JP5107209B2 - Air flow meter and wind speed sensor - Google Patents

Description

  The present invention is for measuring the flow rate of a gas such as air flowing in a duct, and includes a pitot tube for detecting the total pressure in the duct and a pitot tube for detecting the static pressure in the duct. The present invention relates to a differential pressure type air flow meter and a wind speed sensor.

  2. Description of the Related Art Conventionally, as an anemometer having a pitot tube for detecting the total pressure in the duct and a pitot tube for detecting the static pressure in the duct, an air flow meter having a wind speed sensor configured as shown in FIG. 19 is known. (For example, Non-Patent Document 1). That is, the wind speed sensor shown in FIG. 19 is installed at the air discharge port or the air suction port of the duct at the time of measuring the air volume, and the first hollow member 100 disposed in the upper part of the central part and the lower part of the central part. Of the first main pitot tube 104, four first main pitot tubes 104 radially disposed around the first hollow member 100, A first sub-Pitot tube 106 and a second hollow member 102 that are communicated across the first main Pitot tube 104 at positions closer to the periphery than the center position in the axial direction are separated from the first hollow member 100. Four second main pitot tubes 108 that extend radially from the center and are disposed at positions facing the first main pitot tubes 104, and the axial center positions of the respective second main pitot tubes 108 The second position at a position near the periphery away from the second hollow member 102 Communicates intersects the pitot tube 108, in which is composed of the second sub pitot tube 110. disposed at a position facing the first sub pitot tube 106.

  Here, the first main Pitot tube 104 and the first sub Pitot tube 106 are for detecting the total pressure in the duct, and a plurality of total pressures (not shown) are shown on the upper surface side of the drawing, which is the upstream side of the gas. Holes are formed at predetermined intervals along the axial direction. Further, the second main Pitot tube 108 and the second sub Pitot tube 110 are for detecting static pressure in the duct, and a plurality of static pressure holes (not shown) are formed on the lower surface side of the figure, which is the downstream side of the gas. Are formed at predetermined intervals along the axial direction.

The wind speed sensor configured as described above was obtained by the total pressure obtained by the first main Pitot tube 104 and the first sub-Pitot tube 106, and by the second main Pitot tube 108 and the second sub-Pitot tube 110. A differential pressure gauge for obtaining a dynamic pressure from the static pressure is connected to the first hollow member 100 and the second hollow member 102 so as to constitute an air flow meter.
Published by Dalton Co., Ltd. (April 2006), Model 8375 Micromanometer Anemometer, Model8710 Micromanometer Instruction Manual

  In the above-described conventional anemometer, the first sub-Pitot tube 106 communicates with the first main Pitot tube 104 constituting the wind speed sensor while crossing the second main Pitot tube 108 constituting the wind speed sensor. Since the two sub-Pitot tubes 110 are in communication with each other, there is a problem that the assembly structure becomes complicated and the manufacturing process becomes complicated.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an air flow meter and a wind speed sensor that can be easily manufactured by simplifying the assembly structure of the Pitot tube.

  In order to achieve the above object, the invention of claim 1 is an air flow meter for measuring a flow rate of a gas flowing in a duct, and is a first hollow member disposed in a central portion of a space surrounded by a frame. And a second hollow member disposed in the center of the space and coaxially disposed in the gas flow direction with respect to the first hollow member, and a total pressure in the duct is detected. One end communicates with the first hollow member and the other end is radially arranged to extend toward the frame, and a plurality of total pressures are formed on the upstream surface of the gas. A plurality of first Pitot tubes having holes formed at predetermined intervals along the axial direction, and for detecting static pressure in the duct, with one end communicating with the second hollow member; , The other end is radially arranged so as to extend toward the frame, and a plurality of the gas is disposed on the downstream surface of the gas. A plurality of second Pitot tubes which are formed with static pressure holes at predetermined intervals along the axial direction, and which form a pair with the first Pitot tube, and first and second Pitot tubes which form a pair with the space A plurality of partition plates disposed between the frame body and the first and second hollow members, and communicated with the first hollow member and the second hollow member. And a differential pressure measuring unit for obtaining a dynamic pressure from a total pressure obtained by the first Pitot tube and a static pressure obtained by the second Pitot tube.

  The invention according to claim 2 relates to the apparatus according to claim 1, wherein the air volume calculation unit for obtaining the air volume in the duct based on the dynamic pressure obtained from the differential pressure measurement unit, and the air volume obtained by the air volume calculation unit An air volume display unit for displaying is provided.

  According to a third aspect of the present invention, in the first or second aspect, the plurality of total pressure holes formed in the first Pitot tube have a circumferential space plane surrounding the first hollow member. One pitot tube is formed for each equal area divided to have an equal area in the radial direction, and a plurality of static pressure holes formed in the second pitot tube include the second It is characterized in that one pitot tube is formed for each equal area obtained by dividing a circumferential space plane surrounding the periphery of the hollow member so as to have an equal area in the radial direction.

  The invention according to claim 4 is the one according to claim 1 or 2, wherein a plurality of total pressure holes formed in the first pitot tube are formed at an equal pitch along the axial direction of each pitot tube. The plurality of static pressure holes formed in the second Pitot tube are formed at an equal pitch along the axial direction of each Pitot tube.

  A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the frame body forms a rectangular space inside the frame body.

  A sixth aspect of the invention is characterized in that, in any one of the first to fourth aspects, the frame body forms a circular space inside the frame body.

  A seventh aspect of the present invention relates to any one of the first to sixth aspects of the present invention, wherein the first Pitot tube and the second Pitot tube are respectively opposed to each other in the gas flow direction. It is characterized by being arranged as described above.

  The invention according to an eighth aspect is the invention according to the seventh aspect, wherein the first pitot tube and the second pitot tube have the same length dimension, and the first and second hollow members are intersected with each other. It is characterized by being arranged in the shape of a cross in plan view.

