The purpose of this report is to provide design, application and maintenance engineers with basic information on the use of metallic Spring Energized sealing devices when used as piston (OD) and rod (ID) seals in aircraft fluid power components such as actuators, valves, and swivel glands. The Spring Energized seal is defined and the basic types in current use are described. Guidelines for selecting the type of Spring Energized seal for a given design requirement are covered in terms of friction, leakage, service life, installation characteristics, and interchangeability. Spring Energized seals can also be made in various forms and types, including face seals (internal and external pressure sealing types), and rotary variants too. These further types will not be discussed in this document, but many of the same principles apply for them as well.
The SLIPPER SEAL is defined and the basic types in current use are described. Guide lines for selecting the type of Slipper Seal for a given design requirement are covered in terms of friction, leakage, service life, installation characteristics and interchangeability.
This SAE Aerospace Standard (AS) covers solid polytetrafluoroethylene (PTFE) retainers (back-up rings) for use in static glands in accordance with AS5857. They are for use in hydraulic and pneumatic system components as anti-extrusion devices in conjunction with O-rings, packings and other elastomeric seals. Because of the construction of groove dimensions, back-ups specific to rod applications are designated “R” - Rod (Female), back-ups specific to piston applications are designated “P” - Piston (Male). Retainers specified herein have been designed for a temperature range of -65 to 275 °F (-54 to 135 °C) and a nominal operating pressure of 3000 psi (20.6 MPa) for code 09 material and 5000 psi (34.3 MPa) for code 10 material. Material codes are based on AMS 3678 material types.
This SAE Aerospace Recommended Practice (ARP) provides an overview of the various types of polytetrafluoroethylene (PTFE and TFE) back up rings for hydraulic and pneumatic fluid power applications, including their advantages and disadvantages.