Gas runner flowmeter with rectification acceleration function

Abstract

The invention relates to the technical field of gas flow metering, and particularly discloses a gas runner flowmeter with rectification and acceleration functions, the gas runner flowmeter comprises a shell and a runner, the top of the shell is provided with a sensor and a flow converter which are electrically connected; the shell comprises a contraction section, a throat section and an expansion section which are sequentially arranged in the gas flowing direction, the inner diameter of the contraction section is gradually reduced in the gas flowing direction, and the inner diameter of the expansion section is gradually increased in the gas flowing direction; a hollow shaft is arranged at the top of the throat section, and the bottom of the hollow shaft is communicated with the top of the throat section; a connecting assembly is arranged in the hollow shaft, the rotating wheel is rotationally connected into the hollow shaft through the connecting assembly, the axis of the rotating wheel is perpendicular to the axis of the throat section, and blades on the lower portion of the rotating wheel extend into the throat section. According to the technical scheme, the technical problems that in the prior art, normal work cannot be achieved under the working condition that the pipeline pressure is small or the gas flow speed is low, and the measuring capacity is limited under the small-flow working condition can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas flow measurement, in particular to a gas rotor flowmeter with rectification and acceleration functions. Background Art

[0002] Gas turbine flowmeter is an instrument specially used to measure gas flow. Figure 1 As shown, an existing gas turbine flowmeter primarily consists of a housing 101, a turbine 102, a sensor 103, and a signal processor 104. The turbine 102 is mounted coaxially with the housing 101 via a bearing system. The sensor 103 is attached to the top of the housing 101, and the signal processor 104 is electrically connected to the sensor 103. When gas passes through the flowmeter, it generates radial thrust on the turbine 102 within the housing 101, causing it to rotate. The speed of the turbine 102 is proportional to the gas flow rate. The sensor 103 detects the rotational speed of the turbine 102 and generates a pulse signal that is sent to the signal processor 104. The signal processor 104 accurately calculates the gas flow rate based on the received pulse signal.

[0003] The above-mentioned prior art still has the following problems when actually used: (1) Because the turbine of a gas turbine flowmeter is mounted on the central axis of the housing through a bearing system, its structural characteristics result in a large flow resistance when the gas passes through it, which usually causes a 40% to 50% pipeline pressure loss. Under conditions where the pipeline pressure is low or the gas flow rate is low, this pressure loss may cause the flowmeter to be unable to obtain sufficient pressure difference to start and maintain operation, resulting in the device not being able to work properly, limiting its measurement capability under low flow conditions.

[0004] (2) In actual working conditions, there are application scenarios where the gas dust content is high or the gas purification level is insufficient. In this case, the gas medium often contains a certain amount of solid particle impurities. These particles can easily enter the gap between the turbine and the casing, causing the turbine to stagnate or even completely jam, resulting in the flow meter not being able to work properly. In addition, long-term operation of the flow meter may also cause turbine wear, deformation, or even fracture, seriously affecting the stability of the equipment and the flow measurement accuracy.

[0005] Based on this, the present application proposes a gas rotary flowmeter with a rectification and acceleration function to improve the measurement capability of the equipment under low flow conditions, and to improve the operating stability and flow measurement accuracy of the equipment. Summary of the Invention

[0006] The present invention aims to provide a gas rotary flowmeter with rectification and acceleration functions to solve the technical problems that the existing technology cannot work normally under conditions of low pipeline pressure or low gas flow rate, and has limited measurement capabilities under low flow conditions.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A gas rotor flowmeter with a rectifying and accelerating function comprises a housing and a rotor, a sensor is provided on the top of the housing, a flow converter is provided on the top of the sensor, and the sensor is electrically connected to the flow converter; the housing comprises a contraction section, a throat section and an expansion section arranged in sequence along the gas flow direction, the inner diameter of the contraction section gradually decreases along the gas flow direction to be equal to the inner diameter of the throat section, and the inner diameter of the expansion section gradually increases along the gas flow direction from being equal to the inner diameter of the throat section; a hollow shaft is provided on the top of the throat section, and the bottom of the hollow shaft is connected to the top of the throat section; a connecting assembly is provided in the hollow shaft, and the rotor is rotatably connected to the hollow shaft through the connecting assembly, the axis of the rotor is perpendicular to the axis of the throat section, and the blades at the lower part of the rotor extend into the throat section from the connection between the hollow shaft and the throat section.

[0008] The principles and advantages of this solution are: In actual use, gas passes through the contraction, throat, and expansion sections of the housing in sequence. In the throat section, the gas pushes the blades extending into the lower portion of the runner, causing the runner to rotate. The runner's speed is proportional to the gas flow rate. A sensor detects the runner's rotational speed and generates a pulse signal that is sent to a flow converter. The flow converter accurately calculates the gas flow rate based on the received pulse signal.

