JP7419855B2 - Flow rate measurement device, flow rate measurement method, and flow rate measurement program - Google Patents

Description

The present invention relates to a flow rate measuring device, a flow rate measuring method, and a flow rate measuring program.

2. Description of the Related Art Conventionally, a flow rate measuring device has been proposed that includes a heating section and a temperature detecting section and measures the flow rate of a fluid to be measured. For example, in order to reduce changes in output characteristics due to changes in physical properties of the fluid to be measured, a flow rate measuring device has been proposed that includes a physical property value detection section for detecting physical property values of the fluid to be measured (Patent Document 1). Specifically, thermal conductivity (thermal diffusion constant) is determined by detecting the temperature difference between the microheater and the thermopile, and the flow rate measured by the sensor is corrected based on the thermal conductivity.

Furthermore, in order to improve the accuracy of flow rate measurement for fluids to be measured that have different thermal diffusivities, we prepared microheaters and thermopiles for detecting substances that were arranged in parallel in a direction perpendicular to the flow direction of the fluid to be measured. , a flow rate measuring device has been proposed that detects a difference in temperature of a fluid to be measured before and after changing the temperature of a microheater in two stages. In this technology, a characteristic value is acquired based on the difference in temperature of the fluid to be measured before and after changing the temperature of the microheater in two stages, and the flow rate of the fluid to be measured is corrected using the acquired characteristic value (Patent Document 2).

Japanese Patent Application Publication No. 2012-233776 Japanese Patent Application Publication No. 2017-129470

However, when the types of fluids to be measured increase, the characteristic values of the fluid to be measured may be changed due to the difference in temperature of the fluid to be measured detected by the thermopile before and after changing the temperature of the microheater in two stages. In cases where it is difficult to identify the physical properties of the fluid to be measured with sufficient accuracy just by acquiring the information, and it is difficult to sufficiently improve the accuracy of flow measurement for fluids to be measured with different thermal diffusivities. was there.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to further improve the accuracy of flow rate measurement for fluids to be measured having different thermal diffusivities.

The flow rate measuring device according to the present invention includes a flow rate detection section for detecting the flow rate of a fluid to be measured flowing through a main channel, a heating section for heating the fluid to be measured, and a temperature detection section for detecting the temperature of the fluid to be measured. and a characteristic value acquisition unit for acquiring characteristic values of the fluid to be measured, and a characteristic value of the fluid to be measured acquired by the characteristic value acquisition unit, based on the detection signal output from the flow rate detection unit. a flow rate correction section that corrects the flow rate of the fluid to be measured calculated by the method, the heating section and the temperature detection section are arranged side by side in a direction perpendicular to the flow direction of the fluid to be measured, and the characteristic value The acquisition unit acquires the characteristic value based on a ratio of temperatures of the fluid to be measured detected by the temperature detection unit before and after changing the temperature of the heating unit.

By using the characteristic value obtained from the ratio of the temperature of the fluid to be measured detected by the temperature detection unit before and after changing the temperature of the heating part, it is possible to calculate the thermal diffusivity that changes depending on the thermal conductivity, specific heat, and viscosity of the fluid to be measured. Corrections can be made accordingly. Therefore, it is possible to improve the accuracy of flow rate measurement for fluids to be measured having different thermal diffusivities.

Further, in the present invention, the characteristic value acquisition section obtains the characteristic value based on the difference and ratio of the temperature of the fluid to be measured detected by the temperature detection section before and after changing the temperature of the heating section. You may also obtain it.

Here, among the fluids to be measured that have different thermal diffusivities, there are fluids whose physical properties can be accurately reflected by the difference in temperature of the fluid to be measured detected by the temperature detection section before and after changing the temperature of the heating section. There may be a fluid whose physical properties can be accurately reflected by the ratio of the temperature of the fluid to be measured detected by the temperature detection section before and after changing the temperature of the heating section. Therefore, in the present invention, the characteristic value acquisition section acquires the characteristic value based on the difference and ratio of the temperature of the fluid to be measured detected by the temperature detection section before and after changing the temperature of the heating section. By doing so, it is possible to more accurately obtain characteristic values that reflect the physical properties of the fluids to be measured having different thermal diffusivities.

In addition, the characteristic value is a value obtained by multiplying the difference and/or ratio of the temperature of the fluid to be measured detected by the temperature detection unit before and after changing the temperature of the heating unit by a predetermined coefficient. Alternatively, the flow rate of the fluid to be measured may be corrected by multiplying the detection signal output from the flow rate detection section by a characteristic value. Specifically, such a value can be used as a characteristic value.

In addition, one end communicates with a first inlet opened into the main flow path, and the other end communicates with a first outflow port opened into the main flow path, so that the flow is separated from the main flow path, and the characteristic value acquisition unit It is also possible to further include a sub-flow path section having a characteristic value detection flow path in which the temperature detection section is arranged, and the flow rate detection section may be arranged at a different position from the characteristic value detection flow path. By providing the sub-flow path section, it is possible to provide a device that can measure the flow rate regardless of the size and flow rate of the main flow path. Further, it is possible to suppress dust from entering the temperature detection section of the flow rate detection section and the characteristic value acquisition section.

Further, the temperature detection section and the flow rate detection section of the characteristic value acquisition section may be provided in a flow rate detection member that is removably attached to a member that constitutes the main flow channel or the sub flow channel section. In this way, it is possible to provide components that can be attached to the main flow passage section 2 having various flow rates and shapes, and it is possible to reduce costs.

The auxiliary flow path portion communicates with the flow rate detection flow path in which the flow rate detection portion is disposed, and a first inlet port having one end opened into the main flow path, and a first inflow port having the other end opened into the main flow path. A first auxiliary flow path section that is separated from the auxiliary flow path section by communicating with the outflow port, and a second inflow port that has one end opened to the first sub flow path section, and the other end that is connected to the first sub flow path section. It has a second sub-flow path separated from the first sub-flow path by communicating with a second outlet opened in the flow path, and both the flow rate detection flow path and the characteristic value detection flow path have one end. The flow is further divided from the second sub-flow path by communicating with the third inlet opening in the second sub-flow path and having the other end communicating with the third outflow opening in the second sub-flow path. It may also be formed by By employing the three-stage flow dividing structure in this manner, it is possible to further reduce the amount of dust entering the temperature detection section of the flow rate detection section and the characteristic value acquisition section.

Further, the sub-channel section further includes a flow rate detection channel in which a flow rate detection section is disposed, and one end of the flow rate detection channel communicates with the first inlet, and the other end communicates with the first flow port. The fluid to be measured, which is in communication with the outlet and flows in from the first inlet, may be divided into the characteristic value detection channel and the flow rate detection channel. As a specific flow dividing structure, such a configuration can also be adopted.

Further, the sub flow path section further includes a flow rate detection flow path in which a flow rate detection section is arranged, and the characteristic value detection flow path is provided within the flow rate detection flow path. A part of the flowing fluid to be measured may be caused to flow into the characteristic value detection channel. As a specific flow dividing structure, such a configuration can also be adopted.

Further, the sub flow path section further includes a flow rate detection flow path in which a flow rate detection section is disposed, and the flow rate detection flow path communicates with a fourth inlet having one end opened into the main flow path, and The other end may communicate with a fourth outlet opening into the main flow path. As a specific flow dividing structure, such a configuration can also be adopted.

Further, the flow rate detection section may be arranged in the main flow path. In this way, the flow rate detection section may be configured to measure the fluid in the main channel.

Further, the heating section may be arranged such that the longitudinal direction of the heating section is along the flow direction of the fluid to be measured. In this way, the heating section can heat the fluid to be measured over a wide range in the flow direction of the fluid to be measured.

Further, the temperature detection section may be arranged such that the longitudinal direction of the temperature detection section is along the flow direction of the fluid to be measured. In this way, the temperature detection section can detect the temperature over a wide range in the flow direction of the fluid to be measured.

