The total alignment of the steam path components requires they be "in-line" at all operating conditions and in all directions. This includes "end-to-end" alignment. To achieve alignment it is necessary for the person responsible for this operation to achieve side-to-side measurements sufficient to ensure all stationary components are equidistant from the center on those surfaces needing interaction with the rotating portions of the unit.

The first action step to achieving total alignment is normally to place the bearings at the correct radial height (discussed above and drawn for a multi-section unit in Fig. 2.3.7). The bearings are the major consideration in the total alignment. Once they are set, it then becomes necessary to align the other components (diaphragms, packing heads, oil seals, etc.) so they follow the same catenary at all axial positions along the length of the sections. Figure 2.3.9 shows some small amount of lateral adjustment required to account for the oil shift ("dh"). Normally, this is a relatively small amount below the level that special provision should be made for it but it will cause some small adjustment in the side-to-side hot running clearances.

With bearing heights adjusted, it is necessary to adjust the remaining components. This requires that their height first be set so casing horizontal joints are at the correct height. Various components are then adjusted side-to-side in their correct radial position laterally and vertically. These components are then locked in place.

The methods of establishing the center position for gauging each of these...