CN210123295U

CN210123295U - Flow rate measuring device

Info

Publication number: CN210123295U
Application number: CN201921233725.XU
Authority: CN
Inventors: 山本克行
Original assignee: Omron Corp
Current assignee: Omron Corp
Priority date: 2019-07-31
Filing date: 2019-07-31
Publication date: 2020-03-03
Anticipated expiration: 2029-07-31

Abstract

A flow rate measuring device reduces a change in output characteristics caused by a change in physical properties of a fluid to be measured. A flow rate measurement device (1) is provided with: a flow rate sensor (8) for detecting the flow rate of the fluid to be measured flowing through the main channel (21); a physical property value sensor (7) having a micro-heater and a thermopile and detecting a physical property value of the fluid to be measured; a sub-channel section (3) having a physical property value detection channel (32) in which a physical property value sensor (7) is disposed; and a flow rate correction unit that corrects the flow rate of the fluid to be measured calculated based on the temperature signal output from the flow rate sensor (8) using the physical property value of the fluid to be measured calculated based on the temperature signal output from the physical property value sensor (7). The micro-heater and the thermopile are arranged in a direction orthogonal to the flow direction of the fluid to be measured, and the flow rate sensor (8) is arranged at a position other than the physical property value detection flow path (32).

Description

Flow rate measuring device

Technical Field

The present invention relates to a flow rate measuring apparatus for measuring a flow rate of a fluid flowing through a flow path, and more particularly, to a flow rate measuring apparatus capable of reducing a change in output characteristics due to a change in physical properties of the fluid and measuring the flow rate with high accuracy.

Background

Conventionally, in order to measure a flow rate of a fluid such as a gas (hereinafter, referred to as a measurement target fluid) flowing through a flow channel, a thermal type flow rate measurement device that measures the flow rate of the measurement target fluid based on a change in a temperature distribution in the flow channel has been used.

Fig. 14 is a schematic diagram for explaining a change in temperature distribution in the thermal type flow rate measurement device, where fig. 14 (a) shows the temperature distribution in a state where the measurement target fluid does not flow, and fig. 14 (b) shows the temperature distribution in a state where the measurement target fluid flows.

As shown in fig. 14 (a), in a state where the fluid to be measured does not flow, the fluid to be measured located in the periphery is heated by the micro-heater 181, and a uniform temperature distribution is generated in the thermopile 182 disposed on the upstream side of the micro-heater 181 and the thermopile 183 disposed on the downstream side of the micro-heater 181.

In this state, when the fluid to be measured flows in the direction of the arrow in the drawing, the temperature distribution around the microheater 181 is biased toward the downstream side of the fluid to be measured, that is, the thermopile 183 side, as shown in fig. 14 (b). Therefore, the thermopile 182 detects a temperature lower than that in a state in which the fluid to be measured does not flow, and the thermopile 183 detects a temperature higher than that in a state in which the fluid to be measured does not flow.

In this way, in the thermal type flow rate measurement device, the flow rate can be measured with high accuracy by calculating the measurement target fluid flowing through the flow path based on the difference in temperature detected by the thermopile 182 and the thermopile 183.

However, when the kind, composition, or the like of the fluid to be measured changes, the physical property values such as thermal conductivity, specific heat, viscosity, and density also change. Therefore, the conventional thermal flow rate measurement device has a problem that the output characteristics vary depending on the physical property value of the fluid to be measured.

Fig. 15 (a) and (b) are schematic diagrams showing temperature distributions when GasA and GasB having different physical property values are respectively caused to flow through the flow channel 121 at a predetermined flow rate (L/min), and fig. 16 is a graph showing a relationship between the flow rates (L/min) of GasA and GasB and the output value (V) of the flow rate measuring device shown in fig. 15 (a) and (b).

As shown in fig. 15 (a) and (b), even when the fluid to be measured flows through the flow channel 121 at the same flow rate, the temperature distribution around the micro-heater 181 differs between GasA and GasB having different physical property values.

Therefore, as shown in fig. 16, in GasA and GasB having different physical property values, the output value (V) of the flow rate measuring device changes even at the same flow rate, and the amount of change increases as the flow rate increases.

As described above, in the conventional thermal type flow rate measurement device, when the physical property value of the fluid to be measured changes, the output characteristic of the flow rate measurement device also changes, and therefore, it is difficult to perform high-precision flow rate measurement.

In order to solve such a problem, patent documents 1 and 2 disclose a flow rate measuring apparatus including a physical property value sensor for detecting a physical property value of a fluid to be measured.

Fig. 17 is a plan view showing a structure of a micro flow sensor 207 provided in the flow rate measurement device disclosed in patent document 1, and fig. 18 is a perspective view showing an external appearance of the flow rate measurement device disclosed in patent document 2.

As shown in fig. 17, the thermopile 282,283 for measuring a flow rate and the

thermopiles

272 and 273 for measuring physical property values of the micro-flow sensor 207 of patent document 1 are arranged on the substrate 205 along the four sides of the micro-heater 281.

Specifically, a flow rate measurement thermopile 282 is disposed upstream of the micro-heater 281 and a flow rate measurement thermopile 283 is disposed downstream of the micro-heater 281 with respect to the flow direction R of the fluid to be measured. Further,

thermopiles

272 and 273 for measuring physical property values are disposed at both ends in the longitudinal direction (direction orthogonal to the flow direction R) of the micro-heater 281.

As shown in fig. 18, the flow rate measuring device 301 of patent document 2 has a flow rate sensor 308 disposed on the inner wall of a main flow path 321, and a physical property value sensor 307 disposed inside a unit 336 provided so as to branch from the main flow path 321.

According to patent document 1 and patent document 2, the physical property value of the fluid to be measured is calculated based on the output value of the physical property value sensor, and the flow rate of the fluid to be measured is corrected using the calculated physical property value, whereby the change in the output characteristic of the flow rate measuring device due to the change in the physical property of the fluid to be measured can be reduced.

Patent document 1: japanese patent No. 4050857 (granted on 12-7-month-2007)

Patent document 2: U.S. patent No. 5237523 (granted on 8-month-17-day 1993)

Here, the flow rate sensor and the physical property value sensor have unique detection ranges, and when the flow rate of the fluid to be measured deviates from the detection range, the measurement accuracy is lowered or the measurement is impossible. Therefore, in order to improve the measurement accuracy of the flow rate measurement device, it is necessary to individually control the optimum flow rate according to the detection ranges of the flow rate sensor and the physical property value sensor.

However, in the technique of patent document 1, the flow rate detection thermopile 282,283 and the

property detection thermopiles

272 and 273 provided on the substrate 205 are arranged in the same flow path, and therefore, the optimum flow rate cannot be individually controlled for each of the flow rate sensor and the property value sensor.

Therefore, in the technique of patent document 1, since the output characteristics of the physical property value sensor (the physical property detection thermopiles 272 and 273) are changed by the influence of the flow rate, it is necessary to further correct the calculated physical property value in accordance with the flow rate. That is, as shown in the following equation (1), it is necessary to correct the physical property value (coefficient) detected to correct the flow rate output value using the flow rate output value before correction.

[ formula 1]

Corrected flow output value ═

Equation (1) for calculating the flow output value x before correction (coefficient corresponding to physical property value x flow output value before correction) …

Therefore, in the technique of patent document 1, the error due to the physical property value cannot be completely corrected, and therefore, the flow rate of the fluid to be measured cannot be measured with high accuracy.

In addition, in the technique of patent document 2, since the main channel 321 and the unit 336 are configured to communicate with each other by one pipe, the inflow and outflow of the fluid to be measured that flows out into the unit 336 are not stopped, and the fluid to be measured in the unit 336 cannot be efficiently replaced.

