What is a Gasket?
A gasket is an elastomeric component that covers the intersection between two surfaces. They are usually manufactured from a variety of materials, including rubber, synthetic material, or paper, metal, copper, and foam. This flexible element can be used for a broad scope of purposes due to its functionality. These include anti-vibration, packaging, hygiene, noise and sound reduction, and most importantly, its most common use, sealing.
Types of Gaskets
There are three types of gaskets used in process piping.
Most common materials used for this type of gaskets are Graphite, Rubber, Teflon, PTFE and Compressed Non-Asbestos Fiber (CNAF). These gaskets are also known as a Soft gasket. These types of gaskets are used with low-pressure class flanges such as 150 and 300 Class and also in low. Non-Metallic gaskets are cheapest and easily available
Metal Gasket / Ring Joint Gasket / RTJ Gasket
Metal gaskets are manufactured from a material such as Soft iron, Low Carbon steel, Stainless Steel, Monel, and Inconel. These gaskets are also known as ring gasket or RTJ gaskets. Metallic gaskets are used in high-pressure class flanges, normally above 900 Class, they can also be used for high-temperature. They are very robust & most costly
Composite Gasket or Semi-Metallic
Composite gaskets are a combination of metal and non-metal material. Different types of combination of materials are possible based on service requirement.
Spiral Wound Gasket
The most widely used composite type gasket is a Spiral Wound Gasket. It is suitable for wide range of pressure and temperature class. Normally Graphite or PTFE used as filler material & stainless steel or other exotic material is used as the winding material. There are three components in spiral wound gasket. Inner & Outer ring, filler material, and winding material. However, sometimes an inner ring is not used. The inner ring is used to provide additional support to the winding material. The winding is an alternative layer of filler material and winding material. The filler material is a soft material such as graphite and PTFE and winding material is a thin sheet of metal.