JP2002365104A - Ultrasonic type vortex flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent delay of detection of change in pressure accompanied with occurrence of Karman vortexes by difference in length of a guiding paths. SOLUTION: In this ultrasonic type vortex flowmeter 70, a pair of passages 18A, 20A for propagation of ultrasonic waves, which penetrate in the extending direction of a body 16A for generating the vortexes, are arranged in side by side in the flowing direction (upstream and downstream sides) of fluid to be measured. In one ends of the passages 18A, 20A for the propagation of the ultrasonic waves, ultrasonic sensors for transmitting are opposed. In the other ends of the passages 18A, 20A for the propagation of the ultrasonic waves, ultrasonic sensors for receiving are opposed. Since total length of inlet and outlet holes 22A, 24A, 26A, 28A for the fluid are the same, timing of inflow when the fluid to be measured flows in from the inlet and outlet holes 22A, 26A for the fluid to the passages 18A, 20A for the propagation of the ultrasonic waves are the same as the timing of the inflow when the fluid to be measured flows in from the inlet and outlet holes 24A, 28A for the fluid to the passages 18A, 20A for the propagation of the ultrasonic waves. It is, therefore, possible to prevent increase in instrumental errors by the delay of the detection of the Karman vortexes 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic eddy flow meter, and more particularly to an ultrasonic eddy flow meter for measuring a flow rate of a gas as a fluid to be measured using an ultrasonic sensor.

[0002]

2. Description of the Related Art Generally, in a conventional ultrasonic vortex flowmeter,
A vortex generator is formed extending in a direction perpendicular to the flow direction in a flow path in which the fluid to be measured flows, and one or two sets of ultrasonic sensors are provided downstream of the vortex generator to form a vortex generator. It is configured to detect Karman vortices generated downstream. 1
A pair of ultrasonic sensors are provided in the flow path so as to face each other, and one is a transmitting side that transmits ultrasonic waves,
The other side is a receiving side that receives the ultrasonic wave propagated in the fluid to be measured.

[0003] In this type of ultrasonic vortex flowmeter, the phase modulation that the ultrasonic wave receives from the fluid to be measured is detected, and the flow rate of the fluid to be measured is obtained from the amount of phase modulation. Fluid sound speed changes (adiabatic compression) due to temperature changes and pressure pulsations reduce measurement errors due to erroneous flow rate measurements.

Further, by comparing the amount of phase modulation detected by each of the two sets of ultrasonic sensors, a change in fluid sound velocity (adiabatic compression) due to temperature change or pressure pulsation affecting phase modulation is canceled. Sonic vortex flowmeters also exist. Here, this type of ultrasonic vortex flowmeter will be described in more detail.

[0005] This type of ultrasonic vortex flowmeter includes a flowmeter body having a flow path through which a fluid to be measured is formed, a vortex generator provided in the flow path at right angles to the flow direction, and a vortex generator. A plurality of first passages extending in the longitudinal direction of the generator, an ultrasonic sensor provided in each of the plurality of first passages, and detecting a flow of a fluid to be measured flowing in each of the first passages; And a pair of second passages that are provided in each of the first passages and communicate the respective first passages with the side wall of the vortex generator. It is configured to receive the phase modulation in the direction, and by comparing the phases of the ultrasonic waves subjected to the phase modulation obtained by the respective ultrasonic sensors, the occurrence of the alternately generated Karman vortex is detected. This cancels out the disturbances that the two ultrasonic sensors receive in the same phase, such as temperature change and pulsation of the fluid to be measured.

Next, an ultrasonic vortex flowmeter according to the above-mentioned conventional technique will be described with reference to FIGS.

FIG. 14 is a configuration diagram showing an example of a conventional ultrasonic vortex flowmeter. FIG. 15 is a longitudinal sectional view taken along line AA in FIG.

