JP3128340B2 - measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber in which an optical signal is incident from an incident end which is one end of an optical fiber disposed in a region to be measured, and is returned to the incident end from any place in the optical fiber toward the other end. The present invention relates to a measuring device that analyzes incoming backscattered light and measures the temperature, humidity, temperature distribution, or the like at an arbitrary location in the measured area, and particularly relates to a measuring device that improves the positional resolution of the measuring location.

[0002]

2. Description of the Related Art A thermometer using an optical fiber of this type includes an OTDR (Optical Time Domain Reflectometry).
Type thermometer and OFDR (Optical Frequency Domain Re)
flect-ometry) type thermometer. Both of these thermometers use the Raman (Raman) scattering method and the Rayleigh (Rayleigh) scattering method. The difference between these two methods is that Raman scattering has a scattering wavelength different from that of emitted light, while Rayleigh scattering is scattering. The major difference is that the wavelength is the same as the emission light. Here, an example in which an OTDR thermometer is used as a thermometer and a Raman scattering method having high temperature measurement sensitivity is used will be described. This OTDR thermometer is based on two principles: temperature measurement using Raman scattering in an optical fiber and position measurement using an optical pulse reflection method.

[0003] Raman scattering is a physical phenomenon in which light having a wavelength different from that of incident light is scattered when a photon incident on a substance interacts with an optical mode of molecular vibration and causes inelastic collision. There are two types of Raman scattered light, one shifted to the long wavelength side (Stokes light) and the other shifted to the short wavelength side (anti-Stokes light) with respect to the incident light. Assuming that λ and the wavelength of the Stokes light are λ _S and the wavelength of the anti-Stokes light is λ _A , the following relationship is obtained. ν = (1 / λ) − (1 / λ _S ) ν = − (1 / λ) + (1 / λ _A )

Here, ν is a wave number. The wave number is a quantity determined by the properties of the material and is called Raman shift. The intensity of the Raman scattered light depends on the temperature. Assuming that the ratio of anti-Stokes light to Stokes light at temperature T is R (T),
The following relationship holds: R (T) = (λ _S / λ _A ) ⁴ exp (-hcv / kT)

Where h is Planck's constant, c is the speed of light, k
Is Boltzmann's constant. In Raman scattering, it is known that the scattering intensity of anti-Stokes light greatly changes with temperature, and this is used for temperature measurement. On the other hand, O
In the TDR method, pulse light is incident from one end of an optical fiber,
The distance is measured by measuring the time of the component that is backscattered and returned in the medium of the optical fiber. Therefore, the temperature distribution can be measured by combining the two methods described above.

It has been considered that this Raman scattering is difficult to use for temperature measurement because it is affected by minute substances and various molecules in the environment in the air or gas environment. With the development and technological development of optical fiber, various uses of the optical fiber have been studied,
As part of this, research and development on the use of thermometers has been promoted. In particular, it has been found that the optical fiber is suitable for temperature measurement, though gradually, since only the fixed fiber component exists unlike the air or gas environment. The OTDR performs temperature measurement using a high-speed pulse, whereas the OFDR performs temperature measurement using frequency-modulated light.

However, at present, in the OTDR type thermometer which is a representative model to which this Raman scattering method is applied, the position resolution length Lt of the optical fiber temperature measuring section is 20 m, the minimum measuring temperature Tb is 5 ° C., and the maximum measuring temperature is Although Tc is 150 ° C and the maximum measurement length Lmax is in a measurement range of 1 km (corresponding to 0.1 m at 1 GHz, the resolution is limited to about 0.1 m). Lt is 0.5 m, Tb is −50 ° C., Tc is 500 to 600 °
It is considered that C and Lmax are improved to about 10 km. Note that a Rayleigh scattering method may be used, and the OTDR type thermometer including these scattering methods will be referred to.

Therefore, at present, since Lt> 20 m, it is difficult to measure the temperature of a point, and only research on measuring the temperature distribution along the optical fiber has been made. Moreover, since the backscattered light from each point on the long optical fiber is weak and contains noise, the backscattered light obtained by repeatedly emitting an optical signal several thousand to tens of thousands of times is obtained. Are averaged to remove noise and measure the required signal, but it is very difficult to measure with high fidelity.

The OTDR originally has a function of detecting a position, but an optical signal is incident from a light source to an incident end of an optical fiber, and Raman scattering generated in the optical fiber due to the incidence of the optical signal. Among them, it is configured such that the temperature detection position is measured from the time until the backscattered light returning toward the incident end direction returns.However, due to the difference and the configuration of the minute components constituting the optical fiber, the optical fiber Is often different from the case where the length from the outside to the temperature detection position is measured by the length meter. In addition, since the optical fiber, which is the temperature measuring part of the OTDR, adapts to the mounting location and changes its shape flexibly, it is very difficult to measure the length of the optical fiber from outside the optical fiber.

Therefore, the present inventor provided reference signal applying means at various points on the optical fiber, and measured the transmission time of the backscattered light scattered from the portion of the optical fiber corresponding to the reference signal applying means. This has led to the development of a measuring device for measuring the position of an actual measuring portion of an optical fiber (Japanese Patent Application No. 63-326149).

The purpose of this measuring device is to provide a welded portion 3 at a portion other than the measuring portion 2 of the optical fiber 1 as shown in FIG. 25A, or as shown in FIG. By providing a strong bent portion 4 in a portion other than the measurement portion 2, the position is known while utilizing the minute attenuation characteristic (c in FIG. 25) at the weld portion 3 or the bent portion 4.

