JP2007147418A - Vortex flowmeter having vibration transmitting means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vortex flowmeter capable of stably measuring the flow rate of fluid containing adhesive material, and stably measuring the flow rate of wet gas or gas measured in a state close to the dew point. <P>SOLUTION: The vortex flowmeter includes a measuring tube 23 that is disposed inside a flow tube 22 and passes fluid 33 to be measured, a vortex generator 24 disposed in a measuring tube 23, and a support 25 that is extended in the axial direction of the vortex generator 24 and supports the measuring tube 23. In the vortex flowmeter, stagnation is generated in the fluid 33 to be measured by a stagnation generating section existing in the vortex generator 24. The vortex flowmeter 21 has vibration transmitting means 27 (27a-27d) for transmitting vibration to the boundary surface between the stagnation generating section and the fluid 33 to be measured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vortex flowmeter that detects a change based on a Karman vortex generated by a vortex generator and measures a flow rate.

A vortex flow meter is known as a flow meter for measuring the flow rate of a fluid to be measured flowing in a flow tube. As is well known, when a vortex generator is arranged in a fluid flow, the vortex flowmeter is the number of Karman vortices (vortex frequency) generated from the vortex generator within a unit time within a predetermined Reynolds number range. Is proportional to the flow rate regardless of gas or liquid. This proportionality constant is called the Strouhal number. Examples of the vortex detector include a thermal sensor, a strain sensor, an optical sensor, a pressure sensor, an ultrasonic sensor, and the like, which can detect a thermal change, a lift change, and the like due to the vortex. The vortex flowmeter is a simple flowmeter that can measure the flow rate without being affected by the physical properties of the fluid to be measured, and is widely used for measuring the flow rate of gas or fluid (see, for example, Patent Document 1).
Japanese Patent No. 2869054 (Page 3, Fig. 1)

  In FIG. 10, for example, in the case of measuring the flow rate of flue gas or the flow rate of a fluid containing an adhering substance, the vortex generator 1 having a substantially triangular cross section is solid on the stagnation generating portion 3 facing upstream of the fluid 2 to be measured. Adheres and the deposit 4 as shown in the figure is formed. When the deposit 4 is formed, the Strouhal number increases and the instrumental difference of the vortex flowmeter shifts in the plus direction, or the generation of Karman vortices becomes irregular.

  As the above countermeasure, it is conceivable to change the cross-sectional shape of the vortex generator 1 to the vortex generator 5 shown in FIG. The vortex generator 5 is formed in a substantially rhombic cross section close to a state in which an adhesive substance is sufficiently accumulated in advance.

  Here, the vortex generator 5 will be described. The vortex generator 5 is formed with rectangular protrusions 6 (see FIGS. 11 and 12) at corners in a direction orthogonal to the flow of the fluid 2 to be measured. Yes. The protrusion 6 is formed to obtain a stable peeling point. Reference numeral 7 indicates a peeling point. In the vortex generator 5, a standing vortex 9 is generated in the vicinity of the side surface 8 on the upstream side of the protrusion 6, thereby causing a submerged action. In FIG. 12, reference numeral 10 denotes a peeling shear layer, and 11 denotes a peeling area.

  However, the above countermeasure has a problem that the adhesive substance 12 rarely deposits on the side surface 8 of the protrusion 6 as shown in FIG. If the adhesive substance 12 is deposited, the peeling point becomes unstable (the peeling shear layer 10 is along the top surface of the protrusion 6), so that the above countermeasure is not a complete countermeasure. Has a problem.

  On the other hand, in gas measurement or the like, for example, a means for instantaneously blowing nitrogen gas or the like to a site where adhesion is predicted (for example, a stagnation point) is provided, and this is activated when adhesion occurs to blow off the adhesive substance. Such measures can be considered (not shown).

  However, the above-mentioned measures for blowing off the adhering substance add an extra substance to the fluid, thereby deteriorating the flow rate measurement accuracy, and in some cases, harming the physical properties of the fluid and causing non-uniformity of the fluid. It has the problem that it ends up.

