A device for detecting the air permeability of cashmere fabric

Abstract

The application discloses a cashmere fabric air permeability detection device and relates to the technical field of fabric air permeability detection.The device comprises a rack and an airflow nozzle piece and further comprises a second component for switching the airflow nozzle piece.The second component comprises a first auxiliary pipe fixedly connected to the rack, and an inlaid groove A is formed in the annular bottom surface of the first auxiliary pipe.The design of the second component brings many benefits to the problems of complicated operation, damage to the health of the operator and low test efficiency caused by manual replacement of the nozzle piece in the prior art, and is different from the complicated process of manually disassembling, installing and calibrating the nozzle piece in the prior art.The component automatically switches the nozzle pieces with different apertures through automatic control, and manual operation in the internal rack cabinet is not needed.The operation process does not need tools and repeated position adjustment, greatly simplifying the operation process, and even novice operators can quickly master the use method, effectively reducing the operation difficulty.

Description

Technical Field

[0001] This invention relates to the field of fabric air permeability testing technology, specifically to a device for testing the air permeability of cashmere fabrics. Background Technology

[0002] Fabric air permeability testers are key equipment in the textile industry used to determine the air permeability of various fabrics (such as cashmere, cotton, and synthetic fiber fabrics). They simulate the interaction between fabric and air in a real-world environment, measuring the amount of air passing through a unit area of ​​fabric per unit time, thereby evaluating the fabric's wearing comfort, functional suitability, and product quality. The general procedure is as follows: First, representative fabric samples are selected, conditioned to a standard environment, and fixed on the test platform. Then, the equipment is started to create a stable pressure difference across the sample, and the air permeability is calculated by measuring the gas flow rate. Finally, the air permeability of the fabric is comprehensively evaluated based on the test results of multiple samples.

[0003] In existing technologies, the nozzle replacement process of fabric air permeability testers has significant drawbacks. Different fabrics with varying air permeability require nozzles with different orifice diameters; for example, high-permeability fabrics require large-orifice nozzles, while low-permeability fabrics require small-orifice nozzles. For samples with unknown air permeability, operators must conduct pre-tests by repeatedly replacing nozzles to determine the appropriate nozzle specifications. However, nozzle replacement in existing equipment largely relies on manual operation: nozzles are typically installed in a confined space inside the machine cabinet and must be secured by screwing or clipping. During replacement, operators must repeatedly bend over, reach into the cabinet to remove the old nozzle, install the new nozzle, and calibrate its position. This process is not only cumbersome and time-consuming but also poses a significant health risk due to the prolonged bending and lowering of the head, easily leading to cervical and lumbar spine strain.

[0004] Furthermore, existing fabric air permeability testers generally employ a straight-cylinder structure for their gas pipes, a design with significant airflow control deficiencies. Airflow within a straight-cylinder pipe is prone to turbulence due to several factors: first, the pulsating airflow from the air source (such as a suction fan) directly enters the pipe, creating periodic velocity fluctuations; second, when airflow enters the pipe from an open space, abrupt changes in cross-section cause boundary layer separation, forming vortices on the pipe's inner wall; and third, roughness of the pipe's inner wall or minute protrusions at connection points can disturb the airflow, inducing localized turbulence. These factors result in uneven airflow distribution through the nozzle, manifesting as significant differences in airflow velocity across different areas of the sample surface; for example, a higher velocity at the center and a lower velocity at the edges, leading to errors in pressure difference and gas flow rate measurement, ultimately affecting the accuracy of air permeability calculations. Simultaneously, turbulent airflow also leads to poor test data stability, making it difficult to meet high-precision testing requirements and adversely impacting the scientific validity of fabric quality evaluation.

[0005] In summary, existing fabric air permeability testers have significant shortcomings in terms of the ease of nozzle replacement and the stability of airflow in the gas pipeline. These shortcomings urgently need to be addressed through structural optimization and automation upgrades to improve the equipment's operational comfort, testing efficiency, and data reliability.

[0006] Therefore, this invention proposes a device for testing the air permeability of cashmere fabrics to solve the above problems. Summary of the Invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide a cashmere fabric air permeability testing device to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a cashmere fabric air permeability testing device, comprising: a frame and an airflow nozzle plate, and further comprising: a second component for switching the airflow nozzle plate;

[0009] The second component includes a first auxiliary tube fixedly connected to the frame, and an embedded groove A is provided on the annular bottom surface of the first auxiliary tube. An embedded groove B is provided on the same vertical line as the embedded groove A.

