JP2008014839A - Ultrasonic gas meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic gas meter capable of suppressing current consumption, along with reducing the variations in the performance of transmission and in reception, due to lowering of the voltage of a battery. <P>SOLUTION: This meter is provided with: a transmitting circuit 23 for sending a transmission signal to one ultrasonic sensor to generate an ultrasonic wave, a receiving circuit 25 for detecting the signal received from the other ultrasonic sensor for receiving the generated ultrasonic waves; a control circuit 10 for computing gas flow rate, based on the propagation time of the ultrasonic waves acquired by measuring the time interval starting from the outputting of the transmission signal up to the detection of the received signal; a display element 60 for displaying the computed gas flow rate; the battery 70 for supplying power to the control circuit, booster circuits 90a-90c for boosting the output voltage of the battery; and voltage stabilization circuits 110a-110c for stabilizing the output voltages of the booster circuits to the lowest operating voltages of the transmitting circuit, the receiving circuit, and for the displaying element, and for suppling the stabilized voltages to the trasnmitting circuit, the receiving circuit, and the display element as power sources. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic gas meter that operates using a battery as a power source, and more particularly to a technique for maintaining high performance by suppressing battery consumption.

  2. Description of the Related Art Conventionally, there is known an ultrasonic gas meter that measures the flow rate of gas based on the propagation time of ultrasonic waves transmitted and received by a pair of ultrasonic sensors arranged in a gas flow path. The ultrasonic gas meter generates and transmits an ultrasonic wave by sending a transmission signal generated by the transmission circuit to the ultrasonic sensor on the transmission side under the control of the control circuit, and transmits an ultrasonic wave transmitted from the ultrasonic sensor on the transmission side. A sound wave is received by an ultrasonic sensor on the receiving side, and a reception signal is detected by a receiving circuit. And a control circuit measures the propagation time of the ultrasonic wave between a pair of ultrasonic sensors based on the signal detected by the receiving circuit, calculates a flow volume based on the measured propagation time, and displays it on a display part. The control circuit controls opening and closing of the shut-off valve as necessary.

  In such a conventional ultrasonic gas meter, the output sound pressure of the ultrasonic wave increases due to the voltage of the transmission signal applied from the transmission circuit to the ultrasonic sensor on the transmission side during transmission. Similarly, the receiving circuit can receive an ultrasonic wave having a lower sound pressure as the power supply voltage of the amplifier is larger. However, since the conventional ultrasonic gas meter uses a battery as a driving power source, it can only apply a predetermined voltage.

  Therefore, in order to solve such a problem, Patent Document 1 discloses a magnetic detection circuit that can be used in a battery-driven electronic water meter. In this magnetic detection circuit, the current supplied from the battery is suppressed by the current limiting circuit, and the voltage of the battery is boosted by the DC / DC converter when the power switch that is switched by an external control signal is in the OFF state. When the power switch is on, the boosted signal is applied to the magnetic sensor of the detection circuit. As a result, a magnetic detection circuit capable of detecting magnetism with low current consumption and high accuracy can be obtained.

  Patent Document 2 discloses a flow meter that boosts and supplies a single battery power source to improve the reliability of flow rate detection. In this flow meter, the power supply level of the power supply means supplied to the entire flow meter is boosted by the boosting means and supplied to the flow rate detection means. As a result, the flow rate can be measured with high reliability, and the mounting density can be further reduced.

  FIG. 17 is a diagram illustrating a configuration of a power supply system of a conventional device disclosed in Patent Literature 1 and Patent Literature 2. The output of the battery 70 is directly supplied to the control circuit 10 and the shut-off valve 50 which are composed of a microcomputer (hereinafter abbreviated as “microcomputer”) and other digital circuits, but the transmission circuit 23, the reception circuit 25 and the display. The unit 60 is supplied after being boosted by the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c.

Assume that the output voltage of the battery 70 (hereinafter referred to as “battery voltage”) is 3V, the operating voltage of the transmitting circuit 23 is 9V, the operating voltage of the receiving circuit 25 is 6V, and the operating voltage of the display unit 60 is 4.5V. Then, the first booster circuit 90a supplies a voltage obtained by boosting the battery voltage three times as a power source to the transmission circuit 23, and the second booster circuit 90b receives the voltage obtained by boosting the battery voltage twice as a power source. 25, the third booster circuit 90c is adjusted to supply the display unit 60 with a voltage obtained by boosting the battery voltage by a factor of 1.5.
JP-A-6-174504 (FIG. 1) Japanese Patent No. 3206211 (FIG. 1)

  However, in the conventional technique described above, power is supplied from the battery 70 to the transmission circuit 23, the reception circuit 25, and the display unit 60 via the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c. Therefore, when the battery voltage gradually decreases due to changes in ambient temperature or long-term use, the voltage after boosting also varies. For example, when the output voltage of the battery 70 is decreased from 3V to 2V, the transmission circuit 23 changes to 6V, the reception circuit 25 to 4V, and the display unit 60 to 3V. Therefore, there is a problem in that the voltage of the transmission signal transmitted from the transmission circuit 23 to the ultrasonic sensor during transmission decreases, the output sound pressure of the ultrasonic wave fluctuates, and reception performance decreases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic gas meter that is capable of reducing fluctuations in transmission and reception performance due to a decrease in battery voltage and suppressing current consumption in an ultrasonic gas meter operated by a battery.

  In order to solve the above-described problem, the invention according to claim 1 is a transmission that generates an ultrasonic wave by sending a transmission signal to one ultrasonic sensor of a pair of ultrasonic sensors arranged in a gas flow path. Circuit, a receiving circuit that detects a reception signal from the other ultrasonic sensor that has received the ultrasonic wave generated by one ultrasonic sensor, and a transmission signal that is output from the transmission circuit and then the reception signal is detected by the reception circuit Measuring the propagation time of the ultrasonic wave by measuring the time until it is performed, and calculating the flow rate of the gas based on the measured propagation time of the ultrasonic wave, and the flow rate of the gas calculated by the control circuit A display unit for displaying, a battery for supplying power to the control circuit, a booster circuit for boosting the output voltage of the battery, and stabilizing the output voltage of the booster circuit to the minimum operating voltage of the transmitter circuit, the receiver circuit, and the display unit, The stabilized voltage Transmitting circuit as a power supply, characterized by comprising a voltage stabilizing circuit for supplying to the receiving circuit and a display unit.

  According to a second aspect of the present invention, there is provided a transmission circuit for generating a ultrasonic wave by transmitting a transmission signal to one ultrasonic sensor of a pair of ultrasonic sensors disposed in a gas flow path, and one ultrasonic wave A reception circuit that detects the reception signal from the other ultrasonic sensor that has received the ultrasonic wave generated by the sensor, and measures the time from when the transmission signal is output to when the reception signal is detected by the transmission circuit A control circuit that measures the propagation time of the ultrasonic wave, calculates a gas flow rate based on the measured propagation time of the ultrasonic wave, a display unit that displays the gas flow rate calculated by the control circuit, and a control A battery that supplies power to the circuit, an input-side switch that opens and closes in response to an operation start signal intermittently output from the control circuit, and a booster circuit that boosts the voltage sent from the battery via the input-side switch The output of the booster circuit A voltage stabilization circuit that stabilizes the voltage to the minimum operating voltage of the transmission circuit, the reception circuit, and the display unit, and an operation start signal that is intermittently output from the control circuit, according to the time during which the transmission circuit and the reception circuit are operated. Whether the output of the voltage stabilization circuit is supplied to the transmission circuit and the reception circuit as a power supply by delaying and outputting the power supply switch control signal as a power supply switch control signal and opening and closing according to the power supply switch control signal from the delay circuit And an output side switch for controlling whether or not.

