JP2012247299A - Ultrasonic flow rate measuring unit and gas flowmeter employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the configuration of an ultrasonic flow rate measuring unit for performing accurate flow rate measurement.SOLUTION: An ultrasonic flow rate measuring unit 10 comprises a measuring flow passage unit 15 and a sensor unit 16. The measuring flow passage unit 15 includes a measuring flow passage 26 whose cross section is rectangular and in which a fluid to be measured flows. The sensor unit 16 includes a first transceiver 42 and a second transceiver 43 covering an opening 25 provided on one surface of the measuring flow passage unit 15. Therefore, at a side of the measuring flow passage unit 15 where ultrasonic waves are propagated, a condition for measuring a flow rate can be set easily.

Description

  The present invention relates to a method for configuring an ultrasonic flow rate measuring unit that measures flow rate with ultrasonic waves, and a gas flow meter using the same.

  For example, as shown in FIG. 8, the conventional ultrasonic flowmeter 200 includes an inset type sensor unit 204 having an ultrasonic transducer 201, an ultrasonic transducer 202, and a reflective layer 203 in a flow pipe 205. It is set as the structure which measures by (for example, refer patent document 1).

Special table 2008-524616

  However, the conventional configuration has not been devised for the flow in the measurement portion of the flow pipe through which the fluid to be measured flows. On the other hand, in the case of accurate flow measurement with ultrasonic waves, various measures are taken for the fluid to be measured in the measurement area where the ultrasonic waves propagate, such as rectifying the flow or laminating in some cases. It was necessary to add.

  The present invention solves the above-mentioned conventional problem, and by dividing the ultrasonic flow rate measurement unit into a sensor unit and a measurement flow channel unit, the flow rate is measured on the measurement flow channel unit side where ultrasonic waves propagate. It is an object of the present invention to realize an ultrasonic flow measurement unit that makes it easy to set conditions for measuring the flow rate and thereby enables highly accurate flow measurement. Moreover, it aims at realization of the gas flowmeter using this.

  In order to solve the above-mentioned problem, the ultrasonic flow measurement unit of the present invention has a measurement channel unit having a measurement channel through which a fluid to be measured flows, having a rectangular cross section with an opening on one surface, A sensor unit covering the opening, a pair of ultrasonic transducers arranged at a predetermined distance in the flow direction of the sensor unit, and an ultrasonic wave transmitted from one of the pair of ultrasonic transducers A flow rate calculation unit that calculates the flow rate of the fluid to be measured from the propagation time until the signal is reflected on the reflection surface in the measurement flow channel facing the sensor unit and received by the other, As described above, since the ultrasonic flow measurement unit is divided into the sensor unit and the measurement flow path unit, it is easy to set conditions for measuring the flow rate on the measurement flow path unit side where the ultrasonic wave propagates. ,this It is obtained by allowing a more accurate flow rate measurement.

  The ultrasonic flow rate measurement unit of the present invention is configured by dividing the sensor unit and the measurement channel unit into conditions for measuring the flow rate on the measurement channel unit side where the ultrasonic wave propagates. This facilitates the flow rate measurement with high accuracy.

The perspective view which shows the ultrasonic flow measurement unit of Embodiment 1 which concerns on this invention. 1 is an exploded perspective view showing the ultrasonic flow measurement unit of FIG. AA line sectional view of FIG. BB sectional view of FIG. Sectional drawing which shows the measurement flow-path unit of Embodiment 2 which concerns on this invention. Exploded perspective view for explaining an example of assembling the flow path body of the second embodiment Sectional drawing of the gas flowmeter using the ultrasonic type flow measurement unit of Embodiment 3 which concerns on this invention Sectional view showing a conventional ultrasonic fluid measuring device

  According to a first aspect of the present invention, there is provided a measurement flow path unit having a measurement flow path having a rectangular cross section through which a fluid to be measured flows, a sensor unit that covers the opening, and a flow of the sensor unit. A pair of ultrasonic transducers arranged at a predetermined distance in the road direction, and the measurement channel unit in which an ultrasonic signal transmitted from one of the pair of ultrasonic transducers faces the sensor unit A flow rate calculation unit that calculates the flow rate of the fluid to be measured from the propagation time until it is reflected by the reflection surface in the measurement flow path and received by the other, and is an ultrasonic flow rate Since the measurement unit is divided into a sensor unit and a measurement channel unit, it is easy to set conditions for measuring the flow rate on the measurement channel unit side where the ultrasonic wave propagates. Possible It is intended.

