JP2012177707A - Gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas meter which avoids early closure of a use time even when using gas equipment employing proportional control.SOLUTION: Average flow rates Qave1, Qave2, and so on are measured at intervals of 15 seconds. When |Qave3-Qave4|/Qave3>3% is true at a timing T1, (Qave3-Qave1)=(flow rate 1) is registered at a timing T2, and a corresponding continuous use time is set. When |Qave3-Qave4|/Qave3<3% is true at a timing T3 according as a gas flow rate is gradually reduced due to proportional control, (maximum registered flow rate (flow rate 1))-(sum of registered flow rates ((flow rate 1)+(flow rate 2))-(current average flow rate Qave4))=(flow rate 1') is defined if |sum of registered flow rates ((flow rate 1)+(flow rate 2))-(current average flow rate Qave4)|>(a constant flow rate) is satisfied and (sum of registered flow rates ((flow rate 1)+(flow rate 2))>(current average flow rate Qave4) is true, and the flow rate 1' is set as a new registered flow rate at a timing T4, and a corresponding continuous use time is set.

Description

  The present invention sets the continuous use time according to the average flow rate when the absolute value of the amount of change in the average flow rate of the gas exceeds the criterion, and the gas use time from the time of setting the continuous use time The present invention relates to a gas meter having a usage time cutoff function that shuts off a gas by closing a cutoff valve when a continuous usage time is reached.

  Conventionally, as shown in, for example, Japanese Patent Application Laid-Open No. 2003-302274 (Patent Document 1), a gas meter is used in order to cope with forgetting to turn off a gas device or incomplete sealing of a gas stopper. It has a function to shut off the operating time to shut off the gas when it is abnormally long. The continuous use time is set as a criterion for use time until the gas is shut off, and the continuous use time is determined according to the average gas flow rate. In this usage time cutoff function, for example, the average flow rate of gas is detected at a predetermined timing of 15 seconds, and if there is a change in the average flow rate, the continuous usage time is set according to the average flow rate. .

  FIG. 7 is a diagram for explaining an example of the operation of a conventional gas meter usage time cutoff function. In the case of FIG. 7, the change in the flow rate is determined by detecting the average gas flow rate at a timing of 15 seconds. . When one gas appliance is used and the gas flow rate is the average flow rate Qave1, another gas appliance is used and the flow rate becomes the average flow rate Qave2, Qave3. For example, the knob of the gas stove is turned to become the average flow rate Qave4, Qave5. This is the case. In this case, it is detected that the average flow rate has changed from Qave1 to Qave2 at the timing of T1, and the change determination is performed at T1.

  Then, if | Qave1-Qave2 | / Qave1> 3% by the change determination, it is registered as Qave3-Qave1 = flow rate 1 at the timing of T2. Then, from this timing T2, the continuous use time corresponding to the registered flow rate 1 is set, and the timer is started (reset). Further, if it is detected that the average flow rate has changed from Qave3 to Qave4 at the timing of T3, and if | Qave3-Qave4 | / Qave3> 3% by this T3 change determination, then at the timing of T4, Qave3-Qave5 = Since the flow rate 2 is a decrease amount, the flow rate 1−the flow rate 2 = the flow rate 1 ′ is re-registered as a new flow rate. Then, the continuous use time corresponding to the flow rate 1 'is set, and the timer is started (reset).

JP 2003-302274 A

  However, the logic of the conventional usage time cutoff function has the following problems. For example, when a bathroom heater / dryer is used, there is a problem that the usage time is cut off earlier than the timer of the bathroom heater / dryer set by the user. When this cause was investigated, it turned out that it is a malfunction peculiar to the gas appliance which is performing proportional control.

  A bathroom heater / dryer is a gas appliance that boils hot water, generates hot air using it, and warms the bathroom and dressing room. Initially, a large flow of gas is used until the water is warmed up at once, but the amount of gas used is gradually reduced (proportional control) and the amount of combustion is reduced as the temperature of the hot water rises. It has become. The apparatus for performing the proportional control includes a temperature detection unit, an electronic control unit, and an electromagnetic proportional valve. The electronic control unit detects the temperature of water heated by the burner with the temperature detection unit. A current corresponding to the temperature difference between the temperature and the set temperature is supplied to the electromagnetic proportional valve. Thereby, the flow rate of the gas flowing through the electromagnetic proportional valve becomes inversely proportional to the temperature difference. Recently, proportional control is performed not only in a bathroom heater / dryer but also in a gas stove, a gas rice cooker, a gas small water heater, a gas fan heater, and the like.

