JP3910778B2 - Fluidic element manufacturing method, fluidic element, fluidic flow meter, combined flow meter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluidic element manufacturing method, a fluidic element, a fluidic flow meter, and a composite flow meter that detect fluidic vibration corresponding to a change in fluid flow rate.
[0002]
[Prior art]
Various proposals have been made for this type of fluidic type flow meter. For example, the example described in JP-A-8-210886 uses a fluidic element 100 as shown in FIG. The fluidic element 100 includes a flow path formed by sequentially connecting a fluid inlet 101, a nozzle 102, a flow path expanding portion 103, and a fluid discharge port 104, and an outlet of the nozzle 102 disposed in the flow path expanding section 103. It has an opposing pendulum 105 and an end block 106 arranged on the downstream side thereof.
[0003]
In the fluidic flow meter using such a fluidic element 100, the fluid ejected from the nozzle 102 toward the downstream side is alternately distributed along the outside of the attracting element 105. Referring to FIG. 8, the state in which the fluid flows below the attracting element 105 is described. Most of the fluid ejected from the nozzle 102 flows from the flow path expanding portion 103 toward the fluid discharge port 104, but a part thereof is the end block 106. It hits and becomes a return fluid along the lower side wall of the flow path expanding portion 103, and hits the jet of fluid newly ejected from the nozzle 102 from a right angle direction. Due to the energy of the return fluid, a jet of the fluid newly ejected from the nozzle 102 now flows to the upper side of the attracting element 105, and a part thereof collides with the end block 106 and returns to the return fluid along the upper side wall of the flow path expanding portion 103. Thus, a new jet of fluid ejected from the nozzle 102 collides from the right angle direction. Due to the energy of the return fluid, a fluid jet newly ejected from the nozzle now flows below the attracting element 105. The distribution of the flow of the jet ejected from the nozzle 102 is repeated in this way.
[0004]
A fluidic type flow meter detects the frequency of vibration (alternating pressure wave) generated in a fluid as described above by a pressure sensor, and converts the detected output into an electrical signal to measure the fluid flow rate. Is.
[0005]
In a fluidic type flow meter, when a fluid is ejected from a nozzle 102 having a certain width toward the attracting element 105, a high-speed flow “jet” that is faster than the flow velocity of the surrounding fluid and an attracting element placed in the flow. The relationship with the “wake” seen on the downstream side of 105 is important, and the shape of the attractor 105 plays an extremely important role in the fluidic vibration characteristics when considered in a two-dimensional field.
[0006]
More specifically, when the “jet” from the nozzle 102 is ejected into a semi-infinite space, the direction of the “jet” is stable, but the space of the flow path expanding portion 103 is limited, and an attractor 105 is provided at the center. Therefore, the jet cannot maintain the direction of the initial velocity when ejected from the nozzle 103, so that the two-dimensional jet becomes unstable, and this instability is considered to cause the start of fluidic oscillation. On the other hand, an asymmetrical vortex (Karman vortex) is generated on the downstream side of the attracting element 105 arranged in the flow, and this vortex row becomes a meandering flow. Therefore, it is considered that the “wake flow” becomes an oscillating flow and cannot be stabilized. As described above, both the “jet flow” and the “wake flow” are unstable due to the influence of the shape of the attracting element 105 and the wall surface of the flow path expanding portion 103.
[0007]
[Problems to be solved by the invention]
The current fluidic type flowmeter has poor linearity in the small flow rate range, but is suitable for measurement in the large flow rate range. For example, in a gas meter that measures the flow rate of city gas, the flow is suitable for measurement in the small flow rate range. A combined flow meter having a thermal flow detection sensor such as a sensor and a fluidic flow meter is used.
[0008]
Thus, the fluidic flow meter has a low minimum vibration flow rate (fluidic vibration start flow rate), and a wide dynamic range is desired for the flow rate range. If the fluid vibration start amount of the fluidic type flow meter can be used from 0 flow rate, a flow meter using only the fluidic type flow meter can be realized without using a thermal flow rate detection sensor.
