description

O-Ring activated symmetric PTFE rod seal, low friction. for extreme low or high speed, suitable for positioning functions.

 

  • asymmetric double-acting composite rod seals, with a gliding part made of low friction material and an elastic preload element.
  • interference fit on the outside diameter.
  • various materials are available for different purposes.
  • snaps into simple grooves (see notes on installation).
  • the generously dimensioned chamfer reduces the risk of gap extrusion.
  • good sealing effect across a wide temperature range.
  • for pressures up to 400 bar (in special cases up to 800 bar) as a seal betweenpressurised spaces.
  • good sealing in all pressure ranges.
  • good static and dynamic sealing.
  • suitable for short and long travel with extremely slow or quick movements.
  • no stick-slip.
  • small break-awayload after prolonged periods of standstill.
  • exact positioning due to little friction.
  • high mechanical efficiency.
  • insensitive to thermal damage caused by air in the oil.
  • radial grooves assure a fast pressure activation of the seal (design and arrange-ment see “fabrication  tolerances for machined seals” es 222.209-d).
  • this seal can run over holes which are smaller than nominal seal height if theholes have suitable chamfered edges.

 

application

 

not bolded symbols; please consult our technical for application limitations

 

category of profile

machined or molded/standard/trade product.

 

double acting

the RS09-A seal is designed  for use as a piston seal.

 

area of application: hydraulics

  • reciprocating rods on hydraulic cylinders,small swivelling motion permissible.
  • main field application is pressure intensifiers and control elements.
  • dimensions according to ISO 7425 part 2 are common, as well as standard types that differ slightly in the depth of the mounting

space. for specific dimensions see “range of profile sizes”.

 

note

  • there should be enough space for trailing oil.
  • the recovery capacity depends on the sealing system.
  • because of the fluid transport between the pressurized spaces this seal is only suitable to seal same media.

 

function

RS09 profiles are composite rod seals designed to seal between two pressurised spaces; mainly for reciprocating movements. the design

is based on application in standard hydraulic systems with conventional hydraulic oils. the operating parameters are as defined in the seal-

ing data sheet and material data. requirements deviating from these parameters can be met to a certain degree by changing the geom-

etry in the software program.

for detailed information regarding chemical resistance please refer to our “list of resistance”. for decreased leakage rates elastomer materials (polyure-

thane or rubber) in other sealing systems are to be preferred.

note on special materials:

as temperature limit and chemical resistance are determined by the preload element, the temperature range can be increased and the resis-

tance to chemical influences improved, if a special material is used for the preload element.

 

gap dimension

 operating pressure  cs = (ØD - Ød)/2 mm
2.45 3.65 5.35 7.55 10.25 12 13.65
 safe extrusion gap (mm)
100 bar (10 MPa) 0.27 0.33 0.38 0.43 0..50 0.55 0.60
200 bar (20 MPa) 0.19 0.25 0.28 0.33 0.37 0.43 0.45
300 bar (30 MPa) 0.17 0.20 0.22 0.25 0.30 0.34 0.38
400 bar (40 MPa) 0.16 0.18 0.19 0.21 0.25 0.28 0.30

 

important note:

the above data are maximum values and cannot be used at the same time. e.g. the maximum operating speed depends on material type, pressure, temperature and gap value. temperature range also dependent on medium”

the table  refers to a operating  temperature of 80°C. temperatures  below may increase the safe extrusion gap slightly, at temperatures above

80 °C, the gap dimensions has to be reduced or a stronger profile selected.

for extrusion gap sizes resulting from tolerance  pair H8/f8 pressure ranges above 400 bar can be reached  in special cases, influences due to

thermal expansion have to be considered. we recommend to contact our technical department.

 

surface quality

surface roughness

Rtmax (μm)

Ra (μm)

sliding surface ≤2,5 ≤0,1-0,5
bottom of groove ≤6,3 ≤1,6
groove face ≤15 ≤3

 

tolerance recommendation

seal housing tolerances
Ød f8
ØD H10

 

mode of installation

for inside diameters of 25 mm or more, and dependant  on radial cross section (cs), seals may be snapped into a closed housing.

Ød type of installation
≤ 6•cs open mounting space required
> 6•cs .....≤ 10•cs snap mounting with tool
> 10•cs snap mounting by hand

 

recommended guide tolerance D1:

in most cases the guiding elements are integrated in the piston seal system on both sides. if not use below recommendations  for D1 (=inside diameter of the guiding elements):

d f8 [mm] p ≤ 100 [bar] 100 < p ≤ 200 [bar] p > 200 [bar]
≤ 100 H10 H8 H8
> 100 ≤ 200 H10 H8 H7
>200 >20 H8 H7

 

 

insertion chamfer:

in order to avoid damage  to the rod seal during installation, the piston rod is to be chamfered  and rounded  as shown in the “recommended mounting space” drawing. the size of chamfer depends on the seal type and profile width.

cs (mm) c (mm)
α = 15⁰  ... 20⁰ α = 20⁰  ... 30⁰
2.45 2.5 1.5
3.5 3.5 2
5.35 4.5 3
7.55 5 3.5
10.25 6 5
12 8 6
13.65 10 7

 

 

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...

  the ratio between  nominal width and seal height should be in accordance  to ISO 7425 part 1. we recommend the following values:

 

Ød [mm] ØD [mm] L [mm] cs = (ØD - Ød)/2 [mm]
5 ~ 7,9 Ød + 4,9 2.2 2,45
8 ~ 18,9 Ød + 4,9 3.2 3,65
19 ~ 37,9 Ød + 10,7 4.2 5,35
38 ~ 199,9 Ød + 15,1 6.3 7,55
200 ~ 255,9 Ød + 20,5 8.1 10,25
256 ~ 649,9 Ød + 24 8.1 12
650 ~ 1.000 Ød + 27,3 9.5 13.65
> 1.000 Ød + 27,3 9.5 13.65

in case of large deviations of L use RS 09-A.

 

fitted:

 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.