Novel gas-liquid two-phase moisture flow meter with double-cavity structure

Abstract

The invention discloses a novel gas-liquid two-phase moisture flow meter with a double-cavity structure, and belongs to the technical field of flow meters, the novel gas-liquid two-phase moisture flow meter comprises a measuring tube system and a venturi tube double-frequency measuring system.The novel gas-liquid two-phase moisture flow meter integrates a kinetic energy reduction unit and a double-frequency metering unit, the preceding stage is of a two-stage structure of a conical pore plate and a cone, and the two-stage structure of the venturi tube is achieved; stable gas-liquid pre-separation and flow field layering are realized without movable parts; the upper probe and the lower probe in the Venturi tube at the rear end synchronously capture vortex frequency differences generated by media with different liquid contents, the gas-phase flow, the liquid-phase flow and the liquid contents are directly calculated through dynamic temperature and pressure compensation and spectrum analysis in combination with integrated temperature sensing and pressure measurement, the gas flow measuring range ratio and the low-speed measuring capacity are greatly improved through the design, and the measurement accuracy is greatly improved. And through differential pressure monitoring, multi-signal cross validation and a self-diagnosis early warning mechanism, the reliability and intrinsic safety of the system are remarkably enhanced while high precision and wide adaptability are ensured.

Description

Technical Field

[0001] This invention relates to the field of flow meter technology, and in particular to a novel dual-chamber structure gas-liquid two-phase wet gas flow meter. Background Technology

[0002] With increasingly stringent standards for green and energy-saving production and refined management, especially in the industrial and natural gas extraction sectors, higher requirements are being placed on the accurate measurement of gas-liquid two-phase mixed media. However, existing gas-liquid two-phase flow measurement technologies still have many limitations and cannot meet the current on-site measurement needs for high efficiency, high precision, and high safety.

[0003] Currently, common methods for measuring gas-liquid two-phase flow mainly include the following categories: First, systems combining traditional gas-liquid separators and flow meters, which are bulky and cumbersome, involve pressure vessel safety supervision, have limited functionality, and incur high compliance costs; Second, differential pressure measurement methods based on the Venturi structure, which indirectly calculate liquid content through multiple differential pressure transmitters, but due to the complex gas-liquid mixing flow field and the low range ratio of differential pressure instruments (generally not exceeding 10:1), the measurement range is narrow and the error is significant; Third, adding a radiation source for compensation to the Venturi structure can improve accuracy to some extent, but the radiation source itself poses safety risks and does not fundamentally solve the range ratio limitation, making it difficult to promote; Fourth, adding a water content analyzer after the flow meter, however, such instruments have insufficient measurement accuracy for low liquid content in gas environments, and their practical application effect is limited; In addition, although mass flow meters are suitable for single-phase gas measurement, the error increases sharply in gas-liquid mixing conditions, and their measuring tube walls are thin, making it difficult to cope with complex working conditions such as high pressure and multiple particulate matter.

[0004] In summary, existing gas-liquid two-phase flow metering technologies generally suffer from insufficient accuracy, narrow measurement range, low safety, poor adaptability, or high maintenance requirements, and are gradually failing to meet the urgent needs of modern industry for efficient, reliable, and safe metering. Summary of the Invention

[0005] This invention provides a novel dual-cavity gas-liquid two-phase wet gas flow meter, which can solve the problems of insufficient measurement accuracy, narrow measurement range, safety risks, complex and large system size and difficult maintenance in the prior art.

[0006] A novel dual-cavity gas-liquid two-phase wet gas flow meter includes: a measuring tube system and a Venturi tube dual-frequency measuring system. The measuring tube system is used for preliminary kinetic energy reduction and separation of the gas-liquid mixture to form stratified flow of the gas-liquid mixture with different liquid contents. The Venturi tube dual-frequency measuring system is connected to the rear end of the measuring tube system and is used to receive the stratified gas-liquid mixture. The Venturi tube dual-frequency measuring system includes a Venturi tube, a pressure measuring component, a frequency signal generation and acquisition component, and a signal processing component. The Venturi tube is fitted with a... The system includes a generator for inducing vortices in a gas-liquid mixture; a pressure measurement component for measuring the medium pressure; and a frequency signal generation and acquisition component comprising an upper frequency probe and a lower frequency probe inserted from the upper and lower parts of a venturi tube and located behind the generator, respectively, for acquiring high-frequency signals generated by the upper low-liquid-content gas-liquid mixture vortex and low-frequency signals generated by the lower high-liquid-content gas-liquid mixture vortex, respectively. The signal processing component receives the pressure signal and the upper and lower frequency signals, and analyzes the liquid content through spectral comparison to calculate the gas flow rate and liquid flow rate.

