The sinuses are air-filled cavities. 1  They are located: 2  Within the bony structure of the cheeks. 3  Behind the forehead and eyebrows. 4  On either side of the bridge of the nose. 5  Behind the nose directly in front of the brain.
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.
To avoid extrusion at high temperature, reduce the extrusion gap, increase the seal material hardness or add a back-up ring to the o-ring but will require a wider gland. Pressure Cycling . Cycling pressure can cause the o-ring to move back and forth within the gland. This motion can damage seals with low abrasion resistant materials. A higher durometer or an abrasion resistant material is recommended for these applications. Need O-Rings Fast?