JPH07218303A - Current meter - Google Patents

Abstract

PURPOSE:To provide a current meter utilizing ultrasonic echo capable of being arranged in any direction without performing calibration. CONSTITUTION:An ultrasonic oscillator 14 is attached to one end of a tubular part 10 so as to transmit ultrasonic waves toward the float 12 inserted in the tubular part 10 with tapered its caliber and receiving the echos of the ultrasonic waves to detect the position of the float 12 by a predetermined signal processing circuit. The spring 16 exerting force on the float 12 in the direction reverse to the flow direction of a fluid 30 is provided in the tubular part 10. The effective wt. of the float 12 in the fluid 30 is set to zero or to a properly small value so that the float 12 stops at a position where the force in the flow direction of the fluid applied to the float by the flow of the fluid and the force of the spring 16 are almost balanced when the fluid flows through the tubular part 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a velocity meter utilizing ultrasonic echo.

[0002]

2. Description of the Related Art An example of a velocity meter utilizing ultrasonic echo is disclosed in Japanese Patent Application Laid-Open No. 1-313720. FIG. 2 is a schematic partial cross-sectional view illustrating this velocity meter. The fluid 58 passes through the tubular portion 54, and the diameter 56 thereof changes in a tapered shape. The float 6 is provided inside the tubular portion 54.
0, which rises and falls according to the flow velocity of the fluid 58. Float 60
The upper surface 60a of the above is flat, the ultrasonic transducer 24 is provided at the upper end of the tubular portion 54, and the ultrasonic wave is reflected by the upper surface 60a of the float 60. Since the float 60 moves up and down according to the flow velocity, this propagation is measured by measuring the propagation time from the ultrasonic transducer 24 transmitting the ultrasonic wave toward the float 60 until receiving the ultrasonic echo. The relationship between time and the flow velocity of the fluid 58 can be clarified. Therefore, the flow velocity of the fluid 58 can be known by measuring this propagation time using an appropriate signal processing circuit.

[0003]

In the above velocity meter, the flow of the fluid 58 is restricted by the float 60, and a force is applied to the float 60 in the flow direction of the fluid 58 by the differential pressure generated before and after the flow. This force becomes smaller as the float 60 moves in the direction in which the diameter of the tubular portion 54 expands. Therefore, when the tubular portion 54 of the anemometer is vertically arranged, the float 6 is placed at a position where this force and the effective weight of the float in the fluid are balanced.
0 is stationary. The effective weight of the float 60 in the fluid 58 is the weight of the float obtained by subtracting the amount of buoyancy acting on the float from the weight of the float. When the flow of the fluid 58 flowing through the anemometer becomes faster and the momentum increases, the vertical gravity acting on the float 60 is always constant, but the differential pressure before and after the float 60 becomes large. The float 60 rises to a position where it is in equilibrium with the effective weight of the float, and the flow velocity can be known from the position of the float 60.

However, when the tubular portion of the anemometer is attached so as to be inclined with respect to the vertical direction, the components of gravity acting on the float along the direction of the fluid flow change depending on the degree of inclination, so these forces are balanced. The position of the float 60 changes, and the propagation time until the ultrasonic transducer 24 receives the echo of the ultrasonic wave transmitted toward the float 60 also changes. Therefore, when the velocimeter is attached with the tubular portion 54 inclined, the relationship between the actual flow velocity and the ultrasonic wave propagation time must be obtained again. That is, calibration is required. Further, when the tubular portion 54 of the anemometer is arranged horizontally, the gravity component along the flow direction of the fluid is 0, so that the float is pressed toward the outlet of the tubular portion 54 by the pressure of the fluid, and It cannot be measured. Therefore, it is an object of the present invention to provide a velocity meter using an ultrasonic echo that can accurately measure the velocity without calibration in any direction.

