JP2002357466A - Ultrasonic flow meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic flow meter capable of accurately measuring the flow rate of a fluid flowing through a thin flow tube. SOLUTION: Each of an inflow port 8 and an outflow port 9 is constituted of flow tubes having a circular cross section, and a flow tube 10 with a rectangular cross section having short sides 10a and 10b and long sides is connected between the inflow port 8a and the outflow port 9. The flow quantity of the fluid passing through the flow tube 10 has a flow rate higher than that of fluid passing through the inflow port 8 and the outflow port 9. A first sound matching body 11 is installed to the short side 10a of the rectangular flow tube 10, while a second sound matching body 13 is installed to the short side 10b opposed to the short side 10a in the flow tube 10. Ultrasonic oscillators 12 and 14 are installed to the first and second sound matching bodies 11 and 13 individually.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flowmeter capable of accurately measuring the flow rate of a fluid flowing through a thin flow pipe.

[0002]

2. Description of the Related Art As a conventional ultrasonic flow meter, as shown in FIGS. 6 and 7, a first side wall of a flow pipe 1 having a circular cross section is provided.
And the second acoustic matching member 4 is attached to the opposed portion of the circular flow pipe 1, and the first and second acoustic matching members 2 and 4 are respectively attached to the first and second acoustic matching members 2 and 4. Ultrasonic transducer 3,
5, the ultrasonic wave radiated from the first ultrasonic transducer 3 into the flow pipe 1 via the first acoustic matching body 2 is irradiated in the same direction as the flow of the fluid, and It is input to the ultrasonic vibrator 5 via the second acoustic matching member 4 mounted on the opposing wall, and is also irradiated from the second ultrasonic vibrator 5 through the acoustic matching member 4 into the distribution pipe 1. The ultrasonic wave is irradiated in the direction opposite to the flow of the fluid, is input to the first ultrasonic vibrator 3 via the first acoustic matching body 2, is irradiated from the first ultrasonic vibrator 3, and The flow rate of the fluid is measured from the difference between the time to reach the ultrasonic vibrator 5 and the time from the irradiation from the second ultrasonic vibrator 5 to the first ultrasonic vibrator 3.

Alternatively, as shown in FIG. 8, first and third acoustic matching bodies 2 and 6 are mounted in parallel on a flow pipe 1 with a space therebetween, and the first and third acoustic matching bodies 2 and 6 are provided. The first and third ultrasonic vibrators 3 and 7 are attached to the first and second ultrasonic vibrators, respectively, and the ultrasonic waves emitted from the first ultrasonic vibrator 3 are irradiated into the fluid in the flow pipe 1 via the acoustic matching body 2. , Reflected on the opposite side of the distribution pipe 1,
Irradiation is performed in the direction of the flow of the fluid, and input to the third ultrasonic vibrator 7 via the third acoustic matching member 6. Similarly, irradiation is performed from the third ultrasonic vibrator 7. The ultrasonic wave is applied to the fluid in the flow pipe 1 through the acoustic matching member 6,
The light is reflected on the opposite side of the flow pipe 1 and irradiated in the direction opposite to the flow of the fluid, and is input to the first ultrasonic vibrator 3 via the first acoustic matching body 2, and the first ultrasonic vibrator The flow rate of the fluid is determined from the difference between the time required to irradiate from the third ultrasonic transducer 7 and reach the third ultrasonic vibrator 7 and the time required to irradiate the third ultrasonic vibrator 7 and reach the first ultrasonic vibrator 3. Is configured to be measured.

[0004]

However, in such an ultrasonic flow meter, when the diameter of the flow pipe 1 is large,
Since the ultrasonic vibrators 3 and 5 mounted facing the flow pipe 1 and the ultrasonic vibrators 3 and 7 provided in parallel with the flow pipe 1 have a sufficient distance, the flow rate of the liquid flowing through the flow pipe 1 can be accurately determined. However, when the diameter of the distribution pipe 1 is small,
The first and second ultrasonic vibrators 3 and 5 mounted facing the flow pipe 1 or the ultrasonic vibrator 3 mounted parallel to the flow pipe 1
7 cannot be measured sufficiently, so that the flow rate of the liquid flowing through the flow pipe 1 cannot be accurately measured.