  The invention according to claim 9 is a wind speed sensor for measuring the flow rate of the gas flowing in the duct, the first hollow member disposed in the central portion, and the first hollow member disposed in the central portion. A second hollow member disposed coaxially in the gas flow direction with respect to one hollow member, and for detecting the total pressure in the duct, one end communicating with the first hollow member A plurality of first pressure holes formed radially at predetermined intervals along the axial direction on the upstream surface of the gas. 1 for detecting the static pressure in the duct and one end thereof communicating with the second hollow member and the other end being radially arranged so as to extend outward. A plurality of static pressure holes are formed at predetermined intervals along the axial direction on the downstream surface of the gas; A plurality of second Pitot tubes paired with the first Pitot tube, and the second Pitot tubes adjacent to each other between the first Pitot tubes arranged radially and between the first Pitot tubes arranged radially. A plurality of partition plates for partitioning the tubes are provided.

  A tenth aspect of the present invention is the one according to the ninth aspect, wherein the plurality of total pressure holes formed in the first Pitot tube radially radiate a circumferential space plane surrounding the periphery of the first hollow member. One pitot tube is formed for each equal area divided into equal areas, and a plurality of static pressure holes formed in the second pitot tube include the second hollow member. Each of the Pitot tubes is formed for each equal area obtained by dividing a circumferential space plane surrounding the periphery of the frame so as to have an equal area in the radial direction.

  The invention of claim 11 relates to claim 9, wherein the plurality of total pressure holes formed in the first pitot tube are formed at an equal pitch along the axial direction of each pitot tube. The plurality of static pressure holes formed in the second Pitot tube are formed at an equal pitch along the axial direction of each Pitot tube.

  According to the first aspect of the present invention, the space surrounded by the frame is partitioned by the partition plate for each of the first and second pitot tubes to be paired. By suppressing interference between adjacent spaces, the flow velocity of the gas in the duct (wind velocity) even if it does not have a secondary Pitot tube that crosses and communicates with the main Pitot tube as in the conventional example As a result, the assembly structure of the Pitot tube can be simplified, and an easily manufactured air flow meter can be realized.

  According to the second aspect of the present invention, the air volume calculating unit for obtaining the air volume in the duct based on the dynamic pressure obtained from the differential pressure measuring unit, and the air volume display unit for displaying the air volume obtained by the air volume calculating unit are provided. As a result, the air volume is automatically calculated and displayed, so that the air volume in the duct can be easily recognized visually.

  According to invention of Claim 3, the several total pressure hole of the 1st Pitot tube is equal area which divided the circumferential space plane surrounding the circumference | surroundings of the 1st hollow member about each Pitot tube along the radial direction And a plurality of static pressure holes of the second Pitot tube, each of which has a circumferential space plane surrounding the periphery of the second hollow member and is divided along the radial direction. By forming one for each, all the pressure holes and static pressure holes are uniformly distributed in the space, and the average flow velocity (wind speed) in the duct can be obtained accurately, resulting in excellent performance. It is possible to realize an air flow meter having

  According to the invention of claim 4, the plurality of total pressure holes of the first Pitot tube are formed at an equal pitch along the axial direction of each Pitot tube, and the plurality of static pressure holes of the second Pitot tube. However, by forming the Pitot tube at an equal pitch along the axial direction, both the total pressure holes and the static pressure holes are uniformly distributed in the space, and the average flow velocity (wind velocity) in the duct is accurately determined. As a result, an air flow meter with excellent performance can be realized.

  According to the invention of claim 5, since the frame body forms a rectangular space inside the frame body, an air flow meter suitable for a duct having a square cross section can be realized.

  According to the invention of claim 6, since the frame body forms a circular space inside the frame body, it is possible to realize an air flow meter adapted to a duct having a circular cross section.

  According to the seventh aspect of the present invention, the first and second pitot tubes are integrally formed by arranging the paired first and second pitot tubes facing each other in the gas flow direction. As a result of being able to handle and easy assembly of the Pitot tube, an easily manufactured air flow meter can be realized.

  According to the eighth aspect of the present invention, the first and second pitot tubes have the same length dimension and are arranged in a cross shape in plan view with the first and second hollow members as intersections. Therefore, without changing the assembly structure of the Pitot tube, a duct having a quadrangular cross section and a cross section having a circular shape can be obtained by properly using a frame body that forms a square space and a circular space. As a result of being able to be adapted to both of the ducts having, an air flow meter with high versatility for assembly can be realized.

  According to the ninth aspect of the present invention, since the adjacent pitot tubes are partitioned by the partition plate for each pair of the first and second pitot tubes, the adjacent first and second pitot tubes are present. By suppressing interference between spaces, the flow velocity (wind velocity) of the gas in the duct can be accurately adjusted even if it does not have a secondary Pitot tube that crosses and communicates with the main Pitot tube as in the conventional example. As a result, the assembly structure of the pitot tube is simplified, and an easily manufactured wind speed sensor can be realized.

  According to the invention of claim 10, the plurality of total pressure holes of the first Pitot tube are equal areas in which a circumferential space plane surrounding the periphery of the first hollow member is divided along the radial direction for each Pitot tube. And a plurality of static pressure holes of the second Pitot tube, each of which has a circumferential space plane surrounding the periphery of the second hollow member and is divided along the radial direction. By forming one for each, all the pressure holes and static pressure holes are uniformly distributed in the space, and the average flow velocity (wind speed) in the duct can be obtained accurately, resulting in excellent performance. Can be realized.

  According to the invention of claim 11, the plurality of total pressure holes of the first Pitot tube are formed at an equal pitch along the axial direction of each Pitot tube, and the plurality of static pressure holes of the second Pitot tube. However, by forming the Pitot tube at an equal pitch along the axial direction, both the total pressure holes and the static pressure holes are uniformly distributed in the space, and the average flow velocity (wind velocity) in the duct is accurately determined. As a result, a wind speed sensor having excellent performance can be realized.

