JP5019958B2 - Flowmeter - Google Patents

Description

  The present invention relates to a flow meter having a flow path structure that rectifies a gas for flow rate measurement.

  As shown in FIGS. 8 and 9, the flow path structure 90 used in the conventional flow meter is parallel to the main flow path and the substantially vertical L-shaped introduction vertical groove 92 that raises the fluid flowing in from the introduction hole 91. The first sub-channel 93 and the third sub-channel 95 that are formed, the second sub-channel 94 and the fourth sub-channel 96 that are formed in a direction orthogonal to the main channel, and the main flow of fluid from the discharge port 98 It is comprised from the discharge vertical groove 97 discharged to the path A. Since the introduction vertical groove 92 has a planar L shape, a part of the fluid that flows in flows in the opposite direction to the flow in the main flow path A, but dust and the like flow in the opposite direction because their mass is larger than expected. It is difficult for dust and the like to flow into the discharge vertical groove 97 via the first sub-flow channel 93. Part of the fluid that has flowed in flows through the two second sub-channels 94 and merges, and then communicates with the third channel 95 that is the detection channel. A narrow detection area is formed so that the protrusion 99a faces the partition wall 99 provided on both sides of the third flow path 95, and the non-uniform flow of the fluid is corrected by narrowing the flow path. . The detected fluid branches into two fourth flow paths 96 and communicates with the discharge vertical groove 97. Finally, it communicates with the main flow path A through the discharge outlet 98 (see, for example, Patent Document 1).

JP 2006-308518 A

  However, in the flow meter disclosed in Patent Document 1 described above, it is difficult to secure a space for sufficiently rectifying the fluid when the channel is formed in a small size, and the fluid is disturbed in the flow rate detection channel. There was a problem that occurred. Moreover, it is difficult to secure a space for providing a wire mesh for improving the fluid rectifying effect on the upstream side, and even if it is possible to arrange the wire mesh, it is difficult to arrange the number of wire meshes that sufficiently obtain the rectifying effect.

  The present invention has been made to solve the above-described problems, and provides a flow meter having a flow channel structure that can exhibit a sufficient rectifying effect even in a flow meter with a small flow channel. The purpose is to do.

  A flow meter according to the present invention is a flow meter including a sensor that detects a fluid to be measured and a fluid measurement unit that measures a flow rate of the fluid to be measured based on a detection result of the sensor. A first flow path formed on the surface of the body part side through which the fluid to be measured separated from the body part enters and exits, the body part side, and a plate-like member provided between the part and the fluid measurement part A communication hole portion communicating with the fluid measurement portion side and a second fluid formed on the surface of the fluid measurement portion side and exposed to the sensor through the first flow path and the communication hole portion are exposed to the sensor. A flow path structure having a flow path, the flow path structure being divided into a first rectification section on the upstream side of the flow of the fluid to be measured and a second rectification section on the downstream side, and A buffer part consisting of a recess where the fluid to be measured flowing from the body part accumulates The provided first rectifying portion and second rectifying portion, in which and a commutator to arrange the flow of the fluid to be measured flows from the buffer unit to the communication hole.

  In the flowmeter according to the present invention, the flow velocity vector of the fluid to be measured flowing through the main flow channel of the body portion and the flow velocity vector of the fluid to be measured exposed to the sensor in the second flow channel are substantially orthogonal.

  In the flowmeter according to the present invention, the commutator is a plurality of convex portions extending from the opening portion of the communication hole portion, and the plurality of convex portions are formed shorter as the length from the communication hole portion approaches the buffer portion. The flow of the fluid to be measured from the buffer portion is guided to the communication hole portion through the convex portions.

  The flow meter according to the present invention includes a wire mesh locking piece for locking a wire mesh that rectifies the fluid to be measured flowing through the second flow path to the sensor side.

  According to the present invention, the first flow path, the communication hole, and the second flow path are provided, the flow path is folded back, and the flow rate of the fluid to be measured is a buffer portion that is a recess in which the fluid to be measured flowing from the body portion accumulates. Since the commutator is used to adjust the flow of the fluid to be measured by the commutator after lowering the flow rate, the flow length through which the fluid to be measured flows can be sufficiently secured to perform rectification, and accurate flow measurement Can be realized. Furthermore, the flow meter can be reduced in size.

  According to the present invention, since the flow velocity vector of the fluid to be measured flowing through the main flow channel of the body portion and the flow velocity vector of the fluid to be measured exposed to the sensor in the second flow channel are configured to be substantially orthogonal to each other, Even when the body portion is arranged so that the fluid to be measured flowing through the main flow path flows in the direction of gravity, such as by attaching a meter, the sensor is provided so as to be parallel to the flow velocity vector of the fluid to be measured exposed to the sensor. The temperature distribution of the fluid to be measured around the upstream and downstream resistances does not have to be biased toward either resistance. Furthermore, it is possible to sufficiently secure the flow path length through which the fluid to be measured flows.

  According to this invention, since the length from the communicating hole portion of the commutator, which is a plurality of convex portions extending from the opening portion of the communicating hole portion, is shortened as it approaches the buffer portion, the first from the buffer portion. The inlet of the flow path toward the rectifying unit or the second rectifying unit is widened, and the fluid to be measured that passes through the rectifying unit can flow as evenly as possible to obtain a rectifying effect.

  According to the present invention, since the wire mesh locking piece for locking the wire mesh for rectifying the fluid to be measured flowing in the second flow path to the sensor side is provided, it is further sufficient before the fluid to be measured is exposed to the sensor. Rectification can be performed.

Embodiment 1 FIG.
1 is an exploded perspective view of a flow meter according to Embodiment 1 of the present invention. As shown in FIG. 1, the flow meter 1 includes a filter 2, a flow path structure portion 3, a metal mesh 4, a rubber packing 5 having an elliptical fracture surface, a flow rate sensor 6, a measurement portion 7, support plates 7 a and 7 b, and a display portion 8. The sensor unit (fluid measuring unit) 9 is provided.
The filter 2 is detachably attached to the flow path structure portion 3 and removes dust (foreign matter) of the fluid to be measured introduced from the body portion described later. In addition, you may comprise without providing a filter as needed. The flow path structure portion 3 is fixed to the support plate 7a with a double-sided tape, an adhesive, or the like, reduces the flow velocity of the fluid to be measured introduced from the body portion, and rectifies the drift or turbulence of the fluid to be measured, thereby controlling the flow rate sensor 6. It is the adjustment body formed in the ellipse to introduce into. In addition, by providing the flow path structure portion 3, it functions as a lid that covers the flow rate sensor 6 when the sensor unit 9 is removed from the body portion, and the flow rate sensor 6 portion of the sensor unit 9 is exposed and damaged. Can be prevented. In addition to being attached to the support plate 7a with a double-sided tape or an adhesive, the flow path structure unit 3 may be attached so as not to easily fall off the support plate 7a by other methods.

  The metal mesh 4 is a rectifying element for rectifying the drift or turbulence of the fluid to be measured before being introduced into the flow sensor 6, and a plurality of pieces are arranged on the upstream side of the flow sensor 6 at regular intervals. In consideration of the flow velocity of the fluid to be measured supplied to the flow sensor, the number of wire meshes 4 to be arranged, the roughness of the mesh, or the arrangement interval may be changed. The rubber packing 5 is an elastic body and is formed in an ellipse like the flow path structure 3. The flow rate sensor 6 is disposed at the center of the support plate 7a of the sensor unit 9, and the support plate 7b is formed with an elliptical hole similar to the flow path structure 3 and the rubber packing 5. Although the flow path structure 3 and the sensor unit 9 can be attached to and detached from the body part, the flow path structure 3 is not easily removed because it is fixed to the support plate 7a of the sensor unit 9 with a double-sided tape or the like. The flow sensor 6 detects the flow rate of the fluid to be measured rectified by the wire mesh 4 and outputs a detection signal to the measuring unit 7 from a lead wire (not shown) or the like.

FIG. 2 is a front view of the sensor unit of the flowmeter according to Embodiment 1 of the present invention.
The measuring unit 7 has a connector 71 for inserting a network cable or the like for connecting to an external device. The support plates 7a and 7b are provided with screws 72 that are fixed when the sensor unit 9 and the body portion 9a are connected. By screwing the sensor unit 9 and the body portion 9a with the screw 72, the rubber packing 5 comes into contact with the mounting surfaces of the support plate 7a and the body portion 9a to maintain airtightness. The display unit 8 includes a setting switch 81 that performs setting input, and a display 82 that displays the setting content of the setting switch 81 and the like. In the example of FIG. 2, the case where the sensor unit 9 is equipped with the display unit 8 is shown, but a configuration without the display unit may be used.

