JP2004061269A - Ultrasonic flow rate measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate a stable flow speed distribution in a measuring flow path and enhance measuring accuracy regardless of a shape of an inflow pipeline coupled to the measuring flow path. <P>SOLUTION: An ultrasonic flow rate measuring apparatus is provided with the measuring flow path 5 for making a test fluid flow, a lead-in 11 and a lead-out 12 provided on an upstream side and a downstream side of the measured flow path 5, at least a pair of ultrasonic transducers 7, 8 provided and propagating ultrasonic waves through the measured flow path 5, an entrance enlarging space 19 provided on an upstream side of the lead-in 11 and an entrance protrusion element 20 having a protrusion 22 connected to the lead-in and protruding into the entrance enlarging space 19 and an entrance opening 23 provided in the protrusion 22. The measuring accuracy is enhanced by supplying a stable flow to the measuring flow path 5 regardless of the shape of the inflow pipeline. <P>COPYRIGHT: (C)2004,JPO

Description

[Claims]
1. A measurement flow path through which a fluid to be measured flows , an introduction portion provided upstream of the measurement flow path, and at least a pair of ultrasonic transceivers provided so that ultrasonic waves propagate through the measurement flow path. An entrance-side enlarged space provided on the upstream side of the introduction portion, an entrance-side projection provided with an entrance opening in a projection connected to the introduction portion and projected to the entrance-side enlarged space, An ultrasonic flow rate measuring device comprising: a flow rate calculating means for transmitting / receiving an ultrasonic wave between ultrasonic transmitter / receivers and calculating a flow rate based on the transmitted / received signal , wherein the protrusion is provided so as to rectify the flow.
2. The apparatus according to claim 1, wherein an inlet opening is provided at a position that does not face the inlet of the enlarged space on the inlet side to prevent the fluid to be measured from flowing directly from the inlet into the inlet opening. Ultrasonic flow meter.
3. A measurement flow path through which a fluid to be measured flows, an introduction section and an output section provided on the upstream and downstream sides of the measurement flow path, and at least an ultrasonic wave propagates through the measurement flow path. A pair of ultrasonic transceivers, an entrance-side enlarged space provided upstream of the introduction section, an exit-side enlarged space provided downstream of the outlet section, and the entrance-side enlarged connected to the introduction section. An inlet-side protruding body provided with an inlet opening in a protruding part protruding into the space, and an outlet-side protruding body provided with an outlet opening in a protruding part connected to the outlet part and protruding into the outlet-side enlarged space part And an ultrasonic flow rate measuring device that transmits and receives ultrasonic waves between the ultrasonic transceivers and calculates a flow rate based on the transmitted and received signals , wherein the protrusion is provided to rectify the flow. .
4. A measurement flow path through which a fluid to be measured flows, an introduction portion provided upstream of the measurement flow path, and at least one pair of ultrasonic transceivers provided so that ultrasonic waves propagate through the measurement flow path. And an entrance-side enlarged space provided on the upstream side of the introduction section, an entrance-side projection provided with an entrance opening in a projection protruding from the entrance-side enlarged space, and between the ultrasonic transceiver. An ultrasonic wave transmission means for transmitting and receiving ultrasonic waves and calculating a flow rate based on the transmission and reception signals, and an inflow direction changing means for changing the flow direction of the fluid to be measured flowing into the inlet opening and inflowing the measured fluid Flow measurement device.
5. A measurement flow path through which a fluid to be measured flows, an introduction section and an output section provided upstream and downstream of the measurement flow path, and at least an ultrasonic wave propagates through the measurement flow path. A pair of ultrasonic transceivers, an entrance-side enlarged space provided upstream of the introduction section, an exit-side enlarged space provided downstream of the outlet section, and the entrance-side enlarged connected to the introduction section. An inlet-side protruding body provided with an inlet opening in a protruding part protruding into the space, and an outlet-side protruding body provided with an outlet opening in a protruding part connected to the outlet part and protruding into the outlet-side enlarged space part And a flow rate calculating means for transmitting / receiving ultrasonic waves between the ultrasonic transmitter / receivers and calculating a flow rate based on the transmission / reception signals, and a flow direction of the fluid to be measured flowing into the inlet opening and the outlet opening. ultrasonic flow provided the inflow direction changing means for flowing by changing the Measuring apparatus.
6. The inlet-side expansion space is ultrasonic flow measuring device according to any one of claims 1 to 5 disposed directly after the fluid control means for controlling the flow rate of the fluid to be measured.