  FIG. 1 is an external view schematically showing a differential pressure type air flow meter according to the first embodiment of the present invention with the internal configuration omitted, and FIG. 2 schematically shows a functional configuration of the air flow meter. It is a block diagram. In these drawings, the anemometer 10 is adapted to a duct having a quadrangular cross section in a direction perpendicular to the flow direction of gas such as air, and the wind speed (flow velocity) of the gas such as air flowing in the duct. A wind speed sensor (flow velocity sensor) 12 for detecting the air flow, a flow rate in the duct based on the wind speed of the gas obtained by the wind speed sensor 12, an air volume processing unit 14 attached to the wind speed sensor 12, An air volume obtained by the air volume processing unit 14 is displayed, and an air volume display unit 16 attached to the wind speed sensor 12 and a pair of grips 18 attached to the wind speed sensor 12 are provided.

  As shown in FIG. 3, the wind speed sensor 12 is positioned at a central portion of a frame body 24 having a square shape in plan view formed of a metal material such as SUS and an inner rectangular space surrounded by the frame body 24. And a rectangular tube-shaped first hollow member that is disposed on the upstream side in the gas flow direction indicated by the arrow W (upper stage in the drawing) and that constitutes a total pressure header made of a metal material such as SUS. 26 and a central portion of the inner rectangular space surrounded by the frame body 24, and is coaxial with the first hollow member 26 on the downstream side (lower stage in the figure) in the gas flow direction indicated by the arrow W. And a second hollow member 28 having a rectangular tube shape and constituting a static pressure header made of a metal material such as SUS.

  The wind speed sensor 12 is for detecting the total pressure in the duct. One end of each of the wind speed sensors 12 is connected to the first hollow member 26 and the other end is connected to the inner corner of the frame body 24. Four circular cylindrical Pitot tubes 30 that are supported and arranged radially and formed of a metal material such as SUS, and for detecting the static pressure in the duct, each of which has a second end. The other end is supported by the inner corner of the frame body 24 and arranged radially, and the arrow W is formed so as to form a pair with the first Pitot tube 30. The frame body 24 is surrounded by four round cylindrical second Pitot tubes 32 that are arranged to face each other in the gas flow direction (vertical direction in the figure) and are formed of a metal material such as SUS. The first Pitot tube 30 and the second The toe pipe 32 is partitioned for each frame, and is disposed between the frame body 24 and the first and second hollow members 26 and 28 and supported by the frame body 24 and the first and second hollow members 26 and 28. And four partition plates 34 formed of a metal material such as SUS.

  Here, in the present embodiment, the first hollow member 26 and the second hollow member 28 are partitioned into two spaces in the axial direction by an intermediate partition plate at an internal intermediate position of one rectangular tube member, while both opening surfaces are provided. The first hollow member 26 has a cylindrical connection port 38 communicating with the internal space, and the second hollow member 28 communicates with the internal space. A cylindrical connection port 40 is formed.

  Further, as shown in FIG. 4, the first Pitot tube 30 has a plurality of total pressure holes 42 each having small holes along the axial direction on the upstream surface in the gas flow direction indicated by the arrow W in FIG. Formed at predetermined intervals. Further, as shown in FIG. 5, the second Pitot tube 32 has a plurality of static pressure holes 44 each having a small hole along the axial direction on the downstream surface of the gas flow direction indicated by the arrow W in FIG. Formed at predetermined intervals.

  In other words, in the present embodiment, the plurality of total pressure holes 42 radiate a rectangular space plane in the circumferential direction that surrounds the periphery of the first hollow member 26 as schematically shown only in the total pressure holes 42 in FIG. One for each Pitot tube 30 is formed for each equal area (S1, S2, S3,..., Sn) divided to have equal areas in the direction. As a result, since there are four first Pitot tubes 30, there are four total pressure holes 42 for each equal area (S1, S2, S3,..., Sn).

  Further, the plurality of static pressure holes 44, as schematically shown only in the static pressure holes 44 in FIG. 7, have a circumferential square space plane surrounding the second hollow member 28 with an equal area in the radial direction. One is formed for each Pitot tube 32 for each of the equal areas (S1, S2, S3,..., Sn) divided in such a manner. Thereby, since there are four second Pitot tubes 32, four static pressure holes 44 exist for each equal area (S1, S2, S3,..., Sn).

  In the present embodiment, the four first Pitot tubes 30 and the four second Pitot tubes 32 have the same length, and as is apparent from the drawing, the first hollow member. 26 and the second hollow member 28 are arranged so as to have a cross shape in plan view.

  The air volume processing unit 14 is attached to the outer peripheral surface of the frame body 24, and is piped to the connection port 38 of the first hollow member 26 and the connection port 40 of the second hollow member 28. A differential pressure measuring unit that is connected in communication with the hollow member 26 and the second hollow member 28 and obtains a dynamic pressure from the total pressure obtained by the first Pitot tube 30 and the static pressure obtained by the second Pitot tube 32. (Differential pressure gauge) 20 and an air volume calculation unit 22 configured by a microcomputer or the like that calculates the air volume in the duct based on the dynamic pressure obtained from the differential pressure measurement unit 20. Based on the dynamic pressure obtained from the differential pressure measurement unit 20, the air volume calculation unit 22 stores a known air volume calculation formula including a known cross-sectional area of the duct in the memory of the microcomputer. Based on this, the air volume in the duct is calculated.

  The air volume display unit 16 is attached to the outer peripheral surface of the frame 24 integrally with the air volume processing unit 14 and is configured by a liquid crystal display or the like. The pair of grips 18 for gripping are attached to both sides of the air volume processing unit 14 and the air volume display unit 16 on the outer peripheral surface of the frame body 24.

