the very small clearance in the part 22 to the part of an O-ring 23. The pipe 28 is then removed from the body 19 and the viscous liquid is filled in a hole 27 for an airtight test. A sealing plug 30 is screwed into the part 26. Optical fibers are connected and after a chamber cover 20 is assembled to the body 19, gaseous helium is supplied through a hole 31 for supplying a packing fluid into the joint chamber; at the same time, the pipe 28 is screwed into the part 26 for the hole 27 and the airtight test of an airtight seal ring 24 is performed. After the gaseous helium is injected for a specified time, the plug 30 is screwed into the part 26 of the hole 31.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a joint chamber in which a connecting portion between an optical submarine cable and an optical submarine repeater is housed in an airtight state, and particularly aims to improve airtight reliability and speed up airtight testing. It was planned.

In recent years, progress has been made in the practical application of optical transmission systems that use optical fiber as the entire transmission medium. A major feature is that the entire section can be extended over long distances. However, in order to fully realize a long-distance optical submarine transmission system such as across oceans, dozens to hundreds of optical submarine repeaters must be installed in each cable section.

Must not be. Therefore, it becomes essential to connect the optical submarine cable and the optical submarine repeater on board the cable-laying ship. On the other hand, optical fibers are mechanically brittle because their main component is quartz (silicon dioxide), and their mechanical strength deteriorates in environments with a large amount of moisture. Therefore, when converting optical fiber into a submarine cable, it is necessary to protect the optical cable from water pressure and prevent moisture from entering, but this also applies to the connection parts of optical submarine repeaters and the like. Applicable.

From this point of view, a connection device for optical submarine cables as shown in Figure 1 has been developed, but this is a repeater (not shown)? The optical fiber 15 from the optical repeater and the optical cable 1 are connected to the stored repeater housing 11 and the retainer 13 that fully protects the end of the optical cable 12 through the pupil protection sleeve 14'.
The optical fiber 16 of No. 2 is connected to the inside of the joint chamber 18, which is opened to the end plate 17 of the repeater housing 11. Therefore, the optical fiber 15.
6 is exposed in the joint chamber 1B formed by the channel body 19 and the chamber cover 20, so in order to ensure the reliability of this optical fiber connection, it is necessary to especially inspect the inside of the joint chamber 18. Must be kept dry and airtight. Also, considering that the work will be carried out on a ship, it is desirable to simplify these structures as much as possible.

By the way, in order to achieve an airtight structure for the joint chamber 18, it is possible to weld the chamber body 19, the end plate 17, and the chamber cover 20, or to interpose a seal ring between each of them. . However, welding cannot be used because it is difficult to work on a ship, and it is necessary to maintain complete airtightness with a seal ring. In this case, airtightness is largely determined by the presence or absence of scratches on the groove or seal ring, and the quality of the plating when a metal seal ring is used, so it is necessary to perform an airtightness test after assembly is completed. Therefore, when the inside of the joint chamber 18 is evacuated by a vacuum tube and connected to a leak detector to check its airtightness, the inside of the joint chamber 18 is communicated with the inside of the optical cable 12 via the feedthrough 21. Therefore, the inside of the optical cable 12 must be evacuated, and the time required for evacuating becomes extremely long. Generally, when connecting an optical submarine cable, it is necessary to keep the cable-laying ship at a fixed position at sea for a long time, but if all weather and sea conditions are taken into consideration, the time required for onboard work must be shortened as much as possible. Therefore, in order to shorten the evacuation work time, it is better to use a vacuum pump with a large evacuation capacity, but this results in an increase in the size of the device, poor workability, and high cost.

It is an object of the present invention to provide a joint chamber that can complete the airtightness test without any problems occurring during the conventional airtightness test and has excellent airtightness reliability.

The structure of the joint chamber for an optical submarine repeater of the present invention that achieves all of these objects is such that one end is fitted into the end plate of the repeater housing, and the optical fiber (connection part) of the optical submarine cable connected to the repeater is fitted into the end plate of the repeater housing. A cylindrical chamber body in which is stored, a chamber cover that is fitted to the other end of the main body and seals the inside of the main body; (Installed at the sealing parts of the main body, the end plate, and the chamber cover, respectively)
a watertight seal ring attached to the chamber, an airtight ring attached to the seal portion on the inside of the chamber further than these watertight seal rings; an airtightness test hole which is provided and has one end opening in the seal portion between the watertight seal ring and the airtight seal ring, and the other end of which is connected to a vacuum pump for airtightness testing; and a sealing plug that is tightly attached to the airtight test hole after the airtight test drive is completed to seal the viscous liquid injected inside.