7. The ultrasonic flow measuring device according to any one of claims 1 to 6 arranged flow regulating body on the inlet side projecting member.
8. The ultrasonic flow rate measuring device according to claim 3, wherein a flow restricting member is arranged on the inlet-side protrusion and the outlet-side protrusion.
9. A inlet-side projecting member and an outlet side projecting member, ultrasonic flow measuring device according to claim 8 inlet and outlet sides of the flow restriction member is that the same or substantially the same shape.
10. The ultrasonic flow rate measuring device according to any one of claims 1 to 9 in the introduction and deriving unit arranged bent portions bending the flow direction.
11. A measurement flow path through which a fluid to be measured flows, an introduction portion provided upstream of the measurement flow path, and at least a pair of ultrasonic transceivers provided so that ultrasonic waves propagate through the measurement flow path. An entrance-side enlarged space provided on the upstream side of the introduction portion, an entrance-side projection provided with an entrance opening in a projection connected to the introduction portion and projected to the entrance-side enlarged space, Flow rate calculating means for transmitting / receiving ultrasonic waves between the ultrasonic transmitter / receivers and calculating a flow rate based on the transmitted / received signals, wherein the flow from the inlet to the inlet-side enlarged space portion changes direction to open the inlet. An ultrasonic flow rate measuring device that flows into the hole, is rectified in the projecting portion, flows into the introduction portion, and is supplied to the measurement flow path.
DETAILED DESCRIPTION OF THE INVENTION
[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a flow rate measuring device for measuring a flow rate and a flow rate of a gas or a liquid.
[0002]
[Prior art]
Conventionally, for example, Japanese Unexamined Patent Application Publication No. 11-351926 is known as this type of ultrasonic flow rate measuring device. As shown in FIG. An upstream ultrasonic transmitter / receiver 2a and a downstream ultrasonic transmitter / receiver 2b are provided at a predetermined angle with respect to the flow direction of the measurement flow path 1, and these ultrasonic transmitters / receivers 2a and 2b A rectifier 4 is provided on the inlet side of the measurement flow channel 1 while being housed in the concave portions 3 a and 3 b provided in the passage 1. Then, the flow velocity of the fluid flowing through the measurement channel 1 is transmitted and received between the ultrasonic transmitters / receivers 2a and 2b to measure the propagation time difference, and the flow rate is calculated from the cross-sectional area of the measurement channel 1. At this time, the flow entering the measurement flow path 1 is regulated by the rectifier 4 to reduce the inclination of the streamline in the measurement section or to suppress the generation of vortices, and the ultrasonic wave at the boundary surface of the turbulence of the flow. Fluctuations in the reception level of ultrasonic waves due to reflection and refraction are reduced to prevent deterioration in measurement accuracy.
[0003]
[Problems to be solved by the invention]
However, in the conventional configuration, the inflow state into the measurement flow path 1 slightly changes depending on the pipe shape upstream of the rectifier 4, and a difference occurs in the flow velocity distribution in the measurement flow path 1. There was a problem that accuracy varied.
[0004]
An object of the present invention is to solve the above-mentioned problem, and to generate a stable flow velocity distribution in a measurement flow channel regardless of the shape of an inflow conduit to the measurement flow channel, and to improve measurement accuracy.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a measurement flow path through which a fluid to be measured flows, an inlet and an outlet provided on the upstream and downstream sides of the measurement flow path, and ultrasonic waves propagate through the measurement flow path. At least a pair of ultrasonic transceivers provided as described above, an entrance-side enlarged space provided upstream of the introduction section, and an entrance opened to a projection connected to the introduction section and projected into the entrance-side enlarged space. An inlet-side projecting body provided with a hole, and a flow rate calculating means for transmitting and receiving ultrasonic waves between the ultrasonic transceivers and calculating a flow rate based on the transmitted and received signals, and the projecting portion is provided to rectify the flow. It is a thing.
[0006]
According to the above invention, a stable flow can be supplied to the measurement flow path by stabilizing the flow state of the fluid by expanding the passage volume by the inlet-side enlarged space portion and allowing the fluid to flow from the inlet opening of the projecting body. Stable flow can be supplied to the measurement flow channel by securing the approach length to the introduction part of the measurement flow channel by the projecting body protruding into the enlarged space, and stable regardless of the shape of the pipe on the inflow side The flow can be supplied to the measurement channel to improve the measurement accuracy. Further, by arranging the protruding body in the entrance-side enlarged space, the size of the conduit can be reduced.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the embodiment of the present invention, the measurement flow path through which the fluid to be measured flows , an introduction portion provided on the upstream side of the measurement flow path, and at least one pair of the measurement flow paths provided so that ultrasonic waves propagate. An ultrasonic transmitter / receiver, an entrance-side enlarged space provided upstream of the introduction section, and an entrance-side projection provided with an entrance opening at a projection connected to the introduction section and projected into the entrance-side enlarged space. A body, and a flow rate calculating means for transmitting and receiving ultrasonic waves between the ultrasonic transmitter / receiver and calculating a flow rate based on the transmitted / received signals , wherein the protrusion is provided to rectify the flow .
