JP7599147B2 - Physical Quantity Measuring Devices - Google Patents

Description

The present invention relates to a configuration for sampling a portion of a flowing fluid to measure characteristics such as the concentration of components contained in the fluid.

There are applications where it is necessary to measure the concentration of components contained in a fluid without being affected by turbulence in the fluid flowing through a channel.

Conventionally, a known measuring device for measuring the components of a fluid is one in which a component measuring section that samples the fluid flowing through the flow measuring section of an ultrasonic flowmeter is provided in addition to the flow measuring section (see, for example, Patent Document 1).

Figure 6 shows a cross-sectional view of a portion of the ultrasonic flowmeter described in Patent Document 1.

In this flowmeter, the measurement flow path 101 is divided into multiple layers by partition plates 102 to form a multilayer flow path 103. A sub-flow path 104 for measuring the components of the fluid is also provided in this multilayer flow path 103. A protrusion 105 is placed on the inlet side of the multilayer flow path 103 to the measurement flow path 101 to partially narrow the flow path cross section, and the ejector effect draws the fluid into the measurement flow path 101 from an opening 106 on the upstream side of the multilayer flow path 103a, causing the fluid in the gas meter to flow into the sub-flow path 104 from an opening not shown. Infrared rays are used in this sub-flow path 104 to measure the gas components in the mainstream.

International Publication No. 2018/185034

However, in the conventional configuration, in order to exert the ejector effect of drawing the fluid in the main flow path into the sub-flow path where the fluid components are measured, the cross section of the flow path must be partially narrowed, resulting in pressure loss. However, there is an issue that reducing this pressure loss does not provide sufficient suction force to cause the fluid to flow into the sub-flow path.

The present invention aims to solve the above-mentioned problems of the conventional technology by providing a measuring device that supplies a stable flow to a secondary flow path that measures characteristics such as the concentration of components contained in a fluid, and has a configuration that reduces pressure loss in the main flow path.

In order to solve the above-mentioned problems, the physical quantity measuring device of the present invention includes a first receding wall formed by receding the long side of a main flow passage having a rectangular cross section in an outward direction, an upstream opening provided on the upstream side of the first receding wall, a downstream opening provided on the downstream side of the first receding wall, and a sub-flow passage connecting the upstream opening and the downstream opening provided on the outward side of the first receding wall, the receding length of the first receding wall is configured so that a low pressure region formed by the Coanda effect of the fluid flowing in the main flow passage attracts a flow from the downstream opening, the height of the sub-flow passage is smaller than the height of the main flow passage , and the width of the sub-flow passage along a direction perpendicular to both the direction of the flow of the fluid to be measured and the direction of the height is smaller than the width of the main flow passage, thereby supplying a stable flow to the sub-flow passage and improving the measurement accuracy in the sub-flow passage. In addition, the pressure loss in the main flow passage can be reduced, and the turbulence of the flow in the main flow passage can be reduced.

In addition, the long side opposite the first receding wall is set back outward from the main flow path to form a second receding wall, and the setback length of the first receding wall is set shorter than the setback length of the second receding wall. By setting back both walls of the inlet section outlet, a state in which flow deflection is more likely to occur can be created, and the Coanda effect can be more reliably generated on the side with the smaller setback distance.

The long side opposite the first receding wall is set back outward from the main flow path to form a second receding wall, and the upstream side of the second receding wall is provided with a bias flow path that connects the approach opening in the approach section with the opening at the upstream end of the second receding wall. In addition to the deflection of the free jet flow toward the first receding wall due to the Coanda effect, the flow in the bias flow path further strengthens the adhesion of the free jet to the first receding wall, and the generation of flow in the secondary flow path can be further ensured.

The physical quantity measuring device of the present invention is equipped with a first receding wall formed by receding part of the long side of the main flow passage with a rectangular cross section outward, and the receding length of this first receding wall is configured so that the low pressure area formed by the Coanda effect of the fluid flowing through the main flow passage attracts the flow from the downstream opening, thereby providing a stable flow to the secondary flow passage and improving the measurement accuracy in the secondary flow passage, and also reducing pressure loss in the main flow passage and turbulence in the main flow passage.

