Breathable sound transmission element internal pore measuring device and air pressure slow rise testing system

Abstract

The invention relates to the technical field of explosion-proof product design and detection authentication, in particular to an air-permeable sound-transmitting element internal pore measuring device and an air pressure slow rising testing system.The testing system comprises an air cylinder and an air inlet measurement and control unit, and the air inlet measurement and control unit is connected with the air-permeable sound-transmitting element internal bubble pore diameter measuring device; the measuring device comprises a liquid cover and an air seat which are detachably connected, and the breathable sound transmission element is installed between the liquid cover and the air seat. The device is simple and reliable in structure, only test liquid needs to be added into the liquid adding tank of the liquid cover when the pore diameter of the sample bubble is measured, the whole sample and the mounting structure thereof are prevented from being integrally immersed into the test liquid, the consumption of the test liquid is remarkably reduced, the test system is high in automation degree, the test air pressure rises slowly and stably, and the adjusting precision is high; the difficulty that the air pressure value is difficult to perceive and record when the first bubble appears in the test process is overcome, and the measurement quality and the test efficiency of the pore diameter of the bubbles in the breathable sound transmission element are greatly improved.

Description

Technical Field

[0001] This application relates to the field of explosion-proof product design and testing certification technology, and in particular to a device for measuring the internal pore size of a breathable sound transmission element and a test system for slow air pressure rise. Background Technology

[0002] This type of permeable sound-transmitting element is widely used inside explosion-proof products such as combustible gas sensors / detectors and horns. Its main function is to facilitate the exchange of combustible gases in the surrounding environment with the gas inside the explosion-proof enclosure, thereby enabling internal components to analyze gas concentrations. It can also transmit sound waves from the internal sound-generating device, discharge liquids, and maintain the integrity of the product's explosion-proof design. The internal pores of these elements cannot be directly measured, but their size is highly relevant to the product's explosion-proof performance, making it crucial in the design, application, and testing certification of explosion-proof products.

[0003] The internal pore size of breathable sound-transmitting elements is closely related to their explosion-proof performance and is crucial in the design, application, and testing certification of explosion-proof products, but it cannot be directly measured. Appendix B of GB / T 3836.2-2021 clearly stipulates that the maximum bubble test pore diameter (pore size) should be measured according to the method specified in standard GB / T 5249.

[0004] The schematic diagram of bubble test aperture measurement as specified in GB / T 5249 is shown below. Figure 1 As shown, the principle is as follows: The sample (air-permeable sound transmission element) is completely wetted with the test liquid, and then the sample is sealed and immersed in the test liquid. Gas is introduced from the other side of the sample, and the gas pressure is gradually increased. The sample surface is observed, and the test gas pressure value is recorded when the first bubble appears. The bubble test pore diameter is the maximum equivalent capillary diameter of the sample. Based on this pressure value and parameters such as the height of the test liquid surface from the sample surface and the surface tension of the test liquid, the bubble test pore diameter inside the sample can be calculated.

[0005] In the aforementioned aperture measurement process, the sample and its mounting structure are usually immersed in the test liquid. This process requires a large container for the test liquid and a large amount of test liquid.

[0006] Furthermore, because the measurement principle utilizes the surface tension of the test liquid, the measurement process is highly sensitive to the test air pressure, requiring high precision in air pressure regulation. During the measurement process, the test air pressure often rises too quickly, resulting in the appearance of multiple bubbles. This makes it impossible to accurately record the critical air pressure value at the appearance of the first bubble, causing the measured bubble aperture of the air-permeable sound transmission element to be inaccurate. Summary of the Invention

[0007] The purpose of this application is to provide a measuring device and testing system for the internal bubble pore size of a breathable sound transmitting element. It employs a novel sample mounting structure, designing only a trough for adding test liquid above the sample (breathable sound transmitting element), thus avoiding immersing the entire sample and its mounting structure in the test liquid and significantly reducing test liquid consumption. The test air pressure is regulated using a combination of a mass flow controller and an air storage tank, resulting in a slower and more stable rise in test air pressure. This facilitates recording the critical air pressure value at the appearance of the first bubble, improving the accuracy of test air pressure regulation and greatly enhancing the measurement quality and testing efficiency of the internal bubble pore size of the breathable sound transmitting element.