Further, the sub-channel section further includes a flow rate detection channel in which a flow rate detection section is disposed, and the flow rate detection channel and the characteristic value detection channel are arranged in the sub-channel section or branched from the sub-channel section. The temperature of the flow rate detection unit and the characteristic value acquisition unit is The detection units may be provided on one side and the opposite side of the circuit board, respectively. As a specific flow dividing structure, such a configuration can also be adopted.

Note that the contents described in the means for solving the problems can be combined as much as possible without departing from the problems and technical idea of the present invention. Moreover, the contents of the flow rate measuring device shown in the means for solving the problems can be provided as a method or a program to be executed by a processor, a microcontroller, or the like.

The accuracy of flow rate measurement can be improved for fluids to be measured that have different thermal diffusivities.

It is a perspective view showing the device configuration of a flow rate measuring device. FIG. 3 is a longitudinal cross-sectional view of the flow rate measuring device. FIG. 3 is a cross-sectional view of the flow rate measuring device. FIG. 2 is a perspective view showing an example of a sensor element used in a flow rate detection section and a physical property value acquisition section. FIG. 3 is a cross-sectional view for explaining the mechanism of a sensor element. FIG. 2 is a top view showing a schematic configuration of a flow rate detection section. FIG. 3 is a top view showing a schematic configuration of a physical property value acquisition section. FIG. 2 is a block diagram showing the functional configuration of the flow rate measuring device. FIG. 2 is a processing flow diagram showing an example of flow rate measurement processing. FIG. 3 is a processing flow diagram showing an example of characteristic value acquisition processing. It is a graph showing sensor sensitivity ratio on the vertical axis and thermal conductivity on the horizontal axis. It is a graph showing sensor sensitivity ratio on the vertical axis and ΔT on the horizontal axis. It is a figure showing a flow rate measuring device. FIG. 3 is a perspective view showing a sub-channel section. FIG. 2 is a diagram showing a schematic configuration of a physical property value detection section and a flow rate detection section. FIG. 2 is a schematic diagram for explaining the flow rate of a fluid to be measured that is divided into a physical property value detection flow path and a flow rate detection flow path. FIG. 7 is a top view showing a modification of the physical property value detection channel and the flow rate detection channel formed on the upper surface of the sub-channel section. It is a top view which shows the schematic structure of the modification of a physical property value detection part. It is a perspective view showing a flow rate measuring device. It is a figure showing other examples of a flow rate measuring device. It is a figure showing other examples of a flow rate measuring device. It is a figure which shows an example of the multistage separation type|mold based on another modification. It is a sectional view for explaining another modification.

[Application example]
Application examples of the present invention will be described below with reference to the drawings. The present invention is applied to a flow rate measuring device 1 as shown in the block diagram of FIG. In FIG. 8, the flow rate measuring device 1 includes a flow rate detection section 11, a physical property value detection section 12, and a control section 13. The flow rate detection section 11 and the physical property value detection section 12 are configured by a so-called thermal flow sensor 100 including a heating section formed by a microheater 101 and a temperature detection section formed by a thermopile 102, as shown in FIG. be done. The flow rate detection unit 11 includes a first temperature detection unit 111 within the flow rate detection unit and a second temperature detection unit 112 within the flow rate detection unit. The physical property value detection section 12 includes a first temperature detection section 121 within the physical property value detection section, a second temperature detection section 122 within the physical property value detection section, and a heating section 123 within the physical property value detection section.

The flow rate detection unit 11 outputs a value indicating the flow rate to the control unit 13. The physical property value detection section 12 outputs the temperature detection signals output from the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section to the flow rate calculation section 133 . More specifically, the temperature of the heating section 123 in the physical property value detecting section is changed in two stages by the control by the control section 13, and the first temperature detecting section 121 in the physical property value detecting section and the second temperature detecting section 122 in the physical property value detecting section, Output values before and after the temperature change of the heating section 123 in the physical property value detection section are determined and outputted to the control section 13 .

Further, the control unit 13 includes a correction processing unit 131, a characteristic value calculation unit 132, and a flow rate calculation unit 133. The flow rate calculation unit 133 calculates the flow rate of the fluid to be measured based on the detected value of the flow rate detection unit 11. The characteristic value calculation unit 132 calculates characteristic values based on the detection values of the physical property value detection unit 12. Specifically, the characteristic value calculation section 132 changes the temperature of the micro-heater 101, which is the heating section 123 in the physical property value detection section of the physical property value detection section 12, as described above, and changes the temperature of the first heating section in the physical property value detection section before and after the change. A characteristic value is calculated by multiplying the ratio of the temperature of the fluid to be measured detected by the temperature detecting section 121 and the temperature of the fluid to be measured detected by the thermopile 102 as the second temperature detecting section 122 in the physical property value detecting section. The correction processing unit 131 corrects the flow rate calculated by the flow rate calculation unit 133 using the characteristic value. As a result, it is not possible to simply obtain the characteristic values of the fluid to be measured based on the difference in temperature of the fluid to be measured detected by the thermopile before and after changing the temperature of the microheater in two stages. Even if it is difficult to identify the physical properties of fluids, it is possible to sufficiently improve the accuracy of flow rate measurement for fluids to be measured that have different thermal diffusivities.

〔Example〕
DESCRIPTION OF THE PREFERRED EMBODIMENTS A flow rate measuring device according to an embodiment of the present invention will be described below with reference to the drawings. Note that the embodiment shown below is an example of a flow rate measuring device, and the flow rate measuring device according to the present invention is not limited to the following configuration.

<Device configuration>
FIG. 1 is a perspective view showing the configuration of a flow rate measuring device according to this embodiment. FIG. 2 is a longitudinal sectional view of the flow rate measuring device. FIG. 3 is a cross-sectional view of the flow rate measuring device. A flow rate measuring device is incorporated into, for example, a gas meter, a combustion device, an internal combustion engine of an automobile, or a fuel cell, and measures the amount of gas passing through a flow path. Note that the broken line arrow in FIG. 1 indicates the direction in which the fluid flows. As shown in FIGS. 1 to 3, in this embodiment, the flow rate measuring device 1 is provided inside the main flow path section 2. As shown in FIGS. The flow rate measurement device 1 also includes a flow rate detection section 11, a physical property value detection section (also referred to as a "temperature detection section") 12, and a control section 13. The flow rate detection section 11 and the physical property value detection section 12 are so-called thermal flow sensors that include a heating section formed by a microheater and a temperature detection section formed by a thermopile.

FIG. 4 is a perspective view showing an example of a sensor element used in the flow rate detection section and the physical property value acquisition section. Moreover, FIG. 5 is a sectional view for explaining the mechanism of the sensor element. The sensor element 100 includes a microheater (heating section) 101 and thermopiles (temperature detection sections) 102 provided on both sides of the microheater 101. Insulating thin films are formed above and below these, and are provided on a silicon base. Furthermore, a cavity is provided in the silicon base below the microheater 101 and the thermopile 102. Microheater 101 is a resistor made of polysilicon, for example. FIG. 5 schematically shows the temperature distribution when the micro-heater 101 generates heat using a broken-line ellipse. Note that the thicker the broken line, the higher the temperature. When there is no air flow, the temperature distribution on both sides of the microheater 101 is approximately equal, as shown in the upper part (1) of FIG. On the other hand, if air flows in the direction indicated by the dashed arrow in the lower row (2) of FIG. 5, for example, the temperature will be higher on the leeward side of the micro heater 101 than on the windward side because the surrounding air moves. . The sensor element utilizes this uneven distribution of heater heat to output a value indicating the flow rate.

The control unit 13 in FIG. 1 is formed by a calculation device such as a microcontroller, and calculates the flow rate based on the output of the flow rate detection unit 11 and calculates a predetermined characteristic value based on the output of the physical property value detection unit 12. Calculate or correct flow rate using characteristic values.

