JP2003307445A - Ultrasonic flow meter - Google Patents

Abstract

(57) [Problem] To improve the measurement accuracy and reduce the size by eliminating the drift caused by the bending or reduction of the cross-sectional area of the flow path near the on-off valve in the flow path of the ultrasonic flow rate measuring means. SOLUTION: A joint pipe 23 provided between a measurement part of a measurement flow path 1 and a fluid introduction part provided with an on-off valve 23 and the like.
Is provided with means for suppressing drift. by this,
Since the drift generated on the upstream side does not affect the measurement portion, the degree of freedom in the design of the apparatus and the restriction on the piping conditions are reduced, and the measurement accuracy is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flow rate measuring device for measuring the flow rate and flow velocity of gas or liquid by ultrasonic waves.

[0002]

2. Description of the Related Art Heretofore, as an ultrasonic flow rate measuring device of this type, for example, JP-A-9-18591 and JP-A-11-
No. 3519926 is known, and FIG.
The example of -18591 gazette is shown. In FIG. 11, a pair of ultrasonic transmitters / receivers 2 and 3 are provided on the peripheral surfaces facing each other with the center line of the measurement flow path 1 through which the fluid to be measured flow and having a predetermined angle with respect to the center line. At the fluid inlet 4 of the passage 1, a rectifying body 6 composed of a plurality of thin tubes 5 arranged in parallel is provided in the same direction as the measurement passage 1. Then, ultrasonic waves are transmitted and received between the ultrasonic transceivers 2 and 3 in the forward and reverse directions with respect to the flow of the fluid, the flow velocity is measured from the propagation time difference in both directions, and the flow rate is calculated from the cross-sectional area of the pipe. There is. At this time, the flow entering the measurement flow path 1 is regulated by the thin tube 5 forming the rectifying body 6 so that the flow direction is the same direction as the measurement flow path 1 to reduce the inclination of the flow line in the measurement section, or to reduce the vortex. Is suppressed to reduce the fluctuation of the reception level of the ultrasonic wave due to the reflection and bending of the ultrasonic wave at the boundary surface of the flow turbulence, thereby preventing the deterioration of the measurement accuracy.

[0003]

However, in the above-mentioned conventional configuration, when used for actual measurement as shown in FIG. 12, the flow rate measuring device is miniaturized when the fluid of the measuring device is installed on the pipe. There are bending and thinning of the flow path at a short interval necessary for this, bending of the flow path of the on-off valve 23 part of the fluid introduction path 21 provided on the upstream side of the measurement portion, local cross-sectional area change, etc. Uneven flow tends to occur at the part. Especially when the measurement part is common and the piping conditions other than the above-mentioned measurement parts are designed according to the individual actual requirements, the rectifying body installed in the above-mentioned measurement flow path can be used to eliminate the complicated drift in each piping part. It becomes difficult to exert sufficient rectification effect.

That is, when the structure of the on-off valve of the introduction path or the bend of the pipe is largely different, the non-uniform flow also largely changes, and non-uniform flow or overflow occurs in the measurement flow path. However, there was a problem that the accuracy of flow rate measurement was lost due to disappearance. Especially, due to the design change in the introduction channel, the flow condition may change and the accuracy of flow rate measurement may be affected.

The present invention solves the above problems, and prevents the instability of the flow rate measurement accuracy due to the fact that the specifications of the flow passages in the introduction passage are different and the flow state leading to the inlet of the measurement flow passage is greatly different. The flow shape of the fluid flowing through the measurement flow path is improved by performing flow rectification or regulation and rectification of the flow direction before entering the measurement flow path inlet to improve the shape of piping such as the introduction path. The aim is to achieve high measurement accuracy regardless of the situation.

[0006]

In order to solve the above-mentioned conventional flow rate measuring device, the flow rate measuring device of the present invention has a structure in which an on-off valve, an introduction passage including a downstream passage of the on-off valve and a measurement flow passage are provided. A joint connecting portion is provided between the two, and a flow rectifying mechanism is provided at the joint connecting portion.

