JP3443659B2 - Flow measurement device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate measuring device for measuring the flow rate of gas or the like by utilizing ultrasonic waves.

[0002]

2. Description of the Related Art A conventional flow rate measuring device of this kind uses a battery as a power source and generally has a structure as shown in FIG. This device is a switching means for switching between transmission and reception of the first ultrasonic oscillator 32 and the second ultrasonic oscillator 33, and the first ultrasonic oscillator 32 and the second ultrasonic oscillator 33 installed in the flow path 31 through which the fluid flows. 34, a transmitting unit 35 that drives the first ultrasonic transducer 32 and the second ultrasonic transducer 33, and a signal that is received by the ultrasonic transducer on the receiving side and that has passed through the switching unit 34 is amplified to a predetermined amplitude. The amplifying means 36, the reference comparing means 37 for comparing the voltage of the received signal amplified by the amplifying means 36 with the reference voltage, and the reference comparing means 37 for comparing with the reference voltage as shown in FIG. The determining means 38 that outputs the output signal D to the repeating means 39 at the first zero-cross point a of the later amplified signal, and the signal from this determining means 38 is counted and counted a preset number of times, and the determining means 38 is also counted. These signals are output to the control means 42, the repeating means 39, the time measuring means 40 for measuring the time counting the number of times preset by the repeating means 39, and the flow rate is calculated according to the time measured by the time measuring means 40. The flow rate calculating means 41, the flow rate output calculated by the flow rate calculating means 41, and the signal from the repeating means 39 are transmitted by the transmitting means 35.
It comprises a control means 42 for controlling the above operation, a judgment means 38, a repeating means 39, a time counting means 40, a flow rate calculating means 41, and a control means 42.

In this device, the control means 42 controls the transmission means 3
5, the ultrasonic signal transmitted from the ultrasonic transducer 32 propagates in the flow, is received by the second ultrasonic transducer 33, is amplified by the amplification means 36, and is then amplified by the reference comparison means 37 and the determination means 38. Then, the signal is processed by and is input to the control means 42 through the repeating means 39. This operation is repeated n times set in advance, and the time interval is measured by the time measuring means 40. Then, the first ultrasonic transducer 32 and the second ultrasonic transducer 33 are switched by the switching means 34 to perform the same operation, and the fluid to be measured is changed from upstream to downstream (this direction is a forward flow) and downstream. From the upstream to the upstream (this direction is the reverse flow), and the flow rate Q was obtained from (Equation 1) (the effective distance in the flow direction between the ultrasonic transducers is L, and the upstream to the downstream). The measurement time for n times is t1, the measurement time for n times from downstream to upstream is t2, the flow velocity of the fluid to be measured is v, the cross-sectional area of the flow path is S, the sensor angle is φ, and the flow rate is Q).

Q = S.v = S.L / 2.cosφ ((n
/ T1)-(n / t2)) (Equation 1) (Actually, Equation 1 is multiplied by a coefficient corresponding to the flow rate to calculate the flow rate). Further, the gain of the amplification means 36 is the ultrasonic vibration on the receiving side. The gain is adjusted so that the signal received by the child has a constant amplitude, and after the flow rate measurement, the repeating unit 39
The ultrasonic wave signal is transmitted and received again by setting the number of times smaller than that at the time of measurement, and the peak voltage value of the received signal at that time is adjusted to fall within a predetermined voltage range. This is the same as the number of times that the peak voltage value of the reception signal is below the lower limit of the predetermined voltage range as shown by the reception signal b shown by the dotted line in FIG. 18 during the repetition of the measurement of the number of times set in the repeating means 39. As indicated by a reception signal c indicated by a dotted line in FIG. 18, the number of times the voltage exceeds the upper limit of the predetermined voltage range is counted, and the gain at the next flow rate measurement is adjusted based on the magnitude relationship. (For example, if the number of times of falling below the lower limit is large, the gain is increased so that it falls within the upper limit and the lower limit of the voltage range as shown by the reception signal a shown by the solid line in FIG. 18.) The reason for transmitting and receiving the sound wave signal with a smaller number of times than when measuring the flow rate is when the number of times that deviates from the above voltage range is not counted as much as the set number of times when measuring the flow rate. There is also one in which the number of digits is increased so as to be able to count the set number of times when the flow rate is measured, and the ultrasonic signal for gain adjustment is not transmitted and received after the flow rate is measured.

[0005]

However, since the above-mentioned conventional flow rate measuring device is required to have an operating life of 10 years or more when it is driven by a battery, it is a problem to reduce the current consumption, and particularly the amplifying means which consumes a large current. And the reduction of current consumption of the reference comparison means was a problem. Normally, the amplifying means and the reference comparing means anticipate the arrival time of the reception signal of the ultrasonic transducer on the receiving side, and in consideration of the stabilization waiting time of the circuit operation, supply the power shortly before the arrival time of the reception signal (about 50 μs). However, in order to adjust the gain of the amplifying means, the power supply is cut off after a short delay (about 10 to 20 μs) from the arrival of the received signal so as to include the maximum value of the received wave. The amplification means and the reference comparison means consume a current of about several hundred μA and occupy most of the operating current of the measuring device due to the functional characteristics of amplification and generation of the reference voltage.

