JP2564396B2 - Ultrasonic vortex flowmeter - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic vortex flowmeter, and in particular, it is suitable for measurement of ultrapure water, clean fluids such as chemical fluids and foods, and corrosive fluids. Acoustic vortex flowmeter.

BACKGROUND ART Flowmeters for measuring special fluids such as ultrapure water, chemical fluids, clean fluids such as food, corrosive fluids, etc.
In the case of measuring a clean fluid, generation of dust from the flowmeter itself is not permitted, and in the case of measuring a corrosive fluid, elution of the members constituting the flowmeter from the liquid contact portion is not permitted. Therefore, the flowmeters used for measuring the flow rates of these fluids are limited, and conventionally, vortex flowmeters using electromagnetic flowmeters or piezoelectric elements have been used.

The problem to be solved by the invention However, the electromagnetic flowmeter has a problem in that, due to its measuring principle, only a fluid having conductivity can be measured, and the fluid to be measured is limited. Further, since the induced electromotive force is very small, a high performance amplifier is required, which is expensive, and there is a problem that handling and maintenance are troublesome.

On the other hand, dust is contained in the fluid flowing in the pipeline,
When this dust adheres to the inner wall of the pipe in the vicinity of the position where the detection device (electromagnetic pickup or piezoelectric element) is installed, the conventional vortex flowmeter has a function of removing the dust adhering to the inner wall of the pipe. Therefore, there is a problem that the measurement accuracy is deteriorated due to the adhesion of dust.

Further, in the flow meter using the piezoelectric element, the change in stress generated in the pressure receiving body due to the Karman vortex is detected by the piezoelectric element, so that the flow velocity distribution in the pipe affects the pressure receiving body and the measurement accuracy deteriorates. There is a problem that there is a possibility that the piezoelectric element may be disposed further inside the pressure receiving body disposed in the pipe, which complicates the structure of the vortex flowmeter.

The present invention has been made in view of the above points, and an object thereof is to provide an ultrasonic vortex flowmeter that can perform highly accurate flow rate measurement regardless of the type of fluid to be measured and measurement conditions, and that is inexpensive. To do.

Means for Solving the Problems In order to solve the above problems, in the present invention, in order to detect the generation frequency of a Karman vortex generated on the downstream side of a vortex generator disposed in a conduit through which a fluid flows, At least one set of an ultrasonic transmitter that emits ultrasonic waves in the passage and an ultrasonic receiver that receives the ultrasonic waves emitted from the ultrasonic transmitter is provided, and the inner surface of the conduit, the vortex generator, and the ultrasonic generator It is characterized in that each of the liquid contact parts of the sound wave transmitter and the ultrasonic wave receiver is coated with a chemically stable substance.

Action In the ultrasonic vortex flowmeter configured as described above, since the ultrasonic transmitter and the ultrasonic receiver are used as the device for detecting the generation frequency of the Karman vortex, the ultrasonic transmitter is the fluid to be measured. When the directed ultrasonic wave is emitted, the ultrasonic wave is transmitted through the chemically stable substance coated on the liquid contact portion into the duct. Therefore, even if dust is contained in the fluid and this dust adheres to the chemically stable substance coated in the conduit,
Since the chemically stable substance is ultrasonically vibrated by the ultrasonic transmitter, the attached dust can be removed. For this reason,
Ultrasonic waves can be radiated toward the fluid flowing in the conduit without being disturbed by dust, and the measurement accuracy can be improved.

Also, since the wetted part is covered with a chemically stable substance, when a clean fluid is used as the fluid to be measured, it is possible to prevent dust from entering the fluid from the components of the vortex flowmeter, and When a corrosive fluid is used as the fluid,
It is possible to prevent the liquid contact part of the vortex flowmeter from dissolving.

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a vertical sectional view of an ultrasonic vortex flowmeter 1 (hereinafter simply referred to as an overflow meter 1) which is an embodiment of the present invention, and FIG.
The figure shows the A direction arrow view in the figure.

