While they are low cost and appear to be simple, the value of choosing the best gasket material — such as expanded ptfe, vegetable fiber, or flexible graphite —cannot be understated. Even so, the custom gasket material is often not reviewed until there is gasket failure or if there is a high maintenance cost associated with servicing the gasket.
In either case, the primary function of a custom gasket is to provide mechanical seals for a liquid or gas throughout the life of the application. The industrial gasket serves as a buffer and compensates for any imperfections between mating surfaces that need to be sealed.
Let's take a closer look at a few elements that should be addressed in choosing the best gasket material for mechanical seals and other applications.
The starting point for choosing the best gasket material is typically temperature. Temperature considerations are critical because it can alter the physical characteristics of a material, including compression set, sealing properties, and maximum allowable stress.
It's vital to consider both external and internal temperatures because gaskets in direct sunlight exposure can easily experience internal temperatures in excess of 140 degrees.
On the other hand, exposure to an extremely cold flow or freezing temperatures can cause gaskets to become brittle or stiff, which can alter their physical properties and increase the chances of it failing.
Gaskets that experience cycling from warm to cold or vice versa in extreme applications can exhibit a higher compression set. As you can see, considering the temperature range is critical in choosing the best gaskets. It's imperative the material selected for gaskets can withstand exposure to the necessary range of temperatures.
Ozone and UV exposure are both potential sources of rubber gasket degradation. It's also important to understand ozone doesn't just come from the atmosphere, but it can be created by electrical enclosures with high voltage electrical components.
In either case, ozone and UV will break down the carbon bonds in the backbone polymers, which can result in hardening, drying, flaking, cracking, and scaling. Organic rubber gaskets like natural rubber, Buna-N (Nitrile), Buna-S(SBR), and synthetic isoprene will break down relatively quickly in exposure. However, EPDM and silicone are two materials that may be better equipped to resist UV in different applications.
When a certain amount of pressure is exerted on a system, joints can begin to deform. As a result, it's vital for pressure to be considered when choosing the best gasket materials. Today, some of the gaskets have a P x T rating factor offering insight into the max limits of pressure and temperature combined.
Manufacturers of aerospace, automotive, consumer, and industrial electronics are required to meet Federal (EMI) product standards. EMI is emitted by components as well as internal wires and can function like emitting antennas.
For EMI radiation to be controlled, electronic components must be completely encased in a conductive enclosure, and it's vital the enclosure and lid have complete contact.
As a result, a viable conductive gasket is necessary. In addition to EMI attenuation, these gaskets may also function as environmental sealing.
Undoubtedly, the media the gasket will be exposed to is a critical consideration. In general, gas will be more difficult to seal than a liquid. After the material with an acceptable temperature/pressure range has been identified, the next step is to consider whether it will be compatible with the media being sealed.
Chemicals can impact the functional properties and structural integrity of the material. And the chemical resistance of the gasket material is critical because the other properties of the gasket material would be irrelevant.
You should also consider the effect temperature will have on its chemical resistance. For instance, many fluids can be more aggressive in certain temperatures. As a result, gaskets used to seal fluids at an ambient temperature may not perform the same at higher temperatures.
Now we've covered a few of the top considerations for choosing the best gasket materials, let's look at a few common materials and their characteristics. At Frank Lowe, we offer most of our gasket materials on a roll or on a sheet based on the unique needs of your application.
Non-asbestos types of gaskets are created from a compressed fiber material and a binding elastomer. Non-asbestos types of gaskets are used across many different applications, involving water, oil, acid, and steam.
Cork gasket materials are very stable, lightweight materials with the ability to resist water penetration.
It boasts outstanding compressibility, high resistance to oil, solvents, and no lateral flow. Cork is unaffected by extreme temperatures and is resistant to wear. At Frank Lowe, we offer cork materials on a sheet as well as on rolls.
Cork-n-rubber materials are a combination of synthetic rubber polymers and granulated cork.
This offers high flexibility and resilience of rubber with the compressibility of cork. In addition, the rubber boasts the ability to provide chemical compatibility and act as a seal while helping resist weather conditions, acids, and fungus.
You can choose from a range of different rubber materials to best meet the chemical resistance needs of the gasket. You can also opt for cork-n-rubber die cut on a sheet or on a roll based on your needs.
Silicone gaskets are offered as foam, sponge, or as a solid. In either case, the characteristics can include general inertness, high-temperature stability, and resilience.
Silicone offers a number of benefits, including: