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WO2014083931A1 - Manomètre à fibre optique - Google Patents

Manomètre à fibre optique Download PDF

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Publication number
WO2014083931A1
WO2014083931A1 PCT/JP2013/076523 JP2013076523W WO2014083931A1 WO 2014083931 A1 WO2014083931 A1 WO 2014083931A1 JP 2013076523 W JP2013076523 W JP 2013076523W WO 2014083931 A1 WO2014083931 A1 WO 2014083931A1
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WO
WIPO (PCT)
Prior art keywords
optical fiber
pressure
cylindrical body
temperature
strain
Prior art date
Application number
PCT/JP2013/076523
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English (en)
Japanese (ja)
Inventor
欣増 岸田
Original Assignee
ニューブレクス株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ニューブレクス株式会社 filed Critical ニューブレクス株式会社
Priority to JP2014550072A priority Critical patent/JPWO2014083931A1/ja
Publication of WO2014083931A1 publication Critical patent/WO2014083931A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/0026—Transmitting or indicating the displacement of flexible, deformable tubes by electric, electromechanical, magnetic or electromagnetic means
    • G01L9/0032—Transmitting or indicating the displacement of flexible, deformable tubes by electric, electromechanical, magnetic or electromagnetic means using photoelectric means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
    • G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
    • G01L11/025—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means using a pressure-sensitive optical fibre

Definitions

  • the present invention relates to an optical fiber pressure gauge that measures the pressure of a liquid by obtaining deformation due to liquid pressure generated in a cylindrical structure installed in the liquid from a physical quantity detected by an optical fiber attached to the structure. It is about.
  • the method of converting the liquid pressure to a liquid level by measuring the pressure of the liquid with a sensor or the like is the most common method. It is adopted as one.
  • an electrical type obtained from an electrical signal output from the electronic component by liquid pressure using an electronic component such as a piezoelectric element installed in the liquid, or a point type optical fiber There is known a method that uses a type of FBG (Fiber Bragg Grating) optical fiber.
  • FBG Field Bragg Grating
  • an electronic component such as a semiconductor, a resistor, a capacitor, or the like is used, a voltage is applied to the electronic component to operate, and a voltage / current is output as a sensor output.
  • An example of a water level meter using the FBG method is to measure the water level by converting the water pressure change due to the water level change during a flood into an FBG expansion / contraction using a mechanical method using a ring spring (see Non-Patent Documents 1 and 2). ) Or a reflection type optical fiber water level meter that converts the pressure change of the water level into an optical signal with the FBG of the optical strain gauge.
  • the measuring range is 10 m, the accuracy is ⁇ 1%, and the measuring distance is a maximum of 15 km.
  • a measurement point only one point can be measured in principle, and when performing multi-point measurement, the number of measuring devices is required.
  • a method of measuring a water pressure or a liquid pressure at a measurement point and converting it to a water level or a liquid level is often used.
  • temperature correction it is necessary to perform this temperature correction, and in particular, there is a temporal temperature change. If it is large, it is difficult to accurately compensate for the influence of temperature from the measurement result.
  • the electric type it is not possible to measure both pressure and temperature at the same time with one measuring instrument, and separately from pressure measurement, the water temperature or liquid temperature at the time of pressure measurement is measured with another measuring instrument and the effect Must be compensated.
  • measurement is performed using the fact that the reflection wavelength of the FGB changes according to the strain applied to the optical fiber and the temperature change. This wavelength change is caused by strain and temperature change. Therefore, when the reflection wavelength changes, it is difficult to evaluate the influence of both of them completely and independently with only one optical fiber, and at least two FBGs are required. Another measure is required, for example, one of the FBGs must be used for temperature compensation.
  • the measurement range of the FBG method is about 10 m at maximum in terms of the water level as described above. For example, it cannot be used for measuring a water level exceeding 10 m or pressure of an oil well having a depth of several hundred meters. Is possible. Also, the measurement accuracy does not reach 0.007 MPa with the conventional measuring instrument.
