Vortex shedding flowmeter

Abstract

The invention provides a vortex shedding flowmeter, which belongs to the technical field of flow detection, and is provided with a measuring tube, a vortex generating body and a sensor are arranged in the measuring tube, the vortex generating body is arranged right behind the sensor, a front generating body is further arranged in the measuring tube, the front generating body is arranged right behind the vortex generating body, and the sensor is arranged in the front generating body. The circulation of the front generating body and the circulation of the vortex generating body are in the same direction and are synchronous, and a vortex cavity is formed between the front generating body and the vortex generating body; a rotational flow cavity is formed between the front generating body and the vortex generating body, the front generating body converts a non-rotational fluid into a rotational fluid and sends the rotational fluid into the rotational flow cavity, when the rotational fluid in the rotational flow cavity passes through the vortex generating body, vortexes generated by the front generating body and the vortex generating body are mutually overlapped, circulation is increased, and lift force generated by the vortexes is increased. Vortex street signals are stronger, clear and stable, and the method has high linearity and good repeatability.

Description

Technical Field

[0001] The present application belongs to the technical field of flow detection, and more specifically, relates to a vortex flowmeter. Background Art

[0002] Vortex flowmeter is a volume flowmeter that measures the volume flow rate of gas, steam or liquid, the volume flow rate under standard conditions or the mass flow rate, which is developed based on the Karman vortex principle. The characteristics of vortex flowmeter are small pressure loss, large measuring range and high precision. When measuring the volume flow rate under working conditions, it is almost unaffected by parameters such as fluid density, pressure, temperature and viscosity. Vortex flowmeter has no movable mechanical parts, so it has high reliability, low maintenance and long-term stability of instrument parameters.

[0003] The vortex flowmeter uses a piezoelectric stress sensor and can operate in the operating temperature range of -20℃ to +400℃. It is mainly used for flow measurement of industrial pipeline medium fluids, such as gas, liquid, steam and other media. When the fluid passes through the vortex flow transmitter in the pipeline, two rows of vortices proportional to the flow velocity are generated alternately up and down behind the vortex generator. The release frequency of the vortex is related to the average velocity of the fluid flowing through the vortex generator and the characteristic width of the vortex generator. Then the number of vortices is detected by the sensor, and the flow velocity of the fluid is determined based on the number of vortices.

[0004] Existing vortex flowmeters have the following disadvantages: vortex flowmeters use the principle of fluid oscillation to measure flow, and there is a vortex separation frequency that moves with the Reynolds number of the fluid and the vortex train wake is chaotic, which can easily cause vortex distortion or disappearance. The wake chaos phenomenon will have a feedback effect on the alternating generation of vortices, causing the vortex separation frequency to deviate, affecting the accuracy and repeatability of the vortex flowmeter; during measurement, the vibration of the measuring tube causes abnormal sensor detection, resulting in inaccurate flowmeter measurement; when the flow rate of the fluid is low, the amplitude of the signal is small, the vortex generated is small, and pulse loss will occur, resulting in the measurement accuracy of the flowmeter, affecting the minimum flow rate that the vortex flowmeter can measure. Summary of the invention

[0005] The purpose of the present invention is to make up for the deficiencies of the prior art and provide a vortex flowmeter. The technical solution adopted in this application is:

[0006] A vortex flowmeter is provided with a measuring tube, in which a vortex generator and a sensor are provided, and the vortex generator is arranged directly behind the sensor. The invention is characterized in that a front generator is also provided in the measuring tube, and the front generator is arranged directly behind the vortex generator. The circulation of the front generator is in the same direction and synchronous with the circulation of the vortex generator, and a vortex chamber is provided between the front generator and the vortex generator.

[0007] Preferably, the front generator and the vortex generator are both in the shape of right prisms, and the widths of the front generator and the vortex generator are the same; the bottom surface of the front generator is in a rhombus shape, and the bottom surface of the front generator is provided with a first diagonal and a second diagonal, and the direction of the first diagonal is parallel to the axial direction of the measuring tube.

[0008] Preferably, the inner angle of the bottom surface of the front shedder is in the range of 85 degrees to 95 degrees.

[0009] Preferably, the bottom surface of the front shedder is square.

[0010] Preferably, the bottom surface of the vortex generator is in an isosceles triangle shape or a "T" shape, and a bottom edge is provided at the rear end of the bottom surface of the vortex generator, the direction of the bottom edge is parallel to the direction of the second diagonal line, and the length of the bottom edge is equal to the length of the second diagonal line.

[0011] Preferably, the length of the second diagonal line is L, the shortest distance between the front shedder and the vortex shedder is S, and the ratio of L to S is in the range of 2.25 to 2.75.

[0012] Preferably, the nominal diameter of the test tube is DN, and the ratio of DN to L is in the range of 3.9 to 4.17.

