An automatically continuously measuring high efficiency soap film flowmeter and method

Abstract

The present application relates to the technical field of soap film flowmeter, and provides a high-efficiency soap film flowmeter and method for automatic continuous measurement. The flowmeter comprises a soap solution pool, a film forming device, a soap solution collecting cup and a single-chip microcomputer. The soap solution pool is provided with an air inlet, and a soap film tube is vertically installed and provided with a photoelectric sensor for detecting a soap film passing signal. The film forming device comprises a film forming frame and a lifting mechanism, and the film forming frame is internally provided with a tapered channel which is wide at the bottom and narrow at the top, so that the soap film can be formed during lifting and transferred to the soap film tube by means of pressure difference. The soap solution collecting cup is provided with various sensors for detecting temperature, pressure and moisture content. The single-chip microcomputer receives signals of the sensors, automatically counts time and calculates the instantaneous flow of gas, and simultaneously performs state conversion and data output. The present application solves the problems of automatic generation, efficient transmission and accurate measurement of soap film under micro flow, significantly improves the reliability of micro flow measurement, and has the advantages of high film forming success rate, simple operation and wide applicability.

Description

Technical Field

[0001] This invention relates to the field of soap film flow meter technology, and provides an efficient soap film flow meter and method for automatic continuous measurement. Background Technology

[0002] An electronic soap film flow meter consists of a graduated soap film tube with an air inlet at the bottom. An aerator is located at the very bottom of the tube, containing soap solution. A photoelectric sensor and a display instrument are mounted on the outer wall of the soap film tube. During operation, gas enters the flow meter through the air inlet at the bottom of the soap film tube. The soap film generated by the aerator enters the tube through the inlet, adhering to the inner wall and completely isolating the airflow path. The pressure difference from the incoming air pushes the soap film upwards at a constant speed along the tube. When the soap film reaches the lower graduation mark, a timer starts; when it reaches the upper graduation mark, the timer stops. The instantaneous flow rate can be calculated from the measured time and the volume between the two graduation marks, and the display instrument directly shows the instantaneous flow rate.

[0003] However, traditional soap film flow meters have significant technical limitations when used in low-flow-rate measurement scenarios, such as flow calibration for instruments like gas chromatographs, VOCs samplers, and gas bag samplers. These limitations severely restrict their application, measurement accuracy, and reliability. In low-flow-rate applications, such as when the gas flow rate is below 50 mL / min, the success rate of soap film formation is generally low. Situations where the soap film is very difficult to form stably or ruptures immediately after formation are common, severely restricting and affecting the use and calibration of soap film flow meters. The root cause of this problem lies in several factors. First, under low flow conditions, the slow gas velocity and insufficient gas driving force cause the soap film to easily break upon contact at the inlet of the soap film tube, making it difficult to generate a soap film that meets the measurement requirements. The low gas flow rate is insufficient to provide a stable and powerful upward driving force for the soap film, causing it to break due to external forces during its formation or entry into the soap film tube. Second, the improper design of traditional foaming components and the lack of an effective pressure gradient control mechanism result in an unstable stress environment for the soap film during its initial formation stage, leading to deformed soap film formation or the formation of multiple soap films. Third, the difficulty of generating a soap film under low flow conditions using manual or semi-automatic film-forming methods further reduces the success rate of forming a soap film that meets the measurement requirements.

[0004] In low-flow-rate measurements, the soap film transfer efficiency is low. Under low-flow-rate conditions, the soap film moves slowly during transfer, significantly extending the single measurement cycle and severely impacting measurement efficiency. The main reasons for this low transfer efficiency include: firstly, traditional film-forming devices struggle to form a soap film at low flow rates, lacking an effective acceleration mechanism, and the soap film relies entirely on the weak pushing and pulling force of the gas flow to move slowly; secondly, the transition design between the film-forming structure and the transfer channel is unreasonable, making the soap film susceptible to resistance during transfer from the film-forming device to the measurement pipe, leading to breakage or stagnation; and thirdly, the lack of an automated lifting control mechanism makes it impossible to precisely control the soap film formation position and transfer timing, resulting in breakage and loss during transfer, indirectly extending measurement time and cycle.

[0005] Existing technologies still suffer from problems such as poor continuity of manual operation and frequent human intervention. Key steps such as film formation and transfer require manual control, which is even more difficult to grasp the optimal timing of operation under low flow conditions. Frequent manual operation not only increases the risk of soap film breakage, but also objectively limits the achievement of automatic continuous measurement.

[0006] Furthermore, when using soap film flow meters for flow measurement or calibration, it is generally necessary to take three measurements and average them to calculate the flow indication error, or take six measurements to calculate the flow repeatability error. Each measurement process requires manual operation, recording and calculating data, which is labor-intensive, time-consuming, and inefficient.

[0007] This invention addresses the aforementioned problems by proposing an efficient soap film flow meter and method for automatic continuous measurement, which is of great significance. Summary of the Invention

[0008] To address the problems existing in the background art, the present invention provides an automatic continuous measurement high-efficiency soap film flow meter, which is equipped with a soap solution tank, a film forming device, a soap solution collection cup, and a microcontroller, wherein:

[0009] The soap solution tank is equipped with an air inlet; the soap film tube is a vertical circular pipe installed above the soap solution surface, and the upper part of the soap film tube is connected to the soap solution collection cup; the soap film tube has an upper scale line and a lower scale line, and photoelectric sensor I and photoelectric sensor II are respectively installed on both sides of the lower scale line and the upper scale line; photoelectric sensor I and photoelectric sensor II detect the time when the soap film passes through and transmit the signal to the microcontroller; the soap solution collection cup is set on the air outlet of the soap film tube to collect broken soap film liquid and prevent broken soap liquid from flowing back into the soap film tube and affecting the normal operation of the photoelectric sensors.

[0010] The film-forming device includes a film-forming frame, which is installed between the soap film tube and the soap solution pool. The film-forming frame has a tapered channel with openings at both ends and a wider bottom and narrower top. The width of the tapered channel is greater than the diameter of the soap film tube. The film-forming frame is connected to a lifting mechanism, which drives the film-forming frame to rise and fall, generating a soap film in the tapered channel and transferring it to the soap film tube.

[0011] In a preferred embodiment, the conical channel is a circular conical channel or a pyramidal channel.

[0012] In a preferred embodiment, the lifting mechanism includes a linear driver, a fixed plate, and a push-pull rod; the film lifting frame is connected to the push-pull rod, and the push-pull rod is connected to the linear driver through the fixed plate, so that the linear driver drives the push-pull rod, the fixed plate, and the film lifting frame to rise and fall.

[0013] In the preferred embodiment, the push-pull rod is fixed to the fixing plate by a hexagonal nut.

