Thermally compensated vortex flowmeter

Abstract

The application discloses a temperature and pressure compensation vortex flowmeter and relates to the technical field of flowmeters.The application comprises coaxially connected generation pipeline, detection pipeline and auxiliary measurement pipeline.A vortex generation body composed of multiple layers of trapezoidal columns is arranged in the generation pipeline to generate composite vortexes and provide multi-frequency flow information.A plurality of resonant cavity arrays with different sizes and shapes are arranged on the inner wall of the detection pipeline, and the self-compensation of flow, temperature and pressure is realized by using the acoustic frequency spectrum, and no additional sensor is needed.A detection wire and a first MEMS microphone are arranged in the auxiliary measurement pipeline as a supplementary detection means.The multiple sealing design ensures the stability of the measurement environment.The application improves the measurement precision, stability and reliability by means of the composite vortex, multi-cavity cooperation and physical characteristic decoupling, and simultaneously simplifies the system structure, reduces the cost and maintenance difficulty.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flow meters, in particular to a temperature and pressure compensation vortex flow meter. BACKGROUND

[0002] Vortex flow meters are widely used in fluid flow measurement due to their simple structure, lack of movable parts, and low pressure loss. The basic principle is to set a vortex generator in the pipeline, which generates a Karman vortex when the fluid flows through, and the flow rate is calculated by detecting the vortex frequency. However, the existing technology has the following shortcomings: single frequency vortex information is limited The vortex generator of the traditional vortex flow meter is of a single shape, which only generates a single frequency vortex, and the flow information is relatively single. In the case of multiphase flow or complex fluid conditions, it is difficult to accurately reflect the flow state, which limits the measurement accuracy. Temperature and pressure compensation requires additional sensors, and the system is complex. The temperature and pressure of the fluid significantly affect the flow measurement, and the traditional technology relies on additional temperature and pressure sensors for compensation. This increases the complexity, cost and risk of failure of the system, and maintenance is more cumbersome. SUMMARY

[0003] To overcome the above-mentioned defects of the prior art, the present application provides the following technical solution: a temperature and pressure compensation vortex flow meter, comprising a coaxially fixed and connected generation pipeline, a detection pipeline and an auxiliary measurement pipeline, the outer side of the detection pipeline is provided with a separation collar, and the separation collar and the outer surfaces of the generation pipeline, the detection pipeline and the auxiliary measurement pipeline form a negative pressure sealed space; a vortex generator is fixedly installed in the radial direction inside the generation pipeline through a vortex generator support, wherein the vortex generator is composed of a plurality of stacked trapezoidal cylinders, and the multiple layers of trapezoidal cylinders are used to generate different sizes and intensities of vortices for fluids of different heights, forming composite vortices for containing more flow information; further comprising a plurality of resonant cavities arranged in a circular equidistant array on the inner wall of the detection pipeline, each resonant cavity is a cylindrical or conical hollow, and the diameter, depth and shape of each resonant cavity are different. Small diameter shallow cavity: more sensitive to flow rate (vortex frequency) because it is more easily excited by high-frequency pressure waves; large diameter deep cavity: more sensitive to temperature because temperature changes will significantly affect the propagation of low-frequency sound waves; medium size cavity: more sensitive to pressure because the effects of pressure on fluid density and compressibility are more pronounced in the medium frequency range.

[0004] Preferably, a plurality of detection wires are arranged along the radial direction of the auxiliary measurement pipeline, the length direction of the detection wires is parallel to the stacking direction of the vortex generator, one end of the detection wires is fixedly connected with the inside of the auxiliary measurement pipeline, the other end of the detection wires extends to the outside of the auxiliary measurement pipeline, and the other end of the detection wires is fixed on a detection wire tensioning frame, and the detection wire tensioning frame is fixed on the outer surface of the auxiliary measurement pipeline.

[0005] Preferably, a rectangular through hole is arranged at the joint of the detection wire and the auxiliary measuring pipeline, a sealing block is fixedly arranged in the rectangular through hole, a cylindrical through hole is arranged at the joint of the detection wire and the sealing block, and a detection wire sealing rubber sleeve is fixedly and sealingly arranged in the cylindrical through hole. The detection wire sealing rubber sleeve is sleeved on the detection wire, so that an elastic seal is formed between the detection wire and the sealing block.

[0006] Preferably, the part of the detection wire located outside the auxiliary measuring pipeline is fixedly installed with a fluctuation transmission wire along the radial direction of the detection wire. An end of the fluctuation transmission wire away from the detection wire is fixedly installed on the shell of the first MEMS microphone. The first MEMS microphone is fixedly installed on the first MEMS microphone mounting plate. The first MEMS microphone mounting plate and the detection wire tensioning frame are fixedly integrated through the connecting beam rod. It should be noted that the detection wire and the fluctuation transmission wire are both in a straight and tight state.