[0007] Preferably, the measuring tube system includes a measuring tube, a tapered orifice plate and a cone installed inside the measuring tube, and an inlet flange connected to the inlet end of the measuring tube. The tapered orifice plate is installed in the middle of the measuring tube to form a first chamber. The cone is installed in the measuring tube behind the tapered orifice plate by a cone fixing bracket to form a second chamber. The measuring tube system has an outlet flange installed at the rear end.

[0008] Preferably, it also includes a differential pressure measurement and monitoring component, which includes pressure tapping holes opened on the walls of measuring tubes on both sides of the conical orifice plate, differential pressure tapping pipes installed on the pressure tapping holes, and a differential pressure transmitter connected to the differential pressure tapping pipes via a valve group. The differential pressure transmitter is connected to the signal processing component via a differential pressure transmitter and converter connecting pipe.

[0009] Preferably, the frequency signal generation and acquisition component further includes an upper mounting structure for mounting and sealing the upper frequency probe, and a lower mounting structure for mounting and sealing the lower frequency probe. The upper mounting structure includes an upper base installed on the upper part of the venturi tube, an upper sealing gasket set in the groove of the upper base, and an upper pressure cover. The upper pressure cover is fastened to the upper base by upper pressure cover fixing screws to press and seal the upper sealing gasket and the upper frequency probe. The lower mounting structure includes a lower base installed at the bottom of the venturi tube, a lower sealing gasket disposed in the groove of the lower base, and a lower pressure cover. The lower pressure cover is fastened to the lower base by a lower pressure cover fixing screw to press and seal the lower sealing gasket and the lower frequency probe.

[0010] Preferably, the lower mounting structure further includes a lower cover for protecting the external connection of the lower frequency probe, the lower cover being mounted on the lower base by lower cover base fixing screws.

[0011] Preferably, the upper frequency probe is connected to the signal processing component via a vertical connecting rod, the connecting rod is connected to the upper base via a connecting rod base fixing screw, and the lower frequency probe is connected to the signal processing component via a lower cover and a connecting rod connecting tube.

[0012] Preferably, the pressure measurement assembly includes a pressure tapping tube located at the front of the venturi tube and a pressure transmitter connected to the pressure tapping tube. The pressure transmitter is connected to the signal processing assembly via a pressure transmitter-to-converter connection tube.

[0013] Preferably, the signal processing component is a converter.

[0014] Preferably, both the upper frequency probe and the lower frequency probe are equipped with temperature sensors.

[0015] Preferably, the front and rear ends of the venturi tube dual-frequency measurement system are respectively provided with a venturi tube inlet flange and an outlet flange, and the measuring tube outlet flange of the measuring tube system is connected to the venturi tube inlet flange by fasteners and gaskets.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This scheme achieves high-precision measurement of gas-liquid two-phase media through the collaborative design of integrated dual-cavity structure measuring tube and Venturi tube dual-frequency measurement system. Its core innovation lies in the fact that the front-end dual-cavity structure is connected in series with a conical orifice plate and a cone, and the flow field stratification preprocessing can be completed without moving parts. The back end uses upper and lower dual-frequency probes to independently measure and perform spectrum reference calculation on the stratified media, and combined with dynamic temperature and pressure compensation, it not only improves the gas flow range ratio, but also significantly improves the measurement accuracy of gas phase, liquid phase flow and liquid content.

[0017] (2) The system has no moving parts inside, and the structure is robust and compact, enabling long-term maintenance-free operation. The differential pressure measurement using the conical orifice plate realizes the dual functions of flow reference and safety monitoring. Combined with pressure and temperature monitoring and multi-signal cross-verification, a complete self-diagnosis mechanism including anti-clogging and abnormal operating condition early warning is constructed, which fully ensures the safety of the metering process and the reliable operation of the system.

[0018] (3) This solution has good performance in measuring low-speed airflow and is suitable for a wide range of scenarios. The integrated design solves the problem of moisture measurement. While improving measurement efficiency, it reduces instrument investment and maintenance costs, and reduces the labor intensity and safety risks of personnel. It has broad application prospects. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the front structure of the flow meter provided by the present invention; Figure 2 This is a schematic cross-sectional view of the internal structure of the flow meter provided by the present invention; Figure 3 A schematic diagram of the Venturi tube structure provided by the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. Imported flange; 2. Measuring tube; 3. Differential pressure tapping tube; 4. Valve assembly; 5. Differential pressure transmitter; 6. Connecting pipe between differential pressure transmitter and converter; 7. Measuring tube outlet flange; 8. Sealing gasket; 9. Venturi tube inlet flange; 10. Fasteners; 11. Venturi tube; 12. Pressure tapping tube; 13. Pressure transmitter; 14. Connecting pipe between pressure transmitter and converter; 15. Converter; 16. Upper base; 17. Connecting rod base fixing screws; 18. 19. Connecting rod; 20. Lower base; 21. Lower cover base fixing screw; 22. Lower cover; 23. Connecting pipe between lower cover and connecting rod; 24. Outlet flange; 25. Conical orifice plate; 26. Cone; 27. Cone fixing bracket; 28. Upper sealing gasket; 29. ​​Upper frequency probe; 30. Upper pressure cap fixing screw; 31. Upper pressure cap; 32. Lower sealing gasket; 33. Lower frequency probe; 34. Lower pressure cap fixing screw; 35. Generator. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0022] like Figures 1 to 3As shown in the figure, an embodiment of the present invention provides a novel dual-cavity gas-liquid two-phase wet gas flow meter, comprising: a measuring tube system and a Venturi tube dual-frequency measuring system. The measuring tube system is used for preliminary kinetic energy reduction and separation of the gas-liquid mixture to form stratified flow of the gas-liquid mixture with different liquid contents. The Venturi tube dual-frequency measuring system is connected to the rear end of the measuring tube system and is used to receive the stratified gas-liquid mixture. The Venturi tube dual-frequency measuring system includes a Venturi tube 11, a pressure measuring component, a frequency signal generation and acquisition component, and a signal processing component. The inlet of the throat of the Venturi tube 11 is... The device is equipped with a generator 35 for generating vortices in a gas-liquid mixture; a pressure measurement component for measuring the pressure of the medium; and a frequency signal generation and acquisition component including an upper frequency probe 28 and a lower frequency probe 32 inserted from the upper and lower parts of the venturi tube 11 and located behind the generator 35, respectively, for acquiring the high-frequency signal generated by the upper low-liquid-content gas-liquid mixture vortex and the low-frequency signal generated by the lower high-liquid-content gas-liquid mixture vortex, respectively; and a signal processing component for receiving the pressure signal and the upper and lower frequency signals, and for analyzing the liquid content through spectral comparison, thereby calculating the gas flow rate and the liquid flow rate.

[0023] The measuring tube system includes a measuring tube 2, a tapered orifice plate 24 and a cone 25 installed inside the measuring tube 2, and an inlet flange 1 connected to the inlet end of the measuring tube 2. The tapered orifice plate 24 is installed in the middle of the measuring tube 2 to form a first chamber. The cone 25 is installed in the measuring tube 2 behind the tapered orifice plate 24 through a cone fixing bracket 26 to form a second chamber. A measuring tube outlet flange 7 is installed at the rear end of the measuring tube system.

[0024] The measuring tube system is a key functional unit for the flow meter to achieve kinetic energy reduction and pre-stratification of the gas-liquid two-phase medium. Its main body is a measuring tube 2, with an inlet flange 1 and a measuring tube outlet flange 7 connected at the inlet and outlet ends of the pipe, respectively, to achieve a reliable connection with the process pipeline.

[0025] Its core design lies in two functional structures arranged sequentially inside the measuring tube 2: First, the tapered orifice plate 24 fixedly installed in the middle of the measuring tube 2 and its upstream and downstream pipe sections constitute the first chamber.

[0026] When the gas-liquid mixture flows through this point, the flow cross-section suddenly contracts, generating a strong throttling effect. A portion of the pressure energy, i.e., the kinetic energy, of the medium is rapidly consumed here. Due to the order-of-magnitude difference in density between the gas and the liquid, under the same flow disturbance, the liquid phase medium, which has a higher density and stronger inertia, is more likely to change its motion state, thus beginning to show an initial separation tendency from the gas phase medium.

[0027] Next, downstream of the conical orifice plate 24, a cone 25 is installed inside the measuring tube 2 via a cone fixing bracket 26. The cone 25 and the surrounding flow channel structure constitute the second chamber.

[0028] The function of the cone 25 is to dissipate energy and rectify the flow field of the medium that has already undergone preliminary kinetic energy reduction. When the medium flows around the cone 25, the flow channel is guided to undergo gentle expansion and adjustment, further reducing the flow velocity and stabilizing the flow state.

