JP4894704B2 - Fluid flow measuring device - Google Patents

Description

  The present invention relates to an ultrasonic transducer and a fluid flow measuring device that measures the flow rate and flow velocity of a gas using ultrasonic waves generated by the ultrasonic transducer.

  Conventionally, an ultrasonic transducer in this type of flow measuring device includes a fluid inflow hole 1, a flow rate measuring unit 5, and a fluid outflow hole 2, as shown in FIG. 1 and the flow rate measurement unit 5 are provided with an inflow side rectification unit 3, and an outflow side rectification unit 4 is provided between the flow rate measurement unit 5 and the outflow hole 2. Have been configured to be symmetrical (see, for example, Patent Document 1). In this conventional flow measuring device, the flow rate of the fluid can be stably and accurately measured both when the fluid flows in the forward flow from the inflow side and when the fluid flows in the reverse flow from the outflow side. Further, the mounting direction of the flow rate measuring device is not limited. Furthermore, even when there is a pressure fluctuation in the fluid, the flow rate measuring device has no directivity and is symmetric, so that it is possible to accurately measure whether the fluid flows in a forward flow or a reverse flow.

Further, as shown in FIG. 6, the rectifying unit is composed of a chamber 6 and rectifying members 7 and 8. In this case, both when the fluid flows from the inflow side and when the fluid flows back from the outflow side, the fluid expands once in the chamber 6 and then contracts, so that the fluid is very stable in the flow path. Flowing. Further, since the flow is rectified by the rectifying member 7, the fluid flows very stably in the flow path. In particular, since it flows stably in the flow rate measuring unit 5, it is possible to accurately measure the flow rate of the fluid.
JP 2001-133307 A

  However, in the conventional configuration, the rectifying members 7 and 8 greatly affect the measurement performance of the flow rate measuring unit 5 and the shape is inevitably complicated, and the mesh 9 and the honeycomb 10 constituting the rectifying portion shown in FIG. A resin material is used for a part or all of the constituent members of the case for holding the rectifying member, and the rectifying part of the rectifying member 7 is electrically insulated, so that the rectifying part is charged by the fluid to be measured, and the rectifying part There has been a problem that dust easily adheres to the surface of the material. In the fluid flow measuring device, the ultrasonic wave is passed through the rectifying portion of the rectifying member, and the flow velocity and / or flow rate of the fluid to be measured is measured based on the ultrasonic propagation time between the ultrasonic transducers. If dust adheres to the surface of the rectifying part, even if the pressure loss of the rectifying part is not large, the ultrasonic wave is affected by dust, and the ultrasonic wave does not reach the opposing ultrasonic transducer, making measurement impossible. Was produced.

  In particular, when measuring easily charged gas that does not contain moisture, such as propane, the rectifying part is easily charged, and dust tends to adhere to the surface of the rectifying part. There was a problem of becoming impossible.

  The present invention solves the above-described conventional problems, and provides a high-performance ultrasonic transducer that is not affected by dust by providing conductive means for electrically connecting a rectifying portion that is easily charged to a flow path. An object is to provide a fluid flow measuring device used.

In order to solve the above problems, a fluid flow measuring device of the present invention is disposed between at least a pair of ultrasonic transducers disposed upstream and downstream of a flow path through which a fluid to be measured flows, and the ultrasonic transducer. A rectifying member that rectifies the flow of the fluid to be measured, the rectifying member being at least substantially parallel to the flow and disposed so as not to block the ultrasonic wave transmitted from the ultrasonic transducer, a resin case for holding the rectifying plate, it becomes an opening for passing the ultrasonic wave transmitted from ultrasonic vibrator disposed at a position above the case side of the rectifying plate, antistatic at least the rectifier plate It means provided, and wherein is obtained a configuration which is adapted to measure the flow rate and / or flow rate of the fluid to be measured based on the ultrasonic propagation time between ultrasonic sound wave transducer.

And an ultrasonic transducer disposed at least a pair on the upstream side and the downstream side of the flow path through which the fluid to be measured flows, and a rectifying member that rectifies the flow of the fluid to be measured disposed between the ultrasonic transducers, the rectifying member includes a metal rectifying plate that is disposed so as not to block the ultrasonic waves transmitted from at least substantially parallel a and the ultrasonic vibrator to the flow, and resin case for holding the rectifying plate, The opening is located on the side of the rectifying plate and allows an ultrasonic wave transmitted from the ultrasonic vibrator provided in the case to pass therethrough, and conductive means for electrically connecting the rectifying plate and the flow path is provided. And it is set as the structure which measured the flow velocity and / or flow volume of the said to-be-measured fluid based on the ultrasonic propagation time between the said ultrasonic transducer | vibrators.