  According to the first aspect of the present invention, since the minimum operating voltage is supplied from the voltage stabilization circuit to the transmission circuit, the reception circuit, and the display unit, even if the battery voltage fluctuates, the transmission circuit, the reception circuit, and There is no change in the characteristics of the display section. In addition, since the minimum operating voltage is supplied to the transmission circuit, the reception circuit, and the display unit, current consumption can be reduced. As a result, the consumption current of the ultrasonic gas meter can be suppressed, the life of the ultrasonic gas meter can be extended, and the capacity of the battery can also be suppressed.

  According to the second aspect of the present invention, the power consumption of the transmission circuit and the reception circuit varies depending on the number of ultrasonic measurements. Therefore, when the power consumption is large, the delay time by the delay circuit is set long, and the power consumption When the time is small, by setting the delay time short, the consumption of the ultrasonic gas meter battery can be further suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent components as those of the ultrasonic gas meter described in the background art section are denoted by the same reference numerals as those used in the background art section.

  FIG. 1 is a diagram illustrating a configuration of an ultrasonic gas meter according to Embodiment 1 of the present invention. This ultrasonic gas meter guides gas supplied from the outside to the inside from the gas inlet 1, and passes through the gas flow path 3 formed inside to the gas equipment (not shown) of the customer from the gas outlet 5. It is configured to send out.

  In the gas flow path 3, the shut-off valve 50, the first ultrasonic sensor 21, the second ultrasonic sensor 22, and the pressure sensor 30 are sequentially arranged from the upstream side. A control circuit 10 is provided inside the ultrasonic gas meter. The control circuit 10 includes a first ultrasonic sensor 21, a second ultrasonic sensor 22, a pressure sensor 30, a vibration sensor 40, and a cutoff valve 50. The display unit 60, the battery 70, and the communication circuit 80 (see FIG. 2) are connected. The first ultrasonic sensor 21 and the second ultrasonic sensor 22 constitute a part of the weighing circuit 20 described later. The vibration sensor 40 is disposed at a predetermined portion of the ultrasonic gas meter, and the display unit 60 is disposed on the front surface.

  FIG. 2 is a block diagram illustrating an electrical configuration of the ultrasonic gas meter according to the first embodiment of the present invention. This ultrasonic gas meter is electrically composed of a control circuit 10, a metering circuit 20, a pressure sensor 30, a seismic device 40, a shutoff valve 50, a display unit 60, a battery 70 and a communication circuit 80.

  The control circuit 10 includes, for example, a microcomputer and other digital circuits, and controls the entire ultrasonic gas meter. The measuring circuit 20 integrates the amount of gas used. Details of the weighing circuit 20 will be described later. The pressure sensor 30 detects the pressure inside the gas flow path 3 and outputs it as a pressure signal. The pressure sensor 30 detects the pressure of the gas flow path 3 from the outside to the gas equipment of the consumer in the normal state where the shut-off valve 50 is open, and in the state where the shut-off valve 50 is closed, the ultrasonic sensor The pressure in the gas flow path 3 from the gas meter to the customer's gas equipment is detected.

  The seismic device 40 detects vibration applied to the ultrasonic gas meter and outputs it as a seismic signal. The shut-off valve 50 is provided in the middle of the gas flow path 3 and upstream of the first ultrasonic sensor 21. The shut-off valve 50 is opened and closed according to a control signal from the control circuit 10 and controls the shut-off and passage of the gas flowing through the gas flow path 3.

  The display unit 60 includes a display member such as an LED (light emitting diode) or an LCD (liquid crystal display element). In response to a control signal from the control circuit 10, the display unit 60 displays a message indicating that when an abnormality such as the amount of gas used or gas leakage occurs. The battery 70 supplies power to each part of the ultrasonic gas meter. In response to a control signal from the control circuit 10, the communication circuit 80 normally sends an accumulated amount of gas used by a consumer to the center, and when an abnormality such as gas leakage occurs, a message indicating that fact is sent to the center. Send to.

  Next, details of the weighing circuit 20 will be described. As shown in FIG. 2, the measuring circuit 20 includes a first ultrasonic sensor 21, a second ultrasonic sensor 22, a transmission circuit 23, a reception circuit 25, a time measurement circuit 26, a first changeover switch 27a, and a second changeover switch 27b. It is composed of

  The first ultrasonic sensor 21 and the second ultrasonic sensor 22 are composed of piezoelectric elements, and are installed facing the inside of the gas flow path 3. The first ultrasonic sensor 21 generates an ultrasonic wave when an electrical signal as a transmission signal is applied. The ultrasonic wave generated by the first ultrasonic sensor 21 passes through the gas flow path 3 and reaches the second ultrasonic sensor 22. The second ultrasonic sensor 22 converts the received ultrasonic wave into an electrical signal and outputs it as a received signal. Similarly, the second ultrasonic sensor 22 generates an ultrasonic wave when an electrical signal as a transmission signal is applied. The ultrasonic wave generated by the second ultrasonic sensor 22 passes through the gas flow path 3 and reaches the first ultrasonic sensor 21. The first ultrasonic sensor 21 converts the received ultrasonic wave into an electrical signal and outputs it as a received signal.

  When an ultrasonic wave propagates through the gas flow path 3, if the gas flows through the gas flow path 3, the propagation of the ultrasonic wave is superimposed on the gas flow velocity. Therefore, the propagation time of the ultrasonic wave between the first ultrasonic sensor 21 and the second ultrasonic sensor 22 varies depending on the gas flow velocity. The control circuit 10 calculates the gas flow rate and flow rate based on the difference in propagation time, and integrates the amount of gas used and detects an abnormality.

  The transmission circuit 23 generates a transmission signal and a clock start signal in response to an instruction from the control circuit 10. Whether the transmission signal is sent to the first ultrasonic sensor 21 or the second ultrasonic sensor 22 is determined by the setting state of the first changeover switch 27a or the second changeover switch 27b that is switched by an instruction from the control circuit 10. The The clock start signal generated by the transmission circuit 23 is sent to the time measurement circuit 26.

  The reception circuit 25 receives a reception signal transmitted from the first ultrasonic sensor 21 or the second ultrasonic sensor 22. Which of the first ultrasonic sensor 21 and the second ultrasonic sensor 22 receives the reception signal is determined by the setting state of the first changeover switch 27a or the second changeover switch 27b that is switched according to an instruction from the control circuit 10. . The reception circuit 25 that has received the reception signal generates a counter stop signal and sends it to the time measurement circuit 26.

