Between the source of production and the eventual destination, be it processing point, export point or final market, pipelines encounter situations that can potentially impose huge strains on their structure, including hills, gullies, bridges, subsidence and trenches in muddy or sandy locations – often with restricted space in which to engineer the lift.
The elastomer lifting cushion technology developed by Pronal and supplied by Air Springs Supply can help mitigate the risks associated with manoeuvring pipelines in a variety of conditions. Pronal is famous for providing the enormously strong lifting bags that raised artefacts from the ocean liner Titanic, 4 km down on the Atlantic Ocean floor.
Experienced pipeline construction company Nacap, which over the past 40 years has laid more than 40,000 km of underground oil, gas, water and chemical pipelines ranging in diameter from 250 to 1,500 mm and reaching lengths of 2,000 km, uses Pronal lifting bags on a variety of its projects.
Nacap has worked on projects such as Epic Energy’s QSN Link to deliver coal seam gas to southern markets, the Dampier to Bunbury Natural Gas Pipeline, the Magnet slurry and return water pipeline, the Tallawarra gas pipeline project, and the Wimmera Mallee Pipeline Project.
The company is helping to ensure safety and security in Australia by using the innovative Pronal lifting bags method of de-stressing pipelines as they are shifted and lifted to overcome and circumvent obstacles, obviating risks that could rupture the pipelines and create safety and supply problems.
Pronal lifting bags, distributed in Australia by Air Springs Supply, are now being used in groups of up to a dozen to gently raise and position sideways pipelines from 8 - 32 inch in diameter.
Guided by strain gauges located along the sections of pipeline, the bags are precision inflated to provide shifts down to a millimetre or two when this is all that’s required – or much bigger steps when these are needed.
In New South Wales, the Mallaty Creek gas pipeline involved horizontal movements of up to 1.4 m using Pronal lifting bags braced with geofabric sandbags. Nacap Construction Managers Hugh Boyd and Roger Vouges worked with Alinta engineering consultant GHD on the project.
While the CLP 67 cushions can each provide up to 67 tonnes of lifting capacity (enough to hoist a decent size locomotive or truck) they spread this force evenly over a broad area of the pipeline and give minute control.
This fine lifting capability was employed on the Simpson’s Creek pipeline, which involved vertical movements only says Jack Walsh, Nacap Construction Superintendent for the project.
“The reason we use them is they give absolute control of the lift and therefore great safety and security of supply. Hydraulics might provide a half an inch of concentrated movement, when we only need one millimetre.”
One of Mr Walsh’s larger lifts, using five bags, involved 238 metres of pipeline passing through a gully. “So there was quite a lot of weight involved,” he says. Using a diesel 180 cubic feet per minute compressor, load sensors and the gauges and valving provided with the bags, the pipeline was repositioned to obviate the effects of slope and ground subsidence.
“In that job, and indeed in all jobs, safety is number one priority, absolutely. That’s what we are all focussed on – the whole team, the load control system people, the stress gauge people, the engineers, the client – we are all focussed on security of the workforce, the infrastructure and the supply of the contents of the pipeline.
“Nothing happens, nothing moves until everyone is happy with the process step by step and until it is signed off. Risk management, risk elimination, is paramount. That’s one of the reasons why the Pronal lifting bags are so good – they treat the lift with kid gloves. They are very central to the task.
“With them the lifts become a relatively straightforward two-man job, one each side of the pipe. The bags are easy to position and extremely robust,” said Mr Walsh.
Air Springs Supply National Sales Manager Simon Agar says the compact lifting ability of the Pronal bags can be a major asset in mining, petroleum, gas and infrastructure applications.
“Especially in remote, rugged and sometimes muddy or sandy locations – including trenches – it can be difficult to provide crane access overhead or to obtain sufficient clearance and a firm foundation for a lift from underneath.
“These tough, seamless and versatile lifting cushions can delicately raise loads ranging from pipelines of all types to trucks, tracked vehicles, beams, bridge components, building components, machinery and resource development structures,” he says.
Pronal’s newest cushions range from ultra-thin bags (just 20 mm thick deflated) that can lift weights of up to 67 tonnes each, to powerful spreading cushions that can exert hundreds of tonnes of force to part plant and machinery components for servicing, or to extract quarried material. Complementary low-pressure CPB Maxi-Lift cushions can be used on land and under water, offering greater strokes of up to 700 mm (or 1,400 mm where a pair are employed).
“These are superbly engineered lifting cushions developed for industrial, military and civil tasks by the French elastomer specialists Pronal,” said Mr Agar.
“The materials used are so tough and durable that they are used to recover immobilised aircraft, for example, or to lift tanks or split rocks in quarries.
“In addition to the standard models – such as the workhorse 920 X 920 mm square cushion – a major advantage of Pronal cushions is that they can be custom-engineered to particular shapes and sizes to perform particular tasks as they are inflated by compressors or portable air cylinders or pumps.
“Sometimes it is not necessary or desirable to use cranes, slings or cylinders for lifts that present particular technical challenges in terms of lifting surfaces or surfaces to which lifting force is to be applied. Where considerable investments may be contemplated in custom-engineering a conventional lifting platform, it may be well worth considering the simple principle of pneumatic actuation,” said Mr Agar.
