Abstract: A drop-in nozzle block (40) formed in two 180° segments (52) that can be simply lowered into position within the nozzle chamber casing of a steam turbine (42). An entire 180° segment can be lowered into position because an inner arcuate portion (58) of the nozzle block fits over and captures mating portions of the casing rather than having the casing capture the nozzle block as in the prior art. Elimination of a hook portion of the casing eliminates the necessity for the prior art procedure of rotating 90° segments into position through an arcuate-shaped slot. The drop-in installation allows closer tolerances to be maintained between the nozzle block and the casing, thereby eliminating the need for the expansion pins used in the prior art. The use of two 180° segments rather than the prior art 90° segments also eliminates the need for a dogleg joint between segments for turbines having eight steam inlet segments.

Abstract: A drop-in nozzle block (40) formed in two 180° segments (52) that can be simply lowered into position within the nozzle chamber casing of a steam turbine (42). An entire 180° segment can be lowered into position because an inner arcuate portion (58) of the nozzle block fits over and captures mating portions of the casing rather than having the casing capture the nozzle block as in the prior art. Elimination of a hook portion of the casing eliminates the necessity for the prior art procedure of rotating 90° segments into position through an arcuate-shaped slot. The drop-in installation allows closer tolerances to be maintained between the nozzle block and the casing, thereby eliminating the need for the expansion pins used in the prior art. The use of two 180° segments rather than the prior art 90° segments also eliminates the need for a dogleg joint between segments for turbines having eight steam inlet segments.

Abstract: A turbine blade assembly is provided which comprises a rotor which is rotatable about a turbine axis of rotation and a plurality of turbine blades supported by the rotor where each of the turbine blades has a root and the rotor is provided with a plurality of grooves which terminate in a projection. Each groove is shaped for holding each root in a manner such that the root and the groove have mutually contacting surfaces which apply a radially inwardly directed restraining force to the root. The root has a bottom facing the turbine axis and the groove has a base which is located radially inwardly of, and faces, the root bottom. Positioned between the root bottom and the groove base is a lock strip and disc spring assembly for pressing together the mutually contacting surfaces of the root and the groove.

Abstract: A high performance steam turbine vane having a novel airfoil shape. The pressure surface of the airfoil has a substantially straight region proximate the trailing edge that provides the airfoil with adequate thickness to prevent distortion during forging. The novel shape on the suction surface is such that a first region of the suction surface downstream of the gauging point is essentially straight. Traveling in the upstream direction, the first region is followed by a second region that has a large amount of curvature. The second region is followed by a third region that has a lower curvature than the second region. The third region is followed by a fourth region of constantly increasing curvature that increases to a curvature greater than the curvature of the second region. The fourth region is followed by a fifth region, ending at the leading edge, of essentially constant large curvature that includes the maximum curvature throughout the suction surface.

Abstract: A platform motion restraint for freestanding blades having Christmas tree shaped roots comprising a plurality of L shaped members which fit in circumferential notches machined in the outer portion of rotor steeples, one leg of the L shaped member being forced into the groove under platform portions of the blade to move the blades radially outward and the other leg filling the gap between adjacent blades.

Abstract: A turbine blade assembly composed of a rotor which is rotatable about a turbine axis of rotation and a plurality of turbine blades supported by the rotor, each blade having a root and the rotor being provided with a groove shaped for holding each root in a manner such that the root and groove have mutually contacting surfaces which apply a radially inwardly directed restraining force to the root, the root further having a bottom facing the turbine axis and the groove having a base which is located radially inwardly of, and faces, the root bottom. The mutually contacting surfaces of the root and the groove are pressed together by means of at least one disc spring compressed between the root bottom and the groove base.

Abstract: A freestanding mixed tuned taper-twisted steam turbine blade having an X-X axis parallel to a rotor axis, includes a root portion having a root center line defined by a root center line radius, a platform portion connected to the root portion; and an airfoil portion connected to the platform portion and having a leading edge, a trailing edge, a convex section-side surface, a concave pressure-side surface and a profiled tip, the platform portion having a concave edge, a convex edge, a first end in vertical proximity to the leading edge of the airfoil portion and a second end in vertical proximity to the trailing edge of the airfoil portion, the concave edge being sloped towards the root center line radius at a predetermined angle of slope to define an arcuate sloped surface, and having a sloped flat cut-out surface formed at the second end of the platform portion, the flat cut-out surface having the same predetermined angle of slope as the concave edge and sloping towards the X-X axis.

Abstract: A retrofitted rotor blade having a longer length than an original rotor blade provided for a steam turbine rotor assembly has a tuned airfoil portion with natural resonant frequencies in a plurality of vibrational directions similar to the original rotor blade. Since lengthening the blade causes a decreased and resonant frequency, a unique combination of tuning techniques raises the resonant frequencies to the required levels. The tip of the retrofitted rotor blade is profiled to increase the natural resonant frequency in the second mode of vibration, which is in the axial direction of the rotor.

Abstract: In turbines, gaps arising between adjacent shrouds of integrally shrouded blades at high temperature are controlled or eliminated using pins inserted into opposing faces of shroud portions. These pins have a coefficient of thermal expansion greater than the integrally shrouded blade material and at least equal to that of the rotor material and, thus, protrude outwardly at operating temperatures. These protruding pins act to close the gap between shroud portions, thereby reducing vibration.

Abstract: A redundant locking system for the closing blades of a circular array of curved Christmas tree-shaped roots of side entry freestanding steam turbine blades which have registering holes in the platform of the closing blades and the blades adjacent to the closing blades which receive pins, the pins fit tightly into the through holes and loosely into the hole in the adjacent blade to lock the closing blades in place and allow each blade to vibrate independently.