JP2015043002A - Ultrasonic gas meter and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic gas meter capable of suppressing an increase in man-hour due to reset of a propagation time error while protecting safety and measurement performance, and to provide a control method for the ultrasonic gas meter.SOLUTION: A μCOM 14 determines whether propagation time from transmission of an ultrasonic signal up to reception of the signal is within a predetermined time range or not, and when determining that the propagation time is not within the predetermined range, closes a gas shut-off valve 10. When the gas shut-off valve 10 is closed, theμCOM 14 opens the gas shut-off valve 10 by connecting a setter 20 and inputting a signal to the setter 20. After lapse of one hour from initial detection of a flow rate of 21 L/h or more, the μCOM 14 starts learning for a gas consumption pattern or the like indicating a gas consumption tendency. Only before start of the learning, theμCOM 14 does not close the gas shut-off valve 10 even when determining that the propagation time is not within the predetermined time range.

Description

  The present invention relates to an ultrasonic gas meter and a control method thereof.

  Currently, an ultrasonic gas meter using an ultrasonic flow velocity sensor has been proposed (for example, Patent Document 1). In the ultrasonic gas meter described above, an ultrasonic flow sensor is constituted by two acoustic transducers composed of, for example, piezoelectric transducers that operate at an ultrasonic frequency that are arranged at a predetermined distance in the gas flow path.

  Then, the ultrasonic signal generated by one transducer is received by the other transducer to measure the propagation time during which the ultrasonic signal propagates between the transducers, and the gas flow rate is intermittent based on the measured propagation time. The passage flow rate is obtained by multiplying the flow rate by the sectional area of the gas flow path and the intermittent time. Furthermore, an ultrasonic gas meter can be configured by displaying the integrated flow rate obtained by integrating the passing flow rate.

JP 2006-242658 A

  Further, the ultrasonic gas meter as described above has a function of blocking a propagation time error. This is because when a gas other than the gas to be measured has entered the flow path, when an ultrasonic flow sensor or electronic circuit has failed, or when water has entered the flow path, This is a function for judging the error and blocking the gas based on the fact that the propagation time becomes abnormal. Also, if a propagation time error occurs, the shut-off valve will not open even if the return button provided on the ultrasonic gas meter is pressed.For example, an operator may send a return permission message to the ultrasonic gas meter using a setting device. By pushing the return button, the shut-off valve opens. In this way, by preventing the user from opening the shut-off valve simply by pressing the return button, simple return is prohibited and protection is provided for safety and measurement performance.

  However, when a conventional ultrasonic gas meter is newly installed in a newly built ordinary house, a propagation time error may occur. For example, gas stoppers and pipes (flexible pipes) installed between the gas regulator and the gas appliance are subjected to an airtight inspection using helium gas at the time of shipment from the manufacturing factory. If helium gas remains in the gas stopper or the pipe, the helium gas causes a propagation time error. In particular, in a conventional ultrasonic gas meter, when a propagation time error occurs, the shut-off valve does not open by simply pressing the return button, and the propagation time error block must be canceled using a setting device or the like. For this reason, it is sufficient that the worker is near when the propagation time error occurs. However, if the worker is not near, it is necessary to go to a general house and cancel the error, which causes an increase in man-hours.

  Therefore, it may be possible to simply cancel the error by simply operating the return button for the propagation time error cancellation. In this case, however, safety and measurement performance cannot be protected. End up.

  The present invention has been made to solve such a conventional problem, and its purpose is to suppress an increase in man-hours due to the cancellation of the propagation time error while protecting the safety and measurement performance. It is an object to provide an ultrasonic gas meter and a control method thereof.

  The ultrasonic gas meter according to the present invention includes a transmission unit that intermittently transmits an ultrasonic signal in a gas flow path, a reception unit that receives the ultrasonic signal, and an ultrasonic signal transmitted from the transmission unit. Determining means for determining whether the propagation time until the ultrasonic signal is received by the receiving means is within a predetermined time range; and when determining that the propagation time is not within the predetermined time range by the determining means A shut-off means that closes the shut-off valve to stop the gas flow in the gas flow path, a gas consumption pattern that shows a tendency of gas consumption after a lapse of a specified time after first detecting a flow rate of a predetermined value or more, and a flow rate Learning means for starting learning for at least one of the usage times for each section, wherein the blocking means is not within a predetermined time range before the learning means starts learning. Even if it is determined, the shut-off valve is not closed, and after the learning is started by the learning means, the shut-off valve is closed when it is determined that the propagation time is not within a predetermined time range. When it is determined that the propagation time is not within the predetermined time range after learning starts and the shut-off valve is closed, a shut-off valve is opened by inputting a return permission message from a specified device and pressing the return button. It is characterized by making it.

