Multipurpose cloth air permeability testing equipment and testing method thereof

Abstract

The invention discloses multipurpose cloth air permeability testing equipment and a testing method thereof. The equipment adopts a lower-layer, middle-layer and upper-layer modular vertical stacking structure. The lower power module generates stable and adjustable vertical airflow. And the middle bearing module is used for clamping a sample and realizing leakage-free sealing. The upper visualization module comprises an uncovered liquid box with array holes, air flow penetrating through the cloth can be converted into a visible stable air column after liquid is injected, shaking of the cloth is restrained through hydrostatic pressure, and controllable back pressure is provided. The equipment can be integrated with an image analysis system and automatically extract gas column parameters. The testing method comprises the steps of precise sample loading and sealing, quantitative liquid injection, wind speed setting, gas-liquid coupling testing, multi-dimensional image analysis and multi-working-condition scanning. Visualization and stabilization of the ventilation process are achieved, the uniformity of cloth can be evaluated, the multi-wind-speed and multi-back-pressure environment can be simulated, dependence on a high-cost sensor is reduced, and the device and the method are suitable for research and development, quality control and teaching.

Description

Technical Field

[0001] This invention belongs to the field of fabric breathability testing technology, specifically relating to a multi-purpose fabric breathability performance testing device and its testing method. Background Technology

[0002] Fabric breathability is a key physical indicator determining its comfort, functionality, and suitability for specific applications (such as medical protection and outdoor sports). Currently, industry standard testing methods mainly rely on airflow measurement under a fixed pressure difference, and the corresponding equipment generally suffers from the following technical deficiencies:

[0003] 1. Traditional air permeability meters only output macroscopic average air permeability or air resistance. The testing process cannot provide crucial quality information such as airflow penetration path, uniformity of local pore distribution in the fabric, or the presence of microscopic blockages. For quality control of high-value-added or functional fabrics (such as uniformly moisture-wicking fabrics and symmetrically bonded fabrics), this lack of information is fatal.

[0004] 2. The core components are high-precision differential pressure sensors and flow meters, which leads to high equipment costs, complex calibration and maintenance, and sensitivity to environmental vibration and airflow pulsation, making it difficult to use stably in production sites or laboratories with limited resources.

[0005] 3. Operators cannot visually observe the physical process of airflow interacting with fabric while obtaining numerical results, which is not conducive to mechanism research and rapid problem diagnosis in teaching and R&D processes.

[0006] In the prior art, patent CN119322002A discloses a fabric breathability testing device, which adopts a T-tube structure and supplies air into a fixed tube through a fan, using the displacement of a porous sponge block to reflect the fabric's breathability. Although this device has a relatively simple structure, it still has the following shortcomings:

[0007] 1. Relying solely on distance sensors to indirectly measure airflow distribution makes it impossible to visualize the airflow penetration process and obtain crucial information such as fabric pore uniformity and localized blockages;

[0008] 2. During the test, the fabric is prone to shaking or bulging due to airflow impact, which affects the stability and repeatability of the test;

[0009] 3. Relying on a single wind speed and pressure condition makes it difficult to simulate the actual wearing environment with multiple wind speeds and back pressures;

[0010] 4. Lack of intelligent image analysis and data processing capabilities, test results rely on manual interpretation, resulting in low efficiency.

[0011] Therefore, there is an urgent market demand and technological value in developing a fabric breathability testing device that can intuitively visualize the breathability process, flexibly simulate multiple wind speed conditions, combine qualitative evaluation and quantitative analysis capabilities, and has a relatively simple and reliable structure. Summary of the Invention

[0012] This invention provides a multi-purpose fabric breathability testing device and method. By forming a stable air column through gas-liquid coupling, the invisible airflow penetration process is transformed into a clearly visible image. Combined with intelligent image analysis, it can not only indirectly obtain breathability performance indicators, but also evaluate the airflow state and fabric uniformity through parameters such as the height, diameter, and stability of the air column. This overcomes the limitations of traditional "black box testing" and solves the problems mentioned in the background art.