  • the present invention has been made in view of the above problems, and by measuring simultaneously the strain and temperature generated in the optical fiber attached to the cylindrical body, the strain of the cylindrical body deformed by the hydraulic pressure, An object of the present invention is to provide an optical fiber pressure gauge capable of measuring pressure accurately.
  • the optical fiber pressure gauge of the present invention is A cylindrical body that is installed in a liquid or gas and deforms due to pressure and temperature, is wound in close contact with the outer periphery of the cylindrical body, and deforms when the cylindrical body is deformed to deform the cylindrical body.
  • a sensor having a first optical fiber for detecting strain and temperature; A pulse laser beam is emitted to the first optical fiber, and a change in the frequency of Brillouin scattering and a change in the frequency of Rayleigh scattering are detected from the scattered light generated in the optical fiber.
  • Brillouin scattering / Rayleigh scattering hybrid backscatter measuring machine that detects body strain and temperature separately, A second optical fiber that transmits the emitted pulsed laser light or the scattered light; From the change in the detected Brillouin scattering frequency and the change in the Rayleigh scattering frequency, the strain change and temperature change of the cylindrical body are calculated, and the strain change and temperature change obtained by the calculation are calculated. And an arithmetic device that calculates and calculates the pressure of the liquid or gas at the position where the cylindrical body is installed.
  • Example 1 to which the measuring apparatus by Embodiment 1 of this invention is applied. It is a figure which shows the measurement flow of the measuring apparatus of the said Example 1.
  • FIG. It is a figure which shows Example 2 to which the measuring apparatus by Embodiment 1 of this invention is applied. It is a figure which shows Example 3 to which the measuring apparatus by Embodiment 1 of this invention is applied. It is a figure which shows the example of another measuring apparatus by Embodiment 1 of this invention.
  • FIG. 1 is a diagram showing an overall configuration of an optical fiber pressure gauge according to Embodiment 1 of the present invention.
  • an optical fiber pressure gauge is a Brillouin scattering / Rayleigh scattering hybrid backscattering measuring instrument 1 (hereinafter abbreviated as an R & B hybrid backscattering measuring instrument) for measuring frequency changes of both Brillouin scattering and Rayleigh scattering.
  • the optical fiber 2 connected to the R & B hybrid backscattering measuring instrument 1 and serving as an optical transmission line (hereinafter, the optical fiber as the optical transmission line is also referred to as a second optical fiber).
  • a sensor 3 for detecting strain and temperature using an optical fiber different from the optical fiber 2 (hereinafter, this optical fiber for detecting strain and temperature is referred to as a first optical fiber), and an R & B hybrid type.
  • Distortion change caused in the first optical fiber from the frequency change of both Brillouin scattering and Rayleigh scattering detected by the backscattering measuring machine 1 together with the determined by calculating the temperature change, the arithmetic unit 4 in which the sensor 3 to calculate the pressure of the installed liquid or gas, is composed of four basic elements.
  • the R & B hybrid backscatter measuring instrument 1 uses the phenomenon that the frequency of Rayleigh and Brillouin scattered backscattered light varies depending on the strain and temperature generated in the first optical fiber constituting the sensor 3.
  • the sensor can be basically composed of one as shown in FIG. 1a), but as shown in FIG. 1b), the sensor has different physical characteristics.
  • the sensor is composed of two (for example, in the case of measuring the pressure of volatile gas and liquid simultaneously in a volatile liquid storage. Details will be described later. Do).
  • the distinction between the first optical fiber and the second optical fiber is a functional distinction, and the same fiber may be used.
  • additional sensors, optical fibers, and the like are additionally connected.
  • the measurement principle of the R & B hybrid backscattering measuring instrument 1 will be further described here.
  • the Brillouin scattering used in this measuring device is the basic that the scattered light scattered inside the optical fiber generates ultrasonic waves using the pulsed laser light incident on the optical fiber, and the ultrasonic waves generate scattered light.
  • the principle is used, but the PPP-BOTDA (Pulse-PrePump Brilloun Optical Time Domain Analysis) method is adopted to further improve the measurement accuracy.
  • Rayleigh scattering is based on the basic principle that density fluctuations in glass materials generate scattered light.
