Physical Quantity Measuring Devices

Abstract

To provide a physical quantity measurement device capable of improving the measuring accuracy in a secondary flow path by supplying a stable flow to the secondary flow path without causing a pressure loss affecting the flow in a main flow path.SOLUTION: The physical quantity measurement device includes: a first retreat wall 5 that is formed by retracting a part of the long side 1a of a main flow path 1 of the rectangular cross-section outward; an upstream opening 6 formed at the upstream side of the first retreat wall 5; a downstream opening 7 formed at the downstream side of the first retreat wall 5; and a secondary flow path 8 that is formed outward of the first retreat wall 5 connecting the upstream opening 6 and the downstream opening 7. The retreat length D of the first retreat wall 5 is configured so that a low-pressure region B is formed by the Coanda effect of the fluid flowing in main flow path 1 to attract the flow from the downstream opening 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a configuration for sampling a portion of a flowing fluid to be used and measuring characteristics such as the concentration of components contained in the fluid. [Background technology]

[0002] There are applications where it is necessary to measure the concentration of a component contained in a fluid without being affected by turbulence in the fluid flowing through a flow channel.

[0003] 2. Description of the Related Art Conventionally, a known measuring device for measuring components of a fluid is an ultrasonic flowmeter having a component measuring section that samples a fluid flowing through the flow measuring section, which is provided in addition to the flow measuring section (see, for example, Patent Document 1).

[0004] FIG. 6 shows a cross-sectional view of a portion of the ultrasonic flowmeter described in Patent Document 1.

[0005] In this flow meter, measurement flow path 101 is divided into multiple layers by partition plates 102 to form multilayer flow path 103. A sub-flow path 104 for measuring the components of the fluid is provided in this multilayer flow path 103. A protrusion 105 is arranged on the inlet side of measurement flow path 101 to partially narrow the flow path cross section, and the ejector effect draws the fluid into measurement flow path 101 from opening 106 on the upstream side of multilayer flow path 103a, causing the fluid in the gas meter to flow into 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 flow path. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2018 / 185034 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional configuration, in order to exert an ejector effect that draws the fluid in the main flow passage into the sub-flow passage that measures the fluid components, the flow passage cross section must be partially narrowed, which generates pressure loss. However, if this pressure loss is reduced, there is a problem that it is not possible to obtain sufficient suction force to cause the fluid to flow into the sub-flow passage.

[0008] The present invention is devised to solve the above-mentioned problems in the conventional art, and aims to provide 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. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the physical quantity measuring device of the present invention comprises a first receding wall formed by receding outward the long side of a main flow passage having a rectangular cross section through which a fluid to be measured flows, 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 secondary flow passage connecting the upstream opening and the downstream opening provided on the outer 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 through the main flow passage induces a flow from the downstream opening, and the height of the secondary flow passage is smaller than the height of the main flow passage. The 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 the width of the main channel. This allows a stable flow to be supplied to the sub-channel, improving measurement accuracy in the sub-channel, reducing pressure loss in the main channel, and further reducing turbulence in the main channel.

[0010] Furthermore, by configuring the long side opposite the first receding wall to be recessed outwardly from the main flow path to form a second receding wall, and making the recession length of the first receding wall smaller than the recession length of the second receding wall, the walls on both sides of the inlet outlet are recessed together, making it easier for flow deflection to occur and more reliably generating the Coanda effect on the side with the smaller recession distance.

