JPH0545931Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention forms a conduit constriction section, a jet nozzle, and a conduit expansion section in sequence in the flow direction, and A pair of control nozzles are formed at the boundary portion so as to face each other in a direction substantially perpendicular to the jetting direction of the jetting nozzle;
forming a pair of return flow paths connecting each of the control nozzles and the downstream side of the expanded pipe section, providing a target for stabilizing flow direction switching in the expanded pipe section, and connecting to the contracted pipe section; A phenomenon in which the jet flow from the jet nozzle is stabilized along one slope of the expanded pipe section, and a phenomenon in which the jet flow from the jet nozzle is stabilized along both slopes of the expanded pipe section by alternately jetting fluid from the control nozzle. The present invention relates to a fluidic flowmeter equipped with a flow rate measurement sensor that detects a change in pressure or flow rate caused by a change in the flow direction of a jet flow from a jet nozzle, so as to measure the flow rate by utilizing the phenomenon in which the jet flow alternately flows along the jet nozzle.

[Conventional technology]

Conventionally, as shown in FIG. 4, a pair of partition walls 17a, 17b defining the conduit enlarged part 5, control nozzles 6a, 6b, and return channels 7a, 7b are formed into airfoil shapes, and the conduit enlarged part 5 The target 12 is placed on the downstream side within
The partition surface C formed opposite to b is defined by its opposing width l.
was formed so that it became smaller toward the control nozzles 6a and 6b.

[Problem that the invention attempts to solve]

However, increasing the measurement flow rate range resulted in large errors in measuring minute flow rates, leaving room for further improvement.

The purpose of the present invention is to accurately measure the flow rate regardless of the flow rate while sufficiently widening the measurement flow rate range by simply improving the shape of the partition wall, the arrangement of the target, and the arrangement of the discharge channel relative to the expanded pipe section. The point is to make it possible.

[Means for solving problems]

A characteristic configuration of the present invention is that a pair of partition walls that define a conduit expansion section, a control nozzle, and a return flow path are provided with a cylindrical or nearly cylindrical outer peripheral surface, and the centers of the outer peripheral surfaces of the two partition walls are connected to each other. A surface of a target for stabilizing flow direction switching in the conduit enlarged portion facing toward the ejection nozzle is disposed between the straight line and a straight line connecting the tips of the two partition walls on the control nozzle side, and Of the partition walls forming the terminal end portions of both return flow paths, the partition surface facing the cylindrical or substantially cylindrical outer circumferential surface is formed into a cylindrical surface that is concentric or substantially concentric with the outer circumferential surface, The pair of discharge passages for the pipe expansion part are formed such that the inlet is located near a straight line connecting the centers of the outer peripheral surfaces of the return flow passage, and the effects thereof are as follows. .

[Effect]

In other words, as a result of experimenting to find out what shape the partition walls should be, where the target should be placed, what shape the return channels should be, and how the discharge channel should be connected, the flow rate measurement error could be reduced. The facts have been revealed.

As shown in FIG. 1, both partition walls 8a and 8b are provided with cylindrical or nearly cylindrical outer peripheral surfaces, and between a straight line X connecting the centers of the outer peripheral surfaces and a straight line Y connecting the tips of both partition walls 8a and 8b. [Including both straight lines X and Y]
In addition, the surface 12a of the target 12 on the side of the jet nozzle 3
are arranged, and a return flow path 7 is arranged facing the partition walls 8a and 8b.
The partition wall surface A forming the terminal end portions of the return channels 7a and 7b is formed into a cylindrical surface concentric with the outer peripheral surfaces of the partition walls 8a and 8b, so that the entire terminal end portions of the return channels 7a and 7b have approximately the same width. furthermore, a pair of discharge passages 10a,
10b near the above-mentioned straight line
By connecting to ports a and 7b, as shown in Figure 2, a wide range of flow from the maximum flow rate (3000/h) to 1/20 of the maximum flow rate (150/h) can be achieved with an error of ±1.0.
It has been found that accurate measurements can be made in conditions where the value is less than %.

On the other hand, in the conventional technology shown in Fig. 4, the error in the same flow rate range (3000 to 150/h) is
As shown in Figure 5, the micro flow rate range (150~300/
h) becomes larger by up to 10% or more, and as is clear from the comparison of Figures 2 and 5, according to the present invention, the flow rate measurement range can be increased while even minute flow rates can be measured. Measurements can be made accurately.

