JP5070803B2 - Flow rate measuring device and fluid supply system - Google Patents

Description

  The present invention relates to a flow rate measuring device and a fluid supply system that determine the operation of a gas appliance connected to a gas pipe flow path and perform a flow rate measurement for each appliance and a security process for each appliance.

  Conventionally, as shown in FIG. 6, this type of flow rate measuring device includes a gas flow rate measuring unit 1 that measures the flow rate of gas flowing in a gas flow path, and a flow rate increase detecting unit 2 that detects an increase in flow rate from the measurement result. The flow rate increase / decrease detection means 3 for detecting the instantaneous increase / decrease change of the gas flow accompanying the increase of the flow rate, the instrument determination means 4 for determining the start of use of a new gas combustion instrument when the instantaneous increase / decrease change is detected, and the flow rate increase detection means The flow rate registration means 5 for registering the increase in the gas flow rate detected in step 1 as the increase in the gas flow rate associated with the start of use of the new gas combustion appliance (see, for example, Patent Document 1).

With the above configuration, pay attention to the fact that the gas flow rate increases and decreases instantly when it starts to use a new gas combustion device, and it becomes a stable gas flow rate. By determining, the start of use of a new gas combustion appliance can be determined by a simple method, and stop of use can be determined based on a decrease in the flow rate.
JP 2002-174542 A

  However, in the conventional configuration, it is necessary to constantly monitor the start and stop of use of gas appliances, and gas appliances that have already been removed due to failure or are used only in winter, such as heating appliances. However, it has to be discriminated all year round, and the chances of misjudgment increase, which can lead to loss of confidence. In addition, the power consumption required for the discrimination process is generated, and the gas meter driven by the battery has a problem that the battery capacity has to be increased.

  In order to solve the conventional problem, a flow rate measuring unit for measuring a flow rate of a fluid flowing in a flow path, and a differential flow rate at an arbitrary time interval obtained from a change in a used flow rate measured at predetermined time intervals by the flow rate measuring unit. There are provided appliance discriminating means for discriminating an appliance used on the basis of the apparatus and appliance discriminating operation switching means for switching the operation of the appliance discriminating means.

  This makes it possible to switch the instrument discrimination operation of the gas appliance, and when the gas appliance fails and is removed, the appliance discrimination operation can be stopped, or the appliance discrimination operation in summer can be stopped. This eliminates misidentification of appliances that have not been performed, does not impair the reliability of appliance discrimination, and can stop the operation processing of appliance discrimination, thus reducing power consumption and being driven by a battery. In the case of a gas meter, it can be operated for a long time.

  Since the flow rate measuring device of the present invention is provided with the appliance discriminating operation switching means for switching the operation of the appliance discriminating means, the appliance discriminating operation of the gas appliance can be switched, and the appliance discriminating operation can be stopped. An appliance that is not being used is not erroneously discriminated, the reliability of appliance discrimination is not impaired, and the operation processing for appliance discrimination can be stopped, so that power consumption can be reduced.

The first invention is based on a flow rate measuring means for measuring the flow rate of the fluid flowing in the flow path, and a differential flow rate at an arbitrary time interval obtained from a change in the used flow rate measured at predetermined time intervals by the flow rate measuring means. Appliance discriminating means for discriminating the appliance being used, and appliance discriminating operation switching means for switching the operation of the appliance discriminating means, wherein the switching means does not discriminate the operation of the appliance during a predetermined period. When a gas appliance has occurred, the apparatus discriminating function automatically selects the stop and start operation of the appliance discriminating function, and the discriminating means selects the stop and start operation of the appliance discriminating function for each appliance. Since the discriminating operation can be switched and the appliance discriminating operation can be stopped, the discriminating device that is not in use is not erroneously discriminated and the sense of discriminating the appliance is impaired. Together have, it is possible to stop the operation process of the appliance determination, it is possible to reduce power consumption. In addition, when an appliance that does not determine the operation of the appliance has occurred during a predetermined period of time, an erroneous determination to discriminate an appliance that has not been used by automatically selecting stop and start operations of the appliance discrimination function. Another can be reduced. In addition, by selecting the stop and start operation of the appliance discrimination function for each appliance, the appliance discrimination operation of the gas appliance can be switched, and the appliance discrimination operation can be started or stopped for each appliance arbitrarily. It is possible to select the function for determining the appliance in more detail according to the actual usage of the gas appliance and the request of the customer.

