Mask total leakage rate detector

Abstract

The utility model belongs to the technical field of detection equipment, and particularly relates to a mask total leakage rate detector which comprises a box body, a combustion chamber used for combusting sodium chloride aerosol particles is arranged in the box body, a light dimmer is installed on a light source passage of the combustion chamber, and a photomultiplier is installed on the light dimmer. Quantitative analysis on the concentration of the aerosol particles is realized by detecting characteristic yellow light generated by combustion of the sodium chloride aerosol particles; the gas inlet end of the combustion chamber is connected with a hydrogen inlet joint, the gas outlet end is connected with a vacuum generator, and the hydrogen inlet joint is connected with a mass flow meter to ensure that hydrogen enters the combustion chamber at stable flow; the gas collection pipeline mechanism comprises a mask gas path, a cabin gas path and a clean air path, and switching of the different gas paths is achieved through a five-way valve; compressed air inlet is divided into two paths, one path is discharged after passing through the vacuum generator, and the other path provides dry airflow; and accurate control over airflow is achieved through the first three-way valve, the pressure reducing valve and the second gas flow meter.

Description

Technical Field

[0001] The utility model belongs to the technical field of detection equipment, and particularly relates to a total leakage rate detector for masks. Background Technique

[0002] As an individual respiratory protection equipment, the protective mask plays a crucial role in public health events and industrial protection. The mask can cover the mouth and nose of a person, and through the power provided by the inhalation process, environmental particulate matter enters the breathing area after being filtered by the mask material, which can be used to block pathogenic microorganism particles transmitted through the air. The total leakage rate of the mask is directly related to the safety of the user and is one of the key indicators for evaluating the overall protection performance of the mask. The total leakage rate is a key performance specified in the standards of many individual protection products such as protective masks, respirators, and protective clothing. The total leakage rate of the mask refers to the ratio of the concentration of the simulant leaking into the mask from all parts including the mask material to the concentration of the simulant in the inhaled air under the specified test conditions in the laboratory. Usually, sodium chloride aerosol particles are used as the simulant.

[0003] The mandatory national standard for civilian masks in China, GB 2626-2019, and the mandatory national standard for medical protective masks, GB

[0004] 19083-2023 both require the detection of the total leakage rate. The new version of the standard, GB 19083-2023, was released on November 27, 2023, and will be implemented on December 1, 2025. The standard stipulates that medical protective masks should be detected according to the method specified in the medical device industry standard YY / T 0866 "Detection Method for Total Leakage Rate of Medical Protective Masks", and the sodium flame photometer method in the pulsed sampling mode is used as the arbitration method. In addition, the newly released mandatory medical device industry standards, YY 1881-2023 "Medical Positive Pressure Air Supply Respirator" and YY 1887-2023 "Medical Positive Pressure Protective Clothing", also require the detection of the total leakage rate.

[0005] The existing detection of the total leakage rate of individual protective equipment such as masks is mainly carried out through quantitative aerosol particulate matter detection technology. However, the existing detection instruments have problems such as weak specificity, insufficient sensitivity, limited detection range, and complex operation, and cannot comprehensively and accurately reflect the protection performance of masks in the actual use environment. In the detection of the mask leakage rate, the commonly used aerosol particulate matter is sodium chloride aerosol particles. When sodium chloride aerosol particles burn in the air, sodium elements will produce characteristic yellow light (wavelength about 589nm). By detecting the optical signal of this specific wavelength, the concentration of sodium chloride aerosol particles in the air can be quantitatively analyzed. Therefore, how to accurately, quickly, and real-time capture and analyze this optical signal in a complex detection environment and continuous air sampling process has become the key to improving the detection accuracy of the mask leakage rate.

[0006] The existing detection methods have the following deficiencies:

[0007] 1. The detection sensitivity is not high, making it difficult to accurately detect low-concentration and small-particle-size aerosol particles.

[0008] 2. The operation is complex, the detection process is cumbersome, and the efficiency is low.

[0009] 3. The equipment is bulky and not convenient for on-site detection.

[0010] 4. The specificity is not strong, and the results are easily interfered by other aerosol particles. Summary of the Utility Model

[0011] Aiming at the problems existing in the prior art, the purpose of the present utility model is to provide a total leakage rate detector for masks, which can achieve accurate and rapid evaluation of the total leakage rate of individual protective equipment such as protective masks.

[0012] To achieve the above object, the present utility model provides the following technical solutions:

[0013] A total leakage rate detector for masks, the technical key points of which are: including a box body, a combustion chamber is arranged at one end inside the box body for burning sodium chloride aerosol particles, a light attenuator is installed on the light path of the combustion chamber light source, a photomultiplier tube is installed on the light attenuator, and the light emitted when the combustion chamber burns sodium chloride aerosol particles is filtered by the light attenuator and then irradiates the photosensitive area on the photomultiplier tube;

[0014] The intake end of the combustion chamber is connected with a hydrogen intake joint, and the hydrogen intake joint is used to connect the hydrogen required for combustion;

[0015] The outlet end of the combustion chamber is connected with a vacuum generator;

[0016] It also includes a gas collection pipeline mechanism, which includes a mask gas path, a chamber gas path and a clean air gas path. The mask gas path is used to collect the air inside the mask of the test person, and the chamber gas path is used to collect the air inside the test chamber; the clean air gas path is used to transport clean air as a reference for the other two gas paths;

[0017] It also includes a compressed air intake. The air path of the compressed air intake is divided into two paths. One path is discharged after passing through the vacuum generator; the other path provides a dry air flow for diluting and drying the aerosol particles.

[0018] Further, a mass flow meter is connected in series between the hydrogen intake joint and the combustion chamber.

[0019] Further, a pressure sensor pipeline interface is arranged at one end of the box body, and the pressure sensor pipeline interface is used to detect the pressure inside the mask.

[0020] Furthermore, the clean air gas path includes a five-way valve, and an intake pipe is connected between the five-way valve and the intake end of the combustion chamber;

[0021] And a first gas flow meter and an air filter are connected to the top pipeline of the five-way valve;

[0022] When the five-way valve rotates to clean air, the intake pipe, the first gas flow meter and the air filter are connected in communication.

[0023] Furthermore, the output end of the compressed air intake is connected with a compressed air precision filter for separating moisture in the air, and the output end of the compressed air precision filter is connected with a first three-way valve;

[0024] One path on the first three-way valve is connected to the intake end of the vacuum generator.

[0025] Furthermore, the other path of the first three-way valve is connected with the mask gas path, and a pressure reducing valve and a second gas flow meter are successively connected in series between the first three-way valve and the mask gas path.

[0026] Furthermore, the chamber gas path is connected to the five-way valve, and a second three-way valve is arranged between the chamber gas path and the five-way valve.

[0027] Furthermore, a solenoid valve is arranged between the mask gas path and the five-way valve.

[0028] Compared with the prior art, the beneficial effects of the present utility model are:

[0029] By burning sodium chloride aerosol particles in the combustion chamber and detecting the optical signal of a specific wavelength by a photomultiplier tube, the real-time quantitative analysis of the concentration of sodium chloride aerosol particles in the air can be realized. This design overcomes the problems of insufficient specificity and sensitivity of traditional detection methods, and performs excellently especially in the detection of low-concentration aerosol particles. And it can cover all aerosol particles with the whole particle size distribution. In addition, by adjusting the light intensity through a light attenuator, the detection range of the photometer covers 10 ng / m 3 to 15 mg / m 3 , which is applicable to the total leakage rate detection of personal protective equipment such as protective masks with different design types and different levels of filtration efficiency, and is simple to operate without too much human intervention.

[0030] The gas collection pipeline mechanism of the photometer of the present utility model includes a mask air path, a chamber air path, and a clean air path, which realizes the effective collection of aerosol particles in different sampling environments. Through the switching of the five-way valve, the intake end of the combustion chamber can be flexibly connected to the clean air, the air path inside the mask, or the air path inside the chamber to meet different detection requirements. In addition, the dry air flow provided by the dry air path effectively dilutes and dries the aerosol particles, ensuring the accuracy and stability of the sampling process.