Therefore, in the technique of patent document 2, for example, when the physical property of the measurement target fluid changes, the physical property value sensor 307 cannot detect an appropriate physical property value because the physical property of the measurement target fluid flowing through the physical property value sensor 307 arranged in the unit 336 is different from the physical property of the measurement target fluid flowing through the flow rate sensor 308 arranged in the main flow path 321.

Therefore, in the technique of patent document 2, since precise correction cannot be performed based on the physical property value, the flow rate of the fluid to be measured cannot be measured with high accuracy.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved by the utility model

The present invention has been made in view of the above problems, and an object of the present invention is to provide a flow rate measuring apparatus capable of measuring a flow rate of a fluid to be measured with high accuracy while reducing a change in output characteristics due to a change in physical properties of the fluid to be measured.

Technical solution for solving technical problem

In order to solve the above technical problem, the utility model discloses a flow measurement device's characterized in that possesses: a flow rate detection unit for detecting a flow rate of a fluid to be measured flowing through the main flow path; a physical property value detection unit having a heating unit that heats a fluid to be measured and a temperature detection unit that detects a temperature of the fluid to be measured, and detecting a physical property value of the fluid to be measured; a sub-channel section having a property value detection channel having one end communicating with a first inlet opening in the main channel and the other end communicating with a first outlet opening in the main channel, and in which the property value detection section is disposed; a flow rate correction unit that corrects the flow rate of the fluid to be measured calculated based on the detection signal output from the flow rate detection unit, using the physical property value of the fluid to be measured calculated based on the detection signal output from the physical property value detection unit; the heating unit and the temperature detection unit are arranged in a direction orthogonal to the flow direction of the fluid to be measured, and the flow rate detection unit is arranged at a position other than the physical property value detection flow path.

In the above configuration, the physical property value detection unit is disposed in the physical property value detection flow path, and the flow rate detection unit is disposed at a position other than the physical property value detection flow path. Therefore, for example, by controlling the flow rate of the fluid to be measured flowing through the property value detection flow path by adjusting the width of the property value detection flow path, it is possible to suppress the output characteristic of the property value detection unit from changing due to the influence of the flow rate, and it is possible to efficiently suppress the occurrence of turbulent flow caused by the flow of the fluid to be measured.

Therefore, according to the above configuration, the flow rate correction unit can accurately correct the flow rate of the fluid to be measured calculated based on the detection signal output from the flow rate detection unit, using the high-accuracy physical property value calculated based on the detection signal output from the physical property value detection unit.

In the above configuration, the physical property value detection unit is disposed in the physical property value detection flow path having one end communicating with the first inlet opening in the main flow path and the other end communicating with the first outlet opening in the main flow path. Therefore, the fluid to be measured flows from the first inlet to the first outlet without being stagnated, and therefore the fluid to be measured existing around the physical property value detection unit can be efficiently replaced.

Therefore, according to the above configuration, even when the physical property value of the fluid to be measured flowing through the main channel changes, the flow rate of the fluid to be measured can be corrected based on the appropriate physical property value.

In the above configuration, the heating unit and the temperature detection unit included in the physical property value detection unit are arranged in a direction orthogonal to the flow direction of the measurement target fluid flowing into the physical property value detection region. Since the temperature distribution of the fluid to be measured is shifted to the downstream side by the flow of the fluid, the change in the temperature distribution in the direction orthogonal to the flow direction is smaller than the change in the temperature distribution in the flow direction of the fluid to be measured. Therefore, by arranging the heating unit and the temperature detection unit in an array in a direction orthogonal to the flow direction of the fluid to be measured, it is possible to reduce the change in the output characteristic of the temperature detection unit due to the change in the temperature distribution.

Therefore, according to the above configuration, the influence of the change in the temperature distribution due to the flow of the fluid to be measured can be reduced, and the detection accuracy of the physical property value detection unit can be improved.

Therefore, according to the present invention, it is possible to realize a flow rate measuring apparatus capable of reducing a change in output characteristics due to a change in physical properties of a fluid to be measured and measuring a flow rate of the fluid to be measured with high accuracy.

In the flow rate measuring device according to the present invention, it is preferable that the sub-flow path portion further includes a flow rate detection flow path in which the flow rate detecting portion is disposed, and one end of the flow rate detection flow path communicates with the first inlet and the other end communicates with the first outlet, and the fluid to be measured flowing in from the first inlet is branched into the physical property value detection flow path and the flow rate detection flow path.

In the above configuration, the sub-flow path portion further includes a flow rate detection flow path in which the flow rate detection portion is disposed, and the fluid to be measured that has flowed in from the inflow port is branched into the physical property value detection flow path and the flow rate detection flow path. By branching the fluid to be measured, which flows in from the same inlet port, to the physical property value detection channel and the flow rate detection channel in this manner, the physical property value detection unit and the flow rate measurement unit can detect the physical property value or the flow rate based on the fluid to be measured having the same conditions such as temperature and concentration. Further, for example, by adjusting the widths of the physical property value detection flow path and the flow rate detection unit, the flow rates of the measurement target fluids flowing through the physical property value detection flow path and the flow rate detection unit can be individually controlled.

Therefore, according to the above configuration, the measurement accuracy of the flow rate measurement device can be improved.

In the flow rate measuring device according to the present invention, the flow rate detecting unit and the property value detecting unit may have a bent shape between the first inlet and the first outlet,

the sub-passage portion further includes a dust separation passage having one end communicating with the first inlet and the other end communicating with the first outlet, and linearly connecting the first inlet and the first outlet.

In the flow rate measuring device according to the present invention, the flow rate detecting unit and the property value detecting unit have a bent shape between the first inlet and the first outlet, so that the flow rate detecting unit and the property value detecting unit can be clearly separated from each other, and the fluid to be measured flowing from the first inlet can be more reliably branched to the property value detecting flow path and the flow rate detecting flow path.

In the flow rate measuring device according to the present invention, the auxiliary flow path portion further includes a dust separation flow path having one end communicating with the first inlet and the other end communicating with the first outlet, and connecting the first inlet and the first outlet linearly. In the dust separation flow path having the other end communicating with the first outlet and connecting the first inlet and the first outlet linearly, the fluid to be measured flowing in from the first inlet flows at a flow speed higher than that of the property value detection flow path and the flow rate detection flow path. This is because the fluid to be measured, which has flowed in from the first inlet, can flow out more directly from the first outlet and return to the main channel.

Therefore, dust contained in the fluid to be measured that flows in from the first inlet port flows through the dust separation channel preferentially. As a result, the amount of dust flowing through the physical property value detection flow path and the flow rate detection flow path can be reduced, and the amount of dust adhering to the flow rate detection unit and the physical property value detection unit can be reduced.

Therefore, according to the above configuration, the reliability of the flow rate detecting unit and the physical property value detecting unit can be improved.

In the flow rate measuring device according to the present invention, it is preferable that the physical property value detection flow path is provided in the flow rate detection flow path, and a part of the fluid to be measured flowing through the flow rate detection flow path is caused to flow into the physical property value detection flow path.

In the above configuration, the physical property value detection flow path is provided in the flow rate detection flow path, and a part of the fluid to be measured flowing through the flow rate detection flow path is caused to flow into the physical property value detection flow path. Therefore, the physical property value detection unit and the flow rate measurement unit can detect the physical property value and the flow rate based on the fluid to be measured having the same conditions such as temperature and concentration, and the proportion of the sub-flow path portion occupied by the physical property value detection unit and the flow rate measurement unit can be reduced.