As a result, when the fluid flow passes through the on-off valve, it is bent at the on-off valve portion and collides with the facing wall surface of the flow path on the downstream side of the on-off valve, and the drift caused by the above-mentioned reasons is jointed. It is alleviated by the rectification mechanism of the part, and the fluctuation of the flow velocity distribution at the meter side flow path inlet is improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is characterized in that an inlet passage having an on-off valve and a fluid control means disposed on the downstream side of the on-off valve, and an inlet passage bent in the axial direction of the inlet passage. A measurement flow path provided, at least a pair of ultrasonic transceivers provided on opposite wall surfaces sandwiching the flow path of the measurement flow channel, and measurement control means for measuring the propagation time of ultrasonic waves between the pair of transceivers. In the ultrasonic flow rate measuring device comprising a calculation means for calculating a flow rate based on a signal from the measurement control means, a joint connection part is provided between both the fluid introduction part and the measurement part, and a fluid is provided inside the joint connection part. Inclusion of the control member enhances the flow rectification effect against the uneven flow generated in the introduction path,
Uneven distribution is suppressed and alleviated, and accurate flow path measurement becomes possible.

According to the second aspect of the present invention, since the fluid control member has porosity, the flow of the fluid flowing through the porous portion rectifies the flow having the uneven flow on the upstream side of the fluid control member.

According to the third aspect of the invention, the fluid control member comprises a plate-shaped member having a plurality of perforations, and the flow is once blocked by the plate-shaped member and then flows in the pores, so that the flow distribution is uniform. The uneven flow generated in the introduction path portion is suppressed.

According to a fourth aspect of the present invention, the fluid control member has a mesh shape, and the flow from the introduction passage is subdivided and uniformized by this fluid control member, and the drift caused at the introduction passage portion is suppressed. It

In a fifth aspect of the invention, the fluid control member is composed of a plurality of cylindrical lattices, and the lattice suppresses a drift in the lateral direction with respect to the flow in the joint passage.

In a sixth aspect of the present invention, since the fluid control member is provided so as to cover a part of the passage passage portion in the passage joint means pipe, the flow from the introduction portion is Since the flow once detours around the fluid control unit, a predetermined flow flows to the measurement unit regardless of the shape of the introduction path, and stable flow rate measurement is possible.

According to a seventh aspect of the present invention, a plurality of baffle plates are provided in the fluid passage portion of the flow path joint means in the flow direction, and even if there is a drift in the flow from the introduction passage, the baffle plates are used. The effect of suppressing the flow is to suppress uneven flow.

According to an eighth aspect of the present invention, the space of the fluid passage portion inside the flow path joint means is partitioned by a plurality of partition plates in the direction of the flow path, and the flow of the fluid in the fluid joint is restricted / suppressed. Therefore, uneven flow is less likely to occur.

[0016]

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

(Embodiment 1) FIGS. 1 and 2 are a sectional view and a partial top sectional view of an ultrasonic flow rate measuring apparatus according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 21 denotes an introduction path for the fluid to be measured, which is composed of an inlet 22, an opening / closing valve 23 of an electromagnetic type or a stepping motor type, and an opening / closing valve downstream side passage 24. The on-off valve downstream side flow path 24 is on the downstream side of the valve seat opening 26 of the on-off valve 23 and has a rectangular cross-sectional shape.

The opening / closing center line of the opening / closing valve 23 and the central axis of the opening / closing valve downstream side flow path 24 form an angle of approximately 90 degrees. Further, the valve seat opening 26 enters the opening / closing valve downstream side flow path 24 at the step 28 in order to reduce the mounting external dimension of the drive portion 27 of the opening / closing valve 23, and the valve seat opening 26 and the valve seat opening 2 are provided.
The space between the wall surface 29 and the wall surface 29 at a position facing 6 is narrowed, and the flow passage cross-sectional area of this portion is reduced.

The measurement path 30 comprises a bending portion 31, a measurement flow path inlet 4, a rectifying means 32 provided at the measurement flow path inlet 4, a measurement flow path 1, and a discharge bending portion 33. The bent portion 31 is the introduction path 2
1 is connected to the on-off valve downstream side flow passage 24, has a rectangular cross section, and has a recess 34 on the wall surface facing the on-off valve downstream side flow passage 24.
Is provided. The measurement flow path 1 is substantially perpendicular to the central axis of the open / close valve downstream flow path 24 of the introduction path 21.

The rectifying means 32 is composed of a flow direction regulating means 7 composed of a partition plate inclined in a desired direction according to the turbulence of the flow, and a fluctuation suppressing means 8 composed of a mesh having fine passages. There is.

The measurement flow path 1 has a rectangular cross section and is shown in FIG.
As shown in FIG. 5, a pair of ultrasonic transmitters / receivers 2, 3 are mounted on the wall surface in a direction perpendicular to the direction of the introduction path 21 so as to diagonally face each other on both the upstream side and the downstream side of the flow path with the flow path interposed therebetween. . Reference numeral 35 represents a rectified state of the fluid, and the flow velocity distribution in the flow path is represented in proportion to the length of the arrow. A discharge path 36 is connected to the discharge bending portion 33. The fluid to be measured flows out from the outlet 37 of the discharge path 36. The flow path 24 on the downstream side of the on-off valve, the measurement path 30, and the discharge path 36 of the introduction path 21 are U-shaped.

Reference numeral 38 denotes a measurement control means, which alternately transmits and receives ultrasonic waves between the ultrasonic transmitters and receivers 2 and 3 to set the difference in the propagation time of the ultrasonic waves in the forward and reverse directions with respect to the fluid flow at regular intervals. It has a function of placing it, measuring it, and outputting it as a propagation time difference signal. Further, 39 is a calculation means for receiving the propagation time difference signal from the measurement control means 38 and calculating the flow velocity and flow rate of the fluid to be measured. Further, 40 is a power supply means composed of a lithium battery or the like. Measurement control means 38, calculation means 3
9. A part of the power supply unit 40 and the drive unit 27 of the on-off valve 23 are mounted in the space inside the flow path of the fluid to be measured, which is formed in a U shape.

In the measuring device of the present invention, the introduction path 24 and the measurement path 1 described above are connected via a joint pipe 25. A fluid control means 41 is provided inside the joint pipe 25 in order to suppress a nonuniform flow generated in the introduction path.

Fluid control means 4 in Embodiment 1 of the present invention
1 is a substance in which a fluid suppressor for a fluid is filled in a fluid passageway with a porous fluid-permeable substance (for example, a sponge-like substance).

The operation and action of the ultrasonic flow rate measuring device configured as described above will be described below. First, the fluid to be measured flows from the inflow port 22 of the introduction path 21 through an external pipe (not shown). Further, the open / close valve 23 is opened, passes through the valve seat opening 26, hits the opposing wall 29 of the downstream passage 24 of the on / off valve, changes direction, and forms a drift along the opposing wall surface 29 to the fluid control means 25. Go to This uneven flow has a short distance between the valve seat opening 26 and the wall surface 29, and the narrower the flow passage cross-sectional area, the faster the flow velocity.

The non-uniform flow flows into the joint pipe 25, diffuses over the entire surface inside the pipe, is rectified by the fluid control means 41, the non-uniform flow is suppressed, and flows into the downstream measurement flow path. The ultrasonic waves transmitted from one of the pair of ultrasonic wave transmitters / receivers provided on the wall surface of the measurement flow path 1 are affected by the flow velocity of the fluid to be measured, and propagate fast in the forward direction and in the reverse direction to the flow. When it propagates to, it is late and is received by the other transceiver. The transmission / reception of this ultrasonic wave is controlled by the measurement control means 38 and is alternately performed between the pair of ultrasonic wave transmitters / receivers 2, 3 and is converted into an electric signal, and the measurement control means 38 reverses the forward direction of the fluid flow. Is converted into the propagation time of ultrasonic waves in the direction. Since the propagation time difference is proportional to the fluid flow velocity, this is transmitted to the computing means 39. The calculation means 39 calculates the flow rate or flow rate of the fluid to be measured by calculating the signal from the measurement control means 38, the cross-sectional area of the measurement flow path stored therein, and the coefficient peculiar to the device.

As described above, in this embodiment, the joint pipe 25 is provided in the flow passage 24 on the downstream side of the on-off valve of the introduction passage 21 and the measurement passage, so that the flow passage of the valve seat opening portion of the on-off valve 23 is provided. The effect of suppressing the non-uniform flow generated in 1. occurs, the flow of the fluid in the measurement flow path 1 can be improved, and the measurement accuracy of the ultrasonic measurement device can be improved.

Further, in the present embodiment, the design of the upstream side of the measuring portion is changed, the shape of the introduction path is largely changed, the state of the fluid flow is changed, and even if the non-uniform flow state is changed, the flow flows into the measurement portion. Prior to the operation, since the drift can be suppressed by the rectifying action of the joint pipe 25 portion, the degree of freedom in changing the design of the measuring device can be increased without affecting the measurement performance.

(Embodiment 2) FIG. 3 is a sectional view of a joint pipe 25 of an ultrasonic flow rate measuring apparatus according to Embodiment 2 of the present invention. The other parts of the ultrasonic flow rate measuring device are the same as those in FIG. In FIG. 3, reference numeral 42 is a fluid control means which is an example of the fluid control control means 41 of FIG. FIG. 4 shows the fluid control means 4
A hole 43 is provided on the entire surface of the plate-shaped member in a view of 2 viewed from above. The size of the holes 43 and the installation density are experimentally determined by the flow rate of the flow passage and the size of the drift.