[0031] Through the design of the clean compressed air system, the air path of the compressed air intake is divided into two paths. One path is discharged after passing through the vacuum generator; the other path provides a dry air flow for diluting and drying the aerosol particles. The compressed air precision filter ensures the cleanliness of the air, removes the moisture in the air, and guarantees the stability of the combustion and detection environment. Through the first three-way valve, pressure reducing valve, and second gas flowmeter, the precise control of the air flow is realized, further improving the accuracy of the detection.

[0032] In the design of the present utility model, the combination of the combustion chamber structure, hydrogen intake joint, and mass flowmeter ensures that hydrogen enters the combustion chamber at a stable flow rate, mixes with air and is ignited to generate a stable flame as the excitation source of sodium element. This design effectively solves the problem of unstable hydrogen flow rate during the combustion process, ensuring the reliable capture and analysis of optical signals.

[0033] Through the pressure sensor pipeline interface provided at one end of the box body, the pressure change inside the mask can be detected in real time, realizing the accurate identification of the breathing process in the pulse sampling mode. The introduction of the solenoid valve realizes the precise control of the air flow in the mask air path, ensuring the stability and reliability of the detection process.

[0034] Through the above structural design, the photometer of the present utility model provides a device with high specificity, sensitivity, simple operation, and suitable for on-site detection. It overcomes the deficiencies of the prior art and can accurately and quickly evaluate the inward leakage rate of personal protective equipment such as protective masks, providing a reliable technical means for the research and development design, quality control, registration and commission inspection, and supervision and sampling inspection of personal protective equipment such as masks. Brief Description of the Drawings

[0035] Figure 1 is a schematic structural diagram of the present utility model;

[0036] Figure 2 is a top view of the present utility model;

[0037] Figure 3 is a three-dimensional view of the present utility model;

[0038] Figure 4 is a side view of the present utility model.

[0039] In the attached drawings, the list of components represented by each reference numeral is as follows:

[0040] 2. Compressed air precision filter; 3. Air filter; 4. Pressure reducing valve; 5. First three-way valve; 6. Solenoid valve; 7. First gas flowmeter; 9. Second gas flowmeter; 11. Five-way valve; 12. Photomultiplier tube; 13. Vacuum generator; 14. Light attenuator; 16. Combustion chamber; 17. Mass flowmeter; 22. Hydrogen intake joint; 23. Compressed air intake; 26. Mask air path; 27. Chamber air path; 28. Pressure sensor pipeline interface. Detailed implementation mode

[0041] In order to make the purpose and advantages of the present utility model more clear and understandable, the present utility model will be specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific implementation manners of the present utility model, and does not strictly limit the scope of protection specifically requested by the present utility model.

[0042] Embodiment 1

[0043] Refer to Figures 1-4 , a total leakage rate detector for masks, comprising a box body. At one end inside the box body, there is a combustion chamber 16 for burning sodium chloride aerosol particles. A light attenuator 14 is installed on the light source path of the combustion chamber 16, and a photomultiplier tube 12 is installed on the light attenuator 14. The light emitted when the combustion chamber 16 burns sodium chloride aerosol particles is filtered by the light attenuator 14 and then irradiates the photosensitive area on the photomultiplier tube 12. The photomultiplier tube 12 feeds back the current value representing the particle concentration in real time by detecting the current intensity generated by light of a specific wavelength.

[0044] The intake end of the combustion chamber 16 is connected with a hydrogen intake joint 22, and the hydrogen intake joint 22 is used to connect the hydrogen required for combustion. Hydrogen enters the combustion chamber 16 with an accurate flow rate through a mass flowmeter 17, mixes with air and is ignited. The flame serves as the excitation source for sodium elements in the sodium chloride aerosol particles, generating characteristic yellow light (wavelength about 589 nm). The outlet end of the combustion chamber 16 is connected with a vacuum generator 13. The vacuum generator 13 adjusts the discharge air flow rate so that the intake air flow rate of the combustion chamber 16 remains at 2 L / min, and this flow rate is also the aerosol sampling flow rate entering the combustion chamber 16.