[0005]

In order to achieve the above object, according to the present invention, an urging means for exerting a force in a direction opposite to the flow direction of a fluid flowing through a tubular portion of a velocity meter is provided in the velocity meter. There is. By doing so, the force of the fluid flow and the force of the biasing means can be made substantially equal, and the influence of gravity acting on the float can be reduced. That is, a tubular portion having a tapered diameter, a float inserted in the tubular portion, and an ultrasonic wave emitted toward the float and the tubular portion so that an echo of the ultrasonic wave can be received. In an anemometer having an ultrasonic transducer arranged at one end of
There is provided a velocity meter characterized by comprising biasing means for exerting a force on the float in a direction opposite to a flow direction of a fluid flowing through the tubular portion.

Further, in another aspect of the present invention, in addition to providing the above-mentioned biasing means, when the fluid flows through the tubular portion, the force and the biasing force applied to the float by the flow of the fluid in the direction of the flow of the fluid. The effective weight of the float in the fluid is set to zero or set small so that the float stands still at a position where the force of the means is almost balanced. Therefore, the float can be stopped at a position where the force exerted on the float by the biasing means and the force exerted on the float in the flow direction of the fluid by the flow of the fluid are substantially balanced without depending on the gravity acting on the float. That is, when the fluid flows through the tubular portion, the float floats so that the float rests at a position where the force in the flow direction of the fluid applied to the float by the flow of the fluid and the force of the biasing means are approximately balanced. The flowmeter according to claim 1, wherein the effective weight of the fluid in the fluid is 0 or is set to be appropriately small.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic partial cross-sectional view illustrating an embodiment of the velocity meter of the present invention. An inlet 18 and an outlet 20 for the fluid 30 are provided near both ends of the tubular portion 10 of the anemometer. The diameter of the tubular portion 10 changes in a taper shape,
The diameter increases in the direction from the inlet 18 to the outlet 20. Hereinafter, the end portion of the tubular portion 10 on the larger diameter side is referred to as an upper end portion, and the smaller diameter side is referred to as a lower end portion. A shaft 22 is provided inside the tubular portion 10 along the center line of the tapered portion, and both ends of the shaft 22 are fixed to both ends of the tubular portion 10. The float 12 is shell-shaped in shape and is pierced by the shaft 22 and is movable along the shaft 22. When the surface of the float 12 that faces the direction in which the fluid 30 flows is called the upper surface 13, this upper surface 13 is flat, and the ultrasonic wave transmitted from the ultrasonic vibrator 14 to be described later is transmitted by the ultrasonic vibrator 1.
It is possible to reflect toward 4.

One end of a spring 16 is attached to the upper surface of the float 12, and the other end of the spring 16 is attached to the upper end of the tubular portion 10. The spring 16 is a compression spring and exerts a force on the float 12 in the direction opposite to the direction of the flow of the fluid when the float 12 is displaced in the direction of the flow of the fluid by the flow of the fluid.
The spring 16 and the shaft 22 constitute a biasing means for exerting a force on the float 12 in a direction opposite to the flow direction of the fluid 30. At the upper end of the tubular portion 10, a hole is provided in the vicinity of the position where the end of the shaft 22 is attached, and the ultrasonic transducer 14 is adhered to this hole with an adhesive without a gap. Ultrasonic transducer 1
4 is connected to a signal processing circuit (not shown), and the ultrasonic transducer 14 transmits ultrasonic waves in response to a signal from the signal processing circuit,
When the ultrasonic echo is received, the signal is output to the signal processing circuit.

Next, the operation of this anemometer will be described.
First, a case will be described in which the flow velocity meter is arranged so that the tubular portion 10 of the flow velocity meter is parallel to the vertical direction and the fluid is caused to flow at the flow velocity v. A buoyant force and a force due to the fluid flow act on the float 12 in the flow direction of the fluid 30, and at the same time, gravity and elastic force of the spring 16 act in the opposite direction to the flow direction of the fluid.
The weight of the float 12 is made substantially equal to the weight of the fluid 30 corresponding to the volume occupied by the float by adjusting the material and volume. For this reason, the gravitational force acting on the float and the buoyancy are canceled out, and the effective weight of the float 12 is almost equal to zero.
Therefore, the force acting on the float 12 can be considered to be substantially the force due to the flow of the fluid 30 and the elastic force due to the spring 16, and the two forces are balanced to make the float 12 stand still. Further, in order to make the effective weight of the float almost zero, the inside of the float may be hollow.