[0008] To achieve the above objectives, the present invention provides a measuring device for the pore size of air-permeable sound transmission elements, comprising a detachably connected liquid cap and an air seat. The top of the air seat has a support platform capable of supporting the sound transmission element. The support platform has a downwardly recessed air cavity groove at its center. The bottom of the air seat has an air passage, one end of which is connected to the air cavity groove, and the other end extends outside the air seat. The liquid cap is fitted onto the top of the air seat and covers the support platform. A liquid filling groove is provided inside the liquid cap, penetrating the top and bottom of the liquid cap. An annular mounting groove is provided at the bottom of the liquid cap. The annular mounting groove and the support platform form a mounting cavity capable of pressing in the air-permeable sound transmission element, and the air-permeable sound transmission element can separate the liquid filling groove from the air cavity groove.

[0009] To facilitate the assembly and disassembly of the liquid cap and the gas seat, the support platform is a cylindrical structure with external threads on its outer wall and internal threads on the bottom of the liquid cap, which are threaded together with the support platform.

[0010] To facilitate the relative rotation of the liquid cap and the gas seat, a handle capable of driving their rotation is provided on the outside of both the liquid cap and the gas seat.

[0011] To prevent the liquid cap and gas seat from damaging the sample during disassembly and assembly, the diameter of the annular mounting groove is less than or equal to the outer diameter of the support platform.

[0012] To ensure airtightness during testing, sealing gaskets are provided on the bottom surface of the annular mounting groove and / or the top surface of the support platform.

[0013] To facilitate connection between the air passage and the measurement system, the inner wall of the end of the air passage that communicates with the outside is provided with an internal thread.

[0014] The present invention also provides a slow-rise air pressure measurement system for a measuring device for measuring the internal bubble pore size of the above-mentioned breathable sound transmission element, comprising a gas cylinder and an air intake control unit, wherein the gas cylinder is connected to the air intake control unit, and the air intake control unit is connected to the air passage of the measuring device for measuring the internal bubble pore size of the breathable sound transmission element.

[0015] To facilitate intake regulation, the intake measurement and control unit includes a filter, a pressure regulating valve, a mass flow controller, an air storage tank, and a pressure transmitter connected in sequence.

[0016] In summary, the present invention has the following beneficial effects: the measuring device for the internal bubble pore diameter of the air-permeable sound transmission element has a simple and reliable structure. When measuring the bubble pore diameter of the sample, only the test liquid needs to be added to the liquid filling tank of the liquid cap, avoiding the need to immerse the entire sample and its installation structure in the test liquid, which significantly reduces the consumption of test liquid. The testing system has a high degree of automation, the test air pressure rises slowly and stably, and the adjustment accuracy is high. It overcomes the difficulty of detecting and recording the air pressure value when the first bubble appears during the test, and greatly improves the measurement quality and testing efficiency of the bubble pore diameter of the air-permeable sound transmission element. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a bubble test aperture measuring device for air-permeable sound transmission elements in the prior art; Figure 2 This is a schematic diagram of the structure of the internal bubble pore size measuring device of the air-permeable sound transmission element of the present invention; Figure 3 This is a schematic diagram of the air pressure slowly rising test system of the air permeable sound transmission element internal bubble pore diameter measuring device of the present invention. Detailed Implementation