[0011] Furthermore, the long side opposite the first retreat wall is set back outward from the main passage to form a second retreat wall, and a bias passage is provided on the upstream side of the second retreat wall, connecting the inlet opening provided in the inlet section and the 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 made more reliable. Effect of the Invention

[0012] The physical quantity measuring device of the present invention is provided with a first receding wall formed by receding part of the long side of a main flow path having a rectangular cross section outward, and the receding length of this 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 and improving the measurement accuracy in the secondary flow path, as well as reducing pressure loss in the main flow path and reducing flow turbulence in the main flow path. [Brief description of the drawings]

[0013] [Figure 1] 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. [Diagram 2] FIG. 2A is a plan view of a physical quantity measuring device according to a first embodiment of the present invention; FIG. 2B is a view taken along the arrow A in FIG. [Diagram 3] 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. [Figure 4] 3 in the second embodiment of the present invention. [Diagram 5] 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. [Figure 6] Cross-sectional view showing the configuration of a conventional component measuring unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The first invention includes a main flow path having a rectangular cross section through which a fluid to be measured flows, an inlet section formed by a part of the main flow path, a first receding wall formed by receding a long side of the main flow path having a rectangular cross section outward downstream of the inlet 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 outward of the first receding wall and connecting the upstream opening and the downstream opening, a pair of ultrasonic transmitter / receivers disposed 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 such 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.

[0015] The second 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 flow path, and the retreat length of the first retreat wall is made smaller than the retreat length of the second retreat wall. By receding both walls of the inlet section outlet, a state in which flow deflection is likely to occur can be created, and the Coanda effect on the side with the smaller retreat distance can be more reliably generated.

[0016] A third invention is characterized in that a second retreat wall is formed by retreating a long side facing the first retreat wall outwardly of the main flow path, and a bias flow path 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. With this, in addition to the deflection of the free jet toward the first retreat wall due to the Coanda effect, the flow of the bias channel can strengthen the attachment of the free jet to the first retreat wall, thereby making it possible to further ensure the generation of a flow in the sub-channel.

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, in some cases, 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.

[0018] It should be noted that 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.

[0019] (Embodiment 1) The first embodiment will be described with reference to FIGS. 1 and 2. FIG.

[0020] FIG. 1 is a cross-sectional view of the configuration of a physical quantity measuring device in embodiment 1 of the present invention, FIG. 2(a) is a plan view seen from direction G in FIG. 1 in embodiment 1 of the present invention, and FIG. 2(b) is a view seen from direction A in FIG. 1.

[0021] In Figures 1 and 2, a 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 measured fluid flows is formed, and inside the sub-flow path section 22, a sub-flow path 8 communicating with the main flow path 1 is formed.

[0022] 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 part of the long side 1a outwardly of the main flow channel 1 by a receding length D is disposed on the downstream side of this approach section 4. An upstream opening 6 is provided on the upstream side of this first receding wall 5, and a downstream opening 7 is provided on the downstream side.

[0023] Outward from the main flow path 1 of the first retreat wall 5, a sub-flow path 8 with a length L connecting the upstream opening 6 and the downstream opening 7 is provided. In this sub-flow path 8, a pair of ultrasonic transceivers 9, 10 arranged opposite to the flow direction and a temperature sensor 11 for detecting the temperature of the fluid are arranged.

[0024] This pair of ultrasonic transceivers 9, 10 and the temperature sensor 11 are electrically connected to the signal processing unit 12, and this signal processing unit 12 receives the signals from this pair of ultrasonic transceivers 9, 10 and the signal from the temperature sensor 11 to measure the component concentration of the fluid to be measured.

[0025] The retreat length D of the first retreat wall 5 with respect to the run-up section 4 is configured by setting it such that the low-pressure region B formed by the Coanda effect of the fluid flowing through the main flow path 1 attracts the flow from the downstream opening 7. Further, at the downstream opening 7, an inflow promotion section 13 extending along the inner wall of the main flow path 1 is arranged on the upstream side in the flow direction to facilitate the inflow of the fluid from the main flow path 1 into the sub-flow path 8. Note that the height h of the sub-flow path 8 is made smaller than the height H of the main flow path 1 (h < H) so that the turbulence in the sub-flow path 8 is smaller than the flow in the main flow path 1. Also, the sub-flow path 8 and the inflow promotion section 13 are rounded at corners and the like so that the flow of the fluid becomes smooth.