[0045] It also includes a gas collection pipeline mechanism, which includes a mask air path 26, a chamber air path 27, and a clean air path; the mask air path 26 is used to collect the air inside the tester's mask, the chamber air path 27 is used to collect the air inside the test chamber, and the clean air path is used to transport clean air as a reference for the other two air paths; the gas collection pipeline mechanism realizes the switching of different air paths through a five-way valve 11; the five-way valve 11 can connect the intake end of the combustion chamber 16 to any one of the three air paths of clean air, inside the mask, or inside the chamber for sampling and detection;

[0046] It also includes a compressed air intake 23. The air path of the compressed air intake 23 is divided into two paths. One path is discharged after passing through a vacuum generator 13; the other path provides a dry air flow for diluting and drying aerosol particles; the output end of the compressed air intake 23 is connected to a compressed air precision filter 2, which is used to separate the moisture in the air. The output end of the compressed air precision filter 2 is connected to a first three-way valve 5; one passage on the first three-way valve 5 is connected to the intake end of the vacuum generator 13, and the other passage is connected to the mask air path 26; a pressure reducing valve 4 and a second gas flowmeter 9 are sequentially connected in series between the first three-way valve 5 and the mask air path 26 to accurately control the air flow rate.

[0047] Refer to Figure 1 , a mass flowmeter 17 is connected in series between the hydrogen intake joint 22 and the combustion chamber 16; the mass flowmeter 17 is used to detect and control the hydrogen flow rate to ensure the stability of the combustion process; Refer to Figure 1 and 4 , one end of the box body is provided with a pressure sensor pipeline interface 28, which is used to detect the pressure inside the mask; through the pressure sensor pipeline interface 28, the air pressure change inside the mask can be monitored in real time to accurately identify the breathing process in the pulse sampling mode.

[0048] Refer to Figure 1 and 4 , the clean air path includes a five-way valve 11. An intake pipe is connected between the five-way valve 11 and the intake end of the combustion chamber 16; a first gas flowmeter 7 and an air filter 3 are connected to the top pipeline of the five-way valve 11; when the five-way valve 11 rotates to clean air, the intake pipe, the first gas flowmeter 7, and the air filter 3 are connected to ensure that the air entering the combustion chamber 16 passes through filtration and flow control to achieve the cleanliness and stable flow rate required for detection.

[0049] Refer to Figures 2-4, the output end of the compressed air inlet 23 is connected to a compressed air precision filter 2, which is used to separate moisture from the air; the output end of the compressed air precision filter 2 is connected to a first three-way valve 5; one passage on the first three-way valve 5 is connected to the inlet end of the vacuum generator 13, and the other passage is connected to the mask air path 26; through the pressure reducing valve 4 and the second gas flowmeter 9, the stability and precise control of the air flow are ensured.

[0050] Refer to Figure 1 and Figure 4 , the chamber air path 27 is connected to the five-way valve 11; through the five-way valve 11, the inlet end of the combustion chamber 16 can be selectively connected to the chamber air path 27 to realize the sampling and detection of the air in the chamber; refer to Figure 1 and Figure 4 , an electromagnetic valve 061 is provided between the mask air path 26 and the five-way valve 11; the electromagnetic valve 061 is used to control the on-off of the air flow, and the precise control of the air flow in the mask air path 26 can be realized through the electromagnetic valve 061 to ensure the stability and reliability of the detection process.

[0051] Through the above structural design, the photometer of the present utility model can accurately detect the concentration of sodium chloride aerosol particles inside and outside the mask, and is applicable to the total leakage rate detection of personal protective equipment such as protective masks, providing a reliable technical means for the research and development design, quality control, registration and commission inspection, and supervision and sampling inspection of personal protective equipment such as masks.