When the flow velocity is increased to V (> v) from this state of flow velocity v, the force exerted on the float 12 by the flow of the fluid 30 increases, and the float 12 is raised against the elastic force of the spring 16. However, as the float 12 rises in the direction in which the diameter of the tubular portion 10 increases, the gap between the float 12 and the wall surface of the tapered portion widens, so this force weakens, while the spring 16 tries to return to its natural length and its elasticity is reduced. Strengthen. Therefore, after the float 12 has risen to the upper end side of the tubular portion 10 to some extent, these two forces balance again and the float 12
Is stationary.

On the contrary, if the flow velocity is reduced to U (<v) from the state of the flow velocity v, the force exerted on the float 12 by the flow of the fluid 30 is reduced, and the float 12 is pushed down by the elastic force of the spring 16. However, as the float 12 descends in the direction in which the diameter of the tubular portion 10 decreases, the gap between the float 12 and the wall surface of the tapered portion becomes narrower, so this force becomes stronger, while the elastic force of the spring 16 becomes weaker. Therefore, after the float 12 descends to the lower end side of the tubular portion 10 to some extent, these two forces balance again and the float 12 stands still. in this way,
The position of the float is determined according to the flow velocity.

On the other hand, ultrasonic waves are transmitted from the ultrasonic vibrator 14 according to the signal from the signal processing circuit, and the ultrasonic waves are reflected by the upper surface of the floating body 12 which is stationary. Ultrasonic transducer 14
Receives the echo of the ultrasonic wave due to this reflection and outputs a signal to the signal processing circuit. The signal processing circuit measures the propagation time of the ultrasonic wave from the time when the ultrasonic wave is transmitted until the ultrasonic wave echo is received by the ultrasonic vibrator 14. The propagation time of this ultrasonic wave is determined according to the position of the float. Therefore, if the relationship between the flow velocity and the propagation time of ultrasonic waves is obtained in advance, the flow velocity can be known from the propagation time of ultrasonic waves.

Next, a case where the tubular portion 10 of the anemometer is attached with being inclined with respect to the vertical direction will be described. The buoyancy acting vertically on the float 12 from the lower side to the upper side and the gravity acting from the upper side to the lower side are almost equal to each other as in the case where the tubular portion 10 of the anemometer is arranged so as to be parallel to the vertical direction. To be done. Therefore, the force acting on the float 12 can be considered to be two, namely, the force due to the flow of the fluid acting along the tubular portion 10 and the elastic force due to the spring 16. Therefore, the float 12
Since the force acting on is the same as when the tubular portion 10 of the anemometer is arranged in the vertical direction, even if the tubular portion 10 of the anemometer is tilted, the flow velocity and the ultrasonic wave after the ultrasonic wave is transmitted are ultrasonic transducers. 1
4 does not change the relationship of the propagation time of ultrasonic waves until it is received.

When the tubular portion 10 of the anemometer is arranged horizontally, the two forces acting along the tubular portion 10 are the fluid flow force and the spring 16 elastic force. Therefore, even at this time, the relationship between the flow velocity and the propagation time of ultrasonic waves does not change. Thus, no matter how the tubular portion 10 of the anemometer is inclined with respect to the vertical direction or arranged horizontally, the flow velocity and the ultrasonic wave 1
The relationship between the two propagation times remains unchanged.

In the above embodiment, the elastic member such as the spring 16 is used as the urging means for exerting the force on the float 12 in the direction opposite to the flow direction of the fluid flowing through the tubular portion 10. However, instead of this, a magnet is used. It is also possible to use. In this case, the tubular part 1
The magnets are attached to the zero and the float 12 so that a force acts on the float 12 in the direction opposite to the flow direction of the fluid. For example, in FIG. 1, the spring 16 is removed and magnets are provided at both ends of the tubular portion 10 so that the S poles face each other with the tubular portion 10 interposed therebetween.
On the other hand, a magnet having a surface having the same shape as the upper surface 13 of the float 12 is attached to the float 12 so that the N pole faces the lower end side of the tubular portion 10. When the magnet is provided in the tubular portion and the float in this manner, the force acts on the float 12 in the direction opposite to the direction of fluid flow.

