JP2010139285A - Determination device and pressure signal output device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a determination device and a determination method capable of preventing decline of determination accuracy in use determination of a gas apparatus or in gas leak determination. <P>SOLUTION: A gas meter 40 includes: a bypass channel 44 for connecting one side 43a receiving a pressure from a gas channel to the other side thereof 43b; and a pressure suppression part 45 provided on the bypass channel 44, for suppressing on the other side 43b, generation of a pressure change on the other side 43b based on a pressure change on one side 43a. A pressure sensor 42 includes a displacement part 42a displaced between one side 43a and the other side 43b, and a signal output part 42b for outputting a pressure signal corresponding to displacement of the displacement part 42a. A determination part 50c of a microcomputer 50 determines use of a gas apparatus 10 and a gas leak from a pressure waveform acquired based on the pressure signal output from the pressure sensor 42 by the above constitution. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a determination device and a pressure signal output device.

Conventionally, a gas supply system for supplying fuel gas to a gas appliance via a gas meter is known. In this gas supply system, a pressure regulating valve is installed at the outlet of the gas supply container. The pressure regulating valve functions to keep the downstream pressure at a constant value of about 2.9 kPa, for example (see, for example, Patent Document 1).
JP 2001-188020 A

  Here, the present applicant has invented the technique of Japanese Patent Application No. 2008-86022. In the present invention, based on the gas pressure, it is determined whether a gas appliance with a governor is used, a gas appliance without a governor is used, and whether a gas leak has occurred.

  However, in the gas supply system described in Patent Document 1, the gas pressure in the gas pipe rises due to temperature changes during the day and at night. That is, if the gas is left unused in the daytime, the temperature in the gas pipe rises and the pressure in the gas pipe from the pressure regulating valve to the gas appliance rises. The pressure rises by about 1 kPa when the temperature rises by about 3 ° C. during the day, and in some cases, the pressure in the gas pipe may reach 4 kPa. And if the gas pressure in a gas pipe rises, when judging whether or not a gas appliance with a governor is used based on the gas pressure as in the technique of Japanese Patent Application No. 2008-86022, the judgment accuracy decreases. I will invite you. In this specification, a part of the technology of Japanese Patent Application No. 2008-86022 is described. However, this description does not recognize the publicity of the technology of Japanese Patent Application No. 2008-86022.

  The present invention has been made to solve such a conventional problem, and the object of the present invention is to make a judgment that can prevent a reduction in judgment accuracy when judging the use of gas appliances or judging gas leaks. An apparatus and a pressure signal output device are provided.

  The determination device according to the present invention includes a branch pipe having a branch space branched from a gas flow path, and a branch space of the branch pipe divided into one side and the other side, so that one side can respond to pressure fluctuation in the gas flow path. A pressure sensor comprising a displacement part displaceable to the side and the other side, a signal output part for outputting a pressure signal corresponding to the displacement amount of the displacement part, and a bypass flow path connecting the one side and the other side The use of gas appliances from the pressure suppression means provided in the bypass flow path and suppressing the occurrence of pressure change on the other side based on the pressure change on one side, and the pressure waveform obtained based on the pressure signal from the pressure sensor And a judging means for judging gas leakage.

  According to this determination apparatus, the displacement portion is provided in the bypass flow path and includes pressure suppression means for suppressing the occurrence of the pressure change generated on one side on the other side, and is displaced between the one side and the other side. The signal output part which outputs the pressure signal according to the displacement amount of is provided. With such a configuration, when the pressure fluctuates rapidly, the pressure fluctuates on one side, but on the other side, the pressure is less likely to fluctuate due to the pressure suppression means, and a pressure difference is generated, thereby causing the displacement portion. Is displaced and a pressure signal is output. On the other hand, when the pressure fluctuates gently, the pressure fluctuates on one side, and the pressure fluctuates on the other side, so that the pressure difference does not occur and the displacement part does not displace and a pressure signal is not output (or slightly Only a pressure signal with a small effect on the pressure waveform is output. Further, when a gas appliance is used or a gas leak occurs, the pressure value decreases from the original pressure to a certain stable pressure. There is a difference in the decreasing component between when the pressure in the pipe is rising and when it is not. In particular, this decreasing component shows a gradual decrease. For this reason, the displacement portion is not displaced (or only slightly displaced) by the lower component, and the displacement portion is displaced by other components excluding the lower component. Therefore, the obtained pressure waveform is one in which the influence of the lowering component that is different between when the pressure in the pipe is rising and when it is not is reduced. Therefore, it is difficult to be influenced by the lowering component in determining whether to use the gas appliance or determining a gas leak, and it is possible to prevent a decrease in determination accuracy.

  In the determination device of the present invention, the displacement portion is preferably a diaphragm formed by a thin film member.

  According to this determination apparatus, since the displacement part is a diaphragm formed by a thin film member, a displacement part that is displaced by pressure fluctuation can be manufactured with a relatively inexpensive and simple structure.

  In the determination device of the present invention, it is preferable that the pressure suppression means is an orifice having a hole having a diameter smaller than the diameter of the bypass channel.

