Seals are central parts of the design of medical equipment with moveable, interlocking parts that must be secured for sanitary, thermal, or radioactive reasons.
Designing with inflatable seals requires the inclusion of a source of compressed gas, which is used to inflate seals in the medical device industry and it is often already available on the plant floor, in a laboratory, or medical environment. It is also possible to inflate with liquids rather than gas in demanding applications, and water would be an acceptable inflation media in this sector, although not common. For some low-temperature applications, a seal may be inflated with a blend of glycerine and water.
Seals used on doors and openings should be part of the early phases of product design. In some cases, contact seals may be effective, but they often require substantial force be applied to load the seal, which impacts product design and increases manufacturing cost. Inflatable seals enable more cost-effective machinery fabrication for two reasons:
A metal seal is used when the application conditions are outside the specification limits of a polymer; extreme heat, extreme cold, extreme pressure, or a vacuum. With significant resilience coupled with the right material selection/coating for an application, a metal seal can be a very durable seal performing dependably year after year.
O-FLEX™ metal O-rings are designed to provide a sealing option for high-pressure/high-temperature applications that require minimal spring back. The O-FLEX™ metal O-ring is made from high strength metal tubing that is coiled, cut and welded to size. It is available in standard cross-section increments of 1/32”. The O-FLEX™ metal O-ring seating load can be adjusted to the application by varying the cross-section and tubing
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.
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.
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.
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.
Spring-energized metal seals provide numerous advantages in oil and gas applications, including but not limited to MWD and LWD tools, couplings, subsea compressors, enclosures/vessels, christmas trees, electronic submersible pumps and flowmeters. Extreme operating pressures and temperatures, together with more difficult resource recovery, zero tolerance for failure and environmental concerns, are placing unprecedented demands on this equipment.
Traditionally this industry has used solid machined seals that provide high compression loads but lack resilience. They also tend to have relatively high rates of leakage over time as flanges deteriorate. Recent advances in metal seal technology provide controlled compression, high resilience and reduced leakage.
The Aasgard oil and gas field in the North Sea has been operating since 1999. Innovative subsea processing technologies were used to compress the oil and gas on the site’s seabed to improve recovery rates as the field ages and as equipment begins to draw from increasingly deeper subsea reservoirs. The operator required seals for the lid and body of the control power distribution unit in order to protect its vital electronics in the harsh, unforgiving subsea environment.
As a globally trusted source for engineered components, seals, assemblies, and sub-systems for demanding environments, Technetics was uniquely positioned to evaluate and specify a sealing solution for this application. The system designer and Technetics engineers subsequently underwent a two-year testing phase to examine the performance of a variety of sealing options.
Due to the extremely demanding environment in