Piston seal, double-acting Type KD 04
The double-acting piston seal type KD 04 is a two-piece seal, consisting of a profile ring and an O-ring as a preload element. It is optimally suited for applications in the low pressure range and is used primarily in truck-mounted cranes and standard cylinders.
A low coefficient of friction and small installation height are the decisive advantages of this seal. It also possesses a high wear resistance, good service life and also a very good chemical and thermal resistance.
While the PTFE profile ring seals dynamically against the cylinder surface, the elastic O-ring ensures uniform contact pressure of the PTFE profile ring onto the cylinder surface, and at the same time, a static sealing between profile ring and groove base.
Even with low pressures, the piston seal shows good sealing effect due to the inherent preload of the PTFE profile ring and the contact force of the preloaded O-ring. At higher system pressures, the medium pressurizes the O-ring causing it to press the PTFE seal with enhanced force against the cylinder surface.
With the different material combinations, the piston seal can be used reliably across the whole pressure, speed and temperature range.
Application media
- Mineral oil-based hydraulic liquids
- Water
- Air
- Environment-friendly bio-oils
- Flame-resistant hydraulic liquids
- Other media, depending on the O-ring material
Application range
Pressure: up to 16 Mpa (160 bar)
Speed: approx. up to 2 m/s
Temperature: – 30 °C to + +100°C (depending on the O-ring material)
Surface finish
| Roughness depth | Ra | Rt |
| Running surface | ≤ 0,3 µm | ≤ 2,5 µm |
| Groove base | ≤ 1,6 µm | ≤ 6,3 µm |
| Groove flank | ≤ 3,0 µm | ≤ 15,0 µm |
Installation dimensions
| Cylinder ø D | |||
|---|---|---|---|
| over | to | Groove base ø D | Groove width L +0,2 |
| 9 | 22 | ø d – 6,1 | 3,2 |
| 22 | 55 | ø d – 7,2 | 4,0 |
| 55 | 150 | ø d – 12,2 | 7,5 |
PTFE profile ring material
PTFE + bronze
The standard for hydraulic applications, good gliding behavior, particularly pressure and abrasion resistant, cannot be used in aqueous solutions or acids
For other possible materials see our overview of PTFE materials in the technical information section.
O-ring material
Nitrile rubber NBR: Temperature range − 30 °C to + 120 °C
Materials overview for dynamic seals (PDF)
The following overview is a selection of typical PTFE materials used for seals, guide elements and wipers. Other PTFE materials are available for special applications.
Product data sheet (PDF)
Our data sheet for double-acting piston seals, Type KD 04 can be found here.
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