LFY-711A Respiratory Resistance Tester

Main purpose/Use 
The LFY-711A is used to measure the inhalation resistance and exhalation resistance of full-face and half-face protective equipment under specified conditions. It is applicable to national labor protection equipment inspection institutions and mask manufacturers for conducting relevant tests and inspections on full-face and half-face masks. 
Technical indicators 
1. The instrument is composed of an air source with adjustable flow rate, a standard human head model, two sets of pipelines for inhalation and exhalation, and a respiratory resistance measurement system, etc. 
2. The flow sensor has high sensitivity and a very low starting flow rate. 
3. The flow sensor chip uses a thermal mass flowmeter, which eliminates the need for temperature and pressure compensation, ensuring the high accuracy of the sensor's measurement. The flow measurement range is -200 L/min to 200 L/min, with an accuracy of ±2%. 
※4. Multiple sensors are integrated onto a single flow sensor chip, significantly increasing the measurement range of the sensor. 
5. The zero point stability of the flow sensor is high. It features high stability across the entire range, high accuracy, and excellent repeatability. It also has the characteristics of low power consumption, low loss, and fast response speed. 
6. The data recorder uses a 128×64 pixel graphic dot matrix liquid crystal display with a fully Chinese interface, making the operation very convenient. 
7. The data recorder has 4M of internal memory for storing measurement values. 
8. The micro-pressure gauge adopts two-wire communication, featuring high accuracy, good stability, and a reliable explosion-proof design, ensuring safe operation. 
※9. The range and zero point of the micro-pressure sensor can be adjusted continuously externally. The damping can also be adjusted. There is no mechanical moving part, resulting in less maintenance workload. The range of the micro-pressure sensor is -1000Pa to 1000Pa, with an accuracy of 1Pa. 
※10. The entire instrument is equipped with special gas path conversion components, ensuring that the two separate gas path systems for exhalation and inhalation can be switched quickly and smoothly. 
11. The pumping capacity of the vacuum pump should be no less than 30L/min to 160L/min. 
12. Expiratory flow rate: 0 - 160 liters per minute. 
13. The head model can be adjusted in five directions. 
14. Power Supply: AC 220V, 50Hz. 
Applicable Standards 
BS EN 136-1998 Respiratory protective devices-Full face masks-Requirements, testing, marking

EN 149-2001+A1-2009 Respiratory protective devices-Filtering half masks to protect against particles-Requirements, testing, marking