K8


Low-Friction Bi-Directional Hydraulic Piston Seal

O-ring-energized filled-PTFE cap seal design provides smooth movement, low friction and wear in low- to medium-duty piston sealing applications. The small axial seal height reduces piston height, weight and cost. Commonly used in hydraulic presses, machine tools, injection molding machines and mobile hydraulics. Retro fits seals of similar design.




Operating Range
MaterialOperating Pressure up toMaximum Pressure up toTemperatureSurface Speed up toFluid, Media Compatability
Permachem 66433,800psi (260bar)5,000psi (350bar)-40°F to 400°F (-40°C to 210°C)13ft/s (4m/s)mineral oil-based fluids, fire-resistant water-based hydraulic fluids including HFA and HFB, biodegradable fluids, vegetable oils, bio-diesels, and most modern hydraulic fluids
Permachem 61505,000psi (350bar)6,000psi (420bar)-40°F to 400°F (-40°C to 210°C)13ft/s (4m/s)same as Permachem 6643
Additional standard materials available: PTFE, filled PTFE®, engineered thermoplastics, high-performance polyurethanes, NBR (Nitrile), FKM, Viton®, HNBR, EPDM, Aflas®, Hytrel®, Silicone, low- and high-temperature, FDA-compliant seal material grades 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, surface speed above 5ft/s (1.3m/s), or for any advice, 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.
A
Bore Diameter
CS
Cross-Section
D
Groove Diameter
B*
Piston Diameter
ToleranceL
Groove Width
CR1R
Standard RangeFunctional RangeToleranceD=B=D,BTol.+0.008/-0min.max.max.
0.312 - 0.564"0.300 - 0.599"+0.001/-00.097A - 0.194A - 0.024+.000/-.0010.0870.0450.0150.006
0.565 - 1.499"0.550 - 1.599"+0.002/-00.148A - 0.296A - 0.024+.000/-.0020.1260.0500.0250.008
1.500 - 3.124"0.550 - 12.000"+0.003/-00.217A - 0.434A - 0.027+.000/-.0030.1650.0700.0250.008
3.125 - 5.249"1.500 - 18.500"+0.003/-00.305A - 0.610A - 0.029+.000/-.0030.2480.1000.0350.008
5.250 - 12.499"3.000 - 26.500"+0.004/-00.414A - 0.828A - 0.030+.000/-.0040.3200.1300.0350.008
12.500 - 26.599"5.000 - 26.500"+0.005/-00.483A - 0.966A - 0.034+.000/-.0050.3200.1300.0350.008
26.600 - 40.124"10.000 - 50.000"+0.007/-00.552A - 1.102A - 0.045+.000/-.0070.3750.1500.0400.012
40.125 - 72.500"20.000 - 72.500"+0.009/-00.748A - 1.496A - 0.050+.000/-.0090.5430.1700.0500.012
> 72.500" consult with Ahpseals engineering
* Based on using wear rings. For pressure above 3,800psi or diameter 26,500", please contact engineering for clearances. Surface finish: rod (A) Ra 4-12µin – Static (D,L) Ra max. 32µin. See Technical Info for more specific information.

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