[0018] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0019] Example 1: like Figure 2 The device shown is for measuring the pore size of air-permeable sound transmission elements, including a detachably connected liquid cap 1 and an air seat 2. Specifically, the top of the air seat 2 has a support platform that can support the breathable sound transmission element 3. The support platform is a cylindrical structure with external threads on the outer wall of the support platform. The bottom of the liquid cover 1 has internal threads. The liquid cover 1 is threadedly connected to the support platform, so that the liquid cover 1 and the air seat 2 can be detached. In addition, the liquid cover 1 and the air seat 2 are respectively provided with handles 6 that can drive them to rotate. The support platform has a downwardly recessed air cavity groove 9 in the center, and the bottom of the air seat 2 has an air passage 4. One end of the air passage 4 is connected to the air cavity groove 9, and the other end extends to the outside of the air seat 2. The inner wall of the end of the air passage 4 that is connected to the outside is provided with an internal thread, which is connected to the air pipe connector 5 through the internal thread. The liquid cover 1 is fitted onto the top of the air seat 2 and covers the support platform. A liquid filling groove 8 is provided inside the liquid cover 1, which extends through the top and bottom of the liquid cover 1. An annular mounting groove is provided at the bottom of the liquid cover 1. The diameter of the annular mounting groove is less than or equal to the outer diameter of the support platform. An installation cavity is formed between the annular mounting groove and the support platform, which can press and install the ventilated sound transmission element 3. The ventilated sound transmission element 3 can separate the liquid filling groove 8 from the air cavity groove 9. Sealing gaskets 7 are respectively provided on the bottom surface of the annular mounting groove and / or the top surface of the support platform to ensure the sealing between the liquid filling groove 8 and the air cavity groove 9 after the ventilated sound transmission element 3 is installed.

[0020] During testing, the fully soaked air-permeable sound transmission element 3 sample is placed on the support platform. The air seat 2 and liquid cap 1 are tightened by the handle 6, and the sample is sealed by the sealing gasket 7 at the connecting end face. The test liquid is introduced into the liquid filling tank 8 of the liquid cap 1. The air pipe is connected to the air passage 4 of the air seat 2 and the gas is slowly introduced into the air chamber 9, so that the air pressure in the air chamber 9 rises slowly. The surface of the sample is observed, and the test gas pressure value is recorded when the first bubble appears.

[0021] Example 2: like Figure 3 As shown, the present invention also provides a pressure slowly rising measurement system for a measuring device for measuring the internal bubble pore size of the above-mentioned air-permeable sound transmission element, including a gas cylinder 10 and an air intake measurement and control unit. The air intake measurement and control unit includes a filter 11, a pressure regulating valve 12, a mass flow controller 14, a gas storage tank 15, and a pressure transmitter 16 connected in sequence. The gas cylinder 10 is connected to the filter 11. The mass flow controller 14 is connected to the air passage of the measuring device for measuring the internal bubble pore size of the air-permeable sound transmission element through a gas pipeline. In addition, a first solenoid valve 13 is provided at the inlet end of the mass flow controller 14, and a second solenoid valve 17 is provided at the outlet end of the gas storage tank 15. The air intake measurement and control unit also has a human-machine interface 18 and a controller 19.

[0022] The air intake control unit of the measurement system can be integrated into a single cabinet as needed. The mass flow controller 14 is used to regulate the gas flow rate entering the gas storage tank 15, thereby controlling the gas pressure in the gas chamber. The gas storage tank 15 is connected to the gas seat's air passage, forming a larger enclosed space, which further reduces the rate of increase in gas pressure in the gas chamber and improves the accuracy of test gas pressure regulation. The pressure regulating valve 12 is used to stabilize the high-pressure gas from the gas cylinder 10 or other gas sources within the pressure range required for the normal operation of the mass flow controller 14, ensuring the normal operation of the mass flow controller 14. The pressure transmitter 16 is used to measure the pressure of the test gas, and the second solenoid valve 17 is used to discharge the test gas from the gas storage tank 15 after measurement.

[0023] The controller 19 and human-machine interface 18 (touch screen) in the air intake measurement and control unit of the measurement system can realize the electrical control and human-machine interaction of the entire device, effectively complete the relevant test process and experimental data acquisition and storage, and have a communication interface to communicate with other devices.