In the figure, 2 is a pipeline through which the fluid to be measured flows.
A vortex generator 3 for generating a Karman vortex in the fluid to be measured is arranged in the. Further, the vortex flowmeter 1 is configured to detect the generation frequency of the Karman vortex by using ultrasonic waves (this will be described later), and therefore, the ultrasonic wave is provided in the downstream pipe line of the vortex generator 3. Transmitters 4a, 4b and ultrasonic receiver 5a,
5b is provided. At this time, each ultrasonic transmitter / receiver 4a, 4
b, 5a, 5b are ultrasonic propagation paths from the ultrasonic transmitter 4a to the ultrasonic receiver 5a, and the ultrasonic transmission signal 4b from the ultrasonic receiver
The ultrasonic wave propagation paths up to 5b are arranged so as to intersect each other, and the ultrasonic wave propagation path is configured to simultaneously cross one vortex generated by the vortex generator 3.

The ultrasonic transmitters 4a and 4b are driven by the connected ultrasonic oscillator 6 and emit ultrasonic waves toward the fluid to be measured. The ultrasonic receivers 5a and 5b receive the ultrasonic waves emitted from the ultrasonic transmitters 4a and 4b. This ultrasonic receiver 5a, 5b has a phase comparator
7, the waveform shaping circuit 8 is connected.

The vortex flowmeter 1 according to the present invention uses the ultrasonic transmitters 4a and 4b and the ultrasonic receivers 5a and 5b as the detection device for detecting the Karman vortex as described above, and the liquid contact portion in contact with the fluid to be measured is made of fluorine. It is characterized by being coated with a resin 9 (shown as satin in the figure). Therefore, in the vortex flowmeter 1, the pipe line 2, the vortex generator 3, and the transceivers 4a, 4b, 5a, 5b constituting the vortex flowmeter 1 do not come into direct contact with the fluid to be measured. Further, as is well known, the fluororesin 9 is a chemically stable substance. Therefore,
Even if the vortex flowmeter 1 is used for measurement of a highly corrosive fluid to be measured, the liquid contact portion will not be dissolved or corroded. Further, the vortex flowmeter 1 has a liquid contact portion coated with a fluororesin 9,
Moreover, since there are no moving parts, dust etc. does not occur,
Therefore, it can be applied to the flow rate measurement of clean fluid. Further, by coating the liquid contact portion with a resin, the coefficient of friction of the pipe becomes small, and the flow velocity distribution in the pipe can be averaged, and the measurement accuracy can be improved. Further, since the vortex flowmeter 1 is configured to measure the flow rate from the generation frequency of the Karman vortex, it is not limited to the type of the fluid to be measured, and for example, the flow rate of the non-conductive fluid can be measured. It is inexpensive because it has a simple structure and does not require the use of high-performance electronic devices.

In the present embodiment, the configuration in which the liquid contact portion is coated with the fluororesin 9 has been described, but the substance to be coated is not limited to the fluororesin, and the coating may be performed by ceramic spraying, for example. That is, it is clear from the above description that the substance to be coated can exhibit the effect of the present invention as long as it is a substance stable to the fluid to be measured. Further, the coating means is not limited, and may be appropriately selected depending on the type of substance to be coated such as coating treatment and plating. Next, the operation of the vortex flowmeter 1 having the above configuration will be described.

The ultrasonic oscillator 6 drives the ultrasonic transmitters 4a and 4b to radiate ultrasonic waves through the fluororesin 9 in the fluid to be measured. On the other hand, a Karman vortex is generated in the fluid to be measured flowing in the conduit 2 by the vortex generator 3 at a frequency proportional to the flow rate. The ultrasonic waves emitted from the ultrasonic transmitters 4a and 4b are received by the ultrasonic receivers 5a and 5b.
Undergoes phase modulation by the Karman vortex on the propagation path up to.

At this time, the ultrasonic waves emitted from the ultrasonic transmitters 4a and 4b pass through the fluororesin 9 and are emitted toward the fluid to be measured. For this reason, even if the fluid to be measured contains dust and the dust adheres to the fluororesin 9 covered in the conduit 2, the fluororesin 9 is ultrasonically vibrated by the ultrasonic transmitters 4a and 4b. Therefore, the attached dust can be removed. Therefore, since the part where the ultrasonic waves are radiated from the ultrasonic transmitters 4a and 4b always maintains the state in which the dust is removed, the ultrasonic wave can be directed to the fluid flowing in the pipe line 2 without being disturbed by the dust. It is possible to radiate light to the surface, and the measurement accuracy can be improved.

