JP2008164536A - Gas circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dissolve a problem of maintenance, by surely preventing a single unit of gas appliance from being used over the utilization upper-limit time. <P>SOLUTION: A gas circuit breaker, for shutting off the feed of a gas when the use time of the gas appliance reaches the use upper limit time TU, includes: a gas flow rate detection means 1 for detecting the average gas flow rate Qa; a flow rate section discrimination means 2 for discriminating a flow rate section of the average gas flow rate; a time measurement means 3 for measuring a continuous time belonging to the same flow rate section by continuing the average gas flow rate; a gas shut-off means 6 for shutting off the gas feed, when the continuous time reaches the utilization upper limit time; and an upper-limit time modification means 5 for regarding a time bound by subtracting the continuous time belonging to a prior time flow rate section, from the use upper limit time of this time flow rate section, as the utilization upper limit time, when the flow rate section belonging to this time average gas flow rate is different from the flow rate section of a prior time, and the change of supply pressure at the time point is within a prescribed pressure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention monitors the usage time of a gas appliance according to the gas flow rate of the gas supply destination, and when the usage time reaches a use upper limit time predetermined according to the gas flow rate, an abnormality such as gas leakage has occurred. The present invention relates to a gas shut-off device that shuts off the gas supply.

  Some microcomputer meters arranged at gas supply destinations (gas consumers) not only measure the gas flow rate but also have a gas shut-off function. This gas shut-off function monitors the usage time of gas appliances according to the gas flow rate of the gas supply destination, and when the usage time reaches a usage upper limit time predetermined according to the gas flow rate, abnormalities such as gas leakage occur. As a result, the gas supply is cut off.

  In this microcomputer meter, the measured gas flow rate is classified according to its size, and a classification number is assigned to each classification. The gas flow rate is gradually allocated to the flow rate segment with a large segment number as the flow rate increases. The upper limit of use time is set to a shorter time as the category number is larger, that is, the gas flow rate is larger, according to the flow rate category, so that the use of a large flow rate over a long period of time can be restricted to ensure safety. ing.

  In the conventional gas shut-off function, the time during which the gas flow rate belongs to the same flow rate category is measured, and if the continuous time reaches the upper limit use time of the flow rate category, the gas supply to the gas supply destination Shut off.

  In addition, the new gas appliances can be used to increase the gas flow rate, or the gas appliances that have been used until then can be stopped and the gas flow rate can be reduced, so that If the gas flow rate changes beyond this, the upper limit time of use will be in accordance with the flow rate category after the change, and the continuous time measurement will be newly started from the time when the flow rate category changes. And, the measurement of a new continuous time from the time when such a flow rate segment is changed is a conventional case where the flow rate segment changes due to the start of use of a gas appliance used at a conventional fixed flow rate, There was no particular problem.

  On the other hand, in recent years, gas appliances equipped with a gas proportional valve and performing proportional control of the gas flow rate have become widespread.

  When a proportionally controlled gas appliance is used, the gas flow rate increases or decreases depending on the mode of use. For example, if you wash in the kitchen with a single water heater and use a shower in the bathroom, the amount of hot water used increases, so the gas flow rate increases, and as a result, the flow rate classification is one rank higher. Gas flow may occur. Conversely, if you use a single water heater to wash in the kitchen and use a shower in the bathroom, and then stop using it in the bathroom, the gas flow rate will decrease, and as a result, the flow rate classification will be one rank lower. Gas flow may occur.

  As described above, in the case of a gas appliance having a proportional control function, the gas appliance is often used across the flow rate divisions although it is a single gas appliance. In this case, since the monitoring time timer is reset when the flow rate changes, the upper limit time for use (continuous use cutoff time) is ignored, so the time used in the previous flow rate is ignored and one gas appliance is continuous. In some cases, however, the substantial time until the upper limit of use time is reached becomes long.

  As described above, in the gas shut-off function of the conventional microcomputer meter, there may be a situation where one gas appliance is continuously used even if it exceeds the upper limit use time determined for safety. There was a problem.

  The present invention has been proposed in view of the above, and it is possible to surely prevent one gas appliance from being used over the upper limit of use time, and to eliminate a security problem. The purpose is to provide.

