JP6602247B2 - Ultrasonic meter and control method thereof - Google Patents

Description

  The present invention allows ultrasonic waves to propagate in a first direction along the flow direction and a second direction opposite to the first direction with respect to the flow direction of the gas flowing through the gas flow path, A pair of transducers for receiving the ultrasonic wave propagating the predetermined propagation distance in the first direction and receiving the ultrasonic wave propagating the predetermined propagation distance in the second direction; and the ultrasonic wave in the first direction The first propagation time that propagates the predetermined propagation distance and the second propagation time that the ultrasonic wave propagates through the predetermined propagation distance in the second direction are measured, and the measured first propagation time and second propagation time are measured. And a control unit for deriving a gas flow velocity of the gas flowing through the gas flow path from the predetermined propagation distance, and the control unit determines the transmission intensity of the ultrasonic waves transmitted by the pair of transducers. The ultrasonic reception intensity received by the transducer is the target reception intensity. With adjusted to, ultrasonic meter determines the ultrasonic transmission and reception state when the transmission intensity is adjusted exceeds an abnormality determination threshold value is in an abnormal state, and a control method thereof.

Conventionally, as an ultrasonic meter, ultrasonic waves propagate in a first direction along the flow direction and a second direction opposite to the first direction with respect to the flow direction of the gas flowing through the gas flow path. A pair of transducers for receiving the ultrasonic wave propagated through the predetermined propagation distance in the first direction and receiving the ultrasonic wave propagated through the predetermined propagation distance in the second direction, and having the predetermined propagation distance in the first direction. The first propagation time during which the ultrasonic wave propagates and the second propagation time during which the ultrasonic wave propagates through the predetermined propagation distance in the second direction, and the measured first propagation time, second propagation time, and predetermined propagation distance A gas flow rate of a gas flowing through a gas flow channel is derived from the gas flow rate, and a control unit for deriving a gas flow rate from the gas flow rate and the flow channel cross-sectional area of the gas flow channel is known (Patent Document) 1).
In the ultrasonic meter disclosed in Patent Document 1, the control unit determines the transmission intensity of the ultrasonic wave transmitted by the pair of transducers, and the reception intensity of the ultrasonic wave received by the pair of transducers is the target reception intensity. What adjusts automatically so that it may become is known (refer patent document 2).
As described above, in an ultrasonic meter that automatically adjusts transmission intensity, it is known that the transmission intensity abnormally increases when water droplets, dust, or the like is present in the propagation region in which the ultrasonic wave propagates.
In this way, when the transmission intensity is abnormally increased, there is a risk of failure of the ultrasonic meter, and when the ultrasonic meter fails, there is a problem from the viewpoint of safety because an accurate gas flow rate cannot be measured. For this reason, in the above-mentioned ultrasonic meter, when the transmission intensity of the automatically adjusted ultrasonic wave exceeds a predetermined abnormality determination threshold value, the transmission / reception state of the ultrasonic wave is abnormal. If it is determined that there is an abnormal condition, and if it is determined that there is an abnormal condition, control for issuing a transmission intensity amplification abnormality alarm is executed, or the cutoff valve provided in the gas passage is abnormally shut off. It is configured to execute control.

JP 2005-337726 A JP 2005-257359 A

The gas composition-related values (specifically, gas type, gas composition, heat quantity, average molecular weight) of the gas flowing through the gas flow path in which the ultrasonic meter is installed change over time. In some cases, for example, the city gas 13A having a low calorific value (42 MJ / m ³ ) may be supplied in addition to the city gas 13A having a normal calorific value (45 MJ / m ³ ).
And now, the inventors of the present application have made extensive investigations, and when the gas composition-related value of the gas flowing through the gas flow path fluctuates, We found a new finding that the transmission strength fluctuates. As described above, when the transmission intensity of the automatically adjusted ultrasonic wave fluctuates, there is no abnormality in the transmission / reception state of the ultrasonic wave, that is, the transmission intensity is amplified even though there is no dust or water drop in the ultrasonic wave propagation region. There is a possibility that an abnormal alarm is issued or the gas passage is abnormally blocked.

  The present invention has been made in view of the above-described problems, and its purpose is to amplify the transmission intensity of ultrasonic waves caused by fluctuations in gas composition-related values (gas species, gas composition, heat quantity, average molecular weight). Highly versatile that can be used appropriately when gas composition-related values fluctuate because it can prevent abnormal alarms from being issued and abnormal shut-off of gas flow paths due to fluctuations in gas composition-related values. An ultrasonic meter and a control method thereof are provided.

