JP2006105847A - Thermal type flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal type flowmeter (boundary layer flowmeter) capable of accurate flow measurement even in a wide flow measuring range wherein the flow state is shifted from a laminar flow region to a transitional region and then to a turbulent flow region in accompany with an increase of a fluid flow rate in a conventional case. <P>SOLUTION: This flowmeter has a constitution wherein a turbulent flow accelerator such as a coil 14, an annulus, a projection or a twisted tape is provided inside a part to be heated by a heater 11 of a pipe 15, to thereby disturb the flow of a fluid flowing in the pipe 15 by the turbulent flow accelerator, and the fluid is put into a turbulent flow state in the whole range of a prescribed flow measuring range of the fluid. Otherwise, the fluid may be put into the turbulent flow state in the whole range of the prescribed flow measuring range, by allowing the pipe to have a structure of a plurality of steps having a plurality of pipe parts having different tube diameters, by forming at least a pipe part to be heated by the heater of the pipe to be a spiral pipe, by forming the pipe part to be heated by the heater of the pipe to be a bent pipe, or by arranging a fluid collision member in the pipe. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal flow meter, and more specifically to a boundary layer flow meter which is a kind of a thermal flow meter.

  The structure and measurement principle of the thermal flow meter are as follows. The thermal flow meter in the following text indicates a boundary layer flow meter.

  FIG. 10 shows a configuration diagram of a conventional thermal flow meter. As shown in the figure, the thermal flow meter includes a heater 2 that heats a pipe 1 through which a fluid (for example, water) flows, and a pipe wall portion (measurement point 1a) of the pipe 1 that is located upstream of the heater 2. ) And a temperature sensor 4 such as a resistance thermometer that measures the temperature of the wall portion (measurement point 1b) of the pipe 1 heated by the heater 2. Have. In this case, the temperature sensor 3 is disposed at a position sufficiently away from the heater 2, and the temperature sensor 4 is disposed immediately inside the heater 2 as illustrated (directly below or directly above) or downstream of the heater 2. Therefore, the pipe wall temperature T1 measured by the temperature sensor 3 is less affected by the heater 2, and the temperature distribution (fluid temperature and pipe wall temperature) in the radius r direction of the pipe 1 is almost fluid as shown in FIG. Since the temperature is equal to the temperature, the difference between the tube wall temperature T1 measured by the temperature sensor 3 and the tube wall temperature T2 measured by the resistance temperature detector 4 depends on the heating amount of the heater 2 and the heat transfer coefficient of the fluid. To do. Therefore, when the heating amount of the heater 2 is known, the heat transfer coefficient of the fluid can be evaluated by the main body system, and finally the flow velocity (flow rate) of the fluid which is an influencing factor on the heat transfer coefficient can be obtained. .

More specifically, if the amount of heat input to heat from the temperature measuring point 1a of the temperature sensor 3 to the temperature measuring point 1b of the temperature sensor 4 is sufficiently small, the fluid temperature in the heater heating unit is measured by the temperature sensor 3. It can be regarded as equivalent to the upstream pipe wall temperature T1. Therefore, the relationship between the tube wall temperature (fluid temperature) T1 of the heater heating portion, the tube wall temperature T2, and the heat generation amount of the heater 2 is as follows.
q = h × (T2-T1)
q = Q / A
Here, q (W / m ² ) is the heat flux, h (W / m ² · k) is the heat transfer coefficient between the tube wall / fluid, Q (W) is the heating value of the heater, and A (m ² ) is the heater Heating area. The heat transfer coefficient h is generally expressed as h∝Re ^m · Pr ⁿ , where Reynolds number Re and Prandtl number are Pr.
Therefore, if the fluid physical properties and the pipe diameter are known, it is a function of the fluid flow velocity u (m / s). That is,
h = f (u)
Therefore, the flow velocity u is obtained by the following equation from the heat flux q obtained from the heater heat generation amount Q and the heater heating area A and the tube wall temperatures T1 and T2 obtained from the temperature sensors 3 and 4. Further, the flow rate of the fluid is obtained from the flow velocity u, the cross-sectional area of the pipe 1 and the density of the fluid.
u = f ⁻¹ (h) = f ⁻¹ {q / (T2−T1)}

  As a prior art document describing a thermal flow meter, for example, there is Patent Document 1 below.

JP-A-5-79875

  In the above prior art documents, a conventional thermal flow meter is provided with a cooling mechanism for preventing fluid overheating. However, a conventional thermal flow meter including this basically has a fluid flow measurement range. In a wide case, the fluid flow state (flow state) itself shifts from a laminar flow region to a transition region, and finally to a turbulent flow region as the fluid flow velocity (flow rate) increases, so the fluid flow rate and the heat transfer coefficient (ie thermal The relationship with the output of the flowmeter is not unique. In other words, as shown in FIG. 11, the relationship between the fluid flow rate (flow state) and the heat transfer coefficient, when the flow state shifts to the laminar flow region, transition region, and turbulent flow region as the fluid flow rate increases, There is no linearity in the relationship. For this reason, it has been difficult for the conventional thermal flow meter (boundary layer flow meter) to perform accurate flow measurement in a wide flow measurement range.

  Therefore, in view of the above circumstances, the present invention can accurately measure the flow rate even in a wide flow rate measurement range in which the flow state transitions to a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases. It is an object of the present invention to provide a thermal flow meter (boundary layer flow meter) capable of performing the above.

  The thermal flow meter of the first invention that solves the above problems includes a heating means for heating a pipe, and a temperature of a pipe wall portion of the pipe or a temperature of a fluid flowing in the pipe at a position upstream of the heating means. A thermal flow meter having first temperature measuring means for measuring the temperature and second temperature measuring means for measuring the temperature of the pipe wall portion of the pipe heated by the heating means, A turbulent flow promoting body is provided inside the part heated by the heating means, and the turbulent flow promoting body disturbs the flow of the fluid flowing in the pipe so that the fluid flows over the entire predetermined flow rate measurement range of the fluid. It is characterized by having a turbulent state.

  The thermal flow meter of the second invention is the thermal flow meter of the first invention, wherein the turbulence promoting body is a coil.

  The thermal flow meter of the third invention is the thermal flow meter of the first invention, wherein the turbulence promoting body is a plurality of rings arranged at intervals in the fluid flow direction. And

  The thermal flow meter according to a fourth aspect of the present invention is the thermal flow meter according to the first aspect, wherein the turbulence promoting body is a protrusion projecting from the inner surface of the pipe.

  The thermal flow meter of the fifth invention is the thermal flow meter of the first invention, wherein the turbulent flow promoting body is a twisted tape.

