Gaskets are common in engines, appliances, boilers, tanks, etc. Therefore, they have become an active part of our everyday life, but what types of gasket material is available to choose from?
There are different types of gasket material, depending on the application and the properties required. You must consider the:
- Chemical resistance
- Temperature resistance
- Flexibility
- Friction
Now, irrespective of the type of material you settle for, a gasket can prevent the escape of air, gas, and water in commercial and industrial applications.
This function makes gaskets important in the operation of a good number of machines. Generally, gaskets are needful in oil, gas, and petrochemical generation.
What is a Gasket?
A gasket is a sealing material that is used to create a static seal between connecting flanges.
The seal is created at different operating conditions as well as pressure and temperature ratings.
In this case, the irregularities and microscopic spaces on the flange faces are filled with gaskets, which helps to retain fluids. As such, gaskets as a mechanical tool ensure a leak-proof sealing, which helps to prevent the leakage of liquids and gases from the flange’s joint.
Further, gaskets are usually formed from soft materials like rubber. Asides their use in sealing pipes to wade off fluid leakage, these tools also work with anti-vibration and mounting.
Types of Gaskets
There are various types of gaskets; however, the most common examples include:
- Custom made gaskets
- Flange gaskets used in piping
- Specific material properties for gaskets
- Gaskets used in vehicles such as boats, cars, planes, and trains
- Gaskets to achieve a particular function such as high or low pressure, temperature, or chemical resistance
Various Types of Gasket Material
Chemicals, fuel, tremendous pressure, and extreme temperature often encompass the gaskets. As such, the chosen material must be resistant to chemicals, abrasion, and rust-free.
A choice of which is also dependent on the application of it. The different types of gasket material to choose from include:
1. Metallic Gaskets:
Metallic gaskets are also called ring gaskets or RTJ (ring-type-joint) gaskets. A combination of metals gives these gaskets the correct shape and size. Some materials used in the creation of metallic gaskets include low carbon steel, stainless steel, soft iron, and monel.
Metallic gaskets are common in valves and pipework as well as assemblies in refineries. They are also used in high-pressure class flanges (e.g. oil and gas supply production), and high-temperature applications to provide excellent, reliable sealing.
On the other hand, there must be high tension bolting during the use of metallic gaskets.
2. Non-metallic Gaskets:
Non-metallic gasket material is also known as a soft gasket, and this material can be compressed easily with low tension bolting. They can be used in heat exchangers, pipe flanges, and compressor valve gaskets.
The following materials create non-metallic gaskets:
- Compressed Non-Asbestos Fiber (CNAF)
- Teflon
- Rubber
- Graphite
- Aramid fiber
- Glass fiber
On the other hand, non-metallic gaskets have found use cases in low-pressure applications (around 150 and 300 class) and low temperatures applications. Despite this, graphite gaskets are common in high temperatures and work even in temperatures as high as 460 degrees centigrade.
These graphite materials are also used with flat-face and raised-face flanges where the full-face gasket type and flat-ring gasket types are best used for flat-face flanges and raised face flanges, respectively.
What’s more, the cheapest form of gasket material is the non-metallic gaskets, and they are also readily available.
Non-metallic Materials Used in Gasket Construction
Some types of non-metallic materials used in gasket construction:
- PTFE
- Mica
- Teflon
- Rubber
- Silicone
- Graphite
- Cellulose
- Fiberglass
- Ceramic fiber
Here’s a quick rundown of some of these materials:
- Mica: It is suitable for high-temperature applications since it has excellent temperature resistance.
- Teflon or PTFE: Teflon also has excellent chemical resistance, which has made it a reputable sealant in chemical industries.
- Rubber: Rubber comes with good compression properties, and there are cases where synthetic rubber can withstand extreme weather conditions.
- Fiberglass: Glass is a combination of metal silicates. It has good strength, temperature resistance, and chemical resistance.
- Cellulose: This material is suitable for use in low to medium pressure and temperature applications.
- Ethylene propylene: It is suitable for use in applications that involve corrosive and hydraulic fluids.
3. Composite Gaskets:
Composite gaskets are from a combination of metallic and non-metallic materials. The metallic part offers strength and resilience, while the non-metallic part provides conformability and sealability.
Some examples of composite gaskets include cam profile gasket, metal jacketed, as well as spiral wound gaskets. This material is popular with raised face, male-female, and tongue-and-groove flanges.
Likewise, it is worth noting that composite gaskets are available for a wide range of operating conditions, including high temperature and pressure applications. What’s more, they are inexpensive in comparison to metallic gaskets. There must be a lot of care when handling them.
Gasket Configurations
Some gasket configurations you’ll find include:
1. Full Face:
These are gaskets that cover all the flange faces and the gasket material includes bolt holes. However, there are less uses than full face flanges.
2. Inner Bolt Circle (IBC):
These are gaskets use raised face flanges. The RF flange allows more pressure to be concentrated on the smaller gasket area, and what this does is to increase the pressure containment capability of the joint.
3. RTJ:
These are metal ring type joint gaskets.
Choosing the Gasket Material Based on the Application
Each material has different applications irrespective of whether they are metallic, non-metallic, or composite.
Asides from these, there should be a consideration of certain factors such as the presence of chemicals, extreme heat or cold, abrasive materials, etc. Also, the chosen material must align with temperature and pressure conditions.
Conclusion
There are several types of material to choose from when it comes to gaskets, and your ability to select the right gasket can bring about joint integrity.
In the same vein, there must be considerations of the flange finish to ensure that it is not scratched or dented to minimize the risk of leakage. It all boils down to your ability to select the right material for an application depending on the properties you expect.
Some of these properties include chemical resistance, temperature resistance, relaxation, flexibility, friction, strength, & compression properties. Do you need more information about which gasket material is right for you? Contact us today.