JPH11118579A - Gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vortex flow rate type gas meter that can cope with a long-term use by reducing power consumption. SOLUTION: A drive control means 103 corresponds to the flow-rate region of a gas flow and drives a second gas flow-rate measuring means 102 from a low flow-rate region to an upper, specific flow-rate region, and stops the drive in the higher region. Also, a power supply control means 104 supplies power also to a first gas flow-rate measuring means 101 and the second gas flow-rate measuring means 102 while a gas flow rate is up to a specific flow- rate region exceeding the boundary between a high flow-rate region and a low flow-rate region and stops or suppresses power supply to the second gas flow-rate measuring means 102 when the gas flow rate exceeds the above specific flow-rate region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a gas meter.

[0002]

2. Description of the Related Art As a gas meter which has been widely and conventionally used, there is a gas meter of a membrane type. This membrane gas meter has a membrane inside the housing that repeats vibration by the pressure of the gas flow, and measures the flow rate of gas in response to the volume change due to the vibration of this membrane. This is a meter of the type which directly measures the volume of the gas by using. Due to its simple and practical structure and high durability, it has been widely used.

However, on the other hand, the conventional film type gas meter as described above has a characteristic that it is a mechanical type, and therefore, a microelectronic circuit such as a recent microcomputer (hereinafter abbreviated as a microcomputer) is used. There was an inconvenience that it was hard to be familiar with the digitization of gas meters.

Therefore, in addition to the gas meter of the type that directly measures the amount of gas mechanically, such as the above-mentioned membrane type gas meter, physical values of the gas flow such as the gas flow rate are measured and the measured values are measured. A so-called guess-type gas meter has been devised in which a numerical value of a gas flow rate is calculated by an arithmetic circuit such as a CPU of a microcomputer in response to the above.

That is, since the gas meter of the guessing type treats the numerical value of the gas flow rate as an electric signal from the measurement stage, the value of the gas flow rate can be transmitted, processed, and stored as a data signal after the measurement. Therefore, it has the characteristic of being very well adapted to a system for performing such data management and the like, and is attracting attention as a particularly suitable technique for a gas meter which has been digitized in recent years.

As a gas meter of such a guessing type,
An ultrasonic measurement method using the propagation time difference of ultrasonic waves, a turbine measurement method in which the number of rotations of a turbine due to a gas flow is counted by a device such as a rotary encoder, and a value of a gas flow rate is calculated based thereon, which is generated by the gas flow. A differential pressure measurement method using a pressure difference between two points, or a vortex generator (such as a vortex generator arranged in an inverted triangle with respect to the flow) provided in a conduction path, with vortices in the gas flow By generating turbulence, fluid velocity is measured by using the fluid vibration phenomenon caused by the Coanda effect of the gas flow at that time. The gas flow rate is measured based on the occurrence of a fluidic type or Karman vortex street Several methods have been proposed, such as the vortex method such as the Karman vortex method, all of which have attracted attention because they can accurately measure the gas flow rate with continuous values. To have.

[0007] Among the gas meter technologies broadly classified as so-called inferential gas meters as described above, the vortex gas meter in particular has a frequency characteristic proportional to the gas flow rate (that is, good linearity of measurement). The structure is simple and there is no need for mechanical moving parts, so there is no need to worry about mechanical failure.Also, the volume flow rate can be measured stably because it is hardly affected by the composition, density, temperature, etc. of the fluid. And the fact that the pressure loss is so small that it hardly adversely affects the originally used gas flow rate. Technological utility has come into the spotlight, and further technical refinement and the like have been demanded, and research and development thereof have been actively demanded.

However, in a swirl type gas meter expected to have such high usefulness, a dead zone generally exists in a small flow rate region, and the Reynolds number of the gas flow decreases as the gas flow rate decreases. As a result, it is difficult to generate a vortex, so that a gas flow having a small flow rate of a certain level or less (for example, a flow rate range of 150 l / h or less) cannot be measured substantially.