In the second aspect of the invention, in particular, the switching means of the flow rate measuring device of the first aspect of the invention further allows the operator or administrator to manually select the stop and start operation of the appliance discrimination function so that the operator or administrator can perform the appliance discrimination function. Start and stop can be changed at any time.

According to a third aspect of the invention, in particular, the switching means of the flow rate measuring device according to the first or second aspect of the invention automatically stops and starts the appliance discrimination function based on a calendar possessed by a microcomputer that controls the discrimination means. For example, the appliance discrimination function can be automatically set in winter and summer, for example, and the work of the manager can be reduced.

According to a fourth aspect of the present invention, in particular, the flow rate measuring device according to the first to third aspects of the present invention includes a temperature measuring unit that measures the temperature of the fluid, and the switching is performed when the measured temperature of the temperature measuring unit exceeds a predetermined value. By automatically selecting the instrument discriminator function stop and start actions, the instrument discriminator function can be automatically selected according to the temperature without distinguishing between winter and summer, so it is necessary to have a calendar function and manual setting mechanism. It is possible to realize automatic setting of the heating season (winter) and the cooling season (summer) with a simple configuration.

In the fifth aspect of the invention, in particular, the temperature measuring means of the flow measuring device of the fourth invention is a temperature measuring means for measuring the temperature of the fluid using the ultrasonic propagation time of the ultrasonic flowmeter as the flow measuring means. By providing, temperature measurement can be realized by applying the measurement principle of ultrasonic flowmeter, and automatic setting of heating season (winter) and cooling season (summer) can be realized with a simple configuration without adding special parts. can do.

In the sixth aspect of the invention, in particular, when the flow rate measuring device of the first to fifth aspects of the invention is used in the fluid supply system, the appliance discrimination operation can be started or stopped individually in each home, Since it is possible to spread the appliance discrimination means not only to one household but also to the whole area, it is possible to promote the spread of appliance gas rate measures, and to set security functions based on the appliance discrimination results as well as the gas fee. Thus, a safe gas supply system can be effectively used as a system for realizing the entire region.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
FIG. 1 shows a block diagram of a gas meter as a flow rate measuring apparatus according to a first embodiment of the present invention.

  In FIG. 1, the gas meter includes an ultrasonic flow meter 7 as a flow rate measuring means for measuring a flow rate flowing through the flow path 6, and an arbitrary time interval based on a flow rate value measured at predetermined time intervals by the ultrasonic flow meter 7. An apparatus discriminating means 8 is provided for determining the differential flow rate, and discriminating the gas appliances 19, 20, 21 used by being connected to the flow path 6 from the characteristics of the time interval differential flow rate. The appliance discriminating operation switching means 9 for switching is provided. Here, 10 is a flow rate calculation means for each appliance for calculating the flow rate used for each of the gas appliances 19, 20, 21, 11 is a gas pipe, 12 is a gas meter as a flow rate measuring device, and 13 is a flow channel when it is desired to stop the gas. 6 is a microcomputer for controlling the operation of each part, 15 is a battery, 16 is a display unit, 17 is an operation unit, 18 is a communication unit, and 19, 20, and 21 are gas pipes. It is a connected gas appliance.

  About the gas meter 12 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, the operation | movement of the instrument discrimination means 8 and the discrimination method are demonstrated using FIG. 2 and FIG.

  The determination of the use start device and the determination of the use stop device is performed using the differential flow rate of the instantaneous flow rate value of the ultrasonic flowmeter 7 measured at intervals of 2 seconds as the predetermined time interval. Here, the differential flow rate uses twice the predetermined time interval as the specific interval, and uses a flow rate difference of 4 seconds as the specific interval differential flow rate. This differential flow rate is referred to as a 4-second differential flow rate.

  Therefore, if the 4-second differential flow rate is greater than the predetermined flow rate value and a positive value, it is determined that some gas appliance has started operating. If the 4-second differential flow rate is greater than the predetermined flow rate value and a negative value, any gas appliance has stopped operating. It is determined that

  Note that the measurement at intervals of 2 seconds and the use of differential flow rates at 4 seconds are one example, and depending on the case, other times may be used, or differential flow rates at various time intervals may be used in combination. Sometimes. However, in the gas meter 12 using ultrasonic waves driven by the battery 15 as in the present embodiment, it is suitable to use a 4-second differential flow rate by 2-second interval measurement from the viewpoint of low power consumption and measurement accuracy. That is, by discriminating with the differential flow rate of 4 seconds, it is possible to detect without overlooking the operation of the instrument.

