JPH0552609A - Fluidic flow meter - Google Patents

Abstract

PURPOSE:To enable use of a flow meter as a home gas meter, etc., by making it in simple construction in which bypass flow path, selector valve, etc., are not structured and increasing measurement flow range without increasing pressure loss. CONSTITUTION:Multiple measurement parts A, B, and C, provided with flow path restriction parts 4, jet nozzles 5, flow path expansion parts 6, guide pendulums 7, and end blocks 9, are positioned in parallel to flowing direction of a fluid induced from a common flow-in pipe 1. By this, even if the opening width of the jet nozzles 5A, 5B, and 5C at the measurement parts A, B, and C is so formed as to be capable of vibrating sufficiently with low flow, the opening width of the jet nozzles which affects pressure loss becomes the sum of the opening widths of the jet nozzles 5A, 5B, and 5C. Thus the measurement range can be increased from low flow to large one without increasing pressure loss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidic flow meter used for measuring the flow rate of gas or liquid.

[0002]

2. Description of the Related Art A fluidic flowmeter utilizing fluidic oscillation, which has been developed as an alternative to a conventional membrane gas meter, is small in size and has no moving parts. Research and improvement are being carried out in various fields. Further, it is desired that the conventional gas flow meter requires a rising area for mounting and is small in view of urban aesthetics and does not matter in directionality in mounting. From this point of view, there is a demand for a small and high-performance fluidic flowmeter that takes advantage of its characteristics.

As described in general textbooks, the fluidic flowmeter pays attention to the fact that the flow acts to control itself, thereby causing vibration, and that the frequency is proportional to the flow rate. It was used. Such a fluidic flowmeter is disclosed in, for example, Japanese Patent Laid-Open No. 63-13921.
Although disclosed in Japanese Patent Laid-Open No. 3 and Japanese Patent Laid-Open No. 63-139214, its basic structure and operation will be described with reference to FIG.

A set ring space 3, a flow path contracting section 4, a jet nozzle 5, and a flow path expanding section 6 are provided in this order on the path connecting the inflow tube 1 and the exhaust tube 2, and the flow path expanding section 6 is guided. The pendulum 7, side blocks 8 and end blocks 9 are provided. Here, such a fluidic flowmeter has a line-symmetrical shape with respect to a straight line connecting the jet nozzle 5 and the exciter 7. End block 9
Has walls 9a, 9b extending toward the upstream side of the flow path so as to cover the side block 8 on both sides. Also,
Behind this end block 9 is a discharge space 10.

First, the tubular flow from the upstream side of the flow path is rectified into a two-dimensional flow in the set ring space 3 and further rectified by the flow path contracting section 4 to smoothly flow toward the jet nozzle 5. Then, the jet flow rectified by the jet nozzle 5 is divided into right and left by hitting the exciter 7, but in the space of the flow path expanding portion 6 up to the end block 9, when the flow exceeds a certain flow rate, the exciter 7 is discharged. Due to the instability of the vortex behind it, a left or right biased flow is formed. Therefore, the flow that hits the end block 9
Along the front of the end block 9 and side blocks 8
Along the circumference, it reaches the outlet of the jet nozzle 5 and hits the jet stream at right angles. Therefore, the direction of the jet flow is biased in the direction opposite to the initial drift by the flow returning from the side. This causes the same thing to happen again on the opposite side, with the result that the flow leaving the jet nozzle 5 changes direction in a regular and alternating manner. The frequency of this regular directional vibration increases linearly with increasing flow rate.

[0006]

However, in the case of such a fluidic flowmeter, although the frequency of vibration is almost proportional to the flow rate, its linearly changing range is 150 to 3000 per liter / hour. For example, it is not within the range that can be used as a home gas meter, and the pressure loss is not at a level that can be used as a home gas meter at the maximum measurement flow rate.

That is, if the flow rate is the same, the velocity of the fluid flowing from the jet nozzle 5 increases as the opening width of the jet nozzle 5 becomes narrower. Although it suffices to narrow the opening width, when the flow rate is large, the pressure loss increases and the gas meter cannot be used. On the contrary, on the contrary,
When the opening width of the jet nozzle 5 is widened, the pressure loss is reduced, but at a low flow rate, it does not vibrate.

From the above, for example, JP-A-61-161
No. 77717 discloses that a jet nozzle is formed with a main jet port and sub-spray ports on both sides thereof, and the sub-spray port side is opened and closed according to the flow rate to substantially change the opening width of the jet nozzle, thereby reducing the flow rate. Is shown to be able to cope with a large flow rate.