[0009]
Even if this is not the case, the specification of the thermal flow rate detection sensor can be relaxed if the flow rate at the start of the stable fluid vibration of the fluidic flow meter can be lowered as much as possible. That is, in the current combined flow meter, for example, a full scale of 4000 L (liter) / H (hours), a range of 200 L / h to several thousand L / h is handled by a fluidic flow meter, and a range of 0 to 200 L / h. Is handled by a thermal flow sensor. For this reason, since the flow range of the thermal type flow detection sensor is as many as two digits, there is a drawback that it is difficult to obtain measurement accuracy in a small flow range. As a result, strict specifications are required for the performance of the thermal flow rate detection sensor, and complex signal processing and flow rate correction calculation processing are required when used as a flow meter.
[0010]
Therefore, even if the fluid vibration start amount of the fluidic type flow meter can be reduced to 100 L / h or less (80 to 90 L / h), improvement in signal processing ease, reliability, and manufacturing cost is achieved. The impact on is great.
[0011]
For this reason, the present applicant has experimentally studied the flow rate (minimum vibration detection flow rate) and flow rate-frequency characteristics when vibration is started to be detected by a fluidic type flow meter. It was found that the shape of the corner at the edge of the opening was an important control factor. Specifically, it is desirable that the shape of the corner of the opening edge on the outlet side of the nozzle is an edge, but if a burr occurs during manufacturing, the flow state is disturbed between the part where the burr exists and the part where the burr does not exist. End up. For this reason, in the case of manufacturing by mold molding, it is necessary to form a curved surface so as not to generate burrs. However, it has been found that as the radius of the curved surface increases, the variation in the separation position of the jet with respect to the opening edge of the nozzle increases, and as a result, the linearity in a small flow rate region deteriorates.
[0012]
Accordingly, an object of the present invention is to stabilize fluidic vibration in a small flow rate region and to expand a flow rate measurement region based on fluidic vibration output to the small flow rate region side.
[0013]
[Means for Solving the Problems]
  In view of the above problems, the invention according to the present application is arranged in the flow passage enlargement portion at a position facing the nozzle and the flow passage enlargement portion wider than the cross-sectional area of the nozzle, and the outlet of the nozzle. When the fluidic element having the attractor and the end block disposed in the flow passage enlarged portion at a position on the downstream side of the attractor is integrally molded by a mold,The fluidic element is molded so as to satisfy a tolerance that the opening edge of the nozzle has a curved surface of R / d = 0.125 or less, where d is the nozzle width and R is the radius. ,It is characterized by that.
[0014]
  Therefore, in the fluidic element manufactured by this method, when the fluid is ejected from the nozzle, the fluctuation of the fluid separation position at the opening edge is reduced, and the jet direction is stabilized.In addition, since the radius of the curved surface is given specifically, when the fluid is ejected from the nozzle, the fluctuation of the separation position of the fluid at the opening edge is suppressed to a certain range or less, and the jet direction is stabilized.
[0029]
  In view of the above problems, the invention according to the present application is arranged in the flow passage enlargement portion at a position facing the nozzle and the flow passage enlargement portion wider than the cross-sectional area of the nozzle, and the outlet of the nozzle. And an end block arranged in the flow passage enlargement portion at a position downstream of the attractor, and the flow of the fluid ejected from the nozzle is distributed to the left and right around the attractor In a fluidic element that generates an alternating pressure wave,When the width of the nozzle is d and the radius is R, the opening edge on the outlet side of the nozzle is formed as a curved surface with R / d = 0.125 or less.It is characterized by that.