An object of the present invention is to solve the above conventional problems and to provide a flow rate measuring device in which the operating currents of the amplifying means and the reference comparing means are reduced.

[0007]

In order to solve the above-mentioned problems of the prior art, the flow rate measuring device of the present invention uses the power supply means to compare the amplification means and the reference in accordance with two states of gain adjustment and non-gain adjustment. By changing the power-off timing of the means, the total operating time of the amplifying means and the reference comparing means during the measurement period can be shortened and the current consumption thereof can be suppressed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 is a first vibrator and a second vibrator which are provided in a fluid line and which transmit and receive ultrasonic signals.
An oscillator, a transmitting unit that drives the oscillator, a switching unit that switches between transmission and reception of the oscillator, an amplification unit that amplifies a received signal of the oscillator, and an exchange of ultrasonic signals between the oscillators. Repeating means for performing a plurality of times, flow rate calculating means for calculating a flow rate based on the cumulative time of transmission and reception of the ultrasonic signal, reference comparing means for comparing the output voltage of the amplifying means with a reference voltage, and the reference comparing Means and the output of the amplifying means for determining the arrival time of the ultrasonic signal, and control of power supply to the amplifying means and the reference comparing means after the determination means determines the arrival time of the ultrasonic signal By using the flow rate measuring device provided with the power supply means for performing the above, when the gain of the amplification means is not adjusted, the power supply means accelerates the power cutoff time to the amplification means and the reference comparison means. It may be a flow rate measuring device operating current is suppressed by shortening the operation time of the reference comparator.

The invention according to claim 2 is the flow rate measuring device according to claim 1, wherein the power supply means changes the supply timing by a predetermined number of repetitions or more of a plurality of repetitions of transmission and reception of ultrasonic signals by the repetition means. As a result, when the number of repetitions of the repeating means exceeds a predetermined number, the power supply means advances the cutoff time of the power supply to the amplifying means and the reference comparing means to shorten the operating time of the amplifying means and the reference comparing means, thereby suppressing the operating current. It can be a flow measuring device.

According to a third aspect of the present invention, there is provided timing determination means for detecting the output timing of the maximum value of the output signal of the amplification means, and the power supply means changes the power supply timing according to the output of the timing determination means. With the above flow rate measuring device, the timing determination means detects the output timing of the maximum value of the output signal of the amplification means, and the power supply means cuts off the power supply to the amplification means and the reference comparison means by this detection output. As a result, the operating periods of the amplifying means and the reference comparing means can be set without waste, and a flow rate measuring device in which the operating current is suppressed can be provided.

According to a fourth aspect of the invention, the timing determining means detects the output timing of the maximum value of the output signal of the amplifying means by the output pulse width of the reference comparing means, thereby determining the timing. The means detects the output timing of the maximum value of the output signal of the amplifying means based on the output pulse width of the reference comparing means, and the power supply means cuts off the power supply to the amplifying means and the reference comparing means by the detected output. As a result, the operating periods of the amplifying means and the reference comparing means can be set without waste, and a flow rate measuring device in which the operating current is suppressed can be provided.

According to a fifth aspect of the invention, the timing determining means detects the output timing of the maximum value of the output signal of the amplifying means based on the presence / absence of the output of the reference comparing means. The judging means detects the output timing of the maximum value of the output signal of the amplifying means based on the presence or absence of the output of the reference comparing means, and the power supply means shuts off the power supply to the amplifying means and the reference comparing means by this detection output. As a result, the operating periods of the amplifying means and the reference comparing means can be set without waste, and a flow rate measuring device in which the operating current is suppressed can be provided.

According to a sixth aspect of the present invention, the timing determining means is an output signal from the amplifying means after the output of the determining means.
4. The flow rate measuring device according to claim 3, wherein the signal is output to the power supply means by the wave number of, the power supply is provided when the output signal of the amplifying means after the output of the reference comparing means is reached by the timing determining means. Output to the supply means, and the power supply means cuts off the power supply to the amplification means and the reference comparison means. As a result, the operating periods of the amplifying means and the reference comparing means can be set without waste, and a flow rate measuring device in which the operating current is suppressed can be provided.

