FLOW METER, METHOD FOR FLOW MEASUREMENT AND FLOW MEASUREMENT PROGRAM

Abstract

Flow meter, characterized by: a flow detector designed to detect the flow of a fluid to be measured flowing through a main flow path, a characteristic value preservation section comprising: a heating section designed to heat the fluid to be measured, and a temperature detector designed to detect the temperature of the fluid to be measured and to preserve a characteristic value of the fluid to be measured, as well as a flow correction section designed to correct the flow rate of the fluid to be measured, calculated on the basis of a detection signal output by the flow detector, using the characteristic value of the fluid to be measured obtained by the characteristic value preservation section, wherein the heating section and the temperature detector are arranged next to each other in a direction orthogonal to the flow direction of the fluid to be measured, and wherein the characteristic value is obtained from the ratio of the temperature of the fluid to be measured, as detected by the temperature detector, before and after a change in the temperature of the heating section.

Description

TECHNICAL FIELD

[0001] The present invention relates to a flow meter, a method for flow measurement and a program for flow measurement. BACKGROUND TECHNOLOGY

[0002] Conventionally, flowmeters equipped with a heating section and a temperature detector are proposed, and measure the flow of a fluid to be measured. For example, to reduce changes in the output behavior based on changes in the material properties of the fluid to be measured, a flowmeter equipped with a material property value detector configured to detect a material property value of the fluid to be measured is also proposed (JP 2012-233776 A). Specifically, the thermal conductivity (thermal diffusion constant) is determined by detecting the temperature difference between a micro heater and a thermopile, and a flow rate measured by a sensor is corrected based on the thermal conductivity.

[0003] Furthermore, a flowmeter is proposed in which, with respect to a fluid to be measured with different thermal diffusivities, a micro-heater and a thermopile for material detection are arranged side by side in a direction orthogonal to the flow direction of the fluid to be measured, in order to improve the precision of the flow measurement. These thermopiles are arranged to detect the temperature difference of the fluid to be measured before and after a two-stage change in the temperature of the micro-heater. In this technique, a characteristic value is obtained from the temperature difference of the fluid to be measured before and after a two-stage change in the temperature of the micro-heater, and the obtained characteristic value is used to correct the flow of the fluid to be measured (JP 2017-129470 A). OVERVIEW OF THE INVENTION

[0004] However, as the type of fluid to be measured increases, it becomes difficult to identify the material properties of the fluid to be measured with sufficient precision by simply obtaining the characteristic value of the fluid to be measured from the temperature difference of the fluid to be measured, which is detected by the thermopile before and after the two-stage change in the temperature of the micro-heater. Therefore, it may have been difficult to sufficiently improve the precision of flow measurement with respect to the fluid to be measured with different thermal diffusivities.

[0005] The present invention was made in view of the above-mentioned problem and aims to further improve the precision of flow measurement with respect to the fluid to be measured with different thermal diffusivities.

[0006] The flowmeter of the present invention comprises: a flow detector configured to detect a flow rate of a fluid to be measured flowing through a main flow path; a characteristic value obtaining section having a heating section configured to heat the fluid to be measured and a temperature detector configured to detect the temperature of the fluid to be measured, and configured to obtain a characteristic value of the fluid to be measured; and a flow correction section configured to correct the flow rate of the fluid to be measured, which is calculated on the basis of a detection signal output from the flow detector, using the characteristic value of the fluid to be measured obtained by the characteristic value obtaining section; wherein the heating section and the temperature detector are arranged side by side in a direction orthogonal to the flow direction of the fluid to be measured.and wherein the characteristic value obtaining section obtains the characteristic value from the ratio of the temperature of the fluid to be measured detected by the temperature detector before and after the change in the temperature of the heating section.,

[0007] By using the characteristic value calculated from the ratio of the temperature of the measured fluid detected by the temperature detector before and after the change in the temperature of the heating section, it is possible to make corrections according to the thermal diffusivity, which varies depending on the thermal conductivity, specific heat, and viscosity of the measured fluid. Therefore, the precision of flow measurement can be improved with respect to the measured fluid with different thermal diffusivities.

[0008] In the present invention, the characteristic value obtaining section can also obtain the characteristic value from the difference and the ratio of the temperature of the fluid to be measured detected by the temperature detector before and after the change in the temperature of the heating section.

[0009] Here, among the fluid to be measured with different thermal diffusivities, there may be: a fluid that can highly accurately reflect the material properties through the difference of the temperature of the fluid to be measured detected by the temperature detector before and after the change of the temperature of the heating section, and a fluid that can highly accurately reflect the material properties through the ratio of the temperature of the fluid to be measured detected by the temperature detector before and after the change of the temperature of the heating section.In the present invention, therefore, it is possible for the characteristic value obtaining section to obtain a characteristic value reflecting the material properties of the fluid to be measured having different thermal diffusivity with high precision by obtaining the characteristic value from the difference and the ratio of the temperature of the fluid to be measured detected by the temperature detector before and after the change in the temperature of the heating section.

[0010] Furthermore, 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 detector, before and after the temperature change of the heating section by a predetermined factor. The flow correction section can correct the flow of the fluid to be measured by multiplying the detection signal output by the flow detector by the characteristic value. Specifically, such a value can be used as the characteristic value.

[0011] A secondary flow path section may be further provided, which branches off from the main flow path with one end opening into a first inlet opening opened in the main flow path and the other end opening into a first outlet opening opened in the main flow path, and has a characteristic value detection flow path in which the temperature detector of the characteristic value obtaining section is arranged, wherein the flow detector may be arranged in a position different from the characteristic value detection flow path. By providing the secondary flow path section, a device for measuring the flow rate can be provided regardless of the size and flow rate of the main flow path. Furthermore, the intrusion of dust into the flow detector and the temperature detector of the characteristic value obtaining section can be suppressed.

[0012] The temperature detector of the characteristic value acquisition section and the flow detector may also be provided on a flow detection element that is detachable from a member forming the main flow path or the secondary flow path section. In this way, it is possible to provide an element that can be attached to the main flow path section 2 with various flow rates and shapes, thus reducing costs.

[0013] The secondary flow path section further comprises: a flow detection flow path in which the flow detector is arranged, a first secondary flow path section branched off from the secondary flow path section by one end opening into a first inlet opening opened in the main flow path and the other end opening into a first outlet opening opened in the main flow path, and a second secondary flow path section branched off from the first secondary flow path section by one end opening into a second inlet opening opened in the first secondary flow path section and the other end opening into a second outlet opening opened in the first secondary flow path section, wherein both the flow detection flow path and the characteristic value detection flow path can also be formed by further branching off from the second secondary flow path section,One end opens into a third inlet opening located in the second secondary flow path section, and the other end opens into a third outlet opening located in the second secondary flow path section. By adopting such a three-stage branch structure, the amount of dust intrusion into the flow detector and the temperature detector of the characteristic value maintenance section can be further reduced.

[0014] The secondary flow path section further includes a flow detection flow path in which the flow detector is arranged. The flow detection flow path may also be configured such that one end opens into the first inlet port and the other end opens into the first outlet port, and a fluid to be measured flowing in from the first inlet port branches off to the characteristic value detection flow path and the flow detection flow path. Such a configuration may also be used as a specific branch structure.

[0015] The secondary flow path section further includes a flow detection flow path in which the flow detector is arranged. The characteristic detection flow path may also be configured to be provided in the flow detection flow path and allow a portion of the fluid to be measured flowing through the flow detection flow path to flow into the characteristic detection flow path. Such a configuration may also be used as a specific branch structure.

[0016] The secondary flow path section further includes a flow detection flow path in which the flow detector is arranged. The flow detection flow path may also be configured such that one end opens into a fourth inlet opening opened in the primary flow path, and the other end opens into a fourth outlet opening opened in the primary flow path. Such a configuration may also be used as a specific branch structure.

[0017] The flow detector can also be arranged in the main flow path. In this way, the flow detector can also be designed so that it measures the fluid in the main flow path.

[0018] The heating section can also be arranged such that the longitudinal direction of the heating section runs along the flow direction of the fluid to be measured. In this way, the heating section can heat the fluid to be measured to a large extent across the flow direction of the fluid to be measured.

[0019] The temperature detector can also be arranged such that its longitudinal direction runs along the flow direction of the fluid to be measured. In this way, the temperature detector can detect temperature across the flow direction of the fluid to be measured.

[0020] The bypass flow path section further includes a flow detection flow path in which the flow detector is disposed. The flow detection flow path and the characteristic value detection flow path are formed by disposing a circuit board parallel to the flow direction of the fluid to be measured in the bypass flow path section or in a flow path branched from the bypass flow path section, so as to branch off the bypass flow path section or the flow path branched from the bypass flow path section. The flow detector and the temperature detector of the characteristic value acquisition section are provided on one surface and the opposite surface of the circuit board, respectively. Such a configuration can also be applied as a specific branching structure.

[0021] The content provided in the means for solving the problem can be combined as much as possible without deviating from the object and technical spirit of the present invention. The content of the flowmeter presented in the means for solving the problem can also be provided as a method or program for execution by a processor, a microcontroller, etc.

[0022] Depending on the fluid to be measured, which has different thermal diffusivities, the precision of the flow measurement can be improved. BRIEF EXPLANATION OF THE DRAWINGS Fig. 1 is a perspective view showing the mechanical structure of a flowmeter; Fig. 2 is a longitudinal section of the flowmeter; Fig. 3 is a cross-section of the flowmeter; Fig. 4 is a perspective view showing an example of a sensor element used for a flow detector and a material property value maintaining section; Fig. 5 is a cross-sectional view illustrating the mechanism of the sensor element; Fig. 6 is a plan view showing the schematic structure of the flow detector; Fig. 7 is a plan view showing the schematic structure of the material property value maintaining section; Fig. 8 is a block diagram showing a functional structure of the flowmeter; Fig. 9 is a processing flowchart showing an example of flow measurement processing; Fig. 10 is a processing flowchart showing an example of processing for obtaining a characteristic value; Fig. 11 is a graph showing the sensor sensitivity ratio on the ordinate and the thermal conductivity on the abscissa; Fig. 12A and Fig. 12B are graphs plotting the sensor sensitivity ratio on the ordinate and ΔT on the abscissa; Fig. 13A and Fig. 13B are views showing the flowmeter; Fig. 14 is a perspective view showing a bypass flow path portion; Fig. 15A and Fig. 15B are views showing the schematic structure of a material property value detector and the flow detector; Fig. 16 is a schematic view illustrating the flow of a fluid to be measured branching to a flow path for detecting a value of material properties and a flow path for detecting a flow rate; Fig. 17A, Fig. 17B, Fig. 17C and Fig. 17D are plan views showing modified examples of the flow path for detecting a value of the material properties and the flow path for detecting a flow rate formed on the upper side of the sub-flow path portion; Fig. 18 is a plan view showing the schematic structure of a modified example of the material property value detector; Fig. 19A, Fig. 19B and Fig. 19C are perspective views showing the flowmeter; Fig. 20A and Fig. 20B are views showing another example of the flowmeter; Fig. 21A, Fig. 21B and Fig. 21C are views showing another example of the flowmeter; Fig. 22A, Fig. 22B and Fig. 22C are views showing an example of a multi-stage branch type according to another modified example; and Fig. 23 is a cross-sectional view illustrating another modified example. EMBODIMENTS OF THE INVENTION[Application Example]

[0023] An application example of the present invention will be explained below with reference to the drawings. The present invention is applied to a flowmeter 1 as shown in the block diagram of Fig. 8 shown. In Fig. 8, the flowmeter 1 is provided with a flow detector 11, a material property value detector 12, and a controller 13. The flow detector 11 and the material property value detector 12 are connected by a so-called thermal flow sensor 100, including a heating section formed by a micro-heater 101 and a temperature detector formed by a thermopile 102, as shown in Fig. 4. The flow detector 11 is provided with a first temperature detector 111 in the flow detector and a second temperature detector 112 in the flow detector. The material property value detector 12 is provided with a first temperature detector 121 in the material property value detector, a second temperature detector 122 in the material property value detector, and a heating section 123 in the material property value detector.

[0024] The flow rate detector 11 outputs a value indicative of the flow rate to the controller 13. The material property value detector 12 outputs a temperature detection signal output by the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector to a flow rate calculation section 133. In detail, the temperature of the heating section 123 in the material property value detector is changed in two stages under control by the controller 13, and the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector obtain output values ​​before and after the temperature change of the heating section 123 in the material property value detector and output the output values ​​to the controller 13.

[0025] The controller 13 further includes a correction processing section 131, a characteristic value calculation section 132, and a flow calculation section 133. The flow calculation section 133 calculates the flow of the fluid to be measured based on the detection value of the flow detector 11. The characteristic value calculation section 132 calculates a characteristic value based on the detection value of the detector 12 of a value of the material properties.Specifically, the characteristic value calculation section 132 changes the temperature of the micro heater 101, which constitutes the heating section 123 in the material property value detector of the material property value detector 12, as described above, and calculates the characteristic value by multiplying the ratio of the temperature of the fluid to be measured, which is detected by the thermopile 102 as the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector before and after the change, by a predetermined factor. The correction processing section 131 corrects the flow rate calculated by the flow calculation section 133 using the characteristic value.This makes it possible to sufficiently improve the precision of flow measurement with respect to the fluid to be measured with different thermal diffusivity, even though it is difficult to identify the material properties of the fluid to be measured with sufficient precision by only obtaining the characteristic value of the fluid to be measured from the temperature difference of the fluid to be measured detected by the thermopile before and after the two-stage change of the temperature of the micro-heater. [Example]

[0026] The flowmeter according to an embodiment of the present invention will be explained below with reference to the drawings. The embodiment shown below is an example of a flowmeter, and the flowmeter according to the present invention is not limited to the following configurations. <Mechanischer Aufbau>

[0027] Fig. 1 is a perspective view showing the mechanical structure of the flowmeter in this embodiment. Fig. 2 is a longitudinal section of the flowmeter. Fig. Figure 3 is a cross-section of the flowmeter. The flowmeter is installed in, for example, a gas meter, a combustion device, an automobile's internal combustion engine, or a fuel cell, and measures the amount of gas flowing through the flow path. The dashed arrow in Fig. 1 shows an example of the flow direction of the fluid. As in Fig. As shown in Figures 1 to 3, the flowmeter 1 in this embodiment is provided within the main flow path section 2. The flowmeter 1 is further provided with the flow detector 11, the material property value detector 12 (also referred to as a "temperature detector"), and the controller 13. The flow detector 11 and the material property value detector 12 are so-called thermal flow sensors, which include the heating section formed by a micro heater and the temperature detector formed by a thermopile.

[0028] Fig. 4 is a perspective view showing an example of a sensor element used for the flow detector and the material property value obtaining section. Fig. Figure 5 is a cross-sectional view illustrating the mechanism of the sensor element. The sensor element 100 is provided with a micro heater (heating section) 101 and a thermopile (temperature detector) 102 arranged on both sides above the micro heater 101. A thin insulating film is formed on the top and bottom surfaces of the micro heater 101 and is provided on a silicon base. Furthermore, a cavity (hollow space) is provided in the silicon base below the micro heater 101 and the thermopile 102. The micro heater 101 is a resistor body made of, for example, polysilicon. Fig. Figure 5 schematically shows the temperature distribution during heating of the micro heater 101 using a dashed oval line. The thicker the dashed line, the higher the temperature is assumed. In the absence of air flow, the temperature distribution on both sides of the micro heater 101 is almost uniform, as in the upper stage (1) of Fig. 5. On the other hand, for example, if the air flows in the direction indicated by the dashed arrow in the lower stage (2) of Fig. 5, the temperature on the leeward side of the micro heater 101 is higher than on the windward side of the micro heater 101 due to the movement of the ambient air. Using this imbalance in the distribution of the heating heat, the sensor element outputs a value that indicates the flow.

[0029] The control 13 of Fig. 1 is further constituted by a computing unit such as a microcontroller, and calculates the flow rate based on the output of the flow rate detector 11, calculates a predetermined characteristic value based on the output of the material property value detector 12, or corrects the flow rate using the characteristic value. <Durchflussdetektor und Abschnitt zur Erhaltung eines Wertes der Materialeigenschaften>

[0030] Fig. 6 is a plan view showing the schematic structure of the Fig. 1 shown flow detector 11, and Fig. 7 is a plan view showing the schematic structure of the Fig. 1 shows a value of the material properties of the detector 12.

[0031] As in Fig. As shown in Figure 6, the flow detector 11 is provided with a first thermopile (first temperature detector in the flow detector) 111 and a second thermopile (second temperature detector in the flow detector) 112 for detecting the temperature of the fluid to be measured, as well as a micro heater 113 for heating the fluid to be measured. The micro heater 113, the first temperature detector 111 in the flow detector, and the second temperature detector 112 in the flow detector are arranged side by side in the flow detector 11 along the flow direction P of the fluid to be measured. Furthermore, the shapes of the micro heater 113, the first temperature detector 111 in the flow detector, and the second temperature detector 112 in the flow detector are each substantially rectangular in plan view, and their respective longitudinal directions are orthogonal to the flow direction P of the fluid to be measured.

[0032] The first temperature detector 111 in the flow detector and the second temperature detector 112 in the flow detector detect the temperature at symmetrical positions across the micro heater 113, with the first temperature detector 111 in the flow detector being arranged upstream of the micro heater 113 and the second temperature detector 112 in the flow detector being arranged downstream.

[0033] In the flowmeter 1, a substantially identical sensor is used for the material property value detector 12 and the flow detector 11, with the sensors being arranged at an angle that differs by 90° from the flow direction of the fluid to be measured. This allows the identical sensor to function as the material property value detector 12 or as the flow detector 11, thus reducing the manufacturing costs of the flowmeter 1.

[0034] On the other hand, the material property value detector 12 is provided with the first thermopile (first temperature detector in the material property value detector) 121 and the second thermopile (second temperature detector in the material property value detector) 122 for detecting the temperature of the fluid to be measured, and the microheater (heating section in the material property value detector) 123 for heating the fluid to be measured. The heating section 123 in the material property value detector, the first temperature detector 121 in the material property value detector, and the second temperature detector 122 in the material property value detector are arranged side by side in a direction orthogonal to the flow direction Q of the fluid to be measured in the material property value detector 12.The shapes of the heating section 123 in the material property value detector, the first temperature detector 121 in the material property value detector, and the second temperature detector 122 in the material property value detector are each substantially rectangular in plan view, and their respective longitudinal directions extend along the flow direction Q of the fluid to be measured. Furthermore, the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector are arranged symmetrically across the heating section 123 in the material property value detector and detect the temperature at symmetrical positions on both sides of the heating section 123 in the material property value detector.

[0035] Since the temperature distribution is unilateral downstream 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. By juxtaposing the first temperature detector 121 in the material property value detector, the heating section 123 in the material property value detector, and the second temperature detector 122 in the material property value detector in this order in the direction orthogonal to the flow direction of the fluid to be measured, the change in the output behavior of the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector due to the change in the temperature distribution can be reduced.Consequently, the effect of the change in temperature distribution due to the flow of the fluid to be measured can be reduced and the detection precision by the detector 12 of a value of the material properties can be improved.

[0036] Since the longitudinal direction of the heating section 123 in the material property value detector is arranged along the flow direction of the fluid to be measured, the heating section 123 in the material property value detector can heat the fluid to be measured to a large extent in the flow direction of the fluid to be measured. Therefore, even if the temperature distribution is lopsided due to the flow of the fluid to be measured downstream, the change in the output characteristics of the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector can be reduced. Consequently, the effect of the change in the temperature distribution due to the flow of the fluid to be measured can be reduced, and the detection precision by the material property value detector 12 can be improved.

[0037] Furthermore, since the longitudinal direction of the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector are arranged along the flow direction of the fluid to be measured, the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector can detect the temperature widely in the flow direction of the fluid to be measured. Therefore, even if the temperature distribution is lopsided due to the flow of the fluid to be measured downstream, the change in the output characteristics of the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector can be reduced.Consequently, the effect of the change in temperature distribution due to the flow of the fluid to be measured can be reduced and the detection precision by the detector 12 of a value of the material properties can be improved. <Funktioneller Aufbau>

[0038] Fig. Figure 8 is a block diagram showing the functional structure of the flowmeter. The flowmeter 1 is provided with the flow detector 11, the material property value detector 12, and the controller 13. The flow detector 11 is provided with a first temperature detector 111 in the flow detector and a second temperature detector 112 in the flow detector. The material property value detector 12 is provided with a first temperature detector 121 in the material property value detector, a second temperature detector 122 in the material property value detector, and a heating section 123 in the material property value detector.

[0039] The flow detector 11 detects a value indicative of the flow rate of the fluid to be measured based on temperature detection signals output from the first temperature detector 111 in the flow detector and the second temperature detector 112 in the flow detector. Specifically, the flow detector 11 calculates a difference between the temperature detection signal output from the first temperature detector 111 in the flow detector and the temperature detection signal output from the second temperature detector 112 in the flow detector, and determines a value indicative of the flow rate of the fluid to be measured based on the difference. The flow detector 11 then outputs the value indicative of the flow rate to the controller 13.

[0040] The material property value detector 12 outputs a temperature detection signal output by the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector to a flow calculation section 133. Specifically, the material property value detector 12 determines an average value of the temperature detection signals output by the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector. The heating section 123 in the material property value detector further changes the temperature, for example, according to the control of the controller 13.This allows the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector to determine the output values ​​before and after the temperature change of the heating section 123 in the material property value detector. The material property value detector 12 outputs the obtained output values ​​to the controller 13.

[0041] The controller 13 further includes a correction processing section 131, a characteristic value calculation section 132, and a flow rate calculation section 133. The flow rate calculation section 133 calculates the flow rate of the fluid to be measured based on the detection value of the flow rate detector 11. The characteristic value calculation section 132 calculates a characteristic value based on the detection value of the material property value detector 12. Specifically, the characteristic value calculation section 132 changes the temperature of the micro-heater of the material property value detector 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 factor. The correction processing section 131 corrects the flow rate calculated by the flow rate calculation section 133 using the characteristic value.The material property value detector 12 and the characteristic value calculation section 132 are collectively referred to as a characteristic value holding section. <Verarbeitung zur Durchflussmessung>

[0042] Fig. Figure 9 is a processing flowchart showing an example of flow measurement processing. As shown in Fig. As shown in Fig. 9, the flow detector 11 outputs temperature detection signals from the first temperature detector in the flow detector and from the second temperature detector 112 in the flow detector, and the flow calculation section 133 calculates the flow of the fluid to be measured ( Fig. 9: S1).