As shown in FIGS. 14 and 15, an ultrasonic vortex flowmeter 10 has a flowmeter main body 14 having a flow path 12 through which city gas as a fluid to be measured flows, and a flowmeter main body 14.
And a vortex generator 16 extending in a vertical direction perpendicular to the flow direction of the fluid to be measured (indicated by an arrow in FIG. 14) in the flow path 12 of FIG. The vortex generator 16 has a substantially trapezoidal cross section when viewed from the axial direction.

In the process in which the fluid to be measured flows to the downstream side while the fluid to be measured collides with the front surface 16a of the vortex generator 16 facing the upstream side, Karman vortices 17 are generated alternately on the right and left downstream of the vortex generator 16. Since the cycle in which the Karman vortex is generated is proportional to the flow velocity of the measured fluid, the flow rate of the measured fluid can be obtained by detecting the frequency of the Karman vortex generated in the measured fluid.

The vortex generator 16 penetrates a pair of ultrasonic propagation paths (first paths) 18 and 20 arranged in a direction perpendicular to the flow direction of the fluid to be measured so as to extend in the longitudinal direction. . The ultrasonic wave propagation paths 18 and 20 are respectively provided in the vortex generator 1
6 are communicated with first to fourth fluid inlet / outlet ports 22, 24, 26, 28 which open on the slopes 16b, 16c formed on the downstream side.

Since the ultrasonic wave propagation passages 18 and 20 are arranged in a direction orthogonal to the flow direction of the fluid to be measured, each of the fluid inlet / outlet (pressure introducing holes) 22, 24, 26 and 28 (second passage) ) Are shifted in the longitudinal direction (height direction) of the vortex generator 16 and are provided so as not to cross each other. Further, the fluid inlet / outlet holes 22 and 24 have a long overall length (La) from the ultrasonic wave propagation passages 18 and 20 to the slopes 16b and 16c, and the fluid inlet / outlet holes 26 and 28 extend from the ultrasonic wave propagation passages 18 and 20 respectively. The entire length until opening on the slopes 16b, 16c is short (Lb) (La> L).
b).

One end of the first fluid inlet / outlet port 22 has an inclined surface 16.
b, and the other end is communicated with the ultrasonic wave propagation path 18. The second fluid inlet / outlet port 24 has one end formed with a slope 16c.
The other end is communicated with the ultrasonic wave propagation path 20. In addition, the third fluid inlet / outlet 26 has one end formed with the slope 16b.
The other end is communicated with the ultrasonic wave propagation path 20. Further, one end of the fourth fluid inlet / outlet hole 28 has a slope 16c.
The other end is communicated with the ultrasonic wave propagation path 18.

Therefore, when a Karman vortex is generated in the fluid to be measured flowing downstream of the vortex generator 16, a pressure difference occurs on both the left and right sides of the vortex generator 16 due to a pressure change accompanying the generation of the Karman vortex. As a result, a flow of the fluid to be measured (shown by a broken line in FIG. 14) occurs in the ultrasonic wave propagation passages 18 and 20 extending in the axial direction. That is, the ultrasonic wave propagation paths 18 and 2
In 0, a flow in the opposite direction occurs alternately at the same cycle as the generation of the Karman vortex.

As described above, in the prior art, since the ultrasonic wave propagation passages 18 and 20 are arranged in the direction orthogonal to the flow direction of the fluid to be measured, the fluid inlet / outlet holes 22 and 24 and the fluid inlet / outlet 2
6 and 28 cannot have the same total length, and the time required for inflow and discharge of the fluid to be measured when Karman vortices are generated alternately on both sides of the vortex generator 16 is different.

At the upper and lower ends of the vortex generator 16, holding members 38 and 40 for holding the transmitting ultrasonic sensors 30 and 32 and the receiving ultrasonic sensors 34 and 36 are provided. Each ultrasonic sensor 30, 32, 34, 36
Mounting holes 38a, 38 provided in holding members 38, 40
b, 40a, 40b.