  According to this determination apparatus, since the pressure suppression means is an orifice having a hole having a diameter smaller than that of the bypass channel, the pressure suppression means can be manufactured with a relatively simple structure, and the suppression amount can be adjusted by adjusting the hole diameter. Therefore, the design can be facilitated and relatively easy manufacture can be performed.

  In the determination apparatus of the present invention, it is preferable that the determination device further includes first trigger signal output means for outputting a first trigger signal indicating that the displacement portion is displaced to one side by a predetermined amount.

  According to this determination apparatus, when the displacement portion is displaced to one side by a predetermined amount, the first trigger signal output means for outputting the first trigger signal indicating the fact is provided. This can be output, and by inputting the first trigger signal by a microcomputer or the like, it is possible to perform control according to the sudden decrease in pressure.

  In the determination device of the present invention, it is preferable that the determination device further includes a second trigger signal output means for outputting a second trigger signal indicating that the displacement portion is displaced to the other side by a predetermined amount.

  According to this determination apparatus, when the displacement portion is displaced to the other side by a predetermined amount, the second trigger signal output means for outputting the second trigger signal indicating the fact is provided. This can be output, and by inputting the second trigger signal by a microcomputer or the like, it is possible to perform control according to the rapid increase in pressure.

  Further, in the pressure signal output device of the present invention, the branch pipe having a branch space branched from the gas flow path, and the pressure fluctuation in the gas flow path are separated by separating the branch space of the branch pipe into one side and the other side. The pressure sensor is composed of a displacement part that can be displaced to one side and the other side according to the pressure, and a signal output part that outputs a pressure signal corresponding to the amount of displacement of the displacement part, and one side and the other side are connected. It is provided with a bypass flow path, and a pressure suppression means that is provided in the bypass flow path and suppresses the occurrence of a pressure change on the other side based on a pressure change on the one side.

  According to this pressure signal output device, it is difficult to be influenced by a lowering component in determining whether to use a gas appliance or determining a gas leak, thereby contributing to provision of a determination device that prevents a decrease in determination accuracy.

  According to the present invention, it is possible to provide a determination device and a pressure signal output device capable of preventing a decrease in determination accuracy in determining whether to use a gas appliance or determining a gas leak.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a gas supply system including a determination device according to an embodiment of the present invention. The gas supply system 1 supplies fuel gas to each gas appliance 10 such as a stove, a fan heater, a water heater, and a gas stove. The gas supply system 1 includes a plurality of gas appliances 10, a gas supply source regulator 20, and a pipe 31. , 32 and a gas meter (determination device) 40. In the example illustrated in FIG. 1, the gas meter 40 is described as an example of the determination device, but the determination device is not limited to the gas meter 40.

  The adjuster 20 adjusts the fuel gas from the upstream to a predetermined pressure and flows it through the first pipe 31. The adjuster 20 has a configuration in which, for example, the fuel gas is adjusted to a pressure of about 2.9 kPa and flows through the first pipe 31. The first pipe 31 connects the regulator 20 and the gas meter 40. The second pipe 32 is a pipe that connects the gas meter 40 and the gas appliance 10. The gas meter 40 measures the flow rate of the fuel gas and displays the integrated flow rate. In such a gas supply system 1, a flow path connected to the first pipe 31 and the second pipe 32 is formed in the gas meter 40, and the fuel gas flowing through the regulator 20 flows from the first pipe 31 to the gas meter 40, And the gas appliance 10 is reached through the second pipe 32 and burned in the gas appliance 10.

  The gas appliance 10 generally includes a shut-off valve 12, a governor 13, and a burner 14. The shut-off valve 12 is a valve provided in the gas appliance 10. The governor 13 has a governor inner valve 13a, and adjusts the pressure of the gas supplied to the burner 14 of the gas appliance 10 by the opening degree of the governor inner valve 13a. The pressure-adjusted fuel gas reaches the burner 14 through the nozzle 13b at the tip of the governor 13 and burns. Note that not all the gas appliances 10 have the governor 13, and some gas appliances 10 do not have the governor 13 such as a gas stove.

  FIG. 2 is a side sectional view showing an example of the governor 13 shown in FIG. In addition, in FIG. 2, only an example of the governor 13 is shown, and the configuration of the governor 13 is not limited to that shown in FIG. Further, the governor 13 shown in FIG. 2 is illustrated with the nozzle 13b shown in FIG. 1 omitted.

  As shown in FIG. 2, the governor 13 uses a part of the internal space formed by the outer wall 13c and the governor cap 13d as a gas flow path. Such a governor 13 includes a diaphragm 13e, an adjustment spring 13f, and an adjustment screw 13g in the internal space in addition to the governor inner valve 13a.

  The diaphragm 13 e is a film-like member that partitions the internal space of the governor 13. A governor inner valve 13a is attached to the diaphragm 13e on one side (flow channel side). Further, an adjustment spring 13f is attached to the other side (side not functioning as a flow path) of the diaphragm 13e. The adjustment spring 13f has a diaphragm 13e attached to one end and an adjustment screw 13g attached to the other end. The adjustment screw 13g is structured to be fixed to the inner wall of the governor 13 in which the thread groove is formed, and the compression rate of the adjustment spring 13f can be changed by changing the fixing position with the thread groove. Further, the adjusting screw 13g is not exposed to the outside, and has a structure covered with a governor cap 13d.

