JP4932207B2 - Gas appliance determination device - Google Patents

Description

  The present invention relates to a gas appliance determination apparatus capable of determining a gas appliance installed in a gas supply line to a home and used in the home.

  A gas meter with a built-in gas flow meter is installed at the entrance of the gas supply line in each household. In addition to the basic function of measuring the gas flow rate passing through the gas supply line, this gas meter has a security function of shutting off the gas supply when an abnormal state occurs. According to this security function, forgetting to turn off the instrument or gas leakage is detected, and the gas supply is shut off by the shut-off valve in the gas meter.

  FIG. 1 is a diagram showing a set value of the safe continuous use time used for shutting off when the safe continuous use time is over, which is one of the security functions. A conventional gas meter detects the start of use of a gas, detects that the use of the gas flow rate has continued for a safe continuous use time set in accordance with the gas flow rate, and shuts off the gas. In addition, the conventional gas meter has a function of transmitting gas use status data to the gas monitoring center through a public telephone line, and the gas monitoring center continues to use gas for a predetermined continuous use time. In addition, the safety is confirmed by raising an alarm to the customer's house by telephone or the like.

  The safe continuous use time shown in Fig. 1 is set so that the shut-off time is set short on the assumption that a device with a large gas flow rate is a large water heater or a bathtub, and a device with a small gas flow rate is a gas stove. As a premise, the cut-off time is set longer. However, gas appliances with a gas consumption of 5 kW or less (about 500 L / H or less) include gas stoves and gas fan heaters that are used for a relatively long time, as well as gas stoves that are used in the kitchen. Short duration of less than 1 hour. Further, the gas flow rate of 5 KW or less includes gas leakage. Therefore, conventionally, when the gas consumption is 5 KW or less, it is required to easily and accurately discriminate the gas appliance in use, and various discrimination methods have been proposed. For example, it is the following patent documents 1-8.

  In Patent Documents 1 to 5, it is detected that the relationship between the gas supply pressure and the gas flow rate is that the square root of the gas supply pressure is proportional to the gas flow rate, and the gas appliance in use is provided with a gas governor. It is described that it is judged that it is not done.

In Patent Documents 6 to 8, a change in gas flow after the start of use of a gas appliance is registered in advance as a flow pattern for each gas appliance, and the detected flow pattern is matched with a registered flow pattern. Determining a gas appliance having a matched flow pattern as a gas appliance in use is described.
JP-A-6-249741 JP-A-6-249742 JP-A-6-265432 JP-A-7-27661 Japanese Patent Laid-Open No. 7-27658 JP 2003-148728 A JP 2003-149019 A JP 2003-194331 A

  In Patent Documents 1 to 5, when the gas supply pressure fluctuates, the gas appliance in which the gas governor capable of absorbing the fluctuation in the gas supply pressure and keeping the gas flow rate constant is mounted, and the gas in which the gas governor is not mounted. Distinguish between instruments and gas leaks and detect gas leaks with a given inference. However, such inference is not simple and not realistic.

  Furthermore, in Patent Documents 6 to 8, since it is required to store the flow patterns of a large number of gas appliances in a microcomputer in the gas meter, the cost increases, which is not realistic.

  Accordingly, an object of the present invention is to provide a gas appliance determination apparatus that can easily and accurately determine a gas appliance and detect a gas leak when the gas consumption is small.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a gas appliance determination apparatus connected to a gas supply line, the pressure detection means for detecting the pressure of the gas, and the gas supply line A flow rate detection means for detecting an instantaneous flow rate of the gas, a gas appliance determination unit for determining a gas appliance in use from the pressure detected by the pressure detection means and the flow rate detected by the flow rate detection means . When the gas appliance determination unit detects the first phenomenon in which the flow rate is proportional to the square root of the pressure with respect to the change in pressure, the pressure changes in the direction opposite to the flow rate with respect to the change in flow rate after the flow rate is generated. When the gas stove is determined when the third phenomenon continues and the first phenomenon is detected, the gas leakage is determined when the third phenomenon does not continue after the flow rate is generated. I do.

  In order to achieve the above object, according to a second aspect of the present invention, there is provided a gas appliance determination device connected to a gas supply line, the pressure detection means for detecting the pressure of the gas, and the gas supply line A flow rate detection means for detecting an instantaneous flow rate of the gas, a gas appliance determination unit for determining a gas appliance in use from the pressure detected by the pressure detection means and the flow rate detected by the flow rate detection means . When the gas appliance determination unit detects a second phenomenon in which the flow rate does not change in response to a change in pressure, the gas appliance determination unit determines a gas stove when the flow rate gradually decreases after the flow rate is generated, and the second phenomenon is determined. When detected, the gas fan heater is judged when the flow rate changes stepwise after the flow rate is generated or when the flow rate is maintained at a constant value.

  In order to achieve the above object, according to a third aspect of the present invention, there is provided a gas appliance determination device connected to a gas supply line, the pressure detection means for detecting the pressure of the gas, and the gas supply line A flow rate detection means for detecting an instantaneous flow rate of the gas, a gas appliance determination unit for determining a gas appliance in use from the pressure detected by the pressure detection means and the flow rate detected by the flow rate detection means. When the gas appliance determination unit detects that the third phenomenon in which the pressure changes in the direction opposite to the flow rate continues with respect to the change in the flow rate, the gas appliance determination unit determines that the gas appliance is not a gas leak, Further, either the gas fan heater or the gas stove is determined according to the flow rate pattern after the flow rate is generated.

  In order to achieve the above object, according to a fourth aspect of the present invention, there is provided a gas appliance determination apparatus connected to a gas supply line, comprising: a pressure detection means for detecting a gas pressure; A flow rate detection means for detecting an instantaneous flow rate of the gas, a gas appliance determination unit for determining a gas appliance in use from the pressure detected by the pressure detection means and the flow rate detected by the flow rate detection means. The gas appliance determination unit is responsive to a first phenomenon in which the flow rate is proportional to the square root of the pressure with respect to a change in pressure, a second phenomenon in which the flow rate does not change with respect to the pressure change, and a change in flow rate. On the other hand, if none of the third phenomenon in which the pressure changes in the direction opposite to the flow rate can be detected, the gas stove, gas fan heater, or gas stove Judges Zureka.

