JP2000131109A - Flow metering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly and speedily judge a flow rate at an emergency time and improve a safety and a use convenience. SOLUTION: A use state of a fluid is judged from a flow rate obtained at least by a flow rate-operating means 14, and moreover the number of measurement repeat times is set by a repeat-setting means 9 in carrying out measurements. At an abnormal time, an opening means 17 closes a fluid channel 1 to stop the supply of the fluid. Therefore, at an emergency time such as an earthquake or the like, the number of times of repetition is increased to measure the flow rate with a high resolution. Since the use state of the fluid is judged accurately and the supply of the fluid is stopped at the abnormal time, a safety and a use convenience are improved.

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 a flow rate of a gas or the like using an ultrasonic wave.

[0002]

2. Description of the Related Art A conventional flow measuring device of this type is known, for example, from Japanese Patent Application Laid-Open No. 4-328424.
As shown in FIG. 2, ultrasonic vibrators 2 and 3
Is provided in the flow direction, and ultrasonic waves are generated from the vibrator 1 in the flow direction. When the ultrasonic waves are detected by the vibrator 2, the ultrasonic waves are generated again from the vibrator 1, and this operation is repeated. Was measured, and an ultrasonic wave was generated from the vibrator 2 against the flow, and the same repetition time was measured. The speed of the fluid was calculated from the difference between the times.

[0003]

However, in the above-mentioned conventional flow measuring device, the measurement start signal is determined to be a certain frequency or a certain function including a random function. The measurement was performed at the determined sampling frequency. For this reason, power is frequently used, and in the case of battery driving, the battery needs to be replaced within a short period of time, and reduction of power consumption has been a problem.
In order to solve this problem, a method has been proposed in which the measurement cycle is increased as the immediately preceding flow rate is reduced, but the number of repetitions is increased to reduce power consumption while maintaining measurement accuracy.

[0004] However, when such a measuring device is combined with a safety function for stopping the supply of fluid in accordance with the usage of the flow rate, there are the following problems. In other words, since the number of repetitions depends on the immediately preceding flow rate, the determination of the correct flow rate is delayed in an emergency such as an earthquake, and the determination of the supply stop is delayed, or conversely, the supply is stopped when unnecessary. There were problems in terms of safety and user convenience.

[0005] The present invention has been made to solve the above problems, and has as its object to improve safety and usability.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention determines the use condition of the fluid from at least the flow rate obtained by the flow rate calculating means and sets the number of measurement repetitions by the repetition setting means to perform the measurement. In the event of an abnormality, the opening / closing means closes the fluid flow path and stops supplying the fluid.

[0007] Therefore, in an emergency such as an earthquake, the number of repetitions is increased and measurement is performed at a high resolution to accurately judge the use state of the fluid. Improvement of operability and usability can be realized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flow rate measuring apparatus according to a first aspect of the present invention includes a first vibrator and a second vibrator provided in a fluid flow path for transmitting and receiving an ultrasonic signal, and transmitting and receiving the vibrator. Switching means, repetition means for performing ultrasonic transmission between the ultrasonic transducers a plurality of times, time counting means for measuring the accumulated time of ultrasonic propagation, and flow rate calculation for obtaining a flow rate based on the output of the time counting means. Means, a use state determining means for determining the use state of the fluid from at least the flow rate obtained by the flow rate calculating means, a repetition setting means for setting the number of times of the repetition means based on the determination result of the use state determination means, An opening / closing means for closing the fluid flow path in the event of an abnormality based on the determination result of the use state determining means. In the event of an emergency such as an earthquake, the number of repetitions is increased and measurement is performed with high resolution to accurately judge the fluid usage status. In the event of an abnormality, the fluid supply is stopped. Can be improved.

According to a second aspect of the present invention, there is provided a flow measuring device,
The repetition setting means sets the number of repetitions at the time of closing the fluid flow path to be greater than the number of repetitions at the time of opening, and the use state determining means sets the flow rate if the output of the flow rate calculating means at the time of closing the fluid flow path is equal to or more than a predetermined value. A configuration is provided that includes a flow path abnormality determination unit that determines that the path is abnormal. Then, by measuring the flow rate after closing the fluid flow path with high resolution, it is possible to accurately determine the abnormality particularly on the upstream side of the apparatus.