  With the configuration described above, the flow control device has a flow straightening plate disposed between the ultrasonic transducers so as to be substantially parallel to the flow of rectifying the flow of the fluid to be measured and so as not to block the ultrasonic waves transmitted from the ultrasonic transducers. Since the rectifying member is provided, the flow rate of the fluid can be measured stably and accurately, and at least a rectifying plate is provided with an antistatic means, or a conducting means for electrically connecting the rectifying plate and the flow path. Therefore, the current plate can be prevented from being charged, and the flow rate and / or flow rate of the fluid to be measured can be stabilized stably over a long period of time by reducing the adhesion of foreign matter such as dust contained in the measurement fluid to the current plate. It becomes possible to measure.

  Further, a rectifying plate disposed so as to be substantially parallel to at least the flow of the rectifying member for rectifying the flow of the fluid to be measured disposed between the ultrasonic transducers and not to block the ultrasonic waves transmitted from the ultrasonic transducers. When the fluid to be measured flows in the vicinity, the friction tries to charge the rectifying plate, but at least the anti-static means provided on the rectifying plate or the electric charge of the rectifying plate electrically connects the rectifying plate and the flow path. Since the flow path is grounded by the conduction means that conducts to the current path, charging of the rectifying plate can be prevented. In particular, even when the fluid to be measured is a fluid to be measured that does not contain moisture, such as propane, which is easy to be charged, similarly, even if foreign matter such as dust contained in the fluid to be measured adheres to the current plate, Since there is no holding force, it is blown off by the flow of the fluid to be measured and does not accumulate on the surface of the current plate. Therefore, when the current plate is charged and foreign matter such as dust contained in the fluid to be measured adheres, the ultrasonic waves are affected by the dust, and the ultrasonic waves do not reach the opposing ultrasonic transducer, making measurement impossible. It becomes possible to prevent this phenomenon.

  According to the present invention, the rectifying plate that constitutes the rectifying member that rectifies the flow of the fluid to be measured disposed between the ultrasonic transducers is prevented from being charged, and the influence of foreign matters such as dust contained in the fluid to be measured is prevented. Therefore, it is possible to provide a highly reliable flow measurement device that is stable over a long period of time.

According to a first aspect of the present invention, there is provided a fluid flow measuring device comprising: at least a pair of ultrasonic transducers disposed upstream and downstream of a flow path through which a fluid to be measured flows; and a fluid to be measured disposed between the ultrasonic transducers. A rectifying member that rectifies the flow, and the rectifying member holds the rectifying plate at least substantially parallel to the flow and disposed so as not to block the ultrasonic wave transmitted from the ultrasonic transducer. A resin- made case and an opening that is located on a side of the rectifying plate and allows an ultrasonic wave transmitted from an ultrasonic transducer provided in the case to pass therethrough, and electrically connects the rectifying plate and the flow path. conducting means for conducting disposed, and wherein is obtained a configuration which is adapted to measure the flow rate and / or flow rate of the ultrasonic transducer between the ultrasonic the fluid to be measured based on the propagation time.

According to a second aspect of the present invention, there is provided a fluid flow measuring device comprising: at least a pair of ultrasonic transducers disposed upstream and downstream of a flow path through which a fluid to be measured flows; and a fluid to be measured disposed between the ultrasonic transducers. A rectifying member that rectifies the flow, wherein the rectifying member is at least substantially parallel to the flow and disposed so as not to block the ultrasonic wave transmitted from the ultrasonic transducer, and the rectifying member a resin case for holding the plate, it becomes an opening for passing the ultrasonic wave transmitted from ultrasonic vibrator disposed at a position above the case side of the rectifying plate, the flow path and the rectifying plate It provided conducting means for electrically conducting, and wherein is obtained a configuration which is adapted to measure the flow rate and / or flow rate of the ultrasonic transducer between the ultrasonic the fluid to be measured based on the propagation time.

  And a rectifying member having a rectifying plate disposed substantially in parallel with the flow of rectifying the flow of the fluid to be measured between the ultrasonic vibrators and not blocking the ultrasonic waves transmitted from the ultrasonic vibrators. Since it is arranged, the flow rate of the fluid can be measured stably and accurately, and at least a rectifying plate is provided with an antistatic means, or a conducting means for electrically connecting the rectifying plate and the flow path is provided. Therefore, charging of the current plate can be prevented, and the flow rate and / or flow rate of the fluid to be measured can be measured stably over a long period of time by reducing the adhesion of foreign matter such as dust contained in the measured fluid to the current plate. Will be able to.

