The installation space of an O-ring is called a “groove”. The size is defined by its width and depth. The roundness (radius) of the groove corners is also specified.
In order to achieve an optimum sealing effect, it is essential that the installation space is designed in accordance with standards. An incorrectly designed installation space is still one of the main reasons for O-ring failure.
A rectangular installation space for the O-ring is by far the most common. In addition to the rectangular groove, there are also triangular and dovetail grooves.
Triangular grooves are used for vacuum applications. It is important that almost 100% of the installation space is filled and the compression is approx. 30%.
Dovetail grooves are used, for example, if the O-ring has to be mounted overhead and would fall out during assembly in a rectangular installation space.