Hereinafter, an embodiment in which the joint chamber for an optical submarine repeater according to the present invention is incorporated into the conventional device shown in FIG. 1 will be described in detail with reference to FIGS. 2 to 4. Since this is only the sealing portion between the support chamber body, the support plate, and the chamber cover, only this portion will be explained, and the other portions will be denoted by the reference numerals in FIG. 1. As shown in FIG. 2, which is an enlarged view of the sealing portion between the chamber body 19 and the chamber cover 20, and FIG. 3, which is an enlarged view of the sealing portion between the end plate 17 of the repeater housing 11 and the chamber main body 19, Chamber body 19 and end plate 17 that fit together
O-rings (water-tight seal rings) 23 made of rubber or the like are attached to the sealing portions 22 with the chamber cover 20 and the sealing portions 22, respectively. However, these O-rings 23 can prevent the fluid from flowing out of the joint chamber 18. In addition, each seal part 22 inside the joint chamber 18 from the 01J ring 23 has a Q made of metal or the like.
An airtight seal 1 non-gang 24 such as an IJ ring or a CIJ ring is installed to seal outside air entering the joint chamber 18 through the O-ring 23. Furthermore, the end plate 17 is attached by bolts (not shown) or the like.
The chamber body 19 is integrally attached to the chamber body 19, and the chamber body 19 is integrally attached to the chamber body 19 by bolts (not shown). An airtight test hole 27 is drilled in the female threaded part 26, which opens into the sealing part 22 between the ring 24 and connects to the female threaded part 26, which has a cape seal part 25 at the other end. 4(a), which is connected to a vacuum pump (not shown) and a detachable ring 29 of the suction tube 28 shown in FIG. A sealing plug 30 as shown in (b) is screwed in. Note that the female threaded portion 26 may be placed on the outer periphery of the chamber body 19 and the cover 20. In the embodiment, a filling fluid supply hole 31 is provided in the chamber cover 32 for supplying a dry gas such as helium or the above-mentioned viscous liquid into the joint chamber 18 in order to create a non-oxidizing atmosphere inside the joint chamber 18. This filling fluid supply hole 31 is also provided with an internal threaded portion 26 having a cone seal portion 25 for attaching the sealing plug 30. Thus, in this embodiment, the airtight seal is Even when used for 24 hours, oxidation corrosion can be prevented and a stable airtight effect can be maintained for a long period of time.

Assemble the chamber body 19 to the end plate 17, connect the suction pipe 28 to the female threaded portion 26 of the chamber body 19, evacuate it with a vacuum pump, and connect it to a leak detector (not shown). In this case, since the only part that is pulled out is the seal part 22, the presence or absence of a leak can be determined in a very short time.If the entire viscous liquid is injected into the seal part 22 from the outside in this state, the external pressure will be reduced. The viscous liquid is automatically sucked into the minute gap of the seal portion 22 up to the OIJ ring 23 without adding it. This phenomenon also occurs in the seal portion 22 between the chamber body 19 and the chamber cover 20. Next, remove the entire suction tube 28 from the chamber body 19, inject all of the viscous liquid into the airtight test hole 27, and screw it into the female threaded part 26 of the chamber body 19 into the sealing plug 30'. This work can be carried out primarily on the ground. Next, optical fiber 15.16 was installed on board the cable laying ship.
After connecting the chamber cover 20 to the chamber body 19, helium gas is supplied into the gold joint chamber 18 from the filling fluid supply hole 31, and the suction pipe 28
into the female threaded portion 26 of the airtight test hole 27, and perform a complete airtight test on the airtight seal ring 24 in the same manner as described above. Note that it is also possible to separately perform the sealing operation after injecting helium gas for a certain period of time.

As described above, according to the joint chamber for an optical submarine repeater of the present invention, since the inside of the joint chamber is sealed with two seal rings, a watertight seal ring and an airtight seal ring, the airtight reliability is extremely high. There is one person who is very talented. Also, 7
Since the seal between the wide seal ring and the airtight seal ring is vacuumed and the airtightness test is performed, airtightness can be confirmed in an extremely short time, which is intended to shorten the time required for onboard work. It is possible.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a schematic structure of a connection part between a conventional optical submarine repeater and an optical submarine cable, and FIGS. 2 and 3 show an embodiment of a joint chamber for an optical submarine repeater according to the present invention, respectively. Sectional view showing enlarged structure 7 of the seal part, No. 4
Figure (a) is a cross-sectional view of the suction tube attached to the female thread part.
FIG. 4(b) is a front view of a sealing plug that is screwed into the female threaded portion similarly to FIG. 4(a). Further, in the reference numerals in the figure, 12 is an optical cable, 15 and 16 are optical fibers, 17 is an end plate, 18 is a joint chamber, 19 is a Vi chamber body, 20 is a chamber cover, 22 is a sealing part, 23 is an O ring, and 24 is a Gasket, 27 is a hole for airtightness test, and 30 is an N stopcock. Patent Applicant International Telegraph and Telephone Corporation Representative Patent Attorney Shibu Mitsuishi (and 1 other person)

Claims (1)

[Claims] One end fits into the end plate of the repeater housing, and the other end fits into a cylindrical chamber body in which the optical fiber connection part of the optical submarine cable connected to the repeater is housed. and a chamber cover that completely seals the inside of the chamber body, and a seal portion between the chamber body, the end plate, and the chamber cover. Water-tight seal rings are attached to each of the chamber bodies, air-tight seal rings are attached to the seal portions inside the chamber body, and these water-tight seal rings are attached to the chamber body and the chamber cover. an airtightness test hole which is provided at each of the holes and has one end opened in the seal portion between the watertight seal ring and the airtight seal ring, and the other end of which is connected to a vacuum pump for airtightness testing; A joint chamber for an optical submarine repeater consisting of a sealing plug that is tightly fitted into the airtightness test hole and seals the viscous liquid injected inside after the airtightness test is completed.