According to a third aspect of the present invention, there is provided a flow measuring device,
When the flow path abnormality determining means determines that there is an abnormality, a notification means is provided for notifying the outside to the outside. Then, after the abnormality is detected, it is possible to prompt the user or the supplier to take appropriate measures by notifying the user to the outside.

According to a fourth aspect of the present invention, there is provided a flow measuring device,
A return means for switching the fluid flow path from closed to open,
The repetition setting means sets the number of repetitions for a predetermined time after the operation of the return means to be greater than the number of repetitions at the time of normal fluid flow path opening, and the use state determination means sets the output of the flow rate calculation means for a predetermined time after the operation of the return means to a predetermined value. If the value is equal to or larger than the value, the configuration is provided with a leakage determination unit that determines that the leakage has occurred. And
By measuring the flow rate after opening the fluid flow path with high resolution, it is possible to accurately determine an abnormality particularly on the downstream side of the apparatus.

According to a fifth aspect of the present invention, there is provided a flow rate measuring device comprising:
When the leak determining means determines that the fluid is leaking, the fluid passage is closed by the opening / closing means. After the leakage is determined, the supply of the fluid can be stopped, so that the safety can be further improved.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In each embodiment, a case where the present invention is applied to a household gas flow rate measuring device will be described.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a flow rate measuring apparatus according to Embodiment 1 of the present invention.

In FIG. 1, a first vibrator 2 for transmitting an ultrasonic wave and a second vibrator 3 for receiving an ultrasonic wave are arranged in the flow direction in the fluid flow path 1. Reference numeral 5 denotes a transmission circuit to the first vibrator 2, and reference numeral 6 denotes an amplifier circuit for a signal received by the second vibrator 3. Reference numeral 7 denotes a comparison circuit that performs signal processing on a received wave that has passed through the amplification circuit 5, and reference numeral 8 denotes a repetition unit that repeatedly performs transmission from the first oscillator 2 and reception by the second oscillator 3 a number of times set by the setting unit 9. Reference numeral 10 denotes a trigger unit for transmitting a transmission trigger signal to the transmission circuit 5, and reference numeral 11 denotes a switching unit for switching between transmission and reception when the number of transmissions and receptions set by the repetition setting unit 9 is completed.

Reference numeral 12 denotes a cycle setting means for setting a series of operation cycles for the repetition means 8 such as repetition of transmission / reception, switching of transmission / reception, and repetition of transmission / reception. Reference numeral 13 denotes a time measuring means for measuring an accumulated time required for repetition of transmission and reception determined by the repetition setting means 8. 14 is a flow rate calculating means for obtaining a fluid flow rate based on the measured value obtained by the time measuring means 13 at each cycle determined by the cycle setting means, 15 is a seismic intensity detecting means for measuring the seismic intensity, and 16 is an output of the flow rate calculating means 14. A use condition judging device for judging the use condition of the fluid from the output of the seismic intensity detecting device 15, and a shut-off valve 17 for closing the fluid flow path 1 and stopping the supply of the fluid when the use condition judging device judges abnormal. Opening and closing means.

The use condition judging means 16 is an emergency closing judging means 18 for judging whether or not the supply of fluid is stopped in an emergency such as when an earthquake occurs, and a flow judging means for judging an abnormality of the flow path system when the fluid flow path 1 is closed. And a road abnormality determining means 19.
Reference numeral 20 denotes a notifying means for notifying the outside when the flow path abnormality determining means determines an abnormality.

Next, the operation and operation will be described. The ultrasonic signal transmitted from the first transducer 2 by the burst signal transmitted from the transmission circuit 5 in response to the signal from the trigger means 10 propagates in the flow, is received by the second transducer 3, Upon reaching the comparison circuit 7, the repetition means 8 triggers the transmission circuit 5 again via the trigger means 10. This repetition is performed the number of times set by the repetition setting means 9, and when the set number of times is reached, the time required for the repetition is measured by the time counting means 13.

After that, the transmission and reception of the first vibrator 2 and the second vibrator 3 are connected in reverse by the switching means 11, and the second
Ultrasonic waves are transmitted from the vibrator 3 toward the first vibrator 2, the arrival time is obtained in the same manner as described above, and a flow rate value is calculated by the flow rate calculating means 14 using these values. The flow rate at one time is measured by the above series of operations, and the measurement operation is performed for each cycle determined by the cycle setting means 12.