[0010] A servo motor is fixedly connected to the top wall of the inner cavity of the frame. An adjustment plate is fixedly connected to the drive shaft end of the servo motor. Grooves are equidistantly arranged around the adjustment plate. Pneumatic devices are fixedly connected to each groove of the adjustment plate. A connecting pipe is fixedly connected to the pneumatic device.

[0011] The adjustment disc is equidistantly fitted and fixed with a support ring body, and a movable ring is symmetrically slidably connected to the support ring body. A sealing gasket is fixedly connected to the outer end face of the movable ring, and the plane where the connecting pipe is located coincides with the middle plane of the support ring body.

[0012] The airflow nozzles are all fixedly connected to the inner ring wall of the moving ring. The orifice size of the airflow nozzles, which are equidistantly distributed on the same plane of the adjustment disc, gradually increases clockwise. Strain gauges are fixedly connected to the outer end face of the sealing gasket.

[0013] As an improvement, a first component fixed to the rack is also included;

[0014] The first component includes a support piece fixedly connected to the upper surface of the frame, an auxiliary piece placed in the inner annular groove of the support piece, and a fastening cover fastened to the outer periphery of the support piece;

[0015] An electric pressure rod is provided on the frame. An auxiliary ring is fixedly connected to the outer end of the electric pressure rod. Springs are fixedly connected at equal intervals to the bottom surface of the auxiliary ring. A pressure head is fixedly connected to the bottom surface of the springs. The top end of the pressure head slides against the inner wall of the auxiliary ring.

[0016] The bottom surface of the auxiliary ring is provided with column grooves at equal intervals, and the bottom ring surface of the pressure head is fixedly connected with guide rods at equal intervals. The guide rods are sleeved by springs, and their top ends slide within the column grooves on the bottom surface of the auxiliary ring.

[0017] As an improvement, a third component located within the rack cavity is also included;

[0018] The third component includes a support frame fixedly connected to the inner cavity of the frame, a second auxiliary tube fixedly connected to the support frame, and an involute tube fixedly connected to the upper end of the second auxiliary tube;

[0019] The top of the involute is fixedly connected to the tapered tube via a flange, and the inner groove B is formed on the top of the tapered tube.

[0020] As an improvement, a spiral guide vane is fixedly connected inside the converging tube, radial guide vanes are fixedly connected at equal intervals on the inner wall of the involute tube, and a differential pressure sensor is fixedly connected to the inner wall of the second auxiliary tube.

[0021] As an improvement, a sealing sheet is fixed to the bottom surface of the pressure head.

[0022] As an improvement, the pneumatic device is a small screw pump.

[0023] As an improvement, the involute tube has an inner diameter that gradually increases from top to bottom, while the converging tube has an inner diameter that gradually decreases from top to bottom.

[0024] Compared with the prior art, the present invention provides a device for testing the air permeability of cashmere fabrics, which has the following beneficial effects:

[0025] 1. Through the design of the second component, this invention addresses the problems of cumbersome operation, long time consumption, harm to operator health, and low testing efficiency associated with manual nozzle replacement in the prior art, bringing significant benefits in many aspects:

[0026] Significantly improves ease of operation: Unlike the tedious process of manually disassembling, installing, and calibrating nozzles one by one in existing technologies, this component achieves automatic switching of nozzles with different orifice diameters through automated control, eliminating the need for manual operation by reaching into the rack cabinet. This process does not require tools or repeated adjustments, greatly simplifying the operation process. Even novice operators can quickly master the usage method, effectively reducing the difficulty of operation.

[0027] Significantly improves testing efficiency: In existing technologies, manual replacement of nozzle plates for pre-testing of samples with unknown air permeability often requires multiple repetitions, with each replacement taking a long time and affecting the testing progress. However, the automatic switching function of the second component can complete the replacement and calibration of nozzle plates in a short time, greatly shortening the time of the pre-testing stage. At the same time, when testing fabrics with different air permeability in batches, there is no need to frequently interrupt the test for manual replacement, which can realize a continuous and efficient testing process, significantly improving the overall testing efficiency. It is suitable for scenarios with high testing requirements, such as factories and laboratories.

