Sprinkler is an important part of wet-type auto spraying system. It is usually installed inside the building and structures with light fire danger, medium fire danger and heavy fire danger, such as workshop, warehouse, hotel, shop, recreational place, hospital, cinema, office building and garage.The sprinkler is composed of sprinkler frame, sealant and glass bulb. It is to be installed in the protective district via ductwork, acting as a fire detector and auto sprayer. In case of fire inside the protective district, the atmosphere temperature rises up and the liquid inside the glass bulb expands after being heated and explodes after reaching the operating temperature of the glass ball. The sealant drops and the sprinkler sprays to the protective district for fire extinguishments subject to the preset shape of spraying.