O-rings are also known as a toric or packing joints, and are the most widely-used seal in the industry. During assembly, o-rings sit in a groove and are compressed between 2 or more parts to form its shape. They are easy to install and may be used as a double-acting seal. O-Rings are both inexpensive, and reliable.
Specialty o-rings can seal pressures of up to 800 PSI. If your application requires a seal pressure of over 800 PSI, backup o-rings should be kept in mind.
O-rings are not used for rotating shaft applications; their typical use is that of a reciprocating seal. They are measured by their inner diameter and cross section, and can be even more categorized by type (such as the material used to manufacture).
In order to correctly assess o-ring needs, one should consider the application’s sealing pressure, lubrication needs, size, and chemical compatibility.