[0030]
  Therefore, when the fluid is ejected from the nozzle, the fluctuation of the fluid separation position at the opening edge is reduced, and the jet direction is stabilized. Also,Since the radius of the curved surface is specifically given, when the fluid is ejected from the nozzle, the fluctuation of the separation position of the fluid at the opening edge is suppressed to a certain range or less, and the direction of the jet is stabilized.
[0049]
  Claim3The fluidic type flow meter described in claim2And a pressure sensor that outputs a signal corresponding to an alternating pressure wave generated by the fluidic element.
[0050]
Therefore, when the fluid is ejected from the nozzle, the fluid separation position at the opening edge is less changed, and a fluidic flow meter that can stabilize the direction of the jet can be provided.
[0051]
Claim4The combined flow meter described in claim3The fluidic flow meter described above and a small flow rate detection element for detecting the flow rate of the fluid in the small flow rate range.
[0052]
Therefore, when the fluid is ejected from the nozzle, the fluctuation of the separation position of the fluid at the opening edge is reduced, and a composite flow meter that can stabilize the jet direction can be provided.
[0053]
Claim5The combined flow meter described in claim4In the invention described above, the small flow rate region detecting element is disposed on the inlet side of the nozzle of the fluidic type flow meter.
[0054]
Therefore, the claims4The same effect as that of the described invention is obtained, and in addition, the configuration of the flow path is simplified.
[0055]
Claim6The combined flow meter described in claim4In the described invention, the small flow rate region detecting element is disposed in a small flow rate channel formed at a position not affected by a fluid flow fluctuation by the nozzle of the fluidic flow meter.
[0056]
Therefore, the claims4The operation equivalent to that of the described invention can be obtained, and in addition to this, when the flow rate of the fluid is measured by the output of the small flow rate region detecting element, the measurement can be performed regardless of the fluctuation of the fluid flow in the nozzle.
[0057]
Claim7The combined flow meter described in claim4 to 6In any one of the inventions, a thermal flow rate detection sensor is used as the small flow rate region detection element.
[0058]
Therefore, the claims4 to 6In addition to this, the measurement sensitivity in a small flow rate region can be increased.
[0059]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a fluidic element, and FIG. 2 is a plan view showing a schematic structure of a composite flow meter.
[0060]
First, the configuration of the fluidic element 1A will be described with reference to FIG. The fluidic element 1A sequentially includes a flow restrictor 2 and a nozzle 3 whose flow cross-sectional area is reduced in the direction of fluid flow indicated by an arrow, and a flow passage expanding part 4 having a larger cross-sectional area than the nozzle 3. Connected flow path 5, attractor 7 disposed in flow path expanding part 4 at a position facing outlet 6 of nozzle 3, and flow path expanded part 4 at a position downstream of this attractor 7. The end block 8 is disposed, and a center line passing through the center of the nozzle 3 is formed of a plastic material with a symmetrical shape therebetween. The upstream end of the flow restrictor 2 and the downstream end of the flow enlarged portion 4 are open. A plurality of grooves 9 are formed on the wall surfaces on both sides of the flow restrictor 2.
[0061]
Such a fluidic element 1A is incorporated in the flow meter main body 10 as shown in FIG. 2, and the upper opening is covered with a lid (not shown) that closes the upper surface of the flow meter main body 10. A pressure sensor (not shown) is attached to the upper surface of the lid. This pressure sensor detects the alternating pressure wave of the fluidic element 1A through holes 11 arranged on both sides on the outlet 6 side of the nozzle 3 and formed in the lid, and outputs an electrical signal corresponding to the detected pressure. To do. Further, a rectifying network 12 and a rectifying grid 13 are incorporated in the groove 9 formed in the fluidic element 1A.
