JPH0328402Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an optical fiber introduction part of a pressure-resistant container that has improved watertight sealing effects and protection effects for optical fibers and storage equipment.

[Conventional technology]

In the field of ocean development, which has been actively promoted in recent years, the use of optical fibers as signal transmission lines connecting underwater equipment and onboard ships is being considered. in this case,
An optical fiber introduction section will be provided in the pressure container that houses the photoelectric converter. As shown in FIG. 4, for example, what has been conventionally considered as this optical fiber introduction part is a cylindrical penetration fitting 3 with a flange fixed to the wall of a pressure-resistant container 1 via an O-ring 2. The structure is such that an optical fiber 5 is passed through the hole through a water pressure sealing material 4, and the introduced optical fiber 5 is connected to a photoelectric converter 7 using an optical connector 6 inside the container 1.

[The problem that the idea aims to solve]

Since the above-mentioned optical fiber introduction part has only one sealing part between the inside and outside of the pressure-resistant container 1, the reliability of the watertight seal is low, and there is a concern that water may infiltrate into the inside of the container.

Furthermore, since it is necessary to remove the penetration fitting 3 to connect the optical fiber to the photoelectric converter, moisture-containing outside air flows into the container, and the inflowing water and outside air may adversely affect the internal equipment. is possible.

In addition, while the pressure inside the container 1 is always atmospheric pressure, the external water pressure increases with water depth. Therefore, the pressure difference between the inside and outside of the container is directly applied to the water pressure sealing material and the optical fiber inside the penetrating fitting 3. In addition, as shown in FIG. 5, if the differential pressure exceeds 400 kg/cm ² , the distortion of the sealing material increases, causing microbends in the optical fiber, and there is a problem in that the optical transmission loss at the penetration portion increases significantly.

[Means to solve the problem]

In order to eliminate the above-mentioned problems, this invention was developed by inserting an internal optical fiber through a water pressure sealing material into a penetration fitting in the wall of the container that has a seal between it and the pressure container. A pressure-resistant case that surrounds the metal fittings and forms a liquid-tight connection chamber between the metal fittings is sealed and fixed to the container, and the metal fittings that penetrate the case are sealed with water-resistant pressure cases. Insert the external optical fiber through the sealing material,
Connecting one ends of the internal and external optical fibers in the connection chamber, and sealing a fluid in the connection chamber,
Furthermore, the above-mentioned pressure-resistant case has a movable body to which the force of a differential pressure adjustment spring is applied to one end, or a movable body whose pressure-receiving area at one end is larger than the pressure-receiving area at the other end, and the space between the pressure-resistant case and the pressure-resistant container is sealed. Either install a pressure regulator that applies the fluid pressure in the connection chamber to one end of the movable body and the external water pressure to the other end to maintain the fluid pressure at a value below the external water pressure and above atmospheric pressure, or by increasing the fluid pressure. It has flexibility that can be increased to a value lower than external water pressure and higher than atmospheric pressure.

[Effect]

According to the configuration of the present invention described above, the water pressure sealing portion between the inside and outside of the container is doubled. In addition, by adjusting the fluid pressure in the connection chamber, the effect of dividing the pressure applied to the seal part (this effect will be explained in detail later) can be obtained, and the pressure burden on the seal part is also reduced, resulting in a water-prevention effect. It increases. Furthermore, since the optical fiber connection chamber is located outside the pressure-resistant container, there is no need to remove the penetration fitting when connecting the optical fiber, so moisture and the like can be prevented from flowing into the container.

Furthermore, the pressure applied to the optical fiber is reduced due to the above-mentioned pressure division effect, so that optical transmission loss is also reduced.

〔Example〕

Embodiments of this invention are shown in the attached FIGS. 1 to 3.

As shown in FIGS. 1 and 2, a cylindrical through fitting 3 with a flange is provided on the wall of the pressure vessel 1 as in the conventional case.
The internal optical fiber 5a is attached via the ring 2 and is inserted through the hole filled with the water pressure sealing material 4 of this metal fitting.
is being brought out. One end of the internal optical fiber 5a is connected to a photoelectric converter 7 via an optical connector 6, and another optical connector 8a is attached to the other end.