  Considering a case where the vortex flowmeter is used in an environment close to a humid gas or a dew point with reference to FIG. 14, in the peeling region 15 downstream of the peeling point 14 of the vortex generator 13, it is close to the peeling point 14. Since the flow of the fluid 16 to be measured is throttled and the flow velocity is increased, the pressure is locally reduced. Moreover, since the said part leaves | separates from the formation area of Karman vortex 17, a flow will also stagnate.

  Therefore, in combination with these, the above-mentioned part has a problem that the liquid 18 contained in the gas or the liquid 18 liquefied by negative pressure stagnates on the side surface of the vortex generator 13. When the boundary condition near the separation point 14 changes, the flow becomes unstable, the regularity of vortex generation is lost, and the instrumental error is deteriorated.

  The present invention has been made in view of the above-described circumstances, and can stably measure the flow rate of a fluid containing an adhesive substance, or the flow rate of a gas measured in a state close to a wet gas or a dew point. It is an object of the present invention to provide a vortex flowmeter capable of stably measuring the flow rate.

  The vortex flowmeter of the present invention according to claim 1 (vortex flowmeter provided with vibration transmission means) according to the present invention, which has been made to solve the above-mentioned problems, is provided inside a flow tube and allows a measurement pipe to pass a fluid to be measured; A vortex flowmeter comprising: a vortex generator provided in the measurement tube so as to face the flow of the fluid to be measured; and a support that extends in the axial direction of the vortex generator and supports the measurement tube, In the vortex flowmeter in which stagnation occurs in the fluid to be measured due to the stagnation generating portion existing in the vortex generator, vibration transmitting means for transmitting vibration to the boundary surface between the stagnation generating portion and the fluid to be measured is further provided. It is characterized by comprising.

  According to the present invention having such a feature, in the case of measuring a fluid containing an adhesive substance, it is possible to make adhesion difficult by vibrating the boundary surface between the stagnation generating portion and the fluid to be measured. Further, in the case of measurement of a gas that is measured in a state close to a wet gas or a dew point, the attached liquid can be vaporized and removed. The operation of the vibration transmitting means is preferably performed during flow rate measurement or intermittently. Examples of the vibration transmitting means include mechanisms and devices that generate ultrasonic vibrations, and mechanisms and devices that use the action of coils and magnets.

  A vortex flowmeter comprising the vibration transmission means of the present invention according to claim 2 is the vortex flowmeter comprising the vibration transmission means according to claim 1, wherein the vortex flowmeter vibrates toward the boundary surface by forced vibration or excitation vibration by the vibration transmission means. It is characterized by transmitting.

  According to the present invention having such a feature, it is possible to give a degree of freedom to the mounting position of the vibration transmitting means. The mounting position can be directly attached to the vortex generator, attached to the measurement tube or support, or attached to a member constituting the vortex flowmeter outside the flow tube (for example, an attachment tube connected to the flow rate converter). Assume that attachment is an example.

  According to the present invention described in claim 1, there is an effect that the flow rate of the fluid containing the adhesive substance can be stably measured. Moreover, there exists an effect that the flow volume of the gas measured in the state close | similar to wet gas or a dew point can be measured stably.

  According to the second aspect of the present invention, since the boundary surface between the stagnation generating portion and the fluid to be measured is vibrated, there is an effect that the adhesion substance can be efficiently prevented and removed. In addition, the liquid can be efficiently vaporized and removed.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a vortex flowmeter of the present invention, (a) is a front view of a state attached to a flow tube, (b) is an enlarged view around a vortex generator of (a), (C) is a side view around the vortex generator.

  In FIG. 1, reference numeral 21 indicates the vortex flowmeter of the present invention. Here, the vortex flowmeter 21 is of the type inserted into the flow tube 22 (assumed to be an example), and includes a measurement tube 23 provided in the flow tube 22 and a measurement tube 23 provided therein. The vortex generator 24, the vortex detector (not shown), the support body 25 that supports the measurement tube 23, and the support protrusion 26 that is provided integrally with the support body 25 are configured.

