JP5097293B2 - Ultrasonic meter device - Google Patents

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 that exceeds 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 the received signal of the ultrasonic transceiver and a reference voltage, the first characteristic configuration of which is to derive the usage time of the ultrasonic transceiver Usage time deriving means;
A reference voltage setting unit that sets the reference voltage based on a result derived by the usage time deriving unit is provided.

  As a result of diligent research, the inventors of the present application have determined that the ultrasonic transmitter / receiver usage time (ultrasonic wave) during ultrasonic transmission / reception is measured when measuring the propagation time of ultrasonic waves in a fluid such as a gas flowing through a measurement channel. It has been found that the change in the accumulated time of use since the start of use of the transceiver is the main factor that changes the waveform of the received signal of the ultrasonic transceiver. Furthermore, there is a certain correlation between the change in the usage time and the change in the waveform of the received signal. If the correlation is obtained in advance by experiments and the above usage time can be obtained, It has been found that the waveform of the received signal at the time of measurement can be estimated from the acquired usage time and the correlation obtained in advance, and the present invention has been completed.

That is, according to the first characteristic configuration, the usage time of the ultrasonic transmitter / receiver at the time of ultrasonic transmission / reception by the ultrasonic transmitter / receiver can be reduced by the configuration capable of being simplified and reduced in price by including the usage time deriving unit. Can be derived. Further, the reference voltage setting means determines the reference voltage used for determining the reception time point in the received signal by the propagation time measuring means based on the derivation results of the derivation means, that is, the usage time of the ultrasonic transceiver. Therefore, it is possible to quickly set an optimum one according to the waveform of the received signal.
Therefore, in determining the reception time of the ultrasonic wave of the ultrasonic transmitter / receiver by the propagation time measuring unit by comparing the reception signal of the ultrasonic transmitter / receiver and the optimum reference voltage set by the reference voltage setting unit, The first wave in the received signal that exceeds the reference voltage can be almost certainly the specific target wave from the reception time, so the reception time is based on the time when the received signal in the target wave reaches the reference voltage. Can be accurately determined, and an accurate propagation time can be measured.
Therefore, the optimum reference voltage is quickly set by a configuration that can be simplified and reduced in price, and the propagation time of the ultrasonic wave in the fluid such as the gas flowing through the measurement channel is accurately measured. Based on the propagation time, it is possible to realize an ultrasonic meter device that accurately derives a flow velocity value related to the flow velocity of the fluid flowing through the measurement channel.

  Further, the second characteristic configuration of the ultrasonic meter device according to the present invention is, in addition to the first characteristic configuration, an amplification means for amplifying the reception signal of the ultrasonic transmitter / receiver to maximize the set voltage. And the reference voltage setting means sets the reference voltage to a higher side as the operating time of the ultrasonic transceiver is longer.

That is, according to the second 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 generally small, the reception signal is amplified. By amplifying by means, 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.
Also, the longer the operating time of the ultrasonic transmitter / receiver, the weaker the received signal of the ultrasonic transmitter / receiver is. However, on the contrary, the received signal is amplified by the amplifying means to maximize the set voltage. If it does, the maximum voltage of the wave just before a target wave will rise. Therefore, by setting the reference voltage to the higher side in accordance with the increase in the maximum voltage of the wave immediately before the target wave in the received signal by the reference voltage setting means, the set reference voltage is set to the target in the received signal. As an optimum one in which the wave almost certainly exceeds the first, the flow velocity value related to the flow velocity of the fluid flowing through the measurement channel can be derived with high accuracy.

  According to a third characteristic configuration of the ultrasonic meter device according to the present invention, in addition to the first characteristic configuration, the reference voltage setting unit sets the reference voltage to a peak voltage of a reception signal of the ultrasonic transceiver. The voltage is set to a predetermined ratio and the ratio of the reference voltage to the peak voltage is increased as the operating time of the ultrasonic transceiver is longer.

In other words, according to the third feature 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.
In addition, the longer the operating time of the ultrasonic transmitter / receiver, the weaker the received signal of the ultrasonic transmitter / receiver is, but conversely, the ratio of the maximum voltage of the wave immediately before the target wave to the peak voltage increases. . Therefore, the reference voltage setting means increases the ratio of the reference voltage to the peak voltage by increasing the ratio of the maximum voltage of the wave immediately before the target wave to the peak voltage, thereby setting the ratio to the peak voltage. As a result, the flow velocity value relating to the flow velocity of the fluid flowing through the measurement flow path can be derived with high accuracy by using the reference voltage as the optimum one that the target wave in the received signal almost certainly first exceeds.

Schematic configuration diagram of an ultrasonic meter device of an embodiment Diagram showing the state of the received signal Graph showing the relationship of the set reference voltage to the temperature of the ultrasonic transceiver Graph showing the relationship of the set reference voltage to the usage time of the ultrasonic transceiver The graph which shows the relationship of the setting reference voltage with respect to the temperature of an ultrasonic transmitter / receiver for every classification of the usage time of an ultrasonic transmitter / receiver The graph which shows the relationship of the setting reference voltage with respect to the usage time of an ultrasonic transmitter / receiver for every classification of the temperature of an ultrasonic transmitter / receiver Schematic configuration diagram of an ultrasonic meter device according to another embodiment

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.