[0028] Ensuring operator health: In existing technologies, operators need to repeatedly bend over and reach into the cabinet to change nozzles. Maintaining this poor posture for a long time can easily lead to cervical and lumbar strain. The design of the second component completely changes this operating method. Operators no longer need to enter confined spaces or maintain a bent-over posture. They can simply switch nozzles through the operating interface, fundamentally avoiding the potential threats to their health caused by improper operating posture. This reflects humanistic care for operators and helps improve work comfort and occupational health.

[0029] 2. This invention, by using a second component where the gas-driven nozzle plate is located in a moving ring connected to the first auxiliary pipe and the tapered pipe, further expands the functional reliability of the equipment through the coordinated design of air pressure sensing and quantitative air supply, based on the automatic nozzle plate switching, and brings the following significant beneficial effects:

[0030] Real-time and accurate monitoring of nozzle installation status avoids human error: Compared to traditional manual replacement methods that rely on visual or tactile judgment to determine installation accuracy, this design achieves "non-contact accurate detection" through a pressure sensor within the support ring. When the movable ring containing the nozzle smoothly enters the inner groove and completes docking, the support ring and movable ring form a sealed space. The metered gas injected by the pneumatic device remains at low pressure due to the absence of leakage, resulting in a low pressure sensor reading and providing direct feedback that the installation is correct. If the nozzle is not fully embedded or is tilted, the seal fails, leading to gas leakage. The sensor immediately detects abnormal pressure (low or fluctuating value) and promptly alerts the operator to investigate. This design fundamentally avoids the hidden error of "seemingly in place but actually loose" during manual installation, ensuring the precision of the nozzle's fit with the gas path and laying the foundation for accurate test data.

[0031] Dynamic early warning of pipe loosening, proactively ensuring gas path stability: When the equipment's airflow operates for a long time or is subjected to slight vibration, the first auxiliary pipe and the tapered pipe may shift or loosen, causing misalignment with the nozzle plate pipe. At this time, the moving ring will press against the edge of the first auxiliary pipe and the tapered pipe due to pipe misalignment. The metered gas injected by the pneumatic device will accumulate in the support ring due to the narrowing of the flow channel, and the air pressure sensor value will increase significantly, triggering the "position loosening" alarm. The above real-time monitoring function breaks through the passive mode of traditional equipment "discovering faults only after they occur". It can warn of potential risks before the gas path completely fails, avoid local eddies and sudden pressure changes caused by pipe misalignment, and ensure the continuity and stability of the testing process.

[0032] Simplifying troubleshooting processes and reducing maintenance costs: When equipment exhibits abnormal test data, traditional methods require checking multiple aspects such as nozzle installation, pipe sealing, and sensor accuracy one by one, which is time-consuming and complex. This design, however, uses "quantitative feedback" of air pressure values ​​to quickly pinpoint the problem type: if the air pressure remains consistently low, it's highly likely due to improper nozzle installation or worn seals; if the air pressure suddenly increases, it's often due to loose pipes or misaligned connections. Operators can narrow down the troubleshooting scope without disassembling the equipment, significantly shortening troubleshooting time. For batch testing scenarios, the aforementioned intelligent diagnostic function can reduce equipment downtime and lower maintenance costs.

[0033] Enhancing the equipment's automated closed-loop control capabilities to adapt to complex working conditions: This design integrates "switching-docking-detection-feedback" into a complete automated process; that is, when switching nozzle plates, a pneumatic device drives a moving ring with nozzle plates to move, and a pressure sensor synchronously monitors the docking status. If an abnormality is detected, the test is automatically paused and an alarm is issued, and operation resumes after the fault is cleared. The above-mentioned closed-loop control capability enables the equipment to ensure the reliability of each docking without human intervention; for batch testing scenarios in textile laboratories or factories, it can significantly improve work efficiency and reduce the testing risks caused by human operation.

[0034] 3. The third component of this invention adopts a combination design of involute and converging tubes. Compared with the defects of existing straight-through pipes that are prone to flow accumulation and velocity fluctuations, it achieves stable flow velocity control through gradient optimization of the airflow path, providing a more reliable measurement environment for the differential pressure sensor. The specific beneficial effects are as follows:

[0035] Achieving controllable velocity gradient and reducing turbulence interference: In straight-through pipes, the airflow velocity distribution is uneven, easily resulting in a fast velocity at the center and a slow velocity at the edges. This velocity difference creates turbulence, causing fluctuations in sensor data. The combination of involute and converging pipes, along with helical guide vanes and radial guide vanes, can achieve step-by-step control of the flow, first achieving uniform flow and then stabilizing the velocity. Specifically, the involute guides the airflow tangentially through the helical guide vanes, using centrifugal force to make the velocity distribution more uniform, similar to the stratified rectification of fluid in a centrifugal force field. Subsequently, the converging pipe contracts at a fixed taper, keeping the airflow in a laminar state during acceleration and avoiding turbulence. This design allows for a controllable gradient change in airflow velocity from the inlet to the outlet, with controllable velocity deviation, significantly improving the stability of differential pressure sensor measurements.

