The ZST closed glass sprinkler head is a key thermal sensing element in the "Automatic Sprinkler Fire Extinguishing System". The glass sphere is filled with organic solutions with different expansion coefficients. After thermal expansion at different temperatures, the glass sphere breaks and the water flow in the pipeline sprays towards different designed splash disks, spraying upwards, downwards or sideways, thus achieving the purpose of automatic sprinkler fire extinguishing. Suitable for automatic sprinkler fire extinguishing system pipelines in factories, hospitals, schools, airports, shopping malls, hotels, restaurants, entertainment venues, and basements with ambient temperatures not lower than 4 ℃ and not higher than 70 ℃. Product standard basis: CB5135.1-2003 "Automatic Sprinkler System Part 1: Sprinkler Head"