  The anemometer 10 configured as described above is attached to an air discharge port or an air intake port of a duct via a wind collecting hood by holding a pair of handles 18 or the like, and an unillustrated power switch or operation switch is provided. By operating and operating the air volume processing unit 14 and the air volume display unit 16, the differential pressure measuring unit 20 obtains the dynamic pressure from the total pressure and the static pressure detected by the wind speed sensor 12, and based on this dynamic pressure. The air volume calculation unit 22 calculates the air volume in the duct and displays it on the air volume display unit 16.

  Here, Table 1 shows experimental results for confirming the performance of the anemometer 10 according to the first embodiment in comparison with wind tunnel experimental values serving as reference values. The airflow meters A and B in Table 1 are those of the present embodiment having the partition plate 34, and the airflow meter C is for comparison with that of the present embodiment, and among the constituent members of the wind speed sensor 12 All the partition plates 34 are removed.

  In addition, each structural member except the partition plate 34 of the airflow meters A, B, and C has the following dimensions in this embodiment. That is, in each of the anemometers A, B, and C, the frame body 24 is composed of a plate member having a length of 200 mm in the gas flow direction (arrow W in FIG. 3), and the first and second hollow members 26, The rectangular tube member which integrally forms 28 is a square pipe having a 14 mm square, a wall thickness of 1.5 mm, and a length of 42 mm. The first and second pitot tubes 30 and 32 are made of round pipes having a diameter of 10 mm and a thickness of 1 mm, and the lengths of the portions located outside the first and second hollow members 26 and 28 are each 194 mm. It is set to become. The total pressure hole 42 of the first Pitot tube 30 and the static pressure hole 44 of the second Pitot tube 32 are each formed as a 1 mmφ through-hole, and 32 pieces are formed for each of the Pitot tubes 30 and 32. . The paired first Pitot tube 30 and second Pitot tube 32 are arranged to face each other so that the distance between the central axes is 20 mm.

  And the partition plate 34 of the anemometer A is set to a length of 150 mm in the gas flow direction (arrow W in FIG. 3), and each half (75 mm) is located on each hollow member 26, 28 side. It is arranged like this. The partition plate 34 of the anemometer B is set so that the length dimension in the gas flow direction (arrow W in FIG. 3) is set to 42 mm, and each half (21 mm) is positioned on the side of each hollow member 26, 28. It is arranged. Each of these air flow meters is attached to the air outlet of the duct via a wind collecting hood so that the gas flow direction is directed in the direction of arrow W in FIG.

  Here, since the first Pitot tube 30 is located upstream in the gas flow direction and the second Pitot tube 32 is located downstream in the gas flow direction, the second Pitot tube 32 is located. Karman vortex is generated on the downstream side. In the calculation, as shown in FIG. 8, the Karman vortex has a first Karman vortex center generated at a position 51 mm away from the axial center of the second Pitot tube 32, and downstream of the first Karman vortex. The vortex centers of the second and third Karman vortices are sequentially generated at the same distance on the side. For this reason, the anemometer A has an end on the downstream side of the partition plate 34 having an overall length of 150 mm (half is 75 mm) from the vortex center of the first Karman vortex generated immediately after the second Pitot tube 32. In the anemometer B, the downstream end of the partition plate 34 having an overall length of 42 mm (half is 21 mm) is generated immediately after the second Pitot tube 32. It is located upstream from the center of the Karman vortex.

  In Table 1, wind speed levels 1 to 13 indicate that the wind speed increases as the level value increases. The numerical values described in the passing wind speed column are those detected by the wind speed sensor 12, and the wind tunnel experimental comparison value indicates the ratio of the air volume obtained by each air flow meter to the wind tunnel experimental value. The wind tunnel experiment comparison values in Table 1 are shown in a graph in FIG.

  As is apparent from the experimental results shown in Table 1 and FIG. 9, the air flow meter C having no partition plate 34 has a large difference from the wind tunnel experimental value as a whole (that is, the wind tunnel experimental contrast value is small). There is a tendency that the difference from the wind tunnel experiment value becomes larger as the air volume becomes lower (that is, the wind tunnel experiment comparison value becomes smaller). On the other hand, the anemometers A and B in the present embodiment having the partition plate 34 are closer to the wind tunnel experimental values than the anemometer C not having the partition plate 34 (that is, the wind tunnel experiment contrast value is increased). In particular, in the air flow meter A, the wind tunnel experimental value does not decrease even in the low air flow region, and has excellent performance in a wide air flow region.

  The performance of the anemometers A and B in the present embodiment having the partition plate 34 is excellent in the first and second Pitot tubes 30 and 32 in which the space surrounded by the frame body 24 is a pair. It is presumed that the partitioning by the partition plate 34 suppresses the interference of the gas flow between adjacent spaces where the paired first and second pitot tubes 30 and 32 exist. In particular, in the anemometer A in which the downstream end portion of the partition plate 34 is located downstream of the vortex center of the first Karman vortex generated immediately after the second Pitot tube 30, it is caused by the Karman vortex. It is estimated that excellent performance is exhibited in a wide air volume range by effectively suppressing interference.

  For this reason, since the wind speed of the gas in a duct can be calculated | required correctly even if it does not have a sub Pitot tube like a prior art example, the assembly structure of the 1st, 2nd Pitot tubes 30 and 32 is simplified. Thus, the anemometer 10 including the wind speed sensor 12 that is easy to manufacture can be realized. As is apparent from the experimental results of the air flow meter A, the partition plate 34 has an end portion on the downstream side of the second Pitot tube 32 (if the first Pitot tube 30 is located on the downstream side, An air flow meter provided with an air velocity sensor 12 having superior performance in a wide air flow range when set to a size located downstream of the vortex center of the Karman vortex generated immediately after one Pitot tube 30) 10 can be realized.

  In this embodiment, the first Pitot tube 30 constituting the wind speed sensor 12 is used for detecting the total pressure, and the second Pitot tube 32 is used for detecting the static pressure. However, the first Pitot tube 30 may be for detecting static pressure, and the second Pitot tube 32 may be for detecting total pressure.

