US Patent 11168573 Circumferential seal assembly with adjustable seating forces

A circumferential seal assembly for use between a higher pressure side and a lower pressure side is presented. The seal assembly includes a primary sealing ring, a second sealing ring, a third sealing ring, and an insert. The segmented primary sealing ring sealingly engages both a face sealing surface along a housing and a radial sealing surface along a rotatable element. The insert is disposed within and directly contacts the housing. The second sealing ring is adjacent to the primary sealing ring and sealingly engages both the primary sealing ring and the insert. The segmented third sealing ring contacts and sealingly engages the primary sealing ring opposite the housing. The insert, the second sealing ring, and the third sealing ring cooperate to form a first cavity adjacent to the second sealing ring and the third sealing ring. The primary sealing ring, the second sealing ring, the insert, and the housing cooperate to form a second cavity adjacent to the primary sealing ring. The insert and the second sealing ring separate the first cavity from the second cavity.