JPH0532732Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic flowmeter, and particularly to a structure for attaching an ultrasonic transducer unit (hereinafter simply referred to as a unit) to a measuring tube.

[Prior Art] Ultrasonic flowmeters that use fluid as a propagation medium for ultrasonic waves and measure the flow rate and flow rate of the fluid based on the propagation time have been widely used.

As this type of ultrasonic flowmeter, the
There is one disclosed in Publication No. 77915. In this proposal, as shown in FIG. 4, a pair of vibrator housings 2 and 3 are integrally formed on a line diagonally crossing the fluid flow direction at opposing positions of the tube body 1. Units 4 and 5 are attached to these vibrator housings 2 and 3, respectively, via screws or the like. And one unit 4
Alternatively, an ultrasonic signal is emitted into the fluid from unit 5 or 4 and received by the other unit 5 or 4, and these transmissions and receptions are repeated alternately to determine the fluid flow velocity or It was configured to measure the flow rate.

[Problems to be solved by the invention] However, if the opposing units 4 and 5 are arranged on the same line as in the above proposal,
The curves showing the relationship between the flow velocity of the fluid and the amplitude of the ultrasonic waves are shown in Fig. 5 as solid lines and broken lines, respectively, when the ultrasonic waves are emitted in the direction from units 4 to 5 and when they are emitted in the opposite direction. Different as shown. That is, for example, the fluid moves inside the pipe body 1 in the direction of arrow A by +1.5
When the fluid flows at a flow rate of /sec, the amplitude of the ultrasound when it is emitted in the forward direction of the fluid flow direction A from unit 4 to 5 is approximately 1.6V after voltage conversion. Conversely, when ultrasonic waves are emitted, the voltage is approximately 3V. Similarly, when the fluid flow is in the direction of arrow B, the amplitude is 1.6V at a flow rate of -1.5/sec when the ultrasonic wave is in the forward direction of the fluid flow direction B, and 3V when it is in the opposite direction. Become. In this case, the limit to which the amplitude of the ultrasonic wave can be measured as a voltage is approximately 1V, so the measurable range is the fifth
There was a problem that the flow velocity range was between a and b as shown in the figure, and the measurement range became narrow.

An object of the present invention is to provide an ultrasonic flowmeter that can solve the above problems and widen the measurement range.

[Means for Solving the Problems] The ultrasonic flow meter according to the present invention is installed in a pipe through which a fluid flows so as to be inclined and face each other in the flow direction of the fluid, and transmits an ultrasonic signal. The center lines of the ultrasonic waves respectively emitted from a pair of ultrasonic transducer units that transmit and receive to measure the flow velocity or flow rate of the fluid flowing through the tube body are at positions spaced apart from each other on the center line of the tube body. The lines are arranged in such a way that they are parallel lines that intersect.

[Operation] According to the above configuration, the relationship between the flow velocity of the fluid and the amplitude of the ultrasonic wave is maintained regardless of whether the direction in which the ultrasonic wave propagates is in the forward direction or in the opposite direction to the flow direction of the fluid flowing through the tube. are almost the same, and even if the flow direction of the fluid changes, the relationship between the flow velocity and the amplitude of the ultrasonic wave hardly changes, so the measurement range can be widened.

[Example] Hereinafter, the present invention will be described in detail based on the illustrated example.

FIG. 1 is a sectional view showing an embodiment of an ultrasonic flow meter according to the present invention. In this figure, the same or equivalent parts as in the conventional example shown in FIG. 4 are denoted by the same reference numerals, and the explanation thereof will be omitted. The intersection point between the center line 4a of the unit 4 and the center line 1a of the tube body 1 is defined as m, and the center line 5a of the unit 5 and the center line 1 of the tube body 1 are defined as m.
If the intersection with a is n, then these intersections m,
n are located close to the B direction and A direction of the tube body 1, respectively, and the distance between these intersection points m and n is about 2 mm. These center lines 4a and 5a are parallel and intersect with the center line 1a of the tubular body 1 at an angle of about 30 degrees.

The operation of this embodiment configured as described above will be explained below. According to the experimental values, as shown in Fig. 2, when the distance between the intersections m and n is 0 mm, 1 mm, and 2 mm, the relationship between the flow rate and the value obtained by converting the amplitude of the ultrasonic wave into voltage is curve D, respectively. They will be shown as E and F. However, the curve shown by a solid line is the case where the ultrasonic wave is emitted in the forward direction of the flow direction of the fluid flowing inside the tube body 1, and the curve shown by the broken line is the case where the ultrasonic wave is emitted in the opposite direction. As shown in FIG. 2, if the intersection between the intersections m and n is 2 mm, the curve will be almost the same regardless of the direction in which the ultrasonic waves are emitted. Therefore, as shown in FIG. 3, when the flow rate of the fluid in the tube body 1 is, for example, ±1.5/sec, the amplitude of the ultrasonic wave is approximately 3 V in terms of voltage conversion. As a result, if the voltage that can be detected is 1V, the measurement range is 5th.
This is much wider than the conventional measurement range shown in the figure.
In the embodiment described above, the installation angle of the unit is
It is approximately 30 degrees with respect to the center line 1a of the unit 4, 5, and the center line 1a of the tube body 1.
We have explained the case where the measurement range is widest when the distance between the respective intersections m and n with the It is not limited to numbers.

In addition, if an infrared detector is installed between the units to measure the flow rate or flow rate of the fluid flowing through the pipe body 1 and at the same time the concentration of a specific component in the fluid, the distance between the units will be wide. It also has the effect of being easy.

[Effects of the invention] As described above, according to the invention, the center lines of the pair of inclined units on the tube body of the ultrasonic flowmeter are made into parallel lines with an appropriate interval.
The measurement range can be widened regardless of the direction of the ultrasonic waves emitted from the unit.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of an ultrasonic flowmeter according to the present invention, Figs. 2 and 3 are graphs showing the relationship between flow velocity and ultrasonic amplitude, and Fig. 4 is a graph showing a conventional ultrasonic flowmeter. FIG. 5 is a cross-sectional view showing the flow rate meter, and is a graph showing the relationship between the flow rate of the flow meter shown in FIG. 4 and the amplitude of ultrasonic waves. 1... tube body, 1a... center line of tube body, 4, 5...
...Ultrasonic transducer unit, 4a, 5a... Center line of ultrasonic transducer.

Claims (1)

[Scope of utility model registration request] A pair of tubes that are attached to a tube through which a fluid flows so as to face each other while being inclined in the flow direction of the fluid, and transmit and receive ultrasonic signals to measure the flow rate or flow rate of the fluid flowing through the tube. In an ultrasonic flowmeter equipped with an ultrasonic transducer unit, parallel lines where the center lines of the ultrasonic waves respectively emitted from the pair of ultrasonic transducers intersect at positions spaced apart from each other on the center line of the tube body. An ultrasonic flow rate meter characterized by: