JP2008122102A - Ultrasonic type meter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of simplification and cost reduction, and quick and accurate derivation of a flow velocity value, in an ultrasonic type meter device for measuring a propagation time of an ultrasonic wave in a fluid such as a gas flowing along a measuring channel, and deriving the flow velocity value relative to the flow velocity such as the flow velocity or the flow rate of the fluid from the propagation time. <P>SOLUTION: The ultrasonic type meter device 1 includes a temperature deriving means 27 for deriving the temperature of a transmitter/receiver 6, a heater 33 as a temperature adjusting means for adjusting the temperature of the transmitter/receiver 6, and a temperature setting means 32 for setting the temperature of the transmitter/receiver 6 within a setting temperature range by controlling the heater 33 based on a derivation result by the temperature deriving means 27. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic meter device that measures the propagation time of an ultrasonic wave in a fluid such as a gas flowing in a measurement flow path and derives a flow velocity value related to the flow velocity such as a flow velocity and a flow rate of the fluid from the propagation time.

  Conventionally, this type of ultrasonic meter device has been installed with a pair of ultrasonic transmitters / receivers capable of transmitting and receiving ultrasonic waves to and from the upstream and downstream sides of a measurement channel through which a fluid flows. Based on the measurement result of the propagation time measuring means for receiving the ultrasonic wave transmitted from one side of the transmitter on the other side and measuring the propagation time of the ultrasonic wave between the pair of ultrasonic transceivers And a flow velocity value calculating means for deriving the flow velocity value (see, for example, Patent Document 1).

Specifically, the propagation time measuring means includes a forward propagation time t1 in which the ultrasonic wave propagates between the pair of ultrasonic transceivers in the forward direction along the fluid flow direction, and a reverse direction opposite to the forward direction. A backward propagation time t2 in which the ultrasonic wave propagates between the pair of ultrasonic transceivers is measured. The forward propagation time t1 and the backward propagation time t2 measured in this way are the instantaneous flow velocity of the fluid along the opposing direction between the ultrasonic transmitters and receivers in the measurement channel, and v ′, When the speed of sound is C and the distance between the ultrasonic transceivers is L, the following equation is obtained.
t1 = L / (C + v ′)
t2 = L / (Cv ′)

The flow velocity v ′ can be obtained by the following equation regardless of the sound velocity C.
v ′ = L · (1 / t1-1 / t2) / 2

  Therefore, the flow velocity value calculation means uses the flow velocity v ′ obtained by the above equation to calculate the flow velocity of the fluid in the measurement channel, or the flow rate obtained by multiplying the flow velocity by the channel cross-sectional area of the measurement channel. It can be derived as a value.

Further, in the conventional ultrasonic meter device, the received signal of the ultrasonic transmitter / receiver that has received the ultrasonic wave has a waveform that attenuates after the amplitude gradually increases, even if it is amplified to the maximum set voltage. Therefore, the time immediately after the reception signal is received has a very small amplitude, and it is difficult to accurately recognize the reception time. In the present application, the waveform of the received signal indicates the ratio of the maximum voltage of each wave to the maximum voltage of the entire received signal.
Therefore, the propagation time measuring means determines the ultrasonic wave reception time of the ultrasonic wave transmitter / receiver with reference to the time point when the amplitude of the received signal becomes large enough to be accurately recognized. The received signal and the reference voltage are compared for determination.
For example, the propagation time measuring means obtains a time point (hereinafter referred to as “zero cross point”) when the received signal becomes zero level immediately after the received signal reaches the reference voltage. Assuming that the waveform of the received signal is constant, the zero cross point obtained in this way coincides with the zero cross point of the specific wave from the reception time point (hereinafter referred to as “target wave”). The delay time from to the zero cross point can be recognized in advance as a value that is a fixed multiple of the period of the received signal.
Therefore, the propagation time measuring means can accurately determine the time point before the delay time from the zero cross point obtained as described above as the reception time point.