An ultrasonic meter for achieving the above object is
An ultrasonic wave propagates in a first direction along the flow direction and a second direction opposite to the first direction with respect to the flow direction of the gas flowing through the gas flow path, and the first direction A pair of transducers for receiving the ultrasonic wave propagated through the predetermined propagation distance and receiving the ultrasonic wave propagated through the predetermined propagation distance in the second direction,
The first propagation time in which the ultrasonic wave propagates through the predetermined propagation distance in the first direction and the second propagation time in which the ultrasonic wave propagates through the predetermined propagation distance in the second direction are measured and measured. A controller for deriving a gas flow velocity of the gas flowing through the gas passage from the propagation time and the second propagation time and the predetermined propagation distance;
The control unit adjusts the transmission intensity of the ultrasonic waves transmitted by the pair of transducers so that the reception intensity of the ultrasonic waves received by the pair of transducers becomes a target reception intensity. An ultrasonic meter that determines that the transmission / reception state of an ultrasonic wave is in an abnormal state when the transmission intensity exceeds an abnormality determination threshold, the characteristic configuration is
The said control part exists in the point which changes and sets the said abnormality determination threshold value based on the gas composition related value of the gas which flows through the said gas flow path.

The control method of the ultrasonic meter for achieving the above object is as follows:
An ultrasonic wave propagates in a first direction along the flow direction and a second direction opposite to the first direction with respect to the flow direction of the gas flowing through the gas flow path, and the first direction A pair of transducers for receiving the ultrasonic wave propagated through the predetermined propagation distance and receiving the ultrasonic wave propagated through the predetermined propagation distance in the second direction,
Measuring a first propagation time for ultrasonic waves to propagate through the predetermined propagation distance in the first direction and a second propagation time for ultrasonic waves to propagate through the predetermined propagation distance in the second direction; Deriving the gas flow velocity of the gas flowing through the gas flow path from the propagation time that is the second propagation time and the predetermined propagation distance,
A method of controlling an ultrasonic meter that adjusts the transmission intensity of ultrasonic waves transmitted by the pair of transducers and determines that the gas flow state is in an abnormal state when the transmission intensity exceeds an abnormality determination threshold value And the characteristic composition is
The abnormality determination threshold value is changed and set based on the gas composition related value of the gas flowing through the gas flow path.

As described above, the inventors of the present application adjust in the ultrasonic meter when the gas composition-related values (gas species, gas composition, calorific value, average molecular weight, etc.) flowing through the gas flow path change. A new finding was found that the transmission intensity of ultrasonic waves fluctuated. When the explanation is added, it is understood that the city gas 13A having a low calorific value (42 MJ / m ³ ) tends to have a higher ultrasonic transmission intensity than the city gas 13A having a normal calorific value (45 MJ / m ³ ). I found it.
According to the above configuration, the control unit changes the abnormality determination threshold value for determining whether there is an abnormality in the ultrasonic transmission / reception state based on the gas composition related value of the gas flowing through the gas passage. Since it is comprised, even when the gas composition related value flowing through the gas passage changes, the abnormality determination threshold value can be changed to an appropriate value corresponding to the change.
For example, when the gas changes from normal heat (45 MJ / m ³ ) to low heat (42 MJ / m ³ ), the transmission intensity increases. It is possible to prevent the occurrence of an abnormal amplification alarm due to fluctuations and the abnormal shutoff of the gas passage due to fluctuations in the gas composition related values.
As a result, an abnormal alarm for the transmission intensity of ultrasonic waves caused by fluctuations in gas composition-related values (gas species, gas composition, calorie, average molecular weight) and gas caused by fluctuations in gas composition-related values It is possible to provide a versatile ultrasonic meter that can be prevented from being abnormally blocked in the flow path and can be appropriately used even when the gas composition related value fluctuates, and a control method therefor.

Further features of the ultrasonic meter
The said control part exists in the point which changes to the said abnormality determination threshold value, so that the calorie | heat amount corresponding to the said gas composition related value is low.

  That is, the inventors of the present application change the gas composition related value of the gas flowing through the gas flow path by changing to a higher abnormality determination threshold as the amount of heat corresponding to the gas composition related value is lower. Even so, we have completed an ultrasonic meter that can properly determine whether or not the ultrasonic transmission / reception state is in an abnormal state, excluding the influence of changes in transmission intensity due to fluctuations in the gas composition related value. is there.

Further features of the ultrasonic meter
A storage unit that stores a first relationship that is a relationship between the propagation time that is the first propagation time or the second propagation time and the gas composition-related value;
The control unit is configured to derive the gas composition related value of the gas flowing through the gas flow path based on the measured propagation time and the first relationship.