  The time measurement circuit 26 measures the time from when the transmission signal is output from the transmission circuit 23 to when the reception circuit 25 obtains the reception signal. Specifically, the time measurement circuit 26 receives a clock start signal from the transmission circuit 23, starts timing with a counter (not shown), and receives a counter stop signal from the reception circuit 25 to stop timing with the counter. . A time signal measured by the time measuring circuit 26, that is, a measurement signal representing the contents of the counter is sent to the control circuit 10.

  The first changeover switch 27a and the second changeover switch 27b are configured to switch the transmission direction of the ultrasonic wave according to an instruction from the control circuit 10, so that the transmission circuit 23, the reception circuit 25, the first ultrasonic sensor 21, and the second ultrasonic switch 21b are switched. The combination with the sonic sensor 22 is switched. This makes it possible to measure the propagation time of the ultrasonic wave propagating in the gas flow direction and the propagation time of the ultrasonic wave propagating in the opposite direction to the gas flow, and eliminate the influence of the sound velocity from the gas flow velocity calculated from both. it can.

  In the measuring circuit 20, the ultrasonic wave generated by the first ultrasonic sensor 21 (or the second ultrasonic sensor 22) by the transmission signal from the transmission circuit 23 propagates through the gas flow path 3, and the second ultrasonic sensor 22. (Or the time until the reception circuit 25 receives the reception signal generated by being received by the first ultrasonic sensor 21) is measured. The control circuit 10 calculates the flow velocity and flow rate of the gas flowing through the gas flow path 3 from the measurement signal indicating the propagation time of the ultrasonic wave sent from the measurement circuit 20. The ultrasonic gas meter repeats the above operation and measures the flow rate by the so-called sing-around method. In addition, reduction of the consumption current in an ultrasonic gas meter is aimed at by each said component being driven intermittently.

  FIG. 3 is a block diagram illustrating a power supply system of the ultrasonic gas meter according to the first embodiment of the present invention. In the following, it is assumed that the output voltage (battery voltage) of the battery 70 is 3V, the minimum operating voltage of the transmitting circuit 23 is 6V, the minimum operating voltage of the receiving circuit 25 is 4V, and the minimum operating voltage of the display unit 60 is 3V. Shall.

  The power supply system of the ultrasonic gas meter includes a control circuit 10, a transmission circuit 23, a reception circuit 25, a cutoff valve 50, a display unit 60, a battery 70, a first booster circuit 90a, a second booster circuit 90b, a third booster circuit 90c, The first voltage stabilizing circuit 110a, the second voltage stabilizing circuit 110b, and the third voltage stabilizing circuit 110c are included. The first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c may be simply referred to as a booster circuit. Further, the first voltage stabilization circuit 110a, the second voltage stabilization circuit 110b, and the third voltage stabilization circuit 110c may be simply referred to as a voltage stabilization circuit.

  The battery voltage output from the battery 70 is supplied to the power supply lines of the control circuit 10, the first booster circuit 90a, the second booster circuit 90b, the third booster circuit 90c, and the shutoff valve 50. The first booster circuit 90a boosts the battery voltage from the battery 70 to a voltage higher than 6V, which is the lowest operating voltage of the transmission circuit 23, for example, 9V, which is three times higher, and sends the boosted voltage to the first voltage stabilizing circuit 110a. The first voltage stabilizing circuit 110 a converts the voltage from the first booster circuit 90 a into 6 V, which is the lowest operating voltage of the transmission circuit 23, and supplies it to the power supply line of the transmission circuit 23.

  The second booster circuit 90b boosts the battery voltage from the battery 70 to a voltage higher than 4V, which is the lowest operating voltage of the receiving circuit 25, for example, 6V, which is doubled, and sends the boosted voltage to the second voltage stabilizing circuit 110b. The second voltage stabilizing circuit 110 b converts the voltage from the second booster circuit 90 b into 4 V, which is the lowest operating voltage of the receiving circuit 25, and supplies it to the power supply line of the receiving circuit 25.

  The third booster circuit 90c boosts the battery voltage from the battery 70 to a voltage higher than 3V, which is the lowest operating voltage of the display unit 60, for example, 4.5V, which is 1.5 times higher, to the third voltage stabilizing circuit 110c. send. The third voltage stabilizing circuit 110 c converts the voltage from the third booster circuit 90 c into 3 V, which is the lowest operating voltage of the display unit 60, and supplies the converted voltage to the power supply line of the display unit 60.

  The minimum operating voltage is supplied from the first voltage stabilization circuit 110a, the second voltage stabilization circuit 110b, and the third voltage stabilization circuit 110c in the previous stage to the power supply lines of the transmission circuit 23, the reception circuit 35, and the display unit 60, respectively. Therefore, even if the battery voltage varies, the characteristics of the transmission circuit 23, the reception circuit 35, and the display unit 60 do not change. Further, since the minimum operating voltage is supplied to the transmission circuit 23, the reception circuit 35, and the display unit 60, current consumption is also reduced.

  FIG. 4 is a circuit diagram showing a detailed configuration of the first booster circuit 90a shown in FIG. The first booster circuit 90a is a booster circuit adopting a charge pump system, and includes an oscillation circuit 91, an inverting logic circuit 92, a drive circuit 93, a drive circuit 94, a drive circuit 95, a capacitor 96, a diode 97, a diode 98, and a capacitor 99. , A diode 100 and a capacitor 101.

  The oscillation circuit 91 generates an oscillation signal in which the ground voltage (0 V) and the battery voltage (3 V) alternate, and sends the oscillation signal to the inverting logic circuit 92, the drive circuit 94, and the drive circuit 95. The inverting logic circuit 92 inverts the input oscillation signal and sends it to the drive circuit 93. The drive circuit 93 is disposed between the positive electrode of the battery 70 and the ground, and sends the ground voltage or the battery voltage to one end of the capacitor 96 according to the signal sent from the inverting logic circuit 92.

  The drive circuit 94 is disposed between the positive electrode of the battery 70 and the ground, and sends a ground voltage or a battery voltage to the anode of the diode 97 according to the oscillation signal sent from the oscillation circuit 91. The drive circuit 95 is disposed between the positive electrode of the battery 70 and the ground, and sends the ground voltage or the battery voltage to one end of the capacitor 99 in accordance with the oscillation signal sent from the oscillation circuit 91.

  The other end of the capacitor 96 is connected to the anode of the diode 98. The cathode of the diode 97 is connected to the connection point between the other end of the capacitor 96 and the anode of the diode 98. The cathode of the diode 98 is connected to the other end of the capacitor 99 and the anode of the diode 100. The cathode of the diode 100 is connected to one end of the capacitor 101, and the other end of the capacitor 101 is grounded. The voltage at one end of the capacitor 101 is sent to the first voltage stabilizing circuit 110a as the output of the first booster circuit 90a.

  Next, the operation of the first booster circuit 90a configured as described above will be described with reference to the transition diagram showing the voltage transition of each part shown in FIG.