  FIG. 3 is a diagram showing attachment of the sensor unit according to Embodiment 1 of the present invention to the body portion. The body portion 9a includes a main channel 9b, an orifice 9c, and branch channels 9d and 9e. Moreover, the arrow described in the main flow path 9b has shown the flow velocity vector of the to-be-measured fluid which flows through the main flow path 9b. The branch channels 9d and 9e are formed so as to communicate with the main channel 9b before and after the orifice 9c. Further, the diversion channels 9d and 9e are formed at positions parallel to the flow velocity vector of the fluid to be measured indicated by arrows in FIG. The fluid to be measured is diverted to the flow channel structure 3 through the flow dividing channel 9d by the differential pressure generated in the orifice 9c, and the fluid to be measured that has passed through the flow channel structural unit 3 flows out to the main flow channel 9b through the flow dividing channel 9e. To do. In the following description, the flow of the fluid to be measured traveling from the branch channel 9d toward the flow channel structure 3 is referred to as forward flow, and the flow of the fluid to be measured from the flow channel 9e toward the flow channel structure 3 is referred to as reverse flow.

4 is a perspective view of a flow path structure portion of the flowmeter according to the first embodiment of the present invention, FIG. 4 (a) is a configuration of a body portion side surface, FIG. 4 (b) is a configuration of a measurement portion side surface, FIG. 4C shows a view in which the channel structure is attached to the hole of the support plate.
The flow path structure 3 is die-cut using resin or the like, and as shown in FIG. 4A, a substantially S-shaped partition wall is provided at the center of the body side surface (first flow path) 3a. 10, an upstream flow path (first rectification unit) 11, a downstream flow path 12 (second rectification unit) 12, and buffer recesses (buffer units) 13 and 14 partitioned by the partition wall 10. It is composed of An outer peripheral wall 15 is formed on the outer peripheral portion of the body side surface 3a so as to be connected to the partition wall 10, and the fluid to be measured introduced when the sensor unit 9 is attached to the body portion 9a. Prevent leakage. The flow path structure 3 may be formed by cutting a metal.

  4A, the area of the downstream flow path 12 may be configured to be smaller than that of the upstream flow path 11, or the area of the upstream flow path 11 and the downstream flow path 12 may be configured. You may comprise so that the area of may become equal. In the configuration shown in FIG. 4A, when measuring a fluid to be measured in a reverse flow, the introduced fluid to be measured is rectified in the downstream flow path 12 and then introduced into the flow sensor 6. Since the fluid to be measured introduced into the flow path 12 is a small amount compared to the measurement in the forward flow direction, the area of the downstream flow path 12 is made smaller than that of the upstream flow path 11. If necessary, the area of the downstream channel 12 need not be smaller than the area of the upstream channel 11.

  In the upstream flow path 11, three rectifying pieces (commutators) 11 a, 11 b and 11 c having different lengths and a fluid to be measured are introduced from the body side surface 3 a to the measurement unit side surface (second flow path) 3 b. A channel bending hole (communication hole portion) 11d is formed. The rectifying piece 11 a is connected to the outer peripheral wall 15, and is configured such that the height of the rectifying pieces 11 b and 11 c is higher than the rectifying pieces 11 b and 11 c in order to enhance the buffer effect by the buffer recess 13. In addition, the length of each rectifying piece is configured to satisfy 11a <11b <11c so that the fluid to be measured can communicate between the respective rectifying pieces 11a, 11b, and 11c. By making the length of the rectifying piece 11a the shortest, the inlet of the flow path from the buffer recess 13 toward the flow path bending hole 11b widens, and the rectifying pieces 11a, 11b, and 11c formed in the upstream flow path 11 are partitioned. The fluid to be measured can be made to flow as uniformly as possible through each of the three flow paths, and a rectifying effect can be obtained.