[0009] 1. This solution sets a hollow shaft on the top of the housing, and rotatably connects the runner to the hollow shaft through a connecting assembly, thereby achieving installation of the runner outside the housing. The blades of the runner extend into the housing from the connection between the hollow shaft and the housing, that is, only the lower blades of the entire runner are located in the housing. Compared with the prior art method of installing the entire turbine in the housing through a bearing system, this solution can avoid generating large flow resistance when the gas passes through, thereby greatly reducing pipeline pressure loss. In this way, even under conditions where the pipeline pressure is low or the gas flow rate is low, it can ensure that the flowmeter can obtain sufficient pressure difference to start and maintain operation, thereby ensuring the normal operation of the equipment and its measurement capability under low flow conditions.

[0010] 2. This solution improves not only the rotor's mounting position relative to the housing, but also its mounting method. Specifically, the rotor's axis is positioned perpendicular to the housing's axis. This ensures that the gas flow is perpendicular to the rotor's blade surface. Even if only the rotor's lower blades extend (or even partially extend) into the housing, the flowing gas effectively drives the rotor blades, allowing the rotor to rotate in sync with the gas flow, ensuring proper operation of the device and effective measurement of gas flow.

[0011] 3. This solution improves the installation position and method of the impeller relative to the housing, creating a larger gap between the blades extending from the turbine into the housing and the inner wall of the housing. Even in applications with high dust content or insufficient gas purification, solid particulate impurities in the gas medium are less likely to accumulate in the gap between the blades and the inner wall of the housing. This effectively prevents the impeller from becoming stuck or even completely stuck, thus ensuring the proper functioning of the flowmeter. Furthermore, long-term operation of the flowmeter can prevent impeller blade wear, deformation, or even breakage, thereby ensuring device stability and flow measurement accuracy.

[0012] 4. This solution sets the shell to include a contraction section, a throat section, and an expansion section arranged in sequence along the direction of gas flow, which can effectively reduce the gas flow resistance and increase the gas flow rate through the Venturi tube principle. Specifically, the contraction section gradually reduces its inner diameter along the direction of gas flow, which can accelerate the gas flow rate, increase kinetic energy, and reduce pressure; the throat section maintains the minimum inner diameter, that is, maintains the minimum cross-sectional area, which can ensure high-speed gas flow while reducing turbulence; the expansion section gradually increases its inner diameter along the direction of gas flow, that is, gradually expands its cross-sectional area, which can restore part of the gas static pressure and reduce energy loss. In this way, this solution can not only effectively reduce the gas flow resistance, but also rectify the gas flow field, making the gas flow more uniform and stable, further reducing pressure loss, and thus further improving the measurement capability of the equipment under low flow conditions.

[0013] 5. By configuring the contraction, throat, and expansion sections, this solution allows for a more concentrated and orderly flow within the housing. This reduces the chance of particles in the gas entering the gap between the impeller blades extending into the housing and the inner wall of the housing, further preventing the impeller from becoming stuck or even completely stuck, thus ensuring the proper functioning of the flowmeter. Furthermore, the smoother flow field reduces the impact and wear of solid particles in the gas on the impeller blades, thereby extending the impeller's service life.

[0014] 6. The large flow resistance generated by existing gas turbine flowmeters when gas passes through can lead to unstable flow fields and affect measurement accuracy. Especially in application scenarios with high dust content or insufficient gas purification, particulate impurities in the gas medium will further interfere with the flow field, resulting in inaccurate measurement results. This solution, through the provision of a contraction section, a throat section, and an expansion section, helps to form a more stable flow field in the casing, reduce turbulence and other disturbance factors, and help improve measurement accuracy. In addition, a more uniform flow field and higher flow rate enable the sensor to more accurately detect the rotation frequency of the impeller, thereby improving the sensitivity and response speed of the entire system.

[0015] To sum up, this solution improves the structure of the casing, the installation position and method of the impeller relative to the casing, which can reduce pipeline pressure loss and enhance the ability to resist particulate impurities, so that it can work normally under lower pipeline pressure and gas flow rate conditions, expand the application range of the equipment under small flow conditions, and also improve the measurement accuracy of the equipment.