[0013] To achieve the above objectives, the present invention provides the following technical solution: a multi-purpose fabric breathability testing device, wherein the device adopts an integrated design of three-layer modular vertical stacking, with each module having a clear function and working together to achieve accurate testing.

[0014] 1. Lower power and current stabilization module

[0015] The core of this module is to generate a stable, vertical, and adjustable-speed uniform airflow, including:

[0016] The rigid housing has an air inlet, the position of which can be set as needed. The interior forms a primary pressure stabilization space, which effectively buffers the airflow pulsation generated by the fan and provides a pressure equalization environment for the upstream airflow.

[0017] The DC brushless fan, housed in a rigid enclosure, is equipped with a PID speed controller and a wind speed feedback sensor to achieve precise, stable, and continuously adjustable outlet airflow. The enclosure panel features a touchscreen for setting, displaying, and recording the wind speed. A deep-layer honeycomb aluminum rectifier or a combination of a honeycomb rectifier and multi-layer stainless steel wire mesh is fixedly installed directly above the fan outlet and below the downdraft. This design minimizes turbulence and rotational components, transforming the airflow into a highly developed, uniformly distributed, and time-stable vertical jet, ensuring excellent uniformity and temporal stability of the airflow directed at the fabric.

[0018] Downflow vent and primary airflow guide seal: A circular downflow vent is located on the top plate of the enclosure, which achieves a static seal with the lower end of a transparent, high-strength acrylic circular tube (i.e., the air duct). The air duct serves as a vertical airflow guiding channel, and its transparency provides a process monitoring window.

[0019] 2. Central fabric support and multiple dynamic sealing modules

[0020] This module is key to achieving accurate testing, responsible for clamping the sample and constructing a leak-free test area.

[0021] Rigid Frame and Reference Plane: Transparent baffles extending vertically upwards from the four sides of the top plate of the housing connect with the high-flatness cover plate at the top, forming a rigid intermediate housing frame. The cover plate serves as the load-bearing reference surface for the fabric, requiring a flatness error of less than 0.05mm.

[0022] Upper air vent and secondary guide seal: The cover plate has an upper air vent that is strictly coaxial with the lower air vent. The innovative design features an integrally formed annular boss along the edge of the upper air vent, with a height of 1-3mm and a precision-ground top surface. The upper end of the air duct is tightly fitted onto the outside of the boss via another set of sealing rings, forming a labyrinth seal. This structure not only achieves a seal but also ensures that the airflow outlet direction is strictly perpendicular to the cover plate plane.

[0023] Fabric edge sealing system: An annular sealing groove with a trapezoidal or rectangular cross-section is machined on the upper surface of the cover plate, surrounding the outer perimeter of the boss. A highly elastic silicone or fluororubber sealing strip with a low compression set is embedded within the groove. Correspondingly, the lower surface of the upper housing base plate, in the area contacting the sealing strip, can be designed as a slightly convex annular surface or have a flexible gasket attached. When liquid is applied downwards from the top, the sealing strip is three-dimensionally compressed: not only is it vertically pressed, but its soft material also flows laterally, tightly filling the microscopic gaps and surface unevenness created by the interwoven fabric fibers. This filling-type seal effectively adapts to fabrics of different thicknesses and surface textures (such as terry cloth and napped fabric), physically eliminating the "short-circuit" phenomenon of airflow leakage from the sample edge, ensuring that all measured airflow is forced through the effective test area of ​​the fabric.

[0024] 3. Upper visualization, support, and quantitative analysis module

[0025] This module transforms airflow signals into a visible, measurable, and analyzable form and introduces a key stabilization mechanism.