  According to the ultrasonic gas meter of the present invention, the shut-off valve is not closed even when it is determined that the propagation time is not within the predetermined time range before the start of learning. For this reason, when there is a possibility that helium gas before the start of learning remains without being purged, the shutoff valve is not closed. Therefore, there is no need to cancel the propagation time error, and man-hours are not increased. Further, when it is determined that the propagation time is not within the predetermined time range after the start of learning, the shut-off valve is closed. Here, the possibility that helium gas remains without being purged after the start of learning is extremely low. Therefore, after the start of learning, the propagation valve becomes abnormal and the shut-off valve is closed when an ultrasonic flow rate sensor, an electronic circuit, or the like fails or when water enters the flow path. . In order to open the valve, a signal input from a prescribed device is required, and safety and measurement performance can be protected. Therefore, it is possible to suppress an increase in man-hours due to the cancellation of the propagation time error while protecting the safety and measurement performance.

  In the ultrasonic gas meter of the present invention, the predetermined time range is preferably 160 μs or more and 330 μs or less.

According to this ultrasonic gas meter, the predetermined time range is not less than 160 μs and not more than 330 μs. Here, when an ultrasonic signal is transmitted and received against the flow of LP gas having a flow rate of 10 m ³ , the propagation time does not exceed 330 μs. On the other hand, when an ultrasonic signal is transmitted / received along an air flow having a flow rate of 10 m ³ , the propagation time does not fall below 160 μs. For this reason, when the flow path is filled with LP gas or air, the propagation time falls within the range of 160 μs to 330 μs. Therefore, in the ultrasonic gas meter for LP gas, when helium gas enters, when the ultrasonic flow rate sensor or electronic circuit breaks down, or when water enters the flow path, the propagation time is Based on the abnormality, it is possible to determine an error and appropriately determine a propagation time error.

  The ultrasonic gas meter control method of the present invention includes a transmission step of intermittently transmitting an ultrasonic signal in a gas flow path, a reception step of receiving the ultrasonic signal, and an ultrasonic signal in the transmission step. Is transmitted, and a determination step of determining whether the propagation time from the reception of the ultrasonic signal in the reception step is within a predetermined time range, and the propagation time is not within the predetermined time range in the determination step When judged, a shut-off process for closing the gas flow in the gas flow path by closing the shut-off valve, and a gas consumption indicating a tendency of gas consumption after a predetermined time has elapsed since the flow rate exceeding a predetermined value is detected for the first time. A learning step that starts learning for at least one of a pattern and a usage time for each flow rate section, and in the blocking step, the propagation is performed before the learning starts in the learning step. Even if it is determined that the interval is not within the predetermined time range, the shut-off valve is not closed, and when it is determined that the propagation time is not within the predetermined time range after the start of learning in the learning step, When the shut-off valve is closed when it is determined that the propagation time is not within the predetermined time range after learning is started in the learning step, a return permission message is input from a specified device and the return button is pressed. In this way, the shut-off valve is opened.

  Further, according to the method for controlling an ultrasonic gas meter of the present invention, the shut-off valve is not closed even when it is determined that the propagation time is not within the predetermined time range before the start of learning. For this reason, when there is a possibility that helium gas before the start of learning remains without being purged, the shutoff valve is not closed. Therefore, there is no need to cancel the propagation time error, and man-hours are not increased. Further, when it is determined that the propagation time is not within the predetermined time range after the start of learning, the shut-off valve is closed. Here, the possibility that helium gas remains without being purged after the start of learning is extremely low. Therefore, after the start of learning, the propagation valve becomes abnormal and the shut-off valve is closed when an ultrasonic flow rate sensor, an electronic circuit, or the like fails or when water enters the flow path. . In order to open the valve, a signal input from a prescribed device is required, and safety and measurement performance can be protected. Therefore, it is possible to suppress an increase in man-hours due to the cancellation of the propagation time error while protecting the safety and measurement performance.

