T-Seal High-Pressure Bi-Directional Piston Seal

High-pressure compact piston seal design. The design utilizes two positively actuated live anti-extrusion back-up rings to support very high pressure from both sides. Available in Viton®, Nitrile, H-Nbr, Aflas® and other materials to retrofit standard O-ring grooves designed for no back-up, single, or two back-up rings. Retro fits seals of similar design.

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
Groove Standard*
Groove Medium*
Groove Narrow*
Standard RangeFunctional RangeToleranceD=B=D,BTol.+0.005/-0Tol.+0.005/-0Tol.+0.005/-0min.max.max.
0.375 - .499"0.500 - 2.000"+0.002/-00.088A - 0.176A - 0.002+0/-.0010.2400.1700.1400.0350.0200.006
0.500 - 1.749"0.500 - 6.000"+0.003/-00.121A - 0.242A - 0.003+0/-.0020.2750.2100.1900.0450.0200.006
1.750 - 5.124"2.500 - 26.000"+0.003/-00.185A - 0.370A - 0.003+0/-.0030.4100.3100.2800.0600.0200.006
5.125 - 26.500"4.000 - 26.500"+0.004/-00.237A - 0.474A - 0.004+0/-.0040.5400.4100.3800.0800.0200.006
26.500" ≥consult with Ahpseals engineering
*Standard groove to retrofit O-ring grooves with 2 back-up rings. Medium groove to retrofit O-ring grooves with one back-up ring. Narrow groove to retrofit O-ring grooves with no back-up ring.
**Based on using no wear rings. Surface finish: bore (A) Ra 4-12µin – Static (D,L) Ra max. 32µin. See Technical Info for more specific information.

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