JP5676315B2 - Fluid identification device and fluid identification method - Google Patents

Description

  The present invention relates to a fluid identification device and a fluid identification method for identifying the type of fluid present in a tubular member.

  In the ground, tubular members such as a gas pipe for supplying city gas, a water pipe for supplying water, and a sewer pipe for collecting sewage are embedded. When performing excavation work of soil, those tubular members may be exposed. In such a case, whether or not the exposed tubular member is used effectively, and if it is used effectively, the fluid (for example, water or city gas) flowing through the inside is used. It is necessary to determine the type. This is because when the tubular member is effectively used, it is necessary to take an appropriate safety measure depending on the type of fluid flowing through the tubular member.

  Conventionally, as a method for determining the type of fluid existing inside the tubular member, a method by drilling, a method using a neutron moisture meter, and a clamp-on type ultrasonic flow meter (for example, see Patent Document 1 below) are used. The method used has been used. However, the method by drilling is inefficient because the tubular member is once destroyed by the drilling operation and a recovery operation after the determination is required. Moreover, in the method using a neutron moisture meter, although determination can be made nondestructively, it is only possible to determine whether or not moisture is present inside the tubular member, up to the determination of the type of fluid other than moisture. I can't. Although the method using a gas clamp-on type ultrasonic flowmeter can perform nondestructive determination, there are restrictions on application conditions regarding the material, outer shape, internal pressure, and the like of the tubular member.

  That is, the present condition is that the effective method which can identify easily the kind of the fluid which exists in the inside of a tubular member without special restrictions has not yet been established.

JP 2009-270882 A

  The present invention has been made in view of the above problems, and provides a fluid identification device and a fluid identification method that can easily identify the type of fluid present in a tubular member without any particular limitation. Objective.

The characteristic configuration of the fluid identification device according to the present invention is:
A transmitting probe that is disposed on the outer peripheral surface of the tubular member and transmits ultrasonic waves;
Of the ultrasonic waves transmitted from the transmission probe, transmitted through the tubular member and propagating through the tube, and transmitted from the transmission probe, arranged on the outer peripheral surface of the tubular member A receiving probe for receiving a propagating wave in the main body that propagates in the main body of the tubular member of the ultrasonic wave; and
A canceling probe that is arranged on the outer peripheral surface of the tubular member separately from the transmitting probe and the receiving probe, and transmits a canceling wave that cancels the propagation wave in the main body,
For at least a predetermined period before the time when the transmitted propagation wave is received by the receiving probe, according to the received waveform of the ultrasonic wave received by the receiving probe, A waveform adjustment unit that adjusts at least one of the phase, amplitude, and frequency of the cancellation wave so that the amplitude of the combined wave with the cancellation wave is smaller than the transmitted propagation wave as a whole;
In a state where the cancel wave adjusted by the waveform adjusting unit is transmitted from the canceling probe, the transmission probe receives the transmitted propagation wave, and the transmitting probe transmits ultrasonic waves. A sound speed calculation unit that calculates a propagation speed of ultrasonic waves inside the tubular member based on a time difference from when the transmitted propagation wave is received by the reception probe after the transmission of
And a fluid determination unit that determines a type of fluid existing inside the tubular member based on the propagation velocity calculated by the sound speed calculation unit.

According to the above characteristic configuration, the transmitted propagation wave that propagates through the tubular member through the tubular member among the ultrasonic waves transmitted from the transmitting probe disposed on the outer peripheral surface of the tubular member is transmitted by the transmitting probe. Based on the time difference between the transmission from the child and the reception probe, the sound velocity calculation unit calculates the ultrasonic wave propagation speed inside the tubular member. Since the ultrasonic propagation speed varies depending on the type of fluid as a medium, the fluid determination unit determines the type of fluid existing inside the tubular member based on the propagation speed calculated as described above. be able to.
At this time, the type of fluid (including liquid and gas) existing inside the tubular member can be determined without puncturing or destroying the tubular member and without any restriction on the material, outer shape, internal pressure, etc. of the tubular member. . That is, it is possible to realize a fluid identification device that can easily identify the type of fluid existing inside the tubular member without any particular limitation.

  Further, according to the above characteristic configuration, the inside of the main body that propagates in the main body portion of the tubular member from the canceling probe disposed on the outer peripheral surface of the tubular member separately from the transmitting probe and the receiving probe. A cancellation wave that cancels the propagation wave can be transmitted. For this reason, it is possible to effectively cancel only the propagation wave in the main body among the ultrasonic waves (including the transmission propagation wave and the propagation wave in the main body) transmitted from the transmission probe, and transmit the propagation wave in the main body. Propagation waves can be clearly identified. That is, it is possible to improve the S / N ratio when the reception probe receives the transmitted propagation wave as compared with the case where such a cancel operation is not executed. Therefore, the time difference until the transmitted propagation wave is received by the receiving probe and the propagation speed of the ultrasonic wave inside the tubular member based on the time difference can be calculated with high accuracy. Therefore, the type of fluid existing inside the tubular member can be accurately determined.

Furthermore, according to the above characteristic configuration, the ultrasonic wave transmitted from the transmitting probe and the cancel wave transmitted from the canceling probe are respectively in the propagation state, at the specific timing and at the specific position (amplitude). , Determined by frequency and phase) cannot be uniquely specified. That is, the state of these waves varies depending on conditions such as the material and shape of the tubular member or the external environment. However, with regard to specific conditions, a preliminary test is performed in advance, while referring to a received wave (here, a composite wave of a transmitted propagation wave and a propagation wave in the main body) received by the receiving probe, It is possible to adjust the cancellation wave (mainly frequency, oscillation timing, and amplitude thereof) so as to attenuate the propagation wave. In general, the propagation wave in the main body reaches the receiving probe in advance of the transmitted propagation wave, so appropriate cancellation in the time domain from the arrival of the propagation wave in the main body until the transmission propagation wave arrives. By specifying the wave, a cancel operation for effectively canceling the propagation wave in the main body can be realized.
In view of this point, according to the above configuration, for example, by adjusting at least one of the phase, amplitude, and frequency of the cancellation wave according to the reception waveform of the ultrasonic wave received by the receiving probe, As a whole, the amplitude of the combined wave of the main body propagation wave and the cancellation wave can be made smaller than that of the transmission propagation wave. Therefore, the S / N ratio when the receiving probe receives the transmitted propagation wave can be sufficiently improved according to the actual situation at the time of measurement, and the type of fluid existing inside the tubular member can be accurately determined. Can be determined.

