JP2005249642A - Flow measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform stable power supply with the same voltage by using an ordinary measuring power source as a power source for ultrasonic driving, and to realize operation not exerting an influence of a noise or the like on a system, by solving the problems wherein operation timing is not unified, and, if a booster circuit is operated when performing initial setting operation or the like of a circuit, a system voltage is fluctuated, in the case of using a DCDC converter. <P>SOLUTION: A control device 45 controls the whole operation of a measuring system by a voltage lowered by a voltage stabilizing means 43 from the power source 42, and controls power supply to an oscillator 32 transmitting an ultrasonic wave by using the same voltage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flow measurement device that measures the flow rate of gas or liquid using ultrasonic waves.

  Conventionally, this type of flow measuring device uses a DCDC converter as means for using a high voltage to output ultrasonic waves (see, for example, Patent Document 1). FIG. 13 is a block diagram showing a configuration of a general booster circuit. As shown in FIG. 13, the power source 1, the DCDC converter 2, the inductance L <b> 3, the diode D <b> 4, the capacitor C <b> 5, and the load 6 are included. In the DC-DC converter 2, the back electromotive force generated in the inductance is rectified through the diode 4 when the inductance 3 is switched from on to off by switching the inductance 3, and a stable high voltage in which the ripple is reduced by the capacitor 5 is applied to the load 6. To supply. FIG. 14 is a block diagram showing a configuration of a conventional ultrasonic flowmeter (see, for example, Patent Document 1).

  In FIG. 14, a first vibrator 12 that transmits ultrasonic waves and a second vibrator 13 that receives ultrasonic waves are disposed in the flow direction in the middle of the fluid flow path 11. Reference numeral 14 denotes a transmission circuit to the first vibrator 12, and 15 denotes a reception circuit that performs signal processing on the ultrasonic waves received by the second vibrator 13. Reference numeral 16 denotes a repeating unit that repeats transmission from the first vibrator 12 and reception by the second vibrator 13 after the ultrasonic wave is detected by the receiving circuit 15.

  Reference numeral 17 denotes delay time generating means for generating a delay time until ultrasonic waves are transmitted again from the first transducer 12 after detecting the ultrasonic wave by the receiving circuit. Reference numeral 18 denotes delay time generated by the delay time generating means 17. Is a delay time measuring means for measuring the delay time, 19 is a delay time control means for controlling the delay time based on the measured value of the delay time generating means 17, and 20 is a time required for plural times of ultrasonic transmission performed by the repeating means. An accumulated time measuring means 21 for measuring, a flow rate calculating means for obtaining a flow rate from the measured values of the delay time measuring means 18 and the accumulated time measuring means 20.

  The ultrasonic signal transmitted from the first transducer 12 by the burst signal transmitted from the transmission circuit 14 propagates in the flow, is received by the second transducer 13 and detected by the reception circuit 15, and delay time generating means After the delay time generated at 17 is set, the burst signal is transmitted from the transmission circuit 14 again. The burst signal from the transmission circuit 14 is repeated a predetermined number of times, and the time required for this repetition is measured by the accumulated time measuring means 20 and the delay time is measured by the delay time measuring means 10.

Further, the flow rate calculating means 21 obtains the required time T for only transmitting ultrasonic waves by subtracting the delay time obtained by the delay time measuring means 19 from the value obtained by the accumulated time measuring means 20. Normally, when driving the vibrator from this transmission circuit, a high voltage is supplied in consideration of the signal attenuation due to the propagation distance. As the circuit, the booster circuit described above is often used.
JP 2000-292232 A (2nd page, FIG. 1)

  However, in the conventional high voltage supply circuit in the booster circuit, the operation timing of the DCDC converter considering the operation of the load and the stability of the entire circuit is not unified, and operates individually. For example, if the operation of the DCDC converter is started before the supply voltage to the transmission / reception circuit is stabilized, there is a possibility that waste will occur in the time after the charging until the load operates. Furthermore, if the booster circuit operates during the initial setting operation of the circuit, the system voltage may fluctuate or the measurement accuracy may be degraded due to noise. Further, the voltage conversion efficiency of the DCDC converter is not so high, and there is a problem that the measurement system that requires power saving has a difficulty in use.

  The present invention solves the above-described conventional problem, and does not install a separate power source for driving ultrasonic waves, but uses a common power source for control circuits, and the voltage difference between the measurement system and the ultrasonic oscillation system is determined. An object of the present invention is to realize an accurate flow rate measurement that performs a stable operation of a measurement system by performing stable power supply in a state of being eliminated and performing an operation that does not affect the system such as noise.

  In order to solve the above-mentioned conventional problems, the control means of the flow measurement device of the present invention controls the overall operation of the measurement system with a stable voltage stepped down from the power supply and also supplies power to the transducer that transmits ultrasonic waves. It is shared and controlled.

