JP4037221B2 - In-pipe flow measurement device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe flow rate measuring device for measuring a mass flow rate of a fluid to be measured flowing in a fluid pipe.
[0002]
[Prior art]
As a conventional in-pipe flow rate measuring device, there is known a Karman vortex flowmeter that detects a vortex train generated by a vortex generator placed in a flow of a fluid to be measured, that is, a Karman vortex and measures a flow rate. For example, Japanese Patent Laid-Open No. 4-66817 discloses a vortex generator, a communication hole provided in the vortex generator so as to be orthogonal to the traveling direction of the fluid to be measured, and a microflow provided in the middle of the communication hole. A Karman vortex flowmeter with a sensor is disclosed. For example, a microflow sensor is provided with a heater on a silicon substrate, and temperature sensors made of small metal thin films on both sides of the heater. This is a volumetric flowmeter that obtains the detection signal and measures the flow velocity of the fluid to be measured from this signal.
[0003]
However, when the volume flow rate is converted into the mass flow rate, the volume flow rate value cannot be calculated unless the volume flow rate value is corrected with temperature or pressure measurement data. For this reason, it is necessary to newly install a thermometer or a pressure gauge in the flow meter.
[0004]
[Problems to be solved by the invention]
However, since the conventional pipe flow rate measuring device has the above-described configuration, if a thermometer or pressure gauge necessary for detecting the mass flow rate is brought close to the vortex generator, the vortex generation is affected. Since an error occurs in the mass flow rate of the fluid to be measured, it is necessary to install it at a certain distance, and there is a problem that the installation space of the entire apparatus becomes large. In addition, since it is necessary to secure an installation space for the thermometer and the pressure gauge, there is a problem that the installation space for the entire apparatus becomes large in this respect as well. Furthermore, the above-described flow meter and pressure gauge require individual wiring and preparation for installation, and there is a problem that the overall cost including measurement work and the like increases.
[0005]
The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a small and inexpensive in-pipe flow rate measuring device capable of accurately detecting a mass flow rate.
[0006]
[Means for Solving the Problems]
An in-pipe flow measuring device according to the present invention includes a device main body having a vortex generating unit that is mounted on a fluid pipe so as to cross the radial direction of the fluid pipe and that generates a vortex in the fluid to be measured in the fluid pipe, and the device A bypass channel formed in a direction perpendicular to the traveling direction of the fluid to be measured in a vortex generating portion of the main body; a length direction of the bypass channel formed in the apparatus main body and a traveling direction of the fluid to be measured A hole communicating in the middle of the bypass flow path from a direction orthogonal to the insertion path, an insertion member inserted into the hole, and a thermal flow rate detection element disposed at the tip of the insertion member and facing the bypass flow path A fluid temperature detecting element for detecting the temperature of the fluid to be measured; a fixing member for fixing the insertion member to the hole of the apparatus main body; a pressure detecting element disposed on the fixing member; and communicating with the hole. The pressure of the fluid to be measured is the pressure Out is obtained by configured with said fixed pressure passage formed member so as to act on the device.
[0007]
The in-pipe flow rate measuring apparatus according to the present invention is configured such that a thermal flow rate detecting element, a fluid temperature detecting element, and a pressure detecting element are detachably arranged with respect to the apparatus main body.
[0008]
The in-pipe flow measuring device according to the present invention is configured such that the pressure detection element is disposed at a position away from the vortex generating portion in the pressure channel communicating with the bypass channel.
[0009]
The in-pipe flow rate measuring device according to the present invention is configured to weld and fix the attachment portion of the thermal flow rate detection element to the tip of the insertion member.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
Embodiment 1 FIG.
1 is a front view showing an external configuration of a pipe flow rate measuring apparatus according to Embodiment 1 of the present invention, FIG. 2 is a side view seen from the direction of arrow A in FIG. 1, and FIG. Fig. 4 is a sectional view taken along line III, Fig. 4 is an exploded sectional view showing the configuration of each part of the in-pipe flow rate measuring device shown in Fig. 3, Fig. 5 is a sectional view taken along line VV in Fig. 3, and Fig. 6 is a thermal diagram. It is a top view which shows the internal structure of a type | formula flow velocity detection element.
