Original Title: Introduction to Types, Scope of Application and Structural Principles of Masks Introduction to types, scope of application and structure principle of respirator I. Overview There are three types of masks managed according to medical devices. According to the protection level of masks, they are medical protective masks, surgical masks and medical masks (disposable medical masks), all of which are managed according to two types of medical devices. Ordinary gauze masks and cotton masks are not managed as medical devices. At present, there are three mask manufacturers in our province, all of which can produce disposable medical masks. 2. What are N95, N90 and KN95 masks? N95, N90 and other masks on the market are medical protective masks, first introduce what is N95, N90, KN95 and other masks. Take N95 as an example, nine kinds of particulate masks certified by the National Institute of Occupational Safety and Health of the United States, N means not suitable for oily particles (for example, cooking fumes are oily particles,KN95 Mask with Fast Shipping, while droplets produced by people speaking or coughing are not oily), 95 refers to the standards of the National Institute of Occupational Safety and Health of the United States. The filtration efficiency of 0.3 micron particles with droplet size reaches 95%. N95 is not a specific product name, as long as it meets the N95 standard and passes the review of the National Institute for Occupational Safety and Health, it can be called N95 mask. By analogy, the N90 is the same way. III. Structure and composition of the mask (I) The composition of the masks managed according to medical devices is basically the same, which is mainly composed of the following materials: main filter materials,Medical Disposable Coverall, such as polypropylene melt-blown cloth, etc. Other materials, such as metal (for nose clip), dye, elastic material (for mask belt), etc. The specific structural composition, action principle and application scope of the three masks are as follows: 1. A protective mask consists of one or more aerosols against viruses. The mask is made of fabrics with isolation effect, such as virus-containing liquid, etc. Protective masks are made of suitable materials with small airflow resistance, synthetic blood barrier, specific strength, 3 Ply Disposable Protective Face Mask ,Medical Full Body Coverall, filtration efficiency, surface moisture resistance and flame retardant performance. They are self-priming and consist of mask body (including nose clip) and mask belt. They can be divided into three levels according to different filtration efficiency. It still has barrier effect on virus aerosol and virus-containing liquid under respiratory airflow, and the outer surface of the mask is not in contact with the human body when it is taken off. Is worn on the face of a person in contact with viral material in a healthcare facility to prevent transmission of the virus from the patient to the medical staff. 2. A surgical mask usually consist of a facemask, , shaped parts, belts and other components, generally made of non-woven fabric materials. It plays a role of isolation through filtration. The surgical mask prevents pathogens, microorganisms, body fluids and particles from being directly filtered and inhaled or exhaled by the human body through the filter material. It is worn on the mouth and nose of the medical staff in the operating room to prevent dander and respiratory tract microorganisms from spreading to the open surgical wound, and to prevent the body fluid of the surgical patient from spreading to the medical staff, so as to play a role of two-way biological protection. Expand the full text 3. The medical mask product consists of a mask and a mask which are connected. 。 The product is sterilized and disposable. Most medical masks are self-inhaling filter masks, whose working principle is to make the air containing harmful substances filtered through the filter material of the mask and then inhaled or exhaled. Is suitable for being worn by clinical medical staff in the process of invasive operation, provides protection for patients receiving treatment and medical staff implementing the invasive operation, and prevents the transmission of blood, body fluid and splashes. Exemptions do not include products with new features such as antivirus. IV. Applicable Scope of Various Masks According to the standards and important technical indicators of all kinds of medical masks: 1. Medical protective masks are suitable for the protection of medical staff and related workers against airborne respiratory infectious diseases. ? High protection grade; 2. Surgical mask basic protection for medical staff or associated personnel , and protection against the spread of blood, body fluids, and splashes during invasive procedures; 3. The protective effect of ordinary disposable medical masks on pathogenicity microorganisms is not exact. ? Can be used for disposable sanitary care in normal environments, or as a barrier or protection against particles other than microorganisms, such as pollen, in pathogenicity. According to the overall evaluation of the protective performance of the mask, the protective mask is superior to the surgical mask, the surgical mask is superior to the ordinary disposable medical mask, and the three-dimensional mask is better than the plane mask. 5. Masks generally have the following forms: According to the shape of the mask, it can be divided into plane, duckbill, arch or folding type. According to the way of wearing, it can be divided into ear hanging type, bandage type or headband type. Flat shape Duckbill (headband) Arched Folding type Ear hanging type Bandage VI. Product standards for three kinds of masks The filtration mechanism of the mask filter material is shown in the schematic diagram of the filter material fiber filtration mechanism. 7. Filtering mechanism of masks 1. Diffusion deposition The particle diffuses and displaces to the filter fiber by Brownian motion, and is adsorbed by molecular attraction. It is easiest to capture small scale particles, fine fibers and particles moving at low speed. 2. Intercepted deposit Larger particles moving with the air flow are retained by the mechanical sieving action of the filter material. The ratio of the particle diameter to the diameter of the filter membrane fibers affects the interception efficiency. 3. Inertial deposition When the particles pass through the curved mesh channel of the filter material, the particles break away from the airflow due to inertia and hit the filter fiber, and are trapped by molecular attraction. The interception effect is good when the particles are large, the density is high and the speed is fast. 4. Electrostatic attraction deposition Deposition of particles by the electrostatic action of the filter fibers. The smaller the particle, the stronger the deposition effect of 1 and 4, and the larger the particle, the better the effect of 2 and 3,Against Bacteria Breathable KN95 Face Mask, so it is not that the smaller the particle is, the more difficult it is to be filtered. Combined with the synergistic effect of the four filtration mechanisms, the most permeable particle size range of common mechanical filter media is 0.1 µm to 0.3 µm (see the relationship between filter media penetration rate and particle size). Comprehensive arrangement Editor: Kang Ming returns to Sohu to see more Responsible Editor:. zjyuan-group.com
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