  First, in the section T0 which is an initial state, the oscillation circuit 91 outputs a battery voltage (3V). Thus, since the ground voltage (0V) obtained by inverting the battery voltage output from the oscillation circuit 91 by the inverting logic circuit 92 is input to the drive circuit 93, the output (point a) becomes 3V. Further, since the battery voltage (3V) is input to the drive circuit 94 and the drive circuit 95, the output (point b) of the drive circuit 94 and the output (point c) of the drive circuit 95 become 0V. In this state, the point d that is the connection point between the capacitor 96 and the diode 98, the point e that is the connection point between the diode 98 and the diode 100, and the point f that is the connection point between the diode and the capacitor 101 are all 0V.

  Next, in the section T1, the oscillation circuit 91 outputs the ground voltage (0 V). As a result, 3 V obtained by inverting 0 V output from the oscillation circuit 91 by the inverting logic circuit 92 is input to the drive circuit 93, and the output (point a) becomes 0 V. Since 0V is input to the drive circuit 94 and the drive circuit 95, the output (point b) of the drive circuit 94 and the output (point c) of the drive circuit 95 are 3V. In this state, current flows from the drive circuit 94 to the capacitor 96 via the diode 97, and the capacitor 96 is charged. As a result, the voltage at the point d becomes 3V. As a result, the voltage at point e and point f is also 3V.

  Next, in the section T2, the oscillation circuit 91 outputs the battery voltage (3V). As a result, the output (point a) of the drive circuit 93 becomes 3V, and the output (point b) of the drive circuit 94 and the output (point c) of the drive circuit 95 become 0V. At this time, the voltage at the point d is boosted to a voltage (6 V) that is twice the battery voltage. The boosted voltage is applied to the capacitor 99 via the diode 98 to charge the capacitor 99. As a result, the voltage at the point e becomes 6V. Further, the boosted voltage is applied to the capacitor 101 via the diode 98 and the diode 100 to charge the capacitor 101. As a result, the voltage at point f is also 6V.

  Next, in the section T3, the oscillation circuit 91 outputs the ground voltage (0 V). As a result, the output (point a) of the drive circuit 93 becomes 0V, and the output (point b) of the drive circuit 94 and the output (point c) of the drive circuit 95 become 3V. At this time, the voltage at the point d is 3V, but the voltage at the point e is boosted to 3 times the battery voltage (9V) by superimposing the battery voltage 3V on the voltage (6V) of the capacitor 99. The boosted voltage is supplied to the capacitor 101 via the diode 100 and charges the capacitor 101. As a result, the voltage at the point f becomes 9V, which is three times the battery voltage. Thereafter, by repeating the above-described operation, the 3V battery voltage input to the first booster circuit 90a is boosted to a voltage of 9V, which is three times, and output.

  FIG. 6 is a circuit diagram showing a detailed configuration of the second booster circuit 90b shown in FIG. The second booster circuit 90b is a booster circuit adopting a charge pump system, and includes an oscillation circuit 91, an inverting logic circuit 92, a drive circuit 93, a drive circuit 94, a capacitor 96, a diode 97, a diode 100, and a capacitor 101. Yes.

  The configurations of the oscillation circuit 91, the inverting logic circuit 92, the drive circuit 93, and the drive circuit 94 are the same as those shown in FIG. The other end of the capacitor 96 is connected to the anode of the diode 100. The cathode of the diode 97 is connected to the connection point between the other end of the capacitor 96 and the anode of the diode 100. The cathode of the diode 100 is connected to one end of the capacitor 101, and the other end of the capacitor 101 is grounded. The voltage at one end of the capacitor 101 is sent to the second voltage stabilizing circuit 110b as the output of the second booster circuit 90b.

  Next, the operation of the second booster circuit 90b configured as described above will be described. In the section where the oscillation circuit 91 outputs the ground voltage (0V), the drive circuit 94 outputs the battery voltage (3V). The drive circuit 93 outputs 0 V because the battery voltage obtained by inverting the ground voltage output from the oscillation circuit 91 by the inverting logic circuit 92 is input. As a result, current flows from the drive circuit 94 to the capacitor 96 via the diode 97, and the capacitor 96 is charged. As a result, the voltage at the connection point between the capacitor 96 and the diode 100 becomes 3V of the battery voltage.

  Next, when the oscillation circuit 91 enters a section in which the battery voltage is output, the drive circuit 94 outputs a ground voltage. Further, the drive circuit 93 outputs the battery voltage because the ground voltage obtained by inverting the battery voltage output from the oscillation circuit 91 by the inverting logic circuit 92 is input. At this time, the voltage at the connection point between the capacitor 96 and the diode 100 is boosted to twice the battery voltage. The boosted voltage is supplied to the capacitor 101 via the diode 100 and charges the capacitor 101. In this way, the battery voltage input to the second booster circuit 90b is boosted to a voltage twice and output.

  FIG. 7 is a circuit diagram showing a detailed configuration of the third booster circuit 90c shown in FIG. The third booster circuit 90c is a booster circuit that employs a charge pump system, and is configured by adding a voltage conversion circuit 102 to the first booster circuit 90a described above. The voltage conversion circuit 102 includes a resistor 103, a resistor 104, a capacitor 105, and a capacitor 106. The resistor 103 and the resistor 104 are connected in series between the positive electrode of the battery 70 and the ground, and the capacitor 105 and the capacitor 106 are connected in parallel to the resistor 103 and the resistor 104, respectively. The voltage conversion circuit 102 converts the input battery voltage (3V) into half 1.5V by resistance division by the resistor 103 and the resistor 104, and outputs it. When the voltage of 1.5V output from the voltage conversion circuit 102 is input to a circuit corresponding to the first booster circuit 90a described above, the voltage is boosted to three times (4.5V) and output.

  FIG. 8 is a circuit diagram showing a detailed configuration of the first voltage stabilization circuit 110a, the second voltage stabilization circuit 110b, and the third voltage stabilization circuit 110c shown in FIG. Each of these circuits has the same configuration except for the resistance value of the resistor used (details will be described later), and therefore will be described below as the voltage stabilization circuit 110. The voltage stabilization circuit 110 includes an operational amplifier circuit 111, a reference voltage source 112, a resistor 113, a resistor 114, a transistor 115, and a capacitor 116.

  The resistor 113 and the resistor 114 are connected in series between the power supply line and the ground. The inverting input terminal (−) of the operational amplifier circuit 111 is connected to the reference voltage source 112, and the non-inverting input terminal (+) is connected to a connection point between the resistor 113 and the resistor 114. The output terminal of the operational amplifier circuit 111 is connected to the base of the transistor 115.

  The emitter of the transistor 115 is connected to the output of the previous booster circuit (the first booster circuit 90a, the second booster circuit 90b, or the third booster circuit 90c), and the collector is connected to the power supply line. A capacitor 116 is provided between the power supply line and the ground, and the voltage of the capacitor 116 is output to the power supply line connected to the transmission circuit 23, the reception circuit 25, or the display unit 60.