On the other hand, a pressure-resistant case 10 whose joint surface is sealed with an O-ring 9 is fixed to the outer surface of the pressure-resistant container 1 via bolts 11 . This pressure case 10 is
A recess 1 that surrounds the exposed portion of the penetrating fitting 3 and forms an optical fiber connection chamber 12 between it and the end face of the fitting.
3, and a penetrating fitting 3' having the same shape as the penetrating fitting 3 is inserted and fixed concentrically with the fitting 3 via an O-ring 2' in the pressure wall at the end of the recess 13. An external optical fiber 5b is passed through the hole via a water pressure sealing material 4'. An optical connector 8b is attached to the end of the external optical fiber 5b drawn into the connection chamber 12 to be coupled to the optical connector 8a.

Also, in the connection chamber 12, optical connectors 8a, 8
After connection b, a fluid 14 such as matching oil is injected from an inlet 15 provided in the pressure-resistant case and sealed with a stopper 16. Note that the optical fibers within the connection chamber can be connected by fusion splicing in addition to connection by connectors.

Next, the pressure-resistant case 10 includes a pressure regulator 17 that maintains the fluid pressure in the connection chamber 12 at a value lower than the external water pressure and higher than the atmospheric pressure, preferably at an intermediate value between the external water pressure and the atmospheric pressure. installed. This device 17 has a balance piston 20 whose outer periphery is sealed with an O-ring 19 and a differential pressure adjustment spring 21 that biases the piston in one direction inserted into a small hole 18 penetrated by a pressure-resistant wall of a case 10. Furthermore, a piston retaining cap 22 is screwed onto the tip of the protrusion of the pressure wall, and the piston 20 receives the pressure of the fluid 14 and the spring 21 on one end surface, and the cap 2 on the other end surface.
In response to the external water pressure introduced from the external pressure introduction hole 23 of No. 2, it moves until the opposing forces are balanced as shown in FIG. 3, and then stops. Therefore, the pressure of the fluid 14 can be maintained at the target value by adjusting the spring strength of the spring 21, which functions to cancel the thrust of the piston due to the differential pressure between the external water pressure and the fluid pressure. The effect of dividing the differential pressure can be obtained. For example, this pressure regulator can control the external water pressure.
When the pressure of the fluid 14 is maintained at 300Kg/cm ² at the time of 600Kg/cm ² , a pressure difference of 300Kg/cm 2 between the atmospheric pressure and the fluid pressure acts on the sealing part of the penetrating fitting 3, and the pressure difference of 300Kg/cm ² acts on the sealing part of the fitting 3'. The differential pressure between the external water pressure and the atmospheric pressure is applied to the two seals in two parts, such that a differential pressure of 300 kg/cm ² acts between the external water pressure and the fluid pressure, and this split effect causes the water pressure sealing material and the light The distortion of the fiber is suppressed to a small level, making it difficult for water to enter through the penetration portion, and optical transmission loss is also reduced.

It is most desirable to set the strength of the spring 21 so that the pressure of the fluid 14 is 1/2 of the external water pressure, but as shown in Figure 5, the transmission loss due to the pressure of the optical fiber is up to 400 kg/ ^cm2 . is maintained at approximately OdB, so it is sufficient to set it within a range where no more pressure is applied to either seal portion. Further, if one end of this spring 21 is screwed into a pressure-resistant case and supported by an adjustment screw or the like to make the spring strength variable, it is possible to cope with changes in water depth.

Incidentally, if the balance piston 20' shown in FIG. 6 is used to adjust the pressure of the fluid 14, the spring becomes unnecessary.
This piston 20' has a pressure receiving area B for fluid pressure larger than a pressure receiving area A for external water pressure. For example, if the ratio of A:B is set to 1:2, the pressure of the fluid 14 will change depending on the change in external water pressure. 1/2 of that water pressure regardless
is adjusted to

Furthermore, when there is no need to greatly increase the fluid pressure, the pressure-resistant case may be made flexible in place of the pressure regulator, and the effect of dividing the differential pressure may be obtained by reducing the volume of the connection chamber 12 due to external pressure. However, at this time, care must be taken to prevent the pressure case from buckling.

