JPH07151578A - Flow rate variation discriminating device - Google Patents

Abstract

PURPOSE:To discriminate whether a flow rate variation is generated by the ignition or the extinction of a gas utensil, or generated by the flow rate variation of the same gas utensil being used. CONSTITUTION:In a variation flow rate operation means 44, a variation flow rate is calculated from the variation of the present flow rate average value output from an average value operation means 42, and the variation of the past flow rate average value stored in a memory means 43. On the other hand, the dispersion value of an instant flow rate at every unit time is found by a dispersion operation means 45, and it is stored in the second memory means 46. By a discriminating means 47, it is discriminated whether the form made by the time transition of the dispersion stored in the second memory means 43 is a hanging bell form or a gently-sloping crest form, and also it is discriminated whether the variation flow is generated by an ignition or extension, generated by the flow rate variation of the same gas utensil itself.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate change discriminating apparatus for discriminating what kind of event causes a change in gas flow rate, and in particular whether the flow rate change is caused by ignition or extinction of a gas appliance. Or, it relates to a flow rate change determination device for determining whether or not the flow rate variation (proportional control) is caused by the same gas appliance being used.

[0002]

2. Description of the Related Art Recently, as a gas meter for home use, a meter equipped with a microcomputer and a safety function in addition to the function of measuring the flow rate of passing gas has been put into practical use. When the gas flow rate is detected or when the predetermined gas flow rate is detected for a predetermined time or longer, the gas cutoff valve is driven to cut off the gas flow path. These functions detect leaks in pipes and outflows of unnatural gas to prevent accidents and guarantee safety.

In this type of gas meter, the gas cutoff time is set on the basis of the maximum flow rate (maximum individual flow rate) of the individual flow rates of individual gas appliances (flow rates of individual gas appliances). If there is ignition or extinguishing of the gas appliance, the gas appliance and its individual flow rate are estimated and registered, and if this registration changes the maximum individual flow rate of the gas appliances currently in use, the gas cutoff time is reset. I have decided. Therefore, unless the gas appliances that have ignited or extinguished the fire and the individual flow rates are registered correctly, it is difficult to distinguish the dangerous gas usage state from the normal gas usage state, and the above-mentioned safety function operates effectively. do not do.

Conventionally, the ignition or extinction of a gas appliance has been detected as follows. That is, if the absolute value of the difference (changed flow rate) between the current flow rate and the flow rate at the immediately preceding flow rate unit time point is equal to or greater than the threshold value, there is always one independent change, that is, a new gas appliance is ignited and is not used. It is judged that the gas appliance that has started or is being used has been extinguished due to fire extinguishing, and the magnitude of the changed flow rate is compared with the magnitude of the individual flow rate value of each gas appliance, and the gas appliance with the flow rate change is determined. I'm estimating.

[0005]

As described above, in the conventional gas meter, the magnitude of the changed flow rate and the magnitude of the individual flow rate value of each gas appliance are compared to estimate the gas appliance having the flow rate change. Therefore, there were the following problems. That is, when, for example, a fan heater and a water heater are used as gas appliances and a flow rate change (decrease) equal to the flow rate used by the gas fan heater occurs due to proportional control of the water heater, the flow rate reduction by the water heater is reduced. May be erroneously determined to be due to being erased. If the gas appliance that causes the change in the flow rate is erroneously estimated in this manner, there is a problem that the above-described gas shutoff safety function does not work accurately.

The present invention has been made in view of the above problems, and an object thereof is, when there is a change in the flow rate, whether the change in the flow rate is caused by ignition or extinction of a gas appliance,
Another object of the present invention is to provide a flow rate change discriminating apparatus which can more accurately discriminate whether or not it is due to a flow rate fluctuation due to the same gas appliance being used, and can improve safety.

[0007]

According to a first aspect of the present invention, there is provided a flow rate change discriminating apparatus which stores a flow rate measuring means for measuring an instantaneous flow rate of gas and an instantaneous flow rate measured by the flow rate measuring means for each unit time. 1 storage means, and the respective output signals of the flow rate measuring means and the first storage means are input, and the current flow rate value measured by the flow rate measuring means and the first flow rate value.
Change flow rate calculating means for calculating a change flow rate using the past flow rate values stored in the storage means, and a dispersion calculating means for calculating a dispersion value of the instantaneous flow rate per unit time stored in the first storage means. And the second storage means for storing the dispersion value obtained by the dispersion calculation means, and the shape of the temporal change of the dispersion value stored in the second storage means, calculated by the change flow rate calculation means. And a determining means for determining what event caused the changed flow rate.

