Step Seal

It has a special filled PTFE ring with a pre-loaded lip energised by an O ring. The lip is designed to have a contact area with the rod adequate to retain the media at low pressure. As high pressure acts on the O ring it compresses the lip against the rod increasing the contact area and the effectiveness of the seal. The special PTFE ring has the low frictional properties normally associated with this material but is strengthened by additives to reduce creep. It has a low breakout friction so stick-slip is eliminated.

Standard seals are supplied with a nitrile O ring but other materials can be provided. For the best results it is recommended two seals are fitted. The PTFE ring should always be mounted with the sealing lip on the pressure side. A number of material options can be provided to extend operating conditions.

A PTFE step seal and an O-ring used as an energizer can be used in high pressures up to 500bar and for reciprocating motion up to 15 m/s. Temperature range is -50° C to +200° C (depending on the components used for O-ring). Since the PTFE is filled with Bronze or Carbon, the abrasion resistance property is very high.