A test device for bidirectional tightness testing

Abstract

The application discloses a test device for bidirectional sealing test, a box body is sealingly connected with a cover plate to form a first pressure chamber; an inflation valve support is sealingly installed on the outer wall of the box body to form a second pressure chamber; a breathing valve mounting interface is arranged on the box body and used for mounting a breathing valve assembly to be tested, so that the breathing valve assembly is in communication with the first pressure chamber and the second pressure chamber on two sides; a first air pressure adjusting circuit is in communication with the first pressure chamber, a second air pressure adjusting circuit is in communication with the second pressure chamber, the two circuits are independent and continuously adjust the air pressure of the chambers to simulate a dynamic pressure difference working condition; a first air leakage indicating valve is in communication with the first pressure chamber, a second air leakage indicating valve is in communication with the second pressure chamber, and the opening pressures are matched with the inhalation threshold value and the exhalation threshold value of the breathing valve respectively. Through the double-chamber structure and the independent air pressure adjusting circuit, the bidirectional sealing test of the breathing valve assembly under the dynamic pressure difference working condition is realized, and the exhaust phenomenon of the air leakage indicating valve is used to directly capture the opening moment of the breathing valve.

Description

Technical Field

[0001] This invention belongs to the field of sealing test technology, and mainly relates to a test device for bidirectional sealing test, used for bidirectional sealing test of breather valve assembly for sealing cavity of precision optical instrument. Background Technology

[0002] Optoelectronic pods, as optoelectronic devices carried on aviation platforms such as fixed-wing aircraft and drones, integrate high-precision optical sensors such as visible light cameras, infrared thermal imagers, and laser rangefinders. These optical sensors have strict requirements for their working environment and typically need to operate in a sealed, dry cavity to prevent external factors such as dust and moisture from interfering with the optical imaging quality.

[0003] During flight missions, changes in the aircraft's altitude cause significant alterations in atmospheric pressure. According to the principles of gas pressure, as altitude increases, external atmospheric pressure decreases, creating a positive pressure difference between the sealed cavity and the outside; conversely, as altitude decreases, external atmospheric pressure increases, creating a negative pressure difference between the cavity and the outside. This repeated pressure difference caused by altitude variations can stress the optical window of the optoelectronic pod, potentially leading to window distortion and consequently, optical imaging distortion and decreased measurement accuracy. In severe cases, continuous pressure stress can also cause fatigue damage to the sealing structure, reducing the equipment's lifespan and reliability.

[0004] To address the aforementioned issues, existing technologies typically install a breathing valve assembly on the sealed shell of the optoelectronic pod. This assembly is a device with bidirectional air pressure regulation capabilities. Its working principle is as follows: when the pressure difference between the inside and outside reaches a preset threshold, the breathing valve automatically opens, allowing for slow gas exchange between the inside and outside of the cavity, thereby achieving pressure balance; when the pressure difference returns to a safe range, the breathing valve automatically closes, restoring the seal. In this way, the breathing valve assembly can effectively reduce pressure stress caused by altitude changes, protecting the optical window profile and the overall structural stability.

[0005] The breathing valve assembly's bidirectional adjustment capability includes two functions: exhalation, where gas is expelled from the inside when the internal pressure is higher than the external pressure and the pressure difference reaches a set value; and inhalation, where gas enters from the outside when the external pressure is higher than the internal pressure and the pressure difference reaches a set value. In practical applications, considering the lower atmospheric humidity at high altitudes and the higher humidity at low altitudes, the activation threshold for the inhalation function is usually set higher than that for the exhalation function to minimize the entry of external moisture into the cavity and prevent frost formation on the optical window surface.

[0006] However, current testing methods for the bidirectional sealing performance of breathing valve assemblies are not yet perfect. Existing testing methods mostly involve installing the breathing valve onto the actual pod shell for overall testing, or using simple inflation tools for unilateral pressurization testing, which has the following technical problems:

[0007] First, it cannot simulate the dynamic change of pressure difference caused by changes in flight altitude. In actual flight, air pressure changes are a continuous and slow gradual process, while existing testing devices mostly use a "step-like" pressurization method, directly inflating to the target pressure, which cannot simulate the complete gradual change of pressure difference from zero to the threshold, and thus cannot truly reflect the response characteristics of the breathing valve under actual operating conditions.