  According to the first aspect of the invention, when the first phenomenon in which the flow rate is proportional to the square root of the pressure with respect to the pressure change is detected, the use of a gas stove which is a typical example of a gas appliance without a governor; Gas leakage is estimated, but in the case of a gas stove, the flow rate changes continuously with the flow rate adjustment. The detection of the artificial flow rate adjustment of the gas stove can be detected when a third phenomenon occurs in which the pressure changes in the opposite direction in response to the flow rate change, and when there is no flow rate change due to the third phenomenon. Gas leaks can be detected. Therefore, it is possible to perform alarm communication and shut-off control corresponding to a gas stove that has a relatively short continuous use time, and further, it is possible to perform a security process by distinguishing gas leaks.

  According to the second aspect of the present invention, when the second phenomenon in which the flow rate does not change with respect to the pressure change is detected, the gas appliance has a governor and has a relatively small flow rate (for example, 5 kW or less). The gas stove or gas fan heater to be consumed can be estimated. In the gas stove, the flow rate at the gas appliance determination device gradually decreases due to the temperature rise in the gas stove due to combustion after the start of use, whereas the gas fan heater has a constant flow rate after the start of use at the maximum output. When the value is maintained and the output is medium or small, the flow rate decreases gradually after the start of use. Therefore, by detecting these phenomena, it is a gas appliance with a governor with a small gas consumption, and it is possible to distinguish between a gas stove and a gas fan heater, and it is possible to perform a security process corresponding to each.

  According to the third aspect of the present invention, when it is detected that the third phenomenon has continued, it is determined that the flow control of the gas appliance is being performed, not at least gas leakage, and the gas equipment is determined according to the flow pattern. Can be determined. Since it is determined that the gas appliance is being used appropriately instead of a gas leak, a difference can be made in the alarm processing.

  According to the fourth aspect of the invention, when neither supply pressure fluctuation nor flow control on the gas appliance side can be detected, it is possible to determine the gas leak or the type of gas appliance based on the flow rate pattern immediately after the flow rate is generated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to these embodiments, but extends to the matters described in the claims and equivalents thereof.

  FIG. 2 is a configuration diagram of a gas meter having a gas appliance determination function in the present embodiment. The gas meter 10 is connected to an upstream gas supply line 12, and is connected to a gas stove 18, a gas stove 20, a gas fan heater 22, and the like in a customer's house 16 via a downstream gas supply line 14. In the present embodiment, it is possible to distinguish gas stoves, gas stoves, and gas fan heaters, which are typical gas appliances with relatively small gas consumption, for example, 5 kW or less, and further to distinguish gas leaks.

  The gas meter 10 includes a gas flow rate detector 102 that detects an instantaneous flow rate of gas in a gas flow path, a pressure detector 104 that detects pressure in the gas flow path, and a shut-off valve 106 that blocks the gas flow path. . The gas flow rate detector 102 is composed of, for example, an ultrasonic sensor and can detect an instantaneous gas flow rate. The pressure detector 104 detects the gas pressure in the gas flow path. The change in the gas pressure is first caused by fluctuations in the upstream gas supply pressure, and secondly by the downstream flow rate. There are cases where the pressure changes due to the change (when the flow rate is changed, the pressure changes to a low pressure). Further, the gas meter 10 has a control unit 108 that calculates a gas consumption based on the flow rate detected from the gas flow rate detector 102, and this control unit 108 includes the detected gas from the pressure detector 104. It has a gas appliance determination function that monitors the pressure and the flow rate from the gas flow rate detector 102, detects the start of gas consumption, determines the gas appliance in use and detects gas leaks from the subsequent pressure and flow rate. . The gas meter 10 has a communication unit 110 capable of transmitting and receiving data to a public telephone line, etc., and transmits the determined gas appliance, gas leakage information, information on continuous use time, etc. to the gas monitoring center remote from the communication unit. To do. In addition, a cutoff command signal from the gas monitoring center is received, and the cutoff valve 106 is shut off by the control unit.

  The above gas meter is mainly configured for city gas. In the case of an LP gas gas meter, the pressure detector 104 is provided on the upstream side of the shutoff valve 106. In addition, the control unit and the communication unit for determining the gas appliance may be attached to the outside of the casing instead of the casing of the gas meter.

  A gas stove, a gas stove, a gas fan heater, and the like are installed in the customer's house 16 according to the customer, and are connected to the gas supply line 14 respectively. All of these gas appliances consume as little as 5 kW or less. A large water heater, BF, CF type bath, small water heater, etc. will be installed at the customer's house 16, but the gas consumption of these gas appliances exceeds 5 kW. These gas appliances can be distinguished from gas stoves, gas stoves, gas fan heaters and the like that consume less gas.

  On the other hand, it is not easy to distinguish between gas appliances such as gas stoves, gas stoves, and gas fan heaters that consume less gas, and gas leaks that detect a similar gas flow rate. This is because the gas flow rate is 5 KW or less. The gas appliance determination apparatus according to the present embodiment can easily and accurately perform these determinations. Hereinafter, the relationship between these gas appliances and the gas pressure and flow rate in gas leakage will be described, and the gas appliance determination logic utilizing these relationships will be described.

  As a premise, the characteristics of the gas appliance described above will be explained. The gas stove is not attached with a governor, and the output is controlled by adjusting the opening of the control valve. Gas stoves and gas fan heaters have governors, but in the case of gas stoves, simple output control such as large output and small output is only possible. On the other hand, the temperature of the gas fan heater can be set, and the output is controlled step by step according to the room temperature. When the temperature reaches the set temperature, the output is maintained at a constant value. At the time of ignition, the gas fan heater is controlled to maximum combustion (maximum flow rate) and gradually reduced to a gas flow rate corresponding to the set temperature. When the set temperature is set to the maximum value, the maximum combustion (maximum flow rate) during ignition is maintained as it is.