  If the 4-second differential flow rate is equal to the flow rate value registered as the determination condition, or falls within the flow range, the predetermined flow rate value is determined as a predetermined device, and start device determination or stop device determination is performed. To do.

  For example, when the flow rate used is in a low flow rate range, there are many gas appliances 19, 20, and 21. Therefore, it is difficult to discriminate only by the differential flow rate, and the discrimination is made by looking at the behavior of the differential flow rate. In the flow rate change characteristic diagram of FIG. 2, use of the gas fan heater as the gas appliance 20 is started at time T1, and thereafter, the gas stove as the gas appliance 21 is started at time T2. At time T3, the heating power of the gas stove is adjusted to the low flow rate side, the gas fan heater is stopped at time T4, and the gas stove is stopped at time T5.

  In the case of such a characteristic, from the flow rate change characteristic of the 4-second differential flow rate shown in FIG. 3, at the time T1, the differential flow rate is larger than the flow rate value Qs of the starting instrument determination condition, and the rise of the differential flow rate is gradual. It is determined that the appliance discrimination means 8 is a gas fan heater.

  At time T2, the differential flow rate is larger than the flow rate value Qs of the start instrument determination condition, and the rise of the differential flow rate is abrupt. Therefore, the differential flow rate is determined as a gas stove that matches the start determination condition of the gas stove. These conditions are conditions previously stored in the storage memory, and the gradual rise and fall of the rise is set numerically. These conditions are registered and changed by being rewritten to appropriate conditions in each home.

  Moreover, although it is detected that the differential flow rate falls at time T3, since the absolute value of the differential flow rate is smaller than the flow rate value Qe of the appliance stop determination condition, the differential flow rate is not determined. At time T4, since the absolute value of the differential flow rate exceeds the predetermined threshold value Qe, it is determined that some gas appliance has stopped. Here, it is determined which gas appliance has stopped from the gas fan heater and the gas stove which are the use starting appliances that have been determined to start use.

  Here, since the heating power of the gas stove is adjusted in the middle, it is very difficult to determine which gas appliance is based only on the differential flow rate at the fall. Therefore, when the flow rate value measured at the next measurement time is determined, it can be seen that the absolute flow rate is flowing at a very low flow rate of Q4. Since this flow rate is a small flow rate that is generated only when the heating power of the gas stove is reduced (this value is also set as a determination condition), it can be seen that the gas stove is used between times T4 and T5.

  Therefore, the gas appliance stopped at time T4 is found to be a gas fan heater by removing the gas stove that has been moved from the gas appliance that has been determined to start to the end.

  Moreover, although the differential flow rate falls small at time T5, the threshold value Qb is not exceeded, so that it is not determined as a stop device. However, since the measurement flow rate of the ultrasonic flowmeter after that is zero, the appliance discriminating means 8 discriminates that all the gas appliances 19, 20, and 21 have stopped. Then, it is determined from the remaining starter that the gas stove has stopped at time T5.

  And the flow rate calculation means 10 according to appliances determines the flow rates used by the determined gas appliances 19, 20, 21 and the average flow rate value of the differential flow rate Q1 at the start and the differential flow rate (Q3-Q4) at the stop time, By multiplying the time when the gas appliance is used, that is, the time of T4-T1, it is possible to approximately obtain the use flow rate of the gas fan heater. That is, the use flow rate Q of the gas fan heater is obtained from Q = (Q1 + Q3-Q4) / 2 * (T4-T1) * 3600.

  Further, the integrated flow rate of the gas stove can be obtained by subtracting the integrated flow rate value of the gas fan heater from the total integrated flow rate. Thus, by clarifying the usage time of each gas appliance, the gas flow rate used by each appliance can be calculated individually.

  Next, the appliance discriminating operation switching means will be described.

  The appliance discriminating operation switching means 9 can switch the appliance discriminating operation of the gas appliances 19, 20, and 21 and can stop or start the appliance discriminating operation. An instruction to stop the operation of the appliance discriminating function or an instruction to start it can be sent manually by connecting a switch signal or an electrical terminal provided in the operation unit 17 connected to the microcomputer 14. In addition, it is also possible to manually send an instruction to stop the function of appliance discrimination or start operation by a telegram operation to the communication unit 18 of the gas meter 12 from the setting device of the gas meter 12 having a communication function. In addition, when the device identification operation is started on the display unit 16, the display of “device identification in progress” is displayed on the display unit. can do. The setting switch and the terminal may be installed in the gas meter 12 or may be installed in a separate home display. If it can be set from home, the user can set it individually.

