JP7300916B2 - Clamp-on type ultrasonic flowmeter and clamp-on type ultrasonic flow measurement method - Google Patents

Description

The present invention relates to a clamp-on ultrasonic flowmeter and a clamp-on ultrasonic flow measurement method.

2. Description of the Related Art Conventionally, there has been known a flow rate measuring device including an ultrasonic flowmeter having an upstream transducer and a downstream transducer, and a heating device (see Patent Document 1, for example).
In the flow measuring device described in Patent Document 1, the refrigerant after being liquefied in the vapor compression refrigeration cycle flows through the piping. Also, a cooling device is positioned upstream of the ultrasonic flow meter having an upstream transducer and a downstream transducer, and a heating device is positioned downstream of the ultrasonic flow meter having an upstream transducer and a downstream transducer. It is
Specifically, in the flow measuring device described in Patent Document 1, the gas-liquid two-phase refrigerant in the pipe is cooled by the cooling device to be in a liquid phase state (full liquid state). Next, an ultrasonic flowmeter measures the flow rate of the refrigerant in the liquid phase state (full liquid state) in the pipe. Next, the refrigerant in the liquid phase state (full liquid state) in the pipe is heated by the heating device to return to the gas-liquid two-phase state, and is used in the vapor compression refrigeration cycle.
That is, in the flow measuring device described in Patent Document 1, the ultrasonic flowmeter measures the flow rate of the refrigerant that has been cooled and liquefied by the cooling device (the flow rate of the refrigerant in a liquid phase state (full liquid state)).

By the way, with the technique described in Patent Document 1, for example, even if it is cooled, it is not possible to measure the flow rate of wet steam having a degree of wetness that does not cause a liquid-filled state in which the pipe is filled with liquid.
In addition, a clamp-on type ultrasonic flowmeter that measures the flow rate of steam flowing in a pipe has just been developed, and this clamp-on type ultrasonic flowmeter can measure the flow rate of wet steam with any range of wetness. Not sure.

JP 2008-281255 A

In intensive research, the present inventors have found that when the fluid flowing in the flow path of the piping is dry steam, the flow path of the piping is measured by a clamp-on ultrasonic flowmeter having an upstream transducer and a downstream transducer. It was found that the flow rate of the fluid (dry steam) flowing inside can be measured.
In addition, the inventors of the present invention have found in their intensive research that when the fluid flowing in the flow path of the piping is wet steam and the flow mode of the fluid flowing in the flow path of the piping is a laminar flow or a wavy flow, Secondly, it was found that a clamp-on type ultrasonic flowmeter having an upstream transducer and a downstream transducer can measure the flow rate of a fluid (wet steam) flowing in a pipe flow path.
Furthermore, in intensive research, the present inventors have found that when the fluid flowing in the flow path of the piping is wet steam and the flow mode of the fluid flowing in the flow path of the piping is an annular spray flow , Although it may not be possible to measure the flow rate of the fluid (wet steam) flowing in the pipe flow path with a clamp-on type ultrasonic flowmeter having an upstream transducer and a downstream transducer, the wet steam is heated With dry steam, we have found that a clamp-on ultrasonic flowmeter having an upstream transducer and a downstream transducer can measure the flow rate of a fluid flowing through a pipe flow path.
In other words, an object of the present invention is to provide a clamp-on ultrasonic flowmeter and a clamp-on ultrasonic flow measurement method capable of measuring the flow rate of wet steam flowing through the flow path of a pipe.

One aspect of the present invention is a clamp-on type ultrasonic flowmeter that measures the flow rate of wet steam flowing in a flow path of a pipe, wherein a first transmitter and a first receiver that transmit a first ultrasonic wave are a first ultrasonic transducer, and a second transmitter and a second receiver for transmitting a second ultrasonic wave, and are arranged downstream of the first ultrasonic transducer in the flow of the wet steam. A second ultrasonic transducer, a first reception signal output by the second receiving unit that receives the first ultrasonic wave transmitted through the flow channel, and the second ultrasonic wave transmitted through the flow channel By calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the received second reception signal output by the first receiving unit, a calculation unit for calculating the flow rate of the wet steam, and a calculation unit arranged upstream of the flow of the wet steam relative to the first ultrasonic transducer and the second ultrasonic transducer to heat the wet steam flowing in the flow path. and a heater control section for controlling the heater, wherein the calculation section controls the waveform of the first reception signal output by the second reception section and the waveform of the first reception signal output by the first reception section. The heater control unit calculates the propagation time difference based on the position of the correlation peak obtained by calculating the cross-correlation with respect to the waveform of the second received signal obtained by the calculation unit. When the peak value is less than or equal to the first threshold, the heater is turned on from the off state, and when the correlation peak value obtained by the computing unit is greater than the first threshold, the heater is maintained in the off state. It is a clamp-on type ultrasonic flowmeter.

One aspect of the present invention is a clamp-on type ultrasonic flowmeter that measures the flow rate of wet steam flowing in a flow path of a pipe, wherein a first transmitter and a first receiver that transmit a first ultrasonic wave are a first ultrasonic transducer, and a second transmitter and a second receiver for transmitting a second ultrasonic wave, and are arranged downstream of the first ultrasonic transducer in the flow of the wet steam. A second ultrasonic transducer, a first reception signal output by the second receiving unit that receives the first ultrasonic wave transmitted through the flow channel, and the second ultrasonic wave transmitted through the flow channel By calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the received second reception signal output by the first receiving unit, a calculation unit for calculating the flow rate of the wet steam, and a calculation unit arranged upstream of the flow of the wet steam relative to the first ultrasonic transducer and the second ultrasonic transducer to heat the wet steam flowing in the flow path. and a heater control section for controlling the heater, wherein the heater control section controls the signal/noise ratio of the first reception signal output by the second reception section and the first When at least one of the signal/noise ratio of the second reception signal output by the reception unit is equal to or less than the second threshold, the heater is turned on from the off state, and the second reception signal output by the second reception unit is turned on. a clamp-on type that maintains the heater in an off state when the signal/noise ratio of one received signal and the signal/noise ratio of the second received signal output by the first receiver are greater than the second threshold; It is an ultrasonic flow meter.

One aspect of the present invention is a clamp-on type ultrasonic flowmeter that measures the flow rate of wet steam flowing in a flow path of a pipe, wherein a first transmitter and a first receiver that transmit a first ultrasonic wave are a first ultrasonic transducer, and a second transmitter and a second receiver for transmitting a second ultrasonic wave, and are arranged downstream of the first ultrasonic transducer in the flow of the wet steam. A second ultrasonic transducer, a first reception signal output by the second receiving unit that receives the first ultrasonic wave transmitted through the flow channel, and the second ultrasonic wave transmitted through the flow channel By calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the received second reception signal output by the first receiving unit, a calculation unit for calculating the flow rate of the wet steam, and a calculation unit arranged upstream of the flow of the wet steam relative to the first ultrasonic transducer and the second ultrasonic transducer to heat the wet steam flowing in the flow path. and a heater control section for controlling the heater, wherein the heater control section controls the aerial propagation wave transmitted from the first transmission section and transmitted through the flow path. From the signal containing noise output by the second receiving unit that receives the first ultrasonic wave and the in-pipe propagated wave transmitted from the first transmitting unit and propagated in the wall of the pipe, the first ultrasonic wave If the first received signal that is the received signal of cannot be identified, or the second ultrasonic wave as an airborne wave transmitted from the second transmission unit and transmitted through the flow path, and the second transmission The second received signal, which is the received signal of the second ultrasonic wave, is identified from the noise-containing signal output by the first receiving unit that received the in-pipe propagation wave transmitted from the unit and transmitted through the wall. If it is not possible, the heater is turned on from the off state, and the first ultrasonic wave as an airborne wave transmitted from the first transmission unit and transmitted through the flow path is transmitted from the first transmission unit. The first received signal, which is the received signal of the first ultrasonic wave, is identified from the noise-containing signal output by the second receiving unit that has received the in-pipe propagating wave propagated in the wall of the pipe. When possible, the second ultrasonic wave as an airborne wave transmitted from the second transmitter and transmitted through the flow path, and the second ultrasonic wave transmitted from the second transmitter and transmitted through the wall The heater is maintained in an OFF state when the second received signal, which is the received signal of the second ultrasonic wave, can be identified from the noise-containing signal output by the first receiving unit that has received the in-pipe propagation wave. It is a clamp-on type ultrasonic flowmeter.

One aspect of the present invention is a clamp-on type ultrasonic flowmeter that measures the flow rate of wet steam flowing in a flow path of a pipe, wherein a first transmitter and a first receiver that transmit a first ultrasonic wave are a first ultrasonic transducer, and a second transmitter and a second receiver for transmitting a second ultrasonic wave, and are arranged downstream of the first ultrasonic transducer in the flow of the wet steam. A second ultrasonic transducer, a first reception signal output by the second receiving unit that receives the first ultrasonic wave transmitted through the flow channel, and the second ultrasonic wave transmitted through the flow channel By calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the received second reception signal output by the first receiving unit, a calculation unit for calculating the flow rate of the wet steam, and a calculation unit arranged upstream of the flow of the wet steam relative to the first ultrasonic transducer and the second ultrasonic transducer to heat the wet steam flowing in the flow path. and a heater controller for controlling the heater, and at least a first temperature sensor and a second temperature sensor, wherein the first ultrasonic transducer and the second ultrasonic transducer are arranged. The pipe extends horizontally at a position where the pipe extends horizontally, the first temperature sensor and the second temperature sensor are arranged at different positions in the vertical direction of the pipe extending in the horizontal direction, and the heater control unit is and turning on the heater when the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are equal to the temperature detected by the first temperature sensor and the second temperature A clamp-on ultrasonic flowmeter that turns off the heater when the temperature is different from that detected by a sensor.

In the clamp-on ultrasonic flowmeter according to one aspect of the present invention, during a period in which the heater is maintained in an ON state, the computing unit calculates the flow rate of the dry steam corresponding to the flow rate of the wet steam. Later, the heater control section may switch the heater from the ON state to the OFF state.