  The control means in the flow measuring device of the present invention controls the overall operation of the measurement system by the voltage stepped down from the power supply, and also controls the power supply to the transducer transmitting ultrasonic waves using the same stable voltage. It is. This makes it possible to realize accurate flow measurement that realizes stable operation of the measurement system by suppressing the instability of voltage and switching noise caused by operations such as boosting, and the system without reducing power conversion efficiency The action can be performed.

  A first invention is a pair of transducers arranged in a flow path through which a fluid to be measured flows and transmits / receives ultrasonic waves, a transmission unit that drives the transducers, and a reception unit that converts an output signal of a reception-side transducer into an electrical signal A transmission / reception switching unit of the transducer, a repeating unit that performs ultrasonic propagation between the transducers a plurality of times, a delay unit that delays a transmission signal from the transducer during the repetition, and a plurality of repetitions of each A time measuring means for measuring the propagation time, a flow rate calculating means for calculating a flow rate based on a difference between respective time measured values by the time measuring means, a power source, a power source stabilizing means for generating a lower voltage than the power source, and a control means. And the control means includes a power supply control means for controlling the transmission means by the output of the power supply stabilization means.

  The control means controls the overall operation of the measurement system with the voltage stepped down from the power source and controls the power supply to the transducer that transmits the ultrasonic wave using the same stable voltage. This makes it possible to realize accurate flow measurement that realizes stable operation of the measurement system by suppressing the instability of voltage and switching noise caused by operations such as boosting, and the system without reducing power conversion efficiency Operation can be performed.

  In the second invention, in particular, an opening / closing means is provided between the power stabilization means and the transmission means of the first invention, and the control means operates the opening / closing means to supply power to the vibrator driving circuit. Can be adjusted.

  In particular, the third invention provides a second power supply stabilizing means between the power supply of the first invention and the transmitting means, and the power supply control means controls the second power supply stabilizing means, so that the control system other than the control system is provided. The power supply to the circuit for driving the vibrator can be adjusted by the power supply.

  In the fourth aspect of the invention, in particular, the second opening / closing means is provided before or after the second power supply stabilizing means of the third invention, and the control means operates the second opening / closing means to drive the vibrator. The power supply to the circuit can be adjusted independently.

  In the fifth invention, in particular, the power supply control means of the first invention operates the opening / closing means after the power supply output of the power supply stabilization means is stabilized, so that the circuit voltage of each part is changed after the operation of the control means is stabilized. Since the transmission operation is performed after the fixed and steady operation, the stability of both the transmission operation of the vibrator and the peripheral circuit can be improved.

In the sixth aspect of the invention, in particular, when the power supply control means of the first aspect of the invention operates the opening / closing means after the power supply output of the power supply stabilization means has stabilized for a certain time, the output voltage of the power supply stabilization means is stabilized, Since the transmission operation of the vibrator can be performed after the circuit voltage is determined and the initial operation is completed, the stability of both the ultrasonic drive operation and the peripheral circuit can be improved.

  In the seventh aspect of the invention, in particular, the power supply control unit of the first aspect of the invention starts the power supply to the transmission unit after the output of the control unit is stabilized by closing the opening / closing unit before the operation of the transmission unit starts. As a result, unnecessary voltage application to the vibrator can be prevented.

  In the eighth invention, in particular, the power control means of the first invention opens the opening / closing means after a lapse of a certain time after the operation of the transmission means, thereby eliminating voltage application to the vibrator after the transmission operation is completed. Unnecessary vibration operation can be prevented.

  According to the ninth aspect of the invention, in particular, the main control means is provided in the flow measuring device of the first aspect of the invention, and the power supply voltage management can be easily performed by the configuration in which the power supply stabilization means collectively performs the subsequent power management.

  According to a tenth aspect of the invention, in particular, a voltage detection means for detecting an input voltage of the power supply stabilization means of the first invention is provided, and the main control means performs subsequent power management from the power supply stabilization means by a signal of the voltage detection means. Thus, it is possible to adjust the control method according to the input voltage and to operate stably.

  In the eleventh aspect of the invention, in particular, there is provided a configuration having a program for causing a computer to function as the control means in any one of the first to tenth aspects of the invention. In addition, since it is possible to flexibly cope with aging, etc., the accuracy of the power supply voltage to the vibrator and the system reliability can be improved more flexibly.

(Embodiment 1)
A flow measurement apparatus according to the first embodiment of the present invention will be described.

  FIG. 1 shows a block diagram of a flow measuring apparatus according to the first embodiment of the present invention.

  In FIG. 1, a flow path 31 through which a fluid to be measured flows, a first vibrator 32 and a second vibrator 33 that transmit and receive ultrasonic waves arranged in the flow path 31 are installed, and the first vibration is provided. A transmission means 34 for driving the child 32; a reception means 35 for receiving a reception signal of the second vibrator 33; and determining a reception timing; the transmission means 34, the first vibrator 32, and a second vibrator; A switching unit 36 is provided between the first transducer 32 and the receiving unit 35 so that transmission / reception of ultrasonic waves is alternately performed between the first transducer 32 and the second transducer 33.