<Flow rate detection section and physical property value acquisition section>

6 is a top view showing a schematic configuration of the flow rate detection section 11 shown in FIG. 1, and FIG. 7 is a top view showing a schematic structure of the physical property value detection section 12 shown in FIG. 1.

As shown in FIG. 6, the flow rate detection unit 11 includes a first thermopile (first temperature detection unit in the flow rate detection unit) 111 and a second thermopile (second temperature detection unit in the flow rate detection unit) 112 that detect the temperature of the fluid to be measured. and a microheater 113 that heats the fluid to be measured. The micro-heater 113, the first temperature detection section 111 in the flow rate detection section, and the second temperature detection section 112 in the flow rate detection section are arranged side by side in the flow rate detection section 11 along the flow direction P of the fluid to be measured. . Furthermore, the shapes of the micro-heater 113, the first temperature detection section 111 in the flow rate detection section, and the second temperature detection section 112 in the flow rate detection section are each approximately rectangular in plan view, and the longitudinal direction of each is in the flow direction of the fluid to be measured. Orthogonal to P.

The first temperature detection section 111 within the flow rate detection section and the second temperature detection section 112 within the flow rate detection section are arranged such that the first temperature detection section 111 within the flow rate detection section is disposed upstream of the micro heater 113, and the second temperature detection section within the flow rate detection section is arranged downstream of the micro heater 113. A detection unit 112 is arranged to detect temperatures at symmetrical positions with the microheater 113 in between.

In the flow rate measurement device 1, sensors having substantially the same structure are used in the physical property value detection unit 12 and the flow rate detection unit 11, and are arranged at different angles of 90 degrees with respect to the flow direction of the fluid to be measured. . This allows sensors with the same structure to function as the physical property value detection section 12 or the flow rate detection section 11, so that the manufacturing cost of the flow rate measurement device 1 can be reduced.

On the other hand, as shown in FIG. 7, the physical property value detection unit 12 includes a first thermopile (first temperature detection unit in the physical property value detection unit) 121 and a second thermopile (second temperature detection unit in the physical property value detection unit) that detect the temperature of the fluid to be measured. The micro-heater (heating section within the physical property value detection section) 123 heats the fluid to be measured. The heating unit 123 in the physical property value detection unit, the first temperature detection unit 121 in the physical property value detection unit, and the second temperature detection unit 122 in the physical property value detection unit are perpendicular to the flow direction Q of the fluid to be measured in the physical property value detection unit 12. They are arranged in the same direction. In addition, the shapes of the heating section 123 in the physical property value detection section, the first temperature detection section 121 in the physical property value detection section, and the second temperature detection section 122 in the physical property value detection section are each approximately rectangular in plan view, and the longitudinal direction of each is approximately rectangular in plan view. It is along the flow direction Q of the fluid to be measured. Further, the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section are arranged symmetrically with the heating section 123 in the physical property value detection section sandwiched therebetween. Detect the temperature at symmetrical positions on both sides of the

Here, since the temperature distribution is biased toward the downstream side due to the flow of the fluid to be measured, the change in the temperature distribution in the direction perpendicular to the flow direction is smaller than the change in the temperature distribution in the flow direction of the fluid to be measured. Therefore, the first temperature detection section 121 in the physical property value detection section, the heating section 123 in the physical property value detection section, and the second temperature detection section 122 in the physical property value detection section are arranged in this order in a direction perpendicular to the flow direction of the fluid to be measured. By arranging them side by side, it is possible to reduce changes in the output characteristics of the first temperature detection section 121 within the physical property value detection section and the second temperature detection section 122 within the physical property value detection section due to changes in temperature distribution. Therefore, the influence of changes in temperature distribution due to the flow of the fluid to be measured can be reduced, and the detection accuracy by the physical property value detection section 12 can be improved.

In addition, since the longitudinal direction of the heating section 123 in the physical property value detection section is arranged along the flow direction of the fluid to be measured, the heating section 123 in the physical property detection section can cover a wide range of the fluid to be measured in the flow direction of the fluid to be measured. It becomes possible to heat the Therefore, even if the temperature distribution is biased toward the downstream side due to the flow of the fluid to be measured, changes in the output characteristics of the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section are prevented. can be reduced. Therefore, it is possible to reduce the influence of changes in temperature distribution due to the flow of the fluid to be measured, reduce the influence of changes in temperature distribution due to the flow of the fluid to be measured, and improve detection accuracy by the physical property value detection unit 12. .

Furthermore, since the longitudinal direction of the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section is arranged along the flow direction of the fluid to be measured, the first temperature detection section in the physical property value detection section The section 121 and the second temperature detecting section 122 in the physical property value detecting section can detect temperature over a wide range in the flow direction of the fluid to be measured. Therefore, even if the temperature distribution is biased toward the downstream side due to the flow of the fluid to be measured, changes in the output characteristics of the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section are prevented. can be reduced. Therefore, the influence of changes in temperature distribution due to the flow of the fluid to be measured can be reduced, and the detection accuracy by the physical property value detection section 12 can be improved.

<Functional configuration>
FIG. 8 is a block diagram showing the functional configuration of the flow rate measuring device. The flow rate measurement device 1 includes a flow rate detection section 11, a physical property value detection section 12, and a control section 13. The flow rate detection unit 11 includes a first temperature detection unit 111 within the flow rate detection unit and a second temperature detection unit 112 within the flow rate detection unit. The physical property value detection section 12 includes a first temperature detection section 121 within the physical property value detection section, a second temperature detection section 122 within the physical property value detection section, and a heating section 123 within the physical property value detection section.

The flow rate detection unit 11 detects a value indicating the flow rate of the fluid to be measured based on the temperature detection signals output from the first temperature detection unit 111 in the flow rate detection unit and the second temperature detection unit 112 in the flow rate detection unit. Specifically, the flow rate detection unit 11 calculates the difference between the temperature detection signal output from the first temperature detection unit 111 within the flow rate detection unit and the temperature detection signal output from the second temperature detection unit 112 within the flow rate detection unit. , a value indicating the flow rate of the fluid to be measured is determined based on the difference. Then, the flow rate detection section 11 outputs a value indicating the flow rate to the control section 13.

The physical property value detection section 12 outputs the temperature detection signals output from the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section to the flow rate calculation section 133 . Specifically, the physical property value detection unit 12 calculates the average value of the temperature detection signals output from the first temperature detection unit 121 in the physical property value detection unit and the second temperature detection unit 122 in the physical property value detection unit. Further, the heating section 123 within the physical property value detection section changes the temperature according to control by the control section 13, for example. Thereby, the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section can obtain the output values before and after the temperature change of the heating section 123 in the physical property value detection section. The physical property value detection section 12 outputs the acquired output value to the control section 13.

Further, the control unit 13 includes a correction processing unit 131, a characteristic value calculation unit 132, and a flow rate calculation unit 133. The flow rate calculation unit 133 calculates the flow rate of the fluid to be measured based on the detected value of the flow rate detection unit 11. The characteristic value calculation unit 132 calculates characteristic values based on the detection values of the physical property value detection unit 12. Specifically, the characteristic value calculation unit 132 changes the temperature of the microheater of the physical property value detection unit 12, and calculates the characteristic value by multiplying the ratio of the temperature of the fluid to be measured detected by the thermopile before and after the change by a predetermined coefficient. Calculate. The correction processing unit 131 corrects the flow rate calculated by the flow rate calculation unit 133 using the characteristic value. Note that the physical property value detection section 12 and the characteristic value calculation section 132 are also collectively referred to as a characteristic value acquisition section.

<Flow rate measurement process>
FIG. 9 is a processing flow diagram showing an example of flow rate measurement processing. As shown in FIG. 9, the flow rate detection unit 11 outputs temperature detection signals from the first temperature detection unit within the flow rate detection unit and the second temperature detection unit within the flow rate detection unit 112, and the flow rate calculation unit 133 outputs two temperature detection signals. The flow rate of the fluid to be measured is calculated based on (FIG. 9: S1).