Therefore, according to the above configuration, the measurement accuracy of the flow rate measurement device can be improved, and the flow rate measurement device can be downsized.

In the flow rate measuring device according to the present invention, it is preferable that the sub-flow path portion further includes a flow rate detection flow path in which the flow rate detection portion is disposed, one end of the flow rate detection flow path communicates with a second inlet opening in the main flow path, and the other end of the flow rate detection flow path communicates with a second outlet opening in the main flow path.

In the above configuration, the secondary flow path portion further includes a flow rate detection flow path having one end communicating with the second inlet opening in the main flow path and the other end communicating with the second outlet opening in the main flow path. That is, the sub-channel section has the physical property value detection channel and the flow rate detection channel as two independent sub-channels. Therefore, by adjusting the widths of the physical property value detection flow path and the flow rate detection unit, the flow rates of the measurement target fluids flowing through the physical property value detection flow path and the flow rate detection unit can be individually controlled.

Therefore, according to the above configuration, the physical property value detection flow path and the flow rate detection flow path can be provided at arbitrary positions of the main flow path, and the measurement accuracy of the flow rate measurement device can be improved.

In the flow rate measuring device according to the present invention, it is preferable that the flow rate detecting unit is disposed in the main flow path.

In the above configuration, the physical property value detection unit is disposed in the physical property value detection flow path, and the flow rate detection unit is disposed in the main flow path. Therefore, the flow rate of the fluid to be measured flowing through the physical property value detection channel and the flow rate detection unit can be controlled independently.

In the flow rate measuring device according to the present invention, the heating section is preferably arranged such that a longitudinal direction of the heating section is along a flow direction of the fluid to be measured.

In the above configuration, since the longitudinal direction of the heating portion is arranged along the flow direction of the measurement target fluid, the heating portion can heat the measurement target fluid over a wide range in the flow direction of the measurement target fluid. Therefore, even when the temperature distribution is shifted to the downstream side by the flow of the fluid to be measured, the change in the output characteristic of the temperature detection unit can be reduced.

In the flow rate measuring device according to the present invention, it is preferable that the temperature detecting unit is disposed along a flow direction of the fluid to be measured in a longitudinal direction of the temperature detecting unit.

In the above configuration, since the longitudinal direction of the temperature detection unit is arranged along the flow direction of the fluid to be measured, the temperature detection unit can detect the temperature over a wide range in the flow direction of the fluid to be measured. Therefore, even when the temperature distribution is shifted to the downstream side by the flow of the fluid to be measured, the change in the output characteristic of the temperature detection unit can be reduced.

Therefore, according to the above configuration, the influence of the change in the temperature distribution caused by the flow of the fluid to be measured can be reduced, and the detection accuracy of the physical property value detection unit can be improved.

Effect of the utility model

As described above, the flow rate measuring device of the present invention includes: a flow rate detection unit for detecting a flow rate of a fluid to be measured flowing through the main flow path; a physical property value detection unit having a heating unit that heats a fluid to be measured and a temperature detection unit that detects a temperature of the fluid to be measured, and detecting a physical property value of the fluid to be measured; a sub-channel section having a property value detection channel having one end communicating with a first inlet opening in the main channel and the other end communicating with a first outlet opening in the main channel, and in which the property value detection section is disposed; a flow rate correction unit that corrects the flow rate of the fluid to be measured calculated based on the detection signal output from the flow rate detection unit, using the physical property value of the fluid to be measured calculated based on the detection signal output from the physical property value detection unit; the heating unit and the temperature detection unit are arranged in a direction orthogonal to the flow direction of the fluid to be measured, and the flow rate detection unit is arranged at a position other than the physical property value detection flow path.

Therefore, according to the present invention, the following effects are achieved: provided is a flow rate measurement device capable of accurately measuring the flow rate of a fluid to be measured while reducing changes in output characteristics caused by changes in the physical properties of the fluid to be measured.

Drawings

Fig. 1 (a) is an exploded perspective view showing a flow rate measuring device according to a first embodiment, and fig. 1 (b) is a perspective view showing the flow rate measuring device shown in fig. 1 (a);

fig. 2 is a perspective view showing the sub-flow path portion shown in fig. 1;

fig. 3 (a) is a plan view showing a schematic configuration of the physical property value sensor shown in fig. 2, and fig. 3 (b) is a plan view showing a schematic configuration of the flow rate sensor shown in fig. 2;

fig. 4 is a schematic view for explaining the flow rate of the fluid to be measured branched into the physical property value detection flow path and the flow rate detection flow path shown in fig. 2;

FIG. 5 is a graph showing the relationship between the output values of the property value sensor and the flow rate sensor shown in FIG. 4 and the flow rate;

fig. 6 is a block diagram showing a main configuration of a control unit provided in the flow rate measurement device shown in fig. 1;

fig. 7 is a flowchart showing a flow of processing of the control unit shown in fig. 6;

FIG. 8 is a plan view showing an example in which a dust separation flow path is further provided in the sub-flow path portion shown in FIG. 4;

fig. 9 (a) to (d) are plan views showing modifications of the physical property value detection flow path and the flow rate detection flow path formed on the upper surface of the sub-flow path portion shown in fig. 4;

fig. 10 is a plan view schematically showing a structure of a modification of the physical property value sensor shown in fig. 3 (a);

fig. 11 (a) is a perspective view showing a flow rate measurement device according to the second embodiment, fig. 11 (b) is a cross-sectional view showing the flow rate measurement device shown in fig. 11 (a), and fig. 11 (c) is a plan view showing a sub-flow path portion shown in fig. 11 (a);

fig. 12 (a) is a perspective view showing a flow rate measuring device according to the third embodiment, and fig. 12 (b) is a plan view showing a sub-flow path portion shown in fig. 12 (a);

fig. 13 (a) is a perspective view showing a flow rate measuring device according to the fourth embodiment, fig. 13 (b) is a perspective view showing a sub-flow path portion shown in fig. 13 (a), and fig. 13 (c) is a plan view showing the sub-flow path portion shown in fig. 13 (a);

fig. 14 is a schematic diagram for explaining a change in temperature distribution in the thermal type flow rate measurement device, in which fig. 14 (a) shows a temperature distribution in a state where a measurement target fluid does not flow, and fig. 14 (b) shows a temperature distribution in a state where the measurement target fluid flows;

fig. 15 (a) and (b) are schematic diagrams showing temperature distributions when GasA and GasB having different physical property values flow through the flow channel at predetermined flow rates (L/min);

fig. 16 is a graph showing the relationship between the flow rates (L/min) of GasA and GasB and the output value (V) of the flow rate measuring device shown in fig. 15 (a) and (b);

fig. 17 is a plan view showing a structure of a micro flow sensor provided in a conventional flow rate measuring device;

fig. 18 is a perspective view showing an external appearance of a conventional flow rate measuring device.

Description of the reference numerals

1a flow rate measuring device;

3a secondary flow path part;

3a secondary flow path portion;

3b a sub-flow path part;

3c a secondary flow path portion;

7a physical property value sensor (physical property value detection unit);

8 a flow sensor (flow rate detection unit);

21a main flow path;

31a secondary flowpath;

31a secondary flow path;

31b a first sub flow path;

31B a second sub flow path;

31c a secondary flow path;

32 a physical property value detection flow path (physical property value detection flow path);

32b a physical property value detection channel (physical property value detection channel);

32c a physical property value detection flow path (physical property value detection flow path);

33 a flow rate detection flow path (flow rate detection flow path);

a flow rate detection flow path (flow rate detection flow path) 33B;

33c a flow rate detection flow path (flow rate detection flow path);

34 an inflow channel;

34A flow inlet (first flow inlet);

35 outflow channel;

35A outflow port (first outflow port);

36 a physical property value detection region;

54 a flow rate correction unit;

71 a micro heater (heating part);

72 a first physical property value thermopile (temperature detecting unit);

73 second property value thermopile (temperature detection unit).