[0007] Preferably, a sealing chamber is arranged on the outer side of the detection wire tensioning frame and the first MEMS microphone mounting plate, and the sealing chamber is fixedly and sealingly arranged on the outer surface of the auxiliary measuring pipeline.

[0008] Preferably, an indicating arrow is arranged on the outer surface of the generation pipeline, and the right direction of the indicating arrow is the movement direction of the fluid.

[0009] Preferably, the opposite ends of the generation pipeline and the auxiliary measuring pipeline are fixedly installed with mounting flanges.

[0010] Preferably, a second MEMS microphone mounting plate is fixedly and sealingly arranged at one end of each resonant cavity located outside the detection pipeline, and a second MEMS microphone is fixedly installed on the second MEMS microphone mounting plate.

[0011] Compared with the prior art, the present application has the following advantages: (1) The vortex generator of the present application is composed of multiple trapezoidal cylinders stacked layer by layer, which can generate vortices of different sizes and intensities at different heights, forming composite vortices. This design makes the vortex frequency contain more flow information, similar to multiple tones in an audio spectrum, which is more abundant than traditional single-frequency vortices. By detecting the frequency of these composite vortices, not only can the flow be measured more accurately, but also more comprehensive data support is provided for subsequent temperature and pressure compensation. This multi-frequency feature enables the system to more realistically reflect the fluid flow state, significantly improving measurement accuracy and reliability; (2) The detection pipe inner wall of the present application is provided with multiple resonant cavities of different diameters, depths and shapes, arranged in a circular equidistant array. Small diameter shallow cavities are sensitive to flow rate, large diameter deep cavities are sensitive to temperature, and medium size cavities are sensitive to pressure. This differentiated design enables the resonant cavities to naturally separate the effects of flow, temperature and pressure through the frequency spectrum of sound waves, achieving self-compensation function without additional temperature and pressure sensors. This not only reduces system cost and maintenance difficulty, but also simplifies the structure, improves the overall practicality and economy; (3) The resonant cavities of the present application have different response sensitivities to flow, temperature and pressure through different sizes and shapes, forming a filter-like effect. Multiple cavities working together can extract independent information from mixed sound wave signals, avoiding complex electronic calculations and directly completing temperature and pressure compensation through hardware. This physical decoupling method ensures that the measurement results remain stable under complex working conditions; (4) The auxiliary measurement pipe of the present application is provided with a detection wire, which transmits the fluctuation signals caused by vortices to the first MEMS microphone through the fluctuation transmission wire. This auxiliary detection system provides a backup means for flow measurement, especially when the main system fails, it can be used as an emergency or reference. Although the complex shape of the vortex generator may introduce some errors, this design enhances the robustness of the system, ensuring the continuity and reliability of the measurement process. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is an external structure diagram of the present application.

[0013] Figure 2 It is a separate sleeve ring structure diagram of the present application.

[0014] Figure 3 It is a vortex generator structure diagram of the present application.

[0015] Figure 4 It is a detection pipe structure diagram of the present application.

[0016] Figure 5 It is a detection pipe structure diagram of the present application. Figure 4 It is a structure diagram of A in the present application.

[0017] Figure 6 It is a resonant cavity structure diagram of the present application.

[0018] In the figure: 101 - generating pipe; 102 - mounting flange; 103 - separation collar; 104 - indicating arrow; 105 - auxiliary measuring pipe; 106 - detecting pipe; 107 - sealing chamber; 108 - sealing block; 109 - detecting wire; 110 - detecting wire tensioning frame; 111 - first MEMS microphone mounting plate; 112 - connecting beam rod; 113 - first MEMS microphone; 114 - fluctuation transmission wire; 115 - detecting wire sealing rubber sleeve; 116 - resonant cavity; 117 - second MEMS microphone mounting plate; 118 - second MEMS microphone; 119 - vortex generating body; 120 - vortex generating body support. DETAILED DESCRIPTION

[0019] The technical solutions of the present application are further illustrated below in conjunction with the accompanying drawings. Figures 1-6 The technical solutions of the present application are further illustrated below in conjunction with the accompanying drawings.

