JP2015206628A - vortex flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vortex flowmeter capable of measuring the flow rate regardless of the aperture of a fluid pipe.SOLUTION: The vortex flowmeter 1 of the present invention includes a flow channel body 2 including a main channel 3 through which a fluid flows, and a vortex generator 4 inserted into the flow channel body 2. The vortex generator 4 includes first bypass flow channels 7a and 7b extending in the direction orthogonal to the flow direction of the fluid flowing through the main channel 3. A flow sensor 12 for detecting the frequency of the flow of the alternation caused by the vortex generator 4 is disposed in a second bypass flow channel 13.

Description

The present invention relates to a vortex flowmeter for measuring the flow rate of a fluid to be measured flowing in a fluid pipe.

As a conventional vortex flowmeter, a bypass flow path is formed in a direction perpendicular to the traveling direction of a fluid to be measured with respect to a vortex generator disposed in a fluid pipe, and a microflow sensor (registered) is formed in the bypass flow path There is known a vortex flowmeter that detects a Karman vortex generated by a vortex generator and measures the flow rate of a fluid by arranging a trademark.
(For example, see Patent Document 1.)
JP 2004-93349 A

By the way, in the Japanese Industrial Standard JIS Z 8766, the Strouhal number St which is a dimensionless number is St = f · w / U (f: vortex frequency, w: width of the vortex generator, U: average flow velocity in the pipe line It is known that this Strouhal number St takes a substantially constant value regardless of the flow velocity. That is, it is possible to measure the flow rate of the fluid to be measured by detecting the frequency of Karman vortices generated alternately on the downstream side of the vortex generator having a substantially triangular cross-sectional shape.

On the other hand, there are various diameters of the fluid pipe through which the fluid to be measured flows. Regardless of the size of the diameter, the same microflow sensor (registered trademark) arranged in the bypass flow path can be used. It is common to be used. In Patent Document 1, a silicon substrate of a microflow sensor (registered trademark) disposed in a bypass channel is formed with a size of about 1 to 2 mm square. In order to mount this microflow sensor (registered trademark), a sealing member such as a glass hermetic seal is used, and the diameter of the sealing member needs to be about 10 mm. In addition, the diameter of the pipe having the microflow sensor (registered trademark) at the tip must be larger than that of the seal member in consideration of passing the connecting wire therethrough. Since the pipe is inserted into the hole provided in the vortex generator, the width of the vortex generator needs to be designed larger than the diameter of the pipe.

  Here, in order to generate a Karman vortex downstream of the vortex generator and detect its frequency, in Japanese Industrial Standard JIS Z 8766, the relationship between the width w of the vortex generator and the diameter D of the fluid pipe is: The basic dimensions are set as w = 0.28D. Based on this relationship, when the dimension of the width w of the vortex generator is calculated with respect to the representative value of the diameter D of the fluid pipe shown in FIG. 7, for example, when the diameter D of the fluid pipe is 20.0 (mm), The width w of the vortex generator is 5.60 (mm).

However, the configuration of the vortex flowmeter in Patent Document 1 is configured such that a pipe is inserted into a hole of a vortex generator having a substantially triangular cross-sectional shape. Therefore, for example, if the diameter D of the fluid pipe shown in FIG. 7 is 20.0 (mm) or less, a hole for inserting the pipe cannot be formed in the vortex generator. Therefore, when the diameter D of the fluid pipe is set to be smaller than 20.0 (mm), it is difficult to realize the vortex flowmeter having the structure of Patent Document 1.

  Accordingly, an object of the present invention is to provide a vortex flowmeter capable of measuring the flow rate regardless of the diameter of the fluid pipe.

The present invention, which has been made in view of the above problems, includes a flow path body having a main flow path through which a fluid flows, and a vortex generator inserted into the flow path body. Extending in a direction orthogonal to the flow direction of the fluid flowing through the main flow path, at least a first hole that becomes a part of the sub flow path is formed, and is generated inside the sub flow path by the vortex generator A sensor for detecting the frequency of the alternating flow is a vortex flowmeter provided inside the auxiliary flow path and at a place excluding the inside of the hole.

  The flow path structure further includes a flow path structure attached to the flow path body. The flow path structure extends in a direction parallel to the first hole and becomes a part of the sub flow path. At least a second hole is formed, the first and second holes communicate with each other, and the sensor may be provided inside the second hole.

  The flow path body has at least a second hole extending in a direction parallel to the first hole and serving as a part of the sub-flow path. The holes may be in communication, and the sensor may be provided inside the second hole.

  The first hole portion includes one hole opened at one end of the vortex generator and the other hole opened at the other end of the vortex generator. You may have the same central axis.

  According to the present invention, it is possible to provide a vortex flowmeter capable of measuring an accurate flow rate regardless of the diameter of the fluid pipe.