[0026] Next, the operation of the physical quantity measuring device 20 of the present invention will be described.

[0027] The fluid to be measured flowing through the main flow path 1 flows in from the inlet 2 as shown by the white arrow in FIG. 1, and the flow F1 from the run-up section 4 forms a low-pressure region B, which is a low-pressure vortex region, when it reaches the first retreat wall 5 portion where the cross-section suddenly expands. Due to the negative pressure in this low-pressure region B, the flow F1 forms a flow that reattaches to the wall surface of the first retreat wall 5 by the Coanda effect. At this time, the low-pressure region B that has become low-pressure attracts the fluid to be measured in the sub-flow path 8 through the upstream opening 6. On the other hand, when the flow F2 reattached to the wall surface of the first retreat 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 path 8.

[0028] ​​In the sub-channel 8, since its height h is set to be smaller than the height H of the main channel 1, the flow turbulence in the sub-channel 8 is smaller than that in the main channel 1. Also, a corner R (rounding) is provided at the bending portions including the upstream opening 6, the downstream opening 7, and the inflow promoting portion 13, and the configuration is such that a sudden change in the cross-sectional area is avoided. For this reason, the flow F3 in the sub-channel 8 is made to be smoother.

[0029] Therefore, in the sub-channel 8, since the condition necessary for the concentration measurement of the fluid components, that is, the fluid in the main channel 1 and the fluid in the sub-channel 8 flow without staying, is satisfied, the speed of sound is measured using the pair of ultrasonic transceivers 9 and 10 in the sub-channel 8, and together with the temperature of the fluid from the temperature sensor 11, the concentration of the components contained in the fluid can be measured by a known method.

[0030] Thus, in the sub-channel 8, the fluid of the main channel 1 flows in without staying, and a stable flow with uniform concentration, etc., gentle and with little turbulence is realized, so that the reliability and accuracy of the measurement can be improved.

[0031] (Embodiment 2) Embodiment 2 will be described with reference to FIGS. 3 to 4. FIG. 3 is a cross-sectional configuration diagram of the physical quantity measurement device according to Embodiment 2 of the present invention, and FIG. 4 is a view taken in the direction of arrow A as seen from the direction A of FIG. 3 in Embodiment 2 of the present invention. Note that those having the same functions as in Embodiment 1 are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0032] In FIGS. 3 and 4, on the opposite long side 1c side to the long side 1a provided with the first retreat wall 5, a second retreat wall 14 formed by retreating a part of the long side 1c outward from the main channel 1 by a retreat length E is also arranged. Here, the retreat length D of the first retreat wall 5 with respect to the run-up portion 4 is set to be smaller (D < E) than the retreat length E of the second retreat wall 14.

[0033] Next, the operation of the physical quantity measurement device 30 of the present invention will be described. The fluid to be measured flowing through the main flow path 1 forms a low-pressure region G, which is a low-pressure vortex region, upstream of the second retreat wall 14, just as it does on the side of the first retreat wall 5.

[0034] In Embodiment 2, since the cross-section expands abruptly in the vertical direction in FIG. 5 due to the first retreat wall 5 and the second retreat wall 14, the flow flowing out from the downstream end of the run-up portion 4 becomes a free jet state, creating conditions where flow deflection is likely to occur.

[0035] 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, and the retreat length D of the first retreat wall 5 is set smaller than the retreat length E of the second retreat wall 14 (D < E). For this reason, a difference in pressure occurs in the low-pressure regions B and G, which are low-pressure vortex regions, and the low-pressure region B on the side of the first retreat wall 5 has a lower pressure than the low-pressure region G on the side of the second retreat wall 14.

[0036] Therefore, the free jet flowing out from the downstream end of the run-up portion 4 is strongly affected by the Coandă effect on the side of the first retreat wall 5 with the smaller retreat length and adheres more reliably to the first retreat wall 5.