A seventh aspect of the present invention is a program for causing a computer to function as all or a part of the means of the flow rate measuring device according to any one of the first to sixth aspects. Since it is a program, part or all of the flowmeter-side device of the present invention can be easily realized by using a microcomputer or the like, and changes in characteristics such as ultrasonic transducer changes or aging changes and operations are realized. It is possible to flexibly respond to changes in setting conditions and constants. Moreover, the program can be easily distributed by recording it on a recording medium or distributing the program using a communication line.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram of a flow rate measuring device in a first embodiment according to claims 1 and 7 of the present invention. FIG. 2 is an operation explanatory diagram of the flow rate measuring device of the first embodiment, and FIG. 3 is a flowchart of the same.

In FIG. 1, a first ultrasonic transducer 2 for transmitting ultrasonic waves and a second ultrasonic transducer 3 for receiving ultrasonic waves are arranged in the flow path 1 at an angle φ in the flow direction. Reference numeral 5 is a transmitting means to the first ultrasonic transducer 2, 4 is a switching means for switching the transmission and reception of the first ultrasonic transducer 2 and the second ultrasonic transducer 3, and 6 is an ultrasonic transducer on the receiving side. Amplifying means for amplifying the received signal with a gain instructed by the control means 12, 7
Is a reference comparing means for comparing the signal amplified by the amplifying means 6 with a reference voltage, and 13 is a power supply means for controlling the power supply to the amplifying means 6 and the reference comparing means 7 by the signal from the control means 12. Then, when a signal from the control means 12 is sent to the amplifying means 6 and the reference comparison means 7 to advance the power-off timing, the power supply is shut off by the signal from the determination means 8, and the signal from the control means 12 is supplied to the power source. If it is a signal indicating that the shut-off time is not advanced, the power is shut off after a predetermined time from the signal of the determination means 8. Reference numeral 8 is a judging means for judging the arrival time of the ultrasonic wave from the output of the reference comparing means 7 and the signal amplified by the amplifying means 6, and 9 is a control means 12 for counting the signals of the judging means 8 for a preset number of times. It is a repeating means for outputting a repeating signal to. Reference numeral 10 is a time measuring means for measuring the time counted a number of times set in advance by the repeating means 9, and 11 is a flow rate calculated in consideration of the size of the pipeline and the flow state according to the time measured by the time measuring means 10. It is a flow rate calculating means for performing. Reference numeral 12 is a control means for controlling the operations of the transmission means 5, the amplification means 6, and the power supply means 13 for receiving signals from the flow rate calculation means 11 and the repetition means 9.

The operation and action of the flow rate measuring device constructed as above will be described below. First, the control means 1
When the flow rate measurement 2 starts the flow rate measurement, the transmission means 5 is operated to transmit an ultrasonic signal from the first ultrasonic transducer 2 (step 1 in FIG. 3).

When a predetermined time has elapsed after the transmission (step 2), the power supply means 13 supplies power to the amplification means 6 and the reference comparison means 7. (For this predetermined time, the propagation speed of the medium in the flow path and the distance between the sensors are taken into consideration, and the ultrasonic wave is received by the second ultrasonic transducer 3 on the receiving side at about 50.
The time is set such that power is supplied before μs) (step 3).

The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the channel 1 and the second ultrasonic transducer 3
Is amplified by the gain instructed by the control means 12 by the amplification means 6 and output to the reference comparison means 7 and the determination means 8. Here, a state of the received signal after amplification is shown in FIG. That is, as shown in FIG. 2, the reference comparison means 7 compares the output of the amplification means 6 (received signal A) with the reference voltage, and when the magnitude relation is inverted (timing c), the output signal C is output to the determination means 8. Output. The judging means 8 judges that the first negative zero-cross point a at which the sign of the output of the amplifying means 6 after the timing c changes from positive to negative is the arrival point of the ultrasonic wave, and the output signal D is sent to the repeating means 9 and the power supply means 13. Output. The power supply means 13 outputs the output signal D of the determination means 8.
When receiving the signal (step 4), the control means 12 judges the signal regarding the power-off timing set (step 5),
If it is a signal to accelerate the cutoff, the power supplies of the amplification means 6 and the reference comparison means 7 are cut off at the timing of L → H of the output signal D (step 7).

On the contrary, if it is a signal indicating that the cutoff is not advanced, FIG.
After waiting a predetermined time (for example, 10 μs) as indicated by the dotted line (step 6), the power supplies of the amplification means 6 and the reference comparison means 7 are shut off (step 7).

The signal relating to the power-off timing set by the control means 12 to the power supply means 13 is normally turned off immediately after the output of the determination means 8 during the flow rate measurement in which the ultrasonic signal is repeatedly transmitted and received about 350 times. In addition, when the ultrasonic signal is repeatedly transmitted and received several times (for example, eight times) for adjusting the gain of the amplification means 6 after the flow rate measurement, the maximum value of the received wave is included after the output of the determination means 8. As described above, it is set so as to extend and cut off for a predetermined time (10 μs). The output signal D of the judging means 8 is counted by the repeating means 9 and then input to the control means 12.
The control means 12 operates the transmitting means 5 again to transmit the ultrasonic signal from the ultrasonic transducer 2. This series of operations is repeated n times which is set in advance, and the time interval is measured by the time measuring means 10. Then, the first ultrasonic transducer 2 and the second ultrasonic transducer 3 are switched by the switching means 4 and the same operation is performed to measure the respective propagation times of the fluid to be measured from upstream to downstream and from downstream to upstream. Then, based on these time differences, the flow rate calculation means 11 determines the flow rate value in consideration of the size of the flow path and the flow state.