However, when the waveform of the received signal changes, for example, the wave of the received signal exceeding the reference voltage is not the target wave but the waves before and after the target wave, and the reception time may not be accurately determined.
Therefore, in the conventional ultrasonic meter device, while changing the reference voltage, the propagation time of the ultrasonic wave between the pair of ultrasonic transmitters / receivers and the time difference from the time when the received signal reaches the reference voltage to the zero cross point are sequentially changed. Thus, the optimum reference voltage detection process for detecting the optimum reference voltage for detecting the zero-cross point of the target wave is executed from the propagation time and the change state of the time difference.
The flow velocity value is derived from the propagation time of the ultrasonic wave measured by setting the reference voltage to the optimum one detected by the optimum reference voltage detection process.
In this type of ultrasonic meter device, even when the received signal changes, the optimum reference voltage for detecting the zero-cross point of the target wave is detected by executing the optimum reference voltage detection process. Thus, an accurate flow velocity value can be derived.

JP 2003-106882 A

However, in the ultrasonic meter device described in Patent Document 1, since it is necessary to execute the optimum reference voltage detection process as described above, the device configuration becomes complicated and the cost is increased. There was a problem that it took a long time to derive.
As described above, if the time until the flow velocity value is derived becomes long, the flow velocity of the fluid may change significantly while the time elapses, and the reference voltage detected in the optimum reference voltage detection process is However, it is not optimal for deriving the flow velocity value, and there is a problem that an accurate flow velocity value cannot be derived.

  The present invention has been made in view of the above problems, and its purpose is to measure the propagation time of an ultrasonic wave in a fluid such as a gas flowing through a measurement flow path, and to determine the flow velocity and flow rate of the fluid from the propagation time. In the ultrasonic meter device for deriving a flow velocity value related to the flow velocity, it is possible to simplify and reduce the cost, and to provide a technique capable of deriving the flow velocity value quickly and accurately.

  In order to achieve the above object, an ultrasonic meter device according to the present invention is provided with a pair of ultrasonic transmitters / receivers capable of transmitting / receiving ultrasonic waves to / from an upstream side and a downstream side of a measurement channel through which a fluid flows, Propagation time measuring means for receiving ultrasonic waves transmitted from one side of the pair of ultrasonic transceivers on the other side and measuring ultrasonic propagation time between the pair of ultrasonic transceivers, and the propagation time A flow velocity value calculating means for deriving a flow velocity value related to the flow velocity of the fluid flowing through the measurement flow path based on the measurement result of the measurement means, and the propagation time measuring means determines the reception time of the ultrasonic waves of the ultrasonic transceiver. An ultrasonic meter device configured to make a determination by comparing a received signal of the ultrasonic transceiver and a reference voltage, the first characteristic configuration is a temperature for deriving the temperature of the ultrasonic transceiver Deriving means and the supersonic sound Temperature adjusting means for adjusting the temperature of the transceiver, and temperature setting means for controlling the temperature adjusting means based on a result derived by the temperature deriving means to set the temperature of the ultrasonic transceiver within a set temperature range. It is in the point prepared.

According to the first characteristic configuration, when a predetermined reference voltage is determined in advance by a relatively simple configuration including the temperature deriving unit, the temperature adjusting unit, and the temperature setting unit, the reference is sequentially performed. Accurate flow velocity value can be obtained by accurately identifying the reception time of the received signal and obtaining the correct propagation time without the need to detect the voltage by the optimum reference voltage detection processing as described in the background art section. it can.
That is, by setting the temperature of the ultrasonic transceiver within the set temperature range, it is possible to prevent a change in the waveform of the received signal of the ultrasonic transceiver due to a change in the temperature of the ultrasonic transceiver. By adopting such a relatively simple configuration, the reason why an accurate flow velocity value can be derived by setting the reference voltage to a predetermined value is that the change factor of the waveform of the received signal is mainly governed by temperature. The inventors found out that the temperature of the ultrasonic transmitter / receiver was set within a predetermined set temperature range. Therefore, even when the reference voltage is set to a predetermined value, the reception time point can be accurately specified, and an accurate flow velocity value can be derived by obtaining an accurate propagation time.

  A second characteristic configuration of the ultrasonic meter device according to the present invention includes, in addition to the first characteristic configuration, a heater capable of heating the ultrasonic transceiver as the temperature adjusting unit, and the temperature setting unit includes: The heater is operated when the temperature of the ultrasonic transmitter / receiver derived by the temperature deriving means falls below a set temperature range.