  The vortex flowmeter 21 includes the following external components and the vibration transmission means 27 as the gist of the present invention in addition to the internal components from the measurement tube 23 to the support convex portion 26 described above. Configured. That is, the vortex flowmeter 21 is provided on the mounting flange 28, the mounting cylinder 29 provided on the mounting flange 28, the flow rate converter 30 fixed so as to be continuous with the tip of the mounting cylinder 29, and the flow rate converter 30. The electric wire connecting portion 31 and the vibration transmitting means 27 are further provided.

  The vortex flowmeter 21 is characterized in that it includes a vibration transmitting means 27 in addition to a known configuration (for example, a configuration disclosed in Patent Document 1 in the background art section). The vibration transmitting means 27 is for transmitting vibration to a boundary surface 34 between a stagnation generating portion 32 (to be described later) of the vortex generator 24 and the fluid 33 to be measured, and is directly attached to the vortex generator 24 or measured. It is assumed that there are several attachment forms such as attachment to the tube 23 and the support 25 or attachment to the attachment cylinder 29.

  In the present embodiment, the vibration transmitting means 27 is slightly different depending on the mounting form. In the case of the vortex generator 24, the vibration transmission means is 27a (or 27a '), in the case of the measuring tube 23, the vibration transmission means is 27b, in the case of the support 25, the vibration transmission means is 27c, and in the case of the mounting cylinder 29 Suppose that the vibration transmitting means is 27d.

  In this embodiment, the vibration transmitting means 27a (or 27a ′) is assumed to be a small ultrasonic vibrator. Further, the vibration transmitting means 27b to 27d are, for example, those composed of ultrasonic vibrators (not limited to ultrasonic vibrators, any mechanism or apparatus capable of generating sufficient vibrations). For example, mechanisms and devices that use the action of coils and magnets, mechanisms and devices that use the action of sound pressure (sound waves), and the action of eddy currents). When the vibration transmitting means 27b to 27d are composed of the above-described ultrasonic vibrator, it is assumed that the vibration transmitting means 27b to 27d includes a clamp or the like dedicated for attachment.

  The vibration transmitting means 27a is configured to forcibly vibrate the boundary surface 34 when attached to the vortex generator 24. Further, when attached to any one of the measurement tube 23, the support 25, and the mounting cylinder 29, the boundary surface 34 is vibrated by excitation vibration excited by any one of the vibration transmitting means 27b, 27c, and 27d. It is configured as follows.

  The vibration transmission means 27 (27a to 27d) vibrate a boundary surface 34 between a stagnation generating portion 32 and a fluid to be measured 33, which will be described later, to efficiently prevent or remove the adhesion substance, or efficiently. It is configured for the purpose of vaporizing the liquid and removing it. According to the vortex flowmeter 21 of the present invention, the flow rate can be stably measured by providing the vibration transmitting means 27 (27a to 27d).

  Hereafter, each said structure is demonstrated.

  The flow tube 22 is formed in a circular cylindrical shape. The flow tube 22 is formed so that the fluid to be measured 33 flows through the flow tube 22. Although the flow tube 22 is illustrated horizontally in the present embodiment, it is assumed that the actual measurement can be performed not only horizontally but also vertically, for example.

  The flow tube 22 has a mounting hole 35 penetrating the tube wall. The attachment hole 35 is formed so as to open in a direction orthogonal to the axial direction of the flow tube 22 (in this embodiment, the Y direction in the figure). The mounting hole 35 is formed as a cylindrical portion having a size that allows the internal constituent member of the vortex flowmeter 21 to be inserted therein. A mounting flange 36 is coupled to the tip of the mounting hole 35. The attachment flange 36 is formed so as to be liquid-tightly joined to the attachment flange 28 of the vortex flowmeter 21.

