Flat gaskets from thoenes ®
Flat gaskets are primarily used in the chemical industry, the sanitary sector, and the food and pharmaceutical industries. Their function is to seal stationary and flat surfaces. The term ‘flange gaskets’ is used when static gaskets are employed as sealing elements between two flanges connected by bolts. This is the case in pipework construction, for example, where the connected pipes contain a specific medium that must not leak. The flat gasket, as a sealing element, prevents precisely that. Furthermore, it is also useful in a wide variety of components such as valves, pumps or fittings.
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Properties of flat gaskets
Flat gaskets are a type of static seal and are pressed into place purely by external forces; this makes them quick and easy to install and also quick to remove. They not only provide a seal but also compensate for unevenness in the flanges. Please note, however, that the gaskets do not automatically adapt to the pressure to be sealed; they are therefore not pressure-activated. Extremely flexible, low-wear and resilient, these gaskets are particularly suitable for sealing solvents, gases, fuels and oils.
Flat gaskets made from various materials
As flat gaskets are required for different applications, they are therefore available in many different materials. It is important that the material withstands the conditions in which the gasket is used. These include, for example, high temperatures or high pressure: both pressure and vacuum, as well as sudden and significant increases in pressure, have a significant impact on the flat gasket. This occurs particularly when closing valves and when liquids are heated rapidly, causing them to expand. A well-known example of this is steam shock. Large temperature differences also have an impact: for instance
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the material may harden due to high thermal stress.
The mixture or medium with which the seal comes into contact is also crucial for selecting the right material. Is it gaseous or liquid? Is it a pure mixture, which is rarely the case, or does it contain various components that in turn have different effects? To ensure you select a flat gasket made from the correct material, you should know exactly in advance which factors will be at play and, ideally, test this in a laboratory, particularly when aggressive mixtures are to be transported.
Thoenes-Solutions offers flat gaskets made from a variety of materials. In our range of fibre boards, for example, the thoenes ® BA 110 material is available, which consists of aramid fibres and NBR. This gasket has high chemical resistance and is suitable for higher mechanical stress. It can therefore withstand moderate loads in industrial plants for gases or foodstuffs, as well as in the chemical industry. The thoenes ® BA 120 flat gasket material is also made from aramid fibres and NBR. Thanks to its pressure resistance and chemical resistance, which result from the material’s composition, it is primarily used in drinking water supply systems and the food industry. thoenes ® DO 181 is a high-performance sealing material for gaskets that impresses with its excellent resilience, chemical resistance and outstanding sealing performance even at high temperatures. You can therefore use it for flanges, valves, compressors or heat exchangers in power stations or heating systems. For steam, fuels, lubricants, alkalis and mild acids, we recommend the BA-F flat gasket material. It consists of synthetic and mineral fibres. It is also mixed with graphite to create a high-temperature-resistant material and bound with NBR elastomers. You can therefore use it in industrial applications or with air, gases or liquids.
Flat gaskets are also available from Thoenes-Solutions in the form of graphite sheets. These are made of expanded graphite. Thanks to their outstanding chemical, thermal and mechanical properties, they are suitable for use at high temperatures and under cyclic thermal pressures or pressure loads. The differences between the various graphite sheets lie in the metal inserts: the thoenes ® SP TRD 401 has a metal insert made of corrugated sheet metal, whilst that of the thoenes ® SL graphite sheet is made of smooth sheet metal. The thoenes ® SF flat gasket material, on the other hand, has no metal insert.
The thoenes ® ePTFE flat sealing tape and the seals made of PTFE (polytetrafluoroethylene) are also available in FDA-grade quality on request. The PTFE tape is suitable for both right-hand and left-hand threads. Thanks to their exceptional temperature resistance ranging from -268 °C to 270 °C, depending on the application, they can be used universally. The sealing material consists either of 100% multidirectionally expanded PTFE or 100% pure, monodirectionally expanded PTFE.
Seals made from rubber materials are not uncommon. The thoenes ® EPDM flat sealing material is suitable for continuous use at 70–100 °C. Further seals are available from Thoenes-Solutions, including the thoenes ® NBR/SBR material, which is suitable for a temperature range of 90 to 100 °C, and the red thoenes ® silicone flat sealing material, for continuous use at 250 °C. These seals are also resistant to ozone weathering and are highly elastic.
Custom-made flat seals
Thoenes ® offers not only standard sizes but also the option to manufacture custom flat seals to your specifications. Whether for specialised applications in the chemical, food or pharmaceutical industries, or for sealing in unique technical designs – we can provide you with exactly the seal you need. Our bespoke gaskets are manufactured exactly to your specifications, taking all relevant criteria into account to ensure the highest precision and efficiency. You can specify the material, dimensions, thickness and shape. Whether you need a simple round gasket, complex geometries or a custom-made product based on your drawings – we offer the right solution for your requirements. Thanks to state-of-the-art manufacturing techniques, we guarantee the highest precision and quality, even with the tightest tolerances. Contact us for custom-made flat gaskets – we will be happy to advise you on selecting the right material and the optimal manufacturing method.
Flat gaskets in the online shop
The range from thoenes ® includes various sizes, thicknesses and sheet formats. The flat gaskets are manufactured to dimensions, in accordance with DIN EN 1514-1, DIN 2690 or to drawings. We can then issue a factory certificate for you. Generally, our gaskets are primarily used in flanges, valves, pumps, heat exchangers and tank systems. Depending on the material, our gaskets are resistant to pressures of approx. 5–160 bar. If you require flat gaskets with particularly high temperature resistance up to a maximum of 1000 °C, the thoenes ® Glimmer SW-Temp C90 or the thoenes ® Glimmer SW-Temp STS (with perforated sheet insert) gasket sheet material is the right choice for you.
In addition to flat gaskets, we also offer other products, such as fabric gland packings and sealing and insulating cords. Take a look at our comprehensive product range. Do you have any questions about our range, how our products work, or the right flat gasket material for your specific application? Then please feel free to contact us.