  FIG. 3 is a diagram showing the relationship between the gas supply pressure and the flow rate in the gas stove. In this example, the valve opening for controlling the gas flow rate in the gas stove is maintained at a constant state, and the change in the flow rate when the gas supply pressure changes is measured. Since the governor is not attached to the gas stove, when the gas supply pressure P changes, the flow rate Q changes in proportion to the square root √P of the supply pressure P.

FIG. 3A shows that when the supply pressure P is decreased stepwise, the flow rate Q is also decreased and changed stepwise. Therefore, when the supply pressure P and the flow rate Q sampled every 2 seconds are plotted on a graph of the horizontal flow rate Q and the vertical supply pressure P as shown in FIG. 3B, P = kQ ² (or Q = a √P) There are sample points on the graph. Here, k and a are both constants. That is, the flow rate Q has a relationship proportional to the square root of the supply pressure P. Therefore, in the steady state after the start of use of the gas appliance, if a phenomenon in which the flow rate Q changes in relation to the change in the measured supply pressure P in the relationship of FIG. Presumed. However, since a similar relationship is found in the case of gas leaks, it is necessary to distinguish between gas stoves and gas leaks. The method will be described later.

Therefore, in the gas appliance determination of the present embodiment, supply pressure and flow rate data at a sampling time (for example, every 2 seconds) after the start of use of the gas appliance is accumulated, and supply pressure P and flow rate Q data within a predetermined time. However, it is checked whether or not there is a correlation with the above-mentioned P = kQ ² (or Q = a√P).

  FIG. 4 is a diagram showing actual measurement data of the gas supply pressure and flow rate in the gas stove. As shown in FIG. 4 (1), the flow rate Q detected when the supply pressure P fluctuates is accompanied by a transient large fluctuation TR. Even in cases other than the transient state, the measurement value includes slight fluctuations (fluctuations) caused by sensor detection errors and the like. Therefore, when a gas appliance determination function is mounted on a gas meter, it is necessary to detect the presence or absence of the above correlation by removing such transients and fluctuations.

FIG. 4 (2) is an example in which the measured values P and Q every 2 seconds are plotted as they are on the graph of the horizontal flow rate Q and the vertical pressure P, and the actual data D1 with respect to the quadratic curve P = kQ ² . Is spreading in the horizontal direction.

  FIG. 5 is a diagram showing the relationship between the supply pressure and the flow rate when noise is removed from the measured value. FIG. 5 (1) shows an example in which the measurement value Q every 2 seconds is replaced with a value obtained by averaging the measurement value before and after the measurement value. The averaged measurement data D2 is obtained in the horizontal axis direction with respect to the quadratic curve. The spread is getting smaller. Further, FIG. 5B shows the relationship between the supply pressure and the flow rate when the fluctuation value TR generated by the transient phenomenon is removed from the measurement value Q every 2 seconds. In this case, the spread in the horizontal axis direction of the measurement data D3 from which the transient fluctuation value has been removed is further narrowed. The correlation coefficient with the quadratic curve is more “1” in the case of FIG. 5 (1) and FIG. 5 (2) than in the case where the measured values every 2 seconds in FIG. It is close.

  As can be understood from the above, when the gas meter is equipped with a gas appliance judgment function, the measurement data obtained by averaging the measured values every 2 seconds or removing the transient fluctuation values are used for the above quadratic curve. By checking whether or not there is a correlation, the discrimination accuracy can be improved.

  FIG. 6 is a diagram showing the relationship between the gas supply pressure and the flow rate of a gas appliance having a governor such as a gas fan heater. Also in this case, the change in the flow rate Q when the gas supply pressure P is changed while the opening degree of the valve for controlling the flow rate of the gas appliance is kept constant is shown. Even if the supply pressure P fluctuates up and down, the gas flow rate Q is kept constant by the function of the governor that absorbs the change in the pressure. Of course, actual measurement values include noise such as shaking, but if they are removed, the flow rate Q becomes constant.

  Therefore, if a phenomenon is detected in which the flow rate is relatively small (for example, 5 kW or less) and the flow rate Q is kept constant with respect to the change in the supply pressure P, a gas fan heater or a gas stove equipped with a governor may be estimated. it can. However, if a gas fan heater having a high security function can be distinguished from a gas stove that is not so high, the gas monitoring center can perform an optimum gas monitoring process for each. Therefore, the distinction method will be described below.

  FIG. 7 is a diagram showing gas flow control in the gas fan heater. In this example, the gas flow rate Q and the pressure P are plotted when the gas fan heater changes the flow rate Q in accordance with combustion control without changing the gas supply pressure. The gas fan heater starts to be used at time t0 and is ended at time t3. Fig. 7 (1) shows the change in flow rate when combustion is started at a low and medium temperature, and Fig. 7 (2) shows change in flow rate when combustion is started at the highest temperature. .

  The gas fan heater is provided with a governor, and in the combustion control, the gas flow rate Q is lowered so that it burns at the maximum combustion immediately after the start of combustion, and eventually converges to the set temperature. In the gas fan heater, in order to maintain complete combustion and low NOx, the relationship between the gas flow rate and the air volume by the fan is controlled by only a few control points. In other words, the optimal air volume and flow rate values are registered in advance in the controller, and the air volume and flow rate at those control points are controlled. For this reason, the flow rate control changes stepwise corresponding to the several control points. If medium and low temperatures are set at the start of combustion, the maximum combustion flow rate Qmax immediately after combustion decreases from Qmax to Q1 and Q2 in stages, and stabilizes at a flow rate value at a control point close to the set temperature. On the other hand, if the maximum temperature is set at the start of combustion, the maximum flow rate Qmax of maximum combustion immediately after combustion is controlled to be maintained as it is.

  Therefore, if the gas appliance has a fixed flow rate with respect to fluctuations in the gas supply pressure and stepwise flow control or constant flow control as shown in FIG. It can be determined that the fan heater is used.

