JPH1073247A - Gas flow monitoring method and gas meter implementing the same - Google Patents

Abstract

(57) [Summary] [Problem] To change G without changing the set safety continuous use time
This prevents erroneous shutoff of gas supply in a gas appliance having a large gas flow rate such as an HP. A safety continuous use time is set for each of a plurality of divided gas flow sections to allow continuous use, an increase or decrease in the gas flow is detected, and the use of the increased gas flow or the maximum of the remaining gas flows is determined. A gas flow monitoring method and a gas meter for monitoring whether or not use of a gas flow rate exceeds a safe continuous use time corresponding to the gas flow rate category, and shutting off a gas supply upon detecting the exceeding of the safety continuous use time. The gas meter has a step and a control unit that do not shut off the gas supply when the use of the gas flow rate corresponding to the predetermined gas flow rate section among the plurality of gas flow rate sections is detected. . Further, the gas meter has a rewritable memory storing a table including data indicating whether or not the gas is shut off in correspondence with the plurality of gas flow sections, and the control means controls the section corresponding to the increased gas flow rate in the table. Shut off or not shut off the gas supply when the safe continuous use time is exceeded according to the data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormal gas use state and shutting off the gas supply. The present invention relates to a gas flow rate monitoring method for a gas meter that shuts off supply of gas and a gas meter that implements the method.

[0002]

2. Description of the Related Art In general, a gas meter equipped with a microcomputer has a safety function of judging an abnormal state of a gas flow and shutting off the gas flow in order to prevent a gas accident. As one of the functions, there is a shut-off of safety continuous use time. This function is a function to judge that some abnormality has occurred and automatically shut off the gas when a certain gas flow rate is continuously used for a long time due to forgetting to turn off the gas appliance or some abnormal use. .

FIG. 7 is a chart and a graph showing the safe continuous use time for each of the gas flow rates. FIG. 7 (A) shows the time that can be used continuously for each section of the gas flow rate of the used gas appliance. FIG. 7B is a graph of the table of FIG. 7A, in which the vertical axis represents time and the horizontal axis represents gas consumption. As is clear from these, the relationship is set such that the safe continuous use time is longer when the flow rate is smaller, and becomes shorter as the flow rate is larger. In a conventional general gas appliance, it was possible to perform relatively sufficient safety management by using the safety continuous use time set in this manner.

[0004]

However, in recent years, gas appliances which are used for a long time at a large gas flow rate such as a gas engine heat pump (GHP) and a large-capacity gas water heater have been used normally. Even in such a state, the gas meter often determines that the gas appliance has been abnormally used due to long-time use and erroneously shuts off the gas. Such gas appliances are not widespread in all households, and the gas flow rates of these gas appliances vary, and the set values shown in FIG. It is not preferable in terms of safety to lengthen the use time uniformly.

Accordingly, an object of the present invention is to provide a method for preventing erroneous shutoff of gas supply in such a gas appliance without changing a set safety duration, and a gas meter for implementing the method. is there.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to set a safe continuous use time for allowing continuous use in each of a plurality of divided gas flow sections, detect an increase or decrease in gas flow rate, and increase the increased gas flow rate. Monitors whether the use of the flow rate or the use of the largest gas flow rate among the remaining gas flow rates exceeds the safe continuous use time corresponding to the category of the gas flow rate, and shuts off the gas supply when the excess is detected A method of monitoring a gas flow rate, comprising: when the use of a gas flow rate corresponding to a predetermined gas flow rate section among the plurality of gas flow rate sections is detected, not shutting off the gas supply. This is achieved by providing a flow monitoring method and a gas meter implementing the method.

[0007] Further, since the gas flow rate that requires the step of not interrupting is different depending on the gas flow rate of the gas appliance to be used, it is preferable that the gas flow rate section can be appropriately selected.

Further, the gas meter has a rewritable memory storing a table including data indicating the presence / absence of the shut-off corresponding to the plurality of gas flow rates. According to the data of the section corresponding to the maximum gas flow rate among the increased gas flow rates or the remaining gas flow rates, the gas supply is cut off or not cut off when the safe continuous use time is exceeded.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. However, the technical scope of the present invention is not limited to such an embodiment.

In this embodiment, a method for avoiding erroneous shutoff in continuous use will be described using a gas engine heat pump (hereinafter abbreviated as GHP) as an example. GHP is
A device that performs air conditioning for heating and cooling by rotating a compressor using a gas engine.Since fuel cost is lower than that of an electric heat pump, it is often used as a large-capacity air conditioner for schools and corporations. .
It is also widely used in ordinary households because of its low fuel cost.

Further, since the gas consumption of the GHP is large as described above, a charge lower than a normal charge may be applied. In such a case, the gas flow rate consumed by the GHP and the gas flow rate other than the normal charge may be applied. It is necessary to record both the gas flow consumed by the gas appliances. Therefore, when using GHP and other gas appliances, two gas meters are usually required.

FIG. 1 shows a method of connecting a gas meter to GHP and other gas appliances. In the case of FIG. 1 (A), the GHP 10 and a dedicated gas meter 14, and other gas appliances 12 and a general gas meter 15 are connected in parallel to a gas pipe 18. In this case, both the gas meters 14 and 15 have a gas shutoff control function and the like as described later. In the case of FIG.
A gas meter 16 dedicated to P10 and GHP, and other gas appliances 12 and a general gas meter 15 are connected in series to a gas pipe 18. In this case, since the general gas meter 15 and the gas meter 16 dedicated to GHP are on the common pipe 18, only the general gas meter 15 upstream of the pipe 18 needs to have the above-described gas shutoff control function and the like.

FIG. 2 is a schematic block diagram of a microcomputer 20 as control means provided on circuit boards in the gas meters 14 and 15. The microcomputer 20 controls various functions performed by the gas meters 14 and 15, and includes, for example, (1) a flow measurement function for integrating and storing a gas flow rate, and (2) a gas cutoff control function. Is mentioned. The gas shut-off control function monitors the change in gas flow rate, and when a predetermined total maximum gas flow value is exceeded, when an individual gas appliance exceeds an individual maximum gas flow rate, when a predetermined safe continuous use time is exceeded. In addition,
This function shuts off the gas shut-off valve when an earthquake with a seismic intensity above a certain level is detected.

In the microcomputer 20, for example, C
PU 201, RAM 202, ROM 203 in which control programs and other data are stored, timer 204 for measuring safe continuous use time, counter 205 for measuring total gas flow, counter 20 for measuring individual maximum flow
6 are connected via a bus 207. Also, an I / O unit 208 is connected as an interface.

The microcomputer 20 is supplied with a gas flow signal 209 from a gas flow meter (not shown) provided in the gas meter, and when a predetermined condition as described above is exceeded, a gas cutoff signal 210 is output. It is sent to the valve 19.

As described above, the gas meters 14 and 15
In addition to the function of measuring the gas flow rate and integrating and storing the gas flow rate, it monitors the change in the gas flow rate and shuts off the gas supply when it is determined that the gas flow rate is abnormal. FIG. 3 is a diagram for explaining the monitoring of the change in the gas flow rate. In the example of FIG. 3, a stove, a stove, a bath kettle, and a small water heater are used by a consumer. That is, this is an example in which the stove, the bath kettle, and the small water heater start driving one after another while the stove is driving, and end driving in the reverse order.

The gas meter detects the total gas flow per unit time every predetermined time, for example, 30 seconds, and stores the increase when the total gas flow changes, and keeps the increase until the increase decreases. The above-mentioned monitoring is performed by recognizing that the gas appliance corresponding to the amount is being driven. The monitoring contents are, as described above, whether or not the total gas flow rate is within the total maximum flow rate value, whether or not each increment is within the individual maximum flow rate value, and whether or not the safety continuous use time is exceeded. is there. In any case, when an abnormality is recognized, the microcomputer 20 generates a gas shutoff signal 210 so as to close the gas shutoff valve. These monitoring methods are described in detail in, for example, Japanese Patent Publication No. 61-59423, and will not be described in detail here.