Further, by providing the inlet opening at a position that does not face the inlet of the inlet-side enlarged space, the measured fluid is prevented from flowing directly from the inlet into the inlet opening.
The stable flow state can be supplied to the measurement flow path by stabilizing the flow state of the fluid by expanding the passage volume by the inlet-side enlarged space and flowing the fluid through the inlet opening of the protruding body. A stable flow can be supplied to the measurement flow channel by securing the approach length to the introduction part of the measurement flow channel with the protruding protrusion, and a stable flow can be measured regardless of the shape of the conduit on the inflow side. It can be supplied to the road to improve the measurement accuracy. Further, by arranging the protruding body in the entrance-side enlarged space, the size of the conduit can be reduced.
[0008]
Also , a measurement flow path through which the fluid to be measured flows , an introduction section and an output section provided on the upstream and downstream sides of the measurement flow path, and at least one pair of ultrasonic waves provided so that ultrasonic waves propagate through the measurement flow path A transceiver, an entrance-side enlarged space provided on the upstream side of the introduction section, an exit-side enlarged space provided on the downstream side of the lead-out section, and connected to the introduction section and protruding into the entrance-side enlarged space. An inlet-side protruding body provided with an inlet opening in the protruded portion; an outlet-side protruding body provided with an outlet opening in a protruding portion connected to the outlet portion and protruding into the outlet-side enlarged space; Flow rate calculating means for transmitting and receiving ultrasonic waves between the sound wave transmitters and receivers and calculating a flow rate based on the transmitted / received signals , wherein the protrusions are provided so as to be rectified .
[0009]
In the case of forward flow, a stable flow can be supplied to the measurement flow channel by securing the pipeline volume and the approach length by the inlet-side enlarged space and the inlet-side projection, and in the case of reverse flow, the outlet-side enlarged space A stable flow is supplied to the measurement flow path by securing the pipeline volume and the approach length by the section and the exit side protrusion, and stable regardless of the upstream or downstream pipe shape in either forward or reverse flow state The flow can be supplied to the measurement flow path to improve the measurement accuracy, and the measurement accuracy can be stabilized for the flow in both the forward and reverse directions, and a highly convenient device having no installation direction can be realized. Furthermore, even when there is a pulsation that causes a reverse flow in the flow, the measurement accuracy can be improved in both forward and reverse flow states during the pulsation.
[0010]
Further , the inlet opening is provided with an inflow direction changing means for changing the flow direction and inflowing. And even when the position of the inflow port to the inlet side enlarged space part is different, a stable flow is given to the inlet opening and supplied to the measurement flow path, so that the measurement accuracy can be improved. Further, the degree of freedom in setting the position of the inflow port to the inlet-side enlarged space can be improved, and the apparatus can be reduced in size or can be designed to be easily manufactured, and the cost can be reduced.
[0011]
Further , the inlet opening and the outlet opening are provided with inflow direction changing means for changing the flow direction and inflowing. Further, a more stable flow can be supplied to the flow in both the forward and reverse directions by the measurement flow path, and the measurement accuracy can be improved.
[0012]
The enlarged space on the inlet side is disposed immediately after the fluid control means for controlling the flow rate of the fluid to be measured. Then, the disturbance of the flow by the fluid control means is reduced by the inlet-side enlarged space portion, and a stable flow is given to the inlet-side protruding body and supplied to the measurement flow path to improve the measurement accuracy. In addition, even when the shape and the mounting position of the fluid control means are different, the difference in the flow is reduced by the inlet-side enlarged space portion, and a stable flow is given to the inlet-side protruding body and supplied to the measurement flow path, so that the measurement accuracy can be improved. In addition, the degree of freedom in designing the shape and mounting position of the fluid control means is high, and the productivity can be improved.
[0013]
In addition , a flow restricting body is arranged on the inlet-side protruding body. And the flow to the introduction part of the measurement flow path can be further stabilized by the flow restricting body provided on the inlet side projection, and the measurement accuracy can be further improved.