[0008] Second, it cannot achieve synchronous control of air pressure on both sides. In actual use, the air pressure on both sides of the breathing valve changes simultaneously, but the existing testing device only controls the air pressure on one side, while the other side is open to the atmosphere. It cannot simulate the complex scenario of "simultaneous changes on both sides", and the test conditions differ from the real working conditions.

[0009] Third, it is difficult to accurately capture the pressure difference at the moment the breathing valve opens. Since the opening of the breathing valve is a dynamic process that changes continuously with the pressure difference, its opening pressure needs to be captured in real time during this process. However, traditional testing devices mostly use static readings, meaning the operator can only read the pressure gauge value after the pressure has stabilized. This makes it impossible to know the precise pressure difference at the moment the valve first opens, leading to significant errors in the test results.

[0010] Therefore, there is an urgent need for a specialized testing device that can simulate the dynamic working conditions of pressure difference caused by changes in the flight altitude of a carrier aircraft and can independently test the bidirectional sealing performance of the breather valve, so as to meet the engineering requirements of precision optical equipment such as optoelectronic pods for testing the performance of breather valve components. Summary of the Invention

[0011] The purpose of this invention is to provide a test device for bidirectional sealing performance testing. This device can simulate the external scenario of real-time pressure difference changes caused by changes in the flight altitude of the carrier aircraft, realize bidirectional sealing performance testing of the breathing valve assembly under dynamic pressure difference conditions, quickly verify the air intake and exhaust regulation capabilities of the breathing valve, and ensure that its bidirectional sealing performance meets the requirements of actual use indicators.

[0012] To achieve the above objectives, the present invention provides a test apparatus for bidirectional sealing performance testing, comprising:

[0013] The housing (1) has a first pressure chamber inside it;

[0014] A cover plate (2) is installed in a sealed manner at the opening end of the housing (1);

[0015] An inflation valve bracket (3) is sealed and installed on the outer wall of the box (1), forming a second pressure chamber between the bracket and the outer wall of the box (1);

[0016] A breathing valve mounting interface is provided on the housing (1) for sealing and mounting the breathing valve assembly (9) under test, so that the two sides of the breathing valve assembly (9) under test are respectively connected to the first pressure chamber and the second pressure chamber;

[0017] The first air pressure regulating circuit is connected to the first pressure chamber and is used to independently and continuously regulate the air pressure in the first pressure chamber.

[0018] The second air pressure regulating circuit is connected to the second pressure chamber and is used to independently and continuously regulate the air pressure in the second pressure chamber.

[0019] The first venting indicator valve (6-1) is connected to the first pressure chamber and is used to automatically open the venting valve when the air pressure in the first pressure chamber reaches a preset value.

[0020] The second venting indicator valve (6-2) is connected to the second pressure chamber and is used to automatically open the venting valve when the air pressure in the second pressure chamber reaches a preset value.

[0021] The first pressure regulating circuit and the second pressure regulating circuit can independently and continuously regulate the pressure of the first pressure chamber and the second pressure chamber, so that a dynamic pressure difference is formed between them to simulate the dynamic pressure difference process that the tested breathing valve assembly (9) is subjected to in actual working conditions; the exhaust phenomenon of the first venting indicator valve (6-1) and the second venting indicator valve (6-2) are used to indicate the opening time of the inhalation function and the exhalation function of the tested breathing valve assembly (9), respectively.

[0022] In a further preferred embodiment, the housing (1) is integrally formed from aluminum alloy, with a closed bottom and an open top. The open end face is provided with a sealing groove (1-2) and a threaded hole (1-1), and the side is provided with an installation interface for installing the first air pressure regulating circuit interface, the first air release indicator valve (6-1) and the air filling valve bracket (3).

[0023] In a further preferred embodiment, the inflation valve bracket (3) is provided with a connection hole corresponding to the housing (1), a hole for installing the second air pressure regulating circuit interface, and a hole for installing the second venting indicator valve (6-2), and is sealed to the housing (1) through a sealing rubber strip (8).

[0024] In a further preferred embodiment, the first air pressure regulating circuit includes a first one-way inflation valve (4-1) and a first adjustable pressure reducing valve (11-1). The first one-way inflation valve (4-1) is sealed and installed on the housing (1) and communicates with the first pressure chamber. The first adjustable pressure reducing valve (11-1) is installed on the high-pressure gas cylinder (10-1) and connected to the first one-way inflation valve (4-1) via a hose (12-1). The second air pressure regulating circuit includes a second one-way inflation valve (4-2) and a second adjustable pressure reducing valve (11-2). The second one-way inflation valve (4-2) is sealed and installed on the inflation valve bracket (3) and communicates with the second pressure chamber. The second adjustable pressure reducing valve (11-2) is installed on the high-pressure gas cylinder (10-2) and connected to the second one-way inflation valve (4-2) via a hose (12-2).

[0025] In a further preferred embodiment, both the first adjustable pressure reducing valve (11-1) and the second adjustable pressure reducing valve (11-2) are manual knob-type precision pressure reducing valves, each equipped with a pressure gauge to display the air pressure value of its respective chamber in real time.

[0026] In a further preferred embodiment, the opening pressure of the first vent indicator valve (6-1) is preset to be equal to the inhalation threshold of the tested breathing valve assembly (9), and the opening pressure of the second vent indicator valve (6-2) is preset to be equal to the exhalation threshold of the tested breathing valve assembly (9).

[0027] In a further preferred embodiment, static sealing is achieved between the cover plate (2) and the box body (1) and between the inflation valve bracket (3) and the box body (1) by installing sealing rubber strips (8) in the sealing groove; the breathing valve assembly (9) is sealed to the box body (1) by pressing its own rubber pad with the breathing valve screw (7).

[0028] A method for conducting a bidirectional sealing test using the aforementioned testing apparatus includes the following steps:

[0029] Expiratory function test: Keep the second pressure chamber at normal pressure, and continuously and slowly increase the pressure to the first pressure chamber through the first pressure regulation circuit, so that the pressure difference between the first pressure chamber and the second pressure chamber gradually increases from zero. At the same time, observe the second venting indicator valve (6-2). When the second venting indicator valve (6-2) is observed to release air, record the pressure difference between the first pressure chamber and the second pressure chamber at this time, which is the expiratory opening threshold of the tested breathing valve assembly (9).

[0030] Inspiratory function test: Keep the first pressure chamber at normal pressure, and continuously and slowly increase the pressure to the second pressure chamber through the second pressure regulation circuit, so that the pressure difference between the second pressure chamber and the first pressure chamber gradually increases from zero. At the same time, observe the first vent indicator valve (6-1). When the first vent indicator valve (6-1) is observed to vent, record the pressure difference between the second pressure chamber and the first pressure chamber at this time, which is the inspiratory opening threshold of the tested breathing valve assembly (9).

[0031] A further preferred option is to block the first venting indicator valve (6-1) before conducting the expiratory function test and to block the second venting indicator valve (6-2) before conducting the inspiratory function test.

[0032] In a further preferred embodiment, the rate of continuous slow pressurization is controlled below 0.5 kPa / second to simulate the gradual change of air pressure; before the test begins, the pressure in both chambers is released to balance with the external atmospheric pressure by opening the pressure relief port of the venting indicator valve, ensuring that the initial pressure in both chambers is normal pressure.

[0033] Beneficial effects

[0034] The bidirectional sealing performance testing device provided by this invention has the following advantages compared with the prior art:

[0035] (1) The dynamic differential pressure simulation test of the breathing valve assembly was realized: Through the continuous adjustment of two independent adjustable pressure reducing valves, the present invention can simulate the complete gradual process of the differential pressure gradually increasing from zero to the threshold, and truly reproduce the dynamic process of the breathing valve bearing the continuous change of air pressure in actual working conditions. The test results are closer to the actual use situation.

[0036] (2) Solved the problem of synchronous control of air pressure on both sides: Through the integrated dual-chamber structure design of the box and the bracket and the dual-circuit independent control system, the present invention can independently control the pressure chambers on both sides of the breathing valve, simulate the complex working condition of simultaneous change of air pressure on both sides, and break through the limitation of the existing technology that can only test one side.

[0037] (3) Accurate capture of the moment the breathing valve opens: This invention combines the visual indication function of the venting indicator valve with the real-time monitoring of the pressure gauge, so that the operator can obtain a clear signal at the moment the breathing valve opens and accurately record the pressure difference value at the moment of opening, thus solving the measurement error problem caused by the pressure gauge response delay.

[0038] (4) Compact structure and reliable sealing: The present invention adopts the structure of "box + bracket", which realizes two independent pressure chambers with one box, and completely simulates the installation state of the breathing valve on the actual equipment; the multi-level static sealing design ensures the airtightness of the entire device, can withstand bidirectional pressure difference, and can still maintain the seal after multiple disassembly and assembly.