In the ultrasonic flow rate measuring device configured as described above, the fluid to be measured which has passed through the valve seat opening 26 of the on-off valve 23 and collided with the facing wall 29 flows downstream along the wall surface, It corresponds to the fluid control means 42 which is a plate-shaped member. When a fluid passes through the hole 43 provided in the fluid control means 42, an excessive flow rate is prevented from flowing due to the passage resistance, so that the uneven flow is diffused along the upstream surface of the fluid control means 42, and the hole 43 provided on the entire surface. Flowing in the flow control means a weak drift on the downstream side of the fluid control means 42.

(Embodiment 3) An ultrasonic flow rate measuring apparatus according to Embodiment 3 of the present invention will be described. The other parts of the ultrasonic flow rate measuring device are the same as those in FIG. FIG. 5 is a view of a fluid control member 44 corresponding to the fluid control means 42 of FIG. 3 in the second embodiment as viewed from above, and 44 is a fluid composed of a wire mesh member which is an example of the fluid control control means 41 of FIG. Since it is a control means and is a wire mesh member, it has a certain number of holes on the entire surface. The size of the holes and the installation density are experimentally determined by the flow rate of the flow passage and the size of the drift.

In the ultrasonic flow rate measuring device configured as described above, the fluid to be measured which has passed through the valve seat opening 26 of the on-off valve 23 and collides with the facing wall 29 flows downstream along the wall surface, It corresponds to the fluid control means 44. When a fluid passes through the hole of the wire mesh which is the fluid control means 44, a passage resistance is generated and an excessive flow rate is prevented from flowing, so that the uneven flow is diffused along the upstream surface of the fluid control means 44, and the entire fluid control means is formed. The fluid flows through the holes of the above, and a weak nonuniform flow is provided on the downstream side of the fluid control means 44.

(Embodiment 4) FIG. 6 is a sectional view of a fluid control means of an ultrasonic flow rate measuring apparatus according to Embodiment 4 of the present invention. The other parts of the ultrasonic flow rate measuring device are the same as those in FIG. In FIG. 6, reference numeral 45 is an example of the fluid control control means 41 of FIG. 1, which is a product in which a plurality of tubular lattices are housed in the joint pipe 25 flow path. FIG. 7 is a view of the fluid control means 45 seen from above, and a hole 46 having a hexagonal cross section is provided on the entire surface of the flow path.

In the ultrasonic flow rate measuring device constructed as described above, the fluid to be measured which has passed through the valve seat opening 26 of the on-off valve 23 and collided with the facing wall 31 flows downstream along the wall surface, The uneven flow is diffused in the fluid control means 45, and the fluid flows evenly through the holes 46 provided in the entire surface of the fluid control means 45, so that a very weak uneven flow is formed on the downstream side of the fluid control means 45. Further, since the cylinder of the fluid control means aligns the flow of the fluid in the direction of the flow path, there is no lateral vector in the flow, and it functions to prevent the occurrence of turbulence, turbulence and other turbulence in the flow. Next, the fluid control means 45 is an aggregate of cylinders having a length in the flow direction, such as a triangle, a quadrangle, a circle, etc., in addition to the cylinder having a hexagonal lattice as shown in FIG. If present, it is included in the tubular lattice.

(Fifth Embodiment) FIG. 8 is a sectional view of a fluid control means of an ultrasonic flow rate measuring apparatus according to a fifth embodiment of the present invention. The other parts of the ultrasonic flow rate measuring device are the same as those in FIG. In FIG. 8, a blocking plate 48 is attached so as to block a part of the flow path, and a part of the flow from the introduction path collides with this blocking plate 48, and therefore flows along the blocking plate 48 and blocks. Since it flows around the lower part of the plate 48 to the lower part, even if a non-uniform flow occurs in the introduction path, the blocking plate 48
When it hits, the drift is diffused and the drift of the flow can be eliminated.

(Sixth Embodiment) FIG. 9 is a sectional view of a fluid control means of an ultrasonic flow rate measuring apparatus according to a sixth embodiment of the present invention. The other parts of the ultrasonic flow rate measuring device are the same as those in FIG. In FIG. 9, a plurality of baffle plates 49 are installed in the fluid passage portion in the joint pipe 25 at a predetermined distance from the pipe wall in a direction that becomes a resistance against the flow direction.