[0014]
Further , a flow restricting body is arranged on the inlet-side protrusion and the outlet-side protrusion. In addition, the flow flowing into the measurement flow path can be further stabilized for the flow in either the forward or reverse direction, and the measurement accuracy can be further improved. In addition, even when there is a pulsation that causes a reverse flow in the flow, the flow flowing into the measurement flow path can be further stabilized and the measurement accuracy can be improved in both the forward and reverse flow states during the pulsation.
[0015]
The inlet-side protrusion and the outlet-side protrusion have the same or substantially the same shape as the inlet-side and outlet-side flow restrictors. In addition, stabilize the flow flowing into the measurement flow path for both forward and reverse flow directions, make the flow velocity distribution in the measurement flow path almost the same, and make the measurement characteristics uniform for both forward and reverse flow directions. The measurement accuracy can be further improved. Furthermore, even when there is a pulsation that causes a reverse flow in the flow, the flow flowing into the measurement flow path can be further stabilized and the measurement accuracy can be improved in both the forward and reverse flow states during the pulsation.
[0016]
In addition , a bent portion that bends the flow direction is disposed in the introduction portion and the lead-out portion. Further, by arranging the bent portion, it is possible to further reduce the size of the apparatus, and increase the stability of the flow to the measurement flow path by the entrance side or the exit side enlarged space portion and the entrance side or the exit side protrusion to perform the measurement. Accuracy can be improved.
Further, a measurement channel through which the fluid to be measured flows , an introduction portion provided on the upstream side of the measurement channel, and at least one pair of ultrasonic transceivers provided so that ultrasonic waves propagate through the measurement channel, An inlet-side enlarged space provided on the upstream side of the introduction unit, an entrance-side protrusion provided with an entrance opening in a protrusion connected to the introduction unit and projected into the entrance-side enlarged space, and Flow rate calculating means for transmitting and receiving ultrasonic waves between the vessels and calculating a flow rate based on the transmitted and received signals, wherein the flow from the inlet to the inlet-side enlarged space portion changes direction and flows into the inlet opening. The flow is rectified in the projecting portion, flows into the introduction portion, and is supplied to the measurement flow path. Then, a stable flow can be supplied to the measurement flow path regardless of the shape of the conduit on the inflow side, and the measurement accuracy can be improved.
[0017]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
(Example 1)
FIG. 1 is a longitudinal sectional view of an ultrasonic flow rate measuring device according to a first embodiment of the present invention. In the figure, 5 is a measurement flow channel surrounded by a flow channel wall 6, and 7 and 8 are upstream and downstream ultrasonic transceivers mounted on the flow channel wall 6 so as to face each other. The upstream ultrasonic transmitter / receiver 7 and the downstream ultrasonic transmitter / receiver 8 are separated from each other by a distance L so as to cross the width W direction of the measurement flow channel 5 and inclined at an angle θ with respect to the flow direction of the fluid in the measurement flow channel 5. Installed. Reference numerals 9a and 9b denote opening holes on the upstream side and the downstream side, respectively, which allow the ultrasonic transceivers 7 and 8 to face the measurement flow path 5. Reference numeral 10 denotes an ultrasonic wave propagation path (indicated by a two-dot chain line) in which the ultrasonic waves transmitted between the opposing ultrasonic wave transmitters / receivers 7 and 8 propagate directly to the other party. Reference numeral 11 denotes an introduction portion provided on the upstream side of the measurement flow path 5 and serving as an inlet of the fluid to be measured into the measurement flow path 5; This is an outlet that serves as an exit. Reference numeral 13 denotes an upstream bent portion connecting the measurement flow path 5 and the introduction portion 11, and reference numeral 14 denotes a downstream bent portion connecting the measurement flow channel 5 and the lead-out portion 12. Although the bent portions 13 and 14 are shown bent in the width W direction of the measurement flow path 5, it is needless to say that the bent direction can be any direction.
[0019]
Reference numeral 15 denotes a flow stabilizing means provided on the upstream side of the ultrasonic wave propagation path 10 and includes a lattice-shaped direction regulating portion 15a for adjusting a flow direction and a fluctuation suppressing portion 15b formed of a mesh such as a mesh for reducing flow velocity fluctuation. ing. A flow rate calculation 16 includes a measurement control unit 17 connected to the ultrasonic transceivers 7 and 8 for transmitting and receiving ultrasonic waves, and a calculation unit 18 for calculating a flow rate based on a signal from the measurement control unit 17 and calculating a flow rate. Means.