  In addition, with the above-mentioned equipment, a gas operator holds and operates a setting device (handy terminal) that can send and receive a return permission message to the gas meter and a return permission message via a telephone line via a network control device. This means the central equipment of a centralized monitoring system that can be used. When the gas meter receives this return permission message, the gas meter waits for a return signal input from the return button, and then returns (opens) the shut-off valve when the return button is pressed.

  According to the ultrasonic gas meter of the present invention, it is possible to suppress an increase in man-hours due to cancellation of a propagation time error while protecting safety and measurement performance.

It is a lineblock diagram showing the ultrasonic gas meter concerning the embodiment of the present invention. FIG. 2 is a configuration diagram showing the inside of μCOM shown in FIG. 1. It is a flowchart which shows the control method of the ultrasonic type gas meter which concerns on this embodiment, Comprising: The process regarding the valve closing of a gas cutoff valve is shown. It is a flowchart which shows the control method of the ultrasonic gas meter which concerns on this embodiment, Comprising: The process regarding valve opening of a gas cutoff valve is shown. It is a flowchart which shows the control method of the ultrasonic gas meter which concerns on a reference example, Comprising: The process regarding the valve closing of a gas cutoff valve is shown. It is a flowchart which shows the control method of the ultrasonic gas meter which concerns on a reference example, Comprising: The process regarding valve opening of a gas cutoff valve is shown.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating an ultrasonic gas meter according to an embodiment of the present invention. The ultrasonic gas meter 1 shown in FIG. 1 includes two acoustic transducers (disposed by a distance L in the gas flow path and opposed to each other so as to form an angle θ with respect to the gas flow direction Y). (Transmission means, reception means) TD1, TD2.

  The two acoustic transducers TD1, TD2 are composed of, for example, piezoelectric vibrators that operate at an ultrasonic frequency. The gas flow path is provided with a gas shut-off valve (shut-off valve) 10 that shuts off the gas flow path by closing the valve upstream of both acoustic transducers TD1 and TD2.

  Each transducer TD1, TD2 is connected to a transmitter circuit 12 and a receiver circuit 13 via transducer interface (I / F) circuits 11a, 11b, respectively. The transmission circuit 12 transmits, in the form of a pulse burst, a signal for driving one of the transducers TD1 and TD2 to generate an ultrasonic signal under the control of the microcomputer (μCOM) 14.

  The receiving circuit 13 includes an amplifier 13a that receives signals from the other transducers TD1 and TD2 that have received the ultrasonic signal that has passed through the gas flow path and amplifies the ultrasonic signal to a predetermined intensity. The amplification degree of the amplifier 13a can be adjusted by the μCOM 14. Further, a display 15 and a return button 16 are connected to the μCOM 14.

  FIG. 2 is a block diagram showing the inside of the μCOM 14 shown in FIG. As shown in FIG. 2, the μCOM 14 includes a central processing unit (CPU) 14a that performs various processes according to a program, a ROM 14b that is a read-only memory that stores programs for processes performed by the CPU 14a, and various types of CPU 14a. A RAM 14c, which is a readable / writable memory having a work area used in the processing process, a data storage area for storing various data, and the like are incorporated. These are connected to each other by a bus line 14d.

  The CPU 14a has a propagation time error determination function (determination unit), a propagation time error blocking function (blocking unit), a propagation time error cancellation function, and a learning function (learning unit).

  The propagation time error determination function determines whether the propagation time from when an ultrasonic signal is transmitted by one of the transducers TD1 and TD2 to when the ultrasonic signal is received by the other transducer TD1 and TD2 is within a predetermined time range. It is a function to judge. Here, the predetermined time range is 160 μs or more and 330 μs or less in the present embodiment. In general, when the gas to be measured is filled in the gas flow path, the propagation time is within the range of 160 μs to 330 μs.

  On the other hand, when a gas other than the gas to be measured has entered the flow path, when an ultrasonic flow sensor or electronic circuit has failed, or when water has entered the flow path, The propagation time will be less than 160 μs or more than 330 μs. For this reason, CPU14a can judge whether it is in an abnormal state by judging whether propagation time is in a predetermined time range.