  Further, a rectifying plate disposed so as to be substantially parallel to at least the flow of the rectifying member for rectifying the flow of the fluid to be measured disposed between the ultrasonic transducers and not to block the ultrasonic waves transmitted from the ultrasonic transducers. When the fluid to be measured flows in the vicinity, the friction tries to charge the rectifying plate, but at least the anti-static means provided on the rectifying plate or the electric charge of the rectifying plate electrically connects the rectifying plate and the flow path. Since the flow path is grounded by the conduction means that conducts to the current path, charging of the rectifying plate can be prevented.

  In particular, even when the fluid to be measured is a fluid to be measured that does not contain moisture, such as propane, which is easy to be charged, similarly, even if foreign matter such as dust contained in the fluid to be measured adheres to the current plate, Since there is no holding force, it is blown off by the flow of the fluid to be measured and does not accumulate on the surface of the current plate. Therefore, when the current plate is charged and foreign matter such as dust contained in the fluid to be measured adheres, the ultrasonic waves are affected by the dust, and the ultrasonic waves do not reach the opposing ultrasonic transducer, making measurement impossible. It becomes possible to prevent this phenomenon.

  The fluid flow measuring device according to the third invention is particularly provided with a conduction means for electrically conducting the flow rectifying plate and the flow path of the second invention, and a through portion penetrating the case in a part of the rectifying plate. The contact means for electrically connecting the through portion and the flow path is provided.

  And a conductive sponge for electrically connecting the flow rectifying plate and the flow path; a conductive sponge for providing a through portion that penetrates the case in a part of the flow rectifying plate; Since the contact means constituted by a spring or the like is provided, the plurality of current plates can be reliably electrically connected to the flow path with a simple configuration.

The fluid flow measuring device according to the fourth aspect of the invention is characterized in that, in particular, a conducting means for electrically conducting the rectifying plate and the flow path of the second invention is formed by passing the case through a part of the rectifying plate and rectifying the flow path and the flow path. The structure is such that the plates are in direct contact.

  And since the conduction means for electrically conducting the rectifying plate and the flow path is formed so that the case passes through a part of the rectifying plate and the flow path and the rectifying plate are in direct contact with each other, It is not necessary, the configuration is simplified, and a conduction means for electrically conducting the current plate and the flow path can be configured at low cost.

Fifth flow measuring device of the fluid of the aspect of the invention is, in particular, a conducting means for electrically connecting the rectifying plate and the flow path of the second invention, to form a resin case for holding the rectifying plate with a conductive material structure It is what.

In addition, since the conductive case for electrically connecting the rectifying plate and the flow path is made of a conductive material and the resin case that holds the rectifying plate is formed, the electric charge charged to the rectifying plate is the electric conductivity that holds the rectifying plate. Through the case made of material, it is grounded to the flow path, no other parts are required, the configuration is simple, and its electrical contact area is widened, so the flow path is more reliable Can be made electrically conductive.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
FIG. 1 is a cross-sectional view of an essential part of a fluid flow measuring device according to Embodiment 1 of the present invention, and FIG.

  In FIG. 1 and FIG. 2, an inflow side pipe 12 and an outflow side pipe 13 connected downward are provided at both ends of a horizontally arranged flow rate measurement channel 11 for measuring the flow rate of the fluid to be measured. Then, it is taken in from the inflow side pipe 12 and discharged to the outflow side pipe 13 through the flow rate measuring channel 11. The ultrasonic transducers 14 and 15 are arranged in a pair on the upstream side and the downstream side so as to sandwich the flow measurement channel 11, and a rectifying member that rectifies the flow of the fluid to be measured in the flow measurement channel 11 therebetween. 16 is arranged.

The rectifying member 16 holds a plurality of metal rectifying plates 17 disposed so as to be at least substantially parallel to the flow and not to block the ultrasonic waves transmitted from the ultrasonic transducers 14 and 15, and the rectifying plate 17. a resin case 18, located on the side of the current plate 17, and a opening 19 for passing the ultrasonic wave transmitted from the ultrasonic transducer 14, 15 provided in the casing 18.

  Further, a part of the rectifying plate 17 is provided with a penetrating portion 20 that penetrates the case 18, and contact means 21 made of a conductive material that electrically connects the penetrating portion 20 and the flow rate measuring channel 11 is disposed. ing.