  Even in the case of a gas fan heater, the gas pressure P decreases in response to an increase in the flow rate Q during ignition, and the gas pressure P changes in the opposite direction in response to a change in the flow rate Q. That is, when the flow rate Q increases or decreases when there is no change in the supply pressure, a third phenomenon can be found in which the pressure P detected correspondingly decreases in the opposite direction.

  FIG. 8 is a diagram showing the flow control of the gas stove and the gas stove. In this example, the gas flow rate Q and pressure P in the gas stove and gas stove are plotted without changing the gas supply pressure. At time t0, the gas stove and the gas stove start to be used, and at time t3, the use ends. FIG. 8 (1) is an example of a gas stove, which is a case where the maximum or medium combustion output is kept constant. The gas stove is equipped with a governor, but its control is such that, at most, the combustion output of large, medium and small is controlled. As shown in the figure, when the flow control by the gas stove control valve is not performed, the flow rate Q of the gas detected by the gas meter gradually decreases. In the case of a gas stove, since the fan is not provided like a gas fan heater, the temperature of the burner part of a gas stove rises with combustion. As the temperature rises, the volume of the gas in the instrument expands. Therefore, even if the flow rate of gas supplied to the instrument is controlled to be constant, the flow rate Q in the gas meter without the temperature rise decreases. This phenomenon appears in FIG.

  On the other hand, in the case of a gas fan heater, the temperature of the burner portion is constantly cooled by the fan. As shown in FIG. 7, when the opening of the control valve is not changed by the gas fan heater, the gas flow rate Q at the gas meter is changed. Is kept constant. Therefore, when the use of the gas appliance with a governor is detected and the phenomenon of FIG. 8 (1) is detected, it can be determined that the gas stove is used.

  Even in the case of a gas stove, the gas pressure P decreases corresponding to the increase in the flow rate Q at the time of ignition, and the gas pressure P increases corresponding to the decrease in the flow rate at the time of stop. That is, even in the gas stove, when there is no change in the supply pressure, a third phenomenon can be found in which when the flow rate Q increases or decreases, the pressure P detected correspondingly decreases in the opposite direction.

  In the gas stove in FIG. 8 (2), when ignited at time t0, a large amount of gas flow is detected, but when the opening of the control valve is controlled to a low output, the gas flow rate Q is controlled to a low value, After that, it keeps a constant value. In the case of a gas stove, it may be used for a long time with low heat, in which case the gas flow rate is maintained at a constant value for a long time. The gas flow rate Q of the gas fan heater also maintains a constant value, but it can be distinguished from the gas stove from the difference in the relationship between the supply pressure and the flow rate with or without the governor described with reference to FIGS.

  Even in the case of a gas stove, the gas pressure P decreases with an increase in the flow rate Q at the time of ignition, and the gas pressure P increases slightly with a decrease in the flow rate Q. That is, the third phenomenon occurs.

  FIG. 9 is a diagram showing the flow rate control and the accompanying pressure fluctuation in the gas stove and gas leakage. As described above, when the gas consumption is 5 KW or less, since the gas stove is not provided with a governor, it is detected that the change in the flow rate Q with respect to the change in the supply pressure P has a strong correlation with the curve of Q = a√P. Then, it is estimated that a gas stove is used, and it can be distinguished from a gas fan heater or a gas stove. However, in the case of a gas leak, there is a similar correlation, so it is necessary to distinguish between a gas stove and a gas leak.

  FIG. 9 (1) shows the flow rate change and pressure change when the opening degree of the control valve is controlled in the gas stove. When the gas stove is ignited at time t0, the flow rate Q increases and the pressure P decreases. Thereafter, when the flow rate Q is controlled to increase, the pressure P decreases, and conversely, when the flow rate Q is controlled to decrease, the pressure P increases. FIG. 9B shows the flow rate change and pressure change in the case of gas leakage. When a gas leak occurs at time t0, the flow rate Q increases and the pressure P decreases at that time. However, in the case of a gas leak, the flow rate Q is not controlled thereafter, so that the flow rate Q and the pressure P are kept constant.

  As described above, in the case of gas appliances and gas leaks such as gas fan heaters, gas stoves and gas stoves, the gas flow path has a structure that is released from the gas meter to the atmosphere via the supply gas line and a predetermined restriction. It has become. In such a case, if the flow rate control valve is adjusted to increase the flow rate Q, the gas pressure at the gas meter decreases, and if the flow rate Q decreases, the gas pressure at the gas meter increases. In other words, when a gas stove or gas leak is estimated, or when the gas supply pressure P fluctuates as shown in FIG. 3, the gas flow rate Q changes in proportion to the square root of the pressure P. If it does not change, the gas pressure at the gas meter changes in the opposite direction when the flow rate Q is changed. That is, even if the supply pressure from the upstream side of the gas does not fluctuate, a pressure resistance exists in the gas supply line, so that the change in the flow rate Q causes the pressure change in the reverse direction in the gas meter.

  In addition, in the case of a gas stove, artificial gas flow control is continuously performed after ignition, whereas in the case of a gas leak, there is no such artificial gas flow control and the flow rate is kept constant. Be drunk. Therefore, when the relationship between the gas flow rate and the pressure as shown in FIG. 9 is found, and the phenomenon in which the gas flow rate and the pressure fluctuate in the opposite direction after the start of gas use continuously occurs, it is determined that the gas stove. If it does not occur continuously, it can be determined that there is a gas leak.

  Based on the relationship between the flow rate and the pressure described above, the discrimination logic for distinguishing the gas fan heater, the gas stove, the gas stove, and the gas leakage at the gas consumption of 5 kW or less will be described.

[First Embodiment]
FIG. 10 is a chart for explaining the gas appliance determination logic according to the first embodiment. FIG. 10 shows three types of phenomenon patterns of gas pressure and flow rate and one type of flow rate pattern. By combining these four types of patterns, the above four types are obtained when the gas consumption is 5 KW or less. (Gas fan heater, gas stove, gas stove, gas leak) can be distinguished.