  • TW variable wavelength
  • COTDR Tunable Wavelength Coherent Optical Time Domain Reflectometry
  • the R & B hybrid type backscattering measuring instrument 1 which is a constituent element of the present invention, uses these two scattered lights at the same time, and changes in the order of MHz due to temperature and strain changes in the optical fiber axis direction obtained by the above-mentioned sensor or the like.
  • the temperature and strain information can be separated and extracted from the information of the Brillouin scattering frequency and the Rayleigh scattering frequency changed in the GHz order (both contain information on both strain and temperature change).
  • the R & B hybrid backscattering measuring instrument 1 is a Brillouin scattering and Rayleigh scattering hybrid backscattering measuring apparatus capable of acquiring highly accurate information on strain and temperature change independently from one optical fiber at the same time.
  • FIG. 2 is a cross-sectional model diagram showing the detailed structure of the sensor 3.
  • a cylindrical body 5 is arranged in the central portion, a pressure p is applied to the inner periphery thereof by a liquid, and a detection of a circumferential strain sensor generated in the cylindrical body by the pressure p is applied to the outer periphery.
  • the portion 6 is spirally wound about several tens of times in close contact with the outer peripheral portion of the cylindrical body.
  • O-rings 7 are disposed on the outer circumferences of the left and right ends of the cylindrical body, and a casing 8 is disposed in a form that covers the cylindrical body 5 from the outside via the O-ring 7.
  • the O-ring 7 has a function of preventing liquid from entering the initial pressure holding space (indicated as Q in FIG. 2) formed between the cylindrical body 5 and the housing 8. By this initial pressure holding space, the influence of pressure from the outside of the sensor is blocked.
  • the two right and left optical fibers (shown by dotted lines) connected to the optical fiber of the detection unit 6 wound around the cylindrical body 5 are not constituent elements of the sensor 3 and correspond to the optical fiber 2 described above. To do.
  • FIG. 4 is a cross-sectional model view of a cylindrical body.
  • the cylindrical body has an outer diameter D and a wall thickness ⁇ .
  • the hoop stress ⁇ h and the hoop strain ⁇ h generated in the tubular body when the pressure p is applied to the inside of the tubular body are expressed by the following equations (1), Determined in (2).
  • the cylindrical body is deformed not only by pressure but also usually by temperature. In the following formulas (1) and (2), it is assumed that this influence is small. When deformation due to temperature cannot be ignored, calibration is performed in advance before actual measurement, and the deviation from the value of ⁇ h or ⁇ h obtained from Equation (1) or Equation (2) is corrected. Evaluate.
  • the liquid flows into the space inside the cylindrical body, and the pressure of the liquid generated in this portion is the inner circumference of the cylindrical body.
  • the strain generated on the outer peripheral surface of the cylindrical body when acting as a load (internal pressure) on the surface is measured with an optical fiber.
  • an optical fiber is tightly wound around and attached to the outer periphery of the cylindrical body, and an initial pressure holding space is provided on the outer periphery of the cylindrical body to block a load (external pressure) from the outside of the sensor.
  • the sensor is configured to be formed in a cylindrical shape between the outer peripheral portion of the cylindrical body and the housing 8.
  • the optical fiber By attaching the optical fiber to the cylindrical body in this way, the strain caused by the deformation of the cylindrical body in the radial direction perpendicular to the axis of the cylindrical body is reduced by the internal pressure due to the liquid loaded on the cylindrical body. It can be grasped as an axial strain.
  • the optical fiber in order to increase the strain sensitivity, is wound in multiple layers on the outer periphery of the cylindrical body (see FIG. 3).
  • the cylindrical body used has a relatively large amount of strain, that is, a material with a larger deformation than ferrous metals and excellent durability (fatigue strength, chemical resistance, etc.). It is preferable to do.
  • the strain and temperature coefficient D 11 of the frequency of the Brillouin scattering is a characteristic value of the optical fiber itself, the frequency of the Rayleigh scattering by using a strain and coefficient of temperature D 12 of the formula (3).
