Hydraulic & Fluid Seals

The rod seal is the most critical seal on any type of fluid power equipment. A leaking rod seal not only reduces equipment performance, but also causes environmental issues. Our rod seals are available for both:
- single-acting: capable of sealing dynamic pressure from one side (unidirectional)
- double-acting: capable of sealing dynamic pressure from both sides (bidirectional)

Particular attention should be paid to selecting the best rod seal for your application. It is important to properly pair the rod seal and the wiper for the best sealing performance. If a less aggressive rod seal is paired with an aggressive wiper, the wiper can scrape off the microscopically thin film of oil that remains on the rod in microscopic surface imperfections during the return stroke, resulting in system leakage. The thickness of the oil film depends upon the surface finish, rod seal and surface speed of the rod. For more information go to High-Performance Sealing System.

Non-symmetrical Rod Seal Design
Our rod seals are non-symmetrical lip or squeeze type rod seal designs in which the diameter of the seal is oversized (Fig.2), and are available for both bidirectional and unidirectional applications. This seal design creates a hoop pressure and ensures a high static sealing force over the entire surface of the outside diameter of the seal, providing significantly higher stability of the seal during operating cycles and eliminating rocking and pumping effects, thereby improving sealing performance. Instability of a seal can create leakage and seal damage.

• Non-symmetrical rod seals are seals where the shape of the outside diameter lip differs from the inside diameter (see Fig. 1).
• Non-symmetrical rod seals provided by AHPSeals are not centered in the gland and provide sealing contact (hoop pressure) with the gland across the entire surface of the outside seal diameter (Fig. 2).
• Non-symmetrical rod seals provide better sealing performance than symmetrical seals do.

Fig. 1 Cutaway view of a non-symmetrical rod seal S17	Fig. 2 Uninstalled view of a non-symmetrical rod seal S17	Fig. 2b Installed view of a non-symmetrical rod seal S17

Lip vs. Squeeze Type Seals
The basic design of a seal significantly affects the overall function of the seal, especially at low pressures. One of the most challenging applications is linear dynamic sealing at low pressure while providing low breakaway and running friction. AHPSeals provides a series of low-friction seals for these challenging applications.

• Lip seals: are without any energizing rubber elements; therefore, they provide a more flexible dynamic seal lip and are generally characterized by low friction, low wear and poor low-pressure sealing capabilities.
• Squeeze seals: typically incorporate an energizing rubber element and are generally characterized by high friction, high wear and good low-pressure sealing. To avoid a pressure trap between two seals and potential seal failure, do not use energizer-loaded seals for back-to-back bidirectional piston sealing applications.

Seal Lip Geometry:

• Beveled seal lip or chamfered seal lip is the most aggressive seal lip design. Most of our rod seals feature this lip design as it provides the best fluid film breaking ability, which provides the best sealing performance. Sealing lips for all AHPSeals’ rod seals are precision machined for a sharp sealing edge that cannot be achieved by a net-molding process (Fig. 3).
• Knife-edge and straight seal lip designs offer good scraping properties but reduced sealing performance and are used for sealing applications with high fluid contamination (Fig. 4 and 5).
• Rounded seal lip is the least aggressive sealing lip and is typically used in pneumatic applications to maintain a microscopically thin oil or grease film on the bore to keep the piston bearing and seal lubricated (Fig. 6).

Rod Seal SIZES & AVAILABILITY

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Rod Seal SIZES & AVAILABILITY

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Rod Seal SIZES & AVAILABILITY

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Rod Seal SIZES & AVAILABILITY

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• American High Performance Seals designs and manufactures some of the most durable (bold) rod seals complying with ISO 9000 quality standards.
• We utilize advanced materials engineered specifically to offer maximum durability and sealing performance.
• We provide a comprehensive range of seals and material options to meet industry’s challenging fluids, temperatures, surface speeds and pressures.

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