[0037] By thus forming the negative pressure effect of the low-pressure region B and the flow F1 that adheres reliably, a more stable and gentle flow is more reliably formed in the sub-flow path 8.

[0038] In this way, by retreating both walls on both sides of the downstream end of the run-up portion 4 to create a state where flow deflection is likely to occur and more reliably generating the Coandă effect on the side with the smaller retreat distance, a more gentle and stable flow is more reliably supplied to the sub-flow path 8, improving the measurement accuracy of measuring the component concentration contained in the fluid and enhancing the reliability of the measurement.

[0039] (Embodiment 3) Embodiment 3 will be described with reference to FIG. 5. 5 is a cross-sectional view of the configuration of a physical quantity measuring device according to the 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.

[0040] 5, in the same manner as 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 to the long side 1a (not shown) on which the first receding wall 5 is provided, by receding a part of the long side 1c (not shown) by a receding length K toward the outside of the main flow path 1. Here, the receding length K of the second receding wall 14 with respect to the inlet portion 4 is set to be substantially equal to the receding length D of the first receding wall 5 (K ≈ D).

[0041] An inlet opening 15 is provided in the inlet portion 4 on the upstream side of this second receding wall 14, and an opening 16 is further provided at the upstream end of the second receding wall 14, and this inlet opening 15 and opening 16 are connected by a bias flow path 17.

[0042] Next, the operation of the physical quantity measuring device 40 of the present invention will be described.

[0043] The measured fluid flowing through the main flow path 1 has its cross section suddenly expanded in the vertical direction in FIG. 5 by the first receding wall 5 and the second receding wall 14, so that the flow flowing out from the downstream end of the inlet portion 4 becomes a free jet, creating conditions that make the flow prone to deflection.

[0044] In the third embodiment, at the upstream end of the second receding wall 14, a bias flow F5 that flows in from the inlet opening 15 and flows through the bias flow passage 17 flows in from the opening 16.

[0045] The free jet issuing from the inlet section 4 is not only deflected by the Coanda effect at the first receding wall 5, but also by the bias flow F5 flowing in from the upstream end of the second receding wall 14, which acts to push the free jet upward in FIG. 5, so that the free jet adheres more firmly to the first receding wall 5 and the generation of a flow in the secondary passage 8 can be made even more reliable.

[0046] In this way, by receding both walls on both sides of 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 deflection of the free jet towards the first receding wall 5 due to the Coanda effect, the flow of the bias channel 17 strengthens the adhesion of the free jet to the first receding wall 5, thereby making it possible to further ensure the generation of flow in the secondary channel 8.

[0047] 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 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 in the width W direction. Also, although the device has been described as a physical quantity measuring device that measures components of a fluid, it goes without saying that the device 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 the device can reduce pressure loss in the main channel 1 as well as reduce and stabilize turbulence in the main channel 1. [Industrial Applicability]

[0048] As described above, the physical quantity measuring device of the present invention can provide a measuring device that supplies a stable flow to the sub-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. Therefore, not only can it be used as a measuring device for measuring the components of a fluid, but it can also be provided with a flow rate measuring unit to realize a flow meter with high measurement accuracy and versatility. [Explanation of symbols]

[0049] 1 Main channel 2 entrance 3 exit 4. Run-up section 5. First Retreat Wall 6 Upstream opening 7 Downstream opening 8 Subchannel 9, 10 Ultrasonic Transducer 11 Temperature Sensor 12 Signal Processing Section 13 Inflow Promotion Department 14 Second Retreat Wall 15 Run-up opening 16 Opening 17 Bias Channel 20, 30, 40 Physical quantity measuring device

Claims

1. 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 attracts 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 a flow direction of the fluid to be measured and the height direction is smaller than a width of the main channel.

2. 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; The pair of ultrasonic transducers receive signals from the ultrasonic transducer and a temperature sensor, and the fluid A signal processing unit that determines the concentration of a component, 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 attracts 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.

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 attracts 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.

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