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- After checking that the foundation is complete, annular plates & tank bottom / base plates erection & welding completed as per code.
- Tank Shell ring location marked on the tank base plates and Temporary Structural Members (Elevators) are erected at every 3000mm on the tank ring marking. The Shell plates are erected / placed on these Structural Members and erection & welding of top most shell course plates is completed.
- For fixed roof (cone / dome) tanks, curb angle, roof structures and roof plate erection / welding to be completed and required number of hydraulic jacking units are assembled and erected and aligned inside the tank.
- Special cleats (Lifting and Guide) fabricated earlier as per details given are welded to the lowest tank shell and then hydraulic jacking units are connected to the shell cleats and hydraulic power pack is connected with the jacks through hydraulic hoses.
- On operating the hydraulic power pack, the hydraulic oil starts circulating through hoses to all the jacking units and as the oil pressure increases all the jacks start climbing/ lifting together to complete 1 operation of @ 100 mm lift.
- On completion of 1 cycle all the jacks stay at the lifted position on the jack rod due to a special grip mechanism in the jacking units and the pressure is released from the hydraulic power pack.
- The operation is repeated till the height of erection for placement of next shell is achieved.
- Next Shell plate erection and vertical seam welding is completed and the lifted shell plates are lowered by the jacking units to align with the new shell plate and welding is completed.
- Jacking units are lowered. Cleats are removed and welded to the next shell plates and the operation from Sr. no. 5 to 8 is repeated and the tank erection is completed.
- Erection of spiral staircase, wind girder and other structural supports and radiography and cleaning of shell can be completed simultaneously as the erection of the shell is in progress.
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