JP3422100B2 - 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 using ultrasonic waves.

[0002]

2. Description of the Related Art A conventional flow rate measuring device of this type is shown in FIG.
As shown in FIG.
Is provided opposite to the flow direction, ultrasonic waves are generated from the vibrator 1 in the flow direction, and when the ultrasonic waves are detected by the vibrator 2, the ultrasonic waves are again generated from the vibrator 1, and this is repeated for the time. In contrast, the ultrasonic wave was generated from the vibrator 2 against the flow, the same repetition time was measured, and the velocity of the fluid was calculated from the difference in the times.

[0003]

However, in the above conventional flow rate measuring device, noise is generated in the detection signal due to the reflection of ultrasonic waves between the transducers. That is, first, the ultrasonic signal transmitted from the oscillator 2 reaches the oscillator 3, and when this signal is amplified and compared and detected, the next trigger signal is immediately excited and the second transmission is performed. On the other hand, oscillator 3
The ultrasonic signal reflected by is directed to the transducer 2, and when the second signal reaches the transducer 3 and the trigger of the third signal starts, the first reflected signal reaches. This is because the propagation time of ultrasonic waves is about 500 microseconds, whereas the time for signal amplification and comparison and retrigger is 0.1 microseconds or less, which is extremely short. Therefore, since the reflected wave is received at the time of transmission, it becomes a transmission signal having a disturbed waveform. Further, the reflected signal of the first time is reflected by the vibrator 2 again, goes to the vibrator 3, is superimposed on the transmitted signal of the third time, and reaches the vibrator. The detection signal is affected by these reflected signals and is measured. Since the arrival time of this reflected wave varies depending on the flow velocity in the conduit 1, it receives complicated noise and affects the measurement accuracy, making it difficult to perform high-precision measurement.

The present invention is intended to solve the above problems, and its main purpose is to improve the accuracy of flow rate measurement.

[0005]

In order to achieve the above object, the flow rate measuring device of the present invention has the following configuration.

That is, the transmission / reception is provided in the fluid line.
The first transducer and the second transducer which face each other and transmit and receive ultrasonic signals, and the reception of the transmitted ultrasonic signals are detected.
Delay means for providing a delay time after
Drive the transmission of ultrasonic signals to
A repeating means for performing a plurality of cycles of transmission, delay time elapse, and transmission, and a flow based on the accumulated time of ultrasonic wave propagation.
And a fluid calculation means for calculating the flow rate of the fluid in the body conduit ,
The delay time is the ultrasonic wave transmitted from the oscillator on the transmitting side.
The effect of the ultrasonic signal reflected by the transducer on the receiving side
The configuration is set to reduce the number.

Further , the transmitting / receiving surface is provided in the fluid conduit.
The first transducer and the first transducer that face each other and transmit and receive ultrasonic signals.
After detecting 2 transducers and reception of transmitted ultrasonic signals
Delay means to provide a delay time to the
Transmitting and transmitting sound wave signal, transmitting, ultrasonic wave propagation, receiving,
Repeat the cycle of delay time elapse and outgoing multiple times
Means for transmitting and receiving the first oscillator and the second oscillator.
Switching means for switching, and the cumulative time of the ultrasonic propagation.
And a fluid calculation means for calculating the flow rate of the fluid in the fluid pipeline based on
The delay time is transmitted from the oscillator on the transmitting side.
Ultrasonic signal reflected by the transducer on the receiving side
The configuration is set so as to reduce the effect of. Furthermore
In addition, the delay time depends on the ultrasonic wave transmitted from the oscillator on the transmitting side.
The signal is reflected by the transducer on the receiving side, and the reflected ultrasonic sound
Ultrasonic wave whose wave signal is reflected again by the oscillator on the transmitting side
Signal and the ultrasonic signal transmitted from the oscillator on the transmitting side
The configuration is set so as to reduce the influence.

Time setting means for setting the delay time of the delay means
And a setting variable means for arbitrarily changing the time setting means
And a configuration including. The delay time is when the ultrasonic signal is received.
The configuration is 1.5 times or more. Time setting means is slow
The configuration was such that the delay time was changed randomly.