In the clamp-on type ultrasonic flowmeter according to one aspect of the present invention, the heater control unit switches the heater from the ON state when a preset time elapses after switching the heater from the OFF state to the ON state. It may be switched to the OFF state.

The clamp-on ultrasonic flowmeter of one aspect of the present invention further comprises at least a first temperature sensor and a second temperature sensor, and at a position where the first ultrasonic transducer and the second ultrasonic transducer are arranged The pipe extends in the horizontal direction, the first temperature sensor and the second temperature sensor are arranged at different positions in the vertical direction of the pipe extending in the horizontal direction. When the temperature detected by the temperature sensor and the temperature detected by the second temperature sensor are equal, the heater is turned on, and the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are turned on. The heater may be turned off when the temperature is different from the temperature at which the heater is applied.

The clamp-on type ultrasonic flowmeter of one aspect of the present invention further includes a temperature sensor, and the pipe extends horizontally at positions where the first ultrasonic transducer and the second ultrasonic transducer are arranged. , the temperature sensor is arranged below the pipe extending in the horizontal direction, and when the temperature detected by the temperature sensor is less than the saturated steam equivalent temperature, the heater is turned on, and the temperature sensor detects The heater may be turned off when the detected temperature is equal to or higher than the saturated steam equivalent temperature.

In the clamp-on type ultrasonic flowmeter of one aspect of the present invention, the pipe extends horizontally at a position where the first ultrasonic transducer, the second ultrasonic transducer and the heater are arranged, and the heater may be arranged below the central axis of the pipe.

One aspect of the present invention is a first ultrasonic transducer having a first transmitter and a first receiver that transmit a first ultrasonic wave, and a second transmitter and a second receiver that transmit a second ultrasonic wave. a second ultrasonic transducer arranged downstream of the first ultrasonic transducer in the flow of the wet steam flowing in the flow path of the pipe, the first ultrasonic transducer and the second ultrasonic wave A clamp-on type ultrasonic flow measurement method for measuring the flow rate of the wet steam by using a heater arranged upstream of the flow of the wet steam from the transducer, wherein Waveform of a first reception signal output by the second reception unit that received the first ultrasonic wave and a second reception signal output by the first reception unit that received the second ultrasonic wave transmitted through the flow path a first step of calculating a correlation peak obtained by calculating cross-correlation with respect to the waveform of the received signal; and when the value of the correlation peak obtained in the first step is equal to or less than a first threshold, a second step of turning the heater from the off state to the on state and maintaining the heater in the off state when the value of the correlation peak obtained in the first step is greater than the first threshold; a third step of heating the wet steam flowing in the flow path to dry steam by the heater when it is determined to switch from the off state to the on state; and the first reception signal and the second reception. a fourth step of calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the correlation peak with the signal; and and a fifth step of calculating the flow rate of the wet steam based on the propagation time difference.
One aspect of the present invention is a first ultrasonic transducer having a first transmitter and a first receiver that transmit a first ultrasonic wave, and a second transmitter and a second receiver that transmit a second ultrasonic wave. a second ultrasonic transducer arranged downstream of the first ultrasonic transducer in the flow of the wet steam flowing in the flow path of the pipe, the first ultrasonic transducer and the second ultrasonic wave A clamp-on type ultrasonic flow measurement method for measuring the flow rate of the wet steam by using a heater arranged upstream of the flow of the wet steam from the transducer, wherein A signal/noise ratio of the first received signal output by the second receiving unit that received the first ultrasonic wave and output by the first receiving unit that received the second ultrasonic wave transmitted through the flow path When at least one of the signal/noise ratio of the second received signal is equal to or less than a second threshold, the heater is turned on from the off state, and the signal/noise ratio of the first received signal output by the second receiving unit a first step of keeping the heater off when the noise ratio and the signal/noise ratio of the second received signal output by the first receiver are greater than the second threshold; a second step of heating the wet steam flowing in the flow path to dry steam by the heater when it is determined to switch the heater from the off state to the on state; the first reception signal; a third step of calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the second received signal; and and a fourth step of calculating the flow rate of the wet steam based on the propagation time difference.
One aspect of the present invention is a first ultrasonic transducer having a first transmitter and a first receiver that transmit a first ultrasonic wave, and a second transmitter and a second receiver that transmit a second ultrasonic wave. a second ultrasonic transducer arranged downstream of the first ultrasonic transducer in the flow of the wet steam flowing in the flow path of the pipe, the first ultrasonic transducer and the second ultrasonic wave A clamp-on ultrasonic flow measurement method for measuring the flow rate of the wet steam by using a heater arranged upstream of the flow of the wet steam from the transducer, wherein the first transmitter transmits and the second reception that receives the first ultrasonic wave as an airborne wave transmitted through the flow path and the in-pipe propagated wave transmitted from the first transmission unit and propagated in the wall of the pipe. If the first reception signal, which is the reception signal of the first ultrasonic wave, cannot be identified from the signal containing noise output by the unit, or the air transmitted from the second transmission unit and transmitted through the flow path From the signal containing noise output by the first receiving unit that receives the second ultrasonic wave as a propagating wave and the in-pipe propagating wave transmitted from the second transmitting unit and transmitted through the wall, the 2 When the second received signal, which is the received signal of the ultrasonic waves, cannot be identified, the heater is turned on from the off state, and the aerial propagation wave transmitted from the first transmitter and transmitted through the flow path From the signal including noise output by the second receiving unit that receives the first ultrasonic wave and the in-pipe propagated wave transmitted from the first transmitting unit and propagated in the wall of the pipe, the first When the first received signal, which is an ultrasonic received signal, can be identified, the second ultrasonic wave as an airborne wave transmitted from the second transmission unit and transmitted through the flow path; The second reception, which is the reception signal of the second ultrasonic wave, from the signal containing noise output by the first reception unit that received the in-pipe propagation wave transmitted from the second transmission unit and transmitted through the wall. a first step of maintaining the heater in an off state if a signal can be identified; a second step of heating wet steam to dry steam by the heater; and a propagation time of the first ultrasonic wave and the second ultrasonic wave based on the first received signal and the second received signal. and a fourth step of calculating the flow rate of the wet steam based on the propagation time difference calculated in the third step. An ultrasonic flow measurement method.
In one aspect of the present invention, a first ultrasonic transducer having a first transmitting unit and a first receiving unit for transmitting a first ultrasonic wave arranged in a pipe extending in a horizontal direction, and a second ultrasonic wave. A second ultrasonic transducer having a second transmitting unit and a second receiving unit for transmitting, and arranged in the pipe downstream of the flow of the wet steam flowing in the flow path of the pipe from the first ultrasonic transducer. using an acoustic transducer, a heater positioned upstream of the wet steam flow relative to the first and second ultrasonic transducers, and at least a first temperature sensor and a second temperature sensor. In the clamp-on type ultrasonic flow measurement method for measuring the flow rate of the wet steam, when the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are equal, the a first step of turning on a heater and turning off the heater when the temperature detected by the first temperature sensor is different from the temperature detected by the second temperature sensor; a second step of heating the wet steam flowing in the flow path to dry steam by the heater when it is determined to switch the heater from the off state to the on state; A first reception signal output by the second reception unit that has received the first ultrasonic wave, and a second reception output by the first reception unit that has received the second ultrasonic wave transmitted through the flow path a third step of calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the signal; and the propagation time difference calculated in the third step. and a fourth step of calculating the flow rate of the wet steam based on the clamp-on type ultrasonic flow measurement method.

ADVANTAGE OF THE INVENTION According to this invention, the clamp-on-type ultrasonic flowmeter and clamp-on-type ultrasonic flow-measuring method which can measure the flow volume of the wet steam which flows through the inside of the flow path of piping can be provided.

It is a figure which shows an example of the functional block of the clamp-on type ultrasonic flowmeter of 1st Embodiment. It is a figure which shows an example of a structure of the clamp-on type ultrasonic flowmeter of 1st Embodiment. FIG. 4 is a diagram showing another example of the configuration of the clamp-on type ultrasonic flowmeter of the first embodiment; It is a figure for demonstrating the 2nd example of the clamp-on type ultrasonic flowmeter of 1st Embodiment. 4 is a flow chart for explaining processing executed in each example of the clamp-on type ultrasonic flowmeter of the first embodiment; It is a figure which shows the functional block of the 1st example of the clamp-on type ultrasonic flowmeter of 2nd Embodiment. It is a figure which shows the structure of the 1st example of the clamp-on type ultrasonic flowmeter of 2nd Embodiment. FIG. 10 is a flow chart for explaining processing executed in the first example of the clamp-on type ultrasonic flowmeter of the second embodiment; FIG. FIG. 10 is a diagram showing functional blocks of a second example of the clamp-on type ultrasonic flowmeter of the second embodiment; FIG. 10 is a diagram showing the configuration of a second example of the clamp-on type ultrasonic flowmeter of the second embodiment; FIG. 10 is a flow chart for explaining processing executed in a second example of the clamp-on type ultrasonic flowmeter of the second embodiment; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a clamp-on ultrasonic flowmeter and a clamp-on ultrasonic flow measurement method according to the present invention will be described below with reference to the drawings.

[First embodiment]
FIG. 1 is a diagram showing an example of functional blocks of a clamp-on type ultrasonic flowmeter 1 according to the first embodiment. FIG. 2 is a diagram showing an example of the configuration of the clamp-on type ultrasonic flowmeter 1 of the first embodiment. Specifically, FIG. 2A is a schematic diagram (schematic horizontal sectional view seen from the positive side in the Z-axis direction) of the main part of the clamp-on type ultrasonic flowmeter 1 of the first embodiment. 2(B) is a schematic vertical sectional view of the main part of the clamp-on type ultrasonic flowmeter 1 of the first embodiment as seen from the positive side in the Y-axis direction, and FIG. 2(C) is the first embodiment. 1 is a schematic vertical cross-sectional view of the main part of the clamp-on type ultrasonic flowmeter 1 of FIG. 1 as viewed from the negative side in the X-axis direction.
In the example shown in FIGS. 1 and 2, the clamp-on type ultrasonic flowmeter 1 measures the flow rate of wet steam flowing through the flow path A2 of the pipe A. In the example shown in FIGS. The clamp-on type ultrasonic flowmeter 1 includes a first ultrasonic transducer 11, a second ultrasonic transducer 12, a computing section 13, a heater 14, a heater control section 15, and a transducer control section 16. .