Therefore, in such a vortex flow type gas meter, in order to supplement the measurement of the gas flow rate in a small flow rate region where the measurement by the vortex flow meter cannot be performed, the gas flow rate in the small flow rate region is reduced. A technique has been devised in which a second flow rate measuring means, such as a mass flow meter using a heating element and a temperature sensor, capable of measurement is used in combination with the above-mentioned vortex flow meter. It is disclosed by Japanese Patent No.

[0010]

However, in recent years, as described above, it has been strongly demanded to incorporate a microcomputer in the gas meter, so that the power for driving the microcomputer and the various flow sensors described above is supplied. It must be kept stable for many years. For this reason, the battery built into the gas meter needs to be used without replacing the built-in battery over such many years, since the gas meter is sealed as a measuring instrument once it is installed. is there.

Moreover, in recent years, it has been required to further extend the service life of the gas meter from 7 years to 10 years, so that the built-in battery can be kept usable for a long time. It is becoming necessary. In addition, on the other hand, as the gas meter has become multifunctional, a battery as a power source for supplying the above-mentioned electric power for many years is required to have a larger capacity. Since there is also a demand for miniaturization as a whole, it is difficult to increase the size of a battery built therein.

[0012] Therefore, by using the battery built in the gas meter as described above without replacing it for many years,
In order to supply power stably, it is essential to reduce the amount of power consumed by the gas meter.
However, in a conventional gas meter that combines two types of flow meters, such as the above-described vortex flow meter and a flow meter such as a mass flow meter of another type, using such two flow meters The power consumption is increased due to the presence of the power supply, which is contrary to the power saving. Moreover, the necessity of the two types of flow rate measuring means is inevitable in the theory of operation of a gas meter of the vortex flow type, and therefore these two flow meters must be used.

In addition, a mass flow meter using a heating element and a temperature sensor is employed as the second flow rate measuring means in order to take advantage of the feature that a mass flow rate can be measured instead of a volume flow rate. It is considered preferable, but when such a mass flow meter is adopted,
By measuring the mass flow rate even in the small flow rate range, accurate flow rate measurement can be performed with almost no influence on conditions such as gas pressure and temperature, while generally converting electric power to heat energy. However, since the conversion efficiency is low, a large amount of power consumption is required. Therefore, there is a problem that the power consumption is particularly large because a heating element that converts such power into heat is used.

As described above, the conventional vortex flow rate gas meter has a problem that it is difficult to save power. The present invention has been made in order to solve such a problem, and in a vortex flow rate gas meter having various features, which is a technique particularly suitable as an inferential gas meter, it is possible to reduce power consumption. It is an object of the present invention to provide a vortex flow rate gas meter which can be realized and sufficiently used for many years.

[0015]

First, a gas meter according to the present invention generates a vortex in a gas flow, and the flow rate of the gas flow in a high flow rate region corresponding to the state of flow change caused by the vortex. Vortex flow rate measuring first gas flow rate measuring means, and second gas flow rate measuring means for measuring the flow rate of the gas flow in a low flow rate range lower than the flow rate in a high flow rate range. do it,
In the gas meter that measures the flow rate of the gas flow in the high flow rate range and the low flow rate range, the second gas flow rate measuring unit is configured to set the second gas flow rate measurement unit to a predetermined specific flow rate or less corresponding to the flow rate range of the gas flow. It is characterized by comprising a drive control means for driving up to the flow rate range and stopping the drive in the flow rate range exceeding the specific flow rate range. In addition, it goes without saying that the driving and stopping of the first gas flow rate measuring means may be controlled at the same time.

That is, in the conventional gas meter, both the first and second gas flow rate measuring means are always used in a driving state, so that two systems of power consumption for driving both of them are required. For this reason, it has conventionally been difficult to reduce power consumption. However, according to the present invention, when the measurement can be performed by the first gas flow rate measuring means of the vortex flow rate method, the first gas flow rate measuring means is driven to perform the measurement, while the first gas flow rate measuring means does not need to be driven. The driving of the second gas flow rate measuring means is stopped. Conversely, when measurement by the second gas flow rate measuring means is possible,
The first gas flow rate measuring means which does not need to be driven may be stopped while the gas flow rate measuring means is driven. As a result, the power consumption required for useless driving can be saved, and the power consumption can be reduced.

