: Historically used in underwater tunnels and bridge foundations (caissons) to transition workers from atmospheric pressure to high-pressure work zones.

: Pharmaceutical facilities use them to prevent contamination by maintaining a pressure cascade between rooms. 2. Fluid Blockage (Plumbing & Irrigation)

: Air can enter a system during maintenance, pump restarts, or through dissolution in the liquid itself. air lock - Students | Britannica Kids | Homework Help

An air lock (or vapor lock) occurs when gas becomes trapped in a high point of a liquid-filled pipe system, partially or completely blocking the flow .

An is a device or physical phenomenon involving trapped air that regulates passage between different pressures or blocks the flow of liquids . Depending on the field—whether aerospace, plumbing, or medicine—an "air lock" serves very different purposes. 1. Pressure Regulation (Engineering & Aerospace)

: It can lead to sputtering faucets, no water flow in gravity-fed systems, or the failure of pumps that rely on liquid for lubrication.