[0029] This process enhances density-based separation, ultimately leading to a relatively stable liquid content gradient distribution along the pipe cross-section before the mixed medium flows out of the component: that is, the gas-liquid mixture with lower liquid content and lower density tends to flow in the upper part of the pipe; while the gas-liquid mixture with higher liquid content and higher density converges in the middle and lower part of the pipe.

[0030] The dual-chamber design, in which the conical orifice plate 24 and the cone 25 are connected in series, is mainly characterized by the efficient pretreatment of the original complex and turbulent gas-liquid mixture flow field through two-stage kinetic energy reduction, without relying on external power or moving parts.

[0031] The stable stratified flow field described above provides crucial and ideal pre-flow field conditions for the subsequent Venturi tube dual-frequency measurement system to independently and accurately acquire frequency signals from the upper and lower layers of media with different liquid contents, while ensuring extremely high operational reliability and long-term maintenance-free characteristics.

[0032] It also includes a differential pressure measurement and monitoring component, which includes pressure tapping holes opened on the wall of the measuring tube 2 on both sides of the conical orifice plate 24, a differential pressure tapping tube 3 installed on the pressure tapping holes, and a differential pressure transmitter 5 connected to the differential pressure tapping tube 3 through a valve group 4. The differential pressure transmitter 5 is connected to the signal processing component through the differential pressure transmitter and converter connecting pipe 6.

[0033] In order to accurately measure the pressure difference between the front and rear sides of the conical orifice plate 24 and to monitor the flow and safety status in the pipeline in real time, this solution is specially equipped with a differential pressure measurement and monitoring component.

[0034] Two pressure tapping holes are precisely machined on the wall of the measuring tube 2 at specific positions upstream and downstream of the conical orifice plate 24. These two pressure tapping holes are reliably connected to the differential pressure tapping tube 3 by welding, and are used to directly extract the pressure before and after the orifice plate.

[0035] The differential pressure tapping pipe 3 guides the extracted pressure signal to a valve group 4. The valve group 4 usually has functions such as shut-off and balancing. Its core functions are: first, to facilitate the isolation of instruments during maintenance; and second, to ensure safe operation of the differential pressure transmitter 5 during commissioning or calibration through the balancing valve, preventing pressure shock on one side.

[0036] The upstream and downstream pressure difference signal accurately measured by differential pressure transmitter 5 The data is transmitted to converter 15 for subsequent traffic cross-validation and system security monitoring.

[0037] After passing through valve group 4, the pressure signal is transmitted to the core measuring instrument, namely differential pressure transmitter 5. The transmitter accurately senses the pressure difference transmitted from the pressure tapping tubes on both sides through its internal sensitive element, such as a capacitive diaphragm, and converts it into a standard electrical signal. Subsequently, this electrical signal is transmitted to the downstream signal processing component, namely converter 15, through a dedicated differential pressure transmitter and converter connection tube 6, which is usually a cable or communication line.

[0038] As a metering unit, based on the relationship between the differential pressure of the conical orifice plate 24 and the fluid flow rate (e.g., the square of the flow rate is proportional to the differential pressure), combined with parameters such as the medium density, it can assist in calculating the total flow rate in the pipeline, serving as a backup or reference measurement.

[0039] As a safety monitoring unit, it can continuously monitor the pressure difference changes on both sides of the orifice plate. Under normal operating conditions, the pressure difference should be kept within a relatively stable range. If the pressure difference is abnormal and continues to increase, it is very likely that impurities have accumulated or blocked at point 24 of the conical orifice plate.

[0040] When the differential pressure exceeds the preset safety limit, the system can trigger an alarm to prompt maintenance personnel to intervene in a timely manner, thereby effectively preventing metering inaccuracies or abnormal pipeline pressure caused by blockage, and greatly improving the operational reliability and safety of the entire flow meter system.

[0041] The frequency signal generation and acquisition assembly also includes an upper mounting structure for mounting and sealing the upper frequency probe 28, and a lower mounting structure for mounting and sealing the lower frequency probe 32. The upper mounting structure includes an upper base 16 mounted on the upper part of the venturi tube 11, an upper sealing gasket 27 disposed in the groove of the upper base 16, and an upper pressure cover 30. The upper pressure cover 30 is fastened to the upper base 16 by upper pressure cover fixing screws 29 to press and seal the upper sealing gasket 27 and the upper frequency probe 28. The lower mounting structure includes a lower base 19 installed at the bottom of the venturi tube 11, a lower sealing gasket 31 set in the groove of the lower base 19, and a lower pressure cover 34. The lower pressure cover 34 is fastened to the lower base 19 by the lower pressure cover fixing screw 33 to press and seal the lower sealing gasket 31 and the lower frequency probe 32.