  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 described later. It functions as various means such as means 20, reference voltage setting means 25, temperature deriving means 27, usage time deriving means 29, 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 transmission of a driving pulse and reception of a received 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 measures the ultrasonic wave propagation time between the pair of transmitter / 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 obtains a zero cross point at which the reception signal amplified by the amplification unit 13 reaches a zero level immediately after reaching a predetermined reference voltage. The time point before a predetermined delay time set in advance 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.
In order to stabilize the strength of the received signal after amplification of the transceiver, the amplifying unit 13 maximizes the preset set voltage for the received signal of the transceiver 6 input through the switching unit 11. 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. The waveform of the received signal changes due to the change in temperature of the transmitter / receiver 6 and the change in the usage time of the transmitter / receiver 6. In determining by comparing the received signal of the transceiver 6 with the reference voltage, 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 The time may not be accurately determined.

  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 The control device 50 functions as a usage time deriving unit 29 for deriving 6 usage times, and a reference voltage setting unit 25 for setting a reference voltage based on the derived results of the temperature deriving unit 27 and the usage time deriving unit 29. The detailed configuration will be described below.

  A peak voltage measuring unit 26 that measures a peak voltage of a reception signal before amplification in the transceiver 6 input to the amplifying unit 13 as an amplifying unit is provided. The temperature deriving unit 27 performs transmission / reception based on the peak voltage. The temperature of the vessel 6 is derived.

That is, using 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.

  On the other hand, the use time deriving means 29 refers to the time measured by the timer 28 and starts using the present apparatus, or after using the transmitter / receiver 6 for a new product, the use time up to the present time. Is derived as the usage time of the transceiver 6.

  The reference voltage setting means 25 then determines the propagation time measuring means 10 based on the derivation results of the temperature deriving means 27 and the usage time deriving means 29, that is, the temperature of the transceiver 6 and the usage time of the transceiver 6. The reference voltage used to determine the reception time point in the reception signal by the reception time point determination unit 14 is quickly set to an optimum set reference voltage that matches the waveform of the reception signal.

Specifically, if the usage time of the transceiver 6 is constant, for example, the reference voltage setting means 25 has a low temperature Th of the transceiver 6 derived by the temperature deriving means 27 as shown in FIG. The maximum voltage of the wave immediately before the target wave in the amplified received signal rises as it increases, and the set reference voltage is shifted to the higher side in accordance with the increase.
Further, when the temperature Th of the transmitter / receiver 6 is equal to or higher than a predetermined temperature Th2 (for example, 20 ° C.), the waveform of the received signal is substantially constant, and therefore the set reference voltage can be set to a constant value. .

  On the other hand, when the temperature of the transceiver 6 is constant, for example, the reference voltage setting means 25 has a longer usage time Ti of the transceiver 6 derived by the usage time deriving means 29 as shown in FIG. Since the maximum voltage of the wave immediately before the target wave in the amplified received signal increases, the set reference voltage is shifted to a higher side in accordance with the increase.

Specifically, as shown in FIG. 5, the usage time Ti of the transmitter / receiver 6 has a plurality of ranges (a range of Ti0 or more and less than Ti1, a range of Ti1 or more and less than Ti2, a range of Ti2 or more and less than Ti3, a range of Ti3 or more and less than Ti4. Etc.), and for each of the classifications, an optimum correlation of the set reference voltage with respect to the temperature Th of the transmitter / receiver 6 is obtained in advance through experiments or the like.
The reference voltage setting means 25 specifies the classification of the usage time Ti of the transmitter / receiver 6 derived by the usage time deriving means 29, and then refers to the correlation previously obtained in the classification. The optimum setting reference voltage can be derived from the temperature of the transmitter / receiver 6 derived by the temperature deriving means 27, and the reference voltage used in the reception time determination unit 14 can be set as the setting reference voltage.

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 set by the reference voltage setting means 25 to the optimum set reference voltage. The first wave in the received signal that exceeds the set reference voltage is almost certainly the specific target wave from the reception time, and the zero cross point and the reception time are determined based on the time when the received signal in the target wave reaches the reference voltage. It is determined accurately and the accurate propagation time is measured.
Moreover, in this embodiment, since the reference voltage is set based on both the temperature of the transmitter / receiver 6 and the usage time of the transmitter / receiver 6, compared with the case where the reference voltage is set based on one, the reference voltage is more It becomes the most suitable for the waveform of the received signal.

[Another embodiment]
(1) In the above-described embodiment, the reference voltage setting means 25 is configured so that the optimum setting reference voltage correlates with the temperature Th of the transmitter / receiver 6 for each class of use time Ti of the transmitter / receiver 6 as shown in FIG. The reference voltage is set based on the derived results of the temperature deriving means 27 and the usage time deriving means 29. Alternatively, the reference voltage setting means 25 may be configured as follows. it can.

