JP5006492B2 - Flow meter with gas leak detection function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flow meter having a gas leakage detection function for detecting the presence or absence of leakage in a gas supply path based on the flow rate of gas flowing through the gas supply path.
[0002]
[Prior art]
In general, a gas meter arranged in a gas supply path for supplying fuel gas not only has a function of measuring the consumption amount of fuel gas in a gas consuming device connected to the downstream side of the gas meter, but also safely supplies the fuel gas. It has various security functions for use. One of these types of security functions is to monitor the flow rate of gas passing through the flow rate detection means provided in the gas supply path, and detect the flow rate when the flow rate is detected continuously throughout the specified leakage judgment period. There is a leak detection function for determining that there is a leak in the gas supply path on the downstream side of the means. For example, it is adopted in a gas meter (so-called microcomputer meter) incorporating a microcomputer. The microcomputer meter not only has the function of measuring the gas consumption in gas consuming equipment, but also detects the presence or absence of an abnormality such as a leak in the gas supply path and shuts off the gas supply path when an abnormality is detected. A function for notifying the occurrence of an abnormality is provided.
[0003]
In the microcomputer meter, the presence or absence of leakage in the gas supply path is determined based on the flow rate of the gas passing through the flow rate detection means. For example, a flow rate detection means that generates one pulsed flow signal every time the amount of gas passing through reaches a specified fixed amount (that is, the amount of gas passing through the flow rate detection means is represented by the time interval at which the flow rate signal is generated). This type of microcomputer meter uses a certain unit time (for example, one hour unit) as a monitoring period, and generates a flow signal every monitoring period. If there is at least one monitoring period in which a flow rate signal is generated, when such a monitoring period continues over the entire period of a specified leakage determination period (for example, 30 days), the downstream of the flow rate detection means It is determined that there is a leak in the gas supply path on the side. When the leakage of the gas supply path is detected, the leakage of the gas is notified or the gas supply path is shut off by auditory means or visual means.
[0004]
On the other hand, depending on the gas consuming equipment, there is a gas consuming equipment that operates intermittently at a time interval shorter than the monitoring period described above, and is used continuously throughout the entire leakage determination period. If it is used, it is erroneously determined that there is a leak even when there is no leak in the gas supply path on the downstream side of the flow rate detection means.
[0005]
In such a case, it is considered that the problem can be solved by using a highly sensitive flow rate detection means in which the minimum detectable flow rate is made smaller. For example, by using flow rate detection means that can set the monitoring period to about 5 minutes by converting the flow velocity into the passage amount of the fluid, an appropriate threshold value is set for the passage amount of the fluid, and the threshold value is exceeded for each monitoring period. It is determined whether or not a period is included, and when a monitoring period including a period exceeding the threshold continues throughout the leakage determination period, it is determined that there is a leak in the gas supply path. In other words, even if the gas consuming device operates intermittently, there is a high possibility that it has been stopped for about 5 minutes. Therefore, if there is no leakage in the gas supply path, the flow rate may be detected over the leakage determination period. It is possible to prevent erroneous determination that leakage has occurred even though leakage has not occurred. In this way, it is considered possible to clearly distinguish between the use of gas consuming equipment and leakage in the gas supply path.
[0006]
[Problems to be solved by the invention]
However, when a highly sensitive flow rate detection means is used, it is easy to detect a noise component, and there is a possibility of erroneous determination due to the noise component. For example, when the gas supply path between the flow rate detection means and the gas consuming equipment is relatively short, pressure fluctuations in the gas supply path due to the use of the gas consuming equipment may occur, and pressure fluctuations such as in a gas engine heat pump When gas consuming equipment that generates gas is installed, pressure fluctuations in the gas supply path may occur, and convection may also occur due to temperature differences inside the flow rate detection means and gas supply path. In some cases, the flow rate is detected by the flow rate detection means even when the consumer device is not used. In addition, since the zero point of the flow rate detection means may fluctuate over time, the flow rate detection means that even if there is no flow rate due to the influence of the zero point fluctuation (zero point drift), especially in the highly sensitive flow rate detection means The flow rate may be detected by the means. Thus, when the flow rate is detected by the flow rate detection means even though there is no actual flow rate, there is a possibility that the flow rate is integrated.
