A metal energizing spring installed within the pan seal provides preload. This provides the seal with permanent elasticity, unaffected by fluctuations in operating temperature, pressure, or chemical processes.
Three common spring types: V-type spring (cantilever spring), H/O-type (helical spring), and C-type (canted coil spring).
Three common spring materials:
SS300 series stainless steel (general use): oil, grease, air, water, steam, solvents, food, pharmaceuticals, gases, etc.
Hassler C-276 (corrosive media): acids, corrosives, seawater, etc.
Elgiloy® (petrochemical): crude oil, sour natural gas, etc.
Spring Performance Factors:
Each of the three spring designs has unique performance characteristics. In addition to corrosion resistance, the most important characteristics are load capacity and deflection range. These factors directly affect the sealing ability, friction, and wear rate of the seal. Spring load directly affects sealing performance, friction, and wear rate. Increasing load increases seal lip compression, which in turn increases friction and wear. The spring deflection range determines the seal's ability to compensate for cavity tolerances and normal wear. All three spring types have specific deflection ranges. As the cross-sectional dimensions of the seal and spring increase, the effective deflection range also expands, impacting the selection of different cross-sectional specifications. When there is misalignment of the sealing surface, a spring with a wide deflection range should be preferred. See the performance characteristic curves below.
V-type cantilever spring
V-springs are standard springs, commonly made of 300 series stainless steel or Elgiloy®. A V-shaped structure is formed by stamping or chemically etching the strip material into a serpentine pattern. The spring acts like a series of "cantilever beams," expanding from an arc at the base of the spring. The spring's shape concentrates the load at the leading edge of the sealing lip, providing reliable wiping action. Different V-spring designs are available to accommodate light and medium loads.
Applications: Designed specifically for dynamic seals operating in rotating or reciprocating motion, they are also suitable for static applications requiring a wide range of deflection capabilities, such as those involving large cavity tolerances, significant thermal expansion and contraction, or seal lift caused by high pressure. Because the cantilever beam structure concentrates the spring load at the leading edge of the seal, V-springs offer optimal wiping when using a scraping lip in abrasive media.
• Reciprocating rod and piston seals
• Rotating shaft seals with linear speeds < 0.5 m/s
• Static seals for wide tolerances and misalignment
• Abrasive media environments
• Dynamic seals exceeding 200°.
When cross-sectional dimensions and diameters do not match, the springs can be overlapped at the ID or spread out at the OD. The individual springs with gaps provide flexible adaptability, and the V-shaped design allows for flexible application in both radial and axial sealing designs. Minimum diameters apply when used as rod seals, piston seals, and internal/external pressure face seals. Please contact us for details. If the minimum diameters are outside these limits, H- or C-type springs are available.
H-type coil spring
Coil springs are coiled from flat metal strip, typically made of 300 series stainless steel or Elgiloy®, into a helical structure. Compared to V- or C-type springs, they offer higher unit loads and shorter deflection ranges. Their tightly packed coils provide near-continuous load distribution, significantly reducing potential leak paths. Optimized for static sealing applications, their high unit load characteristics make them suitable for low-speed, low-frequency dynamic applications where friction and wear are less important than absolute sealing. The unique design of the coil spring and seal body precisely concentrates the load at the contact point, creating a strong seal. They exhibit high load-deflection characteristics.
Applications: Ideal for static and slow-moving applications where friction and wear are not critical. Their high unit load characteristics are particularly well-suited for vacuum, low-temperature, or low-pressure applications where the self-energizing seal is insufficient. However, their limited deflection range makes them unsuitable for wide tolerances, eccentricity, or misalignment.
• Static rod and piston seals
• Static internal/external pressure end face seals
• Low-speed dynamic applications with linear speeds <1 m/s
• Vacuum seals
• Critical applications requiring extremely high sealing reliability
C-type canted coil spring
Canted coil springs are formed from round wire using a canted coiling process, resulting in radial compression springs with a flat load-deflection curve and a relatively constant load over a wide deflection range. When the compressive load is applied to the center of the seal, the standard canted lip seal structure shifts the contact point slightly forward, forcing the spring back into the spring chamber. This lip design creates a concentrated unit load at the sealing interface while allowing lubricant to penetrate the dynamic lip, effectively extending wear life.
Depending on the spring design, three load ratings are available: light, medium, and heavy.
Commonly used canted coil springs in China have a light load and a small deflection range. This allows for precise friction control over the seal's operating life, preventing damage to the spring due to excessive seal deformation. They are suitable for applications where sealing performance is less important than friction control, providing extremely low starting force and operating friction.
Medium Duty: A general-purpose option that balances friction coefficient, sealing performance, and dynamic wear. Recommended as the initial choice for new applications.
Heavy Duty: Suitable for applications requiring optimal resilience during hardware separation. It exhibits a higher dynamic wear rate but ensures absolute sealing performance.
Applications:
• Friction-sensitive applications
• Reciprocating rod and piston seals
• Rotating shaft seals with linear speeds <5 m/s
• Wide tolerances and misalignment chamber configurations
• Dynamic high-temperature applications exceeding 200°C
• Compact seals with diameters under 13 mm and cross-sections of 2.4 mm.