[0042] The lower mounting structure also includes a lower cover 21 for protecting the external connections of the lower frequency probe 32. The lower cover 21 is mounted on the lower base 19 by lower cover base fixing screws 20.

[0043] The upper frequency probe 28 is connected to the signal processing component via a vertical connecting rod 18. The connecting rod 18 is connected to the upper base 16 via a connecting rod base fixing screw 17. The lower frequency probe 32 is connected to the signal processing component via a lower cover and a connecting rod connecting tube 22.

[0044] The pressure measurement assembly includes a pressure tapping tube 12 located at the front of the venturi tube 11 and a pressure transmitter 13 connected to the pressure tapping tube 12. The pressure transmitter 13 is connected to the signal processing assembly via a pressure transmitter-to-converter connection tube 14. The signal processing assembly is a converter 15.

[0045] Among them, the Venturi tube dual-frequency measurement system is the core metering unit in this scheme. Its working process begins with the stratified medium after the previous stage separation. When the medium enters the Venturi tube 11 through the Venturi tube inlet flange 9, it first flows through the pressure tapping pipe 12 at the front. The pressure transmitter 13 at this point detects the absolute pressure of the medium in real time and transmits the pressure signal to the converter 15 through the pressure transmitter and converter connection pipe 14. This provides key pressure parameters for subsequent flow calculation and performs safety pressure monitoring.

[0046] Subsequently, the gas-liquid mixture with lower liquid content and lower density tends to flow in the upper part of the pipeline; while the gas-liquid mixture with higher liquid content and higher density converges in the middle and lower part of the pipeline.

[0047] The aforementioned stratified medium enters the constriction section of the venturi tube, where the flow velocity gradually increases. When the medium reaches the throat, it flows through the generator 35, which is fixedly installed there. The generator 35 forces the fluid to generate regular vortices and fall off, i.e., the Karman vortex phenomenon.

[0048] Since the liquid content has been stratified in the preceding stage, the upper layer of low liquid content medium and the lower layer of high liquid content medium flowing through the generator 35 have drastically different vortex shedding frequencies due to the difference in density and flow velocity. The upper layer has a higher frequency and the lower layer has a lower frequency.

[0049] This physical phenomenon is precisely captured by the following upper frequency probe 28 and lower frequency probe 32. The two probes are respectively mounted on the upper mounting structure consisting of upper sealing gasket 27, upper base 16, upper pressure cover 30 and upper pressure cover fixing screw 29; and on the lower mounting structure consisting of lower sealing gasket 31, lower base 19, lower pressure cover 34, lower pressure cover fixing screw 33 and lower cover 21. They are firmly and sealed at the precise positions on the upper and lower parts of the Venturi tube 11, ensuring that their sensing end is located at the optimal detection point behind the generator 35.

[0050] The high-frequency and low-frequency signals collected by the upper and lower frequency probes are transmitted to the converter 15 through the connecting rod 18 and the connecting tube 22 of the lower cover and the connecting rod, respectively. The connecting rod 18 is fixed to the upper base 16 by the connecting rod base fixing screw 17, which has the functions of signal transmission and structural support. After receiving the two frequency signals and the pressure signal from the pressure transmitter 13, the converter 15 uses the built-in spectrum analysis algorithm to compare, calculate and compensate the upper and lower layer signals, and finally calculates the gas phase flow rate, liquid phase flow rate and overall liquid content.

[0051] In the specific implementation of this scheme, the calculation of gas volumetric flow rate, liquid volumetric flow rate, and overall liquid content is completed by the converter 15 through its built-in dedicated algorithm. The core of this algorithm is based on the vortex measurement principle, and its basic calculation relationship for operating flow rate is as follows: (In the formula: It's traffic. It's frequency. This flowmeter incorporates frequency signals from both upper and lower probes for reference calculations, achieving a gas flow range ratio of up to 40:1. It also features dynamic temperature and pressure compensation, integrating dynamic measurements of medium pressure and temperature. These measurements are used to compensate for the calculated density value in real time, significantly improving measurement accuracy. This effectively addresses the impact of different liquid components in mixed liquid media on density measurement, thereby enhancing accuracy. The flowmeter exhibits excellent measurement performance for low-velocity gaseous fluids, with a minimum flow velocity of approximately 1 m / s. It is suitable for a wide range of applications and offers significant economic benefits.