[0062]
The flow meter body 10 is formed with a fluid inlet 14, a fluid outlet 15, and a flow path 16 for flowing a gas as a fluid from the fluid inlet 14 toward the fluid outlet 15. The fluidic element 1A is arranged in the part. The fluidic element 1 </ b> A has an upstream side of the flow path restricting portion 2 connected to the fluid inlet 14, and an outlet side of the flow path expanding portion 4 is connected to the fluid outlet 15. Furthermore, a shutoff valve 18 is assembled in the flow path 16 on the upstream side of the fluidic element 1A so that the drive section 17 shuts off the flow path 16 when subjected to abnormal vibration such as an earthquake. The fluidic flow meter 20 is configured by the above assembly.
[0063]
Furthermore, by disposing a thermal type flow rate detection sensor (hereinafter referred to as a flow sensor in the embodiment) 19 as a small flow rate detection element on the inlet side of the nozzle 3 of the fluidic element 1A, the composite flow meter 30 is provided. It is configured. Since the flow sensor 19 outputs an electrical signal corresponding to the gas flow rate, the gas flow rate is measured based on the output.
[0064]
The fluidic element 1 </ b> A, which is a main component of the fluidic flow meter 20, is configured such that when the gas flowing in from the fluid inlet 14 is ejected downstream from the nozzle 3, the gas alternates along the outside of the attracting element 7. It is distributed to. Referring to FIG. 2, the gas flows from the upper side of the attracting element 7. Most of the gas ejected from the nozzle 3 flows from the flow passage expanding portion 4 toward the fluid outlet 15, but a part thereof is the end block 8. It collides with and becomes a return fluid along the upper side wall of the flow path expanding section 4 and hits a jet of gas newly ejected from the nozzle 3 from a substantially right angle direction. Due to the energy of the return fluid, the gas jet newly ejected from the nozzle 3 now flows below the attractor 7 and partly collides with the end block 8 along the lower side wall of the flow path expanding portion 4. It becomes a return fluid and collides with a jet of gas newly ejected from the nozzle 3 from a substantially perpendicular direction. Due to the energy of the return fluid, a jet of gas newly ejected from the nozzle 3 now flows on the upper side of the attractor 7. The distribution of the flow of the jet ejected from the nozzle 3 is repeated by such a Coanda effect. The fluid vibration (alternating pressure wave) generated in this way is detected by a pressure sensor, and the gas flow rate is measured by converting the period of the output into an electric signal and recognizing it.
[0065]
By the way, the fluidic element 1A is molded by a plastic material such as ABS (Alkyl Benzene Sulfonate), PBT (Poly Butyrene Terephthalate), PC (polycabonate), POM (Polyacetal resin), BMC (Bulk Molding Compound). In this case, in order to reduce the dimensional change after molding, the plastic material has different shrinkage ratios depending on the direction, but ABS, PBT, PC, etc. having an average shrinkage ratio as low as about 5/1000 is preferable.
[0066]
Further, since a mold is used when the fluidic element 1A is molded, burrs are particularly likely to occur at the opening edge 6a on the outlet 6 side of the nozzle 3 serving as a joint of the mold. As described above, the burrs cause the flow to be disturbed when the fluid is ejected from the nozzle 3. In order to avoid the occurrence of this burr, a curved surface is formed at the opening edge 6a of the nozzle 3. If the radius of the curved surface is too large, the variation in the fluid separation position becomes large. Further, it is very difficult to set the curved surface to a constant value by finishing or the like.
[0067]
Therefore, the fluidic element 1A is molded so as to satisfy a tolerance that the opening edge 6a on the outlet 6 side of the nozzle 3 is a curved surface having a certain radius or less. Here, the constant radius is R / d = 0.125 or less, where d is the nozzle width and R is the radius. More preferably, R / d = 0.075. Since the width d of the nozzle 3 is 4 mm in this example, the former radius is 0.5 mm and the latter radius is 0.3 mm.
[0068]
Therefore, the opening edge 6a on the outlet 6 side of the nozzle 3 of the fluidic element 1A manufactured by such a method is maintained in a curved surface state having a radius of 0.5 mm or less from an edge state without burrs. Yes.