  Next, the operation of the voltage stabilization circuit 110 configured as described above will be described. Since the voltage of the capacitor 116 is 0 V when the power is turned on, the voltage applied to the inverting input terminal (−) is larger than the voltage applied to the non-inverting input terminal (+) of the operational amplifier circuit 111. Therefore, since the output of the operational amplifier circuit 111 is 0 V, current is drawn from the base of the transistor 115. As a result, the transistor 115 is turned on, and current flows from the emitter to the collector. The current flowing out from the collector of the transistor charges the capacitor 116 through the power supply line, and the voltage rises.

  At this time, the voltage of the capacitor 116 is divided by the resistor 113 and the resistor 114 and applied to the non-inverting input terminal (+) of the operational amplifier circuit 111. When the voltage applied to the non-inverting input terminal (+) becomes larger than the voltage output from the reference voltage source 112, the voltage output from the operational amplifier circuit 111 becomes high level (hereinafter referred to as “H level”). The base current of the transistor 115 does not flow. As a result, transistor 115 is turned off and no current flows from its emitter to its collector. In this state, when the charge charged in the capacitor 116 is consumed by the transmission circuit 23, the reception circuit 25, or the display unit 60 and the voltage drops, the voltage applied to the non-inverting input terminal (+) of the operational amplifier circuit 111 is lower. The voltage input to the inverting input terminal (−) increases, and the above operation is repeated again. In this way, the output voltage of the voltage stabilization circuit 110 is stabilized.

  At this time, the output voltage of the voltage stabilizing circuit 110 is determined by the voltage dividing ratio of resistance division by the resistors 113 and 114. The voltage dividing ratio is such that the output of the first voltage stabilizing circuit 110a is 6V, which is the lowest operating voltage of the transmitting circuit 23, and the output of the second voltage stabilizing circuit 110b is 4V, which is the lowest operating voltage of the receiving circuit 25. The output of the third voltage stabilizing circuit 110c is adjusted so as to be 3V, which is the minimum operating voltage of the display unit 60.

  Further, as described above, the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c are configured so that each of the transmitter circuit 23, the receiver circuit 25, and the display unit 60 can be used even when the battery 70 is exhausted. The voltage is boosted to output a voltage higher than the minimum operating voltage. That is, the output voltage of the battery 70 changes from 3V to 2V, the minimum operating voltage of the transmission circuit 23 is 6V, the minimum operating voltage of the receiving circuit 25 is 4V, and the minimum operating voltage of the display unit 60 is 3V. The first booster circuit 90a connected to 23 performs a boost of 6V / 2V = 3 times. Similarly, the second booster circuit 90b connected to the receiving circuit 25 performs boosting of 4V / 2V = 2 times, and the third booster circuit 90c connected to the display unit 60 is 3V / 2V = 1.5 times. Is boosted. When the battery 70 is in the initial use state and the output voltage is as high as 3V, the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c are 9V, 6V, and 4.5V, respectively. Output.

  In the conventional ultrasonic gas meter, since a voltage of 9V to 6V is supplied to the transmission circuit 23, a performance change of 9V-6V = 3V appears. Similarly, a performance change of 6V-4V = 2V appears in the receiving circuit 25, and a performance change of 4.5V-3V = 1.5V appears in the display unit 60, respectively. On the other hand, in the ultrasonic gas meter according to the first embodiment of the present invention, the voltage supplied to the transmission circuit 23, the reception circuit 25, and the display unit 60 is the lowest operating voltage by providing the voltage stabilization circuit 110. The operation performance of each circuit becomes stable.

  As described above, according to the ultrasonic gas meter according to the first embodiment of the present invention, the transmission circuit 23, the reception circuit 25, and the display unit 60 include the first voltage stabilization circuit 110a and the second voltage stabilization circuit 110b. Since the minimum operating voltage is supplied from the third voltage stabilization circuit 110c, the characteristics of the transmission circuit 23, the reception circuit 25, and the display unit 60 do not change even if the output voltage of the battery 70 fluctuates. Therefore, since the acoustic output of the ultrasonic wave transmitted by the transmission circuit 23 is constant, there is no need to consider fluctuation due to voltage. In the receiving circuit 25, the performance of the built-in amplifier circuit and detection circuit is stabilized, so that fluctuations in measurement results are reduced and current consumption is also reduced. Further, in the display unit 60, the contrast of turning off / on of the display does not change and it is easy to see.

  FIG. 9 is a block diagram illustrating a power supply system of the ultrasonic gas meter according to the second embodiment of the present invention. The power supply system of the ultrasonic gas meter is configured by adding a delay circuit 120, a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4 to the power supply system of the ultrasonic gas meter according to the first embodiment. ing. The first switch S1 and the second switch S2 are called input side switches, and the third switch S3 and the fourth switch S4 are called output side switches. The control circuit 10 has a function of outputting an operation start signal for causing the transmission circuit 23 and the reception circuit 25 to operate intermittently.

  The control circuit 10 sends an operation start signal to the first switch S1 and the second switch and the delay circuit 120. The delay circuit 120 delays the operation start signal sent from the control circuit 10 by a set time and sends it to the third switch S3 and the fourth switch S4. As a result, after the outputs of the first booster circuit 90a, the second booster circuit 90b, the first voltage stabilizer circuit 110a, and the second voltage stabilizer circuit 110b are stabilized, power is supplied to the transmitter circuit 23 and the receiver circuit 25. It is controlled so that Details of the delay circuit 120 will be described later.

  The first switch S1 opens and closes in response to an operation start signal from the control circuit 10, and controls whether or not to send the output of the battery 70 to the first booster circuit 90a. The second switch S2 opens and closes in response to an operation start signal from the control circuit 10, and controls whether or not to send the output of the battery 70 to the second booster circuit 90b. The third switch S3 controls whether the output of the first voltage stabilization circuit 110a is sent to the transmission circuit 23 according to the power supply switch control signal from the delay circuit 120. The fourth switch S4 controls whether or not to send the output of the second voltage stabilization circuit 110b to the reception circuit 25 in accordance with the power supply switch control signal from the delay circuit 120.

  FIG. 10 is a circuit diagram showing a detailed configuration of delay circuit 120 shown in FIG. 9 and its periphery. The delay circuit 120 includes an AND circuit 121, an AND circuit 122, an AND circuit 123, a resistor 124, a resistor 125, a resistor 126, a capacitor 127, a reference voltage source 128, and a comparator 129.

  An operation start signal from the control circuit 10 is input to one input terminal of the AND circuit 121, and a setting signal from the control circuit 10 is input to the other input terminal. This setting signal is a signal for setting whether to make the logical product circuit 121 active. The output of the AND circuit 121 is connected to one terminal of the capacitor 127 and the non-inverting input terminal (+) of the comparator 129 via the resistor 124.

  An operation start signal from the control circuit 10 is input to one input terminal of the AND circuit 122, and a setting signal from the control circuit 10 is input to the other input terminal. This setting signal is a signal for setting whether to make the logical product circuit 122 active. The output of the AND circuit 122 is connected to one terminal of the capacitor 127 and the non-inverting input terminal (+) of the comparator 129 via the resistor 125.