The shape of the magnet attached to the float 12 is not limited to this example, and it is sufficient that the magnet can be attached to the float. The float itself may be composed of a magnet. Further, in the above example, the polarities of the magnets may be reversed. Although magnets are provided at both ends of the tubular portion 10 in the above example, the magnets may be provided at either one of them. When a magnet is provided at the end of the tubular portion 10 near the fluid inlet 18, either the magnetic body such as iron is attached to the float or the float is made of such a magnetic body. May be. Even in this case, the force can be exerted on the float 12 in the direction opposite to the flow direction of the fluid.

In the above embodiment, the spring 16 is the tubular portion 10.
It is provided on the upper end side of the, but instead of this, a tension spring whose one end is attached to the portion opposite to the upper surface 13 of the float 12 and the other end is attached to the lower end of the tubular portion 10 is provided. You may However, when the tension spring is provided in this way, dust may be contained in the fluid entering from the inlet 18, and the dust may be caught by the tension spring and may not operate properly. Therefore, it is preferable to provide the spring 16 near the outlet 18. Also, float 1
2 may have any shape as long as the effective weight of the float 12 in the fluid is small, and may be a thin plate-like shape.

In the above embodiment, the shaft 22 and the spring 16 are used as the urging means for exerting a force on the float 12 in the direction opposite to the direction of fluid flow. The spring 16 exerts a force on the float 12, and the shaft 22 determines the direction of this force. When the shaft 12 is removed and the fluid 30 is caused to flow into the tubular portion 10, the spring 1 is pressed by the fluid 30 and the spring 16 is compressed.
6 has almost no deflection, and the float 12 attached to one end of the spring 16 is not pressed against the inner wall of the tubular portion 10. For example, the shaft 22 may be removed and only the spring 16 may be used as the biasing means. Further, if the diameter of the tubular portion 10 changes slowly and the spring 16 can be inserted close to the inner wall of the tubular portion 10, the spring 16 is supported by the inner wall of the tubular portion 10 even if the spring 16 is compressed without the shaft 22. Does not bend excessively. Therefore, also in this case, the shaft 22 can be removed, and the inner wall of the tubular portion 10 and the spring 16 function as a biasing means.

[0019]

As described above, as in the present invention, the velocity meter is provided with the biasing means for exerting a force on the float in the direction opposite to the direction of the flow of the fluid, thereby reducing the effective weight of the float in the fluid. As a result, the velocity meter using the ultrasonic transducer can be arranged in any direction without calibration, and the piping can be made more freely than before.

[Brief description of drawings]

FIG. 1 is a schematic partial cross-sectional view illustrating an example of a velocity meter according to the present invention.

FIG. 2 is a schematic partial cross-sectional view of a conventional velocity meter using an ultrasonic echo.

[Explanation of symbols]

 10,54 Tubular part 12,60 Float 13,60a Upper surface 14,24 Ultrasonic transducer 16 Spring 18 Inlet 20 Outlet 30,58 Fluid 56 Caliber

Claims (2)

[Claims] 1. A tubular part having a tapered diameter, a float inserted in the tubular part, an ultrasonic wave emitted toward the float, and an echo of the ultrasonic wave can be received. A velocity meter having an ultrasonic transducer arranged at one end of the tubular portion, characterized in that it has a biasing means for exerting a force on the float in a direction opposite to a flow direction of a fluid flowing through the tubular portion. A current meter. 2. When the fluid flows through the tubular portion, the float is stopped at a position where the force in the flow direction of the fluid exerted on the float by the flow of the fluid and the force of the biasing means are approximately balanced. The flowmeter according to claim 1, wherein the effective weight of the float in the fluid is 0 or is set to be appropriately small.