Also,
The arrival time data indicating the arrival time until the propagation wave in the main body from the transmission probe reaches the canceling probe, and the waveform data indicating the waveform of the propagation wave in the main body, the tubular A recording device prerecorded according to at least one of the material of the member, the pipe diameter, and the pipe thickness;
The canceling probe transmits, as the canceling wave, an antiphase wave that has a waveform that is calculated based on the arrival time data and the waveform data and has a phase opposite to the propagation wave in the main body. This is preferable.

The arrival time until the in-body propagating wave reaches the canceling probe and the waveform of the in-body propagating wave may vary depending on the material of the tubular member, the tube diameter, the tube thickness, and the like. Therefore, as described above, the recording device is provided with the arrival time data and the waveform data corresponding to at least one of the material, the tube diameter, and the tube thickness of the tubular member. Based on the recorded data, it is possible to relatively easily calculate an anti-phase wave having a waveform that is opposite in phase to the intra-body propagation wave. Therefore, based on the antiphase wave calculated as described above, a cancel wave that can effectively cancel the propagation wave in the main body can be transmitted relatively easily.
In addition, by first transmitting the antiphase wave calculated as described above, and further adjusting the waveform of the cancellation wave as described above, the cancellation wave that can effectively cancel the propagation wave in the main body is shortened. As a result, such a cancellation wave can be transmitted easily and appropriately.

Also,
It is preferable that the configuration includes two canceling probes arranged in plane symmetry with respect to a virtual plane on which the axis of the tubular member and the receiving probe are arranged.

  According to this configuration, the in-body propagating wave propagating from the transmitting probe toward one side in the circumferential direction of the tubular member and the in-body propagating wave propagating toward the other side in the circumferential direction are converted into the tubular member. It is possible to cancel in the same manner by two canceling probes arranged in plane symmetry with respect to a virtual plane in which the axis of the receiving line and the receiving probe are arranged. Therefore, the propagation wave in the main body can be canceled relatively easily, and the S / N ratio when the receiving probe receives the propagation wave in the main body can be improved.

Also,
It is preferable that the transmitting probe and the receiving probe provided separately are arranged to face each other so as to sandwich the tubular member in the radial direction on the virtual plane.

  According to this configuration, on the virtual plane on which the axis of the tubular member and the receiving probe are arranged, the individual transmitting probe and the receiving probe face each other so as to sandwich the tubular member in the radial direction. Since the transmission element is arranged, the transmission probe wave from the transmission probe can be received by the reception probe with relatively little attenuation. Thus, for example, a transmission probe and a reception probe are made common, and a reflected wave of a transmitted propagation wave on the inner peripheral surface of the tubular member is arranged at the same position as the transmission probe. Compared with the case where the probe is received by the probe, the detection signal (signal) when the receiving probe receives the transmitted propagation wave becomes large. Therefore, the type of fluid existing inside the tubular member can be accurately determined in a state where the S / N ratio when the receiving probe receives the transmitted propagation wave is large.

The characteristic configuration of the fluid identification method according to the present invention is:
A transmission step of transmitting ultrasonic waves from a transmission probe disposed on the outer peripheral surface of the tubular member;
Of the ultrasonic waves transmitted from the transmission probe, the transmission wave transmitted through the tubular member and propagated in the tube by the reception probe disposed on the outer peripheral surface of the tubular member, and the transmission A reception step of receiving a propagation wave in the main body that propagates in the main body of the tubular member among the ultrasonic waves transmitted from the probe;
A cancel wave transmission that transmits a cancel wave that cancels the propagation wave in the main body using a cancel probe disposed on the outer peripheral surface of the tubular member separately from the transmission probe and the reception probe. Steps,
In the reception step, at least the transmission propagation wave is received by the reception probe, and the main body according to the reception waveform of the ultrasonic wave received by the reception probe for a predetermined period before the time point A waveform adjustment step of adjusting at least one of the phase, amplitude, and frequency of the cancellation wave so that the amplitude of the combined wave of the inner propagation wave and the cancellation wave is smaller than the transmitted propagation wave as a whole;
The propagation speed of the ultrasonic wave inside the tubular member is calculated based on the time difference from when the ultrasonic wave is transmitted by the transmitting probe to when the transmitted propagation wave is received by the receiving probe. A sound speed calculation step;
A fluid determination step of determining the type of fluid present in the tubular member based on the propagation velocity calculated in the sound speed calculation step ,
In a state where the cancellation wave adjusted in the waveform adjustment step is transmitted from the canceling probe, the transmission probe receives the transmitted propagation wave, and the sound velocity calculation step and the fluid determination step are performed. The point is to execute .

According to this characteristic configuration, the transmitted propagation wave that propagates through the tubular member through the tubular member among the ultrasonic waves transmitted from the transmitting probe disposed on the outer peripheral surface of the tubular member is transmitted by the transmitting probe. On the basis of the time difference from when the signal is transmitted to when it is received by the receiving probe, the ultrasonic wave propagation speed inside the tubular member is calculated in the sound speed calculation step. Since the propagation speed of ultrasonic waves varies depending on the type of fluid as a medium, in the fluid determination step, the type of fluid existing inside the tubular member is determined based on the propagation speed calculated as described above. be able to.
At this time, the type of fluid (including liquid and gas) existing inside the tubular member can be determined without puncturing or destroying the tubular member and without any restriction on the material, outer shape, internal pressure, etc. of the tubular member. . That is, it is possible to realize a fluid identification method that can easily identify the type of fluid existing inside the tubular member without any particular limitation.

  Further, according to the above characteristic configuration, in the cancel wave transmitting step, the main body of the tubular member from the canceling probe disposed on the outer peripheral surface of the tubular member separately from the transmitting probe and the receiving probe. A cancellation wave is transmitted to cancel the propagation wave in the main body that propagates in the unit. For this reason, it is possible to effectively cancel only the propagation wave in the main body among the ultrasonic waves (including the transmission propagation wave and the propagation wave in the main body) transmitted from the transmission probe, and transmit the propagation wave in the main body. Propagation waves can be clearly identified. That is, compared with the case where such a cancellation wave transmission step is not executed, the S / N ratio when the reception probe receives the transmitted propagation wave can be improved. Therefore, the time difference until the transmitted propagation wave is received by the receiving probe and the propagation speed of the ultrasonic wave inside the tubular member based on the time difference can be calculated with high accuracy. Therefore, the type of fluid existing inside the tubular member can be accurately determined.