  That is, when the illustrated upper surface side of the wind speed sensor 12 having the configuration shown in FIG. 3 is attached to the air discharge port of the duct via the air collecting hood, the flow direction of the gas such as air becomes the direction of the arrow W. The first Pitot tube 30 detects the total pressure, and the second Pitot tube 32 detects the static pressure. On the other hand, when the upper surface side of the wind speed sensor 12 having the configuration shown in FIG. 3 is attached to the air intake port of the duct via the air collecting hood, the flow direction of gas such as air is opposite to the arrow W. Therefore, the first Pitot tube 30 detects the static pressure, and the second Pitot tube 32 detects the total pressure.

  FIG. 10 is an external view schematically showing a differential pressure type air flow meter according to the second embodiment of the present invention with the internal configuration omitted, and FIG. 11 schematically shows a functional configuration of the air flow meter. It is a block diagram. The anemometer 10 in the second embodiment is suitable for a duct having a circular cross section in a direction orthogonal to the flow direction of a gas such as air. That is, it differs from that of the first embodiment in that the wind speed sensor 12 has a circular shape in plan view, and other configurations are basically different from those of the first embodiment. Since they are the same, the same constituent members are given the same reference numerals, and detailed description thereof is omitted.

  In the anemometer 10 according to the second embodiment, since the wind speed sensor 12 is formed in a circular shape in a plan view, as shown in FIG. 12, the frame body 24 forms a circular space on the inner side in a plan view circle. It has the same shape as that of the first embodiment except that the partition plate 34 is longer than that of the first embodiment. That is, the air volume processing unit 14, the air volume display unit 16, and the pair of handles 18 are attached to the outer peripheral surface of the circular frame body 24. Further, the first Pitot tube 30 and the second Pitot tube 32 have the same length, respectively, and have a cross-sectional shape in plan view with the first hollow member 26 and the second hollow member 28 as intersections. Since it is arrange | positioned so that it may become, the thing of 1st Embodiment can be shared.

  Since the space formed by the frame body 24 has a circular shape, the total pressure holes 42 of the first Pitot tube are first, first and second as schematically shown in FIG. One circular space plane in the circumferential direction surrounding the periphery of the two hollow members 26 and 28 is formed for each equal area divided into equal areas in the radial direction. Further, the static pressure hole 44 of the second Pitot tube has a radial circular space plane surrounding the periphery of the second hollow member 28 in a radial direction, as schematically shown only in the static pressure hole 44 in FIG. One pitot tube 32 is formed for each equal area that is divided into equal areas.

  The air flow meter 10 according to the second embodiment configured as described above is used as an air discharge port or an air intake port of a duct by gripping a pair of handles 18 as in the case of the first embodiment. The air flow processing unit 14 and the air flow display unit 16 are driven by operating a power switch or an operation switch (not shown) attached via a wind collecting hood, so that the total pressure and static pressure detected by the wind speed sensor 12 can be detected. The dynamic pressure is obtained by the differential pressure measuring unit 20, and the air volume in the duct is calculated by the air volume calculating unit 22 based on the dynamic pressure and displayed on the air volume display unit 16.

  Here, Table 2 shows experimental results for confirming the performance of the air flow meter 10 according to the second embodiment in comparison with wind tunnel experimental values serving as reference values. The airflow meters D and E in Table 2 are those of the present embodiment having the partition plate 34, and the airflow meter F is for comparison with the present embodiment, and among the constituent members of the wind speed sensor 12 All the partition plates 34 are removed.

  The dimensions of the constituent members excluding the partition plates 34 of the airflow meters D, E, and F are all the same as the previous airflow meters A, B, and C except that the shape of the frame body 24 is different. The partition plate 34 of the anemometer D is set so that the length of the gas flow direction (arrow W in FIG. 3) is 150 mm, and each half (75 mm) is positioned on the side of each hollow member 26, 28. It is arranged. The partition plate 34 of the anemometer E is set so that the length dimension in the gas flow direction (arrow W in FIG. 3) is set to 42 mm, and each half (21 mm) is positioned on the side of each hollow member 26, 28. It is arranged. Each of these air flow meters is attached to the air outlet of the duct via a wind collecting hood so that the gas flow direction is directed in the direction of arrow W in FIG. The Karman vortex is formed at the same position as in the previous embodiment.

  In Table 2, wind speed levels 1 to 13 indicate that, as in Table 1, the wind speed increases as the level value increases. The numerical values described in the passing wind speed column are those detected by the wind speed sensor 12, and the wind tunnel experimental comparison value indicates the ratio of the air volume obtained by each air flow meter to the wind tunnel experimental value. The wind tunnel experiment comparison values in Table 2 are shown in a graph in FIG.

  As apparent from the experimental results shown in Table 2 and FIG. 15, the air flow meter F having no partition plate 34 has a large difference from the wind tunnel experimental value as a whole (that is, the wind tunnel experimental contrast value is small). There is a tendency that the difference from the wind tunnel experiment value becomes larger as the air volume becomes lower (that is, the wind tunnel experiment comparison value becomes smaller). On the other hand, the airflow meters D and E (particularly the airflow meter D) in the present embodiment having the partition plate 34 are closer to the wind tunnel experimental values than the air flow meter F not having the partition plate 34 (that is, the wind tunnel). The experimental contrast value is large), and it has excellent performance in a wide air volume range.

  Thus, the performance of the anemometers D and E (particularly the anemometer D) in the present embodiment having the partition plate 34 is excellent in the first and second pairs of spaces surrounded by the frame body 24. Since each of the Pitot tubes 30 and 32 is partitioned by the partition plate 34, the interference of the gas flow between the adjacent spaces where the paired first and second Pitot tubes 30 and 32 exist is suppressed. I guess that. In particular, in the anemometer D in which the downstream end portion of the partition plate 34 is located downstream of the vortex center of the first Karman vortex generated immediately after the second Pitot tube 30, it is caused by the Karman vortex. It is estimated that excellent performance is exhibited in a wide air volume range by effectively suppressing interference.