  When the temperature of the ultrasonic transmitter / receiver is lower than the set temperature range, the waveform of the received signal of the ultrasonic transmitter / receiver in the low temperature state changes compared to the waveform of the received signal of the ultrasonic transmitter / receiver in the set temperature range. . Therefore, according to the second feature configuration, since the temperature of the ultrasonic transmitter / receiver is maintained within the set temperature range by the heating of the heater, the change of the waveform of the received signal is prevented, and a predetermined target wave is used. A zero-cross point can be derived and an accurate flow velocity value can be derived.

  A third characteristic configuration of the ultrasonic meter device according to the present invention is that, in addition to the second characteristic configuration, the temperature setting means sets the temperature of the ultrasonic transceiver to a lower limit value of a set temperature range. is there.

  According to the third characteristic configuration, the temperature setting means sets the temperature of the ultrasonic transmitter / receiver to the lower limit value of the set temperature range in a low temperature state where the temperature of the ultrasonic transmitter / receiver falls below the set temperature range. By reducing the temperature adjustment range and heating time by the heater from the state to the set temperature range, the energy required for heating can be reduced.

  A fourth characteristic configuration of the ultrasonic meter device according to the present invention includes, in addition to any one of the first to third characteristic configurations, a peak voltage measuring unit that measures a peak voltage of a reception signal of the ultrasonic transceiver. And the temperature deriving means derives the temperature of the ultrasonic transceiver based on the peak voltage measured by the peak voltage measuring means.

  According to the fourth characteristic configuration, the lower the temperature of the ultrasonic transceiver, the smaller the peak voltage of the received signal (the maximum voltage of the entire received signal before amplification) becomes smaller. The temperature of the ultrasonic transmitter / receiver is easily determined based on the peak voltage in such a form that the temperature of the ultrasonic transmitter / receiver is lower as the peak voltage of the received signal of the ultrasonic transmitter / receiver measured by the peak voltage measuring means is smaller. Can be derived.

  The fifth characteristic configuration of the ultrasonic meter device according to the present invention is the sound characteristic in the measurement flow path based on the measurement result of the propagation time measuring means in addition to any one of the first to third characteristic configurations. There is a sonic speed calculating means for deriving, and the temperature deriving means derives the temperature of the ultrasonic transceiver based on the sound speed derived by the sonic speed calculating means.

By the propagation time measuring means, a forward propagation time in which the ultrasonic wave propagates between the pair of ultrasonic transmitters / receivers in the forward direction along the fluid flow direction, and a pair of ultrasonic waves in a direction opposite to the forward direction. The velocity of sound can be obtained from the propagation time by measuring the backward propagation time propagating between the ultrasonic transceivers.
Furthermore, since the speed of sound in the measurement channel is expressed as a function of the temperature in the measurement channel, the temperature in the measurement channel can be obtained by obtaining the speed of sound, and that temperature is the temperature of the ultrasonic transceiver. Can do. Since the ultrasonic transmitter / receiver is installed in the measurement channel, the temperature of the ultrasonic transmitter / receiver becomes the temperature in the measurement channel or a temperature close thereto.
That is, according to the fifth characteristic configuration, the sound speed calculation means derives the sound speed in the measurement channel based on the measurement result of the propagation time measurement means, and the temperature deriving means uses the ultrasonic wave transceiver based on the sound speed. The temperature can be easily derived.

  The sixth characteristic configuration of the ultrasonic meter device according to the present invention is such that, in addition to any one of the first to fifth characteristic configurations, the received signal of the ultrasonic transmitter / receiver maximizes a set voltage. It is in the point provided with the amplification means to amplify.

  According to the sixth characteristic configuration, when the reception signal of the ultrasonic transceiver is weak overall, in other words, even when the voltage of the reception signal of the ultrasonic transceiver is small overall, the reception signal is By amplifying, the overall strength of the received signal after amplification can be stabilized to some extent. Therefore, it is possible to more accurately determine the reception time of the ultrasonic wave in the ultrasonic transceiver by comparing the amplified reception signal with the reference voltage.