[0014] In the preferred embodiment, the soap liquid collection cup is provided with several connection channels, and temperature sensors, pressure sensors, and moisture content sensors that are connected to the microcontroller are respectively installed in the several connection channels.

[0015] In a preferred embodiment, the soap liquid collection cup is provided with an air outlet, and the air outlet of the soap liquid collection cup is connected to a drying bottle.

[0016] In the preferred embodiment, the microcontroller is connected to an atmospheric pressure sensor, an ambient temperature sensor, a display screen, and a keyboard.

[0017] This invention also provides a method for using an automatic continuous measurement high-efficiency soap film flow meter, comprising the following steps:

[0018] S1, the microcontroller controls the linear driver to work, which drives the push-pull rod to descend through the fixed plate. The push-pull rod drives the film-forming frame to descend and move to the soap solution pool where the lower end of the soap film tube is located. The bottom surface of the film-forming frame descends to below the soap solution level in the soap solution pool. The soap solution pool is kept connected to the gas source, and gas continuously enters the upper part of the soap solution pool through the air inlet.

[0019] S2, the linear actuator drives the push-pull rod and the film-forming frame to rise. When the film-forming frame detaches from the upper liquid surface of the soap solution, a soap film is formed at the bottom of the film-forming frame. Since the inside of the film-forming frame is a conical channel that is open at both ends and wider at the bottom than at the top, there is a pressure difference between the upper and lower surfaces of the soap film after the film-forming frame detaches from the upper liquid surface of the soap solution. Under the action of the pressure difference between the upper and lower surfaces, the soap film moves from bottom to top. Moreover, the movement is accelerated, and the closer it is to the top of the conical channel, the faster the movement speed.

[0020] S3, during this process, the linear actuator continues to drive the push-pull rod and the film-forming frame to rise. When the upper part of the tapered channel of the film-forming frame passes through the bottom of the soap film tube, the soap film in the tapered channel accelerates and moves to the gas inlet of the soap film tube under the action of the pressure difference, and is smoothly pushed into the soap film tube. The soap film in the soap film tube continues to rise along the soap film tube under the action of the flowing gas until it moves to the upper end of the soap film tube and enters the soap liquid collection cup.

[0021] S4, as the soap film moves from bottom to top in the soap film tube, when the soap film passes photoelectric sensor I, photoelectric sensor I transmits the detected signal to the microcontroller, and the microcontroller's timer starts counting; when the soap film continues to move to photoelectric sensor II, photoelectric sensor II transmits the signal to the microcontroller, and the timing stops.

[0022] S5, the microcontroller calculates the volumetric flow rate of gas flowing through the soap film flowmeter based on the movement time of the soap film from photoelectric sensor I to photoelectric sensor II, the volume value between the two scale lines of the soap film tube; the microcontroller displays the data measured by the temperature sensor, pressure sensor, moisture content sensor, atmospheric pressure sensor, and ambient temperature sensor, and performs flow rate conversion under different conditions; it calculates the flow rate under different temperature and pressure conditions (e.g., the standard flow rate under the conditions of 20℃ temperature and 101.325kPa pressure).

[0023] S6 utilizes a combination of microcontroller, linear driver, and photoelectric sensor to achieve programmed automatic control of the number of times the flow rate value is measured.

[0024] The beneficial effects achieved by this invention are as follows:

[0025] This invention, through its unique conical channel design and pressure differential driving mechanism, effectively overcomes the bottlenecks of traditional methods, such as easy rupture of soap films, formation of deformed soap films, and difficulties in film formation under low gas flow conditions. It significantly improves stability and integrity, ensuring reliability in low flow rate measurements, reducing errors and measurement time, and increasing work efficiency. This invention automatically completes the formation, transfer, and flow rate calculation of the soap film. Especially when handling low flow rates, it avoids errors and uncertainties that may be caused by complex manual operations, ensuring measurement consistency and accuracy. The advantages of this invention are also applicable to the use of high-flow-rate soap film flow meters.

[0026] This invention can also achieve automatic and continuous flow measurement through program control.

[0027] Specifically, this manifests in:

[0028] First, this invention designs a film-forming frame and a lifting mechanism. The conical channel inside the film-forming frame has a structure that is wider at the bottom and narrower at the top. After the film-forming frame detaches from the soap solution surface, a soap film is formed. Under the pressure difference between the upper and lower surfaces of the soap film within the conical channel, the soap film automatically accelerates towards the direction with the smaller taper diameter, further improving the quality of the soap film that meets the measurement requirements, significantly shortening the film formation time, and increasing the transfer efficiency. The conical or frustum-shaped structure of the conical channel allows the soap film to accelerate under the drive of the pressure difference, with the speed increasing as it approaches the top of the channel. This progressively accelerating motion significantly improves the efficiency and success rate of transferring the soap film to the measuring pipe. The lifting mechanism consists of a linear actuator, a push-pull rod, and a fixed plate. By precisely controlling the lifting movement of the film-forming frame, the stability of soap film formation and transfer is ensured, avoiding the risk of soap film breakage in traditional manual operation. This innovative device directly translates into a highly efficient film formation process, reducing and minimizing the impact of external interference, and enhancing the reliability and ease of use of the system.

[0029] Secondly, this invention integrates photoelectric sensor I and photoelectric sensor II, mounted on both sides of the lower and upper scale lines of the soap film tube. When the soap film passes through, it automatically detects the signal and transmits it to the microcontroller, achieving complete automation of the timing measurement process, eliminating human timing errors, and improving the accuracy of time measurement. The temperature sensor, pressure sensor, and humidity sensor installed in the soap liquid collection cup, combined with external atmospheric pressure and ambient temperature sensors, provide the microcontroller with comprehensive environmental parameter data. This provides technical support for the conversion of flow state under different temperature, humidity, and pressure conditions, expanding the functionality of the soap film flow meter and significantly improving the accuracy and adaptability of flow calculation, ensuring reliable measurement results under various operating conditions.

[0030] Third, this invention designs an efficient film formation and measurement method. The lifting and lowering movement of the film-forming frame in the soap solution pool is controlled by a microcontroller. The process from soap film formation to transfer to the soap film tube is efficiently connected. The accelerated movement inertia of the soap film in the conical channel ensures that it smoothly enters the soap film tube for normal measurement, which improves the film formation speed and measurement continuity, and enhances the repeatability and consistency of the measurement. It is more suitable for high-frequency or complex environment application scenarios.

[0031] Fourth, automatic continuous flow measurement can be achieved through program control, saving manpower and improving work efficiency. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the soap film formation process. Figure 1 ;

[0034] Figure 3This is a schematic diagram of the soap film formation process. Figure 2 ;

[0035] Figure 4 This is a schematic diagram of the soap film formation process. Figure 3 ;

[0036] Figure 5 This is a schematic diagram of the soap film formation process. Figure 4 .