[0007]
The present invention has been made in view of the above-mentioned reasons, and its object is to detect noise in the gas supply path downstream of the flow rate detection unit without any error by using a highly sensitive flow rate detection unit, while reducing noise. An object of the present invention is to provide a flow meter having a gas leak detection function that prevents components from being removed and accumulated as a gas use flow rate even though a gas consuming device is not substantially used.
[0008]
[Means for Solving the Problems]
  According to the first aspect of the present invention, there is provided a flow rate detecting means for detecting a flow rate of the gas flowing through the gas supply path, a prescribed measurement reference value, a dead reference value that is equal to or less than the measurement reference value, and a gas detected by the flow rate detection means A flow rate determining unit that determines the magnitude of the flow rate, a flow rate integrating unit that integrates the gas flow rate as a gas usage flow rate during a period in which the gas flow rate is determined to be equal to or greater than the measurement reference value, and a flow rate integrating unit. An output means for outputting the integrated integrated value as a gas use flow rate, and a period during which the gas flow rate is determined to be equal to or greater than the insensitive reference value by the flow rate determination means is considered to be continuing, and that period is a specified leakage determination period Leakage determining means for determining that leakage has occurred in the gas supply path downstream of the flow rate detecting means, A reference value setting means for setting the measurement reference value to be variable and not less than the insensitive reference value;It is characterized by providing.
  According to a second aspect of the present invention, there is provided a flow rate detection means for detecting a flow rate of gas flowing through the gas supply path, a specified measurement reference value, a dead reference value equal to or less than the measurement reference value, and a gas detected by the flow rate detection means. A flow rate determining unit that determines the magnitude of the flow rate, a flow rate integrating unit that integrates the gas flow rate as a gas usage flow rate during a period in which the gas flow rate is determined to be equal to or greater than the measurement reference value, and a flow rate integrating unit. An output means for outputting the integrated integrated value as a gas use flow rate, and a period during which the gas flow rate is determined to be equal to or greater than the insensitive reference value by the flow rate determination means is considered to be continuing, and that period is a specified leakage determination period When the gas flow rate reaches the flow rate detection means, a leak determination means for determining that a leak has occurred in the gas supply path on the downstream side of the flow rate detection means, and a gas flow rate fluctuation detected by the flow rate detection means. Obtains the estimated value of the minimum flow rate of the gas consumption device based on over emissions, characterized in that it comprises a reference value setting means for setting the metric value is regulated below and above insensitive reference value this estimate.
The inventions of claim 1 and claim 2In the configuration, the flow rate at which the gas flow rate in the gas supply path is equal to or greater than the measurement reference value is obtained as the gas use flow rate, and the flow rate equal to or greater than the dead standard value set to be equal to or less than the measurement reference value is used for detection of leakage in the gas supply path. By using the highly sensitive flow rate detection means, it is possible to detect leaks in the gas supply path downstream of the flow rate detection means without error, but by appropriately setting the measurement reference value and the dead reference value, Noise components caused by disturbances such as fluctuations, pressure fluctuations, and convection can be removed to prevent accumulation in the gas flow rate even when the gas consuming equipment is not used. Become.
In addition, the measurement reference value can be adjusted according to the usage state of the gas consuming device. In other words, by setting a measurement reference value that is greater than the dead reference value for detecting gas leakage, it is possible to accurately detect the gas flow rate in the gas consuming device while avoiding the influence of noise components. It becomes possible.
[0009]
  Claim 3The invention of claim 1Or claim 2In the invention, the measurement reference value is set to be equal to or less than a minimum flow rate consumed by a gas consuming device connected to the downstream side of the flow rate detecting means in the gas supply path. According to this configuration, in addition to the operation of the invention of claim 1, the flow rate used in the gas consuming device can be reliably integrated by the flow rate integrating means.
[0012]
  Claim 4The invention of claim 1 to claim 1Claim 3According to the present invention, it is characterized by comprising usage display means for indicating that the gas is passing during a period in which the flow rate of the gas is determined to be equal to or higher than the measurement reference value. According to this configuration, the period during which the gas consuming device is used can be accurately displayed by the usage display means.