  The seventh characteristic configuration of the ultrasonic meter device according to the present invention includes, in addition to any one of the first to fifth characteristic configurations, a voltage having a predetermined ratio with respect to a peak voltage of a reception signal of the ultrasonic transceiver. A reference voltage setting means for setting the reference voltage is provided.

  That is, according to the seventh characteristic configuration, even when the intensity of the reception signal of the ultrasonic transceiver fluctuates as a whole, the reference voltage is set to a voltage having a predetermined ratio with respect to the peak voltage of the reception signal. The relative height of the reference voltage with respect to the overall strength of the signal can be stabilized to some extent. Therefore, it is possible to more accurately determine the reception time point of the ultrasonic wave in the ultrasonic transceiver by comparing the received signal with the reference voltage.

An embodiment of an ultrasonic meter device according to the present invention will be described with reference to the drawings.
FIG. 1 shows a flow velocity relating to a flow rate such as a flow rate or a flow rate of a gas g (an example of a fluid) flowing through a measurement channel 2 by an ultrasonic meter device (hereinafter referred to as “this device”) 1 according to the present embodiment. It is side sectional drawing of this apparatus in the state which has implemented derivation | leading-out of the value.
In FIG. 1, the flow direction of the gas g in the measurement channel 2 is a direction from left to right.

First, the basic configuration of this apparatus will be described.
As shown in FIG. 1 and FIG. 2, this apparatus is disposed at both ends of the measurement flow channel 2 in a direction that obliquely crosses between the upstream side and the downstream side, and is superordinate to each other along the transverse direction. The measurement channel 2 is determined by a pair of ultrasonic transmitters / receivers (hereinafter abbreviated as “transmitter / receiver”) 6 capable of transmitting and receiving sound waves and the propagation state of ultrasonic waves in the measurement channel 2 measured by the pair of transmitters / receivers 6. The control apparatus 50 comprised so that the flow velocity value of the gas g which distribute | circulates was derived | led-out was provided. Further, the present apparatus includes a relatively large upstream space 3 on the upstream side of the measurement flow path 2, and the gas g flows into the measurement flow path 2 through the upstream space 3.

  The transmitter / receiver 6a installed on the upstream side of the measurement channel 2 and the transmitter / receiver 6b installed on the downstream side of the measurement channel 2 are installed facing each other at a position separated by a distance L. The facing direction of the transmitter / receiver 6 and the flow direction of the gas g flowing through the measurement flow path 2 (the direction along the central axis of the measurement flow path 2) form an angle θ.

  In addition, when a drive pulse that is an electrical signal is input from the control device 50 side, the transmitter / receiver 6 transmits an ultrasonic wave toward the other transmitter / receiver 6 side, while transmitting from the other transmitter / receiver 6 side. When the received ultrasonic wave is received, a reception signal which is an electric signal is output to the control device 50 side.

  The control device 50 is configured by a microcomputer including a storage medium including a memory, a CPU, an input / output unit, and the like, and the computer executes a predetermined program, thereby causing a propagation time measuring unit 10 and a flow velocity value calculation to be described later. It functions as various means such as means 20, reference voltage setting means 25, temperature deriving means 27, temperature setting means 32, and the like. Hereinafter, a detailed configuration of each unit will be described.

  The propagation time measuring means 10 in which the control device 50 functions includes a switching unit 11 that switches between a transmission state of a driving pulse and a reception state of a reception signal for each of the pair of transceivers 6, and ultrasonic waves to the transceiver 6 through the switching unit 11. A driving unit 12 for outputting a driving pulse for generating a signal, an amplifying unit 13 for amplifying a received signal of the transceiver 6 inputted through the switching unit 11, and a reference voltage to be described later for the received signal amplified by the amplifying unit 13. The reception time determination unit 14 that determines the reception time of the ultrasonic waves of the transmitter / receiver 6 as compared with the time measurement that is measured as the propagation time of the ultrasonic waves between the pair of transmitters / receivers 6 based on the determination result of the reception time determination unit 14 Part 15.

  The switching unit 11 transmits the drive pulse input from the drive unit 12 to the upstream side transmitter / receiver 6 a of the pair of transmitters / receivers 6, and receives the reception signal received from the downstream side transmitter / receiver 6 b to the amplification unit 13. In contrast to the forward propagation state to be output, conversely, the drive pulse input from the drive unit 12 is transmitted to the downstream transmitter / receiver 6b of the pair of transmitters / receivers 6, and the received signal received from the upstream transmitter / receiver 6a is transmitted. It is configured to switch the reverse propagation state output to the amplifying unit 13.

