description
the PS 08-D is a rubber energised plastic faced seal. the seal is designed to expand and improve the service parameters of O-Rings and is installed in existing O-Ring grooves. K08-SB combines the flexibility and response of O-Rings with the wear and friction characteristics of the PTFE series materials in dynamic applications. the double acting performance of the seal follows from the symmetrical cross section which allow the seal to respond to pressure in both directions. initial contact pressure is provided by radial compression of the O-Ring. when the system pressure is increased the O-Ring transforms this into additional contact pressure, the contact pressure of the seal is thereby automatically adjusted so sealing is ensured under all service conditions. the drawing below shows the cross section of K08-SB, without and with pressure.
application
not bolded symbols; please consult our technical for application limitations
category of profile
machined or molded/standard/trade product.
double acting
the PS 08-D seal is designed for use as a piston seal.
area of application: hydraulics
the PS 08-D is the recommended sealing element for double acting pistons of hydraulic or pneumatic cylinders in sectors such as:
- machine tools, handling devices, manipulators, valves, chemical process equipment.
- it is particular recommended for light duty and small diameter applications.
notches
PS 08-D is as standard supplied without radial notches, as the thin radial section of the seal gives good response to pressure variations. for diameters from 8 mm notches on both sides are optional. these ensure direct pressurizing of the seal under all operating conditions.
advantages
- compact groove dimensions and simple installation
- low friction without stick-slip
- resistance against wear and extrusion
- piston seals available for all diameters from 5 to 999.9 mm
- standard cross sections cover AS 568A and important metric O-Rings, other cross sections available on request
- fits also groove dimensions per MIL-G-5514F
operating parameters & material for standard application:
for hydraulic components with reciprocating movement in mineral oils containing zinc or medium with good lubricating performance and hard mating surface.
standard material for hydraulics, high compressive strength, good sliding and wear properties, good extrusion resistance, BAM tested. mating surface material: steel tubes, steel hardened cast iron
colour: greyish to dark brown
operating parameters & material for special application:
short stroke movements, poor lubricating fluids and soft mating surfaces. for all lubricating and non-lubricating hydraulic fluids, soft matings urfaces
mating surface material: steel, steel hardened cast iron, stainless steel, aluminium, bronze colour: black
important note:
the above data are maximum values and can’t be used at the same time. e.g. the maximum operating speed depend on material type, pressure, tem- perature and gap value. temperature range also dependent on medium.
the diagram applies to an operating temperature of 70 °C.
1 pressure ratings are dependent on the size of the extrusion gap.
2 attention: not suitable for mineral oils!
gap dimension
important note:
the above data are maximum values and can’t be used at the same time. e.g. the maximum operating speed depend on material type, pressure, tem- perature and gap value. temperature range also dependent on medium.
surface quality
| surface roughness | material |
Rtmax (μm) |
Rz DIN [µm] |
Ra (μm) |
| mating surface | PTFE + …… | 0.63 – 2.50 | 0.40 – 1.60 | 0.05 – 0.20 |
| PU & Rubber | 1.00 – 4.00 | 0.63 – 2.50 | 0.10 – 0.40 | |
| groove surface | < 16 | < 10.0 | < 1.6 | |
tolerance recommendation
| seal housing | tolerances |
| Ød | h9 |
| ØD | H9 |
lead-in chamfers
in order to avoid damage to the seal during installation, lead-in chamfers and rounded edges must be provided on the bore or piston rod (see drawing below).
the minimum length of the lead-in chamfer depends on the profile size of the seal and can be seen from the following tables.
seal & housing recommendations
please note that we are able to produce those profiles to your specific need or any non standard housing. for detail measurements, please see Jet seal pars catalog…
don’t hesitate to contact our technical department for further information or for special requirements (temperature, speed etc.), so that suitable materi- als and/or designs can be recommended.
lead-in chamfers
in order to avoid damage to the seal during installation, lead-in chamfers and rounded edges must be provided on the bore or piston rod (see drawing below).
the minimum length of the lead-in chamfer depends on the profile size of the seal and can be seen from the following tables