  The repeater 37 for measuring the number of operations of receiving and receiving the output of the receiver 35 and repeating the transmission / reception of the ultrasonic wave again via the transmitter 34 and stopping the operation at a predetermined number of times, and receiving a signal of the repeater 37 for a predetermined delay A delay unit 38 that outputs the trigger signal of the transmission unit 34 with a time delay, and at least the propagation time of the ultrasonic wave from the start of driving the first vibrator 32 by the transmission unit 34 to the stop of the operation of the repeating unit 37 are measured. It has time measuring means 39 and flow rate calculating means 40 (corresponding to the calculating means in the claims) for calculating the flow velocity between the pair of vibrators from the value of the time measuring means 39 and obtaining the flow rate therefrom.

  Further, a control unit 45 is provided, and the measurement control unit 41 of the control unit 45 outputs a measurement start signal for operating the transmission unit 34. Furthermore, a power supply 42 for supplying power, a power supply stabilization means 43 for operating the control means 45 operating at a lower voltage than the power supply, and a power supply control means 44 for controlling the power supply stabilization means 43 are provided.

  Normal operation will be described. Upon receiving the start signal from the measurement control means 41, the transmission means 34 pulse-drives the first vibrator 32 for a fixed time, and at the same time, the time measurement means 39 starts measuring time according to the signal from the measurement control means 41. An ultrasonic wave is transmitted from the pulse-driven first vibrator 32. The ultrasonic wave transmitted from the first vibrator 32 propagates through the fluid to be measured and is received by the second vibrator 33. The reception output of the second vibrator 33 amplifies the signal by the receiving means 35 and then determines the reception of the ultrasonic wave at the signal level at a predetermined reception timing. When the repeated operation is not performed, the operation of the time measuring means 39 is stopped when the reception of the ultrasonic wave is determined, and the flow velocity is obtained from the time information t by (Equation 1).

  Here, the measurement time obtained from the time measuring means 39 is t, the effective distance in the flow direction between the ultrasonic transducers is L, the sound velocity is c, and the flow velocity of the fluid to be measured is v.

v = (L / t) -c (Formula 1)
The receiving means 35 is usually configured to compare the reference voltage and the received signal by a comparator.

  In the current operation using the repeating unit 37, the determination result of the receiving unit 35 is delayed by a delay unit 38 for a certain period of time, then returned to the transmitting unit 34 and transmitted again. The repetitive operation is performed a predetermined number of times, the time is measured by the time measuring means 39, and the flow velocity is obtained by the calculation of (Equation 2) based on the measurement time of the time measuring means 39.

  Here, the delay time of the delay means is Td, the number of repetitions is n, the measurement time is ts, the effective distance in the flow direction between the ultrasonic transducers is L, the sound velocity is c, and the flow velocity of the fluid to be measured is v.

v = L / (ts / n−Td) −c (Expression 2)
According to this method, it is possible to measure with higher accuracy than the method of (Equation 1).

  Further, the first ultrasonic transducer 32 and the second ultrasonic transducer 33 are switched, and the respective propagation times of the fluid under measurement from upstream to downstream and from downstream to upstream are measured. Find v.

  Here, the measurement time from upstream to downstream is t1, and the measurement time from downstream to upstream is t2.

v = L / 2 ((1 / t1)-(1 / t2)) (Formula 3)
According to this method, the flow rate can be measured without being affected by the change in the sound speed, and thus it is widely used for measuring the flow velocity, the flow rate, the distance, and the like. When the flow velocity v is obtained, the flow rate can be derived by multiplying it by the cross-sectional area of the flow path 1.

  Normal operation is as shown in the timing diagram of FIG. That is, measurement is started from the start signal at time t0 by the measurement control means 41, and the first ultrasonic transducer 32 is driven via the transmission means 34 at t1. The ultrasonic signal generated there propagates in the flow path, reaches the second ultrasonic transducer 33 at time t2, and when the reception means detects the reception point, the repeat means 37 does not reach the set number of times. A signal is sent to the means 38. Then, the delay means 38 starts operating from time t3, operates for a predetermined time, and then sends a signal to the transmitting means 34 at time t4 to drive the first ultrasonic transducer 32 again. This is repeated below.

  When the number of times determined by the repeating means 37 is operated, the transmission / reception operation stops at time t5 in FIG. 2, and the time is T shown in the figure. Thereafter, the switching means 36 switches between transmission and reception. That is, the first ultrasonic transducer 32 is the reception side, and the second ultrasonic transducer 33 is the transmission side. Then, the same repeated operation is performed.

  Next, the vicinity of the power source that supplies power to the measurement control means 41 and the like will be described. FIG. 3 is a block diagram showing a configuration around the power source according to the present embodiment. In FIG. 3, reference numeral 42 denotes a power source, 43 denotes a power source stabilization means, and 44 denotes a power source control means. As an example of the power supply stabilizing means 43, a three-terminal regulator or a Zener diode can be used.

  It is also possible to use a step-down DCDC converter that has been improved in recent years.

