Metal bellow seals are essential components used in a variety of mechanical systems. They are primarily used in rotary and reciprocating applications to maintain the integrity of the process medium and system pressure. In comparison to other sealing methods, such as O-rings and piston rings, metal bellows provide superior performance and reliability.
A metal bellow is a metal cylinder with an accordion shape, with an opening on one end. Depending on the specific application, the cylinder may be composed of a variety of corrosion-resistant metals, such as stainless steel, Inconel, Hastelloy, and titanium. It has a flexible wall, which makes it inherently self-adjusting, providing the ability to compensate for any lateral, angular, or axial misalignment between the two surfaces.
Metal bellow seals offer several advantages over other sealing methods. For instance, they can withstand higher temperatures due to their low thermal expansion rate and wide range of temperature operation. They have a low leakage rate and can maintain tight sealing performance throughout the entire process. Additionally, they are suitable for corrosive or abrasive media, do not require lubrication, and are relatively low-maintenance and cost-efficient.
Despite the several advantages of metal bellow seals, there are some limitations. Due to their flexible design, they are not suitable for high-pressure or leak-tight applications, meaning they should be used in low-pressure systems or as a secondary seal. Installation also requires a great deal of experience and skill to ensure proper alignment and that the bellow is correctly tensioned.
In conclusion, metal bellow seals offer a wide range of advantages for both rotary and reciprocating applications and are suitable for a variety of media and temperatures. Despite the several limitations, such as their unsuitable for tight- seals and complex installation requirements, metal bellow seals are the preferred solution for many mechanical applications, due to their superior performance and reliability.