  Such a function for switching the appliance discriminating operation is used in the following cases. For example, in a state in which the gas appliance is no longer used due to a failure, by stopping the function of the appliance discriminating means 8, it is possible to prevent misidentification of an unused gas appliance and impair the reliability of appliance discrimination. This can be prevented. Further, the determination of the gas appliance that does not move is a wasteful process, and the power consumption can be reduced by stopping the operation process of the appliance determination means 8. Since the gas meter 12 has been operating on the battery 15 for 10 years, reducing the power consumption has a very significant meaning, and the capacity of the battery 15 can be reduced, leading to a reduction in the size of the gas meter 12 and a reduction in cost. The effect spreads.

  In addition, the usage situation of gas appliances in each household is different, and there are households that use the appliance discrimination function and those that do not use it. At that time, the appliance discriminating operation switching means 9 arbitrarily starts or stops the appliance discriminating operation, so that the appliance discriminating function is selected in accordance with the actual usage of the gas appliance at each home and the customer's request. be able to.

  Moreover, in the appliance discriminating means 8 for discriminating the operation of a plurality of appliances, the appliance discriminating operation of the gas appliance can be switched by selecting the stop and start operation of the appliance discriminating function for each gas appliance. The appliance discriminating operation can be arbitrarily started or stopped for each appliance, and the appliance discrimination function can be selected in more detail according to the actual usage of the gas appliance and the customer's request.

  Furthermore, by manually selecting the stop and start operation of the appliance discrimination function, the operator or administrator can change the setting of the start or stop of the appliance discrimination function at any time.

  In addition, the appliance discriminating operation switching means 9 can automatically select stop and start operation of the appliance discriminating function. For example, based on a calendar that is one of the timekeeping means managed by the microcomputer 14 that controls the appliance discriminating means 8, it is possible to automatically select the stop and start operation of the appliance discriminating function. For example, if the appliance discriminating function is automatically set in winter and summer, the appliance discriminating function starts operating from December 1 on the basis of the calendar date, and continues to operate until March 31 of the following year. Set as follows. From April 1 to November 30, it can be set to stop the appliance discrimination function, and the appliance discrimination function can be automatically started and stopped. Such automatic setting can reduce the work of the administrator, and can be set without bothering the administrator or the operator. Then, by operating for 1/3 period of 1 year and stopping for 2/3 period, consumption of the battery 15 can be suppressed, and the battery life of the gas meter 12 can be extended. Or it can be operated for 10 years with few batteries 15.

Conversely, it is possible to operate the appliance discrimination function from April 1 to November 30 and stop the appliance discrimination operation from December 1 to March 31 of the following year. The operation period can be set in accordance with the appliance-specific gas charge.

  Further, the appliance discriminating operation switching means 9 automatically selects the stop and start operation of the appliance discriminating function when a gas appliance is generated in which the appliance discriminating means 8 does not discriminate the operation of the gas appliance during a predetermined period. It was set as the structure which can do. For example, there is a possibility that a gas appliance whose operation has not been confirmed by the appliance discriminating means 8 for one month is not actually used or is erroneously discriminated. When it is found that there is such a gas appliance, the instrument discrimination operation of the gas appliance is automatically stopped and the setting is changed so as not to discriminate the appliance. As a result, it is possible to reduce misidentification of an instrument that is not used, leading to an improvement in reliability.

  The above-mentioned “one month” is an example, and may be one week or two weeks, and can be changed according to each use situation. Although the calendar managed by the microcomputer 14 has been described, in the case where the instrument discriminating means 8 is built in an external unit outside the gas meter, the external unit manages the calendar managed by the microcomputer 14 of the gas meter. Even a calendar to be set can be set by a calendar managed by one of them, and automatic setting by the calendar becomes possible.

  In addition, the case where the device discrimination operation is manually switched by the device discrimination operation switching means 9 and the case where the operation is automatically switched have been described. However, both manual and automatic settings can be used. It is.

  When such a flow rate measuring device is used in a fluid supply system, the appliance discriminating operation can be started or stopped individually in each home, and the appliance discriminating means 8 is provided not only in one home but also in the entire area. As a result, it is possible to promote the spread of instrument gas charge measures, and realize a safe gas supply system for the entire region by setting safety functions based not only on gas charges but also on instrument discrimination results. It can be effectively used as a system to perform customer service such as a separate fee.