Specifically, the flow rate detection unit 11 outputs a temperature detection signal outputted from the first temperature detection unit 111 in the flow rate detection unit and a temperature detection signal outputted from the second temperature detection unit 112 in the flow rate detection unit. Further, the flow rate calculation unit 133 calculates the difference between the two temperature detection signals, and calculates a value indicating the flow rate of the fluid to be measured based on the difference.

Note that a known method can be used to calculate the flow rate of the fluid to be measured based on the temperature detection signals output from the first temperature detection section 111 within the flow rate detection section and the second temperature detection section 112 within the flow rate detection section. . The flow rate detection unit 11 outputs the calculated flow rate of the fluid to be measured to the control unit 13.

Further, the physical property value detection unit 12 executes characteristic value acquisition processing (S2). Details of the characteristic value acquisition process will be explained using FIG. 10.

FIG. 10 is a processing flow diagram showing an example of characteristic value acquisition processing. The characteristic value calculation unit 132 of the control unit 13 causes the physical property value detection unit internal heating unit 123 of the physical property value detection unit 12 to heat at the first temperature (FIG. 10: S11). After that, the first temperature detection section 12 in the physical property value detection section of the physical property value detection section 12
1 and the second temperature detection section 122 in the physical property value detection section detects the first temperature (S12). This step may be performed based on control by the control unit 13, for example. The speed of heat transmitted through the fluid to be measured is determined by physical property values such as thermal conductivity, thermal diffusivity, and specific heat. Furthermore, the thermal conductivity can be determined by detecting the temperature difference between the heating section 123 in the physical property value detection section, the first temperature detection section 121 in the physical property value detection section, and the second temperature detection section 122 in the physical property value detection section. . For example, the larger the temperature difference between the physical property value detection section internal heating section 123 and the physical property value detection section first temperature detection section 121 and physical property value detection section second temperature detection section 122, the smaller the thermal conductivity becomes. Utilizing such properties, in this step, the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section arranged in the direction perpendicular to the flow direction of the fluid to be measured perform measurements. Detects the temperature of the target fluid.

Next, the characteristic value calculation unit 132 of the control unit 13 causes the physical property value detection unit internal heating unit 123 of the physical property value detection unit 12 to heat at a second temperature (S13). Thereafter, the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section of the physical property value detection section 12 detect the second temperature (S14). This step may also be performed based on control by the control unit 13, for example. In this way, values indicating the temperatures detected by the first temperature detection section 121 in the physical property value detection section and the second temperature detection section 122 in the physical property value detection section before and after the temperature change in the heating section 123 in the physical property value detection section are obtained. Ru.

Further, the characteristic value calculation unit 132 calculates a characteristic value using the detected temperature (S15). In this step, the sensor sensitivity ratio is determined. The sensor sensitivity ratio is the ratio of the sensor output value when a predetermined gas is flown to the sensor output value when a reference gas is flown, and is a characteristic value representing the thermal diffusivity. The sensor sensitivity ratio α is determined by the following equation (1).
α = β × rT ... (1)
β is a predetermined coefficient. Further, rT is a ratio of detection values output by the first temperature detection section 121 within the physical property value detection section and the second temperature detection section 122 within the physical property value detection section before and after the temperature change of the heating section 123 within the physical property value detection section.

Thereafter, returning to the process in FIG. 9, the control unit 13 uses the characteristic value to correct the flow rate of the fluid to be measured calculated by the flow rate calculation unit (FIG. 9: S3). Specifically, the control unit 13 calculates the corrected flow rate using equation (2) below.
Output after correction = Output of flow rate calculation section × α ... (2)

In this embodiment, by using the ratio (rT) of the temperature detected by the thermopile before and after changing the temperature of the microheater, the thermal diffusivity of the fluid to be measured can be detected in more detail. Become. Here, the flow rate output by the thermal flow sensor has a correlation with the thermal diffusivity. Therefore, according to the flow rate correction process according to this embodiment, it is possible to appropriately correct all gases. That is, it is possible to improve the accuracy of flow rate measurement for fluids to be measured that have different thermal diffusivities.

FIG. 11 is a graph showing the sensor sensitivity ratio on the vertical axis and the thermal conductivity on the horizontal axis. Here, as shown in Figure 11, when there are multiple gas groups with different physical property values other than thermal conductivity, such as mixed gases with different compositions, it is not possible to just find a certain thermal conductivity as a physical property value. It is unclear which sensor sensitivity ratio should be used for correction. In other words, in the method of making corrections using one set of the heating temperature of the microheater and the detection temperature of the thermopile, corrections were made based on two or more reference gases belonging to a predetermined gas group. It was not possible to make appropriate corrections. In addition, the difference ΔT between the detected values output by the first temperature detecting section 121 and the second temperature detecting section 122 before and after the temperature change of the heating section 123 in the physical property detecting section is sufficiently accurate. It is possible to calculate appropriate characteristic values even for a fluid to be measured for which it has been difficult to calculate good characteristic values.

FIG. 12(a) is a graph showing the sensor sensitivity ratio on the vertical axis and ΔT on the horizontal axis. Even for the gas shown in FIG. 11 in which the sensor sensitivity ratio and the thermal conductivity are not approximated in a straight line, the sensor sensitivity ratio and ΔT are approximated in a straight line. Therefore, in this embodiment, correction can be performed even for a gas group whose thermal diffusivity is unknown. FIG. 12(b) shows the average value of the outputs of the first temperature detecting section 121 in the physical property detecting section and the second temperature detecting section 122 in the physical property detecting section before and after the temperature change in the heating section 123 in the physical property detecting section, and ΔT and rT. FIG.

In this embodiment, the characteristic value was calculated using the ratio (rT) of the temperatures detected by the thermopile before and after changing the temperature of the microheater. In addition, in this embodiment, the characteristic value may be calculated using the difference (ΔT) between the temperatures detected by the thermopile before and after changing the temperature of the microheater. The sensor sensitivity ratio α in that case is determined by the following equation (3).
α = γ × rT + ε × ΔT ... (3)
Here, γ and ε are predetermined coefficients.
As a result, the ratio of the temperature detected by the thermopile before and after changing the temperature of the micro-heater (rT), which is correlated with the thermal diffusivity, and the temperature detected by the thermopile before and after changing the temperature of the micro-heater are determined. The characteristic value can be calculated using both of the differences (ΔT), and it becomes possible to calculate the characteristic value with higher accuracy. In addition, in this embodiment, if the correlation between the thermal diffusivity of the fluid to be measured and the difference in temperature (ΔT) detected by the thermopile before and after changing the temperature of the microheater is very high, the sensor sensitivity The ratio α may be defined by an equation containing only ΔT (a value obtained by multiplying ΔT by a predetermined coefficient).

[Modified example]
In the embodiment described above, the flow sensor of the flow rate measuring device 1 has a configuration in which the fluid in the main flow path section 2 is measured, but the present invention is not limited to such an example. For example, the flow sensor of the flow rate measurement device 1 may measure fluid in a sub-flow path branched from the main flow path portion 2 .

FIG. 13(a) is an exploded perspective view showing the flow rate measuring device 1 according to this embodiment, and FIG. 13(b) is a perspective view showing the flow rate measuring device 1 shown in FIG. 13(a). As shown in FIGS. 13(a) and 13(b), the flow rate measuring device 1 according to the modification includes a main flow path section 2, a sub flow path section 3, a seal 4, a circuit board 5, and a cover 6. ing.

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

In this embodiment, the axial length of the main flow path section 2 is approximately 50 mm, the diameter of the inner peripheral surface (inner diameter of the main flow path section 2) is approximately 20 mm, and the outer diameter of the main flow path section 2 is approximately 50 mm. It is approximately 24 mm.

