The specific operating logic is as follows: Air blockers are usually installed at critical nodes where backflow may occur (such as between drainage outlets and receiving water bodies, parallel areas between sewage pipelines and clean water pipelines, etc.), with specific structured channels and air chambers inside. When the medium in the pipeline flows normally in the forward direction, the medium can be smoothly discharged through the forward channel of the blocker. At this time, the air chamber is isolated from the medium channel and does not affect normal flow; When negative pressure, siphon effect, or increased back pressure occurs in the pipeline, causing the medium to reflux, the air chamber of the blocker will automatically communicate with the atmosphere, allowing air to enter the pipeline system and breaking the pressure conditions that form reflux (such as breaking the siphon vacuum). At the same time, the existence of air gaps prevents the reflux medium from forming a continuous fluid column, and can only stay or fall back in specific areas of the blocker, unable to cross the air gap into the clean side pipeline, thus achieving the protective purpose of preventing cross contamination.