[0039] (5) Easy to operate and good repeatability: This invention decomposes the bidirectional test into independent exhalation test and inhalation test, and with standardized operating procedures, it greatly reduces the difficulty of operation and improves the accuracy and repeatability of the test. It is suitable for rapid verification in the product development process and quality control in mass production.

[0040] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0042] Figure 1 This is a front view of the structure of the present invention;

[0043] Figure 2 for Figure 1 AA section view;

[0044] Figure 3 for Figure 1 Rear view;

[0045] Figure 4 This is a schematic diagram of the external shape of the housing features of the present invention;

[0046] Figure 5 This is a schematic diagram of a preferred embodiment of the present invention. Detailed Implementation

[0047] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0050] The bidirectional sealing performance testing device consists of the following components:

[0051] like Figures 1-5 As shown, the test device for bidirectional sealing test of the present invention mainly includes: a box body (1), a cover plate (2), an inflation valve bracket (3), a first one-way inflation valve (4-1), a second one-way inflation valve (4-2), a connecting screw (5), a first venting indicator valve (6-1), a second venting indicator valve (6-2), a breather valve screw (7), a sealing rubber strip (8), a breather valve assembly (9), an air source (10-1, 10-2), an adjustable pressure reducing valve (11-1, 11-2), and a hose (12-1, 12-2).

[0052] like Figure 4 As shown, the housing (1) is integrally formed from aluminum alloy, with a closed bottom and an open top. The open end face has a threaded hole (1-1) and a sealing groove (1-2). The threaded hole (1-1) is used to connect and fix the cover plate (2) with connecting screws (5). A sealing rubber strip (8) is installed in the sealing groove (1-2) to achieve a static seal between the cover plate (2) and the housing (1). The cover plate (2) has corresponding connecting holes to the housing (1), which are fixed by connecting screws (5).

[0053] The housing (1) forms a first pressure chamber inside, which is used to simulate the sealed inner cavity of the photoelectric pod. One side of the housing (1) is provided with a mounting hole (1-3) for installing a first one-way inflation valve (4-1), and the other side is provided with a mounting hole (1-7) for installing a first vent indicator valve (6-1). The other side of the housing (1) is provided with a through hole (1-5), and a threaded hole (1-4) and a sealing groove (1-6) are provided on its end face to realize the installation, fixation and sealing of the inflation valve bracket (3) on the housing (1).

[0054] The inflation valve bracket (3) is provided with a connection hole corresponding to the housing (1), a mounting hole for installing the second one-way inflation valve (4-2), and a mounting hole for installing the second vent indicator valve (6-2). The inflation valve bracket (3) is fixed to the end face of the housing (1) by connecting screws (5), and a sealing rubber strip (8) is installed between the two to achieve a sealed connection. After the inflation valve bracket (3) is installed, a sealed space is formed between it and the outer wall of the housing (1), namely the second pressure chamber, which is used to simulate the external environment of the breathing valve assembly (9).

[0055] The breather valve assembly (9) is connected and fixed to the side wall of the housing (1) by the breather valve screw (7). The breather valve assembly (9) has a built-in rubber gasket, which is tightened by the breather valve screw (7) during installation to form a reliable end face seal. After installation, the breather valve assembly (9) is connected to the first pressure chamber (inside the housing) on ​​one side and to the second pressure chamber (the space between the bracket and the outer wall of the housing) on ​​the other side, completely simulating the installation state of the breather valve on the actual equipment.

[0056] The first one-way inflation valve (4-1) is threadedly sealed and installed on the housing (1), communicating with the first pressure chamber. The first one-way inflation valve (4-1) is connected to the first adjustable pressure reducing valve (11-1) via a hose (12-1), which is installed and connected to the high-pressure air source (10-1). The first adjustable pressure reducing valve (11-1) is a manual knob-type precision pressure reducing valve, equipped with a pressure gauge. The output air pressure can be continuously adjusted by rotating the knob, and the current pressure value is displayed in real time.

[0057] The second one-way inflation valve (4-2) is threadedly sealed and mounted on the inflation valve bracket (3), communicating with the second pressure chamber. The second one-way inflation valve (4-2) is connected to the second adjustable pressure reducing valve (11-2) via a hose (12-2), which is connected to the high-pressure air source (10-2). The second adjustable pressure reducing valve (11-2) is also a manual knob-type precision pressure reducing valve, which can continuously adjust the air pressure in the second pressure chamber.