In the example shown in FIGS. 1 and 2, the pipe A extends in the horizontal direction (horizontal direction in FIG. 2(B)) at the position where the first ultrasonic transducer 11, the second ultrasonic transducer 12 and the heater 14 are arranged. extended.
In another example, the pipe A does not have to extend horizontally at the positions where the first ultrasonic transducer 11, the second ultrasonic transducer 12 and the heater 14 are arranged.

In the example shown in FIGS. 1 and 2, the first ultrasonic transducer 11 includes a transmitter 11A and a receiver 11B, and the second ultrasonic transducer 12 includes a transmitter 12A and a receiver 12B. I have. The transmitting section 11A of the first ultrasonic transducer 11 transmits ultrasonic waves, and the receiving section 12B of the second ultrasonic transducer 12 transmits ultrasonic waves from the transmitting section 11A of the first ultrasonic transducer 11 to the flow path A2 of the pipe A. Receives ultrasonic waves that pass through the inside. Specifically, the receiver 12B of the second ultrasonic transducer 12 converts the received ultrasonic waves from the transmitter 11A of the first ultrasonic transducer 11 into a received signal (voltage signal) and outputs the received signal.
The transmitting section 12A of the second ultrasonic transducer 12 transmits ultrasonic waves, and the receiving section 11B of the first ultrasonic transducer 11 transmits ultrasonic waves from the transmitting section 12A of the second ultrasonic transducer 12 to the flow path A2 of the pipe A. Receives ultrasonic waves that pass through the inside. Specifically, the receiver 11B of the first ultrasonic transducer 11 converts the received ultrasonic waves from the transmitter 12A of the second ultrasonic transducer 12 into a received signal (voltage signal) and outputs the received signal.
The second ultrasonic transducer 12 is located downstream of the first ultrasonic transducer 11 (Fig. 2(A) and the right side of FIG. 2(B)).

In the example shown in FIG. 2 , the ultrasonic waves transmitted from the transmitter 11A of the first ultrasonic transducer 11 and transmitted through the flow path A2 of the pipe A do not reflect on the inner surface of the wall A1 of the pipe A. 2 Ultrasonic waves that are received by the receiving unit 12B of the ultrasonic transducer 12 and are transmitted from the transmitting unit 12A of the second ultrasonic transducer 12 and transmitted through the flow path A2 of the pipe A are transmitted through the wall of the pipe A The first ultrasonic transducer 11 and the second ultrasonic transducer 12 are arranged so as to be received by the receiving portion 11B of the first ultrasonic transducer 11 without reflection on the inner surface of the portion A1, and the so-called Z-law fluid flow rate measurement is performed.
In another example, the ultrasonic waves transmitted from the transmission unit 11A of the first ultrasonic transducer 11 and transmitted through the flow path A2 of the pipe A are reflected once on the inner surface of the wall A1 of the pipe A, and then transmitted through the flow path A2 of the pipe A so as to be received by the receiving section 12B of the second ultrasonic transducer 12, and transmitted from the transmitting section 12A of the second ultrasonic transducer 12 through the flow path A2 of the pipe A so that the transmitted ultrasonic wave is reflected once by the inner surface of the wall portion A1 of the pipe A, is transmitted through the flow path A2 of the pipe A, and is received by the receiving portion 11B of the first ultrasonic transducer 11. 1 ultrasonic transducer 11 and the 2nd ultrasonic transducer 12 may be arranged and the flow rate measurement of the fluid of what is called V method may be performed.
In yet another example, the ultrasonic waves transmitted from the transmission unit 11A of the first ultrasonic transducer 11 and transmitted through the flow path A2 of the pipe A are reflected twice on the inner surface of the wall A1 of the pipe A, and then the pipe In the flow path A2 of the pipe A so as to be transmitted through the flow path A2 of A and received by the receiving section 12B of the second ultrasonic transducer 12, and transmitted from the transmitting section 12A of the second ultrasonic transducer 12 After being reflected twice by the inner surface of the wall portion A1 of the pipe A, the ultrasonic wave transmitted through the pipe A passes through the flow path A2 of the pipe A and is received by the receiving portion 11B of the first ultrasonic transducer 11, The first ultrasonic transducer 11 and the second ultrasonic transducer 12 may be arranged to perform so-called N-method fluid flow measurement.

In the example shown in FIG. 2, the damping material is not arranged outside the wall A1 of the pipe A, but in other examples, the damping material is arranged outside the wall A1 of the pipe A. good too.

In the example shown in FIGS. 1 and 2, the calculation unit 13 receives the ultrasonic waves and the like transmitted from the transmission unit 11A of the first ultrasonic transducer 11 and outputs the reception output by the reception unit 12B of the second ultrasonic transducer 12. Based on the signal and the reception signal output by the reception unit 11B of the first ultrasonic transducer 11 that has received the ultrasonic wave or the like transmitted from the transmission unit 12A of the second ultrasonic transducer 12, the flow path A2 of the pipe A Calculations such as calculating the flow rate of the wet steam flowing inside are performed.
The heater 14 heats the wet steam flowing through the flow path A2 of the pipe A to dry steam. The heater 14 is located upstream of the flow of wet steam flowing in the flow path A2 of the pipe A (left side in FIGS. 2A and 2B) relative to the first ultrasonic transducer 11 and the second ultrasonic transducer 12. ).
The heater control unit 15 controls the heater 14 . Specifically, the heater control unit 15 has an ON state in which the heater 14 heats the wet steam flowing through the flow path A2 of the pipe A, and an OFF state in which the heater 14 does not heat the wet steam flowing through the flow path A2 of the pipe A. and control to switch between.
The transducer control unit 16 executes control of the first ultrasonic transducer 11 and control of the second ultrasonic transducer 12 .

In the example shown in FIGS. 1 and 2, in order to calculate the flow rate of wet steam flowing in the flow path A2 of the pipe A, the transmitter 11A of the first ultrasonic transducer 11 transmits ultrasonic waves, and the second ultrasonic waves The receiver 12B of the transducer 12 receives the ultrasonic waves transmitted from the transmitter 11A of the first ultrasonic transducer 11 and outputs a received signal (voltage signal).
Further, the transmitting section 12A of the second ultrasonic transducer 12 also transmits ultrasonic waves, and the receiving section 11B of the first ultrasonic transducer 11 receives the ultrasonic waves transmitted from the transmitting section 12A of the second ultrasonic transducer 12. and outputs the received signal (voltage signal).
That is, the calculation unit 13 receives the ultrasonic wave or the like transmitted from the transmission unit 11A of the first ultrasonic transducer 11 and outputs the reception signal output by the reception unit 12B of the second ultrasonic transducer 12, and the second ultrasonic transducer Based on the reception signal output by the reception unit 11B of the first ultrasonic transducer 11 that has received the ultrasonic wave or the like transmitted from the transmission unit 12A of 12, the flow rate of the wet steam flowing in the flow path A2 of the pipe A is calculated. calculate.
Specifically, in order to calculate the flow rate of the wet steam flowing through the flow path A2 of the pipe A, the calculation unit 13 includes a first reception signal acquisition unit 13A, a second reception signal acquisition unit 13B, and a correlation value calculation unit. 13C, a propagation time difference calculator 13D, and a flow rate calculator 13E.
In the example shown in FIGS. 1 and 2, the calculation unit 13 does not include a flow velocity calculation unit for calculating the flow velocity of the wet steam flowing through the flow path A2 of the pipe A. A calculator may be provided.

The first received signal acquisition unit 13A acquires a received signal output by the receiving unit 12B of the second ultrasonic transducer 12 (that is, the receiving unit 12B of the second ultrasonic transducer 12 receives the transmitting unit 11A of the first ultrasonic transducer 11 Receives ultrasonic waves, etc., transmitted from and converts them into voltage signals).
The second received signal acquisition unit 13B acquires a received signal output by the receiving unit 11B of the first ultrasonic transducer 11 (that is, the receiving unit 11B of the first ultrasonic transducer 11 receives the transmitting unit 12A of the second ultrasonic transducer 12 Receives ultrasonic waves, etc., transmitted from and converts them into voltage signals).

The correlation value calculation unit 13C, for example, by using the method described in JP-A-2013-088322, the reception signal acquired by the first reception signal acquisition unit 13A (by the reception unit 12B of the second ultrasonic transducer 12 Output received signal) and the waveform of the received signal acquired by the second received signal acquisition unit 13B (received signal output by the receiving unit 11B of the first ultrasonic transducer 11). Calculate. That is, the correlation value calculator 13C calculates the correlation between the waveform of the received signal output by the receiver 12B of the second ultrasonic transducer 12 and the waveform of the received signal output by the receiver 11B of the first ultrasonic transducer 11. Calculate the correlation value.

The propagation time difference calculation unit 13D, for example, by using the method described in JP-A-2013-088322, from the cross-correlation value peak (correlation peak) calculated by the correlation value calculation unit 13C, the first ultrasonic transducer 11 transmitted from the transmitter 11A, transmitted through the flow path A2 of the pipe A, and received by the receiver 12B of the second ultrasonic transducer 12, the propagation time of the ultrasonic wave, and the transmitter of the second ultrasonic transducer 12 12A, transmitted through the flow path A2 of the pipe A, and received by the receiver 11B of the first ultrasonic transducer 11, the propagation time difference, which is the difference from the propagation time, is calculated. Specifically, the propagation time difference calculator 13D calculates the propagation time difference based on the position of the correlation peak.