FIG. 4 is a diagram for explaining a method of measuring the safe continuous use time. Referring to FIG. 4, a method of shutting off gas when the safe continuous use time is exceeded will be described. First,
7 is stored in the ROM 203 in the microcomputer 20.
The safe continuous use time corresponding to the gas flow rate category of the gas appliance as in (A) is stored. If the above-mentioned set safety continuous use time is exceeded without any fluctuation in the flow rate while the gas appliance is continuously used, it is determined that the gas appliance is abnormal due to forgetting to turn off the gas appliance, and the gas is shut off. When a plurality of gas appliances are used, monitoring is performed by focusing on the gas appliance having a large gas flow rate and a short time to shutoff. Also, when the total gas flow rate changes by a certain amount or more, the timer for measuring the safe continuous use time is cleared, and a new safe continuous use time is restarted. For example, when the use of the stove with the gas flow rate Q1 is started at time t1, an increase in the gas flow rate of Q1 is detected, the safe continuous use time T1 corresponding to the gas flow rate Q1 is applied, and the continuous use of Q1 is measured. A timer is started to monitor whether T1 has been exceeded. Further, when the water heater with the gas flow rate Q2 greater than Q1 is started at time t2, the safe continuous use time T
The timer of 1 is cleared, and the timer of the safe continuous use time T2 corresponding to the division of Q2 is newly started.

Next, in the case where a gas appliance having a relatively large gas flow rate and a long continuous use time such as GHP is used, when the use of the GHP is started at time t3, the conventional gas meter uses the hot water. The timer for the safe continuous use time of the vessel is cleared, and the measurement of the safe continuous use time T3 corresponding to the GHP gas flow rate Q3 starts. Then, if the use of the GHP exceeds the safe continuation use time T3 set in FIG. 7A even though the GHP is normally used, at time t4, the microcomputer determines that the GHP is abnormally used. The gas supply is shut off.

Therefore, in the embodiment of the present invention, when the use of the gas flow rate corresponding to the GHP is detected, the monitoring based on the safe continuous use time and the accompanying cut-off are not performed, so that the erroneous shut-off of the gas supply is avoided. I am trying to do it. FIG.
Is a safe continuous use time table (bypass table) for determining whether the detected gas flow rate falls into a predetermined gas flow rate category, and indicates that flag 1 is a predetermined gas flow rate category. I have. In the example of FIG.
2 is set as the GHP gas flow rate. FIG. 6 is a flowchart of the measurement of the safe continuous use time. This will be specifically described below with reference to the example of FIG. 4, the table of FIG. 5, and the flowchart of FIG.

First, in step S1, the gas flow rate Q0 at time t0 in FIG. 4 and the corresponding safe continuous use time T0 are set. At time t0, the gas appliance is not used and the gas flow rate is not detected.
The gas flow rate Q0 is 0, and the safe continuous use time T0 at this flow rate is not limited as shown in the section of FIG.
Step S2 is a step for measuring whether or not the safe continuous use time has elapsed by a timer. When the safe continuous use time has been reached, the gas supply is cut off in step S3.

Further, in step 4, the gas flow rate is measured, for example, every 30 seconds. When the stove having the gas flow rate Q1 starts to be used at time t1, a change in the gas flow rate is detected in step S5, and the measured gas flow rate is measured. Flow Q
1 and the gas flow rate Q0 are compared. If there is a certain amount of change, a change amount ΔQ is calculated in step S6. In this case, the variation .DELTA.Q is the gas flow rate Q1. Step S7 is a step for determining whether or not the change amount ΔQ falls under the gas flow rate category of the GHP.
Is 5000 kcal / h, for example, corresponds to Category 3 in FIG. 5 according to the table of FIG. 7A, and the flag of Category 3 is 0, which is not a GHP gas flow rate category. In this case, the process proceeds to the next step S8. I do. In step S8, Q1 and Q
0 are compared and Q1 is clearly greater than Q0, so Δ
The value of Q (Q1) is registered in step S9, and further registered as the maximum gas flow rate Qmax at that time. The safe continuous use time T0 is also the safe continuous use time T corresponding to Q1.
The timer monitoring is started with the changed safety continuation use time (step S11).