Further, Japanese Patent Laid-Open No. 61-223517,
JP-A-62-21019, JP-A-62-1021
According to Japanese Patent Laid-Open No. 19 and Japanese Patent Laid-Open No. 62-175619, Japanese Patent Laid-Open No. 63-140916, etc., it is formed by elements such as a flow passage reducing portion, a jet nozzle, a flow passage expanding portion, a pendulum, and an end block. It is shown that a plurality of measuring units are provided, the opening width of the jet nozzle is different in each measuring unit, and these measuring units are arranged in series in the flow direction. Thus, when the flow rate is low, the measurement section having a jet nozzle with a narrow opening width is used for measurement, and when the flow rate is high, the measurement section having a jet nozzle with a wide opening width is used for measurement.

However, in the case of such a variable structure of the opening width of the jet nozzle and a structure in which a plurality of measuring parts are arranged in series,
The structure is complicated, for example, a switching valve for low flow rate and high flow rate and a bypass flow path are required.

[0011]

According to a first aspect of the present invention, a flow restricting portion for rectifying, a jet nozzle, and a flow passage expanding portion are sequentially provided in the flow direction, and the jet nozzle in the flow passage expanding portion is opposed to the jet nozzle. A position-providing pendulum is provided, and a measuring part is formed by providing an end block for forming a return flow path at a position behind the pendulum in the flow path expansion part and reaching the discharge pipe. The individual measuring units were arranged in parallel with the flow direction of the fluid introduced from the common inflow pipe.

In this case, according to the second aspect of the invention, each measuring section is formed in an asymmetrical shape with respect to the straight line connecting the jet nozzle and the exciter.

Further, in the invention according to the third aspect, the opening width of the jet nozzle of each measuring portion is made different in the order of widening as the distance from the inflow pipe increases.

On the other hand, in the invention according to claim 4, a flow reducing portion for rectification, a jet nozzle, and a flow passage expanding portion are sequentially provided in the flow direction, and a position in the flow passage expanding portion up to the discharge pipe is provided. An end block for forming a return flow passage is provided in the plurality of divided flow passage enlarged portions in a direction parallel to the flow direction from the jet nozzle so that the divided flow passage enlarged portions are formed in symmetry with each other. A plurality of exciters that cause a drift is provided at symmetrical positions to form a plurality of measurement units in parallel.

[0015]

According to the invention described in claim 1, when the opening width of the jet nozzle of each measuring portion is set to a width that can sufficiently vibrate even at a low flow rate, the pressure loss is high in each jet nozzle with respect to a large flow rate. However, since these jet nozzles are arranged in parallel to the flow direction, the opening width of the jet nozzle that affects the pressure loss is the sum of the opening widths of these jet nozzles, so the pressure loss is sufficient. It gets lower. Therefore, the measured flow rate range can be expanded to a state where it can be used as a household gas meter or the like without increasing pressure loss. As a structure therefor, a structure in which a plurality of measuring units are arranged in parallel is sufficient, and it is a simple structure that does not require a bypass flow passage, a switching valve structure, or the like.

In this case, according to the second aspect of the invention, since each measuring portion is formed in an asymmetrical shape with respect to the straight line connecting the jet nozzle and the exciter, one of the measuring parts should be smaller than the straight line. By doing so, space saving can be achieved even in the multi-stage structure.

According to the third aspect of the invention, the opening widths of the jet nozzles of the respective measuring units are made different in the order of increasing the distance from the common inflow pipe. Therefore, the opening width of the jet nozzle closest to the inflow pipe is different. By making N.sub.2 narrower, it is possible to vibrate to a lower flow rate for measurement, the measurement flow rate range can be broadened, and the measurement accuracy can be improved.

On the other hand, according to the fourth aspect of the invention, a plurality of measurement points can be taken at symmetrical positions in a direction parallel to the common jet nozzle in a direction parallel to the flow direction, and each measurement is performed under the same flow condition. Since the section shows individual measurement values according to the magnitude of the flow rate, the measurement error can be corrected by the arithmetic processing based on these plural measurement results, and the measurement accuracy can be improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. The same parts as those shown in FIG. 7 are designated by the same reference numerals. First, FIG. 2 shows a premise structure of the fluidic flow meter of the present embodiment. In a general fluidic flowmeter as shown in FIG. 7, as a result of experimentally examining basic components such as the jet nozzle 5, the pendulum 7, and the end block 9 as to the principle of vibration,
It was found that the flow-rectifying flow path reducing section 4, the jet nozzle 5, and the pendulum 7 that is the target of the flow play a large role, and further, the end block 9 plays a role of a return path. Therefore, the premise structure is similar to the structure of the general fluidic flowmeter shown in FIG. 7 in order to utilize the characteristics of the fluidic flowmeter, but the side block 8 is omitted. There is. Here, the tips of the walls 9a and 9b on both sides of the end block 9 toward the upstream side of the flow path of the present embodiment are located at a vertical line Y position with respect to the straight line X on the jet nozzle 5 facing surface side (left side in the drawing) of the pendulum 7. Has been extended to.

