How PTFE Seals Are Used

When it comes to materials technology, PTFE must surely be one of the most significant developments of the last hundred years. With one of the lowest coefficients of friction of any known solid material, significant hydrophobic properties and good heat resistance, this fluoropolymer has found uses in an astonishing range of both industrial and consumer products — not least in the form of PTFE seals.

PTFE seals’ material properties make them ideal for use in a variety of moving assemblies, particularly those involving rotary shafts, or reciprocating pistons and rods. The material’s low coefficient of friction often removes the need for lubrication, making this type of seal ideal for dry operating conditions.

The relatively high melting temperature of PTFE means that seals are perfectly suited to conditions with elevated temperatures (to over 200°C) or high thermal stress, and indeed PTFE seals are an ideal high-performance substitute for polyethylene seals where temperature is a factor. PTFE is also extremely chemically non-reactive, and this property leads to the extensive use of these seals in potentially reactive and corrosive environments, including the food, pharmaceutical and chemical industries.

Typical practical applications of PTFE seals include use in:

• Transmission systems and gearboxes
• Rotary or screw-type compressors
• Pumps
• Stirring systems and agitators
• Machine tools
• Mills, crushers and grinders
• Blower systems
• Centrifuge

It’s probably fair to say that these days there are few industries in which seals of this type aren’t utilised.

Examples of the impressive variety of end uses to which PTFE seals can be put include:

• General manufacturing and mechanical engineering, from CNC machines to compressors, vacuum pumps and tank systems.
• Medical and laboratory equipment, including chromatography and endoscopy devices.
• Packaging machines and metering systems in the food production industry.
• Offshore technology, where PTFE seals may be used in petroleum and natural gas processing.
• The aerospace industry, for example in landing gear assemblies.

So how do PTFE seals get to the moon?

Well, they have been much used on the moon and mars rovers for non-lubricated suspension elements and control arms as well as on pumps where their ability to separate the fine granular solids from the working parts in a hard vacuum is invaluable.

Since PTFE was first developed in the late 1930s, the world has seen PTFE seals used in endless applications, from nuclear weapons development (they were used in the Manhattan Project’s uranium enrichment process) to dealing with the high-performance needs of modern racing car engines.

Proof, if any was needed, that its unique material properties makes the humble PTFE seal an amazingly versatile component.