[0069]
In such a configuration, when the gas is ejected from the nozzle 3, the fluctuation of the gas separation position at the opening edge 6a is reduced, and the jet direction is stabilized.
[0070]
Further, the fluidic element 1A is designed so as to satisfy a tolerance that the entire area of the opening edge 6a of the nozzle 3 in the height direction parallel to the layer direction of the gas flow flowing through the nozzle 3 is uniformly curved with a certain radius or less. The opening edge 6a of the fluidic element 1A thus molded is maintained in a curved state having a radius of 0.5 mm or less from an edge state where the entire area in the height direction is uniformly free of burrs. . Therefore, the jet direction is stable even in a two-dimensional field.
[0071]
Further, the fluidic element 1A is molded so as to satisfy a tolerance that both sides of the opening edge 6a having a center line passing through the center of the nozzle 3 are uniformly curved surfaces having a certain radius or less. Further, the opening edge 6a of the fluidic element 1A is maintained in a curved surface state having a radius of 0.5 mm or less from an edge state in which both sides are uniformly free of burrs. Therefore, the jets are distributed evenly by the Coanda effect.
[0072]
Here, FIG. 3 and FIG. 4 show the experimental results when the radius of the curved surface of the opening edge 6a on the outlet 6 side of the nozzle 3 is R / d = 0.125 (radius 0.5 mm).
[0073]
FIG. 3 is a graph in which the period of fluidic vibration (alternating pressure wave) in a small flow rate range of 150 L / h, 180 L / h, 200 L / h, and 300 L / h is measured over 100 pulses for each flow rate range. . FIG. 4 is a graph in which the frequency of alternating pressure wave vibrations in a large flow rate range of 3500 L / h, 4000 L / h, 5000 L / h, and 6000 L / h was measured over 100 pulses for each flow rate range.
[0074]
As can be seen in FIGS. 3 and 4, the period of fluidic oscillation becomes longer as the flow rate region is lower. As shown in this graph, the vibration period may be very long in a certain flow rate range. For example, in the flow rate range of 150 L / h, the period of about 0.6 sec was measured, but there are times when the period is as long as 1.2 pulses, which is twice as long as 3 pulses. This is referred to as missing pulse and means that the alternating pressure wave is missing. The cause is that when the gas is ejected from the nozzle 3, the gas peeling position with respect to the opening edge 6a deviates greatly at a certain moment. However, this deviating rate is 3 pulses or less out of 100 pulses, which is a value that falls within the range of 3% of the instrumental tolerance allowed by the measurement method in a small flow rate range of 200 L / h to 400 L / h or less. .
[0075]
The instrumental difference in the flow rate region of 400 L / h or more is set to a low value of 1.5%, but only one pulse out of 100 pulses deviates in the large flow rate region up to 5000 L / h as shown in FIG. Since the results are shown, it is well within the range of 1% instrumental error. Furthermore, at 6000 L / h, which is a large flow rate region, only 2 out of 100 pulses deviated. However, the allowable value of the instrumental error of 1.5% allows some allowance, and several fluidic vibrations have occurred. This is a value that does not pose a significant problem when the flow rate is measured by detecting by sampling. This value is an improved value over the prior art.
[0076]
In order to further improve the linearity in the low flow rate region, the radius of the curved surface of the opening edge 6a on the outlet 6 side of the nozzle 3 is preferably set to R / d = 0.075 (radius 0.3 mm). Hereinafter, experimental results when the radius of the curved surface of the opening edge 6a is set to R / d = 0.075 are shown in FIGS.
[0077]
FIG. 5 is a graph in which the period of fluidic vibration in a small flow rate region of 150 L / h, 180 L / h, 200 L / h, and 300 L / h is measured over 100 pulses for each flow rate region. FIG. 6 is a graph in which the period of fluidic vibration in a large flow rate region of 3500 L / h, 4000 L / h, 5000 L / h, and 6000 L / h is measured over 100 pulses for each flow rate region.