[0013]
  Claim 5The invention of claim 1 to claim 1Claim 4According to the invention, there is provided a selection means capable of selecting an inspection mode for matching the measurement reference value with the dead reference value. According to this configuration, by passing an appropriate flow rate through the flow rate detection means at the time of inspection at the factory, it is possible to inspect whether there is an abnormality in the flow rate detection means and to know the leakage detection sensitivity.
[0014]
The gas used as the main application of the present invention is a fuel gas, but the technical idea of the present invention is not limited to the fuel gas but can be applied to any gas. Moreover, it is also possible to divert the technical idea of this invention about the leakage of a liquid like the water leak in a waterworks, for example.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
In the present embodiment, in order to remove noise components, a measurement reference value and a dead reference value less than or equal to the measurement reference value are set, and the flow rate judging means sets an instantaneous flow rate that is less than the measurement reference value and greater than or equal to the dead reference value to the flow rate. An instantaneous flow rate that is equal to or greater than the measurement reference value is used in the calculation as a gas flow rate for determining whether or not the gas supply path is leaked downstream of the detection means. The configuration and operation of this embodiment will be specifically described below.
[0016]
In the present embodiment, an example of application to a gas meter incorporating a microcomputer is shown. As shown in FIG. 1, the gas meter 1 is provided with a flow rate detection means 11 for detecting the flow rate of the gas passing through the gas supply path, and the flow rate detection means 11 has a relatively short time interval or a continuous flow rate. Those that detect are used. The instantaneous flow rate (sampling value at fixed time intervals) measured by the flow rate detection unit 11 is input to the flow rate determination unit 12, and the magnitudes of the measurement reference value and the dead reference value defined in advance and the instantaneous flow rate are compared. The dead reference value is set to be equal to or less than the measurement reference value and about the detection lower limit value of the flow rate detection means 11. In addition, the use of gas with a noise component as an instantaneous flow rate detected at the time of occurrence of convection caused by pressure fluctuations in the gas supply path due to the use of gas consuming equipment or temperature differences in the flow rate detection means 11 or in the gas supply path The measurement reference value is set to be equal to or less than the minimum flow rate consumed by the gas consuming device provided on the downstream side of the gas meter 1 so that it can be removed from the flow rate. Therefore, the instantaneous flow rate that is less than the dead reference value is ignored.
[0017]
When the instantaneous flow rate detected by the flow rate detection unit 11 is equal to or greater than the measurement reference value, the instantaneous flow rate is input to the flow rate integration unit 13 as the flow rate integration unit, and an integrated value of the flow rate corresponding to the gas use flow rate is obtained. That is, when gas is consumed substantially in the gas consuming device, the gas flow rate during that period is integrated in the flow rate integrating unit 13, and the integrated value in the flow rate integrating unit 13 is used as the gas usage flow rate in the gas consuming device. Displayed by the integrated value display means (output means) 14. The integrated value display means 14 is realized by a liquid crystal display, for example.
[0018]
On the other hand, when the instantaneous flow rate is equal to or greater than the dead standard value, the instantaneous flow rate is input to the leakage determination means 16. The leakage determination means 16 measures the period during which the instantaneous flow rate is equal to or greater than the insensitive reference value, and when this period reaches the specified leakage determination period, leakage occurs in the gas supply path downstream of the flow detection means. Judge that it is. When it is determined that gas leakage has occurred in the gas supply path, a command is given to the shut-off means 17 such as an electromagnetic valve inserted into the gas supply path on the upstream side or downstream side of the flow rate detection means 11, and the gas meter 1 The gas supply path on the downstream side is shut off, and a notification means 18 such as a light emitting diode is used to notify that a gas leak has occurred. In the present embodiment, an example in which both the blocking unit 17 and the notification unit 18 are provided is shown, but a configuration in which only one of them is provided can be employed.