  • ⁇ is the amount of change in strain of the optical fiber in the sensor
  • ⁇ T is the amount of change in temperature
  • ⁇ B is the amount of change in Brillouin frequency
  • ⁇ R is the amount of change in Rayleigh frequency
  • D 11 and D 21 are strains of Brillouin frequency.
  • Temperature coefficients D 12 and D 22 are Rayleigh frequency distortion and temperature coefficients.
  • the strain can be calculated from the equation (3).
  • the amount of change and the amount of temperature change can be known.
  • FIGS. 6 and 7 show actual measurement examples when the water level is measured using the pressure gauge according to the present invention.
  • FIG. 6 is an actual measurement example of the Rayleigh frequency change when the water pressure changes due to the depth change when the measurement position of the pressure gauge is changed and the water depth is measured in the range of 25 m to 26 m.
  • the horizontal axis represents the measurement position on the optical fiber in units of m, and a portion 60 cm from the position of about 25 m corresponds to the sensor 3 portion.
  • this figure shows data measured up to a water depth of 35 cm in 10 cm steps with a water depth of 5 cm as an initial value (initial depth).
  • FIG. 6 is an actual measurement example of the Rayleigh frequency change when the water pressure changes due to the depth change when the measurement position of the pressure gauge is changed and the water depth is measured in the range of 25 m to 26 m.
  • the horizontal axis represents the measurement position on the optical fiber in units of m, and a portion 60 cm from the position of about 25 m corresponds to the
  • FIG. 7 shows the value of the water depth and the amount of change in the Rayleigh frequency with reference to the value at a water depth of 5 cm based on FIG. 6, and corresponds to the sensitivity characteristic. It can be seen that the relationship between the Rayleigh frequency change value and the measurement position change amount is not completely linear, but has a sensitivity of 5 cm.
  • the characteristic coefficient of the optical fiber (strain and temperature coefficients D 11 , D 21 , D 12 , D 22 in the above equation (3)) is obtained by a preliminary experiment.
  • an initial measurement such as a temperature-controlled room at a temperature T 0
  • an initial strain ⁇ 0 of the optical fiber and a reference spectrum of Rayleigh scattering and Brillouin scattering (for example, relational data of measurement position and scattered light level) are obtained.
  • install the sensor at the position to be measured, measure the spectrum of Rayleigh scattering and Brillouin scattering when hydraulic pressure is applied at that position, analyze it against the previous reference spectrum, and analyze Rayleigh scattering and Brillouin.
  • ⁇ and ⁇ T are obtained by substituting the obtained frequency change value and the characteristic coefficient of the fiber into Equation (3). Thereafter, ⁇ 0 and T 0 obtained in the initial measurement are used to obtain ⁇ and T at the measurement position. Then, the characteristic value (D, ⁇ , E) of the cylindrical body is read from a memory (not shown) with ⁇ determined here as ⁇ h , and the pressure p at the measurement position is calculated using the equation (2).
  • ⁇ the characteristic value (D, ⁇ , E) of the cylindrical body is read from a memory (not shown) with ⁇ determined here as ⁇ h , and the pressure p at the measurement position is calculated using the equation (2).
  • the processing unit 4 and subsequent steps for obtaining ⁇ and ⁇ T are executed.
  • the optical fiber when used as the sensor as described above, it is necessary to wind around the cylindrical body as shown in FIGS. 2 and 3. For this purpose, it is necessary to bend the optical fiber. is there.
  • the conventional optical fiber uses quartz-based glass as the material, so light leakage inside the optical fiber is likely to occur, and light can be emitted even if the optical fiber is bent slightly. Leakage transmission quality decreases. Therefore, it has been difficult to bend at a certain angle or more.
  • the sensor when the sensor must be downsized (the outer diameter of the cylindrical body is 20 mm or less), that is, when the outer diameter of the cylindrical body must be reduced, the degree of bending is large (minimum optical fiber). Therefore, it is difficult to use a conventional ordinary fiber as it is.
  • a holey fiber is used for the detection unit 6 because it is necessary to downsize the sensor 3.
  • the holey fiber is an optical fiber having a structure in which a center line serving as an optical waveguide is surrounded by a plurality of holes (holes) (see FIG. 9).