As described above, in the present embodiment, when the flow rate is measured by the instruction of the control means 12, the power supply of the amplification means 6 and the reference comparison means 7 is cut off immediately after the output of the determination means 8, and the gain adjustment of the amplification means 6 is performed thereafter. Sometimes after the output of the judging means 8, a predetermined time (10 μs) so that the maximum value of the received wave is included.
It will be extended and cut off. As a result, the operation times of the amplifying means 6 and the reference comparing means 7 at the time of measurement and at the time of gain adjustment are neglected for a short time of the output period of the determination means 15, the number of repetition times at measurement 350 × power supply time (50
μs) = 17.5 ms, the number of repetitions during gain adjustment is 8
× Power supply time (50 + 10 μs) = 0.48 ms, which is 17.98 ms in total, and the number of repetitions is 350 when power supply control of the power supply means 13 is not performed × power supply time (50 + 10 μs) = a little over 10% compared to 21.0 ms It reduces the operating time of.

Since the total operating time of the amplifying means 6 and the reference comparing means 7 which consume a large amount of current can be shortened in this way, a flow rate measuring device with a reduced operating current can be obtained.

Further, by using a recording medium in which a program for executing the operation of the flow rate measuring apparatus of this embodiment is stored, set values such as a predetermined time of the control means 12 and the power supply means and the number of repetitions of the repeating means 9 can be set. It is possible to flexibly respond to changes, changes in ultrasonic transducers, and changes over time.

(Embodiment 2) FIG. 4 is a flow chart of a second embodiment according to claims 2 and 7 of the present invention. Since the constituent elements of the second embodiment are the same as those of the first embodiment, the description thereof will be omitted.

Regarding the flow rate measuring device configured as described above, the operation of the power supply means 13 different from that of the first embodiment will be described below.
The operation will be described. When the flow rate measurement is started, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the first ultrasonic transducer 2 (steps 21 and 22 in FIG. 4), and when a predetermined time has elapsed (step 23), the power source is turned on. Supplying means 13
Supplies power to the amplification means 6 and the reference comparison means 7.
(This predetermined time is set so that the power is supplied approximately 50 μs before the ultrasonic wave is received by the second ultrasonic transducer 3 on the receiving side, as in the first embodiment) (step 24). .

If the number of repetitions by the repeating means 9 is less than 8 times (step 25), the power supply means 13 is set to not be turned off early (step 27).

The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the flow path 1 and the second ultrasonic transducer 3
Is amplified by the gain instructed by the control means 12 by the amplification means 6 and output to the reference comparison means 7 and the determination means 8. When the arrival time of the ultrasonic waves is determined by the determination means 8, the determination means 8 repeats the means 9 and the power supply means 13.
Is output (step 28).

When the power supply means 13 receives the output from the determination means 8, the power supply is set so that the power supply is not turned off quickly. Therefore, after the elapse of a predetermined time, (step 30) the amplification means 6 and the reference comparison means 7 are set. Power off (step 3)
1).

The output signal of the judging means 8 is counted by the repeating means 9, and the above operation is repeated again unless the preset number of repetitions has been completed (step 21).

When the number of repetitions becomes 9 or more,
The power supply means 13 is set to turn the power supply off early (step 26), and when the power supply means 13 receives the output from the determination means 8, the power supply means 13 does not wait for a predetermined period of time before the amplification means 6 is reached.
Also, the power source of the reference comparison means 7 is shut off (step 3).
1).

As described above, in the present embodiment, the timing at which the power supply means 13 shuts off the power supply to the amplifying means 6 and the reference comparing means 7 can be changed by the number of repetitions of the repeating means 9, so that the number of repetitions of the repeating means 9 is changed. From once to a predetermined number of times, after the power supply means 13 outputs the determination means 8,
The power supply to the amplification means 6 and the reference comparison means 7 is cut off after a predetermined time has passed, and when the number of repetitions exceeds the predetermined time, the power supply to the amplification means 6 and the reference comparison means 7 is cut off without waiting for the predetermined time. . Thereby, the repeating means 9
Power is supplied to the amplifying means 6 and the reference comparing means 7 until the time required for gain adjustment is repeated up to a predetermined number of times, and when the number of repetitions exceeds the predetermined number, the time required for gain adjustment is increased. Since the power of the amplifying means 6 and the reference comparing means 7 is supplied in the minimum time required for the measuring operation, the repeating operation only for the gain adjustment is not necessary, and the amplifying means 6 and the reference comparing with large current consumption are performed. Means 7
The total operation time of can be shortened, and a flow rate measuring device with reduced operating current can be obtained.