Hereinafter, a control device according to an embodiment of the present invention will be described with reference to the drawings.
In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, since the drawings are schematic, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  FIG. 1 is a front view of a vortex flowmeter 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of FIG. The vortex flowmeter 1 includes a vortex generator 4 that generates a Karman vortex in a fluid to be measured (not shown) flowing in the main flow path 3 of the fluid pipe 2, and the vortex flow generator 4 has a diameter D of the main flow path 3. It is a longer columnar member. The vortex generator 4 is inserted from a hole 5 formed in the wall of the fluid pipe 2 to the groove 5b so as to cross in the radial direction. The fluid pipe 2 is connected to a hollow joint 26 having a hexagonal cross section.

In the vortex generator 4, two bypass holes 6a and 6b are formed in a direction orthogonal to the traveling direction of the fluid to be measured (not shown) (the direction of arrow B in FIG. 1). The bypass holes 6 a and 6 b are opened to the vicinity of the central axis in the extending direction of the vortex generator 4. Further, the bypass holes 6 a and 6 b communicate with first bypass flow paths 7 a and 7 b opened inside the vortex generator 4. Further, two lateral holes 8 a and 8 b are formed in the vortex generator 4 so as to communicate with the first bypass flow paths 7 a and 7 b, respectively, and the through holes 31 a and 31 b formed in the fluid pipe 2 are formed. Communicate. Note that the term “communication” in this specification does not mean that two elements are connected without interposing other elements. For example, even when the bypass hole 6a and the lateral hole 8a are connected via the first bypass flow path 7a, the bypass hole 6a and the lateral hole 8a are expressed as “in communication”. Yes.

The main body 9 includes a flow path structure 10 and a lid 11. A second bypass flow path 13 is formed in the flow path structure 10, and the fluid flowing through the first bypass flow paths 7 a and 7 b formed in the fluid pipe 2 is supplied to the flow sensor 12. The channel structure 10 is fixed to the fluid pipe 2 so as to be guided to the second bypass channel 13 arranged. Therefore, the fluid to be measured that has flowed from the first bypass flow paths 7a and 7b of the fluid pipe 2 passes through the horizontal holes 14a and 14b and is formed in the flow path structure 10 of the main body. It flows into the bypass channel 13. The lid 11 is attached to the flow path structure 10 so as to cover a printed circuit board 25 and a flow sensor 12 described later.

  A flow sensor 12 for detecting the flow of the fluid to be measured is installed inside the second bypass flow path 13 formed in the flow path structure 10. A sensor chip 15 of the flow sensor 12 is simply shown in FIG. As shown in FIG. 3, the sensor chip 15 is provided with, for example, one heater 17 on a silicon substrate 16 and temperature sensors 18 and 19 made of small metal thin films on both sides of the heater 17. And 19 detects a temperature change on both sides of the heater 17 to obtain a fluid vibration detection signal. At this time, a predetermined electric power is supplied to the heater 17 to heat it to a constant temperature, a constant electric power is applied to the temperature sensors 18 and 19 on both sides of the heater, and a vibration waveform is generated at the midpoint between the temperature sensors 18 and 19. The signal is detected. Thereby, the flow rate of the fluid can be measured after calculating the detected signal as the number of vibrations per unit time.

  As shown in FIG. 4, the sensor chip 15 is mounted on a seal member 20, and the seal member 20 is fixed to a bracket 21. From the back surface of the seal member 20, a conductive wire 22 protrudes through a hollow portion of the bracket 21. The flow sensor 12 is inserted into a hole 23 formed in the flow path structure 10 and fixed to the flow path structure 10 by a bolt 24 through a bolt hole (not shown) provided in the header 21. The

  The printed circuit board 25 provided in the internal space of the lid body 11 is provided with an electric circuit composed of an electric device (not shown). A signal from the flow sensor 12 is processed by this electric circuit through the conductor 22. Is output as a measured flow rate. Further, on the printed circuit board 25, an unillustrated indicator lamp composed of LED elements or the like is provided to display a measured flow rate value and the like. A transparent window portion 27 is provided at a position corresponding to the indicator lamp of the lid 11, and the lighting state of the indicator lamp can be confirmed through the window portion 27. Although not particularly illustrated, the lid 11 may be provided with buttons for various setting operations by the user.

Next, regarding the formation process of the bypass holes 6a and 6b, the first bypass channels 7a and 7b, and the lateral holes 8a and 8b in the vortex generator 4, the cross-sectional views shown in FIGS. The description will be made with reference to FIGS. 6 (a) to 6 (d) showing cross-sectional views in the C cross section of FIGS. 5A to 5D, the front side of the drawing is the upstream side where the fluid flows.
FIG. 5 (a) is a cross-sectional view of the vortex generator 4 in which an O-ring groove 28 to be fitted upon attachment to the fluid pipe 2 is formed, and is shown in the cross-sectional view of FIG. 6 (a). Thus, the upstream end 4a of the vortex generator 4 has a width w. As shown in FIG. 5 (b), the vortex generator 4 is machined by drilling or the like so that the holes serving as the first bypass flow paths 7a and 7b have the same central axis. . Similarly, the lateral holes 8a and 8b shown in FIG. 5 (c) and the bypass holes 6a and 6b shown in FIG. 5 (d) are arranged in the direction from the outer surface of the vortex generator 4 to the first bypass channels 7a and 7b. Process toward. It is desirable that the alternating flow flowing into the bypass holes 6 a and 6 b is detected on the same axis as the vortex generator 4. Therefore, when the bypass holes 6a and 6b are processed from the outer surface of the vortex generator 4, they are processed in an oblique direction with respect to the first bypass flow paths 7a and 7b. Thereby, rather than processing the bypass holes 6a and 6b in the vertical direction with respect to the first bypass flow paths 7a and 7b, the alternating flow generated on the substantially horizontal coaxial line can be changed to the first bypass flow paths 7a and 7b. 7b can be introduced.