  The outer wall 13c of the governor 13 is formed with an air hole 13h that communicates with the other side of the diaphragm 13e. For this reason, the other side of the diaphragm 13e is air pressure. Further, in the example shown in FIG. 2, the governor inner valve 13a has a hemispherical shape, and the opening ratio of the passage port 13i can be controlled by vertical movement.

  In such a governor 13, when the gas pressure on the gas inlet side increases, the diaphragm 13e is pushed up, and at the same time, the governor inner valve 13a attached to the diaphragm 13e is also raised. Thereby, the opening ratio of the passage port 13i becomes small, and the gas flow rate decreases. On the other hand, when the gas pressure on the gas inlet side is lowered, the diaphragm 13e is lowered, and at the same time, the governor inner valve 13a attached to the diaphragm 13e is also lowered. Thereby, the opening ratio of the passage port 13i increases, and the gas flow rate increases. In this manner, the governor 13 adjusts the downstream pressure by keeping the downstream flow rate constant with respect to the upstream pressure fluctuation.

  FIG. 3 is a configuration diagram of the gas meter 40 according to the embodiment of the present invention. As shown in the figure, the gas meter 40 according to this embodiment includes a flow sensor 41, a pressure sensor 42, and a microcomputer 50.

  The flow sensor 41 is installed in the flow path in the gas meter 40 and detects the gas flow rate in the flow path. When the gas meter 40 according to the present embodiment is an ultrasonic type gas meter, the flow sensor 41 is configured by two acoustic transducers composed of, for example, piezoelectric vibrators arranged at a predetermined distance in the flow path. When the gas meter 40 according to the present embodiment is a gas meter equipped with a thermal sensor such as a flow sensor, the gas meter 40 includes a heater that generates a temperature distribution and a thermopile that generates a signal corresponding to the temperature distribution.

  The pressure sensor 42 outputs a pressure signal corresponding to the pressure change of the gas present in the flow path in the gas meter 40. That is, the pressure sensor 42 functions as a differential pressure sensor that detects a differential pressure as described later. Detailed description will be given later. In the present embodiment, the pressure sensor 42 is provided in the flow path in the gas meter 40. However, the pressure sensor 42 is not limited to this, and the first sensor that exists outside the gas meter 40 without departing from the configuration of the present invention if possible. You may install in the piping 31 side or the 2nd piping 32 side. Similarly, the installation location of the flow sensor 41 can be changed.

  In this embodiment, the signals from the flow sensor 41 and the pressure sensor 42 are directly input to the microcomputer 50 in FIG. 3, but other elements such as an amplifier may be added between the two in some cases. .

  The microcomputer 50 controls the entire gas meter 40, and performs flow rate integration control, display control, cutoff valve cutoff control, and the like. In the present embodiment, the microcomputer 50 includes a pressure detection unit (pressure detection unit) 50a, a storage unit 50b, and a determination unit (determination unit) 50c. The pressure detector 50 a detects the pressure of the fuel gas based on the pressure signal from the pressure sensor 42. The memory | storage part 50b memorize | stores the pressure value of each time detected by the pressure detection part 50a. The pressure value stored in the storage unit 50b is, for example, data of about 1 second at the maximum, and is data measured at a measurement interval of about once every 1 millisecond. A pressure waveform is obtained by accumulating pressure values at each time. The determination unit 50c determines use of the gas appliance 10 and gas leakage from the pressure waveform based on the pressure value at each time.

  Here, the determination principle of the use of the gas appliance 10 and the gas leakage by the determination unit 50c will be described. FIG. 4 is a graph showing the pressure change when the use of the gas appliance 10 with the governor is started. In FIG. 4, the vertical axis represents the pressure change amount (kPa), and the horizontal axis represents the elapsed time (seconds) after the use of the governor-equipped gas appliance 10 is started.

  When the use of the gas appliance 10 with the governor is started, the pressure becomes a stable state after showing the predetermined amplitude shown in FIG. Specifically, immediately after the start of use of the gas appliance 10 with the governor, after showing a pressure drop to just “−0.1” kPa (see symbol a1), the pressure rises to about “0.05” kPa. (See symbol a2). After that, the pressure shows a pressure drop to about “−0.05” kPa (see symbol a3), and then shows a pressure rise to about “0.05” kPa (see symbol a4). Thereafter, the pressure repeatedly oscillates while the amplitude gradually decreases, and finally becomes a stable state in which there is no pressure change.

  The reason why such pressure vibration occurs is that an adjustment spring 13 f is provided in the governor 13. That is, when the use of the gas appliance 10 with the governor is started, the adjustment spring 13f vibrates, the governor inner valve 13a also vibrates, and the opening ratio of the passage port 13i changes gradually and gradually. Because it does.

  In particular, at the start of use of the gas appliance 10 with a governor, characteristics are seen in the frequency and amplitude of pressure vibration. Specifically, since the adjustment spring 13f vibrates in small increments, the pressure shows fine vibration. As a result, the pressure waveform contains many relatively high frequency components. Moreover, since the passage opening 13i becomes larger or smaller due to the vibration of the adjustment spring 13f at the start of use of the gas appliance 10 with a governor, the pressure waveform shows a large amplitude.