  The measurement tube 23 is formed in a circular cylindrical shape having a smaller diameter than the flow tube 22. The measurement tube 23 is formed to pass the fluid 33 to be measured. In the present embodiment, such a measuring tube 23 is disposed at a position where this axis substantially coincides with the axis of the flow tube 22.

  The vortex generator 24 is a part for generating Karman vortices in the measurement tube 23. In this embodiment, the upstream side of the flow of the fluid 33 to be measured has a substantially rectangular cross section, and the downstream side has a substantially cross sectional home. It is formed to be a base-shaped column (the shape is an example). It is assumed that the vortex generator 24 is subjected to various processes as described later according to the form of the vibration transmitting means 27 (27a to 27d) (see the vortex generators 24a to 24g in FIG. 2 and subsequent figures).

  Examples of the vortex detector (not shown) include a thermal sensor, a strain sensor, an optical sensor, a pressure sensor, and an ultrasonic sensor.

  The support body 25 is cylindrical and is formed to extend in the axial direction of the vortex generator 24 (in this embodiment, the Y direction in the figure). The support 25 stores therein a signal line and the like connected to a vortex detector (not shown) and the flow rate converter 30. The support protrusion 26 is coupled to the support 25. The support convex portion 26 is provided in order to reduce the turbulence effect of the fluid flowing into the mounting hole 35.

  A mounting cylinder 29 provided on the mounting flange 28 has a cylindrical shape and is provided to store a signal line and the like from the support body 25. The flow rate converter 30 has a function of amplifying and shaping a vortex signal detected by a vortex detector (not shown) and converting it into a digital or analog output signal. The output signal converted by the flow rate converter 30 is output to an external device via the electric wire connection portion 31.

  Next, the vortex generator 24 (24a to 24g) and the vibration transmitting means 27 (27a to 27d) will be described with reference to FIGS.

  2A and 2B are views showing a state in which the vibration transmitting means 27a is attached to the vortex generator 24a, where FIG. 2A is a perspective view, FIG. 2B is a cross-sectional view, and FIG. FIG. 6D is a schematic diagram of the state of shake when the stagnation generating portion is vibrated in the tertiary mode.

  In FIG. 2, the vortex generator 24a has a columnar shape, and its outline is formed in a substantially home base shape (assumed as an example). The vortex generator 24a is arranged and formed so that the flat surface on the upstream side of the fluid to be measured 33 is orthogonal to the flow. The vortex generator 24a is formed in such a shape that a measured fluid 33 passes through the left and right sides to generate Karman vortices. The upstream surface causes the measured fluid 33 to stagnate due to this arrangement and the flow of the measured fluid 33. That is, the upstream surface is a stagnation generating portion 32 that generates stagnation.

  The vibration transmitting means 27a is positioned on the back side of the stagnation generating part 32 in order to transmit the vibration to the boundary surface 34 between the stagnation generating part 32 and the fluid 33 to be measured, in other words, for forcedly vibrating the stagnation generating part 32. It is attached to do. The vortex generator 24a has a space 37 as shown, for example, in order to attach the vibration transmitting means 27a. Further, the vortex generator 24a is configured, for example, in a two-part structure as shown in the figure in order to attach the vibration transmission means 27a (the fixing of the two members is, for example, bolted).

  In the above configuration, when the vibration transmitting means 27a is operated and the stagnation generating portion 32 is forcibly vibrated in the primary mode, the boundary surface 34 vibrates as shown in FIG. When forced vibration is performed in the tertiary mode, the boundary surface 34 vibrates as shown in FIG. Therefore, when the vibration transmitting means 27a is operated at the time of flow rate measurement or intermittently, it is possible to make it difficult to adhere the adhesive substance in the case of measuring the fluid containing the adhesive substance. According to the present invention, it is possible to stably measure the flow rate of a fluid containing an adhesive substance.

  FIG. 3 is a cross-sectional view showing a state in which the vibration transmitting means 27a ′ is attached to the vortex generator 24b.