  In order to achieve the above object, according to the first aspect of the present invention, the usage time of the gas appliance is monitored based on the gas flow rate of the gas supply destination, and the usage time is set to a use upper limit time predetermined according to the gas flow rate. A gas flow rate detecting means for detecting the gas flow rate at the gas supply destination as an average gas flow rate at a predetermined time in a gas cutoff device that shuts off the supply of gas because an abnormality such as a gas leak has occurred, A flow rate classification means for determining whether the average gas flow rate belongs to a flow rate category previously classified according to the magnitude of the average gas flow rate, and a use upper limit time set according to the flow rate category The registered upper limit time registration table, the time measuring means for measuring the continuous time in which the average gas flow rate belongs to the same flow rate category, and the upper limit of use of the flow rate category. If the time is reached, the gas shutoff means for shutting off the gas supply to the gas supply destination, the pressure change detection means for detecting the change in the supply pressure of the gas used at the gas supply destination, and the average gas flow rate detected this time The current flow rate category to which the current gas flow category belongs is different from the previous flow rate category to which the previously detected average gas flow rate belongs, and when the change in supply pressure at that time is within the specified pressure, the current flow rate category read from the upper limit time registration table And an upper limit time changing means that sets a time obtained by subtracting a continuous time in which the average gas flow rate has belonged to the previous flow rate category from the upper limit use time for the current flow rate category. .

  The invention according to claim 2 is the above-described invention according to claim 1, wherein the flow rate classification is assigned with a segment number, and the average gas flow rate is increased step by step into the flow rate segment with a larger segment number. It is designed to be distributed.

  According to a third aspect of the present invention, in the above-described second aspect of the invention, the use upper limit time is set so as to become shorter as the flow number division number increases.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects of the present invention, a change within a predetermined pressure of the supply pressure is not recognized as a new gas equipment use. It is a change.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the current gas flow classification to which the average gas flow detected this time belongs belongs to the average gas flow detected last time. The difference from the previous flow rate classification is due to the change in gas flow rate based on the use of a gas appliance that performs proportional control.

  In the gas shutoff device of the present invention, the current flow rate classification to which the average gas flow detected this time belongs is different from the previous flow rate classification to which the average gas flow detected last time belongs, and the change in supply pressure at that time is within a predetermined pressure When this is the case, the upper limit time change control is performed in which the time obtained by subtracting the continuous time that the average gas flow rate belongs to the previous flow rate category from the upper limit time for the current flow rate category is used as the upper limit time for the current flow rate category. Since it did in this way, it can prevent reliably that one gas appliance is used exceeding use upper limit time, and the problem on security can also be eliminated.

  In addition, since the upper limit time change control of the present invention is performed only when the change in the supply pressure at the time of the change of the flow rate is within a predetermined pressure, a new gas appliance that does not cause a security problem. In the case of a change in the flow rate classification due to the start of use, the application is excluded, and the upper limit time change control of the present invention can be accurately applied according to the use situation of the gas appliance.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram schematically showing the configuration of the gas cutoff device of the present invention. In FIG. 1, the gas shut-off device of the present invention monitors the usage time of a gas appliance according to the gas flow rate of the gas supply destination, and when the usage time reaches a use upper limit time TU determined in advance according to the gas flow rate, It is a device that shuts off the supply of gas because an abnormality such as leakage has occurred. Gas flow rate detection means 1, flow rate classification determination means 2, time measurement means 3, pressure change detection means 4, and upper limit time change Means 5 and gas blocking means 6 are provided.

  This gas shut-off device is provided in a microcomputer meter arranged at a gas supply destination, and each of the means 1 to 6 operates centering on the microcomputer, and the CPU operates according to the software according to the present invention stored in the memory. It is configured to include functions that operate. Further, a flow rate classification table D1 and an upper limit time registration table D2 are stored in a predetermined storage area of the microcomputer. First, the gas flow rate detection means 1 will be described in order.

  The gas flow rate detection means 1 uses a flow rate sensor 11 to detect the flow rate of a gas such as city gas or LPG that passes through the gas flow path in the microcomputer meter. Here, the flow sensor 11 is an ultrasonic sensor, a hot-wire sensor, a measuring film, or the like installed in the gas flow path. The gas flow detection means 1 crosses the gas flow path with an ultrasonic signal by the ultrasonic sensor. The flow rate of the gas transmitted from one to the other and passing through the gas flow path is detected from the propagation time, or the gas flow rate is obtained by utilizing the change of the impedance according to the gas flow rate by the hot wire sensor. Alternatively, the gas at the gas supply destination can be obtained by various methods such as counting the electrical pulse signal obtained by converting the mechanical operation of the measuring membrane with a magnet, a reed switch, a magnetoresistive element, etc. The flow rate is obtained, and the gas flow rate is integrated every predetermined time (for example, 30 seconds) and detected as an average gas flow rate Qa.

  The flow rate classification discriminating means 2 determines to which of the flow rate categories n that the average gas flow rate Qa is divided in advance according to the magnitude of the average gas flow rate Qa.