Detailed Description

[ first embodiment ]

A first embodiment of a flow rate measuring device according to the present invention will be described below with reference to fig. 1 to 10. In the present embodiment, a case will be described where the flow rate of a fluid such as a gas (hereinafter, referred to as a fluid to be measured) is measured using the flow rate measuring apparatus of the present invention.

(1) Structure of flow rate measuring device

First, the structure of the flow rate measuring device of the present embodiment will be described with reference to fig. 1 to 4.

Fig. 1 (a) is an exploded perspective view showing a flow rate measurement device 1 according to the present embodiment, and fig. 1 (b) is a perspective view showing the flow rate measurement device 1 shown in fig. 1 (a).

As shown in fig. 1 (a) and (b), the flow rate measuring device 1 includes a main flow path portion 2 in which a main flow path 21 is formed, a sub-flow path portion 3 in which a sub-flow path 31 is formed, a seal 4, a circuit board 5, and a cover 6.

The main flow path section 2 is a tubular member in which a main flow path 21 penetrating in the longitudinal direction is formed. An inlet (first inlet) 34A is formed on the upstream side and an outlet (first outlet) 35A is formed on the downstream side with respect to the flow direction O of the fluid to be measured on the inner peripheral surface of the main channel portion 2.

In the present embodiment, the axial length of the main channel portion 2 is about 50mm, the diameter of the inner peripheral surface of the main channel portion 2 (the diameter of the main channel 21) is about 20mm, and the diameter of the outer peripheral surface of the main channel portion 2 is about 24 mm.

The sub-flow path portion 3 is provided in the main flow path portion 2, and a sub-flow path 31 is formed in the inside and on the upper surface thereof. The sub-channel 31 communicates with the inlet 34A, and the other end communicates with the outlet 35A. In the flow rate measuring apparatus 1, the sub-channel 31 is composed of an inflow channel 34, a physical property value detection channel 32, a flow rate detection channel 33, and an outflow channel 35.

The inflow channel 34 is a channel for flowing the fluid to be measured flowing through the main channel 21 and branching the fluid to the physical property value detection channel 32 and the flow rate detection channel 33. The inflow channel 34 is formed so as to penetrate the sub-channel 3 in a direction perpendicular to the main channel 21, and has one end communicating with the inflow port 34A and the other end opening on the upper surface of the main channel 2 and communicating with the property value detection channel 32 and the flow rate detection channel 33. This allows a part of the fluid to be measured flowing through the main channel 21 to be branched into the physical property value detection channel 32 and the flow rate detection channel 33 via the inflow channel 34.

The physical property value detection flow path (physical property value detection flow path) 32 is a substantially コ -shaped flow path formed on the upper surface of the secondary flow path portion 3 and extending in a direction parallel to the main flow path 21. The physical property value detection flow path 32 has a physical property value detection region 36 in a portion extending in the longitudinal direction (direction parallel to the main flow path 21), and the physical property value sensor 7 for detecting the physical property value of the fluid to be measured is disposed in the physical property value detection region 36. One end of the physical property value detection channel 32 communicates with the inlet 34A via the inflow channel 34, and the other end communicates with the outlet 35A via the outflow channel 35.

The flow rate detection flow path (flow rate detection flow path) 33 is a substantially コ -shaped flow path formed on the upper surface of the secondary flow path portion 3 and extending in a direction parallel to the main flow path 21. The flow rate detection flow path 33 has a flow rate detection region 37 at a portion extending in the longitudinal direction (direction parallel to the main flow path 21), and a flow rate sensor 8 for detecting the flow rate of the fluid to be measured is disposed in the flow rate detection region 37. One end of the flow rate detection channel 33 communicates with the inlet 34A via the inlet channel 34, and the other end communicates with the outlet 35A via the outlet channel 35.

In the drawings, for convenience of explanation, the physical property value sensor 7 and the flow rate sensor 8 are shown in a state separated from the circuit board 5, but the physical property value sensor 7 and the flow rate sensor 8 are disposed in the physical property value detection region 36 or the flow rate detection region 37 in a state attached to the circuit board 5.

The outflow channel 35 is a channel for flowing the fluid to be measured, which has passed through the physical property value detection channel 32 and the flow rate detection channel 33, out to the main channel 21. The outflow channel 35 is formed so as to penetrate the sub-channel 3 in a direction perpendicular to the main channel 21, and has one end communicating with the outflow port 35A and the other end opening on the upper surface of the main channel 2 and communicating with the property value detection channel 32 and the flow rate detection channel 33. This enables the fluid to be measured that has passed through the physical property value detection flow path 32 and the flow rate detection flow path 33 to flow out to the main flow path 21 through the outflow flow path 35.

By branching the fluid to be measured, which flows in from the same inlet 34A, to the physical property value detection flow path 32 and the flow rate detection flow path 33 in this way, the physical property value sensor 7 and the flow rate sensor 8 can detect a physical property value or a flow rate based on the fluid to be measured having the same conditions such as temperature and concentration. Therefore, the measurement accuracy of the flow rate measurement device 1 can be improved.

In the flow rate measuring apparatus 1, after the sealing member 4 is fitted into the sub-channel 3, the circuit board 5 is disposed, and the circuit board 5 is fixed to the sub-channel 3 by the cover 6, thereby ensuring airtightness inside the sub-channel 3.

Fig. 2 is a perspective view showing the sub-channel 3 shown in fig. 1 (a). As shown in fig. 2, one end of the approximately コ shape of the physical property value detection flow path 32 communicates with the inflow flow path 34, and the other end communicates with the outflow flow path 35. Similarly, one end of the flow rate detection flow path 33 having a substantially コ shape communicates with the inflow flow path 34, and the other end communicates with the outflow flow path 35.

The physical property value detection flow path 32 and the flow rate detection flow path 33 are also communicated with each other at both ends, and the physical property value detection flow path 32 and the flow rate detection flow path 33 form a rectangular flow path on the upper surface of the sub-flow path portion 3.

In the flow rate measuring apparatus 1, the physical property value detection region 36 and the flow rate detection region 37 are both square in shape when viewed from a direction perpendicular to the upper surface of the secondary flow path portion 3, and are formed at positions symmetrical to a straight line connecting the inflow flow path 34 and the outflow flow path 35.

In the present embodiment, the physical property value detection region 36 and the flow rate detection region 37 each have a side length of about 4 mm.

In the present embodiment, the physical property value detection region 36 and the flow rate detection region 37 are formed in a square shape, but the present invention is not limited thereto. The physical property value detection region 36 and the flow rate detection region 37 may have any shape as long as the physical property value sensor 7 or the flow rate sensor 8 can be arranged, and are determined according to the shape of the arranged physical property value sensor 7 and the flow rate sensor 8.

Therefore, for example, when the physical property value sensor 7 is smaller in size than the physical property value detection channel 32, the width of the physical property value detection region 36 can be made equal to the width of the physical property value detection channel 32. In this case, the portion extending in the longitudinal direction of the physical property value detection channel 32 is formed in a linear shape. The same applies to the flow rate detection area 37.

Fig. 3 (a) is a plan view showing a schematic configuration of the property value sensor 7 shown in fig. 2, and fig. 3 (b) is a plan view showing a schematic configuration of the flow rate sensor 8 shown in fig. 2.