Another method is to form a reference temperature detecting section 5 in a portion other than the measuring section 2 of the optical fiber 1 as shown in FIG. This is a method of giving a reference temperature by means (not shown). For example, as shown in FIG. 2B, the measuring unit 2 of the optical fiber 1 is placed in a furnace, while the other than the measuring unit 2 This is the time when a reference temperature is applied by setting the out-of-furnace portion, which is a portion, as the reference temperature detection unit 5. Further, FIG.
Is provided with a reference temperature applying means 6 such as an electric heater or a steam heater at a portion other than the measuring section 2 of the optical fiber 1 and is heated to a predetermined temperature. At this time, the temperature as shown in FIG. Characteristics are obtained.

[0013]

Therefore, the reference temperature applying means 6 is applied to a portion other than the measuring portion of the optical fiber 1 as described above.
Is installed, the detection level of the backscattered light due to the incidence of the light pulse changes, so that the position (reference position) of the optical fiber 1 at a substantial portion of the reference temperature applying means 6 can be known.
From this reference position, the installation location of the measurement section and its temperature can be measured relatively.

However, as shown in FIG. 25 (a), for example, in a case where a large number of portions of the optical fiber 1 are welded, that is, in the case of a welded marker method, the attenuation of light cannot be ignored, and it is equivalent to forming the welded portion 3. It takes time and effort. Also, in the case of FIG. 2B, the attenuation cannot be neglected similarly, and attention must also be paid to the breakage of the optical fiber 1, so that it cannot be applied to a place where vibration or temperature change is severe.

Next, in the case of FIG. 26A, a reference temperature applying means is provided for each of the reference temperature detecting sections 5 of the optical fiber 1, so that it is effective for high-precision temperature measurement. Such a reference temperature applying means only increases the positional accuracy, and is a very luxurious and expensive system. further,
In the case of FIG. 3C, since the portion other than the measuring section of the optical fiber 1 is heated by the reference temperature applying means 6, it is necessary to draw in electricity or a steam pipe, which causes an extra cost. There is.

The present invention has been made in view of the above circumstances, and a reference position signal can be easily obtained by simply covering a portion other than the measuring portion such as an optical fiber with a material having a different heat transfer coefficient from the optical fiber. It is an object of the present invention to provide a measuring device that contributes to an improvement in resolution.

Another object of the present invention is to form a bundle in order to increase the sensitivity of a measuring portion such as an optical fiber or a reference position marker portion. At this time, it is possible to form the bundle without twisting. Accordingly, it is an object of the present invention to provide a measuring apparatus which improves the position resolution and arranges a measuring section or a reference position marker section at a measuring point in a measurement area while easily producing the measuring section or the reference position marker section.

Still another object of the present invention is to make it possible to easily obtain known data required for measurement before actual use, and to quickly obtain a bundle of optical fibers, for example, a measuring unit under a certain standard. It is an object of the present invention to provide a measuring device that forms a measurement point and can be arranged at a measurement point in a measurement area.

[0019]

In order to solve the above-mentioned problems, an optical signal from a light source is incident on an input end of an optical fiber, and the optical signal is incident on the optical fiber. Measurement for measuring the temperature, humidity, temperature distribution, etc. of the measurement target region based on the time required for the backscattered light toward the incident end to return from the Raman scattering generated from the inside and the intensity of the returned signal. In the device,

A required portion of the optical fiber or the sheath containing the optical fiber is used as a measuring portion for measuring temperature, humidity, temperature distribution, or the like, and an appropriate portion other than this measuring portion or any of a plurality of measuring portions is used. The measuring unit is provided with a heat-transfer heterogeneous material surrounding portion or a heat-transfer contact portion that covers a material having a different heat transfer coefficient from the optical fiber, the sheath, or the like directly or in a state of a hollow medium. This is a measuring device that obtains a reference position signal by using a temperature difference between the measurement unit generated when a temperature change is applied and a measurement unit in a portion covered with a substance having a different heat transfer.

In the heat-defective transmission surrounding portion which is a heat-transfer heterogeneous material, a heat-defective transmission body such as plastics or a heat insulating material, a hollow medium, or the like is used. A reference position signal having a predetermined specific meaning (for example, a representative reference position or the like) is obtained by changing the length or the interval between a plurality of adjacent heat failure transmitting and surrounding portions.

According to a fifth aspect of the present invention, an optical signal from a light source is incident on an incident end of an optical fiber, and the incident end of Raman scattering generated from within the optical fiber due to the incident optical signal. a measuring apparatus for measuring the temperature of the measurement area, the humidity or temperature distribution or the like based on the strength of the signal has returned to the time until returning of backscattered light directed toward the optical fiber or optical fiber A slack portion is formed at the required portion of the sheath for
Wound using a plurality of bundles or bobbin wound as Sowase in the least <br/> be one turn or more to substantially close the equidistant portions each other from the center of the U-turn portion of the optical fiber is a Rumi tip Measuring an arbitrary number of bundles out of multiple bundle measurement units
The heat transfer coefficient differs from the optical fiber and the sheath in the part
Provide a thermal failure transmission surrounding area covered with a substance, and
The measurement part and the front part, which are generated when motion or temperature change is given
Temperature between the measuring part and the part covered with a substance with different heat transfer coefficient
This is a configuration in which a reference position signal is obtained using a difference in degrees .

In the bobbin, a U-turn groove portion of the optical fiber is formed in the bobbin core, and the U-turn portion formed in the optical fiber or the sheath containing the optical fiber can be hooked. .

Further, according to the present invention, a color, a character, a numeral, a position, and a distance for optically measuring a mechanical distance and an optical position in a required portion of the optical fiber or a sheath containing the optical fiber are provided. After applying a picture or other sign or a magnetic paint film and performing the mechanical distance and optical position measurement, any of a plurality of bundle measuring units having a predetermined number of turns using the sign or the magnetic paint film as a guide. Measuring a bunch of numbers
The optical fiber and the sheath have different heat transfer coefficients
A thermal failure transmission enclosure to cover the temperature of the part to be measured
The measurement unit generated when a fluctuation or a temperature change is given;
Between the measurement part of the part covered with the different material of the heat transfer coefficient
In this configuration, a reference position signal is obtained using a temperature difference .