なる演算式で表すことができる。ここで、Ｃは振幅を示し、ｋは摩擦力（減衰定数）を示し、ωは復元力を示し、αは初期位置を示している。この式は多くの周波数ｆ_ｉ＝ω_ｉ／２πの振動の重ね合わせであることを示している。 The pressure P is

It can be expressed by the following equation. Here, C represents the amplitude, k represents the frictional force (attenuation constant), ω represents the restoring force, and α represents the initial position. This equation indicates that this is a superposition of vibrations of many frequencies f _i = ω _i / 2π.

  FIG. 5 is a graph showing the pressure change when the use of the governorless gas appliance 10 is started. In FIG. 5, the vertical axis represents the pressure change amount (kPa), and the horizontal axis represents the elapsed time (seconds) since the use of the governorless gas appliance 10 was started.

  When the use of the governorless gas appliance 10 is started, the pressure is in a stable state after showing the predetermined amplitude shown in FIG. Specifically, immediately after the start of use of the gas appliance 10 with the governor, after showing a pressure drop to “−0.1” kPa (see b1), the pressure rises to about “0.01” kPa. (See symbol b2). Thereafter, the pressure shows a pressure drop to about “−0.05” kPa (see symbol b3). Thereafter, the pressure repeatedly vibrates with no pressure increase. Then, the amplitude gradually decreases, and finally a stable state in which there is no pressure change is obtained. The reason why such pressure vibration occurs is as follows.

  FIG. 6 is a schematic diagram showing a state of supply of fuel gas in the governorless gas appliance 10. As shown in FIG. 6, when the governorless gas appliance 10 is used, the fuel gas reaches the burner 14 and the like from the second pipe 32 through the nozzle holder 100. Here, when a gas having a flow velocity flows into the nozzle holder 100, the flow rate does not decrease suddenly due to the inertial force, but the gas is compressed and the pressure rises. Thereafter, the inflow flow velocity becomes small (in some cases, a reverse flow) due to the increased pressure, and the pressure decreases. By repeating this, vibration of compression and expansion occurs.

  As described above, the pressure oscillates when the gas appliance with governor 10 is used and when the gas appliance 10 without governor is used. However, when the pressure waveform shown in FIG. 5 is compared with the pressure waveform shown in FIG. 4, there are the following differences.

  First, the governor-equipped gas appliance 10 has a substance that vibrates finely like the adjustment spring 13f, whereas the governor-less gas appliance 10 does not have such a substance. Therefore, although the pressure waveform shown in FIG. 5 shows vibration in the same manner as the pressure waveform shown in FIG. 4, the vibration frequency as a whole is lower than the pressure waveform shown in FIG.

  Further, in the case of the gas appliance 10 with the governor, the amplitude is increased by the vibration of the adjustment spring 13f. However, in the case of the gas appliance 10 with the governor, there is no adjustment spring 13f, and vibration due to the compressibility of the nozzle holder 100 occurs. There is only. For this reason, the pressure waveform shown in FIG. 5 has a smaller amplitude than the pressure waveform shown in FIG.

  From such characteristics, the determination unit 50c of the microcomputer 50 can determine whether the gas appliance 10 with the governor is used or whether the gas appliance 10 without the governor is used.

  FIG. 7 is a graph showing a state of pressure change at the time of gas leakage. In FIG. 7, the vertical axis represents the pressure change amount (kPa), and the horizontal axis represents the elapsed time (seconds) after the gas leak occurred.

  As shown in FIG. 7, when a gas leak occurs, the pressure gradually decreases without showing a clear vibration. Thus, in the case of gas leakage, neither the vibration of the adjustment spring 13f nor the vibration due to the compressibility of the nozzle holder 100 occurs, so no clear vibration is seen in the pressure waveform.

  As described above, there is a characteristic difference in the pressure waveform between the start of use of the gas appliance 10 with governor, the start of use of the gas appliance 10 without governor, and the occurrence of gas leakage. This feature appears within a few seconds (for example, 1 second) from the start of pressure fluctuation. From the above characteristics, the determination unit 50c of the microcomputer 50 can determine whether the gas appliance 10 with the governor is used, the gas appliance 10 without the governor is used, or a gas leak.

  However, if the gas is left unused in the daytime, the temperature in the pipes 31 and 32 will rise, and the pressure in the pipes 31 and 32 from the regulator 20 to the gas appliance 10 will rise. The pressure rises by about 1 kPa when the temperature rises by about 3 ° C. during the day, and in some cases, the pressure in the pipes 31 and 32 may reach 4 kPa. When the gas pressure in the pipes 31 and 32 rises, as described with reference to FIGS. 4 to 7, it is determined whether or not a gas appliance with a governor is used based on the gas pressure. In addition, the accuracy of judgment is reduced.

  Here, in the following description, the pressure in the pipes 31 and 32 before the pressure fluctuation, such as before using the gas appliance or before the occurrence of gas leakage, is referred to as a source pressure.