The mounting holes 38a, 38b, 40a, 40b into which the ultrasonic sensors 30, 32, 34, 36 are inserted,
It communicates with the openings at both ends of the ultrasonic wave propagation paths 18 and 20.
The ultrasonic waves transmitted from the transmission ultrasonic sensors 30 and 32 propagate through the fluid in the ultrasonic propagation paths 18 and 20 and are received by the reception ultrasonic sensors 34 and 36. At this time, the ultrasonic waves propagating in the ultrasonic wave propagation paths 18 and 20 flow at a velocity of the fluid to be measured flowing in the ultrasonic wave propagation paths 18 and 20 due to the pressure difference between the upper and lower sides of the vortex generator 16 due to the generation of the Karman vortex. Is modulated by Therefore, the receiving ultrasonic sensor 3
The detection signal output from each of the channels 4 and 36 is demodulated to detect the generation frequency of the Karman vortex.
The flow rate of the fluid to be measured flowing through the inside can be measured.

The transmission ultrasonic sensors 30 and 32 are connected to an oscillation circuit 46 and vibrate by signals from the oscillation circuit 46 to transmit ultrasonic waves into the fluid in the ultrasonic propagation paths 18 and 20. Then, the ultrasonic waves propagated in the ultrasonic wave propagation paths 18 and 20 are received by the receiving ultrasonic sensors 34 and 36. Further, the receiving ultrasonic sensors 34 and 36 are connected to a calculation unit 47 that calculates a flow rate.

The operation section 47 has amplifier circuits 48 and 50, waveform shaping circuits 52 and 54, a phase comparison circuit 56, a flow rate operation circuit 62, a display circuit 64, and an output circuit 66. In the flow rate calculation circuit 62, the flow rate of the fluid to be measured flowing through the flow path 12 is determined based on the frequency of the Karman vortex obtained from the phase difference between the detection signals output from the receiving ultrasonic sensors 34 and 36 as described later. Is calculated.

[0019]

However, in the conventional ultrasonic vortex flowmeter constructed as described above, the total length of the fluid inlet / outlet ports 22 and 24 is short (Lb), and the fluid inlet / outlet port 2
Since the total length of 6, 28 is long (La), when the measured fluid flows into the fluid inlet / outlet holes 22 and 26 opened on the upper surface side of the vortex generator 16 due to the generation of Karman vortex,
There is a problem that a time delay occurs in the fluid inlet / outlet port 26 having a long overall length due to the difference in the total length between the fluid inlet / outlet ports 22 and 26.

Therefore, conventionally, the positions of the fluid inlet / outlet ports 22, 24, 26, and 28 opened on the side surface of the vortex generator cannot be symmetrically arranged with respect to the center of the flow path 12, so that the flow path There is a possibility that the modulation amount varies due to the difference in the flow velocity distribution inside 12, thereby causing the instrumental difference to worsen.

Further, the two ultrasonic wave propagation paths 18 and 20
In the ultrasonic type vortex flow meter of the type in which the phase modulation amount is obtained by comparing the detected values detected by the above, there is a shift in the detection generation timing of the vortex inside the two ultrasonic propagation paths 18 and 20. The deviation affects the amount of phase modulation, which results in a measurement error of the flow rate.

Accordingly, an object of the present invention is to provide an ultrasonic vortex flowmeter which has solved the above-mentioned problems.

[0023]

In order to solve the above problems, the present invention has the following features.

According to the first aspect of the present invention, there is provided a flow meter body having a flow path through which a fluid to be measured is formed, a vortex generator provided in the flow path so as to be orthogonal to the flow direction, and a vortex generator. A plurality of first passages extending in the longitudinal direction of each of the plurality of first passages; an ultrasonic sensor provided in each of the plurality of first passages for detecting a flow of a fluid to be measured flowing in each of the first passages; A plurality of first passages in an ultrasonic vortex flowmeter provided in each of the first passages and having a pair of second passages communicating with the first passages and the side wall of the vortex generator. It is provided so as to be located on the upstream side and the downstream side in the flow direction of the fluid measurement fluid,
Since the entire lengths of the second passages can all be the same size, the generation timing of the alternating flow inside the plurality of passages becomes the same, and the detection deviation of the Karman vortex due to the plurality of passages over time can be eliminated. It is possible to prevent an instrumental difference from being deteriorated due to a difference in flow velocity distribution inside the plurality of passages.