[0019]
More specific description will be given below. The presence or absence of gas leakage in the gas supply path is determined by the following procedure as shown in FIG. As described above, the instantaneous flow rate is output by the flow rate detection means 11 at regular intervals (sampling period: for example, 2 seconds) (S1). The instantaneous flow rate Q1 is input to the flow rate determination means 12, and it is determined whether or not the flow rate is substantially detected (S2). That is, it is determined whether or not a gas flow is substantially detected in the gas supply path by removing a noise component such as a fluctuation of a zero point or a dark noise component in the flow rate detection means 11. Specifically, the instantaneous flow rate Q1 is compared with the dead reference value Q3 in the flow rate determining means 12, and if the instantaneous flow rate Q1 is equal to or greater than the dead reference value Q3, a leak occurs in the gas supply path downstream of the flow rate detecting means 11. It is considered that gas is consumed by gas consuming equipment. In addition, if the instantaneous flow rate Q1 is less than the dead standard value Q3, it is considered that no substantial flow rate has occurred, and there is no use of gas in the gas consuming device, and no leakage of the gas supply path has occurred, Alternatively, it is determined that the blocking means 17 is blocked. As described above, in the present embodiment, the leak determination means 16 is provided with a timer function, and the timer function is such that the instantaneous flow rate Q1 is not less than the dead reference value Q3 since the instantaneous flow rate Q1 has become the dead reference value Q3 or more. The period C2 during which the state is continued is counted.
[0020]
When the instantaneous flow rate Q1 is less than the dead reference value Q3, it is first determined whether the shut-off means 17 is in an open state or a shut-off state (S3). Since it is not supplied, the timing of the period C2 by the timer function is stopped (S4). In this case, the value of the period C2 is held as it is. On the other hand, if the shut-off means 17 is in the open state in step S3, it is presumed that the gas in the gas consuming device is not used and the gas supply path is not leaked. The timing is stopped and the period C2 is initialized (S5). In short, since the instantaneous flow rate Q1 is less than the dead reference value Q3, the period C2 is initialized without performing the time measurement by the timer function.
[0021]
Even when the instantaneous flow rate Q1 detected in step S1 is equal to or greater than the dead reference value Q3, it is first determined whether the shut-off means 17 is in the open state or the cut-off state (S6), and the instantaneous flow rate Q1 is equal to or greater than the dead reference value Q3. If the shutoff means 17 is in the shutoff state despite the fact that the flow rate is substantially detected, an abnormality has occurred in the system including the flow rate detection means 11 and the shutoff means 17, so that the notification means 18. To notify that there is an abnormality in the flow rate detecting means 11 or the blocking means 17 (S7).
[0022]
When the instantaneous flow rate Q1 is greater than or equal to the dead reference value Q3 in step S2 and the shut-off means 17 is open in step S6, gas is consumed by the gas consuming device or leakage has occurred in the gas supply path. Therefore, the time measurement by the timer function is started from the time when the instantaneous flow rate Q1 becomes equal to or greater than the dead reference value Q3 in the leakage detection means 16, and thereafter, while it is determined in step S6 that the shut-off means 17 is open. Timekeeping by the timer function is continued (S8). Here, if step S8 is repeated, the time interval for passing step S8 becomes the sampling period of the instantaneous flow rate Q1, so that in step S8, if the number of passes is counted, the period C2 is substantially counted. Equivalent to.
[0023]
By the way, if the instantaneous flow rate Q1 is not less than the dead reference value Q3 and exceeds the measurement reference value Q2, it can be considered that gas is consumed by the gas consuming device. It is compared with the value Q2 (S9). If the instantaneous flow Q1 is greater than or equal to the measurement reference value Q2, the instantaneous flow rate Q1 is given to the flow rate integrating means 13 (S10), and the flow rate integrating means 13 obtains the flow rate in the sampling period by multiplying the instantaneous flow rate by the sampling period. Then, an integrated value obtained by integrating the newly obtained flow rate with the integrated value obtained in the past in the flow rate integrating means 13 is obtained (S11). The newly obtained integrated value is stored in a memory (not shown) constituting the flow rate integrating means 13 and displayed on the integrated value display means 14 (S12). This integrated value is an integrated value of the flow rate of the gas consumed by the gas consuming device, and is used as a gas use flow rate at the consumer. Thereafter, the timed period C2 is compared with a prescribed leakage determination period T2 (for example, 30 days) (S13), and if the period C2 has not reached the leakage determination period T2, the next instantaneous flow rate Q1 is captured (S1). ). Further, when the period C2 reaches the leakage determination period T2, it is considered that leakage has occurred in the gas supply path downstream of the flow rate detection means 11, so the interruption means 17 is interrupted and an alarm is notified by the notification means 18. (S14).