  Similarly, the downstream flow path 12 has three flow straightening pieces (commutators) 12a, 12b and 12c having different lengths and flow path bending holes (communication) for introducing the fluid to be measured from the measurement unit side surface 3b to the body side surface 3a. A hole 12d is formed. The rectifying piece 12 a is connected to the outer peripheral wall 15, and is configured such that the height of the rectifying pieces 12 b and 12 c is higher than that of the rectifying pieces 12 b and 12 c in order to enhance the buffer effect by the buffer recess 14. Further, the length of each rectifying piece is configured to satisfy 12a <12b <12c so that the fluid to be measured can communicate between the respective rectifying pieces 12a, 12b, and 12c. By making the length of the rectifying piece 12a the shortest, the inlet of the flow path from the buffer recess 14 toward the flow path bending hole 12b widens, and the rectifying pieces 12a, 12b and 12c formed in the downstream flow path 12 are partitioned. The fluid to be measured can be made to flow as uniformly as possible through each of the three flow paths, and a rectifying effect can be obtained.

  The downstream channel 12 is different from the upstream channel 11 in that the rectifying pieces 12b and 12c are formed so as to straddle the channel folding hole 12d, and the channel folding hole 12d is divided into three. . The flow path bending hole can improve the flow straightening effect of the fluid to be measured more if it is not divided by the flow straightening piece, but the flow path bending hole of the downstream flow path 12 has little influence on the flow rate measurement of the fluid to be measured in the forward flow direction. The rectifying pieces 12b and 12c may be formed so as to straddle 12d.

  Next, the structure of the measurement part side surface 3b is demonstrated using FIG.4 (b). Flow path bending holes 11d and 12d shown in the description of FIG. 4A are formed at both ends of the measurement unit side surface 3b. Further, four wire mesh locking pieces 16, two wall portions 17 a and 17 b, and two sill pieces 18 a and 18 b for locking the wire mesh 4 are provided at the center of the measurement unit side surface 3 b. In the present embodiment, the measurement range of the forward flow fluid measurement is wider than the measurement range of the forward flow fluid measurement, and thus the wire mesh is provided in the flow path in order to obtain a further rectifying effect.

  By inserting the wire mesh 4 between the ends of the sill pieces 18a and 18b on the flow path bending hole 11d side and the four wire mesh locking pieces 16, as shown in FIG. A plurality of wire meshes 4 are arranged at regular intervals. The walls 17a and 17b and the sill pieces 18a and 18b can uniformly adjust the flow velocity vector of the fluid to be measured introduced into the flow sensor 6 and can obtain a rectifying effect. The sill pieces 18a, 18b are formed so as to straddle the flow path bending hole 12d.

  Next, the flow sensor 6 will be described. As the flow sensor 6, for example, the one having a semiconductor diaphragm configuration disclosed by the applicant of the present application in the specification of Japanese Patent Application No. 3-106528 can be used. FIG. 5 is a diagram showing the configuration of the flow sensor of the flow meter according to the first embodiment of the present invention. FIG. 5 (a) is a perspective view of the flow sensor, and FIG. 5 (b) is a diagram of FIG. 5 (a). It is AA sectional drawing. The flow sensor 6 has a heater 61, an upstream temperature sensor 62, a downstream temperature sensor 63, an ambient temperature sensor on the surface of a base 60 made of a base material such as a silicon chip having a side of 1.7 mm and a thickness of 0.5 mm. 64 is formed as a thin film using a pattern such as platinum and covered with an insulating film layer 65. The resistance value of the platinum thin film changes depending on the temperature and functions as a resistance temperature detector.

  The heater 61 is disposed at the center of the base 60, an upstream temperature sensor 62 is disposed upstream of the heater 61 with respect to the fluid flow direction, and a downstream temperature sensor 63 is disposed downstream of the opposite side. Yes. In addition, the ambient temperature sensor 64 is disposed in the upstream peripheral portion of the base 60. In the central portion of the base 60, a part of the base material is removed by a process such as anisotropic etching to form a cavity (recessed space) 66, and a heater 61, an upstream temperature sensor 62, and a downstream temperature are formed. The sensor 63 is formed on a diaphragm 67 that is thermally insulated from the base 60.