[0025]

Therefore, the inventions corresponding to the first to fourth aspects take the above-described means, so that necessary portions other than the measuring portion of the optical fiber or the sheath in which the optical fiber is housed have different heat transfer coefficients. If the thermal failure transmission surrounding portion covered by the failure transmitting body is provided, when the temperature of the measured area changes or when the temperature is changed, it corresponds to the measuring portion of the optical fiber or the sheath and the thermal failure transmission surrounding portion. Since the temperature difference from the optical fiber portion occurs, the detection level of the backscattered light changes due to the temperature difference, whereby the optical fiber portion corresponding to the heat-defective surrounding portion, that is, the reference position, can be known. Can be measured at the location where the measuring section is installed and the temperature at that location.

Next, a fifth aspect of the present invention is to form a U-turn portion of an optical fiber in a required portion of an optical fiber or a sheath containing the optical fiber, for example, a portion to be a measurement portion. If the bundle is wound by attaching and winding the portions approximately equidistant from the center of the U-turn portion so as to approach each other, the winding start and end portions of the winding portion of the optical fiber become isothermal, and the front and rear portions of the U-turn portion become Is targeted with the U-turn point as the target point. Correcting the measurement results using this isothermal temperature and the target conditions can significantly improve the measurement accuracy, and also allows the optical fibers to be bundled without twisting. It is very easy to install at each measurement point in the area.

Further, when the U-turn portion of the optical fiber or the like is wound around the bobbin, if the U-turn groove is formed in advance in the bobbin core, the U-turn portion of the optical fiber or the like can be hung on the U-turn groove of the bobbin. And a bundle can be formed very quickly.

Further, according to the present invention, in order to measure a mechanical distance and an optical position in advance, a required portion of an optical fiber or a sheath containing an optical fiber is provided with colors, characters, numerals, and characters. Since a picture or other sign or magnetic paint film is attached, not only can the mechanical distance and optical position be measured in this state, but also a bundle to be used as a measuring unit can be formed using the sign or magnetic paint film as a guide. ,
Alternatively, after forming the bundle, the reference position signal can be obtained by covering the bundle with the thermal failure transmitting body.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of measurement of a thermometer using an OTDR, which is a base for describing the apparatus of the present invention, will be described with reference to FIGS.

Now, for example, as shown in FIG.
Light source 1 such as a laser oscillation device or a light emitting diode that generates light
1 generates an optical pulse S, and outputs the beam splitter 12 (beam
Device that performs the same function as the beam splitter
The light is referred to as a beam splitter (including the optical splitter).
When the light enters the incident end of the fiber 13, the optical fiber 1
3, the transmission position of the light pulse S, for example, t¹ , ……, t
^n-1 , Tⁿ Ν = (1 / λ)-(1 / λ_S) Ν =−(1 / λ) + (1 / λ_A) Raman scattering at different frequencies occurs one after the other,
Position t¹ , ..., t^n-1 , Tⁿ Backscattered light from
The beam splitter 12
The signal is branched or introduced into the signal processing device 14.

Therefore, in the signal processing device 14, after the light pulse S is generated, each position t ₁ ,..., T _n−1 , t _n
Temperature T1, which is the intensity of backscattered light scattered from
.. Tn-1 and Tn are detected, and if T1 = T2 =.
When 1 = Tn, the signal level decreases as the temperature at a farther position increases as the loss due to transmission increases.
That is, the measurement result by the signal processing device 14 is as shown in FIG. Since the signal processing device 14 issues a light pulse emission command to the light source 11, in the present embodiment, an electrical signal capable of processing the emission command and the backscattered light scattered from the optical fiber 13 and returned. Is converted to, the return time of the backscattered light is measured based on the launch command time, the intensity of the backscattered light is measured on the measurement time axis, and the speed of light in the optical fiber is calculated as known, The temperature is measured from the measurement position and the intensity of the backscattered light at the measurement position.

That is, this measurement principle is a method of measuring the time from the generation of the optical pulse S to the return from the optical fiber 13 to know where the Raman scattering has occurred. Effective for long optical fibers.

On the other hand, in the OFDR, when an AC continuous wave (modulated wave) is used, the Raman scattering is determined at any position due to the phase shift between the AC waveform optical signal and the AC waveform optical signal returning from the optical fiber. This is a method of knowing whether or not an error has occurred. In this case, even a relatively short optical fiber can be accurately measured. In each case, the temperature is measured from the magnitude of the backscattered light. Other wavelength lambda of the light pulses S generated from the light source 11 in this backscattered light, λ _A, λ since _S etc. are mixed, lambda by characteristic filter or the duplexer of the signal processing apparatus 14 _A, lambda Separate _S and measure temperature. λ
_{Since A} has high sensitivity to temperature and λ _S has low sensitivity to temperature, division is performed as λ _A / λ _S , and λ _S is used to compensate for fluctuations in the light source and the transmission path. By performing such compensation, light amount change of the light source, without greatly affected by the loss change of the transmission path, it is possible to perform temperature measurement with high sensitivity using a lambda _A. On the other hand, it is desirable to use λ _A and λ _S also for the temperature at which the position is detected.
Note that a beam splitter is not required when an element that functions as both a light source that generates an optical signal and a detector is used.

FIG. 3 shows a specific example of the signal processing device 14. That is, the signal processing device 14
Has a CPU 141 that outputs various commands based on a sequence program, receives an operation command from the CPU 141, and outputs an optical pulse having a wavelength λ from the light source 11 through a beam splitter 12 including, for example, two prisms. When the light enters the optical fiber 13, the backscattered light including the wavelengths λ, λ _A , λ _S, etc., of the Raman scattering generated inside the optical fiber 13 and returning to the light incident end side is converted into a characteristic filter or a duplexer 142. Incident on.