  A difference from the conventional example will be described with reference to the timing of FIG. FIG. 4A shows the operation timing of the vibrator 32 which is a load in the DCDC converter 2 which is a conventional booster circuit. As the vibrator operates, the output voltage of the boosting means 2 decreases as shown in FIG. Then, it is detected that the voltage has dropped at t1, and the DCDC converter operates.

  The timing of t1 is determined only by the voltage and does not consider the operation of the vibrator. Therefore, as shown in FIG. 4, even when the voltage is lowered during operation of the vibrator 32, the DCDC converter immediately starts the boosting operation. This indicates that the terminal voltage of the vibrator 32 fluctuates during operation. If it is used in a measuring device, the operating voltage fluctuates and the stability becomes worse. Similarly, FIG. 4C shows the operation timing of the vibrator of the present invention. FIG. 4D shows the operation timing of the power supply control means 44. For example, it may operate to supply power to the transmission means 34 every time it transmits, or the voltage of the transmission means 34 may be confirmed to confirm the operation. As shown in FIG. 4E, the voltage from the output of the power supply stabilization means 43 can be used as it is as the input voltage of the transmission means 34, so that a constant voltage can be maintained regardless of the operation of the vibrator. .

  The case where the power supply control means 44 is incorporated in the flow measuring device as shown in FIG. 5 will be described. The ultrasonic signal is received by the second vibrator 33 after driving the first vibrator 32 and transmitting the inside of the flow path 31 at a sufficient ultrasonic signal level. If the output of the power source stabilization means 43 is used as it is for the driving voltage of the vibrator, it is not a high voltage as usual, so that an ultrasonic level to be transmitted can be secured by using a vibrator with good signal conversion efficiency, or a weak signal However, it is necessary to use a highly sensitive transducer that can be received. Of course, when the reception level is low, it is also necessary to configure a receiving means that can obtain a high amplification degree with low noise.

  The output passing from the power source 42 through the power source stabilization means 43 is connected to the first vibrator 32 via the transmission means 34. Since the switching means 36 on the way only switches between transmission and reception, a detailed description here is omitted. As an example of the inside of the transmission unit 34, a bridge configuration using transmission opening / closing units 34a to 34d is used to operate the vibrator. First, the transmission opening / closing means 34a and 34d are energized, and on the contrary, 34b and 34c are opened. Next, the transmission opening / closing means 34a and 34d are opened, and 34b and 34c are energized. With this operation, the vibrator starts to operate. In this way, the power supply to the vibrator is directly performed at the same voltage as the measurement system from the power supply stabilizing means 43.

  If the supply of this voltage varies as shown in FIG. 4B, the received signal will not be constant. This is not preferable because it greatly affects the measurement accuracy of the flow rate. The operation of the power supply stabilizing means 43 can stabilize the transmission signal by supplying power to the vibrator with a stable voltage as shown in FIGS. Furthermore, since there is no need to produce a high-voltage power supply, it is possible to realize an operation that does not affect the entire flow rate measurement system due to noise or the like.

  Since the power supply control unit 44 can receive the measurement operation signal from the measurement control unit 41 as a signal, the power control unit 44 mainly manages the voltage of the entire system in a state that does not affect the operation of the vibrator more reliably. You will be able to control. In FIG. 5, the power supply control means 44 and the measurement control means 41 are provided separately, but one logic means, for example, a microcomputer may be used as the same control means.

  By supplying a stable voltage from the power source 42 to the measurement system and the vibrator via the power source stabilizing means 43, it is possible to reduce the number of components around the power source and to realize power saving. In addition, since the voltage of the power supply is one, the possibility of trouble due to current wraparound due to a voltage difference can be reduced. Furthermore, space can be saved by omitting a circuit for producing a high voltage. Also, noise generation can be suppressed by omitting a circuit including a coil such as a DCDC converter.

  The timing around the power supply at the start of operation will be described. Many control means use a method in which the power supply is frequently turned on when operating with power saving, the power supply is supplied to each unit only when the operation is really necessary, and the rest is performed otherwise. In a device that operates periodically, such as a flow rate measuring device, it is useful to shut off the power supply when not operating. As a result, the power-on operation frequently occurs, but it is necessary to make various settings each time. If power supply is started from the power supply stabilization means 43 before the supply voltage to the transmission means 34 and the reception means 35 is stabilized, there is a possibility that waste will occur in the time until the vibrator as a load operates and the degree of voltage stability in each part There is a possibility that an unstable operation may occur due to the unbalance. Further, if the transmission unit 34 operates during the initial setting operation of the measurement control unit 41, the system voltage may fluctuate, or the measurement accuracy may deteriorate due to the generation of noise. For example, there is a case where a plurality of integrated circuits exist inside the measurement control means 41, and exchange of initial data and adjustment of an analog unit are performed.

  In such a case, an opening / closing means 46 may be installed as shown in FIG. 6 so that the power supply control means 44 issues an opening / closing instruction. The opening / closing means 46 is opened in order to prevent an inadvertent voltage from being applied to the vibrator 32 until each means inside the control means 43 is stabilized. The operation will be described with reference to FIG.

