Doosan Heavy Industries & Construction required a bolt tensioning solution to tighten nuclear reactor pressure vessel stud bolts. Boltight was contacted to design a hydraulic tensioning tool to achieve a predetermined bolt elongation, without exceeding the reactor head’s maximum allowable bearing stress.
The required bolt load was critically high (14,500 kN), and the space envelope was very small – the radial space available to install and operate the tensioner was particularly tight.
A tensioning system was designed to accommodate this high preload capacity within the space available. In realising these tools, Boltight engineers also incorporated a hydraulic piston retraction function into the design; to enable the equipment to be reset quickly, reducing operator fatigue. To compensate for dynamic joint behaviour, a spherical reaction nut and piston interface was integrated to accommodate any bending effects in the event of flange rotation.
Various safety mechanisms were incorporated to protect both the tools and the operators. Pressure relief valves were installed, and a floating gearbox design was engineered to avert damage should nut misalignment occur. The gearbox directly interfaced the geared nut which negated the need for a costly, heavy socket, and provided the necessary torque to rotate the nut.
Boltight were able to supply a complicated, bespoke design to exacting standards and achieved the tight delivery period set down by the client.
First published in Bolted #2 2017.
CUSTOMER: SUBSEA INNOVATION, UNITED KINGDOM
APPLICATION: OFFSHORE STRUCTURES
BOLTIGHT PRODUCTS: 14 UNITS OF M120 AND 10 UNITS OF M150 BOLT TENSIONERS
PROJECT: STRUCTURAL PIPELINE REPAIR CLAMPS FOR EPRS
Boltight solutions continue to be employed on more and more specialist applications in a multitude of markets worldwide. One example of this is Subsea Innovation, a UK-based company that serves the offshore industry. This company has been supplying subsea structures for over 25 years, and recently secured a multi-million-pound contract in Australia.
For this project, Boltight has supplied tailormade bolt tensioning equipment for structural split repair clamps. These are part of the Emergency Pipeline Repair System (EPRS) for gas pipelines off the north and northwest coasts of Australia. Boltight designed and produced two sizes of tensioner to suit M120 and M150 bolts. These tensioners are used to tighten the main bolts located around the clamp body and are activated remotely using a hydraulic control system.
The tensioners have been designed as per Subsea Innovation’s specifications, with Boltight adding its experience of supplying such solutions. The long-stroke, double-acting design means that they operate in both directions, so they can be reset without recovery to the surface. They are ideally suited for subsea use.
Boltight worked with Subsea Innovation to agree on testing and operational specifications, ensuring that the applied bolt tension is correct and that the overall EPRS system operates properly when called upon. All parts were supplied by Boltight within a strict delivery window.
The EPRS in Australia will act as a contingency if the main lines transporting gas need to be repaired.
The 2017 September issue of Bolted magazine is available now! As with every issue we have filled the magazine with interesting cases and insights from the world of bolting.
In this edition, our theme article focus on lug wear which is a common issue for pivot joints. But why does it occur, what solutions exist and do they solve the root cause of the problem?
You will find out more about Expander System in our customer case, where we visited Danish company Viggo Benz who delivers solutions and equipment for crushing, demolition and sorting.
Also, see how Nord-Lock washers secure containers that transport radioactive substances, where there is no room for equipment failure.
Last but not least, don’t miss out on how and why we now offer lifetime warranty throughout our product range.
Want to receive your complimentary copy of the Bolted magazine? Subscribe here now!
Boltight manufactures both standard and custom built tooling for subsea applications. The subsea tensioners incorporate components that helps to save installation time, cost efficient, protects the environment and conforms to the requirements of the European Pressure Equipment Directive.
All subsea tensioners are assembled, filled with oil and have been pressure tested before dispatch. Boltight subsea tensioning tool is supported by a range of ancillary equipment such as high volume pumps, diver control valves, long length down line and hose reels.
Boltight’s Typhoon range of bolt tensioners offer a high-load, low profile solution for space-restricted applications that demand high and accurate preloads. A solution widely used within the Wind industry where such space-restricted connections are common. Additional convenience features such as a spring loaded gear drive for nut rotation and automatic piston retraction, ensure that Typhoon bolt tensioners are the ideal choice for any application demanding a powerful, portable and user-friendly bolt tensioning tool.
Boltight’s Piston Retraction system takes the hard work out of resetting bolt tensioner piston stroke. Depending on the design of the tensioner, the pump will give automatic piston retraction or assisted piston retraction.
Quick and easy, it saves operation time, reduces operator fatigue, and promotes safe and efficient working practice.
We had a great time at last week’s Fastener Fair in Stuttgart!
This international leading trade show, held once every two years, attracts thousands of visitors from the industry and we would like to thank everyone who stopped by our booth!
We took this opportunity to launch our Lifetime Warranty program, and to share other exciting news from the Nord-Lock Group such as extended temperature range for usage of the steel washers, or introduction of our innovative tensioner VersaTite.
We are looking forward to being your trusted partner in safe and efficient bolting and hope to see you at the next trade show!
Designed with the benefit of more than 30 years experience in the field, Boltight has created a range of tools to meet the challenge of today’s bolt tensioning requirements.
Just watch how easy it is to install these tensioners!