Further, by using a recording medium in which a program for executing the operation of the flow rate measuring apparatus of this embodiment is stored, set values such as the predetermined time of the control means 12 and the power supply means and the number of repetitions of the repeating means 9 can be set. It is possible to flexibly respond to changes, changes in ultrasonic transducers, and changes over time.

(Embodiment 3) FIG. 5 is a block diagram of a flow rate measuring apparatus according to a third embodiment of the present invention. FIG. 6 is an operation explanatory diagram of the flow rate measuring apparatus of the third embodiment of the present invention, and illustrates the operation of the timing determination means 14. FIG. 7 is the same flowchart.

In FIG. 5, reference numeral 14 is a timing judging means which is composed of an AD converter and a peak hold circuit, detects the maximum value of the output signal of the amplifying means, and instructs the power supply means 13 that the output timing of the maximum value has passed. is there. The other components are the same as those in the first embodiment, and the description thereof will be omitted.

The operation and action of the flow rate measuring device configured as described above will be described below. When starting the flow rate measurement, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the first ultrasonic transducer 2 (step 4 in FIG. 7).
1). When a predetermined time has passed after the transmission (step 4
2) Power is supplied to the amplifying means 6 and the reference comparing means 7 through the power supply means 13 (this predetermined time is determined by considering the propagation speed and the intersensor distance due to the medium in the flow path, and the second ultrasonic vibration on the receiving side). Approximately 50μ when ultrasonic wave is received by child 3
The time is set such that power is supplied before s) (step 43).

The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the channel 1 and the second ultrasonic transducer 3
Is amplified by the gain instructed by the control means 12 by the amplification means 6 and output to the reference comparison means 7 and the determination means 8. Here, FIG. 6 shows a state of the received signal after amplification. That is, as shown in FIG. 6, the reference comparison means 7 compares the output (received signal A) of the amplification means 6 with the reference voltage, and when the magnitude relationship is inverted (timing c), the output signal C is output to the determination means 8. Output. The judging means 8 judges that the first negative zero-cross point a at which the sign of the output of the amplifying means 6 after the timing c changes from positive to negative is the arrival point of the ultrasonic wave, and the output signal D is sent to the repeating means 9 and the power supply means 13. Output. The power supply means 13 outputs the output signal D of the determination means 8.
When receiving (step 44), timing determination means 14
Waits for output from. The timing determination means 14 is the amplification means 6 during the output period of the reference comparison means 7 (during the L output period).
The output is peak-held, and when the output of the reference comparison unit 7 is completed (output L → H), the peak-held amplitude voltage (V1, V2, V3, ...) Is read by the AD converter. These read amplitude voltages V1, V2 ...
Gradually increases to the maximum value of the received signal (V1 <V
2) Since the maximum value is gradually decreased (V2> V3), the timing determination means 14 outputs a signal (a positive pulse signal shown in FIG. 6) to the power supply means 13 at the time of the decrease (timing e). When the power supply means 13 receives the signal from the timing determination means 14, the power supply of the amplification means 6 and the reference comparison means 7 is cut off (from the output H of the power supply means 13 to L) (step 46).

As described above, in the present embodiment, the timing determination means 14 detects the maximum output value of the amplitude of the received signal and outputs it to the power supply means 13, which then supplies it to the amplification means 6 and the reference comparison means 7. Since the power source is shut off, it is possible to reliably input a signal up to the maximum amplitude value of the received signal used during gain adjustment, and to stop the wasteful operations of the amplifying means 6 and the reference comparing means 7 after the maximum amplitude value. . Since the operating time of the amplifying means 6 and the reference comparing means 7 which consume a large amount of current can be shortened in this way, a flow rate measuring device with a reduced operating current can be obtained.

By using a recording medium in which a program for executing the operation of the flow rate measuring apparatus of this embodiment is stored, the set values such as the predetermined time of the control means 12 and the number of repetitions of the repetition means 9 are changed and ultrasonic waves are transmitted. It can flexibly respond to changes in the oscillator or changes over time.

(Fourth Embodiment) FIG. 8 is a block diagram of a flow rate measuring device according to a fourth embodiment of the present invention. FIG. 9 is an operation explanatory view of the flow rate measuring device of the fourth embodiment of the present invention, and illustrates the operation of the timing determination means 14a. Figure 1
0 is the same flowchart.

In FIG. 8, 14a measures the output signal width of the reference comparing means 7 to detect the maximum value of the output signal of the amplifying means,
It is a timing determination means for instructing the power supply means 13 that the output time of the maximum value has passed. The other components are the same as those in the first embodiment, and the description thereof will be omitted.