  The thermal flow meter of the sixth aspect of the invention measures the temperature of the pipe wall portion of the pipe or the temperature of the fluid flowing in the pipe at a position upstream of the heating means and heating means for heating the pipe. A thermal flow meter having a first temperature measuring means and a second temperature measuring means for measuring a temperature of a pipe wall portion of the pipe heated by the heating means, wherein the pipe has a pipe diameter By using a multi-stage structure having a plurality of different pipe portions, the fluid is turbulent in the entire range of a predetermined flow rate measurement range of the fluid flowing in the pipe, and the heating means has a different pipe diameter. It arrange | positions at each of several piping parts, and a said 1st temperature measurement means is upstream from the heating means arrange | positioned at the piping part located in the most upstream among the several piping parts from which the said pipe diameter differs. The second temperature measuring means is disposed on the tube Characterized in that disposed in each of the different piping.

  A thermal flow meter according to a seventh aspect of the present invention measures a heating means for heating a pipe and a temperature of a pipe wall portion of the pipe or a temperature of a fluid flowing in the pipe at a position upstream of the heating means. A thermal flow meter having first temperature measuring means and second temperature measuring means for measuring the temperature of the pipe wall portion of the pipe heated by the heating means, wherein at least the heating means of the pipe The pipe portion heated by the above is a spiral pipe, which disturbs the flow of the fluid flowing in the spiral pipe and makes the fluid turbulent in the entire range of a predetermined flow rate measurement range of the fluid. To do.

  The thermal flow meter according to the eighth aspect of the invention measures the temperature of the pipe wall portion of the pipe or the temperature of the fluid flowing in the pipe at a position upstream of the heating means and heating means for heating the pipe. A thermal flow meter having a first temperature measuring means and a second temperature measuring means for measuring a temperature of a pipe wall portion of the pipe heated by the heating means, wherein the heating means of the pipe By making the pipe part to be heated into a bend pipe, the flow of the fluid flowing in the bend pipe is disturbed to make the fluid turbulent in the entire range of a predetermined flow rate measurement range of the fluid. .

  A thermal flow meter according to a ninth aspect of the invention is arranged in a pipe, and the fluid flowing in the pipe collides with the fluid in a turbulent state over the entire predetermined flow rate measurement range of the fluid. A fluid impinging member, a heating means for heating the fluid impinging member, and a temperature of a pipe wall portion of the pipe or a temperature of the fluid flowing in the pipe at a position upstream of the heating means. It has temperature measuring means and second temperature measuring means for measuring the temperature of the fluid collision member heated by the heating means.

According to the thermal flow meter of the first, second, third, fourth, or fifth invention, a turbulent flow promoting body such as a coil, a ring, a protrusion, or a twisted tape is heated by a heating means of the pipe. Provided inside the part, the turbulence promoting body is configured to disturb the flow of the fluid flowing in the pipe so that the fluid is in a turbulent state in the entire range of the predetermined flow rate measurement range of the fluid. Therefore, the predetermined flow rate measurement range, that is, a relatively wide flow rate measurement range in which the flow state transitions to a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases unless a turbulence promoter is provided. The fluid can be in a turbulent state in the entire range. Accordingly, the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the pipe wall / fluid) can be provided with linearity over the entire range of the predetermined flow rate measurement range, and the fluid flow rate and the heat transfer coefficient (ie, heat transfer rate). The relationship with the output of the flow meter is unique. For this reason, the flow rate measurement range is wide and accurate flow rate measurement is possible.
As the turbulent flow promoter, the use of a coil is the most desirable because it is inexpensive because of its ease of installation and availability.

  Moreover, according to the thermal flow meter of the sixth invention, the pipe has a plurality of stages having a plurality of pipe portions having different pipe diameters, so that a predetermined flow rate measurement range of the fluid flowing in the pipe can be obtained. The fluid is in a turbulent state over the entire range, the heating means is disposed in each of the plurality of pipe parts having different pipe diameters, and the first temperature measurement means is provided for the plurality of pipe parts having different pipe diameters. The second temperature measuring means is arranged on each of the plurality of pipe parts having different pipe diameters, and arranged on the upstream side of the heating means arranged on the pipe part located on the most upstream side. Therefore, the predetermined flow rate measurement range, that is, a relatively wide flow rate in which only the pipe portion having a relatively large pipe diameter moves from a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases. Turbulent fluid flow over the entire measurement range It can be. Therefore, linearity can be given to the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the pipe wall / fluid) over the entire range of the predetermined flow rate measurement range. Relationship with the output of the flow meter). Moreover, even when the fluid flow rate is increased, the heating amount of the heating means is not required to be increased, and the pipe wall temperature measured by the second temperature measuring means and the first temperature measuring means are used in a pipe portion having a large pipe diameter. The difference from the measured fluid temperature or tube wall temperature increases. For this reason, the flow rate measurement range is wide and the flow rate can be accurately measured without increasing the cost.

  According to the thermal flow meter of the seventh aspect of the invention, at least the pipe portion heated by the heating means of the pipe is a spiral pipe, so that the flow of the fluid flowing in the spiral pipe is disturbed. Since the fluid is in a turbulent flow state in the entire range of the predetermined flow rate measurement range, the flow state is increased as the fluid flow rate is increased unless the flow rate measurement range of the fluid, that is, the pipe is a spiral tube. Since the fluid can be in a turbulent state over the entire range of a relatively wide flow rate measurement range that transitions to the laminar flow region, transition region, and turbulent flow region, the fluid flow rate and heat Linearity can be given to the relationship between the transfer rate (heat transfer rate between the tube wall / fluid), and the relationship between the fluid flow rate and the heat transfer rate (ie, the output of the thermal flow meter) is unique. For this reason, the flow rate measurement range is wide and accurate flow rate measurement is possible.

  According to the thermal flow meter of the eighth aspect of the invention, the pipe portion heated by the heating means of the pipe is a bend pipe, thereby disturbing the flow of the fluid flowing in the bend pipe, and Since the fluid is in a turbulent flow state over the entire flow rate measurement range, the fluid flow rate increases as the fluid flow rate increases unless the predetermined flow rate measurement range of the fluid, i.e., the heating part of the pipe, is a bend pipe. The fluid can be in a turbulent state over the entire range of a relatively wide flow rate measurement range in which the state shifts to a laminar flow region, a transition region, and a turbulent flow region. Since the relationship between the heat transfer coefficient (the heat transfer coefficient between the tube wall and the fluid) can be made linear, the relationship between the fluid flow rate and the heat transfer coefficient (that is, the output of the thermal flow meter) is unique. . For this reason, the flow rate measurement range is wide and accurate flow rate measurement is possible.