Second, the gas meter according to the present invention has the first
In the gas meter described above, while the first gas flow rate measuring means is being driven and the second gas flow rate measuring means is being stopped, power supply to the second gas flow rate measuring means is stopped or The gas meter further includes a power supply control unit for suppressing the power supply.

That is, in addition to the technique described in the first aspect, it is unnecessary to supply electric power to the other gas flow rate measuring means while one of them is being driven. By doing so, power consumption can be further reduced, which is desirable. Therefore, the power supply control means controls the stop of the power supply in such a manner.

Third, the gas meter according to the present invention has the first
In the gas meter according to the present invention, the first gas flow rate measuring means is also provided with the second gas flow rate measuring means until the gas flow rate reaches a specific flow rate area above a boundary between the high flow rate area and the low flow rate area. Power supply control means for stopping or suppressing power supply to the second gas flow rate measurement means when the gas flow rate exceeds the specific flow rate range.
It is a gas meter further provided.

That is, even if the flow rate fluctuates frequently at the boundary between the high flow rate area and the low flow rate area, that is, the flow rate area near the switching point between the first gas flow rate measurement means area and the second gas flow rate measurement means. In addition, since it is not necessary to switch the drive between the first gas flow measuring means and the second gas flow measuring means abruptly, the reliability of the measurement is improved. For example, when a mass flow meter is employed as the second gas flow rate measuring means, if there is a frequent switching operation in the boundary region as described above, a time lag until the heating element reaches a sufficient heat generation amount, etc. As a result, it may not be possible to sufficiently follow the frequent switching timing, and it may be impossible to accurately measure the gas flow rate depending on conditions such as the accuracy of the gas flow rate measuring means and the use environment. Therefore, according to the technology described in the third aspect, in the flow rate region near the switching point, both the first gas flow rate measuring means and the second gas flow rate measuring means are supplied with at least only electric power, or furthermore, By driving such that the amount of power is controlled to the minimum required amount, for example, the heating element can be heated with a minimum amount of power that does not cause a loss of the effective power amount, or the two measuring means can be used. Thus, the gas flow rate can be measured at the same time, so that the responsiveness to the frequent switching operation in the boundary region as described above is optimized, and more reliable gas flow rate measurement can be performed.

Fourth, a gas meter according to the present invention is a first type of vortex flow system in which a vortex is generated in a gas flow and the flow rate of the gas flow in a high flow rate region is measured in accordance with the state of the vortex. A gas flow rate measuring means, and a second gas flow rate measuring means for measuring a flow rate in a low flow rate range that is lower than a flow rate in the high flow rate range of the gas flow, wherein the high flow rate of the gas flow A gas meter for measuring the flow rate of the first gas flow rate measuring means and the second gas flow rate measuring means in a gas meter for measuring the flow rate in the low flow rate range.
A driving control means for stopping the driving of the second gas flow measuring means during the driving period of the gas flow measuring means is provided.

That is, in the gas meters described in the first to third aspects, the driving of the first and second gas flow rate measuring means is selectively performed by dividing the driving of the first and second gas flow rate means into high and low ranges of the flow rate of the gas flow. In the gas meter according to the fourth aspect, the driving of the first and second gas flow rate measuring means is time-division driving, and the first gas flow rate measuring means is provided for each driving time. During the drive period, the drive control means controls the second gas flow rate measurement means to stop driving. As a result, similarly to the technique described in the first aspect, it is possible to reduce the power consumption required for useless driving and realize power saving of the power consumption.

In the gas meter according to the fourth aspect, the power supply to the second gas flow rate measuring means may be stopped or suppressed while the first gas flow rate measuring means is being driven. A gas meter further comprising a control unit.

That is, by stopping the power supply to the gas flow rate measuring means while the driving is stopped, the power consumption can be further reduced as in the technique described in the second aspect. Sixthly, in the gas meter according to the present invention, in the gas meter according to any one of the first to fifth aspects, the second gas flow rate measuring means includes a heating element disposed upstream of the gas flow and the gas flow rate measuring means. And a temperature sensor disposed on the downstream side of the gas flow rate measuring device.