The inventors of the present application have found that the propagation time which is the first propagation time or the second propagation time of the ultrasonic wave is related to the gas composition related value. For example, as shown in the tables of [Table 1] and [Table 2] described later, the propagation time of the city gas 13A with a low calorific value (42 MJ / m ³ ) is the same as that of the city gas 13A with a normal calorific value (45 MJ / m ³ ). It has been found that at least 15 μs or more (the rate of change is about 10% or more) is smaller than the propagation time.
According to the above characteristic configuration, the first relationship, which is the relationship between the propagation time of the ultrasonic wave and the gas composition related value, is, for example, a table format (as shown in [Table 1] and [Table 2] described later) By including a storage unit that holds in a functional format, and a control unit that derives a gas composition related value of the gas flowing from the propagation time and the first relationship that is the first propagation time or the second propagation time, A gas composition related value can be derived well without greatly changing the device configuration of a conventional ultrasonic meter. And the abnormality determination threshold value can be favorably changed in a form corresponding to the derived gas composition related value.

The first propagation time t1 of the ultrasonic wave along the first direction d1 and the second propagation time t2 of the ultrasonic wave along the second direction d2 are a predetermined propagation distance through which the ultrasonic wave propagates as shown in FIG. L (m), sound velocity C (m / s), gas flow velocity V (m / s), and the angle between the gas flow direction and the first and second directions in which the ultrasonic wave propagates is θ (° ), The following relationships are expressed by [Formula 1] and [Formula 2].
t1 = L / (C + V · cos θ) (Equation 1)
t2 = L / (C−V · cos θ) (Equation 2)

As can be seen from the above [Expression 1] and [Expression 2], the propagation time of the ultrasonic wave also depends on the flow velocity of the gas. However, the rate of change of the propagation time of the ultrasonic wave due to the change of the gas flow velocity is such that the predetermined propagation distance of the ultrasonic meter is about 70 mm, the fluctuation of the gas flow velocity is about 0 to 5.5 m / sec, and the sound velocity C is 340 m. Assuming that the mounting angle θ is a general value of about 40 ° / sec, the rate of change of the propagation time when the gas flow velocity changes from 0 to 5.5 m / sec is about 1.2% at most. The rate of change in propagation time when the gas calorie fluctuates between the city gas 13A having a low calorific value (42 MJ / m ³ ) and the city gas 13A having a normal calorific value (45 MJ / m ³ ) (about 10% or more) ), The change is sufficiently small and can be ignored.

  That is, according to the ultrasonic meter having the above-described characteristic configuration, the first propagation time or the second propagation time sequentially derived by the ultrasonic meter regardless of the flow velocity of the gas flowing through the gas passage. Based on a certain propagation time, the gas composition related value can be appropriately derived.

Further features of the ultrasonic meter
The storage unit stores a second relationship that is a relationship between the gas composition related value and the abnormality determination threshold value,
The control unit extracts the abnormality determination threshold corresponding to the gas composition related value based on the derived gas composition related value and the second relationship, and changes and sets the extracted abnormality determination threshold. is there.

According to the above characteristic configuration, since the storage unit also stores the second relationship between the gas composition related value and the abnormality determination threshold value, the control unit determines from the derived gas composition related value and the fourth relationship, The abnormality determination threshold value corresponding to the gas composition related value can be appropriately extracted, and the abnormality determination threshold value can be appropriately changed and set to the abnormality determination threshold value corresponding to the gas composition related value.
Thereby, determination of the abnormal state of an ultrasonic meter can be performed appropriately based on the abnormality determination threshold value appropriately corresponding to the gas composition related value of the gas flowing through the gas passage.

Further features of the ultrasonic meter
Comprising temperature measuring means for measuring the temperature of the gas flowing through the gas flow path,
The ultrasonic velocity transmitted and received by the pair of transducers, the average molecular weight as the gas composition related value of the gas flowing through the gas passage, and the gas passage A storage unit that stores a third relationship that is a relationship that the temperature of the gas has;
The control unit derives the sound velocity of the ultrasonic wave from the propagation time which is the first propagation time or the second propagation time and the predetermined propagation distance, and the derived sound velocity and the temperature measured by the temperature measuring unit. From the third relation, the average molecular weight as the gas composition related value of the gas is derived.

According to the above characteristic configuration, the average molecular weight of the gas can be favorably adopted as the gas composition related value.
That is, using the first propagation time t1 and the second propagation time t2 derived from the above-described [Expression 1] and [Expression 2], the sound velocity C of the ultrasonic wave can be expressed by the following [Expression 3]. it can.
C = L / 2 · (1 / t1 + 1 / t2) (Equation 3)
Although a detailed description is omitted, for each temperature of the ultrasonic propagation medium (in this specification, gas), the sound velocity C derived by [Equation 3] and the average molecular weight of the propagation medium are linearly correlated. Relationship or quadratic correlation.
In the above characteristic configuration, the primary correlation or the secondary correlation for each temperature is stored in the storage unit as a third relationship, the derived sound speed C, the temperature measured by the temperature measuring means, From the third relationship, the average molecular weight of the propagation medium (gas) can be derived.