In this flow rate change discriminating device, the instantaneous flow rate of the gas is measured by the flow rate measuring means, and this instantaneous flow rate is stored in the first storage means every unit time. Then, the changed flow rate calculating means calculates the changed flow rate from the past flow rate value stored in the first storage means and the current flow rate value output from the flow rate measuring means. On the other hand, the variance calculation unit obtains the variance value of the instantaneous flow rate stored in the first storage unit for each unit time and stores it in the second storage unit. Then, by the determining means, what kind of event (ignition or fire extinguishing, or the same gas appliance) the change flow rate calculated by the change flow rate calculating means is based on the shape of the temporal change of the dispersion value stored in the second storage means. Flow rate fluctuation)
It is discriminated whether it is caused by.

According to a second aspect of the present invention, there is provided a flow rate change discriminating apparatus which comprises the discriminating means according to the first aspect, wherein when the shape of the temporal change of the dispersion value stored in the second storage means is a bell shape,
It is determined that the changed flow rate is caused by the ignition of a new gas appliance or the extinction of a gas appliance in use, and the shape of the temporal change of the dispersion value stored in the second storage means is gentle. When it is a mountain type, it is configured to judge that the changed flow rate is associated with the flow rate fluctuation of the same gas appliance in use.

According to a third aspect of the present invention, there is provided a flow rate change determination device according to the second aspect, wherein the flow rate change determination device further comprises a determination means, and when the total flow rate is increased, the flow rate change is caused by ignition of a new gas appliance. When the total flow rate is decreased, it is determined that the change in the flow rate is caused by the fire extinguishing of the gas appliance in use.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which a flow rate change determination device according to an embodiment of the present invention is applied to a gas meter. The gas meter 10 has a safety function using a microcomputer. Inside the gas meter 10, a gas flow path 11 having a gas inlet 16 and a gas outlet 17 is provided. Gas 20, such as city gas, flows into the gas passage 11 through a pipe (not shown),
The gas 20 is supplied to a gas appliance such as a gas stove (not shown). A gas shutoff valve 12 for shutting off the gas passage 11 and a gas flow meter 13 for measuring the flow rate of the gas passing through the gas passage 11 are sequentially arranged in the gas passage 11 from the gas inlet 16 side. It is set up.

A control unit 14 for controlling the gas cutoff valve 12 by inputting the output signal of the gas flow meter 13 is provided in the gas meter 10.

FIG. 2 is a block diagram showing the configuration of the control unit 14 and its peripherals in the gas meter 10 of this embodiment.
As shown in this figure, the control unit 14 includes a CPU (central processing unit) 30, a ROM (read only memory) 31,
A RAM (random access memory) 32, a clock 33 for measuring time, and an input / output port 34 are provided,
These are connected to each other by a bus 35. In addition to the gas flow meter 13 described above, a drive circuit 36 for driving the gas cutoff valve 12 is connected to the input / output port 34. In the control unit 14, the CPU 30 has the RAM 32.
As a working area, by executing the program stored in the ROM 31, it is possible to determine the event (ignition or fire extinguishing, or flow rate fluctuation of the same gas appliance) that causes the gas flow rate change, and to perform safety functions such as gas leak inspection. It has come to be realized.

FIG. 3 is a functional block diagram showing the function of the flow rate change discriminating apparatus of this embodiment. As shown in this figure, the flow rate change determination device averages the flow rate measuring means 41 for measuring the instantaneous flow rate of the gas and the instantaneous flow rate measured by this flow rate measuring means 41 at every predetermined time to obtain a flow rate average value. And an average value calculating means 42 for outputting
The first storage means 43 for storing the average value of the flow rate output from No. 2, the average value calculation means 42, and the first storage means 43.
Change flow rate calculation for calculating the change flow rate by inputting each of the output signals of 1) and using the current flow rate average value output from the average value calculation means 42 and the past flow rate average value stored in the first storage means 43. And means 44. The flow rate measuring unit 41 is the gas flow meter 13, the average value calculating unit 42 is the control unit 14, the first storage unit 43 is the RAM 32, and the change flow rate calculating unit 44.
Are respectively realized by the control unit 14.