Transmission and reception is provided in a fluid line through which a fluid flows.
The first transducer and the surfaces that face each other and transmit and receive ultrasonic signals
Flow rate measurement method in a flow rate measurement device equipped with a second oscillator
Is the method of transmitting ultrasonic signals and transmitting ultrasonic signals.
Delay time is set after detecting the reception of the signal
After the transmission of ultrasonic signals, transmission of ultrasonic signals, ultrasonic
Multiple cycles of wave propagation, reception, delay time elapse, and transmission
Repeat several times, based on the cumulative time of ultrasonic wave propagation.
Calculate the flow rate of the fluid in the body duct and
Is the ultrasonic signal transmitted from the oscillator on the transmitting side.
To reduce the effect of ultrasonic signals reflected by the transducer
The configuration is set to.

Transmission / reception provided in a fluid line through which a fluid flows
The first transducer and the surfaces that face each other and transmit and receive ultrasonic signals
Flow rate measurement method in a flow rate measurement device equipped with a second oscillator
Method for transmitting an ultrasonic signal to a fluid line through which a fluid flows
The second ultrasonic oscillator transmits the ultrasonic signal from the oscillator.
And delay after detecting the reception of the ultrasonic signal
A time period is set, and after the delay time,
Sound wave signal transmission, ultrasonic signal transmission, ultrasonic wave propagation,
Repeat the cycle of receiving, delay time elapse, and outgoing multiple times
Return step and transmission between the first vibrator and the second vibrator
The step of switching the reception and performing the series of steps described above;
Based on the cumulative time of ultrasonic propagation obtained from two processes
Calculate the flow rate of the fluid in the fluid line and
During this period, the ultrasonic signal transmitted from the oscillator on the transmitting side is received.
The effect of the ultrasonic signal reflected by the side transducer is reduced.
The configuration is set as follows. Delay time is the vibration of the originating side
The ultrasonic signal transmitted from the child is reflected by the transducer on the receiving side.
The reflected ultrasonic signal is transmitted to the oscillator on the transmitting side.
And the ultrasonic signal reflected again,
Set to reduce the effect on the transmitted ultrasonic signal
It has a different configuration. The delay time can be changed arbitrarily.
It was The delay time is more than 1.5 times the ultrasonic reception signal time.
It has a certain structure.

A configuration in which the delay time is changed randomly
It was

The present invention has the above-mentioned structure and delays repeated ultrasonic wave oscillation to reduce the influence of reflected waves.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a first vibrator 5 that transmits ultrasonic waves and a second vibrator 6 that receives ultrasonic waves are arranged in the flow direction in the middle of the fluid conduit 4. Reference numeral 7 is a transmitting circuit to the first vibrator 5, 8 is an amplifier circuit for a signal received by the second vibrator 6, and the amplified signal is compared with a reference signal by a comparison circuit 9,
When a signal higher than the reference signal is detected, the frequency setting circuit 10
The delay circuit 12 is repeated by the repeater 11 for the number of times set in
After delaying the signal with, the trigger circuit 13 repeatedly transmits the ultrasonic signal. The time when the number of times set by the number-of-times setting circuit 10 is repeated is obtained by the time measuring means 14 such as a timer counter. Next, the switching means 15
Switching the transmission and reception of the oscillator 5 and the second oscillator 6, the second oscillator
An ultrasonic wave signal is transmitted from the vibrator 6 to the first vibrator 5, that is, from the downstream side to the upstream side, and this transmission is repeated as described above to measure the time. Then, from the time difference, the flow rate calculating means 16 obtains the flow rate value in consideration of the size of the pipeline and the flow state.

Next, the transmission / reception signal of the vibrator will be described. FIG. 2 shows a case where the ultrasonic wave signal transmitted from the first vibrator 4 is received by the second vibrator 5. The first oscillator signal burst-transmitted from the first oscillator 4 is received by the second oscillator 5 as the first reception signal, amplified and compared, and is triggered again via the delay circuit 11 to become the second oscillator signal.
On the other hand, a part of the ultrasonic wave of the second oscillator is reflected and travels toward the first oscillator and arrives at the first oscillator, and the second oscillation signal is received and is again transmitted through the delay circuit 11 as the third oscillation signal. There is a difference from the transmission time by about twice the delay time Td of the delay circuit. Further, the first oscillator signal is reflected by the first oscillator 5 and heads for the second oscillator 6, but a time difference of twice the delay time Td is generated from the third received signal which the third oscillator signal reaches. FIG. 3 shows the relationship between transmission and reception when the delay circuit 11 is not provided. The third transmission signal corresponds to the reflected wave of the first transmission signal, and the third reception signal includes the third transmission signal and the first transmission signal. It will overlap with the reflected wave twice. Thereafter, all of the transmissions and receptions repeated the number of times set by the repetition number setting circuit 10 are affected by the reflected wave, and an accurate transmission or reception signal cannot be obtained. If the received signal does not re-trigger unless it exceeds the reference signal, the delay time Td of the delay circuit 11 is at least 1.5 times the time width Tr of the received signal obtained by the burst transmission of ultrasonic waves, so that the influence of the reflected wave will occur. I do not receive it. Although this delay time lengthens the time required for measurement, the ultrasonic wave propagation time is 500 microseconds per time, whereas the delay time is about 20 microseconds, which is not a large delay.