As shown in fig. 3 (a), the property value sensor 7 includes a micro heater (heating unit) 71 that heats a fluid to be measured, a first property value thermopile (temperature detecting unit) 72 that detects the temperature of the fluid to be measured, and a second property value thermopile (temperature detecting unit) 73. The micro-heater 71, the first property value thermopile 72, and the second property value thermopile 73 are arranged in the property value detection region 36 in a direction orthogonal to the flow direction of the fluid to be measured.

The first property value thermopile 72 and the second property value thermopile 73 are arranged bilaterally symmetrically with the micro-heater 71 interposed therebetween, and the temperatures of symmetrical positions on both sides of the micro-heater 71 are detected.

Here, since the temperature distribution of the fluid to be measured is shifted to the downstream side due to the flow of the fluid, the change in the temperature distribution in the direction orthogonal to the flow direction is smaller than the change in the temperature distribution in the flow direction of the fluid to be measured. Therefore, by arranging the first property value thermopile 72, the micro-heater 71, and the second property value thermopile 73 in this order in a direction orthogonal to the flow direction of the measurement target fluid, it is possible to reduce the change in the output characteristics of the first property value thermopile 72 and the second property value thermopile 73 due to the change in the temperature distribution. Therefore, the influence of the change in the temperature distribution due to the flow of the fluid to be measured can be reduced, and the detection accuracy of the physical property value sensor 7 can be improved.

Further, since the longitudinal direction of the micro-heater 71 is arranged along the flow direction of the fluid to be measured, the micro-heater 71 can heat the fluid to be measured over a wide range in the flow direction of the fluid to be measured. Therefore, even when the temperature distribution is shifted to the downstream side by the flow of the measurement target fluid, the change in the output characteristics of the first property value thermopile 72 and the second property value thermopile 73 can be reduced. Therefore, the influence of the change in the temperature distribution due to the flow of the fluid to be measured can be reduced, and the detection accuracy of the physical property value sensor 7 can be improved.

Further, since the first property value thermopile 72 and the second property value thermopile 73 are arranged in the longitudinal direction along the flow direction of the measurement target fluid, the first property value thermopile 72 and the second property value thermopile 73 can detect temperatures over a wide range in the flow direction of the measurement target fluid. Therefore, even when the temperature distribution is shifted to the downstream side by the flow of the measurement target fluid, the output characteristic changes of the first property value thermopile 72 and the second property value thermopile 73 can be reduced. Therefore, the influence of the change in the temperature distribution due to the flow of the fluid to be measured can be reduced, and the detection accuracy of the physical property value sensor 7 can be improved.

On the other hand, as shown in fig. 3 (b), the flow sensor 8 includes a micro-heater 81 that heats the fluid to be measured, a first flow rate thermopile 82 and a second flow rate thermopile 83 that detect the temperature of the fluid to be measured. The micro-heater 81, the first flow rate thermopile 82, and the second flow rate thermopile 83 are arranged in the flow rate detection region 37 in the flow direction of the measurement target fluid.

The first flow rate thermopile 82 and the second flow rate thermopile 83 are arranged such that the first flow rate thermopile 82 is disposed on the upstream side of the micro heater 81, the second flow rate thermopile 83 is disposed on the downstream side of the micro heater 81, and the temperatures of the positions symmetrical with respect to the micro heater 81 are detected.

In the flow rate measuring apparatus 1, the physical property value sensor 7 and the flow rate sensor 8 have substantially the same structure, and are arranged at different arrangement angles of 90 ° with respect to the flow direction of the fluid to be measured. This allows the sensor having the same configuration to function as the physical property value sensor 7 or the flow sensor 8, and thus the manufacturing cost of the flow rate measuring device 1 can be reduced.

Here, in the flow rate measuring apparatus 1, the physical property value detection flow path 32 and the flow rate detection flow path 33 have different widths of flow paths extending in the longitudinal direction, and the width of the flow path in which the physical property value sensor 7 is disposed in the physical property value detection flow path 32 is narrower than the width of the flow path in which the flow rate sensor 8 is disposed in the flow rate detection flow path 33. Thus, in the flow rate measuring apparatus 1, the flow rates of the measurement target fluids branched into the physical property value detection flow path 32 and the flow rate detection flow path 33 are individually controlled.

Fig. 4 is a schematic diagram for explaining the flow rate of the fluid to be measured branched into the physical property value detection flow path 32 and the flow rate detection flow path 33 shown in fig. 2. As shown in fig. 4, in the present embodiment, the physical property value detection flow path 32 and the flow rate detection flow path 33 are set to have widths such that the fluid to be measured having the flow rate P is branched in the physical property value detection flow path 32 and the fluid to be measured having the flow rate Q is branched in the flow rate detection flow path 33.

The values of the flow rate P and the flow rate Q vary according to the flow rate of the fluid to be measured flowing through the main channel 21, and in a normal use mode, the widths of the physical property value detection channel 32 and the flow rate detection channel 33 are set so that the flow rate P is within the detection range of the physical property value sensor 7 and the flow rate Q is within the detection range of the flow rate sensor 8, respectively.

In the present embodiment, the physical property value detection channel 32 has a width of about 0.4mm, and the flow rate detection channel 33 has a width of about 0.8 mm.

In this way, in the flow rate measuring apparatus 1, the flow rates of the measurement target fluids branched to the physical property value detection flow path 32 and the flow rate detection flow path 33 can be individually controlled by adjusting the widths of the physical property value detection flow path 32 and the flow rate detection flow path 33. Therefore, the flow rate of the fluid to be measured flowing through the property value detection region 36 can be controlled according to the detection range of the property value sensor 7, and the flow rate of the fluid to be measured flowing through the flow rate detection region 37 can be controlled according to the detection range of the flow rate sensor 8.

Therefore, the physical property value sensor 7 can detect the physical property value of the fluid to be measured at the optimum flow rate according to the specific detection range, and the detection accuracy of the physical property value sensor 7 can be improved.

Similarly, the flow rate sensor 8 can detect the flow rate of the fluid to be measured at the optimum flow rate corresponding to the specific detection range, and therefore, the detection accuracy of the flow rate sensor 8 can be improved.

Fig. 5 is a graph showing a relationship between the output values of the property value sensor 7 and the flow rate sensor 8 shown in fig. 4 and the flow rate. In fig. 5, the horizontal axis defines a flow rate (%), the vertical axis defines an output value (%) of each sensor, the maximum flow rate in the detection ranges of the property value sensor 7 and the flow rate sensor 8 is defined as 100%, and the sensor output value at the time of the maximum flow rate is defined as 100%.

As shown in fig. 5, the output value of the flow rate sensor 8 increases as the flow rate of the measurement target fluid flowing through the flow rate detection region 37 increases, whereas the output value of the property value sensor 7 is constant without being affected by the change in the flow rate of the measurement target fluid flowing through the property value detection region 36.

Thus, according to the flow rate measurement device 1, the physical property value sensor 7 can detect the physical property value of the measurement target fluid without being affected by the change in the flow rate of the measurement target fluid, and therefore, the accuracy of detecting the physical property value can be improved.

(2) Constitution of control part

Next, the configuration of the control unit included in the flow rate measuring apparatus 1 will be described with reference to fig. 6. Fig. 6 is a block diagram showing a main configuration of the control unit 51 provided in the flow rate measurement device 1 shown in fig. 1. As shown in fig. 6, the control unit 51 includes a flow rate calculation unit 52, a physical property value calculation unit 53, and a flow rate correction unit 54. The property value calculating unit 53 is connected to the first property value thermopile 72 and the second property value thermopile 73. The flow rate calculating unit 52 is connected to the first flow rate thermopile 82 and the second flow rate thermopile 83.