  FIG. 2 is a diagram showing an example of the flow rate classification table. As shown in FIG. 2, the average gas flow rate Qa is divided into, for example, 15 levels according to the size, and a division number is given to each division. The flow rate is increased and allocated to the flow rate segment n having a large segment number.

  The time measuring means 3 measures the continuous time TS in which the average gas flow rate Qa continuously belongs to the same flow rate segment n. In the continuous time TS, as shown in the upper limit time registration table D2 of FIG. 3, a use upper limit time TU is predetermined for each flow rate segment n. For example, a use upper limit time when the flow rate segment n is “2”. The TU is 720 minutes, the upper limit use time TU when the flow rate segment n is “5” is 390 minutes, and the upper limit use time TU is set to a shorter time as the segment number of the flow rate segment n is larger and the flow rate is larger. Therefore, it is possible to restrict the long-time use of the gas appliance having a large flow rate and to ensure safety.

  The gas shut-off means 6 shuts off the gas supply to the gas supply destination when the continuous time TS reaches the use upper limit time TU of the flow rate section n. For example, in the case where the average gas flow rate Qa continuously belongs to the same flow rate category 3 at around 70 L / h, when the continuous time TS reaches the flow rate category 3 use upper limit time TU (720 minutes), the gas The gas supply to the supply destination is shut off.

  This upper limit use time TU is changed by the upper limit time change control of the present invention when the average gas flow rate Qa satisfies a predetermined condition, and the gas supply is shut off based on the changed use upper limit time TU. . Details thereof will be described later.

  The pressure change detection means 4 detects a change in the supply pressure P of the gas used at the gas supply destination. That is, the microcomputer meter is provided with a pressure sensor 41 so as to face the gas flow path, and a change in the supply pressure P is detected based on a measurement signal of the pressure sensor 41.

  The upper limit time changing means 5 executes the upper limit time change control of the present invention when the change in the average gas flow rate Qa satisfies a predetermined condition, and changes the upper limit time TU set in the upper limit time registration table D2. Do.

  4A and 4B are explanatory diagrams of the upper limit time change control, in which FIG. 4A shows the change in the average gas flow rate Qa, FIG. 4B shows the change in the supply pressure P when the change in the supply pressure P is small, and FIG. Each shows a big time.

  In FIG. 4, the horizontal axis indicates the elapsed time, and at time t1, the average gas flow rate Qa increases, and the flow rate segment n (up to the previous time) changes to the flow rate category (n + 1) this time. The continuous time TS in which the average gas flow rate Qa continuously belongs to the flow rate segment n up to the previous time is T1.

  Further, the supply pressure P at time t1 is slightly reduced from the previous pressure in (b), and greatly reduced in (c). The pressure change ΔP (sign is −) in (b) is within a predetermined pressure (−P1 ≦ ΔP ≦ P2), for example, −1333.22 Pa (−10 mmHg) or more and −399.97 Pa (−3 mmHg). ) It is as follows. On the other hand, the pressure change ΔP (sign is −) in (c) does not fall within the predetermined pressure range (−P1 ≦ ΔP ≦ P2), and is, for example, −1599.86 Pa (−12 mmHg) or less.

  By the way, the supply pressure P is detected by a microcomputer meter when a new gas appliance starts to be used at the gas supply destination and the gas flow rate is increased, or when the gas flow rate is increased by flow control with one proportionally controlled gas appliance. The supply pressure P to be reduced once decreases at that time, and then returns with the passage of time. In addition, the pressure change ΔP increases when the gas flow rate increases when a new gas appliance starts to be used at the gas supply destination, as shown in (c). When the gas flow rate is increased by the flow rate control, the change width becomes small as shown in (b).

  In the present invention, paying attention to the change in the supply pressure P, it is determined whether the change in the average gas flow rate Qa is caused by the start of use of a new gas appliance or by one gas appliance of proportional control. That is, if the change ΔP of the supply pressure P is within a predetermined pressure (for example, −1333.22 Pa (−10 mmHg) or more and −399.97 Pa (−3 mmHg)), then the change in the average gas flow rate Qa is proportionally controlled. If the change ΔP of the supply pressure P is other than a predetermined pressure (for example, −1599.86 Pa (−12 mmHg) or less), the change in the average gas flow rate Qa at that time is a new gas appliance. Shall be due to the start of use.