Further features of the ultrasonic meter
The storage unit stores a fourth relationship that is a relationship between the average molecular weight and the abnormality determination threshold,
The control unit is configured to extract the abnormality determination threshold corresponding to the average molecular weight based on the average molecular weight of the derived gas and the fourth relationship, and change and set the extracted abnormality determination threshold.

According to the above characteristic configuration, since the storage unit also stores the fourth relationship between the average molecular weight and the abnormality determination threshold value, the control unit corresponds to the average molecular weight from the derived average molecular weight and the fourth relationship. The abnormality determination threshold value to be extracted can be appropriately extracted, and the abnormality determination threshold value can be appropriately changed and set to the abnormality determination threshold value corresponding to the average molecular weight.
Thereby, determination of the abnormal state of an ultrasonic meter can be performed appropriately based on the abnormality determination threshold value appropriately corresponding to the average molecular weight of the gas flowing through the gas passage.

Further features of the ultrasonic meter
The control unit is electrically connected to an external server provided outside via a communication network,
The external server is configured to sequentially update and store the gas composition related values of the gas flowing through the gas flow path in which the pair of transducers are provided,
A storage unit that stores a second relationship that is a relationship between the gas composition-related value and the abnormality determination threshold;
The controller is configured to be able to acquire the gas composition related value from the external server, and based on the acquired gas composition related value and the second relationship, the abnormality corresponding to the gas composition related value The determination threshold value is extracted and changed to the extracted abnormality determination threshold value.

In the ultrasonic meter of the present invention, the gas composition related value of the gas passing through itself can be obtained from an external server provided outside, as in the above-described characteristic configuration, Using the acquired gas composition-related value and the second relationship, an abnormality determination threshold corresponding to the gas composition-related value can be extracted and changed to the extracted abnormality determination threshold.
For example, the ultrasonic meter is configured to receive from the external server the timing at which the gas composition related value is switched at the gas factory that sends the gas, in addition to the gas composition related value switched at the factory. be able to. Furthermore, based on the length of the gas conduit from the manufacturing site to the installation location of the ultrasonic meter and the gas flow rate, the time when the gas related to the switched gas composition related value reaches the installation location of the ultrasonic meter is derived. Can be configured to The ultrasonic meter can update and record the gas composition related value at an appropriate time when the gas related to the gas composition related value reaches itself by updating the gas composition related value at the derived time.

Schematic configuration diagram of an ultrasonic meter according to the first embodiment Schematic configuration diagram of an ultrasonic meter according to the second embodiment Schematic configuration diagram of an ultrasonic meter according to the third embodiment

  In the ultrasonic meter according to the embodiment, the ultrasonic transmission intensity amplification anomaly alarm and the gas composition related value due to the fluctuation of the gas composition related value (gas type, gas composition, calorie, average molecular weight) of the gas. The present invention relates to a highly versatile ultrasonic meter that can prevent the abnormal shutoff of the gas passage due to the fluctuation of the gas from being performed and can be appropriately used even when the gas composition related value fluctuates, and a control method thereof. Hereinafter, embodiments of the ultrasonic meter and a control method thereof will be described based on the drawings.

[First Embodiment]
As shown in FIG. 1, the ultrasonic meter 100 according to the present embodiment is in a flow direction (a direction along arrow g in FIG. 1) of a gas (for example, city gas 13 </ b> A) that flows through the gas passage 11. On the other hand, the ultrasonic wave propagated in the first direction d1 along the flow direction and the second direction d2 opposite to the first direction and propagated through the predetermined propagation distance L in the first direction d1. A first propagation that includes a pair of transducers 10a and 10b that receive and receive an ultrasonic wave that has propagated a predetermined propagation distance L in the second direction d2 and that propagates the predetermined propagation distance L in the first direction d1. The time t1 and the second propagation time t2 in which the ultrasonic wave propagates through the predetermined propagation distance L in the second direction are measured, and the measured first propagation time t1 and second propagation time t2 are measured from the predetermined propagation distance L as a gas. Deriving the gas flow velocity of the gas flowing through the flow path 11 And a control unit C (an example of a control unit) to derive the flow rate of gas flowing through the gas flow path 11 from the gas flow rate.