[0052] The working principle of the present utility model is as follows: when sodium chloride aerosol particles in the air burn, sodium elements will produce characteristic yellow light (wavelength about 589nm), and the concentration of sodium chloride aerosol particles inside and outside the mask is quantitatively detected by using a photomultiplier tube 12 to detect the current intensity generated by light of a specific wavelength.

[0053] Through precise flow control, sodium chloride aerosol particles in the air are introduced into the combustion chamber 16, and the light generated by combustion is filtered by the light attenuator 14 and then irradiated onto the photosensitive area of the photomultiplier tube 12, and the current value representing the particle concentration is fed back in real time.

[0054] By adjusting different light attenuation intensities, the detection range of the sodium chloride aerosol particle concentration can cover 10 ng / m 3 ~15 mg / m 3 , and is applicable to the total leakage rate detection of personal protective equipment such as different-level protective masks.

[0055] The present utility model introduces clean compressed air through the compressed air inlet 23, and the compressed air is divided into two paths,

[0056] one path is discharged after passing through the vacuum generator, and the other path provides the dry air flow required for detection (adjusted to 1 L / min).

[0057] The vacuum end of the vacuum generator 13 is connected to the exhaust end of the combustion chamber 16. By adjusting the air flow rate in the air path of the vacuum generator 13, the intake air flow rate of the combustion chamber 16 is made 2 L / min.

[0058] High-purity hydrogen is introduced into the combustion chamber 16 at a certain flow rate through a pressure switch and a mass flow meter 17, mixed with the incoming air and then ignited. The flame serves as the excitation source for the sodium element in the sodium chloride aerosol particles, and the characteristic yellow light is introduced into the light incident window of the photomultiplier tube after passing through the light attenuator assembly. The content of the sodium element is quantified by the magnitude of the output current value. When the light attenuator is in the fully closed state, the ammeter pointer and display are adjusted to zero.

[0059] By adjusting the five-way valve 11, the intake end of the combustion chamber 16 can be connected to any one of the three air paths of clean air, the inside of the mask, or the cabin interior for sampling and detection.

[0060] Another dry air flow provided by the compressed air is used for drying and diluting the aerosol particles in the mask interior or the cabin interior.

[0061] During use, the corresponding light attenuation coefficient of the combined light attenuator 14 is manually or automatically selected according to the specific use scenario. In the pulse sampling mode, the intake end of the combustion chamber 16 is connected to the air path inside the mask. The micro differential pressure sensor is used to detect the pressure change inside the mask to determine whether it is inhalation or exhalation, and the inhalation and exhalation durations are recorded. During exhalation, the air filtered by the high-efficiency filter is collected, and during inhalation, the aerosol particles inside the mask are collected. In the continuous sampling mode, the intake end of the combustion chamber 16 is connected to the air path inside the mask, and the inhalation and exhalation processes are not recognized, and the aerosol particles inside the mask are continuously collected.

[0062] The product of the photocurrent output value and the corresponding light attenuation multiple is the total current value obtained after the aerosol particles burn. By generating sodium chloride aerosol standard particles with different concentrations, the corresponding relationship between the concentration of sodium chloride aerosol particles in the air and the output current value after combustion can be obtained. By calculating the ratio of the concentrations of sodium chloride aerosol particles inside and outside the mask, it is the total leakage rate of the mask.

[0063] Example 2

[0064] In Example 1, the collected values are substituted into the corresponding calculation formulas.

[0065] Pulse sampling calculation formula:

[0066]

[0067] In the formula:

[0068] P(%) —— total leakage rate;

[0069] C0 —— Background concentration of particles inside the mask, unit: mg / m 3 ;

[0070] C1 —— Mass concentration of aerosol particles inside the sealed cabin, unit: mg / m 3 ;

[0071] C2 —— Average mass concentration of particles inside the mask, unit: mg / m 3 ;

[0072] t in —— Total inhalation time, unit: s;

[0073] t ex —— Total exhalation time, unit: s;

[0074] S —— Sampling flow rate in the breathing area, unit: L / min;

[0075] D —— Dry air flow rate, unit: L / min.