  As shown in FIG. 7A, when the voltage of the input unit of the power supply control unit 44 rises and exceeds the specified voltage, the digital device starts operation as shown in FIG. 7B. At time t1, the measurement control means 41 starts its operation and starts performing initial setting. Then, after the setting of each part is completed in the time until t2, the power supply control means 44 sends a signal for closing the opening / closing means 46 as shown in FIG. When the opening / closing means 45 is closed, the input voltage of the transmission means 34 satisfies a predetermined voltage at the rising edge t3 as shown in FIG. Thereafter, the measurement control unit 41 operates the transmission unit 34. By sharing the stable circuit voltage and the transmission voltage in this way, it is possible to realize an accurate flow rate measurement that realizes a stable operation of the measurement system. Further, by operating the opening / closing means 45 after setting an analog circuit or the like, it is possible to realize an operation that does not affect the system by noise or the like.

  Since the transmission voltage is lower than that of the conventional measurement system, the reception level may be reduced, but by eliminating the part that may generate noise such as boosting means by unifying the power supply, the voltage level is stable. The operation of the receiving means is also possible, and the gain can be increased.

  Further, another operation will be described with reference to FIG. Although the control unit 44 operates at a stable voltage from the power source 42 through the power source stabilization unit 43, the power supply to the transmission unit 34 may be performed directly from the power source 42 in some cases. A second power stabilizing unit 47 is provided between the power source 42 and the transmitting unit 34 so that power is supplied to the vibrator from the second power stabilizing unit 47. Depending on the sensitivity of the vibrator, there may be cases where the voltage is lower or higher than the voltage of the power stabilization means 43, and even if the vibrator can operate at the same voltage as the power stabilization means 43, it is transmitted. Since there is a possibility that the voltage of the measurement system will fluctuate due to a transient current flowing at the timing, another power supply system is prepared. By having the second power supply stabilizing means 47 in this way, the control means 43 can independently adjust the power supply to the vibrator driving circuit from the measurement system. The output voltage of the first power stabilization means 47 does not have to be the same as the output voltage of the power stabilization means 43.

  Further, another operation will be described with reference to FIG. When the second power supply stabilizing means 47 is provided, the timing around the power supply at the start of operation will be described. Many control means use a method in which the power supply is frequently turned on when operating with power saving, the power supply is supplied to each unit only when the operation is really necessary, and the rest is performed otherwise. In a device that operates periodically, such as a flow rate measuring device, it is useful to shut off the power supply when not operating. As a result, the power-on operation frequently occurs, but it is necessary to make various settings each time. At the time when the control unit 41 starts to operate due to the power supply from the power supply stabilization unit 43, there are cases where initial setting of other measurement systems is performed, and transmission is not performed immediately. In addition, since the second power stabilizing means supplies power only to the transmitting means 34, considering the power capacity and the like, the second power stabilizing means may be small and start up quickly. Therefore, as shown in FIG. 8, the second opening / closing means 48a may be installed in the front stage of the second power supply stabilizing means 47, or 48b in the rear stage, so that the power supply control means 44 issues an opening / closing instruction. .

  Then, the second opening / closing means 48 is opened in order to prevent an inadvertent voltage from being applied to the vibrator 32 until each means inside the control means 43 is stabilized. When the control means 43 is stabilized, the second opening / closing means 48 is closed by a signal from the power supply control means 44, and power supply from the power supply 42 to the transmission means 34 is started via the second power supply stabilization means 47. By performing the initial rising operation of the stable circuit voltage and the transmission voltage in this way, it is possible to realize a highly accurate flow rate measurement that realizes a stable operation of the measurement system. Furthermore, by operating the second opening / closing means 48 after setting an analog circuit or the like, it is possible to realize an operation that does not affect the system, such as noise, and to improve the stability of both the transmission operation of the vibrator and the peripheral circuit. Is possible.

  Further, another operation will be described with reference to FIG. When the power supply is frequently started up, if the transmission unit 34 is operated first while the voltage rise from the power supply 42 is not stable, the peripheral operation may be adversely affected. Therefore, when the voltage of the input part of the power supply control means rises as shown in FIG. 9A and exceeds the specified voltage at t0, the digital device starts operation as shown in FIG. 9B. Then, as shown in FIG. 9 (c1), the power supply control means 44 sends a signal to operate the opening / closing means 46 at t1. Since the power supply output is almost stable between time t0 and t1, the operation of each part is settled. In this way, the power supply control means 44 closes the opening / closing means 46 after the power supply output is stabilized, so that the output voltage of the power supply stabilization means 43 is stabilized, the circuit voltage of each part is determined, and the transmission means 34 is brought into a steady operation. Therefore, it is possible to improve the stability of both the operation of the vibrator as a load and the peripheral circuit. The same effect can be obtained by operating the opening / closing means 46 directly instead of operating the opening / closing means 46.