The reason why the predetermined time range is as described above is as follows. That is, when ultrasonic waves are transmitted and received against the flow of LP gas having a flow rate of 10 m ³ , the propagation time does not exceed 330 μs. On the other hand, when ultrasonic waves are transmitted and received along an air flow having a flow rate of 10 m ³ , the propagation time does not fall below 160 μs.

  The propagation time error cutoff function is a function that stops the gas flow in the gas flow path by closing the gas cutoff valve 10 when the propagation time error determination function determines that the propagation time is not within a predetermined time range. If the gas is used in the abnormal state as described above, it is impossible to protect the safety aspect and the measurement aspect. For this reason, the propagation time error cutoff function closes the gas cutoff valve 10 in order to protect the safety and measurement aspects.

  The propagation time error canceling function is such that when the gas cutoff valve 10 is closed by the propagation time error cutoff function, the setter 20 is connected, a return permission message is input, and the return button 16 is pressed to shut off the gas. This is a function for opening the valve 10. In order to reliably prohibit the use of gas in the above abnormal state, it is desirable that the gas cutoff valve 10 does not open only by the operation of the return button 16 by the consumer. This is because the gas may be reused by the user's operation before the abnormal state is recovered. For this reason, the propagation time error canceling function opens the gas shut-off valve 10 through, for example, an input of a return permission message from the setting device 20 possessed by the worker.

  The learning function is a function for learning the usage state of the gas. This learning function is executed after 1 hour (specified time) has elapsed since the ultrasonic gas meter 1 was installed and the flow rate of 21 L / h (predetermined value) or more was detected for the first time. The contents learned here are a gas consumption pattern indicating a tendency of gas consumption and a gas usage time for each flow rate category.

  This learning function monitors the gas flow rate for 14 days at the time of learning, divides the 14 days into the first 3 days and the latter 11 days, and uses the flow cutoff value for closing the gas cutoff valve 10 as the gas consumption pattern. Set accordingly. The flow rate cutoff value includes a total flow rate cutoff value and an increased flow rate cutoff value. In addition, the learning function monitors the gas use time for each flow rate section, and sets the continuous use shut-off time for causing the gas shut-off valve 10 to be closed for each flow rate section.

  Further, in the present embodiment, the propagation time error cutoff function does not close the gas cutoff valve 10 even when the propagation time is determined not to be within the predetermined time range before learning by the learning function. . Before the start of learning, there is a possibility that helium gas remains in the gas plug or pipe (flexible pipe) between the gas regulator and the gas appliance and is not purged. For this reason, if the gas shut-off valve 10 is closed, for example, an operator goes to the installation location of the ultrasonic gas meter 1 and opens the gas shut-off valve 10 using the setting device 20. However, in this embodiment, the shutoff valve is not closed when there is a possibility that the helium gas before the start of learning remains without being purged. As a result, it is not necessary to perform release using the setting device 20 or the like, so that man-hours are not increased.

  The propagation time error cutoff function closes the gas cutoff valve 10 when it is determined that the propagation time is not within the predetermined time range after the learning function starts learning. Here, the possibility that helium gas remains without being purged after the start of learning is extremely low. Therefore, after the start of learning, the propagation valve becomes abnormal and the shut-off valve is closed when an ultrasonic flow rate sensor, an electronic circuit, or the like fails or when water enters the flow path. . As a result, safety and measurement performance can be protected.

  Next, a detailed operation of the ultrasonic gas meter 1 according to the present embodiment will be described with reference to a flowchart. FIG. 3 is a flowchart showing a control method of the ultrasonic gas meter 1 according to the present embodiment, and shows processing related to closing of the gas cutoff valve 10.

  As shown in FIG. 3, the CPU 14a controls the transmission circuit 12 to operate the transducer I / F circuits 11a and 11b, thereby transmitting an ultrasonic signal from one of the acoustic transducers TD1 and TD2 (S1). . Next, the other acoustic transducers TD1, TD2 receive the ultrasonic signals (S2), and the CPU 14a amplifies the ultrasonic signals received by the other acoustic transducers TD1, TD2 to a predetermined intensity by the amplifier 13a, and the propagation time. Is calculated (S3). The calculation of the propagation time is performed individually for each of the transmission of the ultrasonic signal from the upstream side and the transmission of the ultrasonic signal from the downstream side with respect to the gas flow.