[0024]
  When it is determined in step S9 that the instantaneous flow rate Q1 is less than the measurement reference value Q2 (Q1 <Q2), the instantaneous flow rate Q1 is not integrated. The process proceeds to S13, where the timed period C2 is compared with the specified leakage determination period T2, and if the period C2 has not reached the leakage determination period T2, the next instantaneous flow rate Q1 is taken in (S1), and the period C2 leaks. Judgment period T2 reacheddoingSometimes the shut-off means 17 is shut off and the alert means 18 alerts the alarm. The leakage determination period T2 is set sufficiently longer than the time when the gas consuming device is used once, and is set to 30 days, for example.
[0025]
Here, when the leakage determining means 16 determines that there is a leak in the gas supply path, the blocking means 17 is shut off and simultaneously notified by the notifying means 18, but after the notification by the notifying means 18 is performed for a certain period of time. The gas supply path may be blocked by the blocking means 17. It is also possible to adopt a configuration in which only one of blocking by the blocking unit 17 and notification by the notification unit 18 is performed. Alternatively, the notifying unit 18 may be configured not only to visually notify but also to audibly alarm.
[0026]
By the way, since it is obligated by the regulations to detect a leak with a flow rate of 3 L / h or more (here, L indicates liter), for example, the dead reference value Q3 is 1 L / h with respect to the instantaneous flow rate Q1. It is possible to set so as to correspond to. That is, the dead standard value Q3 is set to remove a noise component, and it is possible for a general consumer to set the dead standard value Q3 as a fixed value. However, the measurement reference value Q2 is set based on the minimum flow rate used in the gas consuming device, and this flow rate varies depending on the gas consuming device. For example, the seed fire is 10 L / h, and the gas table stove is 30 L / h. In short, since the measurement reference value Q2 differs depending on the customer, the measurement reference value Q2 is preferably variable.
[0027]
Therefore, in this embodiment, the reference value setting means 12a is added to the flow rate determination means 12, and the measurement reference value Q2 can be adjusted. The reference value setting unit 12a may employ a configuration in which the measurement reference value Q2 is adjusted by hand operation, or a configuration in which the reference value setting unit 12a is set by communication from the outside. Alternatively, based on the fluctuation pattern of the instantaneous flow rate Q1 detected by the flow rate detection means 11, an estimated value of the minimum flow rate in the gas consuming device used by the consumer is obtained, and the measurement standard is set to an appropriate value below this estimated value. A function of learning to set a value may be provided in the reference value setting unit 12a. In this case, it is desirable that the initial value of the measurement reference value Q2 is set to a relatively small value and is changed to an appropriate value based on the fluctuation pattern of the instantaneous flow rate Q1. Since it is an indispensable condition that the measurement reference value Q2 is equal to or greater than the dead reference value Q3, the reference value setting means 12a needs a means for restricting the measurement reference value Q2 from being set to the dead reference value Q3 or less. For example, when a value less than the dead reference value Q3 is selected as the measurement reference value Q2, the measurement reference value Q2 is made smaller than the dead reference value Q3 by restricting the measurement reference value Q2 to coincide with the dead reference value Q3. Can be prevented.
[0028]
The flow rate determination means 12 is also provided with a usage display means 12b indicating that the gas is passing through the flow rate detection means 11 by displaying a period during which the instantaneous flow rate Q1 is equal to or greater than the measurement reference value Q2. Means 12b can indicate when the gas consuming device is using the gas. That is, when the integrated value display means 14 displays the integrated value as a numerical value, the integrated value display means 14 cannot know whether or not gas is passing unless the display of the minimum digit changes. Gas passage is indicated by means 12b. Since the measurement reference value Q2 is set to be larger than the noise component, the usage display means 12b can accurately indicate that the gas consuming device is in use without causing erroneous display due to the influence of the noise component.
[0029]
In the present embodiment, in addition to the normal mode for detecting the flow rate of gas used in the gas consuming device, a selection unit 19 is provided that enables selection of an inspection mode for inspecting the performance of the flow rate detection unit. The reference value Q2 is set to coincide with the dead reference value Q3. In other words, in the inspection mode, the integrated value display means 14 displays the integrated value during the period in which the instantaneous flow rate Q1 is equal to or greater than the dead reference value Q3. If the flow rate Q1 is inspected as a predetermined value, it can be confirmed whether or not the flow rate detection means 11 operates normally, and the sensitivity to gas leakage can also be confirmed.