[0013] Preferably, the ratio of DN to L is 4.

[0014] Preferably, a display and a converter are also provided, wherein the converter is provided between the sensor and the display; and the display is provided outside the measuring tube.

[0015] Preferably, flanges are provided at both ends of the measuring tube.

[0016] The advantages of the present invention are as follows:

[0017] A pre-generator, a vortex generator and a sensor are sequentially arranged in the measuring tube along the axial direction, and the circulation of the pre-generator and the vortex generator is made to be in the same direction and synchronous with the circulation of the vortex generator by controlling the geometrical dimensions, end surface shapes and distances of the pre-generator and the vortex generator;

[0018] A swirl chamber is provided between the front generator and the vortex generator. The front generator converts the irrotational fluid into a swirling fluid and sends it into the swirl chamber. When the swirling fluid in the swirl chamber passes through the vortex generator, the vortices generated by the front generator and the vortex generator are superimposed on each other, the circulation is increased, the lift generated by the vortex is increased, the vortex signal is stronger, clearer and more stable, and has higher linearity and better repeatability. Experimental verification shows that the vortex signal can be amplified by 2 to 10 times, and the loss of fluid pressure can be reduced. The vortices generated by the front generator and the vortex generator are superimposed on each other, so that the number of vortices is reduced, the operating frequency of the sensor is reduced, and the service life of the sensor can be extended.

[0019] A front generator and a vortex generator are provided at the same time. During the test verification, it is found that the technical effect of reducing the vibration of the measuring tube is achieved, thereby improving the signal-to-noise ratio. The existing vortex flowmeter needs to be installed with a straight steady-flow pipe of not less than 80 cm in length before and after. The present invention does not need to install a steady-flow pipe and can meet the measurement requirements, so it is more convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained like these drawings without paying any creative labor.

[0021] Figure 1 is a schematic diagram of a vortex flowmeter;

[0022] Figure 2 This is a schematic diagram of the vortex flowmeter from another angle;

[0023] Figure 3 It is a schematic diagram of the main view of the vortex flowmeter;

[0024] Figure 4 is a schematic diagram of a cross section of a vortex flowmeter;

[0025] Figure 5 It is a schematic diagram of the top view of the vortex flowmeter;

[0026] Figure 6 It is a stereogram of another cross section of the vortex flowmeter;

[0027] Figure 7 yes Figure 6 Front view of vortex flowmeter;

[0028] Figure 8 It is a schematic diagram of the vortex flowmeter of Example 12.

[0029] Explanation of symbols in the figure:

[0030] 1 is a measuring tube, 11 is a flange;

[0031] 2 is the vortex generator, 21 is the base, and 22 is the waist;

[0032] 3 is the sensor;

[0033] 4 is the front generator, 41 is the first diagonal line, 42 is the second diagonal line, and 43 is the inner angle;

[0034] 5 is a swirl chamber;

[0035] 6 is a converter. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] The vortex flowmeter provided in the embodiment of the present application is now described.

[0038] Example 1

[0039] like Figures 1 to 7 As shown, a vortex flowmeter is provided with a measuring tube 1, a vortex generator 2 and a sensor 3 are provided in the measuring tube 1, the vortex generator 2 is arranged directly behind the sensor 3, and a front generator 4 is also provided in the measuring tube 1, the front generator 4 is arranged directly behind the vortex generator 2, the circulation of the front generator 4 is in the same direction and synchronous with the circulation of the vortex generator 2, and a swirl chamber 5 is provided between the front generator 4 and the vortex generator 2. In this embodiment, the sensor 3 adopts a piezoelectric sensor.

[0040] A pre-generator 4, a vortex generator 2 and a sensor 3 are sequentially arranged in the measuring tube 1 along the axial direction. By controlling the geometrical dimensions, end surface shapes and distances between the pre-generator 4 and the vortex generator 2, the circulation of the pre-generator 4 and the circulation of the vortex generator 2 are made to be in the same direction and synchronous.

[0041] A swirl chamber 5 is provided between the front generator 4 and the vortex generator 2. The front generator 4 converts the irrotational fluid into a swirling fluid and sends it into the swirl chamber 5. When the swirling fluid in the swirl chamber 5 passes through the vortex generator 2, the vortices generated by the front generator 4 and the vortex generator 2 are superimposed on each other, the circulation is increased, the lift generated by the vortex is increased, the vortex signal is stronger, clearer and more stable, and has higher linearity and better repeatability. Experimental verification shows that the vortex signal can be amplified by 2 to 10 times, and the loss of fluid pressure can be reduced. The vortices generated by the front generator 4 and the vortex generator 2 are superimposed on each other, so that the number of vortices is reduced, the operating frequency of the sensor is reduced, and the service life of the sensor 3 can be extended.

