Siphon: Types and designs at a glance

The siphon, as we know in the bathroom, is just one of the possible types of siphons. What other shapes and designs are there, and where differently shaped siphons are used everywhere, read this post.

Tasks of the siphon

Basically, a siphon is always an odor trap. It is necessary because decay processes take place in sewer pipes as well as in sewage pipes, producing particularly bad smells.

Since the sewer and sewer system is connected to the drainage system of a sink or sink through open pipes, these foul odors would rise above the pipes and spread throughout the room. To prevent this, there is a siphon.


The functional principle of a siphon is relatively simple: water stays in a special shape of the siphon so that gases can not penetrate upwards. This water level is called "barrier water".

The height of the barrier water level is specified by standards (DIN 1986). For the sanitary drains 50 mm are demanded there. The water in the sewer pipe thus also needs a certain minimum pressure in order to overcome the siphon.

construction methods

The known from the sink design as u-shaped pipe bend is also called tube siphon. But there are also other species.

design typeuse
FlaschensiphonWith very low available installation depths, such as shower trays
Baffle closureNo use in sanitary area, except urinals as oil siphon


The drain pipe leads in this siphon in a "cup" with barrier liquid from which the sewage pipe leads away horizontally.

Baffle closure

The siphon here represents a liquid-filled obstacle immersed in the water. This principle is also used in other areas of technology. A so-called waterless urinal has a specially designed oil siphon.


The bell siphon is a bit more complicated. The barrier fluid is here under a bell, the air pressure prevents the rising of the liquid.

Tips & Tricks

Gas closures occur - according to the same construction principle - in many other areas. Most are simple constructions based on the principle of siphons.

Video Board: 3 methods of DRAFTING