Donit Tesnit Grafilit Flexible Graphite Sealing Materials

Donit Tesnit Grafilit

Donit Tesnit Grafilit Flexible Graphite Sealing Materials

Graphite itself or laminated with flat / tanged stainless steel insertion is used as a temperature and chemical resistant gasket in chemical, petrochemical and many other industries.

Production Process

The raw material used in the production of Flexible graphite sheets is natural graphite. Natural graphite is a mineral and is mined in a similar way to coal in open-pit and underground mines. Major deposits are in China, India, South America. The crude ore must first be separated. Graphite flakes are enriched, usually by using flotation processes.

Graphite is then heat treated in the presence of strong acids to form intercalation compounds, which are starting materials for the production of expanded graphite particles. After several heating processes intercalation compounds expand more than 100 times. Wormlike structure is produced, which can be easily compressed into flexible foil or sheets without use of binder.

Properties of Flexible graphite

Flexible graphite based gasket has some superior properties to an organic fibres based sealing material. There is no health hazard, material is produced without any binder, fibres or fillers. Therefore it has found also many applications in foodstuff and potable water gasketing.

Flexible graphite is incombustible. It retains surface pressure even in case of ignition of media which it seals. Flexible graphite gaskets can be used from low temperature (-200°C) to elevated temperature of 2500°C. The most important processes for chemical destruction of flexible graphite are oxidizing reactions. It comes to mass losses what leads to those which are not tight. At room temperature is this process practically undetectable.

There is no aging because of absence of binder.Material has practically unlimited storage life. It has very low creep under temperature or pressure.

Flexible graphite is resistant to almost all media. It is suitable to confine steam as well as inorganic and organic bases, solvents, oils and fuels. Exceptions are strong oxidizing media such as highly concentrated nitric or sulphuric acid or molten salts.

Because of its high compressibility, the conformity to flange surface is superior, what leads to good sealing properties at low bolt loading, even when flanges are damaged, distorted or corroded.

Product List: Donit Tesnit Grafilit SF / Donit Tesnit Grafilit SL / Donit Tesnit Grafilit SP

 

Donit Tesnit GrafilitDonit Tesnit Grafilit SF

Properties and application.

Donit Tesnit Grafilit SF is a gasket material with very low creep relaxation and high tightness at low bolt loading. It is suitable for almost all chemicals, in food industry and in contact with drinking water. Because of the high compressibility of Donit Tesnit Grafilit SF, it is suitable for glass or enamel flanges.

 

Donit Tesnit GrafilitDonit Tesnit Grafilit SL

Properties and application.

Donit Tesnit Grafilit SL is a gasket material with excellent strength and creep resistance, chemical stability and a high tightness rate. Because of a stainless-steel insertion it is easier for handling and installation compared to the non-reinforced. Donit Tesnit Grafilit SL is suitable for wide range of applications especially for higher operating pressures like in gas supply.

 

Donit Tesnit GrafilitDonit Tesnit Grafilit SP

Properties and application.

Donit Tesnit Grafilit SP is a gasket material which combines excellent properties of expanded graphite and the strength of stainless steel. This type of material features has very good strength and creep resistance, chemical stability and high tightness. Donit Tesnit Grafilit SP is used in the chemical and petrochemical industry, at high surface loads or high operating pressures.

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