[0042] The front generator 4 and the vortex generator 2 are provided at the same time. During the test verification, it was found that the technical effect of reducing the vibration of the measuring tube 1 can be achieved, thereby improving the signal-to-noise ratio. The existing vortex flowmeter needs to be installed with a straight steady-flow pipe of not less than 80 cm in length before and after. The present invention does not need to install a steady-flow pipe and can meet the measurement requirements, which is more convenient to use.

[0043] The front generator 4 and the vortex generator 2 are both in the shape of right prisms, and the widths of the front generator 4 and the vortex generator 2 are the same; the bottom surface of the front generator 4 is in a rhombus shape, and the bottom surface of the front generator 4 is provided with a first diagonal line 41 and a second diagonal line 42, and the direction of the first diagonal line 41 is parallel to the axial direction of the measuring tube 1.

[0044] The angle range of the inner angle 43 of the bottom surface of the front shedder 4 is 85 degrees to 95 degrees. In this embodiment, the bottom surface of the front shedder 4 is square.

[0045] The bottom surface of the vortex generating body 2 is in the shape of an isosceles triangle. The bottom surface of the vortex generating body 2 is provided with a bottom side 21 and a waist 22. The bottom side 21 is provided at the rear end of the bottom surface of the vortex generating body 2. The direction of the bottom side 21 is parallel to the direction of the second diagonal line 42. The length of the bottom side 21 is equal to the length of the second diagonal line 42.

[0046] The length of the second diagonal line 42 determines the width of the front generator 4, and the length of the bottom side 21 determines the width of the vortex generator 2; if the length of the bottom side 21 is equal to the length of the second diagonal line 42, the widths of the front generator 4 and the vortex generator 2 can be ensured to be the same.

[0047] The length of the second diagonal line 42 is L, the shortest distance between the front shedder 4 and the vortex shedder 2 is S, and the ratio of L to S is in the range of 2.25 to 2.75.

[0048] The nominal diameter of the test tube 1 is DN, and the ratio of DN to L ranges from 3.9 to 4.17. In this embodiment, the ratio of DN to L is 4.

[0049] A display and a converter 6 are also provided. The converter 6 is provided between the sensor 3 and the display. The display is provided outside the measuring tube 1. The sensor 3 detects the number of vortices, and the converter 6 completes the signal conversion and transmits it to the display 6. The display 6 determines and displays the flow rate of the fluid according to the signal received from the converter 6.

[0050] Both ends of the measuring tube 1 are provided with flanges 11. Through the flanges 11, the measuring tube 1 can be conveniently installed on the pipeline to be tested.

[0051] In this embodiment, DN=25 mm, L=5.65 mm, S=2.5 mm; experimental verification shows that for a test tube with DN=25 mm, the length range of L is between 3 mm and 8 mm, and the length range of S is between 1 mm and 4 mm, both of which can meet the requirements for fluid flow measurement.

[0052] Example 2

[0053] In this embodiment, DN=32 mm, L=7.1 mm, S=3.5 mm; experimental verification shows that for a test tube with DN=32 mm, the length range of L is between 4 mm and 9 mm, and the length range of S is between 2 mm and 5 mm, both of which can meet the measurement requirements.

[0054] Example 3

[0055] In this embodiment, DN=40 mm, L=10 mm, S=4 mm; experimental verification shows that for a test tube with DN=40 mm, the length range of L is between 7 mm and 12 mm, and the length range of S is between 2 mm and 6 mm, both of which can meet the measurement requirements.

[0056] Among them, DN = 40 mm, L = 10 mm, S = 4 mm, the detected fluid medium is air, and the calibration records of the gas vortex flowmeter are as follows: its instrument coefficient K = 11.4018 / L, repeatability Er = 0.0564%, both of which can meet good test requirements.

[0057]

[0058] Example 4

[0059] In this embodiment, DN=50 mm, L=12 mm, S=5 mm; experimental verification shows that for a test tube with DN=50 mm, the length range of L is between 8 mm and 14 mm, and the length range of S is between 3 mm and 7 mm, both of which can meet the measurement requirements.

[0060] Among them, DN = 50 mm, L = 12 mm, S = 5 mm, the fluid medium tested is air, and the calibration record of the gas vortex flowmeter is as follows:

[0061]

[0062] Its instrument coefficient K=6.1277 / L and repeatability Er=0.4778%, both of which can meet good test requirements.

[0063] Example 5

[0064] In this embodiment, DN=65 mm, L=16.26 mm, S=6.5 mm; experimental verification shows that for a test tube with DN=65 mm, the length range of L is between 13 mm and 19 mm, and the length range of S is between 5 mm and 8 mm, both of which can meet the measurement requirements.