  In this way, with the recently increasing proportionally controlled gas appliances, the phenomenon that the amount of gas used increases and decreases slowly and slowly, and the conventional usage time cutoff function logic accurately prevents the usage time cutoff. There are also cases where it is impossible. In particular, equipment such as bathroom dryers may be used continuously for 3 to 4 hours, and as the room temperature gradually rises, the amount of gas combustion gradually decreases and the usage time is shut off quickly. It is easy to generate a problem that occurs.

  For example, FIG. 6 shows an operation example of a conventional logic when a proportionally controlled gas appliance is used. The change determination is performed at the timing of T1, and is registered as Qave3-Qave1 = flow rate 1 at the timing of T2, and it is the same as FIG. 7 until the continuous use time corresponding to the flow rate 1 is set from this timing T2. Thereafter, the flow rate of the gas gradually decreases by proportional control, and at the timing of T3, | Qave3-Qave4 | / Qave3 <3%, and no change in the flow rate is detected. Therefore, a new flow rate is not set at the timing of T4. Thereafter, the timer of the continuous use time corresponding to the flow rate 1 is continued as it is.

  Thus, since it is not caught that the usage-amount of gas is decreasing little by little, gas interruption | blocking will be performed by continuous use time with the large flow volume registered initially. For example, when the operation of a bathroom heater / dryer is started in winter, when the water temperature and temperature are both low, the water is heated to hot water at a stretch. At that time, for example, if the gas is used at 600 L / h, a timer for 85 minutes starts. After that, if the temperature of water gradually rises, the amount of gas combustion (usage) should decrease, and accordingly the long use time (eg 720 minutes) timer should be restarted to extend the continuous use time However, such processing cannot be performed. For this reason, it is assumed that 600 L / h has been used all the time, and the usage time is cut off after 85 minutes have passed.

  The present invention solves the problem that even if a gas instrument that performs proportional control is used in a gas meter, the usage time is cut off earlier than the actual amount of gas used, and the cutoff is performed at an appropriate usage time. Let it be an issue.

  The gas meter according to claim 1 detects the average flow rate of gas at a predetermined timing, and when the absolute value of the change amount of the average flow rate exceeds a criterion, a new flow rate corresponding to the detected average flow rate is registered. Is set as the continuous use time according to the average flow rate, and when the gas use time from the setting of the continuous use time reaches the continuous use time, the shutoff valve is closed to shut off the gas. When the absolute value of the detected change amount of the average flow rate does not exceed the determination criterion, a continuous use time setting determination process is performed and the setting determination process is performed a predetermined number of times. Each time it is repeated, a new flow rate corresponding to the detected average flow rate is registered, and a continuous use time corresponding to the detected average flow rate is set.

  According to the gas meter of claim 1, when the absolute value of the detected change amount of the average flow rate does not exceed the determination criterion, the setting determination process for the continuous use time is performed. It is possible to set the time, and even when using a gas device performing proportional control, it is possible to shut off at an appropriate usage time without shutting down the usage time earlier than the actual gas usage. Further, since the setting of the continuous use time is set every predetermined number of times, continuous update of the continuous use time due to each setting can be avoided, and appropriate control can be performed based on the registered new flow rate.

It is a principal part block diagram of the gas meter which concerns on embodiment of this invention. It is a flowchart in an embodiment. It is a figure which shows an example of operation | movement of embodiment. It is a flowchart in other embodiment. It is a flowchart in other embodiments. It is a figure which shows the problem in the conventional logic. It is a figure which shows an example of the operation | movement of the conventional logic.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a principal block diagram of a gas meter according to an embodiment of the present invention. The gas meter 100 includes a microcomputer (hereinafter referred to as a microcomputer) 10, a flow rate detection unit 20, a blocking unit 30, and an alarm warning signal output unit 40. The microcomputer 10 includes a CPU 10a that performs various processes according to a processing program, a ROM 10b that stores a program for processes performed by the CPU 10a, a work area (a data storage area that stores various data, etc.) that is used in various processes in the CPU 10a. ), A timer 10d for measuring the gas usage time, and the like, and these elements are connected by a bus line.

