What Is a FlexiSeal®?
A FlexiSeal® is a spring-energized polymer seal consisting of:
- A precision lathe-cut jacket made from a PTFE-based Polon® or another high-performance polymer material
A metallic or polymer spring energizer
- One or more sealing lips designed to contact the mating surface
- An open jacket profile oriented toward the highest pressure side
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Unlike elastomer seals, FlexiSeals® do not rely on inherent elastic material behavior. The metallic spring provides a consistent energizing force, helping support sealing at low pressure and compensating for changes in the polymer jacket caused by wear, cold flow or thermal contraction.
How Does a FlexiSeal® Work?
When the FlexiSeal® is installed in the groove, the spring energizer pushes the sealing lips against the mating surfaces. The open end of the jacket is installed facing the highest pressure side.
As system pressure increases, the pressure acts inside the jacket and supplements the spring force. This hydrostatic loading improves contact between the sealing lips and the mating surfaces, creating an even tighter seal.
Functional Principle
- Spring energizing provides initial sealing force.
- Sealing lips contact the mating surfaces.
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System pressure enters the open jacket side.
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Hydrostatic force increases lip loading.
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The seal compensates for wear, cold flow and thermal contraction.
This design helps avoid compression-set limitations often associated with elastomer seals.
Key Advantages
- Reliable low-pressure sealing through spring energizing
- Pressure-assisted sealing due to open jacket orientation
- Resistance to compression-set issues typical of elastomers
- Wide range of PTFE-based and high-performance polymers
- Chemical compatibility options for demanding media
- High-temperature and cryogenic potential, depending on material and design
- Low-friction sealing behavior compared tomany elastomeric alternatives
- Wear-resistant "filled" compounds available for dynamic applications
- Customizable profiles for specific grooves and applications
- Precision lathe-cut manufacturing for application-specific dimensions
For more information, click here to view the brochure :
PTFE-Seals-Design-Guide.pdf
Frequently asked questions
1.What is a FlexiSeal?
A FlexiSeal® is a spring-energized polymer seal consisting of a PTFE-based jacket and a metallic spring energizer. The spring loads the sealing lips, while system pressure can supplement the sealing force. Unlike the inherent elastic behaviour of an elastomeric seal, a FlexiSeal® uses a metallic or polymer spring energizer.
2.How does a FlexiSeal® differ from an elastomer seal?
The spring energizer helps maintain sealing force and compensates for jacket wear, cold flow and thermal contraction. While elastomeric seals rely on inherent elasticity, a FlexiSeal® utilizes a metallic spring energizer to control elastic properties.
3.Which direction should a FlexiSeal® face?
The open end of the jacket should face the highest pressure side, so hydrostatic pressure can support the spring force and improve sealing.
4.Can FlexiSeals® be used in rotary applications?
Yes. FlexiSeals® can be used in selected rotary applications, but pressure, speed, lubrication, heat generation, surface finish and PV value must be evaluated.
5.Are FlexiSeals® available for standard O-ring grooves?
Yes. FlexiSeals® can be designed for selected international O-ring cavities or tailored to customer-specific groove geometries.
6.What materials are available?
FlexiSeal® jackets are available in PTFE-based and other high-performance polymer materials. Spring options include stainless steel, cobalt-chromium-nickel alloy, Inconel® and Hastelloy®.