[0043] Specifically, the flow detector 11 outputs the temperature detection signal output by the first temperature detector 111 in the flow detector and the temperature detection signal output by the second temperature detector 112 in the flow detector. The flow calculation section 133 further calculates the difference between the two temperature detection signals and, based on the difference, calculates a value indicative of the flow rate of the fluid to be measured.

[0044] Generally known methods can be used to calculate the flow rate of the fluid to be measured based on the temperature detection signals output by the first temperature detector 111 in the flow detector and the second temperature detector 112 in the flow detector. The flow detector 11 outputs the calculated flow rate of the fluid to be measured to the controller 13.

[0045] The material property value detector 12 further performs processing to preserve the characteristic value (S2). In detail, the processing to preserve the characteristic value is described using Fig. 10 explained.

[0046] Fig. Fig. 10 is a processing flowchart showing an example of the processing for obtaining the characteristic value. The characteristic value calculation section 132 of the controller 13 causes the heating section 123 in the material property value detector of the material property value detector 12 to be heated to a first temperature ( Fig. 10: S11). Thereafter, the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector of the material property value detector 12 detect the first temperature (S12). This step can be performed, for example, based on the control by the controller 13. The rate of heat transfer through the fluid to be measured is determined by the material property values ​​such as thermal conductivity, thermal diffusivity, specific heat, etc. The thermal conductivity can be further determined by detecting the temperature difference between the heating section 123 in the material property value detector and the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector. For example, the larger the temperature difference, the higher the heat transfer rate.The larger the temperature difference between the heating section 123 in the material property value detector and the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector, the smaller the thermal conductivity becomes. Using this property, in this step, the temperature of the fluid to be measured is detected by the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector, which are arranged in a direction orthogonal to the flow direction of the fluid to be measured.

[0047] Next, the characteristic value calculation section 132 of the controller 13 causes the heating section 123 in the material property value detector of the material property value detector 12 to be heated to a second temperature (S13). Thereafter, the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector of the material property value detector 12 detect the second temperature (S14). This step can also be performed, for example, based on the control by the controller 13.In this way, values ​​indicative of the temperature detected by the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector before and after the temperature change of the heating section 123 in the material property value detector are obtained.

[0048] The characteristic value calculation section 132 further calculates the characteristic value using the detected temperature (S15). In this step, the sensor sensitivity ratio is calculated. The sensor sensitivity ratio represents the ratio of a sensor output value when a specific gas flows to a sensor output value when a reference gas flows, and is a characteristic value that represents thermal diffusivity. The sensor sensitivity ratio α is determined by the following formula (1): α=β×rT β is a predetermined coefficient. The element rT is the ratio of the detection values ​​output by the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector before and after the temperature change of the heating section 123 in the material property value detector.

[0049] Afterwards, there is a return to the processing of Fig. 9, wherein the controller 13 corrects the flow of the fluid to be measured calculated by the flow calculation section using the characteristic value ( Fig. 9: S3). Specifically, the controller 13 calculates the flow rate after the correction using the following formula (2): Output after correction = Output of the flow calculation section × α

[0050] In the embodiment, by using the ratio (rT) of the temperature detected by the thermopile before and after the change in the temperature of the micro-heater, the thermal diffusivity of the fluid to be measured can be more accurately measured. Here, the flow rate output by the thermal flow sensor is correlated with the thermal diffusivity. Consequently, after the flow rate correction processing according to this embodiment, each gas can be appropriately corrected. That is, the precision of the flow rate measurement can be improved with respect to the fluid to be measured with different thermal diffusivities.

[0051] Fig. Figure 11 is a graph showing the sensor sensitivity ratio on the ordinate and the thermal conductivity on the abscissa. As shown in Fig. For example, as shown in Figure 11, when multiple gas groups with different values ​​of material properties other than thermal conductivity are present, such as a mixed gas of different composition, it is not possible to determine which sensor sensitivity ratio should be used for correction simply by obtaining a specific thermal conductivity as the material property value. That is, with the method of using a set of the heating temperature of the micro heater and the detection temperature of the thermopile for correction, the correction based on two or more reference gases belonging to a specific gas group was not adequately performed with respect to multiple gas groups.Furthermore, with the difference of the detection values ​​ΔT outputted from the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector before and after the temperature change of the heating section 123 in the material property value detector, it is possible to calculate an appropriate characteristic value even with respect to the fluid to be measured for which a sufficiently high-precision calculation of the characteristic value is difficult.

[0052] Fig. Figure 12A is a graph plotting the sensor sensitivity ratio on the ordinate and ΔT on the abscissa. The sensor sensitivity ratio and ΔT also approach Fig. 11, whose sensor sensitivity ratio and thermal conductivity do not approach each other in a straight line, also adjusts in a straight line. Therefore, in this embodiment, the correction can also be made with respect to a group of gases whose thermal diffusivity is unknown. Fig. 12B is a graph showing the relationship between the average value of the outputs of the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector, and ΔT and rT before and after the temperature change of the heating section 123 in the material property value detector.

[0053] In this embodiment, the characteristic value is calculated using the ratio (rT) of the temperature detected by the thermopile before and after the change in the temperature of the micro-heater. In addition, in this embodiment, the difference (ΔT) of the temperature detected by the thermopile before and after the change in the temperature of the micro-heater can also be used to calculate the characteristic value. In this case, the sensor sensitivity ratio α is determined by the following formula (3): α=γ×rT+εΔT

[0054] Here, γ and ε are given coefficients.

[0055] This makes it possible to calculate the characteristic value using the ratio (rT) of the temperature detected by the thermopile before and after the change in the micro-heater temperature and the difference (ΔT) of the temperature detected by the thermopile before and after the change in the micro-heater temperature, which are correlated with the thermal diffusivity, and thus to calculate the characteristic value with high precision. In this embodiment, when the correlation between the thermal diffusivity of the fluid to be measured and the temperature difference (ΔT) detected by the thermopile before and after the change in the micro-heater temperature is very high, it is also possible to define the sensor sensitivity ratio α solely by the formula of ΔT (a value obtained by multiplying ΔT by a predetermined factor). [Modified examples]

[0056] In the above-described embodiment, the configuration in which the flow sensor of the flowmeter 1 assumes the fluid in the main flow path section 2 as the object to be measured is shown, but this is not limited to this example. For example, the flow sensor of the flowmeter 1 may assume the fluid in the secondary flow path branched from the main flow path section 2 as the object to be measured.

[0057] Fig. 13A is an exploded oblique view of the flowmeter 1 in this embodiment, and Fig. 13B is a perspective view of the Fig. 13A shown flowmeter 1. As shown in Fig. 13A and Fig. 13B, the flow meter 1 in the modified example is provided with the main flow path section 2, the secondary flow path section 3, a gasket 4, a circuit board 5 and a cover 6.

[0058] The main flow path section 2 is a tubular element penetrating in the longitudinal direction. On the inner peripheral surface of the main flow path section 2, an inlet opening (first inlet opening) 34 is formed upstream of the flow direction O of the fluid to be measured, and an outlet opening (first outlet opening) 35 is formed downstream of the flow direction O of the fluid to be measured.

[0059] In this embodiment, the length of the main flow path section 2 in the axial direction is about 50 mm, the diameter of the inner peripheral surface (inner diameter of the main flow path section 2) is about 20 mm, and the outer diameter of the main flow path section 2 is about 24 mm.

[0060] The secondary flow path section 3 is provided on the main flow path section 2, and a secondary flow path is formed inside and on the upper side thereof. Regarding the secondary flow path section 3, one end opens into an inlet port 34A, and the other end opens into an outlet port 35A. In the flow meter 1, the secondary flow path section 3 is formed by an inlet flow path 34, a material property value detection flow path 32, a flow rate detection flow path 33, and an outlet flow path 35.

