Self sealing cover plate gaskets are used in high pressure, large diameter apparatus where flanged connection are impractical. The internal pressure of the vessel creates the forces that are necessary to provide an effective seal at operating conditions. A primary seal is created by applying a certain bolt force which ensures that the start up and hydro testing can be performed without leakages. The most common styles of graphite seals are Klinger P71, P74 and 75 as shown. The seals can be manufactured in sizes up to 1200 mm OD. They are manufactured from a minimum 98 % pure chemically expanded graphite with a density of 1 g/cm³. The density of the final gasket is usually 1.6 g/cm³, but for very high pressures this can be increased to 1.8 g/cm³. Also available in profile series P80, chemically pure expanded graphite, reinforced with stainless steel lamellae For details on the steel capping of self sealing cover plate gaskets contact Klinger