Benefits Of A Balanced Interference Fit Bellows Seal Design In High Temperature Corrosive Applications
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Metal bellows seals, originally developed for the aerospace/defense industry, are now widely accepted in the petrochemical, chemical, and general industrial markets. Metal bellows seals offer enhanced dynamic tracking of the seal rings because they eliminate dynamic secondary seals. They are ideally suited for difficult high temperature applications, like those in the petrochemical industry that demand enhanced seal reliability. An effective means of ensuring seal reliability is by controlling face distortion, which directly affects the operating conditions at the sealing surface. When designing a seal, it is necessary to consider distortion resulting from pressure, the presence of temperature gradients in the area of the interface, and stress relaxation of interference fit components. All three of these factors can result in distortion of the face and changes to the lubricating fluid film thickness between the faces. Historically, to reduce stress relaxation of interference fit components in high temperature applications, material selection was limited to materials with a coefficient of thermal expansion similar to that of the seal ring insert. Recently, innovative design and manufacturing technology has made it possible to offer metal bellows seals made of corrosion resistant alloys for high temperature applications (up to 800 degrees F). This design controls face distortion at elevated temperatures. It does this through design rather than material selection, which limits the applicability of the seal. A comparison of the new design to more traditional designs is made and the performance advantages, including experimental and field test results, are described. The combination of an optimized metal bellows and balanced interference fit technologies provide enhanced seal performance for high temperature, corrosive applications.
Casucci, David; McCollough, William J. (1992). Benefits Of A Balanced Interference Fit Bellows Seal Design In High Temperature Corrosive Applications. Turbomachinery Laboratories, Department of Mechanical Engineering, Texas A&M University. Available electronically from