[0011]
In the figure, 1 is an in-pipe flow measuring device (hereinafter referred to as a mass flow meter). The mass flow meter 1 includes an apparatus main body 4 having a vortex generator 3 that generates a Karman vortex in a fluid to be measured (not shown) in a fluid pipe 2. As shown in FIGS. 2 and 3, the apparatus main body 4 is a columnar member that is longer than the diameter of the fluid pipe 2, and the radial direction from the through hole 2 a formed in the wall portion of the fluid pipe 2 into the fluid pipe 2. Has been inserted to cross. The fluid pipe 2 may have a configuration in which flanges (not shown) are mounted on both sides so that a predetermined section in which the apparatus main body 4 is disposed can be independently separated, and the apparatus main body 4 is directly incorporated in the fluid pipe 2. It is good also as a structure. Between the outer peripheral part of the apparatus main body 4 and the through hole 2a of the fluid pipe 2, an O-ring 5 that keeps the hermeticity of the fluid pipe 2 is disposed. Further, the apparatus main body 4 is fixed to the fluid pipe 2 by a fixing plate 6.
[0012]
A bypass channel 7 is formed in the vortex generator 3 of the apparatus main body 4 in a direction orthogonal to the traveling direction (arrow B direction) of the fluid to be measured (not shown), and both ends thereof are openings 8. ing. In the apparatus main body 4, the length of the bypass flow path 7 (in the direction of arrow C) and the measurement target are directed from the middle of the bypass flow path 7 toward the rear end portion (the upper end portion in FIGS. 3 and 4). A small-diameter hole (hole) 9 is formed in a direction (length direction of the apparatus main body 4) orthogonal to the traveling direction of the fluid (not shown) (arrow B direction). A pipe (insertion member) 10 having an outer diameter slightly smaller than the inner diameter of the small diameter hole 9 is detachably inserted into the small diameter hole 9 of the apparatus body 4.
[0013]
An attachment portion 13 of a can package 12 on which a microflow sensor (thermal flow rate detection element) 11 is mounted is fixed by welding to the tip portion 10a of the pipe 10. As shown in FIG. 6, the microflow sensor 11 is provided with one heater 11b on a silicon substrate 11a and temperature sensors 11c and 11d made of small metal thin films on both sides of the heater 11b. And 11d detect the temperature change on both sides of the heater 11b to obtain a fluid vibration detection signal. At this time, the detection circuit includes a circuit for supplying a predetermined power to the heater 11b of the microflow sensor 11 by a driving power source VH to heat it to a constant temperature, and a driving power source for the temperature sensors 11c and 11d on both sides of the heater 11b. A circuit for applying a constant voltage by VB is prepared and configured to have a function of detecting and amplifying the voltage V of the vibration waveform generated at the midpoint between the temperature sensors 11c and 11d. The detection voltage obtained by this detection circuit is input to an arithmetic circuit (not shown), calculated as the number of vibrations per unit time, and multiplied by the previously measured Strouhal number, It is possible to measure the flow rate. Such a microflow sensor 11 is disposed at a position facing the bypass flow path 7 as shown in FIG. 5 because the tip 10 a of the pipe 10 is inserted to the deepest part of the small-diameter hole 9. The pipe 10 inserted into the small diameter hole 9 of the apparatus main body 4 is formed behind the small diameter hole 9 of the apparatus main body 4 and is press-fitted into a large diameter hole 14 having an inner diameter larger than the small diameter hole 9 (fixing member). ) 15. A pressure sensor (pressure detection element) 16 is screwed into the upper opening 15a of the seal adapter 15, and the rear end portion 10b of the pipe 10 is fitted into the lower opening 15b. As shown in FIG. 6, an ambient temperature sensor (fluid temperature detecting element) 11e for detecting the temperature of a fluid to be measured (not shown) is provided on the silicon substrate 11a.
[0014]
A small clearance between the bypass channel 7 and the pressure sensor 16 is first passed from the bypass channel 7 to the small diameter hole 9 and the inner peripheral surface of the lower opening 15 b of the seal adapter 15 and the outer peripheral surface of the pipe 10. Thus, a pressure channel 17 penetrating the inside of the seal adapter 15 is formed. Therefore, between the outer peripheral surface of the pipe 10 and the seal adapter 15 and between the inner peripheral surface of the large-diameter hole 14 of the apparatus main body 4 and the outer peripheral surface of the seal adapter 15, O-rings 18 and 19 are provided for the purpose of securing the pressure channel 17. Further, the large-diameter hole 14 and the seal adapter 15 are held by a seal nut 20 screwed into the outer surface of the rear end portion (the upper end portion in FIGS. 3 and 4) of the apparatus body 4 and the outer surface of the seal adapter 15. Yes.