When the description is added, the control device C has, as a basic configuration, a central control unit C1 that controls the entire ultrasonic meter 100, and a transmitter / receiver control unit C2 that controls transmission and reception of ultrasonic waves in the transducers 10a and 10b. A transmission intensity amplifying unit C3 for amplifying the ultrasonic transmission intensity at the transducers 10a and 10b so that the ultrasonic reception intensity at the transducers 10a and 10b becomes an appropriate intensity; A propagation time measurement unit C4 that measures the first propagation time t1 and the second propagation time t2, and a flow velocity that derives the gas flow velocity of the gas flowing through the gas flow path 11 from the propagation time measured by the propagation time measurement unit C4. A deriving unit C5 and a flow rate deriving unit C6 for deriving a gas flow rate flowing through the gas flow path 11 from the gas flow rate derived by the flow rate deriving unit C5 are provided.
In executing the flow rate derivation control, the central control unit C1 instructs the transducer control unit C2 to drive the transducers 10a and 10b so as to drive the transducers 10a and 10b. Instruct the counting command to (not shown).
Upon receiving the drive command, the transmitter / receiver control unit C2 transmits a transmission signal that causes each of the transmitter / receivers 10a and 10b to transmit an ultrasonic wave, and propagates a reception signal that the transmitter / receiver 10a and 10b receives the ultrasonic wave. It transmits to the time measurement part C4.
The zero cross detection circuit (not shown) as the propagation time measurement unit C4 that receives the reception signal from the transmitter / receiver control unit C2 detects the reception timing and stops the counting in the counting circuit as the propagation time measurement unit C4. . That is, the time counted by the counting circuit as the propagation time measuring unit C4 becomes the first propagation time t1 or the second propagation time t2.
The transmission signal for transmitting the ultrasonic waves of the transducers 10a and 10b from the transducer control unit C2 has a value (for example, the voltage value of the signal) related to the transmission intensity of the transducers 10a and 10b. Yes. The transmitter / receiver control unit C2 relates to the transmission intensity of the transmission signal of the transmitter / receiver 10a, 10b in the transmission intensity amplifying unit C3 so that the ultrasonic wave reception intensity of the transmitter / receiver 10a, 10b becomes an appropriate intensity. After a value to be amplified is amplified, the transmission signal is transmitted to the transducers 10a and 10b.

As shown in FIG. 1, the first propagation time t1 and the second propagation time t2 measured by the propagation time measuring unit C4 are L (m) for the predetermined propagation distance through which the ultrasonic wave propagates, and C (m / s), when the gas flow velocity is V (m / s) and the angle between the gas flow direction and the first direction and the second direction in which the ultrasonic wave propagates is θ (°), the following [Equation 1], [ It has the relationship shown by Formula 2].
t1 = L / (C + V · cos θ) (Equation 1)
t2 = L / (C−V · cos θ) (Equation 2)

  Therefore, the flow velocity deriving unit C5 derives the gas flow velocity V in a form in which the above [Formula 1] and [Formula 2] are coupled, and the flow rate deriving unit C6 is configured to connect the derived gas flow velocity V to the gas flow path 11. The gas flow rate is derived in the form of integrating the flow path cross-sectional area S. The central control unit C1 displays the gas flow rate derived by the flow rate deriving unit C6 on the display unit 21 such as a counter so as to be visible from the outside.

Here, it is known that when dust, water droplets, and the like exist in the propagation path through which the ultrasonic wave propagates, the transmission intensity abnormally increases due to the presence of such dust and water droplets. As described above, when the transmission intensity is abnormally increased, there is a risk of failure of the ultrasonic meter (particularly, failure of the pair of transducers 10a and 10b), and an accurate gas flow rate when the ultrasonic meter fails. May not be measured, which is problematic from the viewpoint of safety.
Therefore, in the ultrasonic meter 100 according to the embodiment, it is determined that the ultrasonic transmission / reception state of the pair of transducers 10a and 10b is in an abnormal state based on the transmission intensity obtained from the transmission intensity amplification unit C3. A transmission strength abnormality determination unit C7, a transmission strength abnormality determination unit C7 that outputs a warning output command to the alarm device 22 when the transmission / reception state is determined to be abnormal, and a transmission strength abnormality determination unit When C7 determines that the transmission / reception state is an abnormal state, an abnormal cutoff control unit C9 that outputs a cutoff command to a cutoff valve (not shown) that shuts off the gas passage 11 is provided.
When the explanation is added, the transmission intensity abnormality determination unit C7 sets the transmission / reception state to an abnormal state at the alarm output level when the transmission intensity exceeds an alarm output abnormality determination threshold (an example of an abnormality determination threshold) for outputting an alarm. It is determined that there is, and the alarm output control unit C8 outputs an alarm output command to the alarm device 22. Further, the transmission intensity abnormality determination unit C7 exceeds the gas flow path blocking abnormality determination threshold value (an example of the abnormality determination threshold value: a threshold value higher than the alarm output abnormality determination threshold value) for blocking the shutoff valve. In this case, it is determined that the transmission / reception state is an abnormal state at the gas flow path cutoff level, and the abnormal cutoff control unit C9 outputs a cutoff command to the cutoff valve.