Next, when the use of the water heater at time t2 shown in FIG. 4 is started, a flow rate change is detected in the same manner as described above (step S5), and a change amount ΔQ is calculated (step S6). . The variation ΔQ in this case is Q2. further,
It is determined in step S7 whether or not the change amount ΔQ (Q2) is a category of the GHP gas flow rate. Assuming that Q2 is, for example, 10000 kcal / h, from FIG. 7 (A), Q2 corresponds to section 6 in the table of FIG.
Since it is not the gas flow rate category of P, the process also proceeds to the next step S8 in this case. In step S8, the change amount ΔQ is compared with Qmax. If ΔQ is smaller than Qmax,
The value of ΔQ is simply registered for use in step S10. In the case of FIG. 4, ΔQ (Q2) is Qma
x (Q1), ΔQ (Q2) is equal to step S
9 and is also registered as a new Qmax. The safe continuation use time T1 is also changed to the safe continuation use time T2 corresponding to the variation .DELTA.Q (Q2).

As described above, since the gas flow rate Q2 of the water heater in FIG. 4 is larger than the gas flow rate Q1 of the stove, in step S9, the gas flow rate Q2 of the water heater is registered as Qmax, and The time T1 is changed to the safe continuous use time T2 corresponding to the gas flow rate of the water heater, and the timer of the safety continuous use time which has been measured so far is cleared, and the timer is monitored at the changed safety continuous use time T2. Starts anew (step S1)
1).

Here, when the operation of the GHP is started at time t3, the gas flow rate further changes, and the change amount Δ
Q is calculated in step S6. Here, ΔQ is Q3 as shown in FIG. However, in step S7, the variation ΔQ is determined to be the GHP gas flow rate category 12 according to the table of FIG. As a result, ΔQ (Q3) is not registered as shown in FIG.
It does not go through 0 or 11. For this reason, the safe continuous use time T2 corresponding to the gas flow rate of the water heater is continuously measured.
Even if the safe continuous use time T3 corresponding to the gas flow rate of the GHP has elapsed (time t4), the safety continuous use time T2 corresponding to the gas amount of the water heater being measured has not elapsed. In this case, the gas supply is not shut off due to the continuous use of GHP at time t4. However, at time t5, the safe continuous use time T2 corresponding to the gas flow rate Q2 of the water heater is reached, so that the gas supply is shut off.

Conversely, when the use of these gas appliances is stopped, for example, when the use of the stove is stopped, the gas flow rate Q1 of the stove is calculated in step S6 as the gas flow decrease amount ΔQ. And the decrease amount Δ
Since Q (Q1) is smaller than the maximum gas flow rate Qmax (Q2), it is deleted in step S10. Further, for example, when the use of the water heater is stopped, the decrease amount ΔQ (Q2) is the maximum gas flow rate Qmax (Q2) up to that time.
Therefore, the gas flow rate Q1 of the stove, which is deleted in step S9 and is the largest ΔQ among the remaining ΔQs, is registered as the maximum gas flow rate Qmax.

When the use of the GHP is stopped, the steps S8, 9, 10, and 11 are bypassed in the step S7, as in the case of starting the use of the GHP described above.
The status quo is maintained.