  According to the thermal flow meter of the ninth aspect of the present invention, when the fluid flowing in the piping collides with the fluid, the fluid is turbulently flown over the entire predetermined flow rate measurement range of the fluid. Since the fluid collision member is in a state, the predetermined flow rate measurement range of the fluid, that is, if the fluid collision member is not arranged in the pipe, the flow state is increased as the fluid flow rate increases, The fluid can be in a turbulent state over the entire range of a relatively wide flow rate measurement range that shifts to the turbulent flow region, and the fluid flow rate and the heat transfer coefficient (tube wall / Since the linearity can be given to the relationship with the heat transfer coefficient between the fluids, the relationship between the fluid flow rate and the heat transfer coefficient (that is, the output of the thermal flow meter) is unique. For this reason, the flow rate measurement range is wide and accurate flow rate measurement is possible.

  Embodiments of the present invention will be described below in detail with reference to the drawings. The thermal flow meter of the present invention can be widely applied as a flow meter used in various places such as a space station.

<Embodiment 1>
1 to 5 are configuration diagrams of a thermal flow meter (boundary layer flow meter) according to Embodiment 1 of the present invention, and these thermal flow meters are all provided with a turbulent flow promoting body in a pipe. It is a thing.

  The thermal flow meter shown in FIG. 1 includes a heater 11 as a heating means, a temperature sensor 12 such as a resistance temperature detector or a thermocouple as a first temperature measurement means, and a temperature measurement as a second temperature measurement means. A temperature sensor 13 such as a resistor or a thermocouple, and a coil 14 as a turbulence promoting body, and a flow velocity (flow rate) of a fluid such as water flowing in the pipe 15 as indicated by an arrow A in FIG. ).

  The heater 11 is mounted on the outer peripheral surface 15a of the pipe 15 and heats the pipe 15 (pipe wall). The heater 11 is an electric heater and is connected to a heater power source (not shown). Therefore, the heater 11 generates heat by the power supplied from the heater power source and heats the pipe 15. The heating amount of the heater 15 can be determined as appropriate by, for example, measuring the amount of power supplied from the heater power source to the heater 15 with a wattmeter.

  The temperature sensor 12 is installed on the pipe wall of the pipe 15 on the upstream side (hereinafter simply referred to as the upstream side) of the fluid flow direction from the installation position of the heater 15, and the temperature T1 of the pipe wall part (measurement point 15c) is measured. taking measurement. In this case, it is conceivable to directly measure the temperature of the fluid by the temperature sensor 12, but for that purpose, the temperature sensor 12 must be inserted into the pipe 15, and the temperature sensor 12 becomes a resistance against the flow of the fluid. Therefore, it is desirable to measure the tube wall temperature T1 by the temperature sensor 12. Since the temperature sensor 12 is disposed at a position sufficiently away from the heater 11, the tube wall temperature T <b> 1 measured by the temperature sensor 12 is less affected by the heater 11 and is substantially equal to the temperature of the fluid flowing in the pipe 15. In other words, the temperature sensor 12 is installed at a position sufficiently away from the heater 11 so that the output (measured value of the tube wall temperature) does not change even when the flow rate of the fluid changes.

  The temperature sensor 13 measures the temperature T2 of the pipe wall portion (measurement point 15d) of the pipe 15 heated by the heater 11. In this case, the change in the heat transfer coefficient of the fluid (the heat transfer coefficient between the tube wall / fluid) that changes with the change in the fluid flow rate is greatly reflected in the tube wall temperature T2 measured by the temperature sensor 13, that is, It is desirable to install the temperature sensor 13 immediately inside the heater 11 as shown in the figure (directly above or directly below) so that the heat flux passing through the measurement point 15d of the temperature sensor 13 becomes large.

  The tube wall temperature T1 (or fluid temperature) measured by the temperature sensor 12 and the tube wall temperature T2 measured by the temperature sensor 13 are input to an arithmetic device (not shown). In the arithmetic unit, as described in the background art section, based on the tube wall temperature T1 (or fluid temperature), the tube wall temperature T2 of the heater heating unit, the heating amount of the heater 11, the fluid properties, and the tube diameter. The flow velocity (flow rate) of the fluid is obtained by calculation.

  And the coil 14 is arrange | positioned inside the part heated with the heater 11 of the piping 15. As shown in FIG. The coil 14 is fixed to the inner peripheral surface 15b of the pipe 15 by appropriate fixing means such as adhesion. The direction of the central axis of the coil 14 is along the fluid flow direction (arrow A direction). In the illustrated example, a wire coil formed by forming a metal wire such as a wire in a spiral shape is used as the coil 14, but the present invention is not limited to this, and the coil 14 is formed (has a spiral shape). As the material of the linear body, an appropriate material such as a resin can be used.

  Since the coil 14 is provided in the pipe 15, the flow of the fluid can be controlled even when the fluid flowing in the pipe 15 is in a low flow rate region (low Reynolds region) where a laminar flow occurs unless the coil 14 is provided. The fluid can be brought into a turbulent state by turbulence by 14 (perturbing the boundary layer flow near the tube wall). That is, by providing the coil 14, the flow state can be made turbulent from a relatively low flow rate region (low Reynolds region). Therefore, a predetermined (desired) flow rate measurement range, that is, a relatively wide flow rate measurement range in which the flow state shifts from a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases unless the coil 14 is provided. The fluid can be in a turbulent state over the entire range. Therefore, linearity can be given to the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range.

  Moreover, it may replace with the coil 14 and you may make it use the turbulence promoter of another structure as shown in FIGS. 2 to 5 are only different in structure from the turbulence promoting body, and the other configurations are the same as those in FIG. 1, and therefore, the same reference numerals are given and the detailed description thereof is omitted.

  In the thermal flow meter shown in FIG. 2, a plurality of circular rings 21 as turbulence promoting bodies are provided inside a portion of the pipe 15 that is heated by the heater 11. The plurality of annular rings 21 are arranged at regular intervals in the flow direction of the fluid flowing in the pipe 15 (arrow A direction), and are fixed to the inner surface 15b of the pipe 15 by appropriate fixing means such as adhesion. By providing a plurality of annular rings 21 in the pipe 15 in this way, even when the fluid flowing in the pipe 15 is in a low flow rate region (low Reynolds area) where a laminar flow occurs if the annular ring 21 is not provided. The fluid flow can be made turbulent by disturbing the flow of the fluid by the annular ring 21 (disturbing the boundary layer flow near the tube wall). That is, by providing the ring 21, the flow state can be made turbulent from a relatively low flow rate region (low Reynolds region). For this reason, a predetermined (desired) flow rate measurement range, that is, a relatively wide flow rate measurement range in which the flow state shifts from a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases unless an annular ring 21 is provided. The fluid can be in a turbulent state in the entire range. Therefore, linearity can be given to the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range.

