| 摘要 |
<p>An annular sealing apparatus has an annular seal element 18 and a back-up assembly 30 for supporting the seal and preventing or resisting extrusion of the seal. The back-up assembly 30 includes a collar 54 interposed between a support member 40 of the back-up assembly 30 and the end 32 of the seal element 18. The collar 54 prevents or mitigates damage to the support member 40 from the seal element 18. The support member 40 includes a annular ring and section which extends over the surface of the seal 18, preferably comprising plural section 48. The sections bend or pivot outward in response to the expansion of the seal. There may be a second back up element 42, provided between the seal and the first support member, the second back up element 42 also comprising plural sections 52 or petals which overlap with those of the first element to avoid gaps when in the expanded state.</p> |