FIG. 4 shows a second embodiment, in which the time of the delay circuit can be arbitrarily changed by the time setting circuit 17, for example, the setting variable circuit can be made proportional to the length of the burst signal or a certain time. As described above, the influence of the periodic noise can be reduced by changing it at random.

FIG. 5 shows a third embodiment of the time counting circuit 14
Signal is used to change the delay time setting of the time setting circuit 17, and the delay time is changed after the repetition is completed and the time is measured, that is, the flow rate is calculated. It is something to measure.

FIG. 6 shows a fourth embodiment, in which the delay time is changed so that the total sum during the repetition of the delay time becomes constant in the total sum setting circuit 19. Delay time is added.

FIG. 7 shows a fifth embodiment. Although the total sum of delay times can be changed, the delay time is equally set for each of the delay times during repetition from upstream to downstream and during repetition from downstream to upstream. To keep them equal.

FIG. 8 shows a sixth embodiment, in which the delay time can be arbitrarily changed by an external setting circuit 21 such as a variable resistor and is adjusted at the time of production of installation work.

FIG. 9 shows a seventh embodiment, in which the delay time is changed according to the value of the flow rate calculating means 16, and when the flow rate is large, it is reflected from the second oscillator 6 and the first oscillator is used. The arrival time of the ultrasonic wave traveling toward 5 is delayed because it travels against the flow, and the delay time may be insufficient. Therefore, the delay time is corrected according to the flow amount. That is, the value of the delay time is increased when the value of the flow rate is large, the value of the delay time is decreased when the value of the flow rate is small, and the relative delay time is kept constant.

