Stenso - Hovedkatalog 2019

We recommend the use of back up rings for one ore more of following conditions in service: - pressure over 5MPa(50 bar) - larger sealing splits - higher stroke frequency - high temperature fluctuations - pulsating pressures STR (recommended assembly / mounting sizes for O-rings) Back-up rings of the STR series are produced from special polyurethane elastomer by special process. The material - hardness 95 shore A - has excellent extrusion resistance. It is, however, possible to use endlessly manufactured back up rings for external sealing applications due to their Memory effect. These back-up rings are meant for automatic assembly. Special anti-ageing additives in the material are also effective in dry air and oil. AF-100, 110, 120, 140 andAF-150 Rings of this series are produced by turning, and we recommend specific explana- tions according to specific applications ( see below) Part design application STR endless internal/external sealing static AF-120 endless internal/external sealing dynamic STR slotted internal/external sealing static AF-110 slotted internal/external sealing dynamic AF-110 slotted internal/external sealing static AF-100 spiral internal/external sealing static AF-100 spiral internal/external sealing dynamic AF-140 concave (endless) internal/external sealing static AF-140 concave (endless) internal/external sealing dynamic AF-150 concave (slotted) internal/external sealing static AF-150 concave (slotted) internal/external sealing dynamic Material overview back up rings: Back-up Ring 268 AF-1012 - Virgin PTFE AF-1022 - PTFE with additive AF-2426 - PTFE with carbon AF-4125 - PTFE with glassfiber AF-5640 - PTFE with bronze/additive