  In a second aspect of the invention, particularly in the first aspect of the invention, the measurement flow path of the measurement flow path unit is divided into a plurality of flow paths by a plurality of partition plates parallel to the inner surface of the measurement flow path adjacent to the opening. By dividing the measurement flow path into multiple layers, the flow is rectified and the measurement accuracy using ultrasonic waves can be improved.

  The third invention is characterized in that, in the first or second invention, in particular, the sensor unit has a holding portion for holding the pair of ultrasonic transducers at a predetermined angle. Therefore, the accuracy of ultrasonic measurement can be improved by accurately setting the ultrasonic transducer.

  According to a fourth aspect of the present invention, there is provided an apparatus main body for accommodating a fluid to be measured in an airtight manner, an inlet portion of the fluid to be measured to the apparatus main body, an outlet portion of the fluid to be measured from the apparatus main body, An ultrasonic flow rate measuring unit according to any one of the above, wherein the inlet of the ultrasonic flow rate measuring unit is opened in the apparatus main body, and the outlet is connected to the outlet. Therefore, since the ultrasonic flow measurement unit is configured to be compact, it is possible to increase the degree of freedom of arrangement in the apparatus main body.

  In a fifth aspect of the invention, particularly in the fourth aspect of the invention, the inlet portion and the outlet portion are arranged on the same surface of the apparatus main body, and the ultrasonic flow rate measuring unit is located at a central portion of the apparatus main body. At the same time, the outlet portion is connected by an L-shaped connecting portion. By effectively using the internal space of the apparatus main body, a uniform flow to the ultrasonic flow measurement unit can be obtained. Inflow is possible.

  In a sixth aspect of the invention, in particular, in the fifth aspect of the invention, the ultrasonic flow rate measurement unit is configured such that the long side of the cross section of the measurement flow path or the long side of the cross section of the plurality of flow paths is the inflow direction of the measured fluid It is possible to guide the flow from the internal space of the apparatus main body to the ultrasonic flow measurement unit without difficulty.

In a seventh aspect of the invention, particularly in the sixth aspect of the invention, a shut-off valve connected to the inlet portion is built in, and the outflow direction of the fluid to be measured from the shut-off valve to the device body is measured to the inlet portion. It is characterized in that it is perpendicular to the inflow direction of the fluid, and the directivity of the inflow is relaxed, and a uniform flow can flow directly into the ultrasonic flow measurement unit. .

  Hereinafter, an ultrasonic flow rate measurement unit 10 according to a plurality of embodiments of the present invention will be described with reference to the drawings of FIGS. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a perspective view showing an ultrasonic flow measurement unit according to Embodiment 1 of the present invention. An ultrasonic flow measurement unit 10 includes a measurement flow path unit 15 and a sensor adjacent to the measurement flow path unit 15. Unit 16.

  In FIG. 2, the measurement flow path unit 15 has a flow path body 17 having a rectangular cross section continuous along the fluid flow direction.

  The flow path body 17 spans the first side wall 21 adjacent to the sensor unit 16, the second side wall 22 parallel to the first side wall 21, and the tops of the first side wall 21 and the second side wall 22. The top plate part 23 and the bottom plate part 24 spanned on the bottoms of the first side wall part 21 and the second side wall part 22 are provided.

  The first side wall portion 21 is one surface constituting the flow path body 17 and has an opening 25 in this portion.

  The first side wall portion 21, the second side wall portion 22, the top plate portion 23, and the bottom plate portion 24 are integrally formed (specifically, resin molding), and the first side wall portion 21, the second side wall portion 22, and the top plate are formed. This is a resin member that forms the measurement flow path 26 in a rectangular tube shape by the portion 23 and the bottom plate portion 24.

  FIG. 3 shows a cross section taken along line AA of FIG. 1. In FIG. 3, the first side wall portion 21 is formed with a first ultrasonic input / output portion 32 and a second ultrasonic input / output portion 33. . In addition, an ultrasonic transmission film 34 that covers the first ultrasonic input / output unit 32 and the second ultrasonic input / output unit 33 is disposed on the first side wall 21.