The flow rate calculation unit 52 calculates the flow rate of the fluid to be measured based on the temperature detection signals output from the first and second

flow rate thermopiles

82 and 83. Specifically, the flow rate calculation unit 52 calculates a difference between the temperature detection signal output from the first flow rate thermopile 82 and the temperature detection signal output from the second flow rate thermopile 83, and calculates the flow rate of the fluid to be measured based on the difference between the temperature detection signals. Then, the flow rate calculation unit 52 outputs the calculated flow rate of the fluid to be measured to the flow rate correction unit 54.

The property value calculation unit 53 calculates the property value of the measurement target fluid based on the temperature detection signals output from the first property value thermopile 72 and the second property value thermopile 73. Specifically, the physical property value calculation unit 53 calculates a physical property value (for example, a thermal diffusion constant) determined by thermal conductivity, thermal diffusion, specific heat, or the like based on an average value of temperature detection signals output from the first physical property value thermopile 72 and the second physical property value thermopile 73. The physical property value calculation unit 53 outputs the calculated physical property value of the fluid to be measured to the flow rate correction unit 54.

The flow rate correction unit 54 corrects the flow rate of the fluid to be measured output from the flow rate calculation unit 52, using the physical property value of the fluid to be measured output from the physical property value calculation unit 53. Specifically, when the physical property value of the measurement target fluid is output from the physical property value calculation unit 53, the flow rate correction unit 54 corrects the flow rate of the measurement target fluid output from the flow rate calculation unit 52 using the physical property value, and calculates the corrected flow rate.

(3) Processing of flow rate measuring apparatus

Next, a flow of processing by the control unit 51 provided in the flow rate measuring apparatus 1 will be described with reference to fig. 7. Fig. 7 is a flowchart showing a flow of processing of the control unit 51 shown in fig. 6.

As shown in fig. 7, when the temperature detection signals are output from the first flow rate thermopile 82 and the second flow rate thermopile 83, the flow rate calculation unit 52 calculates the flow rate of the fluid to be measured based on the two temperature detection signals (S1).

Specifically, the flow rate calculation portion 52 calculates a difference between the temperature detection signal output from the first flow rate thermopile 82 and the temperature detection signal output from the second flow rate thermopile 83. The flow rate calculation unit 52 calculates the flow rate of the fluid to be measured based on the calculated difference in the temperature detection signals.

A known method can be used to calculate the flow rate of the measurement target fluid based on the temperature detection signals output from the first and second

flow rate thermopiles

82 and 83. The flow rate calculation unit 52 outputs the calculated flow rate of the fluid to be measured to the flow rate correction unit 54.

When the temperature detection signals are output from the first property value thermopile 72 and the second property value thermopile 73, the property value calculation unit 53 calculates the property value of the measurement target fluid based on the average value of the two temperature detection signals (S2).

Since the speed of heat conducted in the fluid to be measured corresponds to a physical property value such as a thermal diffusion constant determined by thermal conductivity, thermal diffusion, specific heat, or the like, the thermal diffusion constant can be obtained by detecting a temperature difference among the micro-heater 71, the first physical property value thermopile 72, and the second physical property value thermopile 73. For example, the greater the temperature difference between the micro-heater 71 and the first property-value thermopile 72 and the second property-value thermopile 73, the smaller the thermal diffusion constant (thermal conductivity).

By utilizing such a property, the temperature of the fluid to be measured is detected by the first property value thermopile 72 and the second property value thermopile 73 arranged in the direction orthogonal to the flow direction of the fluid to be measured, and the property value of the fluid to be measured can be calculated.

Here, in the flow rate measuring apparatus 1, since the flow rate of the fluid to be measured flowing through the property value detection region 36 is controlled in accordance with the detection range of the property value sensor 7, the first property value thermopile 72 and the second property value thermopile 73 can detect the heat emitted from the micro heater 71 without being affected by the flow rate of the fluid to be measured.

Therefore, the first property value thermopile 72 and the second property value thermopile 73 can output the temperature detection signal to the property value calculation unit 53 while maintaining a constant output characteristic, and therefore the property value calculation unit 53 can calculate the property value with high accuracy. The physical property value calculation unit 53 outputs the calculated physical property value of the fluid to be measured to the flow rate correction unit 54.

Next, when the physical property value of the fluid to be measured is output from the physical property value calculation unit 53, the flow rate correction unit 54 corrects the flow rate of the fluid to be measured output from the flow rate calculation unit 52 using the physical property value, and calculates a corrected flow rate (S3). Specifically, the flow rate correction unit 54 calculates the corrected flow rate using the following calculation formula (2).

[ formula 2]

Equation (2) is calculated by multiplying the corrected flow output value by the coefficient … corresponding to the physical property value

In this way, in the flow rate measuring apparatus 1, since the output characteristic of the property value sensor 7 is not affected by the flow rate of the fluid to be measured, the flow rate correction unit 54 can correct the flow rate of the fluid to be measured output from the flow rate calculation unit 52 without performing correction according to the flow rate with respect to the property value of the fluid to be measured output from the property value calculation unit 53 as in the conventional art.

Therefore, according to the flow rate measurement device 1, the flow rate of the fluid to be measured detected by the flow rate sensor 8 can be appropriately corrected based on the physical value detected by the physical value sensor 7, and therefore the flow rate of the fluid to be measured can be accurately measured.

(4) Summary of the invention

As described above, the flow rate measurement device 1 of the present embodiment includes: a flow rate sensor 8 for detecting a flow rate of the fluid to be measured flowing through the main channel 21; a physical property value sensor 7 which has a micro heater 71 for heating a fluid to be measured, and a first physical property value thermopile 72 and a second physical property value thermopile 73 for detecting a temperature of the fluid to be measured, and which detects a physical property value of the fluid to be measured; a sub-channel section 3 having a physical property value detection channel 32 having one end communicating with an inlet 34A opened in the main channel 21 and the other end communicating with an outlet 35A opened in the main channel 21, and in which a physical property value sensor 7 is disposed; a flow rate correction unit 54 that corrects the flow rate of the fluid to be measured calculated based on the detection signal output from the flow rate sensor 8, using the physical property value of the fluid to be measured calculated based on the detection signal output from the physical property value sensor 7; the micro-heater 71, the first property value thermopile 72, and the second property value thermopile 73 are arranged in a direction orthogonal to the flow direction of the fluid to be measured, and the flow rate sensor 8 is arranged at a position other than the property value detection flow channel 32.

In the flow rate measuring apparatus 1, the physical property value sensor 7 is disposed in the physical property value detection flow path 32, and the flow rate sensor is disposed in the flow rate detection flow path 33. Therefore, for example, by controlling the flow rate of the measurement target fluid flowing through the physical property value detection flow path 32 by adjusting the width of the physical property value detection flow path 32, it is possible to suppress the output characteristic of the physical property value sensor 7 from changing due to the influence of the flow rate, and it is possible to efficiently suppress the occurrence of turbulent flow due to the flow of the measurement target fluid.

Therefore, according to the flow rate measurement device 1, the flow rate correction unit 54 can accurately correct the flow rate of the fluid to be measured calculated based on the detection signal output from the flow rate sensor 8, using the high-accuracy physical property value calculated based on the detection signal output from the physical property value sensor 7.

In the flow rate measuring apparatus 1, the physical property value sensor 7 is disposed in the physical property value detection channel 32 having one end communicating with the inlet 34A opened in the main channel 21 and the other end communicating with the outlet 35A opened in the main channel 21. Therefore, the fluid to be measured flows from the inlet 34A to the outlet 35A without being stagnated, and thus the fluid to be measured existing in the vicinity of the property value sensor 7 can be efficiently replaced.