According to a second aspect of the present invention, both lengths of the pair of second passages communicating with the first passage are set to the same length, and the length of the fluid to be measured flowing into or out of the second passage is adjusted. The transit time becomes the same, and the detection delay of the Karman vortex detected by the pair of ultrasonic sensors can be eliminated.

According to a third aspect of the present invention, a pair of second passages communicating with one of the plurality of first passages and a pair of second passages communicating with the other first passage are formed by a vortex. It is provided on the same plane in the longitudinal direction of the generator, and the distance in the first passage through which the fluid to be measured flows in or out of the second passage is the same, and a pair of ultrasonic modulation conditions is set. The measurement accuracy can be improved with the same ultrasonic sensor.

According to a fourth aspect of the present invention, there is provided a phase comparing means for comparing a phase difference between respective detection signals output from a plurality of ultrasonic sensors for detecting a flow of a fluid to be measured flowing through a plurality of first passages. And a flow rate calculating means for calculating the flow rate of the fluid to be measured from the phase comparison result by the phase comparing means,
It is possible to cancel disturbance that both ultrasonic sensors receive in the same phase, such as temperature change and pulsation of the fluid to be measured. Therefore, the phase modulation signal (vortex signal) obtained when the phases are compared changes sinusoidally, which can reduce the superposition of noise, prevent the loss of the vortex detection pulse, and measure at the time of low flow rate measurement. Sensitivity can be improved.

[0028]

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

FIG. 1 is a block diagram of a first embodiment of an ultrasonic vortex flowmeter according to the present invention. FIG. 2 is a longitudinal sectional view taken along line BB in FIG. FIG. 3 is a cross-sectional view taken along line CC in FIG. 1 to 3, the same parts as those in FIGS. 14 and 15 described above are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 1 to 3, in the ultrasonic vortex flowmeter 70, a pair of ultrasonic propagation paths (first paths) 18A and 20A penetrating in the extending direction of the vortex generator 16A are provided. They are arranged so as to line up in the flow direction (upstream and downstream) of the fluid to be measured. That is, one ultrasonic wave propagation path 18A is located on the upstream side close to the front surface 16a, and the other ultrasonic wave propagation path 20A is located on the downstream side separated from the front surface 16a.

Therefore, the transmitting ultrasonic sensors 30A and 32A face one end of the ultrasonic propagation paths 18A and 20A, and the receiving ultrasonic sensor 34A faces the other ends of the ultrasonic propagation paths 18A and 20A. , 36A face each other. The ultrasonic sensors 30A, 32A and 34A, 36A are provided with mounting holes 38a, 38b, 40a, 4 of the holding members 38A, 40A.
0b communicates with the ends of the ultrasonic wave propagation paths 18A and 20A from the extending direction, respectively.
The ultrasonic wave transmitted from 32A is transmitted through the ultrasonic wave propagation path 18A,
It is provided so as to travel straight through 20A and reach the ultrasonic sensors 34A and 36A. Therefore, the ultrasonic sensor 3
The ultrasonic waves transmitted from 0, 32 are transmitted through the ultrasonic propagation path 18.
A and 20A are less susceptible to noise when reflected on the inner wall. The operation unit 47A of the first embodiment has the same configuration as the operation unit 47 described above.

FIG. 4 is a longitudinal sectional view of the vortex generator 16A of the first embodiment viewed from the downstream side. FIG. 5 is a longitudinal sectional view taken along line DD in FIG. FIG. 6 is a longitudinal sectional view taken along line EE in FIG. As shown in FIGS. 4 and 5, the vortex generator 1
6A, the ultrasonic propagation paths 18A, 20A
The fluid inlet / outlet ports 26, 28 communicating with the slopes 16b, 1
6c. Ultrasonic propagation path 18
Since A and 20A are arranged in the flow direction of the fluid to be measured on the center line O of the vortex generator 16A, they are provided at positions where the distances to the openings of the slopes 16b and 16c are equal. Therefore, the fluid inlet / outlet holes 26 and 28 are
A, 20A to the slopes 16b, 16c (L3 =
L4) have the same dimensions.