In this embodiment, however, the structure consisting of the flow path contracting section 4, the jet nozzle 5, the flow path expanding section 6, the pendulum 7, and the end block 9 as shown in FIG. As shown in FIG. 1, three measuring parts A, B, C were arranged in parallel in the flow direction (left and right direction in the drawing) in the pipe member 12 from the inflow pipe 1 to the exhaust pipe 2. It is a thing. The settling space 3 and the discharge space 10 are shared. More specifically, the measurement unit A is arranged on the same line as the inflow pipe 1, and the measurement units B and C are arranged so as to be separated from the inflow pipe 1 in this order. Here, each measuring unit A, B, C
The opening widths of the jet nozzles 5A, 5B, 5C are narrower so that they can vibrate sufficiently even at a low flow rate.

In such a structure, the flow of the fluid guided from the inflow pipe 1 passes through the jet nozzle 5A of the measuring section A as it is at a low flow rate and vibrates according to the principle explained in FIG. When the flow rate is gradually increased, the flow of the fluid passes through not only the jet nozzle 5A of the measuring section A but also the jet nozzle 5B due to the increase of the energy of the fluid, and the measuring section B also vibrates. When the flow rate is further increased, the jet nozzle 5C also passes, and the measuring section C also vibrates.

Here, for a large flow rate, the pressure loss becomes too high with the opening width of each jet nozzle 5A, 5B, 5C, but these jet nozzles 5A, 5B, 5C are too large.
Are arranged in parallel to the flow direction, the opening width of the jet nozzle that influences the pressure loss is the sum of the opening widths of these jet nozzles 5A, 5B, 5C, and the pressure loss is sufficiently low. Therefore, it is possible to measure from a low flow rate to a large flow rate without increasing the pressure loss with respect to the large flow rate.

Further, these jet nozzles 5A, 5
As for the opening widths of B and 5C, it is only necessary that the total has a predetermined value, and it is not necessary to make each of them uniform widths.
As shown in FIG. 5, the opening widths of the jet nozzles 5A, 5B, 5C may be varied so that the opening width becomes wider as the distance from the inflow pipe 1 increases. In this way, by making the opening width different and narrowing the opening width of the jet nozzle 5A closest to the inflow pipe 1, it is possible to vibrate to a lower flow rate for measurement. In this case, the jet nozzles 5A, 5B, 5C
Jet nozzles 5A, 5B, 5 depending on the width of the opening of the
Pendulum 7A, 7B, 7C for C, end block 9
It is better to make the distances A, 9B, 9C different.

In this embodiment, the number of measuring units is three, but the number of measuring units is not limited to three, and an appropriate number may be arranged in parallel.
Further, the structure of the measuring unit is not limited to the simplified structure in which the side block 8 is omitted as shown in FIG. 2, but may be the general structure as shown in FIG.

Next, a second embodiment of the present invention will be described with reference to FIGS. First, the premise structure of the present embodiment will be described with reference to FIG. Here, in addition to the configuration of FIG. 2, when considered for the purpose of reducing the entire size, the space of the flow path expanding portion 6 is symmetric with respect to a straight line X connecting the center of the jet nozzle 5 and the center of the exciter 7. Since it has been found that the shape need not be formed, it is formed asymmetrically with respect to the straight line X. In comparison with FIG. 2, the jet nozzle 5
The right side (the lower side of the straight line X in the figure) viewed from the side is asymmetrical as it is shortened. More specifically, in the illustrated example, the space is suppressed to about 2/3 in order to obtain the same characteristics as the conventional one. Further, in the end block 9, the tip end of the wall 9a is largely extended toward the upstream side in correspondence with the asymmetrical shape, while the wall 9b side is slightly extended. In the illustrated example, the left side (upper side of the straight line X in the figure) viewed from the jet nozzle 5 is asymmetrical, but the operation is the same regardless of whether the left side or the right side is increased.