Therefore, according to the flow rate measurement device 1, even when the physical property value of the measurement target fluid flowing through the main channel 21 changes, the flow rate of the measurement target fluid can be accurately corrected based on the appropriate physical property value.

Further, since the temperature distribution of the fluid to be measured is shifted to the downstream side due to the flow of the fluid to be measured, the change in the temperature distribution in the direction orthogonal to the flow direction is smaller than the change in the temperature distribution in the flow direction of the fluid to be measured, and therefore, by arranging the first property value thermopile 72, the micro-heater 71, and the second property value thermopile 73 in the direction orthogonal to the flow direction of the fluid to be measured, the change in the output characteristics of the first property value thermopile 72 and the second property value thermopile 73 due to the change in the temperature distribution can be reduced. Therefore, the influence of the change in the temperature distribution due to the flow of the fluid to be measured can be reduced, and the detection accuracy of the physical property value sensor 7 can be improved.

Therefore, according to the present embodiment, it is possible to realize a flow rate measurement device 1 capable of measuring the flow rate of a fluid to be measured with high accuracy while reducing a change in output characteristics due to a change in the physical properties of the fluid to be measured.

(5) Modification example

Next, a modified example of the flow rate measurement device 1 according to the present embodiment will be described with reference to fig. 8 to 10.

(5-1) modification 1

In the present embodiment, as shown in fig. 4, the physical property value detection flow path 32 and the flow rate detection flow path 33 are bent in an approximately コ shape, and only both ends of these two flow paths are communicated with the inflow flow path 34 and the outflow flow path 35.

Fig. 8 is a plan view showing a modification of the flow path formed on the upper surface of the secondary flow path portion 3 shown in fig. 4. In modification 1, in addition to the physical property value detection flow path 32 and the flow rate detection flow path 33 formed by bending in an approximately コ shape, a dust separation flow path 39 having both ends formed linearly in communication with the inflow flow path 34 and the outflow flow path 35 is provided.

Here, in the dust separation flow path 39 formed linearly and communicating with the inflow flow path 34 and the outflow flow path 35 at both ends, the fluid to be measured flowing in from the inflow flow path 34 flows at a higher flow velocity than the physical property value detection flow path 32 and the flow rate detection flow path 33. This is because the fluid to be measured that has flowed in from the inflow channel 34 can more directly flow out from the outflow channel 35 and return to the main channel 21.

In this case, the dust contained in the fluid to be measured that flows in from the inflow channel 34 preferentially flows through the dust separation channel 39. As a result, the amount of dust flowing through the property value detection flow path 32 and the flow rate detection flow path 33 can be reduced, and the amount of dust adhering to the flow rate sensor 8 and the property value sensor 7 can be reduced.

Therefore, according to the above configuration, it is possible to suppress a decrease in measurement accuracy due to the influence of dust on the measurement values of the flow rate sensor 8 and the property value sensor 7. Further, the reliability of the flow rate sensor 8 and the physical property value sensor 7 can be improved, and the life can be prolonged.

Here, the dust separation flow path 39 is a flow path having both ends communicating with the inflow flow path 34 and the outflow flow path 35 and formed linearly, but it is not necessarily formed linearly. The shape may be any shape as long as the degree of bending is smaller than the physical property value detection flow path 32 and the flow rate detection flow path 33, and the dust contained in the fluid to be measured flowing in from the inflow flow path 34 flows through the dust separation flow path 39 in preference to the physical property value detection flow path 32 and the flow rate detection flow path 33.

(5-2) modification 2

In the present embodiment, as shown in fig. 4, the structure in which both the physical property value detection flow path 32 and the flow rate detection flow path 33 are formed in the substantially コ shape has been described, but the present invention is not limited to this. The physical property value detection flow path 32 and the flow rate detection flow path 33 are not particularly limited in shape as long as they are set to a width that can control the flow rate of the fluid to be measured that passes through the physical property value detection region 36 and the flow rate detection region 37.

Fig. 9 (a) to (d) are plan views of modifications of the physical property value detection flow path 32 and the flow rate detection flow path 33 formed on the upper surface of the sub-flow path portion 3 shown in fig. 4.

As shown in fig. 9 (a), for example, the physical property value detection flow path 32 may be formed linearly, and the flow rate detection flow path 33 may be formed in a substantially コ shape.

As shown in fig. 9 (b) to 9 (d), the property value detection channel 32 may be formed so that the fluid to be measured flows into the property value detection region 36 from a direction orthogonal to the direction in which the fluid to be measured flows into the flow rate detection region 37.

In this case, since the physical property value sensor 7 and the flow rate sensor 8 can be arranged at the same angle, the step of mounting the physical property value sensor 7 and the flow rate sensor 8 on the circuit board 5 can be simplified in the manufacturing process of the flow rate measuring apparatus 1.

(5-3) modification 3

In the present embodiment, as shown in fig. 3 (a), a configuration has been described in which the property value sensor 7 includes a micro-heater 71 that heats a fluid to be measured, and a first property value thermopile 72 and a second property value thermopile 73 that detect the temperature of the fluid to be measured, and the first property value thermopile 72 and the second property value thermopile 73 are disposed in bilateral symmetry with the micro-heater 71 interposed therebetween, but the present invention is not limited thereto.

Fig. 10 is a plan view schematically showing a modified example of the property value sensor 7 shown in fig. 3 (a). As shown in fig. 10, the property value sensor 7a may be configured by the micro-heater 71 and the first property value thermopile 72 without the second property value thermopile 73.

In this way, the micro-heater 71 and the first physical property value thermopile 72 are arranged in a direction orthogonal to the flow direction of the measurement target fluid, whereby the physical property value sensor 7a can be realized.

[ second embodiment ]

Hereinafter, a second embodiment of the flow rate measuring device according to the present invention will be described with reference to fig. 11. Note that, the same members as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The flow rate measurement device of the present embodiment is different from the flow rate measurement device of the first embodiment in that the flow sensor is disposed in the main flow path.

Fig. 11 (a) is a perspective view showing a flow rate measurement device 1a according to the present embodiment, fig. 11 (b) is a cross-sectional view showing the flow rate measurement device 1a shown in fig. 11 (a), and fig. 11 (c) is a plan view showing a sub-flow path portion 3a shown in fig. 11 (a).

As shown in fig. 11 (a) to 11 (c), in the flow rate measuring device 1a, an opening 37A is formed between the inlet 34A and the outlet 35A on the inner peripheral surface of the main channel portion 2 a.

A groove-shaped flow rate detection region 37A in which the flow rate sensor 8 is disposed is formed inside the sub-flow passage portion 3a, and the flow rate detection region 37A communicates with the opening 37A. Therefore, the fluid to be measured flowing through the main channel 21a via the opening 37A flows into the flow rate detection region 37A, and the flow rate thereof is detected by the flow rate sensor 8.

By controlling and adjusting the size of the opening 37A, the flow rate of the fluid to be measured flowing from the main channel 21a into the flow rate detection region 37A can be controlled.

The sub-channel 31a includes an inflow channel 34, a physical property value detection channel 32, and an outflow channel 35, the physical property value detection channel 32 includes a physical property value detection region 36 in a channel extending in the longitudinal direction, and the physical property value sensor 7 for detecting the physical property value of the fluid to be measured is disposed in the physical property value detection region 36.

In this way, in the flow rate measuring apparatus 1a, the property value sensor 7 is disposed in the sub-channel 31a, and the flow rate sensor 8 is disposed in the main channel 21 a. Therefore, in the flow rate measuring apparatus 1a, the flow rate corresponding to the detection range of the property value sensor 7 can be controlled.