  Thereafter, the CPU 14a determines whether or not the propagation time calculated in step S3 is within a predetermined time range (S4). When it is determined that it is not within the predetermined time range (S4: NO), the CPU 14a increments the counter value (S5), and determines whether or not the counter value is equal to or greater than a specified value (S6). Here, the specified value is initially “15”, for example, and is preferably a variable number.

  If it is determined that the counter value is not equal to or greater than the specified value (S6: NO), the process proceeds to step S1. On the other hand, when it is determined that the counter value is equal to or greater than the specified value (S6: YES), the CPU 14a determines whether it is before learning (S7). When it is determined that it is not before learning (S7: NO), there is little possibility that helium gas remains in the gas stopper or the pipe (flexible pipe), and it can be determined that this is a true abnormal state. For this reason, the CPU 14a closes the gas shutoff valve 10 in order to protect safety and measurement performance (S8). Thereafter, the process shown in FIG. 3 ends.

  On the other hand, if it is determined that it is before learning (S7: YES), helium gas may remain in the gas plug or pipe (flexible pipe), so there is a possibility that it is not a true abnormal state. Therefore, the CPU 14a resets the counter value without closing the gas shut-off valve 10 so that it is not necessary to perform release using the setting device 20 or the like (S9). Thereafter, the process shown in FIG. 3 ends.

  By the way, when it is determined that the propagation time is within the predetermined time range (S4: YES), the propagation time is normal, so the CPU 14a resets the counter value (S9), and then the process shown in FIG. finish.

  FIG. 4 is a flowchart showing a control method of the ultrasonic gas meter 1 according to the present embodiment, and shows processing related to opening of the gas cutoff valve 10. As shown in FIG. 4, first, the CPU 14a determines whether or not a return permission message has been input from the setting device 20 (S11).

  When it is determined that the return permission message has not been input from the setting device 20 (S11: NO), this process is repeated until it is determined that the message has been input. On the other hand, when it is determined that the return permission message has been input from the setting device 20 (S11: YES), the CPU 14a determines whether the return button 16 has been pressed (S12). If it is determined that the return button 16 has not been pressed (S12: NO), this process is repeated until it is determined that the return button 16 has been pressed. On the other hand, if it is determined that the return button 16 has been pressed (S12: YES), the CPU 14a opens the gas cutoff valve 10 (S13). Thereafter, the process shown in FIG. 4 ends.

  In this way, according to the ultrasonic gas meter 1 and the control method thereof according to the present embodiment, the gas cutoff valve 10 is set even when it is determined that the propagation time is not within the predetermined time range before the start of learning. Do not close. For this reason, the gas shut-off valve 10 is not closed when there is a possibility that the helium gas before the start of learning remains without being purged. Therefore, there is no need to cancel the propagation time error, and man-hours are not increased. Further, when it is determined that the propagation time is not within the predetermined time range after the start of learning, the gas cutoff valve 10 is closed. Here, the possibility that helium gas remains without being purged after the start of learning is extremely low. Therefore, after the start of learning, the propagation time becomes abnormal and the gas shut-off valve 10 is closed when an ultrasonic flow sensor or an electronic circuit breaks down or when water enters the flow path. It becomes. In order to open the valve, a signal input from a prescribed device is required, and safety and measurement performance can be protected. Therefore, it is possible to suppress an increase in man-hours due to the cancellation of the propagation time error while protecting the safety and measurement performance.

The predetermined time range is 160 μs or more and 330 μs or less. Here, when an ultrasonic signal is transmitted and received against the flow of LP gas having a flow rate of 10 m ³ , the propagation time does not exceed 330 μs. On the other hand, when an ultrasonic signal is transmitted / received along an air flow having a flow rate of 10 m ³ , the propagation time does not fall below 160 μs. For this reason, when the flow path is filled with LP gas or air, the propagation time falls within the range of 160 μs to 330 μs. Therefore, in the ultrasonic gas meter for LP gas, when helium gas enters, when the ultrasonic flow rate sensor or electronic circuit breaks down, or when water enters the flow path, the propagation time is Based on the abnormality, it is possible to determine an error and appropriately determine a propagation time error.

  Next, a reference example will be described. The ultrasonic gas meter 1 and its control method according to the reference example are the same as those of the present embodiment, but the processing contents are different from those of the present embodiment. Hereinafter, differences will be described.