  The ultrasonic transmission film 34 has a function of transmitting ultrasonic waves but substantially blocking the flow of fluid. As an example of the ultrasonic transmission film 34, a mesh member that transmits ultrasonic waves is illustrated. However, the ultrasonic transmission film 34 is not limited thereto, and other members such as a punching metal member may be used.

  In addition, the inner surface of the second side wall portion 22 constituting the measurement flow path 26 also serves as an ultrasonic reflection surface 35.

  4 shows a cross section taken along the line BB of FIG. 3. As shown in FIG. 4, the flow path body 17 is formed inside the flow path body 17 (ie, the measurement flow path 26) by a plurality of partition plates 28. ) Is divided into a plurality of flat flow paths 27. The plurality of partition plates 28 are inserted and fixed in the flow channel body 17 molded with resin. When the flow path body 17 is resin-molded, it may be molded (insert molded) integrally with the first side wall portion 21 and the second side wall portion 22.

  As shown in FIGS. 2 and 3, the sensor unit 16 is provided so as to cover the opening 25 of the first side wall 21 of the flow path body 17.

As shown in FIG. 3, the sensor unit 16 includes a first ultrasonic transducer 42 (hereinafter referred to as a first transducer 42) held by the sensor holding unit 41 and a second ultrasonic transducer. Vessel 43
(Hereinafter referred to as the second transducer 43).

  The first transmitter / receiver 42 and the second transmitter / receiver 43 are arranged at a predetermined distance in the flow direction of the measurement flow path 26, and the sensor holding unit 41 includes the first transmitter / receiver 42 and the second transmitter / receiver 42. The waver 43 is formed to be held at a predetermined angle (α).

  By creating the sensor unit 16 by resin molding, the predetermined distance and the predetermined angle at which the first transducer 42 and the second transducer 43 are installed can be configured with high accuracy.

  The first transducer 42 is attached to the sensor holding portion 41 with a first sensor packing 45 and a first sensor fixing member 46.

  Similarly, the second transducer 43 is attached to the sensor holding portion 41 with a second sensor packing 47 and a second sensor fixing member 48.

  Next, an example in which the flow rate of the fluid is measured by the ultrasonic flow rate measurement unit 10 will be described with reference to FIG.

  M shown in FIG. 3 is an ultrasonic wave propagation path. Arrows P <b> 1 and P <b> 2 indicate propagation directions of ultrasonic waves propagating from the first transducer 42 to the second transducer 43. Arrows Q1 and Q2 indicate the propagation directions of the ultrasonic waves propagating from the second transducer 43 to the first transducer 42.

  Let V be the flow velocity of the fluid flowing through the measurement channel 26, C be the velocity of sound in the fluid, and θ be the angle between the direction in which the fluid flows and the direction of ultrasonic propagation until the ultrasonic wave is reflected by the reflecting surface 35. Also, let L be the effective length of the propagation path when the ultrasonic wave propagates between the first transducer 42 and the second transducer 43.

  At this time, the propagation time t1 until the ultrasonic wave emitted from the first transducer 42 reaches the second transducer 43 is expressed by the following equation.

t1 = L / (C + Vcos θ) (1)
Next, the propagation time t2 until the ultrasonic wave emitted from the second transducer 43 reaches the first transducer 42 is expressed by the following equation.

t2 = L / (C−Vcos θ) (2)
When the sound velocity C of the fluid is eliminated from the equations (1) and (2), the following equation is obtained.

V = L / (2cos θ ((1 / t1) − (1 / t2))) (3)
As can be seen from the equation (3), if L and θ are known, the flow velocity V can be obtained using the propagation times t1 and t2.

  A flow rate calculation unit (not shown) performs the above calculation together with the measurement of the propagation times t1 and t2 described above, and first obtains the flow velocity V. The flow rate Q is obtained by multiplying the flow velocity V by the cross-sectional area S of the measurement flow path 26 and the correction coefficient k.

  Thus, in the ultrasonic flow measurement unit 10 of the present invention, since the ultrasonic flow measurement unit 10 is divided into the sensor unit 16 and the measurement flow path unit 15, the measurement flow through which the ultrasonic wave propagates is configured. On the road unit 15 side, it is possible to easily set conditions for measuring the flow rate.

