Technische Informationen KDAQ doppeltwirkendTechnical information KDAQ double actiongTechnische Informationen KDAQ doppeltwirkendTechnische Informationen KDAQ doppeltwirkend
S.F. Components GmbH
主页 > 产品 > 聚四氟乙烯密封 > Piston seals > Technical information KDAQ double actiong

Piston Seals made of PTFE KDAQ

A double piston sealing of type KDAQ is proven and tested for sealing pistons for double-acting hydraulic cylinders, for media separation liquid/liquid or liquid/gas in particular. The compact design with two or more NBR-O-rings as pretension element on the static side well as a X-ring for media separation on the dynamic side, guarantee for a perfect sealing system. The various material combination for the sealing element as well as the selection of the material for the pretension and sealing element on the static and the dynamic side alike, provide for a large number of variation options and thus for a nearly unlimited usage for a wide variety of applications.

The piston sealing has a rectangular profile, the edges on the dynamic side a slightly trimmed. The sealing has radial grooves on both front sides in order to guarantee for a direct pressure on the sealing in case of a quick load change as well as to prevent any back pressure.

The KDAQ* design with two O-rings as a pretension element allows for higher deployment limits. Hence, this sealing can be recommended for heavy duty deployment as well as for larger diameters.


  • Excellent friction behaviour
  • No stick-slip effect, even with lower speeds
  • High sealing effect with media separation
  • Very good thermal and chemical durability
  • Higher gliding characteristics (KDAQ*)
  • Simple groove designg


Application ranges

Velocity:back and forth up to 2 m/s / 3 m/s*
Temperature:- 30° C to + 200° C
depends on material combination and O-Ring material
Pressure:up to 40 MPa (400 bar)
up to 60 MPa (600 bar)*
Groove root:Ra 1,6 µm / Rt 16 µm
Groove flanks:Ra 1,6 µm / Rt 16 µm
Contact area:Ra 0,3 µm / Rt 3 µm


Type KDAQ piston sealings can easily be installed in divided and undivided grooves.

In order to make installation easier, the sealing may be heated in oil at approx. 80 Co before installation.  After installing the pretension and sealing element, the PTFE piston sealing needs to be calibrated. Here, the cylinder pipe’s feed with an angle of approx. 15 Co and a length of between 2 mm and 8 mm, depending on the design of the sealing height, may be used. However, a calibration quill may be used as well. Generally, any sharp edges should be deflashed before attaching radiuses or bevels. Thread tips should be covered. Chippings, dirt and other foreign particles should be removed before installation.

After installation and calibration of the sealing, a X-ring is to be installed in the respective groove on the dynamic side.

In order to guarantee the sealing’s functionality and to not influence its life-cycle in a negative way, the surface quality of the area running in the opposite direction is decisive.

Generally, please make sure there are not marks, scratches or cavities as well as concentric or spiral toolmarks.

Key values such as Ra, Rz, Rt and Rmax, usually used to describe surfaces, are specified in compliance with DIN 4762 and DIN 4768 (DIN = German Industrial Standard).  


All information and values stated concerning our product portfolio are based on the knowledge optained through a long experience of manufacturing and application.
These figures are for indicative purposes only and may vary (exceed or deceed) according to the particular circumstances. Unknown factors in the applications and practice can considerably change the conditions and reduce and change statements, which may cause the above information to be invalid.
No liability can be accepted for any mistakes or omissions, error and subject to change without prior notice.


The new S.F. Product Catalogue has been released!

Hot of the Press - ask for your personal edition: |  +49 / 8142 / 651 800 Or as download directly here. Individual product categories you find under servi

Surveillance audit of the management system successfully completed

7 August 2019                             For all certifie



Piston Sealings

KD double acting


KE single acting



KDAQ double acting


© Copyright 2020 S.F. Components GmbH. All rights reserved

This website uses cookies

This website uses cookies to improve user experience. By using our website you consent to all cookies in accordance with our Cookie Policy.