  In FIG. 3, the vortex generator 24b has a columnar shape, and its outline is formed in a substantially home base shape (assumed as an example). The vortex generator 24b is arranged and formed so that the flat surface on the upstream side of the fluid to be measured 33 is orthogonal to the flow. The vortex generator 24b is formed in a shape such that a Karman vortex is generated by passing the fluid 33 to be measured through the left and right sides. A side surface continuous with the upstream surface is formed in parallel to the flow of the fluid to be measured 33.

  Here, reference numeral 38 denotes a peeling point, 39 denotes a peeling shear layer, and 40 denotes a peeling area. Reference numeral 32 'denotes a stagnation generating portion in the vortex generator 24b. A vibration transmitting means 27a 'is attached to the side surface included in the stagnation generating portion 32'. The vibration transmitting means 27a 'is attached to forcibly vibrate the boundary surface 34' formed by the stagnation generating portion 32 '.

  In the above configuration, when the vibration transmitting means 27a 'is operated at the time of flow rate measurement or intermittently and the boundary surface 34' is forcibly vibrated, in the case of measurement of a gas that is measured in a state close to a wet gas or a dew point, the attached liquid is removed. It can be removed by vaporization. According to the present invention, there is an effect that it is possible to stably measure the flow rate of gas measured in a state close to wet gas or a dew point.

  4 to FIG. 8 show the boundary surface between the stagnation generating portion 32 (32 ′) and the fluid 33 to be measured by the excitation vibration excited by any one of the vibration transmitting means 27b, 27c, and 27d including, for example, an ultrasonic vibrator. It is a perspective view which shows the example of the vortex generators 24c-24g which 34 (34 ') vibrates.

  In FIG. 4, the vortex generator 24c is formed with a slit 41 penetrating from the upper surface to the lower surface. The slit 41 is formed in the vicinity of the stagnation generating portion 32 (the slit 41 may be filled with an elastic member 42 to fill the space). The vortex generator 24c is configured such that the boundary surface 34 between the stagnation generating portion 32 and the fluid to be measured 33 vibrates in the direction of the arrow in the figure by excitation vibration.

  In FIG. 5, the vortex generator 24d is formed with slits 41 penetrating between the left and right tapered side surfaces. The slit 41 is formed so as to be located in the middle of the vortex generator 24d (the slit 41 may be filled with an elastic member 42 to fill the space). In the vortex generator 24d, the boundary surface 34 between the stagnation generating portion 32 and the fluid to be measured 33 is vibrated in the direction of the arrow in the figure by excitation vibration.

  In FIG. 6, the vortex generator 24e is formed with a slit 41 penetrating between the left and right side surfaces. The slit 41 is formed in the vicinity of the stagnation generating portion 32 (the slit 41 may be filled with an elastic member 42 to fill the space). In the vortex generator 24e, the boundary surface 34 between the stagnation generating portion 32 and the fluid to be measured 33 is vibrated in the direction of the arrow in the figure by excitation vibration.

  In FIG. 7, the vortex generator 24f is formed with a slit 41 penetrating in the flow direction of the fluid to be measured 33. That is, the slit 41 is formed so as to penetrate between the front and rear surfaces of the vortex generator 24f (the slit 41 may be filled with the elastic member 42 to fill the space). In the vortex generator 24f, the boundary surface 34 'between the stagnation generating portion 32' and the fluid to be measured 33 is vibrated in the direction of the arrow in the figure by excitation vibration.

  In FIG. 8, recesses are formed on the left and right side surfaces of the vortex generator 24 g, and a diaphragm (vibrating element) 43 is attached via an elastic body 44. The diaphragm 43 is formed so as to extend in the vertical direction of the vortex generator 24g. In the vortex generator 24g, the vibration plate 43, the stagnation generating portion 32 ', and the boundary surface 34' between the fluid to be measured 33 are vibrated in the direction of the arrow in the figure by excitation vibration.

  Next, a modification of the ultrasonic vibrator will be described with reference to FIG. FIG. 9 is a cross-sectional view showing a modification of the ultrasonic vibrator.

