The Basics of PTFE Expansion Joints
Kadant Unaflex offers expansion joints in a full array of configurations and materials. Often rubber, metal, or fabric expansion joints are not able to meet the need of the application. Pharmaceutical, chemical, and FDA food processing plants often have strict guidelines in their fluid handling systems and the surfaces of rubber and metal expansion joints do not meet these standards. To resolve this issue, PTFE is often used.
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer with many applications. PTFE is commonly known by its trademarked name TEFLON®. Teflon is a registered trademark of Chemours, a spin-off of DuPont Inc. Discovered in 1938, PTFE is used in many products and industries for its non-stick properties and inertness to chemical reactions.
Kadant Unaflex produces formed PTFE expansion joints with two, three, and five convolutions. These joints are commonly used in water treatment, pharmaceutical, and chemical facilities. When higher pressure applications are called on, PTFE can be combined with rubber and metal to form PTFE lined expansion joints. PTFE lined rubber expansion share the same performance as standard rubber builds but with the added properties of PTFE that allow for use in food grade and pharmaceutical applications.
Advantages of the PTFE liner in both metal and rubber expansion joints include:
- Increased resistance to chemical interaction
- Non-stick wetted surfaces
- Added protection against spillage
- Corrosion resistance
The PTFE liner serves as a primary skin to the fluid being transferred while the body of the rubber or metal expansion joint serve as a secondary measure to prevent leakage from the joint. The PTFE also gives metal joints added protection against corrosion by keeping the liquid away from the metal convolutions.