[0016] Prior to proposing this solution, the inventors attempted to improve the connection structure between the rotor and the housing. Specifically, they replaced the existing bearing system with a single needle roller bearing coaxially fixed to the inner wall of the housing. The shaftless rotor then coaxially interference fit within the inner ring of the needle roller bearing to achieve the connection. While the volume of a single needle roller bearing is smaller than that of a bearing system, it can somewhat reduce the flow resistance generated by gas passage and reduce pipeline pressure loss, thereby improving the device's measurement capabilities under low-flow conditions. However, in actual use, they discovered that this connection method, with the rotor and needle roller bearing integrally located within the housing and requiring dimensions to be compatible with the housing to achieve connection, still generated significant flow resistance during gas passage, resulting in significant pipeline pressure loss, significantly limiting the device's measurement capabilities under low-flow conditions. After repeated improvements and trials, the inventors finally broke through the conventional thinking of "improving the rotor-housing connection structure" and, based on this, innovatively proposed improvements to the rotor's mounting position and method relative to the housing, resulting in the technical solution claimed in this application and achieving the aforementioned technical effects.

[0017] Preferably, as an improvement, the connecting assembly includes bearing seats symmetrically arranged on both sides of the rotating wheel, and the bearing seats are fixedly connected to the hollow shaft; a connecting shaft is coaxially fixedly plugged into the rotating wheel, and both ends of the connecting shaft are rotatably connected to the corresponding bearing seats through miniature bearings.

[0018] Beneficial effects: This solution fixes two bearing seats on the hollow shaft on both sides of the runner, fixes and plugs the connecting shaft on the runner, and rotatably connects the two ends of the connecting shaft to the corresponding bearing seats through miniature bearings, thereby realizing the rotational connection between the runner and the bearing seat, thereby realizing the rotational connection between the runner and the hollow shaft. The structure is simple and reliable, and it is easy to install.

[0019] Preferably, as an improvement, the bearing seat is slidably inserted in the hollow shaft, and the outer wall of the bearing seat cooperates with the inner wall step of the hollow shaft; screw plugs are inserted at both ends of the hollow shaft, the screw plugs cooperate with the hollow shaft threads, and the screw plugs abut against the bearing seat.

[0020] Beneficial Effects: This solution allows the bearing seat to be slidably inserted into the hollow shaft and matched with the hollow shaft step. Screw plugs threaded onto both ends of the hollow shaft abut against the bearing seat, enabling a detachable connection between the bearing seat and the hollow shaft. This structure is simple and reliable. Furthermore, by creating an interference fit between the connecting shaft, miniature bearing, and bearing seat, a detachable connection can be achieved, thus achieving a detachable connection of the entire connection assembly, facilitating subsequent maintenance and replacement.

[0021] Preferably, as an improvement, a sealing gasket is sleeved on the screw plug, and the sealing gasket abuts between the screw plug and the hollow shaft; And / or, a shaft sleeve is provided between the miniature bearing and the bearing seat.

[0022] Beneficial effects: In this solution, a sealing gasket is connected between the screw plug and the hollow shaft. On the one hand, the sealing gasket can provide an effective sealing layer to prevent the gas overflowing from the outer shell to the hollow shaft from leaking from the connection between the screw plug and the hollow shaft; on the other hand, direct contact between the screw plug and the hollow shaft may cause wear or damage, especially in the case of frequent disassembly and assembly. The addition of a sealing gasket can form a buffer layer between the screw plug and the hollow shaft, reducing the direct friction and wear between the metal parts, thereby helping to extend the service life of the screw plug and the hollow shaft, and reducing maintenance costs and replacement frequency.

[0023] This solution adds a sleeve between the miniature bearing and the bearing seat. On the one hand, the sleeve can provide an additional protective layer between the miniature bearing and the bearing seat, reducing the wear caused by direct contact between the two. Especially in application scenarios with high loads or frequent starts and stops, the sleeve can significantly extend the service life of the miniature bearing; on the other hand, the sleeve can form a barrier between the miniature bearing and the external environment, preventing dust, particles or other impurities from entering the bearing, avoiding these pollutants from damaging the miniature bearing and extending the service life of the bearing.

[0024] Preferably, as an improvement, the cross section of the contraction section is a straight line, the diameter ratio of the outlet and the inlet of the contraction section is 0.65, and the length of the contraction section is 1.5 times the diameter of the inlet.

[0025] Beneficial effects: This solution sets the diameter ratio of the outlet and inlet of the contraction section to 0.65. On the one hand, this diameter ratio indicates that the contraction amplitude of the contraction section is larger. Under the premise that the gas flow rate remains unchanged, the flow area is greatly reduced, so that the gas can obtain a higher flow rate at the outlet of the contraction section (i.e., the inlet of the throat section), which helps to overcome the problem of difficulty in starting the sensor at low flow rates and enhance the response capability of the flow meter under low flow conditions; on the other hand, this diameter ratio will not cause severe disturbances, making the airflow in the casing more concentrated and uniform, reducing turbulence and improving measurement accuracy.

