JP2010145120A - Device for monitoring residual quantity of gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for monitoring the residual quantity of gas which reduces the number of processes for setting a warning level. <P>SOLUTION: Acoustic transducers TD1 and TD2 are provided in a gas flow path 3 separately from each other in the flow direction. CPU 15a controls the acoustic transducers TD1 and TD2 and measures a propagation time T1 of an ultrasonic signal from one to the other of the paired acoustic transducers TD1 and TD2 and a propagation time T2 of the ultrasonic signal from the latter to the former. The CPU 15a further determines a propagation time T3 of the ultrasonic signal between the paired acoustic transducers TD1 and TD2 from which the effect of the speed of a running fluid of the gas is removed by adding up the propagation times T1 and T2 and dividing the result by two. The CPU 15a issues warning when the propagation time T3 from which the variation due to an increase or decrease of the temperature of the gas flow path 3 is removed based on a detected temperature of a temperature sensor 19 exceeds the warning level. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas remaining amount monitoring device.

  When gas is supplied from the gas container to the gas appliance, the gas in the gas container is consumed and finally the remaining amount becomes 0, but if it is used up to then, it will be "out of gas" after that The inconvenience that the gas supply becomes impossible occurs. In view of this, there has been proposed a gas remaining amount monitoring device that detects that the remaining amount of gas in the gas container has decreased and generates a warning for notifying that.

  If the gas container is exchanged in response to the warning generated from the gas remaining amount monitoring device, the gas container having a small remaining amount before “out of gas” can be replaced with another new gas container. Specifically, the gas remaining amount monitoring device causes the counter that has once reset to the initial value 0 at the time of replacement of the gas container to count the subsequent gas consumption, and the count value indicates the remaining amount warning levels 1, 2, and 3. Generate a warning every time it exceeds.

  A gas business operator who receives a warning generated from the gas remaining amount monitoring device is normally using gas in the home where the gas remaining amount monitoring device is installed due to the occurrence of a remaining amount warning level 1 warning. Confirm. Further, the gas company arranges the delivery of the gas container when the warning of the remaining amount warning level 2 occurs, and performs the replacement operation of the gas container when the warning of the remaining amount warning level 3 occurs.

Next, for example, setting examples of remaining amount warning levels 1, 2, and 3 in a general household using two 50 kg gas containers will be described. Gas can be supplied from the two gas containers of the calculation of the gas 1 m ³ as about 2 kg, the ^{50kg × 2 / 2kg = 50m 3} . In such a case, 25 m ³ corresponding to 50% of the gas that can be supplied from the gas container is set to the remaining amount warning level 1 and 30 m ³ corresponding to 60% of the gas that can be supplied from the gas container is set to the remaining amount warning level 2. The remaining amount warning level 3 is set to 40 m ³ corresponding to 80% of the gas that can be supplied from the container. The remaining amount monitoring levels 1, 2, and 3 are set manually by the gas company using a center device that can communicate with the remaining gas amount monitoring device and a setting device that can be connected to the remaining gas amount monitoring device. Is going.

  However, the conventional gas remaining amount monitoring device described above performs remaining amount management by obtaining a count value of gas consumption. For this reason, for example, if the number of gas containers is increased from one to two, the volume of gas that can be supplied from the gas container to the gas appliance also increases. Therefore, it is necessary to reset the remaining amount warning level upward. There was a problem that setting takes a lot of man-hours.

  Further, the capacity of the gas container varies depending on the temperature. More specifically, when the temperature is high as in summer, the gas expands and the capacity of the gas container increases. On the other hand, when the temperature is low as in winter, the gas is compressed and the capacity of the gas container decreases. Therefore, it is necessary to set the remaining amount warning level 1, 2 and 3 in the winter to be lower than the remaining amount warning level 1, 2 and 3 in the summer. There was a problem.

  Therefore, an object of the present invention is to provide a gas remaining amount monitoring device that reduces the number of steps for setting a warning level.