[0078]
As can be seen from this result, no missing pulse occurs in 100 pulses. That is, it can be seen that the fluidic type flow meter 20 satisfies the instrumental error of the measuring method over a wide range.
[0079]
In the present embodiment, since the flow sensor 19 is disposed on the inlet side of the nozzle 3 of the fluidic element 1, the configuration of the flow path 16 as the composite flow meter 30 can be simplified.
[0080]
Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is also omitted. FIG. 7 is a plan view showing a schematic structure inside the composite flow meter. The difference between the fluidic element 1B of the present embodiment and the fluidic element 1A of the embodiment is that
(1) The outline of the plane of the fluidic element 1B is rectangular.
(2) Increase in the number of grooves 9 to mount a plurality of rectifying networks 12
(3) The small flow passage 21 is formed on the side wall of the passage restricting portion 2 to join.
It is. The opening edge 6a on the outlet 6 side of the nozzle 3 has a curved surface with a certain radius or less, as in the above embodiment.
[0081]
In such a fluidic element 1B, a plurality of rectifying networks 12 and rectifying grids 13 are assembled in the groove 9, and then an upper opening is covered with a lid (not shown), and a pressure sensor (not shown) is formed on the upper surface of the lid. The fluidic type flow meter 40 is configured by attaching a Further, the composite flow meter 50 is configured by disposing the flow sensor 19 in the small flow channel 21.
[0082]
In such a configuration, the small flow channel 21 is formed on the upstream side of the nozzle 3, and the thermal flow rate detection sensor 19 is disposed in the small flow channel 21. When the gas flow rate is measured by the above, it can be measured without being influenced by the fluctuation of the gas flow in the nozzle 3.
[0083]
【The invention's effect】
In the fluidic element manufacturing method according to claim 1, the opening edge on the outlet side of the nozzle stabilizes the ejection direction of the fluid ejected from the nozzle.The fluidic element is molded so as to satisfy a tolerance that the opening edge of the nozzle has a curved surface of R / d = 0.125 or less, where d is the nozzle width and R is the radius.Therefore, when the fluid is ejected from the nozzle, the fluctuation of the separation position of the fluid at the opening edge is reduced,Since the radius of the curved surface is given concretely, when the fluid is ejected from the nozzle, the fluctuation of the fluid separation position at the opening edge can be suppressed to a certain range or less, and the jet direction can be stabilized.
[0084]
In addition, according to the present applicationThe fluidic element manufacturing method, as a method of smoothing the opening edge on the outlet side of the nozzle, because the fluidic element is molded so as to satisfy the tolerance that the opening edge becomes a curved surface having a certain radius or less, The same effect as that of the first aspect of the invention can be obtained.
[0085]
In addition, according to the present applicationThe manufacturing method of the fluidic element is such that the entire area of the nozzle opening edge in the height direction parallel to the layer direction of the fluid flow through the nozzle satisfies a tolerance such that the entire surface of the nozzle becomes a curved surface having a certain radius or less. Since the dick element is molded, the direction of the jet can be stabilized even in a two-dimensional field.
[0086]
In addition, according to the present applicationSince the fluidic element manufacturing method molds the fluidic element so as to satisfy the tolerance that the both sides of the opening edge with the center line passing through the center of the nozzle in between are uniformly curved surfaces with a certain radius or less, The direction of the jet can be stabilized, and further, the distribution of the jet can be made uniform, and the pulse omission of fluidic vibration can be effectively prevented.
[0087]
In addition, according to the present applicationSince the fluidic element manufacturing method molds the fluidic element so as to satisfy the tolerance that the both sides of the opening edge with the center line passing through the center of the nozzle in between are uniformly curved surfaces with a certain radius or less, Even in a two-dimensional field, the direction of the jet is stable, and the jets can be evenly distributed.