The flow rate calculator 13E calculates the flow rate of the fluid flowing through the flow path A2 of the pipe A based on the propagation time difference calculated by the propagation time difference calculator 13D. Specifically, the flow rate calculation unit 13LE is based on the propagation time difference calculated by the propagation time difference calculation unit 13D, the speed of sound, the inner diameter of the pipe A, the angle θ (see FIG. 2A), a known flow rate calculation formula, etc. The flow rate of wet steam flowing through the flow path A2 of the pipe A is calculated.

As described above, the inventors of the present invention have found in their intensive research that when the fluid flowing in the flow path of the piping is dry steam, a clamp-on ultrasonic flowmeter having an upstream transducer and a downstream transducer , found that the flow rate of the fluid (dry steam) flowing in the flow path of the piping can be measured.
That is, the clamp-on type ultrasonic flowmeter 1 of the first embodiment having the first ultrasonic transducer 11 and the second ultrasonic transducer 12 can be used when the fluid flowing in the flow path A2 of the pipe A is dry steam. , the flow rate of dry steam flowing in the flow path A2 of the pipe A can be measured (that is, the flow rate calculation unit 13E of the calculation unit 13 can calculate the flow rate of the dry steam flowing in the flow path A2 of the pipe A). can be done).

In addition, as described above, the inventors of the present invention have found in their intensive research that when the fluid flowing in the flow path of the piping is wet steam, the flow mode of the fluid flowing in the flow path of the piping is laminar flow or We have found that a clamp-on type ultrasonic flowmeter having an upstream transducer and a downstream transducer can measure the flow rate of a fluid (wet steam) flowing in a pipe flow path in the case of a wavy flow.
That is, in the clamp-on type ultrasonic flowmeter 1 of the first embodiment having the first ultrasonic transducer 11 and the second ultrasonic transducer 12, the fluid flowing in the flow path A2 of the piping A is a laminar flow or a wavy flow. In the case of wet steam, the flow rate of the wet steam flowing through the flow path A2 of the pipe A can be measured (that is, the flow rate calculation unit 13E of the calculation unit 13 can measure the laminar flow flowing through the flow path A2 of the pipe A or the flow rate of wet steam in a wavy flow can be calculated).

Furthermore, as described above, the inventors of the present invention have found in their intensive research that when the fluid flowing in the flow path of the piping is wet steam, the flow pattern of the fluid flowing in the flow path of the piping is an annular spray flow. , the clamp-on ultrasonic flowmeter having an upstream transducer and a downstream transducer may not be able to measure the flow rate of the fluid (wet steam) flowing in the pipe flow path, but the wetness After heating the steam to dry steam, it has been found that a clamp-on ultrasonic flowmeter having an upstream transducer and a downstream transducer can measure the flow rate of a fluid flowing in a pipe flow path.
That is, the clamp-on type ultrasonic flowmeter 1 of the first embodiment having the first ultrasonic transducer 11 and the second ultrasonic transducer 12 measures the flow rate of the wet steam of the annular spray flowing in the flow path A2 of the pipe A. may not be measured.
In such a case, in the example shown in FIGS. 1 and 2, the heater control unit 15 controls the heater 14 to the ON state, and the heater 14 heats the wet steam flowing through the flow path A2 of the pipe A to dry it. make it steam. Further, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the dry steam flowing through the flow path A2 of the pipe A.
That is, in the example shown in FIGS. 1 and 2, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the wet steam flowing through the flow path A2 of the pipe A as the flow rate of the pipe A obtained by heating by the heater 14. Calculate the flow rate of dry steam in A2. In this manner, the clamp-on type ultrasonic flowmeter 1 of the first embodiment can measure the flow rate of wet steam flowing through the flow path A2 of the pipe A.

Specifically, in the first example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, the correlation value calculator 13C of the calculator 13 is is equal to or less than a first threshold value (for example, "0.8"), the heater control unit 15 switches the heater 14 from off to on. Furthermore, during the period in which the heater 14 is maintained in the ON state, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the wet steam flowing through the flow path A2 of the pipe A as the pipe obtained by heating by the heater 14. The flow rate of dry steam in the flow path A2 of A is calculated.
After the flow rate of the dry steam is calculated by the flow rate calculation section 13E of the calculation section 13, the heater control section 15 switches the heater 14 from the ON state to the OFF state.
In another example, the heater control unit 15 may switch the heater 14 from the ON state to the OFF state when a preset time has elapsed after the heater 14 was switched from the OFF state to the ON state.

Further, in the first example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, the value of the correlation peak calculated by the correlation value calculation unit 13C of the calculation unit 13 in the state where the heating by the heater 14 is not performed is If it is greater than the first threshold, the heater control unit 15 keeps the heater 14 off without switching the heater 14 to on. Furthermore, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow path A2 of the pipe A based on the position of the correlation peak calculated by the correlation value calculation unit 13C of the calculation unit 13 while the heater 14 is not heating. Calculate the flow rate of wet steam flowing inside.

As described above, in the example shown in FIGS. 1 and 2, the pipe A extends horizontally (see FIG. 2(A) and left-right direction in FIG. 2(B)).
Furthermore, in the example shown in FIGS. 1 and 2, as shown in FIGS. 2B and 2C, the heater 14 is below the center axis AX of the pipe A 2(C)).

FIG. 3 is a diagram showing another example of the configuration of the clamp-on type ultrasonic flowmeter 1 of the first embodiment. Specifically, FIG. 3A shows another example of a schematic vertical cross-section of the main part of the clamp-on type ultrasonic flowmeter 1 of the first embodiment viewed from the positive side in the Y-axis direction. FIG. 3(B) shows another example of a schematic vertical cross-section of the main part of the clamp-on type ultrasonic flowmeter 1 of the first embodiment viewed from the negative side in the X-axis direction.
In the example shown in FIG. 3, as in the examples shown in FIGS. 1 and 2, the piping A extends in the horizontal direction ( 3A).
Furthermore, in the example shown in FIG. 3, an annular heater 14 is arranged on the outer surface of the wall portion A1 of the pipe A, as shown in FIGS. 3A and 3B.

FIG. 4 is a diagram for explaining a second example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment. Specifically, FIGS. 4A and 4B show flow path A2 of pipe A transmitted from transmitter 11A of first ultrasonic transducer 11 of clamp-on type ultrasonic flowmeter 1 of the first embodiment. The waveform of the reception signal output by the reception unit 12B of the second ultrasonic transducer 12 that received the ultrasonic wave or the like transmitted through the inside, and the flow path A2 of the pipe A transmitted from the transmission unit 12A of the second ultrasonic transducer 12 3 is a diagram showing a waveform of a received signal output by a receiving section 11B of the first ultrasonic transducer 11 that has received an ultrasonic wave or the like that has passed through. FIG.

In the example shown in FIGS. 4A and 4B, the ultrasonic waves received by the receiving section 12B of the second ultrasonic transducer 12 are transmitted from the transmitting section 11A of the first ultrasonic transducer 11 and Not only includes ultrasonic waves as air-propagating waves transmitted through the flow path A2 of A, but also in-pipe propagation transmitted from the transmitter 11A of the first ultrasonic transducer 11 and propagated in the wall A1 of the pipe A Also included is ultrasound as a wave. That is, the received signal output by the receiving unit 12B of the second ultrasonic transducer 12 includes an airborne wave transmitted from the transmitting unit 11A of the first ultrasonic transducer 11 and transmitted through the flow path A2 of the pipe A. is converted into a signal by the receiving section 12B of the second ultrasonic transducer 12 (main signal), and transmitted from the transmitting section 11A of the first ultrasonic transducer 11 and transmitted through the wall portion A1 of the pipe A It also includes a signal (noise) obtained by converting an ultrasonic wave as a propagated in-pipe propagation wave into a signal by the receiving section 12B of the second ultrasonic transducer 12 .
Similarly, in the examples shown in FIGS. 4A and 4B, the ultrasonic waves received by the receiving section 11B of the first ultrasonic transducer 11 are transmitted from the transmitting section 12A of the second ultrasonic transducer 12. Not only includes ultrasonic waves as airborne waves that have been transmitted through the flow path A2 of the pipe A, but also transmitted from the transmitter 12A of the second ultrasonic transducer 12 and propagated through the wall A1 of the pipe A It also includes ultrasonic waves as intrapipe-propagating waves. That is, the received signal output by the receiving unit 11B of the first ultrasonic transducer 11 includes an airborne wave transmitted from the transmitting unit 12A of the second ultrasonic transducer 12 and transmitted through the flow path A2 of the pipe A. is converted into a signal by the receiving unit 11B of the first ultrasonic transducer 11 (main signal) and transmitted from the transmitting unit 12A of the second ultrasonic transducer 12 and transmitted through the wall A1 of the pipe A It also includes a signal (noise) obtained by converting an ultrasonic wave as a propagated in-pipe propagation wave into a signal by the receiving section 11B of the first ultrasonic transducer 11 .

In the example shown in FIG. 4A, an ultrasonic wave as an airborne wave transmitted from the transmission unit 11A of the first ultrasonic transducer 11 and transmitted through the flow path A2 of the pipe A is transmitted to the second ultrasonic transducer 12 A signal (main signal) converted into a signal by the receiving unit 12B of is transmitted from the transmitting unit 11A of the first ultrasonic transducer 11 and propagated in the wall A1 of the pipe A. Ultrasonic waves as pipe propagation waves are This signal is buried in the signal (noise) converted by the receiving section 12B of the second ultrasonic transducer 12 and cannot be identified.
Specifically, the S/N ratio (signal/noise ratio) of the received signal output by the receiving section 12B of the second ultrasonic transducer 12 is equal to or less than the second threshold (for example, "1.5").
Further, in the example shown in FIG. 4A, the ultrasonic wave as an airborne wave transmitted from the transmitting portion 12A of the second ultrasonic transducer 12 and transmitted through the flow path A2 of the pipe A is the first ultrasonic wave. Ultrasonic waves as in-pipe propagated waves that have been converted into signals by the receiving part 11B of the transducer 11 (main signals) are transmitted from the transmitting part 12A of the second ultrasonic transducer 12 and propagated in the wall part A1 of the pipe A However, it is buried in the signal (noise) converted by the receiving section 11B of the first ultrasonic transducer 11, and it is possible to identify this signal output by the receiving section 11B of the first ultrasonic transducer 11. Can not.
Specifically, the S/N ratio of the received signal output by the receiver 11B of the first ultrasonic transducer 11 is equal to or less than the second threshold.