[0037] Numbering on the map:

[0038] 1. Air inlet; 2. Soap solution tank; 3. Soap film tube; 301. Photoelectric sensor II; 302. Photoelectric sensor I; 4. Soap solution collection cup; 5. Temperature sensor; 6. Pressure sensor; 7. Moisture content sensor; 8. Air outlet; 9. Drying bottle; 10. Microcontroller; 11. Film raising frame; 12. Push-pull rod; 13. Hex nut; 14. Fixing plate; 15. Cross-head pan head screw; 16. Linear actuator; 17. Atmospheric pressure sensor; 18. Ambient temperature sensor; 19. Display screen; 20. Keyboard. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Reference Figures 1-5 This invention provides an automatic continuous measurement high-efficiency soap film flow meter and method, including core components such as a soap solution tank 2, a soap film tube 3, a film forming device, a soap solution collection cup 4, and a microcontroller 10. The soap solution tank 2 is the basic component of the entire system, which stores the soap solution used to form the soap film. The soap solution tank 2 is provided with an air inlet 1, which is connected to the atmosphere, allowing air to continuously enter the soap solution tank 2 through the air inlet 1, providing the necessary airflow conditions for subsequent soap film formation and flow measurement.

[0041] The soap film tube 3 is a key component for flow measurement. It is a vertical circular pipe installed above the soap solution surface. The upper part of the soap film tube 3 is connected to the soap solution collection cup 4, forming a complete fluid channel. The soap film tube 3 has upper and lower graduation lines. The distance between these two graduation lines and the cross-sectional area of ​​the pipe determine the volume value used for flow calculation. Photoelectric sensor I 302 and photoelectric sensor II 301 are installed on both sides of the lower and upper graduation lines, respectively. The function of these two photoelectric sensors is to detect the precise moment when the soap film passes through. After detecting the soap film passage signal, photoelectric sensor I 302 and photoelectric sensor II 301 transmit the signal to the microcontroller 10, realizing the automation and accuracy of time measurement.

[0042] The film-forming device is the core component of this flowmeter, including a film-raising frame 11 and a lifting mechanism. The film-raising frame 11 is installed between the soap film tube 3 and the soap solution tank 2. It has a conical channel inside, open at both ends and wider at the bottom than at the top. The width of this conical channel is greater than the diameter of the soap film tube 3, facilitating the entry of the soap film into the soap film tube 3 along the conical channel. Inside the conical channel, the soap film accelerates upward under the action of the pressure difference and is smoothly pushed into the soap film tube 3, significantly improving the film formation success rate, reducing measurement time, and increasing the efficiency of the measurement work. The conical channel can be a circular conical channel or a pyramidal channel, providing flexible choices for different application requirements.

[0043] The lifting mechanism includes a linear actuator 16, a fixed plate 14, and a push-pull rod 12. A film-lifting frame 11 is connected to the push-pull rod 12, which is connected to the linear actuator 16 via the fixed plate 14. The linear actuator 16 drives the push-pull rod 12, the fixed plate 14, and the film-lifting frame 11 to rise and fall, achieving precise automated control of the film-forming process. The push-pull rod 12 and the fixed plate 14 are secured with hexagonal nuts 13, ensuring a strong and reliable connection. The fixed plate 14 is also secured with Phillips head screws 15, further enhancing the stability of the entire lifting mechanism.

[0044] The soap liquid collection cup 4 is located at the upper end of the soap film tube 3. It is used to collect the soap film after the measurement task is completed, preventing the soap film from breaking and flowing back into the soap film tube, which would affect the normal operation of the photoelectric sensor. The soap liquid collection cup 4 is provided with several connection channels, in which temperature sensor 5, pressure sensor 6, and moisture content sensor 7 are respectively installed, which are connected to the microcontroller 10. Temperature sensor 5 is used to measure the temperature of the gas passing through the flow meter, pressure sensor 6 measures the gas pressure, and moisture content sensor 7 measures the humidity content of the gas. They provide data support for flow measurement and gas flow conversion under different conditions. The soap liquid collection cup 4 is provided with an outlet 8, which is connected to a drying bottle 9. The function of drying bottle 9 is to remove moisture and broken soap film from the gas path, preventing them from affecting subsequent equipment and improving the reliability and accuracy of the measurement.

[0045] The microcontroller 10 is the core of the entire system's control and calculation. Signal connections also include an atmospheric pressure sensor 17, an ambient temperature sensor 18, a display screen 19, and a keyboard 20. The atmospheric pressure sensor 17 measures the ambient atmospheric pressure, and the ambient temperature sensor 18 measures the ambient temperature. The display screen 19 displays the calculated instantaneous flow rate, temperature, pressure, and other data, providing users with intuitive measurement results. The keyboard 20 provides the user interface for setting measurement parameters and controlling system operation.

[0046] This invention, through its conical channel pressure gradient design and automatic lifting control mechanism, effectively reduces soap film breakage and the formation of deformed soap films, shortens measurement time, and solves the problems of low film formation success rate and poor transfer efficiency.

[0047] The tapered channel's wider-than-narrow structure is based on surface tension and fluid dynamics. When the film-forming frame rises from the soap solution and detaches from the surface, the tapered channel facilitates soap film formation. Surface tension causes the soap film to have a certain tendency to contract, and the geometric constraint of the tapered channel automatically transforms this contractile force into an upward driving force, thus increasing the success rate of soap film formation. Specifically, the soap film forms a curved interface in the tapered channel. According to the Young-Laplace equation, there is a pressure difference ΔP = γ(1 / R1 + 1 / R2) across the curved interface, where γ is the surface tension coefficient. In the case of a conical interface, the soap film interface in the tapered channel is as follows:

[0048] R1 (radial radius of curvature) is the radius of curvature of the soap film in the radial direction (in a plane perpendicular to the axis). Due to surface tension, the soap film will form an inwardly curved arc cross-section. The value is usually positive and its magnitude depends on surface tension, pressure difference, and channel radius.

[0049] R2 (axial radius of curvature) is the radius of curvature of the soap film in the axial direction (along the channel axis). In an ideal frustum channel, if the soap film remains relatively straight along the axial direction, R2 tends to infinity. Due to the influence of gravity and pressure gradient, the soap film may exhibit slight axial curvature. In a conical channel, ΔP mainly contributes from the radial curvature: ΔP≈γ / R1.