[Effect of idea]

As a result, it has become possible to accurately measure minute flow rates with an extremely simple modification that involves simply changing the shape of the partition wall, the placement of the target, and the connection position of the discharge channel, allowing the use of fluidic flowmeters to be expanded. It became.

〔Example〕

Next, an example will be shown with reference to FIG.

A pair of first flow path forming members 4a and 4b forming the conduit constriction section 2 and the jet nozzle 3 in the tube 1 are arranged symmetrically with respect to the tube center axis P, and the conduit constriction section 2 is arranged symmetrically with respect to the tube center axis P.
The fluid is smoothly guided to the jet nozzle 3 by the action of the jet nozzle 3, and the fluid is jetted from the jet nozzle 3 substantially parallel to the pipe center axis P. And the pipe expansion part 5
A pair of partition walls 8a, 8b defining a pair of return passages 7a, 7b which respectively communicate with the downstream side of the control nozzles 6a, 6b are arranged symmetrically with respect to the pipe center axis P, and a pair of control The nozzles 6a and 6b are oriented substantially perpendicular to the ejection direction of the ejection nozzle 3 and are opposed to each other. A pair of bulkheads 9
A pair of discharge passages 10a, 10b in cooperation with a, 9b
A partition wall 11 is provided to block the downstream side of the expanded pipe section 5.

That is, when fluid ejection from the ejection nozzle 3 is started, the ejected fluid flows along one partition wall 8a due to the Coanda effect, and therefore, the ejection fluid flows along one partition wall 8a.
Large fluid energy is applied from the return flow path 7a to the control nozzle 6a located on the side, and the ejected fluid flows along the partition wall 8b on the opposite side, and this time, the fluid energy from the control nozzle 6b on the opposite side is applied. As a result, the ejected fluid again flows along the partition wall 8a along which it initially ran, and in this way, the fluid from the ejection nozzle 3 is configured to alternately follow the partition walls 8a and 8b, and thus, The flow direction of the ejected fluid is configured to change in a shorter cycle as the amount of ejected fluid increases, and in a state where there is a quantitative correlation.

Both the partition walls 8a and 8b are formed into a columnar shape or almost a columnar shape, and the target 12 for stabilizing the switching of the flow direction in the conduit expansion section 5 is a straight line X connecting the centers of the outer peripheral surfaces of the partition walls 8a and 8b. Both bulkheads 8a,
Between the straight line Y connecting the tips of control nozzles 6a and 6b of 8b, there is a surface 1 facing the jet nozzle 3 side.
2a is located. Further, a partition wall 9 forming the terminal end portion of both return channels 7a and 7b.
Of the partition walls 8a and 9b, the partition wall surface A facing the outer peripheral surface of the partition walls 8a and 8b is formed into a cylindrical surface concentric or almost concentric with the outer peripheral surface, and a pair of discharge passages 10a to the conduit enlarged portion 5 are formed. , 10b, the inlet is the return flow path 7
It is formed so as to be located near the straight line X connecting the centers of the outer circumferential surfaces of a and 7b. In other words, by combining these configurations, the second
As shown in the figure, the measured flow rate range is, for example, 150 to 3000, which is required for a residential city gas meter.
h, while the error in flow rate measurement can be made small, for example, within ±1% or less, which is within the certification tolerance of a city gas household gas meter.

In addition, the partition wall surface B forming the starting end side portion of the return channels 7a and 7b of the partition wall 11 is formed into a cylindrical surface located approximately on the same circumferential surface as the partition wall surface A, so that the The structure is designed to further reduce measurement errors.

Out of both return channels 7a, 7b, discharge channels 10a, 1
The pipes 13a and 13b, which are connected to the partition wall 11 side separately near the entrance of
A pressure sensor 14 is installed inside both pipes 13a and 13b.
The pressure sensor 14 detects the pressure change caused by the change in the flow direction of the jet flow from the jet nozzle 3, and the pressure sensor 14 transmits a sinusoidal waveform to the flow rate measuring device 15. A waveform signal is sent, and the flow rate measuring device 15 is configured to calculate and display the flow rate from the frequency of the waveform signal, thereby forming a feedback type fluidic flowmeter.

