Air cycle machine seal plate and seal land

A seal assembly for an air cycle machine comprising:

• an insulator seal plate having a bore, wherein the insulator seal plate is constructed from a carbon fiber material;
• a seal having an outer diameter engaging the bore in an interference fit relationship, and the seal including an inner diameter provided between lateral sides defining a first width, the inner diameter providing a seal land configured to engage a rotating surface, the outer diameter to the inner diameter providing a first ratio of 1.30-1.31, and the inner diameter to the first width providing a second ratio of 1.59-1.61, wherein the seal has an annular base extending radially outward from the seal land and including a second width, the first width to the second width providing a third ratio of 1.46-1.53;
• wherein the insulator seal plate includes an annular support providing the bore and including an annular flange against which the seal abuts, the bore including spaced apart recesses axially aligned with the ends of annular base and arranged adjacent to the flange and a lip that is spaced from the flange, the lip axially retaining the seal relative to the insulator seal plate in an installed condition;
• and
• wherein the seal has an annular base extending radially outward from the seal land and including a second width, the first width to the second width providing a third ratio of 1.46-1.53, wherein the second width is nominally about 0.405 inch, the annular base received in a snap-fit relationship with respect to the insulator seal plate.

An air cycle machine comprising:

• turbine and compressor housings respectively having a turbine and a compressor;
• an insulator seal plate fastened between the turbine and compressor housings, the insulator seal plate having a bore;
• a seal constructed from a polyimide and having an outer diameter engaging the bore in an interference fit relationship, and the seal including an inner diameter provided between lateral sides defining a first width, the inner diameter providing a seal land configured to engage a rotating surface, the outer diameter to the inner diameter providing a first ratio of 1.30-1.31, and the inner diameter to the first width providing a second ratio of 1.59-1.61;
• a rotor shaft disposed in the seal and including knife edges extending from the rotor shaft to the seal land, the rotor shaft supporting the turbine and the compressor;
• and
• wherein the seal has an annular base extending radially outward from the seal land and including a second width, the first width to the second width providing a third ratio of 1.46-1.53, wherein the second width is nominally about 0.405 inch, the annular base received in a snap-fit relationship with respect to the insulator seal plate.

A method of installing a seal into an air cycle machine comprising:

• pressing a seal into an insulator seal plate to engage an outer diameter of the seal with the insulator seal plate, the seal including an inner diameter provided between lateral sides defining a first width, the inner diameter providing a seal land, the outer diameter to the inner diameter providing a first ratio of 1.30-1.31, and the inner diameter to the first width providing a second ratio of 1.59-1.61, wherein the seal has an annular base extending radially outward from the seal land and including a second width, the first width to the second width providing a third ratio of 1.46-1.53, wherein the second width is nominally about 0.405 inch, the annular base received in a snap-fit relationship with respect to the insulator seal plate during pressing;
• machining the inner diameter after the pressing step;
• inserting a rotor shaft into the seal and providing a clearance between the seal and the rotor shaft of nominally about 0.003 inch;
• and
• supporting a turbine on the rotor shaft on one side of the insulator seal plate and supporting the compressor on the rotor shaft on the other side of the insulator seal plate.