General Electric Company

Ralph Arnold Pollock

John Francis Nolan

Todd Joseph Fischer

Dennis John Werner

Stephen Roger Johnson

The broach assembly includes alternate spacers and cutters arranged in a sub-assembly having a lead at a leading end and a lag at a trailing end. The cutters have side margins in excess of the margins of the spacers for cutting material from the dovetail slots of the turbine wheel as the broach assembly passes through the slots. The bottom or apices of each spacer and cutter are tapered to form a continuously tapered surface along the bottom of the broach assembly. Upon passing the broach assembly through the slot, the assembly is progressively displaced in a radial outward direction to progressively cut the active dovetail slot surfaces. Shims may be disposed in the bottom of the slot to further displace the broach assembly radially outwardly in multiple passes.

Multi-part dovetail repair broach assembly and methods of use

A broach assembly includes an elongated base having a central upward projection and a pair of side flanges and a tapered undersurface. Releasably mounted on the projection are multiple tool holders spaced along the length of the base. The tool holders mount cutters for engaging active surfaces of the wedge slot as the broach assembly is passed through the wedge slot. Shims may be interposed between the tool holders and base to increase the elevation of the cutting surfaces relative to the undersurface of the base to progressively increase the bearing pressure of the cutting surfaces against the active surfaces of the slot during multiple passes of the broach assembly through the wedge slot.

Apparatus and methods for refurbishing generator field wedge form slots

The broach assembly includes alternate spacers and cutters arranged in a sub-assembly having a lead at a leading end and a lag at a trailing end. The cutters have side margins in excess of the margins of the spacers for cutting material from the dovetail slots of the turbine wheel as the broach assembly passes through the slots. The bottom or apices of each spacer is tapered and extends beyond the corresponding surface of the cutter to progressively displace the assembly in a radial outward direction to progressively cut the active dovetail slot surfaces. Shims may be disposed in the bottom of the slot to further displace the broach assembly radially outwardly in multiple passes.

The repair method includes removing eroded or damaged trailing edge portions of partitions in the diaphragm of a turbine, over 50% of the length of the partitions being removed commencing at the trailing edge. A coupon which is a precise replication of a portion of an originally specified partition is welded to the remaining or extant partition portion by a seal weld along the radial length of the coupon on the suction side of the repaired partition and two full penetration welds at the ends of the coupon to secure it to the inner and outer rings or side walls of the diaphragm. The repaired partition is thus substantially identically contoured as the original partition.

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Ballston Lake, NY, United States of America

Ralph Arnold Pollock