Seal construction for fluid swivel joints incorporating a free-floating anti-extrusion device with oil injection system

A sealed fluid swivel joint, comprising:

• a. a first and second adjacent joint rings, means for supporting said joint rings for rotation relative to each other about a common central longitudinal axis and defining a small annular, ring-shaped clearance gap therebetween to allow said relative rotational movement between the first and second joint rings, and an annular seal housing groove being formed in said first joint ring facing said clearance gap;
• b. an annular seal positioned in said annular seal housing groove providing a seal between said first joint ring and said second joint ring, said annular seal including an annular, pliant sealing member, and a rigid annular anti-extrusion ring to prevent the pliant sealing member from being deformed into said clearance gap by a fluid pressure differential existing across said annular seal, and retainer means fastened to said first joint ring for maintaining said anti-extrusion ring in said annular seal housing groove, said fluid pressure differential biasing said annular sealing member against an adjacent sealing face on said second joint ring to provide an effective fluid seal therebetween;
• c. and oil injection means providing a circulating flow of oil intermediate said annular sealing member and the adjacent sealing face on said second joint ring so as to remove generated heat and seal wear debris from the interface between said sealing member and the second joint ring.