What is a Gasket?
- Gaskets are a type of mechanical seal that inhibits leakage by filling the gap between static mating surfaces. As the gasket is deformed by a compressive force, it conforms to the profile of the surface and fills the gaps between its peaks and troughs.
- Depending on the type of material used and construction, gaskets can be divided into three main categories: non-metallic, semi-metallic, and metallic gaskets.
- Non-metallic gaskets are either made of homogeneous materials such as flexible graphite sheet and virgin PTFE, or a composite of fibers and granules embedded in an elastomer resin. These types of gaskets are suited for low to medium pressure applications.
- Sem-metallic gaskets are composites of metallic and non-metallic materials. The metallic component provides structural strength and increased toughness, while the non-metallic part offers enhanced sealing.
- Metallic gaskets are used for extremely high pressure and temperature applications.
- In selecting a gasket, it is important to evaluate the process fluid‘s pressure, temperature, and chemistry. For non-metallic gaskets, take note of the thickness. Thinner gaskets with the same ratings have better sealing performance.
- Improper compression, overheating, gasket reuse, and chemical attack are the most common reasons why gaskets fail.