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

The inflow channel 34 is a channel for allowing the fluid to be measured flowing through the main channel portion 2 to flow in and branching into the physical property value detection channel 32 and the flow rate detection channel 33. The inflow channel 34 is formed in a direction perpendicular to the main channel section 2, penetrating the sub channel section 3, and has one end communicating with the inflow port 34A, and the other end communicating with the upper surface of the main channel section 2. It is open and communicates with the physical property value detection channel 32 and the flow rate detection channel 33. Thereby, a part of the fluid to be measured flowing through the main flow path section 2 can be divided into the physical property value detection flow path 32 and the flow rate detection flow path 33 via the inflow flow path 34.

The physical property value detection flow path 32 is a flow path formed on the upper surface of the sub flow path section 3, extending in a direction parallel to the main flow path section 2, and having a substantially U-shaped vertical section. In the physical property value detection flow path 32, a physical property value detection unit 12 for detecting the physical property value of the fluid to be measured is arranged in a portion extending in the longitudinal direction (in a direction parallel to the main flow path portion 2). 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 33 is a flow path formed on the upper surface of the sub flow path section 3, extending in a direction parallel to the main flow path section 2, and having a substantially U-shaped vertical cross section. The flow rate detection flow path 33 is a flow rate detection flow path in which a flow rate detection unit 11 for detecting the flow rate of the fluid to be measured is arranged in a portion extending in the longitudinal direction (in a direction parallel to the main flow path portion 2). It has 33. One end of the flow rate detection channel 33 communicates with the inlet 34A via the inflow channel 34, and the other end communicates with the outlet 35A via the outflow channel 35.

In addition, in the drawing, for convenience of explanation, the physical property value detecting section 12 and the flow rate detecting section 11 are shown in a separated state from the circuit board 5, but the physical property value detecting section 12 and the flow rate detecting section 11 are It is disposed in the physical property value detection channel 32 or the flow rate detection channel 33 while being mounted on the substrate 5.

The outflow channel 35 is a channel for causing the fluid to be measured that has passed through the physical property value detection channel 32 and the flow rate detection channel 33 to flow out into the main channel section 2 . The outflow channel 35 is formed in a direction perpendicular to the main channel section 2, penetrating the sub channel section 3, one end communicating with the outflow port 35A, and the other end communicating with the upper surface of the main channel section 2. It is open and communicates with the physical property value detection channel 32 and the flow rate detection channel 33. Thereby, the fluid to be measured that has passed through the physical property value detection channel 32 and the flow rate detection channel 33 can flow out into the main channel section 2 via the outflow channel 35.

In this way, by dividing the fluid to be measured that flows in from the same inlet 34A into the physical property value detection channel 32 and the flow rate detection channel 33, the physical property value detection section 12 and the flow rate detection section 11 can detect the temperature. , the physical property value or the flow rate can be detected based on the fluids to be measured that have the same conditions such as concentration. Therefore, the measurement accuracy of the flow rate measuring device 1 can be improved.

In the flow measuring device 1, the circuit board 5 is placed after the seal 4 is fitted into the sub-flow path section 3, and the circuit board 5 is further fixed to the sub-flow path section 3 by the cover 6, so that the sub-flow Airtightness inside the road section 3 is ensured.

FIG. 14 is a perspective view showing the sub-channel section 3 shown in FIG. 13(a). As shown in FIG. 14, the substantially U-shaped end of the physical property value detection channel 32 communicates with the inflow channel 34, and the other end communicates with the outflow channel 35. Similarly, the flow rate detection channel 33 has a substantially U-shaped one end communicating with the inflow channel 34 and the other end communicating with the outflow channel 35 .

Further, both ends of the physical property value detection flow path 32 and the flow rate detection flow path 33 communicate with each other, and the physical property value detection flow path 32 and the flow rate detection flow path 33 are connected to the upper surface of the sub flow path section 3. A rectangular flow path is formed in this section.

In the flow rate measuring device 1, the physical property value detection channel 32 and the flow rate detection channel 33 both have a square shape when viewed from a direction perpendicular to the top surface of the sub-channel section 3, and the inflow channel 34 and the outflow channel 35 at symmetrical positions with respect to the straight line connecting them.

In this embodiment, the length of one side of the physical property value detection flow path 32 and the flow rate detection flow path 33 is approximately 4 mm.

Furthermore, in this embodiment, the physical property value detection channel 32 and the flow rate detection channel 33 have a square shape, but the present invention is not limited to this. The shape of the physical property value detection flow path 32 and the flow rate detection flow path 33 may be such that the physical property value detection section 12 or the flow rate detection section 11 can be arranged, and the shape of the physical property value detection section 12 or the flow rate detection section 11 to be arranged is sufficient. Determined according to the shape.

Therefore, for example, when the size of the physical property value detection section 12 is smaller than the width of the physical property value detection channel 32, the width of the physical property value detection channel 32 is made to match the width of the physical property value detection channel 32. You may let them. In this case, the portion extending in the longitudinal direction of the physical property value detection channel 32 is formed in a linear shape. Note that the same applies to the flow rate detection channel 33.

15(a) is a top view showing a schematic configuration of the physical property value detection unit 12 shown in FIG. 13, and FIG. 15(b) is a top view showing a schematic configuration of the flow rate detection unit 11 shown in FIG. It is. In the flow rate measuring device 1 shown in FIG. 15, the physical property value detection flow path 32 and the flow rate detection flow path 33 have different widths extending in the longitudinal direction, and the physical property value detection flow path 32 and the flow rate detection flow path 33 have different widths extending in the longitudinal direction. The width of the channel in which the physical property value detection section 12 is arranged is narrower than the width of the channel in which the flow rate detection section 11 of the flow rate detection channel 33 is arranged. Thereby, in the flow rate measurement device 1, the flow rate of the fluid to be measured that is divided into the physical property value detection flow path 32 and the flow rate detection flow path 33 is individually controlled.

FIG. 16 is a schematic diagram for explaining the flow rate of the fluid to be measured that is divided into the physical property value detection channel 32 and the flow rate detection channel 33 shown in FIG. As shown in FIG. 16, in the present embodiment, the fluid to be measured with a flow rate P is branched into the flow path 32 for physical property value detection, and the fluid to be measured with a flow rate Q flows into the flow path 33 for flow rate detection. , the widths of the physical property value detection channel 32 and the flow rate detection channel 33 are set.

The values of the flow rate P and the flow rate Q vary depending on the flow rate of the fluid to be measured flowing through the main flow path section 2, but in normal usage, the flow rate P is a value within the detection range of the physical property value detection section 12. The widths of the physical property value detection channel 32 and the flow rate detection channel 33 are set so that the flow rate Q is within the detection range of the flow rate detection section 11.

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

In this way, in the flow rate measuring device 1, it is possible to individually control the flow rate of the fluid to be measured that is divided into the physical property value detection channel 32 and the flow rate detection channel 33 by adjusting the widths of each. be. Therefore, the flow rate of the fluid to be measured flowing through the physical property value detection flow path 32 is controlled according to the detection range of the physical property value detection section 12, and the flow rate of the fluid to be measured flows through the flow rate detection flow path 33 according to the detection range of the flow rate detection section 11. The flow rate of the fluid to be measured can be controlled.

Therefore, the physical property value detection section 12 can detect the physical property value of the fluid to be measured at the optimal flow rate according to the unique detection range, so that the detection accuracy of the physical property value detection section 12 can be improved.

Similarly, the flow rate detection section 11 can detect the flow rate of the fluid to be measured at an optimal flow rate according to the unique detection range, so that the detection accuracy of the flow rate detection section 11 can be improved.