  • a plurality of holes 10 provided in the clad 11 surround the core 9.
  • the biggest feature of this holey fiber is that it is strong against bending of the wire. With holey fibers, transmission quality does not deteriorate even if the bending is slightly increased by increasing the difference in refractive index between the cladding and the core (commercially available products have a 5mm minimum bend radius of 1/6 the usual).
  • air holes are provided in the cladding to improve the light reflectivity by utilizing the fact that the refractive index of air is lower than that of the cladding, so that the difference in refractive index between the cladding and the core can be substantially increased.
  • the minimum bending radius can be set smaller than usual.
  • the example shown in FIG. 10 can be proposed as a specification example of the optical fiber pressure gauge that realizes the present invention.
  • the main specifications are that the maximum installation depth is 600 m, the measurement range is 0-6 MPa, and the measurement accuracy is 5 cm.
  • the temperature and strain of the optical fiber attached to the cylindrical body placed in the liquid can be measured using the Brillouin scattering / Rayleigh scattering hybrid backscattering measuring machine.
  • the deformation of the cylindrical body can be measured, and the pressure of the liquid can be measured in a wider measurement range than before (measurable to a larger depth range) and can be measured accurately. An effect can be obtained.
  • an increase in measurement distance (about 100 km or more) will be described with reference to FIG.
  • two-way optical amplifiers 12 are provided at a rate of one per 80 km of the minimum distance on the far side of the sensor 3 as viewed from the R & B hybrid backscattering measuring machine 1. .
  • Example 1 an example using the above optical fiber pressure gauge will be described first with reference to FIG. 12 (Example 1).
  • the pressure and temperature of the liquid in the tank 13 storing the volatile liquid and the gas (in the gas layer above the liquid in the tank) are measured using the two sensors of the present invention. It is possible to monitor the liquid level (liquid level) of the liquid stored in the tank and to monitor the fuel component in the upper gas layer (specification of the type of fuel). The details will be described below.
  • the senor uses two sensors, a sensor 3a placed in a gas layer and a sensor 3b placed in a liquid.
  • the distance from the tank bottom surface of the sensor 3b is H 0 and the liquid level of the liquid is H from the tank bottom surface
  • the tank internal pressure because the volatile liquid is volatilized, the pressure p 1 is generated.
  • the sensor 3a not only the pressure p 1 of the gas layer, it is possible to measure temperature (to T 1) at the same time of the gas layer, the vapor pressure at a temperature T 1 of the p 1 as the vapor pressure of the gas in the gas layer From this, it is considered that the type of gas in this gas layer can be specified. That is, according to the Antoine equation, which is an empirical formula related to the vapor pressure, the following equation (4) is established when the vapor pressure p and the temperature T are used.
  • A, B, and C are constants that depend on substances, vapor pressure, and temperature units (Antoine constants).
  • the liquid level H can be determined according to the procedure shown in FIG. That is, among the positions where the sensors are installed, the position H 0 where the sensor 3b is installed and the pressure and temperature measured by the two sensors 3a and 3b are stored in a memory (not shown), and the pressure p 1 detected by the sensor 3a. , Temperature T 1 , density ⁇ of various substances, and characteristic values related to the above-mentioned Antoine A, B, and C (not shown.
  • the number n related to the type of substance j is the liquid level
  • the maximum number of substances handled by the person to be monitored) using the values of A, B and C specified assuming a certain substance and the density ⁇ (value at temperature T 1 ) of the certain substance (4) is calculated.
  • the calculation is stopped, and the liquid level is determined using the density ⁇ of the substance at the temperature T 2 determined at that time.
  • H the liquid level of the liquid in the tank is monitored.
  • j is performed up to the maximum number n, and if the values of the left side and the right side of Equation (4) are equal to or less than a predetermined value, it is considered that Equation (4) is satisfied.
  • the stored substance is known in advance, if the measured values p 1 and T 1 do not satisfy the Antoine equation, it is expected that impurities other than the stored substance exist in the tank. That is, it is possible to monitor over a long period whether or not the purity of the stored substance is maintained.