Furthermore, according to the above-described characteristic configuration, as described above, the state of the ultrasonic wave transmitted from the transmission probe and the cancellation wave transmitted from the cancellation probe are determined by the material of the tubular member, It varies depending on conditions such as shape or external environment. However, with regard to specific conditions, a preliminary test is performed in advance, while referring to a received wave (here, a composite wave of a transmitted propagation wave and a propagation wave in the main body) received by the receiving probe, It is possible to adjust the cancellation wave (mainly frequency, oscillation timing, and amplitude thereof) so as to attenuate the propagation wave.
In view of this point, according to the above configuration, in the waveform adjustment step, the amplitude of the combined wave of the propagation wave in the main body and the cancellation wave is entirely determined according to the reception waveform of the ultrasonic wave received by the reception probe. As a result, at least one of the phase, amplitude, and frequency of the cancellation wave is adjusted so as to be smaller than the transmitted propagation wave. And by setting it as the structure which performs each step to the fluid determination step in the state which has transmitted the cancellation wave adjusted by the waveform adjustment step, S / at the time of the probe for reception receiving a transmitted propagation wave The N ratio can be sufficiently improved according to the actual situation at the time of measurement, and the type of the fluid existing inside the tubular member can be accurately determined.

Furthermore, according to the above characteristic configuration, noise in a predetermined period before the time point when the transmitted propagation wave is received by the receiving probe, which can greatly affect the detection of the transmitted propagation wave by the receiving probe, It can be effectively reduced. Therefore, both simplicity and effectiveness of the waveform adjustment step can be ensured.

It is a mimetic diagram showing the whole fluid discriminating device composition concerning an embodiment. It is a schematic diagram which shows the propagation state of the ultrasonic wave transmitted from the probe for transmission. It is an example of the reception waveform in the probe for reception at the time of non-operation of the probe for cancellation. It is an example of the received waveform in the probe for reception at the time of the action | operation of the probe for cancellation. It is a schematic diagram which shows the fluid identification apparatus which concerns on other embodiment. It is a schematic diagram which shows notionally the cancellation wave transmission step which concerns on other embodiment.

  Embodiments of the present invention will be described with reference to the drawings. The fluid identification device 1 according to the present embodiment determines the type of the gas G (a kind of fluid) existing inside the tubular member P such as a gas pipe nondestructively (without destroying the tubular member P). This is a gas type identification device. As shown in FIG. 1, the fluid identification apparatus 1 includes a transmission probe 12 that transmits ultrasonic waves, and a reception probe 14 that receives ultrasonic waves transmitted from the transmission probe 12. ing. In addition, the fluid identification device 1 includes a sound speed calculation unit 24 that calculates a sound speed (propagation speed) V inside the tubular member P of the transmitted propagation wave Wt (see FIG. 2) propagating inside the tubular member P, and a calculation. And a fluid determination unit 25 that determines the type of the gas G existing inside the tubular member P based on the sound velocity V. Furthermore, the fluid identification device 1 according to the present embodiment includes a canceling probe 18 that transmits a canceling wave Wc that cancels the in-body propagating wave Wb (see FIG. 2) that propagates in the main body of the tubular member P. Yes. As a result, the type of the gas G existing inside the tubular member P can be easily and accurately identified without any particular limitation. Hereinafter, the fluid identification device 1 according to the present embodiment will be described in detail.

1. 1. Hardware Configuration of Fluid Identification Device As shown in FIG. 1, the fluid identification device 1 includes a transmission probe 12, a reception probe 14, a cancellation probe 18, and a control device 20 as main components. I have. The transmitting probe 12, the receiving probe 14, and the canceling probe 18 are disposed in contact with the outer peripheral surface of the tubular member P, respectively. The transmission probe 12, the reception probe 14, and the cancellation probe 18 are each configured to exchange information with the control device 20.

  The transmission probe (transmission ultrasonic probe) 12 is a transducer including a piezoelectric element that mutually converts electricity and sound, and is an ultrasonic transmission device that transmits ultrasonic waves. As such a piezoelectric element, for example, a piezoelectric ceramic such as PZT (lead zirconate titanate) or a polymer piezoelectric element such as PVDF (polyvinylidene fluoride) is used. The transmission probe 12 includes a vibrator having electrodes formed at both ends of the piezoelectric element. When a voltage is applied between the electrodes of the vibrator in response to a command from the control device 20, the piezoelectric element expands and contracts. To do. Due to this expansion and contraction, an ultrasonic wave is generated from the vibrator, and the generated ultrasonic wave is transmitted toward the tubular member P. “Ultrasound” is a frequency higher than the human audible frequency (for example, 20 kHz or more) among elastic waves generated when a sound medium such as gas, liquid, solid, etc. receives vibration of a sounding body (the above vibrator). ) Elastic wave.

  As shown in FIG. 2, the ultrasonic wave transmitted from the transmission probe 12 is divided into a transmitted propagation wave Wt and an intra-body propagation wave Wb and propagates through the respective media. Here, the transmitted propagation wave Wt is transmitted through the tubular member P among the ultrasonic waves transmitted from the transmission probe 12, and the gas G existing inside the tubular member P is used as a medium (in the tubular member P). This is an ultrasonic wave propagating in a space defined by the inner peripheral surface.

  On the other hand, the in-body propagating wave Wb is the ultrasonic wave transmitted from the transmitting probe 12 and the material (for example, carbon steel, stainless steel, etc.) constituting the main body portion of the tubular member P is used as a medium. Ultrasound propagating in the main body. When an ultrasonic wave is transmitted from the transmission probe 12, a part of the ultrasonic wave propagates in the main body portion of the tubular member P as a main body propagation wave Wb without passing through the tubular member P. In this embodiment, the in-body propagating wave Wb propagates in the body portion of the tubular member P divided into both sides in the circumferential direction when viewed from the axial direction. That is, the in-body propagation wave Wb includes a wave propagating clockwise in the tubular member P toward one side in the circumferential direction in FIG. 2 and a wave propagating counterclockwise toward the other side in the circumferential direction. .