Therefore, according to the present embodiment, it is possible to realize the flow rate measurement device 1a capable of reducing the change in the output characteristics due to the change in the physical property of the fluid to be measured and measuring the flow rate of the fluid to be measured with high accuracy.

[ third embodiment ]

A third embodiment of the flow rate measuring device according to the present invention will be described below with reference to fig. 12. The same members as those in the first and second embodiments are denoted by the same reference numerals, and descriptions thereof are omitted.

The flow rate measurement device of the present embodiment is different from the flow rate measurement devices of the first and second embodiments in that two independent sub-flow paths are provided.

Fig. 12 (a) is a perspective view showing a flow rate measuring device 1c according to the present embodiment, and fig. 12 (b) is a plan view showing the sub-flow path portion 3 shown in fig. 12 (a).

As shown in fig. 12 (a) and 12 (B), in the flow rate measuring apparatus 1c, the sub-passage portion 3B has a first sub-passage 31B and a second sub-passage 31B formed therein and on the upper surface thereof.

The first sub-channel 31b includes an inflow channel 34b, a physical property value detection channel 32b, and an outflow channel 35b, the physical property value detection channel 32b has a physical property value detection region 36 in a channel extending in the longitudinal direction, and the physical property value sensor 7 for detecting the physical property value of the fluid to be measured is disposed in the physical property value detection region 36.

The second sub-flow path 31B includes an inflow flow path 34B, a flow rate detection flow path 33B, and an outflow flow path 35B, the flow rate detection flow path 33B includes a flow rate detection region 37 in a flow path extending in the longitudinal direction, and the flow rate sensor 8 for detecting the flow rate of the fluid to be measured is disposed in the flow rate detection region 37.

In this way, in the flow rate measuring apparatus 1B, the sub-channel section 3B has the first sub-channel 31B and the second sub-channel 31B as two independent sub-channels, the physical property value sensor 7 is disposed in the first sub-channel 31B, and the flow rate sensor 8 is disposed in the second sub-channel 31B. Therefore, according to the flow rate measurement device 1b, the flow rates corresponding to the detection ranges of the physical property value sensor 7 and the flow rate sensor 8 can be individually controlled.

Therefore, according to the present embodiment, it is possible to realize the flow rate measurement device 1b capable of reducing the change in the output characteristics due to the change in the physical property of the fluid to be measured and measuring the flow rate of the fluid to be measured with high accuracy.

[ fourth embodiment ]

A fourth embodiment of the flow rate measuring device according to the present invention will be described below with reference to fig. 13. The same members as those in the first to third embodiments are denoted by the same reference numerals, and descriptions thereof are omitted

The flow rate measuring device of the present embodiment is different from the flow rate measuring devices of the first to third embodiments in that the physical property value detection flow channel is formed in the flow rate detection flow channel.

Fig. 13 (a) is a perspective view showing a flow rate measuring device 1c according to the present embodiment, fig. 13 (b) is a perspective view showing a sub-flow path portion 3c shown in fig. 13 (a), and fig. 13 (c) is a plan view showing the sub-flow path portion 3c shown in fig. 13 (a).

As shown in fig. 13 a to 13 c, in the flow rate measuring apparatus 1c, the sub-channel section 3c has a sub-channel (first sub-channel) 31c formed therein and on the upper surface thereof.

The sub-channel 31c includes an inflow channel 34, a physical property value detection channel 32c, a flow rate detection channel 33c, and an outflow channel 35.

In the sub-flow path 31c, the physical property value detection flow path 32c is formed in a flow rate detection region 37c in the flow rate detection flow path 33c, and the flow rate sensor 8 is disposed on the upstream side and the physical property value sensor 7 is disposed on the downstream side with respect to the flow direction of the fluid to be measured.

Here, the physical property value detection flow path 32c is separated from the flow rate detection region 37c by a flow rate control member 40 for controlling the flow rate of the fluid to be measured, and the physical property value sensor 7 is disposed inside the flow rate control member 40.

The flow rate control member 40 is a member for controlling the flow rate of the fluid to be measured passing through the property value detection region 36c, and is composed of a first side wall portion 40a and a second side wall portion 40 b. The first side wall 40a and the second side wall 40b are both plate-like members having a substantially コ shape, and are arranged with a predetermined interval in a state where their respective end portions are opposed to each other.

Therefore, by controlling the distance between the first side wall 40a and the second side wall 40b, the flow rate of the fluid to be measured passing through the inside of the flow rate control member 40, that is, the physical property value detection region 36c can be adjusted.

In the flow rate measuring apparatus 1c, the sub-channel portion 3c includes the flow rate control member 40 in the sub-channel 31c, and the property value detection region 36c is provided in the flow rate control member 40, so that the property value detection region 36c can be provided at an arbitrary position in the sub-channel 31 c. Further, by providing the flow rate control member 40, the flow rate of the fluid to be measured passing through the property value detection region 36c can be easily controlled.

In this way, even if the flow rate detection flow path 33c is configured to have the physical property value detection flow path 32c formed therein, the flow rates corresponding to the detection ranges of the physical property value sensor 7 and the flow rate sensor 8 can be individually controlled.

Therefore, according to the present embodiment, it is possible to realize the flow rate measurement device 1c capable of measuring the flow rate of the fluid to be measured with high accuracy while reducing the change in the output characteristics due to the change in the physical property of the fluid to be measured.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope shown in the claims, and the present invention is intended to include embodiments obtained by appropriately combining technical means disclosed in different embodiments.

Industrial applicability

The utility model discloses a flow measurement device can be applicable to gas meter, combustion apparatus, automobile internal-combustion engine or fuel cell etc..

Claims

1. A flow rate measurement device is characterized by comprising:

a flow rate detection unit for detecting a flow rate of a fluid to be measured flowing through the main flow path;

a physical property value detection unit having a heating unit that heats a fluid to be measured and a temperature detection unit that detects a temperature of the fluid to be measured, and detecting a physical property value of the fluid to be measured;

a sub-channel section having a property value detection channel having one end communicating with a first inlet opening in the main channel and the other end communicating with a first outlet opening in the main channel, and in which the property value detection section is disposed;

the heating unit and the temperature detection unit are arranged in a direction orthogonal to the flow direction of the fluid to be measured,

the flow rate detecting unit is disposed at a position other than the physical property value detecting channel.

2. The flow rate measuring device according to claim 1,

the sub flow path portion further has a flow rate detection flow path in which the flow rate detection portion is disposed,

one end of the flow rate detection channel is communicated with the first inlet so that the fluid to be measured flowing in from the first inlet can be branched into the property value detection channel and the flow rate detection channel, and the other end of the flow rate detection channel is communicated with the first outlet.

3. The flow rate measuring device according to claim 2,

the flow rate detecting unit and the property value detecting unit have a bent shape between the first inlet and the first outlet,

4. The flow rate measuring device according to claim 2,

the physical property value detection flow path is provided in the flow rate detection flow path,

a part of the fluid to be measured flowing through the flow rate detection channel is caused to flow into the physical property value detection channel.

5. The flow rate measuring device according to claim 1,

one end of the flow rate detection flow path communicates with a second inlet opening in the main flow path, and the other end of the flow rate detection flow path communicates with a second outlet opening in the main flow path.

6. The flow rate measuring device according to claim 1,

the flow rate detection unit is disposed in the main flow path.

7. A flow rate measuring device according to any one of claims 1 to 6,

the heating portion is disposed such that a longitudinal direction thereof is along a flow direction of the fluid to be measured.

8. The flow rate measuring device according to any one of claims 1 to 6,

the temperature detection unit is disposed such that a longitudinal direction thereof is along a flow direction of the fluid to be measured.

9. The flow rate measuring device according to claim 7,