[0089]
In addition, according to the present applicationThe manufacturing method of the fluidic element is such that when the width of the nozzle is d and the radius is R, the opening edge on the outlet side of the nozzle satisfies a tolerance such that a curved surface with R / d = 0.075 or less is satisfied. Because the dick element is molded, fluctuation of the fluid separation position at the opening edge when fluid is ejected from the nozzleTheCan be further suppressed.
[0090]
In addition, according to the present applicationIn the fluidic element manufacturing method, since the fluidic element is molded using a plastic material, a fluidic element capable of stabilizing the jet direction can be obtained inexpensively and easily.
[0091]
According to this applicationThe fluidic element has an opening edge on the outlet side of the nozzle to stabilize the ejection direction of the fluid ejected from the nozzle.When the nozzle width is d and the radius is R, the opening edge on the outlet side of the nozzle is formed as a curved surface with R / d = 0.125 or less, so the radius of the curved surface is given specifically. For,When fluid is ejected from the nozzle, the fluctuation of the fluid separation position at the opening edge is suppressed to a certain range or less, the fluidic vibration in the small flow rate range is stabilized, and the flow measurement area by the fluidic vibration output is in the small flow rate range Can be spread to the side.
[0092]
In addition, according to the present applicationIn the fluidic element, the opening edge on the outlet side of the nozzle is formed as a curved surface having a certain radius or less, so that when the fluid is ejected from the nozzle, the fluctuation of the fluid separation position at the opening edge is reduced, and the jet flow This stabilizes the fluidic vibration in the small flow rate region and expands the flow rate measurement region by the fluidic vibration output to the small flow rate region side.
[0093]
In addition, according to the present applicationIn the fluidic element, the entire area of the nozzle opening edge in the height direction parallel to the layer direction of the fluid flow through the nozzle is uniformly formed as a curved surface having a certain radius or less. The direction of the jet can be stabilized.
[0094]
In addition, according to the present applicationIn the fluidic element, both sides of the opening edge with the center line passing through the center of the nozzle in between are formed as curved surfaces with a uniform radius or less uniformly, so that the direction of the jet can be stabilized. Can be evenly distributed, and the pulse omission of fluidic vibration can be effectively prevented.
[0095]
In addition, according to the present applicationIn the fluidic element, both sides of the opening edge between the center line passing through the center of the nozzle are uniformly formed as curved surfaces with a certain radius or less, so that the direction of the jet can be stabilized even in a two-dimensional field. Furthermore, the distribution of jets can be made uniform.
[0097]
  In addition, according to the present applicationIn the fluidic element, when the nozzle width is d and the radius is R, the opening edge on the outlet side of the nozzle is formed as a curved surface with R / d = 0.075 or less, so that fluid is ejected from the nozzle. Sometimes changes in fluid separation at the opening edgeMoveCan be further suppressed.
[0098]
In addition, according to the present applicationIn the fluidic element, when a curved surface is formed at the opening edge on the outlet side of the nozzle, the length of the arc of the curved surface is uniform throughout the height direction of the opening edge of the nozzle, so even in a two-dimensional field. The direction of the jet can be stabilized.
[0099]
The fluidic element according to the present application isWhen a curved surface is formed at the opening edge on the outlet side of the nozzle, the length of the arc of the curved surface is uniform on both sides of the opening edge of the nozzle, so that the jets can be evenly distributed.
[0100]
In addition, according to the present applicationSince the fluidic element is molded using a plastic material, a fluidic element capable of stabilizing the jet direction can be obtained inexpensively and easily.
[0101]
In addition, according to the present applicationThe fluidic type flow meter can provide a fluidic type flow meter that can reduce the fluctuation of the separation position of the fluid at the opening edge when the fluid is ejected from the nozzle, and can stabilize the direction of the jet.
[0102]
In addition, the composite flow meter according to the present application isWhen the fluid is ejected from the nozzle, it is possible to provide a composite flow meter that can reduce the fluctuation of the separation position of the fluid at the opening edge and can stabilize the jet direction.