  The reception probe (reception ultrasonic probe) 14 is a transducer having the same configuration as that of the transmission probe 12, and is an ultrasonic reception device that receives ultrasonic waves. The reception probe 14 receives both the above-described transmitted propagation wave Wt and in-body propagation wave Wb among the ultrasonic waves transmitted from the transmission probe 12. When the receiving probe 14 receives an ultrasonic wave, the piezoelectric element of the receiving probe 14 is physically expanded and contracted by the action of the ultrasonic wave. This expansion and contraction generates a potential difference between the electrodes of the vibrator. An electric signal based on the generated potential difference is sent to the control device 20 as a received signal.

  In the present embodiment, as shown in FIGS. 1 and 2, each of the transmission probe 12 and the reception probe 14 is provided individually. Further, the transmission probe 12 and the reception probe 14 are arranged to face each other so as to sandwich the tubular member P in the radial direction at the same axial direction position of the tubular member P. That is, the transmission probe 12 and the reception probe 14 are arranged on opposite sides of the axis L on the virtual plane Z passing through the axis L of the tubular member P.

  The fluid identification apparatus 1 according to the present embodiment includes a canceling probe 18 in addition to the transmitting probe 12 and the receiving probe 14. The canceling probe (cancellation ultrasonic probe) 18 is a transducer having the same configuration as the transmitting probe 12 and the receiving probe 14, and an ultrasonic wave is generated separately from the transmitting probe 12. It is the 2nd ultrasonic transmission apparatus which transmits. In the present embodiment, the fluid identification device 1 includes two canceling probes 18 a and 18 b as such a canceling probe 18. These two canceling probes 18a and 18b are arranged in plane symmetry with respect to a virtual plane Z on which the axis L of the tubular member P and the receiving probe 14 are arranged. Note that the “plane symmetry” means that even if there is some positional deviation, it can be regarded as substantially plane symmetry as a whole.

  In the present embodiment, the two canceling probes 18a and 18b further sandwich the tubular member P in the radial direction at the same axial position of the transmitting probe 12, the receiving probe 14, and the tubular member P. So as to face each other. Therefore, in the present embodiment, a total of four ultrasonic probes, that is, the transmitting probe 12, the receiving probe 14, and the two canceling probes 18a and 18b, have the same axial position of the tubular member P. Are distributed evenly in the circumferential direction. That is, the first canceling probe is located at the midpoint of the propagation path of the in-body propagating wave Wb from the transmitting probe 12 toward the receiving probe 14 toward the one side along the circumferential direction of the tubular member P. The second element 18a is arranged, and the second point is located at the intermediate point of the propagation path of the in-body propagating wave Wb from the transmitting probe 12 to the receiving probe 14 toward the other side along the circumferential direction of the tubular member P. A canceling probe 18b is arranged. Each probe 12, 14, 18 a, 18 b is positioned by a predetermined mounting jig (not shown) installed so as to surround the periphery of the tubular member P, and the outer periphery of the tubular member P Placed in the section. The canceling probes 18a and 18b transmit a cancel wave Wc that cancels the in-body propagating wave Wb propagating in the main body of the tubular member P. Details of the cancel wave Wc will be described later.

2. Software configuration of fluid identification device (control device configuration)
As shown in FIG. 1, the control device 20 provided in the fluid identification device 1 includes a first transmission control unit 21, a second transmission control unit 22, a received signal processing unit 23, a sound speed calculation unit 24, a fluid determination unit 25, and A waveform adjustment unit 26 is provided. These are configured to be able to exchange information with each other. In FIG. 1, a typical information transmission direction is indicated by an arrow “→”. In addition, the fluid identification method according to the present invention is executed by organically cooperating and cooperating with each of the probes 12, 14, and 18 described above and the functional units of the control device 20 described below. The

  The first transmission control unit 21 is a functional unit that controls transmission of ultrasonic waves (ultrasonic transmission) from the transmission probe 12. The first transmission control unit 21 generates a burst-wave electric signal (voltage signal) having a predetermined amplitude and a resonance frequency of the tubular member P mainly determined according to the thickness (tube thickness) of the tubular member P. The resonance frequency of the tubular member P can be calculated based on the tube thickness of the tubular member P. The generated electrical signal is sent to the transmission probe 12. The transmission probe 12 converts the received burst-wave electric signal into an ultrasonic wave and transmits an ultrasonic pulse toward the tubular member P. The “transmission step” in the present invention is executed by the first transmission control unit 21.

  The reception signal processing unit 23 is a functional unit that receives an electrical signal (reception signal) based on the ultrasonic wave received by the reception probe 14 in the “reception step” of the present invention and processes the reception signal. The reception signal processing unit 23 removes an electrical signal based on an ultrasonic wave having a specific frequency component through a filter or the like. The reception signal processing unit 23 converts an analog reception signal into a digital reception signal via an analog / digital conversion circuit (A / D conversion circuit) or the like. The reception signal processing unit 23 outputs a digital reception signal in a predetermined frequency range to the sound speed calculation unit 24 and the display device 40 (a monitor or the like). On the display device 40, the received signal received is visualized and displayed as a received waveform. The reception signal processing unit 23 also outputs the reception signal to a waveform adjustment unit 26 described later.

  The sound speed calculation unit 24 is a functional unit that calculates the sound speed of ultrasonic waves inside the tubular member P (hereinafter sometimes simply referred to as “in-tube sound speed”) V. The sound speed calculation unit 24 receives the reception signal from the reception signal processing unit 23, and calculates the in-tube sound speed V by analyzing the reception signal. As described above, the ultrasonic wave transmitted from the transmission probe 12 includes the transmitted propagation wave Wt and the in-body propagation wave Wb. Here, due to the difference in acoustic impedance between the gas G existing inside the tubular member P and the material constituting the main body portion of the tubular member P, the transmitted propagation wave Wt can be sent much more than the in-body propagation wave Wb. To the receiving probe 14. The sound velocity calculation unit 24 calculates the in-tube sound velocity V based on the time difference ΔT from when the ultrasonic wave is transmitted by the transmission probe 12 until the transmitted propagation wave Wt is received by the reception probe 14. Is calculated. The sound speed calculation unit 24 executes the “sound speed calculation step” in the present invention.