On the other hand, in the example shown in FIG. 4B, the ultrasonic wave as the airborne wave transmitted from the transmission unit 11A of the first ultrasonic transducer 11 and transmitted through the flow path A2 of the pipe A is the second ultrasonic wave Ultrasonic waves as in-pipe propagation waves that have been converted into signals by the receiving part 12B of the transducer 12 (main signals) are transmitted from the transmitting part 11A of the first ultrasonic transducer 11 and propagated in the wall part A1 of the pipe A However, it is not buried in the signal (noise) converted into a signal by the receiving section 12B of the second ultrasonic transducer 12, and the main signal output by the receiving section 12B of the second ultrasonic transducer 12 can be identified. .
Specifically, the S/N ratio of the received signal output by the receiver 12B of the second ultrasonic transducer 12 is greater than the second threshold.
Further, in the example shown in FIG. 4B, the ultrasonic wave as an airborne wave transmitted from the transmitting portion 12A of the second ultrasonic transducer 12 and transmitted through the flow path A2 of the pipe A is the first ultrasonic wave Ultrasonic waves as in-pipe propagated waves that have been converted into signals by the receiving part 11B of the transducer 11 (main signals) are transmitted from the transmitting part 12A of the second ultrasonic transducer 12 and propagated in the wall part A1 of the pipe A However, it is not buried in the signal (noise) converted into a signal by the receiving section 11B of the first ultrasonic transducer 11, and the main signal output by the receiving section 11B of the first ultrasonic transducer 11 can be identified. .
Specifically, the S/N ratio of the received signal output by the receiver 11B of the first ultrasonic transducer 11 is greater than the second threshold.

In the second example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, as in the example shown in FIG. When at least one of the N ratio and the S/N ratio of the reception signal output by the reception unit 11B of the first ultrasonic transducer 11 is equal to or less than the second threshold, the heater control unit 15 turns the heater 14 off. to the on state. Furthermore, during the period in which the heater 14 is maintained in the ON state, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the wet steam flowing through the flow path A2 of the pipe A as the pipe obtained by heating by the heater 14. The flow rate of dry steam in the flow path A2 of A is calculated.
After the flow rate of the dry steam is calculated by the flow rate calculation section 13E of the calculation section 13, the heater control section 15 switches the heater 14 from the ON state to the OFF state.
In another example, the heater control unit 15 may switch the heater 14 from the ON state to the OFF state when a preset time has elapsed after the heater 14 was switched from the OFF state to the ON state.

Further, in the second example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, as in the example shown in FIG. When the S/N ratio and the S/N ratio of the reception signal output by the reception unit 11B of the first ultrasonic transducer 11 are larger than the second threshold, the heater control unit 15 switches the heater 14 to the ON state. without holding the heater 14 in the off state. Furthermore, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow path A2 of the pipe A based on the position of the correlation peak calculated by the correlation value calculation unit 13C of the calculation unit 13 while the heater 14 is not heating. Calculate the flow rate of wet steam flowing inside.

In the third example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, as in the example shown in FIG. An ultrasonic wave transmitted through A2 as an airborne wave, and an ultrasonic wave transmitted from the transmitter 11A of the first ultrasonic transducer 11 and propagated in the wall portion A1 of the pipe A as an in-pipe propagated wave were received. If the main signal cannot be identified from the signal containing the main signal and noise output by the receiving unit 12B of the second ultrasonic transducer 12, or if the main signal is transmitted from the transmitting unit 12A of the second ultrasonic transducer 12 and the pipe A An ultrasonic wave transmitted through the flow path A2 as an airborne wave and an ultrasonic wave transmitted from the transmitter 12A of the second ultrasonic transducer 12 and propagated through the wall A1 of the pipe A as an in-pipe propagated wave When the main signal cannot be identified from the received signal including the main signal output by the receiving unit 11B of the first ultrasonic transducer 11 and noise, the heater control unit 15 switches the heater 14 from the off state to the on state. . Furthermore, during the period in which the heater 14 is maintained in the ON state, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the wet steam flowing through the flow path A2 of the pipe A as the pipe obtained by heating by the heater 14. The flow rate of dry steam in the flow path A2 of A is calculated.
After the flow rate of the dry steam is calculated by the flow rate calculation section 13E of the calculation section 13, the heater control section 15 switches the heater 14 from the ON state to the OFF state.
In another example, the heater control unit 15 may switch the heater 14 from the ON state to the OFF state when a preset time has elapsed after the heater 14 was switched from the OFF state to the ON state.

Further, in the third example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, as in the example shown in FIG. An ultrasonic wave transmitted through the flow path A2 as an airborne wave and an ultrasonic wave transmitted from the transmitter 11A of the first ultrasonic transducer 11 and propagated through the wall A1 of the pipe A as an in-pipe propagated wave When the main signal can be identified from the received main signal output by the receiving unit 12B of the second ultrasonic transducer 12 and a signal containing noise, the main signal is transmitted from the transmitting unit 12A of the second ultrasonic transducer 12 An ultrasonic wave as an airborne wave transmitted through the flow path A2 of the pipe A and an ultrasonic wave transmitted from the transmitter 12A of the second ultrasonic transducer 12 and propagated in the wall portion A1 of the pipe A as an in-pipe propagated wave When the main signal can be identified from the signal including noise and the main signal output by the receiving unit 11B of the first ultrasonic transducer 11 that has received the sound waves, the heater control unit 15 switches the heater 14 to the ON state. without holding the heater 14 in the off state. Furthermore, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow path A2 of the pipe A based on the position of the correlation peak calculated by the correlation value calculation unit 13C of the calculation unit 13 while the heater 14 is not heating. Calculate the flow rate of wet steam flowing inside.

FIG. 5 is a flow chart for explaining the processing executed in each example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment.
In the example shown in FIG. 5, in step S10, for example, the heater control unit 15 determines whether it is necessary to switch the heater 14 from the OFF state to the ON state. If it is not necessary to switch the heater 14 from the OFF state to the ON state, the process proceeds to step S11A. On the other hand, if it is necessary to switch the heater 14 from the OFF state to the ON state, the process proceeds to step S11B.
As described above, in the first example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, when the correlation peak value calculated by the correlation value calculator 13C of the calculator 13 is equal to or less than the first threshold, For example, the heater control unit 15 determines that it is necessary to switch the heater 14 from an off state to an on state. On the other hand, when the value of the correlation peak calculated by the correlation value calculation unit 13C of the calculation unit 13 is larger than the first threshold value, the heater control unit 15, for example, determines that it is not necessary to switch the heater 14 from the OFF state to the ON state. judge.
Further, as described above, in the second example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, the S/N ratio of the received signal output by the receiving section 12B of the second ultrasonic transducer 12, and For example, when at least one of the S/N ratios of the reception signals output by the reception unit 11B of the first ultrasonic transducer 11 is equal to or less than the second threshold, the heater control unit 15 turns the heater 14 from the off state to the on state. Decide that you need to switch. On the other hand, the S/N ratio of the received signal output by the receiving section 12B of the second ultrasonic transducer 12 and the S/N ratio of the received signal output by the receiving section 11B of the first ultrasonic transducer 11 are the second If it is larger than the threshold, for example, the heater control unit 15 determines that it is not necessary to switch the heater 14 from off to on.

Further, as described above, in the third example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, the A second ultrasonic transducer that receives an ultrasonic wave as an airborne wave and an ultrasonic wave as an in-pipe-propagating wave that is transmitted from the transmitter 11A of the first ultrasonic transducer 11 and propagates in the wall portion A1 of the pipe A. If the main signal cannot be identified from the signal containing the main signal and noise output by the receiving unit 12B of 12, or if the main signal is transmitted from the transmitting unit 12A of the second ultrasonic transducer 12 and is transmitted through the flow path A2 of the pipe A A first ultrasonic wave that receives an ultrasonic wave as a transmitted airborne wave and an ultrasonic wave that is transmitted from the transmission unit 12A of the second ultrasonic transducer 12 and propagated in the wall portion A1 of the pipe A as an in-pipe propagated wave. When the main signal cannot be identified from the signal including the main signal and the noise output by the receiving unit 11B of the acoustic wave transducer 11, for example, the heater control unit 15 determines that the heater 14 needs to be switched from the off state to the on state. judge. On the other hand, an ultrasonic wave as an airborne wave transmitted from the transmitting portion 11A of the first ultrasonic transducer 11 and transmitted through the flow path A2 of the pipe A and transmitted from the transmitting portion 11A of the first ultrasonic transducer 11 The main signal can be identified from the signal including noise and the main signal output by the receiving section 12B of the second ultrasonic transducer 12 that has received the ultrasonic wave as the in-pipe propagating wave propagated in the wall portion A1 of the pipe A. In the case, the ultrasonic wave as an airborne wave transmitted from the transmission unit 12A of the second ultrasonic transducer 12 and transmitted through the flow path A2 of the pipe A, and the transmission unit 12A of the second ultrasonic transducer 12 From the signal including the noise and the main signal output by the receiving unit 11B of the first ultrasonic transducer 11 that received the ultrasonic wave as the in-pipe propagation wave that was transmitted and propagated in the wall A1 of the pipe A, the main signal can be identified, for example, the heater control unit 15 determines that there is no need to switch the heater 14 from the off state to the on state.

