Riser tensioner system for use on offshore platforms using elastomeric pads or helical metal compression springs

摘要

A riser tensioner system 10 is provided for use on offshore oil drilling platforms to support a riser 12 relative to a floating platform. The riser tensioner system 10 uses either elastomeric pads 32 or helical metal springs 100 as an energy absorbing medium, rather than hydraulic, or pneumatic systems. The elastomeric pads 32 or helical metal springs 100 are maintained in compression within a shock absorber housing 76 by a plunger 70 which is compressed by the weight of the riser 12. If the riser tensioner system 10 is arranged to place the shock absorber 20 in tension, the shock absorber plunger 70 is inverted in the housing 76 to maintain the elastomeric pads 32 or helical metal springs 100 in compression. To achieve varied response characteristics, nested inner and outer elastomeric pads 50, 52 or compression springs 102, 106 are arranged to act together. A varied response characteristic may also be obtained by varying the elastomeric pad modulus or the helical spring constant, or by use of conically shaped elastomeric pads 80.