[0005]

SUMMARY OF THE INVENTION The present invention comprises an inlet,
A flow pipe having a rectangular cross-section, which is communicated with the inlet, and provided to narrow the passage with respect to the flow inlet, an outlet provided in the flow pipe, and one short side of the flow pipe were mounted. First
And a first ultrasonic vibrator mounted on the first acoustic matching body, and a second ultrasonic vibrator mounted on the opposite short side of the flow pipe at an interval from the first acoustic matching body. An acoustic matching body and a second ultrasonic vibrator mounted on the second acoustic matching body, wherein the ultrasonic wave generated from the first ultrasonic vibrator is passed through the first acoustic matching body via the first acoustic matching body. Irradiating into the fluid of the flow pipe, passing through the opposing wall of the flow pipe, receiving through the second acoustic matching body by the second ultrasonic transducer,
Further, the second ultrasonic oscillator irradiates the first ultrasonic oscillator with ultrasonic waves, and irradiates the ultrasonic waves in the forward and reverse directions with respect to the flow of the fluid flowing through the flow pipe to reduce the flow rate. The first and second acoustic matching bodies are mounted on the same short side of the flow pipe at an interval, and the first and second ultrasonic transducers are mounted on the first and second acoustic transducers. Attached to each acoustic matching body,
Ultrasonic waves emitted from the first ultrasonic vibrator are radiated from the first acoustic matching body into the flow pipe, reflected at the other short side of the flow pipe, and mounted on the second acoustic matching body. 2 may be input to the ultrasonic vibrator, and the flow pipe is provided with two inclined portions that are respectively inclined from one short side of the rectangle to the inflow port and the outflow port, Through the first and second acoustic matching bodies on the two inclined portions, respectively,
The first and second ultrasonic vibrators may be mounted facing each other, and the flow pipe may be formed by crushing a tube having a circular cross section into an elliptical shape.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a first ultrasonic vibrator is mounted on one short side of a flow pipe having a rectangular cross section via a first acoustic matching body, and a second ultrasonic vibrator is mounted on the opposite short side. Or the first and second acoustic matching bodies are mounted at intervals on one short side of a flow pipe having a rectangular cross section. An ultrasonic transducer is attached to each acoustic matching body, or an inclined portion facing a short side of a flow pipe having a rectangular cross section is provided, and an ultrasonic transducer is provided in each of the inclined portions, so that an inflow port and an inflow port are provided. Even if the outlet is narrow, the cross section is made into a structure in which a rectangular or elliptical shape is crushed, so that the flow path is made thinner and rectangular, so that the measurement path becomes longer and the flow velocity becomes faster,
Since the difference between the time when the ultrasonic wave is applied to the flow of the fluid and the time when the ultrasonic wave is opposed to the flow is increased, the flow rate of the liquid flowing through the flow pipe is easily measured, and the measurement can be performed accurately.

[0007]

FIG. 1 is a side view of an ultrasonic flowmeter according to an embodiment of the present invention, and FIG. 2 is a sectional view of the ultrasonic flowmeter of FIG.
And the outlet 9 are each formed by a thin flow pipe having a circular cross section, and the cross section is a short piece 10 a between the inlet 8 and the outlet 9.
A rectangular flow pipe 10 having 10b and long sides 10c and 10d is connected, and the flow rate passing through the flow pipe 10 is an inlet 8. The first acoustic matching member 11 is attached to the short side 10a of the rectangular flow pipe 10 and has a flow velocity greater than the flow velocity of the fluid passing through the outlet 9; A matching body 13 is mounted, and ultrasonic vibrators 12 and 14 are mounted on the first and second acoustic matching bodies 11 and 13, respectively.