  In FIG. 9, the ultrasonic vibrator as the vibration transmitting means 27b is inserted into the vortex generator 24 with the distal end portion 45 extended. The ultrasonic vibrator as the vibration transmitting means 27b is configured to be able to efficiently transmit vibration to the vortex generator 24.

  In addition, although not limited to the ultrasonic vibrator of FIG. 9, when this ultrasonic vibrator is used intermittently, it can be used as a vortex detector. Regarding the direction of attachment of the ultrasonic vibrator, the X direction or the like is considered in addition to the attachment in the Y direction. ,

  In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

It is a figure which shows one Embodiment of the vortex flowmeter of this invention, (a) is a front view of the state attached to the flow tube, (b) is an enlarged view around the vortex generator of (a), (c) FIG. 3 is a side view around the vortex generator. It is a figure which shows the state which attached the vibration transmission means to the vortex generator, (a) is a perspective view, (b) is sectional drawing, (c) is the state of the shake when vibrating a stagnation production | generation part in a primary mode. (D) is a schematic diagram of a shake state when the stagnation generating portion is vibrated in the tertiary mode. It is sectional drawing which shows the state which attached the vibration transmission means to the vortex generator. It is a perspective view which shows the 1st example of the vortex generator which the boundary surface of a stagnation production | generation part and a to-be-measured fluid vibrates by the excitation vibration excited by a vibration transmission means. It is a perspective view which shows the 2nd example of the vortex generator which the boundary surface of a stagnation production | generation part and a to-be-measured fluid vibrates by the excitation vibration excited by the vibration transmission means. It is a perspective view which shows the 3rd example of the eddy generator which the interface of a stagnation production | generation part and a to-be-measured fluid vibrates by the excitation vibration excited by a vibration transmission means. It is a perspective view which shows the 4th example of the eddy generator which the interface of a stagnation production | generation part and a to-be-measured fluid vibrates by the excitation vibration excited by a vibration transmission means. It is a perspective view which shows the 5th example of the vortex generator which the boundary surface of a stagnation production | generation part and a to-be-measured fluid vibrates by the excitation vibration excited by the vibration transmission means. It is sectional drawing which shows the modification of an ultrasonic vibrator. It is explanatory drawing of the state in which the vortex generating body and adhesive substance of the prior art example were deposited. It is explanatory drawing used as the modification of the vortex generator of the prior art example in FIG. It is an enlarged view in the circle A of FIG. FIG. 13 is an explanatory diagram of a state in which an adhesive substance is deposited on FIG. It is explanatory drawing of the state which the liquid stagnated on the side surface of the vortex generator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Vortex flowmeter 22 Flow pipe 23 Measuring pipe 24 Vortex generator 25 Support body 26 Support convex part 27 Vibration transmission means 28 Mounting flange 29 Mounting cylinder 30 Flow converter 31 Wire connection part 32 Stagnation generating part 33 Fluid to be measured 34 Boundary Surface 35 Mounting hole 36 Mounting flange 37 Space 38 Peeling point 39 Peeling shear layer 40 Peeling area 41 Slit 42 Elastic member 43 Diaphragm 44 Elastic body 45 Tip portion

Claims (2)

A measuring pipe provided inside the flow pipe for allowing the fluid to be measured to pass therethrough, a vortex generator provided in the measuring pipe so as to face the flow of the fluid to be measured, and extending in the axial direction of the vortex generator A vortex flowmeter comprising a support that supports the measurement tube, wherein the fluid under measurement causes stagnation due to a stagnation generating portion present in the vortex generator;
A vortex flowmeter comprising vibration transmission means, further comprising vibration transmission means for transmitting vibration to a boundary surface between the stagnation generating portion and the fluid to be measured. A vortex flowmeter comprising the vibration transmitting means according to claim 1,
A vortex flowmeter comprising a vibration transmitting means, wherein vibration is transmitted to the boundary surface by forced vibration or excitation vibration by the vibration transmitting means.

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