A spring-energized seal is a lip seal made of PTFE/Teflon or ultra-high molecular weight polyethylene/PEEK and equipped with an energizing spring. The spring continuously applies pressure to the sealing lip. By selecting the right corrosion-resistant spring type, it can effectively seal low-pressure or fluctuating pressure conditions.
Compared to other polymer elastomers (polyurethane, rubber), spring seals offer longer service life. As the seal body wears, the energizing spring compensates by providing spring force, maintaining a constant and uniform force on the sealing lip, thereby maintaining sealing pressure. This reduces maintenance intervals and increases equipment uptime. The use of PTFE, a chemically compatible and wear-resistant material, reduces media contamination and minimizes the possibility of seal material dislodgement.
Hydraulics, vacuum pumps, and valves are the most common applications for spring-energized seals. They excel in addressing critical issues such as leakage, wear, and corrosion in these fluid/vacuum equipment. They are typically used as rotary/reciprocating seals and static/face seals.
Material Properties:
Temperature Resistance Range:
-200~260°C. The bond energy is extremely high, requiring PTFE molecules to absorb significant heat before they begin to decompose. The symmetrical molecular chain structure maintains structural stability even at high temperatures, making it resistant to chain breakage or rearrangement.
Chemical Resistance:
Due to the extremely strong and stable chemical bonds within PTFE's molecular structure, as well as the insulating and protective effect of the fluorine atoms, virtually no substance can remove the fluorine atoms or react strongly with them. The surface is extremely smooth, making it difficult for other molecules to adsorb or interact with it. The larger atomic radius of the fluorine atoms physically protects the carbon backbone within, making it difficult for various chemical molecules to attack. It is resistant to oxidation and is virtually insoluble in all solvents at room temperature. It is acid and alkali resistant.
Physical Properties:
Pure PTFE lacks strong bonds between molecules (weak intermolecular forces), making it prone to slippage. Under sustained stress, PTFE will slowly deform—creep/cold flow.
Improved Physical Properties:
Given PTFE's inherently weak physical properties, in actual sealing applications, fillers are often added to composite PTFE materials. These include glass fiber to improve compressive strength and extrusion resistance, copper powder to improve thermal conductivity and wear resistance, carbon fiber to enhance mechanical strength and dry friction performance, graphite to improve lubricity, and other fillers such as molybdenum disulfide and cadmium oxide. Different filler ratios provide varying physical properties. In addition to being commonly used in extruded (elastomer extruded) sliding seals like Gladstone seals, spring-energized seals utilize corrosion-resistant metal springs (SS316, Hastelloy, Inconel, and other corrosion-resistant metals) to provide consistent and stable sealing, offsetting PTFE's inherent cold flow resistance and enhancing PTFE's inherent unparalleled chemical and temperature resistance.
Raw Material Price Differences and Production Requirements:
Different quality grades of filled PTFE are difficult to distinguish visually, and the price difference between low- and high-grade raw materials can be as much as 3-4 times.
The production of modified PTFE is a delicate process that prioritizes both formulation and process. Subtle differences in the production process, such as preform pressing pressure, process control during core sintering, and filler particle size and mixing uniformity, can affect the temperature resistance and physical properties of modified PTFE in sealing systems, leading to instability and variability in sealing performance.
Klock Seals has consistently used high-quality raw materials from leading domestic suppliers and first-tier importers for decades, ensuring the stability and consistency of PTFE sealing rings. Leveraging its technical resources and production capabilities, we develop customized materials to meet diverse customer needs, serving a wide range of industrial sectors.
