Piston Seals · PWM

Operating Conditions
Pressure | Up to 50 MPa |
Speed | Up to 10 m/s |
Temperature | -45 °C to +200 °C. Depending on seal and O-Ring material |
Media | Mineral oil-based hydraulic fluids, flame retardant hydraulic fluids, environmentally friendly hydraulic fluids (bio-oils), phosphate ester, water and others, depending on temperature, seal and O-Ring material compatibility - see Materials for PWM. |
Clearance | The maximum permissible radial clearance Smax is shown in Installation Dimensions, as a function of the operating pressure and functional diameter. |
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 depends on media.
Recommended Materials
The following material combinations have proven effective for hydraulic applications:
PWM in PS8WM
All round material for light to heavy hydraulic applications linear, short stroke or helical movements in mineral oils, flame retardant hydraulic fluids, phosphate ester, bio-oils or fluids having low lubricating properties:
O-Ring | NBR 70 Shore A | N |
FKM 70 Shore A | V | |
Set Code | PS8WMN or PS8WMV |
For specific applications, all PTFE materials are available.
Other material combinations are listed in Materials for PWM.
Materials for PWM

Installation Dimensions - Standard Recommendations

Series No. | Bore Diameter DN H9 | Groove Diameter | Groove Width | |
Standard Application | Available Range | d1 h9 | L1 +0.2 / -0.0 | |
PWM | 8 - 14.9 | 8 - 140 | DN - 4.9 | 2.20 |
PWM | 15 - 39.9 | 12 - 140 | DN - 7.5 | 3.20 |
PWM | 40 - 79.9 | 15 - 320 | DN - 11.0 | 4.20 |
PWM | 80 - 132.9 | 40 - 400 | DN - 15.5 | 6.30 |
PWM | 133 - 329.9 | 80 - 700 | DN - 21.0 | 8.10 |
Series No. | Radius | Radial Clearance Smax | O-Ring Cross Section | ||
r1 max | 10 MPa | 20 MPa | 40 MPa | d2 | |
PWM | 0.4 | 0.40 | 0.30 | 0.20 | 1.78 |
PWM | 0.6 | 0.60 | 0.50 | 0.30 | 2.62 |
PWM | 1.0 | 0.70 | 0.50 | 0.30 | 3.53 |
PWM | 1.3 | 0.80 | 0.60 | 0.40 | 5.33 |
PWM | 1.8 | 0.80 | 0.60 | 0.40 | 7.00 |
Ordering Guide
PWM complete with O-Ring, standard application:
Series | PWM |
Bore Diameter | DN = 80.0 mm |
TMK Part No. | PWM0800081 |
PWM 0800 081 PS8WM N
1 2 3 4 5
1 | TMK Series No. |
2 | Bore Diameter x 10 |
3 | Groove Width x 10 |
4 | Material Code ( Seal Ring ) |
5 | Material Code ( O-Ring ) |