JPS62251632A - Bathometer - Google Patents

Abstract

PURPOSE:To eliminate the need for a power source and to easily measure the depth of water without being affected by electro-magnetic induction, etc., by arranging end surfaces of a couple of optical fibers opposite each across a gap. CONSTITUTION:When an instrument is dipped in liquid such as water, the external hydraulic pressure rises with the depth of water and the force operates as shown by an arrow A to make an elastic member 9 deform elastically so that the end surfaces 1a and 2a of the optical fibers comes closer to each other. Consequently, the gap between the end surfaces 1a and 2a of the optical fibers decreases in width and light transmission loss due to the gap decreases. For the purpose, the light transmission loss of light transmitted from one optical fiber to the other due to the gap is measured to calculate the width of the gap between optical fiber sections and further variation in the external pressure. In this case, variation in the external pressure corresponds to the hydraulic pressure and the depth of water is calculated from the hydraulic pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a depth meter for measuring depth in a liquid such as water.

[Prior Art] Conventionally, as water depth gauges, water depth gauges such as a Bourdon tube type and a diaphragm type are known. In these conventional depth gauges, the obtained depth information is generally converted into an electrical signal and transmitted to a location, such as on the water.

[Problems to be Solved by the Invention] Therefore, conventional depth gauges require a power source to convert them into electrical signals, and the depth meter itself has to be large in size due to its power supply, or it is necessary to supply power from an external power source. I had to install metal lead wires for this purpose. Particularly when used in seawater, there was a problem of corrosion of metal lead wires, etc.

Additionally, when submerging depth gauges in multiple locations to measure the depth of each location, it is necessary to install metal lead wires in parallel between each depth gauge, which poses the problem of complicating the installation process. .

Furthermore, since the depth gauges are connected with metal lead wires, there is a problem in that good viscosity measurements cannot be made due to the influence of electromagnetic induction.

Therefore, an object of the present invention is to provide a water depth meter that does not require a power source, is not affected by electromagnetic induction, and can be easily installed.

Means for Solving Problem E] In the water depth gauge of the present invention, a pair of optical fibers are arranged so that their end surfaces face each other with a gap interposed therebetween. Elastic members are attached to the pair of optical fibers so as to connect them, and the third elastic member changes the width of the gap between the end faces of the pair of optical fibers in response to external pressure. It deforms elastically.

[Function] In the depth gauge of the present invention, the pair of optical fibers are connected by an elastic member, so when external pressure changes, the elastic member deforms elastically, and the width of the gap between the end faces of the pair of optical fibers changes. changes accordingly.

As shown in FIG. 2, the width of the gap between the optical fiber end faces,
What is the proportional relationship between the optical transmission loss ΔP due to the gap between the light transmitted from one side of the optical fiber to the other? By measuring the change in the optical transmission loss, the change in the width of the gap between the end faces of the optical fiber can be calculated. can do. Therefore, from the width of the gap between the optical fiber end faces determined in this way,
The external pressure exerted between a pair of optical fibers can be determined.

Embodiment FIG. 1 is a sectional view showing an embodiment of the present invention. In FIG. 1, a pair of optical fibers 1.2 have their ends 1.
A and 2a are arranged so as to face each other with a gap in between, and are fixed by optical fiber fixing portions 3 and 4, respectively. The optical fiber fixing members 3.4 each have a flange portion 3a.

4a is formed, and an outer vibrator 7 is provided so as to be sandwiched between the flange portions 3a, 4a. A bellows portion 7a is formed approximately at the center of the outer vibrator 7. By forming the bellows portion 7a, the outer vibrator 7
is made expandable. Inside the outer vibe 7,
An elastic member 9 made of a coil spring is arranged, and both ends of the elastic member 9 are fixed to the flanges 3a and 4a, respectively. A limiter vibe 8 is further arranged inside the elastic member 9, and inside the limiter pipe 8,
The ends of the optical fiber fixing elements 3.4 are respectively fitted. The limiter pipe 8 has both ends abutted against the flange portions 3a, 4a so as not to butt each other when the ends 1a, 2a come close to each other.