  More specifically, a clock pulse is generated by a clock pulse generation circuit or the like in the control device 20, and the sound velocity calculation unit 24 receives the ultrasonic wave from the transmission probe 12 and then receives the probe. By counting the number of clock pulses until it is detected at 14 that the transmitted propagation wave Wt is received, the time difference ΔT between them is measured. The sound speed calculation unit 24 calculates the in-tube sound speed V based on the information of the measured time difference ΔT and the information of the known inner diameter φ of the tubular member P (see FIG. 2). That is, the sound velocity calculation unit 24 calculates the in-tube sound velocity V by dividing the inner diameter φ of the tubular member P by the time difference ΔT (V = φ / ΔT). The sound speed calculation unit 24 outputs information on the calculated in-pipe sound speed V to the fluid determination unit 25.

  The fluid determination unit 25 is a functional unit that determines the type of the gas G present in the tubular member P based on the calculated in-tube sound velocity V. The speed of sound of ultrasonic waves varies depending on the type of fluid that is a medium. In the present embodiment, information on the ultrasonic sound velocity (theoretical sound velocity) corresponding to the type of fluid (for example, water, oil, air, methane gas, etc.) is stored as sound velocity data 31 in a recording device 30 such as a RAM or a ROM. Pre-recorded. In addition, since the actual sound speed of the ultrasonic wave can change depending on the state of the medium, the sound speed data 31 is recorded as information on the sound speed further subdivided according to one or more of the temperature, density, and pressure of the medium. It is preferable to adopt the configuration. The fluid determination unit 25 compares the calculated in-tube sound speed V with the sound speed data 31 and associates the calculated sound speed with the sound speed that matches the calculated in-tube sound speed V (closest when there is no complete match). The fluid information is read from the sound speed data 31. The “fluid determination step” in the present invention is executed by the fluid determination unit 25.

  As described above, the fluid identification device 1 can nondestructively determine the type of the gas G existing inside the tubular member P. FIG. 3 shows an example of a received waveform at the receiving probe 14. As can be understood from FIG. 3, the received signal (transmitted wave signal) by the transmitted propagation wave Wt is superimposed on noise having a large amplitude. This noise is mainly caused by the in-body propagating wave Wb that propagates in the main body of the tubular member P and circulates over a plurality of rounds. As described above, in a state where the transmitted wave signal is superimposed on noise having a large amplitude, the S / N ratio (signal / noise ratio) is reduced, and the transmission probe wave Wt is received at the reception probe 14. The detection accuracy may be reduced. As a result, the calculation of the in-pipe sound velocity V may be inaccurate, and the determination of the type of the gas G present in the tubular member P may be inaccurate.

  In order to avoid the inconveniences as described above, the fluid identification device 1 according to the present embodiment includes the above-described canceling probe 18 and the second transmission control unit 22 in the control device 20. The second transmission control unit 22 is a functional unit that controls transmission (cancellation wave transmission) of an ultrasonic wave (cancellation wave Wc) from the canceling probe 18. Here, the cancel wave Wc is an ultrasonic wave that cancels the in-body propagating wave Wb propagating in the main body of the tubular member P. In the present embodiment, arrival time data 32 and waveform data 33 on the premise that the four probes 12, 14, 18 a, 18 b are uniformly distributed on the outer peripheral surface of the tubular member P in the circumferential direction. Is recorded in advance in the recording device 30.

  Here, the arrival time data 32 is data representing the arrival time (delay time) until the in-body propagating wave Wb transmitted by the transmission probe 12 reaches the position of the canceling probe 18. The waveform data 33 is data representing the received waveform of the in-body propagating wave Wb when it is assumed that the receiving probe 14 is disposed at the position of the canceling probe 18. That is, the waveform data 33 includes information on the amplitude and frequency of the in-body propagation wave Wb propagating through the position of the canceling probe 18, and the arrival time data 32 includes information on the phase. In the present embodiment, the arrival time data 32 and the waveform data 33 are actually stored in the main body by the receiving probe 14 at the position where the receiving probe 14 is arranged at the position of the canceling probe 18. It is prepared in advance as measured data obtained by actually measuring the time until the inner propagation wave Wb is received and the received waveform at that time. In addition, the arrival time until the in-body propagating wave Wb transmitted by the transmitting probe 12 reaches the position of the canceling probe 18 and the received waveform at that time are expressed by the material of the tubular member P, the tube diameter, It may vary depending on the tube thickness. Therefore, in the present embodiment, the arrival time data 32 and the waveform data 33 are subdivided according to at least one of the material, tube diameter, and tube thickness of the tubular member P and recorded in advance. Here, the “tube diameter” includes one or both of an inner diameter and an outer shape.

  Based on the arrival time data 32 and the waveform data 33, the second transmission control unit 22 has the same amplitude and frequency as the in-body propagating wave Wb when reaching the position of the canceling probe 18, and has an opposite phase. An anti-phase wave having a waveform (the phase is shifted by π) is calculated. The second transmission control unit 22 generates an electric signal (voltage signal) corresponding to the calculated antiphase wave. The generated electrical signal is sent to the canceling probe 18. The canceling probe 18 converts the received electrical signal into an ultrasonic wave (cancellation wave Wc), and transmits the cancellation wave Wc toward the tubular member P. In the present embodiment, since the arrival time data 32 and the waveform data 33 as described above are recorded in advance in the recording device 30, a cancel wave Wc that can effectively cancel the propagation wave Wb in the main body based on them is simply and appropriately applied. Can be sent to. The “canceling wave transmission step” in the present invention is executed by the second transmission control unit 22.

  In this way, from the canceling probe 18, an antiphase wave having a waveform having the same amplitude and frequency as the in-body propagating wave Wb and having an opposite phase is transmitted as the canceling wave Wc. The cancel wave Wc acts to interfere with the in-body propagating wave Wb that becomes noise when detecting the reception signal (transmitted wave signal) by the transmitted propagating wave Wt, and cancels out the in-body propagating wave Wb as the noise. To do. Thereby, the amplitude of the noise around the transmitted wave signal can be reduced and the S / N ratio can be improved. Therefore, the time difference ΔT until the transmission probe Wt is received by the receiving probe 14 and the in-tube sound velocity V based on the time difference ΔT can be accurately calculated. Therefore, according to the fluid identification device 1 according to the present embodiment, the type of the gas G existing inside the tubular member P can be accurately determined.

