Gaskets

Gaskets: Ensuring Reliable Mechanical Seals

The primary purpose of a gasket is to create an effective mechanical seal by filling the gaps between two fixed mating surfaces. Achieving a perfectly smooth surface is virtually impossible, and even the most precisely machined surfaces contain microscopic irregularities. When these surfaces are joined, small voids remain due to micro protrusions, which can lead to fluid leakage.

Gaskets act as a compliant layer, filling these valleys to prevent leakage by conforming surface profile under compression thus ensuring seals. To function effectively, the gasket material should generally be softer than the parent flange materials, allowing it to conform to surface imperfections and provide a reliable seal under operating conditions.

Gaskets are vailable in a wide range of shapes, sizes, and materials, gaskets are carefully selected based on pressure, temperature, and the type of fluid they will encounter. These versatile components are indispensable across diverse industries, from automotive and aerospace to pharmaceuticals and chemical processing, wherever safe and efficient fluid handling is required. Common applications include pipelines, heat exchangers, tanks, internal combustion engines, and many other mechanical systems.

Gasket Material

Material composition of a gasket is the most critical factor that directly impact its performance, durabiliity, compatibility, chemcial resistance in harsh environment. Gasket are chosen based on temperature, pressure, chemcial compatibility, surface finish, flange type, environmental conditions (i.e. corrosion, UV and ozone exposure) and mechanical requirement. They can be broadly categorized into non-metallic, metallic and composite.

1. Non-Metallic Gaskets

These are made from material like rubber, cork, felt or graphite reinforced with fibers. They are usually flexible, compressible and ideal for flow temperature applications.

a. Rubber

Includes: NBR, EPDM, Silicone, Neoprene

Have excellent sealability for liquid and gasses

Good flexibility and resilience

Temperature typically ranges from -60 degC to 200 degC depending on type.

b. Cork

Compressible, conform well on irregular surfaces

Often used with oils and fuels

Can handle moderate pressure

c. Graphite

Excellent heat resistance upto 450 degC and remain chemically inert

Commonly used in steam systems, chemical and high temperature applications

Can withstand high temperatures

d. PTFE (Teflon)

Outstanding chemical resistance, very low friction

Suitable for aggressive chemicals, food and pharmaceutical industries

Operating temperature ranges from -200 degC to 260 degC.

2. Metallic Gaskets

These are made of metal and used in high-pressure and high-temperature applciations.

a. Spiral Wound Gaskets

Made of alternating layers of metal and filler (graphite or PTFE)

Used in high-pressure and high-temperature piping, heat exchangers

Excellent for flanges where leak tightness is critical

b. Ring-Type Joint (RTJ) Gaskets

Solid metal rings, often used in oil and gas pipelines

Designed for extremely high-pressure systems

c. Corrugated Metal Gaskets

Thin metal layers corrugated for flexibility

Often paired with a soft facing material for chemical resistance

3. Composite Gaskets

These are made of combined materials (i.e., metal+elastomer, graphite+steel) to achieve both flexibility and strength.

They offer excellent sealing performance for complex or high-stress applications Commonly used in pumps, compressors and heat exchangers