  Pattern 1 is the first phenomenon described with reference to FIG. 3. When the opening degree of the control valve of the gas appliance is constant, the flow rate Q is proportional to the square root of the pressure P with respect to the fluctuation of the gas supply pressure P. This is a fluctuating phenomenon. In this case, it is presumed that a gas appliance without a governor, typically a gas stove, or a gas leak.

  Pattern 2 is the second phenomenon described with reference to FIG. 6 and is a phenomenon in which the flow rate Q is maintained at a constant value with respect to fluctuations in the gas supply pressure P when the opening degree of the control valve of the gas appliance is constant. In this case, the gas appliance provided with the governor is estimated to be a gas fan heater or a gas stove when the gas consumption is 5 KW or less.

  Pattern 3 is the third phenomenon described with reference to FIGS. 7, 8, and 9. There was no change in the gas supply pressure, but the opening of the control valve of the gas appliance was controlled up and down, and the gas flow rate was accordingly changed. When changed, the pressure at the gas meter is a phenomenon that fluctuates in the opposite direction to the flow rate fluctuation. Such a phenomenon occurs when the flow rate is controlled on the gas appliance side and not when the gas leaks. That is, in a gas appliance such as a gas stove, the flow rate change continuously occurs after the start of use, but such a flow rate change does not occur in a gas leak. From the detection of this third phenomenon, it is possible to distinguish between the use of gas appliances and gas leakage.

  Pattern 4 is the flow rate pattern described with reference to FIGS. 7 and 8. In the gas fan heater, the gas flow rate is controlled stepwise or is kept constant, and in the gas stove, the gas flow rate gradually decreases. In this case, if the supply pressure does not fluctuate, the gas pressure changes according to the third phenomenon. On the other hand, since both the gas fan heater and the gas stove have a governor, there is a second phenomenon in which the flow rate does not change even if the supply pressure fluctuates. Therefore, when the second phenomenon is detected, the gas fan heater and the gas stove can be easily distinguished based on the flow rate change pattern.

  11 and 12 are determination flowcharts in the gas appliance determination unit in the present embodiment. The control unit in the gas meter in FIG. 2 is a determination unit having a gas appliance determination function. This control unit constantly monitors the gas pressure and flow rate. That is, the gas pressure P and the instantaneous flow rate Q are recorded (S10), and the relationship between the pressure P and the flow rate Q within a predetermined specified time (for example, 300 seconds) matches the four patterns in FIG. Monitor whether or not.

  First, it is determined whether or not there is a change in gas pressure in a steady state after the start of flow rate generation (S12). When there is no change in the gas pressure, as described in FIGS. 7 and 8, the gas fan heater and gas stove of pattern 4 in FIG. 10 and the gas stove in FIG. These distinction methods will be described later. Further, when there is a change in the gas pressure, any one of the patterns 1, 2, and 3 in FIG. 10 is detected. However, the gas pressure may change periodically even when the gas pressure changes (S14). That is, when pulsation occurs in the flow rate and pressure due to the control of the control valve or the like and a periodic change is detected, it does not correspond to the patterns 1, 2, and 3 in FIG. 10, and the gas pressure does not change. Same as the case.

If there is a change in the gas pressure and there is no pulsation (YES in S12, NO in S14), it is determined whether or not it is pattern 1 (first phenomenon) (S16). If a first phenomenon is found in which the flow rate Q changes in relation to P = kQ ² or Q = a√P with respect to the change in pressure P (YES in S16), a gas appliance without a governor (typically Gas stove) or gas leakage is estimated. If the relationship P = kQ ² or Q = a√P is not found between the pressure P and the flow rate Q (NO in S16), a gas appliance with a governor (typically a gas fan heater and a gas stove) is used. Presumed. Or when the 2nd phenomenon of the pattern 2 in which the flow volume Q does not fluctuate even if the pressure P fluctuates, a gas appliance with a governor may be estimated.

  If YES in step S16, it is checked whether the flow rate and pressure are continuously changing in pattern 3 (third phenomenon) (S18). If the third phenomenon in which the change in flow rate and the change in pressure are reversed is repeated continuously (YSE in S18), it is determined as a gas stove and a gas stove warning process is performed ( S22). If it is not repeated (NO in S18), it is determined that there is a gas leak, and a warning is issued immediately to the customer's house by telephone or the like (S26).

  In the case of NO in step S16, the gas fan heater and the gas stove are distinguished based on the flow rate pattern of pattern 4. That is, when a stepwise flow rate change is detected (YES in S50), the gas fan heater is detected (S52), and the process proceeds to processing 1. If a gradually decreasing right-down flow rate change is detected (YES in S54), a gas stove is detected (S56), and a gas stove alarm process is performed (S58). If there is no stepwise flow rate change (NO in S50) and there is no flow rate change to the right (NO in S54), it is determined as a gas fan heater (S60), and the process proceeds to step 1. The gas fan heater may be determined by detecting that the flow rate is constant.

  If a change in gas pressure is not detected in step S12 or if a periodic change is detected even if it is detected, if a stepwise change in flow rate is detected immediately after the start of flow rate generation (YES in S30), the gas A fan heater is detected (S32), and the process proceeds to processing 2. If a rightward flow rate change is detected (YES in S34), a gas stove is detected (S36), and a gas stove alarm process is performed (S38). If there is no change in the flow rate, it is estimated whether the maximum combustion or gas stove of the gas fan heater is present. A heater and a gas stove are distinguished (S40, S42, S44).

  FIG. 12 shows gas fan heater processes 1 and 2. If a gas fan heater is detected in steps S52 and S60, it is detected in step S16 that the gas appliance is equipped with a governor, so that the gas fan heater is detected with high accuracy. Therefore, in this case, the flow rate at the maximum combustion is registered in the fan heater table of the nonvolatile memory in the control unit corresponding to the process 1 (S62, S64). If you have already registered, you do not need to register again.