  When the vortex generator 4 is attached to the flow path body 2, an O-ring (not shown) is fitted into the groove 28 so that the openings 29 of the first bypass flow paths 7 a and 7 b are covered with the plate 30. The channel body 2 is fixed by a fixing means such as a screw. Note that the through holes 31a and 31b of the flow path body 2, the lateral holes 14a and 14b of the flow path structure 10, and the second bypass flow path 13 also include the bypass holes 6a and 6b of the vortex generator 4 and the first As with the bypass channels 7a and 7b and the horizontal holes 8a and 8b, it can be processed by drilling or the like, and the opening portion after processing uses a fixing means such as a plate 30 and screws. do it.

  By combining the flow path body 2, the vortex generator 4, and the main body 9 formed as described above, the bypass holes 6a and 6b, the first bypass flow paths 7a and 7b, the lateral holes 8a and 8b, and the through holes are formed. One passage T is formed by the holes 31a and 31b, the lateral holes 14a and 14b, and the second bypass passage 13. As a result, since the flow generated alternately by the vortex generator 4 passes through the flow path T and over the flow sensor 12, the vibration waveform signal due to the Karman vortex is detected and the flow rate of the fluid to be measured is measured. Things will be possible.

  As described above, in the vortex flowmeter of the present invention, the flow sensor 12 is not installed in the vortex generator 4, and the fluid passes through the first bypass flow paths 7a and 7b formed in the vortex generator 4. The flow sensor 12 is configured to flow outside the fluid pipe 2 and the flow sensor 12 is arranged outside the fluid pipe 2. Therefore, even when the diameter D of the main flow path 3 and the width w of the vortex generator 4 are designed to be small, the same regardless of the diameter D of the main flow path 3 and the width w of the vortex generator 4. The flow sensor 12 can be used to measure the fluid flow rate.

In the above-described embodiment, the example in which the second bypass flow path 13 is formed in the flow path structure 10 has been described. However, the bypass flow path 13 may be formed in the flow path body 2. Good. That is, it is not always necessary that the flow path structure 10 is formed, and the flow path 2 and the flow path structure 10 can be integrally formed. In this case, the lateral hole 14a and the through hole 31a, the lateral hole 14b and the through hole 31b are each formed as one hole penetrating to the right side of the sheet of the flow path structure 10 in FIG. What is necessary is just to comprise so that it may block. Therefore, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention, and include various embodiments and the like such as design changes within the scope of the present invention. Needless to say.

The front view of the vortex flowmeter which concerns on embodiment of this invention. A sectional view of the vortex flowmeter in FIG. The top view of a sensor chip. The external view of a flow sensor. Sectional drawing of the vortex generating body seen from the upstream through which the fluid flows. C sectional drawing of the vortex generator in FIG. The figure which showed the relationship between the diameter D of a fluid pipe | tube, and the width | variety w of a vortex generator.

DESCRIPTION OF SYMBOLS 1 Vortex flowmeter 2 Fluid pipe 3 Main flow path 4 Vortex generator 7a, 7b 1st bypass flow path 9 Main-body part 10 Flow path part structure 11 Lid body 12 Flow sensor 13 2nd bypass flow path

Claims (4)

A channel body having a main channel through which a fluid flows;
A vortex generator inserted into the flow path body,
The vortex generator extends at least in a direction perpendicular to the flow direction of the fluid flowing through the main flow path, and is formed with at least a first hole that becomes a part of the sub flow path,
A sensor that detects the frequency of the alternating flow generated inside the sub-flow channel by the vortex generator is provided inside the sub-flow channel and at a place other than the inside of the hole. A vortex flowmeter that is characterized. A flow path structure attached to the flow path body;
The flow channel structure has at least a second hole portion that extends in a direction parallel to the first hole portion and is a part of the sub flow channel,
The first and second holes communicate with each other,
The vortex flowmeter according to claim 1, wherein the sensor is provided inside the second hole. The flow path body has at least a second hole portion extending in a direction parallel to the first hole portion and serving as a part of the sub flow path,
The first and second holes communicate with each other,
The vortex flowmeter according to claim 1, wherein the sensor is provided inside the second hole. The first hole includes a pair of holes,
4. The vortex flowmeter according to claim 1, wherein each hole of the pair of hole portions is formed to have substantially the same central axis.