[0058] The first vent indicator valve (6-1) is sealed and installed on the housing (1) and communicates with the first pressure chamber. The second vent indicator valve (6-2) is sealed and installed on the inflation valve bracket (3) and communicates with the second pressure chamber. Both vent indicator valves are one-way valves. When the air pressure in the chamber reaches its preset opening pressure, they automatically open to release air and provide a visual indication signal (gas is ejected from the valve port, and airflow disturbance can be seen; if a hose is connected to the valve port and inserted into water, bubbles can be seen). In this embodiment, the opening pressure of the second vent indicator valve (6-2) is set to be the same as the exhalation threshold of the breathing valve assembly (9) (10 kPa), and the opening pressure of the first vent indicator valve (6-1) is set to be the same as the inhalation threshold of the breathing valve assembly (9) (20 kPa).

[0059] in accordance with Figure 5 Complete the assembly of the test apparatus following these steps:

[0060] Install the sealing rubber strip (8) in the sealing groove (1-2) of the housing (1), place the cover plate (2) at the open end of the housing (1), and fix the cover plate (2) to the housing (1) with the connecting screw (5) to achieve the sealing of the first pressure chamber. Install the first one-way inflation valve (4-1) and the first vent indicator valve (6-1) into the corresponding mounting holes of the housing (1) through threaded sealing. Install the sealing rubber strip (8) in the sealing groove (1-6) on the end face of the housing (1), align the inflation valve bracket (3) with the end face of the housing (1), and fix it with the connecting screw (5) to achieve the sealing of the second pressure chamber. Install the second one-way inflation valve (4-2) and the second vent indicator valve (6-2) into the corresponding mounting holes of the inflation valve bracket (3) through threaded sealing. Install the breathing valve assembly (9) onto the mounting interface on the side wall of the housing (1), and tighten it with the breathing valve screw (7) to ensure that its built-in rubber pad fits tightly against the housing. Connect the first one-way inflation valve (4-1) and the first adjustable pressure reducing valve (11-1) with a hose (12-1), and connect the first adjustable pressure reducing valve (11-1) to the high-pressure air source (10-1). Connect the second one-way inflation valve (4-2) and the second adjustable pressure reducing valve (11-2) with a hose (12-2), and connect the second adjustable pressure reducing valve (11-2) to the high-pressure air source (10-2).

[0061] After assembly, the entire test device is designed to be airtight, and all connections are sealed statically with sealing rubber strips or threaded seals.

[0062] according to Figure 5 After the experimental setup is assembled and connected, the expiratory function of the breathing valve assembly (9) is tested. In this embodiment, the expiratory threshold of the breathing valve assembly (9) is preset to 10 kPa, and the inspiratory threshold is preset to 20 kPa.

[0063] Preparation before testing:

[0064] Ensure that the first adjustable pressure reducing valve (11-1) and the second adjustable pressure reducing valve (11-2) are both closed. The readings of the two pressure gauges should be 0 (gauge pressure), indicating that both chambers are under normal pressure. Ensure that the gas source (10-1, 10-2) is open and within the normal working pressure range. Block the first vent indicator valve (6-1) to prevent it from venting during the test.

[0065] Test steps:

[0066] The first step is to confirm that the second adjustable pressure reducing valve (11-2) is in the closed state, so that the second pressure chamber is kept at normal pressure to simulate the external atmospheric environment.

[0067] The second step is to slowly rotate the knob of the first adjustable pressure reducing valve (11-1) to begin filling the first pressure chamber (inside the housing) with air. During the operation, the pressurization rate should be kept uniform and slow. In this embodiment, the pressurization rate is controlled at approximately 0.5 kPa / second to simulate the gradual change in air pressure.

[0068] Third, continuously observe the readings of the pressure gauges on the first adjustable pressure reducing valve (11-1) and the second adjustable pressure reducing valve (11-2), while closely monitoring the second venting indicator valve (6-2). As the air pressure in the first pressure chamber increases, the reading of the pressure gauge on the first adjustable pressure reducing valve (11-1) gradually increases, and the pressure difference between the first and second pressure chambers (i.e., the reading of the pressure gauge on the first adjustable pressure reducing valve (11-1) minus the reading of the pressure gauge on the second adjustable pressure reducing valve (11-2)) also gradually increases.