[0050] This is because the axial curvature is relatively small and varies along the height direction; due to the taper of the frustum, R1 changes at different heights. The narrower the channel, the smaller R1 and the larger the pressure difference ΔP; thus, a pressure gradient is formed along the axial direction. For a conical channel, the bottom diameter is large, R1 is large, and ΔP is small; the top diameter is small, R1 is small, and ΔP is large; pressure gradient = ΔP_top - ΔP_bottom > 0; this pressure gradient is the driving force that propels the soap film upward.

[0051] The tapered channel's tapered design cleverly utilizes the directional characteristics of surface tension. In the channel, which is wider at the bottom and narrower at the top, the radius of curvature of the soap film decreases as the channel cross-section shrinks. According to the principle of surface tension, this smaller radius of curvature generates a pressure difference. This pressure gradient increases from the bottom to the top of the channel, providing a continuous upward thrust for the soap film. Simultaneously, the tangential component of the surface tension forms an upward resultant force on the tapered wall, further enhancing the upward driving force of the soap film. This intrinsic driving mechanism based on surface tension can push the soap film into the soap film tube 3 without relying on weak external airflow thrust, making it particularly suitable for soap film transfer in low-flow-rate scenarios.

[0052] The conical channel structure also achieves self-accelerating motion of the soap film through the surface tension effect. As the soap film moves upward in the channel, the surface area of ​​the soap film decreases accordingly due to the gradual reduction in the channel cross-section. The energy released from this decrease in surface energy is converted into kinetic energy, causing the soap film to exhibit accelerated upward movement. The closer to the top of the channel, the greater the cross-sectional contraction rate, and the more pronounced the acceleration effect. This surface tension-driven acceleration mechanism significantly improves the soap film transfer efficiency, solves the technical problem of slow soap film movement under low flow conditions, reduces flow measurement time, and improves work efficiency.

[0053] Furthermore, the surface tension control mechanism of the conical channel enhances the stability of the soap film. Under low flow conditions, soap films in traditional straight channels are prone to breakage due to gravity and minor external disturbances. The radial compressive force generated by the surface tension in the conical channel acts like a surface tension support for the soap film, maintaining its relatively stable shape during ascent and significantly improving the film formation success rate. This self-stabilizing characteristic of surface tension enables the soap film to resist minor pressure fluctuations and mechanical vibrations, ensuring high-quality soap film formation that is less prone to breakage during low flow measurement, and also preventing the formation of multiple continuous or deformed soap films.

[0054] Precise lifting mechanism control ensures accurate timing of soap film formation and a smooth transition during the transfer process. The linear actuator, through program control, precisely positions the film-forming frame, ensuring the soap film forms under optimal surface tension, thus avoiding film formation failures caused by improper timing control during manual operation. Precise control of the lifting speed allows the soap film to smoothly transition into the soap film tube under surface tension, avoiding impacts and disturbances during transfer.

[0055] Multi-sensor integration and microcontroller-based automated control enable one or more measurement processes to be performed without human intervention. The system can automatically adjust film formation and transfer parameters based on real-time environmental parameters, optimizing the surface tension effect. Data from temperature and pressure sensors are used to correct the surface tension coefficient in real time, ensuring the accuracy of the pressure gradient calculation in the conical channel. Automated control eliminates the uncertainties of manual operation, enabling the surface tension driving mechanism to function stably and significantly improving the success rate and efficiency of micro-flow rate measurements.

[0056] Through the above-mentioned tapered channel design based on the principle of surface tension and the automated control mechanism, this invention achieves stable formation, efficient transfer and accurate measurement of soap film under low flow conditions, providing a reliable technical solution for low flow measurement.

[0057] The working process of this invention is as follows: The microcontroller 10 controls the linear driver 16 to work, which drives the push-pull rod 12 to descend through the fixing plate 14. The push-pull rod 12 drives the film-forming frame 11 to descend and move into the soap solution pool 2 where the lower end of the soap film tube 3 is located; the bottom surface of the film-forming frame 11 descends to below the soap solution surface of the soap solution pool 2 (e.g., ...). Figure 2 (As shown); keep the soap solution tank 2 connected to the gas source, and continuously allow gas to enter the soap solution tank 2 through the air inlet 1; the linear actuator 16 drives the push-pull rod 12 and the film-forming frame 11 to rise, and when the film-forming frame 11 detaches from the upper liquid surface of the soap solution, a soap film is formed at the bottom of the film-forming frame 11 (as shown). Figure 3 (As shown); because the film-forming frame 11 has a conical channel that is open at both ends and wider at the bottom than at the top, when the film-forming frame 11 detaches from the upper surface of the soap solution, there is a pressure difference between the upper and lower surfaces of the soap film. Under the action of the pressure difference between the upper and lower surfaces, the soap film moves from bottom to top; and the movement is an accelerated movement, the closer to the top of the conical channel, the faster the movement (as shown). Figure 4 (As shown); During this process, the linear actuator 16 continues to drive the push-pull rod 12 and the film-forming frame 11 to rise. When the upper part of the conical channel of the film-forming frame 11 passes through the bottom of the soap film tube 3, the soap film in the conical channel, under the action of the pressure difference, accelerates and moves to the gas inlet of the soap film tube 3, and is smoothly pushed into the soap film tube 3 (as shown). Figure 5 As shown in the figure, the soap film continues to rise along the soap film tube 3 under the action of the flowing gas; until it moves to the upper end of the soap film tube 3 and enters the soap liquid collection cup 4.

[0058] To ensure the integrity of the soap film upon entering the soap film tube and prevent breakage, the microcontroller 10 precisely controls the rising speed of the linear actuator 16. This control strategy is based on pre-stored characteristic curves of the soap film accelerating upward within the conical channel under different gas flow rates, soap solution characteristics, and conical channel geometry parameters. The microcontroller 10, based on the current gas flow rate and environmental parameters detected in real time by temperature sensor 5, pressure sensor 6, humidity sensor 7, atmospheric pressure sensor 17, and ambient temperature sensor 18, retrieves the expected rising speed of the soap film driven by pressure difference within the conical channel from its built-in database or calculates it in real time using algorithms. Based on this, it adjusts the output of the linear actuator 16, causing it to drive the film-raising frame 11 to rise synchronously at a rate matching or slightly lower than the soap film's rising speed. This refined synchronous control ensures that the film-raising frame 11 continuously provides structural support for the soap film during the smooth pushing of the soap film to the inlet of the soap film tube 3, preventing premature breakage due to the film film detaching from support due to excessively rapid rising of the frame, or decreased stability due to excessively slow rising hindering the accelerated movement of the soap film. Through this refined speed matching mechanism, the present invention significantly improves the success rate and stability of soap film delivery, especially exhibiting excellent anti-breakage performance under low flow conditions.