  The operation principle of the flow sensor 6 is that the fluid is heated by the heater 61 so as to be higher than the fluid temperature measured by the ambient temperature sensor 64 by a certain temperature, for example, several tens of degrees centigrade, and a predetermined temperature distribution is generated. By measuring with the upstream temperature sensor 62 and the downstream temperature sensor 63, the fluid flow rate is measured. When the fluid is stationary, the temperature distribution obtained by the upstream temperature sensor 62 and the downstream temperature sensor 63 is symmetric. However, when the fluid is flowing, the symmetry is lost and compared with the upstream temperature sensor 62. Thus, the temperature obtained by the downstream temperature sensor 63 increases. By detecting this temperature difference with a bridge circuit, a fluid flow rate can be obtained based on physical properties such as the thermal conductivity of the fluid.

  The flow sensor 6 is not only small in size but also has the features of high sensitivity analysis, high speed response and low power consumption because it employs an extremely thin diaphragm structure that is thermally insulated. Moreover, since the arrangement of the upstream temperature sensor 62 and the downstream temperature sensor 63 with the heater 61 interposed therebetween is symmetrical, not only forward flow but also reverse flow can be measured.

FIG. 6 is a diagram showing the operation of the flow meter according to Embodiment 1 of the present invention. FIG. 6A is a front view of the side surface of the body portion of the flow path structure portion showing the forward flow of the fluid to be measured, and FIG. 6B is a flow path structure portion showing the forward flow of the fluid to be measured. It is a front view of the measurement part side. In FIG. 6, the solid line arrows indicate the flow of the fluid to be measured before the flow rate measurement, and the broken line arrows indicate the flow of the fluid to be measured after the flow rate measurement.
First, the fluid to be measured introduced from the branch channel 9d indicated by the solid line arrow in FIG. 6A to the buffer recess 13 has a certain angle spread and is introduced into the upstream channel 11. The fluid to be measured to be introduced is introduced with a constant angle spread because the gap between the partition wall 10 and the rectifying piece 11a is wide, so that the flow velocity is suppressed. The introduced fluid to be measured has its flow direction changed by the partition wall 10 and passes between the rectifying pieces 11a, 11b and 11c to be rectified. The fluid to be measured is rectified and the flow velocity vector gradually changes, the flow direction is changed in the flow path bending hole 11d, and the fluid is introduced into the measurement unit side surface 3b.

  As shown by the solid line arrow in FIG. 6 (b), the fluid to be measured introduced from the body side surface 3a is rectified by the wire mesh 4, and then the flow-in area is determined by the walls 17a and 17b. 18b, the flow velocity vector of the fluid to be measured flowing into the flow sensor 6 is made uniform, and the flow rate is detected by the flow sensor 6. The flow velocity vector of the fluid to be measured flowing into the flow sensor 6 changes in a direction substantially orthogonal to the flow velocity vector of the fluid to be measured flowing through the main flow path 9b. A detection signal detected by the flow sensor 6 is output to the measurement unit 7.

  Thereafter, the direction of the flow of the fluid to be measured is changed again in the flow path bending hole 12d and introduced into the body side surface 3a. As shown by the dotted arrows in FIG. 6A, the fluid to be measured introduced from the measurement unit side surface 3b passes between the rectifying pieces 12a, 12b and 12c and is rectified. The rectified fluid to be measured joins the gas flow from the branch flow path 9e to the main flow path 9b via the buffer recess 14 and the filter 2.

Next, the operation of the flow meter that measures the flow rate of the fluid to be measured in the reverse flow direction will be described.
FIG. 7 is a diagram showing the operation of the flow meter according to the first embodiment of the present invention. FIG. 7A is a perspective view of the side of the body portion of the flow channel structure showing the back flow of the fluid to be measured, and FIG. 7B is the flow path structure showing the back flow of the fluid to be measured. It is a perspective view of the measurement part side surface. In FIG. 7, the solid line arrows indicate the flow of the fluid to be measured before the flow rate measurement, and the broken line arrows indicate the flow of the fluid to be measured after the flow rate measurement.

  First, the fluid to be measured introduced into the buffer recess 14 from the branch channel 9e indicated by the solid line arrow in FIG. 7A has a certain angle spread and is introduced into the downstream channel 12. Since the introduced fluid to be measured has a wide space between the partition wall 10 and the rectifying piece 12a, the flow velocity is suppressed and the fluid to be measured is introduced with a certain angular spread. The introduced fluid to be measured has its flow direction changed by the partition wall 10 and passes between the rectifying pieces 12a, 12b and 12c to be rectified. The fluid to be measured is rectified and the flow velocity vector gradually changes, the flow direction is changed in the flow path bending hole 12d, and the fluid is introduced into the measurement unit side surface 3b.