[0026] Open-top observation tank: This is an open-top box with a bottom and sides made of transparent sheet material (such as polycarbonate). Its bottom plate, facing the updraft, has multiple arrayed holes. The outlet ends of the arrayed holes are immersed in the liquid inside the tank, while the inlet ends are connected to the bottom plate of the upper chamber via a sealing structure to ensure airtightness. The inner diameter and number of arrayed holes can be selected and changed according to testing requirements and expected airflow rate. Preferably, considering the stability of the connection between the upper and middle modules, side limiting devices can be conventionally set, such as positioning protrusions on the middle module cover and corresponding positioning grooves on the upper module for limiting. Conventional techniques are not described in the accompanying drawings.

[0027] Gas-liquid coupling and dynamic stabilization mechanism: During testing, a certain height of transparent liquid (such as deionized water) is injected into the upper chamber. This design produces multiple synergistic effects:

[0028] Visualization medium: Airflow penetrating the fabric enters the liquid through arrayed holes, forming a continuous and stable air column (i.e., a clearly visible airflow channel), making the invisible flow process fully visible. By observing the shape, height, diameter, and stability of the air column, the airflow state can be directly assessed.

[0029] Applying a stable holding force: The gravity of the liquid is evenly transferred to the clamped fabric through the bottom plate of the upper chamber. This downward hydrostatic pressure and the upward aerodynamic pressure generated by the fan form a dynamic balance on the fabric plane. This balanced force field effectively "irons" the fabric and keeps it firmly against the cover plate reference surface, significantly reducing fabric shaking, fluttering, or local bulging that may be caused by airflow impact, greatly improving the stability of the test state, thereby obtaining clearer and more reliable air column images and test data.

[0030] Enhanced sealing effectiveness: The additional pressure from the liquid gravity further strengthens the contact pressure between the fabric and the lower sealing ring, improving the reliability of the edge seal.

[0031] It provides a controllable back pressure environment: the liquid column height (h) generates a static back pressure of approximately ρgh. By adjusting the liquid level, the net pressure difference acting on the fabric can be fine-tuned, providing another adjustable parameter for simulating the microenvironment pressure under different wearing conditions.

[0032] Comprehensive protection against liquid backflow: Safety is ensured through a triple mechanism: ① Positive gas pressure barrier: During fan operation, the duct maintains a positive pressure higher than the static pressure of the liquid column. ② Arrayed hole structure design: Utilizing liquid surface tension and continuous airflow pressure, liquid backflow or entry into the duct is effectively prevented. ③ Mechanical seal barrier: The aforementioned adaptive sealing system fundamentally blocks the path of liquid seeping laterally into the duct along the fabric edge.

[0033] Integrated Intelligent Image Analysis System: The equipment comes standard with or can be equipped with a system consisting of a high frame rate CMOS camera, a coaxial LED cold light source, and dedicated analysis software. The camera captures images of the gas column from the side or obliquely above the liquid tank. The software features real-time image processing algorithms that can automatically identify the boundaries of the gas column within the liquid column and analyze and calculate key parameters such as the average height, average diameter, height fluctuation variance, and morphological stability index of the gas column.

[0034] A test method for the air permeability of multi-purpose fabrics

[0035] Based on the above equipment, the testing method is as follows, with each step closely corresponding to and utilizing the specific structural design of the equipment:

[0036] Step S1: Precision sample loading and active seal establishment

[0037] Clean the reference surface of the cover plate and the sealing strip. Flatten the sample and cover the upper air vent and sealing groove area. Precisely lower the upper box using the positioning guide posts.

[0038] Step S2: Quantitative liquid injection and test environment setup

[0039] Inject a transparent liquid to a predetermined height H using a metering pump or graduated container. Before injection, start the fan at the minimum recommended wind speed to prevent backflow and seepage. Record the value of H, which, along with the liquid density ρ, determines the static pressure ρgH applied to the fabric. Ensure consistent sealing conditions for each test using a pressure sensor or torque calibration. Set the test wind speed V_set on the controller. The system starts the fan and automatically adjusts to V_set, waiting for the wind speed sensor feedback value to stabilize within the set tolerance range (e.g., ±2%).