In order for the flow from the introduction passage to pass through the joint pipe 25, it has to pass slightly through this baffle plate, which serves as a resistance against the passage of fluid and has the effect of suppressing the uneven flow generated in the introduction passage.

(Embodiment 7) FIG. 10 is a sectional view of a fluid control means of an ultrasonic flow rate measuring apparatus according to Embodiment 7 of the present invention. The other parts of the ultrasonic flow rate measuring device are the same as those in FIG. In the fluid passage portion of the joint pipe 25,
A partition plate 50 is provided in the flow path direction, and the flow from the introduction path passes through this joint pipe 25, so that the uneven flow in the flow path pipe is dispersed by each partition plate 50 and flows along the partition plate 50. As a result, the flow becomes extremely weak on the downstream side of the fluid control unit 45. Further, since the partition of the fluid control means aligns the flow of the fluid in the direction of the flow path, there is no lateral vector in the flow, and it functions to prevent the occurrence of turbulence such as turbulence and vortex.

[0040]

As described above, according to the first to eighth aspects of the present invention, the strong drift that occurs near the valve seat opening of the on-off valve upstream of the fluid control means is suppressed and eliminated. Since it is possible to reinforce the function of the rectifying means provided at the inlet of the measurement flow channel to rectify the fluid flowing in the measurement flow channel,
Even if there is a change in the design of the fluid flow path or a difference in specifications, the measurement performance of the measurement part is not affected, and the ultrasonic flow rate measuring device can be downsized and its accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an ultrasonic flow rate measuring device according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway top view of the device.

FIG. 3 is a sectional view showing a joint pipe of an ultrasonic flow rate measuring device according to a second embodiment of the present invention.

FIG. 4 is a plan view showing a joint pipe of a fluid control means of the device.

FIG. 5 is a plan view showing a joint pipe of a fluid control means of an ultrasonic flow rate measuring device according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing a joint pipe of an ultrasonic flow rate measuring device according to a fourth embodiment of the present invention.

FIG. 7 is a plan view of a fluid control means of the device.

FIG. 8 is a sectional view showing a joint pipe of an ultrasonic flow rate measuring device according to a fifth embodiment of the present invention.

FIG. 9 is a sectional view showing a joint pipe of an ultrasonic flow rate measuring device according to a sixth embodiment of the present invention.

FIG. 10 is a sectional view showing a joint pipe of an ultrasonic flow rate measuring device according to a seventh embodiment of the present invention.

FIG. 11 is a top view of a rectifying unit and a measurement flow path of a conventional ultrasonic flow rate measuring device.

FIG. 12 is a sectional view of a flow path of another conventional ultrasonic flow rate measuring device.

[Explanation of symbols]

1 measurement channel A couple of ultrasonic transceivers 4 Measurement channel inlet 21 Introduction route 23 Open / close valve 24 Open / close valve downstream flow path 25 joint pipe 38 measurement control means 39 computing means 41 fluid control means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeru Iwanaga             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Yoshinori Inui             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 2F030 CF01                 2F031 AB09                 2F035 DA19

Claims (8)

[Claims] 1. A flow for joining an introduction path having an on-off valve, at least a pair of ultrasonic transmitter-receivers provided on opposite wall surfaces of the measurement flow path, and a rear end of the introduction path and an inlet section of the measurement flow path. A path joint means, a fluid control member provided in a fluid passage portion of the flow path joint means, a measurement control means for measuring the propagation time of ultrasonic waves between the ultrasonic transmitters and receivers, and a signal from the measurement control means. An ultrasonic flow rate measuring device, comprising: an arithmetic means for calculating a flow rate based on the flow rate. 2. The fluid control member has porosity.
The ultrasonic flow rate measuring device described. 3. The ultrasonic flow rate measuring device according to claim 2, wherein the fluid control member is a plate-shaped member. 4. The ultrasonic flow rate measuring device according to claim 2, wherein the fluid control member is a member having a mesh structure. 5. The ultrasonic flow rate measuring device according to claim 2, wherein the fluid control member comprises a plurality of cylindrical lattices. 6. The ultrasonic flow rate measuring device according to claim 1, further comprising a fluid control member which covers a part of the passage passage portion of the passage joint means so as to shield the passage passage portion. 7. The ultrasonic flow rate measuring device according to claim 1, wherein a plurality of baffle plates are provided in a pipe line of the flow path joint means in a direction against a flow of fluid. 8. The ultrasonic flow rate measuring device according to claim 1, wherein the inside of the passage through which the fluid of the flow passage joint means passes is partitioned by a plurality of partition plates in the fluid flow direction.