When 142 is a characteristic filter, a filter that passes one of the wavelengths λ _A or λ _S is used. The temperature is measured at λ _A as described above, and the variation of the light source or the transmission line is measured at λ _S. As detected, for example, λ _A / λ _S
To a compensated process quantity corresponding to the temperature. Alternatively, a filter that passes both λ _A and λ _S is used, and λ _A and λ _S are used as the temperature signal.

On the other hand, when 142 is a duplexer, λ _A , λ
After splitting into light of wavelength _S , the subsequent optical-electrical converter 1
At 43 and 144, they are converted into electric signals. Then, the electric signal converted by the optical-electrical converter 144, that is, the signal caused by the Raman scattering is sent to the high-speed time series processing means 146 directly or through the switch circuit 145, where the operation from the CPU 141 to the light source 11 is performed. Time (position) based on the timing signal input in synchronization with the command output
And the signal intensity corresponding to the temperature for that time is measured and stored sequentially in the built-in memory. A data processing unit 147 performs desired data processing using the data stored in the high-speed time-series processing unit 146 and, if necessary, the data of a file 148 in which a temperature transmission source or the like of the measured area is mapped. is there.

By the way, a measuring device as a thermometer using this kind of OTDR is, for example, as shown in FIG. Lay in a meandering order,
Further, the optical fiber 13 is laid in a meandering shape in a direction orthogonal to the end by turning the end of the optical fiber 13 and the so-called optical fibers 13 are arranged in a mesh form. The distribution interface and the like can be measured. Therefore, each crossing portion of the optical fiber 13 is called a measuring unit 16,. For the measurement of humidity, a dry bulb and a wet bulb are provided, and the interface to be measured by measuring the temperature of the dry bulb and the wet bulb is a temperature difference between the upper and lower sides of the interface or a heating fiber. It is measured using the temperature difference caused by the difference.

However, since optical pulses are transmitted at a very high speed, it is indispensable to upgrade electronic circuits in order to increase the resolution such as position and temperature. Although a considerable period of time is required, in order to increase the process measurement amounts such as temperature, humidity, and temperature distribution with high sensitivity and to increase the position resolution, a plurality of optical fibers 13 are used for measuring the temperature and position of the optical fiber 13. If you place it around the turn, it will come closer to that requirement.
In other words, the optical fiber 13 is placed only at a necessary place, and the optical fiber 13 is placed at a measurement place such as a temperature and a position.
If the bundle of the optical fibers 13 is formed and arranged in a matrix arrangement or three-dimensional coordinates, the portion of the optical fiber 13 to be measured becomes longer, and if the obtained backscattered light is averaged, the measurement sensitivity,
Resolution can be increased.

However, in practice, a length that is easy to arrange is set, and if the total length is extremely long, the optical fiber 13 is divided into a plurality of pieces, and the optical fiber 13 is cut at a time without cutting the optical fiber 13 as a unit. It is very difficult to create a bundle while winding it around a bobbin or the like in a written state to form a matrix arrangement or a three-dimensional coordinate arrangement, even though it is one unit. Inevitably, the optical fiber 13 is twisted, the optical characteristics are changed, and the practicality is poor. Next, an embodiment of the apparatus of the present invention to which the above-described measurement principle is applied will be described. First, an embodiment of the invention corresponding to claims 1 to 4 will be described with reference to FIGS.

FIG. 4 is a view showing an embodiment of the apparatus of the present invention. This measuring device connects the optical fiber 13 to the area 15 to be measured.
The optical fiber 13 is laid in a predetermined manner so as to form a one-stroke, in a meandering manner in a predetermined order, and is further folded back at its end to form a meandering direction in a perpendicular direction. Are arranged in a mesh pattern, and the optical fiber 13
Are defined as measuring sections 16 for measuring temperature and the like.

As a marker indicating the reference position of the optical fiber 13, a suitable portion other than the measuring portion of the optical fiber 13, for example, a plastic or the like at all or a necessary portion between both intersections in the X direction and the Y direction is used. Defective heat transmission surrounding portions 17 (A), 17
By providing (B),..., The reference position signal of the corresponding portion of the optical fiber 13 is obtained.

Therefore, according to the configuration of the embodiment as described above, the heat failure transmitting and surrounding portions 17 (A), 17 (B),.
The position (known position) of the optical fiber 13 covered by... Is grasped, and when the temperature of the measured area 15 is rapidly increased in this state, the temperature rise of the measured area 15 corresponds to the temperature rise. The temperature rise of the heat transmission member of the optical fiber 13 is delayed. As a result, the reception level of the backscattered light reflected from the inside of the optical fiber 13 after the irradiation of the optical fiber 13 is as shown in FIG. In other words, the reference positions A and B of the thermal failure transmission surrounding portions 17 and 17 are determined from the recesses of the reception time and the delay of the temperature rise and the known signal position.
Can be accurately known, and if the reference position is known, the measuring units 16 and 1 of the optical fiber 13 can be determined from the reference position.
The position and temperature of 6, ... can be easily grasped. Moreover,
It is possible to know the reference position without providing a welding portion and a reference temperature applying means as in the related art.

Next, FIG. 6 is a view showing another embodiment of the apparatus of the present invention. In this device, the optical fibers 13 are arranged in a meandering manner in a tank 20 in a vertical direction as shown in FIG. At this time, the optical fiber 13 in the tank 20 is mounted in a stainless steel sheath. Then, by covering a required portion other than the measuring portion of the optical fiber 13 or a corresponding portion of the stainless steel sheath with the defective thermal transmission body, the defective thermal transmission surrounding portions 17,... Are formed. Further, a heat exchanger 21 for feeding heated steam is provided at a required position in the tank 20.