As is clear from the above description ,
According to the flow rate measuring device, the following effects can be obtained. (1) Provided in a fluid conduit to transmit and receive ultrasonic signals
1 oscillator and 2nd oscillator, the transmission and reception of the oscillator is switched off
The ultrasonic wave is exchanged between the transducer and the transducer a plurality of times.
Repeating means and delaying signal transmission during said repeating
Calculate the flow rate based on the delay means and the cumulative time of ultrasonic wave transmission.
Since it is equipped with a flow rate calculation means for outputting,
Noise due to reflected signals can be reduced, improving measurement accuracy.
Go up. (2) No. 1 which is provided in the fluid conduit and transmits and receives ultrasonic signals
1 oscillator and 2nd oscillator, the transmission and reception of the oscillator is switched off
The ultrasonic wave is exchanged between the transducer and the transducer a plurality of times.
Repeating means and delaying signal transmission during said repeating
A delay unit and a time setting for setting the delay time of the delay unit.
Setting means and variable setting for arbitrarily changing the time setting means
Calculate the flow rate based on the method and the cumulative time of ultrasonic wave transmission.
Since it has a flow rate calculation means that changes the length of the received signal
Even if you change the delay time, you can prevent noise and vibrate.
It is possible to correspond to the reflected signals other than the child, and the circuit standard
Can be converted. (3) No. 1 which is provided in the fluid conduit and transmits and receives ultrasonic signals
1 oscillator and 2nd oscillator, the transmission and reception of the oscillator is switched off
The ultrasonic wave is exchanged between the transducer and the transducer a plurality of times.
Repeating means and delaying signal transmission during said repeating
Delay means and time to change the delay time at the end of repetition
Calculate the flow rate based on the setting means and the cumulative time of ultrasonic wave transmission.
Since it has a flow rate calculation means to output, there is a delay during repetition
Flow rate based on time measurement as time does not change
The calculation is easy and the error is small. (4) No. 1 which is provided in the fluid conduit and transmits and receives ultrasonic signals
1 oscillator and 2nd oscillator, the transmission and reception of the oscillator is switched off
The ultrasonic wave is exchanged between the transducer and the transducer a plurality of times.
Repeating means and delaying signal transmission during said repeating
A delay unit and a time setting for setting the delay time of the delay unit.
The sum of the delay means during repetition and the constant means becomes a constant value.
Sum setting means for arbitrarily changing the time setting means
And the flow rate based on the cumulative time of ultrasonic wave transmission during repetition
Since it is equipped with a flow rate calculation means for calculating
Delay time can be changed and reflected wave changes over time
And the total sum of delay times is constant.
Therefore, the flow rate calculation based on the timekeeping means is easy and the error is small.
Sai. (5) No. 1 which is provided in the fluid conduit and transmits and receives ultrasonic signals
1 oscillator and 2nd oscillator, the transmission and reception of the oscillator is switched off
The ultrasonic wave is exchanged between the transducer and the transducer a plurality of times.
Repeating means and delaying signal transmission during said repeating
A delay unit and a time setting for setting the delay time of the delay unit.
Fixed means and repeated transmission from upstream to downstream during and after
Each delay during repeated transmission from upstream to upstream
Arbitrary time setting means so that the total time is equal
Equal setting means to change to
Equipped with flow rate calculation means to calculate flow rate based on accumulated time
It is possible to change the delay time during repetition.
It is possible to cope with the temporal fluctuation of the reflected wave and
Total delay time from flow to downstream and from downstream to upstream
When the sum is constant and the time difference is calculated to calculate the flow rate,
Since it is killed, the flow rate calculation is easy and the error is small. (6) No. 1 which is provided in the fluid conduit and transmits and receives ultrasonic signals
1 oscillator and 2nd oscillator, the transmission and reception of the oscillator is switched off
The ultrasonic wave is exchanged between the transducer and the transducer a plurality of times.
Repeating means and delaying signal transmission during said repeating
The delay means and the external setting that can change the setting means from the outside.
Flow rate is calculated based on the fixed means and the cumulative time of ultrasonic wave transmission.
Since it is equipped with a flow rate calculation means for
The delay time setting can be changed and the measurement accuracy is high. (7) Providing ultrasonic signals that are provided in the fluid conduit
1 oscillator and 2nd oscillator, the transmission and reception of the oscillator is switched off
The ultrasonic wave is exchanged between the transducer and the transducer a plurality of times.
Repeating means and delaying signal transmission during said repeating
Calculate the flow rate based on the delay means and the cumulative time of ultrasonic wave transmission.
Depending on the flow rate calculation means to be output and the value of the flow rate calculation means
And a time setting means for setting the delay time of the delay means.
Since it is constant, the reflected wave is constant regardless of the flow rate.
Since the delay is given, the flow rate accuracy is high.

[0022]

Therefore, a highly accurate structure can be obtained.

[Brief description of drawings]

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

FIG. 2 is a waveform diagram of a transmission / reception signal of the device.

FIG. 3 is a waveform diagram of a transmission / reception signal of a conventional flow rate measuring device.

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

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

FIG. 6 is a control block diagram of a flow rate measuring device according to a fourth embodiment of the present invention.

FIG. 7 is a control block diagram of a flow rate measuring device according to a fifth embodiment of the present invention.

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

FIG. 9 is a control block diagram of a flow rate measuring device according to a seventh embodiment of the present invention.

FIG. 10 is a control block diagram of a conventional flow rate measuring device.

[Explanation of symbols]

4 fluid lines 5 First transducer 6 Second oscillator 11 Repeating means 12 Delay means 14 Timekeeping means 15 Switching means 16 Flow rate calculation means 17 hours setting means 18 Setting variable means 19 Sum setting means 20 Equal setting means 21 External setting means

Continuation of the front page (56) Reference JP 59-81515 (JP, A) JP 59-43314 (JP, A) JP 53-93076 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) G01F 1/66 101 G01P 5/00

Claims (12)