[0059] As the soap film moves upwards within the soap film tube 3, when it passes photoelectric sensor I 302, the sensor transmits the detected signal to the microcontroller 10, and the microcontroller 10's timer starts counting. When the soap film continues to move to photoelectric sensor II 301, the sensor transmits a signal to the microcontroller 10, and the timer stops. The microcontroller 10 calculates the volumetric flow rate of the gas flowing through the soap film flowmeter based on the movement time of the soap film from photoelectric sensor I 302 to photoelectric sensor II 301 and the volume value between the two scale lines of the soap film tube 3. The microcontroller 10 combines the data measured by temperature sensor 5, pressure sensor 6, moisture content sensor 7, atmospheric pressure sensor 17, and ambient temperature sensor 18 to perform flow rate conversion under different conditions. The calculated volumetric flow rate, temperature, and pressure data are displayed on the display screen 19, and the user can perform related operation settings via the keyboard 20.

[0060] Example 1 describes the automatic and continuous measurement of a gas flow rate of 1 mL / min, performed 6 times, and automatically calculating the average of the 6 measurements. It details the complete usage method of the high-efficiency soap film flow meter with automatic continuous measurement, demonstrating how precise automated control achieves both efficient film formation and accurate measurement.

[0061] S1, the operator sets the measurement count to 6, and the program starts automatic measurement: First, the microcontroller starts the linear driver 16, which drives the push-pull rod 12 to begin descending through the fixed plate 14. During the descent, the push-pull rod 12 drives the film-forming frame 11 to descend synchronously. The film-forming frame 11 gradually moves from the initial position to the lower end of the soap film tube 3, at which point the film-forming frame 11 is completely inside the soap solution tank 2. The film-forming frame 11 continues to move downward under the drive of the linear driver 16 until it is completely below the soap solution surface in the soap solution tank 2, so that the conical channel of the film-forming frame 11 is completely submerged in soap solution. Throughout the descent process, the system maintains the connection between the soap solution tank 2 and the gas source. The gas source continuously enters the soap solution tank 2 through the air inlet 1. In this embodiment, the gas flow rate of the gas source is about 1 mL / min, which belongs to the micro-flow measurement scenario.

[0062] S2, the linear actuator 16 changes its direction of motion, initiating an upward movement of the push-pull rod 12 and the film-forming frame 11. As the film-forming frame 11 rises and just detaches from the upper surface of the soap solution, a complete soap film naturally forms at its bottom due to surface tension. Because the film-forming frame 11 has an internal conical channel that is open at both ends and wider at the bottom than at the top, this unique geometry creates a significant pressure difference between the upper and lower surfaces of the soap film after it completely detaches from the upper surface. Driven by this pressure difference, the soap film begins to move upwards, exhibiting an accelerating movement characteristic; that is, the closer to the top of the conical channel, the faster the soap film moves. This acceleration effect significantly improves the efficiency of the soap film's upward transfer.

[0063] S3, the linear actuator 16 continues to maintain the upward movement of the push-pull rod 12 and the film-forming frame 11. When the film-forming frame 11 continues to rise until the upper part of its conical channel completely passes through the bottom of the soap film tube 3, the soap film originally located in the conical channel smoothly enters the internal space of the soap film tube 3 under the action of pressure difference. Under the action of flowing gas, the soap film moves upward along the soap film tube 3, continuously rising until it finally reaches the upper end of the soap film tube 3, and finally enters the soap liquid collection cup 4 connected to the upper part of the soap film tube 3, completing the entire process from film formation to transfer.

[0064] S4. When the soap film begins its upward movement within the soap film tube 3, the measurement system begins to function. When the moving soap film first passes the photoelectric sensor I 302 located at the lower scale line, the photoelectric sensor I 302 immediately detects the change in the optical signal as the soap film passes through and quickly transmits this detected signal to the microcontroller 10, which is the core of the system control. Upon receiving the signal, the microcontroller 10 immediately starts its built-in high-precision timer to begin precise timing. As the soap film continues to move upward along the soap film tube 3 and reaches the upper scale line, the photoelectric sensor II 301, installed at that position, also detects the change in the signal as the soap film passes through and immediately transmits this signal to the microcontroller 10. Upon receiving the signal from the photoelectric sensor II 301, the microcontroller 10 immediately stops the timer, thus obtaining precise time data on the movement of the soap film between the two photoelectric sensors.

[0065] S5, the microcontroller 10 begins performing complex flow calculations and data processing. Based on the measured precise movement time of the soap film between photoelectric sensor I 302 and photoelectric sensor II 301, and combined with the pre-calibrated volumetric value data between the two scale lines of the soap film tube 3, the microcontroller 10 calculates the instantaneous volumetric flow rate of the gas flowing through the soap film flowmeter using its built-in flow calculation method. To ensure the accuracy and applicability of the measurement results, the microcontroller 10 also comprehensively processes gas temperature data measured by temperature sensor 5, gas pressure data measured by pressure sensor 6, gas humidity data measured by moisture content sensor 7, ambient atmospheric pressure data measured by atmospheric pressure sensor 17, and ambient temperature data measured by ambient temperature sensor 18. It performs flow rate conversion and compensation calculations under different temperature and pressure conditions using built-in state equations and correction algorithms. The instantaneous flow rate data, temperature data, pressure data, and other important measurement parameters obtained after complete calculation and processing are clearly displayed on the connected display screen 19, providing operators with intuitive and accurate measurement results. Simultaneously, users can perform related parameter settings and system control operations via the keyboard 20.

[0066] S6, when the soap film passes the upper scale position on the soap film tube 3, the photoelectric sensor II 301 detects the signal of the soap film passing through, and the first flow rate measurement is completed. After that, the microcontroller automatically controls the linear driver 16 to start the second flow rate measurement... and so on, measuring 6 times and recording the measurement data each time.

[0067] S7, the microcontroller calculates the average flow rate by averaging the data from 6 measurements.

[0068] The implementation process of the usage method in this embodiment demonstrates the significant advantages of the high-efficiency film-forming soap film flow meter, including high automation, high film-forming efficiency, high film-forming success rate, simple operation, labor saving, and high measurement efficiency. Through the organic combination of precise mechanical control and advanced electronic measurement technology, high efficiency and high accuracy of soap film flow measurement are achieved, providing a reliable technical solution for various gas flow measurement applications.

[0069] Example 2 illustrates an application of automated continuous calibration of a VOCs sampler with a low flow rate. In an environmental monitoring station, to ensure the accuracy of VOCs sampling results in the ambient air, a sampling pump used for personal sampling needs periodic flow rate calibration. This pump requires a stable flow rate of 20 mL / min, and the calibration accuracy must be maintained under varying ambient temperatures and pressures. This example provides an efficient solution for this application scenario.

