CPC E21B 33/1216 (2013.01) [E21B 33/1208 (2013.01); E21B 33/128 (2013.01); F16J 15/18 (2013.01)] | 16 Claims |
1. A back-up ring system, comprising:
an outer C-ring;
an inner C-ring that mates with the outer C-ring, the inner C-ring comprising a first rupture point; and
a ring sheath that fits onto the inner C-ring, the ring sheath comprising:
a cut-out region; and
a second rupture point,
wherein the inner C-ring further comprises a blocking segment that angularly offsets the first and second rupture points,
wherein the cut-out region of the ring sheath mates with the blocking segment of the inner C-ring,
wherein the ring sheath further comprises a ‘7’ shaped cross-sectional profile, and
wherein a lower branch of the ‘7’ shaped cross-sectional profile is tapered.
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