[0030]
As the flow rate detection means 11 used in the present embodiment, in addition to the ultrasonic flow meter, if the flow rate in a short time (instantaneous flow rate) can be detected, a phenomenon in which heat is taken away by the flow of the fluid is used. A heat conduction type flow meter, a fluidic type flow meter using fluidic oscillation, and other configurations such as a membrane type flow meter and a turbine type flow meter can be used.
[0031]
Here, when the flow rate detection means 11 is roughly classified, a flow rate signal is detected every time a fixed volume passes like a flow rate detection device such as an ultrasonic flow meter and a continuous flow rate detection such as a membrane flow meter. Output one pulse.
[0032]
  In the above-described example, the flow rate detecting means 11 that continuously detects the flow rate based on the flow velocity is assumed, and the instantaneous flow rate Q1 is obtained as flow velocity × channel cross-sectional area. Therefore, if the sampling cycle is 2 seconds, the flow rate can be obtained by multiplying the instantaneous flow rate Q1 that is a sampling value by the sampling rate 2 seconds that is the sampling value in the flow rate determination unit 12 or the leakage determination unit 16. It is also possible to obtain an average of a plurality (a certain number) of instantaneous flow rates Q1 that are sampling values as a moving average, and use the moving average value instead of the instantaneous flow rate Q1. If a moving average value is used instead of the instantaneous flow rate Q1, noise that occurs instantaneously can be removed. That is, in the configuration in which the leakage of the gas supply path is determined by comparing the period in which the instantaneous flow rate Q1 is equal to or greater than the dead reference value Q3 as described above with the leakage determination period T2, the instantaneous flow rate Q1 every 2 seconds. Is used, the instantaneous flow rate Q1 may instantaneously become less than the dead reference value Q3 even though leakage occurs in the gas supply path due to pressure fluctuation or the like. Therefore, if the moving average value is used instead of the instantaneous flow rate Q1, the instantaneous fluctuation amount of the instantaneous flow rate Q1 can be removed.Gas supply pathWhen leakage occurs, it is possible to continue the state where the instantaneous flow rate Q1 is equal to or greater than the dead reference value Q3. That is, the leakage of the gas supply path can be detected more reliably by using the moving average value than by using the instantaneous flow rate Q1 as it is.
[0033]
On the other hand, when using the flow rate detection means 11 that outputs one pulse as a flow rate signal for every fixed volume, such as a membrane flow meter, the flow rate signal P depends on the gas flow rate as shown in FIG. The generated time intervals I1 to In change. That is, when the flow rate detection means 11 divides the volume V0 for generating one flow rate signal by the time interval Ii (i = 1, 2,..., N) for generating the flow rate signal P (V0 / Ii), A value corresponding to the flow rate Q1 can be obtained. That is, when this type of flow rate detection means 11 is used, the value obtained as described above may be used instead of the instantaneous flow rate Q1. Further, since this value does not have an instantaneous change like the instantaneous flow rate Q1, it is not necessary to use a moving average value, and a value obtained by multiplying the number of generated flow rate signals P by a fixed volume is an integrated value of gas that has passed. Therefore, the flow rate integrating means 13 can be configured to count the number of generated flow rate signals P and multiply the counted number of generated signals by the volume.
[0034]
【The invention's effect】
  Claim 1In the configuration of the invention of claim 2,High sensitivity is obtained because the gas flow rate in the gas supply path is equal to or higher than the measurement reference value, and the flow rate above the measurement reference value is used for detection of leakage in the gas supply path. The flow rate detection means can detect leaks in the gas supply path downstream of the flow rate detection means without error, but by setting the measurement reference value and the dead reference value appropriately, the zero point fluctuation, pressure The advantage of eliminating noise components due to disturbances such as fluctuations and convection, so that it is possible to prevent accumulation by including in the gas flow rate even though the gas consuming equipment is not used. There is.
In addition, the measurement reference value can be adjusted according to the usage state of the gas consuming device. In other words, by setting a measurement reference value that is greater than the dead reference value for detecting gas leakage, it is possible to accurately detect the gas flow rate in the gas consuming device while avoiding the influence of noise components. It becomes possible.