[0040] Step S3: Gas-Liquid Coupling Test Operation and Process Monitoring

[0041] A stable airflow impacts the fabric vertically. At this point, the fabric is in a state of mechanical equilibrium, influenced by the upward aerodynamic pressure P_air and the downward hydrostatic pressure P_liquid. This state greatly suppresses any unstable movement of the fabric. After penetrating the fabric, the airflow enters the liquid through the array holes, forming a clearly visible air column. The operator can directly observe the shape of the air column from the side, and the camera simultaneously records video for subsequent analysis.

[0042] Step S4: Multi-dimensional information extraction and analysis

[0043] Qualitative analysis: Visually assess the overall stability of the air column, its continuity, and whether there are any violent swings, breaks, or irregular shapes. Quickly determine if the fabric has large holes or severely blocked areas.

[0044] Quantitative analysis:

[0045] The software analyzes consecutive video frames, uses image processing algorithms (such as edge detection and threshold segmentation) to identify the outline of the air column, and calculates its core parameters.

[0046] Average height of air column (H_air): reflects the ability of airflow to penetrate liquid under a given pressure difference, and is positively correlated with air permeability.

[0047] Average diameter of the air column (D_air): related to airflow rate and effective breathable area of ​​the fabric.

[0048] Air column stability index (S_air): obtained by calculating the variance or standard deviation of the air column height or diameter over time, reflecting whether the airflow is stable and whether the fabric structure is uniform.

[0049] Meanwhile, the state of the airflow after passing through the fabric can be indirectly assessed by analyzing the clarity or turbulence of the air column edge.

[0050] A quantitative relationship model was established: using a set of standard samples with known permeability (measured according to standard methods), tests were conducted under different combinations of wind speed V_set and liquid level H to obtain multiple sets of data (V_set, H, H_air, D_air, S_air). Through multiple regression analysis, a predictive model was established from easily measurable image parameters (H_air, D_air, etc.) to engineering parameters (standard permeability, uniformity level), achieving a standardized interpretation of the results of this method.

[0051] Step S5: Multi-condition scanning and performance graph plotting

[0052] With a fixed liquid level H, gradually change the wind speed V_set (e.g., from 0.5, 1, 2, 5, 10 m / s) and repeat the test. The fabric's "air column height-wind speed response curve" (H_air ~ V_set) and "air column diameter-wind speed response curve" (D_air ~ V_set) can be plotted to visually demonstrate its permeability behavior under different wind pressures, determining whether it exhibits a "linear response" or a "threshold-activated" response (e.g., windproof and breathable membranes). Alternatively, with a fixed wind speed and varying liquid level H, the influence of back pressure on the air column morphology parameters can be studied.

[0053] Step S6: Secure Termination and Data Archiving

[0054] Smoothly shut down the blower. After the air column disappears, release the clamping mechanism and remove the sample. The system software automatically generates a test report containing test conditions, process images, key parameters, and analytical conclusions.

[0055] Compared with the prior art, the beneficial effects of the present invention are:

[0056] 1. By forming a stable air column through gas-liquid coupling, the invisible airflow penetration process is transformed into a clearly visible image. Combined with intelligent image analysis, it can not only indirectly obtain air permeability performance indicators, but also evaluate the airflow state and fabric uniformity through parameters such as the height, diameter, and stability of the air column, breaking through the limitations of the traditional "black box test".

[0057] 2. By dynamically balancing the hydrostatic pressure and pneumatic pressure, the shaking and bulging of the fabric under the impact of airflow are effectively suppressed; the sealing system ensures that there is no leakage in the test area, providing a stable mechanical environment for high-precision testing.

