Scope of Application

【Operating Instructions】

Simple operation and easy connection; one-button operation after connecting the test specimen, improving test efficiency. Adopts a negative pressure biosafety cabinet test system, equipped with an exhaust fan system and inlet/outlet air filters to ensure operator safety. The biosafety cabinet features a liftable glass door for convenient observation. The operating system uses an industrial-grade PLC for accurate data processing, supporting flexible parameter settings and test data storage.

**YS-0469A Medical Surgical Mask Bacterial Filtration Efficiency (BFE) Tester**

**【Instrument Features】**  

1. Fully complies with the test requirements of Appendix B in YY 0469-2011.  

2. Simple operation and easy connection; one-button operation after connecting the test specimen, improving test efficiency.  

3. Adopts a negative pressure biosafety cabinet test system, equipped with an exhaust fan system and inlet/outlet air filters to ensure operator safety. The biosafety cabinet features a liftable glass door for convenient observation.  

4. The operating system uses an industrial-grade PLC for accurate data processing, supporting flexible parameter settings and test data storage.  

5. The control terminal features a high-brightness color touch screen with a user-friendly and intuitive interface.  

6. All core components are imported from well-known international brands, ensuring high detection accuracy and repeatability.  

7. Equipped with comprehensive protection functions: automatically activates protection when test data exceeds limits, preventing damage due to misoperation and reducing operational difficulty for testing personnel.  

8. Equipped with a microcomputer-controlled automatic start/stop pressure source, simple to operate; the pressure source includes a buffer tank for more stable output pressure.

**【Technical Parameters】**  

1. Positive pressure source and air filtration system: adjustable output pressure from 5 to 500 kPa.  

2. Negative pressure source and filtration system: provides negative pressure air source of no less than 60 L/min.  

3. Dedicated aerosol generator: provides aerosol with particle size and concentration meeting test requirements.  

4. Precision flow control: range 0–30 L.  

5. Equipped with a dedicated sampler for holding the test specimen.  

6. LCD touch screen display and operation.  

7. PLC control.  

8. Power supply: 220 V / 50 Hz.  

9. Test time range: 0–3600 s (adjustable).

**【Pneumatic Schematic Diagram】**  

1. The test system mainly consists of an aerosol generator, an aerosol chamber, a sampler, and a vacuum air source.  

   1.1 The core components of the aerosol generator are an imported aerosol generator from the UK and an imported pressure control unit from Japan. The pressure control unit regulates the gas pressure applied to the aerosol generator to produce aerosol with appropriate concentration and particle size. Gas pressure is controlled to within 0.1 kPa and can be adjusted in real time during the test.  

   1.2 The dosing device of the aerosol generator: a peristaltic pump was considered, but it delivers discontinuous flow at 0.01 mL/min. Therefore, an aerosol generator with a liquid reservoir is selected, allowing the test solution to be added directly to the generator, with adjustment via the spray nozzle.  

   1.3 The positive pressure air source is provided by an oil-free air compressor, filtered through an air filter, and then connected to the pressure control unit, with adjustable pressure from 5 to 500 kPa.  

2. The aerosol chamber is constructed as shown in Figure B.2, with two sampler ports and reserved filter ports.  

3. Two Andersen samplers are used. Flow rate is controlled by adjustable flow switches at the rear of the samplers, with a range of 0–50 L. Gas drying is required between the samplers and the flow meters.  

4. The vacuum source is provided by two vacuum pumps, each capable of supplying a negative pressure airflow of no less than 30 L/min.

**【Program Functions】**  

1. Open configuration of all experimental steps: All steps in the experiment are configured along a unified time axis, including parameters such as generator operation time and sampler operation time, with full access to start and stop times. Experimental procedures can be flexibly and intuitively customized.  

2. Negative pressure intake protection: Real-time monitoring of positive intake pressure ensures that the gas demand of the aerosol generator is met during the test, ensuring the production of qualified aerosol; otherwise, an alarm is triggered and the test stops.  

3. Negative pressure source protection: Real-time monitoring of negative pressure and flow during the test ensures compliance with standard test conditions; otherwise, an alarm is triggered and the test stops.  

4. Automatic positive gas pressure control: Simply input the required pressure for the generator, and the internal system algorithm automatically adjusts and stabilizes the pressure to the required value.

**【Test Procedure】**  

1. Turn on the air compressor and vacuum pump power and valves to start air supply.  

2. Connect all components and tubing.  

3. Connect the Andersen samplers.  

4. Add the test bacterial suspension to the nebulizer.  

5. Set test parameters on the parameter setting interface according to the test time requirements in standard B.4.  

6. Perform positive control, sample challenge, and negative control experiments in sequence according to the test steps in B.4.  

7. Culture the agar plates.  

8. Clean the inside of the equipment and the tubing for the next test.