In the present embodiment, the reason for calculating the average value by performing the step approximation by the average value calculating means 42 is as follows. That is, since the gas flow rate measured by the flow rate measuring means 41 always contains an error, it constantly fluctuates. Therefore, if this flow rate is directly used for the calculation of the change flow rate by the change flow rate calculation means 44, the accurate change flow rate cannot be calculated. Therefore, the calculation accuracy of the change flow rate is increased by calculating the flow rate average value for each predetermined time.

The flow rate change discriminating apparatus of this embodiment is further calculated by the dispersion calculation means 45 for calculating the dispersion value of the instantaneous flow rate stored in the first storage means 43 for each unit time, and this dispersion calculation means 45. What is the change flow rate calculated by the change flow rate calculating means 44 based on the shape of the second storage means 46 for storing the dispersion value and the time transition of the dispersion value stored in the second storage means 46. It is provided with a discriminating means 47 for discriminating whether it is caused by an event. The distributed calculation means 45 is the control unit 14, and the second storage means 46 is the RAM 3
2. The discriminating means 47 is realized by the control unit 14, respectively.

Specifically, the discriminating means 47 is adapted to make the following determination.

First, when the shape of the temporal change of the dispersion value stored in the second storage means 46 is a bell shape,
It is determined that the changed flow rate calculated by the changed flow rate calculation means 44 is caused by either the ignition of a new gas appliance or the extinction of a gas appliance in use. Here, it is assumed that when the total flow rate increases, a new gas appliance is ignited, and when the total flow rate decreases, the gas appliance in use is extinguished. On the other hand, the second storage means 46
When the shape of the dispersion value stored in the time course is a gentle mountain shape, the change flow rate calculated by the change flow rate calculating means 44 is the same gas appliance in use (for example, a water heater).
It is determined that this is caused by the flow rate fluctuation (proportional control).

The determination based on the shape of the variance value over time is based on the following consideration. That is, when the gas appliance is ignited or extinguished, the rise of the flow rate change is steep, and the flow rate change ends within a small number of flow rate units. Therefore, the shape of the temporal change of the dispersion value is a steep bell shape as shown in FIG. 5, for example. On the other hand, when the flow rate changes due to proportional control of a gas appliance such as a water heater, the flow rate changes gently over a plurality of flow rate units, and the shape of the temporal change of the dispersion value is, for example, as shown in FIG. Since it becomes a mold, it is determined by the difference in the shape of such a time transition. It should be noted that there is a similar difference when the transitions of the standard deviations are compared instead of the variance values, and therefore, in this specification, the “variance value” also includes the meaning of the standard deviation.

As a specific method for identifying the shape of the variance value with time, (1) a waveform pattern of the variance and time of the ignition and extinction values is obtained in advance, and this and the second pattern are obtained.
Of the actual variance value stored in the storage means 46, and a method of calculating and identifying the degree of conformance from the error amount, and (2) the variation value of the variance value. Thresholds (total amount from the time when there is no change in the variance value until it stops changing or when it changes to the opposite) and the time required to change the variance value (change duration time) A method of setting and identifying a value is conceivable.

Next, the discriminating operation of the flow rate change discriminating apparatus of the present embodiment will be concretely described with reference to the flow chart shown in FIG.

In this embodiment, the instantaneous flow rate of the gas 20 is measured by the flow rate measuring means 41, and the instantaneous flow rate is averaged (step approximation) by the average value calculating means 42 at every predetermined time and the average flow rate value is output. , This average flow rate is the first
Is stored in the storage means 43. Then, the change flow rate calculation means 44 calculates the change flow rate from the past flow rate average value stored in the first storage means 43 and the current flow rate average value output from the average value calculation means 42. On the other hand, the dispersion calculation means 45 obtains the dispersion value of the instantaneous flow rate stored in the first storage means 43 for each unit time, and this is the second value.
Is stored in the storage means 46. Then, as shown in FIG. 4, the determination unit 47 determines whether or not the temporal transition of the dispersion stored in the second storage unit 43 is bell-shaped (step S100). Here, when the shape of the temporal change of dispersion is not a bell shape but a gentle mountain shape (N), the change in flow rate is small, so the flow rate changes due to proportional control of the same gas appliance (for example, a water heater). It is determined that it is a thing (step S102). On the other hand, if the shape of the variance value over time is bell-shaped (Y), it is next determined whether or not the total flow rate is increasing (step S101), and if it is increasing (Y). First, it is determined that a new gas appliance is ignited (step S103). On the contrary, if the total flow rate is decreasing (N), it is determined that the gas appliance in use has been extinguished (step S10).
4).