[0069] Fourth, when the pressure difference reaches 10 kPa, the exhalation channel of the breathing valve assembly (9) should automatically open, and gas should enter the second pressure chamber from the first pressure chamber through the breathing valve. Since the opening pressure of the second venting indicator valve (6-2) is set to 10 kPa, when the gas pressure in the second pressure chamber reaches 10 kPa, the second venting indicator valve (6-2) will automatically open to release gas, and the operator can observe obvious gas discharge.

[0070] Fifth, at the instant the second venting indicator valve (6-2) releases gas, immediately record the readings of the pressure gauges on the first adjustable pressure reducing valve (11-1) and the second adjustable pressure reducing valve (11-2). In this embodiment, if the test is normal, the reading of the pressure gauge on the first adjustable pressure reducing valve (11-1) should be around 10 kPa, and the reading of the pressure gauge on the second adjustable pressure reducing valve (11-2) should be 0 kPa (because gas is released after the venting valve is opened, the second pressure chamber cannot build up pressure), with a pressure difference of 10 kPa, consistent with the preset exhalation threshold.

[0071] Step 6: If the pressure continues to increase after the pressure difference reaches 10 kPa, and the second vent indicator valve (6-2) continues to vent, it indicates that the breathing valve assembly (9) has a normal exhalation function; if the second vent indicator valve (6-2) still does not vent after the pressure difference exceeds 10 kPa, it indicates that the breathing valve assembly (9) has an abnormal exhalation function or the sealing does not meet the requirements.

[0072] After completing the expiratory function test, the inspiratory function test of the breathing valve assembly (9) is performed.

[0073] Preparation before testing:

[0074] Ensure that both the first adjustable pressure reducing valve (11-1) and the second adjustable pressure reducing valve (11-2) are closed; open the pressure relief ports of the first venting indicator valve (6-1) and the second venting indicator valve (6-2) to allow both the first and second pressure chambers to communicate with the atmosphere. After the pressure in both chambers is balanced with the external atmospheric pressure, close the pressure relief ports; confirm that the readings of the pressure gauges on the first adjustable pressure reducing valve (11-1) and the second adjustable pressure reducing valve (11-2) are both 0 (gauge pressure), indicating that both chambers are under normal pressure; block the second venting indicator valve (6-2) to prevent it from venting during the test.

[0075] Test steps:

[0076] The first step is to confirm that the first adjustable pressure reducing valve (11-1) is in the closed state, so that the first pressure chamber is kept at normal pressure, simulating the initial state of the equipment cavity.

[0077] The second step is to slowly rotate the knob of the second adjustable pressure reducing valve (11-2) to begin inflating the second pressure chamber (outside the breathing valve). Similarly, control the pressurization rate to approximately 0.5 kPa / second to simulate the gradual change in air pressure.

[0078] Third, continuously observe the readings of the pressure gauges on the second adjustable pressure reducing valve (11-2) and the first adjustable pressure reducing valve (11-1), while closely monitoring the first venting indicator valve (6-1). As the air pressure in the second pressure chamber increases, the reading of the pressure gauge on the second adjustable pressure reducing valve (11-2) gradually increases, and the pressure difference between the second and first pressure chambers (i.e., the reading of the pressure gauge on the second adjustable pressure reducing valve (11-2) minus the reading of the pressure gauge on the first adjustable pressure reducing valve (11-1)) also gradually increases.

[0079] Fourth, when the pressure difference reaches 20 kPa, the inhalation channel of the breathing valve assembly (9) should automatically open, and gas should enter the first pressure chamber from the second pressure chamber through the breathing valve. Since the opening pressure of the first venting indicator valve (6-1) is set to 20 kPa, when the gas pressure in the first pressure chamber reaches 20 kPa, the first venting indicator valve (6-1) will automatically open to release gas, and the operator can observe obvious gas discharge.

[0080] Fifth, the instant the first venting indicator valve (6-1) releases gas, immediately record the readings of the pressure gauges on the second adjustable pressure reducing valve (11-2) and the first adjustable pressure reducing valve (11-1). In this embodiment, if the test is normal, the pressure gauge reading on the second adjustable pressure reducing valve (11-2) should be around 20 kPa, and the pressure gauge reading on the first adjustable pressure reducing valve (11-1) should be 0 kPa (because gas is released after the venting valve is opened, the first pressure chamber cannot build up pressure), with a pressure difference of 20 kPa, consistent with the preset intake threshold.

