Tension Monitor Keeps Fasteners Tight Under High Pressure

When looking for a fastening system to secure main underwater wellhead connections, Cooper-Cameron's in Leeds, England, required a system that could withstand working pressures as high as 10,000 PSI.  Conventional torque-tightening methods, however, couldn't sustain uniform clamp load.  Hydraulic tensioners, for instance, required extra space around the stud and extended length, leading to unpredictable residual bolt tension.

"Because this particular joint is subjected to extreme operating conditions, the studs should be tightened with exacting precision to maintain joint integrity," says Reg Wilson, engineering manager at Cooper-Cameron.  "Rotabolt's tension-controlled fastener creates a uniform clamp load and provides a way to verify the precise level of tension and dependability."

The Rotabolt studs made by Rotabolt Ltd., distributed by EGC Enterprises, Cleveland, have a built-in tension monitoring system that maintains tension at accuracies of ± 5%.  During installation of the wellhead connections, a simple manual test instantly checks tension.

By securing and monitoring load tension in joints under high-pressure conditions, the fasteners are suitable for riser/repair clamps, pipeline flanges, templates, and manifolds.  Other applications include pressure vessels, heat exchangers, and valves.

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