  An operation start signal from the control circuit 10 is input to one input terminal of the AND circuit 123, and a setting signal from the control circuit 10 is input to the other input terminal. This setting signal is a signal for setting whether to make the logical product circuit 123 active. The output of the AND circuit 123 is connected to one terminal of the capacitor 127 and the non-inverting input terminal (+) of the comparator 129 via the resistor 125.

  The other terminal of the capacitor 127 is grounded, and the reference voltage is applied from the reference voltage source 128 to the inverting input terminal (−) of the comparator 129. The comparator 129 compares the voltage of the capacitor 127 with the reference voltage from the reference voltage source 128. As a result of the comparison, the power supply switch control signal of H level or L level (hereinafter referred to as “L level”) is switched to the third switch. S3 and the fourth switch S4. Opening and closing of the third switch S3 and the fourth switch S4 is controlled by the power supply switch control signal.

  Next, the operation of the delay circuit 120 configured as described above will be described. When the operation start signal sent from the control circuit 10 becomes H level, the AND circuit 121 receives an H level setting signal from the control circuit 10 to the other input terminal, so that its output becomes H level. Thus, a current flows through the resistor 124 and charging of the capacitor 127 is started. In addition, when the H level setting signal is input to the other input terminal from the control circuit 10, the output of the AND circuit 122 becomes the H level, and a current flows through the resistor 125 to charge the capacitor 127. To start. Further, when the H level setting signal is input from the control circuit 10 to the other input terminal of the logical product circuit 123, the output becomes the H level, and a current flows through the resistor 126 to charge the capacitor 127. To start.

  The voltage of the capacitor 127 increases according to a time constant determined by the resistance values of the resistor 124, the resistor 125, and the resistor 126 and the capacitance value of the capacitor 127. When the voltage of the capacitor 127 becomes larger than the reference voltage applied from the reference voltage source 128, the comparator 129 outputs an H level power supply switch control signal and sends it to the third switch S3 and the fourth switch S4. As a result, the third switch S3 and the fourth switch S4 are turned on, and power is supplied from the first voltage stabilization circuit 110a and the second voltage stabilization circuit 110b to the transmission circuit 23 and the reception circuit 25, respectively.

  The comparator 129 sends an L level power supply switch control signal to the third switch S3 and the fourth switch S4 when the voltage of the capacitor 127 becomes lower than the reference voltage. As a result, the third switch S3 and the fourth switch S4 are turned off, and the supply of power to the transmission circuit 23 and the reception circuit 25 is interrupted.

  With the above configuration, when the operation start signal is output from the control circuit 10, the first switch S1 and the second switch S2 are turned on, and the first boost circuit 90a, the second boost circuit 90b, and the first voltage stabilization. The circuit 110a and the second voltage stabilization circuit 110b start to operate, and after the electric charge is sufficiently accumulated in the capacitor 127 of the delay circuit 120, power is supplied to the transmission circuit 23 and the reception circuit 25.

  As the number of ultrasonic measurements increases, the power required by the transmission circuit 23 and the reception circuit 25 increases. Therefore, power is supplied to the transmission circuit 23 and the reception circuit 25 after the outputs of the first boost circuit 90a, the second boost circuit 90b, the first voltage stabilization circuit 110a, and the second voltage stabilization circuit 110b are sufficiently stabilized. There is a need.

  However, when the number of ultrasonic measurements is small, the transmission circuit 23 and the reception circuit 25 do not require large power, and the time for supplying power to the transmission circuit 23 and the reception circuit 25 can be shortened. Therefore, the control circuit 10 can suppress unnecessary current consumption by sending a setting signal corresponding to the number of ultrasonic measurements to the delay circuit 120. As a result, consumption of the battery 70 can be suppressed and the life of the ultrasonic gas meter can be extended.

  As described above, according to the ultrasonic gas meter according to the second embodiment of the present invention, the transmission circuit 23 and the reception circuit 25 change the power consumption depending on the number of ultrasonic measurements. By setting the delay time long and setting the delay time short when the power consumption is low, the battery consumption can be further suppressed.

  Instead of providing the delay circuit 120, the control circuit 10 can be configured to generate a power supply switch control signal for controlling the opening and closing of the third switch S3 and the fourth switch S4.

  FIG. 11 is a flowchart showing processing performed by the control circuit 10 when the control circuit 10 generates a power supply switch control signal. First, the control circuit 10 calculates the next ultrasonic measurement count time and sets the loop count n (step ST11). Next, the control circuit 10 sends an operation start signal to the first switch S1 and the second switch S2 (step ST12). As a result, the first booster circuit 90a, the second booster circuit 90b, the first voltage stabilization circuit 110a, and the second voltage stabilization circuit 110b start operation.

  Next, the control circuit 10 checks whether or not the loop count n is zero (step ST13). If it is determined that it is not zero, the loop count is decremented (-1) (step ST14) and the process returns to step ST13. On the other hand, when the control circuit 10 determines that it is zero in step ST13, it sends a power supply switch control signal to the third switch S3 and the fourth switch S4 (step ST15). As a result, the third switch S3 and the fourth switch S4 are turned on, and power is supplied to the transmission circuit 23 and the reception circuit 25.

  FIG. 12 is a block diagram showing a power supply system of an ultrasonic gas meter according to Embodiment 3 of the present invention. The power supply system for the ultrasonic gas meter is configured by adding a low voltage stabilization circuit 130 between the battery 70 and the control circuit 10 in the power supply system for the ultrasonic gas meter according to the first embodiment. The low voltage stabilization circuit 130 converts the voltage from the battery 70 to be the lowest operating voltage of the control circuit 10, stabilizes it, and supplies it to the control circuit 10.

  FIG. 13 is a circuit diagram showing a detailed configuration of the low voltage stabilization circuit 130 shown in FIG. 12 and its periphery. This low voltage stabilization circuit 130 is the same as that of the first embodiment except that the voltage dividing ratio of the resistor 113 and the resistor 114 is adjusted so that the voltage of the capacitor 116 becomes the minimum operating voltage of the control circuit 10. The configuration and operation of the voltage stabilizing circuit 110 shown in FIG.

  Now, let the minimum operating voltage of the control circuit 10 be 2V. In the conventional ultrasonic gas meter, when the voltage of the battery 70 is 3V, which is the initial operating voltage, a voltage of 3V is applied to the control circuit 10, so that a large amount of current is consumed there. On the other hand, in the case of the ultrasonic gas meter according to the third embodiment, even when the voltage of the battery 70 is 3V, the voltage applied to the control circuit 10 is 2V, which is the minimum operating voltage. The current consumed is small. As a result, consumption of the battery 70 can be suppressed and the life of the ultrasonic gas meter can be extended.

  The ultrasonic gas meter according to the third embodiment is configured to add the low voltage stabilization circuit 130 between the battery 70 and the control circuit 10 in the power supply system of the ultrasonic gas meter according to the first embodiment. In the power supply system of the ultrasonic gas meter according to the second embodiment, a low voltage stabilization circuit 130 may be added between the battery 70 and the control circuit 10.