[0058] 3. The wind speed is continuously adjustable and the liquid level (back pressure) is controllable. It can easily simulate the breathability behavior under different micro-environment pressures, from calm wind to strong wind. It is suitable for dynamic performance evaluation in various application scenarios such as sportswear, protective clothing, and tent fabrics.

[0059] 4. The core detection mechanism is based on optical image analysis of a stable air column, reducing reliance on high-precision, high-cost differential pressure sensors and flow meters. Its modular design facilitates maintenance, is insensitive to vibrations and electromagnetic interference in the production environment, and has wider applicability.

[0060] 5. It has the ability to automatically recognize images, extract parameters, model and generate reports, which greatly improves the testing efficiency and the scientific nature of the results interpretation. It supports the application of fabric research and development, quality control and teaching throughout the entire process, and realizes the leap from "measurement" to "analysis and diagnosis". Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the testing equipment of the present invention.

[0062] Figure 2 for Figure 1 A schematic diagram of the longitudinal cross-section structure.

[0063] Figure 3 for Figure 2 A magnified structural diagram of region A in the middle.

[0064] Figure 4 This is a top view schematic diagram of the annular sealing groove and sealing strip.

[0065] Figure 5 This is a top view of the upper module.

[0066] Figure 6 This is a schematic diagram of the testing method flow.

[0067] In the diagram: 1. Housing; 2. Fan; 3. Downward air outlet; 4. Rectifier; 5. Air duct; 6. Cover plate; 7. Upward air outlet; 8. Annular boss; 9. Annular sealing groove; 10. Sealing strip; 11. Upper housing bottom plate; 12. Flexible gasket; 13. Uncovered liquid tank; 14. Array holes; 15. Liquid. Detailed Implementation

[0068] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] Example 1: Specific Structure of the Equipment

[0070] Please see Figures 1 to 5This embodiment provides a multi-purpose fabric breathability performance testing device, which adopts a three-layer modular vertical stacking design (lower, middle and upper layers). Each module has a clear function and works together to achieve visualization, stabilization and intelligent analysis of the fabric breathability process.

[0071] Lower power and current stabilization module

[0072] The core function of this module is to generate a stable, vertical, and continuously adjustable uniform airflow, providing a reliable aerodynamic input for testing.

[0073] Rigid housing 1 and primary pressure stabilization: Housing 1 adopts a welded metal structure, forming a pressure stabilizing chamber with a certain volume inside. The airflow generated by fan 2 is initially buffered and pressure equalized within this chamber, effectively reducing airflow pulsation.

[0074] Adjustable wind speed system: A DC brushless fan 2 is used in conjunction with a PID speed controller and a wind speed sensor to form a closed-loop control system. Preferably, a touch screen is installed on the front panel of the housing 1. The operator can set the target wind speed through the touch screen, and the system automatically adjusts the speed of the fan 2 to quickly stabilize the actual wind speed near the set value (e.g., ±2%), achieving precise and continuous adjustment of the wind speed.

[0075] Airflow rectification and guidance: A deep honeycomb aluminum rectifier 4 (or combined with multi-layer wire mesh) is installed between the outlet of fan 2 and the downdraft outlet 3. This rectifier 4 effectively breaks up turbulent vortices, eliminates the rotational component of the airflow, and transforms the airflow into a highly uniform and stable vertical jet. The transparent air guide duct 5 not only guides the airflow vertically upward but also provides a window for observing the airflow status. The lower end of the air guide duct 5 and the edge of the downdraft outlet 3 on the top plate of the housing 1 achieve a primary static seal through adhesive or a sealing ring to prevent airflow leakage.

[0076] Central fabric support and multiple dynamic sealing modules

[0077] This module is the core of ensuring test accuracy and repeatability. It is responsible for the precise positioning and clamping of the sample and for creating a leak-free test area.

[0078] High-precision reference plane: The cover plate 6 serves as the fabric bearing surface, and its flatness is ensured by precision machining, providing a stable support reference for the fabric.