[0061] The inlet flow path 34 is a flow path that causes a fluid to be measured flowing through the main flow path section 2 to flow in and branch into the material property value detection flow path 32 and the flow rate detection flow path 33. The inlet flow path 34 is formed in a direction perpendicular to the main flow path section 2 through the sub-flow path section 3, with one end opening into the inlet opening 34A and the other end opening at the top of the main flow path section 2 and flowing into the material property value detection flow path 32 and the flow rate detection flow path 33. This allows a portion of the fluid to be measured flowing through the main flow path section 2 to be branched via the inlet flow path 34 to the material property value detection flow path 32 and the flow rate detection flow path 33.

[0062] The material property value detection flow path 32 is a flow path having a substantially U-shaped longitudinal cross section formed on an upper surface of the sub-flow path portion 3 and extending in a direction parallel to the main flow path portion 2. Regarding the material property value detection flow path 32, a material property value detector 12 for detecting a material property value of the fluid to be measured is disposed at a portion extending in the longitudinal direction (direction parallel to the main flow path portion 2). One end of the material property value detection flow path 32 opens into the inlet port 34A via the inlet flow path 34, and the other end opens into the outlet port 35A via the outlet flow path 35.

[0063] The flow detection flow path 33 is a flow path with a substantially U-shaped longitudinal cross section formed on an upper surface of the sub-flow path portion 3 and extending in a direction parallel to the main flow path portion 2. The flow detection flow path 33 includes, at a portion extending in the longitudinal direction (direction parallel to the main flow path portion 2), the flow detection flow path 33 in which a flow detector 11 for detecting the flow rate of the fluid to be measured is arranged. One end of the flow detection flow path 33 opens into the inlet port 34A via the inlet flow path 34, and the other end opens into the outlet port 35A via the outlet flow path 35.

[0064] For convenience in explanation, in the drawings, the material property value detector 12 and the flow rate detector 11 and the circuit board 5 are shown in a separate state, but the material property value detector 12 and the flow rate detector 11 are arranged in the material property value detecting flow path 32 or the flow rate detecting flow path 33 in the state where they are mounted on the circuit board 5.

[0065] The drain flow path 35 is a flow path that allows a fluid to be measured, which has passed through the material property value detection flow path 32 or the flow rate detection flow path 33, to flow out into the main flow path section 2. The drain flow path 35 is formed in a direction perpendicular to the main flow path section 2 through the sub-flow path section 3, with one end opening into the drain opening 35A and the other end opening at the top of the main flow path section 2 and flowing into the material property value detection flow path 32 and the flow rate detection flow path 33. This allows the fluid to be measured, which has passed through the material property value detection flow path 32 or the flow rate detection flow path 33, to flow out into the main flow path section 2 via the drain flow path 35.

[0066] By branching the fluid to be measured flowing in from the same inlet port 34A into the material property value detection flow path 32 and the flow rate detection flow path 33, the material property value detector 12 and the flow rate detector 11 can detect the material property value or the flow rate based on the fluid to be measured under the same conditions such as temperature, concentration, etc. Consequently, the measurement precision of the flow meter 1 can be improved.

[0067] In the flowmeter 1, after inserting the gasket 4 into the bypass flow path section 3, the circuit board 5 is arranged and the circuit board 5 is fixed to the bypass flow path section 3 with the cover 6 to ensure the airtightness in the bypass flow path section 3.

[0068] Fig. 14 is a perspective view of the Fig. 13A shown bypass flow path section 3. As in Fig. As shown in Figure 14, with respect to the flow path 32 for detecting a material property value, one end opens in a substantially U-shaped manner into the inlet flow path 34, and the other end opens into the outlet flow path 35. Likewise, with respect to the flow path 33 for flow detection, one end opens in a substantially U-shaped manner into the inlet flow path 34, and the other end opens into the outlet flow path 35.

[0069] In addition, the two ends of the material property value detecting flow path 32 and the flow rate detecting flow path 33 join each other, and the material property value detecting flow path 32 and the flow rate detecting flow path 33 form a rectangular flow path at the top of the sub-flow path section 3.

[0070] In the flow meter 1, the flow path 32 for detecting a value of the material properties and the flow path 33 for detecting the flow rate each assume a square shape when viewed from a direction perpendicular to the top side of the secondary flow path section 3, and are formed at positions symmetrical to a connecting line between the flow path 34 to the inlet and the flow path 35 to the outlet.

[0071] In this embodiment, the length of one side of the flow path 32 for detecting a value of the material properties and the flow path 33 for detecting the flow rate is each about 4 mm.

[0072] In this embodiment, the shape of the material property value detection flow path 32 and the flow rate detection flow path 33 is square, but the present invention is not limited to this. Any shape of the material property value detection flow path 32 and the flow rate detection flow path 33 is possible as long as the material property value detector 12 and the flow rate detector 11 can be arranged, and the shape is determined according to the shape of the material property value detector 12 and the flow rate detector 11.

[0073] Consequently, for example, in the case where the size of the material property value detector 12 is smaller than the width of the material property value detection flow path 32, the width of the material property value detection flow path 32 can be adjusted to match the width of the material property value detector 12. In this case, the longitudinally extending portion of the material property value detection flow path 32 is formed as a straight line. The same applies to the flow path 33 for flow detection.

[0074] Fig. 15A is a plan view showing a schematic structure of the Fig. 13A and Fig. 13B shows a value of the material properties of the detector 12, and Fig. 15B is a plan view showing a schematic structure of the Fig. 13A and Fig. 13B. When the flow detector 11 is Fig. 15A and Fig. 15B, the material property value detecting flow path 32 and the flow rate detecting flow path 33 each have different widths of the flow path extending in the longitudinal direction, and the flow path width of the material property value detecting flow path 32 in which the material property value detector 12 is arranged is narrower than the flow path width of the flow rate detecting flow path 33 in which the flow rate detector 11 is arranged. With this, in the flow meter 1, the flow of the fluid to be measured branched into the material property value detecting flow path 32 and the flow rate detecting flow path 33 is each separately controlled.

[0075] Fig. 16 is a perspective view illustrating the flow of the fluid to be measured, which is in the Fig. 13A and Fig. 13B shown flow path 32 for detecting a value of the material properties and the flow path 33 for flow detection. As in Fig. 16, in this embodiment, the widths of the material property value detecting flow path 32 and the flow rate detecting flow path 33 are set such that the fluid to be measured is branched off into the material property value detecting flow path 32 at a flow rate P, and the fluid to be measured flows into the flow rate detecting flow path 33 at a flow rate Q.

[0076] The values ​​for 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. The widths of the flow path 32 for detecting a value of the material properties and the flow path 33 for detecting the flow rate are each predetermined such that the flow rate P takes a value within the detection range of the detector 12 of a value of the material properties and the flow rate Q takes a value within the detection range of the flow detector 11 in a normal use variant.

[0077] In this embodiment, the width of the flow path 32 for detecting a value of the material properties is about 0.4 mm and the width of the flow path 33 for flow detection is about 0.8 mm.

[0078] In this way, in the flowmeter 1, the flow of the fluid to be measured branched into the material property value detection flow path 32 and the flow rate detection flow path 33 can be controlled separately by separately adjusting the width of the flow path. Therefore, the flow of the fluid to be measured flowing in the material property value detection flow path 32 can be controlled according to the detection range of the material property value detector 12, and the flow of the fluid to be measured flowing in the flow rate detection flow path 33 can be controlled according to the detection range of the flow rate detector 11.