In the above-mentioned modification, as shown in FIG. 16, the physical property value detection channel 32 and the flow rate detection channel 33 are both formed in a substantially U-shape. It is not limited to this. If the physical property value detection channel 32 and the flow rate detection channel 33 are set to a width that allows control of the flow rate of the fluid to be measured that passes through the physical property value detection channel 32 and the flow rate detection channel 33, Its shape is not particularly limited.

17(a) to (d) are top views showing modified examples of the physical property value detection channel 32 and the flow rate detection channel 33 formed on the upper surface of the sub-channel section 3 shown in FIG. be.

As shown in FIG. 17A, for example, the physical property value detection channel 32 may be formed in a straight line, and the flow rate detection channel 33 may be formed in a substantially U-shape.

In addition, as shown in FIGS. 17(b) to 17(d), the physical property value detection flow path 32 is directed from a direction perpendicular to the direction in which the fluid to be measured flows into the flow rate detection flow path 33. The physical property value detection channel 32 may be formed to allow the fluid to be measured to flow therein.

In this case, since the arrangement angles of the physical property value detection section 12 and the flow rate detection section 11 can be matched, the physical property value detection section 12 and the flow rate detection section 11 are mounted on the circuit board 5 during the manufacturing process of the flow rate measuring device 1. The process of doing so can be simplified.

In the above modification, as shown in FIG. 15(a), the physical property value detection section 12 includes a physical property value detection section internal heating section 123 that heats the fluid to be measured, and a physical property value detection section that detects the temperature of the fluid to be measured. The first internal temperature detecting section 121 and the second internal physical property value detecting temperature detecting section 122 are provided, and the first internal physical property value detecting section 121 and the second internal physical property value detecting temperature detecting section 122 are configured to detect internal heating of the physical property value detecting section. Although a configuration in which the parts are arranged symmetrically with the portion 123 in between has been described, the present invention is not limited thereto.

FIG. 18 is a top view showing a schematic configuration of a modified example of the physical property value detection section 12 shown in FIG. 15(a). As shown in FIG. 18, the second temperature detection section 122 in the physical property value detection section is omitted, and the physical property value detection section 12a is composed of the heating section 123 in the physical property value detection section and the first temperature detection section 121 in the physical property value detection section. may be configured.

In this way, the physical property value detecting part 12a may be realized by arranging the heating part in the physical property value detecting part and the first temperature detecting part in the physical property value detecting part in a direction perpendicular to the flow direction of the fluid to be measured. .

[Modification 2]
Another modification of the flow rate measuring device according to the present invention will be described based on FIG. 19. In addition, regarding the member corresponding to the embodiment mentioned above, the corresponding code|symbol is attached|subjected and the description is abbreviate|omitted. In the flow rate measurement device according to this modification, the flow rate detection section is arranged in the main flow path.

FIG. 19(a) is a perspective view showing a flow rate measuring device 1a according to this modification, and FIG. 19(b) is a sectional view showing the flow rate measuring device 1a shown in FIG. 19(a). 19(c) is a top view showing the sub-channel portion 3a shown in FIG. 19(a).

As shown in FIGS. 19(a) to 19(c), in the flow measuring device 1a, an opening 37A is formed between the inlet 34A and the outlet 35A on the inner circumferential surface of the main flow path 2a. ing.

A cellular flow rate detection flow path 37a in which the flow rate detection unit 11 is disposed is formed inside the sub flow path portion 3a, and the flow rate detection flow path 37a communicates with the opening 37A. Therefore, the fluid to be measured flowing through the main flow path 2a flows into the flow rate detection flow path 37a through the opening 37A, and the flow rate is detected by the flow rate detection section 11.

Note that by controlling and adjusting the size of the opening 37A, the flow rate of the fluid to be measured flowing from the main flow path portion 2a into the flow rate detection flow path 37a can be controlled.

The sub-channel portion 3a includes an inflow channel 34, a physical property value detection channel 32, and an outflow channel 35, and the physical property value detection channel 32 extends in the longitudinal direction. The flow path has a physical property value detection flow path 32 in which a physical property value detection unit 12 for detecting the physical property value of the fluid to be measured is arranged.

In this way, in the flow rate measurement device 1a, the physical property value detection section 12 is arranged in the sub-flow path section 3a, and the flow rate detection section 11 is arranged in the main flow path section 2a. Therefore, in the flow rate measuring device 1a, it is possible to control the flow rate according to the detection range of the physical property value detection section 12.

Therefore, according to the present embodiment, it is possible to realize a flow rate measuring device 1a that can reduce changes in output characteristics due to changes in physical properties of the fluid to be measured and can measure the flow rate of the fluid to be measured with high accuracy. .

[Modification 3]
Another modification of the flow rate measuring device according to the present invention will be described based on FIG. 20. In addition, regarding the member corresponding to embodiment, the corresponding code|symbol is attached|subjected and the description is abbreviate|omitted.

The flow rate measuring device according to this modification differs from the above-described flow rate measuring device in that it has two independent sub-channels.

FIG. 20(a) is a perspective view showing the flow rate measuring device 1b according to the present embodiment, and FIG. 20(b) is a top view showing the sub flow path section 3 shown in FIG. 20(a).

As shown in FIGS. 20(a) and 20(b), in the flow measuring device 1b, the sub-channel portion 3b has two sub-channel portions formed inside and on the upper surface thereof.

The first sub-channel section is composed of an inflow channel 34b, a physical property value detection channel 32b, and an outflow channel 35b. A physical property value detection unit 12 for detecting physical property values of the fluid to be measured is arranged in the extending flow path.

The second sub-channel section is composed of an inflow channel 34B, a flow rate detection channel 33B, and an outflow channel 35B. A flow rate detection unit 11 for detecting the flow rate of the fluid to be measured is arranged in the flow path.

In this way, in the flow rate measuring device 1b, the sub-channel section 3b has two independent sub-channels, the physical property value detection section 12 is disposed in the first sub-channel section, and the flow rate detection section 11 is disposed in the first sub-channel section. is arranged in the second sub-channel section. Therefore, according to the flow rate measuring device 1b, it is possible to individually control the flow rates according to the detection ranges of the physical property value detection section 12 and the flow rate detection section 11.

Therefore, according to the present embodiment, it is possible to realize a flow rate measuring device 1b that can reduce changes in output characteristics due to changes in physical properties of the fluid to be measured and can measure the flow rate of the fluid to be measured with high accuracy. .

[Modification 4]
Another modification of the flow rate measuring device according to the present invention will be described based on FIG. 21. In addition, regarding the member corresponding to embodiment, the corresponding code|symbol is attached|subjected and the description is abbreviate|omitted.

The flow rate measurement device according to this modification differs from the above-described flow rate measurement device in that the physical property value detection channel is formed within the flow rate detection channel.

FIG. 21(a) is a perspective view showing the flow rate measuring device 1c according to the present embodiment, and FIG. 21(b) is a perspective view showing the sub-flow path portion 3c shown in FIG. 21(a). FIG. 21(c) is a top view showing the sub-channel portion 3c shown in FIG. 21(a).

As shown in FIGS. 21(a) to 21(c), in the flow rate measuring device 1c, the sub-channel portion 3c includes an inflow channel 34, a physical property value detection channel 32c, and a flow rate detection channel 34. It is composed of a passage 33c and an outflow passage 35.

In the sub flow path section 3c, a physical property value detection flow path 32c is formed within a flow rate detection flow path 33c, and a flow rate detection section 11 is disposed on the upstream side with respect to the flow direction of the fluid to be measured, and A physical property value detection section 12 is arranged on the side.

Here, the physical property value detection channel 32c is separated from the flow rate detection channel 33c by a flow rate control member 40 for controlling the flow rate of the fluid to be measured. is located inside.

The flow rate control member 40 is for controlling the flow rate of the fluid to be measured passing through the physical property value detection channel 32c, and is composed of a first side wall portion 40a and a second side wall portion 40b. The first side wall portion 40a and the second side wall portion 40b are both substantially U-shaped plate members, and are arranged at a predetermined interval with their respective ends facing each other.