[0079] Coaxial airflow outlet and secondary seal: The cover plate 6 is machined with an upper air outlet 7 that is strictly coaxial with the lower air outlet 3, and the edge is provided with an integrally formed annular boss 8. The upper end of the air guide duct 5 is fitted onto the outside of the annular boss 8 through a fluororubber sealing ring, forming a labyrinth-type secondary seal. This structure ensures that the airflow outlet direction is strictly perpendicular to the plane of the cover plate 6 and geometrically limits the lateral leakage path.

[0080] Edge sealing system: An annular sealing groove 9 is formed around the annular boss 8 on the upper surface of the cover plate 6, and a highly elastic sealing strip 10 (such as silicone) with a low compression set is embedded in the groove. A flexible gasket 12 is provided on the lower surface of the corresponding upper housing bottom plate 11. When the upper module is pressed down, the sealing strip 10 is subjected to three-dimensional compression: it is compacted in the vertical direction, while its soft material flows laterally, filling the microscopic gaps formed on the fabric surface due to fiber interweaving and texture undulations (such as loops and napped surfaces). This design can intelligently adapt to fabrics of different thicknesses and surface conditions, fundamentally eliminating the "short-circuit" phenomenon of airflow leakage from the edge of the sample, and ensuring that all metering airflow is forced through the effective test area of ​​the fabric.

[0081] Upper visualization, support and quantitative analysis module

[0082] This module transforms the invisible airflow penetrating the fabric into a visible, measurable, and analyzable image signal, and introduces a key mechanical stabilization mechanism.

[0083] Gas-liquid coupling and visualization: The bottom plate of the uncovered liquid tank 13 is provided with array holes 14. Multiple array holes 14 are preferably arranged in an array, with the specific number determined according to requirements, corresponding to the area above the updraft vent 7. During testing, a certain height of transparent liquid 15 (such as deionized water) is injected into the uncovered liquid tank 13. The airflow penetrating the fabric enters the liquid 15 through the array holes 14, forming a continuous and stable visible air column, thus fully visualizing the penetration state and intensity distribution of the airflow.

[0084] Dynamic stabilizing pressure holding mechanism: The gravity of liquid 15 generates a uniform hydrostatic pressure (ρgH) acting on the fabric. This pressure forms a dynamic balance with the upward aerodynamic pressure generated by the fan 2 below on the fabric plane. This balanced force field effectively suppresses the shaking, fluttering, or bulging of the fabric caused by the airflow impact, "ironing" the fabric and keeping it tightly attached to the reference surface of the cover plate 6, greatly improving the stability of the test state and laying the foundation for obtaining clear and reliable air column images.

[0085] Controllable back pressure environment: By adjusting the liquid level height (H), the static back pressure acting on the fabric can be changed, providing adjustable parameters for simulating different micro-environment pressure conditions (such as the local pressure when wearing clothing).

[0086] Integrated Intelligent Image Analysis System: The system is equipped with a high-frame-rate CMOS camera, a uniform illumination source, and dedicated analysis software. The camera captures images of the gas column from the outside of the transparent sidewall of the liquid tank. The software employs image processing and analysis algorithms (such as Canny edge detection and Otsu thresholding) and parameter extraction logic (such as formulas for calculating gas column height and diameter). Conventional techniques will not be described in detail. It can automatically identify the gas column outline in real time and output multi-dimensional quantitative indicators, including:

[0087] Average height of the air column (H_air): The average vertical distance from the outlet of the array aperture to the top of the air column.

[0088] Average diameter of the air column (D_air): The average diameter of the main body of the air column.

[0089] Air column stability index (S_air): Calculated by the variance or standard deviation of the air column height or diameter over time. It reflects whether the airflow is stable and whether the fabric structure is uniform. The smaller the value, the more stable it is.