In step S11A, the heater control unit 15 keeps the heater 14 off.
Next, in step S12A, during the period in which the heater 14 is maintained in the OFF state, the correlation value calculation unit 13C of the calculation unit 13 determines the waveform of the reception signal output by the reception unit 12B of the second ultrasonic transducer 12 and the , the cross-correlation value with the waveform of the received signal output by the receiving section 11B of the first ultrasonic transducer 11 is calculated.
Next, in step S13A, the propagation time difference calculator 13D of the calculator 13 calculates the propagation time difference based on the position of the correlation peak calculated by the correlation value calculator 13C of the calculator 13 in step S12A.
Next, in step S14A, the flow rate calculation unit 13E of the calculation unit 13 calculates the wet steam flowing through the flow path A2 of the pipe A based on the propagation time difference calculated by the propagation time difference calculation unit 13D of the calculation unit 13 in step S13A. Calculate the flow rate of

In step S11B, the heater control unit 15 switches the heater 14 from off to on.
Next, in step S12B, while the heater 14 is maintained in the ON state, the correlation value calculation unit 13C of the calculation unit 13 calculates the waveform of the reception signal output by the reception unit 12B of the second ultrasonic transducer 12 and the , the cross-correlation value with the waveform of the received signal output by the receiving section 11B of the first ultrasonic transducer 11 is calculated.
Next, in step S13B, the propagation time difference calculator 13D of the calculator 13 calculates the propagation time difference based on the position of the correlation peak calculated by the correlation value calculator 13C of the calculator 13 in step S12B.
Next, in step S14B, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the pipe A obtained by heating by the heater 14 based on the propagation time difference calculated by the propagation time difference calculation unit 13D of the calculation unit 13 in step S13B. The flow rate of dry steam in the flow path A2 is calculated as the flow rate of wet steam flowing in the flow path A2 of the pipe A.
Next, in step S15, the heater control unit 15 switches the heater 14 from ON to OFF.

[Second embodiment]
A second embodiment of the clamp-on ultrasonic flowmeter and the clamp-on ultrasonic flow measurement method of the present invention will be described below.
The clamp-on type ultrasonic flowmeter 1 of the second embodiment is configured in the same manner as the clamp-on type ultrasonic flowmeter 1 of the above-described first embodiment, except for points described later. Therefore, according to the clamp-on type ultrasonic flowmeter 1 of the second embodiment, the effects similar to those of the clamp-on type ultrasonic flowmeter 1 of the above-described first embodiment can be obtained except for the points described later.

FIG. 6 is a diagram showing functional blocks of a first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment. FIG. 7 is a diagram showing the configuration of a first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment. Specifically, FIG. 7(A) is a schematic view of the main part of the first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment (schematic horizontal sectional view seen from the positive side in the Z-axis direction). 7B is a schematic vertical cross-sectional view of the main part of the first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment as seen from the positive side in the Y-axis direction, and FIG. (C) is a schematic vertical cross-sectional view of the main part of the first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, viewed from the minus side in the X-axis direction.
In the examples shown in FIGS. 6 and 7, the clamp-on ultrasonic flowmeter 1 measures the flow rate of wet steam flowing through the flow path A2 of the pipe A. In the example shown in FIGS. The clamp-on type ultrasonic flowmeter 1 includes a first ultrasonic transducer 11, a second ultrasonic transducer 12, a computing section 13, a heater 14, a heater control section 15, a transducer control section 16, and a temperature sensor 17A. , 17B.

In the example shown in FIGS. 6 and 7, the pipe A extends in the horizontal direction (FIG. 7 (B ) in the horizontal direction). The temperature sensors 17A and 17B are arranged at different positions in the vertical direction (the vertical direction in FIGS. 7(B) and 7(C)) of the pipe A extending in the horizontal direction. Specifically, the temperature sensor 17A is arranged below the center axis AX of the pipe A (below in FIGS. 7(B) and 7(C)), and the temperature sensor 17B 7(B) and 7(C)).

In the example shown in FIGS. 6 and 7, the second ultrasonic transducer 12 is more sensitive to the flow of wet steam flowing in the flow path A2 of the pipe A than the first ultrasonic transducer 11 (FIGS. 7A and 7B). B)) (on the right side in FIGS. 7A and 7B).
The heater 14 is located upstream of the flow of wet steam flowing through the flow path A2 of the pipe A (Fig. 7A and 7 (B)).

As described above, in the first example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, the heater control unit 15 controls the heater based on the correlation value calculated by the correlation value calculation unit 13C of the calculation unit 13 14.
In the second example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, the heater control unit 15 controls the S/N ratio of the reception signal output by the reception unit 12B of the second ultrasonic transducer 12 and the first The heater 14 is controlled based on the S/N ratio of the received signal output by the receiving section 11B of the ultrasonic transducer 11 .
In the third example of the clamp-on type ultrasonic flowmeter 1 of the first embodiment, the heater control unit 15 converts the main signal output from the receiving unit 12B of the second ultrasonic transducer 12 and the signal including noise into the main signal can be identified, and whether or not the main signal can be identified from the main signal output by the receiver 11B of the first ultrasonic transducer 11 and a signal containing noise, the heater 14 is controlled.
On the other hand, in the first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, the heater control unit 15, based on the temperature detected by the temperature sensor 17A and the temperature detected by the temperature sensor 17B, Control the heater 14 .

When the temperature detected by the temperature sensor 17A and the temperature detected by the temperature sensor 17B are equal, it can be estimated that the wet steam of the annular spray flow is flowing through the flow path A2 of the pipe A. Further, when the temperature detected by the temperature sensor 17A and the temperature detected by the temperature sensor 17B are different, it is estimated that wet steam of laminar flow or wave-like flow is flowing in the flow path A2 of the pipe A. can be done.
Therefore, in the first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, when the temperature detected by the temperature sensor 17A and the temperature detected by the temperature sensor 17B are equal, the heater control unit 15 Heater 14 is turned on. As a result, the heater 14 heats the wet steam of the annular spray flowing through the flow path A2 of the pipe A to dry steam. Furthermore, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the wet steam of the annular spray flow flowing in the flow path A2 of the pipe A as the dry steam in the flow path A2 of the pipe A obtained by heating by the heater 14. Calculate the flow rate.
Further, when the temperature detected by the temperature sensor 17A and the temperature detected by the temperature sensor 17B are different, the heater control unit 15 turns the heater 14 off. Further, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the wet steam in the laminar flow or wave flow flowing through the flow path A2 of the pipe A.
Thus, in the first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, the flow rate of wet steam flowing through the flow path A2 of the pipe A can be measured.

FIG. 8 is a flow chart for explaining the processing executed in the first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment.
In the example shown in FIG. 8, in step S20, for example, the heater control unit 15 determines whether or not it is necessary to switch the heater 14 from the OFF state to the ON state. If it is not necessary to switch the heater 14 from the off state to the on state, the process proceeds to step S21A. On the other hand, if it is necessary to switch the heater 14 from the OFF state to the ON state, the process proceeds to step S21B.
As described above, in the first example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, when the temperature detected by the temperature sensor 17A and the temperature detected by the temperature sensor 17B are equal, for example, heater control The unit 15 determines that the heater 14 needs to be switched from off to on. On the other hand, if the temperature detected by the temperature sensor 17A and the temperature detected by the temperature sensor 17B are different, the heater control unit 15 determines that the heater 14 does not need to be switched from off to on.

In step S21A, the heater control unit 15 keeps the heater 14 off.
Next, in step S22A, during the period in which the heater 14 is maintained in the OFF state, the correlation value calculation unit 13C of the calculation unit 13 determines the waveform of the reception signal output by the reception unit 12B of the second ultrasonic transducer 12 and the , the cross-correlation value with the waveform of the received signal output by the receiving section 11B of the first ultrasonic transducer 11 is calculated.
Next, in step S23A, the propagation time difference calculator 13D of the calculator 13 calculates the propagation time difference based on the position of the correlation peak calculated by the correlation value calculator 13C of the calculator 13 in step S22A.
Next, in step S24A, the flow rate calculation unit 13E of the calculation unit 13 calculates the wet steam flowing through the flow path A2 of the pipe A based on the propagation time difference calculated by the propagation time difference calculation unit 13D of the calculation unit 13 in step S23A. Calculate the flow rate of

In step S21B, the heater control unit 15 switches the heater 14 from off to on.
Next, in step S22B, while the heater 14 is maintained in the ON state, the correlation value calculation unit 13C of the calculation unit 13 calculates the waveform of the reception signal output by the reception unit 12B of the second ultrasonic transducer 12 and the , the cross-correlation value with the waveform of the received signal output by the receiving section 11B of the first ultrasonic transducer 11 is calculated.
Next, in step S23B, the propagation time difference calculator 13D of the calculator 13 calculates the propagation time difference based on the position of the correlation peak calculated by the correlation value calculator 13C of the calculator 13 in step S22B.
Next, in step S24B, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the pipe A obtained by heating by the heater 14 based on the propagation time difference calculated by the propagation time difference calculation unit 13D of the calculation unit 13 in step S23B. The flow rate of dry steam in the flow path A2 is calculated as the flow rate of wet steam flowing in the flow path A2 of the pipe A.
Next, in step S25, the heater control unit 15 switches the heater 14 from ON to OFF.

FIG. 9 is a diagram showing functional blocks of a second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment. FIG. 10 is a diagram showing the configuration of a second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment. Specifically, FIG. 9(A) is a schematic diagram of the main part of the second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment (schematic horizontal sectional view seen from the plus side in the Z-axis direction). , and FIG. 9B is a schematic vertical cross-sectional view of the main part of a second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment as seen from the positive side in the Y-axis direction. (C) is a schematic vertical cross-sectional view of a main portion of a second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, viewed from the minus side in the X-axis direction.
In the examples shown in FIGS. 9 and 10, the clamp-on ultrasonic flowmeter 1 measures the flow rate of wet steam flowing through the flow path A2 of the pipe A. In the example shown in FIGS. The clamp-on type ultrasonic flowmeter 1 includes a first ultrasonic transducer 11, a second ultrasonic transducer 12, a computing section 13, a heater 14, a heater control section 15, a transducer control section 16, and a temperature sensor 17A. and

In the examples shown in FIGS. 9 and 10, the piping A is positioned horizontally (as shown in FIG. left-right direction). The temperature sensor 17A is arranged below the pipe A extending in the horizontal direction (lower portion in FIGS. 7(B) and 7(C)). Specifically, the temperature sensor 17A is arranged below the center axis AX of the pipe A (the lower side in FIGS. 7(B) and 7(C)).

