Tensioning permits the simultaneous tightening of multiple bolts. Tensioners are connected in sequence via a high pressure hose assembly to a single pump unit. This method ensures that each tensioner develops the exact same load and provides a uniform clamping force across the joint, avoiding damage and ensuring a secure sealed connection is achieved.
Tensioning is the direct axial stretching of the bolt to achieve preload which ensures that inaccuracies created through friction are eliminated. Simple hydraulic pressure replaces the mechanical effort to create torque however tensioning does require longer bolt lengths and a suitable seating area around the nut.
Compared to other less accurate tightening methods, HTL’s range of Hydraulic Tensioners allows for:
As the bolt behaves like a spring, as soon as the pressure is released the bolt is under tension and contracts, this creates the required clamping force across the joint. Tensioning allows for 100% tension to occur straight away, saving time topside and also subsea.
Tensioning processes can be set up using either a 50% or 100% tensioning procedure. A 50% tensioning procedure is where only half the bolts are tensioned simultaneously then relocated to the remaining bolts. Alternatively, a 100% tensioning procedure can be used, where all the bolts are tensioned simultaneously. However, this requires more tools to cover all bolts on the joint.
The innovative spring return feature allows HTL’s Spring Return Tensioners to be used across multiple industry sectors, including oil and gas, power generation, petrochemical and related industries.
Designed to increase and improve the productivity and the safety of the operator, the spring return design enables automatic piston retraction at the end of the tensioning sequence, ensuring the tools are prepared and ready to be removed and applied for the next cycle.
In comparison to traditionally designed tensioners, the HTL range of Spring Return Tensioners allows ease of use for the operator through their enhanced design which includes an anti-slip tool surface to improve grip. The design also incorporates a dual port which allows the operator to daisy chain multiple tensioners together, removing the need and expense of ‘T’ pieces.
All models within the range have a stroke of 10mm and cover ranges from 3/4” – 4” bolts making them suitable for use on a vast range of flange sizes. All models within the range offer both metric and imperial inserts as well as oversized versions for galvanized studs.
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TIP: the number of hoses required is the same as the number of tools to be linked. A simple formula to remember.
HTL’s Subsea Tensioners provide the most cost effective solution to subsea bolt or stud tightening.
With a stroke of 30mm and covering bolt ranges from 3/4” to 3 1/2″, HTL’s Subsea Tensioner’s also feature a Quick Release Nut to improve diver safety and productivity whilst minimising diver fatigue.
Features and Benefits:
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Related articles: http://www.hiretorque.co.uk/advantages-of-controlled-bolting-techniques/