A smart seal energizer from shape memory alloy

Harsh operating conditions can strongly reduce the seal’s lifetime, potentially damaging people, and the environment. One solution to this challenge is the use of actuatable seals which are able to adapt to the operating conditions. The high operating displacement and comparably low tension force, combined with the freedom of design make a shape-memory-alloy (SMA) the perfect actuator for polymer seals. This work presents a proof of concept for a PTFE seal energized by a SMA wire. The wire is wrapped around the circumference of the seal and activated by means of induction. When the wire is activated, it constricts in length and increases the radial load of the seal. Due to the tunable radial load, the sealing function and friction properties can be tailored to the operating conditions in application.