[0079] The material property value detector 12 can therefore detect a material property value of the fluid to be measured at an optimal flow rate corresponding to its detection range, thereby increasing the detection precision of the material property value detector 12.

[0080] The flow detector 11 can also detect the flow of the fluid to be measured at an optimal flow according to its own detection range and thus increase the detection precision of the flow detector 11.

[0081] In the modified example described above, as in Fig. 16, the configuration in which the material property value detecting flow path 32 and the flow rate detecting flow path 33 are each formed in a substantially U-shape will be described, but the present invention is not limited thereto. The shape of the material property value detecting flow path 32 and the flow rate detecting flow path 33 is not particularly limited, as long as their width is set to a width capable of controlling the flow rate of the fluid to be measured passing through the material property value detecting flow path 32 and the flow rate detecting flow path 33.

[0082] Fig. 17A to 17D are plan views showing modified examples of the flow path 32 for detecting a value of the material properties and the flow path 33 for detecting the flow rate, which are provided on the top side of the Fig. 16 shown secondary flow path section 3 are formed.

[0083] As in Fig. 17A, the flow path 32 for detecting a value of the material properties may be formed, for example, in a straight line and the flow path 33 for flow detection may be formed in a substantially U-shape.

[0084] As further stated in Fig. 17B to 17D, the material property value detecting flow path 32 may also be formed such that the fluid to be measured flows into the material property value detecting flow path 32 from a direction orthogonal to the direction in which the fluid to be measured flows into the flow rate detecting flow path 33.

[0085] In this case, the arrangement angles of the material property value detector 12 and the flow detector 11 may be the same, so that the step of mounting the material property value detector 12 and the flow detector 11 on the circuit board 5 in the manufacturing process of the flow meter 1 can be simplified.

[0086] In the modified example described above, as in Fig. 15A, the configuration is explained in which the material property value detector 12 is provided with the heating section 123 in the material property value detector which heats the fluid to be measured, and the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector which detect the temperature of the fluid to be measured, wherein the first temperature detector 121 in the material property value detector and the second temperature detector 122 in the material property value detector are arranged symmetrically about the heating section 123 in the material property value detector, but the present invention is not limited to this.

[0087] Fig. 18 is a plan view showing a schematic structure of a modified example of the Fig. 15A shows a value of the material properties. As shown in Fig. 18, the second temperature detector 122 in the material property value detector may be omitted, and the heating section 123 in the material property value detector and the first temperature detector 121 in the material property value detector may form one material property value detector 12a.

[0088] In this way, the material property value detector 12a can be realized by arranging the heating section in the material property value detector and the first temperature detector in the material property value detector in a direction orthogonal to the flow direction of the fluid to be measured. [Modified Example 2]

[0089] Another modified example of the flow meter according to the present invention is made on the basis of Fig. 19A to 19C. Elements corresponding to the above-described embodiments are denoted by the corresponding symbols, and explanations thereof are omitted. In the flowmeter according to the present modified example, the flow detector is arranged in the main flow path.

[0090] Fig. 19A is a perspective view of a flowmeter 1a according to the present modified example, Fig. 19B is a cross section of the Fig. 19A shown flowmeter 1a and Fig. 19C is a plan view of a Fig. 19A shown secondary flow path section 3a.

[0091] As in Fig. 19A to 19C, in the flowmeter 1a, an opening 37A is formed between the inlet opening 34A and the outlet opening 35A of the inner peripheral surface of a main flow path portion 2a.

[0092] In the secondary flow path portion 3a, a cell-shaped flow path 37a for flow detection is formed, in which the flow detector 11 is arranged, and the flow path 37a for flow detection opens into the opening 37A. Therefore, a fluid to be measured flowing through the main flow path portion 2a via the opening 37A flows into the flow detection flow path 37a, and the flow is detected by the flow detector 11.

[0093] By controlling and adjusting the size of the opening 37A, the flow of the fluid to be measured flowing from the main flow path section 2a into the flow path 37a for flow detection can be controlled.

[0094] The secondary flow path section 3a is formed by the inlet flow path 34, the material property value detection flow path 32 and the outlet flow path 35, wherein the material property value detection flow path 32 has, in a longitudinally extending flow path, the material property value detection flow path 32 in which the material property value detector 12 for detecting a material property value of the fluid to be measured is arranged.

[0095] In this way, in the flowmeter 1a, the material property value detector 12 is arranged in the secondary flow path section 3a, and the flow detector 11 is arranged in the primary flow path section 2a. Therefore, the flow in the flowmeter 1a can be controlled according to the detection range of the material property value detector 12.

[0096] Therefore, according to this embodiment, by reducing changes in the output behavior based on changes in the material properties of the fluid to be measured, the flow meter 1a capable of measuring the flow rate of the fluid to be measured with high precision can be realized. [Modified Example 3]

[0097] Another modified example of the flow meter according to the present invention is made on the basis of Fig. 20A and Fig. 20B. The elements corresponding to the embodiments are denoted by the corresponding symbols, and their explanations are omitted.

[0098] The flow meter according to the modified example differs from the flow meters described above in that it has two independent secondary flow paths.

[0099] Fig. Fig. 20A is a perspective view of the flowmeter 1b according to this embodiment, and Fig. 20B is a plan view of the Fig. 20A shown secondary flow path section 3.

[0100] As in Fig. 20A and Fig. 20B, the bypass flow path portion 3b in the flow meter 1b has two bypass flow path portions formed inside and on the top thereof.

[0101] The first secondary flow path section is formed by an inlet flow path 34b, a material property value detection flow path 32b, and an outlet flow path 35b, wherein the material property value detector 12 for detecting a material property value of the fluid to be measured is arranged in a longitudinally extending flow path in the material property value detection flow path 32b.

[0102] The second secondary flow path section is formed by an inlet flow path 34B, a flow path 33B for flow detection and an outlet flow path 35B, wherein in the flow path 33B for flow detection the flow detector 11 for flow detection of the fluid to be measured is arranged in a flow path extending in the longitudinal direction.

[0103] In this way, the bypass flow path section 3b of the flow meter 1b has two independent bypass flow paths, with the material property value detector 12 located in the first bypass flow path section and the flow detector 11 located in the second bypass flow path section. Therefore, the flow in the flow meter 1b can be controlled separately according to the detection range of the material property value detector 12 and the flow detector 11.

[0104] Therefore, according to this embodiment, by reducing changes in the output behavior based on changes in the material properties of the fluid to be measured, the flow meter 1b capable of measuring the flow rate of the fluid to be measured with high precision can be realized. [Modified Example 4]

[0105] Another modified example of the flow meter according to the present invention is made on the basis of Fig. 21A to 21C. Elements corresponding to the embodiments are denoted by the corresponding symbols, and explanations thereof are omitted.

[0106] The flowmeter according to the present modified example differs from the flowmeters described above in that the flow path for detecting a value of the material properties is formed in the flow path for flow detection.

[0107] Fig. 21A is a perspective view of the flowmeter 1c in this embodiment, Fig. 21 B is a perspective view of the Fig. 21A shown secondary flow path section 3c, and Fig. 21C is a plan view of the Fig. 21A shown secondary flow path section 3c.

[0108] As in Fig. 21A to 21C, in the flow meter 1c, the secondary flow path section 3c is formed by the flow path 34 to the inlet, a flow path 32c for detecting a value of the material properties, a flow path 33c for flow detection and the flow path 35 to the outlet.

[0109] In the secondary flow path section 3c, the flow path 32c for detecting a value of the material properties is formed in the flow path 33c for flow detection, wherein the flow detector 11 is arranged upstream of the flow direction of the fluid to be measured and the detector 12 of a value of the material properties is arranged downstream of the flow direction.