  The invention according to claim 1, which has been made to solve the above-mentioned problems, is a gas remaining amount monitoring device that monitors the remaining amount of a gas container that supplies gas to the gas device, and is supplied from the gas container to the gas device. A pair of ultrasonic transducers provided in a gas flow path through which a gas flows in a flow direction, a first propagation time of an ultrasonic signal from one of the pair of ultrasonic transducers to the other, and the other Propagation time measuring means for measuring the second propagation time of the ultrasonic signal to the one side, and the pair of ultrasonic transducers in which the influence of the flow velocity of the gas is removed from the first propagation time and the second propagation time A flow rate correction means for obtaining a third propagation time of the ultrasonic signal in between, a temperature sensor for detecting the temperature of the gas flow path, and the gas flow path from the third propagation time based on the detected temperature of the temperature sensor. By increase or decrease of temperature Temperature correction means for removing kinetic components, remaining amount warning means for generating a warning when the third propagation time in which the flow velocity and temperature are corrected by the flow velocity correction means and the temperature correction means exceeds a warning level, The present invention resides in a gas remaining amount monitoring device characterized by comprising:

  According to a second aspect of the present invention, the gas remaining amount monitoring device according to the first aspect further comprises a reporting unit that reports to the central management center when the remaining amount warning unit generates a warning. Exist.

  As described above, according to the first aspect of the present invention, since the third propagation time is not affected by the fluctuation of the capacity that the gas container can supply to the gas appliance, the number of gas containers is increased from one to two. Even if the capacity of the gas container fluctuates due to the case or the change in seasonal temperature, it is not necessary to reset the warning level, and the number of steps for setting the warning level can be reduced.

  According to the second aspect of the present invention, the gas container can be more appropriately replaced on the central management center side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an electronic gas meter 1 incorporating a gas remaining amount monitoring device of the present invention. The electronic gas meter 1 is provided in a gas supply facility 4 as shown in FIG. In the gas supply facility 4 shown in FIG. 2, the high pressure gas from the two gas containers 5A and 5B is supplied to the pressure regulator 7 via the high pressure hoses 6A and 6B. The pressure regulator 7 adjusts the high pressure gas from the gas containers 5A and 5B to a predetermined pressure.

  After the pressure-adjusted gas is supplied to the gas meter 2 through the gas pipe 9 having the closing cock 8 on the way, the gas is further passed through the gas pipe 9 and the branch gas pipe 10 branched from the gas pipe 9. And is supplied to the gas appliance 11 provided in the room. Examples of the gas appliance 11 include a gas water heater 11A, a gas stove 11B, a gas heater 11C, and a gas floor heater 11D. In addition, examples of the gas appliance 11 include a gas rice cooker, a gas dishwasher, a gas oven, a gas fan heater, a gas instantaneous water heater, and a gas heat pump (GHP) (all not shown).

  Next, the configuration of the electronic gas meter 1 will be described with reference to FIG. The illustrated electronic gas meter 1 is configured as an ultrasonic type, and includes acoustic transducers TD1 and TD2 as a pair of ultrasonic transducers, transducer interface (I / F) circuits 12a and 12b, a transmission circuit 13, and the like. And a receiving circuit 14. The acoustic transducers TD1 and TD2 are disposed in the gas flow path 3 so as to be separated from each other by a distance L in the gas flow direction Y and at an angle θ with respect to the flow direction Y.

  The two acoustic transducers TD1 and TD2 are composed of, for example, piezoelectric vibrators that operate at an ultrasonic frequency. Each transducer TD1 and TD2 is connected to a transmitter circuit 13 and a receiver circuit 14 via transducer interface (I / F) circuits 12a and 12b, respectively. The transmission circuit 13 transmits a signal for generating an ultrasonic signal by driving one of the transducers TD1 and TD2 under the control of a microcomputer (μCOM) 15 to be described later, and an oscillation circuit for this purpose. (Not shown). The receiving circuit 14 incorporates the amplifier (not shown) for processing the ultrasonic signal by inputting the signal from the other transducer TD1, TD2 that has received the ultrasonic signal that has passed through the gas flow path 3.