In this state, the process fluid is introduced into the tank 20 and the process fluid is heated by sending the heating steam to the heat exchanger 21, and then the heated fluid is guided to the outside. Measuring unit 16,
, The temperature inside the tank is measured, and based on the reference position obtained from the corresponding heat-defective transmitter portion of the optical fiber 13, it is possible to know each installation location of each measuring section 16,. Thereby, the temperature distribution in the tank can be obtained. 22 is a stirrer.

When a large number of heat failure transmitting surrounding parts 17,... Are provided at a position to be a reference on the optical fiber 13, the position of the heat defective transmitting surrounding parts 17,. For example, as shown in FIG. 7 (a), a relatively long heat failure transmitting and surrounding portion 17a, 17a is provided at a corresponding portion of the optical fiber 13 or the like which should be a representative reference position, so that the reference reference positions are AA and BB. Reference positions 17 (A) and 17 (A) shown in FIG.
(B),... Or by changing the number or interval of a plurality of adjacent heat failure transmitting and surrounding portions 17,... As shown in FIG. The meaning of the position may be given.

Therefore, according to the above-described configuration, the portion to be the reference position of the optical fiber 13 inside the tank is not led out of the tank and used as the reference point as in the prior art. You can know.

Although plastics is used as the heat transfer medium in the above embodiment, a heat insulating material may be used to further increase the heat insulating efficiency. Many of these heat insulating materials generally have a porous structure. Among them, inorganic materials include asbestos, glass wool, fine powder minerals, and insulating bricks. On the other hand, organic materials include various fibers, cork materials, and foam plastics. and so on. Further, examples of the organic-inorganic composite include a heat-insulating fine powder mineral and a plastics molded product in which short fibers are dispersed.

In addition, a hollow body made of metal, non-metal, or the like may be used as the thermal failure transmitting body. FIG. 8 is a view showing an example of the heat failure transmission surrounding portion 17b using such a hollow heat failure transmission body. That is, FIG.
A hollow thermal failure transmitting and surrounding portion 26 made of, for example, stainless steel or plastic is attached to a required location on the sheath 25 in which the interior is mounted.

At this time, if the medium having the heat insulating effect is filled, for example, into the inside of the hollow-type heat-defective transmission surrounding portion 26, the heat insulating efficiency is improved. For example, the medium may be any of a gas containing a gas, a liquid, a solid, a mixture, or a vacuum. Also, the hollow thermal failure transmission surrounding portion 26 is shown in FIG.
As shown in FIG.
5a and curved lids 26b, 26b whose insides are mirror-finished so as to be located on both sides thereof are arranged, and the lids 26b, 26b are joined to the cylindrical body 26a by welding, bonding, welding, or the like to form a hollow shape. May be.

This heat transfer delays the heat transfer while effectively utilizing the three elements of conduction, radiation and convection. Among them, in the case of a vacuum, there is no action such as conduction or convection which is transmitted through a gas such as a gas, and only radiation occurs. Although there is conduction in which heat is transmitted outside the hollow heat-defective transmission surrounding portion 26,
The heat transfer time to the center of the hollow heat-defective transfer surrounding portion 26 is very long. On the other hand, in the case of gas, conduction,
Although there is radiation and convection, it is much slower than when the hot liquid directly hits the sheath 25.

Next, FIG. 9 is a diagram showing a configuration in which the measuring sections 16, 16,... Of the optical fiber 13 are wound a plurality of times in order to increase the temperature detection sensitivity. The measurement units 16a, 16a,... Having the winding portions are arranged in a planar, three-dimensional, or random manner.

Further, the apparatus of the present invention also provides the thermal failure transmission surrounding portion 17 at a portion other than the measuring portion 16 having the winding portion, with respect to the optical fiber 13 having the above-described arrangement, and sets the reference position. What you get.

Further, as shown in FIG. 10, a reference position is obtained by selecting an arbitrary one of the measuring units 16a,... Is also good. In this case, the measuring unit 16a is a non-measuring unit.

In the above embodiment, the wound portion is formed directly on the measuring portion 16a, 16b,... Of the optical fiber 13.
For example, when the optical fiber 13 is housed inside the sheath 25, the wound portion is formed together with the sheath. At this time, for example, as shown in FIG. 11, if each of the optical fiber winding portions is surrounded by a stainless sheath container 25a, the optical fiber winding portion is composed of a heat delay container portion and a non-container portion having good heat transfer. The portion may be used as a reference position, and the heat delay container may be used as a measuring portion.

Next, an embodiment of the invention according to claims 5 and 6 will be described with reference to FIGS. The basis of the present invention is that a U-turn portion of an optical fiber is formed at a required portion of the optical fiber 13, and the U-turn portion is wound at least one or more times to form a bundle to increase detection sensitivity. In addition, winding is performed without generating twist.

First, in FIG. 12, a large number of measuring parts 33 of the optical fiber 13 are arranged at required positions in the measured area 32 in the tank 31. At this time, the sheath 25 including the optical fiber 13 is mounted on the bobbin 34. Wound and optical fiber 1
No. 3 is wound with no connection and no twist as in a single stroke. However, when the non-connection part becomes extremely long, it is divided into a plurality of pieces having a sufficiently long length in consideration of workability and connected after installation. In the split sufficiently long optical fiber, the above-mentioned connectionless connection is achieved without twist.

Normally, when the optical fiber 13 is wired, a slack portion 35 is formed at a necessary portion of the optical fiber 13 as shown in FIG. 13A, and then the bobbin 34 is attached to the bobbin 34 as shown in FIG. The bobbin 34 may be wound in one direction, or may be wound where necessary while wiring the optical fiber 13.
As shown in FIG. 12 (b), it is wound and fixed by one-way winding, and subsequently, it is wired to a required measuring point, and similarly wound and fixed to the bobbin 34 by one-way winding, as shown in FIG. , A large number of measuring units 33,. However, in this case, the optical fiber 13 is twisted.