[0103]
In addition, the combined flow meter according to the present application isSince the small flow rate region detecting element is arranged on the inlet side of the nozzle, the configuration of the flow path can be simplified.
[0104]
In addition, the combined flow meter according to the present application isSince the small flow rate detection element is arranged in a small flow channel formed at a position not affected by fluctuations in the flow of fluid due to the nozzle, when measuring the flow rate of the fluid by the output of the small flow rate detection element, Measurement is possible without being influenced by fluctuations in the flow of fluid in the nozzle.
[0105]
In addition, the combined flow meter according to the present application isSince the thermal flow rate detection sensor is used as the small flow rate region detecting element, the measurement sensitivity in the small flow rate region can be increased.
[Brief description of the drawings]
FIG. 1 is a perspective view of a fluidic element according to a first embodiment of the present invention.
FIG. 2 is a plan view showing a schematic structure of a composite flow meter.
FIG. 3 is a graph obtained by measuring the vibration cycle of an alternating pressure wave in a small flow rate region over 100 pulses for each flow rate.
FIG. 4 is a graph obtained by measuring the vibration cycle of alternating pressure waves in a large flow rate region over 100 pulses for each flow rate.
FIG. 5 is a graph obtained by measuring the vibration period of alternating pressure waves in a small flow rate range over 100 pulses for each flow rate.
FIG. 6 is a graph obtained by measuring the vibration period of alternating pressure waves in a large flow rate range over 100 pulses for each flow rate.
FIG. 7 is a plan view showing a schematic structure of a composite flow meter according to a second embodiment of the present invention.
FIG. 8 is a plan view showing a conventional fluidic element.
[Explanation of symbols]
1A, 1B Fluidic element
3 nozzles
4 Channel expansion section
5 Channel
6 Nozzle outlet
6a Open edge
7 Attractor
8 End block
19 Small flow rate detection element
20, 40 Fluidic type flow meter

Claims (7)

A flow path formed by connecting a nozzle and a flow path enlargement portion wider than the cross-sectional area of the nozzle, an attractor disposed in the flow path enlargement portion at a position facing the outlet of the nozzle, and a downstream side of the attractor When a fluidic element having an end block disposed in the flow passage enlarged portion at a position to be integrally molded with a mold,
The fluidic element is molded so as to satisfy a tolerance that the opening edge of the nozzle has a curved surface of R / d = 0.125 or less, where d is the nozzle width and R is the radius. ,
A method for producing a fluidic element, characterized in that: A flow path formed by connecting a nozzle and a flow path enlargement portion wider than the cross-sectional area of the nozzle, an attractor disposed in the flow path enlargement portion at a position facing the outlet of the nozzle, and a downstream side of the attractor A fluidic element that generates an alternating pressure wave by distributing the flow of fluid ejected from the nozzle to the left and right around the attracting element. ,
When the width of the nozzle is d and the radius is R, the opening edge on the outlet side of the nozzle is formed as a curved surface with R / d = 0.125 or less.
A fluidic element characterized by that.    A fluidic flow meter comprising: the fluidic element according to claim 2; and a pressure sensor that outputs a signal corresponding to an alternating pressure wave generated by the fluidic element.   A combined flow meter comprising the fluidic flow meter according to claim 3 and a small flow rate detection element for detecting a flow rate of a fluid in the small flow rate range.   5. The composite flow meter according to claim 4, wherein the small flow region detection element is disposed on an inlet side of the nozzle of the fluidic flow meter.   5. The composite flow meter according to claim 4, wherein the small flow region detection element is disposed in a small flow channel formed at a position not affected by fluid flow fluctuations caused by the nozzle of the fluidic flow meter.   The combined flow meter according to any one of claims 4 to 6, wherein a thermal flow rate detection sensor is used as the small flow rate range detection element.

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