JPS6217178B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of detecting information via an optical transmission body disposed in a band where information is to be detected.
This invention relates to an information detection method that can be applied to detecting fluid leaks in long transportation routes.

"Prior Art" The following methods have been provided as means for detecting oil leak accidents in oil transmission pipelines and the like.

One method is to install an electric cable along the pipeline whose dielectric constant changes depending on the presence of oil, and use this as an oil leak detection line.The change in impedance of the oil leak detection line (electrical cable) caused by oil leaks can be detected by installing an electric cable along the pipeline. This method detects oil leakage accidents by monitoring the cable end.

The other is a spring-structured detector in which the weight of oil leakage collected in the oil sump pushes down a spring-loaded rod to close an electrical contact for oil leakage indication.
This is a method of detecting oil leak accidents by placing them at each detection point along the length of the pipeline.

"Problems to be Solved by the Invention" In the former method described above, it is difficult to increase the change in cable impedance, so this must be converted into a pulse. Even if the detection signal is pulsed, Even if such a method is applied to a long oil pipeline, oil leak detection cannot be performed satisfactorily because the pulses do not travel far enough due to losses caused by the electric cable and external noise added to the electric cable.

In the latter method described above, expensive detectors must be installed at each of the many detection points set in the long pipeline, which requires a large number of expensive parts and requires a lot of work to install. This creates a diseconomie in terms of equipment.

Of course, even if the former method described above is applied to gas leak detection, the same problems as in the case of liquid leak detection will arise, whereas the latter method described above will
Since this is a leakage weight detection system, it cannot be applied to gas leakage detection.

In view of the above-mentioned problems, the present invention provides a method for optically detecting the presence or absence of various fluids in a specific area with high precision and sensitivity, and in particular, a method for detecting leakage fluids in various fluid oil passages. The purpose is to provide a method that can detect the leakage state and leakage location of a medium.

"Means for Solving the Problem" In order to achieve the intended purpose, the information detection method using the optical transmission body of the present invention is provided with a light transmitting section at one end and a light receiving section at the other end. , between the light receiving parts,
Regarding an optical transmission body in which a plurality of detection units are provided at mutually adjacent intervals, each of the detection units includes a loop-shaped auxiliary optical transmission unit having a light transmitting unit at one end and a light receiving unit at the other end, and It is composed of an optical branching end and an optical coupling end of the auxiliary optical transmission body, and an information intrusion space interposed between the outer peripheral surface of the optical transmission body, and each of the detection units is constituted by the detection unit. The mutual lengths of the sub-optical transmitters, the optical transmission speed characteristics of the sub-optical transmitters, or the degree of optical coupling between each sub-optical transmitter and the optical transmitter are different. A transmission body is arranged in a band where information is to be detected, and each of the detection units is distributed in each detection section of the information detection band, and in an optical signal transmission state of the optical transmission body from the light transmission unit to the light reception unit, When an information medium intrudes into one or more of the detection sections, the change in the optical signal due to the intrusion of the information medium is resolved by the light receiving section, and the information medium is present in the detection area into which the information medium has entered. detect what is happening.

"Function" The method of the present invention not only uses an optical transmission body, but also measures the mutual length of each sub-light transmission body constituting these detection units for a plurality of detection units provided on the optical transmission body. , or the optical transmission speed characteristics of each of the sub optical transmission bodies or the degree of optical coupling between each of the sub optical transmission bodies and the optical transmission body are made different, thereby causing differences in detection characteristics between the respective detection units. Because
Even if an information medium accidentally intrudes into the detection section, the light receiving section can catch a unique optical signal based on the unique function of the detection section, and by analyzing that optical signal on the light receiving section, information can be detected. It is possible to detect where the medium is present.

"Example" Examples of the method of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a passageway for transporting liquid, gas, etc., and this passageway 1 is constituted by a pipe body or the like.

The above-mentioned transport path 1 has a starting end 2 at one end for transportation,
The other end is a terminal end 3 for transportation, but depending on the case, one or the other of the starting end 2 and the terminal end 3 may be a relay end, so that the transport path 1 is connected to the required location. When laid, erected, or buried, the entire length in the longitudinal direction becomes the band in which leakage should be detected, that is, the information detection band L, and the information detection band L is divided into a large number of detection sections l ₁ , l ₂ , l ₃ . . . l _o-
It is divided into ₂ , l _o-1 , and l _o .

In the method of the present invention, an optical transmission body 4 is arranged along the information detection band L, and information such as a leakage object is detected via the optical transmission body 4.

The optical transmission body 4 is made of an optical fiber or an optical fiber cable, which is an aggregate of optical fibers, and has a light transmitting section 5 at one end and a light receiving section 6 at the other end.

The light transmitting unit 5 is mainly composed of a light source or an electricity-to-light converter (light-emitting diode) that converts electricity into light, and also includes a device that changes the driving current of the light-emitting diode according to the strength of the electric signal. They are combined or composed of a light-transmitting crystal that changes light emitted at a constant intensity in response to the intensity of an electrical signal, so that it can be freely modulated.