Therefore, in the device of the present invention, when a bundle is formed on the optical fiber 13 or the sheath 25 including the optical fiber 13, as shown in FIG. If a bundle is formed on the optical fiber 13 itself or the bobbin 34 by adopting a simple method,
The work can be performed without twisting and without using a special jig. In addition, since portions that are approximately equidistant from the center of the tip of the U-turn portion 35 are wound close to each other, such work is possible. When the bundle is expanded, as shown in FIG.
With the center of the tip of the turn portion 35 as the target center, the aa 'and bb' portions representing the same distance on both sides thereof are set at substantially the same temperature. Then, when the optical fiber 13 is arranged as described above, the measured temperature characteristic with respect to the measurement time has a relationship as shown in FIG. Therefore, when performing data processing using the obtained temperature signal,
If data processing is performed under the relationship of a = a ', b = b',..., n = n ', it is possible to easily correct even if the data fluctuates such as noise. .

That is, a = a ', b = b',..., N =
The relationship of n 'means that they are close to each other, and therefore the physical measurement values should be the same. If they are not the same, the number of measurements is increased and the average For example, the influence of noise can be reduced by increasing the width of the light pulse.

The U-turn section 35 of the optical fiber 13
As shown in FIG. 15, if a material having a heat conductivity different from that of the optical fiber 13 is interposed, or if the heat failure transmission surrounding portion 36 is provided by a material having a different heat conductivity, the start end of the U-turn portion 35 It is possible to form a one-turn bundle while keeping the end close.

Next, FIG. 16 is a diagram showing an improved bobbin. That is, a U-turn groove 34b for hooking the slack portion 35 of the optical fiber 13 is formed in the core 34a of the bobbin 34, and the slack portion 35 of the optical fiber 13 is
By hooking on the turn groove 34b and winding it around the winding core 34a, it is possible to make an optimal U-turn part which does not lose its shape, it is possible to quickly fix the U-turn part, and the winding work on the bobbin can be performed. It is possible to smoothly advance, and it is possible to wind only the slack portion or the required number of times without causing mechanical effects such as twisting.

FIG. 17 is a view showing an example for obtaining the reference position by winding the optical fiber 13 around the bobbin 34. That is, when the required portion of the optical fiber 13 or the sheath 25 including the optical fiber 13 is wound around the bobbin 34, for example, the bobbin 34 is molded with a heat insulating member as shown in FIG. When winding the bobbin 35 around the bobbin 34, the portion wound in the bobbin 34 can be thermally slackened by winding the bobbin 34 while inserting a sheet-like heat insulating member 37 between the layers.

With such a configuration, as shown in FIG. 3B, a temperature slowing portion 38 for position discrimination appears in the temperature characteristic, and the measuring portion of the optical fiber 13 is set with the temperature slowing portion 38 as a reference position. The position of 33 can be known.

FIG. 18 is a view showing another embodiment of the method of winding the slack portion 35 of the optical fiber. In this embodiment, the slack portion 35 of the optical fiber 13 is attached to the core 34a of the bobbin 34.
From the base (root portion), and finally finish the winding at the U-turn 35a, which is the sagging tip, and apply the U-turn portion 35a to the outermost periphery of the bobbin 34 using an adhesive or a string. This is a fixing method. In this case as well, the heat insulating member 37 may be interposed in the same manner as described above. According to this winding method, for example, the temperature at the center of the U-turn tip becomes the same as the temperature of the measured area 32, which can be used to specify a signal indicating the reference position.

Next, FIG. 19 is a view showing a dedicated member for fixing the U-turn portion 35a of the optical fiber 13. In the above embodiment, the U-turn portion 35a at the tip of the slack portion 35 of the optical fiber 13 is hooked on the U-turn groove portion 34b provided on the bobbin 34, but a dedicated fixing having the U-turn groove portion 41a as shown in FIG. A small U-turn portion 35a is formed in the optical fiber 13 by employing the member 41, and the small U-turn portion 35a is formed in the U-turn groove portion 41a of the fixing member 41.
May be attached to the outermost periphery of the bobbin 34 or in the vicinity thereof. With such a configuration, the optical fiber 1
The U-turn portion 35a can be reliably formed in the required portion of No. 3.

FIG. 20 is a diagram showing another example of the structure of the bobbin. This bobbin structure connects two bobbins 34A and 34B having different diameters, and forms bobbins 3 having different diameters.
4A and 34B are wound in a non-inductive manner. Specifically, the base of the slack portion 35 of the optical fiber 13 is wound around a bobbin 34A having a large diameter, while the slack portion 35 is wound.
The U-turn part 34a, which is the tip of the
The small-diameter bobbin 34B is covered with a heat insulating member 37 while being wound around B, thereby obtaining a reference position. Such a bobbin structure is effective when the temperature signal on the slack side corresponding to the large-diameter bobbin 34A is made flat as shown in FIG.

In the above embodiment, the example in which the slack portion 35 of the optical fiber 13 is wound around the bobbin 34 has been described. However, for example, after winding around the winding jig without the bobbin, the jig is removed and the optical fiber 13 is removed. Thirteen winding bundles may be solidified using an adhesive or the like. Next, an embodiment of the invention according to claim 7 will be described with reference to FIGS.

In general, the conventional measuring apparatus forms bundles at predetermined positions of an optical fiber corresponding to each measurement point in a measurement target area, and heats or applies mechanical strain to each bundle one by one. The mechanical distance of each bundle and the distance optically measured by actually entering light are stored in a memory, a memory around a computer, a memory card disk, or the like.

