Silicone as a Sealing Material
Wherever liquids and gasses are encountered in machinery and construction, mechanical seals are required. Jehbco produces custom silicone mechanical seals for a variety of applications. Mechanical seals prevent fluids (liquids and gasses) entering between two parts, and they are essential for many man-made things: fuel systems in cars, roofing on houses, taps, fridge door seals – the list goes on!
Many sealing systems incorporate a soft, flexible part that, when placed under load, deforms slightly to fill the gaps and irregularities between two hard parts. These parts generally fall in two categories:
Gaskets: a general term used for a part that is pressed between two harder parts. The part may have any shape, although flat gaskets are common. An everyday example is the door seal in a fridge.
O-rings: these are a special type of gasket that are circular and have a round profile (like a doughnut). O-rings are designed to fit into a groove in one of the parts and are very common in machinery.
Gasket materials must withstand the environment they are to be used in, the fluids they are to seal and the mechanical wear and tear of the application.
Silicone has a range of properties that makes it ideal for many sealing applications:
Temperature range: silicone is able to operate over a very wide range of temperatures, from -50°C to 230°C.
Chemical resistance: silicone is resistant to a wide range of chemicals: engine oil, animal and vegetable oils, brake fluid, fresh and salt water, flame resistant insulators and ozone. Silicone is not compatible with hydrocarbon fuels, acids or alkalis.
Durability: silicone is UV resistant and exhibits extremely good weathering characteristics.
Low swelling: silicone exhibits a low level of swelling – when exposed to a variety of chemicals, the increase in volume of the silicone seal is low.
The one downside of silicone is its relatively poor resistance to abrasion and tearing. However, silicone makes an excellent choice for seals in static applications, where the seal will not be continually rubbed or abraded.
Jehbco has produced silicone gaskets for a range of static sealing applications, including light aircraft door seals, where a large temperature range is required; marine door and window seals, where excellent weathering resistance is required; drinking water, food and medical gaskets, requiring excellent chemical resistance; gaskets for electrical enclosures; and o-rings for salt water piping, to name only a few of our applications! For any help with your application please review the Jehbco website www.Jehbco.com.au, and contact us with any questions.