[0020] The application provides a temperature and pressure compensation vortex flowmeter, which comprises coaxially fixedly connected generation pipeline 101, detection pipeline 106 and auxiliary measurement pipeline 105, the outer side of the detection pipeline 106 is provided with a separation collar 103, the separation collar 103 and the outer surfaces of the generation pipeline 101, the detection pipeline 106 and the auxiliary measurement pipeline 105 form a negative pressure closed space, a vortex generator 119 is fixedly installed on the generation pipeline 101 in the radial direction by a vortex generator support 120, the vortex generator 119 is composed of multiple trapezoidal column bodies stacked layer by layer, the multiple trapezoidal column bodies are used for generating vortexes with different sizes and intensities for fluid with different heights, forming composite vortexes for containing more flow information, and a plurality of resonant cavities 116 arranged in a circular equidistant array are arranged on the inner wall of the detection pipeline 106, each resonant cavity 116 is a cylindrical or conical hollow, and the diameter, depth and shape of each resonant cavity 116 are different. Small diameter shallow cavities: more sensitive to flow rate (vortex frequency) because it is more easily excited by high-frequency pressure waves; large diameter deep cavities: more sensitive to temperature because temperature changes significantly affect the propagation of low-frequency sound waves; medium-sized cavities: more sensitive to pressure because the effects of pressure on fluid density and compressibility are more obvious in the medium frequency range. A plurality of detection wires 109 are arranged along the radial direction of the auxiliary measurement pipeline 105, the length direction of the detection wire 109 is parallel to the stacking direction of the vortex generator 119, one end of the detection wire 109 is fixedly connected with the inside of the auxiliary measurement pipeline 105, the other end of the detection wire 109 extends to the outside of the auxiliary measurement pipeline 105, and the other end of the detection wire 109 is fixed on a detection wire tensioning frame 110, the detection wire tensioning frame 110 is fixed on the outer surface of the auxiliary measurement pipeline 105. A rectangular through hole is arranged at the joint of the detection wire 109 and the auxiliary measurement pipeline 105, a sealing block 108 is fixedly arranged in the rectangular through hole, a cylindrical through hole is arranged at the joint of the detection wire 109 and the sealing block 108, a detection wire sealing rubber sleeve 115 is fixedly arranged in the cylindrical through hole, the detection wire sealing rubber sleeve 115 is sleeved on the detection wire 109, so that an elastic seal is formed between the detection wire 109 and the sealing block 108. The part of the detection wire 109 located outside the auxiliary measurement pipeline 105 is fixedly installed with a wave transmission wire 114 along the radial direction of the detection wire 109, one end of the wave transmission wire 114 away from the detection wire 109 is fixedly installed on the shell of a first MEMS microphone 113, the first MEMS microphone 113 is fixedly installed on a first MEMS microphone mounting plate 111, and the first MEMS microphone mounting plate 111 and the detection wire tensioning frame 110 are fixedly connected by a connecting beam 112. It should be noted that the detection wire 109 and the wave transmission wire 114 are in a straight and tight state. The outer sides of the detection wire tensioning frame 110 and the first MEMS microphone mounting plate 111 are provided with a sealing chamber 107, and the sealing chamber 107 is fixedly sealed on the outer surface of the auxiliary measurement pipeline 105.The outer surface of the generation pipeline 101 is provided with an indication arrow 104, and the right direction of the indication arrow 104 is the movement direction of the fluid. The opposite ends of the generation pipeline 101 and the auxiliary measurement pipeline 105 are fixedly installed with mounting flanges 102. Each resonant cavity 116 is fixedly sealed with a second MEMS microphone mounting plate 117 at one end outside the detection pipeline 106, and the second MEMS microphone mounting plate 117 is fixedly installed with a second MEMS microphone 118.