[0110] Here, the flow path 32c for detecting a value of the material properties by a flow control element 40 for controlling the flow of the fluid to be measured is separate from the flow path 33c for flow detection, and the detector 12 of a value of the material properties is arranged in the flow control element 40.

[0111] The flow control element 40 serves to control the flow of a fluid to be measured passing through the flow path 32c for detecting a material property value. It is formed by a first side wall 40a and a second side wall 40b. The first side wall 40a and the second side wall 40b are each plate-like elements of a substantially U-shape and are arranged at predetermined intervals with the respective ends facing each other.

[0112] 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 interior of the flow control element 40, ie, the flow path 32c for detecting a value of the material properties, can be adjusted.

[0113] In this way, in the flowmeter 1c, the bypass flow path section 3c is provided with the flow control element 40, and the material property value detection flow path 32c is provided in the flow control element 40, so that it is possible to provide the material property value detection flow path 32c at any position in the bypass flow path section 3c. Furthermore, by providing the flow control element 40, the flow of the fluid to be measured passing through the material property value detection flow path 32c can be easily controlled.

[0114] Even if the material property value detection flow path 32c is formed in the flow rate detection flow path 33c in this way, the flow rate can be controlled separately according to the detection range of the material property value detector 12 and the flow rate detector 11.

[0115] Therefore, according to this embodiment, by reducing changes in the output behavior based on changes in the material properties of the fluid to be measured, the flow meter 1c capable of measuring the flow rate of the fluid to be measured with high precision can be realized. [Modified Example 5]

[0116] Fig. 22A to 22C illustrate an example of a multi-stage branch type according to another modified example. Fig. 22C shows the connection point of a main flow path section 2d and a flow meter 1d. Fig. 22B is an enlarged view of the Fig. 22C shown as a dashed rectangle. Fig. 22A is an AA cross-section of a unit 1000 in Fig. 22C. As enlarged in Fig. 22B, in the present modified example, a secondary flow path section 3d is provided along the flow direction of the main flow path section 2d, which is thinner (smaller in cross section) than the main flow path section 2d. The secondary flow path section 3d branches off into a main flow path 2e, which penetrates along the main flow path section 2d, and a secondary flow path section 3e, which connects almost perpendicularly to the secondary flow path section 3d. Then, the secondary flow path section 3e branches off, as shown in Fig. 22A, into a sub-flow path section 3f in which the flow detector 11 is provided, and a sub-flow path section 3g in which the material property value detector 12 is provided.

[0117] According to the modified example with the bypass flow path described above, the flow rate can be measured with the small flow meter 1d regardless of the flow rate of the main flow path section 2d (i.e., the thickness (cross-sectional area) of the main flow path section 2d). Furthermore, according to the modified example with the bypass flow path described above, the intrusion of dust into a sensor chip can be suppressed and the measurement precision can be improved, and the amount of intrusion of dust can be controlled by the three-stage branch structure as in the Fig. 22A to 22C.

[0118] As with the Fig. In the unit 1000 shown in Figure 22, a member including, for example, the secondary flow path section 3f with the provided flow detector 11 and the secondary flow path section 3g with the provided material property value detector 12 can also be formed as a detachable member. In this way, it is possible to provide a member attachable to the main flow path section 2 with various flow rates and shapes, thus reducing costs.

[0119] Fig. Figure 23 is a cross-sectional view illustrating another modified example. In the example of Fig. 23, a flow detector 11 and a material property value detector 12 are arranged on the front and back of the circuit board, respectively. A secondary flow path is also provided through the circuit board. Not limited to the tubular secondary flow path variant, a Fig.23 shown branch structure can be applied.

[0120] Hereinafter, the features of the present invention are indicated with symbols of the drawings so that the features of the present invention can be compared with the embodiments. <Erfindung 1 >

[0121] Flow meter (1), characterized by: a flow detector (11) designed to detect a flow of a fluid to be measured flowing through a main flow path, a characteristic value obtaining section comprising: a heating section (123) designed to heat the fluid to be measured, and a temperature detector (121, 122) designed to detect the temperature of the fluid to be measured and designed to obtain a characteristic value of the fluid to be measured, and a flow correction section (131) configured to correct the flow of the fluid to be measured, which is calculated on the basis of a detection signal output from the flow detector (11), using the characteristic value of the fluid to be measured obtained by the characteristic value obtaining section, wherein the heating section (123) and the temperature detector (121, 122) are arranged side by side in a direction orthogonal to the flow direction of the fluid to be measured, and wherein the characteristic value obtaining section obtains the characteristic value from the ratio of the temperature of the fluid to be measured detected by the temperature detector (121, 122) before and after the change in the temperature of the heating section (123). <Erfindung 14>

[0122] Method for measuring the flow of a fluid to be measured using a flow meter (1) comprising: a flow detector (11) comprising: a heating section (113) designed to heat the fluid to be measured, and a temperature detector (111, 112) designed to detect the temperature of the fluid to be measured, which are arranged side by side in a flow direction of the fluid to be measured, and designed to detect a flow of the fluid to be measured flowing through a main flow path, and a characteristic value obtaining section comprising: a second heating section (123) designed to heat the fluid to be measured, and a second temperature detector (121, 122) designed to detect the temperature of the fluid to be measured, which are arranged side by side in a direction orthogonal to the flow of the fluid to be measured, and designed to obtain a characteristic value of the fluid to be measured, characterized by: a flow detection step (S1) in which the flow detector (11) detects the flow of the fluid to be measured flowing through the main flow path, a first temperature measuring step (S12) in which the temperature of the fluid to be measured is measured by the second temperature detector (121, 122), a temperature changing step (S13) in which the temperature of the second heating section (123) is changed, a second temperature measuring step (S14) in which, after the temperature change step (S13), the temperature of the fluid to be measured is measured by the second temperature detector (121, 122), a characteristic value obtaining step (S15) in which the characteristic value is obtained using a ratio between the temperature of the fluid to be measured, which is measured in the first temperature measuring step (S12), and the temperature of the fluid to be measured, which is measured in the second temperature measuring step, and a correction step (S3) in which the flow of the fluid to be measured is corrected by multiplying the flow of the fluid to be measured, which is detected in the flow detection step (S1), by the characteristic value. <Erfindung 15>

[0123] Flow measurement program comprising a flow meter (1) comprising: a flow detector (11) comprising: a heating section (113) designed to heat a fluid to be measured, and a temperature detector (111, 112) designed to detect the temperature of the fluid to be measured, which are arranged side by side in a flow direction of the fluid to be measured, and designed to detect a flow of the fluid to be measured flowing through a main flow path, and a characteristic value obtaining section comprising: a second heating section (123) designed to heat the fluid to be measured, and a second temperature detector (121, 122) designed to detect the temperature of the fluid to be measured, which are arranged side by side in a direction orthogonal to the flow of the fluid to be measured, and designed to obtain a characteristic value of the fluid to be measured, to measure the flow of the fluid to be measured, whereby an information processing device is caused to carry out: a flow detection step (S1) in which the flow detector (11) detects the flow of the fluid to be measured flowing through the main flow path, a first temperature measuring step (S12) in which the temperature of the fluid to be measured is measured by the second temperature detector (121, 122), a temperature changing step (S13) in which the temperature of the second heating section (123) is changed, a second temperature measuring step (S14) in which, after the temperature change step (S13), the temperature of the fluid to be measured is measured by the second temperature detector (121, 122), a characteristic value obtaining step (S15) in which the characteristic value is obtained using a ratio between the temperature of the fluid to be measured, which is measured in the first temperature measuring step (S12), and the temperature of the fluid to be measured, which is measured in the second temperature measuring step, and a correction step (S3) in which the flow of the fluid to be measured is corrected by multiplying the flow of the fluid to be measured, which is detected in the flow detection step (S1), by the characteristic value.