[0024] The measurement system uses a combination of a mass flow controller 14 and a gas storage tank 15 to adjust the inlet flow rate and pressure of the test gas. This allows the gas pressure in the gas chamber below the sample to rise more slowly and stably, with high adjustment accuracy. It greatly reduces the rate of rise of the test gas pressure, making it easier to detect and record the gas pressure value when the first bubble appears during the test. It also makes it easier to accurately record the critical gas pressure value when the first bubble appears, resulting in more accurate measurement results. The gas storage tank 15 is connected to the gas cavity under the sample to form a larger cavity. At the same time, the internal volume of the gas storage tank 15 is much larger than the volume of the gas cavity, which effectively improves the stability and applicability of the device adjustment parameters and reduces the influence of the gas cavity size change caused by different sample sizes on the gas pressure rise rate in the gas cavity. The specially designed installation structure of the sample measuring device eliminates the need to immerse the entire installation unit in the test liquid during the measurement process. Only a small amount of test liquid needs to be added to the liquid cap, which greatly reduces the consumption of test liquid during the measurement process.

[0025] The use of controller 19, human-machine interface 18 (touch screen), pressure transmitter 16, mass flow controller 14, solenoid valve, etc., improves the automation level of the device and enhances measurement quality and testing efficiency.

[0026] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape, principle and application direction of this application should be covered within the scope of protection of this application.

Claims

1. A device for measuring the pore size of air-permeable sound transmission elements, characterized in that: The device includes a detachably connected liquid cap and an air seat. The top of the air seat has a support platform that can support a sound transmission element. The support platform has a downwardly recessed air cavity groove in its center. The bottom of the air seat has an air passage. One end of the air passage is connected to the air cavity groove, and the other end extends outside the air seat. The liquid cap is fitted onto the top of the air seat and covers the support platform. The liquid cap has a liquid filling groove inside, which extends through the top and bottom of the liquid cap. The bottom of the liquid cap has an annular mounting groove. The annular mounting groove and the support platform form a mounting cavity that can press-fit a breathable sound transmission element. The breathable sound transmission element can separate the liquid filling groove from the air cavity groove.

2. The measuring device for the internal bubble pore size of the air-permeable sound transmission element according to claim 1, characterized in that: The support platform is a cylindrical structure with external threads on its outer wall and internal threads on the bottom of the liquid cover. The liquid cover is threadedly connected to the support platform.

3. The measuring device for the internal bubble pore size of the air-permeable sound transmission element according to claim 2, characterized in that: The liquid cap and the gas seat are each provided with a handle that can drive them to rotate.

4. The measuring device for the internal bubble pore size of the air-permeable sound transmission element according to claim 2, characterized in that: The diameter of the annular mounting groove is less than or equal to the outer diameter of the support platform.

5. The measuring device for the internal bubble pore size of the air-permeable sound transmission element according to claim 1, characterized in that: The bottom surface of the annular mounting groove and / or the top surface of the support platform are respectively provided with sealing gaskets.

6. The measuring device for the internal bubble pore size of the air-permeable sound transmission element according to claim 1, characterized in that: The inner wall of the end of the air passage that connects to the outside is provided with internal threads.

7. A slow-rise air pressure testing system for a measuring device for the internal bubble pore size of a breathable sound-transmitting element as described in any one of claims 1-6, characterized in that: It includes a gas cylinder and an air intake measurement and control unit. The gas cylinder is connected to the air intake measurement and control unit, and the air intake measurement and control unit is connected to the air passage of the air-permeable sound transmission element's internal bubble pore diameter measuring device.

8. The measuring system for measuring the pore size of air-permeable sound transmission elements according to claim 7, characterized in that: The intake control unit includes a filter, a pressure regulating valve, a mass flow controller, an air storage tank, and a pressure transmitter connected in sequence.

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