[0035]
  Claim 3The invention of claim 1Or claim 2In the invention, the measurement reference value is set to be equal to or less than the minimum flow rate consumed by the gas consuming device connected to the downstream side of the flow rate detection means in the gas supply path. In addition, there is an advantage that the flow rate used in the gas consuming device can be reliably integrated by the flow rate integration means.
[0038]
  Claim 4The invention of claim 1 to claim 1Claim 3In the invention of the above, since there is a use display means for indicating that the gas is passing during a period when the flow rate of the gas is determined to be greater than or equal to the measurement reference value by the flow rate determination means, the period when the gas consuming device is used Can be accurately displayed by the use display means.
[0039]
  Claim 5The invention of claim 1 to claim 1Claim 4In the invention of the present invention, there is provided a selection means capable of selecting an inspection mode for matching the measurement reference value with the dead reference value. Therefore, an abnormality of the flow detection means can be caused by passing an appropriate flow rate through the flow detection means during inspection in a factory. In addition, it is possible to know the detection sensitivity of leaks.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is an operation explanatory view of the above.
FIG. 3 is an operation explanatory diagram of another configuration example.
[Explanation of symbols]
1 Gas meter
11 Flow rate detection means
12 Flow rate judging means
12a Reference value setting means
12b Usage display means
13 Flow rate integration means
14 Integrated value display means
16 Leakage determination means
17 Blocking means
18 Notification means
19 Selection means

Claims (5)

A flow rate detecting means for detecting a flow rate of the gas flowing through the gas supply path, and determining a magnitude of a predetermined measurement reference value and a dead reference value equal to or less than the measurement reference value and a gas flow rate detected by the flow rate detecting means; A flow rate determination unit, a flow rate integration unit that integrates a gas flow rate as a gas use flow rate during a period in which the gas flow rate is determined to be greater than or equal to a measurement reference value by the flow rate determination unit, and an integrated value integrated by the flow rate integration unit Output means for outputting as a used flow rate, and the flow rate detecting means when the period during which the flow rate of the gas is determined to be equal to or greater than the insensitive reference value is considered to be continuing and the period reaches a specified leakage determination period. reference value setting hand set and the determining leakage determination unit leaks to the gas supply passage has occurred, the metrics variable and is regulated in more insensitive reference value on the downstream side of Flowmeter having a gas leakage detection functions, characterized in that it comprises and. A flow rate detecting means for detecting a flow rate of the gas flowing through the gas supply path, and determining a magnitude of a predetermined measurement reference value and a dead reference value equal to or less than the measurement reference value and a gas flow rate detected by the flow rate detecting means; A flow rate determination unit, a flow rate integration unit that integrates a gas flow rate as a gas use flow rate during a period in which the gas flow rate is determined to be greater than or equal to a measurement reference value by the flow rate determination unit, and an integrated value integrated by the flow rate integration unit Output means for outputting as a used flow rate, and the flow rate detecting means when the period during which the flow rate of the gas is determined to be equal to or greater than the insensitive reference value is considered to be continuing and the period reaches a specified leakage determination period. Based on a leak determining means for determining that a leak has occurred in the gas supply path on the downstream side of the gas, and a gas flow rate fluctuation pattern detected by the flow rate detecting means. Obtains the estimated value of the minimum flow rate at consumers, including a gas leak detection function, characterized in that it comprises a reference value setting means for setting the metric value is regulated on the estimated value or less and more insensitive reference value Flowmeter. The said measurement reference value is set to below the minimum flow volume consumed by the gas consumption apparatus connected to the downstream of the said flow volume detection means in the said gas supply path, The Claim 1 or Claim 2 characterized by the above-mentioned. A flow meter with a gas leak detection function. 4. The use display unit according to claim 1, further comprising a usage display unit that indicates that the gas is passing during a period in which the gas flow rate is determined to be equal to or higher than the measurement reference value by the flow rate determination unit . A flow meter provided with the gas leakage detection function according to item 1 . 5. The flow rate having a gas leakage detection function according to claim 1, further comprising selection means capable of selecting an inspection mode in which the measurement reference value matches the dead reference value. Total.

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