Regarding the flow rate measuring device configured as described above, the timing determining means 14a different from the third embodiment will be described below.
The operation and action of will be described. When starting the flow rate measurement, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the first ultrasonic transducer 2 (step 51 in FIG. 10). When a predetermined time has elapsed after the transmission (step 52), power is supplied to the amplification means 6 and the reference comparison means 7 through the power supply means 13 (this predetermined time is the same as the first embodiment and the second ultrasonic vibration on the receiving side is applied). Approximately 50μ when ultrasonic wave is received by child 3
The time is set such that power is supplied before s) (step 53).

The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the flow channel 1 and the second ultrasonic transducer 3
Is amplified by the gain instructed by the control means 12 by the amplification means 6 and output to the reference comparison means 7 and the determination means 8. Here, the state of the received signal after amplification is shown in FIG. That is, as shown in FIG. 9, the reference comparison means 7 compares the output (received signal A) of the amplification means 6 with the reference voltage, and when the magnitude relationship is inverted (timing c), the output signal C is output to the determination means 8. Output. The judging means 8 judges that the first negative zero-cross point a at which the sign of the output of the amplifying means 6 after the timing c changes from positive to negative is the arrival point of the ultrasonic wave, and the output signal D is sent to the repeating means 9 and the power supply means 13. Output. The power supply means 13 outputs the output signal D of the determination means 8.
When receiving (step 54), the timing determination means 14
It waits for output from a. The timing determination means 14 outputs the output signal width of the reference comparison means 7 (W1, W2, W3, ...
・) Is measured. These signal widths W1, W2, ... gradually increase up to the maximum value of the received signal (W1 <W2) and gradually decrease after the maximum value (W2> W3), so when they become short (timing e). The timing determination means 14a outputs a signal (a positive pulse signal shown in FIG. 9) to the power supply means 13. When the signal from the timing determination means 14a is input to the power supply means 13, the power supply to the amplification means 6 and the reference comparison means 7 is cut off (from the output H to L of the power supply means 13) (step 56).

As described above, in the present embodiment, the timing determination means 14a detects the output time of the maximum amplitude value of the received signal and outputs it to the power supply means 13 to supply it to the power supply means 13.
Shuts off the power supply to the amplification means 6 and the reference comparison means 7, so that a signal up to the maximum amplitude value of the received signal used during gain adjustment is surely input, and the unnecessary amplification means 6 and reference comparison after the maximum amplitude value are performed. The operation of the means 7 can be stopped. Since the operating time of the amplifying means 6 and the reference comparing means 7 which consume a large amount of current can be shortened in this way, a flow rate measuring device with a reduced operating current can be obtained.

Further, by using a recording medium in which a program for executing the operation of the flow rate measuring apparatus of this embodiment is stored, the set values such as the predetermined time of the control means 12 and the number of repetitions of the repetition means 9 are changed, and ultrasonic waves are transmitted. It can flexibly respond to changes in the oscillator or changes over time.

(Fifth Embodiment) FIG. 11 is a flow chart of a flow rate measuring apparatus of a fifth embodiment according to claims 5 and 7 of the present invention. The constituent elements of the fifth embodiment are the same as those of the fourth embodiment, and 14a detects the presence or absence of the output signal of the reference comparison means 7 and indicates that the output timing of the maximum value of the output signal of the amplification means has passed. It is a timing determination means for instructing to. FIG. 12 is an operation explanatory view of the flow rate measuring device of the fifth embodiment of the present invention.

Regarding the flow rate measuring device configured as described above, the timing determining means 14a different from the third embodiment will be described below.
The operation and action of will be described. When starting the flow rate measurement, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the first ultrasonic transducer 2 (step 61 in FIG. 11). When a predetermined time has passed after the transmission (step 62), power is supplied to the amplification means 6 and the reference comparison means 7 through the power supply means 13 (this predetermined time is the same as the first embodiment and the second ultrasonic vibration on the receiving side is applied). Approximately 50μ when ultrasonic wave is received by child 3
The time is set such that power is supplied before s) (step 63).

The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the channel 1 and the second ultrasonic transducer 3
Is amplified by the gain instructed by the control means 12 by the amplification means 6 and output to the reference comparison means 7 and the determination means 8. The reference comparing means 7 compares the output of the amplifying means 6 with the reference voltage, and outputs a signal to the judging means 8 at the time when the magnitude relationship is reversed. The judging means 8 outputs the amplifying means 6 after the output of the reference comparing means 7. The first negative zero-cross point at which the sign of the output changes from positive to negative is determined as the arrival point of the ultrasonic wave, and the signal is output to the repeating means 9 and the power supply means 13. When the power supply unit 13 receives the signal output from the determination unit 8 (step 64), it waits for the output from the timing determination unit 14a. The timing determination means 14a detects the presence or absence of the output of the reference comparison means 7. Here, FIG. 12 shows a state of the reference comparison means 7 and the received signal. As shown in FIG. 12, when the received signal is higher than the reference voltage after the output of the judging means 8, the reference comparing means 7 outputs the signal every cycle of the transmission frequency (for example, 2 μS at 500 kHz) (C2 ... C).
Because of 6), if the output of the reference comparison unit 7 disappears even after the time corresponding to one cycle of the transmission frequency has elapsed, the received signal is below the reference voltage. Timing determination means 14
a is the time when the output of the reference comparison means 7 is lost (see FIG. 1).
2 to the power supply means 13 at the timing f) of FIG.
Output the positive pulse signal). Then, when the power supply means 13 receives the signal from the timing determination means 14a, the power supply of the amplification means 6 and the reference comparison means 7 is cut off (from the output H of the power supply means 13 to L) (step 6).
6).

