Heavy-Duty Bi-Directional Piston Seal with Live Back-Up Rings

Squeeze-type piston seal for use on vertical or no-drift piston. Positive actuated live back-up rings to eliminate seal extrusion in high-pressure applications or larger extrusion gaps. Requires split piston design for smaller diameters for easier fitment.

Operating Range
MaterialOperating Pressure up toMaximum Pressure up toTemperatureSurface Speed up toFluid, Media
Duralast 42035,000psi (350bar)10,000psi (700bar)-22°F to 260°F (-30°C to 125°C)1.6ft/s (0.5m/s)mineral oil-based fluids, fire-resistant water-based hydraulic fluids including HFA and HFB, sea water, biodegradable fluids, vegetable oils, bio-diesels, and most modern hydraulic fluids
Duralast 44038,000psi (520bar)14,500psi (1000bar)-22°F to 260°F (-30°C to 125°C)1.6ft/s (0.5m/s)same as Duralast 4203
Duralast 81663,800psi (260bar)5,000psi (350bar)-4°F to 392°F (-20°C to 200°C)3.2ft/s (1.0m/s)fire-resistant fluids, phosphate esters, mineral oils, greases, and most inorganic acids and chemicals, gasoline and gasoline/alcohol blends, hard vacuum
Duralast 51013,800psi (260bar)5,000psi (350bar)-22°F to 212°F (-30°C to 100°C)1.6ft/s (0.5m/s)mineral-oil based hydraulic fluids, silicone greases, petroleum-based oils, water and alcohols
Duralast 61463,800psi (260bar)5,000psi (350bar)-30°F to 302°F (-35°C to 150°C)2.0ft/s (0.7m/s)excellent heat and oil resistance, including exposure to such oil additives as detergents, anti-oxidants and anti-wear agents
Additional standard materials available: High-performance polyurethanes, NBR (Nitrile), FKM, Viton®, HNBR, EPDM, Aflas®, Hytrel®, Silicone, low- and high-temperature, FDA-compliant seal material grades, PTFE, filled PTFE®, engineered thermoplastics and proprietary specialized Duralast™, Duraloy™, and Permachem™ materials.
*Important Note: Maximum values above depend on extrusion gap, clearances, seal material, media, temperatures, pressures, surface speed, dynamic running surface finish and working environment. Seals cannot be operated at their upper ratings at the same time. Pressure ratings can be increased by reducing clearances. For pressure above specified operating pressure, please contact engineering@ahpseals.com
Size Table (Inch)The standard range sizes listed below are the preferred sizes for new design applications. Seals are available for any bore size in 0.001inch increments, including functional range. Additionally, we offer any other seal size as required.
Bore Diameter
Groove Diameter
Piston Diameter
Standard RangeFunctional RangeToleranceD=B=D,BTol.+0.008/-0min.max.max.
2.000 - 2.999"1.500 - 5.000"+0.002/-0.250A - 0.500A - 0.028+0/-.0030.5000.0450.0200.006
3.000 - 5.999"2.000 - 8.000"+0.003/-0.313A - 0.626A - 0.029+0/-.0040.6250.0600.0200.006
6.000 - 9.499"2.500 - 18.000"+0.003/-0.375A - 0.750A - 0.030+0/-.0040.7500.0750.0250.008
9.500 - 12.249"4.000 - 28.500"+0.004/-0.500A - 1.000A - 0.031+0/-.0051.0000.1000.0300.008
12.500 - 28.499"6.500 - 28.500"+0.006/-0.625A - 1.250A - 0.032+0/-.0061.1800.0700.0300.012
> 28.500consult with Ahpseals engineering
* Based on using wear rings. For pressure above 5,000psi, please contact engineering for clearances. Surface finish: bore (A) Ra 4-12µin – Static (D,L) Ra max. 32µin. See Technical Info for more specific information.

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