Understanding Spring Energized Teflon Seals: Complete Guide

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by Jackie Johnson

You’ve taken on a new project, and there are components of it that you aren’t sure you’ll be able to seal properly. Odds are if you’re looking for the right seal, this project is a big one that demands the highest quality seals. That’s where spring energized Teflon seals can help. Spring energized seals are often necessary for engineering or other projects. They help to provide reliable, durable sealing solutions.

So, what are Spring Energized Teflon Seals? Spring energized seals are spring energized U-cup seals with various jacket profiles, materials, and spring types in different configurations. They’re utilized when elastomeric seals fail to meet basic requirements. PTFE seals typically have three essential design elements:

  • A pressure-actuated U-shaped jacket
  • A metal spring loading device
  • High-performance polymeric seal materials

Keep reading for a complete guide to spring energized Teflon seals!

Complete Guide to Spring Energized Teflon Seals

Spring energized Teflon seals help provide durable and reliable sealing solutions. Sometimes PTFE seals are solutions for critical applications that are often under extreme operating conditions in different industries. This type of seal design helps:

  • Provide gas-tight sealing systems
  • Achieve fugitive emission reduction goals
  • Meet environmental regulation requirements

A highly effective PTFE spring energized seal is created as the pressure system increases enough to take over from the spring and engage the bore or shaft. The spring or energized seal assembly provides permanent resilience to the seal jacket. This includes compensation for jacket wear, irregularity, and ware misalignment. The jacket material is crucial in design to assure proper seal performance. Jackets are made from high-performance polymers or PTFE.

Spring energized PTFE seals offer extreme cold or heat, high pressure, chemically inert dynamic and static sealing for the most demanding applications. By using a thin PTFE sealing jacket, you are utilizing a spring designed to apply outward pressure to the sealing element at low pressures.

Where Spring Energized Seals Can Be Applied

Spring Energized Teflon SealsYou may be wondering what applications benefit from the use of PTFE seals. PTFE seals are ideal for any hard to seal application, such as those with low or high temperatures, high speeds, high pressures, or extremely corrosive environments. They’re also useful in applications that require low friction. By utilizing various jackets, PTFE seals are designed to meet any demand made on a seal.

When other seals fail to meet chemical resistance, temperature range, or friction requirements, Spring energized seals can be respectively used in these configurations:

  • Rotary
  • Rod and Piston
  • Face Seal

Examples of industries or components where spring energized Teflon seals can be applied include medical or biomedical devices, fluid handling, semiconductor, food service industry, HPLC, oil and gas, compressors, cryogenic, or in dispensing equipment.

Materials

Jacket profiles are made from high-performance polymers or PTFE (Teflon). Spring types of seals are also made in non-corrosive alloys like stainless steel, Hastelloy, and Elgiloy. These jackets are machined but not injection molded, so they can easily be customized when necessary to enhance a seal’s performance. The material of PETF seals is strictly premium-grade across a variety of dimensions.

Spring Types

Spring energized PTFE seals use one of three different spring types when energizing a jacket. You should consider two elements precisely when selecting the proper spring design: its deflection range and load value. The spring’s load value affects it’s sealing ability, wear rate, and friction. The three different spring types include:

  • Cantilever Springs– made from flat metal strips punched or chemically etched into a serpentine pattern. These form into a rounded “v” shape that is available in either a light or medium load spring. This spring type is used for dynamic applications involving rotary motion.
  • Canted Coil Springs– made from round wire coiled and formed into a canted or slanted “c” shape. This creates a radial compression spring with a very flat load. This spring type is intended for rotary and dynamic reciprocating applications.
  • Helical Springs– made from a flat ribbon metal strip stock formed into a helix shape. This spring type is used for static applications. It produces an evenly distributed load across every band with little to no gaps between coils.

Advanced EMC Technologies’ Spring Energized Teflon PTFE Seals

We offer high-quality spring energized PTFE seals for applications with extreme pressure and temperature, dynamic sealing, and chemically inert static. Our seals have thin, flexible PTFE sealing jackets that utilize the spring design to apply outward pressure to the sealing element at low pressures. Our PTFE options include:

  • High PV Seals
  • Cryogenic Seals
  • High-Temperature Seals
  • PFTE Seal Alloys with fillers including:
    • PTFE Graphite
    • PTFE Polymide
    • PTFE Carbon
    • PPS PTFE
    • Rulon L
    • Rulon J
    • Rulon AR

The general geometrical shapes include those for general purpose, rod or piston seals, face seal, and flanged rotary.

Advanced EMC Technologies’ Suggestions

The longevity of a spring energized seal can be significantly improved depending on several factors in the design process. You should ensure that the surface being sealed is designed for efficiency. This is influenced heavily by material choice, surface finish, and the hardness of the surface material.

The importance of design also applies to the surface finish as well. A surface finish that is too rough will cause the seal to wear more quickly. However, on the contrary, a surface that is too smooth will result in an improper transfer from the PTFE seal to the surface. That’s why Advanced EMC Technologies recommends using a surface finish between 2 and 16 RMS when it comes to spring energized seals. The surface finish will depend on the temperature and the type of media involved.

You should also account for the hardness of the surface because of its importance for adhesion. When the surface is too soft, the seal can be compromised. You’ll want to ensure that the surface has the proper hardness to lower the friction.

Material selection and surface treatment are also just as crucial to a seal’s performance. If the material you use isn’t hard enough, you’ll want to enforce the shaft with a surface finish. The combination of the proper material and surface treatment ensures the durability and strength of the shaft. Different types of surface treatments you should consider during the design process include:

PFTE Seal Performace Factors

There are a variety of factors that affect seal performance. These must be addressed during the design stage to ensure the maximum amount of reliability on these seals. This includes:

  • Hardware Preparation: Surface Finish and Hardness
  • Polymer Jacket
  • Spring Energizer
  • Operating Conditions
  • Frictional Considerations
  • Lubrication
  • Extrusion Gap / Radial Clearance
  • Spring Loaded vs. Deflection

Advanced EMC Technologies’ PTFE Seals

Advanced EMC Technologies strives to provide you with the highest-quality materials. Our team of technical engineers is always ready to assist you with any questions regarding the design, application, or use of our PTFE seals in your product. We are consistent, accurate, on time, and a budget.

Advanced EMC Technologies was built on real values and can provide effective, appropriate solutions to the customer’s needs and product requirements. We understand that our customers have schedules to keep and must compete in the global marketplace. Our in-depth knowledge of strategic partners and materials allows us to compete in every application. If we can’t produce a product at the lowest overall cost in the U.S., we have relations with qualified Asian and Mexican sources.

With over 100 years of industry experience and a leading provider of polymer sealing solutions, consider Advanced EMC Technologies for any of your spring energized Teflon seal needs!