[0020]
Reference numeral 19 denotes an entrance-side enlarged space disposed upstream of the introduction unit 11. Reference numeral 20 denotes an entrance-side protrusion inserted into the entrance-side enlarged space 19. The inlet-side protruding body 20 includes a protruding portion 22 protruding from the inlet-side mounting surface 21 of the flow path wall 6, and an inlet opening 23 provided with a hole in a part of the protruding portion 22. Reference numeral 24 denotes an inlet to the inlet-side enlarged space 19, and the inlet opening 23 and the inlet 24 are arranged so as not to directly face each other. Numeral 25 is a fluid control means for controlling the flow rate of the fluid to be measured which is arranged opposite to the inflow port 24. The fluid control means 25 includes a drive section 26 and a valve section 27 which faces the inflow port 24. Reference numeral 28 denotes a connection port provided on the upstream side of the inflow port 24, and reference numeral 29 denotes a connection port communicating with the lead-out section 12.
[0021]
Numeral 30 denotes a flow restricting member provided on the inlet-side protruding body 20, which is formed by a grid-like direction restricting portion 30a for adjusting the flow direction of the flow flowing from the inlet opening 23, and a mesh-like body such as a mesh to reduce flow velocity fluctuation. Is provided with the fluctuation suppressing unit 30b arranged as described above.
[0022]
Reference numeral 31 denotes an inflow suppressing body for reducing the flow of fluid into the opening holes 9a and 9b, which is provided flush with the flow path wall 6 and has fine holes through which ultrasonic waves can pass.
[0023]
Next, the operation of the ultrasonic flow measurement device will be described. The fluid to be measured entered from the connection port 28 passes through the inflow port 24 and flows into the entrance-side enlarged space 19 when the valve portion 27 of the fluid control means 25 is opened. The turbulent flow passing through the valve portion 27 is adjusted in the space where the volume of the inlet-side enlarged space portion 19 is increased, and the inlet opening of the inlet-side protrusion 20 provided at a position not opposed to the inlet 24. It flows into the protruding part 22 from the hole 23, and becomes a flow rectified by a sufficient approach distance of the inlet-side protruding body 20 and flows into the introduction part 11 provided on the upstream side of the measurement flow path 5. In addition, the flow passes through the flow restricting body 30 provided on the inlet-side protruding body 20, and the flow is rectified by the flow direction rectification by the lattice-shaped direction restricting section 30a and the flow velocity fluctuation is reduced by the fluctuation suppressing section 30b formed by the mesh body. It is further stabilized and flows into the introduction section 11. Although the flow entering the introduction portion 11 is bent at the bent portion 13, the flow flowing into the introduction portion 11 is stable, so that the variation in the flow state is kept small even after the bending, and the flow stabilizing means. The flow velocity distribution is further stabilized by a lattice-shaped direction regulating part 15a for adjusting the flow direction in 15 and a fluctuation suppressing part 15b formed of a mesh such as a mesh for reducing the flow velocity fluctuation, so that the flow velocity distribution is less affected by the difference on the upstream side. It is formed in the ultrasonic wave propagation path 10 of the measurement flow path 5.
[0024]
Next, the flow measurement operation using ultrasonic waves will be described. In the measurement channel 5, the transmission and reception of ultrasonic waves are performed between the ultrasonic transceivers 7 and 8 across the width W of the channel cross section of the measurement channel 5 by the operation of the measurement control unit 17. That is, the propagation time T1 until the ultrasonic wave emitted from the upstream ultrasonic transceiver 7 is received by the downstream ultrasonic transceiver 8 is measured. On the other hand, the propagation time T2 until the ultrasonic wave emitted from the downstream ultrasonic transceiver 8 is received by the upstream ultrasonic transceiver 7 is measured. Based on the propagation times T1 and T2 measured in this manner, the flow rate is calculated by the calculation unit 18 by the following calculation formula.
[0025]
Now, the angle between the flow velocity V of the fluid to be measured in the flow direction of the measurement flow path 5 and the ultrasonic wave propagation path 10 is θ, the distance between the ultrasonic transceivers 7 and 8 is L, and the sound velocity of the fluid to be measured is C. Then, the flow velocity V is calculated by the following equation.
[0026]
T1 = L / (C + Vcosθ)
T2 = L / (C−Vcos θ)
V = (L / 2 cos θ) ((1 / T1) − (1 / T2)) by eliminating the sound velocity C from the formula for subtracting the reciprocal of T2 from the reciprocal of T1.
Since θ and L are known, the flow velocity V can be calculated from the values of T1 and T2.
