An O-ring is a round ring that is used as a gasket for sealing a connection. O-rings are typically constructed out of polyurethane, silicone, neoprene, nitrile rubber or fluorocarbon. These rings are commonly used in mechanical applications, such as pipe connections, and help to ensure a tight seal between two objects. O-rings are designed to be seated in a groove or housing that keeps the ring in place. Once in its track, the ring is compressed between the two pieces and, in turn, creates a strong seal where they meet.
The seal that a rubber or plastic O-ring creates can either exist in a motionless joint, such as between piping, or a movable joint, such as a hydraulic cylinder. However, movable joints often require that the O-ring be lubricated. In a moving enclosure this ensures slower deterioration of the O-ring and therefore, extends the useful life of the product.
O-rings are both inexpensive and simple in design and are therefore very popular in manufacturing and industry. If mounted correctly, O-rings can withstand a very large amount of pressure and are therefore used in many applications where leaks or loss of pressure are unacceptable. For instance, O-rings used in hydraulic cylinders prevent leakage of hydraulic fluid and allow for the system to create and withstand the pressures required for operation.
O-rings are even used in highly technical construction such as space ships and other aircraft. A faulty O-ring was deemed the cause of the Space Shuttle Challenger catastrophe in 1986. An O-ring used in the manufacture of the solid rocket booster did not seal as expected due to the cold weather conditions upon launch. Consequently, the ship exploded after only 73 seconds into flight. This highlights the importance of the O-ring as well as its versatility.
Of course, different types of O-rings made out of different materials are used for various tasks. The O-ring needs to be matched to its application. Do not confuse however, similar inventions that are not round. These objects are brother to the O-ring and are instead simply called seals.