Since not all gas consumers use the GHP, the large water heater, and the like, it is preferable that whether or not to make the determination in step S7 can be selected. Further, since the gas flow rate of such a gas appliance differs depending on the model, it is preferable that the setting of the gas flow rate category determined in step S7 can be changed at any time according to the situation. Therefore, by storing the table shown in FIG. 5 in the rewritable memory of the microcomputer, the gas flow rate section to be set can be selected. For example,
In FIG. 5, when the gas flow rate of the section 12 corresponding to the GHP gas flow rate is detected, it indicates that the supply of the gas is not shut off due to the lapse of the safe continuous use time of the gas flow rate. It is also possible to change the setting or to set a plurality of sections.

[0029]

As described above, according to the present invention, G
When a large flow rate is continuously used over a long period of time, such as in an HP or a large water heater, it is possible to prevent the supply of gas from being cut off erroneously due to the elapse of the set short safe continuous use time. Also, in the present invention, the safety continuation time is monitored for some gas flow sections in accordance with the flow rate of the gas appliance in question, rather than extending the safe continuation use time uniformly over all gas sections. Lack of security can minimize the decline in security levels.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for connecting a gas meter to a GHP and other gas appliances.

FIG. 2 is a schematic block diagram of a microcomputer in the gas meter.

FIG. 3 is a diagram for explaining monitoring of a change in gas flow rate.

FIG. 4 is a diagram for explaining a method of measuring a safe continuous use time.

FIG. 5 is a bypass table of safe continuous use time for each gas flow rate section.

FIG. 6 is a flowchart of measurement of a safe continuous use time.

FIG. 7 is a diagram showing a safe continuous use time for each gas flow rate section.

[Explanation of symbols]

 Reference Signs List 10 GHP 12 Gas appliances other than GHP 14 Gas meter 15 Gas meter 16 Gas meter 18 Gas piping 19 Gas shutoff valve 20 Microcomputer 204 Safety continuous use time timer 210 Gas shutoff signal

Claims (6)

[Claims] A safety continuous use time for allowing continuous use is set for each of a plurality of divided gas flow sections, an increase or decrease in the gas flow rate is detected, and the use of the increased gas flow rate or the remaining gas flow rate is determined. A gas flow monitoring method for monitoring whether or not the use of the maximum gas flow rate exceeds a safe continuous use time corresponding to the gas flow rate category, and shutting off a gas supply when detecting the exceeding; A method of monitoring a gas flow rate, comprising: when the use of a gas flow rate corresponding to a predetermined gas flow rate section among the sections is detected, not shutting off the gas supply. 2. A gas flow monitoring method according to claim 1, wherein said predetermined gas flow rate section can be selected as appropriate. 3. A safe continuous use time allowing continuous use is set for each of a plurality of divided gas flow sections, an increase or a decrease in the gas flow rate is detected, and the increased gas flow rate or the remaining gas flow rate is used. In the gas meter that monitors whether the use of the maximum gas flow rate exceeds the safe continuous use time corresponding to the gas flow rate section and shuts off the gas supply when detecting the exceeding, among the plurality of gas flow rate sections, A gas meter comprising a control unit that does not shut off the gas supply when the use of a gas flow rate corresponding to a predetermined gas flow rate category is detected. 4. A gas meter according to claim 3, wherein said predetermined gas flow rate section can be appropriately selected. 5. The gas meter according to claim 3, wherein the gas meter has a rewritable memory storing a table including data indicating whether or not the gas flow is interrupted in correspondence with the plurality of gas flow rates, and the control means. Performs the shutoff or non-interruption of the gas supply when the safe continuous use time is exceeded according to the data of the section corresponding to the maximum gas flow rate of the increased gas flow rate or the remaining gas flow rate in the table. I do. 6. The gas meter according to claim 3, wherein the gas meter is configured such that the continuous use of the maximum gas flow rate among the gas flow rates at which an increase is detected or the remaining gas flow rate corresponds to the gas flow rate. It is characterized in that whether or not the time is exceeded is monitored, and when the use of the gas flow rate corresponding to the predetermined gas flow rate category is detected, the safe continuous use time is not monitored.