FIG. 1 is a cross-sectional view showing a configuration of a physical quantity measuring device according to a first embodiment of the present invention. 1A is a plan view of a physical quantity measuring device according to a first embodiment of the present invention; FIG. FIG. 11 is a cross-sectional view showing the configuration of a physical quantity measuring device according to a second embodiment of the present invention. 3 in the second embodiment of the present invention. FIG. 11 is a cross-sectional view showing the configuration of a physical quantity measuring device according to a third embodiment of the present invention. Cross-sectional view showing the configuration of a conventional component measuring unit.

The first invention includes a main flow path with a rectangular cross section through which a fluid to be measured flows, an approach section formed by a part of the main flow path, a first receding wall formed by receding the long side of the main flow path with a rectangular cross section outward downstream of the approach section, an upstream opening provided on the upstream side of the first receding wall, a downstream opening provided on the downstream side of the first receding wall, a secondary flow path provided on the outer side of the first receding wall and connecting the upstream opening and the downstream opening, a pair of ultrasonic transmitter-receivers arranged in the secondary flow path, a temperature sensor for detecting the temperature of the fluid to be measured, and a signal processing unit for receiving signals from the pair of ultrasonic transmitter-receivers and signals from the temperature sensor to determine the component concentration of the fluid, and the receding length of the first receding wall is configured so that a low-pressure region formed by the Coanda effect of the fluid flowing through the main flow path attracts a flow from the downstream opening, thereby providing a stable flow to the secondary flow path, improving the measurement accuracy in the secondary flow path, reducing pressure loss in the main flow path, and reducing flow turbulence in the main flow path.

The second invention is characterized in that the long side opposite the first receding wall is set back outward from the main flow path to form a second receding wall, and the setback length of the first receding wall is set to be smaller than the setback length of the second receding wall. By setting back both walls of the inlet section outlet, a state in which flow deflection is likely to occur can be created, and the Coanda effect can be more reliably generated on the side with the smaller setback distance.

The third invention is characterized in that a second retreat wall is formed by receding the long side opposite to the first retreat wall outwardly of the main passage, and a bias passage is provided on the upstream side of the second retreat wall, connecting an inlet opening provided in the inlet section and an opening provided at the upstream end of the second retreat wall.In this way, in addition to deflecting the flow of the free jet towards the first retreat wall due to the Coanda effect, the flow of the bias passage can further strengthen the attachment of the free jet to the first retreat wall, and the generation of a flow in the secondary passage can be further ensured.

Below, an embodiment of the present invention will be described with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted.

The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
The first embodiment will be described with reference to FIGS. 1 and 2. FIG.

Figure 1 is a cross-sectional view of the configuration of a physical quantity measuring device in embodiment 1 of the present invention, Figure 2(a) is a plan view of embodiment 1 of the present invention as seen from direction G in Figure 1, and Figure 2(b) is a view as seen from direction A in Figure 1.

In Figures 1 and 2, the physical quantity measuring device 20 is composed of a main flow path section 21, a sub-flow path section 22, and a signal processing section 12. Inside the main flow path section 21, a main flow path 1 through which the fluid to be measured flows is formed, and inside the sub-flow path section 22, a sub-flow path 8 that communicates with the main flow path 1 is formed.

The main flow channel 1 through which the fluid to be measured flows is a rectangular flow channel with a large aspect ratio, with the long side 1a being the width W and the short side 1b being the height H, realizing a two-dimensional flow, and the main flow channel 1 has an inlet 2 and an outlet 3. An approach section 4 formed by a part of the main flow channel 1 is provided on the inlet 2 side of the main flow channel 1, and a first receding wall 5 formed by receding a part of the long side 1a outwardly of the main flow channel 1 by a receding length D is disposed downstream of this approach section 4. An upstream opening 6 is provided upstream of this first receding wall 5, and a downstream opening 7 is provided downstream of it.

Outside the main flow passage 1 of the first receding wall 5, a sub-flow passage 8 of length L is provided, connecting the upstream opening 6 and the downstream opening 7. In this sub-flow passage 8, a pair of ultrasonic transmitters 9 and 10 are arranged opposite each other in the flow direction, and a temperature sensor 11 is arranged to detect the temperature of the fluid.