  As described above, the power supply control means 44 operates the opening / closing means 46 after the power supply output of the power supply stabilization means 43 is stabilized, so that the circuit voltage of each part is determined after the operation of the control means 41 is stabilized and the steady operation is performed. Since the transmission operation is performed later, the stability of both the transmission operation of the vibrator and the peripheral circuit can be improved.

  Further, another operation will be described with reference to FIG. Even if the power supply rises stably, the operation of other peripheral parts may not be stable yet. Therefore, as in the above operation, when the voltage at the input portion of the power supply control means 44 rises as shown in FIG. 9A and exceeds the specified voltage at t0, the digital device starts operation as shown in FIG. 9B. Then, after a predetermined time T has elapsed from t0, the power supply control means 44 sends a signal to operate the opening / closing means 46 at t2 as shown in FIG. 9 (c2). Since the operation and initial setting of the peripheral circuits are almost stable between the times t0 and t2, the operation of each part is also normal. Thus, instead of starting the operation immediately after the output voltage of the power source stabilization means 43 is stabilized, the circuit voltage of each part is determined after waiting for a certain period of time and the initial operation is completed, and the opening / closing means 46 is operated to apply the voltage to the transmission means. By applying the power, the power supply can be fed with a time delay without causing the output voltage of the power source stabilizing means 43 to flow. For this reason, since the transducer voltage can be transmitted after the circuit voltage of each part is determined and the initial operation is completed, it is possible to improve the stability of both the ultrasonic drive operation and the peripheral circuit.

(Embodiment 2)
A flow measuring apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 1, 5, 10, and 11. The difference from the first embodiment is that power is applied to the transmission means in the vicinity of the operation of the vibrator.

  First, the operation will be described with reference to FIG. 1, FIG. 5, and FIG. As shown in the first embodiment, it is desirable to supply power to a load such as a vibrator used in the flow rate measuring apparatus after the measurement system is stabilized. For this purpose, the opening / closing means 46 must perform a suitable operation. Therefore, the operation of the vibrator is stabilized by adjusting the timing of operating the opening / closing means 46. In order to operate the first vibrator 32 as shown in FIG. 10A at time t31, t33, t35, and t37 in FIG. 10, power supply from the power supply stabilizing means 43 is necessary. For this reason, before the vibrator operates, the power control means 44 operates the opening / closing means 46 at time t30, t32, t34, t36 as shown in FIG. Start. Although not shown before time t30, the opening / closing means 45 is operating because the vibrator is operating, but the description thereof is omitted because it is a repetitive operation.

  Since the operation of the vibrator serving as a load can be detected by the power control means 44 via the measurement control means 41, a signal is sent to the opening / closing means 46 to start power feeding from the power supply stabilization means 43 before the vibrator operates. Is possible. As a result, the input of the transmission means 34 shows a stable voltage state as shown in FIG. This is because the operation of the opening / closing means 45 is performed before the vibrator operates, so that the voltage becomes an optimum value, and it is possible to keep power supplyable when the vibrator serving as a load operates. Become.

  In FIG. 10 (b), the operation of the opening / closing means 45 is stopped immediately after the operation of the vibrator. However, the operation ends at a certain time ΔT2 before the operation of the vibrator as shown in FIG. 10 (b2). The power control means 44 may be adjusted as described above. This may be the case where a weak voltage change (noise) occurs in the entire system due to a change in the stop signal from the power control means 44. If a signal is sent before the vibrator operates for a certain time so that the voltage change does not affect other means, for example, after the reflection or damping signal by the signal converges, ultrasonic transmission / reception is performed after the entire system is stabilized The operation can be performed stably. In this case, it is necessary to place a capacitive element in the vicinity of the transmission means 34 to maintain the voltage.

  Further, power saving can be realized by frequently turning on and off the opening / closing means. Thus, when the operation of the transmission means 34 is completed, the power supply control means 44 opens the operation of the opening / closing means 46 so that power supply can be started before the load is operated. The system can be supplied and the stability of the system can be improved, and the time for supplying power to the transmission means can be shortened to enable the power saving operation.

  As described above, the power supply control means 44 closes the opening / closing means 46 before the operation of the transmission means 34 is started, whereby the power supply to the transmission means is started after the output of the control means 41 becomes stable. It becomes possible to prevent unnecessary voltage application to the child.

  Other operations will be described with reference to FIGS. 1, 5 and 11. FIG. By adjusting the timing of operating the opening / closing means 46, the operation of the vibrator is stabilized. When the first vibrator 32 operates as shown in FIG. 11A and the voltage may drop to some extent at times t40, t42, t44, and t46 in FIG. 11, as shown in FIG. 11B. The opening / closing means 46 is operated by the power supply control means 44 to supply power to the transmission means 34. Since the operation of the vibrator serving as a load can be detected by the power control means 44 via the measurement control means 41, the voltage can be adjusted by operating the opening / closing means 46 after the vibrator is operated. It becomes possible to adjust the gain of the receiving means by this voltage adjustment or voltage detection.