When the gas meter 10 detects a gas flow rate of a predetermined amount or more, or when a predetermined gas flow rate is detected for a predetermined time or more, the gas shutoff valve 12 is driven to shut off the gas flow passage 11. Is the same as before,
The description is omitted.

FIG. 7 shows the flow rate sampling data (ignition, extinguishing waveform) for every 0.1 second, and for each sampling interval (0.1 second), the dispersion for 2 seconds before the sampling time is taken. It can be seen that the shapes of the time transitions of the dispersion value differences are different depending on the ignition and extinction waveforms and the flow rate fluctuations.

As described above, in the present embodiment, the distributed arithmetic means 4
The variance value of the instantaneous flow rate for each unit time is obtained by 5, and the change flow rate calculated by the change flow rate calculating means is calculated from the shape formed by the time transition, which event (ignition or extinguishing, or flow rate of the same gas appliance). It is possible to easily discriminate whether or not the change has occurred. Therefore, the accuracy of estimating the gas appliance and the individual flow rate is increased, and the safety of the gas meter 10 is improved.

[0027]

As described above, according to the flow rate change discriminating apparatus of the first to third aspects, the dispersion value of the instantaneous flow rate for each unit time is obtained, and from the shape of the time transition of the dispersion value,
Since it was determined what kind of event caused the changed flow rate, it is possible to easily determine whether the gas appliance is ignited or extinguished, or the flow rate fluctuation of the same gas appliance, and thus the gas appliance and individual The accuracy of estimating the flow rate is improved, and further, the safety function of the gas meter or the like can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a gas meter to which a flow rate change determination device according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a configuration of a control unit and its surroundings in FIG.

FIG. 3 is a block diagram showing a functional configuration of the flow rate change determination device of FIG.

FIG. 4 is a flowchart for explaining a determination operation in the flow rate change determination device of FIG.

FIG. 5 is a diagram showing a transition of an ignition (extinguishing) waveform of a gas appliance and a standard deviation of a flow rate.

FIG. 6 is a diagram showing a transition of a flow rate waveform and a standard deviation of the flow rate by proportional control of the same gas appliance.

FIG. 7 is a diagram showing a transition of a dispersion value of an ignition (fire extinguishing) waveform and a flow rate based on actual data.

[Explanation of symbols]

 10 gas meter 12 gas cutoff valve 13 gas flow meter (flow rate measuring means) 14 control unit

Claims (3)

[Claims] 1. A flow rate measuring means for measuring an instantaneous flow rate of gas, a first storage means for storing the instantaneous flow rate measured by the flow rate measuring means for each unit time, the flow rate measuring means and the first storage. Change flow rate calculating means for inputting each output signal of the means and calculating a change flow rate using the current flow rate value measured by the flow rate measuring means and the past flow rate value stored in the first storage means. A dispersion calculation unit for calculating a dispersion value of the instantaneous flow rate stored in the first storage unit for each unit time; a second storage unit for storing the dispersion value calculated by the dispersion calculation unit; And a discriminating means for discriminating what kind of event caused the change flow rate calculated by the change flow rate calculating means from the shape of the temporal change of the dispersion value stored in the storage means. Flow Change discrimination device. 2. When the shape of the temporal change of the dispersion value stored in the second storage means is a bell shape, the change means determines whether the change flow rate is a new gas appliance ignition or in use. When it is determined that the gas appliance is extinguished due to fire extinguishing, and the shape of the temporal change of the dispersion value stored in the second storage means is a gentle mountain shape, the change flow rate is the same gas appliance in use. The flow rate change determination device according to claim 1, wherein the flow rate change determination device determines that the flow rate change is associated with the flow rate variation. 3. The determining means determines that the flow rate change is caused by ignition of a new gas appliance when the total flow rate is increased, and when the total flow rate is decreased, the flow rate change is the gas in use. The flow rate change determination device according to claim 2, wherein the device determines that the flow rate change determination device is caused by extinguishing an appliance.