[0027]
From the flow velocity V and the cross-sectional area S orthogonal to the flow direction of the measurement flow path 5, the flow rate Q is given by Q = KVS
Here, K is a correction coefficient in consideration of the flow velocity distribution in the cross-sectional area S, and the flow rate can be obtained in this manner.
[0028]
As described above, the flow state of the fluid is stabilized by the passage volume expansion by the inlet-side enlarged space portion 19 , and the stable flow can be supplied to the measurement flow path 5 by flowing the fluid from the inlet opening 23 of the protrusion 20. A stable flow can be supplied to the measurement flow path 5 by securing the approach length of the measurement flow path 5 to the introduction section 11 by the protruding body 20 protruding from the entrance-side enlarged space portion 19 , and the flow path shape on the inflow side Irrespective of the above, a stable flow can be supplied to the measurement flow path 5 to improve the measurement accuracy. Further, by disposing the protruding body 20 in the entrance-side enlarged space 19 , the size of the conduit can be reduced.
[0029]
In addition, the disturbance of the flow by the fluid control unit 25 is reduced by the inlet-side enlarged space portion 19 , and a stable flow is given to the inlet-side protruding body 20 and supplied to the measurement flow path 5 to improve the measurement accuracy. Even when the fluid control means 25 has a different shape or a different mounting position, the difference in the flow is reduced by the inlet-side enlarged space portion 19 and a stable flow is given to the inlet-side protruding body 20 and supplied to the measurement flow path 5 so that the measurement accuracy is improved. , And the degree of freedom in designing the shape and mounting position of the fluid control means 25 is high, so that productivity can be improved.
[0030]
In addition, the flow restricting body 30 provided on the inlet-side protruding body 20 can further stabilize the flow of the measurement flow path 5 to the introduction portion 11 , and can further improve the measurement accuracy.
[0031]
Further, the arrangement of the bent portions 13 and 14 can further reduce the size of the apparatus, and the stability of the flow to the measurement flow path 5 is increased by the enlarged space on the inlet or outlet side and the protrusion on the inlet or outlet side. And the measurement accuracy can be improved.
[0032]
Although it described as a flow restriction member 30 of the grid-shaped or mesh-like, fine perforated plate, C D cammed, non-woven fabric, such as cotton-like that available course.
[0033]
(Example 2)
Second Embodiment FIG. 2 is a cross-sectional view of an ultrasonic flow measuring device according to a second embodiment of the present invention. 2, the same members and the same functions as those of the embodiment of FIG. 1 are denoted by the same reference numerals, detailed description thereof will be omitted, and different portions will be mainly described.
[0034]
Reference numeral 32 denotes an outlet-side enlarged space disposed downstream of the outlet 12. Reference numeral 33 denotes an outlet-side protrusion inserted into the outlet-side enlarged space 32. The outlet-side protruding body 33 includes a protruding portion 35 protruding from the outlet-side mounting surface 34 of the flow path wall 6, and an outlet opening 36 provided by making a hole in a part of the protruding portion 35. An outlet 37 from the outlet-side enlarged space 32 is arranged so that the outlet opening 36 and the outlet 37 do not directly face each other. Reference numeral 38 denotes a flow stabilizing means provided on the downstream side of the ultrasonic wave propagation path 10 and includes a lattice-like direction regulating part 38a for adjusting a flow direction and a fluctuation suppressing part 38b formed of a mesh such as a mesh for reducing flow velocity fluctuation. ing. The outlet-side protrusion 33 is provided with a flow restrictor 30 in the same manner as the inlet-side protrusion 20. The flow restrictor 30 is formed of a grid-shaped direction restricting portion 30a for adjusting the flow direction and a mesh such as a mesh. And a fluctuation suppressing unit 30b arranged to reduce the flow velocity fluctuation.
