JP3049176B2 - Vortex flowmeter and vortex sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vortex sensor for a vortex flowmeter, and more particularly, to a cantilevered support of a vortex generator, which is inserted into the vortex generator to reduce the fluctuation pressure of a Karman vortex introduced into the vortex generator into torque fluctuation. The present invention relates to a converting vortex flowmeter and a vortex sensor.

[0002]

2. Description of the Related Art As is well known, when a vortex flow meter is provided with a vortex generator disposed in a fluid flow, the number of Karman vortices generated from the vortex generator per unit time is a certain Reynolds number. This is an estimated flow meter that utilizes the fact that it is proportional to the flow rate in several ranges. The generated vortex is detected by the vortex sensor as a flow change or a pressure change occurring around the vortex generator. These vortex sensors are fixedly attached to the vortex generator or detachably provided. The vortex flowmeter has a feature that its characteristics are determined only by the Reynolds number without being affected by the type of fluid such as gas or liquid, or the density or viscosity of the fluid. However, since the fluctuating pressure due to the generation of the Karman vortex is an amount proportional to the square of the density and the flow velocity of the measurement fluid, it is necessary to increase the sensitivity in a small flow rate range in order to expand the measurement range. In this respect, a vortex sensor of the type removably arranged in the vortex generator is advantageous.

The present applicant has proposed a vortex flowmeter in Japanese Patent Publication No. Sho 63-31726 in which the same sensor can be attached and detached regardless of the size of the vortex generator. FIG. 10 (a),
(B) is a diagram for explaining this conventional vortex flowmeter,
FIG. 10A is a cross-sectional view as viewed from the flow direction, and FIG. 10B is a cross-sectional view taken along line BB in FIG. In the figure, 31 is a tube, 32 is a vortex generator, 33 is a mounting surface, 34 is a pressure chamber, 3
5 is a pressure guiding hole, 36 is a cylinder, 37 is an elastic base material, 38 is a piezoelectric element, 39 is a filler, 40 is a vortex sensor, 41 is a flange,
42 is a lead wire.

In FIG. 10, a tube 31 is a main body interposed in a pipe through which a fluid to be measured flows.
2 are provided. The vortex generator 32 is provided with a concave portion penetrating the tube 31, and the concave portion serves as a pressure chamber 34, and a pressure guiding hole 35 penetrates both side walls of the pressure chamber 34 to communicate with the fluid to be measured. I have. On the other hand, a vortex sensor 40 is inserted into the pressure chamber 34. The vortex sensor 40 has a bottomed cylindrical vibrating tube 36 having a flange portion 41, and a pressure receiving plate 36 a formed integrally with the bottom of the vibrating tube 36 and an elastic mother member coaxially inserted into the vibrating tube 36. Material 37, piezoelectric elements 38, 38 attached to both sides of the elastic base material 37, a filler 39 and a lead wire 42 for integrally fixing the elastic base material 37 in the vibration tube 36.
It consists of

[0005] The vortex sensor 40 is cantilevered to the tube 31 at a mounting surface 33 formed on the tube at a flange 41 of the vibration tube 36. The fluctuating pressure due to the vortex is introduced into the pressure chamber 34 through the pressure guiding hole 35 and acts on the pressure receiving plate 36a. The pressure receiving plate 36a which has received the fluctuating pressure fluctuates around the position where the cantilever is fixed, and this fluctuation is transmitted to the piezoelectric element via the filler 39 and an electric signal (charge) corresponding to the vibration is transmitted from the lead wire 42. Is output.