In addition to the above, the procedure for attaching the pressure-resistant case 10 to the container 1 and the procedure for attaching the penetrating fitting 3' to the case 10 may be carried out first.

Further, the optical fibers 5a and 5b may be either single-core or multi-core.

Furthermore, if silicone oil or the like with an optical refractive index close to that of glass is used as the fluid 14, when optical fiber connections are made within the connection chamber via optical connectors,
Even if the oil flows between the coupling connectors, there is no need to worry about increasing optical transmission loss.

〔effect〕

As explained above, the optical fiber introduction part of this invention has a double water pressure sealing part and also maintains the fluid pressure in the connection chamber at a value lower than the external water pressure and higher than the atmospheric pressure. The pressure difference between the pressure and the atmospheric pressure is divided into two seal parts, and the distortion caused by the pressure of the water pressure sealing material in each seal part is suppressed to a small level, so the reliability of the watertight seal is high and the pressure inside the container is kept low. There is almost no risk of water ingress.

In addition, since the optical fiber connection chamber is located outside the pressure-resistant container, there is no need to remove the penetration fitting when connecting or disconnecting the optical fiber, which prevents moisture from flowing into the container and protects the internal equipment. increases sufficiently.

Furthermore, due to the effect of dividing the pressure difference, the strain caused by the pressure on the optical fiber can be suppressed to a small level, so that the optical transmission loss in the penetrating portion is also reduced. Depending on the pressure of the fluid in the pressure case, it is possible to keep the transmission loss to zero.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of an example of the optical fiber introducing section according to this invention before the pressure-resistant case is connected, Fig. 2 is a cross-sectional view after the pressure-resistant case is connected, and Fig. 3 shows the operating state of the pressure regulating device. 4 is a sectional view of a conventional optical fiber introducing section, FIG. 5 is a bluff showing transmission loss due to water pressure in the optical fiber penetration section, and FIG. 6 is a sectional view showing another embodiment of the pressure regulating device. It is. 1...Pressure container, 3, 3'...Penetration fitting, 4,
4'... Water pressure sealing material, 5a... Internal optical fiber, 5b... External optical fiber, 8a, 8b... Optical connector, 10... Pressure resistant case, 12... Connection chamber, 13... Recess, 14 ...Fluid, 17...Pressure regulator, 20, 20'...Balance piston,
21...Spring.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) An internal optical fiber is inserted through a water pressure sealing material into a penetration fitting in the container wall that has a sealing part between it and the pressure-resistant container, and a penetration fitting is provided on the outer surface of the container. A pressure-resistant case that surrounds the container and forms a liquid-tight connection chamber between it and the metal fitting is sealed and fixed to the container, and a water-resistant seal is attached to the metal fitting that seals between this case and penetrates the case. An external optical fiber is inserted through the material, one end of the internal and external optical fibers are connected in the connection chamber, and a fluid is sealed in the connection chamber. or a movable body whose pressure-receiving area at one end is larger than the pressure-receiving area at the other end. Either install a pressure regulator that maintains the fluid pressure at a value below external water pressure and above atmospheric pressure by applying external water pressure to each, or increase the fluid pressure to a value lower than external water pressure and higher than atmospheric pressure. Optical fiber introduction part of pressure container with flexibility. (2) The optical fiber introduction part of the pressure-resistant container according to claim (1), wherein the internal and external optical fibers in the connection chamber are connected via an optical connector. (3) The optical fiber introduction part of the pressure-resistant container according to claim (1) of the utility model registration, characterized in that the internal and external optical fibers in the connection chamber are fusion-spliced. (4) The pressure-resistant container according to any one of claims (1) to (3) of the claims for utility model registration, characterized in that the fluid is an oil whose optical curvature is close to that of glass. Fiber optic introduction section.