The principle of the operation of medical masks

The principle of the operation of medical masks


    Medical masks belong to the second category of medical devices, most of which are self-priming filter masks. The working principle is that the air containing harmful substances is filtered through the filter material of the medical mask and then inhaled or exhaled.

 

The working principle of medical mask filter:

 

1. Diffusion deposition: The particle Brownian motion is diffused and displaced to the filter fiber, and is adsorbed by molecular gravitation. *** Easy to capture small-scale particles, fine fibers, and low-speed moving particles.

 

2. Interception sedimentation: Larger particles moving with the gas stream are trapped by a mechanical screening of the filter material. The ratio of the particle diameter to the diameter of the filter fiber affects the intercept efficiency.

 

3. Inertial deposition: When the particles pass through the mesh channel curved by the filter material, the particles break away from the airflow and impinge on the filter fiber due to inertia, and are trapped by molecular gravitation. Large particles, high density, and fast interception effect.

 

4. Electrostatic attraction deposition: the deposition of particles by the electrostatic action of the filter fibers.

 

The smaller the particles, the stronger the deposition effect of 1, 4, and the larger the particles, the better the effect of 2, 3, so the smaller the particles, the harder it is to be filtered. Synergistic effect of the comprehensive seed filtration mechanism, the range of easy penetration diameter of ordinary mechanical filter material is 0.1m ~ 0.3m.