As shown in FIGS. 4 and 6, in the EE section of the vortex generator 16A, the ultrasonic wave propagation paths 18A and 20A are formed.
The fluid inlet / outlet ports 22A and 24A communicating with the slope A
b, 16c. Since the ultrasonic propagation paths 18A and 20A are arranged in the flow direction of the fluid to be measured, they are provided at positions where the distances to the openings of the slopes 16b and 16c are equal. Therefore, the fluid inlet / outlet 22A,
24A extends from the ultrasonic propagation paths 18A and 20A to the slope 16
The total length (L1 = L2) up to b and 16c is the same.

As described above, the fluid inlet / outlet ports 22A, 24A,
26A and 28A have the same overall length (L1 = L2 = L3 =
L4), the fluid inlet / outlet 22A and the fluid inlet / outlet 26A when detecting the pressure change accompanying the generation of the Karman vortex 17
The inflow timing of the fluid to be measured flowing into the ultrasonic wave propagation passages 18A and 20A from the air, and the inflow timing of the fluid to be measured flowing into the ultrasonic wave propagation passages 18A and 20A from the fluid inlet / outlet 24A and the fluid inlet / outlet 28A coincide with each other. The detection delay of the vortex 17 can be eliminated.

Thus, a plurality of passages (fluid inlet / outlet 22
A and 26A, 24A and 28A) have the same alternating flow generation timing, and a plurality of passages (fluid inlet / outlet 2
2A, 24A, 26A, 28A) can eliminate the temporal detection deviation of the Karman vortex. As a result, the plurality of passages (fluid inlet / outlet holes 22A, 24A, 26A, 28
A) It is possible to prevent the instrumental difference from being deteriorated due to the difference in the internal flow velocity distribution, and to further improve the flow rate measurement accuracy.

When measuring the flow rate, the receiving ultrasonic sensor 34
A, 36A detects an alternating flow accompanying the generation of the Karman vortex 17 in the ultrasonic propagation paths 18A, 20A, and compares the detection signals output from the receiving ultrasonic sensors 34A, 36A, thereby measuring the measured signal. The flow rate can be obtained while canceling disturbances such as temperature change and pulsation of the fluid. Therefore, the phase difference between the signals output from the receiving ultrasonic sensors 34A and 36A is compared to cancel the sound speed change due to the disturbance received in the same manner, and the fluid sound speed change due to the pressure pulsation in the flow path 12 (adiabatic compression). Erroneous measurement due to the influence of can be prevented.

The fluid inlet / outlet ports 22A, 24A, 26
A, 28A have the same overall length (L1 = L2 = L3 =
L4), the two ultrasonic propagation paths 18A, 2A
Since the timing of fluctuations inside the 0A becomes the same, each phase difference output changes sinusoidally, and noise is not superimposed, so that the eddy detection pulse can be prevented from being lost and the measurement sensitivity at the time of low flow rate measurement is improved. Can be done.

Next, an ultrasonic vortex flow meter 80 according to a second embodiment will be described. FIG. 7 is a longitudinal sectional view of the vortex generator 16B of the second embodiment viewed from the downstream side. FIG. 8 is a longitudinal sectional view taken along line FF in FIG. FIG. 9 is a longitudinal sectional view taken along line GG in FIG.

As shown in FIGS. 7 and 8, in the FF cross section of the vortex generator 16B, the ultrasonic wave propagation paths 18B and 20B are formed.
Fluid inlet / outlet holes 26B and 28B communicating with B are formed at different angles toward the inclined surface 16b. Since the ultrasonic wave propagation paths 18A and 20A are arranged in the flow direction of the fluid to be measured on the center line O of the vortex generator 16B, they are provided at positions where the distances to the opening of the slope 16b are equal. Therefore, the fluid inlet / outlet holes 26B, 28B are formed in a V-shape,
It is formed so as to intersect and communicate with the slope 16b,
The total length (L3 = L4) from the ultrasonic wave propagation paths 18B and 20B to the slope 16b is the same.