  The electronic gas meter 1 also has a μCOM 15 that operates according to a predetermined program. The above-described μCOM 15 includes a central processing unit (CPU) 15a that performs various processes according to programs, a ROM 15b that is a read-only memory that stores programs for processes performed by the CPU 15a, and a work area that is used in various processes in the CPU 15a. A RAM 15c, which is a readable / writable memory having a data storage area for storing various data, and the like are incorporated.

  The electronic gas meter 1 further includes a display unit 16, a communication unit 17, and an EEPROM 18, each of which is connected to the μCOM 15. The display unit 16 is a liquid crystal display (LCD) that displays various information such as an integrated value of gas usage and a warning, and performs display under the control of the μCOM 15. The communication unit 17 is connected to, for example, a telephone line, enables communication with a centralized management center (not shown) of a gas company through the telephone line, and is controlled by the μCOM 15. The EEPROM 18 is an electrically erasable / rewritable memory that can store various stored data and has various storage areas necessary for processing operations of the CPU 15a. The EEPROM 18 has various areas for storing a flow rate integrated value Qs, propagation times T1, T2, T3, warning levels L1 to L3, and the like which will be described later.

  The electronic gas meter 1 further has a temperature sensor 19. The temperature sensor 19 is provided in the gas flow path 3, detects the temperature of the gas in the gas flow path 3, and outputs it to the CPU 15a.

  Next, the operation of the electronic gas meter 1 configured as described above will be described with reference to FIG. In response to the power supply, the CPU 15a in the gas meter 1 starts the flow rate integration process. First, the CPU 15a functions as a propagation time measurement means and performs a propagation time measurement process (step S1). In the propagation time measurement process, the CPU 15a outputs a trigger signal to the transmission circuit 13 to generate a pulse burst signal, supplies it to one transducer TD1, TD2, and sends an ultrasonic signal to the one transducer TD1, TD2. generate. In addition, the receiving circuit 14 receives signals from the other transducers TD1 and TD2 that receive the ultrasonic signals transmitted from the one transducer TD1 and TD2, and captures a signal generated by the receiving circuit 14 in response thereto.

  Thereafter, the CPU 15a reverses the same operation by reversing the transducers TD1 and TD2 that generate ultrasonic signals and the transducers TD1 and TD2 that receive ultrasonic signals. Then, the CPU 15a uses the propagation time timer formed in the RAM 15c to output a trigger signal to the transmission circuit 13 to generate an ultrasonic signal of one of the transducers TD1 and TD2, and then receives this ultrasonic signal. The propagation times T1 and T2 as the first propagation time and the second propagation time until the signals generated by the other transducers TD1 and TD2 are received via the receiving circuit 14 are measured.

Thereafter, the CPU 15a performs an instantaneous flow rate calculation process for obtaining an instantaneous gas flow rate from the obtained propagation times T1 and T2 (step S2). This instantaneous flow rate calculation process will be described below. Assuming that the speed of sound is c and the flow velocity of the gas flow is v, the propagation speed of the ultrasonic signal from the upstream transducer TD1 to the downstream transducer TD2 is (c + v cos θ), and from the downstream transducer TD2 to the upstream transducer TD1. The propagation speed of the ultrasonic signal to is (c-vcos θ). Accordingly, if the distance between the transducers TD1 and TD2 is L, the propagation time T1 when the ultrasonic signal from the transducer TD1 travels in the gas flow direction Y and reaches the transducer TD2, and the ultrasonic signal from the transducer TD2 The propagation time T2 that travels in the direction opposite to the flow direction Y and reaches the transducer TD2 has values shown in the following equations (1) and (2).
T1 = L / (c + vcos θ) (1)
T2 = L / (c−v cos θ) (2)

From equations (1) and (2), v = (L / 2 cos θ) · (1 / T1-1 / T2)
= (L / 2cos θ) · {(T2−T1) / (T2 · T1)} (3)
Thus, when L is known, the flow velocity v can be obtained by measuring the propagation times T1 and T2.