The light receiving section 6 includes an optical/electrical converter that converts light into electricity, a waveform analyzer, and the like.

Between the light transmitting section 5 and the light receiving section 6 of the optical transmission body 4,
A plurality of detection units 7 ₁ , 7 ₂ , 7 ₃ . . . 7 _o-2 , 7 _o-1 , 7 _o are provided corresponding to each of the detection sections l ₁ to lo described above _.

FIG. 2 shows the detection unit 7 ₁ extracted from among the detection units 7 ₁ to 7 _{o .}
is constructed using an auxiliary optical transmitter 8 which is made of the same material as the optical transmitter 4 and has a loop shape such as an Ω type.

More specifically, the detection section ₇₁ is constructed by bringing the optical branching end 9a and the optical coupling end 9b at both ends of the sub optical transmission body 8 close to the optical transmission body 4, and the branching end 9a and the optical coupling end 9b are arranged close to each other. Information intrusion spaces 10a and 10b are interposed between and the optical transmission body 4, respectively.

The information intrusion spaces 10a and 10b are normally filled with a gas, such as air, forming the atmosphere of the information detection zone L.
A liquid having a light transmission effect in a and 10b, or
When gases that change the optical transmission characteristics enter,
A part of the optical signal passing through the optical transmission body 4 is branched from the optical branching end 9a to the sub optical transmission body 8, and the branched optical signal is transmitted from the sub optical transmission body 8 to the optical transmission body via the optical coupling end 9b. It will be reconnected to the 4th side.

In the method of the present invention, the lengths of the sub optical transmission bodies 8 in each of the detection units 7 ₁ to 7 _o are made different, or each of the detection units 7 ₁ to 7 _o is configured with sub optical transmission bodies 8 having different optical transmission speeds. Alternatively, by varying the degree of optical coupling by the optical branching end 9a of the sub-light transmitter 8, the detection characteristics (light transmission characteristics) of each of the detection sections ₇₁ to _7o having the above-mentioned functions can be set. Make a difference.

When information detection according to the method of the present invention is carried out based on the technical contents described above, an optical signal is sent from the light transmitting section 5 of the optical transmission body 4 to the light receiving section 6, and its state is monitored by the light receiving section 6. , performs information detection using leakage from the feed path 1 as an information medium.

In this case, the light signal is one in which the driving current of the light emitting diode is changed according to the strength of the electric signal, and the intensity of the light is thereby changed to a predetermined value, or the light is emitted at a constant intensity. A so-called optical modulation signal is used, in which light is passed through a special crystal to which an electric field is applied, thereby changing the light in accordance with the electric signal.

In such information detection, a state in which there is no leakage accident in the feed path 1 is considered normal.

In this state, each detection unit 7 ₁ to 7 of the optical transmission line 4
The information medium (leakage) from the transmission path ₁ will not enter into
There is no change in the optical signal transmitted to the light receiving section 6, and the normal state of the light receiving section 6 can be known.

On the other hand, in the above information detection, if a leakage accident occurs in any of the detection sections l ₁ , l ₂ , l ₃ ...l _o-2 , l _o-1 , l _o of transport path 1, Information intrusion space 10 of the detection unit 7 ₁ in the detection section (for example l ₁ )
The leaked material enters a and 10b as an information medium, and a part of the optical signal of the optical transmission body 4 is transmitted through the information medium from the optical transmission body 4 → the optical branching end 9a → the sub optical transmission body 8 → The optical signal is branched and coupled in the order of the optical coupling end 9b → the optical transmission body 4, and the optical signal that reaches the light receiving unit 6 in a state different from the normal state is transmitted to the light receiving unit 6.
The analysis is displayed on the side and the leakage accident is detected.

This point will be explained in detail below.

When a part of the optical signal transmitted in a modulated state from the light transmitting section 6 is optically branched and optically coupled at the detection section ₇₁ , the optical signal passes only through the optical transmission body 4 and the sub optical transmission body 8. An optical signal passing through is generated.

The former optical signal passing only through the optical transmission body 4 and the latter optical signal passing through the auxiliary optical transmission body 8 are received later than the former signal by the amount that the latter optical signal bypasses the auxiliary optical transmission body 8. Since these two types of optical signals reach the light receiving section 6 side, they have a relative order of priority based on the time of arrival at the light receiving section 6 side.

Compared to the original signal, the former optical signal that arrives first at the light receiving section 6 side has a lower amplitude by the amount that the latter signal is generated, so by analyzing and displaying this on the light receiving section 6 side, , the occurrence of the above accident can be detected,
On the other hand, since the characteristics of each of the detection units 7 ₁ to 7 _o are different from each other as described above, the amplitude reduction at this time is also determined depending on each detection unit, and therefore, according to the above analytical display, the detection unit 7 ₁ At the same time, it was discovered that the accident occurred in a certain detection zone.