As shown in FIGS. 7 and 9, in the GG section of the vortex generator 16B, the ultrasonic wave propagation paths 18B and 20B are formed.
Fluid inlet / outlet holes 22B and 24B communicating with B are formed at different angles toward the slope 16c. Since the ultrasonic wave propagation paths 18B and 20B are arranged in the flow direction of the fluid to be measured, they are provided at positions where the distances to the opening of the slope 16c are equal. Therefore, the fluid inlet / outlet holes 22B, 24B
Are formed in a V-shape and are formed so as to intersect and communicate with each other on the inclined surface 16c, and the ultrasonic wave propagation paths 18B and 20B
To the slope 16c (L1 = L2) have the same dimensions.

Therefore, as in the first embodiment, the total length of the fluid inlet / outlet ports 22A, 24A, 26A, 28A is the same (L1 = L2 = L3 = L4).
When detecting the pressure change accompanying the occurrence of
A from the fluid inlet / outlet 26A and the ultrasonic propagation passages 18A, 20A.
A, the inflow timing of the fluid to be measured flowing into A, and the ultrasonic transmission path 18 from the fluid inlet / outlet 24A and the fluid inlet / outlet 28A.
The detection timing of the Karman vortex 17 can be eliminated by matching the inflow timings of the fluids to be measured flowing into the A and 20A. Thereby, stable detection of the Karman vortex 17 can be performed.

Next, an ultrasonic vortex flowmeter 90 according to a third embodiment will be described. FIG. 10 shows a vortex generator 16C of the third embodiment.
FIG. 3 is a longitudinal sectional view of the device viewed from the downstream side. FIG. 11 shows H in FIG.
It is a longitudinal cross-sectional view which follows the -H line. FIG. 12 is a sectional view taken along a line II in FIG.
It is a longitudinal cross-sectional view along a line.

As shown in FIGS. 10 and 11, in the HH section of the vortex generator 16C, the ultrasonic wave propagation paths 18C,
Fluid inlet / outlet ports 26C, 28C communicating with 20C are formed toward the slopes 16b, 16c, respectively. The ultrasonic propagation paths 18C and 20C constitute individual flow meters, and do not cancel two sets of sensor outputs, but are provided with two ordinary ultrasonic vortex flow meters. is there.

The ultrasonic propagation paths 18C and 20C are
Although they are arranged in the direction of flow of the fluid to be measured on the center line O of the vortex generator 16B, the respective lengths of the fluid inlet / outlet ports 26C and 28C are different (L3 ≠ L) because they constitute independent measurement paths.
4).

As shown in FIGS. 10 and 12, in the II section of the vortex generator 16B, the ultrasonic wave propagation paths 18C,
Fluid inlet / outlet ports 22C and 24C communicating with 20C are formed toward slopes 16b and 16c, respectively. Note that the fluid inlet / outlet holes 22C and 24C have different overall lengths (L1２L2) as in the above-mentioned HH section.

The total length of the fluid inlet / outlet ports 22C and 28C connected to the ultrasonic wave propagation path 18C is the same (L1 = L
4), and the total length of the fluid inlet / outlet ports 24C and 26C communicated with the ultrasonic wave propagation path 20C is the same (L2 = L3).

Therefore, in the ultrasonic wave propagation passage 18C and the ultrasonic wave propagation passage 20C, the fluid inlet / outlet holes 22C, 28C and the fluid inlet / outlet hole 24 communicated with the slopes 16b, 16c, respectively.
Since the total lengths of C and 26C are equal, a delay in the Karman vortex detection operation due to the difference in the total length does not occur in each of the ultrasonic propagation paths 18C and 20C.

