Metallic Sealing Rings

Metal O and C rings are used as a deformable seal in a static sealing situation. The ring is located between two flanges or similar and undergoes a controlled compression. They are defined by their free height which is the cross section in the axial direction of the seal. The free height of the seal is compressed down to the groove depth.

• Temperature range from cryogenic to 850°C
• Pressure range from ultra high vacuum to 1,000 MPa
• Compatible with a large range of media
• Corrosion resistant and radiation tolerant
• Simple and reliable sealing
• No 'out gassing'
• Wide range of sizes up to 2.3m (90")
• Available in non-circular configurations

The resistance of the ring to compression enables it to form an effective seal when compressed. The resilient effect of the seal is increased by pressurising the internal volume of the ring and is known as gas filled.

If the system to be sealed is a very high pressure - this can be used to provide additional sealing effect. System actuation is achieved by allowing the high pressure to enter the seal through either vent holes in an O ring, or through the open slot of a C ring.

Metal O ring seals have a certain degree of elasticity. This is known as springback. The springback is the elastic part of the seal deflection when it is installed in a groove.

This influences the seal’s ability to absorb or compensate for hardware variations due to temperature loadings, and thus maintain the seal integrity.

Metal C rings obtain this springback with a spring energiser further maintaining the seals integrity in applications and hardware variations as above.

A softer plating or coating material can be applied to Metal O and C rings to maximize sealing performance in difficult applications. The soft coating material yields during the ring compression and fills any surface machining marks. Most common plating and coating is Silver or PTFE.