  Although the above description has been given of the case where an ultrasonic flowmeter is used, it is obvious that the same effect can be obtained with other instantaneous flow rate measuring means. By using an instantaneous flow meter, the measurement timing can be set at equal time intervals regardless of the flow rate, so that any instrument with any flow rate can be discriminated with good timing. Moreover, although demonstrated with the gas meter 12, it is used also for an industrial flow meter and a water meter for the discrimination | determination of the instrument used connected to the downstream of a flow measuring device, the measurement of the usage flow according to an instrument, and the security of an instrument. Can do.

  Moreover, although the example about the fee for each appliance has been described, the appliance discrimination information can also be used for a security function for safely supplying gas. In this case, the security function for each gas appliance can also be switched by switching the appliance discrimination operation by the appliance discrimination operation switching means 9. For example, it is possible to set the continuous use permission time for each gas appliance, but when the appliance discrimination operation is started, the continuous use time limit for each gas appliance is enabled and the appliance discrimination function is stopped. The continuous use time limit for each gas appliance can also be stopped. In addition, when the appliance discrimination operation is automatically started, the security function is automatically switched to the security function based on appliance discrimination. As described above, the appliance discrimination operation switching means 9 can also switch the security function, and the appliance discrimination operation and the security function can be smoothly coordinated.

  Furthermore, the timing for manually switching the instrument discrimination operation by the instrument discrimination operation switching means 9 can be freely selected at the time of meter reading, the inspection timing of the gas cylinder, the replacement timing, etc. High system configuration.

  Moreover, although the apparatus discrimination | determination means 8 demonstrated by the method of specifying a gas appliance only by the flow value of a flow measurement means, the method of receiving a signal from a gas appliance and specifying a gas appliance, or the flow volume of an individual gas appliance is used. It is clear that the same effect can be obtained by using the configuration and mechanism of the appliance discriminating operation switching means as other appliance discriminating means combining them, including the method of measuring and specifying the gas appliance. In addition, selection of each appliance discriminating means can also be considered as a function of the appliance discriminating operation switching means.

(Embodiment 2)
FIG. 4 shows temperature measurement for measuring the temperature by acquiring propagation time information from the instrument discrimination operation switching means of the flow rate measuring apparatus according to the second embodiment of the present invention and the ultrasonic flowmeter as the flow rate measuring apparatus. It is a block diagram which shows a structure with the means 22. FIG. Only differences from the first embodiment will be described.

  First, the temperature measuring means 22 shown in FIG. 4 will be described.

  As shown in FIG. 5, the ultrasonic flowmeter 7 propagates ultrasonic waves between a pair of ultrasonic transducers that are opposed to the flow path 6 at an angle θ and measures the propagation time with an electronic circuit. The flow rate is calculated from the following formula.

For example, in the flow path 6 configured as shown in FIG. 5, when the time T <b> 1 that propagates from the first piezoelectric vibrator 23 as the ultrasonic vibrator toward the second piezoelectric vibrator 24 is measured,
T1 = L / (C + V cos θ)
It becomes. Further, when the time T2 that propagates from the second piezoelectric vibrator 24 toward the first piezoelectric vibrator 23 is measured,
T2 = L / (C−Vcos θ)
It becomes. Here, V is the flow velocity in the flow path 6, C is the speed of sound, and θ is the inclination angle. And if the difference of the reciprocal number of T1 and T2 is taken, the flow velocity V will be calculated | required from T1 and T2 like following Formula.

1 / T1-1 / T2 = 2V cos θ / L
V = (L / 2 cos θ) · (1 / T1-1 / T2)
The flow rate Q is calculated by multiplying the flow velocity V by the cross-sectional area S of the flow path 6 and the flow rate correction coefficient α.

Q = α ・ S ・ V
Here, the flow rate correction coefficient α is a correction coefficient for compensating for a difference from the correct flow rate.

  A method for realizing the temperature measuring means by using this calculation principle will be described. By taking the sum of the reciprocals of the propagation times T1 and T2, the term of the flow velocity V is eliminated, and the sound velocity C can be obtained as in the following equation.

1 / T1 + 1 / T2 = 2C / L
C = (L / 2) · (1 / T1 + 1 / T2)
Therefore, for example, when the fluid is air, if the fluid temperature is T,
C = 331.5 + 0.61T
The temperature T can be obtained from the following equation.

  In the present embodiment, the ultrasonic flowmeter 7 and the microcomputer 14 are connected and described in a simplified manner, but the microcomputer 14 receives the propagation time information from the ultrasonic flowmeter 7 and the microcomputer 14 determines the temperature. It is configured to calculate.