[0036] Adapting to a wide range of flow rate requirements and enhancing equipment versatility: Different fabrics exhibit significant differences in air permeability. Straight-through pipes, due to their limited flow velocity adjustment capabilities, are prone to overload turbulence at high flow rates and lack sensitivity at low flow rates. The combination of involute and tapered tubes, through adjustable structural parameters, achieves wide-range adaptability: For high flow rate scenarios, increasing the involute angle reduces airflow resistance, while the gradual contraction of the tapered tube prevents excessively high flow velocities; for low flow rate scenarios, decreasing the involute angle enhances airflow constraint, and the precise velocity control of the tapered tube ensures flow velocity stability at low flow rates. This flexibility allows the equipment to cover the testing needs of various fabrics without changing the pipes, improving its versatility and applicability.

[0037] 4. In this invention, the radial guide vanes, while fulfilling the function of flow equalization, also serve as reinforcing ribs of an involute tube, forming a dual optimization of "function and structure," which specifically brings the following significant beneficial effects:

[0038] Enhanced flow uniformity and improved airflow stability: Radial guide vanes are evenly distributed radially along the inner wall of the involute pipe. The vane plane is perpendicular to the airflow direction, which can break down the spiral airflow into multiple uniform airflows parallel to the pipe axis. Compared with bladeless pipes, it can reduce the velocity deviation of the airflow in the pipe and eliminate local high-speed or low-speed areas through physical separation and guidance. The above-mentioned flow uniformity effect directly improves the detection accuracy of the differential pressure sensor and avoids pressure fluctuations caused by uneven airflow distribution. Especially in the testing of low-permeability fabrics, it can capture small flow rate changes more accurately.

[0039] Enhanced pipe structure strength to resist airflow vibration and impact: Involute pipes are prone to resonance due to airflow pulsation when airflow passes through at high speed, which may lead to pipe fatigue deformation or even cracking after long-term use; the radial guide vanes are made of alloy material, with one end welded to the inner wall of the involute pipe and the other end converging at the center of the pipe to form a reinforced structure similar to wheel spokes; the above design improves the bending strength of the involute pipe, which can effectively offset the vibration energy generated by airflow impact, reduce wear or cracks in the pipe caused by long-term vibration, and extend the service life of the equipment;

[0040] Reduce airflow energy loss and lower system energy consumption: Traditional reinforcing ribs, if poorly designed, can become a source of airflow resistance, leading to increased energy loss; while the flat shape of the radial guide vanes and the smooth transition to the inner wall of the involute tube enhance the structure while having a smaller airflow resistance coefficient; the suction fan does not need to do extra work and will not increase the energy consumption of the equipment. Attached Figure Description

[0041] Figure 1 This is a structural diagram of the main body of the present invention;

[0042] Figure 2 This is a disassembled diagram of the first component of the present invention;

[0043] Figure 3 This is a top view of the main structure of the present invention;

[0044] Figure 4 This is a structural diagram related to the second and third components of the present invention;

[0045] Figure 5 This is a diagram showing the positional distribution of the frame, pneumatic device, connecting pipe, and support ring in this invention.

[0046] Figure 6 This is an exploded view of the relevant structure of the second component of the present invention;

[0047] Figure 7 This is a front sectional view of the main structure of the second component of the present invention;

[0048] Figure 8 This is a cross-sectional perspective view of the main structure of the second component of the present invention;

[0049] Figure 9 This is a structural diagram of the tapered tube and helical guide vane in this invention;

[0050] Figure 10 This is a structural diagram of the involute tube and radial guide vanes in this invention;

[0051] Figure 11 This is a front view of the involute and tapered tubes after being cut in this invention.