  As shown in FIG. 2, the reception time point determination unit 14 has a zero level immediately after the reception signal amplified by the amplification unit 13 reaches a predetermined reference voltage set by a reference voltage setting unit 25 described later. The zero cross point is determined, and a time point a predetermined delay time before the zero cross point is determined as the reception time point.

  Then, the time measuring unit 15 refers to the time from the transmission time when the driving pulse is output by the driving unit 12 to the reception time determined by the reception time determining unit 14 while referring to the time measured by the timer 28. It is configured to measure the propagation time of ultrasonic waves between the six.

  Then, the control device 50 switches the switching unit 11 between the forward propagation state and the backward propagation state, so that the timer unit 15 in the forward direction along the flow direction of the gas g flowing through the measurement flow channel 2. The ultrasonic wave is transmitted in a direction opposite to the forward direction along the flow direction of the gas g flowing through the measurement flow path 2 and the forward propagation time t1 in which the ultrasonic wave propagates between the pair of transceivers 6 in the direction. It is configured to measure the backward propagation time t2 that propagates between the transceivers 6.

  The flow velocity value calculation means 20 in which the control device 50 functions is configured to derive a flow velocity value related to the flow velocity of the gas g flowing through the measurement flow path 2 based on the measurement result of the propagation time measurement means 10. The method for deriving the flow velocity value will be described below.

The instantaneous flow velocity of the gas g along the facing direction between the pair of transceivers 6 is denoted by v ′, the instantaneous flow velocity along the flow direction of the measurement flow path 2 is denoted by v, and the angle between the facing direction and the flow direction is θ. Assuming that the distance between the pair of transceivers 6 is L and the sound velocity in the gas g is C, the forward propagation time t1 and the backward propagation time t2 measured by the propagation time measuring means 10 are as follows: As shown in FIG.
t1 = L / (C + v ′) = L / (C + v · cos θ)
t2 = L / (Cv ′) = L / (Cv · cos θ)

From these equations, the instantaneous flow velocity v is a function obtained only from the forward propagation time t1, the backward propagation time t2, and the distance L as shown in the following equation.
v = L · (1 / t1-1 / t2) / (2 · cos θ)

Therefore, the flow velocity value calculating means 20 uses the above function to calculate the instantaneous flow velocity of the gas g flowing through the measurement flow path 2 from the forward propagation time t1 and the backward propagation time t2 measured by the propagation time measuring means 10. per unit time obtained by deriving v and calculating the instantaneous flow rate v itself, or the instantaneous flow rate v obtained by multiplying the instantaneous flow rate v by the cross-sectional area of the measurement flow path 2 or the instantaneous flow rate per unit time. Is derived as the flow velocity value.
Further, the control device 50 can display or store the flow velocity value derived in this way or output it to the outside.

Next, the characteristic configuration of this apparatus will be described.
The amplifying unit 13 maximizes the preset set voltage for the received signal of the transmitter / receiver 6 input through the switching unit 11 in order to stabilize the strength of the received signal after the amplifier 6 amplifies. It is comprised as an amplification means to amplify.
The received signal of the transmitter / receiver 6 that has received the ultrasonic wave (the output of the amplifying unit 13) has a waveform that attenuates after the amplitude gradually increases, as shown in FIG. Since the waveform of the received signal changes due to the temperature change of the transmitter / receiver 6, the reception time determination unit 14 determines the reception time of the ultrasonic wave of the transmitter / receiver 6 between the received signal of the transmitter / receiver 6 and the reference voltage. In determining by comparison, if the reference voltage is set to a predetermined value, the wave of the received signal exceeding the reference voltage is not the predetermined target wave, and as a result, the reception time point may not be determined accurately.

  In view of this, the present apparatus can be simplified and reduced in cost, and in order to quickly and accurately derive the flow velocity value, as shown in FIG. 1, the temperature deriving means 27 for deriving the temperature of the transceiver 6 and the transceiver A heater 33 as temperature adjusting means for adjusting the temperature of 6, and a temperature setting means 32 for setting the temperature of the transceiver 6 within a set temperature range by controlling the heater 33 based on the result derived by the temperature deriving means 27. These detailed configurations will be described below.