Assuming that the sound in the stationary fluid is c and the velocity of the fluid flow is v, if the case where the first vibrator 2 is on the transmitting side is defined as the forward direction, the forward propagation speed is (c + v · cos
θ), if the second oscillator 3 is on the transmission side, and is defined as the reverse direction, the propagation speed in the reverse direction is (cv-cos θ). Assuming that the distance between the transducers 2 and 3 is L, the angle between the ultrasonic wave propagation axis and the center axis of the flow path is θ, and the number of repetitions is n, the repetition times T1 and T1 in the forward and reverse directions, respectively.
2 is: T1 = n · L / (c + v · cos θ) (1) T2 = n · L / (c−v · cos θ) (2) From the equations (1) and (2), v = n · L / 2 cos θ (1 / T1-1 / T2) (3), and if L and θ are known, the flow velocity v can be obtained by measuring T1 and T2.

However, the difference between T1 and T2 is extremely small when the flow velocity is low, and it is difficult to measure accurately. Therefore, by setting the number of times of measurement and averaging, the error is made relatively small and the resolution is increased. ing. From this flow velocity, the flow rate Q is given by: Q = KSV (4) where S is the passage area and K is the correction count.

The emergency closing judging means 18 in the usage judging means 16 determines whether the gas usage is normal, caution required, or abnormal based on the output results of the flow rate calculating means 14 and the seismic intensity detecting means 15.
Determine which of the states it is. For example, if the seismic intensity is 3 or less depending on the strength, it is determined that a warning is required if the intensity is 4 or more. That is, if gas is used under the condition of a predetermined seismic intensity or higher, there is a possibility that a gas appliance or a piping accident may occur, and therefore it is considered necessary to immediately stop gas supply.

Therefore, in the case of a situation requiring caution, the number of measurement repetitions determined by the repetition setting means 9 is set to be larger than that of the repetition setting means 9 so that high resolution can be maintained even with a small flow rate. Do. If the output of the flow rate calculating means 14 exceeds a predetermined value, the opening / closing means 1
7, the fluid flow path 1 is closed, and the supply of gas is stopped.
Next, an operation after the supply of gas is stopped will be described. Even after the opening / closing means 17 is operated, the failure of the opening / closing means 17 and the damage / damage of the fluid flow path 1 due to the impact at the time of the earthquake.
When deformation or the like occurs, the gas may continue to flow. In such a case, even if it is very small, it is necessary to take immediate action if the gas flow rate is recognized. Therefore, the number of measurement repetitions determined by the repetition setting means 9 is subsequently larger than in the normal state, that is, when the flow path is opened. Continue the measurement.

In such a situation, if the output of the flow rate calculating means 14 exceeds a predetermined value, the flow path abnormality means 19 determines that the flow path is abnormal, and outputs a closing signal to the opening / closing means 17 again. However, when the opening / closing means 17 fails, the gas supply cannot be stopped. Therefore, the notification means 20 notifies the user and the gas supplier, for example. As a result, the occurrence of an accident can be prevented by taking appropriate measures such as stopping supply at a further upstream side of the flow rate measuring device.

(Embodiment 2) FIG. 2 is a block diagram showing a configuration of a flow rate measuring apparatus according to Embodiment 2 of the present invention.

The second embodiment is different from the first embodiment in that a return means 21 is provided for reopening the fluid flow path 1 after the fluid flow path 1 has been closed. After a predetermined time, the number of measurement repetitions determined by the repetition setting means 9 is set to be larger than that at the time of opening the normal fluid flow path.
During this period, if there is a flow rate equal to or more than a predetermined value, a leak detection unit 22 that determines that there is a leak is provided. Further, if the leak determination unit 22 determines that there is a leak, the fluid flow path is closed again. is there.

The components having the same reference numerals as those in the first embodiment have the same structure, and a description thereof will be omitted. After the fluid flow path 1 is closed by the opening / closing means 17 and the supply of gas is stopped, the user or a gas supplier closes the main valve of the gas appliance (not shown) on the downstream side of the apparatus, and closes the piping path. After taking necessary measures such as inspection, the return means 21 such as a switch is operated to give an instruction to the opening / closing means 17 to open the fluid flow path 1. At this time, there is a case where the gas continues to flow due to an abnormality at the downstream side of the opening / closing means 17 such as damage to instruments and piping due to an impact at the time of an earthquake, oversight at the time of inspection, and the like.