[0076] Example 3

[0077] In Example 1, the collected numerical values were substituted into the corresponding calculation formulas.

[0078] Continuous sampling calculation formula:

[0079]

[0080] In the formula:

[0081] P(%) —— Total leakage rate;

[0082] C0 —— Background concentration of particles inside the mask, unit: mg / m3;

[0083] C1 —— Mass concentration of aerosol particles inside the sealed cabin, unit: mg / m3;

[0084] C2 —— Average mass concentration of particles inside the mask, unit: mg / m3;

[0085] S —— Sampling flow rate inside the mask, unit: L / min;

[0086] D —— Dry air flow rate, unit: L / min.

[0087] 1.25 is used as a constant to correct the interception effect of the human lungs on sodium chloride particles during sampling in the breathing area.

[0088] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present utility model. The structures, devices, and operation methods not specifically described and explained in the present utility model, unless otherwise specified and limited, are implemented according to the conventional means in the art.

Claims

1. A mask total leakage rate detector, characterized in that: The invention comprises a box body, a combustion chamber (16) is arranged at one end of the box body, a dimmer (14) is installed on the light source path of the combustion chamber (16), a photomultiplier tube (12) is installed on the dimmer (14), and light emitted by the combustion chamber (16) during combustion is filtered by the dimmer (14) and then irradiated to the photosensitive area on the photomultiplier tube (12); The gas inlet end of the combustion chamber (16) is connected to a hydrogen gas inlet connector (22), and the hydrogen gas inlet connector (22) is used to connect the hydrogen required for combustion; The gas outlet end of the combustion chamber (16) is connected to a vacuum generator (13); It also includes a gas collection pipeline mechanism, which includes a mask air path (26), a cabin air path (27) and a clean air path, wherein the mask air path (26) is used to collect air in the mask of the tester, and the cabin air path (27) is used to collect air in the test chamber; the clean air path is used to transport clean air; It also includes a compressed air intake (23), the air path of the compressed air intake (23) is divided into two paths, one path is discharged after passing through the vacuum generator (13); and the other path provides a dry air flow.

2. A mask total leakage rate detector according to claim 1, characterized in that: A mass flow meter (17) is connected in series between the hydrogen inlet connector (22) and the combustion chamber (16).

3. A mask total leakage rate detector according to claim 1, characterized in that: A pressure sensor pipeline interface (28) is provided at one end of the box body, and the pressure sensor pipeline interface (28) is used to detect the pressure inside the mask.

4. A mask total leakage rate detector according to claim 1, characterized in that: The clean air path comprises a five-way valve (11), and an intake pipe is connected between the five-way valve (11) and the intake end of the combustion chamber (16); A first gas flow meter (7) and an air filter (3) are connected to the top pipeline of the five-way valve (11); When the five-way valve (11) rotates to the clean air state, the air intake pipe, the first gas flow meter (7) and the air filter (3) are connected.

5. A mask total leakage rate detector according to claim 1, characterized in that: The output end of the compressed air inlet (23) is connected to a compressed air precision filter (2), the compressed air precision filter (2) is used to separate moisture from the air, and the output end of the compressed air precision filter (2) is connected to a first three-way valve (5); A passage on the first three-way valve (5) is connected to the air inlet end of the vacuum generator (13).

6. A mask total leakage rate detector according to claim 5, characterized in that: Another passage of the first three-way valve (5) is connected to the mask gas circuit (26), and a pressure reducing valve (4) and a second gas flow meter (9) are sequentially connected in series between the first three-way valve (5) and the mask gas circuit (26).

7. A mask total leakage rate detector according to claim 6, characterized in that: The cabin air path (27) is connected to the five-way valve (11).

8. A mask total leakage rate detector according to claim 7, characterized in that: A solenoid valve (6) is provided between the mask air path (26) and the five-way valve (11).

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