In such an arrangement, the distance between the inflow-side ultrasonic transducers 14 and 15 and the outflow-side ultrasonic transducers 14 and 15 is L, ultrasonic waves are transmitted from the inflow-side ultrasonic transducers 14 and 15, and the outflow side The transmission time when receiving by the ultrasonic transducers 14 and 15 is Tud, and conversely, ultrasonic waves are transmitted from the ultrasonic transducers 14 and 15 on the outflow side, and the ultrasonic transducers 14 and 15 on the inflow side are transmitted. If the propagation time when receiving is Tdu, the sound velocity is C, and the fluid flow velocity is Vf, the following equation is established.
Tud = L / (C + Vf), Tdu = L / (C−Vf)
From this, C + Vf = L / Tud, C-Vf = L / Tdu, and as a result,
2 · Vf = (L / Tud) + (L / Tdu).
Therefore, Vf = (L / 2) [(1 / Tud) − (1 / Tdu)].

Thus, the fluid flow velocity Vf can be measured by measuring the ultrasonic propagation times Tud and Tdu. The fluid flow velocity Vf can be obtained without depending on the sound velocity C. That is, it can be seen that even if the sound velocity in the fluid changes due to the temperature change of the fluid, the measurement result is not affected. By multiplying the flow velocity Vf of the fluid by a predetermined cross-sectional area S of the flow rate measuring channel 11, the flow rate of the fluid is obtained.
Qf = as S · Vf can seek Me Rukoto.

Here, with the configuration described above, the ultrasonic waves transmitted from the ultrasonic transducers 14 and 15 are not blocked in parallel with the flow of rectifying the flow of the fluid to be measured between the ultrasonic transducers 14 and 15. Since the rectifying member 16 having a plurality of metal rectifying plates 17 arranged as described above is provided, the flow rate of the fluid can be measured stably and accurately, and the rectifying plate 17 and the flow path are connected to each other. as conducting means for electrically conducting, a portion of the current plate 17, a through portion 20 passing through the casing 18 is provided, the through portion 20 and the flow rate measuring flow path contacting means 21 for electrically connecting the to set only Therefore, the current plate 17 can be prevented from being charged, and the flow rate and / or flow rate of the fluid to be measured can be stably stabilized over a long period of time by reducing the adhesion of foreign matter such as dust contained in the measurement fluid to the current plate 17. Will be able to measure

  More specifically, the ultrasonic waves transmitted from the ultrasonic transducers 14 and 15 are substantially parallel to at least the flow of the rectifying member 16 that rectifies the flow of the fluid to be measured disposed between the ultrasonic transducers 14 and 15. When the fluid to be measured flows between the plurality of metal rectifying plates 17 arranged so as not to block the rectifying plate 17, the friction of the rectifying plate 17 is charged by the friction. Since the flow path is grounded by the contact means 21 that electrically connects the current plate 17 and the flow path, charging of the current plate 17 can be prevented.

  In particular, even when the fluid to be measured is a fluid to be measured that does not contain moisture, such as propane, which is easy to be charged, similarly, even if foreign matter such as dust contained in the fluid to be measured adheres to the rectifying plate 17, it is charged. Since there is no holding force due to the above, it is blown off by the flow of the fluid to be measured and does not collect on the surface of the rectifying plate 17. Therefore, the current plate 17 is charged and foreign matter such as dust contained in the fluid to be measured adheres, so that the ultrasonic wave is affected by the dust and the ultrasonic wave reaches the opposing ultrasonic vibrators 14 and 15. Therefore, the phenomenon that the measurement becomes impossible can be prevented.

(Embodiment 2)
FIG. 3 is a top plan view of the fluid flow measuring device according to the first embodiment of the present invention. The present embodiment is the same as that of the first embodiment except that the conduction means for electrically conducting the rectifying plate 17 and the flow rate measurement channel 11 is different from that of the first embodiment. Only the differences will be described.

  In the present embodiment, a conducting means for electrically conducting the rectifying plate 17 and the flow rate measuring channel 11 is formed by passing the case 18 through a part of the rectifying plate 22 and the flow measuring channel 11 and the rectifying plate 22. Is formed so as to be in direct contact with the penetrating portion 23.

  Then, a conducting means for electrically conducting the rectifying plate 22 and the flow rate measuring channel 11 is inserted into the case 18 through a part of the rectifying plate 22 so that the flow rate measuring channel 11 and the rectifying plate 22 are connected to the through portion 23. Since it is formed so as to be in direct contact, other components are not required, the configuration is simplified, and a conduction means for electrically conducting the rectifying plate 22 and the flow rate measurement channel 11 can be configured at low cost. .