[0006] However, the vibration tube 2 of the above-mentioned conventional vortex sensor.
6 is cantilevered by a flange 31, and includes piezoelectric elements 38,
38 makes a simple vibration with the jaw 41 as a fulcrum. The vortex flow meter is interposed in the flow tube and is vibrated by external vibration together with the flow tube, and the vibrating tube 26 vibrates accordingly. In particular, when the vibration is in phase with the vortex signal, an expensive compensation means is required to cancel the external vibration. Also, since the fluctuating pressure is proportional to the square of the flow velocity, an attempt is made to increase the flow sensitivity by increasing the small flow sensitivity. However, as described above, since the micro vibration is constantly applied to the piping system, the fluctuation is stably small. I could not raise the flow limit. The external impact means the occurrence of a mispulse of the flow pulse, which lowers the reliability.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to detect a vortex flow meter and a vortex sensor which are hardly affected by external vibration and which detect a highly reliable vortex signal. Things.

[0008]

To achieve the above object, the present invention provides (1)
A main body through which a measurement fluid flows, and a columnar body having both ends fixed inside the main body, and one end of which is axially opened with a pressure chamber and an opening on each side .
Opposing diagonals of the pressure chamber from
A vortex generator having a pair of pressure guide paths for introducing a measurement fluid pressure to both upper corners, and a vortex generator inserted with a slight gap into the pressure chamber ;
That a pressure receiving plate, it has a vortex sensor that detects the fluctuating pressure based on a Karman vortex is introduced into the pressure chamber from the pressure guide hole as alternating torsional vibration of the pressure receiving plate, and further,
(2) The vortex sensor of (1) is attached with the pressure receiving plate at one end.
A vibration tube with a cylindrical body and having a flange for supporting cantilever the tubular body, a transmission shaft having one end fixed coaxially to said pressure receiving plate side of the vibrating tube, the other end of said transfer shaft And torque detecting means for detecting torque acting on the pressure receiving plate between the vibration tube and the vibration tube via the transmission shaft.
Was that, furthermore, (3) vortex sensor odor <br/> Te, said a vibrating tube and or said torque detecting means and said transmission shaft, said transmission shaft and substantially perpendicular to the plane of the plate spring (1) connected via, it has secured movably said transmission shaft in the axial direction only, even in the vortex sensor (4) above (1), before
Serial slits provided in the axial direction of said transfer shaft connecting the vibrating tube and or said torque detecting means and said transmission shaft, it has secured movably said transfer shaft in the axial direction, and further, (5) the ( In 1) or 3) , the vortex sensor is inserted into the pressure chamber with a small gap, the pressure receiving plate having a concave portion, a vibrating tube having a flange for cantilevering the pressure receiving plate, and one end of the vibration tube. A torque transmitting shaft fixed coaxially to the vibrating tube in the concave portion, and connected between the other end of the transmitting shaft and the vibrating tube to detect a torque acting on the pressure receiving plate via the transmitting shaft. it was composed of a torque detecting means, further, (6) a vortex sensor (1), before having a recess
A vibration tube including a pressure receiving plate and a mounting flange, a torque transmission shaft having one end fixed coaxially with a concave portion of the vibration tube and a connection portion at the other end, and the vibration being detachably attached to a connection portion of the transmission shaft. and this <br/> constructed from a torque detection means which is fixed to the tube, and further, the pressure receiving plate having a connecting portion a vortex sensor, which is disposed within the recess and recess (7) wherein (1) And a vibration tube comprising a mounting flange, and a transmission shaft having a joint at one end for detachably connecting the connection portion and the axial direction,
It was composed of a torque detecting means for detecting the torque between the fixed to the other end of said transfer shaft the vibrating tube, and further,
Connection (8) and body measurement fluid flows, and a lower vortex generator having one end within the body is fixed and the lower portion vortex generator coaxial with the upper vortex generator, and said main body and upper vortex shedder And a torque detecting means for detecting a torque caused by Karman vortex acting on the upper vortex generator. (9) In (8), the center of gravity of the upper vortex generator is coaxial with the torque detecting means. A hole is formed in the end of the upper vortex generator so as to be on the upper side . Hereinafter, a description will be given based on examples of the present invention.

