JP4823087B2 - In-leak flow measuring device - Google Patents

Description

The present invention relates to equipment for measuring the leakage flow rate in the pipe system.

  Conventionally, a detection device that detects a leak in a piping system uses a sensor that is normally used during operation monitoring. That is, a leak is detected and a location where the leak occurs is determined using a measured value from an operation monitoring sensor provided in a piping system to be detected.

As an example of such a leak detection apparatus, a pipe leak monitoring apparatus that detects the occurrence of leak by combining a flow sensor and a vibration sensor as shown in Patent Document 1 is known.
JP 2004-138627 A

  However, since the leak detection device of the piping system as shown in Patent Document 1 detects a leak by a sensor used for normal monitoring, the number of sensors is small, and it is difficult to specify a leak occurrence location. In particular, if an internal leak occurs due to a valve failure, misoperation, pinhole, etc. in a piping system that should not flow, such as a system that is isolated from the plant or in a standby state, the leak flow rate is very small. For this reason, there is a problem that measurement itself is difficult with a sensor used for normal monitoring.

Accordingly, the present invention aims at providing a equipment that can easily measure the slight Inriku in the pipe system.

In order to achieve the above object, an inflow flow measuring device according to the present invention includes a heater that is provided outside a pipe to be measured and heats a part of the length of the pipe, and a portion heated by the heater. a temperature measuring means, respectively in the longitudinal direction on both sides of the pipe provided with a plurality of measuring pipe surface temperature of, calculating means for calculating the temperature distribution of the pipe length direction from the measured values measured by the temperature measuring means of these When the reference data storage means is stored in advance the relationship between the pipe flow rate and the calculated temperature distribution by the computing means, and a temperature distribution calculated by said calculating means is stored in advance in the reference data storage means And determining means for determining the flow rate in the pipe by comparing the temperature distribution in the length direction .

  According to the present invention, a slight in-leak in the piping system can be easily measured.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 1 is a schematic view showing a basic configuration of a first embodiment of an inleak flow measuring device according to the present invention. In FIG. 1, a heater 2 for heating the pipe 1 is disposed on the outer circumference of the pipe 1 to be measured, and a heating amount control device 3 for adjusting the heating amount of the heater 2 is provided. . The heater 2 has a predetermined length in the length direction (axial direction) of the pipe 1 and has a ring shape that is disposed on the outer periphery of the pipe 1.

  Thermocouple thermometers 4a to 4f, which are temperature measuring means for measuring the temperature of the pipe surface, are arranged at equal intervals at positions A to F in the length direction of the pipe 1 on both sides of the heater 2. Furthermore, the data input device 5 for inputting the measurement data from the thermocouple thermometers 4a to 4f, the data recording device 6 for recording the measurement data from the data input device 5, and the temperature of the measurement data recorded in the data recording device 6 An arithmetic device 7 for calculating the distribution bias is provided. Further, the deviation of the temperature distribution based on the measurement data from the arithmetic unit 7 is input, and the direction of the leak and the flow rate are determined by comparing the relationship between the leak flow rate stored in the reference data storage device 8 and the deviation of the temperature distribution. And a display device 10 for displaying a result of the comparison determination device 9.

  Here, the piping 1 is a piping system in which there is no normal flow, or a piping system in which the upstream side and the downstream side are closed by a valve or the like at the time of measurement, and a flow rate due to a small amount of leakage is generated in the direction of the arrow in the figure. .

  The effect | action by the inleak flow measuring apparatus of the above structures is demonstrated. When the surface of the pipe 1 is heated by the heater 2, the temperature of the fluid inside the pipe 1 also rises due to heat conduction. Here, when there is a flow due to leakage inside the pipe 1, the warmed fluid moves downstream (in the direction of the leakage occurrence location, that is, in the direction of the arrow in the figure). As a result, the inner wall temperature of the pipe 1 on the downstream side (D, E, and F positions in the figure) rises and becomes higher than the inner wall temperature on the upstream side (positions A, B, and C in the figure).

  An example of measurement data by the thermocouple thermometers 4a to 4f at this time is shown in FIG. In FIG. 2, the center vertical line is the heater 2 position, and the temperatures of the pipe surfaces at the upstream measurement positions A, B, C and the downstream measurement positions D, E, F are shown.

  Here, if there is no leak, the heat conduction from the heater 2 is uniform, so that the measurement positions A and F, B and E, and C and D having the same distance from the heater 2 have the same temperature, and the measurement in FIG. The data should be symmetric on the upstream and downstream sides of the heater 2. On the other hand, if a leak occurs as shown in FIG. 1, the piping at the measurement positions F, E, and D on the downstream side at the measurement positions A and F, B and E, and C and D as shown in FIG. The surface temperature becomes higher than the corresponding upstream measurement positions A, B, and C, and the temperature distribution becomes asymmetrical in the upstream and downstream of the heater position, resulting in uneven distribution.