[0026] This solution sets the length of the contraction section to 1.5 times the inlet diameter, resulting in a more gradual contraction process and avoiding the localized resistance caused by abrupt changes. This moderate contraction section length allows for gradual contraction, effectively reducing the risk of flow separation and vortex formation, thereby minimizing energy loss. Furthermore, a reasonable contraction angle and smooth transition help eliminate non-ideal flow patterns (such as vortices and deflection) in the upstream pipeline, acting as a rectifier, creating a more stable flow field in the contraction section and improving overall system efficiency.

[0027] Preferably, as an improvement, the cross section of the contraction section is a curve, the area ratio of the inlet and outlet of the contraction section is 2.65, and the length of the contraction section is twice the diameter of the inlet; And the profile curve of the contraction section follows the entrusted Sinski curve formula: ; Among them, R is the radius of any position of the contraction section, R0 is the radius of the contraction section outlet, R n is the radius of the inlet of the contraction section, X is the length from the inlet of the contraction section to any position, and L is the length of the contraction section.

[0028] Beneficial Effects: By introducing the Witoshinsky curve and combining it with a reasonable area ratio (2.65) and length ratio (twice the inlet diameter), this solution achieves efficient and stable acceleration of the airflow in the contraction section, improving the accuracy and reliability of the measurement system, as described below.

[0029] This solution sets the area ratio of the inlet and outlet of the contraction section to 2.65, which means that the airflow velocity increases significantly after contraction. An area ratio within a reasonable range helps to form a straight and uniform flow in the throat section (i.e., airflow with consistent velocity and direction), thereby reducing airflow disturbances and improving the accuracy and repeatability of measurement data.

[0030] This solution sets the length of the contraction section to twice the inlet diameter. This ensures sufficient transition space for airflow acceleration and smooth transition while avoiding excessive length. A shorter contraction section helps reduce overall equipment size and is suitable for space-constrained applications.

[0031] This solution sets the cross-section of the contraction section as a curve, and the cross-section curve of the contraction section follows the Witosinski curve formula. Because the Witosinski curve is a smooth, continuously changing curve form, it can achieve smooth airflow acceleration within the contraction section. Compared with a contraction section with a diameter cross-section, a contraction section with a Witosinski curve cross-section can reduce flow separation and boundary layer disturbances, thereby reducing turbulence and energy loss.

[0032] Based on the smooth transition characteristics of the Witosinski curve, combined with a reasonable area ratio and length design, the airflow can achieve a more ideal flow state when entering the throat section, improve the consistency of the flow state of the airflow in the throat section, and thus enhance the accuracy of the measurement data.

[0033] In addition, the Witoshinsky-type curve has a clear mathematical expression, which facilitates numerical simulation and theoretical analysis. Combined with the known area ratio and length parameters, it can accurately predict the airflow behavior in the design stage and improve the reliability of engineering design.

[0034] Preferably, as an improvement, the diameter of the throat section is the same as the diameter of the outlet of the contraction section, and the length of the throat section is 0.8 times the diameter.

[0035] Beneficial Effects: Since the outlet of the contraction section is the part with the smallest diameter, this solution sets the diameter of the throat section to be equal to the diameter of the outlet of the contraction section. This ensures that the throat section is the part with the smallest cross-sectional area when the gas passes through the shell. According to the continuity equation and Bernoulli equation, the gas flow rate reaches its maximum value at this position, while the static pressure drops to its minimum. The smaller diameter of the throat section ensures that the gas reaches a higher flow rate in this area, allowing the impeller to have a higher rotational speed, thereby ensuring that the sensor has sufficient signal strength to detect the rotational frequency of the impeller. In addition, the low-pressure area formed in the throat section helps to improve the sensitivity of the system, so that a significant pressure difference can be obtained even at a lower inlet flow rate, facilitating accurate measurement.

[0036] This solution sets the length of the throat section to 0.8 times the diameter. This ratio indicates that the throat section is relatively short, but still has sufficient length to maintain stable flow field conditions. Specifically, a shorter throat section can avoid flow separation or turbulence formation caused by excessive length, maintain the laminar state of the fluid, and thus improve measurement accuracy. The appropriate throat length ensures that a relatively stable low-pressure zone is formed and maintained within the throat section, which is conducive to obtaining an accurate pressure difference signal, thereby improving the accuracy of flow calculations. Although the throat section will produce a certain amount of pressure loss, a reasonable length setting (0.8 times the diameter) can minimize the total pressure difference while ensuring a higher flow rate, and is suitable for application scenarios that are more sensitive to pressure loss.

[0037] Preferably, as an improvement, the shape and size of the expansion section are the same as those of the contraction section, and the expansion section and the contraction section are symmetrically arranged at both ends of the throat section.