[0052] In the picture:

[0053] 1. Frame; 2. First assembly; 201. Support plate; 202. Auxiliary plate; 203. Snap-on cover; 204. Electric pressure rod; 205. Auxiliary ring; 206. Spring; 207. Guide rod; 208. Pressure head;

[0054] 3. Second component; 301. First auxiliary tube; 302. Embedded groove A; 303. Embedded groove B; 304. Servo motor; 305. Adjustment disc; 306. Pneumatic device; 307. Connecting pipe; 308. Support ring; 309. Moving ring; 310. Sealing gasket; 311. Airflow nozzle; 312. Strain gauge;

[0055] 4. Third component; 401. Support frame; 402. Second auxiliary tube; 403. Involute tube; 404. Converging tube; 405. Spiral guide vane; 406. Radial guide vane; 407. Differential pressure sensor. Detailed Implementation

[0056] 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.

[0057] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0058] Example

[0059] Please refer to Figures 1 to 8 As shown:

[0060] To address the problems mentioned in the technical solutions, this application provides a cashmere fabric air permeability testing device, including: a frame 1 and an airflow nozzle plate 311, and further including: a second component 3 for switching the airflow nozzle plate 311;

[0061] The second component 3 includes a first auxiliary pipe 301 fixedly connected to the frame 1. An embedded groove A302 is formed on the annular bottom surface of the first auxiliary pipe 301, and an embedded groove B303 is formed on the same vertical line as the embedded groove A302. A servo motor 304 is fixedly connected to the top wall of the inner cavity of the frame 1. An adjusting plate 305 is fixedly connected to the drive shaft end of the servo motor 304. Grooves are equidistantly arranged around the adjusting plate 305, and pneumatic devices 306 are fixedly connected to each groove. A connecting pipe 307 is fixedly connected to each pneumatic device 306. A support ring 308 is fixedly fitted around the disc 305 at equal intervals. A movable ring 309 is symmetrically slidably connected to the support ring 308. A sealing gasket 310 is fixedly connected to the outer end face of the movable ring 309. The plane where the connecting pipe 307 is located coincides with the middle plane of the support ring 308. Airflow nozzles 311 are all fixedly connected to the inner ring wall of the movable ring 309. The orifice size of the airflow nozzles 311, which are equidistantly distributed on the same plane of the adjusting disc 305, gradually increases clockwise. Strain gauges 312 are fixedly connected to the outer end face of the sealing gaskets 310.

[0062] It also includes a first component 2 fixed on the frame 1; the first component 2 includes a support piece 201 fixedly connected to the upper surface of the frame 1, an auxiliary piece 202 placed in the inner ring groove of the support piece 201, and a fastening cover 203 fastened to the outer periphery of the support piece 201; an electric pressure rod 204 is provided on the frame 1, an auxiliary ring 205 is fixedly connected to the outer end of the electric pressure rod 204, a spring 206 is fixedly connected at equal intervals to the bottom surface of the auxiliary ring 205, a pressure head 208 is fixedly connected to the bottom surface of the spring 206, and the top end of the pressure head 208 slides against the inner wall of the auxiliary ring 205; the bottom surface of the auxiliary ring 205 is provided with column grooves at equal intervals, and a guide rod 207 is fixedly connected at equal intervals to the bottom ring surface of the pressure head 208, the guide rod 207 is sleeved by the spring 206, and its top end slides in the column groove of the bottom surface of the auxiliary ring 205.

[0063] in:

[0064] The first component 2 is used for fabric fixation before air permeability testing.

[0065] The snap-fit ​​cover 203 is used to fasten and fix the fabric laid on the auxiliary piece 202 in conjunction with the support piece 201.

[0066] The second component 3 is used for switching airflow nozzle plates 311 with different orifice diameters.

[0067] The adjusting plate 305 has grooves at equal intervals, which are used to place the pneumatic device 306. A mesh plate is fastened to the groove to protect the pneumatic device 306.

[0068] The pneumatic device 306 is used to pump gas into the inner cavity of the support ring 308 through the connecting pipe 307; it is a small screw pump.

[0069] The airflow nozzle plate 311 is used in conjunction with the auxiliary plate 202 to change the initial state of the gas entering the airflow channel and adapt to fabrics with different breathability.

[0070] It should be noted that the selection of the nozzle diameter of the airflow nozzle 311 should be based on the air permeability of the sample. For samples whose air permeability is unclear, it is necessary to conduct several tests to more accurately reflect the air permeability of the sample.

[0071] The numerical change of strain gauge 312 can indirectly provide feedback on whether the pipe of the support ring 308 where the airflow nozzle 311 is located is successfully connected with the first auxiliary pipe 301 and the second auxiliary pipe 402; and whether the pipe installation is loose.