  FIG. 8 is a graph showing pressure waveforms at the start of use of the gas appliance 10 when the source pressure is rising and when it is not rising. When the original pressure is not increased, the pressure value before the start of use of the gas appliance 10 is about 2.95 kPa. When the gas appliance 10 is used, the pressure value becomes about 2.8 kPa after 1 second while showing a predetermined vibration from the start of use. On the other hand, when the original pressure has increased, the pressure value before the start of using the gas appliance 10 is about 3.17 kPa. When the gas appliance 10 is used, the pressure value becomes about 2.8 kPa after 1 second while showing a predetermined vibration from the start of use.

  Thus, the pressure waveform obtained differs between when the source pressure is rising and when it is not rising. From such a difference, when the determination unit 50c determines whether or not a gas appliance with a governor is used, there is a possibility that the determination is erroneous.

  However, in the gas meter 40 according to the present embodiment, the pressure sensor 42 includes a displacement portion 42a and a signal output portion 42b, and includes a branch pipe 43, a bypass flow path 44, a pressure suppression portion 45, and the like. Therefore, it is possible to prevent a decrease in determination accuracy. FIG. 3 will be referred to again.

  First, the branch pipe 43 is a pipe branched from the gas flow path, and forms branch spaces 43a and 43b branched from the gas flow path. The pressure sensor 42 includes a displacement part 42a and a signal output part 42b. The displacement part 42a is formed by a diaphragm of a thin film member, and is configured to separate the branched spaces 43a and 43b into one side 43a and the other side 43b. Here, the one side 43a is a directly facing side facing the pressure fluctuation, and is also called a facing side facing the gas flow path. That is, the one side 43a is a side that has the same space as the gas channel without passing through the bypass channel 44. Moreover, since this displacement part 42a is formed with the thin film diaphragm, it can be displaced to the one side 43a and the other side 43b according to the pressure fluctuation of a gas flow path. The signal output part 42b is a strain gauge provided on the displacement part 42a. This strain gauge is configured to generate a signal corresponding to the amount of strain. For this reason, when the displacement part 42a displaces to the one side 43a or the other side 43b, the signal output part 42b will output the pressure signal according to the displacement amount.

  The bypass flow path 44 is a flow path that connects the one side 43a and the other side 43b. The pressure suppression unit 45 is, for example, an orifice, and the orifice is a member having a hole whose diameter is smaller than the diameter of the bypass channel 44. This orifice suppresses the occurrence of a pressure change on the other side 43b based on a pressure change on the one side 43a. That is, when the pressure in the gas flow path suddenly rises, the pressure rises on one side 43a, but on the other side 43b, the pressure is less likely to rise by the pressure suppressing portion 45. Thereby, a pressure difference arises, the displacement part 42a displaces, and a pressure signal is output. On the other hand, when the pressure rises gently, the pressure rises on one side 43a and also rises on the other side 43b. As a result, the pressure difference is not generated, the displacement part 42a is not displaced, and no pressure signal is output (or only a slight displacement of the pressure signal with little influence on the pressure waveform is output).

  The pressure sensor 42 is not limited to the flow path in the gas meter 40, but may be installed on the first pipe 31 side or the second pipe 32 side. In this case, the branch pipe 43 and the pressure suppression unit 45 are also included. Needless to say, it is installed on the first pipe 31 side or the second pipe 32 side.

  Further, when the gas appliance 10 is used, the present applicant has a pressure waveform in a section until the pressure value is stabilized (for example, a section from time “0” to “0.2” in FIG. 8). The present inventors have found that a lowering component that decreases at a constant rate and a specific component are included. The specific component is a fine vibration component when the gas appliance 10 is used, and a component that cannot be clearly described as vibration when a gas leak occurs. Furthermore, the present applicant has found that there is no significant difference in the specific component, although the decrease component differs depending on whether the source pressure is rising or not.

  In the present embodiment, since the gas meter 40 includes the pressure sensor 42, the branch pipe 43, the pressure suppression unit 45, and the like, a lowering component whose pressure gradually changes is not detected and removed, The obtained pressure waveform is based on the specific component. As a result, the same pressure waveform is obtained when the pressure in the pipes 31 and 32 rises due to the influence of the temperature and when the pressure does not, and the judgment accuracy is not lowered.

  FIG. 9 is a graph showing a pressure change waveform when the source pressure is rising and when it is not rising. As shown in FIG. 9, both waveforms have similar pressure waveforms because the drop component is removed. Thus, since the pressure waveform is similar without being affected by the pressure in the pipes 31 and 32, it is possible to prevent the determination accuracy in the determination unit 50c from being lowered.

  FIG. 3 will be referred to again. The gas meter 40 according to the present embodiment has a contact point 51 at the displacement portion 42a. This contact 51 is connected to the ground. In addition, the gas meter 40 includes a first contact 52 and a second contact 53. For this reason, when the gas pressure in the gas flow path suddenly decreases and the displacement portion 42a is displaced to the one side 43a by a predetermined amount, the contact 51 and the first contact 52 come into contact with each other. As a result, a first trigger signal indicating that the displacement portion 42a has been displaced to the one side 43a by a predetermined amount is output to the microcomputer 50. The contact 51 and the first contact 52 constitute a first trigger signal output unit.