[0015]
On the outer peripheral surface of the seal adapter 15, a signal amplifying printed wiring board 21 for the microflow sensor 11 and the pressure sensor 16 is provided. The connection line 22 of the microflow sensor 11 is connected to the printed wiring board 21 through the internal space of the pipe 10. The space surrounding the printed wiring board 21 and the pressure sensor 16 is protected by a cylindrical case 24 attached to the outside of the rear end portion (upper end portion in FIGS. 3 and 4) of the apparatus body 4 via an O-ring 23. Yes. A case adapter 26 is attached to the inside of the upper end of the case 24 via an O-ring 25, and a housing 27 is attached to the case adapter 26. A terminal 28 is assembled inside the housing 27, and a printed wiring for calculating a mass flow rate of a fluid to be measured (not shown) based on measurement data from the microflow sensor 11 and the pressure sensor 16. A substrate 29 is provided. A cover 30 is screwed into the opening 27a of the housing 27, and a display 31 for displaying the mass flow rate of the fluid to be measured (not shown) is provided on the opposite side of the opening 27a. . In addition, 32 shown in FIG. 1 is a conduit connection part.
[0016]
Next, the operation will be described.
First, the fluid to be measured is detected by the flow velocity data and the ambient temperature sensor 11e of the microflow sensor 11 from the detection signal of the fluid vibration related to the fluid to be measured (not shown) by the microflow sensor 11 disposed at the position facing the bypass flow path 7. Temperature data for (not shown) is obtained. Furthermore, pressure data relating to a fluid to be measured (not shown) guided from the bypass channel 7 through the pressure channel 17 by the pressure sensor 16 is obtained. Since the pressure sensor 16 is provided in the pressure channel 17 away from the vortex generator 3, the static pressure does not affect the vortex generation of the fluid to be measured (not shown) and is not affected by the Karman vortex. It is possible to measure pressure. Next, the flow rate data of the fluid to be measured (not shown) is corrected with the temperature data and the pressure data, and is calculated by the CPU (not shown) to obtain the mass flow rate.
[0017]
When removing the pressure sensor 16 from the apparatus main body 4 for maintenance such as replacement work, the pressure sensor 16 can be detached from the seal adapter 15 after removing the housing 27 and the case 24 from the apparatus main body 4. is there. When the microflow sensor 11 is removed from the apparatus main body 4 for maintenance such as replacement work, first, the housing 27 and the case 24 are first removed from the apparatus main body 4, the seal nut 20 is removed, and the pressure sensor 16. By removing the seal adapter 15 from the apparatus main body 4, it is possible to remove the pipe 10 in which the microflow sensor 11 is disposed at the distal end portion 10 a.
[0018]
As described above, according to the first embodiment, the pressure sensor 16 is disposed on the seal adapter 15 that fixes the pipe 10 having the microflow sensor 11 at the distal end portion 10 a to the small-diameter hole 9 of the apparatus body 4. Since it is configured, the micro flow sensor 11 and the pressure sensor 16 can be integrated, the mass flow meter 1 can be miniaturized, and wiring work for each sensor is not required, so that the measurement work and the like are included. The overall cost can be reduced.
[0019]
According to the first embodiment, since the microflow sensor 11 including the ambient temperature sensor 11e and the pressure sensor 16 are detachably arranged with respect to the fluid pipe 2, each sensor is connected to the fluid pipe as necessary. 2 can be removed, and there is an effect that maintenance such as replacement work can be facilitated.
[0020]
According to the first embodiment, the pressure sensor 16 is arranged at a position away from the vortex generator 3 in the pressure channel 17 communicating with the bypass channel 7. The pressure of the measurement fluid can be measured by static pressure. Further, since the pressure sensor 16 does not affect the generation of the Karman vortex, there is an effect that the mass flow rate of the fluid to be measured can be accurately measured.
[0021]
According to the first embodiment, since the attachment portion 13 of the can package 12 for mounting the microflow sensor 11 is welded and fixed to the tip portion 10a of the pipe 10, the airtightness is maintained with respect to the fluid to be measured. It is possible to avoid the influence of corrosion and oxidation due to the fluid to be measured such as the connection line 22.
[0022]
【The invention's effect】
As described above, according to the present invention, an apparatus main body having a vortex generator that is attached to a fluid pipe so as to traverse in the radial direction of the fluid pipe and generates a vortex in the fluid to be measured in the fluid pipe; A bypass channel formed in a direction perpendicular to the direction of travel of the fluid to be measured in the vortex generating portion of the apparatus main body, and the length direction of the bypass channel and the progress of the fluid to be measured formed in the apparatus body A hole communicating in the middle of the bypass flow path from a direction orthogonal to the direction, an insertion member inserted into the hole, and a thermal flow rate detection element disposed at the tip of the insertion member and facing the bypass flow path A fluid temperature detecting element for detecting the temperature of the fluid to be measured, a fixing member for fixing the insertion member to the hole of the apparatus main body, a pressure detecting element disposed on the fixing member, and the hole The pressure of the fluid to be measured is communicated with the pressure sensor. Since the pressure flow path formed in the fixing member is provided so as to act on the element, the thermal flow rate detecting element, the fluid temperature detecting element and the pressure detecting element can be integrated, and the apparatus can be miniaturized. This eliminates the need for wiring work for each detection element, thereby reducing the overall cost including measurement work and the like.
