Carbon radial seal

A machine comprising:

• an outer member;
• an inner member having an outer diameter (OD) surface;
• and
• a seal system comprising:
• a seal housing mounted to the outer member and having a first wall and a second wall;
• a first seal stage contacting the inner member outer diameter (OD) surface and the first wall;
• a second seal stage contacting the inner member outer diameter (OD) surface and the second wall;
• and
• a wave spring biasing the first and second seal stages axially apart from each other, wherein:
• the first seal stage comprises a plurality of seal segments interfitting end to end and each segment having:
• a first end;
• a second end circumferentially opposite the first end;
• a first face;
• a second face axially opposite the first face;
• an inner diameter (ID) face;
• and
• an outer diameter (OD) face having a circumferential groove and a single radially protruding lug;
• the second seal stage comprises a plurality of seal segments interfitting end to end and each segment having:
• a first end;
• a second end circumferentially opposite the first end;
• a first face;
• a second face axially opposite the first face;
• an inner diameter (ID) face;
• and
• an outer diameter (OD) face having a circumferential groove and a single radially protruding lug, the radially protruding lug between the circumferential groove and the second face;
• for the segments of the first stage and the second stage the outer diameter (OD) face has respective radial reliefs at a first circumferential end and a second circumferential end of the protruding lug;
• the first stage and the second stage each comprise a garter spring holding the seal segments together;
• and
• the housing further comprises:
• an inner diameter (ID) surface having a plurality of recesses receiving the lugs of the first stage and the second stage to circumferentially retain the first stage and the second stage.