  In the thermal flow meter shown in FIG. 3, a protrusion 31 as a turbulence promoting body is provided inside a portion of the pipe 15 that is heated by the heater 11. The protrusion 31 protrudes from the inner surface of the pipe 15 and is an integral one formed in a spiral shape. In addition, the cross-sectional shape of the protrusion 31 can be set to an appropriate shape such as a triangular shape or a rectangular shape in addition to the trapezoidal shape shown in the illustrated example. By providing the protrusion 31 in the pipe 15 as described above, the fluid flowing in the pipe 15 is a laminar flow if the protrusion 31 is not provided, even in a low flow rate region (low Reynolds region). By disturbing the flow of the fluid by the protrusions 31 (disturbing the boundary layer flow near the tube wall), the fluid can be in a turbulent state. That is, by providing the protrusions 31, the flow can be made turbulent from the relatively low flow rate range (low Reynolds range). For this reason, a predetermined (desired) flow rate measurement range, that is, a relatively wide flow rate measurement range in which the flow state shifts to a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases unless the protrusion 31 is provided. The fluid can be in a turbulent state in the entire range. Therefore, linearity can be given to the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range.

  In the thermal flow meter shown in FIG. 4, a protrusion 41 as a turbulent flow promoting body is provided inside a portion heated by the heater 11 of the pipe 15. A plurality of protrusions 41 are provided on the inner surface of the pipe 15. In addition, the cross-sectional shape of the protrusion 31 can be set to an appropriate shape such as a truncated cone shape or a needle shape in addition to the conical shape as shown in the illustrated example. By providing the protrusion 41 in the pipe 15 as described above, the fluid flowing in the pipe 15 is in a low flow rate region (low Reynolds area) where a laminar flow occurs unless the protrusion 41 is provided. By disturbing the flow of the fluid by the protrusions 41 (disturbing the boundary layer flow near the tube wall), the fluid can be in a turbulent state. That is, by providing the protrusions 41, the flow state can be made turbulent from a relatively low flow rate range (low Reynolds range). For this reason, a predetermined (desired) flow rate measurement range, that is, a wide flow rate measurement range in which the flow state transitions to a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases unless the protrusion 41 is provided. The fluid can be turbulent in the range. Therefore, linearity can be given to the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range.

  In the thermal flow meter shown in FIG. 5, a twisted tape 51 as a turbulent flow promoting body is provided inside a portion heated by the heater 11 of the pipe 15. The twisted tape 51 is fixed to the inner peripheral surface 15b of the pipe 15 by appropriate fixing means such as adhesion. The twisted tape 51 has a structure in which a plate made of an appropriate material such as a metal plate is twisted, and the direction of the central axis is along the flow direction of the fluid (the direction of arrow A). Since the twisted tape 51 is provided in the pipe 15 as described above, the fluid flowing in the pipe 15 is in a low flow rate region (low Reynolds region) where a laminar flow is generated unless the twisted tape 51 is provided. The fluid flow can be made turbulent by disturbing the flow of the fluid by the twisted tape 51 (by turning the main flow to exchange the main flow and the flow in the vicinity of the pipe wall). That is, by providing the twisted tape 51, the flow state can be made turbulent from the relatively low flow rate region (low Reynolds region). Therefore, a predetermined (desired) flow measurement range, that is, a wide flow measurement range in which the flow state shifts to a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases unless the twisted tape 51 is provided. The fluid can be turbulent in the range. Therefore, linearity can be given to the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range.

As described above, according to the thermal flow meter of the present embodiment, the turbulence promoting body such as the coil 14, the ring 21, the protrusions 31 and 41, or the twisted tape 51 is heated by the heater 11 of the pipe 15. The turbulence promoter is used to disturb the flow of the fluid flowing through the pipe 15 so that the fluid is in a turbulent state over the predetermined flow rate measurement range of the fluid. Therefore, if a turbulence promoter is not provided, a relatively wide flow rate that causes the flow state to shift to a laminar flow region, a transition region, or a turbulent flow region if a turbulence promoter is not provided. The fluid can be in a turbulent state over the entire measurement range, and linearity is achieved in the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow measurement range. Fluid flow rate and heat transfer coefficient That is the relationship between the thermal type the output of the flow meter) is unique. For this reason, the flow rate measurement range is wide and accurate flow rate measurement is possible.
As the turbulent flow promoter, the use of the coil 14 is most preferable because it is inexpensive because of its ease of installation and availability.

<Embodiment 2>
If the pipe diameter is reduced, the fluid can be in a turbulent state even in a low flow rate region. However, when the pipe diameter is simply reduced, the flow rate of the fluid becomes very large and the heat transfer coefficient of the fluid becomes very large when measuring a high flow rate in the small pipe diameter pipe. In this case, the difference between the tube wall temperature T2 and the fluid temperature (tube wall temperature T1) becomes small, and the measurement accuracy decreases. For this reason, in order to increase the measurement accuracy, the difference between the tube wall temperature T2 and the fluid temperature (tube wall temperature T1) must be increased. To this end, the heater heating amount must be increased, which increases the cost. I will invite you.

  Therefore, in the second embodiment, the turbulent flow is promoted by reducing the tube diameter, and the above-mentioned problems occurring in that case are also solved. FIG. 6 shows a configuration diagram of a thermal type flow meter (boundary layer flow meter) according to Embodiment 2 of the present invention.

  The thermal flow meter shown in FIG. 6 includes heaters 61, 62, and 63 as heating means, a temperature sensor 64 such as a resistance temperature detector or a thermocouple as first temperature measuring means, and second temperature measuring means. 6 and a temperature sensor 65, 66, 67 such as a thermocouple, and the structure of the pipe 68 is devised (details will be described later), and is indicated by an arrow A in FIG. Thus, the flow rate (flow rate) of fluid such as water flowing in the pipe 68 is measured.

  The pipe 68 has a three-stage structure having three pipe parts 68A, 68B, 68C having different pipe diameters. The pipe portions 68A, 68B, 68C have smaller pipe diameters (inner diameters) in order from the upstream side in the fluid flow direction to the downstream side (hereinafter simply referred to as the upstream side and the downstream side). In the pipe portion 68C having the smallest pipe diameter located on the most downstream side, even a fluid in a low flow rate region that becomes laminar flow in the other pipe portions 68B and 68C becomes turbulent. In other words, the pipe diameter of the pipe portion 68C is set to such a value that the fluid is in a turbulent state even when the fluid flow rate is a predetermined low flow rate. As the fluid flow rate increases, the fluid is also turbulent in the pipe portion 68B, and the turbulent state is also in the pipe portion 68A.