FIGS. 1A, 1B, and 1C are partial cross-sectional views for explaining an example of a vortex flowmeter according to the present invention.
1A is a partial cross-sectional view in the flow Q direction, FIG. 1B is a cross-sectional view taken along the line BB of FIG. 1A, and FIG.
1A is a cross-sectional view taken along line CC of FIG.
Is a vortex generator, 3 is a pressure chamber, 4 and 5 are pressure guiding holes, 6 is a vibrating tube, 7 is a concave portion, 8 is a holding member, 9 is a transmitting member, and 10 and 1
1, 12 and 13 are piezoelectric elements, 14 is a transmission shaft, and 15 is a seal ring.

In FIG. 1A, the vortex generator 2 is shown in FIG.
A columnar body having an isosceles triangular cross section as shown in (b),
Both ends are fixed to a cylindrical main body 1 through which a measurement fluid flows. A pressure chamber 3 is bored in the vortex generator 2 in the axial direction, and the pressure chamber 3 communicates with pressure guiding holes 4, 5 opened on the side surface of the vortex generator 2. The pressure guiding holes 4 and 5 are
Are formed at predetermined intervals Δ without crossing each other when viewed from the axial direction.

FIGS. 2A and 2B are views for explaining an example of the pressure guiding holes 4 and 5 of the vortex generator 2 according to the present invention, and FIG. Sectional view of the position, FIG.
Is a cross-sectional view at the position of the pressure guiding hole 4. Fig. 2 (a), (b)
As shown in FIG. 3, pressure guiding passages 4a, 4 extending in the axial direction at positions sandwiching the pressure chamber 3 and communicating with the pressure chamber 3 are formed in the pressure guiding holes 4, 5, respectively.
b and 5a, 5b are open.

On the other hand, a pressure receiving plate 6a attached to one end of the vibration tube 6 is inserted into the pressure chamber 3 with a slight gap from the pressure chamber 3. As shown in FIG. 1A, the vibrating tube 6 is a cylindrical body having a bottomed concave portion 7 having a pressure receiving plate 6a at one end side, and the cylindrical body has a mounting flange 6c at an intermediate portion. The lower part of the mounting flange 6c comprises a bottomed cylinder 6b and the upper part comprises an upper opening cylinder 6d, which are integrally formed. The vibrating tube 6 is one element of the vortex sensor of the present invention. The vortex sensor includes a vibrating tube 6, a transmission shaft 14, a holding member 8, a transmitting member 9, and piezoelectric elements 10, 11, 12, and 13.
It consists of

In the vortex sensor composed of the above elements, one end of the transmission shaft 14 is fixed to the bottom of the cylindrical body 6b coaxially with the concave portion 7 of the vibration tube 6, and the transmission member 9 of a square pole is coaxially fixed to the other end. I do. On the other hand, on the outer periphery of the transmission member 9, a cylindrical holding member 8 fixed to the inner wall surface of the upper opening 6d is provided. The holding member 8 is made of an insulating material and has a rectangular through hole of the same shape that is slightly larger than the square outer periphery of the transmission member 9 made of a conductive material, and a rectangular gap between the holding member 8 and the transmission member 9 is formed. As shown in FIG. 1C, the piezoelectric elements 10, 1 each polarized in the thickness direction.
1, 12, 13 are fixed. Here, the piezoelectric elements 10, 11 and 12, 13 on the opposite sides are connected to each other, and the transmission member 9 is grounded to the main body 1 via the vibration tube 6. The vortex sensor configured as described above is a seal ring 1
5 and bolted to the main body 1 by the mounting flange 6c.