[0035]
Next, the operation of the ultrasonic flow measuring device will be described. The flow in the forward direction is the same as that described in the first embodiment, and will not be described here. Next, in the case of a reverse flow, the water flows through the outlet 37 entered through the connection port 29 and flows into the outlet-side enlarged space 32. The flow entering the outlet-side enlarged space portion 32 is adjusted by the space whose volume has been increased, and the flow from the outlet opening 36 of the outlet-side protrusion 33 provided at a position not opposed to the outlet 37 causes the flow inside the protrusion 35. And flows into the outlet 12 provided on the downstream side of the measurement flow path 5 as a flow rectified by a sufficient approach distance of the exit side projecting body 33. Moreover, the flow passes through the flow restricting body 30 provided on the outlet-side protruding body 33, and the flow is rectified by the flow direction rectification by the lattice-shaped direction restricting part 30a and the flow velocity fluctuation by the fluctuation suppressing part 30b formed by the mesh body. It is further stabilized and flows into the outlet section 12. Although the flow entering the lead-out part 12 is bent at the bent part 14, the flow flowing into the lead-out part 12 is stable, so that the variation in the flow state is kept small even after the bending, and the flow stabilizing means is provided. The flow is further stabilized by a lattice-like direction regulating portion 38a for adjusting the flow direction at 38 and a fluctuation suppressing portion 38b formed of a mesh such as a mesh for reducing the flow velocity fluctuation, so that the flow velocity distribution is less affected by the difference on the downstream side. It is formed in the ultrasonic wave propagation path 10 of the measurement flow path 5.
[0036]
In addition, when there is a pulsation that causes a reverse flow in the flow, a similar flow velocity distribution can be reproduced in both the forward flow and the reverse flow in the forward and reverse directions, so that highly accurate measurement with reduced measurement errors can be performed. .
[0037]
Further, the inlet side projecting body 20 and the outlet side projecting body 33 and the flow restricting body 30 on the inlet side and the outlet side have the same or substantially the same shape, so that the measurement flow path can be used for flow in any direction. The flow velocity distribution of the flow flowing into the measurement flow path 5 can be approximated even if there is a pulsation that causes a reverse flow in the flow, and the flow velocity distribution of the flow flowing into the measurement flow path 5 can be approximated in both the forward and reverse flow states during the pulsation. Can be done. As described above, in the case of the forward flow, a stable flow can be supplied to the measurement flow path 5 by securing the pipe volume and the approach length by the inlet-side enlarged space portion 19 and the inlet-side protrusion 20 ; Supplies a stable flow to the measurement flow path 5 by securing the pipe volume and the approach length by the outlet-side enlarged space portion 32 and the outlet-side protruding body 33 , and in either forward or reverse flow state, the upstream or downstream pipe The measurement accuracy can be improved by supplying a stable flow to the measurement flow path 5 irrespective of the road shape, the measurement accuracy can be stabilized for the flow in both forward and reverse directions, and a highly convenient device having no installation direction can be realized. . Furthermore, even when there is a pulsation that causes a reverse flow in the flow, the measurement accuracy can be improved in both forward and reverse flow states during the pulsation.
[0038]
In addition, the flow flowing into the measurement flow path 5 can be further stabilized with respect to the flow in either the forward or reverse direction, and the measurement accuracy can be further improved. In addition, even when there is a pulsation that causes a reverse flow in the flow, the flow flowing into the measurement flow path 5 can be further stabilized and the measurement accuracy can be improved in both the forward and reverse flow states during the pulsation.
[0039]
Further, the flow flowing into the measurement flow path 5 is further stabilized for the flow in either the forward or reverse direction, and the flow velocity distribution in the measurement flow path 5 is made substantially the same. Alignment can further improve measurement accuracy. Furthermore, even when there is a pulsation that causes a reverse flow in the flow, the flow flowing into the measurement flow path 5 can be further stabilized and the measurement accuracy can be improved in both the forward and reverse flow states during the pulsation.
[0040]
Further, by arranging the bent portions 13 and 14 , the size of the apparatus can be further reduced, and the measurement flow path 5 is formed by the entrance-side or exit-side enlarged spaces 19 and 32 and the entrance-side or exit-side protrusions 20 and 33. The measurement accuracy can be improved by increasing the stability of the flow to the air.
[0041]
(Example 3)
Third Embodiment FIG. 3 is a cross-sectional view of an ultrasonic flow measurement device according to a third embodiment of the present invention. 3, the same members and the same functions as those of the embodiment of FIGS. 1 and 2 are denoted by the same reference numerals, detailed description is omitted, and different points will be mainly described.
[0042]
Reference numeral 39 denotes an inflow direction changing means for changing the flow direction of the fluid flowing into the inlet opening 23 or the outlet opening 36 to flow the fluid. The inflow direction changing means 39 covers the inlet opening 23 or the outlet opening 36. Has been installed. For this reason, even if the inlet opening 23 and the inflow port 24 are provided opposite to each other as shown in the figure, the flow out of the inflow port 24 by the inflow direction changing means 39 can be prevented from directly flowing into the inlet opening 23. In addition, the effect of stabilizing the flow due to the enlarged volume of the inlet-side enlarged space 19 can be exerted to maintain the measurement accuracy by stabilizing the flow in the measurement flow path 5. Further, since one of the inlets 24 can be designed irrespective of the position of the inlet opening 23, the degree of freedom in design is increased, and the size or cost can be reduced.