FIG. 13 shows an ultrasonic vortex flowmeter 9 according to the third embodiment.
FIG. As shown in FIG. 13, in the ultrasonic vortex flowmeter 90, a pair of ultrasonic propagation paths 18C and 20C penetrating in the extending direction of the vortex generator 16C extend in the flow direction (upstream and downstream) of the fluid to be measured. They are arranged side by side. One ultrasonic wave propagation path 18C is located on the upstream side close to the front face 16a, and the other ultrasonic wave propagation path 20C is
It is located on the downstream side away from the

The transmitting ultrasonic sensors 30C and 32C are opposed to one ends of the ultrasonic propagation paths 18C and 20C, and the receiving ultrasonic sensor 34C is connected to the other ends of the ultrasonic transmitting paths 18C and 20C. , 36C face each other.

In the third embodiment, the ultrasonic sensors 30C and 34C provided at both ends of the ultrasonic propagation path 18C constitute a first flow meter, and the ultrasonic sensors provided at both ends of the ultrasonic propagation path 20C. 36C and 38C constitute the second flow meter.

The ultrasonic waves transmitted from the transmitting ultrasonic sensors 30C and 32C propagate through the fluid in the ultrasonic propagation paths 18C and 20C, and are received by the receiving ultrasonic sensors 34C and 36C. Also, the receiving ultrasonic sensors 34C, 36C
When receiving the ultrasonic waves, outputs the respective detection signals to the arithmetic unit 47C.

The operation unit 47C includes amplifier circuits 48 and 50,
It has waveform shaping circuits 52 and 54, a flow rate calculation circuit 62, an averaging circuit 68, a display circuit 64, and an output circuit 66. Then, the flow rate calculation circuit 62 calculates the flow rate of the fluid to be measured flowing through the flow channel 12 from the respective detection signals output from the receiving ultrasonic sensors 34 and 36 based on the frequency of the Karman vortex by parallel processing. The averaging circuit 68 calculates the average value of the two types of flow rate values obtained from the detection signals measured by the receiving ultrasonic sensors 34 and 36, and calculates the average value of the two flow rate values.
4. Output to the output circuit 66.

As described above, in the ultrasonic vortex flow meter 90,
Since the average value of the flow rate values of the types is calculated, it is possible to reduce the variation due to the measurement error of the receiving ultrasonic sensors 34 and 36 and stabilize the measurement accuracy.

In the ultrasonic vortex flow meter 90, even if one of the two flow meters fails, the flow rate can be measured by the other flow meter.

[0055]

As described above, according to the first aspect of the present invention, the plurality of first passages are provided so as to be located on the upstream side and the downstream side in the flow direction of the fluid to be measured. Since the total length of the passages can be made all the same size, the timing of the generation of the alternating flow inside the plurality of passages becomes the same, and the detection deviation of the Karman vortex due to the plurality of passages over time can be eliminated. Deterioration of instrumental differences due to differences in flow velocity distribution inside the passage can be prevented, and the ultrasonic wave modulation conditions in each ultrasonic sensor can be made the same to increase measurement accuracy.

According to the second aspect of the present invention, since the lengths of both the pair of second passages communicating with the first passage are the same, the passage of the fluid to be measured flowing into or out of the second passage is performed. The time becomes the same, and the detection delay of Karman vortex detected by the pair of ultrasonic sensors can be eliminated.

According to the third aspect of the present invention, a plurality of first
A pair of second passages communicating with one of the passages;
The pair of second passages communicating with the other first passages are provided on the same plane in the longitudinal direction of the vortex generator, so that the first passage through which the fluid to be measured flows in or out from the second passages. By making the distance in the passage the same and making the ultrasonic wave modulation conditions the same for a pair of ultrasonic sensors, the measurement accuracy can be increased.

According to the fourth aspect of the present invention, the plurality of first
Phase comparing means for comparing the phase difference of each detection signal output from the plurality of ultrasonic sensors for detecting the flow of the fluid to be measured flowing through the passage of the fluid, and the flow rate of the fluid to be measured from the phase comparison result by the phase comparing means And the flow rate calculating means for calculating the temperature of the fluid to be measured can cancel the disturbance received in the same phase by both ultrasonic sensors, such as temperature change and pulsation,
Measurement accuracy can be further improved. As a result, the phase modulation signal (vortex signal) obtained when the phases are compared changes sinusoidally, thereby reducing the superposition of noise, preventing the loss of the vortex detection pulse, and measuring at the time of low flow rate measurement. Sensitivity can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of an ultrasonic vortex flowmeter according to the present invention.