  Thus, if the maximum flow rate of the gas fan heater is registered, in step S40, depending on whether the flow rate of the used flow is positioned at the registered maximum flow rate, the determination S42 of the gas fan heater and the gas stove The determination can be made separately from the determination S44.

  In FIG. 12, in both cases 1 and 2, when a predetermined duration of the fan heater has elapsed, an alarm is given from the gas monitoring center to the customer's house by telephone or the like.

  In the gas stove alarm processing S22 and S46, for example, when continuous use for about one hour is detected, an alarm is given from the gas monitoring center to the customer's house by telephone or the like. However, this one hour is set shorter than the duration of the gas fan heater or gas stove. Further, in the gas stove alarm process, an alarm is given after a lapse of a shorter duration than the gas fan heater alarm process. Since the gas stove has a lower security function than the gas fan heater, the duration until the alarm is raised is set correspondingly shorter.

  As described above, based on the four patterns, the gas fan heater, the gas stove, the gas stove, and the gas leakage can be easily and accurately determined in a relatively small gas flow rate range. Therefore, based on these distinctions, the necessary alarms are given to the customer from the gas monitoring center, so that the quality of the gas monitoring service can be improved and the frequency of false alarms can be reduced.

[Second Embodiment]
In the first embodiment, the type of gas appliance and the gas leakage are determined based on the combination of the first, second, and third phenomena and the flow rate pattern. However, it is expected that the first, second, and third phenomena may occur rarely. Furthermore, it is expected that any gas appliance or gas leak cannot be determined as in the first embodiment. Even in such a case, some device determination logic is required to ensure an appropriate alarm.

  Therefore, in the second embodiment, first, the flow rate is distinguished from the case where the flow rate is larger than the reference value (for example, 500 L / h) and the case where the flow rate is small. And raise or shut off alarms during the safe continuous use time. If it is smaller, the instrument determination is performed by a method similar to the first embodiment. Furthermore, in the second embodiment, when neither the first, second, or third phenomenon can be detected and neither the pressure nor the flow rate changes, the instrument determination is performed based on the flow rate pattern immediately after the start of the flow rate generation. . First, the phenomenon of the pressure and flow rate of the gas appliance in question will be described, and then the appliance determination according to the second embodiment will be described.

  FIG. 13 is a diagram showing a phenomenon of pressure and flow rate when a high-fire state is left in a gas stove. In the figure, I means the first phenomenon and III means the third phenomenon. In this example, when ignition occurs at time t0, a third phenomenon occurs in which the flow rate Q increases and the pressure P decreases. Thereafter, the flow rate Q is maintained higher than the reference flow rate (200 to 300 L / h), and the first phenomenon continues. In this case, this is a typical phenomenon when the gas stove is left in a high fire state. Such a state can be detected on the basis that the flow rate is higher than the reference value even if the third phenomenon is detected after ignition. is there. In this case, it is desirable to raise an alarm at a relatively short time t1.

  FIG. 14 is a diagram showing the phenomenon of pressure and flow rate when the gas stove is left in medium or low heat. In this example, when ignition occurs at time t0, a third phenomenon occurs in which the flow rate Q increases and the pressure P decreases. After that, the flow rate Q is kept lower than the reference flow rate, and the first phenomenon continues. Further, there may be a fourth phenomenon (IV in the figure) in which neither the flow rate nor the pressure changes while the first phenomenon continues. If the first phenomenon continues when the flow rate is lower than the reference flow rate, it is estimated that the gas stove is left in a medium or low flame or gas leak, but the gas flow rate changes at the time of ignition. It is neglected on fire or low heat. In other words, it is required to determine the gas stove even when the fourth phenomenon continues in addition to the third phenomenon. In this case, it is desirable to raise an alarm at a time t2 of about 60 minutes, for example.

  FIG. 15 is a diagram showing the phenomenon of pressure and flow rate when the gas stove is used at the maximum output. In this example, when ignition occurs at time t0, a third phenomenon occurs in which the flow rate Q increases and the pressure P decreases. Thereafter, the flow rate control is not performed, but the flow rate Q slightly decreases and the pressure P slightly increases as described with reference to FIG. Then, when the temperature rise of the burner is saturated, the flow rate is not reduced, and thereafter the flow rate control is not performed, so the second phenomenon or the fourth phenomenon is detected. Therefore, it is required to determine the gas stove even when the fourth phenomenon continues in addition to the third phenomenon.

  FIG. 16 is a flowchart of appliance determination in the second embodiment. FIG. 17 is a chart showing the detailed appliance determination. As shown in the column of the flow rate and pressure phenomenon in the chart of FIG. 17, the third phenomenon III occurs at the start of flow generation such as the ignition of the appliance, and the first phenomenon I is detected in the steady state thereafter, There are a case where the second phenomenon II is detected, a case where the third phenomenon III is detected, and a case where the fourth phenomenon IV is detected without being detected. A determination method when each phenomenon is detected is shown.

  As shown in FIG. 16, when the generation of the flow rate is started, the third phenomenon III is detected (S70). Thereafter, the gas meter starts sampling of gas pressure and instantaneous flow rate (S72). The gas appliance starts its operation when the flow rate is turned on, and various flow rate controls are performed immediately after the start (S74). During this time, pressure and flow sampling continues.

  When the first phenomenon I is detected after the start operation (YES in S76), it is estimated whether an instrument without a governor is used or a gas leak is made, and instrument determination is performed as follows (S78). In this case, as shown in states 1 to 4 in FIG. 17, if the flow rate is 1000 L / h or more, it is determined that the gas has leaked (including release at the maximum opening of the gas plug), and this is notified to the gas center by communication. The alarm is given to the customer's house (state 1). Further, when the flow rate exceeds 200 to 300 L / h, as shown in FIG. 13, it is determined whether the gas stove has been left on a strong fire or a gas leak is detected, and it is longer than the state 1 but in a relatively short time. Alarm is raised (state 2). Further, when the flow rate is a reference value, for example, 200 to 300 L / h or less, it is estimated whether the gas stove or the gas leaks. Therefore, if the flow control according to the third phenomenon III is not performed after the flow rate is turned on, it is determined that the gas leaks (state 3). If the flow control according to the third phenomenon III is performed, the gas cooker Determined (state 4). If a gas leak in state 3 is determined, an alarm is given in a short time, and if a gas stove in state 4 is determined, an alarm is given in about 1 hour.