  The upper limit time changing means 5 is different from the previous flow rate classification n to which the current average gas flow rate Qa to which the current detected average gas flow rate Qa belongs is different from the previous flow rate division n to which the previously detected average gas flow rate Qa belongs, and the supply at that time When the change ΔP of the pressure P is within a predetermined pressure (for example, −1333.22 Pa (−10 mmHg) or more and −399.97 Pa (−3 mmHg)), the current change in the average gas flow rate Qa is the same as that of one gas appliance. It is determined that the control is based on proportional control, and the continuous time T1 in which the average gas flow rate Qa continuously belongs to the previous flow rate division n is subtracted from the upper limit use time TU of the current flow rate division (n + 1) read from the upper limit time registration table D2. The upper limit time change control is performed with the remaining time as the new upper limit use time TU of the current flow rate classification.

  In the above description of the embodiment, the case has been described in which the average gas flow rate Qa increases in the direction in which the flow rate segment number of the average gas flow rate Qa increases. However, the flow rate segment number of the average gas flow rate Qa is small. The upper limit time change control according to the present invention can be similarly applied even when the average gas flow rate Qa decreases in the following direction.

  As described above, in the gas shutoff device according to the present invention, when the change in the average gas flow rate Qa satisfies a predetermined condition, the use upper limit time TU of the current flow rate category (n + 1) is not adopted as it is, and the current flow rate category. The time obtained by subtracting the continuous time T1 in which the average gas flow rate Qa continuously belongs to the previous flow rate section n from the upper limit use time TU of (n + 1) is set as the new use upper limit time TU of the current flow rate section. Therefore, it is possible to reliably prevent one gas appliance from being used beyond the upper limit of use time, and it is possible to eliminate a security problem.

  In addition, since the upper limit time change control of the present invention is performed only when the change ΔP of the supply pressure P at the time of changing the flow rate segment n is within a predetermined pressure, no security problem has occurred. In the case of a change in flow rate classification due to the start of use of a new gas appliance, the application is excluded, and the upper limit time change control of the present invention can be accurately applied according to the usage status of the gas appliance.

It is a block diagram which shows roughly the structure of the gas cutoff device of this invention. It is a figure which shows an example of a flow volume division table. It is a figure which shows an example of an upper limit time registration table. It is explanatory drawing of upper limit time change control, (a) is the flow rate change of the average gas flow rate Qa, (b) is when the change of the supply pressure P is small, (c) is when the change of the supply pressure P is large. Respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas flow rate detection means 2 Flow rate classification discrimination means 3 Time measurement means 4 Pressure change detection means 5 Upper limit time change means 6 Gas shut-off means 11 Flow rate sensor 41 Pressure sensor P Supply pressure ΔP Pressure change D1 Flow rate classification table D2 Upper limit time registration table Qa Average gas flow rate TS Continuous time TU Use upper limit time n Flow rate classification

Claims (5)

The gas appliance usage time is monitored based on the gas flow rate at the gas supply destination, and if the usage time reaches the upper limit usage time predetermined according to the gas flow rate, it is assumed that an abnormality such as a gas leak has occurred and gas is supplied. In the gas shut-off device that shuts off
A gas flow rate detecting means for detecting a gas flow rate at the gas supply destination as an average gas flow rate for each predetermined time;
A flow rate classification discriminating means for determining which of the flow rate categories previously classified according to the magnitude of the average gas flow rate, the average gas flow rate;
An upper limit time registration table in which the upper limit use time set according to the flow rate category is registered;
A time measuring means for measuring a continuous time in which the average gas flow rate continuously belongs to the same flow rate category;
A gas shut-off means for shutting off the gas supply to the gas supply destination when the continuous time reaches the upper limit use time of the flow rate category;
Pressure change detecting means for detecting a change in supply pressure of gas used at the gas supply destination;
When the current gas flow category to which the average gas flow detected this time belongs is different from the previous flow rate category to which the average gas flow detected last time belongs, and the change in supply pressure at that time is within the specified pressure, the upper limit time registration table From the upper limit time of the current flow rate segment read from the above, the upper limit time changing means to set the upper limit time of the current flow rate category to the time obtained by subtracting the continuous time that the average gas flow rate had belonged to the previous flow rate category,
A gas shut-off device comprising:   The gas shut-off device according to claim 1, wherein the flow rate division is assigned a division number, and the average gas flow rate is gradually allocated to the flow rate division having a larger flow rate and a larger division number.   The gas shut-off device according to claim 2, wherein the use upper limit time is set so as to become shorter as the flow number division number becomes larger.   The gas cutoff device according to any one of claims 1 to 3, wherein the change in the supply pressure within a predetermined pressure is a change that is not recognized as a new gas appliance.   The current flow rate category to which the average gas flow rate detected this time belongs is different from the previous flow rate category to which the previously detected average gas flow rate belongs, because of a change in gas flow rate based on the use of a gas appliance that performs proportional control. 5. The gas shut-off device according to any one of 4 above.

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