  • the sensor of the present invention is used for measuring the water level of a water-soluble gas well, that is, a natural gas well dissolved in water.
  • a water-soluble gas well that is, a natural gas well dissolved in water.
  • the water level of the casing 16 which is the water level of the water-soluble gas well (symbol W in the figure) was installed in the outer blowing pipe 17a which is an observation well (symbol U in the figure) connected to the casing.
  • Monitoring is performed with a measured water head (water level) Hm indicated by an arrow in the outer blowing pipe measured by the sensor 3.
  • natural gas flows from the strainer 18.
  • the gas lift from the outer blowing pipe 17b is used to increase the flow rate of the liquid in the water-soluble gas well.
  • Information of the sensor is transmitted to a station which is a pumping station through a pipeline used for liquid transportation or the like by an optical fiber 2.
  • the station in addition to the R & B hybrid type backscatter measuring instrument 1, the station includes a plurality of optical fibers (not shown) that are detected by a casing, a liquid observation well, or an optical fiber (not shown) used for sensing.
  • a facility (server) that collects information and manages them collectively is provided, and the deformation, life, etc. of the casing, the observation well of the liquid or the pipeline can be monitored.
  • this station is usually equipped with a power source, it is possible to send the information to the information center by wire or wirelessly, so that the water level and liquid level can be monitored remotely.
  • the observation well can be observed with an accuracy of 5 cm up to a depth of several hundred meters.
  • an optical fiber is buried along the gas pipe, it is possible to measure the temperature distribution of the gas pipe and monitor the pipeline (pressure and temperature measurement).
  • This example is an example of monitoring the sea level height or tsunami with the sensor of the present invention.
  • a long distance such that the distance is 100 km or more in a plurality of locations with different depths and in a planar distance measurement range is defined as a measurement target.
  • the water level of the seawater is monitored.
  • monitoring the change in height is considered to be the most important, so measuring the change in water level is essential.
  • the magnitude of the tsunami is determined through the station 14, and the alarm system is notified as necessary.
  • FIG. 16 is a diagram showing an example of another measuring apparatus according to Embodiment 1 of the present invention.
  • an optical switch 19 is further added between the optical fiber and the sensor. According to this apparatus, in addition to the above effect, by switching the optical switch 19, it is possible to measure different measurement objects at a desired timing and time. About effects other than these, it is the same as that of the above-mentioned description.
  • FIG. 17 is an explanatory diagram of a measuring apparatus according to Embodiment 2 of the present invention.
  • the sensor is arranged inside the casing or inside the outer blowing pipe to measure the liquid pressure or the like at that position.
  • the second embodiment is applied to a case where a sensor is arranged outside the casing to measure the external pressure of the casing for monitoring the casing and evaluating the life. This is an example. This will be described below with reference to FIG.
  • a position which is the measurement target that shown by a double-headed arrow indicates the depth (reference symbol L D in the figure).
  • external pressure a sensor 20 having a form different from that of the first embodiment is installed at the position of the target depth to be evaluated. Is done.
  • the sensor 20 is an optical fiber having a sensor function (detecting unit 6), a cylindrical optical fiber mounting cylinder 21 to which the optical fiber of the detecting unit 6 is mounted, and an optical fiber mounting by directly receiving the external pressure on the outer periphery of the casing 16.
  • An external pressure transmission medium 22 that transmits external pressure to the cylinder 21 is configured.
  • an initial pressure holding space (indicated as Q) in the figure is formed between the optical fiber mounting cylinder 21 and the casing 16, and the internal pressure of the casing is cut off to measure the internal pressure.
  • the optical fiber mounting cylinder 21 is made of a material that is not deformed only at a position where it is in contact with the external pressure transmission medium 22 and is deformed on average over the entire depth direction.
  • the strain and temperature information of the sensor 20 is transmitted to the station 14 through the optical fiber 2 which is a transmission line connected to the sensor 20 and through the pipeline 15 used for liquid transportation.
  • the station 14 is equipped with equipment (servers) that can collect information from a plurality of sensors and collectively manage the information.