Next, the operation of the vortex flowmeter configured as shown in FIG. 1A will be described. When the fluid flows in the direction of arrow Q, a Karman vortex is generated below the vortex generator 2, and a fluctuating pressure is generated accordingly. This fluctuating pressure is applied to the pressure chamber
However, since the pressure receiving plate 6a is inserted into the pressure chamber 3, the fluctuating pressure acts on the pressure receiving plate 6a. Pressure pressure guide hole 4 is in the high vortex cycles than the pressure of the pressure guide hole 5, the pressure P ₁ of the pressure guide hole 4 as shown in FIG. 1 (b), the pressure receiving plate shown across the pressure receiving plate 6a It acts in the opposite direction with respect to the vertical direction of 6a. The pressure P ₂ of the pressure guide hole 5 at this time, the pressure receiving plate 6a because they act in the opposite direction in the same manner the torque of the left is generated. Similarly, in the next vortex cycle, a rightward torque is generated, and an alternating torque synchronized with the Karman vortex is generated. The alternating torque presses the piezoelectric elements 9, 10, 11, and 12 via the transmission shaft 14 to generate electric charges corresponding to the torque.

FIGS. 3A and 3B are tables for explaining the relationship between a signal generated in the piezoelectric element and a signal. FIGS. 3A and 3B show signals based on Karman vortices, and FIGS. 3C to 3H show external vibrations. Is shown. Signals based on Karman vortex (a), (b)
Outputs a signal corresponding to the clockwise direction torque and the counterclockwise direction torque as described above. On the other hand, the signals (c) and (d) in the oblique direction with respect to the flow tube are the piezoelectric elements 10 and
The charges of 11, 12 and 13 are canceled out, and there is no signal output. Next, in the axial vibration of the flow tube shown in (e) and (f) and the vibration in the direction perpendicular to the flow tube shown in (g) and (h), opposite negative outputs are generated. However, the vibration in the axial direction of the flow tube is usually ignored, and only the vibration in the direction perpendicular to the flow tube needs to be considered. However, since the signal at this time is always a minus signal, this compensation is easily performed. be able to.

FIGS. 4A and 4B are views for explaining another embodiment of the vortex sensor according to the present invention. FIG.
4A is a sectional view, FIG. 4B is a perspective view of a portion B in FIG. 4A, and 16 is a leaf spring. 1 are given the same reference numbers as in FIG. FIG. 4 (a)
The transmission shaft 14 is not directly fixed to the vibration tube 6 but is connected via a flat leaf spring 16 having a surface perpendicular to the transmission shaft 14. Absorbs expansion or contraction as distortion of the leaf spring 16,
The torque fluctuation is not affected. The leaf spring 16 is connected to the bottom of the cylinder 6b directly or via an insertion member 16a. Further, the leaf spring 16 may be connected to the transmission member 9.

FIGS. 5A and 5B are diagrams for explaining still another embodiment of the vortex sensor according to the present invention.
(A) Sectional view seen from the flow direction. FIG. 5B shows FIG.
It is a perspective view of the B section of (a), in which 17 is a vibration tube, 18
Is a vertical groove, and the portions that operate in the same way as in FIG. 1 are given the same reference numerals as in FIG. The vibration tube 17 in the vortex sensor of FIG. 5A is composed of a pressure receiving plate 17a and a mounting flange 17c, and the mounting flange 17c and the pressure receiving plate 17a are connected by a narrow portion 17b for reducing torsional rigidity. I have. A concave portion 7 is formed in the pressure receiving plate 17a, and a transmission shaft 1 is formed in a bottom portion.
One end of the transmission shaft 4 is fixed, but the transmission member 9 side has a two-sided width, and a longitudinal groove 18 is formed in the axial direction.
4 can slide freely and transmit torque.

FIG. 6 is a view for explaining still another embodiment of the vortex sensor according to the present invention. In the figure, 19 is a fixed housing, 2
Numeral 0 denotes a transmitting member, and the portions that operate in the same manner as in FIGS. 1 and 5 are given the same reference numerals as in FIGS. The vortex sensor shown in FIG. 6 has a structure in which the vibration tube 17 and the piezoelectric elements 10 to 13 are detachable.
It has an insertion portion 14a with both sides removed, and the insertion portion 14a and the transmission member 20 are fitted so as to be detachable in the direction of the arrow. Transmission member 20, holding member 8, and piezoelectric elements 10-1
Reference numeral 3 is integrally accommodated in a fixed housing, and the fixed housing 19 is detachably fixed in the upper opening 17d so that conversion is possible when the piezoelectric elements 10 to 13 become defective.