[0038] Beneficial effects: (1) Improved airflow uniformity: In the contraction section, the airflow is accelerated and reaches its maximum speed in the throat section. By setting the expansion section symmetrical to the contraction section, the airflow gradually decelerates after passing through the throat section, and the pressure recovery is more stable. The symmetrical setting of the expansion section and the contraction section can reduce the possibility of airflow separation and avoid vortices or turbulence caused by improper setting of the diffusion section, thereby ensuring a more uniform airflow distribution.

[0039] (2) Reduced energy loss: The symmetrical arrangement of the expansion section and the contraction section enables the airflow to restore pressure more smoothly during the diffusion process, reducing the energy loss caused by sudden expansion. This solution is conducive to optimizing the flow characteristics in the flow channel and improving the overall efficiency.

[0040] (3) Improved measurement accuracy: The symmetrical structure helps maintain the straight and uniform flow state of the airflow in the throat section (i.e., the speed is equal and the direction is consistent), thereby reducing airflow disturbances and improving the accuracy and repeatability of measurement data.

[0041] (4) Optimizing flow field stability: The symmetrical structure helps to balance the fluid mechanics effects and reduce vibration or noise problems caused by asymmetric flow, thereby improving the stability and reliability of equipment operation.

[0042] Preferably, as an improvement, the length of the blade of the runner is 15 mm and the width is 10 mm; the length of the blade extending into the throat section is ≥5 mm.

[0043] Beneficial effects: This solution limits the size of the runner blades and the length of the blades extending into the throat section, so that the blades at the lower part of the runner only partially extend into the throat section, and the volume of the blades is relatively small, and the space they occupy in the throat section is limited, so the impact on the gas flow field in the throat section is extremely small.

[0044] (1) Ensure smooth flow in the throat section: Since the blades occupy a small proportion in the throat section, they will hardly cause any obstruction to the gas flow, thereby ensuring that the gas maintains a smooth and stable flow state in the throat section and avoiding sudden changes in flow rate or pressure fluctuations caused by local diameter reduction.

[0045] (2) Effectively avoid particle jamming: Gas may carry a certain amount of solid particles, which can easily get stuck in the gap between the blades and the casing in existing turbine flowmeters, causing equipment failure or damage. In this solution, the blades are smaller and only partially extend into the throat section, greatly reducing the risk of particle jamming and improving the reliability and adaptability of the equipment in dusty gas environments.

[0046] (3) Improved measurement stability and sensitivity: The gas flowing through the throat section drives the rotor to rotate in a straight and uniform flow close to the ideal state, making the rotor movement smoother and more responsive. In conjunction with the sensor, it can accurately capture the rotor rotation frequency, thereby achieving high-precision flow signal acquisition and output.

[0047] (4) Optimizing the performance under low flow conditions: The smaller blade resistance reduces the pressure difference required for the impeller to start, enabling stable rotation of the impeller even under low flow conditions, thereby improving the applicability and measurement accuracy of the equipment under low flow conditions.

[0048] Preferably, as an improvement, the flow converter includes a microcontroller and two operational amplifiers electrically connected to the microcontroller, the sensor is electrically connected to the two operational amplifiers, and the pulse signal output by the sensor is amplified and filtered by the two operational amplifiers in turn and then transmitted to the microcontroller for flow calculation; And / or, the sensor is a magnetoelectric sensor.

[0049] Benefits: The pulse signals output by sensors are typically weak, and direct input to a microcontroller may not accurately identify them. Furthermore, various noise sources exist in real-world environments, which can interfere with sensor signals and affect measurement accuracy. This solution significantly improves the signal-to-noise ratio (SNR) by amplifying and filtering the signal through an operational amplifier, making the useful signal clearer and easier to process. High-quality signal input helps reduce potential misjudgments during the microcontroller's signal recognition process, ensuring that the microcontroller can more accurately calculate gas velocity and flow rate, improving overall measurement accuracy.

[0050] Furthermore, this solution employs two operational amplifiers, allowing for separate amplification and filtering, ensuring signal linearity and stability. The amplification factor and filtering parameters can be flexibly adjusted to suit specific application scenarios and varying operating conditions. This effectively expands the system's dynamic range through appropriate amplification and filtering settings, adapting to varying flow rates from low to high.

[0051] This solution uses a magnetoelectric sensor. This sensor generates a pulse signal by detecting changes in the magnetic field generated by the rotation of a small magnet or magnetic material mounted on the turbine blades. Magnetoelectric sensors are capable of detecting very subtle magnetic field changes and produce clear pulse signals even at low flow rates, ensuring the flowmeter's sensitivity and accuracy under low flow conditions. Since there are no moving parts directly involved in the signal generation process, magnetoelectric sensors offer high reliability and a long service life.

[0052] Preferably, as an improvement, flanges are coaxially fixedly connected at both ends of the housing; And / or, the flow converter is connected to a waterproof connector.