Thereafter, the bundles of the optical fibers are sequentially dispersed and arranged at the respective measurement points in the area to be measured, and then each bundle is heated one by one or subjected to mechanical strain or the like, and light is actually incident. Then, the optical distance of each bundle is read by a thermometer such as an OTDR or the like, and a reference position is obtained by comparing the read distance with a known distance.

On the other hand, according to the apparatus of the present invention, instead of forming a bundle of optical fibers, a required portion of the optical fiber is provided with a color, a character, a numeral, a picture or other code visible from outside, or a magnetic field. After the paint film is applied, the relationship between the mechanical distance to the sign and the like and the optically measured distance is stored in a memory. In this state, depending on the sign or the magnetic sensor, etc., which can be seen from the outside, the bundle of the sign or the magnetic paint film serving as the measuring part of the optical fiber or the part other than the sign or the magnetic paint film is measured. The purpose of the present invention is to realize a OTDR thermometer by making a bundle to be a part.

FIG. 21 shows a specific example. That is, the apparatus of the present invention forms a colored portion 41 of a predetermined length on the optical fiber using a paint or the like so as to correspond to, for example, an equal interval or a measurement point in a measurement area, as shown in FIG. . If the colored portion 41 is colored with black, blue, or the like, the heat absorption efficiency can be improved, which greatly contributes to the improvement of the characteristics as a thermometer.

Thereafter, in the optical fiber 13 having the above-described colored portions 41, the colored portions 41 are bundled as shown in FIG.
Use as The measuring section 42 is optically calibrated in advance. FIG. 22 shows an example in which portions other than the colored portions are bundled.

Next, FIG. 23 is a diagram showing an example in which characters or symbols are provided instead of coloring. In this figure, reference numerals such as coil marks are applied to a required portion of the optical fiber 13 or the sheath 25 of the optical fiber 13 over a distance equivalent to, for example, 1000 mm. Therefore, in this case, a bundle is formed using ± 500 mm around the coil mark.
In addition, according to the display convention, the mark may be a dot or a line.

FIG. 24 is a view in which a magnetic paint is applied on the optical fiber. That is, in this embodiment, a magnetic body 41a such as a magnetic paint or a magnetic tape is applied on the optical fiber 13 instead of the coil mark, and the sheath 25 is covered from above.

According to such a configuration, it is possible to read the magnetic recording portion from the outside of the sheath 25 with a magnetic detector to know the mechanical distance and to form a bundle for forming a measuring section on the optical fiber 13. it can.

When the sheath 25 is made of plastics, if a conductor such as metal vapor deposition or a thin metal tape is applied instead of magnetism, a change in capacitance from the outside of the sheath 25 is detected to reduce the mechanical distance. It is possible to know and to make a bundle in the optical fiber 13. Also, if you apply a dielectric,
High-frequency detection such as microwaves is also possible, and a sign or the like can be detected even if it is slightly away from the sheath 25.

Although the above embodiment has been described on the assumption that the temperature and the temperature distribution are measured, the humidity can be measured in the same manner. In addition, the present invention can be implemented with various modifications without departing from the scope of the invention.

[0078]

As described above, according to the present invention, the following various effects can be obtained.

First, according to the first to fourth aspects of the present invention, a reference other than a measuring part such as an optical fiber and a sheath including the optical fiber is easily covered by merely covering a substance having a different heat transfer coefficient from the optical fiber. It is possible to provide a measuring device which can obtain a position signal and the like and which greatly contributes to improvement of position resolution.

Next, according to the fifth and sixth aspects of the present invention, the detection sensitivity can be increased by forming a bundle at a required portion of the optical fiber, and the bundle can be easily formed without causing twisting of the optical fiber. Therefore, the work of arranging the measuring part of the optical fiber at the measuring point in the measured area becomes easy.

Further, according to the present invention, it is possible to easily obtain known data required for measurement under a certain standard without forming a bundle in an optical fiber before actual use, and furthermore, based on the standard, an optical fiber A bundle can be quickly formed, and the work of arranging the measuring part of the optical fiber at the measuring point in the measured area becomes easy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a measuring device according to the present invention.

FIG. 2 is a time chart for explaining the operation of the measuring apparatus shown in FIG.

FIG. 3 is a configuration diagram showing one embodiment of a signal processing device in the measuring device.

FIG. 4 is a diagram showing an embodiment of a measuring apparatus according to the present invention in which optical fiber measuring sections are arranged in a mesh area in a measurement area.

FIG. 5 is a temperature characteristic diagram when a heat failure transmission surrounding portion is provided in a portion other than the mesh-like measuring portion in FIG. 3;

FIG. 6 is a diagram in which measuring portions of optical fibers are arranged in a mesh shape in an area to be measured in a tank.

FIG. 7 is a diagram in which a thermal failure transmission surrounding portion that represents a reference position by providing a predetermined relationship with a predetermined position of the optical fiber is provided.

FIG. 8 is a diagram in which a hollow thermal failure transmission surrounding portion is provided in an optical fiber.

FIG. 9 forms a bundle at the measuring section of the optical fiber,
The figure which provided the thermal failure transmission surrounding part in required places other than the said measurement part.

FIG. 10 is a diagram in which a bundle is formed in a measurement unit of an optical fiber, and a necessary bundle is provided with a heat failure transmission surrounding unit.

FIG. 11 is a diagram in which a bundle formed in an optical fiber is provided inside a sheath container.

FIG. 12 is a diagram in which a bundle of optical fibers is formed using a bobbin in a measurement target area in a tank, and the bundle is arranged at a measurement point.

FIG. 13 is a view for explaining a conventional general winding method when a bundle is formed in a measuring section of an optical fiber.

FIG. 14 is a diagram illustrating how to wind a bundle of optical fibers according to the present invention.

FIG. 15 is a diagram in which a heat failure transmission surrounding portion is provided at a U-turn portion at the tip of a sag portion of an optical fiber.