That is, from the advantage that accurate measurement can be performed particularly in a low flow rate region, it is preferable to employ a gas flow rate measuring means of a mass flow type as the second gas flow rate measuring means according to the present invention. Furthermore, when such a mass flow rate method is adopted, it is desirable to reduce the power consumption required for the heating element and the like as much as possible. It can be said that the technology of the present invention can be used particularly optimally.

The vortex flow meter system is particularly suitable as the first gas flow measuring means. This is because the vortex flow meter method generally has a frequency characteristic proportional to the gas flow rate (that is, has good linearity of measurement), and has a simple structure, does not require a mechanically movable part, and has a concern about mechanical failure. And there is almost no influence on the composition, density, temperature, etc. of the fluid, so that it is possible to measure the volume flow rate stably. This is because it has features such as the absence of a gas meter, and is familiar with the tendency of gas meters to be controlled by microcomputers. As such a vortex flow meter type, here, a Karman vortex type that generates a Karman vortex and measures its frequency and the like, a swirl type that generates a swirl in a gas flow and measures its rotational motion, Alternatively, a fluid vane or the like, in which a gas flow is circulated by a Coanda effect using a guide vane or the like and a vibration generated at that time is measured, can be applied.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the gas meter according to the present invention will be described below in detail with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram showing a schematic configuration of a main part of a gas meter according to the present invention. FIG. 2 shows, in particular, the gas meter according to the first embodiment.
It is a figure which shows the outline | summary of a more detailed circuit structure centering on 2nd gas flow rate measuring means. In the gas meter according to the present invention, in particular, the drive control means and the power supply control means of the second gas flow rate measurement means are characteristic parts as their technical main parts, so that the description is simplified. In the following description, a description will be given mainly of such a characteristic portion of the present invention.

The gas meter according to the first embodiment generates a vortex in a gas flow and measures a flow rate of the gas flow in a high flow rate region in accordance with a state of change of the gas flow due to the vortex. A first gas flow rate measuring means 101, and a second gas flow rate measuring means 102 for measuring a flow rate in a low flow rate range that is lower than a flow rate of the gas flow in a high flow rate range, A gas meter for measuring the flow rate of the gas flow in the high flow rate region and the low flow rate region, wherein the driving / driving of the second gas flow rate measuring means 102 corresponds to the flow rate range of the gas flow.
The second gas flow rate measuring means 102 is driven to control the stop, that is, from a low flow rate range including 0 l / h to an upper specific flow rate range (150 l / h in the present embodiment), and Drive control means 10 for stopping the drive in the region
3 and a specific flow rate range where the gas flow rate is equal to or higher than the boundary between the high flow rate range and the low flow rate range (in this embodiment, 150 l /
Until h), power is supplied to both the first gas flow rate measuring means 101 and the second gas flow rate measuring means 102, and when the gas flow rate exceeds the specific flow rate range, the second gas flow rate And a power supply control means 104 for stopping or suppressing the power supply to the gas flow rate measuring means 102.
Needless to say, the battery 106 is connected to the power supply control means 104 as a power supply for supplying driving power. In addition, the gas meter also includes a gas flow integrating circuit system for performing the function of the original gas meter, that is, the function of an instrument for integrating the gas flow value, a display means such as a liquid crystal panel for displaying the circuit, or a counter mechanism. Needless to say, the components related to the gas flow rate integrating function as a conventional ordinary gas meter may be the same as those in the related art, and therefore detailed description and illustration thereof are omitted. I do.

As the first gas flow rate measuring means 101 of the vortex flow rate method, a Karman vortex method for generating a Karman vortex and measuring its frequency or the like, or a swirl generated in a gas flow to measure its rotational movement. A swirl type or a fluid type in which a gas flow is circulated by a Coanda effect using a guide vane or the like and vibration generated at that time is measured can be applied. As for the more detailed structure and the like of the first gas flow rate measuring means 101, a conventional technique may be applied to the first gas flow rate measuring means 101 itself, and therefore, detailed description thereof is omitted in the present specification for simplification of description. .

