For fluid sealing, different kinds of packings are used. Graphite packings and PTFE Packings are popular sealants generally available in braided style. The biggest difference between both these packings is that graphite is a naturally occurring form of carbon and PTFE is a synthetic material. Yarns go through multiple heat treatments to get the shape and structure of the desired characteristics of packings.
Let’s understand PTFE vs Graphite Packings on the basis of the following aspects:
Composition
Graphite is an inorganic form of pure carbon. Graphite packings are black-coloured braided sealants made using pure carbon. They can be blended with other elements or PTFE for enhanced features.
PTFE stands for Polytetrafluoroethylene. It is a white-coloured synthetic polymer made through polymerization of tetrafluoroethylene. PTFE yarns can be lubricated to make flexible packings with better properties.
Properties
High-quality graphite yarns are braided together to form Graphite packings. They have a very low coefficient of friction. Graphite packings can be a conductor of heat. PTFE is a strong resin with low coefficient of friction as well. It is highly resistant to different kinds of substances such as aggressive chemicals, acids, gases etc.
Teflon is a variant of PTFE that is widely used for making non-stick cookware. PTFE prevents wearing of shafts and also works as a very good insulation material for electrical uses.Multi-yarn packings are made using PTFE to get better strength and lubrication capabilities.
Applications
Graphite packings are suitable for use in agitators, valves, and shafts that handle chemicals, acids, etc. They are also used in applications that involve high pressure, greater shaft speed and high temperatures.
Expanded Graphite packings are used in steam turbines and high-temperature valves. PTFE Sheet manufacturers also serve clients dealing with fuel gases, mineral and synthetic oils, steam water, effluents and more.
PTFE packings are used in industrial plants that deal with corrosive substances and oxidizers except for molten alkali metals. PTFE Packings are ideal for most forms of aggressive media. They are utilized in pharmaceutical, food, aerospace, electrical and many other industries.
PTFE envelope gaskets are used in industrial plants for safer handling and management of highly reactive substances.
Benefits
Expanded Graphite packings are perfect alternatives to asbestos packings. Simplified installation and quick maintenance are some of the benefits of graphite packings.
PTFE packings have a longer shelf life due to their lower coefficient of friction. Multi-yarn packings with PTFE can be designed as per FDA requirements to be used for edible products and pharmaceutical products.
Graphite packings can be treated with PTFE to get better benefits such as preventing colour contamination, gaining better stability etc.Both graphite, as well as PTFE packings, are cost-effective as they bothare durable and require low maintenance.
A wide range of fluid sealants is available in the market. Choosing the right packing depends on the pH, temperature and shaft speed required. It is also better to look into the thermal and chemical properties of the braided yarns thatinfluence the properties of the packings.