  By the way, in general, an ultrasonic wave cannot be uniquely specified at a specific timing and at a specific position in its propagation state, but varies depending on the material and shape of the tubular member P, the external environment, or the like. Further, the ultrasonic wave transmitted from the transmission probe 12 and the cancellation wave Wc transmitted from the cancellation probe 18 do not necessarily have the intended frequency and phase, respectively. Deviation may occur. Further, the propagation wave Wb in the main body may be attenuated to some extent when propagating in the main body portion of the tubular member P. Therefore, for example, even if a cancel wave Wc that can cancel the propagation wave Wb in the main body is theoretically transmitted from the canceling probe 18, the effect of improving the S / N ratio may be suppressed to be relatively small. Therefore, the fluid identification device 1 according to the present embodiment further includes the waveform adjustment unit 26 in the control device 20.

  The waveform adjustment unit 26 is a functional unit that adjusts the waveform of the cancellation wave Wc by adjusting the phase, amplitude, and frequency of the cancellation wave Wc. The waveform adjustment unit 26 has an amplitude of the combined wave Ws of the in-body propagation wave Wb and the cancellation wave Wc as a whole in comparison with the transmitted propagation wave Wt in accordance with the received waveform of the ultrasonic wave received by the receiving probe 14. The phase, amplitude, and frequency of the cancellation wave Wc are adjusted so as to decrease. In this example, the waveform adjustment unit 26 outputs an adjustment command for adjusting the phase, amplitude, and frequency of the cancellation wave Wc to the second transmission control unit 22. The second transmission control unit 22 outputs an electrical signal corresponding to the received adjustment command to the canceling probe 18. Thereby, the waveform of the cancellation wave Wc is adjusted. The “waveform adjustment step” in the present invention is executed by the cooperation of the waveform adjustment unit 26 and the second transmission control unit 22. In the present embodiment, such a waveform adjustment step is executed manually through the operator's hand while confirming the received signal displayed on the display device 40, for example.

  For example, even if a cancel wave Wc calculated based on the waveform data 33 is transmitted from the canceling probe 18, the frequency of the cancel wave Wc completely matches the frequency of the in-body propagating wave Wb. Not exclusively. Similarly, even if the cancellation wave Wc calculated based on the arrival time data 32 is transmitted from the cancellation probe 18, the phase of the cancellation wave Wc is completely opposite to the phase of the in-body propagation wave Wb. It is not always the case. Therefore, the frequency of the cancellation wave Wc is adjusted to match the frequency of the propagation wave Wb in the main body, and the phase of the cancellation wave Wc is adjusted to be opposite to the phase of the propagation wave Wb in the main body, thereby canceling. The effect of canceling the in-body propagating wave Wb by the wave Wc can be improved.

  Further, since the propagation wave Wb in the main body is attenuated to some extent when propagating in the main body portion of the tubular member P, the attenuation of the propagation wave Wb in the main body even if the frequency and phase of the cancellation wave Wc are adjusted as described above. There is a possibility that the amplitude of the synthesized wave Ws remains at a certain level depending on the degree of. Therefore, by further adjusting the amplitude of the cancellation wave Wc, the propagation wave Wb in the main body can be canceled as much as possible by the cancellation wave Wc.

  Actually, the propagation wave Wb in the main body includes a plurality of modes such as a longitudinal wave, a transverse wave, and a surface wave. In addition, various factors are complicatedly intertwined to generate a synthesized wave Ws. To do. For this reason, the entire period from when an ultrasonic wave is transmitted by the transmission probe 12 to when the transmission propagation wave Wt is received by the reception probe 14 (in FIG. 4, “internal propagation wave reception time range”). In general, it is difficult to make the amplitude of the synthesized wave Ws completely zero over the display. Nevertheless, by executing the waveform adjustment step as described above, the amplitude of the synthesized wave Ws can be greatly reduced according to the actual situation at the time of measurement, and the S / N ratio when receiving the transmitted wave signal is increased. Can be improved.

  In the present embodiment, in particular, a predetermined period (referred to as “target period B”; see FIG. 4) including the time point at which the transmitted propagation wave Wt is received by the receiving probe 14. As an object, the above-described waveform adjustment step is executed. The “predetermined period” in this case is, for example, 1/2 of the entire period from when the ultrasonic wave is transmitted by the transmitting probe 12 until the transmitted propagation wave Wt is received by the receiving probe 14. The period can be 10 to 1/2, or the period can be 1/5 to 1/3. In FIG. 4, a period that is ¼ of the entire period from when the ultrasonic wave is transmitted by the transmission probe 12 to when the transmitted propagation wave Wt is received by the reception probe 14 is the target period. An example in the case of B is shown. In this way, by setting only the target period B instead of the entire period until the transmitted propagation wave Wt is received by the receiving probe 14 as the target of waveform adjustment, both the simplicity and effectiveness of the waveform adjustment step are achieved. Can be secured.

  In relation to the provision of the second transmission control unit 22 and the waveform adjustment unit 26 as described above, the fluid identification device 1 according to this embodiment includes the waveform adjustment unit 26 and the second transmission control unit 22. Each step up to the fluid determination step is executed in a state in which the cancel wave Wc whose phase, amplitude, and frequency are adjusted by the function of the is transmitted from the canceling probe 18. That is, in the state where the cancellation wave Wc having a waveform adjusted according to the actual situation at the time of measurement is transmitted from the cancellation probe 18 so that the amplitude of the synthesized wave Ws can be significantly reduced, the reception probe is detected. The transmitted propagation wave Wt is received by the touch element 14, the received signal is processed by the received signal processing unit 23, the in-pipe sound speed V is calculated by the sound speed calculation unit 24, and the gas present inside the tubular member P by the fluid determination unit 25. The type of G is determined.

  An example of the received waveform at the receiving probe 14 in this case is shown in FIG. As can be understood by comparing FIG. 4 with FIG. 3 described above, only the noise caused by the propagation wave Wb in the main body is significantly reduced by including the cancellation wave transmission step and the waveform adjustment step. The reception signal (transmitted wave signal) by the transmitted propagation wave Wt is in a dominant state against such noise. This makes it possible to clearly identify the transmitted propagation wave Wt with respect to the in-body propagation wave Wb. That is, it is possible to greatly improve the S / N ratio when detecting a transmitted wave signal. Therefore, the sound speed calculation unit 24 can accurately calculate the time difference ΔT and the in-tube sound speed V based on the time difference, and the fluid determination unit 25 can accurately determine the type of the gas G existing inside the tubular member P. Judgment is possible.