In the example shown in FIGS. 9 and 10, the second ultrasonic transducer 12 is more sensitive to the flow of wet steam flowing in the flow path A2 of the pipe A than the first ultrasonic transducer 11 (FIGS. 10(A) and 10 ( B)) (on the right side in FIGS. 10(A) and 10(B)).
The heater 14 is located upstream of the flow of wet steam flowing through the flow path A2 of the pipe A (Figs. 10A and 10( B) on the left).

In the second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, the heater control section 15 controls the heater 14 based on the temperature detected by the temperature sensor 17A.

If the temperature detected by the temperature sensor 17A is less than the saturated steam equivalent temperature, it can be estimated that wet steam is flowing through the flow path A2 of the pipe A. Further, when the temperature detected by the temperature sensor 17A is equal to or higher than the saturated steam equivalent temperature, it can be estimated that dry steam is flowing through the flow path A2 of the pipe A.
Therefore, in the second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, when the temperature detected by the temperature sensor 17A is less than the saturated steam equivalent temperature, the heater control unit 15 turns on the heater 14 state. As a result, the heater 14 heats the wet steam flowing through the flow path A2 of the pipe A to dry steam. Further, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of dry steam in the flow path A2 of the pipe A obtained by heating by the heater 14 as the flow rate of the wet steam flowing in the flow path A2 of the pipe A. .
Further, when the temperature detected by the temperature sensor 17A is equal to or higher than the saturated steam equivalent temperature, the heater control unit 15 turns off the heater 14 . Further, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the dry steam flowing through the flow path A2 of the pipe A.
Thus, in the second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, the flow rate of wet steam flowing through the flow path A2 of the pipe A can be measured.

FIG. 11 is a flow chart for explaining the processing executed in the second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment.
In the example shown in FIG. 11, in step S30, for example, the heater control unit 15 determines whether or not it is necessary to switch the heater 14 from the OFF state to the ON state. If it is not necessary to switch the heater 14 from the off state to the on state, the process proceeds to step S31A. On the other hand, if it is necessary to switch the heater 14 from the OFF state to the ON state, the process proceeds to step S31B.
As described above, in the second example of the clamp-on type ultrasonic flowmeter 1 of the second embodiment, when the temperature detected by the temperature sensor 17A is less than the saturated steam equivalent temperature, for example, the heater control unit 15 It is determined that it is necessary to switch the heater 14 from the OFF state to the ON state. On the other hand, when the temperature detected by the temperature sensor 17A is equal to or higher than the saturated steam equivalent temperature, the heater control unit 15 determines that it is not necessary to switch the heater 14 from the OFF state to the ON state.

In step S31A, the heater controller 15 keeps the heater 14 off.
Next, in step S32A, during the period in which the heater 14 is maintained in the OFF state, the correlation value calculation unit 13C of the calculation unit 13 calculates the waveform of the reception signal output by the reception unit 12B of the second ultrasonic transducer 12 and the , the cross-correlation value with the waveform of the received signal output by the receiving section 11B of the first ultrasonic transducer 11 is calculated.
Next, in step S33A, the propagation time difference calculator 13D of the calculator 13 calculates the propagation time difference based on the position of the correlation peak calculated by the correlation value calculator 13C of the calculator 13 in step S32A.
Next, in step S34A, the flow rate calculation unit 13E of the calculation unit 13 calculates the dry steam flowing through the flow path A2 of the pipe A based on the propagation time difference calculated by the propagation time difference calculation unit 13D of the calculation unit 13 in step S33A. Calculate the flow rate of

In step S31B, the heater control unit 15 switches the heater 14 from off to on.
Next, in step S32B, while the heater 14 is maintained in the ON state, the correlation value calculator 13C of the calculator 13 calculates the waveform of the received signal output by the receiver 12B of the second ultrasonic transducer 12 and , the cross-correlation value with the waveform of the received signal output by the receiving section 11B of the first ultrasonic transducer 11 is calculated.
Next, in step S33B, the propagation time difference calculator 13D of the calculator 13 calculates the propagation time difference based on the position of the correlation peak calculated by the correlation value calculator 13C of the calculator 13 in step S32B.
Next, in step S34B, the flow rate calculation unit 13E of the calculation unit 13 calculates the flow rate of the pipe A obtained by heating by the heater 14 based on the propagation time difference calculated by the propagation time difference calculation unit 13D of the calculation unit 13 in step S33B. The flow rate of dry steam in the flow path A2 is calculated as the flow rate of wet steam flowing in the flow path A2 of the pipe A.
Next, in step S35, the heater control unit 15 switches the heater 14 from ON to OFF.

<Application example>
By plotting the flow rate of wet steam calculated by the flow rate calculation unit 13E of the calculation unit 13 of the clamp-on type ultrasonic flowmeter 1 of the first or second embodiment on a known flow pattern diagram, the flow rate of the pipe A The wetness of the steam flowing through the flow path A2 can be grasped.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and examples, and can be changed as appropriate without departing from the scope of the present invention. can be added. You may combine the structure as described in each embodiment and each example which were mentioned above.

DESCRIPTION OF SYMBOLS 1... Clamp-on type ultrasonic flowmeter, 11... 1st ultrasonic transducer, 11A... Transmission part, 11B... Reception part, 12... 2nd ultrasonic transducer, 12A... Transmission part, 12B... Reception part, 13... Operation part , 13A first received signal acquisition unit 13B second received signal acquisition unit 13C correlation value calculation unit 13D propagation time difference calculation unit 13E flow rate calculation unit 14 heater 15 heater control unit 16 ... Transducer control unit 17A, 17B ... Temperature sensor A ... Piping A1 ... Wall part A2 ... Flow path AX ... Central axis

Claims (13)