The second gas flow rate measuring means 1
Reference numeral 02 denotes a mass flow rate gas flow measuring unit 102 including a temperature sensor disposed on the upstream side and a downstream side of the gas flow, and a heating element disposed therebetween. In the gas meter of the first embodiment in which the main part is configured as described above, in particular, the second gas flow rate measuring means 102
Further, the drive control means 103 for controlling the drive is configured in more detail as shown in FIG.

That is, the second gas flow rate measuring means 102 which is a mass flow meter is provided with an upstream temperature sensor 202 for measuring the temperature on the upstream side of the heater 201 and a downstream temperature sensor for measuring the temperature on the downstream side. 203 is provided. Further, the drive control means 103 is connected to the upstream temperature sensor 20.
Amplifier 302 for amplifying the signal detected in step 2 and sending it to the switching circuit 301, and amplifier 303 for amplifying the signal detected by the downstream temperature sensor 203 and sending it to the switching circuit 301.
A switching circuit 301 for switching a period for monitoring the signal of the upstream temperature sensor 202 and a period for monitoring the signal of the downstream temperature sensor 203 based on, for example, a clock signal (not shown), and a heater driving circuit 304 for driving the heater 201. And the first gas flow rate measuring means 10
The gas flow rate measured at 1 and the second gas flow rate measuring means 10
And a drive selection circuit 305 for selecting which of them to drive based on the gas flow rate measured in step 2.

The drive selection circuit 305 selects the second gas flow rate measuring means 102 based on the measured gas flow rate and selects the second gas flow rate measuring means 102 if the gas flow rate is a low flow rate range below a specific flow range. I do. If the gas flow rate is a high flow rate range exceeding a specific flow rate range, the first gas flow rate measuring means 1
01 is selected and driven.

When the drive selection circuit 305 determines whether the flow rate range is high or low, the power supply control means 104 also determines the second gas if the gas flow rate is in the low flow rate range. Power is supplied to the flow rate measuring means 102, and power is supplied to the first gas flow rate measuring means 102 in a high flow rate range. It should be noted, however, that the first gas flow rate measuring unit 101 can measure the flow rate from the flow rate range at the boundary between the high flow rate range where accurate measurement is possible and the low flow rate range where it is difficult, to a specific high flow rate further upward. In the flow rate range, power is supplied to both the first gas flow rate measuring means 101 and the second gas flow rate measuring means 102.

The power supply control means 104 supplies power to a circuit system such as the drive control means 103, and the power consumption of the circuit system is compared with the gas flow rate measurement means 101 and 102. Power is always sent to these circuit systems in order to give priority to performing reliable operation and measurement control.

The drive selection circuit 305 is, for example, as shown in FIG.
As shown schematically in the flow rate region, when the lower limit value of the high flow rate region where accurate measurement by the first gas flow rate measuring means 101 is 100 l / h, the lower limit value It may be a point that is a boundary of switching between the first gas flow rate measuring means 101 and the second gas flow rate measuring means 102, but rather than switching the measurement operation at one point of the above-described boundary, for example, As shown in FIG. 3, the range in which the second gas flow rate measuring means 102 can be driven is set to 0.
starting at 1 / h and above 1 at 100 l / h
By setting the range in which the first gas flow rate measuring means 101 can be driven to a range between the lower limit value of 100 l / h and 6000 l / h on the other hand, while setting the range up to 50 l / h, as a result, 100 to 150 l / h as the boundary area
The first gas flow rate measuring means 101
And the second gas flow rate measuring means 102 is supplied with electric power, and both are driven. The flow rate range in which both are driven simultaneously is such a flow rate range (100 to 150).
1 / h), there is practically no adverse effect in terms of power loss.

