metal ring
- December 31, 2020
Failure is not an option in the most demanding sealing applications. Valves continually strain the capabilities of sealing solutions, and elastomer solutions are often not enough. The unparalleled reliability of high-performance metallic seals from our partners at Technetics can help excel in the face of these challenging scenarios.
In these extreme environments, high-performance metallic seals combine state-of-the-art engineering with advanced materials design to deliver a product that exceeds expectations and stands up to the rigors of these applications.
Why Use High-Performance Metallic Seals?
Traditional sealing methods, such as elastomers or graphite seals, present limitations when extreme environments come into play. Under the tremendous workload of valves in these applications, they can lose tightness or deform, presenting distinct challenges.
- September 29, 2020
In a typical oil refinery or chemical processing plant, 60% of fugitive emissions are attributable to leaking valves. Of these, nearly 80% are released at valve stems. Also contributing to valve failures, are leaks at the bonnet, flanges and seats. As operating conditions in these and other industries continue to subject valves to ever more extreme temperatures and pressures, sealing them effectively poses a challenge that cannot be met with traditional materials and methods. Soft, compressible elastomers provide good sealing performance, but they are porous and cannot withstand temperatures in excess of 482°F (250°C). They also become hard and brittle in cryogenic service. Metal seals have much greater temperature capabilities, high mechanical properties, lack of porosity and long shelf life. Ductility and elasticity are typically the limiting factors.
Today more resilient, metal-to-metal seals are available and being used in valves operating under extreme conditions. Spring- and pressure-energized metal seals function much like a gasket between two flanges with little or no relative motion between them.
C-Ring Metal Seals The sealing principle of spring-energized seals is based on plastic deformation of a jacket that is more ductile than the mating surface. This deformation occurs between the sealing face and an elastic core composed of a closely wound helical spring. The spring provides specific resistance to compression, during which the resulting pressure forces the jacket to yield and fill flange imperfections. Each coil of the helical spring acts independently, allowing the seal to conform to any surface irregularities. This combination of elasticity and plasticity provides an extremely effective seal even under the decompression cycles.