Gaskets and Their Types...

Gaskets and Their Types The cost of leaky joints in a steel plant can be staggering. Gaskets perform an important role in the prevention of fluid leakage from pipes and equipment parts in the steel plant. A gasket is a compressible material, or a combination of materials, which when clamped between two stationary members prevents the passage of the media across those members. The gasket material selected must be capable of sealing mating surfaces, resistant to the medium being sealed, and able to withstand the application temperatures and pressures. Generally, gaskets are called upon to affect a seal across the faces of contact with the flanges. Permeation of the media through the body of the gasket is also a possibility depending on material, confined media, and acceptable leakage rate. A gasket is normally placed in between two objects in order to prevent leakage of any kind of the pressurized or not pressurized media. Most important is the compression set of a gasket to adapt to flange irregularities and to any dimensional changes of the flange system caused by temperature changes during operation. Gaskets are used to create a static seal between two stationary members of a mechanical assembly and to maintain that seal under operating conditions which may vary dependent upon changes in pressures and temperatures. If it is possible to have perfectly mated flanges and if it is possible to maintain an intimate contact of these perfectly mated flanges throughout the extremes of operating conditions, then the gaskets are not required.  However this is virtually impossible because of the following. Size of the flanges and/or the vessel Difficulty in maintaining extremely smooth flange finishes during handling and assembly Corrosion and erosion of the flange surfaces during operations Large number of flanged joints needed...