[0053] Benefits: This solution features coaxially fixed flanges at both ends of the housing, enabling quick connection between the flowmeter and external piping. This significantly simplifies installation and removal, eliminating the need for welding or other complex connection methods. When the flowmeter needs to be inspected, calibrated, or repaired, it can be easily removed by simply loosening the flange bolts, reducing downtime and maintenance costs.

[0054] This solution incorporates a waterproof connector connected to the flowmeter. This connector effectively prevents water, moisture, and rain from entering the flowmeter, preventing circuit shorts, corrosion, and signal interference. This significantly improves the device's IP rating, meeting the requirements for use in outdoor or humid environments. In industrial environments subject to spraying, washing, or high humidity (such as food processing, wastewater treatment, and chemical plants), the waterproof connector ensures a stable electrical connection, preventing signal interruptions or equipment failures caused by water ingress, and improving the long-term operational reliability of the flowmeter under harsh conditions.

[0055] In summary, the gas rotary flowmeter with rectification and acceleration function provided in this application has the advantages of wide measurement range (20:1), low pressure loss, low failure rate, strong reliability, high measurement accuracy, etc., and has high economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a structural schematic diagram of an existing gas turbine flowmeter.

[0057] Figure 2This is a schematic diagram of the axial cross-sectional structure of the shell in Example 1 of the present invention.

[0058] Figure 3 This is a schematic diagram of the radial cross-sectional structure of the shell in Example 1 of the present invention.

[0059] Figure 4 This is a schematic diagram of the axial cross-sectional structure of the shell in Example 2 of the present invention.

[0060] Figure 5 for Figure 4 Schematic diagram of the structure of the middle contraction section.

[0061] Figure 6 for Figure 5 Schematic diagram of the cross-sectional curve of the middle contraction section.

[0062] Figure 7 This is a schematic diagram of the axial cross-sectional structure of the shell in Example 3 of the present invention. DETAILED DESCRIPTION

[0063] The following is further described in detail through specific implementation methods: Reference numerals in the drawings of the specification include: housing 101, turbine 102, sensor 103, signal processor 104; Flange 1, shell 2, contraction section 21, throat section 22, expansion section 23, magnetoelectric sensor 3, flow converter 4, waterproof joint 5, screw plug 6, sealing gasket 7, bearing seat 8, runner 9, connecting shaft 10, miniature bearing 11, sleeve 12, hollow shaft 13.

[0064] Example 1 A gas runner 9 flow meter with rectification and acceleration function, as shown in the attached Figure 2 and Figure 3 As shown, the system comprises a housing 2 and a rotor 9. A sensor is fixedly connected to the top of the housing 2, and a flow converter 4 is fixedly connected to the top of the sensor. The sensor and flow converter 4 are electrically connected. Specifically, the sensor is a magnetoelectric sensor 3. The flow converter 4 includes a microcontroller and two operational amplifiers electrically connected to the microcontroller. The magnetoelectric sensor 3 is electrically connected to the two operational amplifiers. The pulse signal output by the magnetoelectric sensor 3 is amplified and filtered by the two operational amplifiers before being transmitted to the microcontroller for flow calculation.

[0065] In this embodiment, the microprocessor uses an STM32F030RCT6 microcontroller produced by STMicroelectronics, which offers fast computing speed and high measurement accuracy. Flanges 1 are coaxially fixedly connected to the housing 2 at both ends. Flanges 1 are fixedly connected to the housing 2 by integral molding or welding. A waterproof connector 5 is connected to the flow converter 4.

[0066] The housing 2 includes a converging section 21, a throat section 22, and a diverging section 23, arranged sequentially along the gas flow direction. These sections are integrally formed. The inner diameter of the converging section 21 gradually decreases along the gas flow direction, with the inner diameter of the smaller end of the converging section 21 being equal to the inner diameter of the throat section 22. The inner diameter of the throat section 22 remains constant. The inner diameter of the diverging section 23 gradually increases along the gas flow direction, with the inner diameter of the smaller end of the diverging section 23 being equal to the inner diameter of the throat section 22.

[0067] In this embodiment, the cross-section of the contraction section 21 is a straight line. The inlet diameter of the contraction section 21 is D, the outlet diameter is d, the diameter ratio d / D between the outlet and the inlet is 0.65, and the length of the contraction section 21 is 1.5D. The diameter of the throat section 22 is the same as the diameter of the outlet of the contraction section 21, that is, the diameter of the throat section 22 is d; the length of the throat section 22 is 0.8 times the diameter, that is, the length of the throat section 22 is 0.8d. The expansion section 23 has the same shape and size as the contraction section 21, and the expansion section 23 is symmetrically arranged at both ends of the throat section 22. Specifically, the inlet diameter of the expansion section 23 is d, the outlet diameter is D, the diameter ratio d / D between the inlet and the outlet is 0.65, and the length of the expansion section 23 is 1.5D.

