As medical workers, medical masks are our indispensable two-way protective equipment. Before the medical operation, you must wear a medical mask, and some even require that you wear a medical mask during the round. The protective effect of medical masks is directly related to the choice of medical masks, whether to wear medical masks correctly, and the fit of the mask to the face.
Medical masks belong to the second category of medical devices, most of which are self-priming filter masks. Its working principle is to filter the air containing harmful substances through the filter material of the medical mask before being inhaled or exhaled by people.
Working principle of medical mask filter material
1. Diffusion deposition: Brownian motion of particles diffuses to the filter fiber, and is absorbed by the attraction of molecules. It is the easiest to capture small-scale particles, fine fibers and particles moving at low speed.
2. Retentive deposition: The larger particles moving with the air flow are retained by the mechanical screening effect of the filter material. The ratio of particle diameter to membrane fiber diameter affects the interception efficiency.
3. Inertial deposition: When the particles pass through the curved mesh channel of the filter material, the particles are separated from the airflow by the inertial effect and hit the filter fiber, and are trapped by the molecular gravity. The large particles, high density, and fast speed have good interception effect.
4. Electrostatic attraction deposition: the deposition of particles generated by the electrostatic action of the filter fiber.
The smaller the particles, the stronger the deposition effect of 1, 4; the larger the particles, the better the effect of 2, 3, so the smaller the particles, the more difficult to filter. Synthesizing the synergistic effect of various filtration mechanisms, the range of the most easily penetrated particle size of ordinary mechanical filter materials is 0.1m ~ 0.3m.
Product structure
Medical masks are generally composed of the following materials:
Main filter material: such as polypropylene meltblown cloth, etc. Other materials: metal (for nose clips), stains, elastic materials (for mask bands), etc.
Medical masks generally have the following forms:
According to the shape of the mask, it can be divided into plane, duckbill, arch or folding. According to the way of wearing, it can be divided into earhook type, strap type or headband type.
Post time: Apr-29-2020