The pair of ultrasonic transmitters and receivers 9, 10 and the temperature sensor 11 are electrically connected to a signal processing unit 12, which receives signals from the pair of ultrasonic transmitters and receivers 9, 10 and the temperature sensor 11 to measure the component concentrations of the fluid being measured.

The setback length D of the first setback wall 5 relative to the approach section 4 is set so that the low pressure region B formed by the Coanda effect of the fluid flowing through the main channel 1 attracts the flow from the downstream opening 7. In addition, an inflow promotion section 13 extending along the inner wall of the main channel 1 is arranged on the upstream side of the flow direction of the downstream opening 7, making it easier for the fluid to flow from the main channel 1 to the secondary channel 8. The height h of the secondary channel 8 is smaller than the height H of the main channel 1 (h<H), so that the turbulence in the secondary channel 8 is smaller than that in the main channel 1. In addition, corners of the secondary channel 8 and the inflow promotion section 13 are rounded to smooth the flow of the fluid.

Next, the operation of the physical quantity measuring device 20 of the present invention will be described.

The fluid to be measured flowing through the main flow passage 1 flows in from the inlet 2 as shown by the white arrow in Fig. 1, and when the flow F1 from the inlet 4 reaches the first receding wall 5 where the cross section suddenly expands, it forms a low-pressure region B, which is a low-pressure vortex region. Due to the negative pressure of this low-pressure region B, the flow F1 forms a flow that reattaches to the wall surface of the first receding wall 5 due to the Coanda effect. At this time, the low-pressure region B, which has become low pressure, attracts the fluid to be measured in the sub-flow passage 8 through the upstream opening 6. On the other hand, when the flow F2 that reattaches to the wall surface of the first receding wall 5 reaches the downstream opening 7, it flows into the downstream opening 7 and supplies a stable and gentle flow to the sub-flow passage 8.

The height h of the secondary flow passage 8 is set smaller than the height H of the main flow passage 1, so the turbulence of the flow in the secondary flow passage 8 is smaller than that in the main flow passage 1. In addition, corners R (rounding) are given to bends including the upstream opening 6, downstream opening 7, and inflow promotion section 13, and the like, and a sudden change in cross-sectional area is avoided. As a result, the flow F3 in the secondary flow passage 8 is made to flow more smoothly.

Therefore, the sub-channel 8 satisfies the condition necessary for measuring the concentration of fluid components, that is, the fluid in the main channel 1 and the fluid in the sub-channel 8 flow without stagnation. Therefore, the sound speed is measured in the sub-channel 8 using a pair of ultrasonic transmitters 9 and 10, and the concentration of components contained in the fluid can be measured by a known method, together with the fluid temperature from the temperature sensor 11.

In this way, the fluid from the main flow path 1 flows into the sub-flow path 8 without stagnation, and the concentration of the fluid in the main flow path 1 is uniform and gentle, achieving a stable flow with little turbulence, thereby improving the reliability and accuracy of measurements.

(Embodiment 2)
The second embodiment will be described with reference to FIGS.
Fig. 3 is a cross-sectional view of the configuration of a physical quantity measuring device according to a second embodiment of the present invention, and Fig. 4 is a view taken along the arrow A in Fig. 3 according to the second embodiment of the present invention. Note that components having the same functions as those in the first embodiment are given the same reference numbers and detailed descriptions thereof will be omitted.

In Figures 3 and 4, a second setback wall 14 is also disposed on the opposing long side 1c opposite the long side 1a on which the first setback wall 5 is provided, by setting back a portion of the long side 1c outward from the main flow path 1 by a setback length E. Here, the setback length D of the first setback wall 5 relative to the inlet 4 is set to be smaller than the setback length E of the second setback wall 14 (D<E).

Next, the operation of the physical quantity measuring device 30 of the present invention will be described.
The fluid to be measured flowing through the main flow passage 1 forms a low-pressure region G, which is a low-pressure vortex region, upstream of the second receding wall 14 on the second receding wall 14 side as well as on the first receding wall 5 side.

