According to the protection principle, anti-virus half masks can be divided into filtering anti-virus masks and isolated anti-virus masks.
①Filter anti-virus mask
It consists of a face mask and a canister (or filter element). The mask includes parts such as a mask body, an eye window, a talk device, a breathing valve, and a headband (or helmet). The poison canister is used to purify the poisoned air, and contains the smoke filter layer and the sorbent. The two materials can also be mixed to make a filter plate and assembled into a filter element. The lighter (about 200 grams) canister or filter element can be directly connected to the mask, and the heavier canister is connected to the mask through the air guide tube.
②Isolated anti-virus mask
Oxygen is provided by the mask itself, which is divided into three types: gas storage type, oxygen storage type and chemical student oxygen type. The isolated mask is mainly used in high concentration of poisoned air (when the volume concentration is greater than 1%), or in special occasions such as high altitude, underwater or closed cabins where oxygen is deficient.