FS - Fox Float '24+ Damper Service Kit - Low Friction FKM

FKM Seals: Overview

FKM (Fluoroelastomer) seals are made from fluorocarbon-based synthetic rubber, known for their outstanding chemical, thermal, and mechanical properties. Commonly referred to by brand names such as Viton® (a trademark of Chemours), FKM is widely used in demanding applications, especially in chemical processing, automotive, aerospace, and oil and gas industries.

FKM seals are particularly suited for both static and dynamic applications where exposure to extreme temperatures, aggressive chemicals, or high-pressure environments is expected.

Benefits of Dynamic FKM Seals

1. Excellent Chemical Resistance
   FKM seals are resistant to a broad spectrum of chemicals, including fuels, oils, hydraulic fluids, and solvents. This makes them ideal for dynamic applications in harsh chemical environments.

2. High-Temperature Resistance
   FKM seals can operate effectively in temperatures ranging from -20°C to 230°C (-4°F to 446°F), with some specialized grades tolerating even higher temperatures. This is a major advantage in applications involving high heat.

3. Outstanding Compression Set Resistance
   FKM seals maintain their shape and sealing properties under prolonged compression, which is critical for dynamic applications requiring consistent performance over time.

4. Resistance to Ozone and Weathering
   FKM materials are highly resistant to UV light, ozone, and weathering, ensuring long-term reliability in outdoor or exposed environments.

5. Low Permeability
   FKM has low gas permeability, making it an excellent choice for sealing gases or preventing fluid leaks under high-pressure conditions.

6. Good Mechanical Properties
   FKM offers strong tensile strength, tear resistance, and durability, which are critical in applications with dynamic motion, such as rotary or reciprocating movement.

7. Compatibility with Diverse Fluids
   FKM is compatible with a wide range of automotive and industrial fluids, including biodiesel, ethanol-blended fuels, and high-temperature lubricants.

Negatives of Dynamic FKM Seals

1. Limited Low-Temperature Performance
   FKM seals lose elasticity and may become brittle at temperatures below -20°C (-4°F). Special low-temperature grades are available but may come with trade-offs in other performance areas.

2. High Cost
   FKM is more expensive than many other elastomers, such as NBR or polyurethane. This makes it less cost-effective for applications where its high-performance characteristics are unnecessary.

3. Moderate Abrasion Resistance
   While durable, FKM seals do not offer the same level of abrasion or wear resistance as polyurethane, making them less suitable for highly abrasive environments.

4. High Friction in Some Applications
   In dynamic motion, FKM seals can generate friction, especially if not properly lubricated, leading to heat buildup and wear.

5. Swelling in Certain Chemicals
   Though resistant to most chemicals, FKM seals can swell or degrade in the presence of certain organic acids, amines, and superheated steam.

6. Specific Installation Challenges
   FKM seals are less flexible than some other elastomers, making installation in tight spaces or over sharp edges more challenging. Care must be taken to avoid tearing.

Applications of Dynamic FKM Seals

• Automotive fuel and oil systems
• Aerospace hydraulic and pneumatic systems
• Oil and gas equipment exposed to high temperatures and chemicals
• Chemical processing plants requiring resistance to aggressive fluids
• Power generation and industrial machinery
• Rotary shaft seals, valve stem seals, and O-rings in dynamic applications

Conclusion

FKM seals are an excellent choice for dynamic applications where chemical resistance, thermal stability, and durability are paramount. However, their limited low-temperature performance, higher cost, and moderate abrasion resistance mean they may not be the best fit for every application. Careful evaluation of operating conditions and material properties is crucial to select the appropriate sealing solution.