Therefore, by controlling the distance between the first side wall portion 40a and the second side wall portion 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 flow path 32c can be adjusted. I can do it.

In this manner, in the flow rate measurement device 1c, the sub-flow path portion 3c includes the flow rate control member 40, and the physical property value detection flow path 32c is provided inside the flow rate control member 40. It becomes possible to provide the physical property value detection channel 32c at an arbitrary position. Moreover, by providing the flow rate control member 40, the flow rate of the fluid to be measured passing through the physical property value detection channel 32c can be easily controlled.

In this way, even if the physical property value detection flow path 32c is formed within the flow rate detection flow path 33c, the flow rate can be determined individually according to the detection range of the physical property value detection section 12 and the flow rate detection section 11. It is possible to control.

Therefore, according to the present embodiment, it is possible to realize a flow rate measuring device 1c that can reduce changes in output characteristics due to changes in physical properties of the fluid to be measured and can measure the flow rate of the fluid to be measured with high accuracy. .

[Modification 5]
FIGS. 22(a) to 22(c) are diagrams showing an example of a multi-stage branch type according to another modification. FIG. 22(c) shows a connection point between the main flow path section 2d and the flow rate measuring device 1d. FIG. 22(b) is an enlarged view of the portion indicated by the dashed rectangle in FIG. 22(c). Further, FIG. 22(a) is a sectional view taken along line AA of the unit 1000 in FIG. 22(c). As shown in an enlarged view in FIG. 22(b), in this modification, a sub-flow path section 3d that is thinner (having a smaller cross-sectional area) than the main flow path section 2d is provided along the flow direction of the main flow path section 2. ing. Further, the sub-channel section 3d branches into a main channel 2e penetrating along the main channel section 2d, and a sub-channel section 3e connected substantially perpendicularly to the sub-channel section 3d. As shown in FIG. 22(a), the sub-flow path section 3e is divided into a sub-flow path section 3f in which the flow rate detection section 11 is provided and a sub-flow path section 3g in which the physical property value detection section 12 is provided. Branch out.

According to the above-described modification having the sub-flow path, the flow rate can be measured using the small-sized flow rate measuring device 1d, regardless of the flow rate of the main flow path portion 2d (that is, the thickness (cross-sectional area) of the main flow path portion 2d). In addition, according to the above-mentioned modification having the sub-flow path, it is possible to suppress the intrusion of dust into the sensor chip and improve measurement accuracy, but as in the modification shown in FIG. If this is adopted, the amount of dust intrusion can be further reduced.

Further, like the unit 1000 shown in FIG. 22, for example, a component having a sub-flow path section 3f in which a flow rate detection section 11 is provided and a sub-flow path section 3g in which a physical property value detection section 12 is provided can be freely attached and detached. It may also be formed as a separate part. In this way, it is possible to provide components that can be attached to the main flow passage section 2 having various flow rates and shapes, and it is possible to reduce costs.

FIG. 23 is a sectional view for explaining another modification. In the example of FIG. 23, a flow rate detection section 11 and a physical property value detection section 12 are arranged on the front and back sides of the circuit board, respectively. A sub-flow path is provided through the circuit board. The embodiment is not limited to providing a tubular sub-flow path, and a branching structure as shown in FIG. 23 may be adopted.

Note that in order to make it possible to compare the constituent features of the present invention and the configurations of the embodiments, the constituent features of the present invention will be described below with reference numerals in the drawings.
<Invention 1>
a flow rate detection unit (11) for detecting the flow rate of the fluid to be measured flowing through the main flow path;
a characteristic value acquisition unit that has a heating unit (123) that heats the fluid to be measured and a temperature detection unit (121, 122) that detects the temperature of the fluid to be measured, and that acquires the characteristic value of the fluid to be measured;
a flow rate correction unit (10) that corrects the flow rate of the fluid to be measured calculated based on the detection signal output from the flow rate detection unit (11) using the characteristic value of the fluid to be measured acquired by the characteristic value acquisition unit; 131) and
Equipped with
The heating unit (123) and the temperature detection unit (121, 122) are arranged side by side in a direction perpendicular to the flow direction of the fluid to be measured,
The characteristic value acquisition unit acquires the characteristic value based on a ratio of temperatures of the fluid to be measured detected by the temperature detection unit (121, 122) before and after changing the temperature of the heating unit (123). A flow rate measuring device (1) characterized by:
<Invention 14>
It has a heating part (113) that heats the fluid to be measured and a temperature detection part (111, 112) that detects the temperature of the fluid to be measured, which are arranged in parallel in the flow direction of the fluid to be measured. a flow rate detection unit (11) for detecting the flow rate of the target fluid;
It has a second heating part (123) that heats the fluid to be measured and a second temperature detection part (121, 123) that detects the temperature of the fluid to be measured, which are arranged side by side in a direction perpendicular to the flow of the fluid to be measured. and a characteristic value acquisition unit for acquiring characteristic values of the fluid to be measured;
A method for measuring the flow rate of the fluid to be measured using a flow rate measuring device (1) comprising:
a flow rate detection step (S1) in which the flow rate detection unit (11) detects the flow rate of the fluid to be measured flowing through the main channel;
a first temperature measurement step (S12) of measuring the temperature of the fluid to be measured by the second temperature detection unit (121, 123);
a temperature changing step (S13) of changing the temperature of the second heating section (123);
After the temperature change step (S13), a second temperature measurement step (S14) in which the second temperature detection section (121, 123) measures the temperature of the fluid to be measured;
A characteristic value that obtains the characteristic value based on the ratio of the temperature of the fluid to be measured measured in the first temperature measurement step (S12) and the temperature of the fluid to be measured measured in the second temperature measurement step. an acquisition step (S15);
a correction step (S3) of correcting the flow rate of the fluid to be measured by multiplying the flow rate of the fluid to be measured detected in the flow rate detection step (S1) by the characteristic value;
A method for measuring a flow rate, comprising:
<Invention 15>
It has a heating part (113) that heats the fluid to be measured and a temperature detection part (111, 112) that detects the temperature of the fluid to be measured, which are arranged in parallel in the flow direction of the fluid to be measured. a flow rate detection unit (11) for detecting the flow rate of the target fluid;
It has a second heating part (123) that heats the fluid to be measured and a second temperature detection part (121, 123) that detects the temperature of the fluid to be measured, which are arranged side by side in a direction perpendicular to the flow of the fluid to be measured. and a characteristic value acquisition unit for acquiring characteristic values of the fluid to be measured;
A flow rate measurement program that causes a flow rate measurement device (1) equipped with a flow rate measurement device (1) to measure the flow rate of the fluid to be measured,
In the information processing device,
a flow rate detection step (S1) in which the flow rate detection unit (11) detects the flow rate of the fluid to be measured flowing through the main channel;
a first temperature measurement step (S12) of measuring the temperature of the fluid to be measured by the second temperature detection unit (121, 123);
a temperature changing step (S13) of changing the temperature of the second heating section (123);
After the temperature change step (S13), a second temperature measurement step (S14) of measuring the temperature of the fluid to be measured by the second temperature detection section (121, 123);
A characteristic value that obtains the characteristic value based on a ratio between the temperature of the fluid to be measured measured in the first temperature measurement step (S12) and the temperature of the fluid to be measured measured in the second temperature measurement step. an acquisition step (S15);
a correction step (S3) of correcting the flow rate of the fluid to be measured by multiplying the flow rate of the fluid to be measured detected in the flow rate detection step (S1) by the characteristic value;
A flow rate measurement program to run.

