Gravity pipeline

As nonpressure duct (in tunnel form and free-flow tunnel or mirror tunnel ) a pipe or a section is called such, enters the water according to the law of gravity from a higher starting point at a deeper end, wherein the cross section is not fully traversed usually so that, in contrast to a pressure pipeline or a pressure tunnel , a free liquid surface usually remains. The line is therefore not completely filled by the liquid, but a volume of air remains that begins at the upper end of the gravity line and, depending on the pressure and gas solubility, extends more or less far downwards.

Since the water in a gravity pipeline is only conveyed by gravity, the gravity pipeline is also known as a gravity pipeline . Gravitational pipes usually transport water (wastewater) using the free gradient without additional energy from point A to point B. A normal pressure increase in the inlet area (pump delivery) or pressure reduction in the outlet area ( vacuum drainage ) is not necessary if the energy level is sufficient.