  By operating the opening / closing means 46, the output of the transmitting means 34 shows a stable voltage state as shown in FIG. This is because the voltage drop can be accurately grasped even after the vibrator is operated, supplemented by the opening / closing means 45, and the vibrator as the load can be operated next time after the boosted voltage is stabilized. When applied to flow measurement, etc., stable system operation can be performed. In this case, if a capacity is provided in front of the transmission means, it is further stabilized. For example, when a large capacitive load is connected to the switching means 46, the voltage rise also changes with a large time constant. However, if the voltage is adjusted after the operation of the vibrator is finished, the next vibration The voltage can be adjusted to a stable voltage with a margin long before the child operates.

  In FIG. 11 (b), the operation of the opening / closing means 45 is stopped immediately after the operation of the vibrator. However, as shown in FIG. 11 (b2), the operation is started at ΔT3 after a certain time after the vibrator is operated. The power control means 44 may adjust so as to. This is because the signal changes due to high-frequency operation or the like immediately after the vibrator is operated, so that a voltage change including the ground may occur in the entire system. When the voltage change affects other means, for example, the power supply control means 44 may not be able to detect the accurate output voltage of the opening / closing means 46.

  Therefore, stable power management can be performed by performing a power feeding operation after the electric signal of the entire system is stabilized after the vibrator is operated. Further, power saving can be realized by frequently turning on / off the opening / closing means 46. As described above, the power supply control means 44 starts the operation of the opening / closing means 46 after the operation of the transmission means 34 is completed and prepares for the next operation of the vibrator, so that the operation is stable with sufficient time before the operation of the vibrator. The power supply operation is enabled and the stability of the system is improved, and the operation time of the opening / closing means is shortened to enable the power saving operation. In this way, the power supply control means 44 stops the operation of the opening / closing means 46 after a lapse of a certain time after the operation of the transmission means 34, so that the transmission operation can be performed at a stable voltage, and then a sufficient boosting operation is performed. It is possible to prepare for the next operation by stopping the operation.

  Further, the power supply control means 44 opens the opening / closing means 46 after a lapse of a certain time after the operation of the transmission means 34, thereby eliminating the voltage application to the vibrator after the transmission operation is completed and preventing unnecessary vibration operation. It becomes possible.

  In FIG. 11, the opening / closing means 46 always operates after the vibrator is operated. However, by installing a capacitive element in front of the transmitting means 34 and charging it, the switching means 46 is operated every predetermined number of times. The opening / closing means 46 may be operated after the vibrator is operated every number of times corresponding to the common divisor.

(Embodiment 3)
A flow measuring apparatus according to a third embodiment of the present invention will be described with reference to FIGS. The difference from the first embodiment is that the main control means 49 is provided and the power supply stabilization means 43 performs subsequent power management.

  The operation will be described. The main control means 49 operating with the power supply 42 can always operate regardless of the power supply stabilization means 43. Also, by incorporating a timer in itself, it is possible to reduce power by pausing for a certain period of time in the sleep operation. The main control means 49 operates the power supply stabilization means 43 at regular intervals and controls the control means 41 and the subsequent stages to operate. For example, the main control means 49 sends a signal to the power stabilization means 43 to start power supply. The control means 41 starts to operate only after power is supplied. Until then, the power supply stabilization means 43 is also stopped to save power. In this way, by performing the operation of the power supply stabilization means 43 from the outside, it is possible to further reduce the power by the configuration in which the power management of the entire system is collectively managed.

  By performing the measurement cycle and power management by the main control means 49, the control means 41 can concentrate on the measurement, so that a complicated operation taking into account the precision by fine case classification etc. is sufficient within the determined time. It becomes possible to do.

  Further, another operation will be described with reference to FIG. Although the control means 41 operates at a stable voltage from the power supply 42 via the voltage stabilization means 43, there is a possibility that the operation becomes unstable when the voltage of the power supply 42 decreases. Therefore, the voltage of the power supply 42 is detected by the voltage detection means 50, and the main control means 49 adjusts the power supply stabilization means 43 according to the input voltage. For example, when the voltage is lowered, it is possible to make a judgment such as extending the operation cycle to avoid malfunction due to the voltage drop.

  Further, when the power source drops to a predetermined voltage, the main control means 49 enters another control operation stored therein, lowers the operation cycle of the main control means itself, or sends a signal to the control means 41 to repeat the operation. It is possible to take measures to perform long-term operation such as adjusting.

  As described above, the main control means 49 can operate stably by adjusting the control method according to the input voltage by performing the subsequent power management from the power stabilizing means 43 by the signal of the voltage detecting means 50. Become.

(Embodiment 4)
A flow measuring apparatus according to a fourth embodiment of the present invention according to claim 11 will be described. The difference from the first embodiment is that a storage medium 51 having a program for causing a computer to function to ensure the operation of the power supply control means 44 for adjusting the operation of the power supply 42, the transmission means 34, and the opening / closing means 46 is used. It is that.

  In FIG. 1, FIG. 5, FIG. 6, FIG. 8 and FIG. 12, in order to perform the operation of the power supply control means 44 shown in the first to third embodiments, the transmission means 43 based on the operation of the vibrator is previously tested. Correlation of the operation timing of the transmission means with respect to environmental change factors such as output change, aging change, temperature change, system stability, etc., for example, judgment is made in the form of fitness like a membership function of fuzzy control Determination software is stored in the storage medium 51 as a program. Usually, it is convenient to use an electrically writable memory such as a microcomputer memory or a flash memory.

  As described above, when the operation of the power supply control unit 44 can be performed by a program, the operation of the transmission unit 43 that follows the change in the driving voltage of the vibrator is performed by software. This makes it easy to set the conditions for the number of transmissions, set the conditions for voltage adjustment before and after the switching means 36 operation, set the operation around the power supply, and change it flexibly. It is possible to improve power supply accuracy, system reliability, and measurement time. In the present embodiment, operations other than the power supply control means 44 may be performed by a program using a microcomputer or the like.

  The flow measurement device of the present invention also has trouble and noise problems caused by potential difference in the measurement system by supplying the same voltage from the power supply that supplies power to the normal measurement means. It is possible to measure the flow velocity and flow rate of gases and liquids in a stable state, and it can be applied to applications such as gas meters and measuring devices for various fluids.

FIG. 1 is an overall block diagram of a flow measuring apparatus according to Embodiment 1 of the present invention. Timing diagram showing the operation of the flow measurement device 1 is a block diagram around a power source in a first embodiment of the present invention Timing diagram showing the operation of the flow measuring device of the present invention Block diagram showing connections around the transmission means of the same flow measurement device Block diagram showing the connection around the opening and closing means of the flow measurement device Timing diagram showing the operation of the flow measurement device Block diagram showing the connection around the second power stabilization means of the flow measuring device Timing diagram showing the operation of the power supply in the same flow measurement device Timing chart showing the operation of the flow measuring apparatus according to the second embodiment of the present invention. Timing diagram showing the operation of the flow measurement device The block diagram which shows the connection of the voltage detection means periphery of the flow measurement apparatus of Embodiment 3 of this invention Overall block diagram of conventional booster circuit Overall block diagram of a conventional flow measurement device

Explanation of symbols

31 Flow path 32 First vibrator 33 Second vibrator 34 Transmitting means 35 Receiving means 36 Switching means 37 Repeating means 38 Delay means 39 Timing means 40 Flow rate calculating means (calculating means)
42 Power supply 43 Power supply stabilization means 44 Power supply control means 45 Control means 46 Opening / closing means 47 Second power supply stabilization means 48 Second opening / closing means 49 Main control means 50 Voltage detection means 51 Storage medium

Claims (11)

A pair of transducers arranged in the flow path of the fluid to be measured and transmitting / receiving ultrasonic waves, a transmission unit that drives the transducers, a reception unit that converts an output signal of the reception-side transducer into an electrical signal, and the vibrations A transmission / reception switching means, a repetition means for performing ultrasonic propagation between the vibrators a plurality of times, a delay means for delaying a transmission signal from a transmission-side vibrator during the repetition, and a transmission / reception of the vibrator A time measuring means for measuring the propagation time of ultrasonic propagation repeated several times, a calculating means for calculating a flow velocity or a flow rate based on a difference between the respective time measured values by the time measuring means, a power source, and a voltage lower than the power source. A flow measuring apparatus comprising: a power supply stabilizing means and a control means, wherein the control means includes a power supply control means for controlling the transmitting means with an output of the power supply stabilizing means. The flow measuring apparatus according to claim 1, wherein an opening / closing means is provided between the power stabilization means and the transmission means, and the control means operates the opening / closing means. 2. The flow measuring device according to claim 1, wherein a second power stabilizing unit is provided between the power source and the transmitting unit, and the power control unit controls the second power stabilizing unit. 4. The flow measuring apparatus according to claim 3, wherein a second opening / closing means is provided before or after the second power supply stabilizing means, and the control means operates the second opening / closing means. 2. The flow measuring device according to claim 1, wherein the power control means operates the opening / closing means after the power output of the power stabilization means is stabilized. 2. The flow measuring device according to claim 1, wherein the power control means operates the opening / closing means after a predetermined time has elapsed after the power output of the power stabilization means has stabilized. 2. The flow measuring device according to claim 1, wherein the power control means closes the opening / closing means before the operation of the transmission means is started. 2. The flow measuring device according to claim 1, wherein the power control means opens the opening / closing means after a predetermined time has elapsed after the operation of the transmission means is completed. The flow measuring device according to claim 1, wherein main flow control means is provided, and power management in the subsequent stage is performed from power supply stabilization means. 2. The flow measuring apparatus according to claim 1, further comprising a voltage detection unit configured to detect an input voltage of the power supply stabilization unit, wherein the main control unit performs subsequent power management from the power supply stabilization unit based on a signal from the voltage detection unit. 11. The flow measurement apparatus according to claim 1, wherein a program for obtaining a correlation between an environmental change factor of the transmission unit and an operation timing of the transmission unit in a computer provided in the control unit.

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