  Further, in the present embodiment, the transmission probe 12 and the reception probe 14 that are individually provided are arranged to face each other so as to sandwich the tubular member P in the radial direction. For this reason, the reception probe 14 can receive the transmitted propagation wave Wt transmitted from the transmission probe 12 with relatively little attenuation. The two canceling probes 18a and 18b are symmetrical with respect to a virtual plane Z on which the transmitting probe 12 and the receiving probe 14 are arranged through the axis L of the tubular member P. Be placed. Therefore, the in-body propagating wave Wb propagating from the transmitting probe 12 toward one side in the circumferential direction of the tubular member P and the in-body propagating wave Wb propagating toward the other side in the circumferential direction are divided into two. The canceling wave Wc from the canceling probes 18a and 18b can be canceled in the same manner. In other words, since the two cancellation probes 18a and 18b can be controlled in the same manner by one second transmission control unit 22, the configuration of the control device 20 can be simplified.

  As described above, according to the fluid identification device 1 according to the present embodiment, the type of the gas G existing in the tubular member P can be easily and accurately identified without any particular restriction.

3. Other Embodiments Finally, other embodiments of the fluid identification device according to the present invention will be described. Note that the configurations disclosed in the following embodiments can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction arises.

(1) In the above-described embodiment, the case where one transmission probe 12 and one reception probe 14 are provided individually has been described as an example. However, the embodiment of the present invention is not limited to this. That is, a configuration in which only one transmission / reception probe 16 having both functions of the transmission probe 12 and the reception probe 14 in the above-described embodiment is provided (see FIG. 5). Is also one preferred embodiment of the present invention. Since the acoustic impedance differs greatly between the gas G present inside the tubular member P and the material constituting the main body of the tubular member P, a part of the transmitted propagation wave Wt is reflected and reflected by the inner peripheral surface of the tubular member P. Wave Wr. The reflected wave Wr propagates in the tubular member P in the direction opposite to the transmitted propagation wave Wt before reflection, and is received by the transmission / reception probe 16. In this case, the sound velocity calculation unit 24 determines whether the ultrasonic wave is transmitted from the transmitter / receiver probe 16 until the reflected wave Wr is finally received by the transmitter / receiver probe 16 based on the time difference ΔT. The speed of sound V can be calculated. Note that two canceling probes 18 a and 18 b are provided as the canceling probe 18, the first transmission control unit 21, the second transmission control unit 22, the received signal processing unit 23, and the fluid determination unit 25. The function of the waveform adjusting unit 26 and the like are the same as in the above embodiment.

  In this case, as shown in FIG. 5, the two canceling probes 18a and 18b are symmetrical with respect to a virtual plane Z on which the axis L of the tubular member P and the transmitting / receiving probe 16 are arranged. It is preferable that they are arranged. In the example shown in the figure, the two canceling probes 18a and 18b are arranged opposite to each other so as to sandwich the tubular member P in the radial direction at the same axial position of the transmitting / receiving probe 16 and the tubular member P. ing.

  In such a configuration, transmission and reception of ultrasonic waves (including the transmitted propagation wave Wt, the reflected wave Wr, and the in-body propagation wave Wb) are performed using the common transmission / reception probe 16, so that they are individually transmitted. The cost can be reduced as compared with the case where the ultrasonic probe is used. In addition, for example, even when the tubular member P to be determined is buried in the ground, the tubular member P is formed from the ground so that at least the transmitting / receiving probe 16 and the canceling probes 18a and 18b can be arranged. Since it is sufficient to expose the member P, the determination work can be simplified. Note that when a part of the transmitted propagation wave Wt is reflected to become the reflected wave Wr, the intensity of the received signal (reflected wave signal) by the reflected wave Wr is attenuated to be reduced, but the canceling probe 18 cancels it. Since the wave Wc is transmitted, noise caused by the in-body propagating wave Wb is significantly reduced, and there is no particular problem.

(2) In the above embodiment, the case where the waveform adjustment unit 26 adjusts all of the phase, amplitude, and frequency of the cancellation wave Wc has been described as an example. However, the embodiment of the present invention is not limited to this. That is, it is also one of the preferred embodiments of the present invention that the waveform adjusting unit 26 is configured to adjust one or two of the phase, amplitude, and frequency of the cancel wave Wc.

(3) In the above embodiment, the case where the waveform adjustment step is manually executed by the operator while confirming the reception signal displayed on the display device 40 has been described as an example. However, the embodiment of the present invention is not limited to this. That is, for example, a configuration in which the waveform adjustment step is automatically executed by the waveform adjustment unit 26 based on a predetermined algorithm is also one preferred embodiment of the present invention.

(4) In the above-described embodiment, the transmission propagation wave is a period before the time when the transmission propagation wave Wt is received by the reception probe 14 and after the ultrasonic wave is transmitted by the transmission probe 12. The case where only a part of the whole period until Wt is received by the receiving probe 14 is the target period B has been described as an example. However, the embodiment of the present invention is not limited to this. That is, for example, the entire period from when an ultrasonic wave is transmitted by the transmitting probe 12 until the transmitted propagation wave Wt is received by the receiving probe 14 may be the target period B. It is one of the preferred embodiments of the invention. It is also one of preferred embodiments of the present invention that a predetermined period before and after the time point when the transmitted propagation wave Wt is received by the receiving probe 14 is the target period B. .

(5) In the above embodiment, the case where the waveform of the cancel wave Wc is determined based on the arrival time data 32 and the waveform data 33 recorded in advance in the recording device 30 has been described as an example. However, the embodiment of the present invention is not limited to this. That is, for example, the reception probe 14 receives the propagation wave Wb in the main body as a trigger, and the cancel wave Wc may be determined based on the actually received body propagation wave Wb. This is one of the preferred embodiments of the present invention. The basic concept in this case is schematically shown in FIG. As shown in this figure, the propagation time in the main body is calculated from the time (indicated as “reception time”) until the propagation wave Wb in the main body is actually received by the receiving probe 14 and the measured data on the received waveform at that time. The time until the wave Wb reaches the position of the canceling probe 18 (displayed as “delay time”) and the waveform at the position are estimated, and the waveform of the cancel wave Wc is based on the estimated delay time and the estimated waveform. May be determined.
Alternatively, a configuration in which a cancel wave Wc having a preset uniform phase and waveform is transmitted is also a preferred embodiment of the present invention. In this case, the waveform adjustment step has high importance.

