PULP MILL USES ORBITAL WELDING TO REPAIR ITS BOILER
- The two economizer drums have a 30-in. I.D. forcing the welder to work in a very cramped situation.
- To weld the tubes in the upper drum, the welder would either have to kneel or lie down on his stomach inside the drum.
- To install the tubing in the lower drum, the welder would have to lie on his/her back and weld in the overhead position.
- Adding to the welder's discomfort was a high-temperature working environment of 200° F resulting from the necessity of preheating the carbon steel drums and tubes prior to welding.
- The two functions of the boiler are recovery of inorganic chemicals from black liquor to be recycled in the pulping process and the combustion of the organic constituents in the black liquor to produce valuable steam.
- Water to be heated into steam circulates through the tubing in the economizer when the boiler is in operation.
- Previously, the difficult operating conditions under which welders had to work to perform these welds manually resulted in welds of inconsistent quality.
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