[0070] Example 2 utilizes the high-efficiency soap film flow meter with automatic continuous measurement described in this invention. The specific configuration includes a soap solution tank, a soap film tube equipped with photoelectric sensors I and II, a 10mL volume space between the two graduation lines, a film-raising frame with a tapered channel (wider at the bottom and narrower at the top), a lifting mechanism driven by a linear actuator, a soap solution collection cup integrating a temperature sensor, a pressure sensor, and a moisture content sensor, and a microcontroller connected to an atmospheric pressure sensor, an ambient temperature sensor, a display screen, and a keyboard. The calibration process is as follows:

[0071] The operator inputs the calibration flow rate of 20 mL / min and the number of calibrations of 5 via keyboard 20. After receiving the instruction, the microcontroller 10 starts the automatic calibration program.

[0072] The microcontroller 10 first controls the linear actuator 16 to lower the membrane holder 11, immersing it completely in the soap solution in the soap solution tank 2. The air source, the sampling pump, provides a stable airflow of 20 mL / min through the flow controller, continuously entering the area above the soap solution tank 2 via the air inlet 1.

[0073] The linear actuator 16 then drives the film-forming frame 11 to rise at a preset rate that matches the expected rising speed of the soap film. When the film-forming frame 11 detaches from the soap solution surface, a stable soap film is rapidly formed at the bottom of the conical channel. Under the pressure difference of the conical channel, the soap film accelerates upward and is smoothly pushed into the soap film tube 3.

[0074] After entering the soap film tube 3, the soap film continues to rise under the impetus of the airflow. When the soap film passes through photoelectric sensor I 302 and photoelectric sensor II 301 in sequence, the two sensors transmit the detection signals to the microcontroller 10. The microcontroller 10 automatically starts and stops the built-in high-precision timer to accurately record the time required for the soap film to pass through a 10mL volume.

[0075] The microcontroller 10 calculates the original volumetric flow rate based on the measured time and the volume of the soap film tube. Simultaneously, the microcontroller 10 reads real-time data from the temperature sensor 5, pressure sensor 6, and moisture content sensor 7 in the soap collection cup, as well as from the external atmospheric pressure sensor 17 and ambient temperature sensor 18. Using these environmental parameters, the microcontroller 10 compensates for and converts the original volumetric flow rate according to standard gas laws (such as the ideal gas law), calculating the standard flow rate value under standard conditions, such as 20°C and 101.325 kPa.

[0076] After completing one measurement and calculation, the microcontroller 10 automatically controls the film lifting frame 11 to reset and start the next measurement, and so on for 5 times.

[0077] All five standard flow rate measurements and related environmental parameters are displayed in real time on screen 19, and the average standard flow rate of the five measurements is automatically calculated. Operators can easily view the deviation between the average value and the target value of 20 mL / min, thereby completing the calibration of the VOCs sampling pump.

[0078] Comparative Example 1: This comparative example uses a traditional, fully manually operated glass soap film flow meter. The operator manually generates the soap film by squeezing the foaming bulb and visually times the time required for the soap film to pass the upper and lower scale marks using a high-precision stopwatch with a resolution of 0.01 seconds. This flow meter lacks any automated control, built-in environmental sensors, or automatic status conversion functions. After each measurement, the operator needs to manually record the data and manually calculate the flow rate.

[0079] Comparative Example 2: This comparative example simulates a soap film flow meter with partial automation. It integrates a linear actuator to achieve automatic soap film generation and raising / lowering, and is equipped with a photoelectric sensor for automatic timing. However, it lacks the unique bottom-wide, top-narrow conical channel design of this invention, instead employing a traditional flat-bottomed or straight-cylinder film-forming structure. Furthermore, the soap liquid collection cup only integrates a temperature sensor, lacking a pressure sensor, a moisture content sensor, and external atmospheric pressure and ambient temperature sensors. Therefore, this device can only perform flow correction based on temperature and cannot perform comprehensive temperature, pressure, and humidity state conversions.

[0080] Three comparative experiments were conducted for Example 2 and Comparative Examples 1 and 2, respectively targeting film formation rate and measurement continuity, time measurement accuracy, and flow rate calculation accuracy and adaptability.

[0081] The experimental standards include: JJG632-2011 "Verification Procedure for Soap Film Flow Meters": providing a basis for the verification methods and technical requirements of soap film flow meters; ISO6144:2005 "Gas analysis—Calibration of flow meters using soap film flow meters": providing methods for calibrating flow meters using soap film flow meters and defining standard conditions; and GB / T13866-2009 "Humidity Sensing Elements and Humidity Sensors for Measurement and Control Apparatus in Industrial Processes": providing a reference for the performance evaluation of humidity sensors.

[0082] The experimental equipment and materials included the high-efficiency soap film flow meter with automatic continuous measurement according to the present invention (Example 2), a conventional manual soap film flow meter (Comparative Example 1), and a simplified automated soap film flow meter (Comparative Example 2).

[0083] A high-precision piston-type flow standard, such as the BIOSDefender 510 (nominal accuracy better than ±1%), serves as a reference for the true flow rate. This standard has its own temperature and pressure sensors and can output a standard flow rate value. A high-precision stopwatch (used for Comparative Example 1, resolution 0.01s). Clean, dry air or high-purity nitrogen is used as the test gas. An environmental chamber / temperature, humidity, and pressure control system is used to simulate and maintain different environmental conditions.

[0084] Comparative Experiment 1: Verification of Film Formation Speed ​​and Measurement Continuity; Experimental Objective: To verify the ability of this invention to achieve efficient and continuous film formation and rapid measurement under low flow rates.

[0085] Experimental methods:

[0086] The three flow meters used in Example 2, Comparative Example 1, and Comparative Example 2 were connected in series with a high-precision piston flow standard. The piston flow standard was set to output a stable gas flow rate of 20 mL / min. All experiments were conducted in a controlled laboratory environment with an ambient temperature of 25 ± 1°C, an atmospheric pressure of 101.3 ± 1 kPa, and a relative humidity of 50 ± 5%.

[0087] Example 2: Start the equipment and set it to automatic continuous measurement mode, taking 10 measurements. Record the time from the start of the film-forming frame rising to the point where the soap film smoothly enters the soap film tube (defined as "film formation and transfer time"), and the total time for completing 10 measurements and automatically calculating the average value.

[0088] Comparative Example 1: The operator manually attempts to generate a soap film and measures it 10 times. The film-forming transfer time (from manually squeezing the foaming ball to the soap film entering the soap film tube) and measurement time are recorded for each attempt. The number of successful attempts and the number of failures are also recorded. After each failure, the attempt is repeated.