According to such an asymmetrical fluidic flow meter, by reducing one side of the flow path of the vibration due to the feedback, the vibration is surely promoted even at a small flow rate, so that the flow rate range from the small flow rate is small. It will spread to a large flow rate.

In this embodiment, however, one such asymmetric fluidic flowmeter structure is used as one measuring section, and as shown in FIG. 5, for example, two measuring sections D and E are arranged in the flow direction. Are arranged in parallel. here,
As in the case of FIG. 3, the jet nozzle 5E has a wider opening width than the jet nozzle 5D.

According to this embodiment, similar to the above embodiment,
It is possible to measure from a low flow rate to a large flow rate without increasing the pressure loss for a large flow rate, and it is possible to save the entire space.

Further, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, a large flow passage expanding portion 13 is formed in the flow direction following the inflow pipe 1, the set ring space 3, the flow passage reducing portion 4, and the jet nozzle 5, and the discharge pipe 2 is formed in the flow passage expanding portion 13. A long end block 9 is provided in front of. The end block 9 is an inner wall 13a of the flow path enlarging portion 13 formed by the pipe member 12 on the jet nozzle 5 side.
Along with the flow direction from the jet nozzle 5 to the discharge pipe 2, a plurality of divided flow channel expanding portions 13 are arranged in parallel with each other.
A, 13B, 13C, and 13D (8 pieces in total) are formed symmetrically in a communicating state. In addition, a plurality of exciters 15 for causing a nonuniform flow are provided in these divided flow channel enlarged portions. More specifically, an exciter 15A arranged at a position facing the jet nozzle 5 (that is, corresponding to the ordinary exciter 7), and an exciter 15AB arranged between the divided flow channel expanding portions 13A and 13B, Divided channel expansion part 13
A total of seven exciters 15BC arranged between B and 13C and a exciter 15CD arranged between the divided flow path expanding portions 13C and 13D are provided. Here, centering around the pendulum 15A, the pendulums 15AB, 15BC, and 15CD are staggered in a staggered arrangement.

In such a structure, the flow of the fluid flowing into the jet nozzle 5 from the flow path reducing portion 4 hits the exciter 15A located on the center line and is biased to the left and right (up and down in the figure) due to instability. Therefore, the divided flow channel expanding portion 13A
The flow passing through the end block 9 and along the inner wall of the end block 9 hits the next exciter 15AB, so that the flow is also biased to the left and right. Therefore, the flow is
It is divided into one that strikes the jet flow from the jet nozzle 5 along a at a right angle, and one that flows along the inner wall 13a into the next divided flow channel enlarged portion 13B. The former flow regularly and alternately changes the flow from the jet nozzle 5 to the left and right. The latter flow is based on the divided flow channel expansion section 13B.
By hitting the next exciter 15BC along the inner wall 13a, it is also biased to the left and right. For this reason, the flow is divided into one that goes along the inner wall of the end block 9 toward the exciter 15AB side again, and one that goes into the next divided flow channel expanding portion 15C. As in the first case, the flow to the pendulum 15AB changes the flow from the divided flow channel expanding section 13A alternately and horizontally, and the flow to the divided flow channel expanding section 15C proceeds to the next pendulum 15CD. It will be similarly biased. The flow is similarly controlled in the fourth-stage exciter 15CD, and the flow to the final divided flow channel expanding portion 13D passes through the discharge space 10 and is discharged from the discharge pipe 2. That is, it has a structure in which three measuring units A, B, and C are arranged on one side and six measuring units are arranged on both sides corresponding to the divided flow channel expanding units 13A to 13C.

Here, a sensor such as a pressure sensor for detecting a change in flow rate is arranged at symmetrical positions in each of the measuring sections A to C,
The value of each step is sensed in pairs on the left and right. At this time, the sensor output in each of the measuring units A to C shows an individual value depending on the magnitude of the flow rate, but the measured value is large or small regardless of whether the flow rate is large, medium, or small. The relationships are in the order of A ≧ B ≧ C. Therefore, for the measured value of each stage, the flowing fluid (water,
The measurement error can be improved by correcting / converting according to (gas, air, etc.). That is, the jet nozzle 5
The fluid flowing in from is measured symmetrically under the same conditions at three locations on one side and six locations on both sides according to the magnitude of the flow rate, so it is possible to correct and improve the measurement accuracy. Becomes

[0032]