[0052] Converter 15 synchronously acquires high-frequency signals from upper frequency probe 28. Low-frequency signal from lower frequency probe 32 The absolute pressure of the pressure transmitter 13 and the medium temperature measured by the temperature sensor integrated in the probe are all pre-processed through filtering and noise reduction to ensure stability and reliability.

[0053] Based on the real-time measured pressure and temperature, and combined with preset gas composition or property parameters, converter 15 dynamically calculates the actual density of pure gas under the current operating conditions, while the density of liquid is processed according to known physical properties. This step aims to provide accurate density parameters for subsequent accurate calculation and standardized conversion of gas flow rate, and eliminate the influence of temperature and pressure changes on the measurement results.

[0054] Converter 15 invokes a dedicated calculation model that has been rigorously calibrated at the factory. The core of this model lies in the correlation and comparison analysis of the frequency signals measured by the upper and lower probes: Under ideal pure gas conditions, the flow field is uniform, and the frequencies collected by the upper and lower frequency probes are... and They are basically the same, and their operating flow calculations satisfy a unified formula: .

[0055] When the gas contains liquid, after energy dissipation and separation by the pre-stage dual-cavity structure, the liquid-containing gas sinks, forming a stratified flow field. At this time, the upper frequency probe 28 collects the medium frequency, which is mainly composed of gas. The frequency of the medium, which is mainly composed of gas and liquid mixtures, is greater than that of the lower frequency probe 32. . and This forms the basis for spectrum analysis, and and The frequency difference is determined by the liquid content of the medium at the lower probe.

[0056] Meanwhile, because the stratospheric gas where the lower frequency probe 32 is located has high humidity and high density, the intensity of the vortex signal it generates is relatively higher than that of the signal from the upper frequency probe 28. This is determined by the frequency value ( , By combining the comprehensive reference calculation of the signal strength, the liquid content of the gas can be accurately calculated.

[0057] In this invention, the frequency collected by the upper frequency probe 28 is... As a reference frequency, it is of utmost importance. Without this reference frequency... For reference, the frequency measured solely by the lower frequency probe 32 Effective liquid content measurement will be impossible, resulting in chaotic signals and irregular fluctuations in measurement data.

[0058] Output and Conversion: By solving the above model, converter 15 directly obtains the gas phase volumetric flow rate under operating conditions. and liquid volume flow rate And overall volumetric liquid content, total flow rate under operating conditions. + .

[0059] Converter 15 can further utilize the compensated gas density This converts the operating flow rate into the volumetric or mass flow rate under standard conditions to meet the needs of trade settlement and other purposes.

[0060] The formula for converting operating conditions to standard conditions flow rate is: Where P, T, and Z are the operating pressure, temperature, and compressibility factor, respectively. These are the corresponding values ​​under standard conditions, with the liquid content being directly output as a key process parameter.

[0061] Cross-validation and security monitoring: Converter 15 simultaneously reads the differential pressure across the conical orifice 24 measured by differential pressure transmitter 5. This differential pressure can be used to calculate the orifice plate flow rate using the following formula: (In the formula: The mixture flow rate is estimated for the orifice plate, where K is the orifice plate flow coefficient. The perforated area of ​​the perforated plate. To estimate the total flow rate of a mixed medium (based on the density of the mixed medium automatically calculated by the program according to the real-time liquid content), a reference value is needed. This reference value is compared with the total flow Q calculated by the dual-frequency system to achieve cross-validation and enhance the system's credibility.

[0062] The system has comprehensive security monitoring and early warning functions: Anti-blockage warning: If the measured gas flow rate does not change significantly or continues to decrease, but the orifice plate differential pressure value continues to increase, it indicates that there may be a blockage in the conical orifice plate 24 or inside the pipeline, and the system will issue an early warning.

[0063] Instrument status monitoring: The system has built-in pressure and temperature measurement probes to monitor the pressure and temperature signals of the measurement system itself, and the system will issue an early warning when the data is abnormal.

[0064] Abnormal operating condition warning: If the system measures the liquid content to be close to 100% for an extended period of time, it indicates that the gas well may be producing abnormally or has entered a water flooding state, and the system will issue a warning.

[0065] Over-limit warning: When the gas volume calculated by the vortex frequency increases abnormally and exceeds the design value, and the differential pressure measurement data also exceeds the threshold simultaneously, the system issues an over-range or abnormal flow field warning.