  In the present embodiment, the flow channel 26 can be divided into a plurality of parts, the flow can be rectified, and the ultrasonic propagation time can be measured in a stable state, so that highly accurate flow measurement can be performed. It is.

  In addition, since the ultrasonic flow rate measurement unit 10 is configured only by combining the sensor unit 16 and the measurement flow path unit 15 as described above, a compact configuration can be realized.

(Embodiment 2)
Next, the second embodiment will be described with reference to FIGS.

  In the second embodiment, the same or similar members as those of the measurement flow path unit 15 of the first embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 5 is a sectional view corresponding to FIG. 3 of the first embodiment. Since the sensor unit is the same, it is omitted. As shown in FIG. 5, the measurement flow path unit 70 according to the second embodiment of the present invention has a flow path body 71 instead of the flow path body 17.

  In the measurement flow path unit 70 of the second embodiment shown here, the flow path main body 71 includes a first side wall portion 21, a second side wall portion 22, a top plate portion 23, and a bottom plate portion 24, as shown in FIG. It consists of individual members.

  When the first side wall part 21, the second side wall part 22, the top plate part 23 and the bottom plate part 24 are assembled, the housing recess 72 (from the back surface 21 a side of the first side wall part 21 (that is, the measurement channel 26 side). The ultrasonic permeable membrane 34 is assembled to (see FIG. 5).

  In addition, when the first side wall portion 21, the second side wall portion 22, the top plate portion 23, and the bottom plate portion 24 are assembled, a plurality of partition plates 28 are assembled.

  Thus, the measurement flow path unit 70 of Embodiment 2 can be assembled | attached by comprising the 1st side wall part 21, the 2nd side wall part 22, the top-plate part 23, and the baseplate part 24 with each separate member. .

  Here, as for the flow-path main body 71, the 1st side wall part 21, the 2nd side wall part 22, the top-plate part 23, and the baseplate part 24 are each formed with the members made from resin.

  According to the measurement flow path unit 70 of the second embodiment, the ultrasonic transmission film 34 can be installed without having a step on the inner surface of the measurement flow path 26.

(Embodiment 3)
Next, Embodiment 3 will be described with reference to FIG.

  FIG. 7 is a cross-sectional view of a gas flow meter using an ultrasonic flow measurement unit.

  The gas flow meter 140 according to the third embodiment of the present invention shown in FIG. 7 has an ultrasonic flow measurement unit 142 disposed in a box-shaped device main body 141 that contains a fluid to be measured in an airtight manner, and is fixed by screws or the like. Has been. In this case, the ultrasonic flow rate measuring unit 142 is disposed at a substantially central portion of the apparatus main body 141.

  The ultrasonic flow measurement unit 142 is basically the same as the ultrasonic flow measurement unit shown in the first embodiment.

  The apparatus main body 141 has an inlet pipe 143 (inlet part) and an outlet pipe 144 (outlet part) communicating with each other inside and outside. The inlet pipe 143 and the outlet pipe 144 are arranged on the same plane.

  The inlet pipe 143 is opened inside the apparatus main body 141 via a shut-off valve 145. The outlet pipe 144 is connected to the ultrasonic flow rate measuring unit 142 inside the apparatus main body 141 through an L-shaped connecting portion 146.

  In the gas flow meter 140, the fluid 60 that has flowed into the apparatus main body 141 through the inlet pipe 143 enters from the inlet of the ultrasonic flow measurement unit 142, and then is discharged to the outside of the apparatus main body 141 through the outlet pipe 144. It becomes the composition which is done.

  According to the third embodiment, since the ultrasonic flow rate measuring unit 142 arranged inside is compactly configured, the degree of freedom in arrangement is large. Further, since the inlet of the ultrasonic flow rate measuring unit 142 is open to a wide space of the apparatus main body 141, the flow to the ultrasonic flow rate measuring unit 142 can be uniformly guided.

  Further, by arranging the long side of the cross section of the measurement flow path 26 or the long side of the cross section of the plurality of flow paths to be parallel to the inflow direction of the fluid to be measured, The flow can be guided to the ultrasonic flow rate measuring unit 142 without difficulty.