[0089] Comparative Example 2: Start the device, set it to automatic continuous measurement mode, and perform 10 measurements. Record the film transfer time and the total time to complete 10 measurements and automatically calculate the average value, and record the number of successful measurements.

[0090] Experimental indicators and data:

[0091] Average single measurement cycle (s / time): The average time from the start of one measurement to the start of the next measurement (including film formation, rise, timing, calculation and reset).

[0092] Film formation success rate (%): The percentage of soap films successfully formed and entered the soap film tube out of the total number of attempts.

[0093] Single film transfer time (s): The time from the rise of the film-forming frame (or the extrusion of the foaming ball) to the smooth entry of the soap film into the soap film tube.

[0094] Table 1 Comparison of film formation rate and measurement continuity

[0095]

[0096] As shown in Table 1, Example 2 of the present invention significantly outperforms Comparative Example 1 (traditional manual soap film flow meter) and Comparative Example 2 (simple automated soap film flow meter) in terms of average single measurement cycle, film formation success rate, and single film formation transfer time. Example 2 achieves a 100% film formation success rate and has the shortest single film formation transfer time (only 3.2 seconds) and the shortest average single measurement cycle (18.5 seconds). This indicates that the present invention, through its unique conical channel design and automated lifting mechanism, effectively overcomes the bottlenecks of traditional methods, such as easy breakage of soap films and difficulty in film formation under low gas flow conditions, significantly improving the stability and integrity of the film formation, thereby achieving the beneficial effects of improved film formation speed and measurement continuity. Comparative Example 1 suffers from low film formation success rate due to the randomness of manual operation and the defects of traditional film formation structures, and the measurement cycle is significantly prolonged due to frequent retries. Although Comparative Example 2 has automated functions, it lacks the acceleration mechanism of the conical channel, and its film formation efficiency and success rate are still lower than those of the present invention.

[0097] Comparative Experiment 2: Verification of the accuracy of time measurement; Experimental objective: To verify the advantages of the photoelectric sensor of this invention in terms of the accuracy of time measurement.

[0098] Experimental methods:

[0099] Example 2 and Comparative Example 1 were respectively connected to a high-precision piston-type flow standard, with the flow rate set to a stable 20 mL / min. Environmental conditions were the same as in Comparative Experiment 1. Example 2: The equipment was started for 10 consecutive measurements. The microcontroller automatically recorded the time interval between each passage of the soap film through photoelectric sensors I and II. Comparative Example 1: The soap film was manually generated. The operator manually timed 10 measurements using a high-precision stopwatch, recording the time interval between each passage of the soap film through the upper and lower scale lines.

[0100] Experimental indicators and data:

[0101] Average time interval (s): the average of 10 measurement times.

[0102] Standard deviation of time measurement (s): The standard deviation of 10 measurement times, reflecting the dispersion of the measured values.

[0103] Relative standard deviation of time measurement (RSD, %): the percentage of standard deviation to mean, reflecting measurement repeatability.

[0104] Table 2 Comparison of Time Measurement Accuracy

[0105]

[0106] As shown in Table 2, Example 2 of the present invention has significantly lower standard deviation and relative standard deviation in time measurement compared to Comparative Example 1. The automated photoelectric sensor timing in Example 2 eliminates the inherent reaction time and judgment errors of manual operation, resulting in more concentrated and consistent time interval data for each measurement, with a standard deviation of only 0.008 seconds and an RSD below 0.03%. This strongly demonstrates the beneficial effect of the present invention in "improving the accuracy of time measurement." Comparative Example 1, due to random errors introduced by manual operation and timing, suffers from a significant decrease in measurement repeatability, with an RSD as high as 0.498%, indicating lower reliability of its measurement results.

[0107] Comparative Experiment 3: Verification of the accuracy and adaptability of flow calculation; Experimental objective: To verify the accuracy of flow calculation under different environmental conditions and its adaptability to environmental changes of the present invention.

[0108] Experimental methods:

[0109] Referring to JJG632-2011 "Verification Procedure for Soap Film Flow Meters" and ISO6144:2005 standard, the standard conditions for gas flow rate are defined as 20°C and 101.325 kPa.

[0110] Design three sets of experimental environment conditions to simulate real-world applications:

[0111] Condition A (Standard approximate conditions): The ambient chamber is set to a temperature of 25°C, an atmospheric pressure of 101.3 kPa, and a relative humidity of 50%.

[0112] Condition B (High Temperature and High Humidity Conditions): The environmental chamber is set to a temperature of 35°C, an atmospheric pressure of 101.3 kPa, and a relative humidity of 80%.

[0113] Condition C (Low Pressure Conditions): The ambient chamber is set to a temperature of 25°C, an atmospheric pressure of 95.0 kPa, and a relative humidity of 50%.

[0114] For each experimental condition and two target flow rates (20 mL / min and 50 mL / min), the following procedures were performed:

[0115] The flow meters to be tested (Example 2, Comparative Example 1, and Comparative Example 2) were connected in series with a high-precision piston-type flow standard and placed in an environmental chamber. The piston-type flow standard stably outputs the target flow rate and records its displayed standard flow rate value (as the reference true value). Example 2: The device was started and five consecutive measurements were performed. The original volumetric flow rate (mL / min), gas temperature, gas pressure, gas moisture content detected by the system's built-in sensor, and standard flow rate (mL / min) calculated by the microcontroller were recorded for each measurement. The average standard flow rate of the five measurements was calculated and compared with the true standard flow rate output by the piston-type flow standard to calculate the relative error. Comparative Example 1: Five measurements were performed manually, and the original volumetric flow rate (mL / min) of each measurement was recorded. Since it cannot automatically perform state conversion, its original measured value can only be compared with the original flow rate value of the piston-type flow standard under the current environmental conditions to calculate the relative error of the original flow rate. Comparative Example 2: The device was started and five consecutive measurements were performed. The original volumetric flow rate (mL / min) and the standard flow rate (mL / min) corrected by its built-in temperature sensor were recorded for each measurement. Calculate the average standard flow rate and compare it with the true standard flow rate of the piston flow standard to calculate the relative error.

[0116] Experimental indicators and data:

[0117] Relative error of standard flow measurement (%): ((average measured standard flow - true standard flow of piston flow standard) / true standard flow of piston flow standard) * 100%. Relative error of raw flow measurement (%): ((average measured raw flow - true raw flow of piston flow standard) / true raw flow of piston flow standard) * 100%.

[0118] Table 3 Comparison of flow measurement errors under different operating conditions at a flow rate of 20 mL / min

[0119]

[0120] Table 4. Comparison of flow measurement errors under different operating conditions at a flow rate of 50 mL / min.