[0066] In summary, this system can not only reliably measure gas-liquid mixtures, but also monitor gas well pressure, temperature, flow rate, and status in real time, eliminating the need for on-site inspections and greatly improving the safety of gas well operations.

[0067] By employing the aforementioned original dual-frequency signal reference calculation model, combined with real-time temperature and pressure compensation and cross-validation mechanisms, the required gas phase volumetric flow rate, liquid phase volumetric flow rate, and liquid content can be directly and accurately calculated. This fully leverages the synergistic advantages of dual-cavity separation and dual-frequency measurement, making it the core algorithm for achieving high precision, wide adaptability, and high reliability.

[0068] The entire measuring tube system is seamlessly connected to this system via a flange connection system. Specifically, the measuring tube outlet flange 7 of the front-end measuring tube system and the venturi tube inlet flange 9 of this system are aligned and connected by fasteners 10, and a sealing gasket 8 is pressed between the two flange faces to ensure the continuity and sealing of the entire flow channel from pretreatment to precision measurement. The treated medium finally flows out through the outlet flange 23 welded to the rear of the venturi tube 11.

[0069] Temperature sensors are installed on both the upper frequency probe 28 and the lower frequency probe 32.

[0070] Both the upper frequency probe 28 and the lower frequency probe 32 integrate temperature sensors. The temperature sensor is directly encapsulated or embedded inside or near the sensing unit of the frequency probe. Its installation method ensures that the temperature sensing element of the sensor can directly or indirectly contact the medium flowing through the probe through a thermally conductive structure, thereby quickly and accurately sensing the temperature of the medium.

[0071] Medium temperature is a key parameter for calculating gas density and converting flow rate. By acquiring temperature data in real time and combining it with pressure data measured by pressure transmitter 13, converter 15 can calculate the true density of the gas medium under the current operating conditions in real time and accurately according to the gas state equation, thereby dynamically compensating for the gas flow measurement results and significantly improving the overall measurement accuracy of the flow meter under temperature and pressure change conditions.

[0072] Meanwhile, the temperature measurement function is integrated into the frequency probe, eliminating the need to open a separate thermometer interface on the pipeline and install an independent temperature transmitter. This not only simplifies the overall structure of the flow meter, reduces manufacturing costs and installation complexity, but also reduces potential leakage points and failure points, and improves the reliability and compactness of the system.

[0073] Since the temperature sensors are located in the upper and lower flow layers of the venturi tube, they can more accurately reflect the temperature of the medium in each flow layer. Especially when there may be a small temperature difference between the upper and lower flow layers, using two measurements, or taking their average, or using them separately for calculations of the corresponding flow layers, can obtain a more representative overall medium temperature than a single temperature measurement method located on the tube wall, further optimizing the compensation effect.

[0074] Integrating a temperature sensor into a frequency probe is an important design for optimizing measurement accuracy, reliability, and economy at the system level, providing a solid guarantee for achieving high-performance metrology in complex industrial environments.

[0075] The front and rear ends of the venturi tube dual-frequency measurement system are respectively equipped with a venturi tube inlet flange 9 and an outlet flange 23. The measuring tube outlet flange 7 of the measuring tube system is connected to the venturi tube inlet flange 9 by fasteners 10 and gaskets 8.

[0076] Among them, the flange connection between the Venturi tube dual-frequency measurement system and the measurement tube system is a key structural design for realizing the modularization, integration and reliable sealing of the entire flowmeter.

[0077] Specifically, at the end of the measuring tube system, there is a measuring tube outlet flange 7; at the inlet end of the venturi tube dual-frequency measuring system, there is a matching venturi tube inlet flange 9.

[0078] During installation, a sealing gasket 8 is first placed between the flange faces where they meet. This sealing gasket is usually made of materials with good elasticity and resistance to media corrosion, such as metal spiral wound gaskets or graphite gaskets. Its function is to fill the microscopic unevenness of the flange surface and form the first reliable static seal.

[0079] Then, fasteners 10, typically a set of bolts, nuts, and washers, are passed sequentially through the corresponding bolt holes on the two flanges and tightened evenly in a specified torque sequence.

[0080] The tightening process causes the flange face to press against the gasket, causing it to undergo elastic or plastic deformation, thereby establishing a strong and tight pressure seal barrier at the joint surface of the two components, ensuring that the fluid medium does not leak during the transition from the measuring tube to the venturi tube.

