Apparatus for attenuating vibration of a tubular member

Abstract

Apparatus for attenuating vibration of a tube includes a cable disposed in the tube and spaced-apart attenuating assemblies mounted on the cable for frictionally engaging the wall of the tube in order to damp vibration of the tube. The assemblies also add rigidity to the tube in order to stabilize the tube against vibration. Each attenuating assembly comprises two spaced-apart end fittings mounted on the cable. A heat vaporizable insert is interposed between the end fittings for maintaining the end fittings in their spaced-apart relationship until the insert vaporizes. A preloaded coiled spring, which interconnects the end fittings and surrounds the insert, biases the end fittings towards each other after the insert vaporizes. A tubular, flexible and braided sheath, which is interposed between the end fittings, surrounds the spring and has respective ends thereof attached to the end fittings. When the insert vaporizes, the spring biases the end fittings closer together, thereby axially shortening the sheath. The braided sheath radially expands as it axially shortens and frictionally contacts the inner wall of the tube to damp the tubular member's vibration. Moreover, the presence of the attenuating assembly in the tube adds rigidity to the tube for stabilizing the tube against vibration.