As described above, in the present embodiment, the timing judgment means 14a detects the time when the amplitude of the received signal becomes small and outputs it to the power supply means 13 and the power supply means 13 causes the amplification means 6 and the reference comparison means 7 to operate. Since the power supply to the amplifier is cut off, a signal up to the maximum amplitude of the received signal used during gain adjustment can be surely input, and the unnecessary operations of the amplifying means 6 and the reference comparing means 7 after the maximum amplitude can be stopped. it can. Since the operating time of the amplifying means 6 and the reference comparing means 7 which consume a large amount of current can be shortened in this way, a flow rate measuring device with a reduced operating current can be obtained.

Further, by using a recording medium in which a program for executing the operation of the flow rate measuring apparatus of this embodiment is stored, the set value such as the predetermined time of the control means 12 and the number of repetitions of the repetition means 9 can be changed or ultrasonic waves can be transmitted. It can flexibly respond to changes in the oscillator or changes over time.

(Sixth Embodiment) FIG. 13 is a block diagram of a flow rate measuring apparatus according to a sixth embodiment of claims 6 and 7 of the present invention. FIG. 14 is an operation explanatory view of the flow rate measuring device of the sixth embodiment of the present invention, and FIG. 15 is the same flowchart.

In FIG. 13, 14b counts the number of outputs at an arbitrary point of the output signal of the amplifying means 6 after the signal output from the judging means 8 and supplies power to the effect that the output timing of the maximum value of the output signal of the amplifying means 6 has passed. It is a timing determination means for instructing the means 13. The other components are the same as those in the first embodiment, and the description thereof will be omitted.

Regarding the flow rate measuring device configured as described above, the timing determination means 14b different from the third embodiment will be described below.
The operation and action of will be described. When starting the flow rate measurement, the control means 12 operates the transmitting means 5 to transmit the ultrasonic signal from the first ultrasonic transducer 2 (step 71 in FIG. 15). When a predetermined time has elapsed after the transmission (step 72), power is supplied to the amplification means 6 and the reference comparison means 7 through the power supply means 13. (This predetermined time is approximately 50 when ultrasonic waves are received by the second ultrasonic transducer 3 on the receiving side, as in the first embodiment.
The time is set such that the power is supplied before μs) (step 73).

The ultrasonic signal transmitted from the first ultrasonic transducer 2 propagates in the flow of the channel 1 and the second ultrasonic transducer 3
Is amplified by the gain instructed by the control means 12 by the amplification means 6 and output to the reference comparison means 7 and the determination means 8. The reference comparing means 7 compares the output of the amplifying means 6 with the reference voltage, and outputs a signal to the judging means 8 at the time when the magnitude relationship is reversed. The judging means 8 outputs the amplifying means 6 after the output of the reference comparing means 7. The first negative zero-cross point at which the sign of the output changes from positive to negative is determined as the ultrasonic wave reaching point, and the signal is output to the repeating unit 9, the power supply unit 13, and the timing determining unit 14b. Upon receiving the signal output from the determination means 8, the power supply means 13 waits for the output from the timing determination means 14b (step 74). Here, FIG. 14 shows the state of the reference comparison means 7 and the received signal. 14
As shown in FIG. 5, the timing judgment means 14b is an arbitrary point of the amplification means 6 after the output of the judgment means 8 (for example, a negative zero-cross point a where the sign of the output of the amplification means 6 changes from positive to negative).
2, a3 ...) is counted and set a predetermined number of times (including the maximum value of the received signal, for example, the zero-cross point a
2 to a4 three times) or more), the power supply means 13
To a signal (a positive pulse signal shown in FIG. 14). Then, in the power supply means 13, this timing determination means 14b
When the signal from is input, the amplification means 6 and the reference comparison means 7
Shut off the power supply (from power supply means 13 output H to L)
(Step 76).