  In addition, since the outflow of the flow from the shutoff valve 145 is configured to be perpendicular to the inflow direction, the direction of the inflow is relaxed, and a uniform flow can flow directly into the ultrasonic flow measurement unit 142. Is.

  The ultrasonic flow rate measurement unit 10 and the measurement flow path units 15 and 70 according to the present invention are not limited to the first embodiment and the second embodiment described above, and can be changed or improved as appropriate. is there.

  For example, in the first embodiment and the second embodiment, the example in which the flow path main bodies 17 and 71 are formed of resin members has been described. However, the present invention is not limited to this, and may be formed of metal members. is there.

  In all of the embodiments, the ultrasonic transmission film 34 is disposed between the measurement flow path units 15 and 70 and the sensor unit 16, but may be omitted if not required in terms of performance.

  Further, the ultrasonic flow rate measurement unit 10, the measurement flow path units 15 and 70, the sensor unit 16, the flow path main bodies 17 and 71, the first side wall 21, and the second used in the first to third embodiments. Side wall part 22, top plate part 23, bottom plate part 24, measurement channel 26, flat channel 27, partition plate 28, ultrasonic input / output unit 31, first ultrasonic input / output unit 32, second ultrasonic input / output unit 33, reflection The shapes and configurations of the surface 35, the ultrasonic transmission film 34, the first transducer 42, the second transducer 43, and the like are not limited to those illustrated, and can be changed as appropriate.

  The ultrasonic flow measurement unit can be applied to various gas meters.

DESCRIPTION OF SYMBOLS 10 Ultrasonic flow measurement unit 15,70 Measurement flow path unit 16 Sensor unit 17,71 Flow path main body 25 Opening part 26 Measurement flow path 28 Partition plate 35 Reflecting surface 41 Sensor holding part 42 1st transmitter / receiver (ultrasonic transmission / reception) Waver)
43 Second transducer (ultrasonic transducer)
140 Gas Flowmeter 141 Device Main Body 142 Ultrasonic Flow Measurement Unit 143 Inlet Pipe (Inlet)
144 Exit pipe (exit part)
145 Shutoff valve 146 Connection

Claims (7)

A measurement channel unit having an opening on one surface and a measurement channel having a rectangular cross section through which the fluid to be measured flows;
A sensor unit covering the opening;
A pair of ultrasonic transducers arranged at a predetermined distance in the flow path direction of the sensor unit, and an ultrasonic signal transmitted from one of the pair of ultrasonic transducers face the sensor unit. A flow rate calculation unit that calculates the flow rate of the fluid to be measured from the propagation time until it is reflected by the reflecting surface in the measurement flow channel of the measurement flow channel unit and received by the other;
Ultrasonic flow measurement unit consisting of 2. The ultrasonic type according to claim 1, wherein the measurement channel of the measurement channel unit is partitioned into a plurality of channels by a plurality of partition plates parallel to the inner surface of the measurement channel adjacent to the opening. Flow measurement unit. The ultrasonic flow rate measuring unit according to claim 1, wherein the sensor unit has a holding unit for holding the pair of ultrasonic transducers at a predetermined angle. An apparatus main body for accommodating a fluid to be measured in an airtight manner;
An inlet portion of the fluid to be measured into the apparatus body;
An outlet portion of the fluid to be measured from the apparatus main body,
The ultrasonic flow measurement unit according to any one of claims 1 to 3,
Consists of
A gas flowmeter in which an inlet of the ultrasonic flow measurement unit is opened in the apparatus main body, and an outlet is connected to the outlet. The inlet portion and the outlet portion are arranged on the same surface of the apparatus main body,
5. The gas flow meter according to claim 4, wherein the ultrasonic flow rate measuring unit is located at a central portion of the apparatus main body and is connected to the outlet portion by an L-shaped connecting portion. The ultrasonic flow rate measuring unit is arranged such that a long side of a cross section of the measurement flow path or a long side of a cross section of a plurality of flow paths is parallel to an inflow direction of a fluid to be measured. Gas flow meter. A shut-off valve connected to the inlet portion is built in, and the outflow direction of the fluid to be measured from the shut-off valve to the apparatus main body is a direction perpendicular to the inflow direction of the fluid to be measured to the inlet portion. 6. The gas flow meter according to 6.

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