  Next, when the second phenomenon II is detected after the start operation (YES in S80), it is estimated that a gas appliance with a governor is being used, and appliance determination is performed as follows (S82). In this case, as shown in states 5 to 7 in FIG. 17, when the flow rate is 500 L / h or more of the reference value, it is determined as a governor device such as a water heater, and the safe continuous use according to the flow rate shown in FIG. Alarm processing is performed according to time (state 5). When the flow rate is 500 L / h or less of the reference value, it is desirable to distinguish between a gas fan heater (including an intelligent stove that can be controlled stepwise) or a gas stove. Therefore, if the flow rate gradually decreases slightly after the start of operation, it is determined as a gas stove (state 6). If the flow rate decreases stepwise after the start of operation or is kept constant, it is determined as a gas fan heater. (State 7). When judging a gas stove, give an alarm in 2 to 3 hours. This is a longer duration than the gas stove and a shorter duration than the gas fan heater. When the gas fan heater is determined, an alarm process is performed for the safe continuous use time corresponding to the usage amount shown in FIG. Or since it is a gas fan heater with a security function, alarm processing may be performed with a relatively long continuous use time.

  If the third phenomenon III is continuously detected after the start operation (YES in S84), it can be determined that at least gas leakage is used and flow control is being performed instead of gas leakage. In that case, appliance determination is performed as follows (S86). That is, as shown in states 8 to 10 in FIG. 17, when the flow rate is 500 L / h or more of the reference value, it is determined as a governor device such as a water heater, and the safe continuous use time according to the flow rate shown in FIG. The alarm processing is performed according to (state 8). On the other hand, when the flow rate is 500 L / h or less of the reference value, it is desirable to distinguish between the gas fan heater and the gas stove. This is because the possibility of gas stove is low because the flow rate control is performed. Therefore, if the flow rate pattern after the start of operation decreases stepwise after rising, it is determined as a gas fan heater (state 9), and in other flow rate patterns, it is determined as a gas stove (state 10). When the fan heater is judged, an alarm is given for a relatively long duration inherent to the fan heater, and when the gas stove is judged, an alarm is given for about one hour or manual flow control is detected. The alarm can be given with a relatively long duration like 1.

  Further, when the first and second phenomena cannot be detected after the start operation and the continuous third phenomenon cannot be detected, there is no change in the upstream supply pressure and no change in the downstream flow rate. Therefore, it is determined as the fourth phenomenon IV (S88). In that case, appliance determination is performed as follows (S90). That is, as shown in states 11 to 16 in FIG. 17, when the flow rate is 500 L / h or more of the reference flow rate, it is not possible to distinguish between gas leaks and a large instrument with a governor, so the flow rate shown in FIG. The alarm processing is performed for the continued duration (state 11). On the other hand, when the flow rate is 500 L / h or less, any one of the gas stove, the gas fan heater, and the gas stove is estimated (states 12 to 16). In this case, as described below, a distinction is made according to the flow rate pattern immediately after the start of operation.

  That is, when the flow rate is 200 to 500 L / h or less and the flow rate gradually decreases after the start of operation, it is determined as a gas stove (state 12). In addition, when the flow rate is a reference value of 500 L / h or less and the flow rate is greatly reduced immediately after the operation of the instrument is started, it is determined that the gas is stove (state 13). Furthermore, when the flow rate is 500 L / h or less and the flow rate decreases stepwise immediately after the start of the operation of the appliance, it is determined as a gas fan heater (state 14). Alternatively, if the flow rate is 500 L / h or less, the flow rate is constant immediately after the start of the operation of the instrument, and if it matches the registered maximum output flow rate value, it is determined as a gas fan heater (state 15). If it does not match the registered maximum output flow rate value, it cannot be determined in principle (state 16). The case where the discrimination is impossible is handled by the method shown in FIG.

  As described above, when the first phenomenon I is detected even once after the flow rate is generated, it can be determined that the instrument has no governor or the gas leaks, and when the second phenomenon II is detected even once. It can be determined as an instrument with a governor. If the flow rate change due to the third phenomenon continues when the first and second phenomena cannot be detected, it can be determined that the flow control by the gas appliance is performed, not at least gas leakage, Appliance determination is performed from the flow rate pattern after the operation of the appliance is started. Further, when the fourth phenomenon in which neither the pressure nor the flow rate is detected after the flow rate is generated, the instrument determination is performed based on the flow rate pattern after the operation is started. As described above, in the second embodiment, appliance determination can be performed by an optimum method according to the first to fourth phenomena.

It is a figure which shows the setting value of the safe continuation use time utilized for the interruption | blocking at the time of the safe continuation use time exceeding which is one of the security functions. It is a block diagram of the gas meter which has a gas appliance determination function in this Embodiment. It is a figure which shows the relationship between the gas supply pressure and flow volume in a gas stove. It is a figure which shows the actual measurement data of the gas supply pressure and flow volume in a gas stove. It is a figure which shows the relationship between the supply pressure at the time of removing noise from a measured value, and a flow volume. It is a figure which shows the relationship between the gas supply pressure of a gas appliance which has governors, such as a gas fan heater, and a flow volume. It is a figure which shows the relationship between the gas pressure P and the flow volume Q in a gas fan heater. It is a figure which shows the flow control of a gas stove and a gas stove. It is a figure which shows the flow rate control in a gas stove and gas leak, and the pressure fluctuation accompanying it. It is a chart explaining the gas appliance determination logic in this Embodiment. It is a determination flowchart figure in the gas appliance determination unit in this Embodiment. It is a determination flowchart figure in the gas appliance determination unit in this Embodiment. It is a figure which shows the phenomenon of the pressure and flow volume when a strong fire state is neglected with the gas stove. It is a figure which shows the phenomenon of a pressure and a flow volume when a gas stove is neglected with a medium heat or a low fire. It is a figure which shows the phenomenon of the pressure and flow volume when a gas stove is used by the maximum output. It is a flowchart figure of the instrument determination in 2nd Embodiment. It is a graph which shows the instrument determination in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Gas meter 12, 14: Gas supply line 16: Customer house 102: Gas flow rate detector 104: Pressure detector 106: Control unit, gas appliance determination unit