The inlets of the discharge passages 10a and 10b are arranged on a plane Z that is substantially parallel to the pipe center axis P, and the waveform signal from the pressure sensor 14 is arranged evenly during large flow rates, so that flow rate measurement is possible even during large flow rates. It is designed to improve accuracy.

[Another example]

Next, another embodiment will be described.

The partition walls 8a, 8b may be cylindrical or approximately cylindrical.

The surface 12a of the target 12 on the jet nozzle 3 side may be arranged on the straight lines X and Y.

The shape of the partition wall 11 can be changed appropriately.

Further, as shown in FIG. 3, partition walls 9a, 9b,
11 are integrally formed, and the partition surfaces A and B are connected to the partition walls 8a,
It may be continuously formed in a cylindrical shape concentric with 8b,
Then, the inlets E ₁ and E ₂ of the discharge passages 10a and 10b may be formed in the pipe 1 to reduce the width L of the flowmeter. A plurality of inlets E ₁ and E ₂ of 10b may be formed.

A sealed case 16 externally disposed with pipes 13a and 13b communicating with both return channels 7a and 7b, respectively.
may be connected to. Further, the pressure sensor 14 may be provided to detect a pressure change in one of the return channels 7a or 7b, and in that case, the pressure sensor 14 may be arranged in the return channel 7a or 7b. Furthermore, a flow rate sensor may be provided in place of the pressure sensor, and these sensors 14 may be placed in either of the return channels 7a and 7b.

Flowmeters are mainly used for industrial and household purposes, such as fuel gas and water supply, but their uses are not specific.

Note that although reference numerals are written in the claims section of the utility model registration for convenience of comparison with the drawings, the present invention is not limited to the structure of the attached drawings by such entry.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a graph showing experimental results of the present invention. FIG. 3 is a sectional view showing another embodiment of the present invention. FIG. 4 is a sectional view showing a conventional example, and FIG. 5 is a graph showing experimental results of the conventional example. 2...Pipe reduction part, 3...Blowout nozzle, 5...
Pipe expansion portion, 6a, 6b...control nozzle, 7a,
7b... Return flow path, 8a, 8b... Partition wall, 9a,
9b... Bulkhead, 10a, 10b... Discharge path, 12
...Target, 12a...The surface of the target on the jet nozzle side, 14...Sensor, A...The partition wall surface,
X, Y...straight line.

Claims (1)

[Scope of utility model registration request] Pipe reduction section 2, jet nozzle 3, and pipe enlargement section 5
are formed in series in the flow direction, and a pair of control nozzles 6a and 6b are provided at the boundary between the jet nozzle 3 and the expanded pipe section 5, oriented in a direction substantially perpendicular to the jet direction of the jet nozzle 3. A pair of return flow passages 7a and 7b are formed to face each other and connect the control nozzles 6a and 6b to the downstream side of the conduit enlarged part 5, respectively. Target 12 for stabilizing flow direction switching in
The fluidic flowmeter is equipped with a flow rate measurement sensor 14 that detects a change in pressure or flow rate caused by a change in the flow direction of the jet flow from the jet nozzle 3, and the fluidic flowmeter is provided with a flow rate measurement sensor 14 that detects a change in pressure or flow rate caused by a change in the flow direction of the jet flow from the jet nozzle 3, and the flow rate measurement sensor 14 is provided with a sensor 14 for measuring a flow rate, which
A pair of partition walls 8a, 8b that define the return channels 7a, 7b are provided with a cylindrical or substantially cylindrical outer peripheral surface, and a straight line X connecting the centers of the outer peripheral surfaces of the partition walls 8a, 8b is provided. and both partition walls 8a,
A surface 12a of the target 12 facing the jet nozzle 3 is disposed between the straight line Y connecting the tips of the control nozzles 6a and 6b of the target 8b, and the end portion of both the return channels 7a and 7b is Of the partition walls 9a and 9b forming the duct, the partition surface A facing the cylindrical or substantially cylindrical outer circumferential surface is formed into a cylindrical surface concentric or substantially concentric with the outer circumferential surface, and the conduit expansion A pair of discharge passages 10a, 10b for section 5
A fluidic flowmeter in which the inlet is located near a straight line X connecting the centers of the outer peripheral surfaces of the return channels 7a and 7b.