  FIG. 14 is a block diagram showing a power supply system of an ultrasonic gas meter according to Embodiment 4 of the present invention. In this ultrasonic gas meter power supply system, the first voltage stabilization circuit 110a, the second voltage stabilization circuit 110b, and the third voltage stabilization circuit 110c are removed from the power supply system of the ultrasonic gas meter according to the first embodiment. A low voltage stabilization circuit 130 is added between the battery 70, the control circuit 10, the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c. The low voltage stabilization circuit 130 is the same as that used in the ultrasonic gas meter according to the third embodiment.

  The output voltage from the battery 70 is stabilized by the low voltage stabilization circuit 130 and then supplied to the control circuit 10, the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c. The power boosted in the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c is supplied to the transmitter circuit 23, the receiver circuit, and the display unit 60, respectively.

  Assume that the voltage of the battery 70 changes from 3V to 2V, the minimum operating voltage of the control circuit 10 is 2V, the minimum operating voltage of the transmitting circuit 23 is 6V, the minimum operating voltage of the receiving circuit 25 is 4V, and the display unit 60. The minimum operating voltage is 3V. In this case, the output of the low voltage stabilization circuit 130 becomes 2V, and the first booster circuit 90a connected to the transmission circuit 23 performs a boost of 6V / 2V = 3 times and the second booster circuit connected to the reception circuit 25. The circuit 90b boosts 4V / 2V = 2 times, and the third booster circuit 90c connected to the display unit 60 boosts 3V / 2V = 1.5 times.

  As described above, the low voltage stabilization circuit 130 is inserted between the battery 70 and the control circuit 10, the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c. The voltages supplied to the receiving circuit and the display unit 60 are constant at the minimum operating voltage, and the operating performance is stable.

  As described above, according to the ultrasonic gas meter according to the fourth embodiment of the present invention, the first voltage stabilizing circuit 110a, the second voltage stabilizing circuit 110b, and the third voltage stabilizing in the ultrasonic gas meter according to the first embodiment. Since the circuit 110c becomes unnecessary, the performance of the transmission circuit 23, the reception circuit 25, and the display unit 60 can be stabilized and current consumption can be suppressed with a small circuit configuration. Thereby, consumption of the battery 70 can be suppressed and the life of the ultrasonic gas meter can be extended.

  Note that the power supply system of the ultrasonic gas meter according to the fourth embodiment is different from the power supply system of the ultrasonic gas meter according to the first embodiment in the first voltage stabilizing circuit 110a, the second voltage stabilizing circuit 110b, and the third voltage stabilizing circuit 110c. The low voltage stabilization circuit 130 is added between the battery 70 and the control circuit 10, the first booster circuit 90a, the second booster circuit 90b, and the third booster circuit 90c. The first voltage stabilizing circuit 110a, the second voltage stabilizing circuit 110b, and the third voltage stabilizing circuit 110c are removed from the power supply system of the ultrasonic gas meter according to Example 2, and the battery 70, the control circuit 10, and the first boosting circuit are removed. A low voltage stabilizing circuit 130 may be additionally provided between 90a, the second booster circuit 90b, and the third booster circuit 90c.

  FIG. 15 is a block diagram showing a power supply system of an ultrasonic gas meter according to Embodiment 5 of the present invention. In this ultrasonic gas meter power supply system, the first voltage stabilization circuit 110a, the second voltage stabilization circuit 110b, and the third voltage stabilization circuit 110c are removed from the power supply system of the ultrasonic gas meter according to the first embodiment. A low voltage stabilizing circuit 130 is added between the battery 70 and the control circuit 10, the first booster circuit 90a and the second booster circuit 90b, and a low current and low voltage is provided between the battery 70 and the third booster circuit 90c. A circuit 140 and a clock circuit 150 are added to the configuration. The clock circuit 150 is connected to the output of the low current low voltage circuit 140. The low current low voltage circuit 140 steps down the output voltage of the battery 70 and supplies it to the third boost circuit 90 c and the clock circuit 150.

  FIG. 16 is a circuit diagram showing a detailed configuration of the low-current low-voltage circuit 140 shown in FIG. 15 and its surroundings. The low current low voltage circuit 140 includes a resistor 141 and a capacitor 142. The clock circuit 150 includes an oscillation circuit and a timer circuit (not shown), and has a clock function and a timer function.

  Although the control circuit 10, the transmission circuit 23, and the reception circuit 25 have relatively large operating currents, the display unit 60 and the clock circuit 150 are required to always operate, so that they are configured to operate with a minimum current. Therefore, the ultrasonic gas meter according to the fifth embodiment is configured to extract a large amount of output current from the low voltage stabilization circuit 130 and to extract a small amount of output current from the low current and voltage reduction circuit 140.

  The low-current and low-voltage circuit 140 smoothes the current from the battery 70 with the capacitor 142 and takes it out almost as a direct current. At this time, since the resistor 141 is inserted, a voltage drop occurs, and the voltage applied to the third booster circuit 90c and the clock circuit 150 is reduced.

  Since the voltage drop of the battery 70 is mainly caused by an increase in its internal resistance, the voltage drop is large when the current consumption on the circuit side is large, but the voltage drop when the current consumption on the circuit side is minimal. Is small. For this reason, the voltage drop in the third booster circuit 90c and the clock circuit 150 is small. Further, even if the voltage drop of the battery 70 occurs due to the operation of the control circuit 10, the transmission circuit 23, and the reception circuit 25 due to the capacity of the capacitor 142, the time required for ultrasonic measurement is short, so that the third The voltage drop in the booster circuit 90c and the clock circuit 150 is small. For this reason, since the low-voltage stabilization circuit 130 is not operated at all times, the overall current consumption can be reduced. As a result, consumption of the battery 70 can be suppressed and the life of the meter can be extended.

  Note that the power supply system of the ultrasonic gas meter according to the fifth embodiment is different from the power supply system of the ultrasonic gas meter according to the first embodiment in the first voltage stabilizing circuit 110a, the second voltage stabilizing circuit 110b, and the third voltage stabilizing circuit 110c. And a low voltage stabilizing circuit 130 is added between the battery 70 and the control circuit 10, the first booster circuit 90a and the second booster circuit 90b, and further between the battery 70 and the third booster circuit 90c. In addition, a low-current low-voltage circuit 140 and a clock circuit 150 are added to the first power stabilization circuit 110a, the second voltage stabilization circuit 110b, and the power supply system of the ultrasonic gas meter according to the second embodiment. The third voltage stabilization circuit 110c is removed, and a low voltage stabilization circuit is provided between the battery 70, the control circuit 10, the first booster circuit 90a, and the second booster circuit 90b. 30 was added and further, can be configured by adding a low-current low-voltage circuit 140 and a clock circuit 150 between the battery 70 and the third booster circuit 90c.

  The ultrasonic gas meter according to the present invention can be used as a flow meter for measuring the flow rate of a fluid such as a water meter in addition to the gas meter.

