by Jenny Knodell, IQS Editor
Space ships and refrigerators really aren’t so different. Sure, one is used in every home to keep perishables cold and the other is a vessel that costs millions and millions of dollars for outer space exploration, but without gaskets, both would break down almost immediately. There would be rotten food and astronaut casualties everywhere. Now that you know how important they are, you might be surprised at how simple they are—gaskets are merely round, flexible little rings with a flat profile, essentially used to create a mechanical seal by filling the space between 2 objects. They prevent liquid and gas leaks while under pressure, maintain proper part spacing and dampen vibration. They’ve been used for a better half of a century, and are made of many different flexible materials, including rubber, silicone, Teflon and plastic.
Perhaps the most recognizable gasket is the o-ring, which exhibits a few slight differences to the standard gasket. An o-ring is always circular with a circular profile, and is used in simple, static sealing applications. While they provide a very strong seal, they are limited to circular flanges which limit their applications quite a bit. Gaskets aren’t always round and are usually flat on both sides, but have a much wider range of shapes to choose from. Ever heard of the phrase don’t blow a gasket, meaning don’t lose your temper? This phrase is directly referencing a head gasket, which is an important component of automobile construction. They are small, usually made of metal coated in heat-resistant material like Teflon, and used to seal cylinders between an engine block and the internal combustion engine. When the engine overheats, a gasket could blow, resulting in extensive and severe engine damage.
Image courtesy of Reliant Rubber Company.
While gaskets are extremely important components to many different mechanical products and machinery, they also cause a lot of problems. Some tend to harden and shrink if exposed to low temperatures, like the o-rings in the Challenger disaster, which resulted in a catastrophic space ship take-off, while others wear out quickly and need constant replacement. They are used in extremely stressful environments, and are expected to function in a broad range of temperatures, under high pressure and exposed to constant vibration; it’s no wonder they wear out quickly. This causes frequent maintenance and replacement, which cause high labor costs, machine down time and process interruption. But since gaskets are an important and integral part of so many machines, what other choice is there?
Image courtesy of Premier Seals Manufacturing.
Well, very recently, gaskets made of flexible graphite coated in stainless steel have been employed to replace old, standard materials. They last much longer than rubber or plastic, and may be exposed to a broad range of temperatures without changing shape or flexibility. They are safer and able to seal uneven surfaces with ease. Stainless steel-coated graphite gaskets cost similar to spiral wound gaskets, which are similar in construction to these new gaskets, but the metal and flexible filler material are wound together. So while graphite gaskets tend to cost a bit more than the standard type, their benefits over time will save money on labor and maintenance.
Stainless steel coated graphite gaskets.