Since the present invention is configured as described above, according to the first aspect of the invention, a plurality of flow path reducing parts, jet nozzles, flow path expanding parts, pendulums and end blocks are provided. Since the measuring parts of are arranged in parallel to the flow direction of the fluid introduced from the common inflow pipe, the opening width of the jet nozzle of each measuring part is formed so that it can vibrate sufficiently even at a low flow rate. If this is the case, the opening width of the jet nozzle that affects the pressure loss is the sum of the opening widths of these jet nozzles, so the measurement range can be expanded from low flow rates to high flow rates without increasing pressure loss. It can be used as a gas meter for use, and a structure for that purpose can be a parallel arrangement structure of a plurality of measuring units, and it is a simple structure that does not require a bypass flow passage, a switching valve structure, or the like.

In this case, according to the second aspect of the present invention, each measuring portion is formed in an asymmetrical shape with respect to the straight line connecting the jet nozzle and the exciter, so one of the measuring parts should be smaller than the straight line. By doing so, more space can be saved even in a multi-stage structure, and vibration can be surely promoted by the asymmetrical shape even in individual measuring parts, so that the measuring range can be expanded and the overall performance It can be improved.

Further, according to the third aspect of the invention, the opening width of the jet nozzle of each measuring section is made different in the order of widening as it goes away from the common inflow pipe. The opening width of the nozzle can be made narrower, the measurement flow rate range can be further widened, and the measurement accuracy can be improved.

On the other hand, according to the fourth aspect of the invention, a plurality of measurement points can be taken at symmetrical positions in a direction parallel to the common jet nozzle in the direction parallel to the flow direction, and the flow rate can be changed under the same flow condition. Since a plurality of measurement results depending on the size can be obtained, the measurement error can be corrected by the arithmetic processing, and thus the measurement accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a horizontal sectional view showing a first embodiment of the present invention.

FIG. 2 is a horizontal cross-sectional view showing the premise structure thereof.

FIG. 3 is a horizontal sectional view showing a modified example.

FIG. 4 is a horizontal cross-sectional view showing a prerequisite structure of the second embodiment of the present invention.

FIG. 5 is a horizontal sectional view showing the gist thereof.

FIG. 6 is a horizontal sectional view showing a third embodiment of the present invention.

FIG. 7 is a horizontal sectional view showing a general fluidic flow meter structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inflow pipe 2 Exhaust pipe 4 Flow path reduction part 5 Jet nozzle 6 Flow path expansion part 7 Pendulum 9 End block 13 Flow path expansion part 13A-13D Split flow path expansion part 15A-15CD Pendulum AE measurement part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuko Oshima, Inc. Yuko Oshima, Tokyo 1-3-6 Nakamagome, Ricoh Co., Ltd. (72) Inventor, Yoshio Watanabe 1-3-6 Nakamagome, Ota-ku, Tokyo Stocks In Ricoh Company (72) Kenji Okada 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (72) Inventor Masafumi Kadaga 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (72) Inventor Toshiyuki Takamiya 6-16-10 Minamioi, Shinagawa-ku, Tokyo Ricoh Seiki Co., Ltd.

Claims (4)

[Claims] 1. A flow reducing portion for rectifying, a jet nozzle, and a flow passage expanding portion are sequentially provided in a flow direction, and a pendulum for causing a drift is provided at a position facing the jet nozzle in the flow passage expanding portion. An end block for forming the return flow passage is provided at a position behind the exciter in the flow passage enlarged portion up to the discharge pipe to form a measurement portion, and a plurality of measurement portions are introduced from a common inflow pipe. A fluidic flow meter, wherein the fluidic flow meter is arranged in parallel with the flowing direction of the fluid. 2. The fluidic flow meter according to claim 1, wherein each of the measuring parts is formed in an asymmetrical shape with respect to a straight line connecting the jet nozzle and the exciter. 3. The opening width of the jet nozzle of each measuring unit is
3. The fluidic flow meter according to claim 1, wherein the fluidic flow meter has a different order in which it spreads away from the inflow pipe. 4. An end for forming a return flow passage is provided at a position in the flow passage expansion portion up to the discharge pipe, in which a flow reduction portion for rectification, a jet nozzle, and a flow passage expansion portion are sequentially provided in the flow direction. A plurality of exciters that are provided with blocks to form a plurality of divided flow passage enlarged portions in a direction parallel to the flow direction from the jet nozzle so as to be symmetrical and to cause a drift in these divided flow passage enlarged portions. A fluidic flowmeter in which a plurality of measuring parts are formed in parallel by arranging at a symmetrical position.