  For this reason, since the wind speed of the gas in a duct can be calculated | required correctly even if it does not have a sub Pitot tube like a prior art example, the assembly structure of the 1st, 2nd Pitot tubes 30 and 32 is simplified. Thus, the anemometer 10 including the wind speed sensor 12 that is easy to manufacture can be realized. As is clear from the experiment results of the air flow meter D, the partition plate 34 has a downstream end portion of the second Pitot tube 32 (if the first Pitot tube 30 is positioned downstream, An air flow meter provided with an air velocity sensor 12 having superior performance in a wide air flow range when set to a size located downstream of the vortex center of the Karman vortex generated immediately after one Pitot tube 30) 10 can be realized.

  In addition, this invention is not limited to the thing of the said embodiment, The various deformation | transformation aspects as described below can be employ | adopted as needed.

  (1) In the above embodiment, the frame 24, the first and second hollow members 26 and 28, the first and second pitot tubes 30 and 32, and the like are formed of a metal material such as SUS. However, it is not limited to this. For example, it is also possible to comprise other hard materials such as hard resin such as epoxy resin and ceramic.

  (2) In the above embodiment, four first and second pitot tubes 30 and 32 are used, but the present invention is not limited to this. For example, the number of the first and second Pitot tubes 30 and 32 may be three, or may be five or more. These first and second Pitot tubes 30 and 32 are preferably configured such that each Pitot tube is radially arranged at an equal angle in the same plane.

  (3) In the above embodiment, the first and second pitot tubes 30 and 32 that are paired are disposed so as to face each other in the gas flow direction, but the present invention is not limited to this. For example, the first and second Pitot tubes 30 and 32 that form a pair may be arranged so as to be shifted from each other in a plane direction by a predetermined angle.

  (4) In the above-described embodiment, the anemometer 10 includes the differential pressure measuring unit 20 for obtaining the dynamic pressure from the total pressure and the static pressure obtained from the first and second pitot tubes 30 and 32 constituting the wind speed sensor 12, Although it comprises the calculation part 22, the air volume display part 16, etc., it is not restricted to this. For example, after obtaining the dynamic pressure from the total pressure and static pressure obtained from the first and second Pitot tubes 30 and 32, the air volume can be calculated manually. As described above, when the air volume is calculated manually, the air volume meter 10 may include only the differential pressure measuring unit 20.

  (5) In the above embodiment, in the wind speed sensor 12 shown in FIG. 3 provided with the frame body 24 having a square shape in plan view, the first and second pitot tubes 30 and 32 are supported by the inner corner portion of the frame body 24. Thus, the partition plate 34 is supported by the opposing sides of the frame body 24, but is not limited thereto. For example, as shown in FIG. 16, the first and second pitot tubes 30 and 32 are supported on opposite sides of the frame body 24, and the partition plate 34 is supported on the inner corner portion of the frame body 24. You can also.

  (6) In the above embodiment, the total pressure hole 42 of the first Pitot tube 30 and the static pressure hole 44 of the second Pitot tube 32 are each formed with an equal area. It is not limited. For example, the total pressure holes 42 of the first Pitot tube 30 and the static pressure holes 44 of the second Pitot tube 32 may be formed at equal pitches along the axial direction of each Pitot tube. Thus, even when the total pressure holes 42 of the first Pitot tube 30 and the static pressure holes 44 of the second Pitot tube 32 are formed at an equal pitch, the performance is the same for each equal area of the first and second embodiments. It has been experimentally confirmed that there is no difference from that in which one is formed.

  That is, among the constituent members of the air flow meter 10 according to the first embodiment shown in FIGS. 1 to 3 in which the frame body 24 has a square shape in plan view, the total pressure holes 42 and the second pressure holes 42 of the first Pitot tube 30 are included. In the case where the static pressure holes 44 of the Pitot tube 32 are formed at an equal pitch (the number of the total pressure holes 42 and the static pressure holes 44 is 32 for each of the Pitot tubes 30 and 32), the length dimension in the gas flow direction Is an air flow meter G having a 150 mm partition plate 34 attached in the same manner as the air flow meter A, and an air flow meter H having a partition plate 34 having a gas flow direction length of 42 mm attached in the same manner as the air flow meter B. Table 3 is a table similar to Table 1 and Table 2 in which all the partition plates 34 are removed is referred to as an air flow meter I, and each of the air flow meters G, H, and I is compared with wind tunnel experimental values. The wind tunnel experiment comparison values in Table 3 are shown in a graph in FIG.

  As is apparent from the experimental results shown in Table 3 and FIG. 17, the air flow meter I having no partition plate 34 has a large difference from the wind tunnel experimental value as a whole (that is, the wind tunnel experimental contrast value is small). There is a tendency that the difference from the wind tunnel experiment value becomes larger as the air volume becomes lower (that is, the wind tunnel experiment comparison value becomes smaller). On the other hand, the air flow meters G and H in the present embodiment having the partition plate 34 generally approach the wind tunnel experimental value as compared with the air flow meter I not having the partition plate 34 (that is, the wind tunnel experimental contrast value is The wind tunnel experimental value does not decrease even in the low air volume region, and has excellent performance in a wide air flow region. Thus, it is estimated that it is based on the reason similar to the reason mentioned previously that the performance of the anemometers G and H which have the partition plate 34 is excellent.