  Similarly, when the gas pressure in the gas flow path rapidly increases and the displacement portion 42a is displaced to the other side 43b by a predetermined amount, the contact 51 and the second contact 53 come into contact with each other. Accordingly, a second trigger signal indicating that the displacement portion 42a has been displaced to the other side 43b by a predetermined amount is output to the microcomputer 50. The contact 51 and the second contact 53 constitute a second trigger signal output unit.

  With this configuration, the first and second trigger signals can be input to the microcomputer 50, and control according to a rapid decrease or increase in pressure can be performed. For example, in the present embodiment, use of the gas appliance 10 and judgment of gas leakage are performed based on pressure data of about several seconds (1 second to 2 seconds) after the fluctuation of the gas flow rate or gas pressure occurs. Therefore, when there is no change in the gas flow rate, that is, when there is no change in the gas pressure, the pressure is not detected, and only when the pressure changes suddenly and the first or second trigger signal is generated, the pressure is detected. Thus, it is possible to perform control such as storing in the storage unit 50b.

  Next, the operation of the gas meter 40 according to this embodiment will be described. FIG. 10 is a flowchart showing the operation of the gas meter 40 according to this embodiment. The process shown in FIG. 10 is executed when the microcomputer 50 inputs the first trigger signal or the second trigger signal.

  As shown in FIG. 10, first, the pressure detector 50a of the microcomputer 50 detects the gas pressure according to the pressure signal from the pressure sensor 42 (S10). Next, the storage unit 50b stores the pressure value detected in step S10 (S11). Then, the microcomputer 50 determines whether or not the measurement is finished (S12). The measurement time is several seconds (for example, 1 to 2 seconds), and the microcomputer 50 determines whether or not the several seconds have passed. When it is determined that the measurement is not finished (S12: NO), the process proceeds to step S10, and the pressure detection unit 50a detects the gas pressure according to the pressure signal from the pressure sensor 42 (S10).

  On the other hand, when it is determined that the measurement is finished (S12: YES), the determination unit 50c determines use of the gas appliance 10 or gas leakage based on the pressure waveform obtained by the storage in step S11 (S13). Thereafter, the microcomputer 50 determines whether or not there is no gas leak in the process of step S13 (S14).

  If it is determined that there is no gas leak (S14: YES), the process shown in FIG. 10 ends. On the other hand, if it is not determined that there is no gas leak (S14: NO), that is, if it is determined that there is a gas leak, the microcomputer 50 shuts off the shutoff valve and issues an alarm (S15). Thereafter, the process shown in FIG. 10 ends.

  FIG. 11 is a flowchart showing details of step S13 shown in FIG. 10, and shows processing related to use of the gas appliance 10 and determination of gas leakage. As shown in FIG. 11, first, the microcomputer 50 analyzes the frequency of the correction waveform generated in step S12 of FIG. 10 (S30) and the amplitude (S31).

  Thereafter, the microcomputer 50 determines whether or not a frequency component equal to or higher than the discriminant value is included in the waveform based on the analysis result of step S30 (S32). If it is determined that a frequency component equal to or higher than the discriminant value is included (S32: YES), that is, if the frequency is high to some extent as in the pressure waveform shown in FIG. 4, the microcomputer 50 uses the gas appliance 10 with the governor. (S33). Then, the process illustrated in FIG. 11 ends, and the process proceeds to step S14 in FIG.

  If it is determined that the frequency component equal to or greater than the discriminant value is not included in the specified value or more (S32: NO), the microcomputer 50 first determines the amplitude value of the first peak (that is, the amplitude is positive first after the pressure changes). Is the value obtained by adding a predetermined amount to the original pressure (pressure of “0” on the vertical axis in FIG. 4). It is determined whether or not this is the case (S34). When it is determined that the amplitude value of the first peak is equal to or greater than the value obtained by adding a predetermined amount to the original pressure (S34: YES), the microcomputer 50 determines that the gas appliance 10 with the governor is used (S33). Then, the process illustrated in FIG. 11 ends, and the process proceeds to step S14 in FIG.

  On the other hand, if it is determined that the amplitude value of the first mountain is not equal to or greater than the value obtained by adding a predetermined amount to the original pressure (S34: NO), the microcomputer 50 determines that the amplitude value of the first mountain is substantially equal to the original pressure. It is determined whether or not (specifically, the original pressure ± the specified value) (S35). When it is determined that the amplitude value of the first peak is substantially equal to the original pressure (S35: YES), the microcomputer 50 determines that the governorless gas appliance 10 is used (S36). Then, the process illustrated in FIG. 11 ends, and the process proceeds to step S14 in FIG.

  If it is determined that the amplitude value of the first peak is not substantially equal to the original pressure (S35: NO), the microcomputer 50 determines that the amplitude value of the first peak is equal to or less than the value obtained by subtracting a predetermined amount from the original pressure. It is determined whether or not (S37). If it is determined that the amplitude value of the first peak is equal to or less than a value obtained by subtracting a predetermined amount from the original pressure (S37: YES), the microcomputer 50 detects a flow rate that is equal to or greater than a specified amount based on a signal from the flow sensor 41. It is determined whether or not (S38).

