How to Solve Large-Size Sealing Challenges at Temperatures up to 800 °C
When classic sealing materials – for instance in temperature ranges above 300°C and below -50°C – reach their limits alternative materials are required such as metal with appropriate coating/plating.
Parker offers metal seals made of stainless steel or nickel alloys in C, E and other designs characterized by high pre-loading force and significant resilience. Drawing on many years of experience in the gas turbine market, Parker has continually expanded its expertise in large diameters and developed special problem solutions that substantially increase the efficiency of the machines.
Metal seal types and sizes
The most important manufacturing technologies used to produce metal seals from stainless steel or nickel alloys are rolling, forming, CNC machining, welding, heat treatment and coating/plating. In its more than 60-year history of producing metal seals, Parker has continually tackled the challenge of manufacturing increasingly large metal seals. Currently, spring-energized C-rings with a diameter of up to 7.6 m can be produced for which special forming machines and patented welding techniques were developed. They are supported by optimized special heat treatment and electroplating processes that make it possible to manufacture high-quality products even in such large dimensions. Additionally, Parker offers non-rotationally symmetric metal seals. These E-, O- and C-seals can be produced in lengths of up to 2.3 m on machines specifically developed for this purpose.
- C-seals: ≤ 3,000 mm
- Spring-energized C-seals: ≤ 7,600 mm
- O-rings: ≤ 1,200 mm
- Heat-treated ≤ 2,700 mm
- Segmented ≤ 7,600 mm
Materials and coatings
The base materials used are special nickel alloys that withstand temperatures of more than 800 °C. These cobalt-nickel-chromium-tungsten alloys or heat-treatable nickel super-alloys make high demands on the welding technology used and are reliably processed at Parker due to optimized manufacturing processes and comprehensive suitability tests.
The choice of plating is primarily focused on wear protection, corrosion resistance and improvement of the sealing properties. For this purpose, the surface properties of the metal seal are modified and a formable external surface layer with adjusted hardness is created. Parker’s application engineering team will advise you in making the appropriate selection from the available plating range of gold, silver, nickel or TriCom® coating.
- Power Generation – Sealing Solutions for Gas Turbines
- Chemical Processing – Sealing Solutions for Heat Exchangers
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Article contributed by
Thorsten Kleinert, business unit manager composite sealing systems
Engineered Materials Group Europe, Prädifa Technology Division