In such a case, even if the gas flow rate is small, it is necessary to take immediate action even if the gas flow rate is small. Continue. In such a situation, if the output of the flow rate calculating means 14 exceeds a predetermined value, the leak determining means 22 determines that there is a leak and notifies the outside through the notifying means 19. If it is determined that there is a leak, the supply of gas is stopped again by the opening / closing means 17 to further enhance safety.

[0029]

As is apparent from the above description, the flow rate measuring device according to the first aspect of the present invention determines the use condition of the fluid from at least the flow rate obtained by the flow rate calculating means and determines the number of times of measurement repeated by the repeat setting means. Is set and measurement is performed, and the opening / closing means closes the fluid flow path when abnormal, and opens the fluid flow path when normal. Therefore, in the event of an emergency such as an earthquake, the number of repetitions is increased and measurement is performed with high resolution to accurately judge the fluid usage status. In the event of an abnormality, the supply of fluid is stopped. In addition, the flow measurement device according to claim 2 of the present invention increases the number of measurement repetitions in a state in which the fluid supply is stopped after the abnormality is determined, and performs measurement with high resolution. Abnormality can be determined with high accuracy.

The flow rate measuring device according to claim 3 of the present invention is
If the flow rate when the fluid flow path is closed is equal to or higher than a predetermined value, the alarm is notified.After detecting the abnormality, the alarm is notified to the user or the supplier to take appropriate measures. Can be encouraged.

The flow rate measuring device according to claim 4 of the present invention is
After the abnormality determination, the number of measurement repetitions is increased in a state in which the fluid supply can be restarted, and the measurement is performed with high resolution, whereby it is possible to accurately determine a leak particularly on the downstream side of the apparatus.

According to a fifth aspect of the present invention, there is provided a flow rate measuring device comprising:
If there is a leak, the fluid supply is stopped again, so that safety can be further improved.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a flow measurement device according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a conventional flow measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fluid flow path 2 1st oscillator 3 2nd oscillator 8 Repetition means 9 Repetition setting means 11 Switching means 13 Clocking means 14 Flow rate calculation means 15 Seismic intensity detection means 16 Usage state determination means 17 Opening / closing means 19 Flow path abnormality determination means 20 Notification means 21 Return means 22 Leakage determination means

Claims (5)

[Claims] A first vibrator and a second vibrator provided in a fluid flow path for transmitting and receiving an ultrasonic signal; switching means for transmitting and receiving the vibrator; and mutual ultrasonic waves between the ultrasonic vibrators. Repeating means for performing transmission a plurality of times, time measuring means for measuring the cumulative time of ultrasonic propagation, flow rate calculating means for obtaining a flow rate based on the output of the time counting means, and at least the flow rate of the fluid from the flow rate determined by the flow rate calculating means A use condition judging device for judging a use condition, a repetition setting device for setting the number of times of the repetition device based on the judgment result of the use condition judging device, and a fluid flow path in an abnormal state based on the judgment result of the use condition judging device. A flow measuring device comprising: an opening / closing means for closing. The repetition setting means sets the number of repetitions at the time of closing the fluid flow path to be greater than the number of repetitions at the time of opening, and the use state determining means sets the output of the flow rate calculating means at the time of closing the fluid flow path to a predetermined value. 2. The flow rate measuring device according to claim 1, further comprising a flow path abnormality determining unit that determines that the flow path is abnormal. 3. The flow rate measuring device according to claim 2, further comprising a notifying means for notifying the outside when the flow path abnormality judging means judges an abnormality. A return means for switching the fluid flow path from a closed state to an open state, wherein the repetition setting means sets the number of repetitions for a predetermined time after the operation of the return means to be greater than the number of repetitions at the time of opening the normal fluid flow path; 3. The flow rate measuring device according to claim 2, wherein the situation determining means includes a leak determining means for determining a leak if the output of the flow rate calculating means for a predetermined time after the operation of the return means is equal to or more than a predetermined value. 5. The flow rate measuring device according to claim 4, wherein when the leak judging means judges that there is a leak, the fluid passage is closed by the opening / closing means.