A clamp-on ultrasonic flowmeter for measuring the flow rate of wet steam flowing in a pipe flow path,
a first ultrasonic transducer having a first transmitter and a first receiver for transmitting a first ultrasonic wave;
a second ultrasonic transducer having a second transmitting section and a second receiving section for transmitting a second ultrasonic wave and arranged downstream of the first ultrasonic transducer in the flow of the wet steam;
A first reception signal output by the second receiving unit that has received the first ultrasonic wave that has passed through the flow channel, and the first receiving unit that has received the second ultrasonic wave that has passed through the flow channel The flow rate of the wet steam is calculated by calculating the propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the second received signal output by a calculation unit that
a heater disposed on the upstream side of the flow of the wet steam relative to the first ultrasonic transducer and the second ultrasonic transducer and heating the wet steam flowing in the flow path to dry steam ;
A heater control unit that controls the heater,
The computing section computes a cross-correlation between the waveform of the first received signal output by the second receiving section and the waveform of the second received signal output by the first receiving section. calculating the propagation time difference based on the position of the correlation peak;
The heater control unit
when the value of the correlation peak obtained by the computing unit is equal to or less than a first threshold, turning the heater from an off state to an on state;
maintaining the heater in an off state when the value of the correlation peak obtained by the computing unit is greater than the first threshold;
Clamp-on type ultrasonic flowmeter. A clamp-on ultrasonic flowmeter for measuring the flow rate of wet steam flowing in a pipe flow path,
a first ultrasonic transducer having a first transmitter and a first receiver for transmitting a first ultrasonic wave;
a second ultrasonic transducer having a second transmitting section and a second receiving section for transmitting a second ultrasonic wave and arranged downstream of the first ultrasonic transducer in the flow of the wet steam;
A first reception signal output by the second receiving unit that has received the first ultrasonic wave that has passed through the flow channel, and the first receiving unit that has received the second ultrasonic wave that has passed through the flow channel The flow rate of the wet steam is calculated by calculating the propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the second received signal output by a calculation unit that
a heater disposed on the upstream side of the flow of the wet steam relative to the first ultrasonic transducer and the second ultrasonic transducer and heating the wet steam flowing in the flow path to dry steam ;
A heater control unit that controls the heater,
The heater control unit
when at least one of the signal/noise ratio of the first received signal output by the second receiving unit and the signal/noise ratio of the second received signal output by the first receiving unit is equal to or less than a second threshold; , turning the heater from off to on;
When the signal/noise ratio of the first received signal output by the second receiving unit and the signal/noise ratio of the second received signal output by the first receiving unit are greater than the second threshold, keep the heater off,
Clamp-on type ultrasonic flowmeter. A clamp-on ultrasonic flowmeter for measuring the flow rate of wet steam flowing in a pipe flow path,
a first ultrasonic transducer having a first transmitter and a first receiver for transmitting a first ultrasonic wave;
a second ultrasonic transducer having a second transmitting section and a second receiving section for transmitting a second ultrasonic wave and arranged downstream of the first ultrasonic transducer in the flow of the wet steam;
A first reception signal output by the second receiving unit that has received the first ultrasonic wave that has passed through the flow channel, and the first receiving unit that has received the second ultrasonic wave that has passed through the flow channel The flow rate of the wet steam is calculated by calculating the propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the second received signal output by a calculation unit that
a heater disposed on the upstream side of the flow of the wet steam relative to the first ultrasonic transducer and the second ultrasonic transducer and heating the wet steam flowing in the flow path to dry steam ;
A heater control unit that controls the heater,
The heater control unit
The first ultrasonic wave as an airborne wave transmitted from the first transmitter and transmitted through the flow path, and the pipe propagated wave transmitted from the first transmitter and propagated through the wall of the pipe. If the first received signal, which is the received signal of the first ultrasonic wave, cannot be identified from the signal containing noise output by the second receiving unit that has received the output by the first receiving unit that has received the second ultrasonic wave as an airborne wave that has passed through the flow path, and the in-tube wave that has been transmitted from the second transmitting unit and has passed through the wall when the second received signal, which is the received signal of the second ultrasonic wave, cannot be identified from the signal containing noise, turning the heater from the OFF state to the ON state;
The first ultrasonic wave as an airborne wave transmitted from the first transmission unit and transmitted through the flow path, and an in-pipe wave transmitted from the first transmission unit and propagated through the wall of the pipe When the first received signal, which is the received signal of the first ultrasonic wave, can be identified from the signal containing noise output by the second receiving unit that has received the Output by the first receiving unit that receives the second ultrasonic wave as an airborne wave that has passed through the flow path and the in-pipe wave that has been transmitted from the second transmitting unit and has passed through the wall maintaining the heater in an off state when the second received signal, which is the received signal of the second ultrasonic wave, can be identified from the signal containing noise received;
Clamp-on type ultrasonic flowmeter. A clamp-on ultrasonic flowmeter for measuring the flow rate of wet steam flowing in a pipe flow path,
a first ultrasonic transducer having a first transmitter and a first receiver for transmitting a first ultrasonic wave;
a second ultrasonic transducer having a second transmitting section and a second receiving section for transmitting a second ultrasonic wave and arranged downstream of the first ultrasonic transducer in the flow of the wet steam;
A first reception signal output by the second receiving unit that has received the first ultrasonic wave that has passed through the flow channel, and the first receiving unit that has received the second ultrasonic wave that has passed through the flow channel The flow rate of the wet steam is calculated by calculating the propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the second received signal output by a calculation unit that
a heater disposed on the upstream side of the flow of the wet steam relative to the first ultrasonic transducer and the second ultrasonic transducer and heating the wet steam flowing in the flow path to dry steam ;
a heater control unit that controls the heater ;
further comprising at least a first temperature sensor and a second temperature sensor;
The pipe extends horizontally at a position where the first ultrasonic transducer and the second ultrasonic transducer are arranged,
The first temperature sensor and the second temperature sensor are arranged at different positions in the vertical direction of the pipe extending in the horizontal direction,
The heater control unit
turning on the heater when the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are equal;
turning off the heater when the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are different;
Clamp-on type ultrasonic flowmeter. After the calculation unit calculates the flow rate of the dry steam corresponding to the flow rate of the wet steam during the period in which the heater is maintained in the ON state,
the heater control unit switches the heater from an on state to an off state;
The clamp-on type ultrasonic flowmeter according to any one of claims 1 to 4. The heater control unit
switching the heater from the ON state to the OFF state when a preset time has elapsed after switching the heater from the OFF state to the ON state;
The clamp-on type ultrasonic flowmeter according to any one of claims 1 to 4. further comprising at least a first temperature sensor and a second temperature sensor;
The pipe extends horizontally at a position where the first ultrasonic transducer and the second ultrasonic transducer are arranged,
The first temperature sensor and the second temperature sensor are arranged at different positions in the vertical direction of the pipe extending in the horizontal direction,
The heater control unit
turning on the heater when the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are equal;
turning off the heater when the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are different;
The clamp-on type ultrasonic flowmeter according to any one of claims 1 to 3 . further comprising a temperature sensor,
The pipe extends horizontally at a position where the first ultrasonic transducer and the second ultrasonic transducer are arranged,
The temperature sensor is arranged below the pipe extending in the horizontal direction,
turning on the heater when the temperature detected by the temperature sensor is less than the saturated steam equivalent temperature;
turning off the heater when the temperature detected by the temperature sensor is equal to or higher than the saturated steam equivalent temperature;
The clamp-on type ultrasonic flowmeter according to any one of claims 1 to 4 . The pipe extends horizontally at a position where the first ultrasonic transducer, the second ultrasonic transducer and the heater are arranged,
The heater is arranged below the central axis of the pipe,
The clamp-on type ultrasonic flowmeter according to any one of claims 1 to 8. a first ultrasonic transducer having a first transmitter and a first receiver for transmitting a first ultrasonic wave;
A second transmitter having a second transmitter and a second receiver for transmitting a second ultrasonic wave, and arranged downstream of the flow of the wet steam flowing in the flow path of the pipe from the first ultrasonic transducer. an ultrasonic transducer;
Clamp-on ultrasonic flow measurement for measuring the flow rate of the wet steam by using the first ultrasonic transducer and a heater arranged upstream of the flow of the wet steam relative to the second ultrasonic transducer. a method,
Waveform of a first reception signal output by the second receiving unit that has received the first ultrasonic wave that has passed through the flow channel and the first reception that has received the second ultrasonic wave that has passed through the flow channel a first step of calculating a correlation peak obtained by calculating cross-correlation with respect to the waveform of the second received signal output by the unit;
When the value of the correlation peak obtained in the first step is equal to or less than the first threshold, the heater is turned on from the OFF state, and the value of the correlation peak obtained in the first step is greater than the first threshold. a second step of keeping the heater off when the
a third step, when it is determined in the second step that the heater is to be switched from the OFF state to the ON state, the wet steam flowing through the flow path is heated by the heater to be dry steam;
A fourth step of calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the correlation peak between the first received signal and the second received signal. and,
a fifth step of calculating the flow rate of the wet steam based on the propagation time difference calculated in the fourth step;
Clamp-on type ultrasonic flow measurement method. a first ultrasonic transducer having a first transmitter and a first receiver for transmitting a first ultrasonic wave;
A second transmitter having a second transmitter and a second receiver for transmitting a second ultrasonic wave, and arranged downstream of the flow of the wet steam flowing in the flow path of the pipe from the first ultrasonic transducer. an ultrasonic transducer;
Clamp-on ultrasonic flow measurement for measuring the flow rate of the wet steam by using the first ultrasonic transducer and a heater arranged upstream of the flow of the wet steam relative to the second ultrasonic transducer. a method,
The signal/noise ratio of the first reception signal output by the second receiving unit that received the first ultrasonic wave transmitted through the flow channel and the second ultrasonic wave transmitted through the flow channel When at least one of the signal/noise ratio of the second reception signal output by the first reception unit is equal to or less than the second threshold, the heater is turned on from the off state, and the a first step of keeping the heater off if the signal/noise ratio of the first received signal and the signal/noise ratio of the second received signal output by the first receiver are greater than the second threshold; and,
a second step, when it is determined in the first step that the heater is to be switched from the OFF state to the ON state, the wet steam flowing through the flow path is heated by the heater to become dry steam;
a third step of calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the first received signal and the second received signal;
a fourth step of calculating the flow rate of the wet steam based on the propagation time difference calculated in the third step;
Clamp-on type ultrasonic flow measurement method. a first ultrasonic transducer having a first transmitter and a first receiver for transmitting a first ultrasonic wave;
A second transmitter having a second transmitter and a second receiver for transmitting a second ultrasonic wave, and arranged downstream of the flow of the wet steam flowing in the flow path of the pipe from the first ultrasonic transducer. an ultrasonic transducer;
Clamp-on ultrasonic flow measurement for measuring the flow rate of the wet steam by using the first ultrasonic transducer and a heater arranged upstream of the flow of the wet steam relative to the second ultrasonic transducer. a method,
The first ultrasonic wave as an airborne wave transmitted from the first transmitter and transmitted through the flow path, and the pipe propagated wave transmitted from the first transmitter and propagated through the wall of the pipe. If the first received signal, which is the received signal of the first ultrasonic wave, cannot be identified from the signal containing noise output by the second receiving unit that received the above, or the flow transmitted from the second transmitting unit Noise output by the first receiving unit that has received the second ultrasonic wave as an airborne wave that has passed through the passage and the pipe-propagating wave that has been transmitted from the second transmitting unit and has passed through the wall. When the second received signal, which is the received signal of the second ultrasonic wave, cannot be identified from the signal containing noise output by the second receiving unit that has received the first ultrasonic wave as an airborne wave and an in-pipe propagating wave transmitted from the first transmitting unit and propagated in the wall of the pipe When the first received signal, which is the received signal of the first ultrasonic wave, can be identified from the signal including the Reception of the second ultrasonic wave from a signal containing noise output by the first receiving unit that has received the second ultrasonic wave and the in-pipe propagation wave transmitted from the second transmitting unit and transmitted through the wall. a first step of keeping the heater off if the second received signal can be identified as a signal;
a second step, when it is determined in the first step that the heater is to be switched from the OFF state to the ON state, the wet steam flowing through the flow path is heated by the heater to become dry steam;
a third step of calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the first received signal and the second received signal;
a fourth step of calculating the flow rate of the wet steam based on the propagation time difference calculated in the third step;
Clamp-on type ultrasonic flow measurement method. a first ultrasonic transducer having a first transmitter and a first receiver for transmitting a first ultrasonic wave arranged in a pipe extending in a horizontal direction ;
It has a second transmitter and a second receiver that transmit a second ultrasonic wave, and is arranged in the pipe on the downstream side of the flow of wet steam flowing in the flow path of the pipe from the first ultrasonic transducer. a second ultrasonic transducer,
By using a heater positioned upstream of the wet steam flow relative to the first and second ultrasonic transducers, and at least a first temperature sensor and a second temperature sensor , the wetness A clamp-on type ultrasonic flow measurement method for measuring the flow rate of steam,
When the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are equal, the heater is turned on, and the temperature detected by the first temperature sensor and the temperature detected by the second temperature sensor are turned on. a first step of turning off the heater if the temperature detected by
a second step, when it is determined in the first step that the heater is to be switched from the OFF state to the ON state, the wet steam flowing through the flow path is heated by the heater to become dry steam;
A first reception signal output by the second receiving unit that has received the first ultrasonic wave that has passed through the flow channel, and the first receiving unit that has received the second ultrasonic wave that has passed through the flow channel a third step of calculating a propagation time difference, which is the difference between the propagation time of the first ultrasonic wave and the propagation time of the second ultrasonic wave, based on the second received signal output by ;
a fourth step of calculating the flow rate of the wet steam based on the propagation time difference calculated in the third step;
Clamp-on type ultrasonic flow measurement method.

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