[0081] Step 6: If the pressure continues to increase after the pressure difference reaches 20 kPa, and the first vent indicator valve (6-1) continues to vent, it indicates that the breathing valve assembly (9) has a normal inhalation function; if the first vent indicator valve (6-1) still does not vent after the pressure difference exceeds 20 kPa, it indicates that the breathing valve assembly (9) has an abnormal inhalation function or the sealing does not meet the requirements.

[0082] The core of this invention lies in its ability to simulate the dynamic pressure difference changes experienced by a breather valve under actual working conditions. This capability is based on the following technical principles:

[0083] Simulate a continuous gradual change process:

[0084] In actual flight, the change in aircraft altitude is a continuous process, and the air pressure changes continuously and slowly accordingly. This invention employs a manually operated rotary precision pressure reducing valve. Through the linear relationship between the knob's rotation angle and the output pressure, the operator can precisely control the rate of air pressure change. For example, controlling the pressurization rate to 0.5 kPa / second can simulate the gradual increase in pressure differential during aircraft climb. This continuous adjustment capability allows the testing process to realistically reproduce the gradual change in air pressure, avoiding the drawbacks of traditional step-by-step pressurization.

[0085] Independent control of air pressure on both sides:

[0086] By employing two independent pressure regulation loops, this invention enables separate control of the pressure in the first and second pressure chambers. During exhalation testing, the second pressure chamber is maintained at ambient pressure (simulating atmospheric conditions) while the pressure in the first pressure chamber is continuously increased. Similarly, during inhalation testing, the first pressure chamber is maintained at ambient pressure while the pressure in the second pressure chamber is continuously increased. This independent control capability simulates the dynamic changes in pressure across both chambers.

[0087] Precisely determine the moment the breathing valve opens:

[0088] The opening of a breathing valve is a continuous dynamic process involving valve disc displacement, pressure changes, and flow rate changes. Its opening pressure needs to be captured in real time during this continuous pressure differential change. This invention provides a visual signal through a venting indicator valve: when the breathing valve opens, gas flows into the other chamber, causing the pressure in that chamber to rise to the preset value of the venting valve, at which point the venting valve automatically releases gas. The operator observes the venting signal and immediately takes a reading, thus achieving synchronization between the "opening moment" and the "reading moment," solving the problems of pressure gauge response delay and the inability of static readings to capture dynamic processes.

[0089] This embodiment details the structure, assembly method, testing operation process, and technical principle of the test device of the present invention. Through an integrated dual-chamber structure, a dual-circuit independent air pressure regulation system, the continuous adjustment function of the adjustable pressure reducing valve, and the visual indication function of the venting indicator valve, the present invention achieves bidirectional sealing performance testing of the breathing valve assembly under dynamic differential pressure conditions. It can accurately capture the differential pressure value at the moment the breathing valve opens, truly reflecting the response characteristics of the breathing valve in actual use.

[0090] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A test apparatus for bidirectional sealing performance testing, characterized in that, include: The housing (1) has a first pressure chamber inside it; A cover plate (2) is installed in a sealed manner at the opening end of the housing (1); An inflation valve bracket (3) is sealed and installed on the outer wall of the box (1), forming a second pressure chamber between the bracket and the outer wall of the box (1); A breathing valve mounting interface is provided on the housing (1) for sealing and mounting the breathing valve assembly (9) under test, so that the two sides of the breathing valve assembly (9) under test are respectively connected to the first pressure chamber and the second pressure chamber; The first air pressure regulating circuit is connected to the first pressure chamber and is used to independently and continuously regulate the air pressure in the first pressure chamber. The second air pressure regulating circuit is connected to the second pressure chamber and is used to independently and continuously regulate the air pressure in the second pressure chamber. The first venting indicator valve (6-1) is connected to the first pressure chamber and is used to automatically open the venting valve when the air pressure in the first pressure chamber reaches a preset value. The second venting indicator valve (6-2) is connected to the second pressure chamber and is used to automatically open the venting valve when the air pressure in the second pressure chamber reaches a preset value. The first pressure regulating circuit and the second pressure regulating circuit can independently and continuously regulate the pressure of the first pressure chamber and the second pressure chamber, so that a dynamic pressure difference is formed between them to simulate the dynamic pressure difference process that the tested breathing valve assembly (9) is subjected to in actual working conditions; the exhaust phenomenon of the first venting indicator valve (6-1) and the second venting indicator valve (6-2) are used to indicate the opening time of the inhalation function and the exhalation function of the tested breathing valve assembly (9), respectively.