  Signals from these thermocouple thermometers 4 a to 4 f are input to the data input device 5, and are taken into the data recording device 6 through the measurement data input device 5. The arithmetic device 7 sequentially calculates the degree of bias of the temperature distribution from the measurement data recorded in the data recording device 6. FIG. 3 shows an example of the temporal change in the calculation result of the degree of bias of the temperature distribution at this time. The degree of deviation of the temperature distribution is obtained, for example, as the position of the center of gravity of the temperature distribution, the measurement position indicating the maximum temperature obtained by approximating the temperature distribution with an arbitrary function, or the area difference or ratio of the temperature distribution before and after the heater. Can do.

  In the reference data storage device 8, reference data indicating the relationship between the degree of deviation of the temperature distribution and the flow rate as shown in FIG. 4 is stored in advance. The comparison / determination unit 9 determines the flow direction inside the pipe according to which direction the heating distribution starts after the start of heating based on the degree of deviation of the temperature distribution calculated by the arithmetic unit 7. Further, a comparison is made between the degree of deviation after the elapse of a certain time after heating or the relationship between the deviation degree of the distribution stored in the reference data storage device 8 and the flow rate based on the change rate of the deviation degree, etc. Ask for.

  Since thermocouple thermometers 4a to 4f have measurement errors, there may be a deviation in temperature distribution even when there is no flow due to leakage. For this reason, the difference of each temperature measurement value before heating the heater 2 is recorded in the data recording device 6, and the measurement error of the thermometer is corrected by correcting the temperature measurement value measured after the heater 2 heating.

  As described above, according to the present embodiment, the heater 2 and the thermocouple thermometer 4 are arranged at an arbitrary position of the pipe 1, and the leak direction and the leak flow rate can be measured from the degree of bias of the temperature distribution due to heating. it can. Furthermore, it is particularly useful for measuring in-leakage in a standby system with no normal flow rate or a piping system that is not monitored, such as a piping system in a large-scale plant such as a nuclear power plant.

[Second Embodiment]
FIG. 5 is a schematic view showing the configuration of the second embodiment of the inflow flow rate measuring apparatus according to the present invention. In FIG. 5, a heater 2 for heating the pipe 1 is disposed on the outer circumference of the pipe 1 to be measured, and an infrared camera 11 for measuring the temperature of the pipe 1 is provided.

  In the second embodiment, the thermocouple thermometer and the data input device for measuring temperature in the first embodiment are replaced with the infrared camera 11, and other components are the same as those in the first embodiment. It is the same as the form.

  According to this configuration, a temperature image along the surface of the pipe 1 on both sides of the heater 2 is created using the infrared camera 11, and a numerical temperature distribution is obtained from the temperature image to obtain a flow direction and a flow rate inside the pipe 1. Can be measured. An example of the temperature image at this time is shown in FIG. Here, when the heater position is the center, it can be seen that the temperature on the right side in the figure is high and the flow is toward the right side (in the direction of the arrow).

  Therefore, also in the in-leak flow measuring device of this embodiment, a heater and an infrared camera are installed at arbitrary positions on the pipe as in the first embodiment, and the direction of the leak and the leak flow are determined from the degree of bias of the temperature distribution due to heating. Can be measured.

[Third Embodiment]
FIG. 7 is a schematic view showing the configuration of the third embodiment of the inflow rate measuring device according to the present invention. In FIG. 7, a heater 2 for heating the pipe is disposed on the outer circumference of the pipe 1 to be measured, and a fiber Bragg grating 12 for measuring the temperature of the pipe 1 is provided. The temperature sensor used is provided.

  In the third embodiment, the thermocouple thermometer for measuring temperature in the first embodiment is replaced with a fiber Bragg grating 12, and other components are the same as those in the first embodiment. It is.

  Here, the fiber Bragg grating 12 irradiates the core of the optical fiber with ultraviolet rays, and the refractive index changes in a period of the wavelength order of the light. Only a specific wavelength among the light incident on the fiber Bragg grating 12 is used. Is reflected. The reflected wavelength depends on the refractive index and its period, and the temperature is measured by utilizing the property that changes as the temperature is applied.

  According to this configuration, it is possible to measure the flow direction and flow rate inside the pipe 1 by performing temperature measurement using the temperature measuring means by the fiber Bragg grating 12.