  As shown by the solid line arrow in FIG. 7B, the fluid to be measured introduced from the body side surface 3a is the fluid to be measured that flows into the flow sensor 6 through the walls 17a and 17b and the sill pieces 18a and 18b. The flow velocity vector is made uniform, and the flow rate is detected by the flow rate sensor 6. The flow velocity vector of the fluid to be measured flowing into the flow sensor 6 changes in a direction substantially orthogonal to the flow velocity vector of the fluid to be measured flowing through the main flow path 9b. A detection signal detected by the flow sensor 6 is output to the measurement unit 7.

  After that, the fluid to be measured is rectified by the wire mesh 4, and then the flow direction is changed again at the flow path bending hole 11d and introduced into the body side surface 3a. As shown by the dotted arrows in FIG. 6A, the fluid to be measured introduced from the measurement unit side surface 3b passes between the rectifying pieces 11a, 11b, and 11c and is rectified. The rectified fluid to be measured joins the gas flow in the main channel 9b from the branch channel 9d via the buffer recess 13 and the filter 2.

  As described above, according to the first embodiment, the flow channel structure is provided with the body part side surface, the measurement unit side surface, and the flow path bending hole, and the flow path of the fluid to be measured is folded back. Since the commutator for adjusting the flow of the fluid to be measured is provided by the commutator after the flow velocity of the fluid is reduced, the flow path through which the fluid to be measured flows can be sufficiently secured and rectified. It is possible to measure the flow rate. In addition, the flow meter can be reduced in size.

  When the body is arranged so that the fluid to be measured flowing through the main flow path flows in the direction of gravity, such as by attaching a flow meter to the vertical pipe, the flow velocity vector of the fluid to be measured flowing through the main flow path and the measurement to be exposed to the flow sensor When the flow velocity vector of the fluid is the same, the temperature distribution of the fluid to be measured around the upstream and downstream resistances provided in the sensor is parallel to the flow velocity vector of the fluid to be measured exposed to the flow sensor. It is known to bias towards resistance. In this case, especially when the flow rate is low or zero, the measurement error and the drift of the zero point are conspicuous. According to the first embodiment, the flow velocity vector of the fluid to be measured flowing through the main flow path and the measurement unit Since the flow velocity vector of the fluid to be measured flowing into the flow sensor on the side surface is substantially orthogonal, the flow velocity vector of the fluid to be measured exposed to the flow sensor can be configured to be orthogonal to the direction of gravity. The temperature distribution of the fluid to be measured around the upstream and downstream resistances provided in the sensor so as to be parallel to the flow velocity vector of the fluid to be measured exposed to is not required to be biased toward either resistance. Measurement errors at low flow rates and zero point drift at zero flow rates can be suppressed. Furthermore, it is possible to sufficiently secure the flow path length through which the fluid to be measured flows.

  Furthermore, according to the first embodiment, a plurality of rectifying pieces are provided on the side surface of the body part, and after the flow rate of the fluid to be measured introduced from the branch channel of the body part is lowered, the flow of the fluid to be measured is further flown by each rectifying piece. The flow rate of the fluid to be measured can be stably measured. In addition, since the length of the rectifying piece is shortened as it approaches the buffer recess, the inlet extends to the flow path toward the buffer rectification first rectification unit or the second rectification unit, and the rectification piece is partitioned by a plurality of rectification pieces. The fluid to be measured can be made to flow as uniformly as possible in the respective flow paths, and a rectifying effect can be obtained.

  Further, according to the first embodiment, since the plurality of rectifying pieces and the channel bending holes are provided in the downstream channel on the side surface of the body part, and the flow sensor having a bilaterally symmetric structure is provided, It is also possible to measure the flow rate of the reverse flow, which is the flow of the fluid to be measured, from the path toward the flow sensor.

  Furthermore, according to the first embodiment, the flow path structure portion is provided at a position covering the flow rate sensor, and the fluid to be measured introduced from the body portion side is folded and supplied to the flow rate sensor. Even when it is removed from the body portion, the flow path structure portion functions as a lid for the flow rate sensor, and it is possible to prevent the flow rate sensor from being exposed and damaged or damaged.

