High Performance Seals for extreme service conditions.

HTMS resilient Metal Seals are designed and produced to provide the required tightness, when subjected to extremes of temperatures, pressure and media.

HTMS metal seals are produced from stainless steel or high temperature alloy tubing, strip and wire.

Development and Engineering of new products is conducted in close cooperation with universities.

In house testing equipment facilitates real hardware testing and comparison with FEA results.

The Oysterseal® in this catalogue is one of the results of this bespoken cooperation.

The sealing performance of resilient Metal Seals is based on a the relative high specific contact load at the sealing line and a certain resiliency or spring back of the elastic metal seal.

The seating load and the corresponding sealing line width, are a function of the selected seal type, cross section, material, material thickness and the alloy properties itself.

Depending on the required tightness and the media to be sealed, a specific seating load will be required. Plating or coating with soft, ductile material will provide better sealing by filling up groove imperfections. The seating load will make the ductile layer to flow and fill up the groove surface irregularities.

Resilient Metal Seals require a controlled compression. Typically these seals are installed in a machined groove, or the compression is limited by a so called retainer plate.

• Sizes: Diameters from 5 mm to 7 meter.

• Cross section from 0,8 mm to 12,5 mm.

• Temperature: Cryogenic to +750°C.

• Pressure: From ultra high vacuum to +500 MPa.

• Available in circular, race track, oval and other shapes.

• Excellent resistance to corrosion and radiation.

• Maintains elasticity or spring back over an extended service life.

• Does not suffer from explosive decompression.

• Capable of reaching tightness better than 10–9 mbar.l/s.

• Radiation resistant.

Resilient Metal seals often have to perform under extreme service conditions. Standard solutions as found in this catalogue may not always suffi ce this requirements.

HTMS can alter the standard design and materials to optimize seal performance for a given application.

With high accuracy and backed by FEA in cooperation with the University, HTMS can adjust the seals cross section, wall thickness, selected alloys, to name a few, in order to adapt seal performance to the variables in service.

In house platings or coatings are applied to improve the sealing performance of metal seals. Depending on the
required tightness, the selected seal, the media to be sealed and the condition of the mating surface, a softer or harder plating or coating shall be chosen. When temperature allows, either PTFE coating or soft silver should be applied.

The soft layer, flows at seal compression into the mating surface irregularities and creates hereby the best seal performance possible.

PTFE coating can achieve leak rates around 10–6 mbar.l/s, measured with the vacuum method.

Metal type plating, like silver, indium, and tin to name a few, can achieve leak rates better than 10–9 mbar.l/s up to 10-12 mbar.l/s.

Also visit www.plating.be for further details.

HTMS recommends to heat treat all non spring energised Metal C Rings. High performance HTMS metal seals will perform better in the heat treated condition.

Heat treatment of super alloys such as Inconel X750, Inconel 718, Haynes 214, will increase the yield strength of the material. This influences directly the seal performances, because of increasing seating load and a better spring back.

The increased seating load will press the soft plating better into the surface irregularities, thereby creating a better seal.

The higher spring back means that the intimate contact between the seal and the mating surface is maintained longer in case of flange deflection. Such flange deflection can be a result of high temperatures, high pressures and/or a combination thereof.

Heat treatment is mostly not required for Spring Energised C Rings and Metal O Rings. However some demanding applications in Oil and Gas evironment do require heat treatment to prevent material embrittlement. (Heat treatment according to Nace)

Annealing and heat treatment also improves the seal’s resistance against fatigue under cyclic loads. Structural integrity will be maintained for an extended period of time. HTMS offers age hardening, annealing and solution and precipitation heat treatment.

Metal O-Rings and and some Spring Energized C-Rings made from austenitic stainless steels, are not precipitation hardenable. These seals can only be supplied in the work hardened condition. For demanding applications and for temperatures above 400°C, HTMS advises to use high alloy steels only.

Heat treatment codes for Jacket and Spring materials

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Resilient metal seals from High Tech Metal Seals NV are used in the most extreme environmental conditions. Spring Energised Metal C Rings are used under extreme conditions where temperature can range from cryogenic up to extreme high temperatures, such as 800°C.
To serve the harsh conditions in today’s Oil and Gas exploration, High Tech Metal Seals NV designs and manufactures resilient metals seals which comply and exceed the ISO 15848 leakage requirements for valves intended for application with volatile air pollutants and hazardous fluids. High Tech Metals Seals are manufactured from high alloy materials so that the finished product complies with NACE MR0175 requirements. Silver plated Metal O rings or Metal C Rings, because of ductile layer are successfully used in high vacuum applications. Silver plated or PTFE coated spring energised C Rings and Metal C Rings comply and exceed the ISO 15848 leakage requirements, from cryogenic temperatures up to extreme high temperatures and pressures. In nuclear applications, particle research, and other radiation application, typically high load resilient metal seals, such as spring energized metal C Rings or Metal O Rings, with a ductile layer of silver are successfully used. High Tech Metal Seals NV, seals for extreme environmental conditions are particularly suited for high pressure. The system pressure assist in maintaining intimate contact with the mating flanges.