  Therefore, also in the in-leak flow measuring device of the present embodiment, the heater 2 and the fiber Bragg grating 12 are mounted at an arbitrary position of the pipe 1 as in the first embodiment, and the leakage of the temperature distribution due to the heating degree is determined. Direction and leak flow can be measured. Furthermore, by using the fiber Bragg grating 12, multipoint measurement can be performed with a single fiber, and there is also an effect that wiring can be simplified particularly when a large number of pipes are targeted.

[Fourth Embodiment]
FIG. 8 is a schematic view showing the configuration of the fourth embodiment of the inleak flow measuring device according to the present invention. In FIG. 8, a heater 2 for heating the pipe is disposed on the outer circumference of the pipe 1 to be measured, and a thermo tape 13 is attached to the surface of the pipe 1 so that the video camera 14 images the thermo tape. Is provided.

  In the fourth embodiment, the thermocouple thermometer and the data input device for measuring temperature in the first embodiment are replaced with a thermo tape 13 and a video camera 14, and other components are as follows. This is the same as in the first embodiment.

  Here, the thermotape is a temperature indicating material that uses a chemical change due to a temperature of a substance and measures temperature by a color change or a density change corresponding to the temperature.

  According to this configuration, the thermo tape 13 and the video camera 14 are used to create a temperature image along the pipe surface on both sides of the heater, and the numerical distribution of temperature is obtained from the temperature image to obtain the flow direction inside the pipe. The flow rate can be measured. An example of the temperature image at this time is substantially the same as the image by the infrared camera shown in FIG.

  Therefore, also in the in-leak flow measuring device of the present embodiment, a heater, a thermo tape, and a video camera are installed at arbitrary positions on the pipe as in the first embodiment, and the direction of the leak is determined from the degree of temperature distribution bias due to heating. And the leak flow rate can be measured.

Schematic which shows the structure of 1st Embodiment of the inleak flow rate measuring apparatus which concerns on this invention. The graph which shows the example of the temperature distribution measurement result by the inleak flow measuring device of a 1st embodiment. The graph which shows the example of the time change of the bias distribution calculation result of the temperature distribution by the inleak flow measuring device of a 1st embodiment. The graph which shows the example of the relationship between the bias | inclination degree of the temperature distribution memorize | stored in the reference | standard data storage device, and the leak flow rate in the inleak flow measurement apparatus of 1st Embodiment. Schematic which shows the structure of 2nd Embodiment of the leak flow measuring device which concerns on this invention. The figure which shows an example of the measurement result image by the infrared camera obtained with the inleak flow measurement apparatus of 2nd Embodiment. Schematic which shows the structure of 3rd Embodiment of the inleak flow measuring device which concerns on this invention. Schematic which shows the structure of 4th Embodiment of the leak flow measuring device which concerns on this invention.

Explanation of symbols

1: Piping 2: Heater 3: Heating amount control device 4a, 4b, 4c, 4d: Thermocouple thermometer (temperature measuring means)
5: Data input device 6: Data recording device (data recording means)
7: Arithmetic unit (calculation means)
8: Reference data storage device (reference data storage means)
9: Comparison determination device (determination means)
10: Display device 11: Infrared camera (temperature measuring means)
12: Fiber Bragg grating (temperature measuring means)
13: Thermo tape (temperature measuring means)
14: Video camera

Claims (6)

A heater that is provided outside the pipe to be measured and heats part of the length of the pipe;
A plurality of temperature measurement means for measuring the surface temperature of the pipe provided on each side in the length direction of the pipe of the part heated by the heater;
Calculating means for calculating the temperature distribution of the pipe length direction from the measured values measured by the temperature measuring means of these,
A reference data storage unit that has stored beforehand the relationship between the pipe flow rate and the calculated temperature distribution by the computing means,
A determination unit that compares the temperature distribution calculated by the calculation unit with the lengthwise temperature distribution stored in advance in the reference data storage unit to obtain a flow rate in the pipe;
An in-leak flow rate measuring device comprising: 2. The leak according to claim 1, further comprising means for measuring a surface temperature of the pipe before heating by the heater and correcting a measured temperature value after the heating using a measurement result of the surface temperature of the pipe. Flow measurement device. The inleak flow measuring device according to claim 1 or 2, wherein a thermocouple is used as the temperature measuring means . Inriku flow rate measuring device according to claim 1 or 2, characterized by using an infrared camera as the temperature measuring means. The in-leak flow measuring device according to claim 1 or 2 , wherein multipoint measurement using an optical fiber is used as the temperature measuring means. The inleak flow rate measuring apparatus according to claim 1 or 2 , wherein a thermo tape using a color change caused by a chemical reaction is used as the temperature measuring means.

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