FIG. 7 is a view for explaining still another embodiment of the vortex sensor according to the present invention. In the figure, 21 is a sheath, 22 is a fixed ring, 23 is a joint end, and portions that perform the same operations as in FIGS. 1 and 6 are denoted by the same reference numerals as in FIGS. The vortex sensor shown in FIG. 7 is configured such that a transmission shaft 14 having piezoelectric elements 10 to 13 is detachably fixed to a vibration tube 17, and a longitudinal groove having a two-sided width or a rectangular cross section is provided at one end of the transmission shaft 14. Is fixed, and the fixed end 22 and the fixed wheel 22 fixed to the bottom surface of the concave portion 7 of the pressure receiving plate 17a are detachably engaged with each other.

FIG. 8 is a view for explaining another embodiment of the vortex flowmeter according to the present invention. In FIG.
Is a vortex sensor, and 26 is a protection cylinder. The vortex generator 2 of FIG. 8 is separated into an upper vortex generator 2b and a lower vortex generator 2a, one end of the lower vortex generator 2a is fixed in the main body 1, the other end is a free end, and the upper vortex generator 2b and a slight gap. A vortex sensor 25 is connected to the upper vortex generator 2b. The vortex sensor 25 is the same as the torque detection sensor shown in FIG.
b and the protective cylinder 23 coaxially attached thereto.
Further, the vortex sensor 25 is coaxially fixed to a fixing ring 24 attached to the wall surface of the main body 1. Since an alternating lift due to the generation of the vortex acts on the upper vortex generator 2b, the alternating lift can be detected by the vortex sensor 25 as a torque signal. At this time, the upper vortex generator 2b and the vortex sensor 25
Need to be joined by an axis passing through the center of gravity of the upper vortex generator 2b.

FIGS. 9A and 9B are views for explaining another embodiment of the vortex flow meter of FIG. FIG. 9A shows a hole for moving the center of gravity G. FIG. 9B is a diagram showing the operation. FIG. 9A shows a state in which a hole 26 having a predetermined size is formed in the upper vortex generator 2b so that the center of gravity G is moved coaxially with the vortex sensor 22. The upper vortex generator 2b is shown in FIG.
As shown in (1), the vortex sensor 25 is rotated alternately by the angle θ with the center of gravity G as a fulcrum, and only a complete alternating torsional vibration acts on the vortex sensor 25 without a bending moment.

[0022]

As is apparent from the above description, according to the present invention, since the signal due to the Karman vortex is detected as alternating torsional vibration, the influence of the flow tube vibration is only affected by the vibration in the flow tube axial direction and the direction perpendicular to the flow tube. . However, since there is almost no influence of vibration in the axial direction of the flow tube, only the influence of vibration in the direction perpendicular to the flow tube is substantially received. However, since this vibration effect becomes a noise component in one direction, it can be easily corrected, and a highly stable eddy signal can be detected with high sensitivity.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating an example of a vortex flowmeter according to the present invention.

FIG. 2 is a diagram for explaining an example of a vortex pressure guiding hole according to the present invention.

FIG. 3 is a table for explaining a relationship between a charge generated in a piezoelectric element and a signal.

FIG. 4 is a view for explaining another embodiment of the vortex sensor according to the present invention.

FIG. 5 is a view for explaining still another embodiment of the vortex sensor according to the present invention.

FIG. 6 is a view for explaining still another embodiment of the vortex sensor according to the present invention.

FIG. 7 is a view for explaining still another embodiment of the vortex sensor according to the present invention.

FIG. 8 is a view for explaining another embodiment of the vortex flowmeter according to the present invention.