FIG. 2 is a longitudinal sectional view taken along the line BB in FIG.

FIG. 3 is a transverse sectional view taken along line CC in FIG.

FIG. 4 is a longitudinal sectional view of the vortex generator 16A of the first embodiment as viewed from the downstream side.

FIG. 5 is a longitudinal sectional view taken along line DD in FIG. 4;

FIG. 6 is a longitudinal sectional view taken along line EE in FIG. 4;

FIG. 7 is a longitudinal sectional view of the vortex generator 16B of the second embodiment viewed from the downstream side.

8 is a longitudinal sectional view taken along line FF in FIG. 7;

9 is a longitudinal sectional view taken along line GG in FIG.

FIG. 10 is a longitudinal sectional view of a vortex generator 16C of a third embodiment as viewed from the downstream side.

11 is a longitudinal sectional view taken along the line HH in FIG.

12 is a vertical sectional view taken along the line II in FIG.

FIG. 13 is a configuration diagram of an ultrasonic vortex flowmeter 90 according to a third embodiment.

FIG. 14 is a configuration diagram showing an example of a conventional ultrasonic vortex flowmeter.

FIG. 15 is a longitudinal sectional view taken along line AA in FIG.

[Explanation of symbols]

10, 70, 80, 90 Ultrasonic vortex flow meter 12 Flow path 14 Flow meter main body 16A to 16D Vortex generator 18A to 18D, 20A to 20D Passage 22A to 22D, 24A to 24D, 26A to 26D, 2
8A to 28D Fluid inlet / outlet ports 30A to 30D, 32A to 32D Transmitting ultrasonic sensors 34A to 34D, 36A to 36D Receiving ultrasonic sensors 38, 40 Holding members 38a, 38b, 40a, 40b Mounting holes 46 Oscillator 47 Operating section 48, 50 amplifier circuit 52, 54 waveform shaping circuit 56 phase comparison circuit 62 flow rate calculation circuit 68 averaging circuit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroshi Ohashi 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Inside Osaka Gas Co., Ltd. (72) Inventor Koichi Tashiro 1-6 Fujimi, Kawasaki-ku, Kawasaki-shi, Kawasaki No. 3 Tokiko Co., Ltd. (72) Inventor Hiroshi Yoshikura 1-6-3 Fujimi, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Tokiko Co., Ltd.

Claims (4)

[Claims] 1. A flowmeter body in which a flow path through which a fluid to be measured flows is formed; a vortex generator provided in the flow path so as to be orthogonal to a flow direction; and a vortex generator extending in a longitudinal direction of the vortex generator. A plurality of first passages, an ultrasonic sensor provided in each of the plurality of first passages, and detecting a flow of a fluid to be measured flowing in each of the first passages; and the plurality of first passages. A pair of second passages respectively provided to each of the first passages and the side wall of the vortex generator, and comprising: a pair of second passages, wherein the plurality of first passages are measured with each other. An ultrasonic vortex flowmeter provided so as to be located on an upstream side and a downstream side in a flow direction of a fluid. 2. The ultrasonic vortex flowmeter according to claim 1, wherein both lengths of the pair of second passages communicating with the first passages have the same length. 3. A pair of second passages communicating with one of the plurality of first passages and a pair of second passages communicating with the other first passage are formed in a longitudinal direction of the vortex generator. The ultrasonic vortex flowmeter according to claim 1, wherein the ultrasonic vortex flowmeter is provided on the same plane in the directions. 4. A phase comparing means for comparing a phase difference between respective detection signals output from a plurality of ultrasonic sensors for detecting a flow of a fluid to be measured flowing through the plurality of first passages, 4. The ultrasonic vortex flowmeter according to claim 1, further comprising: flow rate calculating means for calculating a flow rate of the fluid to be measured from the phase comparison result by the means.