  When the propagation time is not within a predetermined time range before learning, the ultrasonic gas meter 1 according to the reference example does not prohibit the closing operation of the gas cutoff valve 10 but presses the return button 16 without using the setting device 20. Only the gas shut-off valve 10 is opened.

  Next, the detailed operation of the ultrasonic gas meter 1 according to the reference example will be described with reference to a flowchart. FIG. 5 is a flowchart showing a control method of the ultrasonic gas meter 1 according to the reference example, and shows processing related to closing of the gas cutoff valve 10. Note that steps S31 to S36 and step S40 shown in FIG. 5 are the same processes as steps S1 to S6 and step S10 shown in FIG.

  As shown in FIG. 5, when it is determined that the counter value is equal to or greater than the specified value (S26: YES), the CPU 14a determines whether it is before learning (S27). When it is determined that it is not before learning (S27: NO), there is little possibility that helium gas remains in the gas plug or the pipe, and it can be determined that the state is a true abnormal state. Therefore, the CPU 14a closes the gas shut-off valve 10 in order to protect safety and measurement performance (S28). At this time, the CPU 14a closes the gas shut-off valve 10 as a first valve closed state that can be opened by a return permission message from the setting device 20. Thereafter, the process shown in FIG. 5 ends.

  On the other hand, when it is determined that it is before learning (S27: YES), helium gas may remain in the gas stopper or the pipe, and therefore there is a possibility that it is not a true abnormal state. Therefore, the CPU 14a closes the gas cutoff valve 10 as a second valve closed state that can be opened only by operating the return button 16 without using the setting device 20 (S29). Thereafter, the process shown in FIG. 5 ends.

  FIG. 6 is a flowchart showing a control method of the ultrasonic gas meter 1 according to the reference example, and shows a process related to opening of the gas cutoff valve 10. As shown in FIG. 6, first, the CPU 14a determines whether or not the first valve is closed (S31). When it is determined that the first valve is closed (S31: YES), the CPU 14a determines whether a return permission message has been input from the setting device 20 (S32).

  When it is determined that the return permission message has not been input from the setting device 20 (S32: NO), this process is repeated until it is determined that it has been input. On the other hand, when it is determined that the return permission message has been input from the setting device 20 (S32: YES), the CPU 14a determines whether the return button 16 has been pressed (S33). When it is determined that the return button 16 has not been pressed (S33: NO), this process is repeated until it is determined that the return button 16 has been pressed. On the other hand, if it is determined that the return button 16 has been pressed (S33: YES), the CPU 14a opens the gas cutoff valve 10 (S34). Thereafter, the process shown in FIG. 6 ends.

  Thus, in the first valve closed state, simply pressing the return button 16 does not open the gas shut-off valve 10, and the process of step S32 functions as a return prohibiting means.

  On the other hand, when it is determined that the first valve is not closed (S31: NO), since it can be determined that the second valve is closed, the CPU 14a determines whether or not the return button 16 has been pressed (S33). When it is determined that the return button 16 has not been pressed (S33: NO), this process is repeated until it is determined that the return button 16 has been pressed. On the other hand, if it is determined that the return button 16 has been pressed (S33: YES), the CPU 14a opens the gas cutoff valve 10 (S34). Thereafter, the process shown in FIG. 6 ends.

  As described above, in the second valve closed state, the gas shut-off valve 10 is opened by pressing the return button 16, and the processes in steps S33 and S34 function as a return means.

  In this way, according to the ultrasonic gas meter 1 and its control method according to the reference example, when the propagation time is determined not to be within the predetermined time range after the start of learning and the gas shut-off valve 10 is closed, The gas shutoff valve 10 is not opened only by pressing the return button. Here, the possibility that helium gas remains without being purged after the start of learning is extremely low. Therefore, after the start of learning, the propagation time becomes abnormal and the gas shut-off valve 10 is closed when an ultrasonic flow sensor or an electronic circuit breaks down or when water enters the flow path. It becomes. And in order to open a valve, the signal input from the setting device 20 is required, and it can aim at protection about safety | security and measurement performance. Further, when it is determined that the propagation time is not within the predetermined time range before the start of learning and the gas shut-off valve 10 is closed, the shut-off valve is opened by pressing the return button 16. For this reason, when the gas cutoff valve 10 is closed when there is a possibility that helium gas before the start of learning remains without being purged, no signal input from the setting device 20 is required to open the valve. The valve can be opened by pressing the return button 16. Therefore, it does not lead to an increase in man-hours due to cancellation of the propagation time error. Therefore, it is possible to suppress an increase in man-hours due to the cancellation of the propagation time error while protecting the safety and measurement performance.