  The peak voltage measuring means 26 for measuring the peak voltage of the received signal before amplification in the transceiver 6 input to the amplifying unit 13 as the amplifying means is provided. The temperature deriving means 27 is provided by the peak voltage measuring means 26. Based on the measured peak voltage, the temperature of the transmitter / receiver 6 is derived.

That is, by utilizing the fact that the peak voltage decreases as the temperature of the transmitter / receiver 6 decreases, the correlation between the temperature of the transmitter / receiver 6 and the peak voltage of the received signal of the transmitter / receiver 6 is obtained in advance by experiments or the like. be able to.
Prior to the measurement of the propagation time by the propagation time measurement means 10, the peak voltage measurement means 26 transmits the drive pulse input from the drive unit 12 to the transceiver 6 on one side and transmits the transmitter / receiver on the other side. The maximum voltage of the received signal received from 6 before amplification is measured as the peak voltage.

  Then, the temperature deriving unit 27 refers to the correlation between the temperature of the transmitter / receiver 6 and the peak voltage obtained in advance, and uses the peak voltage of the received signal derived by the peak voltage measuring unit 26 to calculate the temperature. The temperature of the transceiver 6 can be derived.

When the temperature of the transceiver 6 derived by the temperature deriving unit 27 is below the set temperature range, the temperature setting unit 32 operates the heater 33 to set the temperature within the set temperature range. It is configured.
With this configuration, since the temperature of the transmitter / receiver 6 is maintained within the set temperature range, a change in the waveform of the received signal is prevented.
Therefore, the reference voltage used for determining the reception time point in the reception signal by the reception time point determination unit 14 of the propagation time measuring means 10 is appropriately set to a predetermined value by the reference voltage setting means 25. The first wave in the signal that exceeds the reference voltage is almost certainly the specific target wave from the reception time, and the zero-cross point and the reception time are accurately determined based on the time when the received signal in the target wave reaches the reference voltage. Therefore, an accurate propagation time is measured.

Here, the set temperature range means that even if the temperature of the transmitter / receiver 6 changes within the range, the waveform of the received signal in the transmitter / receiver 6 is substantially constant, and the reception time point determination unit 14 determines the reception time point. Is a temperature range that is substantially unaffected by changes in temperature.
For example, if the temperature of the transmitter / receiver 6 is within a range of 20 ° C. to 60 ° C., the waveform of the received signal is substantially constant and is not substantially affected by temperature, so that the temperature range is set as the set temperature range. Can do.

  Further, in the present apparatus, since the heater 33 is installed in the upstream space 3, the temperature of the transmitter / receiver 6 installed in the measurement channel 2 can be quickly raised to the set temperature range. The waiting time until the flow velocity value is derived can be shortened.

  Further, the temperature setting means 32 operates the heater 33 when the temperature of the transceiver 6 is below the set temperature range, and sets the temperature of the transmitter / receiver 6 to the lower limit value (for example, 20 ° C.) of the set temperature range. Is configured to set to Thereby, the energy required for temperature rise can be reduced while shortening the waiting time until the flow velocity value is derived.

  The reference voltage setting means 25 is a means for appropriately setting a reference voltage so that the reception time can be accurately determined. In the present embodiment, since the received signal is amplified by the amplifying unit 13 so as to maximize the set voltage, the reference voltage can be appropriately set corresponding to the set voltage.

  Next, a flow for actually deriving a flow velocity value using this apparatus will be described with reference to FIG.

  First, prior to the measurement of the propagation time by the propagation time measuring means 10, the peak voltage measuring means 26 in the control device 50 measures the maximum voltage of the received signal before amplification as the peak voltage (step # 1).

  Next, the temperature deriving means 27 in the control device 50 refers to the correlation between the temperature of the transceiver 6 and the peak voltage obtained in advance, and the correlation and the peak voltage measured by the peak voltage measuring means 26 are measured. Then, the temperature of the transceiver 6 is derived (step # 2).