2. The test apparatus for bidirectional sealing testing according to claim 1, characterized in that, The housing (1) is integrally formed from aluminum alloy, with a closed bottom and an open top. The open end face is provided with a sealing groove (1-2) and a threaded hole (1-1). The side is provided with an installation interface for installing the first air pressure regulating circuit interface, the first air release indicator valve (6-1) and the air filling valve bracket (3).

3. The test apparatus for bidirectional sealing testing according to claim 1, characterized in that, The inflation valve bracket (3) is provided with a connection hole corresponding to the box body (1), a hole for installing the second air pressure regulating circuit interface, and a hole for installing the second air release indicator valve (6-2), and is sealed to the box body (1) through a sealing rubber strip (8).

4. The test apparatus for bidirectional sealing testing according to claim 1, characterized in that, The first air pressure regulating circuit includes a first one-way inflation valve (4-1) and a first adjustable pressure reducing valve (11-1). The first one-way inflation valve (4-1) is sealed and installed on the housing (1) and communicates with the first pressure chamber. The first adjustable pressure reducing valve (11-1) is installed on the high-pressure gas cylinder (10-1) and connected to the first one-way inflation valve (4-1) through a hose (12-1). The second air pressure regulating circuit includes a second one-way inflation valve (4-2) and a second adjustable pressure reducing valve (11-2). The second one-way inflation valve (4-2) is sealed and installed on the inflation valve bracket (3) and communicates with the second pressure chamber. The second adjustable pressure reducing valve (11-2) is installed on the high-pressure gas cylinder (10-2) and connected to the second one-way inflation valve (4-2) through a hose (12-2).

5. The test apparatus for bidirectional sealing testing according to claim 4, characterized in that, Both the first adjustable pressure reducing valve (11-1) and the second adjustable pressure reducing valve (11-2) are manual knob-type precision pressure reducing valves, each equipped with a pressure gauge to display the air pressure value of its chamber in real time.

6. The test apparatus for bidirectional sealing testing according to claim 1, characterized in that, The opening pressure of the first vent indicator valve (6-1) is preset to be equal to the inhalation threshold of the tested breathing valve assembly (9), and the opening pressure of the second vent indicator valve (6-2) is preset to be equal to the exhalation threshold of the tested breathing valve assembly (9).

7. The test apparatus for bidirectional sealing testing according to claim 1, characterized in that, The cover plate (2) and the box body (1) and the inflation valve bracket (3) and the box body (1) are both statically sealed by installing sealing rubber strips (8) in the sealing groove; the breathing valve assembly (9) is sealed to the box body (1) by pressing its own rubber pad with the breathing valve screw (7).

8. A method for conducting a bidirectional sealing test using the test apparatus according to any one of claims 1 to 7, characterized in that... Includes the following steps: Expiratory function test: Keep the second pressure chamber at normal pressure, and continuously and slowly increase the pressure to the first pressure chamber through the first pressure regulation circuit, so that the pressure difference between the first pressure chamber and the second pressure chamber gradually increases from zero. At the same time, observe the second venting indicator valve (6-2). When the second venting indicator valve (6-2) is observed to release air, record the pressure difference between the first pressure chamber and the second pressure chamber at this time, which is the expiratory opening threshold of the tested breathing valve assembly (9). Inspiratory function test: Keep the first pressure chamber at normal pressure, and continuously and slowly increase the pressure to the second pressure chamber through the second pressure regulation circuit, so that the pressure difference between the second pressure chamber and the first pressure chamber gradually increases from zero. At the same time, observe the first vent indicator valve (6-1). When the first vent indicator valve (6-1) is observed to vent, record the pressure difference between the second pressure chamber and the first pressure chamber at this time, which is the inspiratory opening threshold of the tested breathing valve assembly (9).

9. The method according to claim 8, characterized in that, Before conducting the expiratory function test, block the first vent indicator valve (6-1); before conducting the inspiratory function test, block the second vent indicator valve (6-2).

10. The method according to claim 8, characterized in that, The rate of continuous and slow pressurization is controlled below 0.5 kPa / second to simulate the gradual change of air pressure. Before the test begins, the pressure in both chambers is released to balance with the external atmospheric pressure by opening the pressure relief port of the vent indicator valve, ensuring that the initial pressure in both chambers is normal.

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