Furthermore, the inventors of the present application have a new finding that the transmission intensity of the ultrasonic wave varies even when the gas type (an example of the gas composition related value) of the gas flowing through the gas passage 13 changes. I found it. When the explanation is added, for example, the city gas 13A having a low calorific value (42 MJ / m ³ ) tends to have a higher ultrasonic transmission intensity than the city gas 13A having a normal calorific value (45 MJ / m ³ ). I found. Incidentally, the propagation times shown in [Table 1] and [Table 2] are the first propagation times.
Furthermore, the inventors of the present application find that the propagation time of the ultrasonic waves (the first propagation time or the second propagation time described above) changes when the gas type of the gas flowing through the gas flow path 13 is different. It has been found that the amount of change is sufficiently larger (for example, about two orders of magnitude) than the change in propagation time based on the change in gas flow rate.

  Based on these findings, the control device C of the present application derives the gas type from the propagation time of the gas flowing through the gas flow path 11, and changes the abnormality determination threshold based on the derived gas type. Configured to set.

In the case where the abnormality determination threshold value is an alarm output abnormality determination threshold value, a description will be added. The control device C determines that the first relationship (1 in the following [Table 1]) is the relationship between the first propagation time t1 and the gas type. (Relationship shown in the column and the second column), the gas flow from the first propagation time t1 measured by the propagation time measurement unit C4 and the first relationship stored in the storage unit M. And a gas type deriving unit C10 for deriving (specifying) the gas type of the gas flowing through the flow path 11.
Further, the storage unit M of the control device C has a second relationship that is a relationship between the gas type and the alarm output abnormality determination threshold (the relationship shown in the second column and the third and subsequent columns in the following (Table 1)). ) And the alarm output abnormality determination threshold corresponding to the gas type is extracted based on the gas type derived by the gas type deriving unit C10 and the second relationship, and the extracted alarm output abnormality determination threshold is extracted. An abnormality determination threshold value change setting unit C11 is provided for changing the setting.
When a description is added to the second relationship, the abnormality determination threshold value is temperature-dependent, and therefore the alarm output abnormality determination threshold value is stored in the storage unit M for each temperature range. For this reason, when the abnormality determination threshold value change setting unit C11 extracts the alarm output abnormality determination threshold value, the abnormality determination threshold value change setting unit C11 also uses the measured value of the internal temperature of the gas passage 11 measured by the temperature sensor 23 (not shown) for alarm output. An abnormality determination threshold value is extracted.

  Next, when the abnormality determination threshold is a blocking abnormality determination threshold, a description will be added. The storage unit M of the control device C has the same first relationship as when the abnormality determination threshold is an alarm output abnormality determination threshold. (Relationship between the first column and the second column in [Table 2] below) is stored. Further, the storage unit M stores a second relationship (a relationship shown in the second column and the third and subsequent columns in the following (Table 2)) that is a relationship between the gas type and the abnormality determination threshold value for blocking. Yes. The abnormality determination threshold value change setting unit C11 extracts an interruption abnormality determination threshold value corresponding to the gas type based on the gas type derived by the gas type derivation unit C10 and the second relationship, and extracts the extracted abnormality determination for interruption. Change to threshold value.

Incidentally, when the explanation is added regarding the first relationship and the second relationship, the first relationship has a relationship corresponding to a gas type having a low calorific value as the propagation time is short, and the second relationship is a gas type corresponding to a low calorific value. The higher the abnormality determination threshold (the abnormality determination threshold for alarm output and the abnormality determination threshold for interruption) are.
Therefore, the abnormality determination threshold value changing setting unit C11 changes and sets the abnormality determination threshold value to a higher abnormality determination value as the heat amount corresponding to the gas type from which the gas type is extracted is lower.

[Second Embodiment]
The ultrasonic meter 100 according to the second embodiment uses an average molecular weight as a gas composition-related value as compared with the first embodiment, that is, as a function unit, the average molecular weight is used instead of the gas type deriving unit C10. It is characterized in that it includes a deriving unit C10. Therefore, in the following, this point will be described mainly, and the description of the same configuration and control as in the first embodiment may be omitted.