[0043]
Further, by arranging the inflow direction changing means 39 also in the outlet opening 36 of the outlet side protruding body 33 in the case of the backward flow, the same effect as in the case of the forward flow can be exerted in the backward flow, and It is possible to reduce the size or cost of a device with high measurement accuracy that can cope with bidirectional flow.
[0044]
In this way, even when the position of the inlet 24 to the inlet-side enlarged space 19 is different, a stable flow is given to the inlet opening 23 and supplied to the measurement flow path 5 to improve the measurement accuracy. Further, the degree of freedom in setting the position of the inflow port 24 to the inlet-side enlarged space 19 can be improved, and the apparatus can be reduced in size or can be designed to be easily manufactured, so that the cost can be reduced.
[0045]
In addition, a more stable flow can be supplied to the flow in both the forward and reverse directions by the measurement flow path 5, and the measurement accuracy can be improved.
[0046]
【The invention's effect】
As is clear from the above description, according to the ultrasonic flow measurement device of the present invention, it is possible to generate a stable flow velocity distribution in the measurement flow path regardless of the shape of the inflow conduit to the measurement flow path, and to improve the measurement accuracy. Can be.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an ultrasonic flow measuring device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of an ultrasonic flow measuring device according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view of an ultrasonic flow measuring device. FIG. 4 is a configuration diagram of a conventional ultrasonic flow measuring device.
5 Measurement flow path 7, 8 Ultrasonic transceiver 11 Introducing section 12 Outgoing section 13, 14 Bending section 16 Flow rate calculating means 19 Entrance-side enlarged space section 20 Inlet-side projecting bodies 22, 35 Projection section 32 Exit-side enlarged space section 33 Exit Side protrusion 39 Inflow direction changing means

Claims (9)

A measurement flow path through which a fluid to be measured flows, an introduction section and an output section provided on the upstream and downstream sides of the measurement flow path, and at least a pair of ultrasonic transceivers provided so that ultrasonic waves propagate through the measurement flow path An entrance-side enlarged space provided on the upstream side of the introduction portion, an entrance-side projection provided with an entrance opening in a projection connected to the introduction portion and projected to the entrance-side enlarged space, An ultrasonic flow rate measuring device comprising: a flow rate calculating means for transmitting and receiving an ultrasonic wave between ultrasonic transmitter / receivers and calculating a flow rate based on the transmitted / received signal. A measurement flow path through which a fluid to be measured flows, an introduction section and an output section provided on the upstream and downstream sides of the measurement flow path, and at least a pair of ultrasonic transceivers provided so that ultrasonic waves propagate through the measurement flow path And an entrance-side enlarged space provided on the upstream side of the introduction section, an exit-side enlarged space provided on the downstream side of the lead-out section, and connected to the introduction section and projected to the entrance-side enlarged space. An inlet-side protrusion provided with an inlet opening in the protrusion; an outlet-side protrusion provided with an outlet opening in a protrusion connected to the outlet and protruding into the outlet-side enlarged space; An ultrasonic flow rate measuring device comprising: a flow rate calculating means for transmitting and receiving ultrasonic waves between instruments and calculating a flow rate based on the transmitted and received signals. The ultrasonic flow rate measuring device according to any one of claims 1 to 2, wherein an inlet opening is provided with an inflow direction changing means for changing the flow direction to flow in. 3. The ultrasonic flow rate measuring device according to claim 2, wherein the inlet opening and the outlet opening are provided with an inflow direction changing means for changing the flow direction and inflowing. The ultrasonic flow rate measuring device according to any one of claims 1 to 4, wherein the inlet-side enlarged space portion is disposed immediately after the fluid control unit that controls the flow rate of the fluid to be measured. The ultrasonic flow measuring device according to any one of claims 1 to 5, wherein a flow restricting body is disposed on the inlet-side protruding body. The ultrasonic flow measuring device according to any one of claims 2 to 5, wherein a flow restrictor is disposed on the inlet-side protrusion and the outlet-side protrusion. The ultrasonic flowmeter according to claim 7, wherein the inlet-side protrusion and the outlet-side protrusion have the same or substantially the same shape as the inlet-side and outlet-side flow restrictors. The ultrasonic flow rate measuring device according to any one of claims 1 to 8, wherein a bending portion that bends the flow direction is disposed at the introduction portion and the derivation portion.

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