1 : Flow rate measurement device 2 : Main flow path part 3 : Sub flow path part 5 : Circuit board 11 : Flow rate detection part 111 : First temperature detection part in the flow rate detection part 112 : Second temperature detection part in the flow rate detection part 113 : Micro heater 12 : Physical property value detection section 121 : First temperature detection section in the physical property value detection section 122 : Second temperature detection section in the physical property value detection section 123 : Heating section in the physical property value detection section 13 : Control section 131 : Correction processing section 132 : Characteristic value calculation section 32 : Physical property value detection channel 33 : Flow rate detection channel 34 : Inflow channel 100 : Sensor element 101 : Micro heater 102 : Thermopile 1000 : Unit

Claims (15)

a flow rate detection unit for detecting the flow rate of the fluid to be measured flowing through the main flow path;
a characteristic value acquisition unit that has a heating unit that heats the fluid to be measured and a temperature detection unit that detects the temperature of the fluid to be measured, and obtains a characteristic value of the fluid to be measured;
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 characteristic value of the fluid to be measured acquired by the characteristic value acquisition unit;
Equipped with
The heating section and the temperature detection section are arranged side by side in a direction perpendicular to the flow direction of the fluid to be measured,
The characteristic value acquisition section acquires the characteristic value based on a ratio of temperatures of the fluid to be measured detected by the temperature detection section before and after changing the temperature of the heating section. Device. The characteristic value acquisition unit acquires the characteristic value based on the difference and ratio of the temperature of the fluid to be measured detected by the temperature detection unit before and after changing the temperature of the heating unit. The flow rate measuring device according to claim 1. The characteristic value is a difference and ratio of the temperature of the fluid to be measured detected by the temperature detection unit before and after changing the temperature of the heating unit, or a value obtained by multiplying the temperature ratio by a predetermined coefficient. can be,
3. The flow rate measurement according to claim 1, wherein the flow rate correction section corrects the flow rate of the fluid to be measured by multiplying the detection signal output from the flow rate detection section by the characteristic value. Device. One end communicates with a first inlet opening in the main flow path, and the other end communicates with a first outflow port open in the main flow path, so that the flow is separated from the main flow path, and the characteristic value further comprising a sub-channel section having a characteristic value detection channel in which the temperature detection section of the acquisition section is arranged,
The flow rate measuring device according to any one of claims 1 to 3, wherein the flow rate detection section is arranged at a position different from the characteristic value detection channel. The temperature detection section and the flow rate detection section of the characteristic value acquisition section are provided in a flow rate detection member that is detachably provided to a member constituting the main flow channel or the sub flow channel section. The flow rate measuring device according to claim 4. The sub-channel section includes a flow rate detection channel in which the flow rate detection section is arranged;
A first subflow branched from the subflow path by having one end communicating with a first inflow port opened into the main flow path and the other end communicating with a first outflow port opened into the main flow path. A flow path section;
One end communicates with a second inlet opened in the first sub-channel, and the other end communicates with a second outlet opened in the first sub-channel, thereby forming the first sub-channel. a second sub-channel section separated from the section;
has
Both the flow rate detection channel and the characteristic value detection channel have one end communicating with a third inlet opening in the second sub-channel section, and the other end opening into the second sub-channel section. 6. The flow rate measuring device according to claim 4, wherein the flow rate measuring device is formed by being further divided from the second sub-flow path section by communicating with a third outlet. The sub-channel section further includes a flow rate detection channel in which the flow rate detection section is arranged,
The flow rate detection channel has one end communicating with the first inlet and the other end communicating with the first outlet,
6. The flow rate measuring device according to claim 4, wherein the fluid to be measured that flows in from the first inlet is divided into the characteristic value detection channel and the flow rate detection channel. The sub-channel section further includes a flow rate detection channel in which the flow rate detection section is arranged,
The characteristic value detection channel is provided within the flow rate detection channel,
6. The flow rate measuring device according to claim 4, wherein a part of the fluid to be measured flowing in the flow rate detection channel is caused to flow into the characteristic value detection channel. The sub-channel section further includes a flow rate detection channel in which the flow rate detection section is arranged,
The flow rate detection flow path is characterized in that one end communicates with a fourth inlet opened into the main flow path, and the other end communicates with a fourth outflow port opened into the main flow path. The flow rate measuring device according to claim 4 or 5. The flow rate measuring device according to any one of claims 1 to 5, wherein the flow rate detection section is arranged in the main flow path. 11. The flow rate measuring device according to claim 1, wherein the heating section is arranged such that the longitudinal direction of the heating section is along the flow direction of the fluid to be measured. 12. The flow rate measuring device according to claim 1, wherein the temperature detecting section is arranged such that a longitudinal direction of the temperature detecting section is arranged along a flow direction of the fluid to be measured. The sub-channel section further includes a flow rate detection channel in which the flow rate detection section is arranged,
The flow rate detection flow path and the characteristic value detection flow path are configured such that a circuit board is disposed in the sub-flow path portion or a flow path branched from the sub-flow path portion in parallel to the flow direction of the fluid to be measured. Formed by a sub-flow path portion or by dividing the sub-flow path portion,
6. The flow rate measuring device according to claim 4, wherein the flow rate detection section and the temperature detection section of the characteristic value acquisition section are provided on one surface and the opposite surface of the circuit board, respectively. It has a heating part that heats the fluid to be measured and a temperature detection part to detect the temperature of the fluid to be measured, which are arranged side by side in the flow direction of the fluid to be measured, and for detecting the flow rate of the fluid to be measured flowing through the main channel. a flow rate detection section;
It has a second heating part that heats the fluid to be measured and a second temperature detection part to detect the temperature of the fluid to be measured, which are arranged side by side in a direction perpendicular to the flow of the fluid to be measured, and a characteristic value of the fluid to be measured. a characteristic value acquisition unit for acquiring
A method for measuring the flow rate of the fluid to be measured using a flow rate measuring device comprising:
a flow rate detection step of detecting the flow rate of the fluid to be measured flowing through the main flow path by the flow rate detection unit;
a first temperature measurement step of measuring the temperature of the fluid to be measured by the second temperature detection section;
a temperature changing step of changing the temperature of the second heating section;
a second temperature measurement step of measuring the temperature of the fluid to be measured by the second temperature detection section after the temperature change step;
a characteristic value acquisition step of acquiring the characteristic value based on the ratio of the temperature of the fluid to be measured measured in the first temperature measurement step and the temperature of the fluid to be measured measured in the second temperature measurement step; ,
a correction step of correcting the flow rate of the fluid to be measured by multiplying the flow rate of the fluid to be measured detected in the flow rate detection step by the characteristic value;
A method for measuring a flow rate, comprising: It has a heating part that heats the fluid to be measured and a temperature detection part to detect the temperature of the fluid to be measured, which are arranged side by side in the flow direction of the fluid to be measured, and for detecting the flow rate of the fluid to be measured flowing through the main channel. a flow rate detection section;
It has a second heating part that heats the fluid to be measured and a second temperature detection part to detect the temperature of the fluid to be measured, which are arranged side by side in a direction perpendicular to the flow of the fluid to be measured, and a characteristic value of the fluid to be measured. a characteristic value acquisition unit for acquiring
A flow rate measurement program that causes a flow rate measurement device equipped with a flow rate measurement device to measure the flow rate of the fluid to be measured, the program comprising:
In the information processing device,
a flow rate detection step of detecting the flow rate of the fluid to be measured flowing through the main flow path by the flow rate detection unit;
a first temperature measurement step of measuring the temperature of the fluid to be measured by the second temperature detection section;
a temperature changing step of changing the temperature of the second heating section;
a second temperature measurement step of measuring the temperature of the fluid to be measured by the second temperature detection section after the temperature change step;
a characteristic value acquisition step of acquiring the characteristic value based on the ratio of the temperature of the fluid to be measured measured in the first temperature measurement step and the temperature of the fluid to be measured measured in the second temperature measurement step; ,
a correction step of correcting the flow rate of the fluid to be measured by multiplying the flow rate of the fluid to be measured detected in the flow rate detection step by the characteristic value;
A flow rate measurement program to run.

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