In the ultrasonic meter 100 according to the second embodiment, the average molecular weight of the gas can be favorably adopted as the gas composition related value.
That is, using the first propagation time t1 and the second propagation time t2 derived from the above-described [Expression 1] and [Expression 2], the sound velocity C of the ultrasonic wave can be expressed by the following [Expression 3]. it can.
C = L / 2 · (1 / t1 + 1 / t2) (Equation 3)
For each temperature of the ultrasonic propagation medium (in this specification, gas), the sound velocity C derived by [Equation 3] and the average molecular weight of the propagation medium have a primary correlation or a secondary correlation. Have.
Therefore, in the present embodiment, the primary correlation or the secondary correlation is stored in the storage unit M as the third relationship for each temperature, and the derived sound speed C and the temperature sensor 23 measure. The average molecular weight of the propagation medium (gas) can be derived from the temperature and the third relationship.
Here, since the temperature T of the gas flowing through the gas flow path 11 can be measured by the temperature sensor 23, the average molecular weight deriving unit C10 has a first propagation time t1 measured by the propagation time measuring unit C4, The sound velocity C is obtained by introducing the second propagation time t2 and the predetermined propagation distance L into the above [Expression 3], the sound velocity C, the gas temperature T measured by the temperature sensor 23, and the third relationship. Thus, the average molecular weight of the gas is derived.
Further, the storage unit M stores a fourth relationship that is a relationship between the average molecular weight and the abnormality determination threshold, and the abnormality determination threshold change setting unit C11 includes the average molecular weight of the gas derived by the average molecular weight deriving unit C10. Based on the fourth relationship, an abnormality determination threshold value corresponding to the average molecular weight is extracted and changed to the extracted abnormality determination threshold value.
The fourth relationship is the second relationship shown in [Table 1] and [Table 2] of the first embodiment for each of the abnormality determination threshold for alarm output and the abnormality determination threshold for interruption as the abnormality determination threshold. In substantially the same way, each table is provided separately, and an abnormality determination threshold value that varies depending on the temperature is held.

[Third Embodiment]
The ultrasonic meter 100 according to the second embodiment is characterized in that a gas composition related value is acquired from an external gas type related information management server S (an example of an external server) with respect to the first embodiment. Therefore, in the following, this point will be described mainly, and the description of the same configuration and control as in the first embodiment may be omitted.
In the embodiment, the gas type related information management server S is a gas composition related value (for example, gas type) of gas flowing through the gas flow path 11 provided with the pair of transducers 10a and 10b. Are sequentially updated and stored.

The control device C is electrically connected to a gas type related information management server S provided outside via a communication network N, and the abnormality determination threshold value change setting unit C11 as the control device C performs gas type related information management. The gas type related value stored in the server S is configured to be able to be acquired sequentially.
The storage unit M is a second relationship (in the first embodiment) that is a relationship between a gas composition-related value (for example, a gas type) and an abnormality determination threshold (a concept including an abnormality determination threshold for alarm output and an abnormality determination threshold for shutoff). The same relationship as the second relationship shown) is stored.
The abnormality determination threshold value change setting unit C11 extracts the abnormality determination threshold value corresponding to the gas composition related value based on the gas composition related value and the second relationship acquired from the gas type related information management server S, and extracts the extracted abnormality determination. Change to threshold value.
[Another embodiment]

(1) In the first and third embodiments, an example in which the gas composition-related value is a gas type has been shown, but it may be a gas composition, a heat amount of gas, an average molecular weight of gas, or the like.
In this case, the memory unit M stores the relationship between the gas composition, the calorific value of the gas, the average molecular weight of the gas, and the propagation time, and the functional unit as the gas type deriving unit C10 includes the gas composition and the calorie of the gas. In addition, the configuration and control are the same as those in the first embodiment except that the functional unit derives the average molecular weight of the gas.

(2) In the above embodiment, the gas composition-related values are gas species, gas composition, heat quantity, and average molecular weight. However, the gas composition related value may be the first propagation time or the second propagation time.
That is, in the said embodiment, the memory | storage part showed the example which memorize | stores the 2nd relationship of a gas composition related value and an abnormality determination threshold value in addition to the 1st relationship of propagation time and a gas composition related value. .
However, the storage unit stores the relationship between the propagation time and the abnormality determination threshold value, and the control unit has a configuration for deriving the abnormality determination threshold value from the propagation time and the relationship between the propagation time and the abnormality determination threshold value. You may adopt.

(3) In the above embodiment, an example in which there are an abnormality determination threshold for alarm output and an abnormality determination threshold for blocking is shown as the abnormality determination threshold. It doesn't matter.

(4) In the above embodiment, the propagation time described in [Table 1] and [Table 2] is the first propagation time t1, but the difference between the first propagation time t1 and the second propagation time t2 is Since it is about several ns to several μs, it may be the second propagation time t2.
Moreover, even if it is the average value of 1st propagation time t1 and 2nd propagation time t2, the objective of this application can be implement | achieved suitably.

  The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in the other embodiment, as long as no contradiction occurs. The embodiment disclosed in this specification is an exemplification, and the embodiment of the present invention is not limited to this. The embodiment can be appropriately modified without departing from the object of the present invention.

  The ultrasonic meter of the present invention and the control method thereof are used to issue an alarm for abnormal amplification of transmission intensity of ultrasonic waves caused by fluctuations in gas composition related values (gas species, gas composition, heat quantity, average molecular weight), A versatile ultrasonic meter that can prevent abnormal shutoff of the gas flow path due to fluctuations in gas composition related values and can be used appropriately even when gas composition related values fluctuate, and its control It can be effectively used as a method.