For example, in the example shown in FIG. 3, the overlap of the flow rate regions where both are driven at the same time is at most 50 l / h between 100 l / h and 150 l / h. Compared with ~ 6000 l / h,
This is because the area is less than 1%. By providing a flow area in which the driving of both of the measuring means overlaps in the boundary area, more accurate and reliable gas flow measurement can be performed. That is, since such a great advantage of improvement in reliability is obtained, an overlap flow rate region for simultaneously driving both the first and second measuring means is provided.

By the way, the drive selection circuit 305 is
In the present embodiment, the drive / stop of the second gas flow rate measuring means 102 is selected as shown in FIG. 3, which is described in more detail by the first gas flow rate measuring means 101 and the second gas flow rate Based on the signal detected and transmitted by the measuring means 102, a value in the range of 0 to 150 l / h is a second gas suitable for measurement in such a lower region (low flow rate region). The value measured by the flow rate measuring means 102 is adopted.

On the other hand, the first gas flow rate measuring means 101
Since accurate measurement is difficult in a flow rate range of 00 l / h or less, measurement can be performed only in a flow rate range higher than that. Therefore, the measurement value of the first gas flow measurement unit 101 is adopted as the measurement value in the high flow rate range above 150 l / h. The first gas flow rate measuring means 1
As for 01, in order to provide a range in which the driving of both measuring means in the boundary region of the flow rate overlaps as described above,
In this embodiment, the drive is always performed.

However, in order to more strictly reduce the power consumption, it is strictly useless to drive the first gas flow rate measuring means 101 when the lower limit value of the measurement is 100 l / h or less, for example. , Such gas flow rate 100 l / h
It goes without saying that the driving of the first gas flow rate measuring means 101 may be stopped in the following regions. However, in order to simplify the circuit system, in the present embodiment, the functions of the first gas flow rate measuring unit 101 for stopping driving and stopping power supply are omitted.

The switching circuit 301 and the drive selection circuit 305 of the drive control circuit 103 are constituted by a CPU (not shown) such as a microcomputer built in a gas meter, which has been widely used in recent years, and its peripheral circuit system. May be used to construct. Alternatively, it is needless to say that a discrete circuit element or the like may be combined.

Next, the drive control and the operation of the second gas flow rate measuring means 102 in the gas meter of the first embodiment having the main components as described above will be described with reference to the schematic flowchart shown in FIG. State. The first gas flow rate measuring means 101 is, for example, a clock circuit (not shown).
A signal corresponding to the gas flow rate is detected for each specific sampling time based on the timing pulse generated from the above (s1). This detection may be performed according to the function of the conventional vortex flowmeter and its driving method. Then, the detected signal is transmitted to the drive selection circuit 305 (s
2).

Subsequently, the drive selection circuit 305 determines whether or not the transmitted signal is a signal corresponding to a measured value in a high flow rate range above 150 l / h (s).
3). At this time, if it is determined that the signal is a signal corresponding to the measured value in the high flow rate range above 150 l / h (Y in s3), the first gas flow rate measuring means 101
Is adopted (s4). At this time, even if the second gas flow rate measuring means 102 is already being driven, the measured value is not adopted.

Then, the driving of the second gas flow rate measuring means 102 is stopped (s5), and the power supply thereto is also stopped (s6). On the other hand, in s3 (step 3), 1
If it is determined that the signal is a signal corresponding to a measured value in a low flow rate range of 50 l / h or less (N in s3), 10
In the range of 0 to 150 l / h, the measurement can still be performed by the first gas flow rate measuring means 101, but the second gas flow rate measuring means 102 can perform more accurate measurement in such a low flow rate range. In order to use the measured value, the driving of the second gas flow rate measuring means 102 is started. Alternatively, if the driving of the second gas flow rate measuring means 102 has already been continued, it is further continued (s7). Also, at this time, it goes without saying that driving the second gas flow rate measuring means 102 necessarily supplies power thereto (not shown). On the other hand, as described above, the first gas flow measuring means 101 is continuously driven.

In this way, the second gas flow rate measuring means 102 is driven, and the value measured by the second gas flow rate measuring means 102 is adopted (s8). However, at this time, the measurement value of the first gas flow rate measuring means 101 is
Although monitoring is performed to execute the selection operation as described above with reference to 05, it goes without saying that it is not adopted as data for calculating a gas flow rate value as a gas meter.