  • the casing, the liquid observation well, or the pipeline can be monitored in the same manner as described above.
  • the station since the station is usually equipped with a power supply, it is possible to send the information to the information center by wire or wirelessly, so that it is possible to monitor the external pressure remotely.
  • the optical fiber can be buried along the gas pipe, it is possible to measure the temperature distribution of the gas pipe and monitor the pipeline (pressure and temperature measurement).
  • the optical fiber type pressure gauge of the present invention even with a liquid having a temperature distribution or a strain distribution, the measurement of the pressure of the liquid to be measured can be performed with only one sensor. Since it is possible to carry out with high accuracy in the range, water level can be monitored accurately. In addition, if an optical amplifier is connected, it is possible to monitor a wide range of pipelines and the like and have a wide application range.
  • the optical fiber pressure gauge of the present invention can be used as a soil pressure gauge.
  • a resistance wire strain gauge is attached to a leaf spring that is the pressure receiving surface, and the displacement of the pressure receiving surface is measured to measure the strain of the resistance wire strain gauge, thereby measuring the earth pressure at the dam construction site. There was something to do.
  • FIG. 18 is an explanatory diagram showing an example of the configuration of a measuring apparatus when the optical fiber pressure gauge of the present invention is used for a soil pressure gauge.
  • the figure shown in the lower part of this figure (FIG. 18 (b)) is an explanatory view of the actual use situation, and the figure in the upper part (FIG. 18 (a)) shows the present measuring apparatus with the earth and sand removed. It is a figure which shows an internal structure at the time of seeing from an upper surface.
  • oil 33 which is a pressure transmission body is enclosed in a cylinder 32 in advance.
  • the pressure of the earth and sand 36 on the diaphragm 34 is transmitted to the oil 33, and the earth pressure is measured by the optical fiber 2.
  • a signal generated by earth pressure is transmitted to the outside by the optical fiber 2 through the optical fiber connection portion 35 installed outside the outer shell 31 of the diaphragm 34, and the optical fiber pressure gauge installed outside the The pressure is measured.
  • 1 Brillouin scattering / Rayleigh scattering hybrid backscattering measuring machine (R & B hybrid backscattering measuring machine), 2 optical fiber, 3, 3a, 3b, 20 sensor, 4 arithmetic unit, 5 cylindrical body, 6 detector, 7 O-ring, 8 housing, 9 core, 10 holes, 11 cladding, 12 two-way optical amplifier, 13 tanks, 14 stations, 15 pipelines, 16 casing, 17, 17a, 17b outer blow pipe, 18 Strainer, 19 Optical switch, 21 Optical fiber mounting cylinder, 22 External pressure transmission medium.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Measuring Fluid Pressure (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)

Abstract

La présente invention concerne une seule fibre optique qui est enroulée et fixée sur la circonférence extérieure d'un corps cylindrique et qui détecte la température et la contrainte dans le corps cylindrique déformé par la pression d'un liquide, la pression du liquide étant déterminée à partir de la contrainte dans le corps cylindrique générée par la pression du liquide par détection des modifications à la fois dans la fréquence de diffusion de Brillouin et dans la fréquence de diffusion de Rayleigh pour la lumière diffusée dans la fibre optique et ainsi séparation et détection simultanée de la température et de la contrainte dans le corps cylindrique.
PCT/JP2013/076523 2012-11-30 2013-09-30 Manomètre à fibre optique WO2014083931A1 (fr)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017032126A (ja) * 2015-08-06 2017-02-09 ホーチキ株式会社 水素ステーションの防災設備
CN109163829A (zh) * 2018-09-17 2019-01-08 哈尔滨工业大学 基于布里渊和瑞利双机制的高性能动态分布式光纤传感器
JPWO2021075145A1 (fr) * 2019-10-18 2021-04-22
CN113916323A (zh) * 2021-09-10 2022-01-11 深圳伊讯科技有限公司 储油罐光纤液位智能监测系统

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CN113916323A (zh) * 2021-09-10 2022-01-11 深圳伊讯科技有限公司 储油罐光纤液位智能监测系统

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