  For this reason, in a predetermined (desired) flow rate measurement range, that is, only in a pipe part having a relatively large pipe diameter such as the pipe part 68A or the pipe part 68B, the flow state is increased as the fluid flow rate increases. The fluid can be in a turbulent state in the entire range of a relatively wide flow rate measurement range that shifts. Therefore, linearity can be given to the relationship between the fluid flow rate and the heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range. Note that the number of stages (the number of pipe portions having different pipe diameters) is not necessarily limited to three (three), and may be two (two) or four (four) or more as required. Good.

  The heaters 61, 62, and 63 are mounted on the outer peripheral surfaces 68A-1, 68B-1, and 68C-1 of the plurality of pipe portions 68A, 68B, and 68C having different pipe diameters, and the pipe portions 68A, 68B, and 68C-1, respectively. Each 68C tube wall is heated. The heaters 61, 62, and 63 are electric heaters and are connected to a heater power source (not shown). Accordingly, the heaters 61, 62, 63 generate heat by the power supplied from the heater power source and heat the pipe portions 68A, 68B, 68C, respectively. In addition, the heating amount of each heater 61, 62, 63 can be calculated | required suitably, for example by measuring the electric energy supplied to each heater 61, 62, 63 from a heater power supply with a wattmeter.

  The temperature sensor 64 is installed on the pipe wall of the pipe part 68A upstream of the installation position of the heater 61 arranged in the pipe part 68A located on the most upstream side of the pipe parts 68A, 68B, 68C having different pipe diameters. The temperature T1 of the tube wall portion (measurement point 68a) is measured. In this case, it is conceivable to directly measure the temperature of the fluid by the temperature sensor 64, but for this purpose, the temperature sensor 64 must be inserted into the pipe 68 (pipe portion 68A), and the temperature sensor 64 flows into the fluid. Therefore, it is preferable to measure the tube wall temperature T1 by the temperature sensor 64. Since the temperature sensor 64 is disposed at a position sufficiently away from the heater 61, the tube wall temperature T1 measured by the temperature sensor 64 is less affected by the heater 61 and is substantially equal to the temperature of the fluid flowing in the pipe 68. In other words, the temperature sensor 64 is installed at a position sufficiently away from the heater 61 so that the output (measured value of the tube wall temperature) does not change even when the flow rate of the fluid changes. In this case, of course, the temperature sensor 64 is sufficiently separated from the heaters 62 and 63.

  The temperature sensors 65, 66, and 67 are disposed in the pipe portions 68A, 68B, and 68C having different pipe diameters, and the pipe wall portions (measurements) of the pipe portions 68A, 68B, and 68C heated by the heaters 61, 62, and 63, respectively. Temperatures T2-1, T2-2, and T2-3 at points 68b, 68c, and 68d) are measured. Of course, these pipe heating and temperature measurement are not performed at the same time. When the pipe wall temperature T2-1 is measured by the temperature sensor 65, the pipe portion 61A is heated by the heater 61, and the pipe wall temperature T2-2 by the temperature sensor 66. When measuring the pipe portion 61B by the heater 62, and when measuring the pipe wall temperature T2-3 by the temperature sensor 67, the heater 63 heats the pipe portion 61A. In this case, the change in the heat transfer coefficient of the fluid (the heat transfer coefficient between the pipe wall / fluid) that changes with the change in the fluid flow rate is measured by the temperature sensors 65, 66, and 67. The temperature sensors 65, 66, and 67 are reflected in T2-2 and T2-3 so that the heat flux passing through the measurement points 68b, 68c, and 68d of the temperature sensors 65, 66, and 67 is increased. It is desirable that the heaters 61, 62, and 63 as shown in FIG.

  The tube wall temperature T1 (or fluid temperature) measured by the temperature sensor 64 and the tube wall temperatures T2-1, T2-2, and T2-3 measured by the temperature sensors 65, 66, and 67 are input to an arithmetic unit (not shown). In the arithmetic unit, as described in the background section, the tube wall temperature T1 (or fluid temperature), the tube wall temperature T2-1, T2-2, or T2-3 of the heater heating unit, and the heaters 61, 62, or 63 The flow velocity (flow rate) of the fluid is obtained by calculation based on the heating amount, the physical properties of the fluid, and the pipe diameter of the pipe portion 68A, 68B or 68C of each stage.

  As described above, according to the thermal flow meter of the present embodiment, the pipe 68 has a plurality of pipe portions 68A, 68B, 68C having different pipe diameters, thereby flowing in the pipe 68. The fluid is brought into a turbulent state over the entire range of the predetermined flow rate measurement range of the fluid, the heaters 61, 62, 63 are arranged in the pipe portions 68A, 68B, 68C having different pipe diameters, and the temperature sensor 64 is connected to the pipe. It arrange | positions upstream from the heater 61 arrange | positioned in the piping part 68A located in the most upstream among the some piping parts 68A, 68B, 68C from which a diameter differs, and temperature sensor 65, 66, 67 differs in a pipe diameter. Since the plurality of pipe portions 68A, 68B, and 68C are arranged respectively, the predetermined flow rate measurement range, that is, only a pipe portion having a relatively large pipe diameter increases the fluid flow rate. The fluid can be in a turbulent flow state over a relatively wide flow measurement range where the state moves from a laminar flow region, a transition region, and a turbulent flow region, and the fluid flow rate over the entire range of the predetermined flow measurement range. And the heat transfer coefficient (the heat transfer coefficient between the tube wall / fluid) can be made linear, so the relationship between the fluid flow rate and the heat transfer coefficient (ie, the output of the thermal flow meter) is unique. Become. Moreover, even when the fluid flow rate increases, the heater heating amount does not need to be increased, and the pipe wall temperature T2-1 or T2-2 measured by the temperature sensor 65 or 66 is used in the pipe portion 68A or 68B having a large pipe diameter. The difference from the fluid temperature or the tube wall temperature T1 measured by the temperature sensor 64 increases. For this reason, the flow rate measurement range is wide and the flow rate can be accurately measured without increasing the cost.

<Embodiment 3>
FIG. 7 is a configuration diagram of a thermal type flow meter (boundary layer flow meter) according to Embodiment 3 of the present invention. The thermal flow meter shown in FIG. 7 includes a heater 71 as a heating means, a temperature sensor 72 such as a resistance temperature detector or a thermocouple as a first temperature measurement means, and a temperature measurement as a second temperature measurement means. It has a temperature sensor 73 such as a resistor or a thermocouple, and measures the flow velocity (flow rate) of a fluid such as water flowing in the pipe 74 as indicated by an arrow A in FIG.

