What is a gas mask?

      Gas mask is a personal special labor protection equipment, as well as individual protective equipment. It is worn on the head to protect the respiratory organs, eyes, and face of individuals, and to prevent harm from toxic substances such as gases, dust, bacteria, toxic and harmful gases or vapors. Gas masks are widely used in fields such as petroleum, chemical, mining, metallurgy, military, firefighting, disaster relief, health and epidemic prevention, technology and environmental protection, machinery manufacturing, etc. They can also play an important role in protecting the personal respiratory system in cities with severe haze and photochemical smog. Gas masks can be divided into full masks and half masks in terms of appearance, with full masks further divided into positive pressure and negative pressure types.

Historical evolution

      On April 22, 1915, in order to reverse the unfavorable situation of the war, the German side unexpectedly released 180 tons of chlorine gas onto the positions where the British and French armies were gathering, causing 5000 coalition officers and soldiers to be poisoned and die on the spot. This was the first large-scale gas war in world military history. The British and French coalition forces, which suffered significant losses after this battle, immediately urged their own government to manufacture anti virus equipment as soon as possible. Soon, dozens of scientists from both countries were sent to areas that had been previously attacked by the German side with chlorine gas for investigation and evidence collection research. They were surprised to find that a large number of wild animals on the battlefield, including birds in the forest, dormant frogs, and exposed insects, had all been poisoned and died one after another. Only the local behemoth, the wild boar, survived unscathed. Through research and experimentation, scientists have found that wild boars are particularly fond of using their powerful long mouths to arch the soil and search for the roots and stems of plants and some small animals in the field. When they smell a strong pungent odor, they often use arches to avoid it. When the German army launched a surprise attack with poison gas, the clever wild boar arched its mouth and nose into the soil to avoid the disaster. After further scientific analysis, it can be concluded that due to the wild boars using their mouths to arch the ground, the soft soil particles adsorb and filter out toxic gases, allowing them to survive.

      Scientists from both countries have gained inspiration from this, and based on the principle that soil can filter toxins, they have selected charcoal that can adsorb toxic substances and keep the air flowing. They quickly designed and manufactured the world's first gas masks that resemble the shape of wild boar mouths. In late February 1916, during the brutal Battle of Verdun, the German and French armies resorted to the old trick of releasing toxic gas on their positions. At this time, the French army had basically put on gas masks, effectively resisting the German gas attacks. At that time, young British scientist Fleming (who discovered the magical penicillin in 1881-1955 and 1928) excitedly said, "Wow, the cute wild boar saved the soldiers!"

Composition structure

      Gas masks, as personal protective equipment, are used to provide effective protection for personnel's respiratory organs, eyes, and facial skin. The mask is composed of a mask, a gas duct, and a gas filter. The mask can be directly connected to the gas filter or a gas filter box, which is called a direct connection type; Alternatively, it can be used by connecting a gas duct to a filter canister and filter box, known as a catheter type. Anti virus masks can be selected from various models of gas filtration tanks according to protection requirements, and can be applied in chemical, warehouse, scientific research, and various toxic and harmful working environments.

      Gas masks are mainly composed of filtering elements, cover bodies, eye windows, exhalation communication devices, and headbands, each of which has its own responsibilities and can work together harmoniously.

Filter element

      The filter element is the loyal guard on the gas mask, allowing only the essential clean air that the human body cannot lack to pass through. Masks from various countries around the world come in a variety of shapes, and the filtering elements on the masks also have different shapes. However, the design ideas for their internal structures are similar. It is equipped with a filter layer inside to deal with aerosols (small particles suspended in the air), also known as a smoke filter layer, which is actually a specially made filter paper. It needs to efficiently filter out harmful aerosol particles while not creating significant resistance to human respiration.

      The filter element is also equipped with anti toxic charcoal specifically designed to deal with toxic gas vapors. It is different from ordinary civilian activated carbon. Anti toxic carbon not only needs to have a very developed microporous structure to have a large enough stomach to eat as many toxins as possible, but also needs to have fully developed mesopores and macropores to make the road with adsorption effect smooth and meet the requirements of adsorption rate. In addition to requiring a reasonable pore structure, antivirus charcoal also needs to be treated with special chemical agents, because physical adsorption alone is not enough to deal with various toxins. Catalysts must be used to carry out physical and chemical reactions, making it a "drug addict" with extraordinary skills.

      The new antivirus charcoal has a strong ability to deal with toxins. However, over time, antivirus charcoal will develop an inertness, which is the natural aging process. To prevent this kind of inertia from appearing too early, mask designers must apply anti-aging treatment to the anti-venom charcoal. Catalysis and aging are two deeply rooted disciplines, and their key technologies are kept secret by various countries.

      Some filter elements are installed on the left side of the mask; Some are placed in the lower jaw; Some even come with air ducts, no matter how cleverly placed, they look like a burden. It is said that an enzyme that can "eat" toxins has been discovered, and if this enzyme is used on filter elements, the mask design will undergo a qualitative leap.

Mask body

      The mask body is the main component that integrates the various components of a gas mask. At first glance, it looks like nothing more than an eraser, without much knowledge. However, it needs to be suitable for people with various head types to wear, which should be tightly sealed to prevent toxins from entering and to avoid causing facial pain. The sealing frame is made of a piece of rubber and is called a single piece sealing frame. It can match the face and has a very simple structure and manufacturing process, but wearing it often causes unbearable tenderness to the protruding parts of the face, and the dynamic airtightness is also poor.

      In the future, a folded edge closed frame structure for SLR emerged. It is based on the flat sealing frame and adds a circle of anti folding edges, relying on the elastic tension of rubber to form a sealing force on the human face. When exhaling, the pressure inside the mask is greater than the external pressure, which is a positive pressure airtightness good sealing frame structure. The folded edge sealing frame of a DSLR is undoubtedly a big step forward compared to a single piece sealing frame, however, there is still a significant gap in meeting tactical usage requirements.

       The S6 mask from the UK is recognized internationally as an advanced mask, characterized by the use of an air cushion tube sealed frame structure. This sealing frame is composed of a rubber tube filled with a certain amount of gas in the middle and sealed. There is a pressure regulating valve installed on the pipe, which can make the air cushion pipe "bulge" or "deflate" slightly, making it closely match the faces of people with various facial shapes. Due to the equal pressure exerted by the gas inside the air cushion tube in all directions, a balanced pressure is generated on the human face, and long-term wear does not cause local tenderness. But this type of close fitting frame production process is complex, and the product qualification rate is low.

Product classification-Filter type

      Composed of a mask and a filter canister (or filter element). The mask includes components such as a hood, eye windows, intercom, breathing valve, and headband (or helmet). The gas filter tank is used to purify toxic gases, and is filled with a filter layer and adsorbent. These two materials can also be mixed to form a filter plate and assembled into a filter element. A lighter (around 200 grams) canister or filter element can be directly connected to the mask, while a heavier canister is connected to the mask through a gas duct.