PTFE O'Ring
PTFE O-ring or Teflon O-ring (DuPont’s brand name) is a mechanical gasket that is a gold standard for high-performance sealing solutions. The O-rings are made from different grades of polytetrafluoroethylene whose main elements are fluorine and carbon.
The Teflon O-rings are suitable for applications requiring non-compressible material while offering the highest thermal and chemical resistance.
Ideally, a Teflon O-ring is a circular-shaped gasket, with a wide hole or space at the center. At times, you may find people calling this sealing accessory PTFE packing. However, the name PTFE toric joint is not common.
Main Characteristics
Wide PTFE O-ring Temperature Range
The working temperature varies between -328°F and 482°F. A good example is cryogenic O-rings. Besides, they have the highest thermal resistance.
Chemically Inert
Virgin PTFE O-rings are resistant to most solvents or chemical agents. A reason you will find the O-rings in most joints in chemical industries. Only a few alkali and fluorine compounds can affect these O-rings but under special conditions.
PTFE O-ring Pressure Rating
The pressure rating varies with the O-ring’s cross-section area. It varies from low to medium.
Teflon O-ring Compressive Properties
The compressive strength is about 3,500 psi with a load-bearing capacity of about 130 and 140 kg/cm2.
Slippery Property
It has the lowest friction coefficient. This makes it a perfect sealing for moving sections.
Different Sizes and Shapes
Looking at PTFE O-ring size chart, you will find many options with varying radial and axial cross-sections. This also affects the internal and external diameters. You can get PTFE large diameter O-ring or small options, depending on the requirements of the application.
Applications
The polytetrafluoroethylene O-rings prevent possible leakages. PTFE O-ring flexibility is a contributing factor to its use in either dynamic or static applications.
- Mass spectrometer probes
- Valve systems
- Common in fluid-carrying systems
- Flange connections
- Milling and grinding systems
- Stirring, mixing, or agitator processes
- Blower systems
- Pump systems
- Caps, etc.
It is worth noting that PTFE O-rings are costly. Also, if you are opting for reusing PTFE O-rings, ensure they are in good working condition. Due to the PTFE non-stick property, the O-rings are easy to clean.
- Specification Sheet
| ID （mm） | Cross Section (mm) |
| 1.8–18mm | －—– |
| 19–69mm | 1.8–2.65mm |
| 71—218mm | 1.8mm 2.65mm 3.55mm |
| 224—670mm | 2.65mm 3.55mm 6.3mm 7.0mm |
Related Products
Many Designs Available
You can find both stand and custom Teflon O-ring designs. For instance, there are:
- Round PTFE O-rings
- Rectangular PTFE O-rigs
- Square cut beveled PTFE O-ring
- Expanded PTFE O-ring
Many Color Options
Although virgin PTFE produces whitish O-rings, you can find other color options depending on your custom requirements.
In addition to these, Teflon O-rings have a long service lifespan, will not swell as a result of absorbing moisture, and offer better electrical insulation.
Among the biggest challenges you may experience with an O-ring made of PTFE are:
- High hardness, which may affect the sealing properties
- Compared to elastomeric O-ring, leakages can be high on PTFE
PTFE O-rings Working Principle
Slide the Teflon on the surface you want to join. In case there is a groove, ensure it fits the groove perfectly.
With the Teflon O-ring between the mating surfaces, you will assemble the two sections. Usually, even when subjected to high compressive force and thermal conditions, the O-ring will expand for better sealing conditions.