  And the temperature setting means 32 in the control apparatus 50 confirms whether the temperature of the transmitter / receiver 6 is higher than the lower limit (for example, 20 degreeC) of a setting temperature range (step # 3), and the said temperature is a setting temperature range. If the temperature is higher than the lower limit value, the temperature setting means 32 stops the heater 33 (step # 4), derives the flow velocity value (step # 5), and the temperature of the transceiver 6 is the lower limit value of the set temperature range. If not, the temperature setting means 32 activates the heater 33 (step # 6) and executes the above steps # 1 to # 3 again. Therefore, after determining that the temperature of the transmitter / receiver 6 is higher than the lower limit value of the set temperature range in step # 3, the flow velocity value is derived in step # 5.

  Therefore, in the present apparatus, the propagation time is measured for deriving the flow velocity value after the temperature of the transmitter / receiver 6 becomes higher than the lower limit value of the predetermined set temperature range. Therefore, even when the reference voltage is set to a predetermined value, the wave that first exceeds the reference voltage in the received signal is almost certainly the specific target wave from the reception time, and the time when the received signal in the target wave reaches the reference voltage. The zero crossing point and the reception time point are accurately determined based on the reference, the accurate propagation time is measured, and an accurate flow velocity value can be derived.

[Another embodiment]
(1)
In the above embodiment, the temperature deriving unit 27 is configured to derive the temperature of the transmitter / receiver 6 based on the peak voltage of the received signal of the transmitter / receiver 6, but can be configured as follows. .

That is, this apparatus shown in FIG. 4 includes a sound speed calculation means 30 for deriving the sound speed in the measurement flow path 2 based on the measurement result of the propagation time measurement means 10, and the temperature deriving means 31 that the control device 51 functions is The temperature of the transmitter / receiver 6 is derived based on the speed of sound. Since the transmitter / receiver 6 is installed in the measurement channel 2, the temperature of the transmitter / receiver 6 is assumed to be the temperature in the measurement channel 2.
In the description of the apparatus shown in FIG. 4, the same components as those of the apparatus shown in FIG.

Since the sound velocity C in the measurement channel 2 is a function of the temperature Th of the transmitter / receiver 6 as shown in the following equation, if the sound velocity C is determined, the temperature Th of the transmitter / receiver 6 can be determined.
C = C1 + C2 · Th
However, C1 and C2 are constants.

The sound speed calculation means 30 can derive the sound speed C from, for example, the forward propagation time t1 and the reverse propagation time t2 measured immediately before by the propagation time measurement means 10 as shown in the following equation.
t1 = L / (C + v ′) = L / (C + v · cos θ)
t2 = L / (Cv ′) = L / (Cv · cos θ)
C = L · (1 / t1 + 1 / t2) / (2 · cos θ)

  The temperature deriving means 31 substitutes the sound speed C derived by the sound speed calculating means 30 into a function of the sound speed C and the temperature Th of the transmitter / receiver 6 to obtain the temperature Th of the transmitter / receiver 6. it can.

  Of course, the temperature deriving means 31 may be configured to directly derive the temperature of the transceiver 6 from the output of a temperature sensor installed in the vicinity of the transceiver 6.

(2)
In the above embodiment, the reception time point determination unit 14 determines the time point before the delay time from the zero cross point at which the reception signal after being amplified from the amplification unit 13 reaches the zero level immediately after reaching the reference voltage. The reception signal is determined in another form, for example, when the reception signal reaches a reference voltage or when the zero cross point itself is determined as the reception time. It can also be configured to determine the reception time of the ultrasonic wave of the transmitter / receiver 6 in comparison with the reference voltage.

(3)
In the above embodiment, the amplification unit 13 that amplifies the reception signal of the transmitter / receiver 6 so as to maximize the set voltage is provided. It does not matter if it is modified to be amplified or the amplifying unit 13 is omitted.
When the amplification unit is modified or omitted in this way, the reference voltage setting unit can set a voltage having a predetermined ratio with respect to the peak voltage of the reception signal of the transceiver as the reference voltage.

(4)
In the above embodiment, the fluid flowing in the measurement channel 2 is the gas g, but the present invention can naturally be applied even when another fluid flows.