[0090] Example 2: Specific steps of the testing method and the linkage of equipment functions

[0091] Please see Figure 6 Based on the device in Example 1, the testing method flow is as follows, with each step closely corresponding to and making full use of the specific design of the device:

[0092] S1: Precision sample preparation and sealing establishment

[0093] Clean the reference surface of the cover plate 6 and the sealing strip 10. Flatten the fabric sample and cover the upper air vent 7 and the sealing groove area. Lower the upper module along the positioning guide post, the sealing system is activated, the sealing strip 10 deforms and fills the microscopic gaps at the edge of the fabric, forming a reliable seal.

[0094] S2: Quantitative Injection and Test Environment Setup

[0095] A transparent liquid is injected to a preset height H using a metering pump, and the static back pressure ρgH is recorded. Before injection, the minimum wind speed is selected to start the fan to prevent backflow and seepage. The test wind speed V_set is set on the touchscreen. The system starts fan 2, and PID closed-loop control ensures it quickly reaches and stabilizes at V_set.

[0096] S3: Gas-Liquid Coupling Test Operation and Process Monitoring

[0097] A stable airflow impacts the fabric vertically. The fabric remains highly stable under the dynamic balance of upward aerodynamic force, downward hydrostatic pressure from the liquid 15, and clamping force. After penetrating the fabric, the airflow enters the liquid 15 through the array holes 14, forming a stable air column. The operator can visually observe the shape of the air column from the side in real time, while a camera simultaneously records video.

[0098] S4: Multi-dimensional Information Extraction and Analysis

[0099] Qualitative assessment: Directly observe whether the air column is continuous and stable, and whether there is violent shaking or interruption, to quickly screen whether the fabric has obvious uneven air permeability or defects.

[0100] Quantitative analysis: The analysis software automatically processes the recorded video, extracts the air column contour in each frame of the image through image recognition algorithms, and calculates and outputs core parameters such as H_air, D_air, and S_air.

[0101] Model-based interpretation: By using a multivariate regression model (such as multivariate linear regression or neural network) established in advance using standard samples, the measured (V_set, H, H_air, D_air, S_air) data are transformed into parameters familiar to engineering, such as the equivalent air permeability (mm / s) and air permeability uniformity level under standard pressure difference.

[0102] S5: Multi-condition scanning and performance graph plotting

[0103] Variable wind speed scanning: With the liquid level H fixed, the wind speed V_set is gradually changed to plot the "air column height-wind speed response curve" and "air column diameter-wind speed response curve" of the fabric. The variation of its air permeability with wind pressure is analyzed to determine the fabric type.

[0104] Variable back pressure scanning: With a fixed air velocity and varying liquid level H, the influence of back pressure (microenvironmental pressure) on air column morphology parameters is studied to evaluate the breathability of the fabric under different pressures.

[0105] S6: Secure Termination and Data Archiving

[0106] Smoothly shut down fan 2. After the air column has completely disappeared, release the clamping mechanism and remove the sample. The system automatically generates a structured test report, including all test conditions, key images, quantitative results, and analytical conclusions, achieving traceability of the testing process and standardized management of data.

[0107] Through the detailed elaboration of the above specific embodiments, the core advantages of the device of the present invention are clearly demonstrated: based on gas-liquid coupling visualization, with dynamic mechanical balance and adaptive sealing as guarantees, and with intelligent image analysis as a means, a comprehensive, stable, reliable and information-rich fabric air permeability test platform is constructed, realizing the leap from single air permeability measurement to multi-dimensional performance analysis and diagnosis.

[0108] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, all of which are within the scope of protection of the present invention.