[0072] A further embodiment: Please refer to Figure 1 , Figure 4 , Figures 9 to 11 As shown:

[0073] The third component 4 includes a support frame 401 fixedly connected to the inner cavity of the frame 1. A second auxiliary pipe 402 is fixedly connected to the support frame 401. An involute pipe 403 is fixedly connected to the upper end of the second auxiliary pipe 402. A tapered pipe 404 is fixedly connected to the top end of the involute pipe 403 through a flange. An embedded groove B303 is opened on the top of the tapered pipe 404. A spiral guide vane 405 is fixedly connected inside the tapered pipe 404. Radial guide vanes 406 are fixedly connected at equal intervals to the inner wall of the involute pipe 403. A differential pressure sensor 407 is fixedly connected to the inner wall of the second auxiliary pipe 402.

[0074] in:

[0075] The third component 4 is used to avoid the situation where, when using a traditional straight-tube channel, the airflow is prone to form an uneven flow field due to inlet disturbances, wall friction, etc., such as high flow velocity at the center and low flow velocity at the edge, which leads to an increase in the measurement error of pressure difference / flow rate caused by uneven airflow distribution.

[0076] The second auxiliary pipe 402 is connected to the bottom end of other pipes and accessories of the test equipment.

[0077] The involute 403 has an inner diameter that gradually increases from top to bottom, while the tapered tube 404 has an inner diameter that gradually decreases from top to bottom; both the involute 403 and the tapered tube 404 are made of stainless steel.

[0078] In the prior art, after the differential pressure sensor 407 detects the change in air pressure, the instrument's CPU data processing center calculates the air permeability of the fabric based on the pressure difference between the two sides of the sample.

[0079] It should be noted that the principle of the combination of the involute tube 403 and the radial guide vane 406 is based on the fluid dynamics principle of the converging-expanding structure. According to Bernoulli's equation, when a fluid flows in a tube, the flow velocity is inversely proportional to the cross-sectional area.

[0080] In the narrowing section, the channel diameter gradually decreases, the cross-sectional area of ​​the airflow shrinks, and the flow velocity inevitably increases (kinetic energy increases). At the same time, the pressure decreases and potential energy is converted into kinetic energy. The above acceleration effect can quickly stabilize the initial state of the airflow and reduce measurement deviations caused by inlet airflow turbulence.

[0081] In the diffuser section, the channel diameter gradually increases, the flow velocity decreases, and the pressure increases. At this point, the airflow smoothly transitions from a high-speed state, avoiding direct impact on the sample surface and reducing turbulence generation.

[0082] Fluid control principle of guide vanes:

[0083] Spiral guide vane 405 (converging section):

[0084] Utilizing the principle of conservation of angular momentum, the blades guide the airflow to spiral along the central axis of the channel, forming a rotating flow field. This rotation generates centrifugal force between airflow particles, causing the turbulent airflow to become more orderly, similar to the stable circulation at the center of a typhoon, thereby suppressing turbulence and vortices. At the same time, the spiral motion lengthens the path of the airflow in the converging section, making the velocity change more uniform and avoiding local turbulence caused by sudden acceleration.

[0085] Radial guide vanes 406 (gradually expanding section):

[0086] Employing the principle of fluid diversion, the blades are evenly distributed radially, "breaking down" the spiral flow into multiple streams of airflow parallel to the channel axis. This radial structure ensures that the high-speed rotating airflow is evenly dispersed during expansion, guaranteeing that the airflow moves vertically and stably, avoiding localized pressure fluctuations caused by airflow deviation; such as excessively high edge airflow velocity and insufficient central velocity.

[0087] The working principle of all the content in the above embodiments is as follows:

[0088] In the initial state:

[0089] Spring 206 is in a normal relaxed state and is not compressed; moving ring 309 does not move with sealing gasket 310 into either inner groove A302 or inner groove B303; strain gauge 312 does not abut against the inner groove wall and the outer surface of first auxiliary tube 301 and tapering tube 404.

[0090] The following describes the working process of Component 2 and Component 3:

[0091] In use, the test sample is first placed on the auxiliary plate 202 that is adapted to the sample, and then the fastening cover 203 is fastened on the support plate 201 to fix the sample. Further, the electric pressure rod 204 is controlled by the equipment to drive the auxiliary ring 205 to move. The moving auxiliary ring 205 will bring the pressure head 208 on it to press down on the sample. At this time, the spring 206 and the guide rod 207 provide assistance for the clamping of the sample.