  The flow rate detection unit 20 includes a flow rate sensor such as an ultrasonic sensor that can detect an instantaneous flow rate of gas flowing through a gas flow path (not shown). The ultrasonic sensor detects the instantaneous flow rate from the signal propagation time of the ultrasonic signal propagating in the gas flow path. The microcomputer 10 samples the instantaneous flow rate detected by the flow rate detection unit 20, and measures the average flow rate every 15 seconds, which is a predetermined timing. The shut-off unit 30 includes a drive circuit that drives a shut-off valve installed in the gas supply path. Further, the cutoff notice signal output unit 40 outputs a cutoff notice signal to the gas leak alarm device 200 connected to the gas meter 100, and is a predetermined time before the set continuous use time (for example, 7 minutes). A shut-off notice signal is output before).

  The CPU 10a of the microcomputer 10 measures the average flow rate every 15 seconds by the timer interrupt signal from the timer 10d, and determines the change in flow rate based on the previous average flow rate and the current average flow rate. Then, as described later, the continuous use time is set when the absolute value of the change amount of the average flow rate exceeds the determination criterion. Further, when the gas use time from the setting of the continuous use time reaches the continuous use time, a shut-off signal is output to the shut-off unit 30, and the shut-off valve is closed to shut off the gas.

  In addition, when the detected absolute value of the change amount of the average flow rate does not exceed the determination criterion, the CPU 10a performs a continuous use time setting determination process. In this setting determination process, as described later, the continuous use time is reset based on the average flow rate and the total of the registered flow rates. In the second embodiment, when the gas use time from the setting of the continuous use time reaches a predetermined time before the continuous use time (for example, 7 minutes), the duration is reset as described above and shut off. Outputs a warning signal.

FIG. 2 is a main part flowchart in the embodiment. This flowchart shows an interrupt process by a timer interrupt executed in parallel with the main process in the CPU 10a of the gas meter 100, and the operation will be described with reference to FIG. In the main process, various other processes are performed. The process in FIG. 2 is started every 15 seconds, the average flow rate is measured in step S1, and the change is determined in step S2. In this change determination, the determination standard is set to 3% based on the previous average flow rate Qave (i-1) and the current average flow rate Qave (i).
| Qave (i-1) -Qave (i) | / Qave (i-1)> 3%
It is determined whether or not the above condition is satisfied.

If the condition is satisfied in step S2 (if there is a change), in step S3,
Qave (i) −Qave (i−2) = registered flow rate Q
Calculate and remember as Then, the process proceeds to step S5.

  If the condition is not satisfied in step S2, a setting determination process is performed in step S4, and the process proceeds to step S5. In this setting determination process, the condition that the absolute value of the difference between (1) (the sum of registered flow rates QS registered so far (previous average flow rate)) and (current average flow rate Qi) is greater than or equal to the second determination criterion. Is satisfied. The second determination criterion is a constant flow rate (for example, 21 L / h) or a constant ratio (for example, 0.5%) with respect to the sum of the registered flow rates. If the condition (1) is satisfied and (the sum of the registered flow rates) is larger than (the current average flow rate), a new registered flow rate is calculated.

  This new registered flow rate is calculated as follows. The maximum registered flow rate QMX up to the present time, and a value obtained by subtracting (sum of registered flow rates QS) − (current average flow rate Qi) from the maximum registered flow rate QMX is set as a new registered flow rate. Then, this registered flow rate is stored.

  In step S5, it is determined whether or not the registered flow rate has been previously calculated. If not, the process returns to the original routine, and if there is, the process proceeds to step S6. In step S6, the previously calculated (stored) registered flow rate is registered. In step S7, a continuous use time corresponding to the registered flow rate is set. In step S8, the timer is restarted to return to the original routine. .

  FIG. 3 is a diagram illustrating an example of the operation of the above-described embodiment, and the change in the flow rate is determined by detecting the average flow rate of the gas at a timing of 15 seconds as in the conventional example of FIG. It is. Change determination is performed at the timing of T1, and is registered as Qave3-Qave1 = flow rate 1 at the timing of T2, and the continuous use time corresponding to the flow rate 1 is set from this timing T2. Thereafter, the flow rate of the gas gradually decreases by proportional control, and at the timing of T3, | Qave3-Qave4 | / Qave3 <3%, and no change in the flow rate is detected. However, in this case, the setting determination process in step S4 is performed. | Sum of registered flow rate (flow rate 1 + flow rate 2) −current average flow rate Qave4 |> Constant flow rate condition (1) is satisfied and (sum of registered flow rates (flow rate 1 + flow rate 2)> current average flow rate Qave4) The new registered flow rate (flow rate 1 ′) is calculated as the maximum registered flow rate (flow rate 1) − {sum of registered flow rates (flow rate 1 + flow rate 2) −current average flow rate Qave4} = flow rate 1 ′.

