Principles of protective masks

Protective mask is a kind of respiratory protective equipment for the purpose of preventing the transmission of certain respiratory infectious microorganisms and protecting the health of the body. What is the protective principle of the protective mask? Materials for filtering particles include mineral fibres, natural fibres, or synthetic fibres. There are five mechanisms that comprehensively filter airborne particles.

Settling function: large particles are affected by the gravity in the airflow, settle the filter material and separate from the airflow; inertial impact: when the particles in the airflow bypass the filter fibers blocked before the airflow, the high-quality particles affected by inertia will deviate from the airflow direction, impact the filter fiber and filter it out; interception function: because the particle radius is greater than the distance between the streamline and the filter material, the particles in the airflow are closest to the distance between the streamline and the filter material "scratch" interception; diffusion: affected by Influenced by the thermal movement of air molecules, small particles are affected by air molecules, constantly changing the direction of motion, showing Brownian motion, and randomly contacting the filter fibers; electrostatic effect: if the static electricity of the filter fibers is weak, when they are close to the filter fibers, no matter in the airflow Whether the particles have static electricity, they are easily attracted and filtered out by static electricity. The electrostatic effect helps to increase the filtration efficiency of the filter material without increasing the airflow resistance.