A pressure pipeline is a pipeline in which, in contrast to a gravity pipeline , there is overpressure compared to atmospheric pressure . Before a pressure line is put into operation, a pressure test must be carried out to determine whether the line is tight ( DIN 4044). Water, crude oil or natural gas are transported in pressure pipelines, but other media are also used. In addition to hot water, water vapor is also transported in district heating pipes. The longest pressure pipeline in the world is the friendship oil pipeline between Tatarstan and Brandenburg , at 5327 km .
Pressure pipelines do not depend on a natural gradient. The medium is transported through the overpressure in the line. A classic example are inner-city water supplies, where the necessary overpressure is provided by pumps or water towers. Pressure pipelines require a smaller diameter than gravity lines for the passage of the same volume flow , since the entire cross-section is used.
Free gradient pressure lines use the natural gradient and therefore do not require any external energy to operate. In contrast to gravity lines, however, a uniform gradient is not necessary. The line can also go through highs and lows.
In pressure drainage systems , pressure pipelines can be laid with stronger and more abrupt changes in the direction of flow than gravity lines. 90 ° bends are usually possible, while in the case of sewage pipes designed as horizontal gravity pipes, changes of direction to avoid blockages are usually carried out at an angle of 45 ° at the most.
A penstock is a special name for a penstock in the field of hydropower. It connects water storage and power house of a hydropower plant , such as B. in a pumped storage power plant , on the shortest route.
The culvert in open channels are technically penstocks, because the internal pressure is slightly higher than atmospheric pressure. However, they are usually designed according to the regulations for gravity lines, as long as no excessive turbulence is to be expected.
- pressure line on Lexikon.Wasser.de, accessed on 9 March 2018th
- Detlef Aigner: Free gradient pressure line , November 2002, Technical University of Dresden, Institute for Hydraulic Engineering and Technical Hydromechanics.
- Andreas Moser: Headwater pipeline with sections up to 80 ° inclination - Plankenbach electricity works (San Cassiano) ( Memento from April 2, 2015 in the Internet Archive ) (PDF; 162 kB), accessed on September 27, 2013.