[0121]

[0122] As can be seen from Tables 3 and 4, under different flow rates (20 mL / min and 50 mL / min) and different environmental conditions (conditions A, B, and C), the relative error of the calculated standard flow rate in Example 2 of this invention remains within ±0.5%, demonstrating extremely high measurement accuracy and good adaptability to environmental changes. This is mainly due to the comprehensive environmental parameter data integrated by the temperature sensor, pressure sensor, humidity sensor, atmospheric pressure sensor, and ambient temperature sensor of this invention, as well as the comprehensive and accurate state conversion performed by the microcontroller based on this data. These data strongly demonstrate the beneficial effect of this invention in "improving the accuracy and adaptability of flow rate calculation".

[0123] Due to the inability to perform automatic state conversion, the deviation between the original measured value and the original value of the piston flow standard increases significantly when the environmental conditions deviate from the standard (especially under condition B of high temperature and high humidity and condition C of low pressure), resulting in an original flow measurement error as high as 2.0%, and it cannot provide accurate standard flow. This indicates that it has obvious defects in accuracy and adaptability.

[0124] While Comparative Example 2 possesses some automation functions and temperature-based correction, its standard flow measurement error is significantly higher than Example 2 (up to 1.5%) under high temperature and high humidity (condition B) and low pressure (condition C) conditions due to a lack of consideration for humidity and comprehensive pressure compensation (especially insufficient comprehensive consideration of inlet pressure and ambient atmospheric pressure). This directly demonstrates the crucial role of the multi-sensor integration and comprehensive condition conversion of this invention in "improving the accuracy and adaptability of flow calculation." This invention can effectively eliminate the influence of changes in ambient temperature, humidity, and pressure on flow measurement results, ensuring highly accurate standard flow data under various operating conditions.

[0125] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high efficiency gage diaphragm flowmeter for automatic continuous measurement, characterized by: The device is provided with a soap solution pool, a film forming device, a soap solution collecting cup and a single-chip microcomputer, wherein: The soap solution pool is provided with an air inlet; the soap film pipe is a vertical circular pipe installed above the soap solution surface, the upper part of the soap film pipe is communicated with the soap solution collecting cup; the soap film pipe is provided with upper and lower scale lines, and photoelectric sensors I and II are installed on both sides of the upper and lower scale lines; the photoelectric sensors I and II detect the time when the soap film passes and transmit signals to the single-chip microcomputer; the soap solution collecting cup is arranged on the air outlet of the soap film pipe and is used for collecting broken soap film liquid to prevent the broken soap solution from flowing back to the soap film pipe and affecting the normal work of the photoelectric sensor; The film forming device comprises a film forming frame, the film forming frame is installed between the soap film pipe and the soap solution pool, a tapered channel with open ends, wide bottom and narrow top is formed in the film forming frame, and the width of the tapered channel is greater than the diameter of the soap film pipe; the film forming frame is connected with a lifting mechanism, the film forming frame is driven to ascend and descend by the lifting mechanism, the soap film is generated in the tapered channel and is transferred into the soap film pipe; The lifting mechanism comprises a linear driver, a fixed plate and a push-pull rod; the film forming frame is connected to the push-pull rod, the push-pull rod is connected to the linear driver through the fixed plate, and the push-pull rod, the fixed plate and the film forming frame are driven to ascend and descend by the linear driver.

2. The continuously self-measuring high- efficiency soap-film flowmeter according to claim 1, characterized in that: The tapered channel is a circular conical channel or a prismatic channel.

3. The continuously self-measuring high efficiency soap film flowmeter of claim 1 wherein: The push-pull rod and the fixed plate are fixed by a hexagonal nut.

4. The continuously self-measuring high efficiency soap film flowmeter of claim 1 wherein: The soap solution collecting cup is provided with a plurality of connecting channels, and temperature sensors, pressure sensors and moisture content sensors connected to the single-chip microcomputer are arranged in the connecting channels.

5. The continuously self-measuring high efficiency soap film flowmeter of claim 1 wherein: The soap solution collecting cup is provided with an air outlet, and a drying bottle is connected to the air outlet of the soap solution collecting cup.

6. The continuously self-measuring high efficiency soap film flowmeter of claim 1 wherein: The single-chip microcomputer is connected to an atmospheric pressure sensor, an environmental temperature sensor, a display screen and a keyboard.

7. The method of using an automatically continuously measuring high- efficiency soap-film flowmeter according to any one of claims 1-6, characterized in that: The method comprises the following steps: S1, the single-chip microcomputer controls the linear driver to work, drives the push-pull rod to descend through the fixed plate, drives the film forming frame to descend and moves to the soap solution pool at the lower end of the soap film pipe; the bottom surface of the film forming frame is lowered below the soap solution surface of the soap solution pool; the soap solution pool is kept communicated with the gas source, and the gas continuously enters the soap solution pool above through the air inlet; S2, the linear driver drives the push-pull rod and the film forming frame to ascend, and a soap film is formed at the bottom of the film forming frame when the film forming frame is separated from the upper liquid surface of the soap solution; since the film forming frame is a tapered channel with open ends, wide bottom and narrow top, there is a pressure difference between the upper and lower surfaces of the soap film after the film forming frame is separated from the upper liquid surface of the soap solution, and the soap film moves from bottom to top under the action of the pressure difference; and the moving shape is an accelerated moving state, and the closer to the upper part of the tapered channel, the faster the moving speed; S3, in this process, the linear driver continues to drive the push-pull rod and the film forming frame to ascend, when the upper part of the tapered channel of the film forming frame passes through the bottom of the soap film pipe, the soap film in the tapered channel accelerates to move to the gas inlet of the soap film pipe under the action of the pressure difference, is smoothly pushed into the soap film pipe, and the soap film in the soap film pipe continues to ascend along the soap film pipe under the action of the flowing gas; until it moves to the upper end of the soap film pipe and enters the soap solution collecting cup; S4, when the soap film passes the photoelectric sensor I, the photoelectric sensor I transmits the detected signal to the single-chip microcomputer, and the timer of the single-chip microcomputer starts timing; when the soap film continues to move to the photoelectric sensor II, the photoelectric sensor II transmits the signal to the single-chip microcomputer, and the timing stops; S5, the single-chip microcomputer calculates the volume flow value of the gas flowing through the soap film flowmeter according to the movement time of the soap film between the photoelectric sensor I and the photoelectric sensor II and the volume value between the two scale lines of the soap film tube; the single-chip microcomputer displays the data measured by the temperature sensor, the pressure sensor and the humidity sensor, the atmospheric pressure sensor and the environmental temperature sensor, and converts the flow values in different states; the flow values under different temperature and pressure states are calculated; S6, the single-chip microcomputer, the linear driver and the photoelectric sensor are used to realize programmed automatic control of the number of times of measuring the flow value.

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