  When it is determined that a flow rate exceeding the specified amount is detected (S38: YES), that is, the characteristics of frequency and amplitude due to the use of the gas appliance 10 cannot be obtained, the gas pressure in the flow path is reduced, and the specified amount is obtained. If the above flow rate is detected, the microcomputer 50 determines that there is a gas leak (S39). Then, the process illustrated in FIG. 11 ends, and the process proceeds to step S14 in FIG.

  By the way, when it is determined that the amplitude value of the first peak is not less than or equal to the value obtained by subtracting the predetermined amount from the original pressure (S37: NO), and when it is determined that the flow rate exceeding the specified amount is not detected (S38: NO). The microcomputer 50 determines that neither the use of the gas appliance 10 nor the gas leakage falls (S40). Then, the process illustrated in FIG. 11 ends, and the process proceeds to step S14 in FIG.

  Note that the use of the gas appliance 10 and gas leakage are not limited to those shown in FIG. 11, and may be determined by other methods, for example. For example, when the microcomputer 50 determines “YES” in step S32 or step S34, the microcomputer 50 determines that the gas appliance with governor 10 is used, but not limited to this, “YES” in both step S32 and step S34. If it is determined, it may be determined that the gas appliance with governor 10 is used.

  Moreover, the microcomputer 50 may determine that the gas appliance 10 with the governor is used when the attenuation coefficient of the pressure waveform is equal to or less than a predetermined value. Further, the microcomputer 50 determines that the amplitude value of the first peak is the amplitude value of the first valley (that is, the minimum value when the amplitude first increases in the negative direction after the pressure changes, or most throughout the whole). When the amplitude is smaller than the value when the amplitude is increased in the negative direction, it may be determined that the gas appliance 10 with the governor is used. Furthermore, you may judge use of the gas appliance 10 with a governor combining various above-mentioned content.

  Thus, according to the gas meter 40 according to the present embodiment, the pressure meter 45 is provided in the bypass flow path 44 and includes the pressure suppressing unit 45 that suppresses the occurrence of the pressure change generated on the one side 43a on the other side 43b. A signal output unit 42b that outputs a pressure signal corresponding to the amount of displacement of the displacement unit 42a that is displaced between the one side 43a and the other side 43b is provided. With such a configuration, when the pressure fluctuates rapidly, the pressure fluctuates on one side 43a, but on the other side 43b, the pressure is less likely to fluctuate by the pressure suppression unit 45, resulting in a pressure difference. As a result, the displacement part 42a is displaced and a pressure signal is output. On the other hand, when the pressure fluctuates gently, the pressure fluctuates on one side 43a, and the pressure fluctuates on the other side 43b, so that no pressure difference is generated and the displacement portion is not displaced and no pressure signal is output ( Or, only a slight displacement causes only a pressure signal with a small influence on the pressure waveform to be output). Further, when the gas appliance 10 is used or a gas leak occurs, the pressure value decreases from the original pressure to a certain stable pressure. There is a difference in the decreasing component between when the source pressure is rising and when it is not. In particular, this decreasing component shows a gradual decrease. For this reason, the displacement portion 42a is not displaced (or only slightly displaced) by the lower component, and the displacement portion 42a is displaced by other components excluding the lower component. Therefore, the obtained pressure waveform is one in which the influence of the lowering component that differs between when the original pressure is rising and when it is not is reduced. Therefore, when using the gas appliance 10 or determining the gas leakage, it is difficult to be influenced by the lowering component, and it is possible to prevent the determination accuracy from being lowered.

  Moreover, since the displacement part 42a is a diaphragm formed by the thin film member, the displacement part displaced by pressure fluctuation can be manufactured with a relatively inexpensive and simple structure.

  Moreover, since the pressure suppression part 45 is an orifice which has a hole with a diameter smaller than the bypass flow path 44, while being able to manufacture the pressure suppression part 45 by a comparatively simple structure, adjusting the suppression amount by adjusting a hole diameter. Therefore, the design can be facilitated and relatively easy manufacture can be performed.

  In addition, when the displacement part 42a is displaced to the one side 43a by a predetermined amount, the first trigger signal output part for outputting the first trigger signal indicating the fact is provided. By inputting the first trigger signal by the microcomputer 50, it is possible to perform control according to the sudden decrease in pressure.

  Further, when the displacement part 42a is displaced to the other side 43b by a predetermined amount, the second trigger signal output part for outputting the second trigger signal indicating the fact is provided. By inputting the second trigger signal by the microcomputer 50, it is possible to perform control according to the sudden increase in pressure.

  As described above, the present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment, and may be modified without departing from the gist of the present invention. For example, in the present embodiment, the pressure value is a measurement interval once per millisecond, but this is not a limitation, and the measurement interval can be changed as appropriate.

  In the present embodiment, the determination device exists as an internal configuration of the gas meter 40. However, the determination device is not limited thereto, and the determination device may be configured by being taken out from the gas meter 40.

  In the present embodiment, the pressure sensor 42 is provided with a strain gauge, but is not limited thereto, and may be provided with other configurations such as a capacitance type and a piezoresistive type.

  Furthermore, the pressure sensor 42, the branch pipe 43, and the pressure suppression unit 45 may be taken out from the gas meter 40 and configured as a pressure signal output device. In this case, it is difficult to be influenced by a lowering component in determining whether to use a gas appliance or determining a gas leak, and this can contribute to the provision of a determination device that prevents a decrease in determination accuracy.