FIG. 9 is a view for explaining another embodiment of the vortex flow meter of FIG. 8;

FIG. 10 is a view for explaining a conventional vortex flowmeter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main body, 2 ... Vortex generator, 3 ... Pressure chamber, 4, 5 ... Pressure guiding hole, 6 ... Vibration tube, 7 ... Depression, 8 ... Holding member, 9 ... Transmission member, 10, 11, 12, 13 ... Piezoelectric element, 14: transmission shaft, 15: seal ring, 16: leaf spring, 17: vibrating tube, 18: vertical groove, 19: fixed housing, 20: transmission member, 21
... sheath, 22 ... fixed ring, 23 ... joining end, 24 ... fixed ring, 25 ... vortex sensor, 26 ... protection cylinder.

Claims (9)

(57) [Claims] 1. A main body through which a measurement fluid flows, and a columnar body whose both ends are fixed inside the main body .
A vortex generator having a pair of pressure guiding passages for introducing a measurement fluid pressure at opposite corners on a diagonal line, and a small gap in the pressure chamber;
A pressure receiving plate which is inserted has, the pressure receiving plate fluctuating pressure based on a Karman vortex is introduced into the pressure chamber from the pressure guide hole
Further comprising a vortex sensor for sensing as alternating torsional vibration
A vortex flowmeter. 2. The vortex sensor is attached to the pressure receiving plate at one end.
A vibration tube with a cylindrical body and having a flange for supporting cantilever the tubular body, a transmission shaft having one end fixed coaxially to said pressure receiving plate side of the vibrating tube, the other end of said transfer shaft And torque detecting means for detecting torque acting on the pressure receiving plate between the vibration tube and the vibration tube via the transmission shaft.
A vortex flowmeter characterized by: Wherein in said vortex sensor, said a vibrating tube and or said torque detecting means and said transmission shaft is connected via a leaf spring said transfer axis substantially perpendicular plane, the transmission shaft in the axial direction 2. The device according to claim 1, wherein the first member is movably fixed.
Vortex flowmeter as described. Wherein in said vortex sensor, a slit is provided in the axial direction of said transfer shaft connecting the the vibrating tube and or said torque detecting means and said transmission shaft and secured movably said transfer shaft in the axial direction The eddy current according to claim 1, wherein
Meter . 5. The vortex flowmeter according to claim 1, wherein:
In addition, the vortex sensor is inserted into the pressure chamber with a small gap, the pressure receiving plate having a concave portion, and a vibration tube having a flange for cantilevering the pressure receiving plate; A torque transmission shaft coaxially fixed to the vibration tube, and torque detection means connected between the other end of the transmission shaft and the vibration tube, for detecting torque acting on the pressure receiving plate via the transmission shaft. Vortex flow characterized by comprising
Total . 6. A vibrating tube comprising the pressure receiving plate having a concave portion and a mounting flange, a torque transmission shaft having one end fixed coaxially with the concave portion of the vibrating tube and a connecting portion at the other end. 2. The vortex flowmeter according to claim 1, further comprising: torque detecting means detachably fixed to the vibration tube at a connection portion of the transmission shaft. 7. A vibrating tube comprising a pressure receiving plate having a concave portion and a connecting portion disposed in the concave portion and a mounting flange, and the one end of the vortex sensor is axially detachably connected to the connecting portion at one end. a transmission shaft having a catch which, vortex flowmeter according to claim 1, characterized by being configured from a torque detection means for detecting the torque between the fixed to the other end of said transfer shaft the vibrating tube. 8. A main body through which a measurement fluid flows, a lower vortex generator having one end fixed in the main body, an upper vortex generator coaxial with the lower vortex generator, and the upper vortex generator and the main body. A vortex flowmeter connected to the vortex flowmeter, wherein the vortex flowmeter comprises torque detection means for detecting torque due to Karman vortex acting on the upper vortex generator. 9. The flowmeter of claim 8, wherein the center of gravity of the upper vortex shedder is bored a hole in the upper vortex generator end such that the torque detecting means and coaxially .