[0023]
According to the present invention, since the thermal flow velocity detecting element, the fluid temperature detecting element, and the pressure detecting element are detachably arranged with respect to the fluid pipe, the detecting element can be removed from the fluid pipe as necessary. This is advantageous in that maintenance such as replacement work can be facilitated.
[0024]
According to the present invention, since the pressure detection element is arranged at a position away from the vortex generator in the pressure channel communicating with the bypass channel, the pressure of the fluid to be measured is statically reduced by the pressure detection element. It can be measured with pressure. Further, since the pressure detection element does not affect the generation of vortices, there is an effect that the mass flow rate of the fluid to be measured can be accurately measured.
[0025]
According to the present invention, since the attachment portion of the thermal flow velocity detection element is welded and fixed to the distal end of the insertion member, airtightness can be maintained with respect to the fluid to be measured, and corrosion due to the fluid to be measured such as a connection line. And the effect of avoiding the effects of oxidation.
[Brief description of the drawings]
FIG. 1 is a front view showing an external configuration of an in-pipe flow rate measuring apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a side view as seen from the direction of arrow A in FIG.
3 is a cross-sectional view taken along line III-III in FIG.
4 is an exploded cross-sectional view showing the configuration of each part of the in-pipe flow rate measuring apparatus shown in FIG. 3;
5 is a cross-sectional view taken along line VV in FIG.
FIG. 6 is a plan view showing an internal configuration of a thermal flow rate detection element.
[Explanation of symbols]
1 Mass flow meter (pipe flow measurement device)
2 Fluid pipe 2a Through hole 3 Vortex generator 4 Device body 5 O-ring 6 Fixing plate 7 Bypass flow path 8 Fine hole 9 Small diameter hole 10 Pipe (insertion member)
10a Front end portion 10b Rear end portion 11 Micro flow sensor (thermal flow rate detecting element)
11a Silicon substrate 11b Heater 11c, 11d Temperature sensor 11e Ambient temperature sensor (fluid temperature detection element)
12 Can package 13 Mounting portion 14 Large-diameter hole 15 Seal adapter (fixing member)
15a Upper opening 15b Lower opening 16 Pressure sensor (pressure detection element)
17 Pressure channel 18, 19 O-ring 20 Seal nut 21 Printed wiring board 22 for signal amplification Connection line 23 O-ring 24 Case 25 O-ring 26 Case adapter 27 Housing 28 Terminal 29 Printed wiring board 30 Cover 31 Display part 32 Conduit connection part

Claims (4)

An apparatus main body having a vortex generating portion attached to the fluid pipe so as to cross the radial direction of the fluid pipe and generating a vortex in the measured fluid within the fluid pipe, and the measured fluid in the vortex generating section of the apparatus main body A bypass channel formed in a direction perpendicular to the traveling direction of the bypass channel, and a bypass channel formed in the apparatus main body and from a direction perpendicular to the length direction of the bypass channel and the traveling direction of the fluid to be measured. A hole communicating in the middle, an insertion member inserted into the hole, a thermal flow rate detecting element disposed at the tip of the insertion member and facing the bypass flow path, and detecting the temperature of the fluid to be measured A fluid temperature detecting element; a fixing member for fixing the insertion member to the hole of the apparatus main body; a pressure detecting element disposed in the fixing member; and a pressure of the fluid to be measured communicating with the hole. Said fixed to act on the sensing element Tube flow measuring device, characterized in that a pressure passage formed wood. The in-pipe flow rate measuring device according to claim 1, wherein a thermal flow rate detecting element, a fluid temperature detecting element, and a pressure detecting element are detachably arranged with respect to the apparatus main body. The in-pipe flow rate measuring device according to claim 1 or 2, wherein the pressure detecting element is disposed at a position away from the vortex generating portion in the pressure channel communicating with the bypass channel. The in-pipe flow rate measuring device according to any one of claims 1 to 3, wherein a mounting portion of the thermal flow velocity detecting element is fixed by welding to a distal end of the insertion member.

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