T2 · T1 = L ² / {(c + vcos θ) · (c−vcos θ)}
= L ² / (c ² −v ² cos ² θ)
Since the flow velocity v is an extremely small value compared to the sound velocity c, v ² cos ² θ in the equation can be neglected to be extremely small compared to c ² , and T2 · T1 = L ² / c ² can be obtained. . And the above equation (3) finally becomes
v = {(T2-T1) · c ² } / 2L cos θ
= (T2-T1). (C ² ). (1 / 2L cos θ)
Can be rewritten. Here, when Td = (T2−T1),
v = Td · k (4)
Where k = c ² / 2L cos θ
It becomes. That is, the gas flow velocity v is obtained by multiplying the difference Td in the propagation time of the ultrasonic signal by the constant k. The instantaneous flow rate can be obtained by multiplying the gas flow velocity v by the cross-sectional area of the gas flow path 3. Thereafter, the CPU 15a further multiplies the obtained instantaneous flow rate by a sampling time to perform a flow rate calculation process (step S3) for obtaining the gas passage flow rate, and an integration process (step S4) for integrating the obtained passage flow rate. After performing the display process of displaying the passage flow rate on the display unit 16 (step S5), the process returns to step S1 again.

The CPU 15a performs a remaining amount monitoring process for monitoring the remaining amounts of the gas containers 5A and 5B in parallel with the flow rate integration process described above. Before describing the operation of the remaining amount monitoring process, the principle of the remaining amount monitoring of the present invention will be described. It is known that the propagation times T1 and T2 of the ultrasonic signals described above vary depending on three factors: gas flow velocity, gas quality, and gas temperature. The influence of the gas flow velocity can be canceled by adding the propagation time T1 and the propagation time T2 and dividing by two. That is, the propagation time T3 of the ultrasonic signal between the pair of transducers TD1 and TD2 from which the influence of the gas flow rate is removed can be expressed by the following equation (5).
T3 = L / c (5)
Further, as described above, the propagation times T1 and T2 have values shown in the following formulas (1) and (2) as described above.
T1 = L / (c + vcos θ) (1)
T2 = L / (c−v cos θ) (2)
Therefore, the value obtained by adding the propagation time T1 and the propagation time T2 and dividing by 2 is
{L (c-vcosθ) + L (c + vcosθ)} / {2 (c + vcosθ) (c-vcosθ)
= Lc / (c ² −v ² cos ² θ)
Since the flow velocity v is a very small numerical value compared to the sound velocity c, v ² cos ² θ in the equation can be negligibly small compared to c ² , and L / c = T3 can be obtained.

  The influence of the propagation time T3 due to the gas temperature can be corrected based on the temperature of the gas flow path 3 detected by the temperature sensor 19. The LP gas filled in the gas containers 5A and 5B is a mixture of propane gas and butane gas. For example, in the fully filled gas containers 5A and 5B, the mixing ratio of propane gas and butane gas is 99%: 1%, and experimental data is obtained in which the propagation time T3 obtained at this time is 266 μs. On the other hand, in the gas containers 5A and 5B that are close to running out of gas, the mixing ratio of propane gas and butane gas is 2%: 98%, and experimental data in which the propagation time T3 obtained at this time is 313 μs is obtained. This is because propane gas is vaporized first and goes out of the gas containers 5A and 5B due to the difference in vaporization characteristics between propane gas and butane gas. The electronic gas meter 1 of this embodiment performs remaining amount management from the propagation time T3 of the ultrasonic signal using this characteristic.