  That is, as shown in FIG. 6, the temperature Th of the transmitter / receiver 6 is classified into a plurality of ranges (a range of Th0 or more and less than Th1, a range of Th1 or more and less than Th2, Th2 or more, etc.). The optimum correlation of the set reference voltage with respect to the usage time Ti is obtained in advance by experiments or the like. In this embodiment, in the classification of the temperature Th of the transmitter / receiver 6, the set reference voltage equal to or higher than the predetermined temperature Th2 is made constant and the predetermined temperature Th2 or higher is set as one classification. A plurality of classifications may be set finely in the range.

  The reference voltage setting means 25 specifies the classification of the temperature Th of the transmitter / receiver 6 derived by the temperature deriving means 27 and then refers to the correlation previously obtained in the classification, The optimum set reference voltage can be derived from the use time Ti of the transceiver 6 derived by the use time deriving means 29, and the reference voltage used in the reception time determination unit 14 can be set as the set reference voltage.

  The correlation of the set reference voltage with respect to the temperature Th of the transmitter / receiver 6 and the usage time of the transmitter / receiver 6 is obtained in advance, and the reference voltage setting means 25 is derived by the temperature deriving means 27 with reference to the correlation. The optimum setting reference voltage is derived from the temperature Th of the transmitter / receiver 6 and the use time Ti of the transmitter / receiver 6 derived by the use time deriving means 20, and the reference voltage used by the reception time determination unit 14 is set. It can also be configured to set the reference voltage.

(2) 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 separately configured as follows. You can also.

That is, this apparatus shown in FIG. 7 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. 7, the same components as those of the apparatus shown in FIG.

Since the sound velocity C in the measurement channel is a function of the temperature Th of the transmitter / receiver 6 as shown in the following equation, if the sound velocity C is obtained, the temperature Th of the transmitter / receiver 6 can be obtained.
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)

  Then, 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 transceiver 6 to obtain the temperature Th of the transceiver 6. it can.

  Of course, the temperature deriving means 31 may be configured to directly derive the temperature of the transmitter / receiver 6 based on the output of a temperature sensor installed in the vicinity of the transmitter / receiver 6.

(3) In the above embodiment, the reception time determination unit 14 is delayed by the delay time from the zero cross point at which the reception signal after being amplified by the amplification unit 13 reaches the zero level immediately after reaching the reference voltage. However, in another form, for example, when the received signal reaches a reference voltage or the zero cross point itself is determined as the reception time point, The reception signal may be compared with a reference voltage to determine the reception time point of the ultrasonic wave of the transceiver 6.

(4) In the above embodiment, the amplifying unit 13 is provided that amplifies the received signal of the transceiver 6 so that the set voltage is maximized. It may be modified to amplify with or the amplifying unit may be omitted.
Further, when the amplifying unit is modified or omitted in this way, the reference voltage setting means receives the reference voltage when setting a voltage having a predetermined ratio with respect to the peak voltage of the reception signal of the transceiver as the reference voltage. In order to ensure that the target wave is optimally exceeded first in the signal, the peak of the received signal of the transmitter / receiver 6 becomes lower as the temperature of the transmitter / receiver 6 is lower or the usage time of the transmitter / receiver 6 is longer. The ratio of the reference voltage set with respect to the voltage may be reduced, and the reference voltage may be set on the higher side.

(5) In the above embodiment, the reference voltage setting unit 25 is based on both the temperature of the transceiver 6 derived by the temperature deriving unit 27 and the usage time of the transceiver 6 derived by the usage time deriving unit 29. However, the temperature deriving unit may be omitted and the reference voltage setting unit 25 may be configured to set the reference voltage based on the usage time of the transceiver. I do not care.

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

  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. It is an ultrasonic meter device, which can be simplified and inexpensive, and can be effectively used as a device capable of deriving a flow velocity value quickly and accurately.

1: Ultrasonic meter device 2: Measurement flow path 6, 6a, 6b: Ultrasonic transmitter / receiver 10: Propagation time measurement means 14: Reception time determination unit 20: Flow rate value calculation means 25: Reference voltage setting means 26: Peak voltage Measuring means 29: Usage time deriving means 30: Sonic speed calculating means 50, 51: Control device g: Gas (fluid)
t1, t2: propagation time C: speed of sound

Claims (3)

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:
Usage time deriving means for deriving the usage time of the ultrasonic transceiver;
An ultrasonic meter device comprising reference voltage setting means for setting the reference voltage based on a result derived by the use time deriving means. Amplifying means for amplifying the reception signal of the ultrasonic transmitter / receiver to a maximum set voltage,
The ultrasonic meter device according to claim 1, wherein the reference voltage setting unit sets the reference voltage to a higher side as the usage time of the ultrasonic transceiver is longer.   The reference voltage setting means sets the reference voltage to a voltage of a predetermined ratio with respect to a peak voltage of a reception signal of the ultrasonic transceiver, and the longer the usage time of the ultrasonic transceiver is, the longer the reference voltage is The ultrasonic meter device according to claim 1, wherein a ratio with respect to a peak voltage is increased.

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