Claims

[1] Flowmeter, characterized by : a flow detector designed to detect a flow of a fluid to be measured flowing through a main flow path, a characteristic value obtaining section comprising: a heating section configured to heat the fluid to be measured, and a temperature detector configured to detect the temperature of the fluid to be measured and to obtain a characteristic value of the fluid to be measured, and a flow correction section configured to correct the flow of the fluid to be measured, which is calculated on the basis of a detection signal output from the flow detector, using the characteristic value of the fluid to be measured obtained by the characteristic value obtaining section, wherein the heating section and the temperature detector are arranged side by side in a direction orthogonal to the flow direction of the fluid to be measured, and wherein the characteristic value obtaining section obtains the characteristic value from the ratio of the temperature of the fluid to be measured detected by the temperature detector before and after a change in the temperature of the heating section. [2] Flowmeter according to claim 1, characterized by that the characteristic value obtaining section receives the characteristic value from a difference and a ratio of the temperature of the fluid to be measured detected by the temperature detector before and after the change in the temperature of the heating section. [3] Flowmeter according to claim 1 or 2, characterized by , that the characteristic value is a value obtained by multiplying the difference and / or the ratio of the temperature of the fluid to be measured detected by the temperature detector before and after the change in the temperature of the heating section by a predetermined factor, and the flow correction section corrects the flow of the fluid to be measured by multiplying the detection signal output by the flow detector by the characteristic value. [4] Flowmeter according to one of claims 1 to 3, characterized byin that a secondary flow path section is further provided which is branched off from the main flow path in that one end opens into a first inlet opening which is opened in the main flow path and the other end opens into a first outlet opening which is opened in the main flow path, and has a characteristic value detection flow path in which the temperature detector of the characteristic value obtaining section is arranged, wherein the flow detector is arranged in a position which is different from the characteristic value detection flow path. [5] Flowmeter according to claim 4, characterized by that the temperature detector of the characteristic value obtaining section and the flow detector are provided on a flow detection element which is detachably provided from a member forming the main flow path or the secondary flow path section. [6] Flowmeter according to claim 4 or 5, characterized by , that the secondary flow path section comprises: a flow detection flow path in which the flow detector is arranged, a first secondary flow path section branched off from the secondary flow path section by one end opening into a first inlet opening opened in the main flow path and the other end opening into a first outlet opening opened in the main flow path, and a second secondary flow path section branched off from the first secondary flow path section by one end opening into a second inlet opening opened in the first secondary flow path section and the other end opening into a second outlet opening opened in the first secondary flow path section, wherein both the flow rate detection flow path and the characteristic value detection flow path are formed by further branching off from the second secondary flow path section in that one end opens into a third inlet opening which is open in the second secondary flow path section and the other end opens into a third outlet opening which is open in the second secondary flow path section. [7] Flowmeter according to claim 4 or 5, characterized by , that the secondary flow path section further comprises a flow detection flow path in which the flow detector is arranged, wherein the flow detection flow path has one end opening into the first inlet opening and the other end opening into the first outlet opening, and a fluid to be measured flowing in from the first inlet opening, branching off to the characteristic value detection flow path and the flow detection flow path. [8] Flowmeter according to claim 4 or 5, characterized by , that the secondary flow path section further comprises a flow detection flow path in which the flow detector is arranged, wherein the characteristic value detection flow path is provided in the flow detection flow path, and allows a portion of the fluid to be measured flowing through the flow detection flow path to flow into the characteristic detection flow path. [9] Flowmeter according to claim 4 or 5, characterized by , that the secondary flow path section further comprises a flow detection flow path in which the flow detector is arranged, wherein the flow detection flow path has one end opening into a fourth inlet opening open in the main flow path and the other end opening into a fourth outlet opening open in the main flow path. [10] Flowmeter according to one of claims 1 to 5, characterized by , that the flow detector is located in the main flow path. [11] Flowmeter according to one of claims 1 to 10, characterized by that the heating section is arranged such that the longitudinal direction of the heating section runs along the flow direction of the fluid to be measured. [12] Flowmeter according to one of claims 1 to 11, characterized by that the temperature detector is arranged such that the longitudinal direction of the temperature detector runs along the flow direction of the fluid to be measured. [13] Flowmeter according to claim 4 or 5, characterized by , that the secondary flow path section further comprises a flow detection flow path in which the flow detector is arranged, wherein the flow detection flow path and the characteristic value detection flow path are formed by arranging a circuit board parallel to the flow direction of the fluid to be measured in the secondary flow path section or in a flow path branched off from the secondary flow path section, in order to branch off the secondary flow path section or the flow path branched off from the secondary flow path section, wherein the flow detector and the temperature detector of the characteristic value obtaining section are provided on one surface and the opposite surface of the circuit board, respectively. [14] A method for measuring the flow of a fluid to be measured using a flowmeter, comprising: a flow detector comprising: a heating section configured to heat the fluid to be measured, and a temperature detector configured to detect the temperature of the fluid to be measured, which are arranged side by side in a flow direction of the fluid to be measured, and configured to detect a flow of the fluid to be measured flowing through a main flow path, and a characteristic value obtaining section comprising: a second heating section configured to heat the fluid to be measured, and a second temperature detector configured to detect the temperature of the fluid to be measured, which are arranged side by side in a direction orthogonal to the flow of the fluid to be measured, and configured to obtain a characteristic value of the fluid to be measured, characterized by : a flow detection step in which the flow detector detects the flow of the fluid to be measured flowing through the main flow path, a first temperature measuring step in which the temperature of the fluid to be measured is measured by the second temperature detector, a temperature change step in which the temperature of the second heating section is changed, a step for measuring a second temperature, in which, after the temperature change step, the temperature of the fluid to be measured is measured by the second temperature detector, a characteristic value obtaining step in which the characteristic value is obtained using a ratio between the temperature of the fluid to be measured, which is measured in the step of measuring a first temperature, and the temperature of the fluid to be measured, which is measured in the step of measuring a second temperature, and a correction step in which the flow of the fluid to be measured is corrected by multiplying the flow of the fluid to be measured, which is detected in the flow detection step, by the characteristic value. [15] Flow measurement program that includes a flow meter that includes: a flow detector comprising: a heating section configured to heat a fluid to be measured, and a temperature detector configured to detect the temperature of the fluid to be measured, which are arranged side by side in a flow direction of the fluid to be measured, and configured to detect a flow of the fluid to be measured flowing through a main flow path, and a characteristic value obtaining section comprising: a second heating section configured to heat the fluid to be measured, and a second temperature detector configured to detect the temperature of the fluid to be measured, which are arranged side by side in a direction orthogonal to the flow of the fluid to be measured, and configured to obtain a characteristic value of the fluid to be measured, to measure the flow of the fluid to be measured, whereby an information processing device is caused to carry out: a flow detection step in which the flow detector detects the flow of the fluid to be measured flowing through the main flow path, a first temperature measuring step in which the temperature of the fluid to be measured is measured by the second temperature detector, a temperature change step in which the temperature of the second heating section is changed, a step for measuring a second temperature, in which, after the temperature change step, the temperature of the fluid to be measured is measured by the second temperature detector, a characteristic value obtaining step in which the characteristic value is obtained using a ratio between the temperature of the fluid to be measured, which is measured in the step of measuring a first temperature, and the temperature of the fluid to be measured, which is measured in the step of measuring a second temperature, and a correction step in which the flow of the fluid to be measured is corrected by multiplying the flow of the fluid to be measured, which is detected in the flow detection step, by the characteristic value.

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