(Embodiment 3)
FIG. 4 is a cross-sectional view of a main part of the fluid flow measuring device according to the first embodiment of the present invention. The present embodiment is the same as that of the first embodiment except that the conduction means for electrically conducting the rectifying plate 17 and the flow rate measurement channel 11 is different from that of the first embodiment. Only the differences will be described.

This embodiment, in which the conducting means for electrically connecting the rectifying plate 17 and the flow rate measuring flow path 11, to form a resin case 24 holding the rectifying plate 17 with a conductive material.

And since the resin- made case 23 which hold | maintains the rectification | straightening board 17 is formed with the electrically-conductive material as the conduction | electrical_connection means which electrically conducts the rectification | straightening board 17 and the flow-measurement flow path 11, the electric charge which charges the rectification | straightening board 17 Is grounded to the flow rate measurement flow path 11 through a case 24 formed of a conductive material that holds the rectifying plate 17, so that no other parts are required and the configuration is simplified. As a result, the contact area becomes larger, and the flow measurement channel 11 can be electrically connected more reliably.

  The conduction means for electrically conducting the rectifying plate 17 and the flow rate measuring channel 11 is intended to ground the charge to the flow rate measuring channel 11 so that the rectifying plate 17 is not charged. The same effect can be obtained even if antistatic treatment such as application of an antistatic agent is applied, and the configuration of each part may be any configuration as long as the object of the present invention is achieved. .

  As described above, the fluid flow measuring device according to the present invention prevents charging of the rectifying plate that constitutes the rectifying member that rectifies the flow of the fluid to be measured disposed between the conventional ultrasonic transducers. It is possible to prevent the influence of foreign substances such as dust contained in the measurement fluid, and to provide a more reliable flow measurement device that is stable for a long period of time. Applicable to.

Sectional drawing of the principal part in Embodiment 1 of this invention The same top surface arrangement diagram in Embodiment 1 of the present invention Top view layout diagram in Embodiment 2 of the present invention Sectional drawing of the principal part in Embodiment 3 of this invention Side view of a conventional inflow / outflow symmetrical flow meter Sectional view of rectifying unit 3 in the inflow / outflow symmetric flow meter Sectional view of our Keru rectifying member 7 in the inflow and outflow symmetric flowmeter

DESCRIPTION OF SYMBOLS 11 Flow measurement flow path 14, 15 Ultrasonic vibrator 16 Rectification member 17 Rectification plate 19 Opening 20 Through part 21 Contact means (conduction means)

Claims (5)

A rectifier comprising: at least a pair of ultrasonic transducers arranged upstream and downstream of a flow path through which the fluid to be measured flows; and a rectifying member that rectifies the flow of the fluid to be measured disposed between the ultrasonic transducers. member includes a rectifying plate that is disposed so as not to block the ultrasonic waves transmitted from at least substantially parallel a and the ultrasonic vibrator to the flow, and made of a resin case for holding the rectifying plate, the side of the rectifier plate together consist of an opening for passing the ultrasonic wave transmitted from ultrasonic vibrator disposed in said casing and located in part, provided the antistatic means at least in the rectifying plate, and ultrasonic wave propagation between the ultrasonic sound wave transducer A fluid flow measuring device that measures the flow velocity and / or flow rate of the fluid to be measured based on time. A rectifier comprising: at least a pair of ultrasonic transducers arranged upstream and downstream of a flow path through which the fluid to be measured flows; and a rectifying member that rectifies the flow of the fluid to be measured disposed between the ultrasonic transducers. member includes a rectifying plate that is disposed so as not to block the ultrasonic waves transmitted from at least substantially parallel a and the ultrasonic vibrator to the flow, and made of a resin case for holding the rectifying plate, the side of the rectifier plate together located consisting opening for passing the ultrasonic wave transmitted from ultrasonic vibrator disposed on the case part is provided with a conducting means for electrically connecting said flow path and the rectifying plate, and the ultrasonic sound wave A fluid flow measurement apparatus for measuring a flow velocity and / or a flow rate of the fluid to be measured based on an ultrasonic wave propagation time between transducers. Conducting means for electrically conducting the rectifying plate and the flow path is provided with a penetrating portion penetrating the case in a part of the rectifying plate, and contact means for electrically conducting the penetrating portion and the flow path. The fluid flow measuring device according to claim 2 provided. 3. The flow according to claim 2, wherein the conduction means for electrically conducting the rectifying plate and the flow path is formed so that the case penetrates a part of the rectifying plate and the flow path and the rectifying plate are in direct contact with each other. Body flow measurement device. The rectifying plate and conducting means for electrically connecting the flow path, the fluid flow measuring device as claimed in claim 2 formed with casing made of resin for holding the rectifying plate with a conductive material.