| 摘要 |
An opening is formed in a tank bottom and a mounting flange for a bottom outlet valve is attached to the tank bottom extending into this opening. This valve mounting flange contains fastener openings. A vertically extending light source is removably attached to the mounting flange, for example with mechanical fasteners. This light source is shined upwardly into the tank and indicates a reference point on the internal surface of the tank top for locating a nozzle opening. This reference point is marked, and a top opening is then formed in the tank shell by workmen located in the tank, usually after rotating the tank 180 DEG . If the tank has been rotated prior to forming the top opening, the tank is again rotated 180 DEG to locate the top opening at the top of the tank. An optional reinforcing plate is then welded to the outside surface of the tank surrounding the top opening. This reinforcing plate contains a reinforcing plate opening. A hollow cylindrical nozzle is then located within the reinforcing plate opening and/or the tank top opening. An alignment fixture including a target is then inserted into the nozzle. The light source from below the tank bottom is then shined into the nozzle and onto the target located in the nozzle. When the light source is pointed at the center portion of the target, the nozzle is tack welded to the tank top and/or reinforcing plate. The light source is then removed from the mounting flange and the fixture is removed from the nozzle. The nozzle is then finish welded to the reinforcing plate and/or to the tank shell. A seal assembly and an operating rod are then inserted into the nozzle. The operating rod is connected to a lading valve in the tank bottom in a known manner.
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