FIG. 16 is a diagram showing a bobbin structure in which a U-turn portion at the tip of a slack portion of an optical fiber is easily fixed.

FIG. 17 is a diagram in which a heat insulating member is interposed between layers when a slack portion of an optical fiber is wound around a bobbin.

FIG. 18 is a diagram showing a winding order when a slack portion of an optical fiber is wound around a bobbin.

FIG. 19 is a diagram showing a dedicated fixing member for fixing a U-turn portion at the tip of the slack portion of the optical fiber.

FIG. 20 is a structural view of a bobbin in which two bobbins having different diameters are connected.

FIG. 21 is a diagram in which a required portion of an optical fiber is provided with a code or the like, and then the portion with the code or the like is bundled.

FIG. 22 is a view in which a bundle is formed in a portion other than a sign or the like contrary to FIG. 20;

FIG. 23 is a diagram in which required portions of an optical fiber are provided with coil-shaped reference numerals.

FIG. 24 is a diagram in which a magnetic recording is performed on a required portion of an optical fiber and then a sheath is covered.

FIG. 25 is a configuration diagram for setting a required portion of a conventional optical fiber as a reference position.

FIG. 26 is a configuration diagram for setting a required portion of a conventional optical fiber as a reference position.

[Explanation of symbols]

11 ... light source, 12 ... beam splitter, 13 ... optical fiber, 14 ... signal processing device, 15 ... measured area, 16, 1
6a: Measuring unit, 17, 17a: Thermal failure transmission surrounding unit, 25
... sheath, 25 ... sheath container, 26 ... hollow thermal failure transmission surrounding part, 33 ... measuring part, 34 ... bobbin, 34a ... U-turn groove part, 35 ... slack part, 36 ... thermal failure transmission surrounding part, 3
7: heat insulating member, 41: fixing member, 41a: U-turn groove portion, 41: coloring portion, 42: measuring portion.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01K 11/12 G01N 25/62 G01N 21/65

Claims (7)

(57) [Claims] An optical signal from a light source is incident on an incident end of an optical fiber, and Raman scattering generated in the optical fiber by the incidence of the optical signal until backscattered light returning toward the incident end returns. A measuring device for measuring the temperature, humidity, temperature distribution, or the like of the area to be measured based on the time and the intensity of the returned signal. Alternatively, a material having a different heat transfer coefficient from the optical fiber, the sheath, or the like is directly or directly applied to an appropriate portion other than the measuring portion or to any of the plurality of measuring portions. A heat-transfer heterogeneous substance surrounding portion or a heat-transfer contact portion that is covered in the state of a hollow medium is provided, and a material having a different heat transfer from the measuring portion generated when a temperature variation or a temperature change of the measured portion is given. Measuring device characterized by obtaining the reference position signal by utilizing a temperature difference between the measurement portion of the covered portion at. 2. The measuring apparatus according to claim 1, wherein the heat-defective transmission surrounding portion, which is a heat-transfer heterogeneous substance, uses a heat-defective transmitter such as plastics or heat insulating material. 3. The heat-transfer enclosing portion or heat-transfer contact portion, which is a heat-transfer heterogeneous substance, includes a radiating fin, a cold / hot body (a cooling pipe through which cooling water passes, a structure connected to a low-temperature portion, and the like). The measuring apparatus according to claim 1, wherein a heat transfer medium such as a heat transfer medium is used. 4. The heat-failure-transmitting enclosure includes a reference position signal having a predetermined specific meaning by changing a length of the heat-failure-transmitting enclosure or an interval between a plurality of adjacent heat-failure-transmitting enclosures. The measuring device according to claim 1, wherein 5. An optical signal from a light source is incident on an input end of an optical fiber, and Raman scattering generated from within the optical fiber by the input of the optical signal until back-scattered light returning toward the incident end returns. In the measuring device for measuring the temperature, humidity, temperature distribution, etc. of the measurement target area based on the time of and the intensity of the returned signal, a slack portion is provided at a required portion of the optical fiber or a sheath containing the optical fiber. formed, wound using a plurality of bundles or bobbins wound at least one turn or more wound with Sowase to substantially close the equidistant portions each other from the center of the U-turn portion of the optical fiber which is the slack tip Duplicate
Among the measurement portion of the number of bundles, the light-off in the measurement portion of the responsibility number number of bundles
Fiber, heat covered with a material having a different heat transfer coefficient from the sheath
Provide a fault transmission surrounding part, and change the temperature or temperature of the part to be measured.
Of the measurement unit and the heat transfer coefficient generated when a change is given
Use the temperature difference between the measurement part and the part covered with a different substance.
Measuring device being characterized in that to obtain a reference position signal Te. 6. The bobbin has a U-shaped optical fiber around the bobbin core.
Turn groove is formed, the U data and the U-turn portion to form the sheath interior of the optical fiber or optical fiber
6. The measuring device according to claim 5, wherein the measuring device can be hooked on the groove . 7. An optical signal from a light source is incident on an incident end of an optical fiber, and Raman scattering generated in the optical fiber by the incidence of the optical signal until backscattered light returning toward the incident end returns. A measuring device for measuring the temperature, humidity, temperature distribution, or the like of the measurement target area based on the time of the measurement and the intensity of the returned signal. Color, letters, numbers, pictures, and other codes or magnetic paint films for measuring the optical distance and optical position, and applying the codes or magnetic paint films after performing the mechanical distance and optical position measurements. Of the measuring units of a plurality of bundles having a predetermined number of turns as a guide,
In the measuring part, the optical fiber and the sheath
Provide a thermal failure transmission surrounding area covered with a different substance, and
The measurement that occurs when a temperature change or a temperature change is given
Part and the measurement part of the part covered with the substance having a different heat transfer coefficient.
This <br/> a measuring device, characterized in that to obtain the reference position signal by utilizing a temperature difference between.