  Thereby, a new registered flow rate (flow rate 1 ′) is registered at the timing of T4, and the continuous use time corresponding to the flow rate 1 ′ is set at the timing of T4.

  FIG. 4 is a flowchart of another embodiment, and steps S1 to S3 and S5 to S8 are the same as the processing of FIG. In this embodiment, when it is determined in step S2 that there is no change in the flow rate, the process proceeds to step S41. In step S41, it is determined whether it is 7 minutes before the valve is shut off due to the elapse of the continuous use time. If the determination is NO, the process proceeds to step S5, and if the determination is YES, the process proceeds to step S42. In step S42, a setting determination process is performed in the same manner as in step S4 of FIG. 2, and the process proceeds to step S5.

  With this process, when a shut-off notice is made in the gas leak alarm device, registration of a new registered flow rate and a continuous use time corresponding to this registered flow rate are set. Accordingly, an appropriate continuous use time can be set.

  FIG. 5 is a flowchart of still another embodiment, and steps S1 to S8 are the same as the processing of FIG. In this embodiment, after the determination in step S5, it is determined in step S51 whether the setting determination process (step S4) is a predetermined number of times. The predetermined number of times is, for example, 10 times or 100 times, and if it is not the predetermined number of times, the process returns to the original routine. If it is the predetermined number of times, in steps S6, S7, and S8, a new flow rate is registered, a continuous use time is set, and the timer is restarted to return to the original routine. That is, if the predetermined number is a multiple of 10, the timer is restarted only once in 10 setting determination processes, and if the predetermined number is a multiple of 100, the timer is restarted only once in 100 setting determination processes. Is called.

  Thereby, the continuous update of the continuous use time by every setting like the case of FIG. 2 can be avoided, and appropriate control can be performed based on the registered new flow rate.

  If the re-registration is performed every 15 seconds as in the embodiment of FIG. 2, the timer restart is repeated several times continuously, the continuous use timer is extended, and there is really a gas leak. It may not be shut down with proper continuous use time. Therefore, re-registration of a new flow rate is not performed every 15 seconds every time. As described above, for example, if re-registration is performed at a rate of 10 times or once every 100 times, there was really a gas leak. In such a case, it becomes possible to shut off with an appropriate continuous use time.

  Further, for example, in the example of FIG. 2, when the flow rate is re-registered, the continuous use time is also restarted, and the timer starts measuring from the beginning again. In this logic, when the flow rate decrease of less than 3% continues continuously, the restart is repeated. Although this solves the problem of early shut-off, it will not shut off in an appropriate continuous use time if there is really a gas leak. Therefore, when a flow rate decrease of less than 3% occurs and re-registered to the flow rate 1 ', the timer may not be restarted, and the measurement from the time when the flow rate 1 is registered may be continued. For example, when flow rate 1 (600 L / h) is first used, a timer of 85 minutes starts, and after 45 minutes, a flow rate decrease of less than 3% is confirmed and flow rate 1 ′ is re-registered. If this is the case, the timer continues as it is, instead of restarting the 85-minute timer again. That is, the usage time is cut off 40 minutes after re-registering with the flow rate 1 '. Thereby, when there is really a gas leak, it becomes possible to shut off with an appropriate continuous use time.

DESCRIPTION OF SYMBOLS 10 Microcomputer 20 Flow volume detection part 30 Shut off part 40 Alarm warning signal output part 100 Gas meter

Claims (1)

When the average flow rate of the gas is detected at a predetermined timing and the absolute value of the change amount of the average flow rate exceeds the criterion, a new flow rate corresponding to the detected average flow rate is registered as a registered flow rate, and the average flow rate It has a usage time cutoff function that sets the continuous usage time according to the flow rate and shuts off the gas by closing the shut-off valve when the gas usage time from the time of setting the continuous usage time reaches the continuous usage time. In the gas meter,
When the absolute value of the detected change amount of the average flow rate does not exceed the determination criterion, while performing setting determination processing of continuous use time,
Each time the setting determination process is repeated a predetermined number of times, a new flow rate corresponding to the detected average flow rate is registered, and a continuous use time corresponding to the detected average flow rate is set.

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