  In the first embodiment, an example in which the flow path structure portion, the rubber packing, and the hole portions of the support plate are formed in an elliptical shape is shown. However, the shape is not limited to the elliptical shape, and the body into which the fluid to be measured is introduced You may comprise according to the shape of the partial flow path of a part.

  In the first embodiment, a configuration is shown in which a wire mesh is provided in the vicinity of the flow path folding hole 11d. However, a wire mesh is also provided immediately after the flow path bending hole 12d, so that a reverse flow introduced from the downstream flow path 12 is prevented. The fluid to be measured may be supplied to the flow sensor 6 after being rectified by the wire mesh.

It is a disassembled perspective view of the flowmeter which concerns on Embodiment 1 of this invention. It is a front view of the sensor unit of the flowmeter which concerns on Embodiment 1 of this invention. It is a figure which shows the attachment to the body part of the sensor unit which concerns on Embodiment 1 of this invention. It is a perspective view of the flow-path structure part of the flowmeter which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the flow sensor of the flowmeter which concerns on Embodiment 1 of this invention. It is a figure which shows operation | movement of the flowmeter which concerns on Embodiment 1 of this invention. It is a figure which shows operation | movement of the flowmeter which concerns on Embodiment 1 of this invention. It is a fragmentary sectional view of the conventional flowmeter. It is a fragmentary sectional view of the conventional flowmeter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flowmeter 2 Filter 3 Flow path structure part 3a Body part side surface 3b Measurement part side surface 4 Wire mesh 5 Rubber packing 6 Flow sensor 7 Measurement part 7a, 7b Support plate 8 Display part 9 Sensor unit 9a Body part 9b Main flow path 9c Orifice 9d, 9e Dividing channel 10 Partition wall 11 Upstream channel 12 Downstream channel 11a, 11b, 11c, 12a, 12b, 12c Rectifying piece 11d, 12d Channel bending hole 13, 14 Buffer recess 15 Outer wall 16a, 16b, 16c , 16d Wire mesh locking piece 17a, 17b Wall 18a, 18b Sill piece 60 Base 61 Heater 62 Upstream temperature sensor 63 Downstream temperature sensor 64 Ambient temperature sensor 65 Insulating film layer 66 Cavity (recessed space)
67 Diaphragm 71 Connector 72 Screw 81 Setting switch 82 Display 90 Flowmeter 91 Advanced device 92 Ceramic substrate 93 Conductor pattern 94 Chip component 95 Circuit board 96 U-shaped flow path

Claims (4)

In a flow meter comprising a sensor for detecting a fluid to be measured and a fluid measuring unit for measuring a flow rate of the fluid to be measured based on a detection result of the sensor,
A first flow path formed on a surface of the body portion side into which the fluid to be measured enters and exits from the body portion, the plate portion being provided between the body portion through which the fluid to be measured flows and the fluid measuring portion; The fluid to be measured is formed on the surface on the fluid measurement unit side and the communication hole part communicating the body part side and the fluid measurement unit side, and enters and exits through the first flow path and the communication hole unit. A flow path structure having a second flow path exposed to the sensor;
The flow path structure section includes a partition wall that divides the first rectification section on the upstream side and the second rectification section on the downstream side of the flow of the fluid to be measured,
A buffer portion consisting of a concave portion in which the fluid to be measured flowing from the body portion accumulates;
A flowmeter comprising: a commutator provided in the first rectifying unit and the second rectifying unit, for adjusting a flow of a fluid to be measured flowing from the buffer unit toward the communication hole.   2. The flowmeter according to claim 1, wherein the flow velocity vector of the fluid to be measured flowing through the main flow path of the body portion and the flow velocity vector of the fluid to be measured exposed to the sensor in the second flow path are substantially orthogonal. The commutator is a plurality of convex portions extending from the opening of the communication hole,
The plurality of convex portions are formed shorter as the length from the communication hole portion approaches the buffer portion, and the flow of the fluid to be measured from the buffer portion passes between the convex portions to the communication hole portion. The flowmeter according to claim 1, wherein the flowmeter is guided.   The flow rate according to any one of claims 1 to 3, further comprising a wire mesh locking piece for locking a wire mesh that rectifies the fluid to be measured flowing through the second flow path to the sensor side. Total.

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