[0081] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A novel dual-chamber structure gas-liquid two-phase wet gas flow meter, characterized in that, include: Measuring tube system: The measuring tube system is used to perform preliminary kinetic energy reduction and separation of the gas-liquid mixture to form a stratified flow of the gas-liquid mixture with different liquid contents; Venturi tube dual-frequency measurement system: The Venturi tube dual-frequency measurement system is connected to the rear end of the measurement tube system and is used to receive the stratified gas-liquid mixture. The venturi dual-frequency measurement system includes a venturi tube (11), a pressure measurement component, a frequency signal generation and acquisition component, and a signal processing component; The venturi tube (11) is equipped with a generator (35) at the throat inlet to generate a vortex in the gas-liquid mixture. The pressure measurement component is used to measure the pressure of the medium; The frequency signal generation and acquisition component includes an upper frequency probe (28) and a lower frequency probe (32) inserted from the upper and lower parts of the venturi tube (11) and located behind the generator (35), respectively, for acquiring the high frequency signal generated by the upper low liquid content gas-liquid mixture vortex and the low frequency signal generated by the lower high liquid content gas-liquid mixture vortex. The signal processing component is used to receive pressure signals and upper and lower frequency signals, and to analyze the liquid content by comparing the spectrum, thereby calculating the gas flow rate and liquid flow rate.

2. The novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 1, characterized in that, The measuring tube system includes a measuring tube (2), a tapered orifice plate (24) and a cone (25) installed inside the measuring tube (2), and an inlet flange (1) connected to the inlet end of the measuring tube (2). The tapered orifice plate (24) is installed in the middle of the measuring tube (2) to form a first chamber. The cone (25) is installed in the measuring tube (2) behind the tapered orifice plate (24) by a cone fixing bracket (26) to form a second chamber. The measuring tube system has a measuring tube outlet flange (7) installed at the rear end.

3. The novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 1, characterized in that, It also includes a differential pressure measurement and monitoring component, which includes pressure tapping holes on the wall of the measuring tube (2) on both sides of the conical orifice plate (24), a differential pressure tapping tube (3) installed on the pressure tapping holes, and a differential pressure transmitter (5) connected to the differential pressure tapping tube (3) through a valve group (4). The differential pressure transmitter (5) is connected to the signal processing component through a differential pressure transmitter and converter connecting pipe (6).

4. The novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 1, characterized in that, The frequency signal generation and acquisition component also includes an upper mounting structure for mounting and sealing the upper frequency probe (28) and a lower mounting structure for mounting and sealing the lower frequency probe (32); The upper mounting structure includes an upper base (16) installed on the upper part of the venturi tube (11), an upper sealing gasket (27) set in the groove of the upper base (16), and an upper pressure cover (30). The upper pressure cover (30) is fastened to the upper base (16) by upper pressure cover fixing screws (29) to press and seal the upper sealing gasket (27) and the upper frequency probe (28). The lower mounting structure includes a lower base (19) installed at the bottom of the venturi tube (11), a lower sealing gasket (31) set in the groove of the lower base (19), and a lower pressure cover (34). The lower pressure cover (34) is fastened to the lower base (19) by a lower pressure cover fixing screw (33) to press and seal the lower sealing gasket (31) and the lower frequency probe (32).

5. A novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 4, characterized in that, The lower mounting structure also includes a lower cover (21) for protecting the external connection of the lower frequency probe (32), the lower cover (21) being mounted on the lower base (19) by a lower cover base fixing screw (20).

6. The novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 4, characterized in that, The upper frequency probe (28) is connected to the signal processing component via a vertical connecting rod (18). The connecting rod (18) is connected to the upper base (16) via a connecting rod base fixing screw (17). The lower frequency probe (32) is connected to the signal processing component via a lower cover and a connecting rod connecting tube (22).

7. A novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 1, characterized in that, The pressure measurement assembly includes a pressure tapping tube (12) located at the front of the venturi tube (11) and a pressure transmitter (13) connected to the pressure tapping tube (12). The pressure transmitter (13) is connected to the signal processing assembly via a pressure transmitter-to-converter connection tube (14).

8. A novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 1, characterized in that, The signal processing component is a converter (15).

9. A novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 4, characterized in that, Both the upper frequency probe (28) and the lower frequency probe (32) are equipped with temperature sensors.

10. A novel dual-cavity gas-liquid two-phase wet gas flow meter as described in claim 1, characterized in that, The front and rear ends of the Venturi tube dual-frequency measurement system are respectively provided with a Venturi tube inlet flange (9) and an outlet flange (23). The measuring tube outlet flange (7) of the measuring tube system is connected to the Venturi tube inlet flange (9) by fasteners (10) and gaskets (8).

Images