In the ultrasonic flowmeter of this embodiment having the above-described configuration, first, when an ultrasonic wave is emitted from the first ultrasonic vibrator 12, the emitted ultrasonic wave is transmitted to the first acoustic matching body 11.
Is irradiated into the flow pipe 10 from the short side 10a of the flow pipe 10 through the flow path, the ultrasonic wave is irradiated in the flow direction of the fluid, reaches the opposite short side 10b, and the second side attached to the opposite short side
The ultrasonic waves input from the acoustic matching body 13 to the second ultrasonic vibrator 14 and emitted from the second ultrasonic vibrator 14 are opposed to the flow pipe 10 through the second acoustic matching body 13. Irradiated into the fluid from the short side 10b thus formed, and input to the ultrasonic vibrator 12 from the first acoustic matching body 11 mounted on the short side 10a against the flow of the fluid, whereby the first ultrasonic vibration From the transducer 12 to the second ultrasonic transducer 14 and from the second ultrasonic transducer 14 to the first ultrasonic transducer 12
The flow rate of the fluid flowing through the flow pipe 10 can be measured from the difference in the time to reach the flow rate, and the time difference can be made large. Therefore, even if the flow rate is small, the flow rate can be accurately measured.

FIG. 3 is a side sectional view of an ultrasonic flowmeter according to another embodiment of the present invention, wherein 8 is an inlet, 9 is an outlet, 10 is a flow pipe, and 11 and 13 are first and second acoustics. Matching body, 12, 14
Are the first and second ultrasonic transducers, and their configurations are the same as those in the above embodiment. Therefore, description thereof is omitted, but in this embodiment, the first and second ultrasonic transducers 1,
The second acoustic matching bodies 11 and 13 are attached,
First and second ultrasonic vibrators 12 and 14 are mounted on the second acoustic matching bodies 11 and 13.

[0010] In the ultrasonic flowmeter of the present embodiment configured as described above, the ultrasonic waves emitted from the first ultrasonic vibrator 12 are passed through the first acoustic matching member 11 to the short side 10 of the flow pipe 10.
a in the direction of flow of the fluid, and is reflected by the opposite short side 10b of the flow pipe 10 to be reflected by the short side 10a of the flow pipe 10.
Is input to the second ultrasonic vibrator 14 through the second acoustic matching body 13, and the ultrasonic wave emitted from the second ultrasonic vibrator 14 is transmitted through the second acoustic matching body 13. Irradiated from the opposite short side 10b of the flow pipe 10 against the flow of fluid, and is input from the short side 10a of the flow pipe 10 to the first ultrasonic transducer 12 via the first acoustic matching body 11. As a result, the time required to reach the second ultrasonic transducer 14 from the first ultrasonic transducer 12 and the first ultrasonic transducer 14
From the difference in time to reach the ultrasonic transducer 12
Since the flow rate of the fluid flowing through the fluid can be measured, and the time difference between them can be made large, the flow rate can be measured accurately even if the flow rate is small.

FIG. 4 is a side sectional view of an ultrasonic flow meter according to another embodiment of the present invention, and FIG. 5 is a sectional view of the ultrasonic flow meter of FIG.
The flow pipe 10 has a rectangular cross section, and the other short side 10b of the flow pipe 10 coincides with the side of the inflow port 8 and the outflow port 9, and extends from the inflow port 8 to the short side 10a of the flow pipe 10. Inclined portion 10e such that the width of the short side 10a is reduced.
Is formed, and from the outlet 9 toward the short side 10a,
The inclined portion 10f is formed so that the width of the short side 10a is reduced, and the long sides 10c and 10d of the rectangular shape of the flow pipe 10 are configured to be longer.
The ultrasonic transducers 12 and 14 are respectively mounted along the inclination.

In the thus constructed ultrasonic flow meter of this embodiment, the amount of liquid flowing from the inlet 8 and the outlet 9
Although the amount of liquid flowing out of the first and second ultrasonic transducers 12 and 14 is the same, the width of the flow pipe 10 is increased.
Can be lengthened, and the flow rate of the liquid can be measured accurately.

In the above embodiment, the cross section of the flow pipe 10 is rectangular, but the cross section becomes substantially rectangular by crushing the synthetic resin or metal pipe flat.
It can be used in the same manner as in the above embodiment.