[0021] The working principle of the temperature and pressure compensation vortex flowmeter disclosed in the application is as follows: the whole is arranged in series in the pipeline, so that the right-hand direction indicated by the indication arrow 104 is the movement direction of the fluid, when installed, the axis of the pipeline 101 is arranged as horizontally as possible, and the direction locked by the indication arrow 104 is vertically upward. When the fluid passes through the vortex generator 119, composite vortices are formed behind the vortex generator 119 (in the direction of the fluid flowing through the vortex generator 119), and the vortices have a specific frequency and contain more information (similar to an audio spectrum, multiple tones) than a traditional single frequency. When the fluid flows through the vortex generator 119, the wide ladder-shaped bottom layer generates large vortices, and the narrow ladder-shaped upper layer generates small vortices. These vortices propagate downstream like waves, providing a basis for subsequent measurement. The flow rate is detected by detecting the frequency of the vortices. The pressure wave generated by the vortices enters the resonance cavity 116, and the resonance cavity 116 emits sound waves. The frequency of these sound waves is not only related to the flow rate, but also naturally contains information about the temperature and pressure. No additional temperature and pressure sensors are needed, and the resonance cavity 116 itself completes the compensation. The frequency of the sound waves emitted by the resonance cavity 116 is triggered by the pressure wave when the fluid passes through, and this frequency is affected by the following three physical quantities: flow rate (flow speed): the flow speed determines the generation frequency of the vortices (Kármán vortex street principle), and the vortex frequency directly affects the frequency of the pressure wave, which in turn drives the resonance of the resonance cavity 116; temperature: temperature changes the density and sound speed of the fluid, affecting the propagation characteristics of the sound waves in the resonance cavity 116; pressure: pressure changes the density and compressibility of the fluid, which also affects the frequency of the sound waves in the resonance cavity 116. On the surface, the frequency of the sound waves output by the resonance cavity 116 is a mixed signal containing the superposition effect of the three. However, the ingenious part of the design is that through the cooperative work of multiple cavities and the decoupling of physical characteristics, independent information can be extracted from this signal without additional temperature and pressure sensors. Specifically, the sensitivity of different resonance cavities 116 is divided: the resonance cavity 116 array is not completely the same, but is intentionally designed to be different in size and shape (such as diameter and depth). Each resonance cavity 116 has different response sensitivity to flow rate, temperature and pressure. For example: small diameter shallow cavity: more sensitive to flow rate (vortex frequency), because it is more easily excited by high-frequency pressure waves. Large diameter deep cavity: more sensitive to temperature, because temperature changes will significantly affect the propagation of low-frequency sound waves. Medium-sized cavity: more sensitive to pressure, because the effect of pressure on fluid density and compressibility is more obvious in the medium frequency range. This differentiated design is like a filter, allowing the sound wave frequency of each resonance cavity 116 to tend to reflect a certain dominant factor (where the multiple layer-by-layer ladder-shaped column bodies of the vortex generator 119 correspond to the same as above, all generate corresponding sound waves in a certain resonance cavity 116, and the frequency of the sound waves is judged). Assuming that there are 10 resonance cavities 116, each resonance cavity 116 emits a unique sound wave frequency (passive).Instead of a single frequency, a frequency spectrum (like a light spectrum) is obtained, containing several frequency components. By analyzing this frequency spectrum, the effects of flow rate, temperature and pressure can be separated and compensated for.

[0022] The flow rate is linearly related to the vortex frequency (i.e. the pressure wave frequency), f = St · v / d (where (f) is the vortex frequency, (St) is the Strouhal number, (v) is the flow rate, and (d) is the diameter of the orifice); the acoustic frequency of the resonant cavity 116 follows the vortex frequency, so the high frequency part of the frequency spectrum mainly reflects the flow rate.

[0023] Temperature changes the speed of sound (c) of the fluid, which is given by the formula: c = VRT / M (where (V) is the specific heat ratio, (R) is the gas constant, (T) is the temperature, and (M) is the molar mass); when the speed of sound increases, the acoustic frequency in the resonant cavity 116 will shift as a whole, especially in the low frequency cavity. This "frequency drift" can be used to calculate the temperature.

[0024] Pressure changes the density (p) of the fluid, which is related to the pressure by the formula: p = PM / RT (where (P) is the pressure); density changes affect the wavelength and intensity of the acoustic wave, especially for the medium frequency resonant cavity 116. By analyzing the amplitude changes of certain specific peaks in the frequency spectrum, the pressure can be calculated.

[0025] Assumptions: the fluid is air, and there are three resonant cavities 116 in the pipe: cavity 1 (small shallow cavity): frequency 1000 Hz, mainly reflecting a flow rate of 10 m / s; cavity 2 (medium cavity): frequency 500 Hz, intensity enhanced, reflecting a pressure of 2 bar; cavity 3 (large deep cavity): frequency 200 Hz, shifted to 220 Hz, reflecting a temperature rise from 20°C to 30°C. The information of the resonant cavity 116 is not single, but reflected by the frequency spectrum of multiple resonant cavities 116. The different sensitivities of different resonant cavities 116 to flow rate, temperature and pressure make it possible to decouple these three variables from the frequency spectrum. This completely relies on physical properties, avoids electronic calculation, and directly uses hardware structure to complete temperature and pressure compensation.

[0026] In addition, in order to ensure stability, when the vortex passes through the detection wire 109, the detection wire 109 will also produce a corresponding fluctuation, which will be transmitted to the fluctuation transmission wire 114, and then transmitted to the first MEMS microphone 113 through the fluctuation transmission wire 114, so that the first MEMS microphone 113 can detect the fluctuation frequency of the detection wire 109, so as to determine the frequency of the vortex, and further determine the flow rate (due to the shape of the vortex orifice 119, this method has errors, but it is a supplementary detection device, for emergency or reference).

Claims

1. A temperature and pressure compensated vortex flowmeter characterized by: The application relates to a vortex flowmeter, which comprises a generation pipeline (101), a detection pipeline (106) and an auxiliary measurement pipeline (105) coaxially fixedly communicated, the outer side of the detection pipeline (106) is provided with a separation sleeve ring (103), the separation sleeve ring (103) and the outer surfaces of the generation pipeline (101), the detection pipeline (106) and the auxiliary measurement pipeline (105) form a negative pressure closed space. A vortex generator (119) is fixedly installed in the radial direction of the generation pipeline (101) through a vortex generator support (120), wherein the vortex generator (119) is composed of a plurality of stacked trapezoidal columns, the multiple trapezoidal columns are used for generating vortexes with different sizes and strengths for fluids of different heights to form composite vortexes for containing more flow information. The vortex flowmeter further comprises a plurality of resonant cavities (116) arranged in a circular equidistant array on the inner wall of the detection pipeline (106), each resonant cavity (116) is a cylindrical or conical hollow, and the diameter, depth and shape of each resonant cavity (116) are different, and different resonant cavities (116) have different sensitivities to flow, temperature and pressure. The sound wave frequency emitted by the resonant cavity (116) is triggered by the pressure wave of the fluid passing through, and the frequency is affected by the three physical quantities of flow rate, temperature and pressure; the sound wave frequency output by the resonant cavity (116) is a mixed signal containing the superposition effect of the three, and independent information is extracted from the signal through the cooperative work of multiple cavities and the decoupling of physical characteristics.

2. A temperature and pressure compensated vortex flowmeter according to claim 1 wherein: A plurality of detection filaments (109) are arranged along the radial direction of the auxiliary measurement pipeline (105), the length direction of the detection filaments (109) is parallel to the stacking direction of the vortex generator (119), one end of the detection filaments (109) is fixedly matched with the inside of the auxiliary measurement pipeline (105), the other end of the detection filaments (109) extends to the outside of the auxiliary measurement pipeline (105), and the other end of the detection filaments (109) is fixed on a detection filament tensioning frame (110) fixed on the outer surface of the auxiliary measurement pipeline (105).

3. A temperature and pressure compensated vortex flowmeter according to claim 2 wherein: A rectangular through hole is arranged at the joint of the detection filament (109) and the auxiliary measurement pipeline (105), a sealing block (108) is sealingly fixed in the rectangular through hole, a cylindrical through hole is arranged at the joint of the sealing block (108) and the detection filament (109), and a detection filament sealing rubber sleeve (115) is sealingly arranged in the cylindrical through hole, the detection filament sealing rubber sleeve (115) is sleeved on the detection filament (109), so that an elastic seal is formed between the detection filament (109) and the sealing block (108).

4. A temperature and pressure compensated vortex flowmeter according to claim 3 wherein: The part of the detection wire (109) located outside the auxiliary measurement pipeline (105) is fixedly installed with a wave transmission wire (114) along its radial direction, the end of the wave transmission wire (114) away from the detection wire (109) is fixedly installed on the shell of the first MEMS microphone (113), the first MEMS microphone (113) is fixedly installed on the first MEMS microphone mounting plate (111), and the first MEMS microphone mounting plate (111) is fixedly integrated with the detection wire tensioning frame (110) through the connecting beam rod (112).

5. A temperature and pressure compensated vortex flowmeter according to claim 4 wherein: The outer side of the detection wire tensioning frame (110) and the first MEMS microphone mounting plate (111) is provided with a sealed chamber (107), and the sealed chamber (107) is fixedly sealed on the outer surface of the auxiliary measurement pipeline (105).

6. A temperature and pressure compensated vortex flowmeter according to claim 5 wherein: The outer surface of the generation pipeline (101) is provided with an indicating arrow (104), and the right direction of the indicating arrow (104) is the movement direction of the fluid.

7. A temperature and pressure compensated vortex flowmeter according to claim 6 wherein: The opposite ends of the generation pipeline (101) and the auxiliary measurement pipeline (105) are fixedly installed with mounting flanges (102).

8. A temperature and pressure compensated vortex flowmeter according to claim 7 wherein: The end of each resonant cavity (116) located outside the detection pipeline (106) is fixedly sealed with a second MEMS microphone mounting plate (117), and the second MEMS microphone mounting plate (117) is fixedly installed with a second MEMS microphone (118).

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