Grooves are formed in the portions where both ends of the outer vibrator 7 abut against the flange portions 3a and 4a, respectively, and O-ring packings 5.6 are fitted into the grooves, respectively. The O-ring packing 5.6 maintains the airtight condition inside the outer vibrator 7. Threads are formed on the outer periphery near both ends of the outer vibrator 7, and nuts 10, 11 are attached from both sides so as to fit into the threads.

When the depth gauge of this embodiment is submerged in a liquid such as water, the external water pressure increases as the depth increases. When the external water pressure increases, a force also acts in the direction shown by arrow A in Figure 1,
so that the end faces 1a and 2a of the optical fiber are close to each other,
The elastic member 9 is elastically deformed. As a result, the width of the gap between the end faces 1a and 2a of the optical fiber becomes smaller, and as shown in FIG. 2, the optical transmission loss ΔP due to this gap becomes smaller.

Therefore, by measuring the optical transmission loss ΔP due to the gap between the optical fibers and the light transmitted from one side of the optical fiber to the other, it is possible to calculate the width of the gap between the cross sections of the optical fiber and thus the change in external pressure. In this case, the change in external pressure corresponds to water pressure, and the depth can be calculated from the water pressure.

As described above, the depth meter of this invention converts depth into an optical signal and transmits it, so it does not require a power source and is not affected by electromagnetic induction unlike conventional depth meters. .

Further, since the water depth gauge of the present invention is connected by an optical fiber, it is also possible to use a number of stages of water depth gauges connected in series by optical fibers as shown in FIG. In this case, the light that has sequentially passed through the optical fiber of each depth gauge is finally transmitted to the measuring instrument. As a measuring device,
For example, a light backscatter meter can be used.

FIG. 4 is a diagram showing an example of a waveform observed by an optical backscattering measuring device. As shown in FIG. 4, the light reception level at each point on the optical fiber can be calculated using a light backscattering measuring device. The light transmitted through the optical fiber is transmitted with the received light level decreasing at a constant slope, but the received light level decreases particularly rapidly at the position where each depth gauge is installed. This rapid decrease ΔP4. ΔP2
...corresponds to the optical transmission loss due to the gap between the end faces of the optical fibers in each depth gauge. Therefore, by measuring each optical transmission loss, the change in the width of the gap between the end faces of the optical fibers can be determined, and from this value, the depth at which each depth gauge is located can be calculated.

In the embodiment, a coil spring was used as an example of the elastic member, but
The elastic member used in the depth meter of the present invention is not limited to such a shape.

Further, as the optical fiber used in the depth gauge of the present invention, any conventionally used optical fiber such as a plastic fiber or a silica fiber can be used. Further, in this case, it is desirable that the end face is subjected to a treatment such as a conventional end face treatment of an optical connector.

[Effects of the Invention] As explained in 1-1 below, the depth meter of the present invention converts the depth into an optical signal and transmits it, so it does not require a power source like conventional depth gauges and does not require electromagnetic induction. It is possible to measure accurately without being affected.

Furthermore, the depth gauges of the present invention can be installed in series by interconnecting them with optical fibers. Therefore, compared to the installation of conventional water depth gauges, each water depth gauge can be installed at a predetermined location much more easily.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the width of the rj1 gap between the end faces of optical fibers and optical transmission loss. FIG. 3 is a schematic configuration diagram showing an example of the connection state of the water depth meter of the present invention. Figure 4 shows
FIG. 3 is a diagram showing an example of an M1 waveform observed by a light backscattering measurement device. In the figure, 1.2 is an optical fiber, la and 2a are end faces of the optical fiber, and 9 is an elastic member. 1st figure 1r ship interval □n common □ Width 3rd figure 4th reverse ＃ (%)

Claims (1)

[Claims] (1) 1 arranged so that the end faces face each other with a gap in between
a pair of optical fibers; an elastic member that is attached to connect the pair of optical fibers and that is elastically deformed so as to change the width of the gap between the end faces of the pair of optical fibers in response to external pressure; A water depth gauge comprising: