The pressure difference between them is negligible. Therefore, p1-rhogh1>; P2-ρgh2, then the pressure at the left end of A is greater than that at the right end of A, and water moves in one direction under the action of atmospheric pressure and liquid pressure.

In 1960s, several Swedish scientists applied siphon principle to modern buildings, and initially solved the rainwater drainage system on the roof of buildings. At that time, in the early stage of research, the whole pipe pressure flow system was adopted.

As a result, the rainwater drainage system of pipeline roof has made a major breakthrough. Siphon principle has applications in building drainage, municipal drainage, water conservancy projects and so on.

Baidu encyclopedia-siphon