[0092] Furthermore, after the above operations are completed, the second component 3 is controlled by the main controller of the equipment to perform the matching airflow nozzle 311 docking operation; specifically, the servo motor 304 will rotate the adjustment disk 305 to move the airflow nozzle 311 adapted to the test sample to the vertical line where the first auxiliary tube 301 is located. Then, the pneumatic device 306 is started, and the pneumatic device 306 will deliver a certain amount of gas to the cavity of the support ring 308 through the connecting pipe 307. At this time, the moving ring 309 in the cavity of the support ring 308 will move into the inner groove A302 and the inner groove B303 respectively under the action of the gas, and finally move into the inner groove to form an airflow passage with the first auxiliary tube 301, the tapered tube 404, the involute tube 403, and the second auxiliary tube 402.

[0093] Furthermore, there are two scenarios in the aforementioned docking process;

[0094] If the connection is normal, the pipe consisting of the support ring 308 and the moving ring 309 where the airflow nozzle plate 311 is located will smoothly enter the inner groove. At this time, under the premise that the pneumatic device 306 supplies gas in a quantitative manner, the air pressure sensor value in the support ring 308 will be relatively small.

[0095] If there is a problem with the connection, that is, when the first auxiliary pipe 301 and the tapering pipe 404 are loose, the moving ring 309 in the pipe composed of the support ring 308 and the moving ring 309 will abut against the first auxiliary pipe 301 and the tapering pipe 404. At this time, under the premise that the pneumatic device 306 supplies gas in a fixed amount, the value of the air pressure sensor in the support ring 308 will be large.

[0096] That is, the feedback from the air pressure sensor inside the aforementioned support ring 308 allows for real-time monitoring of the docking status during the docking process;

[0097] Please refer to the above work process. Figures 1 to 8 .

[0098] The following is the working process of the third component 4:

[0099] Furthermore, after the sample is fixed and the pipe is connected, the air permeability test can be performed. Specifically, when the gas passes from the sample into the converging tube 404, as the channel diameter gradually decreases and the cross-sectional area of ​​the airflow shrinks, the acceleration effect can quickly stabilize the initial state of the airflow and reduce measurement deviations caused by inlet airflow turbulence. At the same time, with the assistance of the spiral guide vanes 405, their spiral structure guides the airflow to move spirally along the central axis of the channel, forming a rotating flow field. The rotation generates centrifugal force between airflow particles, causing the turbulent airflow to become more orderly, thereby suppressing turbulence and vortices. Meanwhile, the spiral motion lengthens the path of the airflow in the converging section, making the velocity change more uniform and avoiding local turbulence caused by sudden acceleration.

[0100] Furthermore, as the airflow continues to move, it will move into the involute 403. With its gradually increasing channel diameter, the airflow velocity will decrease, allowing for a smooth transition from high speed and reducing turbulence. Assisted by the radially distributed guide vanes 406, the evenly distributed radial vanes break down the slower spiral flow into multiple streams parallel to the channel axis, ensuring the airflow moves vertically and stably, avoiding local pressure fluctuations caused by airflow deviation, such as excessively high edge velocity or insufficient center velocity. At this point, the differential pressure sensor 407 in the second auxiliary tube 402 can effectively detect these fluctuations.

[0101] Please refer to the above work process. Figure 1 , Figure 4 , Figures 9 to 11 .

[0102] Overview: During the relevant testing process, the airflow nozzle 311 is located inside the gas pipeline composed of the first auxiliary pipe 301, the support ring 308, the moving ring 309, the tapered pipe 404, the involute pipe 403, and the second auxiliary pipe 402. The suction fan in the equipment is connected to the lower end of the gas pipeline. The test sample is located at the upper end of the airflow chamber of the gas pipeline, that is, placed on the auxiliary plate 202 and pressed by the snap-on cover 203. The airflow nozzles 311 are distributed at radially equidistant positions on the adjustment plate 305. The airflow nozzles 311 can be automatically changed by controlling the rotation of the adjustment plate 305 through the CPU of the equipment.