  Similarly to this embodiment, the propagation time becomes abnormal when helium gas enters, when an ultrasonic flow rate sensor, an electronic circuit, or the like fails, or when water enters the flow path. Based on this, it is possible to determine the error and appropriately determine the propagation time error.

  As described above, the present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment, and may be modified without departing from the gist of the present invention. For example, in the above embodiment, each value is not limited to the above value, and can be changed as appropriate.

  Furthermore, in this embodiment, it aims at suppressing the man-hour increase by helium gas remaining, but it is not restricted to helium gas, You may suppress the man-hour increase by other gas.

  In the present embodiment, when the propagation time is not within the predetermined time range before learning, the closing operation of the gas shut-off valve 10 is prohibited. Further, in the reference example, when the propagation time is not within a predetermined time range before learning, the operation of the return button 16 or the like is performed without using the setting device 20 or the like instead of prohibiting the closing operation of the gas cutoff valve 10. Therefore, the gas cutoff valve 10 is opened. Such first and reference examples share common technical features in that the processing contents are different before and after learning.

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic gas meter 10 ... Gas cutoff valve 11a, 11b ... Transducer I / F circuit 12 ... Transmission circuit 13 ... Reception circuit 13a ... Amplifier 14 ... μCOM
14a ... CPU (determination means, shut-off means, learning means, return means, return prohibition means)
14b ... ROM
14c ... RAM
14d ... bus line 15 ... display 16 ... return button 20 ... setter TD1, TD2 ... acoustic transducer (transmitting means, receiving means)

Claims (2)

Transmission means for intermittently transmitting ultrasonic signals in the gas flow path;
Receiving means for receiving the ultrasonic signal;
A determination unit that determines whether a propagation time from when the ultrasonic signal is transmitted by the transmission unit to when the ultrasonic signal is received by the reception unit is within a predetermined time range;
A shut-off means that shuts off the gas flow in the gas flow path by closing the shut-off valve when the judgment means determines that the propagation time is not within a predetermined time range;
A gas consumption pattern indicating a tendency of gas consumption after a predetermined time has elapsed since the first detection of a flow rate of a predetermined value or more, and a learning means for starting learning about at least one of the usage times for each flow rate category,
The shut-off means does not close the shut-off valve even if it is determined that the propagation time is not within a predetermined time range before learning by the learning means, and the propagation after the learning by the learning means starts. When it is determined that the time is not within the predetermined time range, the shut-off valve is closed.
When it is determined that the propagation time is not within the predetermined time range after learning by the learning means and the shut-off valve is closed, a shut-off is performed by inputting a return permission message from a prescribed device and pressing the return button. An ultrasonic gas meter characterized by opening a valve. A transmission step of intermittently transmitting an ultrasonic signal in the gas flow path;
Receiving the ultrasonic signal; and
A determination step of determining whether the propagation time from the transmission of the ultrasonic signal in the transmission step to the reception of the ultrasonic signal in the reception step is within a predetermined time range;
A shut-off step of closing the shutoff valve to stop the gas flow in the gas flow path when the propagation time is determined not to be within a predetermined time range in the judging step;
A gas consumption pattern indicating a tendency of gas consumption after the lapse of a specified time after first detecting a flow rate equal to or greater than a predetermined value, and a learning step of starting learning for at least one of the usage times for each flow rate category,
In the shut-off step, the shut-off valve is not closed even if it is determined that the propagation time is not within a predetermined time range before the learning start in the learning step, and the propagation after the learning start in the learning step When it is determined that the time is not within the predetermined time range, the shut-off valve is closed.
When it is determined that the propagation time is not within a predetermined time range after the start of learning in the learning step and the shut-off valve is closed, a shut-off is performed by inputting a return permission message from a prescribed device and pressing the return button. A method for controlling an ultrasonic gas meter, characterized by opening a valve.

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