  The heater 71 is mounted on the outer peripheral surface of the pipe 74 and heats the pipe 74 (pipe wall). The heater 71 is an electric heater and is connected to a heater power source (not shown). Accordingly, the heater 71 generates heat by the power supplied from the heater power source and heats the pipe 74. The heating amount of the heater 71 can be determined as appropriate by, for example, measuring the amount of power supplied from the heater power source to the heater 71 with a wattmeter.

  The temperature sensor 72 is installed on the pipe wall of the pipe 74 on the upstream side (hereinafter simply referred to as the upstream side) in the fluid flow direction from the installation position of the heater 71, and the temperature T1 of the pipe wall part (measurement point 74a) is measured. taking measurement. In this case, the temperature of the fluid may be directly measured by the temperature sensor 72. To this end, the temperature sensor 72 must be inserted into the pipe 74, and the temperature sensor 72 becomes a resistance against the fluid flow. Therefore, it is desirable to measure the tube wall temperature T1 by the temperature sensor 72. Since the temperature sensor 72 is disposed at a position sufficiently away from the heater 71, the tube wall temperature T1 measured by the temperature sensor 72 is less affected by the heater 71 and is substantially equal to the temperature of the fluid flowing in the pipe 74. In other words, the temperature sensor 72 is installed at a position sufficiently away from the heater 71 so that the output (measured value of the tube wall temperature) does not change even if the flow rate of the fluid changes.

  The temperature sensor 73 measures the temperature T2 of the pipe wall portion (measurement point 74b) of the pipe 74 heated by the heater 71. In this case, the change in the heat transfer coefficient of the fluid (the heat transfer coefficient between the tube wall / fluid) that changes with the change in the fluid flow rate is greatly reflected in the tube wall temperature T2 measured by the temperature sensor 73, that is, It is desirable that the temperature sensor 73 is installed immediately inside the heater 71 as shown in the figure so that the heat flux passing through the measurement point 74b of the temperature sensor 73 is increased.

  The tube wall temperature T1 (or fluid temperature) measured by the temperature sensor 72 and the tube wall temperature T2 measured by the temperature sensor 73 are input to an arithmetic device (not shown). In the arithmetic unit, as described in the background section, the tube wall temperature T1 (or fluid temperature), the tube wall temperature T2 of the heater heating unit, the heating amount of the heater 71, the fluid properties, and the piping (spiral tube) 74 The flow velocity (flow rate) of the fluid is obtained by calculation based on the pipe diameter.

  The pipe 74 is a spiral pipe. For this reason, the fluid flowing in the spiral tube is disturbed (a swirl flow), and the flow state becomes a turbulent state from a relatively low flow rate region. Therefore, a predetermined (desired) flow rate measurement range of the fluid, that is, a relatively wide range in which the flow state shifts to a laminar flow region, a transition region, and a turbulent flow region as the fluid flow rate increases unless the pipe 74 is a spiral tube. Since the fluid can be in a turbulent state in the entire flow rate measurement range, the linearity of the relationship between the fluid flow rate and the heat transfer rate (heat transfer rate between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range. Can be given. In this case, the pipe 74 may be at least a pipe part (temperature measurement part of the temperature sensor 73) heated by the heater 71, and other pipe parts (temperature measurement part of the temperature sensor 72, etc.) are not necessarily used. Since it is not necessary to make a turbulent flow, it is not necessary to use a spiral tube (for example, a straight tube).

  As described above, according to the thermal type flow meter of the present embodiment, at least the pipe portion heated by the heater 71 of the pipe 74 is a spiral pipe, thereby disturbing the flow of the fluid flowing in the spiral pipe. Since the fluid is in a turbulent state in the entire range of the predetermined flow rate measurement range of the fluid, the fluid flow rate is increased unless the predetermined flow rate measurement range of the fluid, that is, the pipe 74 is a spiral tube. In addition, since the fluid can be in a turbulent flow state in a relatively wide flow measurement range where the flow state shifts to a laminar flow region, a transition region, and a turbulent flow region, The relationship between fluid flow rate and heat transfer coefficient (tube wall / fluid heat transfer coefficient) can be linearized, and the relationship between fluid flow rate and heat transfer coefficient (ie thermal flow meter output) is unique It becomes. For this reason, the flow rate measurement range is wide and accurate flow rate measurement is possible.

<Embodiment 4>
FIG. 8 is a configuration diagram of a thermal flow meter (boundary layer flow meter) according to Embodiment 4 of the present invention. The thermal flow meter shown in FIG. 8 includes a heater 81 as a heating means, a temperature sensor 82 such as a resistance temperature detector or a thermocouple as a first temperature measurement means, and a temperature measurement as a second temperature measurement means. It has a temperature sensor 83 such as a resistor or a thermocouple, and measures the flow velocity (flow rate) of a fluid such as water flowing in the pipe 84 as shown by an arrow A in FIG.

  The heater 81 is mounted on the outer peripheral surface 84c of the pipe 84 and heats the pipe 84 (pipe wall). The heater 81 is an electric heater and is connected to a heater power source (not shown). Therefore, the heater 81 generates heat by the power supplied from the heater power source and heats the pipe 84. The heating amount of the heater 81 can be determined as appropriate by, for example, measuring the amount of power supplied from the heater power source to the heater 81 with a wattmeter.

  The temperature sensor 82 is installed on the pipe wall of the pipe 84 on the upstream side (hereinafter simply referred to as the upstream side) in the fluid flow direction from the installation position of the heater 81, and the temperature T1 of the pipe wall portion (measurement point 84a) is measured. taking measurement. In this case, it is conceivable to directly measure the temperature of the fluid by the temperature sensor 82, but for this purpose, the temperature sensor 82 must be inserted into the pipe 84, and the temperature sensor 82 becomes a resistance against the flow of the fluid. Therefore, it is desirable to measure the tube wall temperature T1 by the temperature sensor 82. Since the temperature sensor 82 is disposed at a position sufficiently away from the heater 81, the tube wall temperature T1 measured by the temperature sensor 82 is less affected by the heater 81 and is substantially equal to the temperature of the fluid flowing in the pipe 84. In other words, the temperature sensor 82 is installed at a position sufficiently away from the heater 81 so that the output (measured value of the tube wall temperature) does not change even if the flow rate of the fluid changes.

