Growing lines meet growing demand

TAG’s 7000m2 automated tubular production facility includes a manufacturing unit and large construction hall, extensive wet dock, a blast and paint facility and a 6000t load out quay. Here, TAG is able to roll and weld large diameter tubulars and construct foundations, including monopiles (hollow diameter cylinders driven into the seabed), transition pieces, tripods/jackets (frames with supporting legs) and gravity foundations (large concrete/steel structures). 

The company purchased two 300ton growing lines from ESAB to handle the rotating and positioning of tubular structures up to 350s ton using the growing line production principal. Subsequent investment in two 1000ton growing lines took into consideration demand for cans of larger diameter and length for offshore deep water installations. 

According to commercial director Glenn Wilson, the growing lines are essential for handling the long cylindrical workpieces to minimise alignment, handling and fabrication time: "Companies want to move to deeper waters, so the diameters and the lengths of the cans has significantly changed.”

The new growing lines include ESAB FIT 100 roller beds with built-in hydraulic height adjustment and FIR 500 heavy-duty units for aligning the sections, as well as CD-1000 and Ci-1000 conventional roller beds with rail bogies and anti-creep. 

The alignment is carried out by the FIT and FIR units. The FIR 500 has four independently adjustable rollers to precisely align the workpieces with each other and two cross rollers to lift the section for conveying out the workpiece. The FIT 100 also features independently adjusted rollers to align the workpieces with each other.

The roller beds are of rugged design with durable rollers and oversized bearings. A cast steel gearbox with double worm gear arrangement ensures smooth operation and minimum backlash. A solid state inverter provides precise speed control. 

ESAB roller beds are designed to enable large round items to be welded and handled during rotation welding and are well suited to wind tower production. Using conventional roller beds, the operator manually and mechanically sets the distance between the rollers to different diameters. 

The growing lines provide a fully integrated system with hydraulic fit up, lift and transfer. 

"Many of us at TAG have worked in large fabrication yards, so we were aware of ESAB,” said Stuart Dawson, operations director. "Its equipment is robust and reliable, so it was easy for us to select ESAB both from a technical and commercial perspective.”

"There was also a delivery factor,” continues Dawson. "We had to move fairly quickly to get this custom equipment installed. We were able to inspect the ESAB lines in production and were impressed with how the manufacturing was being conducted.”

A key feature of the ESAB growing line systems was the motorised anti-creep. Dawson explains: "When you fabricate straight cans, they tend not to be too much of a problem, so there is no real technical preference. You just fabricate them and weld them together. The challenge comes with fabricating cones, with conical sections that you have to develop and weld. A cone will want to slide off the manipulators because of its shape. ESAB has an anti-drift system that’s proven to be extremely useful for us. If the monopiles are sliding down, the unit is only allowed to move 300mm and then the manipulators will automatically adjust it from slipping.”

TAG has manufactured tubes to 101m in length, 6.5m in diameter and up to 100mm thick. Their heaviest structure to date is a 6.5m, 650ton tubular.

"Apart from any fit up that needs to be done externally or internally, which happens on the transition pieces, the foundation pieces which go into the seabed generally don’t have any attachments other than paint markings,” explains Dawson.

From the time TAG considered expanding into the renewable energy sector and during the process of defining the new facility, ESAB has provided good support. Dawson concludes: "We tried to future-proof our facility and ESAB helped us with the strategic planning.”