Spiral wound gaskets are basically (semi) metallic rings that are placed between two surfaces that are of different materials with the goal of preventing the leakage. It consists of two parts: a metal wound and the filler material, where the metal part acts as the strong structural support and the filler material is actually the sealing part.
Stainless steel, or carbon-rich metals are used for creating these, while the filler material is usually graphite. One of the best companies, www.specialistsealingproducts.co.uk, is specialized in creating and selling these for various purposes and we asked them a couple of questions regarding these.
How are spiral wound gaskets made?
The process of creating starts with the winding the tracks of metal and filler material over a smaller ring that is made of steel. The metal material is always used for the structure while the material for sealing is picked upon the role of the whole element/gasket.
The process of selection of the sealing material depends on temperature, amount of fluid, chemical reactions between materials. These variables influence the overall selection so the gasket could be used in a certain industry or for certain actions.
The alternating spirals of metal and the filler material are made into the ring made of steel, which has a certain thickness that depends on the purpose of the element.
The outer ring is usually made of stainless steel, type 304 or 321 while the filler material is made of graphite or asbestos. The outer ring, however, is made of carbon steel to ensure robustness and firm structure.
Where do we use spiral wound gaskets?
We use these wherever we have an operating under the high/low temperature and high/low pressure. They are placed in face flanges, as well as in tongue and grow flanges. Wherever we have the two separate parts that are working in extreme environment (high/low temperature/pressure), these are applied as the security for leakage prevention.
Petrochemical industry, as well as any kind of plants, uses this element to prevent any leakage of toxic fluids or elements that could affect the people’s health and inflict serious damage. Oil refinery uses the gaskets to secure two pipes for example and prevent the possible oil leakage.
Also, the high-pressure conditions and environment could have a lot of benefit from using these as they can withstand a really high level of pressure without cracking or releasing.
Can we re-use spiral wound gaskets?
Technically we can re-use them after they had served a purpose for a while, but it is not really recommended thing to do. Over time, high temperature, high pressure and huge amounts of liquids may ruin the overall structure of this element and it is very likely that it will not withstand the same conditions later.
Therefore, the professionals must examine the piping system, take into consideration the operating conditions and fluids in order to determine whether the replacement is needed.
Still, have in mind that these can work for a long time, but once you disassemble them, you must replace these with the new ones.