In this way, it is determined whether or not the gas flow rate is in the low flow rate range. The measurement in the low flow rate range is performed by driving the second gas flow rate measuring means 102, and the measurement is performed in the high flow rate range. Is measured by driving the first gas flow rate measuring means 101 while the second gas flow rate measuring means 10
2 is stopped and the power supply is also stopped, so that the power consumption can be reduced. Actually, an experiment was conducted in which the gas meter of the first embodiment as described above was continuously used for a long period of time under the same conditions as in actual use, and the power consumption was confirmed. It was confirmed that the power consumption was about half that of a gas meter that measures a high / low flow rate region using a measuring unit. That is, in other words, it was confirmed that even if the same battery as that of the related art was used, the battery could be continuously used without replacing the battery for twice as long as that of the related art.

In the first embodiment, the flow rate range (boundary area) for driving (overlapping) both the first gas flow rate measuring means 101 and the second gas flow rate measuring means 102 is 100 l. / H to 150 l / h, the value of this boundary region is not limited to the value of the capacity of the gas meter used as the gas flow meter or the measurable range of the first gas flow measuring means 101. Since there may be different optimal values for each type of gas meter depending on various individual conditions such as the lower limit value,
It goes without saying that it is only necessary to set such a condition as to meet the conditions of each gas meter as much as possible.

Further, there is no flow area (boundary area) that is driven to overlap as described above. For example, one point of 100 l / h, which is the lower limit of the measurable range of the first gas flow measuring means 101, is provided. Needless to say, the drive may be switched by using. (Embodiment 2) In the first embodiment, the control of the driving / stopping of the second gas flow rate measuring means 102 and the control of the supply / stop of electric power based on the height / low of the gas flow rate range is performed. However, in addition, the first gas flow rate measuring means 101 and the second gas flow rate measuring means 102 may be driven in a time-division manner. FIG. 5 shows an outline of the configuration of the gas meter according to the second embodiment of the present invention when such time-division driving is employed. In the case of the gas meter driven in a time-sharing manner as described above, one of the first gas flow rate measuring means 101 and the second gas flow rate measuring means 102 is off-duty while one is on-duty. Therefore, by supplying no power to the second measuring means 102 in the off-duty state and not driving it, the second gas flow rate measuring means 102 at least for the off-duty period can be used. The power consumption of the drive control unit 103, for example, in the heater drive circuit 304 can be reduced.

That is, as shown in FIG. 5, the gas meter of the second embodiment is the same as the gas meter of the first embodiment shown in FIG. It can be said that the most characteristic point in the configuration is that the divided drive circuit 501 is used instead of the drive selection circuit 305. This time-division driving circuit 501 includes:
For example, based on a timing pulse generated from a clock circuit (not shown) or the like, the first gas flow rate measuring means 101 and the second gas flow rate measuring means 102 are alternately intermittently separated by a specific off-duty period. Drive each.

The power supply control means 104 supplies power to the measuring means in the on-duty periods 601 and 602 selected by the time-division driving circuit 501, and supplies the off-duty period 603 The supply of electric power to the measuring unit 604 is stopped particularly for the second gas flow measuring unit 102. That is, the power supply is stopped at least during the off-duty period 603. FIG. 6 schematically shows a preferred example of such a timing. At this time, the first gas flow rate measuring means 1
Since the power supply (that is, the supply of the power supply voltage) is switched between on and off each time the on / off of the duty is switched on and off, the 01 and the second gas flow rate measuring means 102 operate at the time of restarting the power supply. Although a rise time is required, there is a high possibility that a measurement error will increase during such a time lag period for the rise, so in order to ensure the reliability of the measurement operation of each of the measurement means 101 and 102, The control may be performed so that the gas flow value is not measured during the rising period. That is, the dead time in which the rising period is not measured is a common off-duty period 605, 605 'for both measuring means 101, 102.
It should just be appropriated. In particular, the second gas flow measuring means 1
It is desirable to apply the dead time during which the above-described measurement is not performed to the off-duty period 605 having a portion that overlaps the rising period of 02.

As for the gas meter of the second embodiment, an experiment was conducted in the same manner as in the first embodiment, and as a result, it was confirmed that the power consumption was の that of the conventional gas meter.

[0051]

As described above in detail, according to the present invention, in a vortex flow rate gas meter having various features, which is a technique particularly preferable as a guess type gas meter, the power consumption of the gas meter is reduced. It is possible to provide a gas meter of a vortex flow rate type which realizes power saving and can sufficiently cope with use for many years.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a main part of a gas meter according to the present invention.

FIG. 2 is a diagram showing an outline of a configuration centering on a second gas flow rate measuring means in the gas meter according to the first embodiment.

FIG. 3 is a diagram schematically showing both high / low flow areas and driving coverage areas of a first gas flow measuring means 101 and a second gas flow measuring means 102;

FIG. 4 is a schematic flowchart showing drive control and operation of a second gas flow rate measuring means 102;

FIG. 5 is a diagram illustrating an outline of a configuration of a gas meter according to a second embodiment.

FIG. 6 is a diagram schematically illustrating an example of time-division driving timing of each of the measuring units 101 and 102 in the gas meter according to the second embodiment.

[Explanation of symbols]

 101: first gas flow rate measuring means 102: second gas flow rate measuring means 103: drive control means 104: power supply control means

Claims (6)

[Claims] 1. A vortex flowmeter type first gas flow measurement method for generating a vortex in a gas flow and measuring a flow rate of the gas flow in a high flow rate region in accordance with a state of flow change caused by the vortex. Means, and a second gas flow rate measuring means for measuring a flow rate in a low flow rate area which is a lower flow rate than the flow rate in the high flow rate area, wherein the high flow rate area and the low flow rate area of the gas flow In the gas meter that measures the flow rate of the gas flow, the second gas flow rate measurement unit is driven up to a flow rate range equal to or less than a predetermined specific flow rate, corresponding to the flow rate range of the gas flow, and the specific flow rate range is changed. When the flow rate exceeds the
And a drive control means for stopping the drive of the gas flow measurement means. 2. The gas meter according to claim 1, wherein said first gas flow rate measuring means is being driven, and said second gas flow rate measuring means is being driven.
While the driving of the gas flow rate measuring means is stopped, the second
A power supply control means for stopping or suppressing power supply to the gas flow rate measurement means. 3. The gas meter according to claim 1, wherein the gas flow rate in the flow rate range from a boundary between the high flow rate range and the low flow rate range to a specific higher flow rate range. Power is supplied to both the gas flow rate measuring means and the second gas flow rate measuring means, and when the gas flow rate exceeds the specific flow rate range, the power supply to the second gas flow rate measuring means is stopped or suppressed. A gas meter further comprising power supply control means. 4. A vortex flow meter type first gas flow measurement method for generating a vortex in a gas flow and measuring a flow rate of the gas flow in a high flow rate region in accordance with a state of flow change caused by the vortex. Means, and a second gas flow rate measuring means for measuring a flow rate in a low flow rate range that is lower than a flow rate in the high flow rate range of the gas flow, the high flow rate range of the gas flow and the A gas meter for measuring a flow rate in a low flow rate region, wherein the first gas flow rate measuring means and the second gas flow rate measuring means are time-divisionally driven drive control means, wherein the first gas flow rate measuring means A driving control unit for stopping the driving of the second gas flow rate measuring unit during the driving period. 5. The gas meter according to claim 4, wherein the power supply control unit stops or suppresses the power supply to the second gas flow rate measurement unit during the non-driving period of the second gas flow rate measurement unit. , Further comprising a gas meter. 6. The gas meter according to any one of claims 1 to 5, wherein the second gas flow rate measuring means is disposed on a heating element arranged on an upstream side of the gas flow and on a downstream side of the gas flow. A gas flow rate measuring means of a mass flow rate type provided with a temperature sensor.