Non Metallic Gaskets
These are made from materials that compress easily, such as elastomers like nitrile, (NBR,) EPDM and silicone, as well as graphite, PTFE and fibrous materials. Their corrosion resistance is good but they are limited in the temperatures they can handle. Nitrile gaskets for example only work from -60 to 250°F (-51 to 121°C) and EPDM is only slightly better with a range of -70°F to 350°F (-57°C to 177°C). Silicone gaskets will however go up to 500°F (260°C) and PTFE is effective from cryogenic temperatures up to 450°F (232°C).
Full face gasket types are suitable for use with flat-face (FF) flanges and flat-ring gasket types are suitable for use with raised face (RF) flanges.
Soft gaskets are also limited in their ability to handle high pressures. The best applications are those involving sealing variable gaps as might be found around the doors of an electrical enclosure.
PTEF Joint Sealing
Expended PTEF Gasket
PTFE Envelope Gaskets
Rubber Gaskets & Seals
Graphite Moulded Rings
Soft Cut Gaskets
Semi Metallic Gaskets
Bridging the gap between metallic gaskets and soft gaskets, the semi-metallics combine features of each. Those gaskets are composites of metal and non-metallic materials. The metal is intended to offer strength and resiliency while the non-metallic portion of a gasket provides conformability and sealability Commonly used semi-metallic are spiral wound, metal jacketed, Cam profile and a variety of metal-reinforced graphite gaskets.
Semi metallic gaskets are designed for the widest range of operating conditions of temperature and pressure. Semi-metallic are used on raised face, male-andfemale and tongue-and –groove flanges.
Spiral wound gaskets are used for high temperature and high-pressure applications. The main parts of spiral wound gasket are metallic windings and filler material. The criteria for material selection of windings are: corrosive nature, fluid concentration, operating temperature and material cost. Commonly used material for winding are Stainless steel 304, 316 and 321.Alternate winding materials also can be used depending upon the services. General filler material used are Asbestos and graphite. Graphite filler are recommended for very high temperature application.
For proper positioning, spiral wound gaskets are provided with outer centering ring made up of Carbon Steel. In Vacuum service application they are provided with inner ring. The material of the ring should be compatible with the process fluid.
Spiral wound gasket is recommended with flange face finish of 63-250 AARH.
Heat Exchanger Gasket
Kamm Profile Gakset
Metal Jacketed Gasket
Spiral wound Gasket
Tanged Graphite Gaskets
Metallic gasket is fabricated from one or a combination of metal to the desired shape and size. Common metallic gasket is ring-joint gasket and lens rings.
It is suitable for high-pressure and temperature applications and require high bolt load to seal.
That allows it to resist pressures as high as 10,000 psi but also means it has virtually no compression. Very high bolt loads are needed to create enough deformation for joint sealing.
Metallic gaskets are vulnerable to galvanic corrosion. To minimize problems the gasket metal should be close to the flange material on the electrochemical scale. Alternatively, the material should be chosen to make the gasket the sacrificial element.
Double Cone & Delta gaskets
Metal O Rings Alummunium
Metal O Rings Copper
API 601– Metallic Gasket for Refinery Piping
BS 3381– Spiral Wound Gaskets to suit BS 1560 Flanges
ANSI B 16.20– Metallic Gasket for Steel Pipe Flanges, Ring Joint, Spiral Wound and Jacketed
ANSI B 16.21– Non-Metallic flat Gasket for Pipe Flanges