[0068] The top of the throat section 22 is fixedly connected to a hollow shaft 13, and the bottom of the hollow shaft 13 is connected to the top of the throat section 22. In this embodiment, the throat section 22 and the hollow shaft 13 are both arranged horizontally, and the hollow shaft 13 is arranged to intersect the throat section 22, and the axis of the throat section 22 is perpendicular to the axis of the hollow shaft 13. A connecting assembly is provided in the hollow shaft 13, and the runner 9 is coaxially rotatably connected to the hollow shaft 13 through the connecting assembly, that is, the axis of the runner 9 is perpendicular to the axis of the throat section 22. The blades at the lower part of the runner 9 extend into the throat section 22 from the connection between the hollow shaft 13 and the throat section 22. Specifically, the connecting assembly includes two bearing seats 8 symmetrically arranged on both sides of the runner 9, and the bearing seats 8 are fixedly connected to the hollow shaft 13. A connecting shaft 10 is coaxially fixedly inserted into the runner 9, and both ends of the connecting shaft 10 are rotatably connected to the corresponding bearing seats 8 through miniature bearings 11.

[0069] In this embodiment, the bearing seat 8 is slidably inserted into the hollow shaft 13, and the outer wall of the bearing seat 8 cooperates with the inner wall step of the hollow shaft 13. Plug screws 6 are inserted at both ends of the hollow shaft 13, and an internal thread is provided on the inner wall of the hollow shaft 13 near the end. The external thread of the plug screw 6 cooperates with the internal thread of the hollow shaft 13 to achieve a fixed connection between the plug screw 6 and the hollow shaft 13. The end of the plug screw 6 located in the hollow shaft 13 abuts against the bearing seat 8. A sealing gasket 7 is sleeved on the plug screw 6, and the sealing gasket 7 abuts between the plug screw 6 and the hollow shaft 13. A sleeve 12 is provided between the miniature bearing 11 and the bearing seat 8. Specifically, the sleeve 12 is installed in the bearing seat 8 in an interference fit manner, and the miniature bearing 11 is installed in the inner hole of the sleeve 12 in an interference fit manner.

[0070] The blades of the runner 9 are 15 mm long and 10 mm wide. The length of the blades at the lower portion of the runner 9 extending into the throat section 22 is ≥ 5 mm. Specifically, the length of the blades at the lower portion of the runner 9 extending into the throat section 22 can be 5 mm, 6 mm, 7 mm, etc.

[0071] The specific implementation process is as follows: The gas enters the housing of the flow meter from the pipeline and passes through the contraction section 21, throat section 22 and expansion section 23 of the housing in sequence.

[0072] When the gas passes through the contraction section 21, since the inner diameter of the contraction section 21 gradually decreases along the gas flow direction, the gas flow velocity can be accelerated, the kinetic energy can be increased, the pressure can be reduced, and the turbulence can be reduced.

[0073] When the gas passes through the throat section 22, it pushes the blades extending into the lower portion of the runner 9, thereby rotating the runner 9. Because the preceding contraction section 21 reduces turbulence, the gas reaches a maximum flow velocity and a stabilized flow field in the throat section 22, allowing the runner 9 installed in the throat section 22 to more accurately reflect the actual flow velocity of the gas.

[0074] The rotational speed of rotor 9 is proportional to the gas flow rate passing through it. Magnetoelectric sensor 3 detects this speed and generates a pulse signal that is sent to flow converter 4. The pulse signal output by magnetoelectric sensor 3 is amplified and filtered by two operational amplifiers before being sent to the microcontroller for flow calculation.

[0075] When the gas passes through the expansion section 23, the inner diameter of the expansion section 23 gradually increases along the flow direction of the gas, that is, the cross-sectional area gradually increases, which can restore part of the static pressure of the gas, thereby gradually slowing down the gas flow rate and minimizing the capacity loss and turbulence caused by sudden changes in flow rate, which helps to protect downstream equipment.

[0076] Example 2 A gas rotor flowmeter with rectification and acceleration function, as shown in the attached Figure 4 、 Figure 5 and Figure 6 As shown, the difference from Example 1 is that the cross section of the contraction section 21 is a curve, and the inlet diameter of the contraction section 21 is D n , the outlet diameter is D0, and the area ratio of the inlet and outlet of the contraction section 21 is 2.65. The length of the contraction section 21 is twice the inlet diameter, that is, the length of the contraction section 21 L = 2D n .

[0077] The cross-sectional curve of the contraction section follows the formula of the Delegated Sinski curve: ; Among them, R is the radius of any position of the contraction section, R0 is the radius of the contraction section outlet, R n is the radius of the inlet of the contraction section, X is the length from the inlet of the contraction section to any position, and L is the length of the contraction section.