As described above, in the present embodiment, the timing determination means 14b counts the number of arbitrary points of the output of the amplification means 6 set in advance, thereby detecting the maximum output value of the amplitude of the received signal and supplying the power. Output to the means 13. As a result, the power supply means 13 shuts off the power supply to the amplification means 6 and the reference comparison means 7, so that signals up to the maximum amplitude value of the received signal used during gain adjustment can be reliably input, and there is no waste after the maximum amplitude value. The operations of the amplification means 6 and the reference comparison means 7 can be stopped. Since the operating time of the amplifying means 6 and the reference comparing means 7 which consume a large amount of current can be shortened in this way, a flow rate measuring device with a reduced operating current can be obtained.

In this embodiment, the timing judgment means 14
The point of the output of the amplifying means 6 counted by b is the negative zero-cross point, but it is not limited to this. For example, it may be a positive zero-cross point or a peak point where the output waveform of the amplifying means 6 changes from rising to falling. Even if set, it has the same effect.

By using a recording medium in which a program for executing the operation of the flow rate measuring apparatus of this embodiment is stored, the set values such as the predetermined time of the control means 12 and the number of repetitions of the repetition means 9 can be changed and ultrasonic waves can be transmitted. It can flexibly respond to changes in the oscillator or changes over time.

[0059]

As described above, claim 1 of the present invention,
In the flow rate measuring device according to the seventh aspect, the timing at which the power supply means shuts off the power supply to the amplification means and the reference comparison means can be changed according to an instruction from the control means. The operating time is reduced because the total operating time of the amplifying means and the reference comparing means, which consumes a large amount of current, can be shortened by setting the time to the minimum required time and setting it to the normal operating time when adjusting the gain with a small number of repetitions. There is an effect that it can be used as a flow rate measuring device.

[Brief description of drawings]

FIG. 1 is a block diagram of a flow rate measuring device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the device.

FIG. 3 is a flowchart of the device.

FIG. 4 is a flowchart of a flow rate measuring device according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a flow rate measuring device according to a third embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the device.

FIG. 7 is a flowchart of the device.

FIG. 8 is a block diagram of a flow rate measuring device according to a fourth embodiment of the present invention.

FIG. 9 is a diagram for explaining the operation of the device.

FIG. 10 is a flowchart of the device.

FIG. 11 is a flowchart of a flow rate measuring device according to a fifth embodiment of the present invention.

FIG. 12 is a view for explaining the operation of the same device.

FIG. 13 is a block diagram of a flow rate measuring device according to a sixth embodiment of the present invention.

FIG. 14 is a view for explaining the operation of the same device.

FIG. 15 is a flowchart of the device.

FIG. 16 is a block diagram of a conventional flow rate measuring device.

FIG. 17 is an operation explanatory diagram of a conventional flow rate measuring device.

FIG. 18 is an operation explanatory view of the amplifying means of the conventional flow rate measuring device.

[Explanation of symbols]

1 flow path 2 First ultrasonic transducer (first transducer) 3 Second ultrasonic transducer (second transducer) 4 switching means 5 Transmission means 6 amplification means 7 Standard comparison means 8 Judgment means 9 Repeating means 10 Timekeeping means 11 Flow rate calculating means 12 Control means 13 Power supply means 14 Timing determination means

Claims (7)

(57) [Claims] 1. A first oscillator and a second oscillator provided in a fluid conduit for transmitting and receiving ultrasonic signals, transmitting means for driving the oscillator, switching means for switching transmission and reception of the oscillator, and Amplifying means for amplifying a received signal of the oscillator, repeating means for transmitting and receiving mutual ultrasonic signals between the oscillators a plurality of times, and flow rate calculating means for calculating a flow rate based on the accumulated time of the ultrasonic signals. A reference comparing means for comparing the output voltage of the amplifying means with a reference voltage, a determining means for determining the arrival time of the ultrasonic signal from the outputs of the reference comparing means and the amplifying means, and the determining means. A flow rate measuring device comprising a power supply means for controlling the power supply to the amplifying means and the reference comparing means after determining the arrival time of the ultrasonic signal by the means. 2. The flow rate measuring device according to claim 1, wherein the power supply means changes the supply timing by a predetermined number of repetitions or more of a plurality of repetitions of transmission and reception of ultrasonic signals by the repetition means. 3. The flow rate measuring device according to claim 1, further comprising a timing determination means for detecting the output timing of the maximum value of the output signal of the amplification means, and the power supply means changing the power supply timing according to the output of the timing determination means. 4. The flow rate measuring device according to claim 3, wherein the timing determination means detects the output timing of the maximum value of the output signal of the amplification means based on the output pulse width of the reference comparison means. 5. The flow rate measuring device according to claim 3, wherein the timing determination means detects the output timing of the maximum value of the output signal of the amplification means based on the presence or absence of the output of the reference comparison means. 6. The timing judgment means is provided after the output of the judgment means.
The flow rate measuring device according to claim 3, wherein the signal is output to the power supply means by the wave number of the output signal from the amplification means in the above. 7. A program for causing a computer to function as all or part of the means of the flow rate measuring device according to claim 1.