Gasket

A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression.

[4] It is usually desirable that the gasket be made from a material that is to some degree yielding such that it is able to deform and tightly fill the space it is designed for, including any slight irregularities.

Most industrial gasket applications involve bolts exerting compression well into the 14 MPa (2000 psi) range or higher.

Material examples are mineral, carbon or synthetic rubbers such as EPDM, Nitrile, Neoprene, Natural, SBR Insertion - each of which have unique properties suitable for different applications.

[3] Applications using sheet gaskets involve acids, corrosive chemicals, steam or mild caustics.

The key downside is that a solid metal must be greatly compressed in order to become flush with the flange head and prevent leakage.

The filler material in these gaskets acts as the sealing element, with the metal providing structural support.

The constant seating stress gasket consists of two components; a solid carrier ring of a suitable material, such as stainless steel, and two sealing elements of some compressible material installed within two opposing channels, one channel on either side of the carrier ring.

Constant seating stress gaskets derive their name from the fact that the carrier ring profile takes flange rotation (deflection under bolt preload) into consideration.

Further, because the sealing elements are fully confined by the flange faces in opposing channels on the carrier ring, any in-service compressive forces acting on the gasket are transmitted through the carrier ring and avoid any further compression of the sealing elements, thus maintaining a 'constant' gasket seating stress while in-service.

When in use, the compressed gasket has a larger amount of metal at the two tips where contact is made (due to the shell/piece interaction) and these two places bear the burden of sealing the process.

[9] Kammprofile gaskets (sometimes spelled "Camprofile" due to their design resembling the profile of a camshaft, which is a rotating component in internal combustion engines.

Kammprofile has a high capital cost for most applications but this is countered by long life and increased reliability.

They are fully CNC machine manufactured from similar materials but the design of the gaskets has eliminated inherent short comings.

The added "Stop Step" prevents the Fishbone gaskets from being over compressed/crushed, often caused by hot torque techniques on plant start up.

They are mostly used in offshore oil- and gas pipelines and are designed to work under extremely high pressure.

Soft gaskets are used in applications such as heat exchangers, compressors, bonnet valve and pipe flanges.

The movement of the ring packing (RTJ) can be described as an irregular flow in the groove of the deformed sealing flange due to the axial compressive load.

Many gaskets contain minor improvements to increase or infer acceptable operating conditions: Uneven pressure can be caused by a variety of factors.

With asymmetric connections, the seal surfaces will be more or less deformed and the pressure reduced, the running load, prone to leakage.

Due to vibration, temperature changes, and other factors such as spiral wound gasket stress relaxation, the bolt tension will gradually decrease, resulting in loss of torque, causing a leak.