[0065] Example 6

[0066] In this embodiment, DN = 80 mm, L = 19.8 mm, S = 8 mm, the fluid medium detected is air, and the calibration record is as follows:

[0067]

[0068] It has been verified through experiments that for a test tube of DN=80 mm, the length range of L is between 17 mm and 22 mm, and the length range of S is between 6 mm and 10 mm, both of which can meet the measurement requirements.

[0069] Example 7

[0070] In this embodiment, DN = 100 mm, L = 24.75 mm, S = 10 mm, and the calibration records are as follows:

[0071]

[0072] It has been verified through experiments that for a test tube with DN=100 mm, the length range of L is between 21 mm and 27 mm, and the length range of S is between 8 mm and 12 mm, both of which can meet the measurement requirements.

[0073] Example 7

[0074] In this embodiment, DN = 125 mm, L = 31.1 mm, S = 12.5 mm, the fluid medium to be detected is air, and the calibration records are as follows:

[0075]

[0076] It has been verified through experiments that for a test tube of DN=125 mm, the length range of L is between 28 mm and 33 mm, and the length range of S is between 9 mm and 14 mm, both of which can meet the measurement requirements.

[0077] Example 8

[0078] In this embodiment, DN=150 mm, L=37.47 mm, S=15 mm; experimental verification shows that for a test tube with DN=150 mm, the length range of L is between 34 mm and 40 mm, and the length range of S is between 13 mm and 17 mm, both of which can meet the measurement requirements.

[0079] Example 9

[0080] In this embodiment, DN=200 mm, L=49.49 mm, S=20 mm; experimental verification shows that for a test tube with DN=200 mm, the length range of L is between 47 mm and 51 mm, and the length range of S is between 18 mm and 22 mm, both of which can meet the measurement requirements.

[0081] Example 10

[0082] In this embodiment, DN=250 mm, L=62.22 mm, S=25 mm; experimental verification shows that for a test tube with DN=250 mm, the length range of L is between 59 mm and 64 mm, and the length range of S is between 23 mm and 27 mm, both of which can meet the measurement requirements.

[0083] Embodiment 11

[0084] In this embodiment, DN=300 mm, L=74.84 mm, S=30 mm; experimental verification shows that for a test tube with DN=300 mm, the length range of L is between 72 mm and 77 mm, and the length range of S is between 28 mm and 32 mm, both of which can meet the measurement requirements.

[0085] Example 12

[0086] like Figure 8 As shown, in this embodiment, the implementation method of the vortex flowmeter is basically the same as that of Example 1, and the same parts are not repeated here. The difference is that the bottom surface of the vortex generating body 2 is in a "T" shape, which can achieve a similar test effect as that of Example 1.

[0087] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A vortex flowmeter, provided with a measuring tube, wherein a vortex generator and a sensor are provided in the measuring tube, wherein the vortex generator is provided directly behind the sensor, and wherein: A front generator is also arranged in the test tube. The front generator is arranged directly behind the vortex generator. The circulation of the front generator is in the same direction and synchronous with the circulation of the vortex generator. A vortex chamber is arranged between the front generator and the vortex generator.

2. The vortex flowmeter according to claim 1, characterized in that: The front generator and the vortex generator are both in the shape of right prisms, and have the same width; the bottom surface of the front generator is in the shape of a rhombus, and the bottom surface of the front generator is provided with a first diagonal line and a second diagonal line, and the direction of the first diagonal line is parallel to the axial direction of the measuring tube.

3. The vortex flowmeter according to claim 2, characterized in that: The inner angle of the bottom surface of the front shedder is in the range of 85 degrees to 95 degrees.

4. The vortex flowmeter according to claim 3, characterized in that: The bottom surface of the front generating body is in a square shape.

5. The vortex flowmeter according to any one of claims 2 to 4, characterized in that: The bottom surface of the vortex generator is in an isosceles triangle shape or a "T" shape, and a bottom edge is provided at the rear end of the bottom surface of the vortex generator. The direction of the bottom edge is parallel to the direction of the second diagonal line, and the length of the bottom edge is equal to the length of the second diagonal line.

6. The vortex flowmeter according to claim 5, characterized in that: The length of the second diagonal line is L, the shortest distance between the front generator and the vortex generator is S, and the ratio of L to S ranges from 2.25 to 2.

75.

7. The vortex flowmeter according to claim 6, characterized in that: The nominal diameter of the test tube is DN, and the ratio of DN to L ranges from 3.9 to 4.

17.

8. The vortex flowmeter according to claim 7, characterized in that: The ratio of DN to L is 4.

9. The vortex flowmeter according to any one of claims 1 to 4, characterized in that: A display instrument and a converter are also provided. The converter is arranged between the sensor and the display instrument. The display instrument is arranged outside the measuring tube.

10. The vortex flowmeter according to any one of claims 1 to 4, characterized in that: Both ends of the measuring tube are provided with flanges.

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