Furthermore, if a leakage accident occurs simultaneously in multiple detection sections (for example, l ₁ and l ₂ ), the optical signal passing through the optical transmission body 4 is divided into two optical branches similar to those described above at the detection sections 7 ₁ and 7 ₂ . , optical coupling occurs, but in this case also the detection unit 7
Since the optical signals whose amplitudes have been reduced according to the respective characteristics of ₁ and 7 ₁ arrive at the light receiving section 6 first, it is clear that these amplitude reduction rates are due to both the detection sections 7 ₁ and 7 ₂ . It is only necessary to perform the analysis on the light receiving unit 6 side, and thus accidents that occur simultaneously in the detection sections l ₁ and l ₂ can be detected.

In the above embodiment, only the first-arriving optical signal with a reduced amplitude is analyzed on the light-receiving section 6 side to detect the desired information. By these means, such as analyzing the optical signal that arrives or the composite signal of both the first and second arriving optical signals on the light receiving unit 6 side, or further analyzing the time difference between the first arriving optical signal and the second arriving optical signal, etc. Information may be detected by analyzing changes in the frequency characteristics.

The above is an embodiment in which the leakage is detected using the leakage material from the transmission path 1 as an information medium.In such information detection, an outer cylinder covering the transmission path 1, the optical transmission body 4, etc. is placed in the detection area L. Furthermore, partition walls may be provided for each of the detection sections l ₁ to _{l o} in the outer cylinder.

Examples of applications other than leak detection of the method of the present invention include determining whether a liquid or gas has entered a specific area as an obstacle, or whether an information medium such as a liquid or gas sent from a certain point has reached a predetermined point. Examples of information detection include whether the vehicle has passed or not.

In the method of the present invention, when performing information detection over a wider area, a plurality of optical transmission bodies 4 may be arranged in parallel, and changes in the optical transmission state in each optical transmission body may be combined.

An example of a gaseous information medium is _CO2 gas, which absorbs infrared light.
For example, when CO ₂ gas enters the information intrusion spaces 10a and 10b, the light of the corresponding wavelength is absorbed, that is, the branching characteristics change, and the output of the detection section described above decreases. Predetermined information can be detected by analyzing it on the side.

"Effects of the Invention" Since the information detection method using the optical transmission body of the present invention is as described above, the following effects can be obtained.

One of them is that the target information is detected by passing light through the optical transmission body, so compared to electrical detection means, there is almost no external influence such as noise, and
There is an immediate response that allows information detection to be performed immediately upon a change in the optical transmission state, and since information detection is performed when an information medium enters each detection section, malfunctions are unlikely to occur.

The other method is to make each sub-light transmission body have different detection characteristics by making the length, optical transmission speed characteristics, optical branching degree, optical coupling degree, etc. of each sub-light transmission body different. Utilizing these differences in detection characteristics, a single light-receiving section can detect the presence and location of information, and even detect information arriving in multiple detection zones simultaneously. In addition to the above-mentioned points, various types of information detection can be carried out with high accuracy and sensitivity, and moreover, economically.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing an embodiment of the information detection method according to the present invention, and FIG. 2 is an enlarged explanatory diagram showing an example of the detection section in the same. DESCRIPTION OF SYMBOLS 1...Transmission path, 2...Starting end of a transmission path, 3...Terminal end of a transmission path, 4...Optical transmission body, 5...Light transmission part, 6...Light receiving part, 7
₁ to _7o ...detection section, 8...sub-optical transmission body, 9a...optical branching end, 9b...optical coupling end, 10a to 10b...information intrusion space, L...information detection band, _l1 to _lo ...detection section.

Claims (1)

[Claims] 1 Regarding an optical transmission body that is equipped with a light transmitting section at one end and a light receiving section at the other end, and a plurality of detecting sections are provided at mutually adjacent intervals between the light transmitting section and the light receiving section, each of the above-mentioned A detection section is provided between a loop-shaped sub-light transmission body having a light transmitting section at one end and a light-receiving section at the other end, an optical branching end and an optical coupling end of the sub-light transmission body, and the outer peripheral surface of the optical transmission body. and an intervening information intrusion space, and for each detection section, the mutual length of each sub-light transmission body constituting these detection sections, or the mutual optical transmission speed of each sub-light transmission body. The characteristics or degree of optical coupling between each of the sub optical transmission bodies and the optical transmission body are different, and the optical transmission bodies are placed in the band where information is to be detected, and each of the above-mentioned detection units is connected to the information detection band. distributed in each detection section, and when an information medium enters one or more of the detection sections in an optical signal transmission state of the optical transmission body from the light transmitting section to the light receiving section, the optical signal due to the intrusion of the information medium An information detection method using an optical transmission body, in which the change in the information medium is analyzed on the light receiving section side to detect that the information medium is present in the detection area into which the information medium has entered.