(5)
In the said embodiment, although the temperature adjustment means was comprised by the heater 33, if the transmitter / receiver 6 can be heated, it can be used as a temperature adjustment means without a restriction | limiting in particular. For example, a resistance heater etc. are mentioned. Further, the temperature adjusting means may be configured to perform both heating and cooling in order to perform temperature adjustment with high accuracy.

(6)
In the above embodiment, the temperature adjusting means is provided in the upstream space 3, but the installation location is not particularly limited as long as the flow of the gas g and the transmission / reception of ultrasonic waves are not hindered.

  The ultrasonic meter device according to the present invention measures the propagation time of an ultrasonic wave in a fluid such as a gas flowing through a measurement flow path, and derives a flow velocity value related to the flow velocity such as a fluid flow velocity and a flow rate from the propagation time. The ultrasonic meter device can be effectively used as a device that can be simplified and reduced in price and can quickly and accurately derive a flow velocity value.

Schematic configuration diagram of an ultrasonic meter device of an embodiment Diagram showing the state of the received signal Flow chart for deriving flow velocity values in the embodiment Schematic configuration diagram of an ultrasonic meter device according to another embodiment

Explanation of symbols

1: Ultrasonic meter device 2: Measurement flow path 6, 6a, 6b: Ultrasonic transmitter / receiver 10: Propagation time measuring means 13: Amplifying unit (amplifying means)
14: reception time determination unit 20: flow velocity value calculating means 25: reference voltage setting means 26: peak voltage measuring means 27, 31: temperature deriving means 30: sonic speed calculating means 32: temperature setting means 33: heater (temperature adjusting means)
g: Gas (fluid)
t1, t2: propagation time C: speed of sound

Claims (7)

A pair of ultrasonic transceivers capable of mutually transmitting and receiving ultrasonic waves are installed on the upstream side and the downstream side of the measurement flow channel through which the fluid flows, and ultrasonic waves transmitted from one side of the pair of ultrasonic transceivers are transmitted. Propagation time measuring means for receiving on the other side and measuring the propagation time of ultrasonic waves between the pair of ultrasonic transceivers, and the flow rate of the fluid flowing through the measurement channel based on the measurement result of the propagation time measuring means A flow velocity value calculating means for deriving a flow velocity value, wherein the propagation time measuring means determines the reception time of the ultrasonic wave of the ultrasonic transceiver by comparing the received signal of the ultrasonic transceiver with a reference voltage. An ultrasonic meter device configured as follows:
Temperature deriving means for deriving the temperature of the ultrasonic transceiver;
Temperature adjusting means for adjusting the temperature of the ultrasonic transceiver;
An ultrasonic meter device comprising temperature setting means for controlling the temperature adjusting means based on a result derived by the temperature deriving means to set the temperature of the ultrasonic transceiver within a set temperature range. As the temperature adjustment means, comprising a heater capable of heating the ultrasonic transceiver,
2. The ultrasonic meter device according to claim 1, wherein the temperature setting unit operates the heater when the temperature of the ultrasonic transmitter / receiver derived by the temperature deriving unit falls below a set temperature range.   The ultrasonic meter device according to claim 2, wherein the temperature setting means sets the temperature of the ultrasonic transceiver to a lower limit value of a set temperature range. Comprising a peak voltage measuring means for measuring a peak voltage of a reception signal of the ultrasonic transceiver;
The ultrasonic meter device according to any one of claims 1 to 3, wherein the temperature deriving unit derives the temperature of the ultrasonic transceiver based on a peak voltage measured by the peak voltage measuring unit. A sound speed calculating means for deriving a sound speed in the measurement channel based on the measurement result of the propagation time measuring means;
The ultrasonic meter device according to any one of claims 1 to 3, wherein the temperature deriving unit derives the temperature of the ultrasonic transceiver based on the sound speed derived by the sound speed calculating unit.   The ultrasonic meter device according to any one of claims 1 to 5, further comprising an amplifying unit that amplifies a reception signal of the ultrasonic transceiver so as to maximize a set voltage.   The ultrasonic meter device according to claim 1, further comprising a reference voltage setting unit that sets the reference voltage to a voltage having a predetermined ratio with respect to a peak voltage of a reception signal of the ultrasonic transceiver.

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