A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression.

Gasket Specifications

After determining that a gasket—as opposed to a shim or an o-ring—is the appropriate device for a given application, several other factors must be taken into account to choose a well-suited design. There are numerous types of gaskets, though many share similar features and may be capable of handling related tasks. Some of the most common varieties of gasket include:

• Jacketed Gaskets: 

  This form merges the efficiency and flexibility of soft gaskets (made of rubber or plastic) with the resistance and durability of an external metal coating. A single-jacket has soft filler with metal coverage along one face of the gasket, while a double-jacketed version has a fully coated metal facing, providing improved temperature, pressure, and corrosion resistance. Other variations include corrugated jacketed gaskets, and French Style jackets, which provide coating on either the inside or outside of the gaskets

• Solid Gaskets: 

  Solid gaskets are typically formed of metal and are a relatively inexpensive alternative to jacketed gaskets. They have high thermal and pressure resistance, though they require higher compression force to form a seal and are usually effective only against surfaces that are harder than the metal itself.

• Spiral Wound Gaskets:
  

  This type of gasket is formed by combining metal with softer plastics or synthetic rubber in a winding shape, often reinforced with additional layers of metal without filler. Its unique design yields high thermal and physical stress resistance, coupled with flexibility and resilient sealing. Spiral wound gaskets are often used in piping, pumping, and heat exchange system.

• Kammprofile Gaskets:

  The Kammprofile design contains a corrugated metal core covered with a malleable sealing material attached to both of its sides. This structure focuses physical stress onto the surface sealant, creating tight seals along the gasket’s edges while retaining the device’s flexibility and strong tensile core. Kammprofile gaskets provide reliable support in heat exchange systems and have improved cost-effectiveness due to their capacity for repair.

Metal Gaskets

Many types of gaskets are constructed from metal or a mixture of metal and non-metal materials. These gaskets are typically formed with aluminum, copper, nickel, steel, stainless steel, or brass. These materials provide a high level of thermal, corrosive, and pressure resistance, along with excellent durability and tensile strength. On the other hand, metals require elevated amounts of compressive force to form a seal and have limited flexibility for multiple applications. For these reasons, metals are often used in combination with rubber or plastic compounds, otherwise known as “soft fillers.”

Rubber and Plastic Gaskets

Due to its elastomeric properties, rubber is a popular material for gasket production. Since they can undergo a high degree of deformation without permanent damage or loss of attributes, rubber gaskets can form very tight seals within a wide range of applications. Some types of rubber frequently used in gasket manufacturing include nitril, viton, and neoprene. Certain polymers, such as thermoplastic elastomer, thermoplastic rubber, and polyvinyl chloride, display qualities similar to those of rubber and are also common in gasket production.

Silicone Gaskets

Silicone is a valuable gasket material because it displays strong resistance to extreme temperatures. Silicone-based gaskets can have operating temperatures that range between roughly -140 degrees to 480 degrees Fahrenheit. In addition, their resistance to ultraviolet light makes them useful in outdoor settings, while their flame tolerance within a certain thickness range has applications in electronics and transit industries. Silicone gaskets come in foam and sponge varieties, and can be reinforced with other materials to improve tensile strength or adjust thermal and electrical conductivity.

Compression Testing

An important characteristic for industrial gaskets is their capacity for tolerating compressive loads. Evaluations, such as the hot compression test, can be used to gauge a specific gasket’s ability to withstand various weights and temperatures. Typically, a gasket is placed between the exertion bolts of a hydraulic press. Temperature is increased, often up to nearly 600 degrees Fahrenheit, at an incremental rate over a given period of time while the press exerts constant load pressure on the gasket. Any decreases in material thickness are measured and used to assess the gasket’s effectiveness. Tests such as this can be helpful in selecting a gasket or deciding upon a given material or design configuration.