  The temperature sensor 83 measures the temperature T2 of the pipe wall portion (measurement point 84b) of the pipe 84 heated by the heater 81. In this case, the change in the heat transfer coefficient of the fluid (the heat transfer coefficient between the tube wall / fluid) that changes with the change in the fluid flow rate is greatly reflected in the tube wall temperature T2 measured by the temperature sensor 83, that is, It is desirable that the temperature sensor 83 is installed immediately inside the heater 81 as shown in the drawing so that the heat flux passing through the measurement point 84b of the temperature sensor 83 is increased.

  The tube wall temperature T1 (or fluid temperature) measured by the temperature sensor 82 and the tube wall temperature T2 measured by the temperature sensor 83 are input to an arithmetic device (not shown). In the arithmetic unit, as described in the background section, the tube wall temperature T1 (or fluid temperature), the tube wall temperature T2 of the heater heating unit, the heating amount of the heater 81, the fluid properties, and the diameter of the bend tube 84A. Based on the above, the flow velocity (flow rate) of the fluid is obtained by calculation.

  A pipe portion heated by the heater 81 of the pipe 84 is a bend pipe 84A. That is, the heater 81 is provided on the outer peripheral surface of the bend pipe 84, and the temperature sensor 83 measures the tube wall temperature of the bend pipe 84. Since the fluid flowing in the pipe 84 as shown by the arrow A collides with the inner peripheral surface 84A-1 of the bend pipe 84A in which the heater 81 and the temperature sensor 83 are installed, the flow is disturbed. From time to time, the flow conditions become turbulent. For this reason, unless the bend pipe 84A is used as the predetermined (desired) flow rate measurement range of the fluid, that is, if the heater heating portion of the pipe 84 is not the bend pipe 84A, the flow state shifts to a laminar flow area, a transition area, and a turbulent flow area. The fluid can be in a turbulent state over the entire range of the relatively wide flow rate measurement range, and the fluid flow rate and heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range. Linearity can be given to the relationship.

  As described above, according to the thermal type flow meter of the present embodiment, the pipe portion heated by the heater 81 of the pipe 84 is a bend pipe, thereby disturbing the flow of the fluid flowing in the bend pipe. Since the fluid is in a turbulent state in the entire range of the predetermined flow rate measurement range of the fluid, the predetermined flow rate measurement range of the fluid, that is, the heater heating portion of the pipe 84 must be the bend pipe 84A. As the fluid flow rate increases, the fluid can be in a turbulent flow state over a relatively wide flow rate measurement range in which the flow state shifts to a laminar flow region, a transition region, and a turbulent flow region. Since the relationship between the fluid flow rate and the heat transfer coefficient (tube wall / fluid heat transfer coefficient) can be linearized over the entire range, the fluid flow rate and the heat transfer coefficient (ie, the output of the thermal flow meter) The relationship is unique. For this reason, the flow rate measurement range is wide and accurate flow rate measurement is possible.

<Embodiment 5>
FIG. 9 is a configuration diagram of a thermal type flow meter (boundary layer flow meter) according to Embodiment 5 of the present invention. The thermal flow meter shown in FIG. 9 includes a heater 91 as a heating means, a temperature sensor 92 such as a resistance temperature detector or a thermocouple as a first temperature measurement means, and a temperature measurement as a second temperature measurement means. It has a temperature sensor 93 such as a resistor or a thermocouple, and measures the flow velocity (flow rate) of a fluid such as water flowing in the pipe 94 as indicated by an arrow A in FIG.

  A plate-like fluid collision member 95 is disposed in the pipe 94. The fluid collision member 95 is fixed to the inner peripheral surface 94b of the pipe 94 via a support member (not shown). Therefore, the fluid flowing in the pipe 94 as shown by the arrow A collides with one side surface (collision surface) 95a of the fluid collision member 95 and the flow is disturbed. It becomes a turbulent state. For this reason, unless the fluid collision member 95 is disposed in the predetermined (desired) flow rate measurement range of the fluid, that is, the fluid flow rate increases, the flow state shifts to the laminar flow region, the transition region, and the turbulent flow region. The fluid can be in a turbulent state over the entire range of the relatively wide flow rate measurement range, and the fluid flow rate and heat transfer coefficient (heat transfer coefficient between the tube wall / fluid) over the entire range of the predetermined flow rate measurement range Linearity can be given to the relationship.

  The heater 91 is mounted on the other side surface 95 c of the fluid collision member 95 and heats the fluid collision member 95. The heater 91 is an electric heater and is connected to a heater power source (not shown). Accordingly, the heater 91 generates heat by the power supplied from the heater power source and heats the fluid collision member 95. The heating amount of the heater 91 can be determined as appropriate by, for example, measuring the amount of power supplied from the heater power source to the heater 91 with a wattmeter.

  The temperature sensor 92 is installed on the pipe wall of the pipe 94 on the upstream side (hereinafter simply referred to as the upstream side) in the fluid flow direction from the installation position of the heater 91, and the temperature T1 of the pipe wall portion (measurement point 94a) is measured. taking measurement. In this case, it is conceivable to directly measure the temperature of the fluid by the temperature sensor 92. To this end, the temperature sensor 92 must be inserted into the pipe 94, and the temperature sensor 92 becomes a resistance against the flow of the fluid. Therefore, it is desirable to measure the tube wall temperature T1 by the temperature sensor 92. Since the temperature sensor 92 is disposed at a position sufficiently away from the heater 91, the tube wall temperature T1 measured by the temperature sensor 92 is less affected by the heater 91 and is substantially equal to the temperature of the fluid flowing in the pipe 94. In other words, the temperature sensor 92 is installed at a position sufficiently away from the heater 91 so that the output (measured value of the tube wall temperature) does not change even if the flow rate of the fluid changes.

  The temperature sensor 93 is attached to the fluid collision member 95, and measures the temperature T2 of the fluid collision member 95 heated by the heater 91. In this case, the change in the heat transfer coefficient of the fluid (the heat transfer coefficient between the tube wall / fluid) that changes with the change in the fluid flow rate is greatly reflected in the tube wall temperature T2 measured by the temperature sensor 93, that is, It is desirable that the temperature sensor 93 is installed immediately inside the heater 91 as shown in the figure so that the heat flux passing through the measurement point 95b of the temperature sensor 93 is increased.

  The tube wall temperature T1 (or fluid temperature) measured by the temperature sensor 92 and the tube wall temperature T2 measured by the temperature sensor 93 are input to an arithmetic device (not shown). In the arithmetic unit, as described in the background section, the tube wall temperature T1 (or fluid temperature), the tube wall temperature T2 of the heater heating unit, the heating amount of the heater 91, the fluid properties, the tube diameter of the pipe 94, Based on the above, the flow velocity (flow rate) of the fluid is calculated.