(57) [Claims] 1. A transmission line provided on a fluid line and having a relative transmitting / receiving surface.
The first transducer and the second transducer that transmit and receive the ultrasonic signal toward the receiver and the delay after detecting the reception of the transmitted ultrasonic signal
Delay means for providing time, and ultrasonic wave transmission after the delay time.
Signal transmission drive, transmission, ultrasonic wave propagation, reception, delay
Repeating means for performing a plurality of cycles of elapsing and transmitting, and the flow of the fluid pipeline based on the accumulated time of the ultrasonic wave propagation.
And a fluid operation means for calculating the flow rate of the body, during the delay
During this period, the ultrasonic signal transmitted from the oscillator on the transmitting side is received.
The effect of the ultrasonic signal reflected by the side transducer is reduced.
Flow rate measuring device set as described above . 2. A transmission / reception surface which is provided in a fluid line and has a relative surface
First oscillator and second oscillator for transmitting and receiving ultrasonic signals
Delayed after detecting the child and the reception of the transmitted ultrasonic signal
Delay means for providing time, and ultrasonic wave transmission after the delay time.
Signal transmission drive, transmission, ultrasonic wave propagation, reception, delay
Repeating means to repeat the cycle of passing and sending multiple times
And switch the transmission and reception of the first oscillator and the second oscillator.
Switching means for controlling the flow rate of the fluid in the fluid line based on the cumulative time of the ultrasonic wave propagation.
The delay time, which is provided with a fluid calculation means for calculating a flow rate.
Is the ultrasonic signal transmitted from the oscillator on the transmitting side.
To reduce the effect of ultrasonic signals reflected by the transducer
Flow rate measuring device set to . 3. The delay time is transmitted from the oscillator on the transmitting side.
The ultrasonic signal is reflected by the transducer on the receiving side and
The generated ultrasonic signal is reflected again by the oscillator on the transmitting side.
Ultrasonic signal and ultrasonic waves transmitted from the oscillator on the transmitting side
The method according to claim 1, which is set so as to reduce the influence of the signal.
The flow measurement device according to item 2 . 4. A time setting means for setting a delay time of the delay means, the flow rate measuring device according to any one of claims 1-3 that includes a setting changing means for arbitrarily changing the time setting means . 5. The delay time is 1.5 times the ultrasonic reception signal time.
The flow rate measuring device according to any one of claims 1 to 4, wherein the flow rate is double or more. 6. The flow rate measuring device according to claim 3, wherein the time setting means randomly changes the delay time. 7. A transmission / reception device provided in a fluid pipeline through which a fluid flows.
The first transducer and the surfaces that face each other and transmit and receive ultrasonic signals
Flow rate measurement method in a flow rate measurement device equipped with a second oscillator
A method of transmitting an ultrasonic signal, providing a delay time after detecting reception of the transmitted ultrasonic signal, transmitting an ultrasonic signal after the delay time, transmitting an ultrasonic signal, ultrasonic wave The cycle of propagation, reception, delay time elapse, and transmission is repeated multiple times to calculate the flow rate of the fluid in the fluid pipeline based on the cumulative time of ultrasonic wave propagation, and the delay time is transmitted from the oscillator on the transmission side. A flow rate measuring method in which the generated ultrasonic signal is set so as to reduce the influence of the ultrasonic signal reflected by the transducer on the receiving side. 8. A transmission / reception device provided in a fluid pipeline through which a fluid flows.
The first transducer and the surfaces that face each other and transmit and receive ultrasonic signals
Flow rate measurement method in a flow rate measurement device equipped with a second oscillator
Method for transmitting an ultrasonic signal to a fluid line through which a fluid flows
An ultrasonic wave is transmitted from the vibrator, a transmitted ultrasonic signal is received by the second vibrator, a delay time is set after the reception of the ultrasonic signal is detected, and the ultrasonic wave is transmitted from the first vibrator after the delay time. Signal transmission, ultrasonic signal transmission, ultrasonic propagation,
A step of repeating a cycle of receiving, delay time elapse, and transmitting a plurality of times; a step of switching transmission and reception of the first vibrator and the second vibrator to perform the above series of steps;
The flow rate of the fluid in the fluid line is calculated based on the cumulative time of ultrasonic wave propagation obtained from the two steps, and the delay time is the ultrasonic wave signal transmitted from the oscillator on the transmission side when the ultrasonic wave signal on the reception side is transmitted. A flow rate measuring method set so as to reduce the influence of the ultrasonic signal reflected by. 9. The delay time is such that the ultrasonic signal transmitted from the oscillator on the transmitting side is reflected by the oscillator on the receiving side, and the reflected ultrasonic signal is reflected again on the oscillator on the transmitting side. The flow rate measuring method according to claim 7, wherein the flow rate measuring method is set so as to reduce the influence of the ultrasonic signal generated by the transmitter and the ultrasonic signal transmitted from the oscillator on the transmitting side. 10. The flow rate measuring method according to claim 7, wherein the delay time can be changed arbitrarily. 11. The delay time is 1.
The flow rate measuring method according to claim 7, wherein the flow rate is 5 times or more. 12. The flow rate measuring device according to claim 10, wherein the delay time is randomly changed.