[0103] The suction fan and the airflow nozzle 311 work in conjunction with each other. During testing, the suction fan starts, creating a vacuum below atmospheric pressure at the lower end of the airflow chamber, forming an airflow channel inside the chamber. The airflow enters from the pressure head 208 at the upper end of the airflow chamber, passes through the sample and the airflow nozzle 311, and is finally drawn out by the suction fan. During this process, the suction fan adjusts the suction volume to achieve a set pressure difference on both sides of the sample. Simultaneously, based on the orifice diameter of the airflow nozzle 311 and the magnitude of the pressure difference on both sides, the instrument's CPU data processing center calculates the air permeability of the fabric.

[0104] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0105] Although embodiments of the 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 invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for testing the air permeability of cashmere fabrics, comprising: The frame (1) and the airflow nozzle plate (311) are characterized in that they further include a second component (3) for switching the airflow nozzle plate (311). The second component (3) includes a first auxiliary tube (301) fixedly connected to the frame (1). An embedded groove A (302) is provided on the annular bottom surface of the first auxiliary tube (301), and an embedded groove B (303) is provided on the same vertical line as the embedded groove A (302). A servo motor (304) is fixedly connected to the top wall of the inner cavity of the frame (1). An adjustment disk (305) is fixedly connected to the drive shaft end of the servo motor (304). Grooves are equidistantly arranged around the adjustment disk (305). A pneumatic device (306) is fixedly connected to each groove of the adjustment disk (305). A connecting pipe (307) is fixedly connected to the pneumatic device (306). The adjustment disc (305) is equidistantly fitted and fixed with a support ring (308), and a movable ring (309) is symmetrically slidably connected to the support ring (308). A sealing gasket (310) is fixedly connected to the outer end face of the movable ring (309). The plane where the connecting pipe (307) is located coincides with the middle plane of the support ring (308). The airflow nozzles (311) are all fixedly connected to the inner ring wall of the moving ring (309). The aperture of the airflow nozzles (311) that are equidistantly distributed on the same plane of the adjusting plate (305) gradually increases clockwise. The outer end face of the sealing gasket (310) is fixedly connected to the strain gauge (312).

2. The air permeability testing device for cashmere fabrics according to claim 1, characterized in that: It also includes a first component (2) fixed on the frame (1); The first component (2) includes a support piece (201) fixedly connected to the upper surface of the frame (1), an auxiliary piece (202) is placed in the inner ring groove of the support piece (201), and a fastening cover (203) is fastened to the outer periphery of the support piece (201). An electric pressure rod (204) is provided on the frame (1). An auxiliary ring (205) is fixedly connected to the outer end of the electric pressure rod (204). Springs (206) are fixedly connected at equal intervals to the bottom surface of the auxiliary ring (205). A pressure head (208) is fixedly connected to the bottom surface of the spring (206). The top end of the pressure head (208) slides against the inner wall of the auxiliary ring (205). The bottom surface of the auxiliary ring (205) is provided with column grooves at equal intervals. The bottom ring surface of the pressure head (208) is fixedly connected with guide rods (207) at equal intervals. The guide rods (207) are sleeved by springs (206), and their top ends slide in the column grooves on the bottom surface of the auxiliary ring (205).

3. The air permeability testing device for cashmere fabrics according to claim 1, characterized in that: It also includes a third component (4) located inside the cavity of the frame (1); The third component (4) includes a support frame (401) fixedly connected to the inner cavity of the frame (1), a second auxiliary tube (402) fixedly connected to the support frame (401), and an involute tube (403) fixedly connected to the upper end of the second auxiliary tube (402). The top end of the involute (403) is fixedly connected to the tapered tube (404) via a flange, and the inner groove B (303) is opened on the top of the tapered tube (404).

4. The air permeability testing device for cashmere fabrics according to claim 3, characterized in that: A spiral guide vane (405) is fixedly connected inside the tapered tube (404), and radial guide vanes (406) are fixedly connected at equal intervals on the inner wall of the involute tube (403). A differential pressure sensor (407) is fixedly connected to the inner wall of the second auxiliary tube (402).

5. The air permeability testing device for cashmere fabrics according to claim 2, characterized in that: A sealing sheet is fixed to the bottom surface of the pressure head (208).

6. The air permeability testing device for cashmere fabrics according to claim 1, characterized in that: The pneumatic device (306) is a small screw pump; a pressure sensor is installed inside the support ring (308).

7. The air permeability testing device for cashmere fabrics according to claim 3, characterized in that: The involute tube (403) has an inner diameter that gradually increases from top to bottom, while the converging tube (404) has an inner diameter that gradually decreases from top to bottom.

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