  As described above, according to the thermal type flow meter of the present embodiment, the fluid flowing in the pipe 94 collides with the fluid flowing through the pipe 94 in the entire range of the predetermined flow rate measurement range of the fluid. Since it has a fluid collision member 95 that brings the fluid into a turbulent state, the flow rate is increased as the fluid flow rate increases unless the fluid collision member is arranged in a predetermined flow rate measurement range of the fluid, that is, in the pipe. The fluid can be in a turbulent flow state over a relatively wide flow rate measurement range such as a transition from a laminar flow region, a transition region, and a turbulent flow region. Since the relationship between the transfer rate (heat transfer rate between the tube wall / fluid) can be made linear, the relationship between the fluid flow rate and the heat transfer rate (ie, the output of the thermal flow meter) is unique. For this reason, the flow rate measurement range is wide and accurate flow rate measurement is possible.

  The present invention relates to a thermal flow meter (boundary layer flow meter), and is useful when applied to flow measurement in a relatively wide flow measurement range in various places such as a space station.

It is a block diagram of the thermal type flow meter (boundary layer flow meter) based on Embodiment 1 of this invention. It is a block diagram of the thermal type flow meter (boundary layer flow meter) based on Embodiment 1 of this invention. It is a block diagram of the thermal type flow meter (boundary layer flow meter) based on Embodiment 1 of this invention. It is a block diagram of the thermal type flow meter (boundary layer flow meter) based on Embodiment 1 of this invention. It is a block diagram of the thermal type flow meter (boundary layer flow meter) based on Embodiment 1 of this invention. It is a block diagram of the thermal type flow meter (boundary layer flow meter) based on Embodiment 2 of this invention. It is a block diagram of the thermal type flow meter (boundary layer flow meter) based on Embodiment 3 of this invention. It is a block diagram of the thermal type flow meter (boundary layer flow meter) concerning Embodiment 4 of this invention. It is a block diagram of the thermal type flow meter (boundary layer flow meter) which concerns on Example 5 of this invention. It is a block diagram of the conventional thermal type flow meter (boundary layer flow meter). It is a graph which shows the relationship between a fluid flow rate (flow condition) and a heat transfer rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Heater 12, 13 Temperature sensor 14 Coil 15 Piping 15a Outer peripheral surface 15b Inner peripheral surface 15c, 15d Measurement point 21 Ring 31 Projection 41 Projection 51 Twist tape 61, 62, 63 Heater 64, 65, 66, 67 Temperature sensor 68 Piping 68A, 68B, 68C Piping portion 68a, 68b, 68c, 68d Measuring point 68A-1, 68B-1, 68C-1 Outer peripheral surface 71 Heater 72, 73 Temperature sensor 74 Piping (spiral tube)
74a, 74b Measurement point 81 Heater 82, 83 Temperature sensor 84 Piping 84A Bend pipe 84a, 84b Measurement point 84c Outer peripheral surface 84A-1 Inner peripheral surface

Claims (9)

Heating means for heating the piping;
First temperature measuring means for measuring the temperature of the pipe wall portion of the pipe or the temperature of the fluid flowing in the pipe at a position upstream of the heating means;
A thermal flow meter having a second temperature measuring means for measuring a temperature of a pipe wall portion of the pipe heated by the heating means,
A turbulence promoting body is provided inside the portion of the pipe heated by the heating means, and the turbulent flow promoting body disturbs the flow of the fluid flowing through the pipe so that the entire range of the predetermined flow rate measurement range of the fluid is reached. A thermal flow meter characterized in that the fluid is in a turbulent state. The thermal flow meter according to claim 1,
The thermal flow meter, wherein the turbulence promoting body is a coil. The thermal flow meter according to claim 1,
The thermal flow meter according to claim 1, wherein the turbulent flow promoting body is a plurality of circular rings arranged at intervals in the fluid flow direction. The thermal flow meter according to claim 1,
The thermal flow meter, wherein the turbulent flow promoting body is a protrusion projecting from the inner surface of the pipe. The thermal flow meter according to claim 1,
The thermal flow meter, wherein the turbulence promoting body is a twisted tape. Heating means for heating the piping;
First temperature measuring means for measuring the temperature of the pipe wall portion of the pipe or the temperature of the fluid flowing in the pipe at a position upstream of the heating means;
A thermal flow meter having a second temperature measuring means for measuring a temperature of a pipe wall portion of the pipe heated by the heating means,
The pipe has a multi-stage structure having a plurality of pipe parts with different pipe diameters, thereby making the fluid turbulent in the entire range of a predetermined flow rate measurement range of the fluid flowing in the pipe,
The heating means is disposed in each of a plurality of pipe portions having different pipe diameters,
The first temperature measuring means is arranged on the upstream side of the heating means arranged on the pipe part located on the most upstream side among the plurality of pipe parts having different pipe diameters,
The thermal flow meter, wherein the second temperature measuring means is disposed in each of a plurality of pipe portions having different pipe diameters. Heating means for heating the piping;
First temperature measuring means for measuring the temperature of the pipe wall portion of the pipe or the temperature of the fluid flowing in the pipe at a position upstream of the heating means;
A thermal flow meter having a second temperature measuring means for measuring a temperature of a pipe wall portion of the pipe heated by the heating means,
The pipe portion heated by at least the heating means of the pipe is a spiral pipe, thereby disturbing the flow of the fluid flowing in the spiral pipe and turbulently flowing the fluid in the entire range of the predetermined flow rate measurement range of the fluid. A thermal flow meter characterized by being in a state. Heating means for heating the piping;
First temperature measuring means for measuring the temperature of the pipe wall portion of the pipe or the temperature of the fluid flowing in the pipe at a position upstream of the heating means;
A thermal flow meter having a second temperature measuring means for measuring a temperature of a pipe wall portion of the pipe heated by the heating means,
By making a pipe part heated by the heating means of the pipe into a bend pipe, the flow of the fluid flowing in the bend pipe is disturbed, and the fluid is in a turbulent state in the entire range of a predetermined flow rate measurement range of the fluid. A thermal flow meter characterized by: A fluid collision member that is arranged in a pipe and causes the fluid to flow in a turbulent state in the entire range of a predetermined flow rate measurement range of the fluid by collision of the fluid flowing in the pipe; and
Heating means for heating the fluid collision member;
First temperature measuring means for measuring the temperature of the pipe wall portion of the pipe or the temperature of the fluid flowing in the pipe at a position upstream of the heating means;
And a second temperature measuring means for measuring the temperature of the fluid collision member heated by the heating means.

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