[0014]

As described above, in the ultrasonic flowmeter of the present invention, the first and second ultrasonic vibrators are mounted on the short sides of the rectangle by making the cross section of the flow pipe rectangular. Thereby, the transmission path of the ultrasonic wave between the first and second ultrasonic transducers for measuring the flow rate can be lengthened, and an inclined portion is provided on each of the short sides of the flow pipe from the inlet and the outlet, By attaching the first and second ultrasonic vibrators to these inclined portions, respectively, it is possible to lengthen the transmission path of the ultrasonic wave between the first and second ultrasonic vibrators. Can be measured accurately, and even if the outlet and the diameter of the outlet are small, the transmission path of the ultrasonic wave can be lengthened at the same flow rate, so that the flow rate can be measured accurately, and , The circular cross section of the distribution pipe can be crushed to form an oval , There is an advantage that may be used pipes synthetic resin.

[Brief description of the drawings]

FIG. 1 is a side view of an ultrasonic flowmeter according to an embodiment of the present invention.

FIG. 2 is a sectional view of the ultrasonic flow meter of FIG.

FIG. 3 is a side view of an ultrasonic flowmeter according to another embodiment of the present invention.

FIG. 4 is a side view of an ultrasonic flowmeter according to another embodiment of the present invention.

FIG. 5 is a sectional view of the ultrasonic flow meter of FIG. 4;

FIG. 6 is a side view of a conventional ultrasonic flowmeter.

FIG. 7 is a sectional view of the ultrasonic flow meter of FIG. 5;

FIG. 8 is a side view of another conventional ultrasonic flowmeter.

[Explanation of symbols]

 Reference Signs List 8 Inlet 9 Outlet 10 Flow pipe 10a, 10b Short side 10c, 10d Long side 10e, 10f Inclined part 11, 13 First, second acoustic matching body 12, 14, First, second ultrasonic transducer

Claims (4)

[Claims] 1. An inflow port, a flow pipe having a rectangular cross section which is communicated with the inflow port and is provided to narrow the passage with respect to the inflow port, an outflow port provided in the flow pipe, and A first acoustic matching member attached to one short side of the tube, a first ultrasonic vibrator attached to the first acoustic matching member, and the circulation tube spaced apart from the first acoustic matching member A second acoustic matching body mounted on the opposite short side of the first acoustic matching body and a second ultrasonic vibrator mounted on the second acoustic matching body. The ultrasonic wave generated from the first ultrasonic vibrator is Irradiates the fluid in the flow pipe through the first acoustic matching body, passes through the opposed wall of the flow pipe, and is received by the second ultrasonic transducer via the second acoustic matching body. In addition, the second ultrasonic vibrator irradiates the first ultrasonic vibrator with ultrasonic waves to control the flow of the fluid flowing through the flow pipe. An ultrasonic flowmeter for irradiating ultrasonic waves in forward and reverse directions to measure the flow rate. 2. The first and second acoustic matching bodies are mounted on the same short side of the flow pipe at an interval, and the first and second ultrasonic vibrators are mounted on the first and second acoustic transducers. The ultrasonic waves emitted from the first ultrasonic vibrator attached to the matching bodies respectively are the first ultrasonic vibrators.
The second acoustic matching member attached to the second acoustic matching member is radiated from the acoustic matching member to the inside of the circulation tube, reflected at another short side of the circulation tube, and attached to the second acoustic matching member.
The ultrasonic flowmeter according to claim 1, wherein the ultrasonic flow is input to the ultrasonic vibrator. 3. The flow pipe is provided with two inclined portions which are respectively inclined from one short side of the rectangle with respect to the inlet and the outlet, and the first and second inclined portions are respectively provided on the two inclined portions. The first and second ultrasonic vibrators are mounted to face each other via two acoustic matching bodies.
An ultrasonic flowmeter as described. 4. The flow pipe according to claim 1, wherein the flow pipe is formed by crushing a circular tube into an elliptical shape.
4. An ultrasonic flowmeter according to any one of claims 1 to 3.