Claims (8)

A gas appliance determination device connected to a gas supply line,
Pressure detecting means for detecting the pressure of the gas;
A flow rate detecting means for detecting an instantaneous flow rate of gas in the gas supply line;
A gas appliance determination unit that determines a gas appliance in use from the pressure detected by the pressure detector and the flow rate detected by the flow detector;
The gas appliance determination unit includes:
When the first phenomenon in which the flow rate changes in proportion to the square root of the pressure with respect to the change in pressure is detected, the pressure changes in the direction opposite to the flow rate with respect to the change in flow rate after the generation of the flow rate. When the phenomenon is continuously occurring, the gas stove is determined. When the first phenomenon is detected, the gas leakage is determined when the third phenomenon is not continuously generated after the flow rate is generated.
When a second phenomenon is detected in which the flow rate does not change in response to a change in pressure, the gas stove is judged when the flow rate gradually decreases after the flow rate is generated, and the flow rate is detected when the second phenomenon is detected. When the flow rate changes stepwise after the occurrence of gas or when the flow rate maintains a constant value,
When it is detected that the third phenomenon, in which the pressure changes in the direction opposite to the flow rate, is detected in response to the flow rate change, it is determined that the gas appliance is not a gas leak, and the flow rate pattern after the flow rate is generated Depending on the condition, determine either the gas fan heater or the gas stove,
When none of the first phenomenon, the second phenomenon, and the third phenomenon has been detected can be detected, a gas stove, a gas fan heater, Alternatively, a gas appliance determination device that determines either a gas stove. A gas appliance determination device connected to a gas supply line,
Pressure detecting means for detecting the pressure of the gas;
A flow rate detecting means for detecting an instantaneous flow rate of gas in the gas supply line;
A gas appliance determination unit that determines a gas appliance in use from the pressure detected by the pressure detector and the flow rate detected by the flow detector;
When the gas appliance determination unit detects a first phenomenon in which the flow rate changes in proportion to the square root of the pressure with respect to a change in pressure, the pressure is opposite to the flow rate with respect to the change in flow rate after the flow rate is generated. When the gas stove is determined when the third phenomenon changing in the direction is continuously generated, and the first phenomenon is detected, the third phenomenon is not continuously generated after the flow rate is generated. A gas appliance determination apparatus characterized by determining gas leakage. A gas appliance determination device connected to a gas supply line,
Pressure detecting means for detecting the pressure of the gas;
A flow rate detecting means for detecting an instantaneous flow rate of gas in the gas supply line;
A gas appliance determination unit that determines a gas appliance in use from the pressure detected by the pressure detector and the flow rate detected by the flow detector;
When the gas appliance determination unit detects a second phenomenon in which the flow rate does not change in response to a change in pressure, the gas appliance determination unit determines a gas stove when the flow rate gradually decreases after the flow rate is generated. A gas appliance determination device that determines a gas fan heater when the flow rate changes stepwise after the flow rate is generated or when the flow rate maintains a constant value. A gas appliance determination device connected to a gas supply line,
Pressure detecting means for detecting the pressure of the gas;
A flow rate detecting means for detecting an instantaneous flow rate of gas in the gas supply line;
A gas appliance determination unit that determines a gas appliance in use from the pressure detected by the pressure detector and the flow rate detected by the flow detector;
When the gas appliance determination unit detects that the third phenomenon in which the pressure changes in the direction opposite to the flow rate continues with respect to the change in the flow rate, the gas appliance determination unit determines that the gas appliance is not a gas leak, A gas appliance determination device characterized by determining either a gas fan heater or a gas stove according to a flow rate pattern after the flow rate is generated. A gas appliance determination device connected to a gas supply line,
Pressure detecting means for detecting the pressure of the gas;
A flow rate detecting means for detecting an instantaneous flow rate of gas in the gas supply line;
A gas appliance determination unit that determines a gas appliance in use from the pressure detected by the pressure detector and the flow rate detected by the flow detector;
The gas appliance determination unit has a first phenomenon in which the flow rate is proportional to the square root of the pressure with respect to a change in pressure, a second phenomenon in which the flow rate does not change with a change in pressure, and a change in the flow rate. If none of the third phenomenon in which the pressure changes in the opposite direction to the flow rate can be detected, either the gas stove, the gas fan heater, or the gas stove is turned on according to the flow rate pattern after the flow rate is generated. A gas appliance determination device characterized by determining. In any one of Claims 1 thru | or 5,
When the detected flow rate exceeds a predetermined reference value, the gas appliance determination unit determines that the gas appliance other than the gas stove, the gas fan heater and the gas stove or a gas leak is present, and the detected flow rate is When the predetermined reference value is not exceeded, the gas appliance determination apparatus determines whether the gas stove, the gas fan heater, the gas stove, or the gas leak is present. In claim 2,
The gas appliance determination unit determines that a gas leak occurs when the detected flow rate exceeds a first reference value, and the detected flow rate is lower than the first reference value and the first reference value. When the lower second reference value is exceeded, it is determined that the gas stove is left unattended, and when the detected flow rate does not exceed the second reference value, it is determined whether the gas leak or gas stove is detected. A gas appliance determination device characterized by the above. In any one of Claims 1 thru | or 7,
The gas appliance determination unit includes the first to first data based on the data obtained by removing the detected pressure and flow rate transient components or the average value data of the detected pressure and flow rate within a predetermined time. A gas appliance determination device for detecting whether or not any of the third phenomenon.

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