ADDISONMCKEE BENDS TO THE NEEDS OF THE SUBMARINE REFURBISHMENT PROGRAMME.
30 June 2003 - Addison McKee

Required for use in the refurbishment programme of Britain’s fleet of Nuclear Submarines, the model supplied by the Preston-based firm is a Databend DB120 CNC “Full Boost” Pipe Bending machine which, as its name suggests, enables pipes to be powered into the point of bend in order to prevent thinning of the pipe wall.

Experience and involvement

Devonport Dockyard’s Pipe Shop Manager, Mr Ray Burch, initially contacted
AddisonMckee during 2001 in order to discuss his specific requirements. Whilst existing AddisonMckee equipment was already in place at Devonport, Mr Burch was also fully aware of the company’s experience and involvement in building both large-scale and special purpose pipe bending machines. This was because, before the decline of what used to be known as the “British Shipbuilders”, AddisonMckee had supplied large pipe bending technology to every division of British Shipbuilders across the UK and Northern Ireland.

With bending capacity capabilities ranging from 90mm nominal bore through to 220mm, and with wall thicknesses of pipes of up to 12.7mm, based on maximum size pipes, these robust, well-proven machines have also been exported to shipyards worldwide – including countries in Europe, the USA and Korea. A 275mm capacity pipe bender was also supplied to a shipyard in Shanghai.

For the Devonport Royal Dockyard, the deciding factor in awarding the contract to
AddisonMckee was twofold:

· Firstly, the experience that AddisonMckee had gained in building large pipe bending machines within the Shipbuilding Industry over the past 20 years provided the necessary confidence that Devonport sought – especially as existing Addison
machines could be touched, examined and appraised, with excellent user
testimonials readily available from customers.

· Secondly – and more importantly – the requirement was for pipes to be bent at a
given 2 x pipe diameter centre line radius of bend (maximum) and to have a
minimum thinning of the pipe wall thickness of not greater than 12% at any given
point.

This second requirement is part of the Marine Specification and was something that
AddisonMckee’s Databend 120 CNC controlled Pipe Bending Machine with Full Boost
push-bend technology was built to achieve.

Push-bend “Full Boost” Technology.

With considerable experience in “Full Boost” technology during the bending process
(By pushing more of the tubular metal into the tooling any potential weakness or thinning at the point of bend is greatly reduced.), AddisonMckee’s expertise allows a pipe to be powered into the bend by applying pressure in tonnes down the column of the pipe whilst bending, in order to prevent unnecessary wall thinning of the pipe wall on the various types of materials used. For Devonport, this factor was an absolute “set in stone” must due to the importance placed on the safety of the submarine and crew when below seas.

Exceeding Marine Specification.

Following the installation of the Databend DB 120 machine, the requirement stipulated for pipe wall thinning was achieved well within the Marine Specification by some large margins. Indeed, in certain cases, wall thinning of just 7% was accomplished - dependent on the material and wall thickness of the original pipe.

Costly alternatives.

The only other alternatives available to the dockyard, in order to produce bends that were within specification, were either too costly or too impractical. These options comprised either using cast elbows, welded in-situ, or for the pipe to be filled and “hot bent”.

The use of welded cast elbows, however, would also incur the additional expense of both pressure testing and x-raying to ensure joint integrity. Whereas, the process of filling and hot bending, as well as being highly time consuming, would also involve costly cleaning up of the pipe after completion.

Since taking delivery of the Databend DB 120 ”Full Boost” machine, Devonport Pipe Shop manager, Mr Ray Burch, has been delighted with its performance and the assistance given by the Preston firm to ensure a smooth transition from old, established methods into the world of new technology.

“As a result of delivering and installing the Databend DB120 “Full Boost” machine at
Devonport”, commented Mr Burch, AddisonMckee has helped bring us into the highly technical world of pipe bending, whilst providing an additional in-house bending capacity that will also allow us to take on contract bending for other and similar industries.”

Enhanced control and versatility.

Capable of bending tubing of a maximum diameter of 114mm, a maximum wall thickness of 8.5mm and a maximum radius of 600mm, the hydraulically powered Databend DB 120 machine features a fully programmable 4-axis CNC control.
About Databend technology.

At the heart of AddisonMckee tube benders, “Databend” is an intelligent, flexible computer controlled system that has the capacity to provide complete control, immediate reaction to commands and display total machine operating status. Through a touch screen interface, all machine and axis moves are selected by the operator. Fundamental to the Databend system, a unique “teach mode” also eliminates the need for bespoke machine software sequences, allowing the machine to be “taught” specific configurations for the creation of specific shapes and improved repeatability.

Advanced, yet proven features.

Easy-to-operate and featuring AddisonMckee Windows NT4 software with enhanced 3-D graphics and touch-screen programming, the Databend controller harnesses Siemens 840D control technology, incorporating Profibus fieldbus wiring. World-class design.

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