  Further, among the constituent members of the anemometer 10 according to the second embodiment shown in FIGS. 10 to 12 in which the frame body 24 has a circular shape in plan view, the total pressure hole 42 and the second pressure hole 42 of the first Pitot tube 30. In the case where the static pressure holes 44 of the Pitot tube 32 are formed at an equal pitch (the number of the total pressure holes 42 and the static pressure holes 44 is 32 for each of the Pitot tubes 30 and 32), the length dimension in the gas flow direction Is an air flow meter J having a partition plate 34 of 150 mm attached in the same manner as the air flow meter D, and an air flow meter K having a partition plate 34 having a length in the gas flow direction of 42 mm attached in the same manner as the air flow meter E. Table 4 is a table similar to Table 1 and Table 2 in which all the partition plates 34 have been removed is referred to as an air flow meter L, and each of the air flow meters J, K, and L is compared with wind tunnel experimental values. The wind tunnel experiment comparison values in Table 4 are shown in graph form in FIG.

  As is clear from the experimental results shown in Table 4 and FIG. 18, the air flow meter L having no partition plate 34 has a large difference from the wind tunnel experimental value as a whole (that is, the wind tunnel experimental contrast value is small). There is a tendency that the difference from the wind tunnel experiment value becomes larger as the air volume becomes lower (that is, the wind tunnel experiment comparison value becomes smaller). On the other hand, the anemometers J and K in the present embodiment having the partition plate 34 are closer to the wind tunnel experimental values than the anemometer L not having the partition plate 34 (that is, the wind tunnel experiment contrast value is increased). In particular, the air flow meter J has excellent performance in a wide air flow range. Thus, it is estimated that it is based on the reason similar to the reason mentioned previously that the performance of the anemometers J and K which have the partition plate 34 is excellent.

  (7) In the above embodiment, the first and second pitot tubes 30 and 32 are supported by the frame body 24, and the partition plate 34 is connected to the frame body 24 and the first and second hollow members 26 and 28. By being supported, the anemometer 10 including the wind speed sensor 12 having excellent overall mechanical strength can be realized, but the present invention is not limited to this. For example, when the partition plate 34 is supported by the frame body 24 and the first and second hollow members 26 and 28, the first and second pitot tubes 30 and 32 are supported by the frame body 24. It can also be set as the structure without. When the first and second pitot tubes 30 and 32 are supported by the frame body 24, the partition plate 34 is not supported by the frame body 24 or the first and second hollow members 26 and 28. It can also be configured. Further, the partition plate 34 is not supported by the first and second hollow members 26, 28, but the first and second pitot tubes 30 in the vicinity of the first and second hollow members 26, 28, 32 may be supported. In any case, since the frame body 24 is provided, the frame body 24 can be gripped, so that the handleability is excellent.

  (8) In the above embodiment, the air flow meter 10 is configured by attaching the air flow processing unit 14 and the air flow display unit 16 to the frame body 24 of the wind speed sensor 12, but the present invention is not limited to this. For example, the air volume processing unit 14 and the air volume display unit 16 may be configured to be used independently of the wind speed sensor 12 without being attached to the frame 24 of the wind speed sensor 12. In such a case, the wind speed sensor 12 can be distributed to the market independently.

  Furthermore, the frame body 24 of the wind speed sensor 12 can be removed and attached to the inside of the duct, and the wind speed sensor (flow velocity sensor) 12 for measuring the flow rate of the gas flowing in the duct can be circulated in the market independently. . In this case, the wind speed sensor 12 is used, for example, by being attached to the inside of the duct, and the dimensions of the first and second pitot tubes 30 and 32 and the partition plate 34 are adapted to the inner diameter of the duct. Is done. It has been experimentally confirmed that even such a wind speed sensor 12 exhibits the same performance as the wind speed sensor 12 constituting the anemometer 10 in each of the previous embodiments.

  That is, in this case, the wind speed sensor 12 is disposed in the central portion with the first hollow member 26, and is coaxial with the first hollow member 26 in the gas flow direction. The second hollow member 28 is disposed to detect the total pressure in the duct, and one end communicates with the first hollow member 26 and the other end faces outward (duct direction). And a plurality of first Pitot tubes 30 each having a plurality of total pressure holes 42 formed on the upstream surface of the gas at predetermined intervals along the axial direction. This is for detecting the pressure, and one end is communicated with the second hollow member 28 and the other end is radially arranged so as to extend outward (in the duct direction). A plurality of static pressure holes 44 are formed at predetermined intervals along the axial direction, and the first Pitot tube 3 is formed. A plurality of second Pitot tubes 32 paired with each other, between the first Pitot tubes 30 adjacent to each other radially and between the second Pitot tubes 32 adjacent to each other arranged radially. It becomes the structure provided with the some partition plate 34 to partition.

  Even in this case, the plurality of total pressure holes 42 formed in the first Pitot tube 30 are divided so that the circumferential space plane surrounding the first hollow member 26 has an equal area in the radial direction. It is assumed that one pitot tube is formed for each equal area, and the plurality of static pressure holes 44 formed in the second pitot tube 32 are circumferential spaces surrounding the second hollow member 28. One plane may be formed for each Pitot tube for each equal area that is divided into equal areas in the radial direction, or a plurality of Pitto tubes 30 may be formed. The total pressure holes 42 are formed at an equal pitch along the axial direction of each Pitot tube, and the plurality of static pressure holes 44 formed in the second Pitot tube 32 are along the axial direction of each Pitot tube. May be formed at an equal pitch.