  Furthermore, the first trigger signal output unit and the second trigger signal output unit may be configured as follows. FIG. 12 is a configuration diagram illustrating another example of the first trigger signal output unit and the second trigger signal output unit. In the example shown in FIG. 12, two branch pipes 43A and 43B are provided. The number of branch pipes 43A and 43B is not limited to two and may be three or more. Further, bypass passages 44A and 44B are provided for the respective branch pipes 43A and 43B, and pressure suppression portions 45A and 45B are provided for the respective bypass passages 44A and 44B. Further, a contact 51A and a first contact 52 are provided on the first branch pipe 43A side, and when the displacement portion 42Aa is displaced to the one side 43a by a predetermined amount, a first trigger signal indicating that is output. . On the other hand, a contact 51A and a second contact 53 are provided on the second branch pipe 43B side, and when the displacement portion 42Ba is displaced to the other side 43b by a predetermined amount, a second trigger signal indicating that is output. . Even when configured as described above, by inputting the first trigger signal by the microcomputer 50, it is possible to perform control according to the sudden decrease in pressure, and by inputting the second trigger signal by the microcomputer 50, Control according to the sudden increase in pressure can be performed.

It is a lineblock diagram of a gas supply system containing a judgment device concerning an embodiment of the present invention. FIG. 2 is a side sectional view showing an example of the governor shown in FIG. 1. It is a lineblock diagram of the gas meter concerning the embodiment of the present invention. It is a graph which shows the mode of a pressure change when the use of the gas appliance with a governor is started. It is a graph which shows the mode of a pressure change when the use of a gas appliance without a governor is started. It is the schematic which shows the mode of supply of the fuel gas in a gas appliance without a governor. It is a graph which shows the mode of the pressure change at the time of gas leak It is a graph which shows the pressure waveform at the time of the start of use of the gas appliance in the case where the original pressure is rising and the case where it is not rising. It is a graph which shows the waveform of the pressure change in the case where the source pressure is rising and the case where it is not rising. It is a flowchart which shows operation | movement of the gas meter which concerns on this embodiment. It is a flowchart which shows the detail of step S13 shown in FIG. 10, and has shown the process regarding use of a gas appliance and a gas leak determination. It is a block diagram which shows the other example of a 1st trigger signal output part and a 2nd trigger signal output part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gas supply system 10 ... Gas appliance 12 ... Shut-off valve 13 ... Governor 13a ... Governor inner valve 13b ... Nozzle 13c ... Outer wall 13d ... Governor cap 13e ... Diaphragm 13f ... Adjustment spring 13g ... Adjustment screw 13h ... Air hole 14 ... Burner 20 ... Adjuster 31 ... First pipe 32 ... Second pipe 40 ... Gas meter (judgment device)
41 ... Flow rate sensor 42 ... Pressure sensors 42a, 42Aa, 42Ab ... Displacement parts 42b, 42Ba, 42Bb ... Signal output parts 43, 43A, 43B ... Branch pipes 44, 44A, 44B ... Bypass flow path 45 ... Pressure suppression part 50 ... Microcomputer 50a ... Pressure detector (pressure detector)
50b ... Storage unit 50c ... Judgment unit (judgment means)
51 ... Contact 52 ... First contact 53 ... Second contact

Claims (6)

A branch pipe having a branch space branched from the gas flow path;
By separating the branch space of the branch pipe into one side and the other side, a displacement part that can be displaced to one side and the other side according to pressure fluctuation in the gas flow path, and a displacement amount of the displacement part A pressure sensor comprising a signal output unit for outputting a corresponding pressure signal;
A bypass flow path connecting the one side and the other side;
A pressure suppression means that is provided in the bypass flow path and suppresses the occurrence of a pressure change on the other side based on a pressure change on the one side;
Judgment means for judging use of a gas appliance and gas leakage from a pressure waveform obtained based on a pressure signal from the pressure sensor;
A judgment device comprising: The determination device according to claim 1, wherein the displacement portion is a diaphragm formed by a thin film member. The determination apparatus according to claim 1, wherein the pressure suppression unit is an orifice having a hole having a diameter smaller than a diameter of the bypass channel. 4. The apparatus according to claim 1, further comprising first trigger signal output means for outputting a first trigger signal indicating that when the displacement portion is displaced to the one side by a predetermined amount. 5. Judgment device given in the paragraph. 5. The apparatus according to claim 1, further comprising second trigger signal output means for outputting a second trigger signal indicating that when the displacement portion is displaced to the other side by a predetermined amount. Judgment device given in the paragraph. A branch pipe having a branch space branched from the gas flow path;
By separating the branch space of the branch pipe into one side and the other side, a displacement part that can be displaced to one side and the other side according to pressure fluctuation in the gas flow path, and a displacement amount of the displacement part A pressure sensor comprising a signal output unit for outputting a corresponding pressure signal;
A bypass flow path connecting the one side and the other side;
A pressure suppression means that is provided in the bypass flow path and suppresses the occurrence of a pressure change on the other side based on a pressure change on the one side;
A pressure signal output device comprising:

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