Low-Friction Bi-Directional Hydraulic Piston Seal-K8E

K8E


Low-Friction Bi-Directional Hydraulic Piston Seal

Cap seal providing low friction and long service life over a wide range of light- to medium-duty bi-directional service applications. The K8E retrofits into standard O-ring grooves designed for no back-up, single, or two back-up rings without modification. The specially designed filled-PTFE cap resists extrusion and twisting of the O-ring under higher pressure.




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 Teflon®, 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)Standard sizes listed below are preferred sizes for new design applications; however, we offer any other seal size as required. Seals are available for any shaft diameter size in 0.001 inch increments without tooling charges, including Functional Range.
A
Bore Diameter
CS
Cross-section
D
Groove
Diameter
B
Piston
Diameter
Tolerance
L
designed for
no back-up
ring groove
L
designed
for 1 back-up
ring groove
L
designed
for 2 back-up
rings groove
C
R1
Radius
R
Radius
Standard Range
Functional Range
Tolerance
*D=
B=
D, B
Tolerances +0.005/-0
min.
max.
max.
0.250-0.499"
0.250 - 3.000"
+0.001/-00.065
A - 0.130
A - 0.002
-0.001/+0
0.090
0.140
0.205
0.040
0.015
0.005
0.500-0.999"
0.310 - 4.000"
+0.002/-0
0.098
A - 0.196
A - 0.002
-0.002/+0
0.140
0.170
0.240
0.060
0.020
0.005
1.000 - 1.499"
0.430 - 6.000"
+0.002/-0
0.139
A - 0.278
A - 0.003
-0.002/+0
0.190
0.210
0.275
0.080
0.040
0.005
1.500 - 4.999"
0.810 - 10.000"
+0.003/-0
0.203
A - 0.406
A - 0.004
-0.003/+0
0.280
0.310
0.410
0.090
0.050
0.005
5.000 - 20.999"
4.500 - 26.000"
+0.005/-0
0.287
A - 0.574
A - 0.005
-0.004/+0
0.380
0.410
0.540
0.130
0.070
0.005
≥21.000"
consult AHPSeals engineering
*Standard cross-sections(CS) listed and non-standard sizes can be provided for any shaft size up to 63 inches. Surface finish: Shaft (A) plunge ground, zero lead, Ra 8-16µin using elastomer seals, Ra 6-12µin using PTFE seals. Housing (D,L) Ra 32-63µin,shaft material hardness 55-65RC. See Technical Info for more specific information.

Seal Size Selector – Request a Quote

  • Enter shaft, rod or bore diameter
  • If recommended size is not feasible, please enter your preferred dimensions
  • If recommended size is not feasible, please enter your preferred dimensions
Back to Products page
Seal Housing Drawing