[0078] The shape and size of the throat section 22 and the expansion section 23 are the same as those in the first embodiment.

[0079] Example 3 A gas rotor flowmeter with rectification and acceleration function, as shown in the attached Figure 7 As shown, the difference between it and embodiment 2 is that the shape and size of the expansion section 23 are the same as those of the contraction section 21, and the expansion section 23 and the contraction section 21 are symmetrically arranged at both ends of the throat section 22. Specifically, the inlet diameter of the expansion section 23 is D0, and the outlet diameter is D n The area ratio of the outlet and inlet of the expansion section 23 is 2.65. The length of the expansion section 23 is twice the outlet diameter, that is, the length of the expansion section 23 L = 2D n .

[0080] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A gas rotor flowmeter with a rectifying and accelerating function, comprising a housing and a rotor, a sensor disposed on top of the housing, a flow converter disposed on top of the sensor, the sensor and the flow converter being electrically connected; characterized in that: The shell includes a contraction section, a throat section and an expansion section which are arranged in sequence along the gas flow direction. The inner diameter of the contraction section gradually decreases along the gas flow direction to be equal to the inner diameter of the throat section, and the inner diameter of the expansion section gradually increases along the gas flow direction from being equal to the inner diameter of the throat section; a hollow shaft is provided at the top of the throat section, and the bottom of the hollow shaft is connected to the top of the throat section; a connecting assembly is provided in the hollow shaft, and the runner is rotatably connected to the hollow shaft through the connecting assembly, the axis of the runner is perpendicular to the axis of the throat section, and the blades at the lower part of the runner extend into the throat section from the connection between the hollow shaft and the throat section.

2. The gas rotary flowmeter with rectification and acceleration function according to claim 1, characterized in that: The connecting assembly includes bearing seats symmetrically arranged on both sides of the rotating wheel, and the bearing seats are fixedly connected to the hollow shaft; a connecting shaft is coaxially fixedly plugged into the rotating wheel, and both ends of the connecting shaft are rotatably connected to the corresponding bearing seats through miniature bearings.

3. The gas rotary flowmeter with rectification and acceleration function according to claim 2, characterized in that: The bearing seat is slidably inserted in the hollow shaft, and the outer wall of the bearing seat matches the inner wall step of the hollow shaft; screw plugs are inserted at both ends of the hollow shaft, the screw plugs match the hollow shaft threads, and the screw plugs abut against the bearing seat.

4. The gas rotary flowmeter with rectification and acceleration function according to claim 3, characterized in that: A sealing gasket is sleeved on the screw plug, and the sealing gasket abuts between the screw plug and the hollow shaft; And / or, a shaft sleeve is provided between the miniature bearing and the bearing seat.

5. The gas rotary flowmeter with rectification and acceleration function according to claim 1, characterized in that: The cross section of the contraction section is a straight line, the diameter ratio of the outlet and the inlet of the contraction section is 0.65, and the length of the contraction section is 1.5 times the diameter of the inlet.

6. The gas rotary flowmeter with rectification and acceleration function according to claim 1, characterized in that: The cross section of the contraction section is a curve, the area ratio of the inlet and outlet of the contraction section is 2.65, and the length of the contraction section is twice the diameter of the inlet; And the profile curve of the contraction section follows the entrusted Sinski curve formula: ； Among them, R is the radius of any position of the contraction section, R0 is the radius of the contraction section outlet, R n is the radius of the inlet of the contraction section, X is the length from the inlet of the contraction section to any position, and L is the length of the contraction section.

7. A gas rotary flowmeter with rectification and acceleration function according to claim 5 or 6, characterized in that: The diameter of the throat section is the same as the diameter of the outlet of the contraction section, and the length of the throat section is 0.8 times the diameter.

8. The gas rotary flowmeter with rectification and acceleration function according to claim 7, characterized in that: The shape and size of the expansion section are the same as those of the contraction section, and the expansion section and the contraction section are symmetrically arranged at both ends of the throat section.

9. The gas rotary flowmeter with rectification and acceleration function according to claim 1, characterized in that: The blade of the runner is 15 mm long and 10 mm wide; the length of the blade extending into the throat section is ≥5 mm.

10. A gas rotary flowmeter with rectification and acceleration function according to any one of claims 1 to 9, characterized in that: The flow converter includes a microcontroller and two operational amplifiers electrically connected to the microcontroller. The sensor is electrically connected to the two operational amplifiers. The pulse signal output by the sensor is amplified and filtered by the two operational amplifiers in turn and then transmitted to the microcontroller for flow calculation. And / or, the sensor is a magnetoelectric sensor.

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