(6) In the above embodiment, the case where the fluid identification device 1 includes the waveform adjustment unit 26 has been described as an example. However, the embodiment of the present invention is not limited to this. That is, for example, when the canceling probe 18 can transmit the cancellation wave Wc that can completely cancel the in-body propagation wave Wb from the beginning, the waveform adjustment step is not provided and the waveform adjustment step is performed. It is also one of preferred embodiments of the present invention that the configuration is not executed.

(7) In the above embodiment, the case where the four probes 12, 14, 18a, and 18b are equally distributed in the circumferential direction at the same axial position of the tubular member P has been described as an example. . However, the embodiment of the present invention is not limited to this. That is, it is preferable that at least two canceling probes 18a and 18b are arranged in plane symmetry with respect to the virtual plane Z, and the two canceling probes 18a and 18b are suitable for the transmitting probe 12. It is also one of preferred embodiments of the present invention to have a configuration in which it is arranged at a position close to one of the receiving probe 14 instead of an intermediate point. Alternatively, the two canceling probes 18a and 18b may be arranged at positions that are not plane-symmetric with respect to the virtual plane Z.

(8) In the above embodiment, the case where the fluid identification device 1 is applied to a gas type identification device for determining the type of the gas G present inside the tubular member P has been described as an example. However, the embodiment of the present invention is not limited to this. That is, for example, a liquid such as water, alcohol, oil, or the like can also be a determination target of the fluid type by the fluid identification device 1.

(9) Regarding other configurations as well, the embodiments disclosed herein are illustrative in all respects, and embodiments of the present invention are not limited thereto. In other words, configurations that are not described in the claims of the present application can be modified as appropriate without departing from the object of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used for a fluid identification device and a fluid identification method for identifying the type of fluid existing inside a tubular member.

DESCRIPTION OF SYMBOLS 1 Fluid identification device 12 Transmitting probe 14 Receiving probe 16 Transmission / reception probe 18 Canceling probe 24 Sound velocity calculation unit 25 Fluid determination unit 26 Waveform adjustment unit 30 Recording device 32 Arrival time data 33 Waveform data P Tubular member L Axis G Gas (fluid)
Wt Transmission propagation wave Wb Body propagation wave Wc Cancellation wave Ws Composite wave ΔT Time difference V Sound speed Z Virtual plane

Claims (5)

A transmission step of transmitting ultrasonic waves from a transmission probe disposed on the outer peripheral surface of the tubular member;
Of the ultrasonic waves transmitted from the transmission probe, the transmission wave transmitted through the tubular member and propagated in the tube by the reception probe disposed on the outer peripheral surface of the tubular member, and the transmission A reception step of receiving a propagation wave in the main body that propagates in the main body of the tubular member among the ultrasonic waves transmitted from the probe;
A cancel wave transmission that transmits a cancel wave that cancels the propagation wave in the main body using a cancel probe disposed on the outer peripheral surface of the tubular member separately from the transmission probe and the reception probe. Steps,
In the reception step, at least the transmission propagation wave is received by the reception probe, and the main body according to the reception waveform of the ultrasonic wave received by the reception probe for a predetermined period before the time point A waveform adjustment step of adjusting at least one of the phase, amplitude, and frequency of the cancellation wave so that the amplitude of the combined wave of the inner propagation wave and the cancellation wave is smaller than the transmitted propagation wave as a whole;
The propagation speed of the ultrasonic wave inside the tubular member is calculated based on the time difference from when the ultrasonic wave is transmitted by the transmitting probe to when the transmitted propagation wave is received by the receiving probe. A sound speed calculation step;
A fluid determination step of determining the type of fluid present in the tubular member based on the propagation velocity calculated in the sound speed calculation step ,
In a state where the cancellation wave adjusted in the waveform adjustment step is transmitted from the canceling probe, the transmission probe receives the transmitted propagation wave, and the sound velocity calculation step and the fluid determination step are performed. Fluid identification method to be executed . A transmitting probe that is disposed on the outer peripheral surface of the tubular member and transmits ultrasonic waves;
Of the ultrasonic waves transmitted from the transmission probe, transmitted through the tubular member and propagating through the tube, and transmitted from the transmission probe, arranged on the outer peripheral surface of the tubular member A receiving probe for receiving a propagating wave in the main body that propagates in the main body of the tubular member of the ultrasonic wave; and
A canceling probe that is arranged on the outer peripheral surface of the tubular member separately from the transmitting probe and the receiving probe, and transmits a canceling wave that cancels the propagation wave in the main body,
For at least a predetermined period before the time when the transmitted propagation wave is received by the receiving probe, according to the received waveform of the ultrasonic wave received by the receiving probe, A waveform adjustment unit that adjusts at least one of the phase, amplitude, and frequency of the cancellation wave so that the amplitude of the combined wave with the cancellation wave is smaller than the transmitted propagation wave as a whole;
In a state where the cancel wave adjusted by the waveform adjusting unit is transmitted from the canceling probe, the transmission probe receives the transmitted propagation wave, and the transmitting probe transmits ultrasonic waves. A sound speed calculation unit that calculates a propagation speed of ultrasonic waves inside the tubular member based on a time difference from when the transmitted propagation wave is received by the reception probe after the transmission of
A fluid identification device, comprising: a fluid determination unit that determines a type of fluid existing inside the tubular member based on the propagation velocity calculated by the sound velocity calculation unit. The arrival time data indicating the arrival time until the propagation wave in the main body from the transmission probe reaches the canceling probe, and the waveform data indicating the waveform of the propagation wave in the main body, the tubular A recording device prerecorded according to at least one of the material of the member, the pipe diameter, and the pipe thickness;
The canceling probe transmits, as the canceling wave, an antiphase wave having a waveform which is calculated based on the arrival time data and the waveform data and has a phase opposite to the propagation wave in the main body. Item 3. The fluid identification device according to Item 2 . The fluid identification according to claim 2 or 3 , comprising two canceling probes arranged in plane symmetry with respect to a virtual plane on which the axis of the tubular member and the receiving probe are arranged. apparatus. 5. The fluid identification according to claim 4 , wherein the transmitting probe and the receiving probe that are individually provided are opposed to each other so as to sandwich the tubular member in the radial direction on the virtual plane. apparatus.

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