Furthermore, as described above, each of the ultrasonic transmitters / receivers 4a, 4b, 5
Since a and 5b have been selected to be installed at specific positions,
The ultrasonic transmitters 4a, 4b and the ultrasonic receivers 5a, 5b do not need to be installed so that the ultrasonic waves are obliquely incident on the pipeline wall, and the installation design is simple. The sound wave transmitting / receiving devices 4a, 4b, 5a, 5b will not be uneven. This can minimize the effect on the flow of fluid, especially at the interface between the pipeline and the fluid.
Stable measurement is possible. In addition, since the ultrasonic wave propagation paths that cross the vortex do not separate from each other in the vertical direction and can pass through the central portion of the flow path cross section, the strongest and stable vortex generated near the center of the flow path can be detected. .

The characteristics and actions based on the arrangement positions of the ultrasonic transmitters / receivers 4a, 4b, 5a, 5b are the same as those of Japanese Patent Application No. 63-123060 “Vortex Flowmeter” previously proposed by the applicant. It is detailed.

The ultrasonic receivers 5a and 5b supply the ultrasonic waves transmitted through the fluororesin 9 to the phase comparator 7 which has converted them into electric signals. The phase comparator 7 compares the phases of the signals coming from the ultrasonic receivers 5a and 5b to detect the phase modulation signal by the Karman vortex, and further shapes the detection signal by the waveform shaping circuit 8 to output the output terminal 10 More vortex signal is output.

As described above, in the vortex flowmeter 1, the ultrasonic transmitters / receivers 4a, 4b, 5 which can detect the Karman vortex without contacting the fluid to be measured.
Since a and 5b are used, the liquid contact part in the conduit 2 can be entirely covered with the fluororesin 9, and the occurrence of dissolution and corrosion in the sensor part can be reliably prevented.

As described above, according to the present invention, since the ultrasonic transmitter and the ultrasonic receiver are used as the device for detecting the generation frequency of the Karman vortex, the ultrasonic transmitter is directed toward the fluid to be measured. When radiating ultrasonic waves, the ultrasonic waves pass through the chemically stable substance coated on the liquid contact part and are transmitted to the inside of the pipeline, so that dust is contained in the fluid and this dust is coated inside the pipeline. Even if the chemically stable substance adheres to the adhered chemically stable substance, the chemically stable substance is ultrasonically vibrated by the ultrasonic transmitter, so that the adhered dust can be removed. Therefore, it becomes possible to radiate ultrasonic waves toward the fluid flowing in the conduit without being disturbed by dust, and the measurement accuracy of the vortex flowmeter can be improved.

Also, since the wetted part is coated with a chemically stable substance, when a clean fluid is used as the fluid to be measured, it is possible to prevent dust from entering the fluid from the components of the overflow meter, and to measure the fluid to be measured. When a corrosive fluid is used as the fluid,
It is possible to prevent the liquid contact part of the overflow meter from being dissolved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an overflow meter which is an embodiment of the present invention,
FIG. 2 is a view on arrow A in FIG. 1 ... Vortex flowmeter, 2 ... Pipeline, 9 ... Fluorine resin.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michio Nitta 2-47-27 Wada, Suginami-ku, Tokyo (56) References JP-A-51-85753 (JP, A) SAIKAI 59-12012 (JP, U) Actually opened 60-139224 (JP, U) Actually opened 59-161033 (JP, U)

Claims (1)

(57) [Claims] 1. An ultrasonic transmitter for radiating an ultrasonic wave into the conduit for detecting the generation frequency of a Karman vortex generated on the downstream side of a vortex generator disposed in a conduit through which a fluid flows, At least one ultrasonic wave receiver for receiving the ultrasonic waves emitted from the ultrasonic wave transmitter is provided, and the inner surface of the conduit, the vortex generator, the ultrasonic wave transmitter, and the liquid contact parts of the ultrasonic wave receiver are provided. An ultrasonic vortex flowmeter, characterized in that it is formed by coating a chemically stable substance.