Method of making a turbine regenerative seal

Abstract

Abstract A thin, compliant seal for the regenerator of a gas turbine engine or the like and a method of making same. The seal is comprised of a plurality of individual seal elements that are interrelated with each other at their ends to preclude leakage. Two embodiments of end relationships are shown. In one embodiment two of the seal elements have interengaging portions that provide a loose connection between the elements. In the other embodiment, each of the seal ends carries a locating portion that coacts with means on the housing of the regenerator for providing a loose interrelationship between the seal ends. The end interrelationship of the seal elements in each embodiment permits relatively free movement of the seal elements under the influence of thermal expansion. This precludes warping of the seal as would occur if the seal were constructed from a single piece or if the seal was formed from pieces that were rigidly connected to each other. Each of the seal elements includes a first relatively thin, compliant part that is provided with a wear resistant coating that engages a rotating element. The coating is applied to a lightly oxidized surface of a relatively thin substrate which substrate is unstressed to reduce warpage. Cantilevered springs form another piece of each element. These cantilevered springs sealingly engage a static mating surface of the regenerator and resiliently bias the coated surface first piece into sealing engagement with the rotating element. The coating, as has been noted, is applied to an oxidized surface of the first part. In a preferred embodiment the coating is applied after the cantilevered spring is assembled to the first part. This subassembly is then held in a fixture and is preheated. A relatively thin transition layer of coating material is applied to the oxidized surface. The transition coating is formed from a material that will have an exothermic reaction with the oxidized surface. The final, wear resistant coating is then applied to the transition coating while maintaining the temperature and preventing excessive heating and, accordingly, warpage. The use of a thin seal and relatively thin coatings insures compliance of the seal with the mating surface of the rotating element.

Inventors

• 👤 William E Good
• 👤 Grasso Leonard Di
• 👤 James D Hoffman

Bibliographic Details