  Next, the operation of the appliance discrimination operation switching means 9 that controls the operation of the appliance discrimination means 8 using the measured temperature will be described.

  As described above, when the measured temperature of the temperature measuring means 22 for measuring the temperature of the fluid using the propagation time of the ultrasonic flowmeter 7 becomes a predetermined value or more, the appliance discriminating operation switching means 9 automatically performs the appliance discriminating function. By selecting the stop and operation, it is possible to automatically select the operation of the appliance discrimination function according to the temperature without distinguishing between winter and summer, so there is no need for a calendar function or manual setting mechanism, and a simple configuration The automatic setting of heating season (winter) and cooling season (summer) can be realized.

  For example, when it is desired to perform the appliance discrimination operation only during the heating season, the appliance discrimination operation can be stopped when the temperature measured by the temperature measuring means 22 is 18 ° C. or higher. If it is desired to discriminate the appliance during the cooling season, it is possible to set the appliance discriminating operation to start when the measured temperature reaches 28 ° C. or higher. However, since the temperature may fluctuate, it is necessary to devise a method that allows the appliance discrimination operation to be performed stably with a wide threshold value for the set temperature.

  In addition, by realizing the temperature measurement means 22 that measures the temperature of the fluid using the ultrasonic wave propagation time of the ultrasonic flowmeter 7, the heating season (winter season) or the like can be achieved with a simple configuration without adding special parts. Automatic setting of the cooling season (summer) can be realized.

  In this way, the gas appliance can be determined from the usage state of the use start device and the use stop device, or the use state of the flow rate difference before and after that, and the flow rate for each device can be determined from the flow rate value and the time of the use state. Can be calculated. As a result, customer services such as appliance charges can be realized.

  In addition, although the above explanation was explained with the gas meter, in the industrial flow meter and the water meter, similarly, it is used for the discrimination of the used appliance connected to the downstream side of the flow measuring device, the measurement of the used flow rate for each appliance, and the security of the appliance. Can be used.

  As described above, the flow rate measuring device according to the present invention can be applied to gas meters, industrial flow meters, and water meters.

The block diagram of the flow measuring device in Embodiment 1 of the present invention. Flow pattern diagram measured with the same flow measuring device Differential flow pattern diagram measured by the same flow measurement device Block diagram of a flow rate measuring device in Embodiment 2 of the present invention Configuration diagram of ultrasonic flowmeter used in the same flow measurement device Block diagram of a conventional flow measurement device

Explanation of symbols

6 Channel 7 Ultrasonic flow meter (flow rate measuring means)
8 Appliance discriminating means 9 Appliance discriminating operation switching means 11 Gas pipe line 12 Gas meter (flow rate measuring device)
DESCRIPTION OF SYMBOLS 13 Flow path shut-off valve 14 Microcomputer 15 Battery 16 Display part 17 Operation part 18 Communication part 19, 20, 21 Gas appliance 22 Temperature measurement means

Claims (6)

A flow rate measuring means for measuring the flow rate of the fluid flowing in the flow path;
Discriminating means for discriminating an instrument used on the basis of a differential flow rate at an arbitrary time interval obtained from a change in usage flow rate measured at predetermined time intervals by the flow rate measuring unit;
Switching means for switching the operation of the determination means,
The switching means automatically selects the stop and start operation of the appliance discrimination function when an appliance occurs in which the discrimination means does not discriminate the operation of the appliance in a predetermined period ,
The determination unit is a flow rate measuring device that selects a stop and start operation of the instrument determination function for each instrument . The flow rate measuring apparatus according to claim 1, wherein the switching unit further manually selects a stop and start operation of the appliance discrimination function. Said switching means, the flow rate measuring apparatus according to claim 1 or 2 to select the start and stop operation of automatically the appliance determination function on the basis of the calendar microcomputer for controlling said discrimination means held. Comprising a temperature measuring means for measuring the temperature of the fluid, the temperature when the measured temperature of the measuring means exceeds a predetermined, claims 1 to 3 wherein the switching means selects the start and stop operation of the automatic appliance determination function The flow measuring device according to any one of the above. The flow rate measuring device according to claim 4, wherein the flow rate measuring unit is an ultrasonic flow meter, and measures the temperature of the fluid using an ultrasonic propagation time of the ultrasonic flow meter. A fluid supply system using the flow rate measuring device according to any one of claims 1 to 5.

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