INNER BATH ROOF CONSTRUCTION METHOD FOR DOUBLE SHELL TANK

PURPOSE:To obtain construction accuracy for an inner bath substantially equal to that of a tank by constructing an outer bath side plate, lifting inner and outer bath rooves simultaneously by means of an air soft, constructing an inner bath side plate, separating the inner and outer bath rooves from each other, and lowering the inner bath roof to the top of the inner bath side plate. CONSTITUTION:An inner bath roof 1 is connected to an outer bath roof 2 by means of an inner bath roof descending bolt 3', while a sealing member 7' is arranged between the outer bath roof 2 and an outer bath side plate 5 to pneumatically float the outer bath roof 2 and the outer bath side plate 5. When the outer bath roof 2 reaches a specified position, the outer bath roof 2 is fixed to the outer bath side plate 5 by welding, and then an inner bath side plate 4 is constructed. When the inner bath side plate 4 is completed, the inner bath roof descending bolt 3' is loosened to lower the inner bath roof 1 to a top of the inner bath side plate 4. Then both of the roof and the side plate is welded to complete an inner bath. The inner bath roof descending bolt 3' is welded to the outer bath roof 2 to prepare the airtightness of an outer bath. Afterward, the inner bath roof descending bolt 3' is cut and the connection between inner and outer baths is released to cope with the temperature expansion/ contraction peculiar to the inner/outer baths respectively.