1 is an external view schematically showing an anemometer according to a first embodiment of the present invention. It is a block diagram which shows roughly the function structure of the anemometer shown in FIG. It is a figure which shows the structure of the wind speed sensor which comprises the anemometer shown in FIG. It is a figure which shows arrangement | positioning of all the pressure holes of the 1st Pitot tube which comprises the wind speed sensor shown in FIG. It is a figure which shows arrangement | positioning of the static pressure hole of the 2nd Pitot tube which comprises the wind speed sensor shown in FIG. It is a figure which shows typically arrangement | positioning of the total pressure hole of the 1st Pitot tube which comprises the wind speed sensor shown in FIG. It is a figure which shows typically arrangement | positioning of the static pressure hole of the 2nd Pitot tube which comprises the wind speed sensor shown in FIG. It is a schematic diagram for demonstrating the generation | occurrence | production state of a Karman vortex. It is a graph which shows the correspondence of a wind speed level and a wind tunnel experiment contrast value. It is an external view which shows roughly the anemometer which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows roughly the function structure of the anemometer shown in FIG. It is a figure which shows the structure of the wind speed sensor which comprises the anemometer shown in FIG. It is a figure which shows typically arrangement | positioning of the total pressure hole of the 1st Pitot tube which comprises the wind speed sensor shown in FIG. It is a figure which shows typically arrangement | positioning of the static pressure hole of the 2nd Pitot tube which comprises the wind speed sensor shown in FIG. It is a graph which shows the correspondence of a wind speed level and a wind tunnel experiment contrast value. It is a figure which shows another structural example of the wind speed sensor shown in FIG. It is a graph which shows the correspondence of a wind speed level and a wind tunnel experiment contrast value. It is a graph which shows the correspondence of a wind speed level and a wind tunnel experiment contrast value. It is a figure which shows the structure of the wind speed sensor used for the anemometer of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Air flow meter 12 Wind speed sensor 14 Air volume process part 16 Air volume display part 20 Differential pressure measurement part 22 Air volume calculation part 24 Frame 26 1st hollow member 28 2nd hollow member 30 1st pitot tube 32 2nd pitot tube 34 Partition plate 42 Total pressure hole 44 Static pressure hole

Claims (11)

  An anemometer for measuring the flow rate of gas flowing in the duct, the first hollow member disposed in the central portion of the space surrounded by the frame, and disposed in the central portion of the space, A second hollow member disposed coaxially in the gas flow direction with respect to the first hollow member, and for detecting the total pressure in the duct, one end of the first hollow member And the other end is radially arranged to extend toward the frame, and a plurality of pressure holes are formed at predetermined intervals along the axial direction on the upstream surface of the gas. A plurality of first Pitot tubes and one for detecting static pressure in the duct, one end communicating with the second hollow member and the other end extending radially toward the frame A plurality of static pressure holes are formed at predetermined intervals along the axial direction on the downstream surface of the gas. A plurality of second Pitot tubes paired with the first Pitot tube, and the first and second Pitot tubes paired with the space, wherein the frame and the first, second A total pressure obtained by the first Pitot tube connected to the plurality of partition plates disposed between the first hollow member and the first hollow member and the second hollow member. And a differential pressure measuring unit for obtaining a dynamic pressure from a static pressure obtained by the second Pitot tube.   An air volume calculation unit that calculates an air volume in the duct based on a dynamic pressure obtained from the differential pressure measurement unit, and an air volume display unit that displays the air volume obtained by the air volume calculation unit. Item 1. An air flow meter according to item 1.   A plurality of total pressure holes formed in the first Pitot tube are provided for each equal area obtained by dividing a circumferential space plane surrounding the first hollow member so as to have an equal area in the radial direction. One of the Pitot tubes is formed, and the plurality of static pressure holes formed in the second Pitot tube have an equal area in a radial direction on a circumferential space plane surrounding the second hollow member. The anemometer according to claim 1 or 2, wherein one pitot tube is formed for each equal area divided so as to become.   The plurality of total pressure holes formed in the first Pitot tube are formed at an equal pitch along the axial direction of each Pitot tube, and the plurality of static pressures formed in the second Pitot tube. 3. The air flow meter according to claim 1, wherein the holes are formed at an equal pitch along an axial direction of each pitot tube.   The anemometer according to any one of claims 1 to 4, wherein the frame body forms a rectangular space inside the frame body.   The anemometer according to any one of claims 1 to 4, wherein the frame body forms a circular space inside the frame body.   7. The first Pitot tube and the second Pitot tube, respectively, wherein a pair of Pitot tubes are arranged opposite to each other in the gas flow direction. An air flow meter according to any one of the above.   The first Pitot tube and the second Pitot tube have the same length and are arranged in a cross-sectional shape in plan view with the first and second hollow members as intersections. The anemometer according to claim 7, wherein:   A wind speed sensor for measuring a flow rate of a gas flowing in a duct, the first hollow member disposed in a central portion, and disposed in the central portion, the first hollow member A second hollow member arranged coaxially in the gas flow direction, and for detecting the total pressure in the duct, one end communicating with the first hollow member and the other end A plurality of first Pitot tubes which are radially arranged to extend outward and have a plurality of total pressure holes formed at predetermined intervals along the axial direction on the upstream surface of the gas; This is for detecting the static pressure in the duct. One end of the duct is communicated with the second hollow member, and the other end is radially arranged so as to extend outward. A plurality of static pressure holes are formed in the surface at predetermined intervals along the axial direction, and the first Pitot tube and A plurality of second Pitot tubes forming a plurality of spaces, and a plurality of first Pitot tubes adjacent to each other arranged radially and a plurality of second Pitot tubes arranged adjacent to each other radially. A wind speed sensor comprising a partition plate.   A plurality of total pressure holes formed in the first Pitot tube are provided for each equal area obtained by dividing a circumferential space plane surrounding the first hollow member so as to have an equal area in the radial direction. One of the Pitot tubes is formed, and the plurality of static pressure holes formed in the second Pitot tube have an equal area in a radial direction on a circumferential space plane surrounding the second hollow member. 10. The wind speed sensor according to claim 9, wherein one pitot tube is formed for each of the equal areas divided so as to be.   The plurality of total pressure holes formed in the first Pitot tube are formed at an equal pitch along the axial direction of each Pitot tube, and the plurality of static pressures formed in the second Pitot tube. The wind speed sensor according to claim 9, wherein the holes are formed at an equal pitch along an axial direction of each Pitot tube.

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