Unique Industrial Packings Pvt. Ltd.

Malad West, Mumbai, Maharashtra

The solid metal gasket provides an excellent mechanical joint and has almost universal acceptance in the oil, petroleum and chemical processing industries where high mechanical and thermal performance is required. The type R oval configuration is the original ring joint design and was followed by the type R octagonal which offered more specific sealing contact areas. Details of these joints are given in ASME B 16.20 and API 6A standards. The gaskets sit in a recess in the flange face having 23 angled walls. The RX joints are an unequal bevel octagonal ring, and are considered to be a pressure energized or pressure-assisted seal. The BX is also octagonal, though shorter in profile and designed to go into a recess that comes metal-to-metal when the flanges are tightened. These are used on very high pressure flanges up to 20, 000 p.s.i. rating. Gasket metal should be selected to suit the service conditions and should have hardness lower than the flange metal.

These gaskets are specially designed and widely used for heat exchangers, autoclaves, columns, pressure vessels, valve bonnets, etc. The gaskets are manufactured from a soft, pliable filler core surrounded by a metal jacket, chemically and thermally resistant to the working conditions. Metal jacket may totally or partially enclose the filler. Metals such as soft iron, carbon steel and stainless steel are used in annealed condition to encase a soft filler material, usually non-asbestos millboard. Alternative fillers include expanded graphite, PTFE, compressed non-asbestos fibre and ceramic fibre.

When gasket width has to be narrow as in cylinder heads and exhaust manifold on internal combustion engines, compressed asbestos fibre (CAF) sheets and compressed asbestos-free (non-asbestos) fibre sheets are reinforced with mesh wire gauge to resist the blow out. Sheet jointing of pure exfoliated graphite are reinforced with a central layer of 0.1mm thick tanged stainless steel to give them extra strength for easy of handling and fitting. In these gaskets the graphite is compressed onto the perforated metal sheet to give a secure mechanical lock without adhesive. Extra strength to such sheets is also given by bonding a central layer of stainless steel or nickel foils.

Corrugated metallic gaskets have a corrugated metal core (normally stainless steel), with expanded graphite facings. They are used for standard pipeline duties, and heat exchangers.

Metal gaskets with grooved faces have proved to be very effective for sealing flanged connections, and are particularly suited to applications, pressures and fluctuating conditions are encountered. Typical applications are gaskets for heat exchangers, vessels and reactors, and various flanged connection. commonly known as kammprofile gaskets, the grooves are machines in accordance with the profile specified in DIN 2697 adn are available in a range of styles and materials. non-metalic covering layers ensure that flanges are not damaged, even at high loadings, adn provide excellent sealing properties when supported by the grooved metallic gasket. kammprofile gaskets are use in heat exchangers may be fitting with grooved partition bars.