In the second embodiment, the first receding wall 5 and the second receding wall 14 cause the cross section to expand rapidly in the vertical direction in FIG. 5, so the flow flowing out from the downstream end of the inlet section 4 becomes a free jet, creating conditions that make the flow prone to deflection.

However, here, the retreat length D of the first retreat wall 5 and the retreat length E of the second retreat wall 14 are different sizes, and the retreat length D of the first retreat wall 5 is set to be smaller than the retreat length E of the second retreat wall 14 (D<E). This causes a difference in pressure in the low pressure region B, which is a low pressure vortex region, and the low pressure region B on the first retreat wall 5 side has a lower pressure than the low pressure region G on the second retreat wall 14 side.

Therefore, the free jet flowing out from the downstream end of the inlet section 4 is more strongly affected by the Coanda effect on the side of the first receding wall 5, which has a smaller retreat length, and adheres to the first receding wall 5 more reliably.

In this way, by forming a flow F1 that reliably adheres to the negative pressure effect of the low pressure area B, a stable and gentle flow is more reliably formed in the secondary flow path 8.

In this way, by receding both walls at the downstream end of the inlet section 4, a state is created in which flow deflection is more likely to occur, and the Coanda effect is more reliably generated on the side with the smaller receding distance, which more reliably supplies a gentle and stable flow to the secondary flow path 8, improving the measurement accuracy and reliability of measuring the concentration of components contained in the fluid.

(Embodiment 3)
The third embodiment will be described with reference to FIG.
5 is a cross-sectional view of the configuration of a physical quantity measuring device according to a third embodiment of the present invention. Note that components having the same functions as those in the first and second embodiments are given the same reference numbers and detailed descriptions thereof will be omitted.

In FIG. 5, similar to that shown in FIG. 4 of the second embodiment, in the third embodiment, a second receding wall 14 is disposed on the opposing long side 1c (not shown) opposite the long side 1a (not shown) on which the first receding wall 5 is provided, by receding a portion of the long side 1c (not shown) outwardly of the main flow path 1 by a receding length K. Here, the receding length K of the second receding wall 14 relative to the inlet 4 is set to be approximately equal to the receding length D of the first receding wall 5 (K ≒ D).

An approach opening 15 is provided in the approach section 4 upstream of the second receding wall 14, and an opening 16 is provided at the upstream end of the second receding wall 14, and the approach opening 15 and opening 16 are connected by a bias flow path 17.

Next, the operation of the physical quantity measuring device 40 of the present invention will be described.

The measured fluid flowing through the main flow path 1 has a cross section that expands rapidly in the vertical direction in FIG. 5 due to the first receding wall 5 and the second receding wall 14, so the flow flowing out from the downstream end of the inlet section 4 becomes a free jet, creating conditions that make it easy for flow deflection to occur.

In the third embodiment, at the upstream end of the second receding wall 14, the bias flow F5 that flows in from the inlet opening 15 and flows through the bias flow path 17 flows in from the opening 16.

The free jet flowing out from the inlet section 4 is not only deflected by the Coanda effect on the first receding wall 5, but also the bias flow F5 flowing in from the upstream end of the second receding wall 14 acts to push the free jet upward in FIG. 5, so that the free jet adheres more firmly to the first receding wall 5, further ensuring the generation of a flow in the secondary flow passage 8.

In this way, by receding both walls at the downstream end of the inlet section 4, a state is created in which flow deflection is more likely to occur. In addition to the flow deflection of the free jet toward the first receding wall 5 due to the Coanda effect, the flow of the bias flow passage 17 strengthens the adhesion of the free jet to the first receding wall 5, further ensuring the generation of flow in the secondary flow passage 8.

In the above embodiments of the present invention, the width of the sub-channel 8 (depth direction in Figs. 1, 3, and 5) has been described as a part of the width of the long side 1a in the width W direction of the main channel 1, but it may be the entire width W direction. Also, although it has been described as a physical quantity measuring device that measures the components of a fluid, it goes without saying that it can be deployed as a flowmeter in which a flow rate measuring unit is arranged in series on the upstream or downstream side of the main channel 1, or as a flowmeter in which a flow rate measuring unit is arranged in parallel to the main channel 1 having the sub-channel 8, since it can reduce not only the pressure loss in the main channel 1 but also reduce and stabilize the turbulence of the flow in the main channel 1.