10a: transmitter / receiver 10b: transmitter / receiver 11: gas passage 23: temperature sensor 100: ultrasonic meter C: control device L: predetermined propagation distance M: storage unit N: communication network S: gas type related information management server T: temperature V: gas flow velocity d1: first direction d2: second direction t1: first propagation time t2: second propagation time

Claims (8)

An ultrasonic wave propagates in a first direction along the flow direction and a second direction opposite to the first direction with respect to the flow direction of the gas flowing through the gas flow path, and the first direction A pair of transducers for receiving the ultrasonic wave propagated through the predetermined propagation distance and receiving the ultrasonic wave propagated through the predetermined propagation distance in the second direction,
The first propagation time in which the ultrasonic wave propagates through the predetermined propagation distance in the first direction and the second propagation time in which the ultrasonic wave propagates through the predetermined propagation distance in the second direction are measured and measured. A controller for deriving a gas flow velocity of the gas flowing through the gas passage from the propagation time and the second propagation time and the predetermined propagation distance;
The control unit adjusts the transmission intensity of the ultrasonic waves transmitted by the pair of transducers so that the reception intensity of the ultrasonic waves received by the pair of transducers becomes a target reception intensity. An ultrasonic meter that determines that the transmission / reception state of an ultrasonic wave is in an abnormal state when the transmission intensity exceeds an abnormality determination threshold,
The said control part is an ultrasonic meter which changes and sets the said abnormality determination threshold value based on the gas composition related value of the gas which flows through the said gas flow path.   The ultrasonic meter according to claim 1, wherein the control unit changes to a higher abnormality determination threshold value as the heat amount corresponding to the gas composition related value is lower. A storage unit that stores a first relationship that is a relationship between the propagation time that is the first propagation time or the second propagation time and the gas composition-related value;
The ultrasonic meter according to claim 1, wherein the control unit derives the gas composition related value of the gas flowing through the gas flow path based on the measured propagation time and the first relationship. . The storage unit stores a second relationship that is a relationship between the gas composition related value and the abnormality determination threshold value,
The said control part extracts the said abnormality determination threshold value corresponding to the said gas composition related value based on the derived | led-out said gas composition related value and said 2nd relationship, and changes and sets to the extracted said abnormality determination threshold value. 3. The ultrasonic meter according to 3. Comprising temperature measuring means for measuring the temperature of the gas flowing through the gas flow path,
The ultrasonic velocity transmitted and received by the pair of transducers, the average molecular weight as the gas composition related value of the gas flowing through the gas passage, and the gas passage A storage unit that stores a third relationship that is a relationship that the temperature of the gas has;
The control unit derives the sound speed of the ultrasonic wave from the measured propagation time which is the first propagation time or the second propagation time and the predetermined propagation distance, and the derived sound speed and the temperature measuring unit measure The ultrasonic meter according to claim 1, wherein the average molecular weight as the gas composition related value of gas is derived from the measured temperature and the third relationship. The storage unit stores a fourth relationship that is a relationship between the average molecular weight and the abnormality determination threshold,
The control unit extracts the abnormality determination threshold corresponding to the average molecular weight on the basis of the average molecular weight of the derived gas and the fourth relationship, and changes and sets the abnormality determination threshold to the extracted abnormality determination threshold. The described ultrasonic meter. The control unit is electrically connected to an external server provided outside via a communication network,
The external server is configured to sequentially update and store the gas composition related values of the gas flowing through the gas flow path in which the pair of transducers are provided,
A storage unit that stores a second relationship that is a relationship between the gas composition-related value and the abnormality determination threshold;
The controller is configured to be able to acquire the gas composition related value from the external server, and based on the acquired gas composition related value and the second relationship, the abnormality corresponding to the gas composition related value The ultrasonic meter according to claim 1, wherein a determination threshold is extracted and changed to the extracted abnormality determination threshold. An ultrasonic wave propagates in a first direction along the flow direction and a second direction opposite to the first direction with respect to the flow direction of the gas flowing through the gas flow path, and the first direction A pair of transducers for receiving the ultrasonic wave propagated through the predetermined propagation distance and receiving the ultrasonic wave propagated through the predetermined propagation distance in the second direction,
The first propagation time in which the ultrasonic wave propagates through the predetermined propagation distance in the first direction and the second propagation time in which the ultrasonic wave propagates through the predetermined propagation distance in the second direction are measured, and the measured first Deriving the gas flow velocity of the gas flowing through the gas flow path from the propagation time that is the propagation time or the second propagation time and the predetermined propagation distance,
A method of controlling an ultrasonic meter that adjusts the transmission intensity of ultrasonic waves transmitted by the pair of transducers and determines that the gas flow state is in an abnormal state when the transmission intensity exceeds an abnormality determination threshold value Because
An ultrasonic meter control method for changing and setting the abnormality determination threshold based on a gas composition related value of gas flowing through the gas flow path.

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