PTFE spring energized seals offer extreme temperature, high pressure, chemically inert static and dynamic sealing for the most demanding applications. Our thin flexible PTFE sealing jacket, resilient by design, utilizes a spring designed to apply outward pressure to the sealing element at low pressures.
A highly efficient seal is created as the system pressure increases enough to take over from the spring and engage the shaft or bore. The spring or energized seal assembly provides permanent resilience to the seal jacket and compensates for jacket wear, hardware misalignment and eccentricity. The jacket material is critical in design to assure proper seal performance.
We offer PTFE compounds specific to the application, such as:
- High PV seals
- Cryogenic seals
- High temperature seals
- PTFE seal alloys with fillers including PTFE Graphite, PTFE Polymide, PTFE Carbon, PPS PTFE, Rulon L, Rulon J and Rulon AR equivalents, and others
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|Fluorolon||Description||Application||Temp. Range F.||Extrusion Resistance||Friction Rating|
|1000||Virgin PTFE||Light duty service, lowest friction, FDA approved, Excellent for cryogenic and low molecular weight gas service.||-440 to 450||Lowest||Lowest|
|1034||Carbon/Graphite PTFE||Excellent resistance to heat and wear. Recommended for dry or semi-dry applications. Good in liquids and steam.||-320 to 500||Moderate||Low|
|1017||Moly/Filled PTFE||Excellent in dry gas with better wear resistance than Fluorolon 1000.||-320 to 525||Very High||Low|
|1050||Glass/Moly PTFE||Excellent wear and heat resistance. High pressure applications, good in hydraulic,steam and water. Abrasive in rotary service against soft metals.||-250 to 550||Very High||Moderate|
|1060||Polyimide/Filled PTFE||Excellent in dry service with low wear rate in vacuum and inert gases. Very low abrasion to dynamic mating surfaces.||-450 to 500||Very High||Low|
|5000||UH/Polymer PE||Excellent wear and extrusion resistance in aqueous media. FDA Approved. Has higher friction than PTFE compounds.||-320 to 175||Very High||High|
|1028||60% Bronze / filled PTFE||Excellent pressure capability even at high temperatures. Excellent at very high rotary speeds with low pressure||-320 to 450||Lowest||Moderate|
|2800||PCTFE / KEL F||Best grade for cryogenic applications. Static and slow dynamic.||-350 to 300||Lowest||High|
Typical Seal Geometries: Cantilever and Helical Designs
|General Purpose||Rod/Piston Seal||Face Seal||Flanged Rotary|
Spring Energizers For Spring Loaded Seals
|S301||301 Stainless Steel||General purpose for service to 550 F. Not recommended for highly corrosive media.|
|HST||Hastelloy C-276||Recommended for highly corrosive media.|
|E||Elgiloy||For service in salt water, severe media or milder corrosives over 500 F.|
Design Recommendations for PTFE Seal Longevity
The longevity of a PTFE seal can be greatly improved by accounting for several factors during the design process. When working with a PTFE seal, you must ensure that the surface over which the seal slides or rotates is designed for efficiency. The three factors that most heavily influence the longevity of a PTFE seal include the material choice, the surface finish, and the hardness of the mating surface.
Choosing the Optimal Surface Finish
In order for the PTFE seal to perform properly and efficiently, the surface finish must be designed appropriately. A surface finish that is too rough will cause the PETF seal to wear out more quickly, resulting in failure. However, a surface finish that is too smooth will not allow for the proper transfer of PTFE from the seal to the mating surface.
We recommend using a surface finish between 2 and 16 RMS when you are using PTFE seals. The surface finish you use will depend highly on both the temperature and the type of media involved.
When you are designing with PTFE seals in mind, it is important to ensure that the surface finish is rough enough to allow a thin film of PTFE to transfer to the mating surface. This will ensure that the seal does not leak or wear prematurely.
Accounting for The Hardness of Mating Surface
The primary concern regarding the hardness of the mating surface is adhesion. When the mating surface is too soft, the seal application can be compromised by adhesion. Ensure that the mating surface has sufficient hardness to lower friction. In doing so, you will reduce wear on both the PTFE seal and the mating surfacing, ensuring a long useful life of the seal.
Selecting the Material & Surface Treatment
If the material that you are using in the design process is not hard enough, you may need to fortify the shaft with a surface finish. This will ensure that the material resists adhesion, ensuring the longevity of the PTFE seal. Some of the types of surface treatments that you may consider during the design process include the following:
- Electroless Nickel Plating
- Hard Chrome Plating
- Gas Nitriding
The combination of an appropriate material along with a surface treatment ensures the strength and durability of the shaft. By considering these aspects of the product design, you ensure that your PTFE seals remain in good condition as long as possible.
Accounting for proper design when using PTFE seals will eliminate leaks, premature wear, or product failure. By considering important aspects such as surface finish, mating surface hardness, and the addition of surface treatment, you can ensure design success.
At Advanced EMC Technologies, we strive to provide you with the highest-quality materials. We have a team of technical engineers always ready to assist you with any questions regarding the application, design, or use of our PTFE seals in your product. Do you have questions regarding an effective design process for PTFE seals? Contact our team of experts today!