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How Does A Growing Line System For Vessel or Wind Tower Fabrication Work?

Posted by Ryan Holt, P.Eng on Jun 23, 2016 10:26:36 AM

LJ Welding Automation

 Introducing the LJ Growing Line System

 LJ has recently introduced a new and superior system for handling cumbersome fit up of long heavy vessels, tanks and tower sections with the launch of our 40TA (40 Ton capacity) and 60TA (60 Ton capacity) growing line systems.  

What Is A Growing Line System?

Pipe or vessel growing lines allow the user to easily fit up circular weld joints on heavy fabricated vessel sections, traditionally done manually using cranes, wedges, and other laborious processes that are cumbersome, slow and potentially dangerous, all through an easy to use control pendant or HMI touch screen system.  Larger capacity systems are also available on request.


  1. Superior fit-up capabilities including powered elevation, side shift, track drive features, and indexing features which allow the operator to efficiently and safely line up and "grow" heavy vessel sections during fit up.  
  2. Allows for the assembly of cans while minimizing the use of cranes, making it ideal for wind towers, tank or vessel manufacturing applications where numerous sections are being joined.
  3. Enables operator to assemble and relocate a vessel or tower which may be heavier than the lift capacity of overhead cranes.
  4. Allows for "growing" of the fabricated vessel away from the welding system; this is more efficient because the column and boom welding manipulator can remain in the same location for maximum productivity during welding.
  5. Eliminates the need for wedges and inefficient/potentially unsafe manual jacking systems to align the cans.


Step 1: Place the first 2 cans or vessel sections on fit up bed, and rotate one can so that the seam is at 180 degrees from the seam of the other section.

pipe growing line turning rolls for fit-up

Step 2: Move the fit up carriage to match the cans using the elevation, side/side shift and track drive features. The fit up is done with a single operator using a pendant remote control.


vessel growing line tank turning rollers

Step 3: The fit up rolls are then used to adjust the gap between the cans. Once the gap is closed and the gaps are fully aligned, then the weld can be tacked.

pipe growing line vessel rotators

Step 4: Continue additional fit up around the full circumference of the cans, and place tack welds as required.

growing line welding system for vessel fabrication

Step 5: If making use of LJ's automated open arc root column and boom welding manipulators, move into place and complete the internal ID weld.

weld head on column and boom manipulator

Step 6: After the inside root pass is complete, the welding manipulator is then repositioned to do the outside circumference of the cans, typically utilizing the submerged arc process.

submerged arc welding manipulator

Step 7: Next, repeat the fit up and the column and boom manipulator welds as previously completed. You can then "grow the line" until it has reached its maximum length.


  • Efficiency: cycle time savings of 50-65% have been reported by LJ's customers using the growing line system, when compared with traditional manual methods.
  • Safety: worker safety is increased significantly as the work pieces stay in full control, on the rolls, throughout the entire fit up and fabrication process.
  • Quality: a significant decrease in rework and higher quality is typical when using the growing line system, as the control over joint fit up is vastly improved.

Would You Like More Information About The Growing Line Fit Up Bed System? Request a free consultation with one of our product specialists below.

Automated welding demonstration


Topics: Productivity

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Posted by Ryan Holt, P.Eng
Ryan is a Partner and the Chief Operations Officer for LJ Welding Automation.
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