Claims

1. A multi-purpose fabric air permeability testing device, characterized in that, It includes an upper module, a middle module, and a lower module that are arranged sequentially from top to bottom and can be detachably connected; The lower module includes a housing (1), a fan (2) installed inside the housing (1), and a rectifier (4) located above the air outlet of the fan (2). The top of the housing (1) is provided with a downdraft (3). The middle module includes a cover plate (6), on which an upper air outlet (7) coaxial with the lower air outlet (3) is provided, and an annular sealing groove (9) is provided around the upper air outlet (7) on the upper surface of the cover plate (6). The upper module includes an open liquid tank (13), and the bottom plate of the open liquid tank (13) is provided with multiple array holes (14) in the area facing the upper air vent (7). During testing, the open liquid tank (13) is filled with transparent liquid (15); a test area for clamping the fabric sample is formed between the cover plate (6) and the bottom plate of the open liquid tank (13).

2. The multi-purpose fabric air permeability testing equipment according to claim 1, characterized in that, The cover plate (6) has an integrally formed annular boss (8) on the edge of the upper air outlet (7) for positioning and stabilizing the air duct; it also includes a transparent air duct (5), the lower end of which is sealed to the lower air outlet (3), and the upper end is sleeved on the outside of the annular boss (8) to form a seal.

3. The multi-purpose fabric air permeability testing equipment according to claim 2, characterized in that, The lower end of the air duct (5) is statically sealed to the downdraft (3) by adhesive bonding; and / or, a sealing ring is provided between the air duct (5) and the annular boss (8).

4. The multi-purpose fabric air permeability testing equipment according to claim 1, characterized in that, The annular sealing groove (9) is embedded with a sealing strip (10), and a flexible gasket (12) is provided on the lower surface of the bottom plate of the uncovered liquid tank (13) in the contact area corresponding to the sealing strip (10). The sealing strip (10) and the flexible gasket (12) together constitute an edge sealing system for adapting to different fabric surface textures.

5. The multi-purpose fabric air permeability testing equipment according to claim 1, characterized in that, The rectifier (4) is a deep honeycomb aluminum rectifier or a combination of honeycomb and multi-layer stainless steel wire mesh, used to convert airflow into a vertical uniform jet.

6. The multi-purpose fabric air permeability testing equipment according to claim 1, characterized in that, It also includes a wind speed control system, which includes a PID speed controller, a wind speed sensor and a human-machine interface, used to achieve precise, continuous, adjustable and stable outlet wind speed.

7. The multi-purpose fabric breathability testing equipment according to claim 1, characterized in that, It also includes an image analysis system, which includes a camera, a light source and analysis software, for capturing images of the gas column formed inside the uncovered liquid tank (13) and automatically analyzing and calculating at least one of the following parameters: the average height, the average diameter and the stability index of the gas column.

8. A testing method based on the multi-purpose fabric breathability testing equipment according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Sample loading and sealing: The fabric sample is flattened and covered on the upper air vent (7) and the annular sealing groove (9) area of ​​the cover plate (6), and then the upper module is pressed down to clamp the sample and form an edge seal. S2: Liquid injection and setting: Inject a predetermined amount of transparent liquid (15) into the uncovered liquid tank (13) and set the test wind speed; S3: Test run: Start the fan (2), adjust to the set wind speed, stabilize the airflow and vertically penetrate the fabric sample into the liquid (15) to form a visible air column; S4: Information extraction: Obtain the morphological information of the air column through direct observation and / or image analysis system; S5: Analysis and Evaluation: Based on the morphological information, perform a qualitative evaluation and / or quantitative analysis of the fabric's breathability.

9. The test method according to claim 8, characterized in that, In step S5, the quantitative analysis includes: fixing the liquid level height, gradually changing the test wind speed, and plotting the response curve of the air column morphology parameters as a function of wind speed; and / or, fixing the test wind speed, gradually changing the liquid level height, and studying the influence of back pressure on the air column morphology parameters.

10. The test method according to claim 8, characterized in that, In step S2, before injecting the transparent liquid (15), the fan (2) is started and run at the lowest wind speed to establish a positive pressure barrier in the air duct to prevent the liquid from being drawn back into the lower air duct through the array hole (14) during injection or in the early stage of testing.

Images