As described above, the physical quantity measuring device of the present invention can provide a measuring device that supplies a stable flow to the secondary flow path and has a configuration with little pressure loss in the main flow path, and it is also possible to stabilize the flow in the main flow path, so that it is not only a measuring device for the components of the fluid, but also a flow meter with high measurement accuracy and versatility can be realized by incorporating a flow rate measuring unit.

REFERENCE SIGNS LIST 1 Main flow path 2 Inlet 3 Outlet 4 Approach section 5 First receding wall 6 Upstream opening 7 Downstream opening 8 Sub-flow path 9, 10 Ultrasonic transmitter/receiver 11 Temperature sensor 12 Signal processing section 13 Inflow promotion section 14 Second receding wall 15 Approach opening 16 Opening 17 Bias flow path 20, 30, 40 Physical quantity measuring device

Claims (3)

a main flow path having a rectangular cross section through which a fluid to be measured flows;
an inlet portion formed by a part of the main flow path;
a first receding wall formed by receding a long side of the main flow passage having a rectangular cross section outward downstream of the inlet portion;
an upstream opening provided on the upstream side of the first receding wall;
a downstream opening provided on a downstream side of the first receding wall;
a sub-flow passage provided outside the first receding wall and connecting the upstream opening and the downstream opening;
A pair of ultrasonic transducers disposed in the sub-channel;
A temperature sensor that detects the temperature of the fluid to be measured;
a signal processing unit that receives signals from the pair of ultrasonic transmitters and receivers and a signal from the temperature sensor and determines the component concentration of the fluid,
The recessed length of the first recessed wall is configured so that a low pressure region formed by the Coanda effect of the fluid flowing through the main flow path induces a flow from the downstream opening,
The height of the sub-channel is smaller than the height of the main channel ,
A physical quantity measuring device , wherein a width of the sub-channel along a direction perpendicular to both the direction in which the fluid to be measured flows and the height direction is smaller than a width of the main channel . a main flow path having a rectangular cross section through which a fluid to be measured flows;
an inlet portion formed by a part of the main flow path;
a first receding wall formed by receding a long side of the main flow passage having a rectangular cross section outward downstream of the inlet portion;
an upstream opening provided on the upstream side of the first receding wall;
a downstream opening provided on a downstream side of the first receding wall;
a sub-flow passage provided outside the first receding wall and connecting the upstream opening and the downstream opening;
A pair of ultrasonic transducers disposed in the sub-channel;
A temperature sensor that detects the temperature of the fluid to be measured;
a signal processing unit that receives signals from the pair of ultrasonic transmitters and receivers and a signal from the temperature sensor and determines the component concentration of the fluid,
The recessed length of the first recessed wall is configured so that a low pressure region formed by the Coanda effect of the fluid flowing through the main flow path induces a flow from the downstream opening,
a second receding wall is formed by receding a long side opposite to the first receding wall outwardly of the main flow path, and a receding length of the first receding wall is made smaller than a receding length of the second receding wall. a main flow path having a rectangular cross section through which a fluid to be measured flows;
an inlet portion formed by a part of the main flow path;
a first receding wall formed by receding a long side of the main flow passage having a rectangular cross section outward downstream of the inlet portion;
an upstream opening provided on the upstream side of the first receding wall;
a downstream opening provided on a downstream side of the first receding wall;
a sub-flow passage provided outside the first receding wall and connecting the upstream opening and the downstream opening;
A pair of ultrasonic transducers disposed in the sub-channel;
A temperature sensor that detects the temperature of the fluid to be measured;
a signal processing unit that receives signals from the pair of ultrasonic transmitters and receivers and a signal from the temperature sensor and determines the component concentration of the fluid,
The recessed length of the first recessed wall is configured so that a low pressure region formed by the Coanda effect of the fluid flowing through the main flow path induces a flow from the downstream opening,
a second receding wall is formed by receding a long side opposite to the first receding wall outwardly of the main flow path, and a bias flow path is provided on the upstream side of the second receding wall, connecting an approach opening provided in the approach section and an opening provided at the upstream end of the second receding wall.