It is a figure which shows the structure of the ultrasonic gas meter which concerns on Example 1 of this invention. It is a block diagram which shows the electric constitution of the gas meter which concerns on Example 1 of this invention. It is a block diagram which shows the power supply system of the ultrasonic gas meter which concerns on Example 1 of this invention. FIG. 4 is a circuit diagram showing a detailed configuration of a first booster circuit shown in FIG. 3. FIG. 4 is a diagram for explaining the operation of the first booster circuit shown in FIG. 3. FIG. 4 is a circuit diagram showing a detailed configuration of a second booster circuit shown in FIG. 3. FIG. 4 is a circuit diagram showing a detailed configuration of a third booster circuit shown in FIG. 3. FIG. 4 is a circuit diagram showing a detailed configuration of a first voltage stabilization circuit, a second voltage stabilization circuit, and a third voltage stabilization circuit shown in FIG. 3. It is a block diagram which shows the power supply system of the ultrasonic gas meter which concerns on Example 2 of this invention. FIG. 10 is a circuit diagram showing a detailed configuration of the delay circuit shown in FIG. 9 and its periphery. FIG. 10 is a flowchart showing processing when a power supply switch control signal is generated by a control circuit instead of the delay circuit shown in FIG. 9. FIG. It is a block diagram which shows the power supply system of the ultrasonic gas meter which concerns on Example 3 of this invention. FIG. 13 is a circuit diagram showing a detailed configuration of the low voltage stabilization circuit shown in FIG. 12 and its periphery. It is a block diagram which shows the power supply system of the ultrasonic gas meter which concerns on Example 4 of this invention. It is a block diagram which shows the power supply system of the ultrasonic gas meter which concerns on Example 5 of this invention. FIG. 16 is a circuit diagram showing a detailed configuration of a low current low voltage circuit shown in FIG. 15 and its periphery. It is a figure which shows the structure of the power supply system of the conventional ultrasonic gas meter.

Explanation of symbols

10 control circuit 23 transmission circuit 25 reception circuit 50 shutoff valve 60 display unit 70 battery 90a first boost circuit 90b second boost circuit 90c third boost circuit 110a first voltage stabilization circuit 110b second voltage stabilization circuit 110a third voltage Stabilization circuit 120 Delay circuit 130 Low voltage stabilization circuit 140 Low current low voltage circuit 150 Clock circuit S1, S2, S3, S4 switch

Claims (6)

A transmission circuit for generating an ultrasonic wave by sending a transmission signal to one of the pair of ultrasonic sensors arranged in the gas flow path;
A receiving circuit for detecting a reception signal from the other ultrasonic sensor that has received the ultrasonic wave generated by the one ultrasonic sensor;
The ultrasonic propagation time is measured by measuring the time from when the transmission signal is output by the transmission circuit until the reception signal is detected by the reception circuit, and the gas is measured based on the measured ultrasonic propagation time. A control circuit for calculating the flow rate of
A display for displaying the flow rate of the gas calculated by the control circuit;
A battery for supplying power to the control circuit;
A booster circuit for boosting the output voltage of the battery;
The output voltage of the booster circuit is stabilized to the minimum operating voltage of the transmission circuit, the reception circuit, and the display unit, and the stabilized voltage is supplied to the transmission circuit, the reception circuit, and the display unit as a power source. A voltage stabilization circuit;
An ultrasonic gas meter comprising: A transmission circuit for generating an ultrasonic wave by sending a transmission signal to one of the pair of ultrasonic sensors arranged in the gas flow path;
A receiving circuit for detecting a reception signal from the other ultrasonic sensor that has received the ultrasonic wave generated by the one ultrasonic sensor;
The ultrasonic propagation time is measured by measuring the time from when the transmission signal is output by the transmission circuit until the reception signal is detected by the reception circuit, and the gas is measured based on the measured ultrasonic propagation time. A control circuit for calculating the flow rate of
A display for displaying the flow rate of the gas calculated by the control circuit;
A battery for supplying power to the control circuit;
An input side switch that opens and closes in response to an operation start signal intermittently output from the control circuit;
A booster circuit for boosting a voltage sent from the battery via the input side switch;
A voltage stabilizing circuit that stabilizes the output voltage of the booster circuit to the minimum operating voltage of the transmitting circuit, the receiving circuit, and the display unit;
A delay circuit that intermittently outputs an operation start signal output from the control circuit in accordance with a time during which the transmission circuit and the reception circuit are operated, and outputs a power supply switch control signal;
An output-side switch for controlling whether to supply the output of the voltage stabilization circuit to the transmission circuit and the reception circuit as a power source by opening and closing according to a power supply switch control signal from the delay circuit;
An ultrasonic gas meter comprising:   2. The ultrasonic gas meter according to claim 1, further comprising a low voltage stabilization circuit that stabilizes an output voltage of the battery and sends the stabilized voltage to the control circuit as a power source. A transmission circuit for generating an ultrasonic wave by sending a transmission signal to one of the pair of ultrasonic sensors arranged in the gas flow path;
A receiving circuit for detecting a reception signal from the other ultrasonic sensor that has received the ultrasonic wave generated by the one ultrasonic sensor;
The ultrasonic propagation time is measured by measuring the time from when the transmission signal is output by the transmission circuit until the reception signal is detected by the reception circuit, and the gas is measured based on the measured ultrasonic propagation time. A control circuit for calculating the flow rate of
A display for displaying the flow rate of the gas calculated by the control circuit;
A battery for supplying power to the control circuit;
A low voltage stabilization circuit for stabilizing the output voltage of the battery;
A boosting circuit that boosts the voltage stabilized by the low voltage stabilization circuit and supplies the boosted voltage to the transmission circuit, the reception circuit, and the display unit as a power source;
An ultrasonic gas meter comprising: A transmission circuit for generating an ultrasonic wave by sending a transmission signal to one of the pair of ultrasonic sensors arranged in the gas flow path;
A receiving circuit for detecting a reception signal from the other ultrasonic sensor that has received the ultrasonic wave generated by the one ultrasonic sensor;
The ultrasonic propagation time is measured by measuring the time from when the transmission signal is output by the transmission circuit until the reception signal is detected by the reception circuit, and the gas is measured based on the measured ultrasonic propagation time. A control circuit for calculating the flow rate of
A display for displaying the flow rate of the gas calculated by the control circuit;
A battery for supplying power to the control circuit;
A low voltage stabilization circuit for stabilizing the output voltage of the battery;
A step-up circuit that boosts the voltage stabilized by the low-voltage stabilization circuit and supplies the boosted voltage to the transmission circuit and the reception circuit as a power source;
A low-current low-voltage circuit for reducing the output of the battery to a low current and a low voltage;
Another booster circuit that supplies the display unit with the current and voltage that have been reduced in the low-current and low-voltage circuit as a power source, and
An ultrasonic gas meter comprising: An input side switch that is provided on the input side of the booster circuit and opens and closes in response to an operation start signal intermittently output from the control circuit;
A delay circuit that intermittently outputs an operation start signal output from the control circuit in accordance with a time during which the transmission circuit and the reception circuit are operated, and outputs a power supply switch control signal;
An output-side switch that controls whether to supply power to the transmission circuit and the reception circuit by opening and closing according to a power supply switch control signal from the delay circuit;
The ultrasonic gas meter according to any one of claims 3 to 5, further comprising:

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