  Next, detailed operation of the above-described remaining amount monitoring process will be described below with reference to FIG. First, the CPU 15a functions as a flow velocity correction means, adds the propagation times T1 and T2 obtained in step S1 and divides by 2 to remove the ultrasonic signal between the pair of transducers TD1 and TD2 from which the influence of the gas flow velocity is removed. A propagation time T3 is obtained (step S6). Next, the CPU 15a takes in the detected temperature from the temperature sensor 19 (step S7). Thereafter, the CPU 15a functions as a temperature correction means, for example, by multiplying the propagation time T3 by a correction coefficient α determined according to the detected temperature, and removes the fluctuation from the propagation time T3 to the increase or decrease in the temperature of the gas flow path 3 (step). S8).

  If the propagation time T3 exceeds the remaining amount warning level L1 (Y in step S9) when the warning 1 described later has not yet occurred as a result of correction in step S6 and step S8, the CPU 15a displays the remaining amount warning means, notification After acting as a means and controlling the communication unit 17 to notify the centralized monitoring center of warning 1 (step S12), the process returns to step S6. When the warning 1 is received through the central monitoring device, the gas company confirms that the gas is being used normally.

  When the propagation time T3 exceeds the remaining amount warning level L2 (Y in step S10) in a state where the warning 2 described later has not yet occurred, the CPU 15a functions as a remaining amount warning unit and a notification unit, After controlling and notifying the centralized monitoring center of warning 2 (step S13), the process returns to step S6. When the warning 2 is received through the centralized monitoring device, the gas company arranges delivery of the gas containers 5A and 5B.

  Furthermore, when the propagation time T3 exceeds the remaining amount warning level L3 (Y in step S11) in a state where a warning 3 described later has not yet occurred, the CPU 15a functions as a remaining amount warning unit and a notification unit, After controlling and notifying the centralized monitoring device of warning 3 (step S14), the process returns to step S6.

  According to the electronic gas meter 1 described above, the propagation time T3 is not affected by fluctuations in the capacity that the gas containers 5A and 5B can supply to the gas appliance 11, so the number of gas containers 5A and 5B is increased from one to two. In this case, even if the capacities of the gas containers 5A and 5B fluctuate due to seasonal temperature changes, it is not necessary to reset the warning levels L1, L2, and L3, and the number of steps for setting the warning level can be reduced.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

It is a block diagram which shows one Embodiment of the electronic gas meter incorporating the residual amount monitoring apparatus of this invention. It is a block diagram which shows an example of the gas supply equipment incorporating the electronic gas meter shown in FIG. It is a flowchart which shows the process sequence of CPU shown in FIG. 1 in flow volume integration processing. It is a flowchart which shows the process sequence of CPU shown in FIG. 1 in residual amount monitoring processing.

Explanation of symbols

3 Gas flow path 15a CPU (propagation time measurement means, flow velocity correction means, temperature correction means, remaining amount warning means)
19 Temperature sensor TD1 Acoustic transducer (ultrasonic transducer)
TD2 Acoustic transducer (ultrasonic transducer)
Y Flow direction

Claims (2)

In the gas remaining amount monitoring device for monitoring the remaining amount of the gas container that supplies gas to the gas appliance,
A pair of ultrasonic transducers provided apart from each other in the flow direction in the gas flow path through which the gas supplied from the gas container to the gas appliance flows;
A propagation time measuring means for measuring a first propagation time of an ultrasonic signal from one of the pair of ultrasonic transducers to the other and a second propagation time of the ultrasonic signal from the other to the one;
A flow rate correction means for obtaining a third propagation time of the ultrasonic signal between the pair of ultrasonic transducers obtained by removing the influence of the flow velocity of the gas from the first propagation time and the second propagation time;
A temperature sensor for detecting the temperature of the gas flow path;
Temperature correction means for removing fluctuations due to increase or decrease of the temperature of the gas flow path from the third propagation time based on the temperature detected by the temperature sensor;
Remaining amount warning means for generating a warning when the third propagation time in which the flow velocity and temperature are corrected by the flow velocity correction means and the temperature correction means exceeds a warning level;
A gas remaining amount monitoring device comprising: The gas remaining amount monitoring device according to claim 1, further comprising reporting means for notifying the central management center when the remaining amount warning means generates a warning.

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